Current Status of Soil Management in Andhra Pradesh

Transcription

1 Current Status of Soil Management in Andhra Pradesh Dr. A. Sreenivasa Raju CONSULTANT - Soil Management 2012 Bharathi Integrated Rural Development Society (BIRDS) Strategic Pilot on Adaptation to climate Change (SPACC) Kakatiyanagar, Habsiguda, Hyderabad ANDHARA PRADESH 1

2 S.No. Contents P.No. ACRONYMS 9 EXECUTIVE SUMMARY Introduction Background Objectives of the Study Methodology adopted Andhra Pradesh state Soils of Andhra Pradesh Red soils Red sandy soils Red earths Red loamy soils Laterite soils Black soils Deltaic alluvium Coastal soils Salt affected soils Saline soils Saline-alkali soils Non saline alkali soils Surveys for assessing soil fertility status Status and management of soil organic carbon Influence of land use systems on soil organic carbon Influence manures on soil organic carbon Earthworms population dynamics and vermi composting Evaluation of organic manures Evaluation of green manures in rice based systems Crop residues management Groundnut production system at Anantapur Management of nutrients Nitrogen Management of fertilizer N 35 a) Rice 35 b)other cereals 36 c) Oilseed crops 36 d) Chillies 36 e) Cotton 37 f) Sugarcane 37 g) Mesta Residual effects of applied N Phosphorus Management of fertilizer P 39 a) Rice 39 b) Maize 40 c) Sorghum 40 2

3 d) Bajra 41 e) Ragi 41 f) Oilseed crops 41 g) Pulse crops 41 h) Sugarcane P - Utilization studies using tracer techniques Potassium Management of fertilizer K 44 a) Rice 44 b) Maize 44 c) Oilseed crops 44 d) Pulse crops 44 e) Cotton 44 f) Sugarcane 44 g) Chillies 45 h) Other crops Response ratios for major nutrients Calcium Magnesium Sulphur Management of fertilizer S Micronutrients Zinc Iron Manganese Copper Boron Molybdenum Combined application of nutrients Nitrogen and phosphorus Nitrogen and potassium Nitrogen and sulphur Phosphorus and sulphur Phosphorus and zinc Nitrogen, phosphorus and potassium Nitrogen, phosphorus and sulphur Combined application of micronutrients to horticultural crops 53 a) Tomato 53 b) Grape Frontline demonstrations Microbiological studies Use of N bio fertilizers 54 a) N-Fixing bacteria 55 b) Azolla 55 c) P-bio fertilizer 57 d) Role of bio fertilizers Microbial transformations in soils 58 3

4 9.11. Integrated Nutrient Management Crops 58 a)rice 59 b) Maize 60 c) Sorghum 60 d) Sugarcane 60 e) Cotton 61 f) Greengram 61 g) Blackgram 61 h) Bengalgram 61 i) Soybean 61 j) Groundnut 61 k) Castor 62 l) Sesamum 62 m) Sunflower 62 n) Safflower 62 o) Turmeric 62 p) Onion 62 q) Sweet potato 63 r) Vegetable crops 63 s) Acid lime 63 t) Medicinal plants Cropping systems 64 a) Rice sunflower 64 b) Tomato onion 64 c) Mesta based systems 64 d) Rice-rice 65 e) Rice-maize 65 f) Sunflower-sunflower 66 g) Sorghum-sunflower 66 h) Rice-pulse 66 i) Maize-groundnut 66 j) Maize-soybean 67 k) Sorghum-greengram 67 l ) Turmeric-maize intercropping Influence of INM on soil and plant N INM in dryland agriculture Nutrient gains in INM Use of components of INM by farmers of Andhra Pradesh Management of fertilizers in problem soils Soil test crop response correlation studies Paddy 79 a) Surekha 79 b) Pothana 80 c) Surekha Kharif Maize Jowar Sunflower 81 4

5 Onion Tomato Coriander Colocasia Chillies Cotton Sugarcane Status and management of salt affected soils Quality of waters Management practices suggested for irrigation with saline waters Soil pollution Urban solid wastes Industrial effluents Sewage waters Sewage sludge Status of heavy metals in peri-urban Hyderabad Absorption of heavy metals by crops and animals Amelioration of polluted soils Effect of aqua culture on soil and water quality Management of soil physical environment Effect of tillage on soils and crops Land management practices Effect of conservation tillage Effect of physical environment on certain plant parameters Relationships between soil separates and water retention Movement of water Scheduling of irrigation to crops Method of irrigation and mulching Influence of applied nutrients on soil physical conditions Soil moisture studies Soil management aspects Alfisols Vertisols Inceptisols Entisols Oxisols Salt affected soils (Aridisols, Alfisols and Inceptisols) Soil quality Land and soil suitability in mandals having BIRDS projects Survey of farmers in dryland areas Prakasam Chittoor Kadapa Nalgonda Mahabubnagar Kurnool Anantapur 115 5

6 19. Current status of soil management by dryland farmers General information Soil problems Use of manures Use of fertilizers Conclusions and recommendations References 119 Appendices I to IX 124 ***** 6

7 List of tables S.No. Particulars P.No. 1. Description of agro-climatic zones of Andhra Pradesh Major soils of Andhra Pradesh and their distribution Area, production and productivity of principal crops in Andhra Pradesh ( and ) Status of soil organic carbon in and around the fields of Agricultural Research Station, Anantapur District wise data on soil samples analyzed by STLs ( ) Changes in fertility indices of soil organic carbon in different districts Beneficial effects of pre kharif sole/dual use legume green manures on kharif rice Residual effects of pre kharif green manures on yield and N uptake of rice based rabi crops Grain and straw yields and important soil parameters in long term studies on crop residue management Nitrogen management strategies for low land rice crop under different situations Efficient management practices for N in ID crops grown in Andhra Pradesh Crop specificities for soil phosphorus fractions Critical levels of potassium in soils for different crops Extent of S deficiency in soils of different crops Tolerance levels of different rice varieties for Zn deficiency Extent of micro nutrient deficiencies in soils of Andhra Pradesh and India Crops exhibiting nutrient deficiencies and their corrective measures Bio fertilizers produced and supplied to farmers by ANGRAU in Effect of N sources on use efficiency of applied N by rice crop Recent studies on INM Trends in use of manures by farmers of Andhra Pradesh Trends in use of fertilizers by farmers of Andhra Pradesh Awareness among farmers of Andhra Pradesh about certain components of INM in crops Fertilizers applied by farmers under different situations during in Scarce Rainfall Zone Salinity tolerant varieties of different crops Specifications for drainage pipes laying out in salt affected fields Available water capacity in soils of different districts Soil moisture ( mm-at 0-30cm depth ) fluctuations throughout the season under different methods of primary tillage Moisture stored in the profile with use of PVA Land and soil suitability status in mandals selected for study by BIRDS Status and deficiencies of cationic micronutrients in soils put to rice and groundnut crops Status and deficiencies of cationic micronutrients in index leaves of rice and groundnut crops 111 7

8 List of figures S.No. Particulars P.No. 1. Agro - climatic zones of Andhra Pradesh Soil water balance at different stations - Andhra Pradesh 98 List of Appendices S.No. Particulars I Proforma for Soil Management in Drought Prone Districts of Andhra Pradesh 124 II. General information of the districts surveyed 136 III. Irrigation sources for crops grown in dryland districts 137 IV. Soil problems existing in the fields of farmers surveyed 138 V. Different manures being used by farmers of dryland districts 139 VI. Different fertilizers being used by farmers of dryland districts 140 VII. Different aspects related to materials and their management 141 VIII. Awareness about bio fertilizers, INM and organic farming 142 IX. Source of knowledge on use of manures and fertilizers by farmers 143 *** ** 8

9 Acronyms AICRIP ANGRAU ARI AWHC BBF BD BGA BIRDS BOD CARE CARVE CBOs CEC COD CPE DAP DAT DHA DIPA DOR DRR DTPA EC ESP ET FAO FYM GEF GLF GM GVS ICRISAT INM IW K 2 O K 2 SO 4 LC LGP MOP MSL MWD NBSS & LUP NGOs NGRI NRCS All India Coordinated Rice Improvement Project Acharya N. G. Ranga Agricultural University Agricultural Research Institute Available Water Holding Capacity Broad Bed and Furrow Bulk Density Blue green Algae Bharati Integrated Rural Development Society Biological Oxygen Demand Centre for Applied Research and Extension Collective Activity for Rejuvenation of Village Arts and Environment Community Based Organizations Cation Exchange Capacity Chemical Oxygen Demand Cumulative Pan Evaporation Days After Planting Days After Transplanting De hydogenase Activity Development Initiatives and People s Action Directorate of Oilseeds Research Directorate of Rice Research Diethylene Triamine Penta Acetic Acid Electrical Conductivity Exchangeable Sodium Percentage Evapo Transpiration Food and Agriculture Organization Farm Yard Manure Global Environmental Facility Gandhamguda Land Fill Green Manuring Gram Vikas Samstha International Crops Research Institute for Semi Arid Tropics Integrated Nutrient Management Irrigation water Potassium oxide Potassium sulphate Labile Carbon Length of Growing Period Muriate of Potash Mean Sea Level Mean Weight Diameter National Bureau of Soil Survey & Land Use Planning Non Governmental Organizations National Geophysical Research Institute National Research Centre for Sorghum 9

10 NSP OC PARTNER PM P 2 O 5 PSB PSM PVA RD RDF RDFN RDK RDP RP RSC REY SAFE SAID SAMETI SAR SCU SDA SLWM SOI SOP SPACC SQI SRS SSP STCR STLs TDS TRP TSS UIDA USW(s) VAM VC WUE Nagarjuna Sagar Project Organic Carbon People s Activity and Rural Technology Nurturing Ecological Rejuvenation Poultry Manure Phosphorus pent oxide Phosphate Solubilizing Bacteria Phosphate Solubilizing Micro organisms Poly Vinyl Alcohol Recommended Dose Recommended Dose of Fertilizer Recommended Dose of Fertilizer Nitrogen Recommended Dose of Potassium Recommended Dose of Phosphorus Rock Phosphate Residual Sodium Carbonate Rice Equivalent Yield Society for Sustainable Agriculture and Forest Ecology Social Awareness for Integrated Development Staff of Agricultural Management and Extension Training Institute Sodium Adsorption Ratio Sulphur Coated Urea State Department of Agriculture Sustainable Land and Water Management Survey of India Sulphate of Potash Strategic Pilot on Adaptation to Climate Change Soil Quality Index Sri Ram Sagar Single Superphosphate Soil Test Crop Response Correlations Soil Testing Laboratories Total Dissolved Solids Tryptophan Total Soluble Salts Uppal Industrial Development Area Urban Solid Waste(s) Vesicular- Arbuscular Mycorrhizae Vermi Compost Water Use Efficiency ***** 10

11 EXECUTIVE SUMMARY Soil is the most precious natural resource, on proper management of which the existence of civilization or a society in a given area depends. The increase in population is putting a continuous pressure on soils leading to their degradation and making them gradually unfit for cultivation of crops. The variations now-a-days occurring in climate are making crop production a risky avocation to farmers in general, and dryland farmers, in particular. The resource poor dryland farmers are not even adopting proper technologies to conserve soil and water for realizing the best possible yields of crops in such adverse conditions. Keeping these in view, the Bharati Integrated Rural Development Society (BIRDS) took up a project entitled Strategic Pilot on Adaptation to Climate Change (SPACC) in 7 dryland districts viz., Prakasam, Anantapur, Chittoor, Kurnool, Kadapa, Mahabubnagar and Nalgonda in Andhra Pradesh with the assistance of 10 Partner NGOs for a period of 3 years with the objectives of improving the knowledge of farmers through documentation of available literature on soil management, dryland agriculture etc., making them aware of the technologies developed by conducting pilots on sustainable land and water management practices and educating them through climate change schools, besides providing them a platform for scaling up the climate change adaptation measures suitable for improving the crop production in drought prone areas. As a part of the project work, the literature on current status of soil management in Andhra Pradesh has been taken up for reviewing besides getting responses from at least 15 farmers in selected mandals of the districts concerned. A questionnaire specifically developed for this purpose was utilized for recording responses on their present way of managing the soils and also the inputs needed for sustaining production of crops on their soils. Andhra Pradesh is fifth largest state in India with a geographical area of m ha.several important crops are grown on its soils. However, 65 percent of the cultivated area in the state falls under dryland agriculture. This area is drought prone with erratic rainfall received during crop season. The state is endowed with a wide variety of soils viz., red and laterites (66 %), black (25 %), alluvial ( 5 %) and coastal ( 3 %) soils. Though crop production is carried out on all of them, these soils have varied potentials due to inherent fertility and limitations because of soil based problems. Though suitable technologies have been developed to overcome them, indications are there to show that many farmers in dryland areas are not adopting them. Several soil fertility surveys carried out in the state show that the soils, in general, are low in available N, low to medium in available P and medium to high in available K. The changes occurred in fertility indices with respect to soil organic carbon was analyzed over the past two decades. The data showed high status of organic carbon in soils of East and West Godavari districts. The changes occurred in fertility indices of soil organic carbon can be attributed to the changes in land use as agrisilvi culture system which showed the highest content of organic carbon, application of manures such as vermi compost being superior to poultry manure, biogas slurry etc. and incorporation of crop residues in soil. Incorporation of pre kharif legume green manures in rice fields was also significantly influencing the soil organic carbon status even showing residual effects on subsequent non rice crops 11

12 like groundnut and sesamum. Application of powdered groundnut shells was found equally good as that of application of 5 t ha -1 under groundnut mono cropping conditions. The available N status of soils of Andhra Pradesh is low and strategies have been developed for its management in rice and other crops grown in the state under different situations. Split application of N is the best way of supplying N to all the crops. The available P status is low in most of the cases and application of sources containing P is needed for obtaining higher yields. While placement of P fertilizers is important for all the crops, broadcast application proved to be better for rice than others. To ensure proper supply of K, 20 to 60 kg K 2 O is recommended through MOP or SOP depending upon the crop and soil while S needs can be met through application of 30 to 60 kg S ha -1 through ammonium sulphate, gypsum etc. Zinc deficiencies in soils and crops are wide spread followed by Fe while deficiencies of Ca, Mg, Mn, Cu and B are rare. Deficiencies of Mo are observed in acid soils of Srikakulam and Vizianagaram districts. The corrective measures have been suggested to farmers for overcoming these problems. Microbiological investigations carried out indicated the beneficial effects of Rhizobium on crops like soybean, blackgram, greengram, redgram, Bengalgram and subabul. Azolla incorporation at 10 t ha -1 is suggested for rice crop. Other bio fertilizers like PSB, PSM and VAM are useful for extracting P from soil by maize, Bengalgram etc. Based on the results of studies carried out through out the state on INM, suitable combinations of organic manures, inorganic fertilizers and bio fertilizers were suggested for different crops and cropping systems. Options were also made available to farmers based on their economic conditions for mesta based systems. As the recommendations made for the crops grown under irrigated conditions may not be suitable to dryland agriculture, green leaf manuring, application of cop wastes generated from mixed and inter cropped legumes etc. are suggested. Application of inorganic fertilizers to certain crops based on STCR and targeted yield equations were also furnished. The technologies generated for problem soils, results on avoiding sub soil salinity through drainage pipes laid out, avoiding pollution caused due to irrigation with industrial effluents and overcoming soil physical problems were also reviewed. Very few studies were carried out on the soil moisture to indicate its support to crop growth specifically in drought prone areas of the state. The data generated by NBSS & LUP, Nagpur on available water capacity and soil water balance are furnished in tables and figures, respectively. The effects of soil management on water availability period, results on models of groundnut yields through soil moisture status at 30, 60 and 90 DAS, effects of tillage induced soil physical conditions on soil moisture regimes, influence of application of PVA on soil moisture status in profiles etc. involving different crops were reviewed. Regarding the current status of soil management by farmers in dryland areas, the observations were furnished for individual mandal/district while an overall analysis was also given for the entire dryland area in which the Projects of BIRDS are in operation through the Partner NGOs. The farmers are not aware of soil organic carbon status, soil moisture content to support crop growth etc. as such analyses were not carried out elaborately in their districts. They may be advised on getting soils and waters tested, following the INM practices to economize the usage of commercial fertilizers, use of bio fertilizers suitable for different crops, adopting soil and water conservation practices etc. 12

13 Current Status of Soil Management in Andhra Pradesh 1. Introduction Soil is the most basic and vital natural resource on which agricultural production depends. Maintenance of soil fertility and productivity is a real key to achieve sustainability in agriculture. Andhra Pradesh is primarily an agrarian state and it is one of the progressive states in agricultural development in the Country sustaining a very high level of crop production. However, it has wide variations in its climate and soils.there is considerable area under dryland agriculture, which is drought prone. The coastal region is highly productive and is under cultivation of low land rice and several commercial and fruit crops. But this area also suffers from the cyclones and floods caused by excess rains. Recent surveys carried out indicate that the crop production is suffering due to problems in soils and inefficient management of inputs. Several technologies have been developed for adoption by farmers of the state. These include the maintenance of soil fertility using manures, fertilizers and bio fertilizers, managing physically problematic soils, amelioration of salt affected soils, avoiding soil pollution problems etc. developed by several local, national and International institutes present in the state. However, it is also noticed that these technologies either are not reaching the farmers or not being adopted by them even to date. There is a need to make the farmers aware of the relevant technologies suiting their farming situations and practice them to realize higher income from their holdings in the context of adverse effects of climate change in recent years. An effort is now made towards this direction of knowing the current status of soil management at farmers level and documenting the recent developments in efficient management of soils by reviewing the available literature to educate the farmers on judicious management of their resources. 2. Background As indicated above, the State of Andhra Pradesh is endowed with good fertile soils but the rainfall Is highly variable. An analysis of 40 years data indicates that the mean annual rainfall varies from 540 mm in Anantapur district to 1211 mm in Srikakulam district. In general, the dryland districts of Rayalaseema receive an annual rainfall of 500 to 900 mm, lowest being at Anantapur while the highest is in Chittoor district. The distribution of rainfall in the state as a whole is about 68 percent during South West monsoon ( June to September), 22 percent during North East monsoon ( October to December) and the rest is received during winter and summer months. Among the other dryland districts, Prakasam, Mahabubnagar and Nalgonda receive mean annual rainfall of 780 mm, 770 mm and 753 mm, respect tively. At times, these districts even face droughts frequently making the life of rural communities miserable due to failure of crops, lack of fodder to animals etc. The land degradation is hastened thereby, the vulnerability of those living there to climate change is on increase. The dry land farmers are therefore, resource poor, do not adopt the technologies generated 13

14 if they are costly and are insensitive to effects of climate change specifically in managing their soils and inputs. Keeping in consideration the facts mentioned above, the Bharati Integrated Rural Development Society (BIRDS) decided to make efforts to reverse environmental degradation and poverty of rural people through adaptation to climate change in drought stricken dryland districts of Andhra Pradesh concentrating in 9 hydrological units covering an area of 134,442 ha over a period of 3 years for the benefit of a population of 204,567 living in 123 habitations. It obtained financial support from Global Environment Facility (GEF) and FAO of United Nations. It involved 9 NGOs Viz., CARE, CARVE, DIPA, GVS, PARTNER, SAFE, SAID, SYA besides its own field unit at Allagadda in Kurnool district as Partners for executing the project entitled Strategic Pilot on Adaptation to Comate Change (SPACC) in the area of operation. 3. Objectives of the project The following are the main objectives of the SPACC project: To increase the knowledge and capacity of communities to adapt to climate variability and change in 7 drought-prone (Prakasam, Anantapur, Kadapa, Kurnool, Chittoor, Mahabubnagar and Nalgonda) districts of Andhra Pradesh, To contribute to the knowledge building and experiences in integrating climate change adaptation in sustainable land and water management (SLWM) in drought prone areas, and To help building the skills and tools for the communities to integrate climate adaptation in SLWM practices and their decision making. 4. Methodology adopted The project has 3 main components as furnished below: Collection of information tools for decision making and development of local institutional capacity, Conducting pilots on adaptation measures to be integrated into SLWM, and Providing a platform for scaling up climate change adaptation measures suitable for drought prone areas. These components are expected to enable farmers and community based organizations make decisions on land and water management based on scientific and local knowledge taking into consideration the impacts of climate variability and change, acquire required skills in managing climate risks through participation in climate change schools, identify best practices and adaptation of technologies and practices demonstrated through pilots conducted, besides documenting the packages of best adaptation tools and practices by the Project management and disseminate them for scaling up. 14

15 In line with the objectives and expected outcomes of the Project, it was decided to document the current status of soil management in Andhra Pradesh and review the technologies developed to manage the manures, fertilizers, bio fertilizers etc. A Proforma was developed to get the information on different aspects of soil management specifically in the 7 dryland districts, where BIRDS Project is implemented. The information was gathered by contacting at the rate of 15 farmers in 9 mandals ( Ramasamudram in Chittoor, Kasinayana in Kadapa, Rudravaram in Kurnool, Uppunuthala in Mahabubnagar, Tiparthy in Nalgonda, and Ardhaveedu, Cumbhum, Markapur and Racharla mandals in Prakasam districts) and 17 farmers in Gooty mandal of Anantapur district. The responses were compiled and observations made from data of each of the districts were separately given. An overall compilation of the data to get idea on status of management of soils and inputs like fertilizers etc. was also given in Appendices II to IX. A few suggestions were made in conclusion given at the end for BIRDS to take necessary steps in conducting pilots, organizing climate schools etc. 5. Andhra Pradesh State Andhra Pradesh is the fifth largest state in India occupying an area of million hectares. It is divided into 3 regions viz., Coastal Andhra (9 districts), Rayalaseema (4 districts) and Telangana (10 districts). It is one of the agriculturally potential states of the country with million hectares (46.5 per cent of the total area) put to a wide variety of agricultural and horticultural crops. Physiographically, the state has land forms as plain land including rugged plains, hills, isolated hillocks, dykes, uplands, rolling areas and flat land. It has 3 major river basins (Krishna, Godavari and Pennar) and five minor ones besides a long coast line of 972 km facing the Bay of Bengal on the East. The coastal plains occur at an altitude ranging from m above MSL (35 per cent of the total area) and have the best agricultural lands of the State. The Peninsular plateau has altitude ranges of 150 to 600 m above MSL while the Eastern Ghats have the altitude ranges of > 600 m above MSL, constituting 52 and 13 per cent of the total area, respectively. The State represents a transition from tropical to subtropical India with the climate predominantly arid to semi arid, except coastal region which has humid to sub humid climate. It is estimated that nearly 65 percent of the cultivated area falls under dryland agriculture while the rest is irrigated. It is considered as rice granary producing 16 to 18 percent of the country s rice in only 10 percent of the total rice area of the country. Apart from rice, the major food crops include sorghum, pearl millet, maize, finger millet and pulses. Groundnut, cotton, sugarcane, castor, gingelly, chillies and tobacco constitute the important non food crops. The state is also occupying predominant position in live-stock wealth with cattle, sheep and goats maintained by farmers. It has the largest poultry population of the country and also large scale aquaculture practiced by farmers demanding adequate production of feed stocks. The State has been divided into seven agro-climatic (viz., Krishna-Godavari, North Coastal, Southern, Northern Telangana, Southern Telangana, Scarce Rainfall and High altitude and Tribal) Zones ( Figure -1). The range of rainfall usually received, land forms existing, soils occurring and major crops and cropping systems grown in these Zones are furnished in table-1. 15

16 16 Figure-1: Agro-climatic zones of Andhra Pradesh Adil aba d Nizam bad Karim nagar Med ak Ranga Reddy Mahbub nagar Kurn ool Anant apur Chitt oor Cudd apah Nell ore Kham mam Nalg ond a Praka sam Gun tur Kris hna Wes t God avar i East Goda vari Visha kapat nam Vizia nagar am Srikaku lam Waran gal

17 Table-1 : Description of Agro-climatic Zones of Andhra Pradesh S. N o. Zones Rain-fall (mm) Land form (with elevation) Soils Major crops grown Predominant cropping systems 1. Krishna- Godavari (Delta) Zone Delta and valley lands plains river hinter River valley and delta alluvial soils, mixed red and black and deep black soils in sub coastal valley Rice, cotton, black gram/ green gram, groundnut, fodder, tobacco, sugarcane, chillies, coconut, sesamum Rice based 2. North- Coastal zone Coastal plain and isolated hill ranges, delta and several smaller rivers (0-300 m) Coastal alluvium patches below lateritic and red sandy uplands Rice, groundnut, pearl millet, mesta, finger millet, sugarcane, sesamum, horse gram, green gram, black gram Rice, sugarcane, groundnut, pearl millet and finger millet based 3. Southern zone Coastal plain and Southern part of central hill ranges, delta Pennar and catchment of smaller rivers (0-900 m) Coastal alluvium belt below lateritic and red sandy hinterlands Rice, groundnut, sorghum, pearlmillet, redgram, finger millet, horse gram Rice and groundnut based 4. Northern Telangana zone Deccan plateau and valley low lands, Godavari catchment area ( m) Mixed red and black soils and medium black soils and plateau, deep black soils in Sorghum, rice, maize, cotton, groundnut, redgram, and Bengalgram Sorghum, rice and maize based 17

18 valleys and red sandy soils in uplands 5. Southern Telangana zone Deccan plateau and hill range catchment of Krishna river ( m) Red sandy soils and medium black and lateritic soils Sorghum, rice, castor, groundnut, pearlmillet, red gram, horsegram, finger millet, greengram, maize, safflower Sorghum, rice and castor based 6. Scarce rainfall zone Deccan plateau and hill ranges and valley low lands, catchment of Pennar river ( m and ranges to >1000 m) Red sandy soils in uplands and mixed red and black to deep black soils in lower areas Groundnut, sorghum, setaria, rice, cotton, coriander, pearlmillet Groundnut, sorghum, setaria, rice and cotton based 7. High altitude tribal area zone Mountains, isolated valleys and foot hills, catchment of several smaller rivers ( m) Rice, pearl millet, groundnut, finger millet, sesamum, tuber crops, forest trees and horticultural crops Rice and pearlmillet based Several Institutions located in Andhra Pradesh have contributed to the information on aspects related to geology, water resources, climatic conditions and, soils and their management during the past several decades. However, the local Acharya N.G. Ranga Agricultural University (ANGRAU) contributed most through its net work of Research Stations spread over the entire state with the involvement of staff and P.G. students. The other Institutes like International Crops Research Institute for Semi Arid Tropics (ICRISAT), Central Research Institute for Dryland Agriculture (CRIDA), National Remote Sensing Centre (NRSC), National Geophysical Research Institute (NGRI), Survey of India (SOI), Directorate of Rice Research (DRR). Directorate of Oilseeds Research (DOR), National Bureau of Soil Survey and Land Use Planning and geology and soils divisions of traditional universities viz., Andhra, 18

19 Osmania and Sri Venkateswara Universities before the ANGRAU was formed,contributed knowledge on understanding and management of soils for improving their productivity and realizing higher yields from crops through appropriate technologies developed in different agro-climatic zones of the state. All these have been reviewed under different subheads. 6. Soils of Andhra Pradesh The State is endowed with a wide variety of soils having less fertile coastal sands to highly fertile and productive deltaic alluviums of major river basins developed from different parent materials. The major soil groups are red and laterite, black, alluvial and coastal soils occupying 66, 25, 5 and 3 per cent of the total area, respectively (Raman et al.,1985). The places of occurrence of these major soils in different districts of Andhra Pradesh( Venkateswarlu,2001) are given below (Table-2) : The salient characteristics of all these soils along with their constraints, which require management interventions are presented below: 6.1. Red soils The red soils include red sandy soils (Dubbas and coarse chalkas), red earth with loamy subsoil (medium and fine chalkas) red loamy soils (shallow to moderately deep), red loamy soils deep to very deep and red soils with clayey sub soils. These soils are in general, rapidly to moderately permeable with good drainage conditions. Soils are neutral in reaction (ph 6.5 to 7.5) and non saline. The clay minerals consist of a mixture of kaolinite and illite with low to medium Cation Exchange Capacity (CEC). They are prone to erosion Red sandy soils These coarse soils have an effective depth ranging from 20 to 60 cm indicating that they are shallow to moderately deep. The ph of the soils varies from 6.5 to 7.5 and these are non saline. The soils are rapidly permeable with intensive leaching exhibited under heavy irrigation or high intensity rain fall conditions. The clay content is usually < 15 per cent. These soils have low base exchange capacity and are poor in fertility Red earths These soils show a loamy or clay sub soils. The soils with the former usually exhibit ph ranging from 6.5 to 7.5 and occur on the elevated regions nearer to hills, hill ranges and on sloping terrains. These are non saline and have low CEC. The surface drainage is good to excessive. The soils vary in depth ranging from as low as 8 to 75 cm (shallow to moderately deep). The red earths with clayey subsoil show rapid permeability at surface while the subsoil is moderately permeable. ph of these soils is ranging from 6.5 to 8.0 and these soils show more CEC than the ones with loamy sub soil. The effective depth of these soils ranges from 30 to 75 cm. 19

20 Table-2: Major soils of Andhra Pradesh and their distribution Major soil Soil types Places (Districts) of occurrence Red soils Red sandy loams ( Alfisols, Entisols, Inceptisols) Parts of Ranga Reddy, Medak, Guntur, Prakasam, Nellore and Kurnool Red earths (Alfisols, Telangana region, parts of Rayalaseema and Nellore Inceptisols) Red loamy soils - Shallow Parts of Kadapa, Anantapur, Chittoor and Nellore to medium ( Alfisols and Entisols) Red loamy soils - Deep Parts of Khammam, Krishna and Guntur (Alfisols) Red soils with clay base Deep (Alfisols) Srikakulam, Vizianagaram, Visakhapatnam, Parts of East Godavari and West Godavari Laterites Laterites (Oxisols) Kavali taluk of Nellore, Zaheerabad Mandal of Medak and very small pockets in Visakhapatnam, Srikakulam and West Godavari Black soils cotton Black soils - Moderately deep to deep (Vertisols and Inceptisols) Black soils-deep (Vertisols) Parts of Adilabad, Nizamabad, Karimnagar, Warangal, Khammam, Medak, Ranga Reddy, Mahabubnagar, Kurnool, Anantapur, Nellore and Guntur Major areas in parts of Kadapa, Anantapur, Kurnool, Mahabubnagar, Guntur, Prakasam, Krishna, Khammam, and Nellore districts : small areas in Warangal, Adilabad and Nizamabad Parts of East and West Godavari, Krishna and Guntur Deltaic Deltaic alluvial soils( alluviums Entisols and Vertisols) Coastal soils Coastal sands (Entisols) Along the coast in Visakhapatnam, East and West Godavari, Krishna, Guntur,Prakasam and Nellore Salt affected Saline soils Occur in large areas in coastal districts of Nellore, East soils and West Godavari, Visakhapatnam and Srikakulam besides Prakasam, Guntur and Krishna Saline - alkali soils and Among coastal districts, Anantapur, Kurnool and parts alkali soils of Telangana districts in localized patches Red loamy soils Based on depth, these soils are shallow to moderately deep red loamy soils and deep to very deep red loamy soils. The former usually have depth ranging from cm and occur where the area was subjected to severe erosion. The surface coarse texture favor easy drainage while the subsoil is denser tending to show more clay with depth. The latter category exhibits variation in drainage viz., well drainage with light textured sub soil and moderately well to well drainage with clayey subsoil. The effective depth of the former category of soils will be over 125 cm while that of latter category ranges from 110 to 200 cm. While the ph of shallow to moderately deep soils varies from 7.0 to

21 ,the deep to very deep soils show the ph values of 6.0 to 7.2. These soils generally exhibit low base exchange capacity Laterite soils Laterite soils are deep (0.9 to 1.8 m) to very deep (> 1.8 m), medium to fine textured with clay subsoil and rapidly permeable and well drained. These soils are formed under conditions of high rainfall with alternate wetting and drying period. The leaching of the bases leads to development of soil acidity with soil reaction (ph ) values as low as 4.0 to 5.0, in a general ph range of 4.0 to 6.0. Soils are non saline. The soils have very low CEC and,hence, are poor in fertility. Taxonomically, these soils belong to the order Alfisols and association of Entisols, Inceptisols and Alfisols whereas the laterite soils are Oxisols Black Soils These soils have a local name as regur. Deep black soils (Vertisols) have high clay content (30-60 per cent or more) and, hence, are slowly permeable and ill drained. They exhibit an effective depth of over 180 cm. The ph ranges between 8.0 to 9.0. These soils are usually non saline at surface but salt content increases with depth. The soils exhibit high base exchange capacity due to high clay content. Moderately deep soils are loamy to clay loamy with clay sub soil, moderately drained, neutral to moderately alkaline in reaction (ph 7.0 to 8.5), non saline but have higher salt content than red soils. These soils are also having similar fertility characteristics as above. The soils exhibit calcareous nature containing high amounts of free lime, which occurs as nodules of varying sizes in depths of cm. Structural variations are seen ranging from sub angular blocky to prismatic depending upon the drainage conditions existing in the profile. They contain montmorillonite clay mineral and high CEC. Sheet and rill erosions are seen in these soils Deltaic alluvium These soils occurring in major river deltas have finer fraction ranging from 60 to 70 per cent. They are very deep (> 1.8 m) and lack of profile development. Drainage is a main constraint in these soils. Water table occurs within 5 cm depth coming up to ground level in basins. These soils are neutral to alkaline (ph 7.0 to 9.0) and marginal to highly saline. Clay mineral composition shows wide variations. The CEC of soils is usually high and, hence, they are productive. Taxonomically, these are Entisols and Vertisols Coastal soils These are very deep (1.8 to 5.0 m and above), coarse textured with sandy sub soil, belonging to the order Entisols. The soils are rapidly permeable, neutral in reaction (ph 6.5 to 7.5) with sub soil salinity due to shallow water table and low CEC due to very low clay contents. 21

22 6.6 Salt affected soils It is estimated that about 1 per cent of the total area of the state is under the problem soils like saline, saline-alkali and non saline alkali soils mainly occurring along the sea coast, streams and are usually interspersed in black, red and alluvial soils Saline soils These soils occupy considerable area in coastal districts of the state with salts contents exceeding even 0.2 per cent reaching a high concentration of even more than 4.0 per cent. The soils have low Exchangeable Sodium Percentage (ESP) of less than 15. The ph is around 7.0 and seldom goes beyond 8.5.The high water table can cause moist conditions at the surface Saline - alkali soils These soils are also occurring in the coastal districts and in some hinterland areas along the stream sides. The ph ranges from 8.0 to 10.0 while the salt content was found ranging from 0.3 to 1.5 per cent or even above. The water table is usually shallow showing not only high salt contents but also the presence of alkali carbonates Non saline alkali soils Though the ph values are similar to the above category, the salt content generally is low. The ESP values exceed 15.These soils have poor physical conditions and exhibit even water logging due to dispersion of clay clogging the pores. Though depending upon the salt content, the saline soils can be of some fertility value, the other two categories exhibit poor fertility and physical conditions affecting the crop production seriously. Management of these soils requires implementation of technologies generated so far specific to the given type of problem soil to improve its productivity. A recent survey (1996) carried out by National Bureau of Soil Survey and Land Use Planning (NBSS & LUP), Nagpur in cooperation with the State Department of Agriculture (SDA), Andhra Pradesh helped to categorize soils based on soil test values as follows: Salinity levels: Non saline (89.2%); Slightly saline(7.3%); Moderately saline ( 0.1%); Strongly saline ( 13%) ; Strongly sodicity (1.2%) Calcareousness: Non calcareous (64%); Slightly calcareous (10%); Moderately calcareous (18%) Soil reaction (ph): Strongly acidic (1.1%);Medium acidic (2.2%); Slightly acidic (7.6 %); Neutral (26.8%) 22

23 Mildly alkaline ( 23.6 %); Moderately alkaline (31.4 %) Strongly alkaline ( 6.2 %) Rock land and other miscellaneous land (8%) (Values given in parenthesis indicate the extent of area under each category). In spite of variations in fertility levels, these soils are supporting the production of a wide range of field, horticultural, plantation crops etc.(table-3) with the management of manures and fertilizers etc. under different agro-ecological situations not only making the state the rice bowl but also agriculturally important through commercial production of several commodities of export value. Table-3 : Area, production and productivity of principal crops in Andhra Pradesh ( and ) Crop Area( lakh ha) Production ( lakh tonnes) Productivity ( kgha -1 ) Rice Jowar Maize Bajra Ragi Wheat Redgram Greengram Blackgram Bengalgram Horsegram Groundnut Sesamum Castor Sunflower Safflower Soybean Cotton Mesta Sugarcane (cane) (cane) Tobacco Chilli Source: Directorate of Economics & Statistics, A.P. The seasonal conditions during were not encouraging as the state received only 659 mm of rainfall against a normal of 845 mm. The productivity of all crops except bajra, wheat, horsegram, groundnut and mesta decreased compared to previous year. The seasonal conditions 23

24 during , on the other hand, were satisfactory as the average rainfall received was 1227 mm against normal rainfall of 940 mm. There was increase in production of rice, maize, bajra, wheat, redgram, greengram, groundnut, sesamum, castor, safflower, soybean, cotton, mesta and sugarcane compared to last year. Though there is no change in area sown, the maize crop showed tremendous change in productivity besides castor, soybean and sugarcane during Under good seasonal conditions, even the fertilizer responsiveness will also be better as nutrient use efficiency is also dependent on soil moisture status. In view of this, the productivity can be higher than the year with bad conditions. 7. Surveys for assessing soil fertility status Nutrient surveys were carried out throughout the state for the purposes of identifying the status of different nutrient elements in soils and in plant composition besides knowing the constraints existing in soils, which are coming in the way of successful crop production. In East Godavari district, the low land rice soils were found medium to high in organic carbon, medium in phosphate and high in available potash. In West Godavari district, the soils were mostly high in organic carbon, low to medium in available phosphate and high in available potash. The oil palm growing soils of this district also exhibited deficiencies of Zn (33 %) and Fe (6 %). In Chittoor district, the available P and K in rice soils were low to medium and medium to high, respectively. The available S content was found low in these soils. However, in a separate survey, 150 groundnut and sunflower growing soils were collected and examined for their S status. The results showed that 62 per and 38 per cent soils were low and medium in S supply, respectively. In the S. V. Cooperative Sugar Factory area of this district, the clay soils showed the available N contents in the range of low to medium while available P and K contents were in the ranges of medium to high. Significantly highest contents of all the nutrients were found in clayey soils followed by sandy clay loams, except for P, which was found in high amounts in sandy loam and silty loam soils. In groundnut growing soils of Anantapur district, almost all the soils were low in N while they were deficient in available P, S, Zn and Fe to the extent of 16, 62, 81 and 23 percent, respectively. The betel vine growing areas in Andhra Pradesh, in general, have soils with varied texture (sandy loam to clayey) and moderate acidity to extreme alkaline conditions. They are low to high in available N, low to high in available P 2 O 5 and medium to high in available K 2 O. In lateritic and black soils, the available S was also found to be low. For these gardens in Krishna district, where the betel vines are showing differences only in Fe content, application of lime to correct the condition of excess Na and very high Residual Sodium Carbonates ( RSC) and rotation with crops like maize, groundnut etc. were advocated. The groundnut growing soils in Guntur and Prakasam districts indicated the need for the addition of P, K, Mg and Zn to coastal sands and P, Zn and Fe to other soils for achieving high productivity of the crop( Riazuddin et al.,2004). The black and red soils existing in NSP right command 24

25 area of these two districts showed the problems of alkalinity and calcareousness affecting the yields of pulse crops due to lime induced Fe chlorosis. However, no soil problems were noticed in chillies growing area of Guntur district. The declining conditions of sweet orange orchards in Anantapur and Prakasam districts were attributed to the presence of compact layers in profile and high clay content at subsurface level, which causes the problem of impeded drainage. High ph, contents of soluble salts and calcium carbonate besides low organic carbon also contributed to the decline in yields of the crop grown in these orchards. In chillies growing Warangal district soils, low to medium organic carbon, low available N, medium to high available P and low to high available K status were reported. In this Northern Telangana Zone, the turmeric growing districts of Nizamabad, Adilabad and Karimnagar belonging to Inceptisols (sandy clay loam to clay loams) were low to medium in available N and P and high in available potash. In Nalgonda district, the acid lime is cultivated in orchards having calcareous soils, which are having deficiencies of Zn and Fe to the extent of 91 and 36 percent, respectively. In Warangal and Karimangar districts, the sweet orange is extensively grown on Ustochrepts, which are low in available N, P, Zn and Fe and medium to high in available K. Among 74 soils collected from the sunflower growing areas in Scarce Rainfall Zone, deficiencies of N and P were observed to the extent of 49 and 22 per cent, respectively. Even S, Zn and Cu were found to be limiting in these soils. In cotton crop, lime induced Fe and Zn deficiencies were noticed in the medium to deep Vertisols. Besides these, B and Zn induced P deficiencies were also noticed in the crop. The chickpea grown soils were found to be deficient in N, P and Zn. The lime induced Fe deficiency was noticed in sunflower crop too. In the Southern Zone, the sweet orange orchards are having soils varying from sandy loam to clay in texture. They were low to medium in available N, low to high available P 2 O 5 and medium in available K 2 O.The available Zn content was below the critical level in most of the soils. The acid lime grown Nellore district soils were found to be deficient in Mg besides Zn, Fe and Mn. Some sweet orange gardens were also showing Zn deficiency problem in the crop. All these observations bring out the need for external application of the required nutrients in sufficient quantities through appropriate sources following the packages for agricultural and horticultural crops recommended in the state. Soils of Andhra Pradesh are, in general, low to medium in organic carbon, low in available P and medium to high in available K. Though the soil organic carbon content is estimated by the State Soil Testing Laboratories (STLs) as an alternative to know the status of available nitrogen in soils, determining its status is important as it influences positively the soil physical properties such as color, texture, density, pore space, and water holding capacity besides supplying other nutrients such as P, K, S, Zn and B as well as CEC, adsorption of pesticides etc. 25

26 8. Status and management of soil organic carbon The organic carbon contents of <0.5%, 0.5 to 0.75% and > 0.75% are considered as low, medium and high, respectively for deciding its status in soils. According to NBSS & LUP, Nagpur 56.7, 27.2 and 14.2 per cent of total area in the state belong to low,medium and high categories, respectively( Reddy et al., 1996). However, there are no specific attempts made so far to study in a systematic manner about the nature and content of soil organic matter in soils of Andhra Pradesh. A survey of available literature, specifically the theses submitted by Post Graduate students to Acharya N. G. Ranga Agricultural University, shows that the organic carbon estimations were carried out as part of other studies only. An early study carried out on representative soils of the state indicated that 45 percent of Coastal Andhra districts, 62 percent of soils of Rayalaseema districts and 52 percent of the soils of Telangana districts were low to medium in soil organic matter ( Kumar Sastry and Mathur,1972). Low to medium status in Vertisols of Kurnool district was reported by Srinivasa Rao (1987). In Telugu Ganga Project area, low contents were reported in Chittoor (0.096 to %) and Nellore districts. However, Padmavathi (1988) observed the organic carbon contents of 0.30 to 0.99 percent in the latter district. The organic carbon contents varied from 0.16 to 0.72 per cent in rice growing soils and to percent in groundnut growing soils of Chittoor district. In another study, Vijaya Shankara Babu (1989) found the organic carbon contents of 0.25 to 0.49 percent in Alfisols, 0.39 to 0.67 percent in Vertisols and 0.30 to 0.63 percent in Inceptisols of Chittoor district. Vijaymohan Reddy (1989) reported slightly higher contents of 0.30 to 0.75 percent in Alfisols of this district. In sugarcane growing fields of Chittoor district, Sreenivas (1989) observed the organic carbon contents of 0.20 to 0.60 percent. Hoang (1991) observed 37 percent of soils as high, 42 percent as medium and 9 percent as low in organic carbon contents in Nalgonda and Khammam districts. Among Vertisols collected from 12 districts of Andhra Pradesh, Surekha ( 1991) reported the soil organic carbon contents of 0.14 to 0.74 percent in surface soils. Sai Ram (1992) collected 56 calcareous soils ( Black soils 38 ; Red soils - 18) from different mandals of Guntur, Kurnool and Mahabubnagar districts and reported the ranges of organic carbon as to per cent ( mean of %) in black and to percent (mean of %) in red soils indicating their generally low status. Seetharama Sharma (1992) reported the organic carbon contents of 0.30 to 0.68 percent in saline soils collected from the coastal districts of the state. Padmaja (1994) found the soil organic carbon contents of 0.21 to 0.65 percent, 0.20 to 0.61 percent and 0.12 to 0.83 percent in soils of Ranga Reddy, Mahabubnagar and Medak districts of Andhra Pradesh, respectively. Uma Devi (1996) surveyed 141 red soils belonging to Anantapur, Srikakulam and Karimnagar for their sulphur status. These soils were found to have the organic carbon content ranges of to percent in Anantapur, to percent in Srikakulam and to per cent in Karimnagar with the mean values of 0.315,0.377 and percent, respectively. But for a few, most of them were showing low status with the overall mean of 0.39 percent only. Prabhu Prasadini and Singa Rao (1995) studied 15 profiles of Srikakulam district ( Inceptisols-6, Alfisols-4,Entisols-3 and Vertisols -2) for understanding the production constraints in those soils. The organic carbon contents ranged from 26

27 0.15 to 1.03 percent. Among these soils, 12 of them were found low and 2 were medium while only one was showing high status. Mesta growing soils of Srikaulam (156) were studied by Sreelatha (1998) for their nutrient status. Among these, 108 were sandy clay loams and 38 were sandy loams in texture. While 6 of them were clay loams and 4 were clayey in texture. According to her, most of the soils (68.4%) were low while 30.8 per cent were medium and only 1.3 percent were high in status of soil organic carbon. Studying the nitrogen and phosphorus availability indices in some rice growing soils of Andhra Pradesh, Laxminarayana (1998) noticed the range of soil organic carbon contents as to percent, with a mean of percent. Out of these, 20,11 and 1 soils were having high, medium and low status, respectively. Satyavathi (2001) surveyed 22 black and red soils of Experimental Stations of A.N.G.R. Agricultural University located in Telangana region. It was observed that the organic carbon status of red soils was ranging from 0.02 to 1.38 per cent. In most of the soils, the organic carbon content was decreasing with depth, while in only two profiles, it was showing an increase with depth. However, no systematic pattern of distribution was also noticed in some of the profiles studied. Aariff Khan (2001) noticed the organic carbon content ranges of 0.11 to 0.38 percent in young and 0.09 to 0.38 per cent in old orchards; the mean values being and percent,respectively. Thirty one rice growing deltaic alluvial soils of West Godavari (17 clayey,sandy clay and sandy clay loam soils) and East Godavari districts ( 14 clayey and sandy clay loam to sandy loam soils) were having organic carbon contents of 4.70 to 6.60 g kg -1 ( mean of 6.06 g kg -1 ) and 5.50 to 6.70g kg -1 ( mean of 6.35 g kg -1 ), respectively (Veeraiah,2003). Lalitha Kumari (2005) noticed the organic carbon contents ranging from 2.40 to 6.66 g kg -1 ; mean being 4.09 g kg -1 in fifty ( Black-35, mixed black-6 and sandy loam-9) soils of chilli growing areas in Guntur district. In a few studies being taken up in soils of Anantapur, the ranges of organic carbon contents were seen as 0.29 (control) to 0.39 percent ( Half recommended dose + either application of FYM or groundnut shells at 4 t ha -1 ) with similar non significant changes under the influence of dikes, cluster sowing and intercropping with redgram. However, under the influence of organic farming, the soil organic carbon content was found double ( 0.45 %) against inorganic farming (0.22 %) conditions. In a survey carried out, the following observations were made (Agricultural Research Station, Anantapur ) on the fields of Agricultural Research Station, and farmers fields having red and black soils (Table- 4): Table-4: Status of soil organic carbon in and around the fields of Agricultural Research Station, Anantapur Particulars Soil organic carbon content (%) Range Mean Agricultural Research Station fields Farmers fields Red soils do- - Black soils Apart from these, in chilli growing soils of Warangal district, the organic carbon contents ranged from 0.2 to 1.05 per cent whereas in Typic Ustochrepts of Northern Telangana zone on which sweet orange is grown, it varied from 0.21 to 0.62 percent. In some soils of Northern Telangana 27

28 Zone, the organic carbon contents were found varying from 0.11 to 0.45 percent. Thus, in general, in majority of the cases, the soil organic carbon status was found very low to low, with a few belonging to medium and high categories. The state Government carries out the analysis of soil organic carbon in its Soil Testing Laboratories distributed all over the state and report district wise information based on fertility indices worked out and indicates the ratings as low (< 1.66),medium ( ) and high ( > 2.33). However, the method adopted by the STLs gives a qualitative estimation of soil organic carbon and there is a need to estimate it quantitatively for the given field or area to know the content accurately before specific studies are carried out on them. The data on number of soil samples analyzed based on which the fertility indices were worked out for soil organic carbon and others by the State Soil Testing Laboratories (STLs) for individual districts ( SDA, ) are furnished below (Table-5) : Table-5 : District wise data on soil samples analyzed by STLs ( ) S. No. Place / District Soil samples analyzed No. of samples showing status Low Medium High 1 Srikakulam Vizianagaram Visakhapatnam East Godavari West Godavari Krishna Guntur Prakasam Nellore Kurnool Anantapur Kadapa Chittoor Nizamabad Medak Warangal Karimnagar Adilabad Ranga Reddy Mahabubnagar Nalgonda Khammam

29 In a compilation made earlier, the fertility indices for soil organic carbon were reported up to (Shantaram and Sreeramamurthy,1995).The changes occurred in the fertility indices of soil organic carbon during the past 6 years against the previous reported values of can be seen in the following table-6: Table-6: Changes in fertility indices of soil organic carbon in different districts S. No. District Prior to Variations in status of soil organic carbon Mean (Past 6 yrs) Srikakulam Vizianagaram Visakhapanam East Godavari West Godavari Krishna Guntur Prakasam Nellore Chittoor Kadapa Anantapur Kurnool Ranga Reddy Nizamabad Medak Mahabub nagar 18 Nalgonda Warangal Khammam Karimnagar Adilabad There is a built up in soil organic carbon status in East and West Godavari districts while no change occurred in soils of Nizamabad district. Depletion is seen in most of the Telangana districts. Out of 22 districts, 15 districts were showing low contents in while a built up was seen during the previous years. Reasons for this change need to be investigated for maintaining the status in soils for normal crop production purposes. 29

30 8.1 Influence of land use systems on status of soil organic carbon Different land use systems viz., silvi agriculture, agri-horticulture, silvi pastoral, silviculture, pastoral and agriculture with reference to fallow land were studied for nutrient profiles. The results showed that all the land use systems had higher organic carbon contents in the surface layer than in the fallow land. Soils under silviculture showed the organic carbon contents of 0.94 and 0.84 per cent in upper and lower layers, respectively. Silviculture, silvi - pastoral,and silvi - agriculture systems showed higher organic carbon contents in surface than in the sub surface layer. Silvi culture, agri - horticulture, silvi - agriculture and silvi - pastoral systems showed higher organic carbon contents than fallow land in the sub surface layers. Soils under silvi agriculture, silvi pasture and silvicultural systems had higher available N than agriculture, pasture and fallow lands in surface layer. Under silviculture and agri-horticulture, soils showed higher soil quality index of 8. Among the land use systems studied, silviculture reversed land degradation at a faster rate. Properties of rain fed Alfisols put to alternate land use systems viz., fallow land, agricultural land, agri- horti system, silvi-pasture, agri-silvi-horti system, E. cameldulensis, L. leucocephala, A.albida, A. indica and T. grandis were studied. Highest organic carbon content of 0.90 per cent was observed under agri- horti system followed by silvi- pasture system ( 0.76 %). Lowest organic carbon content was observed in fallow land ( 0.18% ). The organic carbon content decreased with depth. In another study, soils under different land use systems were evaluated for soil organic carbon status and carbon utilization potential in improving soil fertility. Analysis of soils showed highest organic carbon status in agri-silvi culture systems ( 0.89% ) followed by silviculture ( 0.76% ). Fallow land showed the lowest organic carbon content of 0.18 per cent. The carbon mitigation potential of agri-silviculture ( 4.23 ) was maximum followed by silvi pasture (3.71), agri-silvi horti system (3.42), L. leucocephala (3.23) with the rest showing values < 3.0 when fallow land C-mitigation potential was assumed as 1.0. The decomposition rate (CO 2 release) was highest with A. lebback followed by L. leucocephala, A. albida and E. cameldulensis. Superior decomposition rate was found essential when substrate incorporation was in higher quantities. 8.2 Influence of manures on status of soil organic carbon Preparation of composts using earthworms and evaluation of different organic manures and grain legumes for improving soil fertility were attempted Earthworm population dynamics and vermi composting Dynamics of earthworm populations in sugarcane soils of Chittoor and Nellore districts were studied. Earthworm populations were not recorded in the months of May but gradually increased; the highest being observed in September with a decline up to February. Significant positive correlations of earthworm populations with fungi, bacteria, actinomycetes and soil respiration were observed. Soil moisture was most important factor in determining earthworm activity in soils. The population and weight of earthworms were highest in pressmud treatments followed by the cane 30

31 trash and bagasse. fruit waste, vegetable waste, sububul (L. leucocephala) leaves and mixture of all these, being succulent and soft in nature were vermi composted at a faster rate within one month. Sugarcane bagasse and sorghum stover, which have wide C : N ratio and huge quantities of lignin took 45 days for complete decomposition. Mixed feed vermi compost was superior to the rest and its C : N ratio was reduced to 14:1. Analysis of this showed N, P 2 O 5, K 2 O, Ca and Mg contents of 2.40, 2.10, 0.63, 1.19 and 0.55 percent, respectively. Total Fe, Zn, Mn and Cu contents were 0.7 percent, 520, 475 and 108 ppm, respectively. During the period of vermi composting, COD, C:N ratio and organic carbon contents were found reduced substantially and the decrease was more in vermi composted urban and farm wastes. A rapid decrease in these parameters was observed during the first 60 days and later stabilized by the end of 90 days. The vermi compost had a better plant nutrient status than traditional compost and helped in ensuring better germination and better crop stand with early vigor Evaluation of organic manures The improvement in soil properties due to application of organic manures followed the order: Vermi compost > Poultry manure> biogas slurry > Farm yard manure and these were found superior to the application of recommended dose of N besides control. In rice (Prasanna), the grain and straw yields followed the order: Azolla > gliricidia > poultry manure > farm yard manure > biogas slurry. The N uptake was also highest with Azolla and gliricidia treatments. Poultry manure at 0.05 percent organic carbon level applied along with 10 ppm of Fe, and 5 ppm Zn was the best combination for increasing the yield of maize. Decrease in Cu content was noticed when the organic carbon level was increased to 0.5 percent Evaluation of green manures in rice based systems Rice yields (grain and straw) were significantly influenced on incorporation of pre kharif legume green manures (sunhemp, dhaincha, green gram and cow pea ) and all of them were equally efficient irrespective of their varied N content and contribution to soil. In this long term experiment, the results obtained in the 5 th year conformed that pre-kharif green manured plots were superior to fallow plots and gave, on an average,33 percent higher grain yield. Dual use greengram emerged out as a candidate crop by virtue of being equal in stepping up rice yields over the other 3 sole green manure crops besides giving a yield of 475 kg grain ha -1. The dual use greengram yielded 563 kg ha -1 of grain additionally besides leaving behind 18.8 t ha -1 of crop residues for incorporation before rice transplanting. Fast growing sole green manure like dhaincha and sunhemp obviously gave higher amounts of biomass. Based on estimates, it was found out that these green manures contributed at least a minimum of 50 kg N ha -1. Uptake of N,P,K and Zn increased due to incorporation of legume green manures ( Table-7). 31

32 Table-7 : Beneficial effects of pre-kharif sole /dual use legume green manures on kharif rice Green manures Biomass Grain yield Rice grain yield N uptake (t ha -1 ) (kg ha -1 ) (t ha -1 ) (kg ha -1 ) Dhaincha Sunhemp Cowpea Greengram Fallow CD (0.05) CV (%) However, no significant influence of pre kharif legume green manures applied to rice was seen on the yields and uptake of rabi crop that was following rice. While In sunflower involved systems there was a negative balance, a positive nutrient balance was observed in other systems. The results further indicated that greengram-rice-groundnut system gave maximum cash returns without affecting soil fertility. However, nutrient reserves were found higher with dhaincha-rice-groundnut system. The greengram and cowpea, despite their lower biomass,were as effective as high yielding dhaincha and sunhemp on succeeding rice in terms of grain yield. However, with regard to N uptake, sole green manures recorded significantly higher N accumulation without reflecting in grain yield. This is plausibly due to slow and gradual release of N on account of lignin present in these plants having attained maturity at 60 days. In so far as their effects on rabi non-rice crops is concerned, sunflower and blackgram crops were not in any way influenced while yields of groundnut and seasmum crops differed significantly (Table-8). 32

33 Table-8: Residual effects of pre-kharif green manures on yield and N uptake of rice based rabi crops Green manure Groundnut Sunflower Sesame Blackgram crops Fallow Greengram Cowpea Sunhemp Dhaincha CD (0.05) 1.28 NS 0.54 NS CV (%) Both the crops recorded the maximum yields in dhaincha received plots. This was attributed to improved soil structure observed in these plots. Dhaincha with higher biomass contributed to better soil aggregation as indicated by higher percentage of soil aggregates > 0.25 mm (mean value of 60.44) than others Crop residue management An IRRI-DRR collaborative study was initiated during kharif, 1998 to evaluate the long term effects of different crop residue management treatments on yield and soil quality in rice followed by rice cultivation systems ( Directorate of Rice Research, ). During both the kharif, 2000 (4 th consecutive crop) and rabi, (5 th crop), grain yields were significantly highest in all the entire straw treated plots ((T 1-100% straw incorporation from pervious crop,t 3-100% straw + green manure in kharif and only with residual effect in rabi and T 4-100% straw burning over the control (T 5 ) and half of the straw incorporation treatment (T 2 ) as shown in the following table-9. 33

34 Table-9: Grain and straw yields and important soil parameters in long term studies on crop residues management Grain yield (kgha -1 ) Straw yield (kgha -1 ) Soil bulk Organic Available Kharif Rabi Kharif Rabi density carbon K 2 O Treatments (g cm -3 ) (%) (kg ha -1 ) T T T T T 5 Control CD (0.05) NS CV (%) The enhanced yield observed was due to favorable increase in various yield components. Crop residue incorporation through successive crop seasons also had favorable impact on soil characteristics like bulk density, organic carbon content and available K 2 O. Thus, these studies have brought out significant and positive effects of crop residue management treatments with or without the green manure on grain yield and soil characteristics beginning with the third crop season. In Southern Zone, different organic manures ( Sheep manure, vermi compost, gingelly, sun hemp as green manures and pongamia and neem as green leaf manures to supply 20 kg N ha -1 ) applied to Oriental tobacco grown on sandy loam soil did not show any influence on soil physical and physico - chemical properties of the soil. However, organic carbon status was significantly increased due to application of these manures. Besides this, significant increase in N content was observed over control when sunhemp and vermi compost were applied. Neem, gingelly and vermi compost applications also resulted in higher K content in soil than others. Sunhemp was found better in increasing the micronutrient status of soil, green leaf yield and cured leaf yield. 34

35 8.3. Groundnut production system at Anantapur Long term ( ) cropping, fertilization, manuring ( groundnut shells, FYM) and INM practices improved the soil organic carbon in a groundnut mono cropping system under arid conditions in Alfisols. Carbon build up and organic carbon sequestration rate was higher with the addition of FYM and crushed groundnut shells along with 50% RDF. Groundnut shell application was found equally good as FYM treatment and in some cases it was better than FYM application in terms of pod yields and carbon build up in the soil. Thus, regular additions of locally available groundnut shells or FYM along with inorganic fertilizers can maintain or improve soil organic carbon stocks even under arid conditions (Srinivasa Rao et al.,2009).in the permanent trial conducted on groundnut grown on a shallow Alfisol, Maruthi Sankar (2010) reported a range of 0.13 to 0.69 per cent for soil organic carbon.the mean soil organic carbon value over the entire duration indicated the range as 0.23 to 0.38 percent; the maximum being observed in the treatment with50 % N kg Nha -1 ) and in farmers practice ( 5 t ha -1 ). 9. Management of nutrients 9.1. Nitrogen Available nitrogen can be determined by an accurate and popularly known alkaline permanganate method. The available nitrogen contents of < 280, and > 560 kg ha 1 obtained by this method are considered as low, medium and high, respectively for soil test rating purposes. This method though accurate, is time consuming. As already indicated, the organic carbon method is usually followed by STLs. Regarding the status of available N, 57 percent of the soils in the state fall under low category while 27 and 14 percent of the soils fall under medium and high categories, respectively. This suggests the need for application of N to crops through organic and inorganic sources. Only soils of the areas under dense forests show high contents of N. Nitrogen is present in soil both in inorganic and organic forms. Inorganic N occurs in soils as N 2 O, NO, NO 2 and NH 3 which give rise to NH 4 +, NO - 2 and NO - 3 ions. The contents of different forms vary with the type of soil. In Andhra Pradesh, Vertisols (black soils) have higher contents of NH N than Alfisols (red soils). On the other hand, Alfisols have more NO 3 - N than Vertisols. In general, Vertisols showed 35.0 to 87.5 mg kg 1 NH 4 + -N and 14.0 to 45.5 mg kg 1 NO 3 -N while the Alfisols had 28.0 to 70.0 mg kg 1 NH 4 + -N and 21.0 to 94.5 mg kg -1 NO 3 - -N. In coastal rice soils, NH 4 + is present in higher amounts in black followed by alluvial and laterite soils. Black soils fix more ammonium than red soils. A positive correlation between the amount of NH 4 + fixed and organic matter content was also reported. Inorganic materials like clay minerals specifically illite and vermiculite fix NH 4 + form of N in soils Management of fertilizer N a) Rice: Among the crops grown in Andhra Pradesh, rice is exhaustively studied with respect to its N nutrition. Several studies were aimed at finding out the effect of sources, methods and times of N 35

36 application on performance of this crop besides for assessing possible residual effects of applied N on subsequent crops (Sreenivasa Raju and Narasimham,1995). Rice requires adequate supply of N at tillering and flowering stages. Out of the total N absorbed up to flowering, 50 to 60 per cent is transported for grain formation. A plant content of 3 percent N is necessary at initial tillering for higher yield at harvest. Rice varieties differ significantly in their responses to applied N. Rice varieties Tellahamsa, Mahsuri, RP 4-14 and MTU-8002 during kharif and Tellahamsa, Rajendra, Sona and RP 4-14 during rabi gave responses even up to 120 kg N ha -1 on a Vertisol of Hyderabad. However, rice varieties SLO-13 and Jagannath grown on clay soils of Guntur required only 40 and 80 kg N ha -1, respectively. Thus, N is recommended to rice at as low as 40 kg ha 1 to as high as 120 kg ha -1 depending upon the seasons in coastal Andhra districts. A dose of 80 to 100 kg N ha 1 is suggested for Rayalaseema and Telangana districts. Sources of nitrogen have considerable influence on performance of rice as it is grown under low land conditions where reduced conditions exist, which influence its availability and enhance N losses of several types. Sodium nitrate was found inferior to ammonium sulphate, ammonium nitrates and urea in Vertisols of Hyderabad. Placement of N as USG (1g size) at a dose of 80 kg ha -1 resulted in higher dry matter yield and N uptake. Sulphur coated urea and USG were found more efficient due to slow releasing of N from them. Application of N in splits is advantageous over its full basal application especially in light textured soils. Split application of N at kg N ha 1 or in 3 splits of equal proportion at planting, maximum tillering and panicle initiation stages resulted in maximum grain yield in sandy loam and alluvial soils at Hyderabad and Maruteru, respectively. However, at Tirupati for direct seeded Sona rice (IET 1991) grown on sandy loam soil, application of N in 2 splits at 50 kg N ha -1 each at tillering and panicle initiation stages was recommended. Nitrogen applied through foliar sprays was also found beneficial and was absorbed more by young leaves followed by stems and older leaves. b) Other cereals: Responses up to 120 kg N ha -1 were observed in case of wheat while maize showed responses even up to 180 kg N ha -1. Sorghum requires 40 and 80 kg N ha -1 on Alfisols and Vertisols, respectively. Bajra requires N at 120 kg ha -1. However, in semi arid Alfisols and Vertisols, 40 and 80 kg ha -1 were recommended to this crop as in the case of sorghum. Ragi responds to N up to 90 kg ha -1 though lower doses of 60 to 75 kg N ha -1 were found optimum when grown on sandy clay soils. All these crops require N application in 2 to 3 splits for higher N use efficiency. c) Oilseed crops: At Tirupati, it was observed that the average fertilizer N requirement to produce one tonne of groundnut pods was 4.38 kg ha -1 and to obtain a pod yield of 33 q ha -1, the requirement was 20 kg N ha -1. Nitrogen application at 90 kg ha -1 in 2 splits viz. ½ as basal and ½ at 30 DAS or 1/3 basal and 2/3 as top dressing at 30 DAS was found to give higher seed yield and N uptake in sunflower crop. However, varieties like Morden require N at 60 kg ha -1 in 3 splits viz., 50% basal, 25% at button and 25% at flowering stages. Application of N at 40 kg ha 1 in 2 equal splits i.e. at sowing and at 25 DAS proved to be effective for castor grown at Palem. However, at Hyderabad, Aruna castor required 80 kg N ha -1 when dead furrows were formed at 1.5 m interval. d) Chillies Unlike other crops, application of N at recommended dose as single application is beneficial to chillies than its application in splits. For rainfed chillies, urea was found to be a better source of N than ammonium sulphate and groundnut cake. 36

37 e) Cotton Cotton yields in rice fallows can substantially be increased with N at 120 kg ha -1 under closer spacings of 60 X 45, 60 X 60 or 75 X 45 cm. f) Sugarcane At Anakapalle, sugarcane grown on loamy soils required and kg N ha -1 as yield maximizing and economic doses, respectively. Highest yields of cane and sugar were obtained when the recommended dose of N was applied in two equal halves at 45 and 90 days after planting. g) Mesta The fiber yield was maximum at 75 kg N ha -1 at which level the crop removed 75 kg N ha -1 from soil. Recovery of applied N ranged from 30 to 42 percent ; the rest being lost from soil. Some guidelines for efficient management of N in flooded rice using prilled urea finalized by the Directorate of Rice Research, Hyderabad are furnished below (Table-10) : Table-10: Nitrogen management strategies for low land rice crop under different situations Situation Assured water supply Soil very poor in N Permeable soils Short duration varieties Long duration varieties Colder growing season Overage seedlings used Danger of bacterial leaf blight (BLB) Strategy N can be top dressed every 3 weeks up to panicle initiation stage. Drain the field before top dressing and reflood after 2 days Give relatively more N at planting Emphasis is to be on more number of splits Prefer more N as basal: early top dressing is needed More number of top dressings are required Less N as basal and more N as top dressing More N is to be applied at planting More number of smaller splits of N have to be applied The management practices recommended for other crops based on their duration apart from the conditions of soil and climate existing in a given area are furnished below( Table- 11). 37

38 Residual effects of applied N Karanj cake mixed urea, mahua cake mixed urea and sulphur coated urea (SCU) applied at 100 kg N ha -1 to rice were more effective in producing wheat than when N was applied as urea in splits. Among these, karanj cake mixed urea application to rice resulted in more efficient utilization of N by the subsequent crop of wheat for grain formation. Table -11: Efficient management practices for N in ID crops grown in Andhra Pradesh Crop Management practice Maize Sorghum, pearl millet and finger millet Apply in 2 equal splits in heavy soils and in 3 splits in light soils (basal, knee high stage and flag leaf emergence) Apply N in 2 equal splits ½ at sowing and ½ as top dressing at knee-high stage of the crop. For rainfed crops, apply ¼ as basal and remaining ¾ after about a month of crop growth Pulses, groundnut and sesamum Castor Sunflower Hybrid cotton Mesta Sugarcane Eksali Adsali Apply all N as basal at seeding Apply in 2 splits ½ at sowing and the rest at DAS Apply in 2 splits ½ at sowing and the rest at DAS Apply N in 3 equal splits at 30, 60 and 90 DAS. For other cottons- in 2 equal splits at 30 and 60 DAS Apply in 2 splits basal and at 20 DAS Apply in 2 equal splits at 60 and 120 days after planting Apply in 3 equal splits at 60 and 120 and 180 days after planting Tobacco Apply in 3 splits viz., ¼ at 10 th day after planting, ½ at 3-4 weeks and the rest ¼ at 40 th day after planting Safflower and other rabi crops All N as basal at sowing by placing it deep 38

39 9.2. Phosphorus Like nitrogen, phosphorus is also present both in organic and inorganic forms in soils. Formation of different inorganic forms of P in soils depends upon factors such as parent material, soil ph, presence of free CaCO 3, contents of sesquioxides etc. Calcareous soils contain large quantities of calcium bound P. Among different forms of P, the occluded Fe-P content was largest in different surface (0-30 cm) soils of Guntur district. Next to this, Ca-P was predominant in alluvial and black soils. Organic P and Fe-P were higher in irrigated black and irrigated red soils, respectively while occluded Al-P and Fe-P were less than any other fractions in these soils. The contents of Al-P, Fe-P and Ca-P were reported as 14.0, 46.0 and 25.6 ppm in red (Alfisols) and 6.4, 60.5 and 66.6 ppm in black soils (Vertisols) of Hyderabad, respectively. In coastal alluvial soils, the predominance of different P fractions generally followed the order: Occluded Fe-P > Ca-P > org. P > Fe-P > occluded Al-P. The surface soils contain higher total P than the sub soils. The available P ranged from 0.8 to 11.7 kg ha -1 in NSP and from 1.2 to 16.8 kg ha -1 in SRS Project soils. Phosphorus recovery from the soils is influenced by high amounts of CaCO 3 and high ph. In both the cases, the P recovery is less. In soils having high organic matter, the availability of P was found higher at 40 o C than at room temperature. In calcareous regur soils of Telangana region put to rice, the applied P was found precipitated as Ca-P. Available P in normal and alkaline soils is extracted by Olsen s method while Bray s-1 and 2 reagents are used for acid soils. Contribution of Ca-P to Olsen s P was more than others in soils. In the state, 79.7, 16.5 and 2.1 percent of soils were found falling under low, medium and high categories, respectively for available P. Soils of Adilabad, Anantapur, Chittoor, Kadapa, East Godavari, Guntur, Hyderabad, Karimnagar, Khammam, Kurnool, Mahabubnagar, Medak, Nalgonda, Nizamabad, Prakasam and West Godavari districts are low in available (Olsen s P) while the soils of Krishna, Nellore, Srikakulam and Visakhapatnam are medium in available P status. None of the districts had soils with high P status. Crop plants exhibit preferences to different P fractions present in soils as shown in the table below (Table-12). Hence, knowledge of different P forms existing in the given soil will help to exploit them by growing appropriate crop. It also helps in reduction of external application of the sources containing this nutrient Management of fertilizer P Like scientists of any other State, effects of application of P fertilization on crops grown in Andhra Pradesh were extensively studied by many workers in Andhra Pradesh too (Sreenivasa Raju,2003). a) Rice Results of experiments and experiences on farmers fields indicated that rabi rice responds more to applied P than kharif rice. In West Godavari district, rice responded to the application of 50 kg P 2 O 5 ha -1 during kharif while rabi rice showed responses up to 100 kg P 2 O 5 ha 1. In general, application of 60 kg P 2 O 5 ha -1 was found optimum even though responses were observed even up to 120 kg P 2 O 5 ha -1 at Nandyal. 39

40 Table-12: Crop specificities for soil phosphorus fractions Crop Rice Wheat Sorghum Maize, cowpea Pearlmillet, Jute Redgram, blackgram, greengram, sunflower Groundnut Fractions of P taken in Fe P, Al P Ca P, Al P Adsorbed P Al P, Fe P Fe P Al P Ca P A critical level of 33.6 kg P 2 O 5 ha -1 was established for NSP soils below which rice needs fertilizer P application for producing economic yields. Critical levels of 18, 30 and 33 kg P 2 O 5 ha -1 were determined for red soils of Chittoor, deep black soils of Nizamabad and black soils of West Godavari districts, respectively. Based on the relationships worked out between P availability and clay content, the following formulae were given for judicious application of P after calculating the % P recovery: % P recovery : % clay ( for black soils) X % clay ( for red soils) X % Clay ( for alluvial soils) X % clay + % silt ( for laterite soils) Utilizing the Soil Test Crop Response (STCR) approach, experiments were conducted on rice, sugarcane, maize etc. and fertilizer P schedules for different agro-climatic regions at given targeted production levels were given in the form of ready reckoners for all the major nutrients. A few of them have been given under a separate sub head. b) Maize Responses of maize to application of P at 60 kg P 2 O 5 ha -1 were reported. However, combined application of 90 kg N and 60 kg P 2 O 5 ha -1 appears to be optimum for CM 119. c) Sorghum Maximum yield of sorghum was noticed at 80 kg P 2 O 5 ha -1 although hybrids like CSH-1 showed response even at 100 kg P 2 O 5 ha

41 d) Bajra In chalka soils, responses to applied P up to 40 kg P 2 O 5 ha -1 were reported though under greenhouse conditions application of 60 kg P 2 O 5 ha -1 resulted in maximum yield. e) Ragi f) Oilseed crops Under pot culture conditions, ragi responded to application of 30 kg P 2 O 5 ha -1 to soil. Application of 60 to 90 kg P 2 O 5 ha -1 were recommended to groundnut grown on chalka soils of Hyderabad. Low responses of castor to P application were reported, which were attributed to the slow growth and deep rooted nature of this crop. No significant responses were noticed when P was applied to safflower grown on red soils. Sunflower grown on chalka soils required 30 kg P 2 O 5 ha -1 for high yields. g) Pulse crops Blackgram responses up to 50 and 80 kg P 2 O 5 ha -1 were recorded when grown on sandy clay loam soils of Bapatla under field and pot culture conditions, respectively. However, applications of 30 and 60 kg P 2 O 5 ha -1 were found optimum when grown on chalka and black soils, respectively under greenhouse conditions. Similar to blackgram, greengram grown on chalka was also requiring 30 kg P 2 O 5 ha -1. Responses of pigeon pea to applied P were not noticed in case of Vertisols while responses up to 60 kg P 2 O 5 ha -1 were reported when grown on chalka soils having medium P content. Responses of cowpea and chickpea were noticed at 40 and 60 kg P 2 O 5 ha -1, respectively. h) Sugarcane Significant responses of sugarcane were reported up to 112 to 224 kg P 2 O 5 ha -1 in combination with high levels of N when grown on P deficient soils at Rudrur P-Utilization studies using tracer techniques Utilizing tracer techniques, several measures for improving fertilizer P use efficiency by crops were suggested. A few important results are given below: Phosphorus utilization by selected cereal, pulse and oilseed crops ranged from 7.6 to 13.5 at flowering and 8.4 to 20.7% at maturity. At harvest, the P utilization among the crops studied followed the order: Sunflower > ragi > bajra > black gram > groundnut > green gram. Sunflower crop is not only efficient in utilizing P from fertilizer but also is efficient in absorbing more P from native source. Tellahamsa, Mahsuri, RP-4-14 and MTU 8002 during kharif and Tellahamsa, Rajendra, Sona and RP 4-14 during rabi showed the per cent P derived from fertilizer (% Pdff) values 41

42 in that order. Application of N in combination with P also increased the % P utilization by these varieties. Tellahamsa, RP 4-14, Rajendra, Sona, MTU 8043 and Gowthama required a closer spacing of 15 X 10 cm whereas Mahsuri and RP did better in 15X15 cm spacing. Ammonium nitrates phosphates containing water soluble P ranging from 50 to 60 percent may be useful for rice grown on red sandy loam soils. For jowar grown on red and black soils, tri ammonium pyrophosphates and tetra ammonium pyrophosphates were found superior to others while for rice, tetra ammonium pyrophosphate proved to be better than others. For rice grown on chalkas and regurs analyzing low and medium available P 2 O 5, respectively, it was observed that P fertilizer can be top dressed at 15 days after transplanting when basal application couldn t be done. In case of low land rice, broadcast application of P in the last puddle was superior to its placement in black soils of Bapatla and Krishna Western Delta. Placement is the best method of P application for light irrigated and dry land crops. Rice seedling root dipping in phosphates or P solutions resulted in improved fertilizer use efficiency. There was a saving of 30 kg P 2 O 5 ha -1 by this technique of P application. Soaking of wheat seed in 1 or 2 % P solutions (KH 2 PO 4, DAP etc.) improved the P use efficiency by the crop Potassium The available K was low in a very small area (3%) in the state. In the rest of places, 40.4 percent fall under medium while 55.7 percent fall under high categories indicating that the soils are rich in available K status, requiring very limited application to only K loving crops. However, under highly leaching conditions and under intensive cropping, K is also becoming limiting nutrient and agricultural crops grown under these situations require application of K for growth, yield and quality of the produce. Depending upon the availability to crop plants, the inorganic soil K is classified into water soluble, exchangeable (both of which are immediately available to plants), fixed or non exchangeable ( which is held in the interlayer spaces of mica and layer silicate minerals) and lattice mineral bound K ( which serves as reserve). Potassium is also present in organic form. All these constitute the total K in soil. Among different forms of K, total and exchangeable K contents are higher in black soil while water soluble K is more in red soils. The amounts of total K were formed higher in coastal sands, red earths, red and alluvial soils while lower contents were recorded in black and laterite soils. Water soluble K, besides exchangeable and non exchangeable K, is more in sandy loams whereas lattice and total K forms are more in sandy clay loams. 42

43 Fixation of K is largely dependent on mineralogical composition of the soil to which it is applied. Since soils of Andhra Pradesh vary considerably in their mineralogical make up, they also vary in their K fixing capacity. Fixation of K by soils varied from as low as 3.7 percent in coastal sands to as high as 43.6 percent in black soils of Hyderabad. Available potassium is the readily available K which has both water soluble and exchangeable forms of K that can be extracted by different reagents. The available K extracted with NNNH 4 OAc showed significant positive relationship with crop uptake. The availability of water soluble and exchangeable K in red and black soils was found to increase at 40 o C and at 75 percent depletion of saturated moisture. The release of native K is found maximum under flooded conditions followed by saturation and dry conditions. Kinetic studies of K release from different fractions of soil K in different soil types indicated that the K release process from these soils is diffusion controlled exchange. The release rate constants worked out were larger for black soils (Kasireddipally series) than the red soils (Patancheru series). The availability of K is dependent on salient characteristics of soils viz., ph, OC, clay, silt contents etc. Water soluble, exchangeable and ammonium acetate exchangeable K contents were significantly correlated with silt fraction and organic carbon content in certain Alfisols of Ranga Reddy, Mahabubnagar and Medak districts. The review of PG theses indicated that the critical levels of K vary with soils for different crops grown on them (Table-13). Table-13: Critical levels of potassium in soils for different crops Forms of K Soil type/ area Crop Critical level Reference Available K Alluvial soils Bajra 160 ppm Sailakshmiswari (1984) Light soils of Sriram Rice 75 ppm Subba Rao et al. (1976) Sagar Project area Heavy black soils of Bajra & rice 95 to 100 Venkata Subbaiah et al. West Godavari ppm ( 1976) district Red soils of Ranga Reddy, Mahabubnagar and Nalgonda districts Tomato and brinjal 285 kg K 2 O ha -1 Padmaja & Sreenivasa Raju (1997) Exchangeable K Black soils Maize 0.25 me Surekha (1991) /100 g soil Water soluble K Clayey soils Rice Sarada (1988) me/100 g soil Non exchangeable K Light soils of Kodad Rice & groundnut 400 ppm 425 ppm Venkata Subbaiah et al.(1991) Black soils Maize 1.25 me Surekha (1991) /100 g soil Soils of Hyderabad, Sanga Reddy and Khammam Bajra 108 ppm Keshava Prasad (1981) 43

44 Management of fertilizer K a) Rice Response of rice crop to applied K was observed in some soils of Andhra Pradesh. Significant responses of Jaya rice (4.8 kg grain kg -1 K 2 O), were reported in Vertisols of Nandyal while in light soils of SRS Project area, the responses of 4.3 to 7.5 kg grain kg -1 K 2 O were noticed. At Tirupati, significant response of rice grown on sandy loamy soils to K applied at 40 kg K 2 O ha -1 as potassium schoenite was observed while in light textured soils of Kodada series, responses to applied K at 30 kg K 2 O ha -1 were observed on farmers fields. Studies carried out by Directorate of Rice Research, Rajendranagar also indicated that the grain yields of rice increased linearly with potash application. b) Maize In general, soils put to maize are moderate to high in K. However, consequent to high levels of N and P application without K, depletion of K occurs and the soil status comes down drastically affecting the yields. In order to avoid reduction in yields and to overcome the occurrence of stalk rots, regular dressing of K in balanced proportions are felt imperative to maize crop. c) Oilseed crops Groundnut removes large quantities of K from soil with the uptake ranging from 45 to 135 kg ha -1. It has been observed that the status of K in groundnut growing soils is gradually decreasing because of inadequate K fertilization. Responses of this crop were observed to K application when available K 2 O level was below 150 kg ha -1 requiring an application up to 40 kg K 2 O ha -1. Sunflower and mustard crops were also found to respond to K application due to their high K requirement. The K uptake among oilseed crops followed the order: sunflower > castor > niger > sesame. Sunflower yielding 3.5 t ha -1 removes 150 kg K 2 O ha -1. The K uptake was more in sunflower safflower, than in sunflower-castor, sunflower-groundnut, sunflower-sorghum and sunflower-pigeon pea sequences. d) Pulse crops Soybean and peas were found more responsive to K application due to their high K requirement. The K uptake among pulse crops follow the order: cowpea > pigeonpea > green gram > black gram > chick pea. At Lam (Guntur district), application of 20 kg K 2 O ha -1 improved the blackgram yields significantly (16.2 %) over control. e) Cotton Experiments conducted on cultivators fields indicated the need for balanced use of K against application of N or N P alone. The fertilizer recommendations range from 20 to 40 kg N, 20 to 40 kg P 2 O 5 and 0 to 40 kg K 2 O ha -1 for mungari (Desi) cotton, kg N, 20 to 45 kg P 2 O 5 and 20 to 45 kg K 2 O ha -1 for straight varieties and 100 to 120 kg N, 50 to 60 kg P 2 O 5 and 50 to 60 kg K 2 O ha -1 for hybrids, thus, emphasizing the need for application of K to all types of cotton. f) Sugarcane At Anakapalle, some varieties of sugarcane were found to respond to K application up to 100 kg K 2 O ha -1 as MOP and application of full dose at planting was superior to later applications. Ratoon 44

45 crops were also benefited by K fertilizer, more so when the preceding plant crop did not receive any K. Potassium application was found beneficial to rainfed crop helping it to overcome the drought at maturity phase. The critical level of available K 2 O in red sandy loam soils is determined as 250 kg K 2 O ha -1. The crop log studies indicate that a concentration of 2.0 percent has to be maintained in 3 to 6 sheaths throughout the growth period for realizing optimum cane and sugar yields. Though earlier varieties viz., Co 419 and Co 997 and Co did not show responses to K application, latest varieties like Co T 8201, 81A99, Co 7219 and 85A261 are showing responses to K application. Sugarcane is benefited by K applications as basal ranging from kg K 2 O ha -1 under irrigated conditions while ratoons respond up to 112 kg K 2 O ha -1. g) Chillies Chillies are grown on black soils, light textured chalka soils, sandy loams and loamy soils of Andhra Pradesh. Potassium requirement for production of one tonne of ripe fruits is 5.47 kg K 2 O in early cultivars while mid early varieties require 6.27 kg K 2 O. A potassium concentration of 3.5 percent in the 3 rd leaf of chillies at 70 days after transplanting is considered as critical limit below which yields are affected. Potassium application leads to improvement in quality of chillies. Application of 50 and 60 kg K 2 O ha -1 along with recommended doses of N and P is suggested for rainfed and irrigated crops, respectively. h) Other crops The crops like cashew, coconut, betel vine, oil palm and tapioca are cultivated in light sandy soils (Entisols) to intensively weathered laterites (Vertisols/Oxisols) through red (Alfisols) and black soils ( Vertisols) in Coastal districts. A positive correlation was observed between leaf K and Juice per cent and also ascorbic acid content of cashew. Application of K along with N and P also improved shelling per cent and kernel protein content. Application of 100 kg K 2 O ha 1 in deep black soils ( Vertisols) was found to significantly increase the growth of vine, yield of leaves and keeping quality of betel vine. For coconut, application of K as 2 kg along with N,P and FYM around palm in a trench between m distance from the trunk is recommended Response ratios for major nutrients The average response ratios at indicated levels of N, P 2 O 5 and K 2 O were 10.5, 4.5 and 4.5 at 120:60:60 for rice; 5.8, 3.0 and 3.4 at 90:60:30 for jowar; 3.0, 2.4 and 1.4 at 120:60:60 for ragi; 8.9, 5.1 and 4.9 at 120:60:60 for maize; 15.8, 1.5 and 0.6 at 20:40:30 for Bengal gram; 3.4, 2.4 and 0.6 at 60:60:20 for redgram; 27.6, 7.1 and 3.8 at 20:60:40 for groundnut; 1.9, 1.8 and 1.8 at 60:40:40 for gingelly; and for N and P 2 O and 2.1 at 20:40 for black gram; 12.1 and 2.7 at 20:40 for green gram and 19.8 and 1.4 at 20:40 for horsegram, respectively Calcium The average Ca content in the surface soils of groundnut growing area in Chittoor district was found ranging from 0.8 to 3.6 percent. The mean exchangeable Ca in these soils varied from 2.0 to 4.3 c mol (p+) kg -1 of soil. In Andhra Pradesh, soils of citrus and grape gardens of Nellore and Karimnagar districts were found deficient in Ca. The magnitude of exchangeable Ca was 5.6 and 21.8 c mol(p+)kg - 45

46 1 in red (Mahabubnagar) and black (Rajendranagar) soils, respectively. Calcium was found to positively correlate with pod yield in groundnut. When groundnut was applied Ca through gypsum, it was found to play a complimentary role in boosting the effect of applied S. Soil incorporation of 1 to 3 kg plant 1 is recommended to grape gardens grown in and around Hyderabad. In rice, the Ca concentration ranged from 0.2 to 0.5 percent; the critical concentration in leaves being 0.15 percent. Its absorption reaches peak stages at boot leaf and flowering stages. 9.5.Magnesium Though Mg content in lithosphere is estimated to about 2.1 percent, its average content in soils is only 0.5 percent ; the range being 0.1 to 1 percent in soils of India. The exchangeable Mg content in groundnut growing soils of Chittoor district ranged from 0.30 to 0.54 c mol (p+) kg -1 and its saturation on exchange complex varied from 7 to 15 percent. The content of Mg in groundnut plant samples ranged from 0.52 to 0.95 percent. The Mg content in cotton suffering from Mg deficiency was 0.2 percent, Citrus gardens of Nellore district showed 25 percent low, 37 percent medium and 38 percent high Mg concentrations in leaves. The Mg concentration in citrus plants in Karimnagar district ranged from 0.44 to 0.66 percent, with a mean of 0.56 percent. In general, soils which contain Mg < 1 me 100 g 1 soil or 4 to 15 percent of CEC occupied by Mg are treated as deficient in Mg. Magnesium deficiency in Andhra Pradesh was reported in soils of grapes, mango and citrus gardens besides cotton grown fields. In rice, Mg is absorbed maximum at boot leaf and flowering stages. Application of Mg was found to increase the concentration of Zn in groundnut and rice crops Sulphur Intensive agricultural practices including growing of crops and application of S free high analysis fertilizers besides ignoring application of organic manures to fields are causing quick depletion of soil S leading to wide spread soil and crop deficiencies. On an average, the alluvial soils were found to contain 1124, 32.2, 29.9 and 1096 ppm total S, 0.15% CaCl 2 extractable S, 0.01 M Ca (H 2 PO 4 ) 2 extractable S and organic S, respectively. The inorganic SO 4 -S contents were < 10 mg kg -1 in 17 percent, 10 to 20 mg kg -1 in 11 to 34 percent and > 20 mg kg 1 in 49 to 88 percent of soils analyzed. In soils of Prakasam and Guntur districts, total S and its organic S form occurred in large amounts in heavy textured (black) soils. In black soils of coastal Andhra Pradesh, the contents of different forms of S were: total S (660 to 2310 mg kg 1 ) > organic S (622 to 1266 mg kg 1 ) > inorganic, SO 4 -S (10.9 to 68.0 mg kg -1 ). The total S contents at different depths varied from 98 to 310 mg kg -1 in Alfisols and from 100 to 387 mg kg -1 in Vertisols. The inorganic SO 4 -S content ranged from 2.5 to 20.0 percent of the total S in these soils. Among various soil properties, organic carbon, total N and clay contents showed significant positive relationships with different forms of S in alluvial soils. In black soils, the clay significantly influenced total S (r = 0.477) and organic S ( r= 0.482) contents. The available S contents were ranging from 18.4 to 85.9 kg ha -1 and 12.3 to 81.5 kg ha -1 in coastal sands (Entisols) of Guntur and Prakasam districts, respectively. Sulphur from soil (SO 4 -S) is extracted using 0.15% CaCl 2 reagent, which was found superior to other extractants as well as microbiological method using Aspergillus niger (Sreenivasa Raju, 1997). Incubation studies indicated that the amount of S released was more at field capacity (37.3 mg kg -1 ) than at submergence (30.1 mg kg -1 ). The release of S was higher in Vertisols (38.2 mg kg -1 ) than 46

47 from Alfisols (36.5 mg kg -1 ). The pattern of S release gave an idea that the mineralization and immobilization processes were alternating with each other at some regular intervals. The S deficiency problems in soils are encountered in many districts of the state as detailed in table-14: Table -14 : Extent of S deficiency in soils of different districts Districts Extent of S deficiency ( %) Karimnagar > 60 Mahabubnagar, Nalgonda, Warangal, Khammam, Kurnool, Chittoor and Anantapur Nizamabad, Medak, Ranga Reddy, Kadapa, Nellore, Prakasam and East Godavari Guntur, Krishna, Srikakulam, West Godavari, Adilabad, Vizianagaram and Visakhapatnam < Management of fertilizer S The critical levels of S in groundnut crop were 0.20 percent in the whole plant and 0.23 percent in the leaves when grown on Alfisols of Anantapur district. Castor responded to application of S at 40 kg ha -1 through ammonium sulphate. However, application of S at 20 kg ha 1 was found beneficial to pulse crops such as cowpea, blackgram and greengram besides sesame crops. Among these crops, the fertilizer S uptake was higher with ammonium sulphate than with gypsum. However, the residual effects were found more with the latter than the former source. Under field conditions, mean S utilization values by sunflower crop at flowering were 3.24 percent, 2.26 percent and 1.12 percent with gypsum, K 2 SO 4 and SSP, respectively. Sunflower responded up to 60 kg S ha -1 in Alfisol while it responded up to 40 kg S ha -1 in Vertisol. Responses were highest with the sunflower genotype EC followed by APSH 11 and Morden when S was applied as ammonium sulphate. Bhendi fruit yields were found highest at 30 kg S ha -1 level applied as SOP. Application of S increased protein and oil contents in groundnut, and oil content in castor and sunflower crops. Removal of S was found highest with sunflower- safflower followed by sunflower-greengram and sunflower-sorghum systems both in Alfisols and Vertisols. The SO 4 = depletions in control plots were 17 percent in Vertisols and 64 percent in Alfisols. In Andhra Pradesh, application of gypsum in two splits of 250 kg ha 1 each as basal and at 30 DAS was found to increase the shelling percentage and yield of groundnut grown on Alfisols of Chittoor district. On Alfisols of Hyderabad, safflower (variety Manjira) showed highest yield with the application of S and P 2 O 5 at 40 kg ha -1 each. The economic dose worked out for this crop was 55.2 kg ha -1. Antagonism was observed between S and Mo in groundnut as increased application of S decreased the Mo content in soil as well as in groundnut plants. Since both these nutrients are being absorbed as anions (Mo0 4 = and SO 4 = ), they probably compete for the same absorption sites on the roots. 47

48 9.7. Micronutrients Zinc Mean available zinc (DTPA extractable) contents ranged from 0.59 to 2.04 mg kg 1 in soils of different districts of Andhra Pradesh. In more than 50 percent of the districts, more than 50 percent soils were found deficient in zinc. Among the soils, deficiency of Zn is highest in Vertisols and Alfisols (60 to 91%) followed by Inceptisols and Entisols. Extent of deficiency was 59 percent in Telangana, 54 percent in Rayalaseema and 45 percent in coastal regions of Andhra Pradesh. The critical levels of DTPA extractable Zn in soils varied from 0.6 to 1.0 mg kg -1 depending upon soil and test crop. The critical level for alluvial clay loams of Krishna district was 0.6 mg kg 1 while for highly calcareous alkaline soils of Karimnagar and Nizamabad, the critical level was 0.75 mg kg -1. The % recovery of added Zn can be calculated using the formulae: % recovery of added Zn = X (black soils) X (red soils) where X is % clay in the soil. The critical level of zinc in 3 rd leaf of rice varied from 8.3 to 10.0 mg kg -1. In maize, the critical concentration at the tasselling stage was 11.5 mg kg -1 under field conditions. The critical level of whole plant of sorghum at 60 DAS was 8 mg kg -1 while it varied from 16.0 to 21.3 mg kg -1 for groundnut. Crop nutritional surveys undertaken indicated that the Zn deficiency ranged from 2 to 85 percent, percent, 83 to 92 percent, percent and 55 to 65 percent in rice, citrus, mango, banana and turmeric crops, respectively. However, in sugarcane, the extent of deficiency was found negligible. The mean Zn concentrations in plant varied from 14.7 to 24.4, 11.0 to 15.5, 7.6 to 12.0 and 14.1 to 14.6 mg kg 1 in ground nut, citrus, mango and banana crops, respectively. The HYVs of rice are more prone to micronutrient deficiencies than locals. The relative susceptibility of rice varieties to zinc deficiency is as follows (Table-15): Table-15 : Tolerance levels of different rice varieties for Zn deficiency High Moderate Low Jaya Ratna Cauvery IR-8 Rajendra Tellahamsa RP S Sona Mahsuri In another study, the rice varieties M-7, MTU-1001 and Krishnahamsa were found to be highly susceptible to zinc deficiency and their performance was found better when grown on soils with high native Zn content or under conditions of external application. An overall response of rice varieties to the extent of 15.3 per cent over control was observed when Zn was 50 kg ZnSO 4 ha -1.The response was, however, more in long duration varieties (16.5 percent) followed by medium (15.9 per cent) and short duration (12.9 percent) varieties. 48

49 For light black sandy loamy soil, application of 50 kg ZnSO 4 ha -1 was found optimum (direct effect) and the residual effects lasted even after 4 residual crops; thus, indicating that the soils required zinc application after every 5 th crop. The P induced Zn deficiency symptoms were noticed when the tissue concentration of P was 0.28 percent and Zn concentration was 13.4 mg kg -1 with a P/Zn ratio of about Iron The mean DTPA extractable Fe in soils of different districts of Andhra Pradesh showed 4 to 7 folds variation; the minimum being 15 mg kg -1 in East Godavari district while the maximum of 71 mg kg 1 was observed in Karimnagar district. Under lowland conditions, Fe deficiency is not encountered while irrigated dry nurseries and rainfed rice grown on upland areas suffer from this problem. Groundnut also exhibits Fe deficiency specifically when the active iron content in leaf is < 10 mg kg -1. Fe deficiency to an extent of 19.9 percent was seen in mango orchards of Khammam district. Critical levels of 9.0, 10.0 and 5.0 mg kg -1 (DTPA extractable) Fe were determined in soils of NSP left canal area for maize, groundnut and sorghum, respectively. In a screening experiment on lime induced Fe chlorosis on groundnut varieties, it was observed that the yield reduction was less in TCGS-320 while others (TMV-2, TPT-1, TPT-2 and Vemana) showed reduction in yield with increase in CaCO 3 content in soils Manganese The manganese content in soils ranged from 8 ( Nizamabad district) to 120 mg kg 1 (West Godavari District). Manganese deficiency is not seen in rice. However, citrus crop of Nellore and Ananthapur districts exhibited Mn deficiency problem to the extent of 18.0 and 13.7 percent, respectively. Mango orchards in Chittoor district showed the Mn deficiency to an extent of 16.6 percent while excessive contents of 1500 mg kg 1 were recorded in banana grown in East Godavari district Copper The mean available Cu content was highest in soils of West Godavari district (13.3% mg kg -1 ) while it was least (1.2 mg kg 1 ) in light soils of Nalgonda district. The critical concentration of Cu in soil under NSP left canal area was 0.1 mg kg -1 (NN NH 4 OAc extractable) Boron Total B content in groundnut growing soils of Chittoor district ranged from 8.3 to 13.3 mgkg -1. Laterite soils of Andhra Pradesh contained available B contents ranging from 13.8 to 39.8 mg kg

50 Molybdenum In the high altitude areas of Srikakulam and Vizianagaram districts, the molybdenum deficiencies were noticed in the acid soils to the extent of 49 percent in the former and 45.7 percent in the latter. The extent of deficiencies of different micronutrients in the soils of Andhra Pradesh in comparison with soils of India are furnished in table -16(Sreenivasa Raju and Jeevan Rao,2004). Table-16 : Extent of micronutrient deficiencies in soils of Andhra Pradesh and India Place % samples deficient in Zn Cu Fe Mn B Mo Andhra 54 < Pradesh India Combined application of nutrients Nitrogen and phosphorus Rice soils of Andhra Pradesh were neutral in reaction and non saline in nature. The soils were low to medium in fertility status. Response of rice in these soils was high to applied N but was low to applied P. For parental lines of rice viz. IR-64, Tellahamsa, Rasi and Satya grown on sandy clay loam soils, combined application of 120 kg N ha -1 and 60 kg P 2 O 5 ha -1 was found optimum. IR 64 (44.69 q ha - 1 ) out yielded other parental lines followed by Satya (40.54 q ha -1 ), Tellahamsa (39.86 q ha -1 ) and Rasi (38.69 q ha -1 ). Increased P application was found to increase percent Pdff and this was also increased by N application. Root parameters and nutrient uptake were highest with application of 150 kg ha -1 and at 90 kg P 2 O 5 ha -1 to rice. The soil physical conditions were better under intermittent method of submerged conditions (I 2 ) than under continuous submergence (I 1 ). Mean grain yields of rice recorded under I 1 and I 2 were 4609 and 4284 kg ha -1, respectively. Application of 150 kg N ha -1 along with 120 kg P 2 O 5 ha -1 besides 50 kg K 2 O ha -1 resulted in a mean pod yield of 1641 kg ha -1, which was highest in case of chilli LCA 235 (Bhaskara) grown on black soil under rainfed conditions when 2 to 3 supplemental post monsoon irrigations to 0.45 m depth were given at an interval of 4 weeks. It was computed from the data that to produce one quintal of dry chilli pod,the quantities of 7.64 kg N and 1.11 kg P 2 O 5 were required with a water use efficiency of 2.16 kg/ ha mm

51 In soybean grown on sandy loam soil, application of 90 kg N ha -1 and 50 kg P 2 O 5 ha -1 resulted in highest seed yield, protein and oil contents and also highest uptake of nutrients. The oil content was decreased with increase in level of N while it increased with increase in level of P application. The contents of palmitic, stearic and oleic acids were found decreased with increase in level of N while the contents of linoleic and linolinic acids increased. A reverse trend was observed with P application to this crop. A few medicinal and aromatic plants were found requiring combined application of N and P. Ambrette (Abelmoschus moschatus Medic.) showed maximum dry matter and seed yield ( kg ha -1 ) when combined application of N at 150 kg ha -1 and P at 60 kg,p 2 O 5 ha -1 was done. However, this yield was on par with the dose 100 kg N ha kg P 2 O 5 ha -1 (559 kg ha -1 ) and, hence, this treatment was found economical. Similarly, senna (Cassia angustifolia Vehl.) grown on red sandy loam soil required combined application of 120 kg N ha -1 and 60 kg P 2 O 5 ha -1 to get highest herbage and pod yield. However, the Ocimum ( Ocimum basidum L.) showed maximum herbage production of 45.5 t ha -1 yielding 75.5 kg essential oil from main and ratoon due to combined application of 120 kg N ha kg P 2 O 5 ha Nitrogen and potassium In case of marigold (Tagetes erecta L.) grown on an Alfisol of Hyderabad, the dry matter production, concentrations of N, P and K and their uptake both at 60 DAT and harvest were increased with increasing levels of N and P application to the crop. Highest quantity of dry matter ( kg ha - 1 ), concentrations of N ( 2.16 %), P (0.9%) and K ( 1.5 %) and their uptake ( 200.4, and kg ha -1 for N, P and K, respectively ) were observed at 120 kg N ha -1 level. Similarly, all these parameters were found highest at 80 kg K 2 O ha -1. The flower yield ( q ha -1 ) and flower size ( 7.2 cm ) were also highest at the combined application of 120 kg N + 80 kg K 2 O per hectare. Though the highest carotenoid content of 3.54 mg g -1 was observed at the 80 kg N ha kg K 2 O ha -1, the effects of levels of N and K applications weren t found significant on this parameter. Hence, based on results, combined application of 120 kg N ha kg K 2 O ha -1 was recommended to marigold crop grown on Alfisols Nitrogen and sulphur Stalk and seed yields of sunflower (Morden) grown on an Alfisol were highest with the combined application of 100 kg N ha -1 and 60 kg S ha -1. The seed yield of 12.8 q ha -1 was recorded at a N:S ratio of 10.4 in the plant. In cabbage ( Golden acre) grown on a clay loam soil, application of 150 kg N ha kg S ha -1 gave the highest head yield of t ha -1 followed by 150 kg N ha kg S ha -1 (46.84 t ha -1 ). Increase in level of N application was found to increase S utilization while increase in level of S application decreased S utilization by cabbage. Highest seed yield of safflower was obtained with the combined application of 75 kg N ha kg S ha -1. However, from the response curve, the economic optimum levels of N and S found were and 55.2 kg ha -1, respectively. 51

52 Phosphorus and sulphur Castor crop grown on a red sandy loam soil medium in P (4.54 ppm) and low S (9.06 ppm) showed responses to both P and S applications showing increase in dry matter yields and yields of seed and stalk with increase in levels of application of these two nutrients. The mean seed yields recorded at maturity were 6.36 and 6.05 q ha -1 when DAP and SSP were the sources, respectively. The mean seed yields with sources of S viz. gypsum, SSP and ammonium sulphate were 6.68, 6.31 and 6.99 q ha -1, respectively. The levels of P and S also significantly influence P and S uptake parameters. The mean P utilization values of 2.93 and 8.61 per cent were recorded with DAP and 2.09 and 5.79 per cent with SSP at 45 and 90 DAS, respectively. Similarly, the mean S utilization values of 1.32 and 4.13 cent with gypsum, 1.01 and 2.69 per cent with SSP and 1.93 and 5.30 per cent with ammonium sulphate were recorded at 45 and 90 DAS, respectively. Castor indicated preference to Al-P as it depleted 57.3 per cent of this fraction in control plots. Significant effects of sources and levels of S were observed on oil content of castor seed while P application didn t show such effects. Sunflower grown on a sandy loam soil (Alfisol) having available N of kg ha -1, available P 2 O 5 of kg ha -1 and available S of 9.14 ppm showed highest seed and stalk yields, oil and protein contents and uptake of N,P,K and S due to the combined application of 60 kg P 2 O 5 ha -1 and 60 kg S ha - 1. Application of 50 kg P 2 O 5 ha kg S ha -1 was found economical to summer greengram while a dose of 40 kg P ha kg S ha -1 was required to safflower (Manjira) as it improved yield and P and S uptake by this crop Phosphorus and zinc Cauliflower grown on an Alfisol (available P kg P 2 O 5 ha -1 and available Zn ppm) required 100 kg P 2 O 5 ha kg Zn ha -1 as it gave optimum yield (245.4 q ha -1 ). At higher levels of 200 kg P 2 O 5 ha -1 and 40 kg Zn ha -1, antagonism was observed Nitrogen, phosphorus and potassium Nitrogen application up to 100 kg N ha -1 increased the pod yields of CA 960 (Sindhura) variety of chilli grown under rainfed conditions. The response was, however, highest at 50 kg N ha -1 level over control. Application P at 33.5 kg P 2 O 5 ha -1 and K at 50 kg K 2 O ha -1 was found beneficial as it improved dry matter production and nutrient uptake by chilli crop. Considering the main and interaction effects on yield and quality of the produce, application of 100 kg N ha -1, 75 kg P 2 O 5 ha -1 and 100 kg K 2 O ha -1 was recommended. It was also observed that for the production of 1 q dry pods, 1.9 kg N, 1.6 kg K, 1.0 kg Ca, 0.25 kg P, 0.15 kg Mg, 8.5 g Fe, 2.0 g Mn, 0.7 g Cu and 0.5 g Zn are required. Third leaf nutrient composition was found to show high correlation with nutrient uptake and total pod yields. The contents of N (3.4 to 3.5 per cent), P (0.38 per cent) and K (3.5 per cent) at 70 days in 3 rd leaf of chilli were regarded as critical values for CA 960 ( Sindhura ) under rainfed conditions. The nutrient uptake was found to increase up to 150 days (Harvest). Combined application of N,P and K showed pronounced influence on the vine growth. Maximum yield of 13.8 kg per vine was recorded with 225 g N g P g K in case of young 52

53 vines. In case of Thompson seedless grape, the combined application of 500 g each of N and P as DAP and 750 g K in the form of SOP gave maximum yield besides improving several quality parameters Nitrogen, phosphorus and sulphur Groundnut (TMV-2) grown on sandy loam soil at Hyderabad showed responses to applied N,P and S in terms of increase in dry matter content and uptake of nutrient (N,P and S), shelling percentage,oil and protein contents besides kernal yield. While the nodule number showed a decrease with increase in level of N application, the number increased with levels of P and S applications. Application of 40 kg N, 50 kg P 2 O 5 and 120 kg S ha -1 resulted in the highest kernal yield (15.43 q ha -1 ) of the crop with a shelling percentage of Combined application of micronutrients to horticultural crops i) Tomato Combined application of 12.5 kg ZnSO 4 ha -1 to soil along with foliar sprays of 0.2 percent ZnSO 4 and 0.5 per cent FeSO 4 thrice at later stages increased the fruit yields of brinjal and tomato grown on Alfisols of Southern Telangana Zone. ii) Grape A survey of grape gardens growing Anab-e-Shahi in and around Hyderabad showed that calcium, magnesium, zinc and manganese were deficient while the copper content was high. In order to overcome the deficiencies, the recommendations made were as follows: Calcium: Soil incorporation of 1 to 3 kg gypsum /plant per year Magnesium: Spray application of 1 % magnesium sulphate solution after each pruning Zinc : Soil application of ¼ kg zinc sulphate /plant per year OR spraying 0.05 %, 0.1% and 0.2 % zinc sulphate solution at 30,40 and 50 days after each pruning Manganese: Application of ¼ kg manganese sulphate per plant to soil per year OR foliar spraying of 0.2 % solution of manganese sulphate ( About 500 liters of spray fluid is required per acre for foliar application of nutrients.) Several nutrients were showing deficiency symptoms among crops grown on different soils of Andhra Pradesh. Certain corrective measures were suggested to overcome those deficiencies (Table - 17) Frontline demonstrations Several frontline demonstrations on sulphur and micronutrients were conducted in the state. Combined application of 5 kg Zn+40 kg Sha _1 resulted in 19.3 percent increase in yield of groundnut crop. The increase in pod yields of groundnut and blackgram were also witnessed due to the application of 5 kg Zn ( as zinc sulphate) and 40 kg S ha -1 ( through gypsum). In the latter crop, application of Zn 5 kg ha -1 along with kg ha -1 significantly increased the yield. In sunflower, maximum yield was obtained when treated with 2.5 kg Zn along with 20 kg S ha -1 and 1 kg B ha -1. Application of 2.5 kg Zn and 40 kg S ha -1 gave good economic returns in castor. 53

54 9.10. Microbiological studies Use of N bio fertilizers Micro organisms are involved in crop production as bio fertilizers mainly for two purposes viz., for fixing free nitrogen and making it available to higher plants and for distribution and mobilization of P and micronutrients for plant uptake. The potential for production of different bio fertilizers in ANGRAU and their distribution in 2004 ( Ramana reddy,2004) are furnished below (Table- 18) : Table-17: Crops exhibiting nutrient deficiencies and their corrective measures Nutrient Crops Corrective measures Phosphorus Groundnut, cotton, mesta, citrus and mango i) kg P ha -1 to red soils. ii) 35.0 kg P ha -1 to black soils iii) Bring the available P to 17.5 kg ha -1 taking P fixation into consideration. Potassium Groundnut Soil application of 41.7 kg K ha -1 if the soil test value is < 125 kg K 2 O ha -1 Calcium Citrus, vegetables, cotton, banana and mango i) 02 to 0.3 tonnes of lime ha -1 for acid soils ii) 0.5 tonnes of gypsum application to other soils( except saline and alkali soils) Foliar application of 1 % magnesium sulphate solution Magnesium Citrus, vegetables, cotton, mango and flowers Sulphur Groundnut 100 kg S ha -1 to groundnut and up to 50 kg ha -1 to other crops through any S containing fertilizer Zinc Rice, sorghum, maize, pearl millet, groundnut, cotton, mesta, citrus, grapes, sugarcane, cashew, mango,vegetables and flowers Copper Rice, cotton, citrus and cashew Iron Manganese Boron Rice, sorghum, pearl millet, groundnut, citrus, grape, sugarcane, flowers and cotton Rice, sorghum, pearl millet, banana, citrus, grape, sugarcane, flowers and cotton Cotton, mesta, citrus, and grape i) Soil application of 50 kg zinc sulphate ha -1 for normal soils ( once in 3 seasons) ii) Soil application of 25 kg zinc sulphate ha -1 in coarse textured soils iii) 2 to 3 sprays of 0.2 % zinc sulphate solution at weekly intervals in early stages of crop growth. i) Soil application of 25 kg copper sulphate ha -1 ii) Foliar application of 0.2 % copper sulphate solution at weekly intervals Spray application of 0.5 % ferrous sulphate solution ( repeat at weekly intervals till chlorosis disappears) i) Soil application of 50 g manganese sulphate ha- 1 ( 100 to 150 kg manganese sulphate ha -1 to alkali soils) ii) Spray application of 0.2 to 0.3 % manganese sulphate solution 2 to 3 times at weekly intervals. i) Soil application of 25 kg borax or boric acid ha -1 ii) Spray application of 0.1 to 0.2 % borax or boric acid solution twice at weekly intervals 54

55 An incubation study carried out showed the microbial immobilization of SO 4 -S in the initial stages while the peak mineralization was found to start from 30 days onwards in Alfisols and from 40 days onwards in Vertisols, reaching a plateau between 75 and 90 days in Alfisols and days in Vertisols. a) N fixing bacteria Rhizobium inoculation improved the growth, yield and nutrient uptake by groundnut while Azotobacter and Azospirillum inoculated were proved beneficial in sugarcane and sweet potato crops, respectively. In case of groundnut, Rhizobium was tried along with phytohormone precursors (L- tryptophan and adenine). Rhizobium inoculation at low levels of L-TRP increased the growth parameters, nutrient uptake besides available nutrient status. Adenine addition did not improve the growth parameters of the crop. The results indicated that Rhizobium plus L-TRP at 10-7 M concentration was beneficial to groundnut crop. The groundnut crop grown on red sandy loam soil was inoculated with Bradyrhizobium strain NC-92. This resulted in increase in nodule dry weight in the summer crop while pod yields of groundnut showed increase in all the seasons (kharif, rabi and summer). Inoculation and application of micro nutrients significantly increased concentration of N in the shoot tissue of summer crop and N and P uptake by kharif crop. Application of N at 20 and 30 kg ha -1 increased the nodulation compared to control in the rabi crop and increased dry weight in kharif and summer crops at 30 and 60 DAS. The N levels at 30,40 and 50 kg ha -1 increased N concentration and uptake in summer crop while application of 40 kg N ha 1 level resulted in increased P uptake and K and S concentrations in summer crop. b) Azolla Among azolla species studied, A. caroliniana and A. pinnata (R. Nagar) were found to produce highest biomass adopting to the local environmental conditions existing at Rajendranagar. Azolla was a good source of P and the amounts of micronutrients supplied were more than from other green manures crops. The yield and uptake of nutrients by rice was highest with azolla application at 10 t ha -1 level. However, highest yield of rice was obtained with the application of azolla at 10 t ha kg N ha -1. For optimum growth of the azolla species mentioned above, 20 kg P 2 O 5 ha -1 as SSP was found optimum. A. mexicana and A. microphylla were found tolerant to high salinity levels in soil. Application of K up to 150 ppm as K 2 SO 4 and 80 ppm Ca increased the biomass productivity of azolla grown on Alfisol. Azolla pinnata (Rajendranagar) responded better than Azolla pinnata (Cuttack). Level of Mg did not influence this parameter while S application up to 25 ppm level increased the biomass production. Hence, azolla needs to be applied K, Ca and S for increasing the N yield from the fern. Azolla application to field soil resulted in sufficient increase in availability of K up to 80 days though most of it decomposed by 60 days. 55

56 Table-18: Bio fertilizers produced and supplied by ANGRAU in 2004 Inoculant and crop No. of packets Population count (cells/q) Produced Supplied Rhizobium* Groundnut Soybean x 10 8 to 6.0 x 10 8 Blackgram x 10 8 to 4.8 x 10 9 Greengram x 10 8 to 5.4 x 10 9 Redgram x 10 8 to 6.2 x 10 8 Bengalgram x 10 8 to 6.3 x 10 8 Subabul x 10 8 to 5.7 x x 10 8 Azospirillum Sorghum, maize, bajra, paddy, sugarcane etc x 10 8 to 6.8 x 10 8 (200 g) (1.0 kg) PSB (250 g) 1150 (1.0 kg) x 10 8 to 5.4 x x 10 8 to 6.2 x 10 8 Rhizobium packets of 200 g each at a cost of Rs.7/- ; PSB Rs.7/- for 250 g + Rs.25/- for 1 kg packet ; Azospirillum Rs.30/- per packet of 100 g 56

57 c) P - bio fertilizers The treatment with P solubilizing micro organisms (PSM) increased the dry matter production, seed and haulm yields of greengram while P solubilizing bacteria (PSB) showed beneficial effects on sunflower grown on sandy clay loam soil under field and greenhouse conditions, respectively. The P- utilization by sunflower varied from 20.6 to 22.4 percent and 15.0 to 17.5 percent at flowering and maturity, respectively due to application of P at different levels. In the medium P soil, it was found possible to obtain similar P utilization even when recommended dose was reduced by 20 to 30 percent, inoculation was done and FYM was applied than that of application of 100 percent recommended dose of P alone. In a sandy clay loam soil with medium P (22.8 kg ha -1 ), maize (BH-1001) responded to application of rock 45 kg P 2 O 5 ha kg P 2 O 5 ha -1 along with PSM inoculation. Among P fractions, organic P and Ca-P contents showed more decrease in the inoculated treatments. Response of maize (DHM-105) to VAM alone was observed on a clay soil (Vertisol). The response was found more pronounced when VAM inoculation was done and P was applied at low levels of 30 kg P 2 O 5 ha -1. In a sandy loam soil (Alfisol) neutral in ph, low in available P and Zn but medium in available N, the mycorrhizae were found to establish well whether the soil was sterilized or not. Application of P was found to inhibit the growth of mycorrhizae while Zn application increased both the number of spores and infection on sorghum roots. The effects of mycorrhizal inoculation was more pronounced in sterilized soil than in unsterilized soil showing better dry matter production by sorghum, increase in content and uptake of P, K, Zn, Cu, Fe, and Mn by the crop. The available P, K, Zn, Cu, Fe and Mn contents in soil after crop harvest showed a decrease due to mycorrhizal inoculation indicating depletion of these nutrients due to better growth and uptake by sorghum crop than in inoculated soil. In Bengalgram (ICCV-2, Swetha) grown on a sandy clay loam soil, combined application of PSB + VAM and P applied at 50 percent recommended dose was found economical. Among the P fractions, organic-p and Ca-P decreased significantly while significant differences were not observed between inoculated and uninoculated in case of Fe-P, Al-P and occluded-p contents in soil. The phosphatase activities (acid and alkaline ) in rhizosphere were significantly increased with inoculation, P fertilization and by their interaction. d) Role of bio fertilizers In Andhra Pradesh, considerable work was carried out on role of Rhizobium in improving groundnut and pulse (chick pea and pigeon pea) yields. However, responses among crops due to Rhizobial inoculation are variable, inconsistent and are not as spectacular as that of chemical N fertilizers. This could be due to various reasons which include inadequacy of Rhizobial population, their effectiveness, host Rhizobial compatibility, environmental factors, physico-chemical properties and utilization of N 2 by plants to give the yield. Under dry land conditions, except cluster beans, no other legume was found to respond to Rhizobial inoculation. However, in Alfisols of Hyderabad, use of Azosrpirillum inoculation as seed dressing was found to increase the yields of sorghum and pearl 57

58 millet in dry land conditions. The effect was equivalent to 20 kg N ha -1. The studies of All India Coordinated Rice Improvement Project(AICRP) indicated no visible growth of blue green algae (BGA) in plots inoculated with the algal crust in any of the seasons tried. In view of this, it was interpreted that the climatic conditions are not suitable for its establishment and growth. Though growth of Azolla was also affected by similar reasons, applications of 6 t ha -1 green matter in combination with 25 kg N ha -1 as urea gave favourable results in rice during rabi season. At Maruteru and Nandyal, application of 10 t ha kg N ha -1 was found beneficial to transplanted rice. Studies with phosphate solubilizing bacteria indicated that Bacillus pulvifaciens can advantageously be employed in mineralizing and solubilizing P 2 O 5 contained in basic slag and bone meal in Alfisols and Vertisols and in the soils, which are near neutral to alkaline in reaction. The symbiotic association between plant roots and fungi, usually termed as mycorrhizal association, has been studied on crops like maize. It was found beneficial by solubilizing native P and its efficiency was found maximum at lower doses of applied P Microbial transformations in soils In a long term fertilizer experiment on rice (var. Tellahamsa), the organic carbon content was highest in treatment receiving 100 percent NPK in conjunction with FYM in which the available P status was also high. The grain and straw yields and uptake of N, P and K were also highest from soils. The contents of ammoniacal, nitrite and nitrate N were highest in the FYM treatment at 7 and 14 days of incubation. Significant positive relationships of organic carbon with NH 4 -N,NO 3 -N and NO 2 -N were observed Integrated Nutrient Management (INM) Andhra Pradesh is the second largest state as far as NPK consumption is concerned; UP being the first among states of India. In order to have sustainable agricultural production, matching with the population growth, INM appears to be the best option left out for soil fertility management in view of escalating cost of fertilizers and non availability of enough quantities of organic manures due to increased mechanization in recent years. Integrated nutrient management envisages the maintenance and possibly increase the soil fertility for sustaining increased crop productivity through optimizing all possible sources (organic and inorganic) of plant nutrients required for crop growth and quality in an integrated manner appropriate to each cropping system and farming situation in its ecological, social and economic possibilities. Integrated Nutrient Management has four important components viz., soil nutrient reserve, mineral fertilizer, bio fertilizer and organic manures which are integrated most appropriately in cropping systems. Studies on INM have been initiated in the past 15 to 20 years on individual crops, while cropping systems are taken into account during the past 10 years. The efforts made on this aspect are summarized below: Crops a) Rice Rice yields with the recommendation made by M/s PPIC (India Programme) i.e. 180 kg N kg P 2 O kg K 2 O per hectare were higher than with the state recommended dose of 120 kg N + 60 kg P 2 O K 2 O per hectare. Highest grain yield (7.53 t ha -1 ) was obtained with 50% N applied as 58

59 poultry manure (PM) + 50% RD of PPIC which, was on par with the same doses applied through FYM + fertilizer. Hence, application of 180 kg N kg P 2 O kg K 2 O per hectare + PM/FYM in 50:50 combination was recommended. In separate experiments, conjunctive use of FYM along with 100% NPK was recommended. Combined application of organic amendments and nitrogenous fertilizers gave Increased yields of BPT 1235 rice. At Jagtial, it was observed that when N dose was reduced to half of the RDF and applied in conjunction with poultry manure, the resulting rice grain yield (5073 kg ha -1 ) was on par with full dose of N applied treatments indicating an increase in applied N use efficiency besides confirming the desirability of conjunctive use of inorganic chemical fertilizers with organic manures. Complimentary use of green manures and urea, each supplying 50% of N significantly improved N recovery efficiency besides saving 50% of fertilizer N applied to low land rice. Maximum grain yield of 4.7 t ha -1 and a maximum N recovery of 66.1 percent were observed with the application of green manure along with urea to supply N at 60 kg ha -1 through each of them followed by the application of neem coated urea to supply N at recommended dose ( Table-19 ). Table-19: Effect of N sources on use efficiency of applied N by rice crop Treatments Grain yield Total N uptake Nitrogen recovery (t ha -1 ) (kg ha -1 ) efficiency (%) No- Control Urea, 3 splits FYM (40 N) + Urea (80 N) Nimin coated urea GM (60 N ) + Urea (60 N) LSD (0.05) CV (%) At Maruteru, under transplanted conditions, the rice seedlings treated with Azospirillum inoculation and Azospirillum broadcast (3 kg ha 1 ) in the main field before transplanting enhanced 59

60 the grain yield by 23.8 and 30.8 percent, respectively. Highest grain yield (5800 kg ha -1 ) was obtained when 40 kg N ha -1 was applied along with Azospirillum broadcast in the main field (ANGRAU, 2002). b) Maize Application of 4.5 t ha -1 and 100% RD FN to maize ( ) resulted in maximum grain and straw yields on an Alfisol of Hyderabad. However, the yields obtained were on par with those recorded with t PM ha -1 or t PM ha -1 ; the latter being recommended as it is cost effective. Application of 20 t ha % RDFN and 30 t sludge ha % RDFN to maize grown on Afisols and Vertisols, respectively were found to give maximum dry matter yield under pot culture conditions. However, the former was on par with 20 t ha % RDFN and, hence, it was recommended in order to reduce chemical load on soil. Seed inoculation with VAM and application of P at 30 kg P 2 O 5 ha -1 was equally beneficial as that of 60 kg P 2 O 5 ha -1 level to maize grown on Vertisol of Guntur district. At Chintapalle, in rainfed maize grown for green ears, maximum cob yield of 10,469 kg ha -1 was realized when full dose of N and P were applied in inorganic form and 50% K as niger ash and 50% K as MOP. c) Sorghum Dry matter production by sorghum grown on an Iso hyperthermic Typic Haplustalf of CRIDA, Hyderabad was higher with 100% N in the initial stages of crop growth. Later on with age, urea + gliricidia produced equal greater dry matter yield and grain yield. Application of sorghum straw caused reduction in dry matter production and grain yield. The N uptake also showed a similar trend. Agronomic efficiency and apparent N recovery were more with gliricidia than with sorghum straw treatments. In another case, application of P and Zn was found inferior to that where mycorrhizal inoculation coupled with P and Zn application was done. Rabi sorghum grown after French bean gave highest grain yield than after finger millet. d) Sugarcane The yield, uptake and % juice sucrose values increased significantly with the application of 100% RDFN + 75% RDP + phosphobacterin in both plant and ratoon crops. However, for economic application, the treatment 75% RDFN + 75% RDP + Azotobacter + Phosphobacterin was recommended for higher sugar yield. In another study, the results showed that irrespective of organic source (FYM or VC), applications of 75% and 100% fertilizer N significantly improved cane yields over other levels of fertilizer N application. Application of VC significantly gave higher cane yields of both plant and ratoon crops than with FYM at corresponding level of fertilizer N. Highest sugar yield was obtained with 75% RDFN + VC. Application of vermi compost + fertilizer N through urea to plant crop showed substantial residual effect on ratoon crop increasing its yield and nutrient uptake. For plant crop, the net returns were high with 25% VC + 75% fertilizer N while the ratoon crop got benefit through 75% VC + 25% N application. The results also indicated the distinct possibility of employing vermi compost technology for recycling of sugarcane trash, which is generated in significant quantities in sugarcane fields. Integration of chemical fertilizers with organic manures like 25 t ha -1 or pressmud 12 t ha -1 (4 t ha -1 on oven dry basis) or enriched pressmud 5 t ha -1 enhanced sugarcane yield at Anakapalle. Much differences were not observed between 75 and 100% RD of NPK treatments when these fertilizers were applied along with organic manures. Among the organic manures, enriched pressmud cake recorded lower cane yield 60

61 (72.7 t ha -1 ) than FYM (74.7 t ha -1 ) and pressmud cake( 73.1 t ha -1 ). At Anakapalle, significant improvement in yields of sugarcane to an extent of 39.9 percent over control (72.9 t ha -1 ) was observed due to integrated use of 75% RDF of N and P + composts (trash compost or vermi 2 t ha -1 ) + bio fertilizers 5 kg ha kg ha -1 ) resulting in the cane yield of 102 t ha -1, which was on par with application of 100% RDF of N and P (112 kg N kg P 2 O 5 ha -1 ) fertilizers (cane yield 98.9 t ha -1 ). e) Cotton At Nandyal, application of 100% RDF in conjunction with 5 t ha -1 gave significantly higher kapas yield in cotton (698 kg ha -1 ) as compared to control (502 kg ha -1 ). There was no significant difference in kapas yield due to seed treatment with bio-fertilizers (563 kg ha -1 ). f) Greengram Application of N at 20 kg ha -1 and inoculation with Rhizobium increased the yields of greengram (Pusa Baisakhi) grown on Alfisol. g) Blackgram Inoculation of blackgram with Rhizobium and application of phosphate increased protein content and yield of blackgram. Conjunctive use of P and biogas digest was found superior to P and FYM combination with respect to yields of blackgram (LBG-20). h) Bengalgram In medium P containing sandy clay soil, combined application of 50 kg P 2 O 5 ha -1 and inoculating with PSB and VAM was found economical for Bengalgram though 100 kg P 2 O 5 ha -1 + PSB + VAM gave the highest yield. i) Soybean Combined application of 5 t FYM ha -1 and 1 t PM ha % RDFN resulted in the highest dry matter production at flowering, grain and haulm yields of soybean besides high protein content of seed at maturity when grown on Alfisol of Hyderabad. j) Groundnut Nitrogen application at 20 kg ha -1 combined with Rhizobium inoculation increased yield, protein and oil contents of J-11 groundnut. The pod yield of intercropped groundnut (459 kg ha -1 ) was also significantly increased due to 100 NPK applied in conjunction with 5 t ha -1. Results of a permanent manurial trial conducted for 22 years on shallow Alfisols at Anantapur indicated that applications of 100 % N ( Groundnut N ha -1 ) and 100 % N ( Groundnut 20 kg N ha -1 ) +50 % NPK ( kg ha -1 ) were equally efficient while 50 % N 10 kg N ha -1 ) was the next best treatment for attaining sustainable groundnut yield ( Maruthi Sankar et al., 2010). 61

62 k) Castor At Palem, 75% RDF + 25% N through neem cake gave the highest yield of 1077 kg ha -1 in castor followed by 25% RDF + 25% N through FYM + 25% N through neem cake + GM (1062 ka ha -1 ). Yield and oil content in castor were increased by application of tank silt (100 t ha -1 ) with FYM (5 t ha -1 ) in combination with 40:40:0 NPK over all other treatments. Maximum uptake of nutrients was also observed. l) Sesamum Combined application of N at 25 kg ha 1 as urea and organic manure as groundnut shells at 5 t ha -1 resulted in higher yields of this crop when grown on a black soil. m) Sunflower Application of poultry 1 t ha -1 and 75% RDFN to sunflower grown on sandy clay loam soil and application of 50% N through VC and 50% RDFN on sandy loam soil were found not only increasing seed yields significantly but also increased nutrient uptake, oil and protein contents over other combinations. It was also found possible that in a medium P sandy clay loam soil, similar P utilization of that of 100% RDP can be obtained by reducing the dose by 20 to 30% and inoculated with PSB besides applying FYM. Combined application of 15 t ha % RD gave higher yields and good net returns in sunflower. This treatment also showed favorable effects on soil enzyme (dehydrogenase and urease ) activity, nutrient status of soils, yield, concentration and uptake of nutrients by sunflower. Application of mixture of vermi compost + fertilizers at 25 kg N ha -1 each gave highest sunflower yields both in kharif and rabi seasons. n) Safflower Azospirillum inoculation to safflower can be recommended in combination with 20kg N ha -1 as basal application as it gave seed yields and oil content on par with basal application of 40 kg N ha -1 thereby indicating a saving of 20 kg N ha -1 due to conjunctive use of nitrogen and bio fertilizers. o) Turmeric Application of 250 kg ha t ha -1 gave maximum yields of fresh rhizome yield ( t ha -1 ) closely followed by application of 250 kg ha t ha -1 (33.72 t ha -1 ) as compared to control ( no N /no manure treatment) with the yield of t ha -1. p) Onion Bulb yields of onion ( Nasik red) grown on an Alfisol showed increase even up to a level of 25 t FYM ha -1 and 200 kg K 2 O ha -1 apart from application of recommended doses of N and P. However, application of recommended dose of N+P with 12.5 t FYM ha -1 and 200 kg K 2 O ha -1 was on par with the above treatment. 62

63 q) Sweet Potato The tuber yield of sweet potato obtained with Azospirillum + 20 kg N ha -1 was on par with 40 kg N ha -1 indicating that Azospirillum can compensate up to 20 kg N ha -1. Azospirillum was found ineffective at higher levels of N application. r) Vegetable crops Vermi compost was proved to be a better organic source of N either individually or combinedly with inorganic fertilizers at 25 N + 75 VC, 50 N + 50 VC and 75 N + 25 VC. The root yields of radish were maximum at 50 N + 50 VC followed by 75 N + 25 VC which were significantly differing from each other. Application of castor cake at 6t ha -1 and N at 100 kg ha -1 gave significantly highest fresh weight and TSS of carrot crop. However, the combination of 4 t castor cake ha -1 and 100 kg N ha -1 was on par with the above treatment. Root yield of carrot was highest with K 120 kg ha -1 and FYM 15 t ha -1 besides increasing total K uptake by the crop. However, it was on par with the yields obtained with 80 kg K 2 O ha t FYM ha -1 and, hence, the latter was recommended for obtaining economic yield. Applications of 10kg N ha t VC ha -1 to bhendi, 50% RDFN + 50% N through VC or 50% RDFN + 6 t castor cake ha -1 for carrot 50% RDFN + 50% N through VC to radish, 100% NPK + 15 t VC ha - 1 to ridge gourd were found to give maximum yields besides improving the quality parameters in these crops. Productivity of tomato crop was found higher under INM with vermi compost besides GA 10 ppm at flowering. It was found that the cultivation of tomato with organic manures and plant growth regulators is more economical as compared to fertilizer application alone. It was also found out that 75% N + 25% N through VC + GA 10 ppm was superior to other treatments. Hence, in this treatment, GA 3 spray at flowering was recommended for optimum yields of tomato. s) Acid lime Application of FYM 25 kg + 2 kg /t Iron pyrites (IP) 200g plant -1 was found suitable for obtaining optimum yields and improving the soil fertility besides achieving maximum recovery from iron chlorosis in young acid lime orchards grown on calcareous red soils of Nellore district. The increase in nutrient uptake by individual manures and fertilizers followed the order: FYM > Pressmud > IP > VAM. t) Medicinal coleus Application of 50 %N as organic manure ( 2.5 t FYM ha -1 )+ Castor 0.25 t ha -1 + Azospirillum + PSB inoculation to medicinal coleus grown on a loamy soil was best. 63

64 Cropping systems a) Rice sunflower The dry matter yield at flowering, grain and straw yields at maturity were highest with the application of 25 % N as Poultry Manure (PM) + 75% RDFN ; the yields being 95.1, 55.0 and 73.3 q ha -1, respectively. This treatment was followed by 10 t ha % RDFN. The sunflower crop grown during rabi showed responses to residual quantity of inorganic N ; the responses being 5.5, 4.5 and 3.3 kg seed kg -1 of applied N in no green manuring, cowpea and pillipesera green manured plots, respectively. The total N removed by rice - sunflower cropping system was highest in treatment with 2 t ha % RDFN in no green manure (212.9 kg ha -1 ), cowpea green manured (236.7 kg ha -1 ) and pillipesara green manured (232.9 kg ha -1 ) plots. Highest net income from rice-sunflower cropping system was recorded in this treatment applied to rice followed by application of 40 kg N ha -1 to sunflower crop in rabi season. Under no green manuring conditions, there was depletion of available N, P 2 O 5 and K 2 O contents from soil. In case of treatment with green manure, depletion of N and build up of available P 2 O 5 and K 2 O were observed in control plots. A saving of 25 kg N ha -1 to rice and 40 kg N ha -1 to sunflower was noticed when treated with green manure crops. Highest net income from rice-sunflower cropping system was recorded in treatments with 2 tonnes PM ha % RDFN applied to rice and 40 kg N ha -1 applied to sunflower crops. These treatments together with inclusion of legume like cowpea or pillipesara in between rice and sunflower resulted in higher net income besides resulting in saving of 25 kg N ha -1 to rice and 40 kg N ha -1 to sunflower crops. b) Tomato - onion The dry matter, yields of fruits/bulbs, haulm yields of crops and nutrients uptake increased; the highest values being observed with vermi compost (VC). The values were, however, highest at 50% N as VC + 50% RDFN. The gross monetary returns were highest with 75% RDFN + 25% N as VC followed by 50% RDFN + 50% N as VC. Based on results, the latter was found useful for obtaining optimum yields of crops. Bulk density (BD) decreased with increase in application of organic matter along with fertilizers over RDF and control. Bulk density was lowest in vermi compost (VC) treated plots followed by plots treated with poultry manure( PM), Neem cake(nc) and FYM. Application of VC + fertilizer improved the Infiltration rate and hydraulic conductivity of soil. The activities of enzymes such as dehydrogenase, urease and phosphatase correlated significantly and positively with organic carbon of soil. c) Mesta based systems The total N removed by mesta - horsegram sequence was highest in the treatment 1 t PM ha % RDFN and same was the case with mesta-rice system; the values being and kg ha -1, respectively. The cost : benefit ratio was highest in case of treatment with Azospirillum as there was no much additional expenditure involved for purchasing this bio fertilizer. The options were suggested to farmers based on their economic conditions for obtaining economic yields. (i) Mesta horsegram: Options were given to mesta farmers of Srikakulam district based on their economic status when mesta-horsegram sequence was taken up. 64

65 Poor farmer Azorpirillum inoculation kg N ha -1 for mesta and 10kg N ha -1 to horsegram. Medium farmer: Application of 1 t PM ha kg N ha -1 to mesta and no fertilizer application or 10 kg N ha -1 to horse gram. Large farmer: 25 kg N ha -1 for mesta and 20 kg N ha -1 to horse gram. In case of mesta, 1t PM + 19 kg N ha -1 or 5t FYM + 19 kg N ha -1 are suggested as options. (ii) Mesta - rice: Poor farmer : Azorpirillum inoculation to mesta and application of 7.5 t ha -1. Medium farmer: 1 t PM ha kg N ha -1 to mesta and 40 kg N ha -1 to rice. If FYM is to be used, 10 t FYM ha -1 to mesta and 80 kg ha -1 to rice. Large farmer: Application of 25 kg N ha -1 or 1 t PM ha kg N ha -1 or 5 t PM ha kg N ha -1 to mesta and 80 kg N ha -1 to rice recommended. d) Rice - rice In alluvial soils of Godavari delta, application of FYM at 10 t ha t ha % RDFK resulted in highest dry matter yield at flowering and grain and straw yields at maturity with values of 71.6, 52.3 and 56.3 q ha -1,which were higher by 30.2, 30.9 and 14.1 per cent over control, respectively. The rice crop grown during rabi showed response to the residual quantity of inorganic K ; the responses being and 6.5 kg grain per kg applied K 2 O at no K,50 and 75 per cent RDK, respectively. Due to direct, residual and cumulative effects of added K, there was a net saving of 25 per cent RDK each in kharif and rabi seasons due to addition of organic manures (FYM or PM) with fertilizer K, while a net saving of 75 and 25 per cent can be achieved by addition of combination of organic manures with the fertilizer K. Under integrated P management in rice-blackgram and rice-rice systems, three methods of application of phosphate solubilizing bacterial (PSB) g powder were evaluated on P fixing clayey soil (Vertisol) in two rice-based cropping systems. In the previous year, seed treatment with PSB was superior to root dipping or field application recording 7.7 t ha -1 of rice equivalent yield (REY). However, REY was higher in rice-rice system (7.9 t ha -1 ) as compared to rice-blackgram (5.2 t ha - 1 ). The influence of blackgram in enhancing P use efficiency was apparent on kharif rice yields particularly in untreated control or field applied PSB plots (DRR, ). e) Rice maize Among different combinations of organic manures, bio fertilizers in integration with inorganic fertilizers, application of 75% RDFN + 25% N as VC resulted in the highest dry matter yield ( q ha - 1 ) at flowering, grain and straw yields of and q ha -1, respectively at maturity of rice. The maize crop grown during rabi responded favorably to the residual effect of treatments applied to rice as well as fertilizer N levels applied to it. The treatment of 50 % RDFN + 50 % N as VC applied to rice showed maximum residual effect on maize. Application of 100 % RDFN (120 kg N ha -1 ) resulted in highest dry matter production ( q ha -1 ), grain ( q ha -1 ) and stover (63.72 q ha -1 ) yields as well as uptake of nutrients. The total N removal by rice - maize cropping system was highest in treatment with 75 % RDFN + 25 % N as VC applied to rice at all levels of N application to maize. The net income was also highest in the treatment % RDFN applied to maize, however, it was on par with income at 50 % RDFN level. This indicates that the fertilizer needs of maize can be reduced by 50 65

66 % RDFN level by substituting 25 % fertilizer N through PM/VC/FYM +BGA to rice in this rice-maize system. At Rajendranagar, pre-kharif sown green manuring with greengram, sunhemp and dhaincha resulted in considerable increase in kharif rice and rabi maize yields. The grain yields recorded by kharif rice (5970 kg ha -1 ) and rabi maize (6000 kg ha -1 ) and at 75% RDF were found at a par with the yields recorded at 100% RDF by rice (6000 kg ha -1 ) and maize (6150 kg ha -1 ). The results suggest that practice of green manuring would help in saving 25% of fertilizers. out of 100% RDF in rice-maize cropping system. f) Sunflower sunflower The mixed feed vermi compost application resulted in superior stand and vigour of sunflower. The crop showed response up to 50 kg N ha -1 in both pot culture and field conditions. Application of vermi compost + urea (fertilizer) in 1:1 ratio to supply 50 kg N ha -1 resulted in 1878 kg ha -1 and 2160 kg ha -1 in kharif and rabi seasons, respectively. g) Sorghum-sunflower In the 5 th year of cropping with sorghum, clear crop growth differences were seen for various INM treatments. Use of FYM to supply 50% N requirement was superior to just Azospirillum seed treatment. Incorporation of crop residue of sunflower resulted in highest biomass yields while it decreased the grain yield of sorghum when both the crops were grown with their 100% RDF. The incorporation of residues of crops had significantly increased the grain yields of sorghum even with 50% fertilization as compared to non-utilization of residues. Sunflower crop did not exhibit significant growth and yield differences to INM treatments. However, the stem yield differed significantly. Highest seed yield of sunflower was recorded in treatment where sunflower was grown with RDF and preceding crop of sorghum was grown with 50% RDF + sunflower residue incorporation. Oil yield also followed a similar trend. h) Rice-pulse In a rice-blackgram sequence taken up on a sandy clay loam soil utilizing BGA inoculation (@ 10 kg ha -1 ), the highest grain yield was obtained at 80 kg N ha -1 level in combination with BGA. However, the response was more pronounced at lower level of 40 kg N ha -1 + BGA. BGA was found to substitute 40 kg fertilizer N ha -1. The yield of succeeding blackgram was markedly improved with increase in level of N along with BGA applied to kharif rice and was maximum at 80 kg N ha -1 applied in combination with BGA. i) Maize groundnut Among the different combinations tried, application of 75% RDFN+25% N through VC + 100% P 2 O 5 ha -1 resulted in the highest dry matter yield. (60.26 q ha -1 ) at flowering and grain ( q ha -1 ) and stover ( q ha -1 ) yields of maize at harvest. Similar results were observed even under greenhouse conditions. The increase in all these parameters was attributed to initial N status of the soil of experimental field. 66

67 Among the treatments tried on maize, the residual effects on groundnut with respect to dry matter yield ( q ha -1 ) at flowering, kernel ( 16.36q ha -1 ) and haulm ( 34.0 q ha -1 ) yields at harvest were highest with the application of 50 % RDFN + 50 % N through VC and 100 % P 2 O 5 ha -1. Among the cumulative effects, application of 50 % RDFN + 50 % N through VC % P 2 O 5 to maize and 75 % RDFN to groundnut showed the highest dry matter yield ( q ha -1 ) at flowering, kernel ( q ha -1 ) and haulm ( q ha -1 ) yields at harvest. The cumulative effects were found to be more than their respective residual effects on groundnut crop. The fatty acid profiles were studied for both the crops of maize and groundnut under the influence of different treatments. In corn, the linoleic acid (18 : 2) was found to be the major fatty acid followed by oleic (18 : 1) palmetic ( 16 : 0),stearic (18:0) and linolenic (18:3) acids in increasing order of their concentrations. Increased levels of inorganic N decreased the contents of palmitic, stearic, oleic and linolenic acids but increased the contents of linoleic acid. In case of groundnut, the oleic acid was found to be the major fatty acid followed by linoleic, palmitic, arachidic and stearic acids in decreasing order of their concentration. Application of increasing levels of N led to decrease in contents of plamitic and oleic acids while the contents of linoleic acid was increased. However, a definite trend was not observed with stearic and arachidic acids. At the end of sequence, there was depletion of saloid- P and Ca-P contents in control plots while a built up was noticed in Al-P and Fe-P under cumulative effect with an exception to Fe-P, which showed depletion under residual effects. The maximum activities of enzymes viz., urease ( 6.32 ug of NH 4 + -N released g -1 soil h -1 ), acid phosphatase (43.27 ug of p nitro phenol released g -1 soil h -1 ), alkaline phosphatase ( ug of p-nitro phenol released g -1 soil h -1 ) and dehydrogenase ( 1.14 mg TPF produced g -1 soil d -1 ) were observed in the treatment 50% RDFN + 50 % N through VC + 100% P 2 O 5 to maize and 75% RDFN to groundnut crop showing cumulative effect at the end of sequence. j) Maize-soybean The maize - soybean system was taken up on a sandy loam soil. Integrated use of organic manures and inorganic fertilizers increased the dry matter yield, grain and straw/ haulm yields of crops. The beneficial effects and net profit were more with 75% RDFN + 25% N as VC followed by 50% RDFN + 50% N as VC. However, the latter was recommended due to cost prohibitiveness of vermi compost. The yield increase in both crops and monetary returns were highest under VC followed by PM, BGS and FYM in that order. Conjunctive use of organic manures and inorganic fertilizers significantly influenced the activities of dehydrogenase, urease and phosphatase enzymes in soil. The enzymatic activities were lower in rabi soybean crop than the kharif maize crop. k) Sorghum-greengram In a long-term trial of sorghum-greengram cropping, the highest sorghum grain yield (2370 kg ha -1 ) was obtained with combined application of 4 tonnes of FYM + 20 kg N or 2 tonnes gliricidia + 20 kg N per hectare. Under reduced tillage also, the treatments performed well. For greengram, performance of almost all the treatments was comparable, among which 1 t gliricidia + 10 kg N (993 kg ha -1 ) per hectare and 2 tonnes of FYM + 10 kg N per hectare (843 kg ha -1 ) out yielded under conventional and reduced tillage conditions. The change in organic carbon content with sorghum- 67

68 greengram rotation after 5 th year of the experiment (2002) ranged from 0.51 to 0.80 percent and 0.55 to 0.85 percent under conventional and reduced tillage, respectively; maximum being noticed with 4 tonnes of FYM + 2 tonnes gliricidia ha -1. l) Turmeric- maize intercropping This system was taken up on a sandy loam soil at RARS, Jagtial. Application of inorganic fertilizers in conjunction with FYM and PM besides tank silt significantly improved soil properties. The dry matter production and nutrient uptake were highest with full RDF ( kg N, P 2 O 5 and K 2 O ha -1, respectively) + 5 t ha -1 followed by 2/3 RDF + 5 t ha -1. Based on the improvement in soil properties and for obtaining economic yields, the latter was recommended. Integrated nutrient management in crops and cropping systems is now being given greater attention in the state and it helped to make several useful observations for improving soil fertility, crop nutrition and productivity of crops (Table-20): Table-20: Recent studies on INM Title of the study Place of study Best performing treatment Effect of INM with gliricidia College Farm, 50% NPK through as green manure in ricerice Rajendranagar fertilizer + 50 % crop sequence (2008- NPK through 09) gliricidia in kharif and 100 % NPK through fertilizer in rabi Effect of INM with gliricidia as green manure in rice mustard crop sequence ( ) Effect of organic farming in rice-rice crop sequence on yield of rice ( ) Effect of organic farming in turmeric-sesamum crop sequence ( ) Regional Sugarcane& Rice Research Station (RS & RRS), Rudrur Regional Agricultural Research Station (RARS), Maruteru 75% NPK through fertilizers + 25% NPK through gliricidia in kharif and 75 % NPK through fertilizers in rabi 50 % NPK + % 50% NPK through FYM Kharif yield (kg ha -1 ) 3974 (rice ) 5210 (rice) 5357 (rice) RS & RRS, Rudrur -do (turmeric) Rabi yield (kg ha -1 ) 4132 (rice) 785 (mustard) 5547 (rice) 516 (sesamum) Influence of INM on soil and plant N Maximum increase in dry matter yield of rice was seen with Azolla (13.21 g pot -1 ) followed by gliricidia ( g pot -1 ), which were superior to N applied at 100% as urea alone (11.87 g pot -1 ). The grain and straw yields of rice followed the order: Azolla > gliricidia > PM > FYM > BGS. The N uptake 68

69 was also highest with Azolla and gliricidia. The N fractions responsible for variation in available N content were total hydrolysable N, hydrolysable NH 4 -N and acid insoluble N, whereas variation in total N in soil was meager during crop growth. The regression analysis showed that hydrolysable NH 4 - N, hexosamine and serine + threonine N fractions were responsible for influencing dry matter yield and uptake of N by rice. The exchangeable NH 4 - N and total hydrolysable N and serine + threonine were depleted among N inorganic and organic fractions, respectively INM in dry land agriculture The results of several experiments showed that a benefit of substitution of percent inorganic fertilization is possible by applying organic manures. This benefit is still more in cropping systems as residual effects of applied manures and fertilizers is tapped by subsequent crops grown in the systems and good effects of growing legumes can also be harnessed as biologically fixed nitrogen is also made available through crop residues. However, the situation is different with dry land agriculture, where water is a limiting factor for successful crop production. It even alters the nutrient use efficiencies. Under conditions of growing single crop annually depending upon the quantum of rain received, the scope of extending INM to dryland agriculture may not be remunerative though the benefits of components of INM are seen on individual crops. Hence, the results obtained under irrigation have to be appropriately modified to make it relevant to dryland agriculture. The dry land farmers use not only FYM but also take up sheep penning for improving the productivity of their fields. Growing cowpea, and horsegram as green manures and utilizing sesbania, gliricidia, sunhemp, and leucaena loppings as green leaf manures were found useful in dryland areas. Since mixed cropping or intercropping are commonly practiced in dryland fields, it will be beneficial if these species are utilized appropriately as green manures. The best way will be through harvesting the first flush and then incorporating it into the soil. The green leaf manuring will help to achieve similar benefits where time and space are problem for growing the green manure crops (Sreenivasa Raju and Vittal, 2004) Nutrient gains in INM Nitrogen gains through application of FYM to crops depends on the soils and crops growing environments. In case of low land rice, savings of 30 to 40 kg N ha -1 were reported when grown on sandy clay loams and loamy sand soils receiving applications of 10 and 12 t ha -1, respectively. Poultry manure, which is having a lower C : N ratio when compared with FYM can substitute up to 75 kg N ha - 1. Maize crop grown on loamy sand soil under upland conditions showed a gain of fertilizer N equivalent up to 60 kg N ha -1 when FYM was applied at 10 t ha -1. Results of long term fertilizer experiments conducted at several locations all over India with a treatment using FYM conclusively showed that application of 100% NPK (recommended) together with 10 t FYM ha -1 is as good or even better than application of 150% NPK to crops. Nitrogen gains through bio fertilizers are, however, highly variable. Results of research also indicated the possible reduction in doses of fertilizer K application, secondary and micronutrients when organic manures were applied in combination with inorganic fertilizers. 69

70 Use of components of INM by farmers of Andhra Pradesh Surveys have been carried out on fertilizer use in several parts of the state to understand the pattern of usage of fertilizers, manures and bio fertilizers by farmers for crop production purposes (Subba Rao et al.,2001). The types of manures and fertilizers being used by farmers in different parts of the state are presented in Tables 21 and 22, respectively. Among the manures, FYM followed by sheep penning was used by farmers of the state. Use of castor cake and neem cake was observed in Kadapa, Anantapur and Nellore districts by a few farmers. Green leaf manuring is followed in Chittoor, Kadapa, Anantapur, Khammam and Ranga Reddy districts while use of green manure crops for improving soil fertility was adopted by farmers in many districts. Use of poultry manure is seen in Kadapa, Anantapur, Nizamabad and Nellore districts only by very few farmers. Tank silt is used in Karimnagar district. The survey indicated that some farmers in Kurnool, Kadapa, Mahabubnagar and Ranga Reddy districts were not using organic manures at all for crop production purposes (Table21). Predominant use of urea and DAP by farmers is also reflected in the state wide survey carried out by ANGRAU recently (Sreenivasa Raju and Padma Raju, 2000). Ammonium sulphate and CAN are used by a few farmers of Nizamabad, Warangal and Nellore districts. Complex fertilizers such as , , , and are in use by very few farmers in different districts (Table 22). The complex fertilizer is used in Kadapa, Anantapur and Khammam districts only. Farmers are seen investing large amounts on purchase of fertilizers. However, indications are there that certain farmers of Vizianagaram and Visakhapatnam districts are not using any type of inorganic fertilizers for crop production purposes. The survey further indicated that all these types of fertilizers were adequately available in markets in the state. Table 21: Trends in use of manures by farmers of Andhra Pradesh District No. of farmers No. of farmers using Sur- veyed F YM SP CP Cast or Ca ke Nee m Cak e PM G M GL M Pig Not Compost Manure Using Kurnool Chittoor Kadapa Anantapur Khammam I

71 Khammam II Medak Nizamabad I Nizamabad II Adilabad Karimnagar (TS) Warangal Vizianagaram Visakhapat-nam Srikakulam Nellore East Godavari Guntur (PP) Mahaboob nagar Ranga Reddy SP = Sheep penning CP= Cattle penning TS = Tank silt PP = Pig penning PM = Poultry manure GM = Green manure GLM = Green leaf manure 71

72 Table-22: Trends in use of fertilizers by farmers of Andhra Pradesh S. N o. District No. of farm - U SSP M O P A S CA N D A P No. of farmers using ers surv eyed ZnS0 4 Not usi ng Kurnool Chittoor Kadapa Anantapur Khammam -1 Khammam -II Medak Nizamabad I Nizamabad II Adilabad Karimnaga r Warangal Vizianagar

73 1 am 1 2 Visakhapat nam Srikakulam Nellore East Godavari Guntur Mahaboob nagar Ranga Reddy SO P Unfortunately use of bio fertilizers is not making any headway in utilization for crop production purpose in Andhra Pradesh (Table-23). Several farmers expressed that they were not aware of the beneficial effects of the bio fertilizers. Those who are aware were also not using them due to lack of information on places where the materials can be procured. However, in some districts (Anantapur, Adilabad, Chittoor and Nellore), very few farmers are using the Rhizobium for groundnut and Azotobacter and Azospirillum to cereal and commercial crops. 73

74 Table-23: Awareness among farmers of Andhrapradesh about certain components of INM in crops Place/district No. of Farmers surveyed Bio fertilizers Soil testing INM Balanced fertilization Yes No Yes No Yes No Yes No Kurnool Chittoor Kadapa Anantapur Khammam I Medak Nizamabad I Adilabad Karimnagar Warangal Khammam-II (Madhira) Nizamabad Rastakuntabai (Vizianagaram) Visakhapatnam Naira(Srikakulam Nellore Pandirimamidi (East Godavari) Total

75 Reddy et al. (1997) carried out a study to examine the fertilizer use derivations in case of three important crops viz., rice, sorghum and groundnut in Andhra Pradesh. In case of rice, the per hectare fertilizer use ranged from 80 kg in Penumantra to 366 kg in Mantralayam. In most places, excess use of nitrogen and phosphorus was observed. In contrast, application of potash was meager. In case of sorghum, fertilizer use ranged from a mere 3 kg ha -1 in Mantralayam to as high as 100 kg ha -1 in Penugonda. No fertilizer was applied in tribal areas of Hukumpet and Rampachodavaram. The nitrogen deficiency in sorghum was attributed to reluctance or inability of farmers to top dress this nutrient. Regarding the fertilizer use in groundnut crop, greater degree of derivations from recommended doses were observed. It was emphasized that the fertilizer use is to be increased wherever found underused while excess use is to be discouraged. Shaik Haffis et al. (1997) also observed greater degree of deviations in fertilizer use from recommended doses in production of different crops across different agro-climatic zones of Andhra Pradesh. While N was applied excessively, P and K were underused at most of the places surveyed whereas fertilizer use was considerably high in case of irrigated crops. Madhava Swamy and Subba Rao (1995) observed that the farmers of scarce rainfall zone were applying more of nitrogen through chemical fertilizers to paddy, cotton, chillies and less in sorghum, bajra, setaria and tobacco. Similarly, use of phosphorus was more in paddy, cotton, chillies and onion and was less in bajra, setaria, irrigated sunflower and bengalgram crops. They further observed that farmers were using more of complex fertilizers than straight fertilizers, which was causing imbalance in fertilizer use. Lack of awareness about the recommended doses of fertilizers and lack of knowledge about conversion of different fertilizers into their nutrient forms were identified as reasons for the imbalanced use of fertilizers. More than half of the farmers surveyed indicated that they were using increased rates of fertilizers in spite of higher costs of these materials (Table-24 ). In another survey carried out by Sreelatha (1998) on 222 mesta farmers,the observations showed that 2, 5, 87, 56 and 22 farmers were using one, two, three, four and five types of fertilizers, respectively in crop production. While urea is the straight fertilizer predominantly used by all the farmers, among the complex fertilizers, DAP was preferred. Here too, indications were there that the farmers were using fertilizers either in much excess or less quantities than recommended doses. Financial condition of the farmers is stated to be the main reason for low usage of chemical fertilizers as mesta farmers, in general, are poor in economic condition. Regarding usage of organic manures by these farmers, all of them were found using FYM in their fields. This was followed by sheep manure, paddy straw, green manure and neem cake in that order. Farmers were depending upon combination of sources too. While 41 farmers (18.7%) were using FYM alone, 93 (41.7%) farmers were using two sources out of which one was FYM. Three types of manures were found used by 33.2% (74) farmers. There were 9 and 5 farmers depending upon 4 and 5 types of organic sources of nutrients, respectively. The survey, thus, showed that the farmers are aware of use of manures for crop production. However, it was found that they were not applying the materials as per recommended doses. The quantities of FYM being used was ranging from 2 to 10 t ha -1 against the recommended doses of 10 to 15 t ha -1 for several of the crops grown in the district. In majority of the cases, 75

76 Table-24: Fertilizers applied by farmers under different situations during in Scarce Rainfall Zone Crop/situation No. of farmers surveyed Yield (q ha -1 ) Nutrients through fertilizers (kgha -1 ) Recommended dose of nutrients (kg ha -1 ) N P K N P K 1. Paddy a. Irri. Black soil b. Irri. Red soil Overall Sorghum a) Rainfed black b) Rainfed red c) Irri. Black soil d) Irri. Red soil Overall Bajra Rainfed Red soils 4. Setaria a. Rainfed black b. Rainfed red Overall Cotton a. Rainfed-Black- Mungari do

77 Hybrid b. Rainfed-Red- Mungari Rainfed-Red- Hybrid c. Irri. Black- Hybrid d. Irri. Red Hybrids Overall Groundnut a. Rainfed black soil b. Rainfed red soil c. Irri. black soil d. Irri. red soil Overall Sunflower a. Rainfed black soil b. Rainfed red soil c. Irri. black soil d. Irri. red soil Overall Castor Rainfed red soil Bengal gram Rainfed black & red

78 10. Coriander Rainfed black soil Rainfed red soil Overall Tobacco Rainfed black soil Chillies Irrigated black & red Onion Irrigated black & red Tomato irrigated red 15. Oranges (Santra) black & farmers are depending upon the FYM generated in their cattle sheds while a few of them purchase either partly or wholly required quantity from others for use in their fields. In another survey carried out by Madhava Swamy and Subba Rao (1995) in the Scarce Rainfall Zone it was observed that only one third of the farmers were applying organic manures in lower quantities than recommended to all the crops Management of fertilizers in problem soils Combined application of gypsum, zinc sulphate and ferrous sulphate at two levels of NPK (i.e. N 80 P 50 K 30 and N 120 P 60 K 40 ) resulted in higher growth and yield attributing characters in case of rice when compared with individual applications of either gypsum or zinc sulphate. Application of NPK at 78

79 recommended level (N 120 P 60 K 40 ) along with zinc sulphate was found to give higher cost: benefit ratio in Vertisol. The following were the varieties / lines of different crops which showed tolerance to soil salinity (Table-25): Table-25: Salinity tolerant varieties of different crops Crop Rice Blackgram Cotton Tolerant varieties/lines Deepthi, NLR-30981,NLR-33641,Surekha, Cul-1317,Prakash, Chaitanya, Swarna, Rasi, Jaya and Vijetha. LBG-22,LBG-402,LBG-623, LBG-611,LBG-738,and LBG-726 G.cot Dh-7, NHB-12,NHH-302 and Hy-4 Chillies X-235,CA-960,and G-4 Groundnut Gingelly Castor Safflower Sugarcane Coriander ICGV-87189,ICGV-86309,Girnar-1, ICGS-1,ICGS-5,ICGS-65 and ICGS-44 Gowri SHB-18,48-1 and Gauch-1 HUS-305,T-65,and Bhima 83v288 CS Soil test crop response correlation studies Paddy Studies on soil test crop response correlations were carried out on paddy grown on black clay loam soils and fertilizer adjustment equations were developed. The studies indicated that KMnO 4 - N, modified Olsen s P and NH 4 OAc-K were suitable to predict the availability of N. The equations developed were as follows: a) Surekha Targeted yield FN = 4.95 T 0.50 SN where T= Targeted yield F P 2 O 5 = 2.24 T SP Maximum yield FN = SN F P 2 O 5 = SP 79

80 Maximum profit FN = SN 21.8 R FP 2 O 5 = SP 4.84 R ( Where R= Ratio of cost of unit of fertilizer per price of unit of grain yield ) b) Pothana Targeted yield FN = 6.66 T SN F P 2 O 5 = 3.89 T SP Maximum yield FN = SN (% OC-N) FP 2 O 5 = SP ( Olsen s P) Maximum profit FN = SN R F P 2 O 5 = SP R c) Surekha kharif Targeted yield FN = 5.75 T 0.75 SN F P 2 O 5 F K 2 O = 2.75 T 3.94 SP = 1.99 T 0.12 SK Maximum yield FN = SN F P 2 O 5 = SP F K 2 O = SK Maximum profit FN = SN R F P 2 O 5 F K 2 O = SP R = SK R For this paddy variety, these equations were developed for rabi season also. Similarly, using basic data, targeted yield equations were developed for maize, jowar, sunflower and onion crops grown on different soils. 80

81 Maize: Kharif ( Jagtial - Northern Telangana Zone) FN = 4.19 T 0.40 SN F P 2 O 5 = 1.50 T 1.55 SP F K 2 O = 1.49 T 0.16 SK Rabi (Rajendranagar Southern Telangana Zone) FN = 4.00 T 0.49 SN F P 2 O 5 = 2.15 T 2.58 SP Jowar : Rainfed ( Palem Southern Telangana Zone) Sunflower F K 2 O = 2.58 T 0.30 SK FN = 7.29 T 0.82 SN F P 2 O 5 = 4.30 T 1.53 SP F K 2 O = 5.10 T 0.52 SK For sunflower crop grown on Vertisol, the nutrient requirement of N, P 2 O 5 and K 2 O were 9.96, 1.21 and kg per quintal of seed yield, respectively. The contributions (%) from soil and fertilizer were 55.8 and 121 for N, 25.2 and 13.6 for P and 22.9 and for K, respectively. The targeted yield equations were FN = 8.23 T 0.46 SN F P 2 O 5 F K 2 O = 8.91 T SP = 3.80 T 0.10 SK Onion The nutrient requirement for production of 1 quintal onion bulbs were 0.260, and kg for N, P 2 O 5 and K 2 O, respectively. Targeted yield: Rabi crop FN = 0.59 T 0.48 SN (Sothern Telangana Zone) F P 2 O 5 = 0.80 T 2.10 SP F K 2 O = 0.41 T 0.14 SK Kharif crop F N = 0.83 T 0.43 SN ( Southern Telangana Zone) F P 2 O 5 = 0.96 T 1.76 SP 81

82 F K 2 O = 1.15 T 0.41 SK Tomato (rabi) Southern Telangana Zone ( Alfisol Palem ) F N = T 2.28 SN F P 2 O 5 = 1.78 T 1.14 SP F K 2 O = 6.82 T 1.02 SK Coriander (kharif) - Scarce Rainfall Zone (Vertisol- Kurnool) F N = T SN F P 2 O 5 = 9.31 T SP F K 2 O = T SK Colocassia (rabi) - Southern Zone ( Alluvial soils - Nellore) Chillies F N = T 0.53 SN F P 2 O 5 = 6.70 T 1.84 SP F K 2 O = T 0.64 SK For the kharif crop grown in the Krishna Godavari Zone, the following equations were developed at Lam Farm,Guntur: F N = T 0.84 SN F P 2 O 5 = 3.43 T 1.68 SP F K 2 O = T 0.60 SK Cotton (rainfed) The following equations were developed for the cotton (rainfed) grown on Vertisols of Kurnool in Scarce Rainfall Zone: F N = T 0.70 SN F P 2 O 5 = 8.96 T 2.15 SP F K 2 O = T SK Sugarcane The sugarcane crop was grown in Nellore and Rudrur belonging to Nellore and Nizamabad districts, respectively as main/ratoon crop for which the following equations were developed: 82

83 i) Nellore- Main crop ( Southern zone ) F N = 3.47 T 1.60 SN F P 2 O 5 = 1.30 T SP F K 2 O = 2.10 T SK ii) Nellore- ratoon crop ( Southern zone ) F N = 4.66 T 2.05 SN F P 2 O T 7.34 SP F K 2 O = 1.53 T 0.60 SK iii) Rudrur (Kharif crop) - Northern Telangana Zone F N = 5.40 T 1.25 SN F P 2 O 5 = 1.80 T 4.73 SP F K 2 O = 1.70 T 0.33 SK ( F N = Fertilizer N, F P 2 O 5 = Fertilizer P 2 O 5 and FK 2 O = Fertilizer K 2 O S N = Soil N, S P 2 O 5 = Soil P 2 O 5 and S K 2 O = Soil K 2 O - all in kg ha -1 T = Yield target q ha -1 ) In these studies, ready reckoners were developed for application of N, P 2 O 5 and K 2 O based on soil test values to achieve different targeted yields prescribed for these crops. 10. Status and management of salt affected soils In a study carried out in the South Coastal districts of Krishna, Guntur, Prakasam and Nellore, the delineation of saline soils was done utilizing the satellite data. Major soils existing in this area are red, black, alluvial and coastal sands. Based on salinity, they were grouped into 12 categories. Out of the total area affected by salinity and sodicity ( 2,25,787 ha), Prakasam had the highest extent of 83,209 ha followed by Nellore ( 65,405 ha), Krishna ( 42,235ha) and Guntur ( 34,938 ha). The salinesodic soils were dominant (1,19,956 ha) whereas saline soils and sodic soils occurred to the extent of 80,991 ha and 24,890 ha,respectively. Several agronomic measures were suggested including growing salt tolerant crops and their varieties. Apart from this, the chemical amelioration cost was estimated at Rs. 148 crores, which includes the cost of gypsum required for treating the sodic soils. Among the hinterland districts, satellite data indicated that this problem existed in 7500,450 and 795 ha of land in Nalgonda, Adilabad and Khammam districts,respectively. 83

84 The extent of salt affected soils, specifically the sodicity are not very high and hence, no serious work on their reclamation was carried out in the state. However, the technologies developed by research works carried out where they are predominantly occurring are also useful for reclamation of the local salt affected soils. A few pertinent technologies are as follows: Since accumulation of soluble salts is the major problem in these soils, efforts must be made to remove them from soil and conducted to a distant place from the affected field(s).good quality irrigation water be used for impounding in the field in small plots made by earthen bunds forming upto suitable height so that the standing water will have to percolate through the profile only. Normally, in areas where the problem is existing, the quality of water may not be good to serve this purpose. Rain water must be utilized and it serves better than the irrigation water, as the latter has some salts dissolved in it unlike the former. The extent of such removal is usually calculated by using an equation for knowing the leaching requirement which takes in to account the salt contents of both the soil and water used for leaching. It was estimated that nearly 3.5 and 8.1 lakh hectares of area are affected by the problems of water logging and salinity, respectively in the state. The Indo-Dutch Net work Project on Drainage and Water Management for Control of Salinity and Water Logging in Canal Commands was in operation during with the finances from the Government of Netherlands through ICAR, New Delhi. The Project successfully implemented the drainage and water management technologies in the fields of farmers in Konanki and Uppugunduru in Prakasam district. For areas with sandy loam to clay loam soils as in Nagarjuna Sagar Project right canal command area and Krishna Western Delta to control salinity, sodicity and water logging problems, laying out a pipe drainage systems with the specifications given in table - 26 are recommended ( Satyanarayana et al.,2003) : Table-26: Specifications for drainage pipes laying out in salt affected fields Area Rainfall (mm) Drainage spacing (m) Drain depth (m) NSP Right canal Command (sandy loam to clay loamy soils) Krishna Western Delta ( Sandy clay loam soils) to 1.35 In areas with high salinity problems, open drains lower the salinity levels very fast. Though these are cheaper, small holders may resist their laying out due to loss of cultivable land in construction of drains. In such cases, a drain spacing of 75 m and drain depth of 1.0 to 1.2 m can be suggested. After introduction of sub surface drainage, the following soil and water management practices will help to reduce the salinity and sodicity problem further and crop growth in such fields will also be better: 84

85 Apply 25 % of more N than the recommended. Apply organic manures 5 t ha -1 ) along with zinc kg ZnSO4 ha -1 ) in sodic soils. Green manure crops like dhaincha can be grown and ploughed in situ for the reclamation of sodic soils. Apply gypsum ( at 50 % Gypsum Requirement) on the basis of initial soil test value for the reclamation of sodic soils where the ph is > 9.0 and in black soils. Growing salt resistant varieties suitable to the area concerned. These measures in general are suitable for all salt affected saline and sodic soils in the state. Thus, application of organic manures has a great role to play in ameliorating saline and sodic soils. Different bulky organic manures, green manures, crop residues, molasses and sugar factory pressmud, certain weeds like Argemone mexicana etc. will help to reduce the problem in these soils. It is always advisable to keep the area under vegetation by growing cover crops or grasses and keeping them off from grazing will definitely help in reclaiming these soils. A specific agro forestry system was designed by Central Soil Salinity Research Institute (CSSRI), Karnal known as Pancholi system selecting suitable tree species like Acacia arabica, Azadirachta indica etc. The chemical amendments such as gypsum, sulphur, ferrous sulphate lime sulphur, aluminum sulphate etc. serve the purpose of reclamation of saline-sodic and non saline-sodic soils more effectively. Among these, gypsum is the cheapest source for reclamation and exhibits good residual effect even on Ca and S nutrition of crops grown. Based on the results of Gypsum requirement test, the quantities to be applied are decided. Application of chemical amendment, as suggested for high efficiency, must be followed by application of copious amount of irrigation water to leach the salts and replaced sodium. Adoption of suitable agronomic practices will help avoiding the recurrence of the salts problem within a short period of time after reclamation. 11. Quality of waters In the ground water survey carried out in 11 districts, the salinity problem was observed in Guntur(18.3 %), Prakasam (18.6%), West Godavari (16.8 %), Krishna ( 15.8 %),East Godavari ( 10.7 %) and Nellore (9.4 % ) districts while it was low in Khammam (1.5 %), Mahabubnagar (3.0 %),Anantapur (1.7 %),Nalgonda( 5.64 %) and Kurnool (6.9 %)districts. Classification of ground water in different districts of Andhra Pradesh was also done. Out of 684, 166, 837, 140, 825, 501, 544, 621, 927, 815 and 1131 samples collected from Anantapur, Prakasam, Guntur, East Godavari, West Godavari, Krishna, Khammam, Kurnool, Nellore, Nalgonda and Mahabubnagar districts, and examined,306, 62, 537, 105, 685, 331, 437, 414, 340, 425 and 637 samples, respectively were found of good quality. The remaining samples were showing different degrees of salinity and sodic nature. The underground waters used in different sugar factory areas in North Coastal Zone viz., Thummapala (Anakapalle), Chodavaram, Etikoppaka, Bhimisinghi, Amudalavalasa, Hanuman Junction, Payakaraopeta, Chelluru, Pithapuram and Samalkota, varied degrees of salinity were noticed while sodicity problem was not prevalent. Such observations were also made in and around Empee Sugars and Chemicals Ltd. In Nellore district. The water from underground wells used for irrigating citrus gardens in this district 85

86 were also found to have salinity while the water from Telugu Ganga Canal was of very low salinity level. The irrigation waters used in betel vine gardens in Guntur district were saline to severely saline and are of poor quality Management practices suggested for irrigation with saline waters In order to overcome the adverse effects of using such bad quality waters in coastal saline areas, certain management practices were suggested. These include: Incorporation of 5 t ha -1 or 15 t ha % of the recommended dose of N Adopting closer spacing with 50 percent more plant population than normal Application of 50 percent more N and P than the recommended dose Conjunctive use of two canal irrigations followed by one saline water irrigation to crops Avoiding use of saline irrigation water at germination, flowering and grain filling stages of the crops Application of 500 kg ha -1 at pegging stage of groundnut Combined application of 2.5 t ha -1 of green leafy manure t ha -1 of FYM to paddy crop Improved Doruvu technology has been developed for horizontal skimming of fresh water floating over the saline ground water with tile drains laid out for this purpose in coastal sands to irrigate vegetables, flowers and raising rice, tobacco and casuarina nurseries. 12. SOIL POLLUTION Urban solid wastes The urban solid wastes (USW) generated in Hyderabad were highly heterogeneous and contained less plastic, paper, metal and rubber compared to the wastes generated in other developed countries. The contents of gravel, soil and dust were more in these wastes. The COD of wastes was ranging from 89.0 to mg g -1 while the organic carbon content varied from 3.4 to 6.3 percent. Land application of 33 t ha -1 benefited maize,which also showed increase in uptake of Pb, Ni and Co. The Pb absorbed tended to be in roots and didn t get translocated to edible parts of the shoot. The USW of Gandhamguda land fill (GLF) site was highly alkaline and causing increase in concentration of several metals at the site. The urban solid wastes, market wastes and farm wastes were found to be alkaline in reaction and had high organic carbon contents of 28.6, 34.8 and 36.0 per cent, respectively. The COD values were 345, 488 and 505 mg g -1 and C:N ratios were 42.7, 32.5 and 44.4 with USWs, market wastes and farm wastes, respectively. Fly ash soil application at 10 t ha -1 and application of N,P and K at recommended doses resulted in good performance of groundnut crop grown on a sandy loam soil. Application of 10 or 20 t ha -1 fly ash alone did not show significant effects on rice and sugarcane, respectively. However, application of fly 10 t ha -1 along with farmer s practice of application of fertilizers or recommended doses of fertilizers increased the yields of JGL-1798 rice. 86

87 12.2. Industrial effluents The analysis of waters from Noor Ahmed Tank, Rajendranagar indicated that the EC, BOD, COD, TDS, contents of micronutrients and heavy metals increased substantially and irrigation with these waters led to failure of germination of seed in different crops, which was attributed to high EC and ESP. The industrial effluents of Uppal Industrial Development Area (UIDA) were found to be strongly alkaline in reaction. The EC, organic carbon, available macro, micronutrients and heavy metal contents were high near the site showing a decrease with increase in distance. The well waters nearby had more concentrations of several of these elements. Application of spent wash (distillery effluent) after diluting 5 times with irrigation water resulted in significantly increased dry matter of bajra and blackgram crops as it favourably influenced the soil environment with respect to ph, EC, OC, CEC, N,,K, S, Zn, Fe, Mn and Cu as compared to irrigation with normal water. However, maximum yields were obtained when treated with 10 and 20 times diluted effluent in bajra and blackgram, respectively Sewage waters The sewage waters generated at sewage treatment facility at Amberpet were within the safe limits in case of ph, EC, dissolved oxygen, BOD, TS and B while TDS, TSS, Cl - and SO = 4, Na + Ca ++ and Mg ++ were beyond permissible limits. Heavy metals except Mn, Cd and Cr were below the contents suggested as critical limits. The pollution was high during summer season. Plant uptake studies showed higher amounts of heavy metals in fodder grass than vegetables and crop plants. Para grass was better than panicum and maize in uptake of trace elements and heavy metals. The elements were found accumulating more in roots than in foliage and stems except in radish. The analysis of raw sewage water at Maize Research Station, Amberpet indicated presence of soluble salts, COD, Cd and Cr beyond tolerable limits and, hence, need to be treated before using for irrigation purposes. Continuous use of this raw water resulted in increase in CEC due to addition of silt and clay besides increasing the DTPA extractable contents of micro nutrients and heavy metals. However, the uptake of these metals didn t cause any adverse effects on maize as they were within the toxic limits Sewage sludge In tomato cabbage cropping sequence, the highest fruit yield (43.12 t ha -1 ), plant dry matter (3156 kg ha -1 ) and fruit dry matter (3105 kg ha -1 ) of tomato were recorded in treatment with sewage sludge applied at 40 t ha -1 along with 100 % RDF. The highest concentrations and uptake of N,P, K, Fe, Cu and Zn in tomato plant and fruits also were observed in this treatment. This was closely followed by the treatment with application of 40 t ha -1 of sewage sludge and 75% RDF. Regarding the concentration and uptake of heavy metals ( Pb, Ni, Co, Cr and Cd),the former treatment showed the highest. Even the urban compost treatments showed the higher concentrations and uptake of heavy metals than FYM indicating that both the sewage sludge and urban compost are sources of pollutants. The cabbage crop grown during rabi showed significant change in fresh head yield, plant dry matter and head dry matter due to the residual effect of manures applied to the preceding crop of tomato with change in levels from 20 to 40 t ha -1. Accumulation of major nutrients was more in the edible parts of tomato and cabbage than in plant. Unlike the major nutrients, the micro nutrients ( Fe, Mn, Cu and Zn) showed accumulation in plant than in the edible parts of both the crops. All the heavy metal concentrations in the plant as well as in the edible parts of both the crops were below the safe 87

88 limits. Based on economics and pollution aspects, to obtain higher income and to maintain better soil conditions, application of sewage 40 t ha -1 along with 75% RDF was recommended for the tomato - cabbage sequence Status of heavy metals in peri urban Hyderabad A survey was carried out in highly heavy metal contamination prone areas viz., Musi river bed and Kattedan Industrial area to study the long term effect of sewage and industrial effluents on soils, crops and ground water. Among the different parameters studied, the ph, EC, BOD,SO 4 =, SAR, Zn, Pb,Ni and Co were found within the safe limits for irrigation while Ni and Zn were found within the permissible limits for drinking purposes. Whereas, in water sample collected from Kattedan Industrial area, except Mn, all other parameters were found within the safe limits for irrigation while Ni, Cd, Zn, Ca, Mg, TSS, Na, and SO 4 = were found within permissible limits of drinking. However, both these waters were found not suitable for drinking due to other parameters. The soils of Musi river bed area were found contaminated more than those of Kattedan Industrial area as the contents of Zn, Cu, Fe, Mn, Cr, Co, Ni, Cd and Pb exceeded the permissible limits in the former. In the Kattedan Industrial area, except Fe, Mn and Co, all other metals were within the permissible limits. The analysis of plants indicated that Pb was present in contents exceeding the permissible limits in edible parts in plants grown in Musi river bed area while the rest are present in permissible limits. While the accumulations of nutrients and heavy metals were least in edible parts, the highest accumulation was found in roots. It was inferred that though the consumption of produce from crops is safe at present, it may lead to health hazards due to consumption for prolonged periods by human beings and animals Absorption of heavy metals by crops and animals The analysis of vegetable crops grown in the surrounding areas of UIDA and GLF indicated higher concentrations of heavy metals, which are harmful to humans. Crops grown near the USW disposal (Land fill) sites at Amberpet, Golkonda and Auto Nagar showed increased absorption of Zn, Cu, Pb and Ni actively indicating possible pollution threat. In a study on affect of polluting effluent streams on ground water quality, soil properties and on the consumption of plants under Patancheru, Kattedan, Nacharam and Jeedimetla environs, adverse effects were seen due to use of polluted ground water near the stream, which decreased with distance. The index leaves of rice, sorghum, maize, wheat, groundnut and sugarcane growing in these polluted environs showed relatively higher contents of N,P,K, Zn, Fe, Mn, Cu and heavy metals as compared to those grown in pollution free environments. The adverse effects of Cd application on growth of fodder jowar, greengram and lucerne were observed to be more severe in red soils as compared to black soils. Similarly, the adverse effects of Cd application were more severe in legumes than in the cereals. Among legumes, greengram was least affected. Increasing Cd concentration decreased the nutrient uptake by crops and also led to the accumulation of it in kidney, liver and muscle in poultry depressing the growth rate of fowls. Cadmium concentrations in kidney and liver of chicken after 6 weeks of growth with Cd included feed led to the accumulation of 0.4 and 1.96 times more, respectively than in muscle. 88

89 12.7. Amelioration of polluted soils In order to overcome the adverse effects of heavy metals on vegetable crops, zeolites, quicklime, vermi compost and excess P were tried as decontaminants. Application of these materials reduced the DTPA extractable Pb, Cd, Ni, Cr and Co contents by 45 th day of contact. Zeolites and quicklime were found to leave maximum depressive effects on these toxic metals extractability using DTPA. On the other hand, application of vermi compost maintained relatively higher levels of these metals. Zinc and manganese contents weren t depressed by the decontaminants tried. Copper behaved similar to that of Pb, Cd and Ni. Zeolites at 0.5 percent on weight basis and quick lime at 500 mg kg -1 were found equally effective in depressing the concentration of toxic metals in amaranthus. Since the latter is cheaper, it is recommended for ameliorating polluted soils. The excessive application of P can also act as an alternative. While heavy metal contents in leafy vegetables viz., Amaranthus, hibiscus and palak increased with the addition of P from 0 to 20 kg ha -1 in case of Pb, Cr and Cd, the contents of Co and Ni decreased. Application of 200% P depressed total toxic metal load by about 19.6 percent over control. The order of different treatments in bringing about the depressive effects on toxic metal loads in leafy vegetables followed the order: 40 kg P 2 O 5 ha -1 (200% RDP) +2 t VC ha -1 > 40 kg P 2 O 5 ha t VC ha -1 > 40 kg P 2 O 5 ha -1 > 60 kg P 2 O 5 ha - 1 (300% RDP) > 60 kg P 2 O 5 ha t VC ha -1 > 20 kg P 2 O 5 ha t VC ha -1 > 20 kg P 2 O 5 ha t VC ha -1. With heavy metals, the depressive order was : Cr ( 15.95% ) > Pb (13.88%) > Cd (13.75%) > Co (13.74%) > Ni (11.60%). In case of crops, hibiscus > palak > amaranthus can be grown in that order. Hence, growing hibiscus with application of 40 kg P 2 O 5 ha t VC ha -1 along with 20 kg N ha kg K 2 O ha - 1 was recommended for polluted soils of Musi river banks in Hyderabad Effect of aquaculture on soil and water quality In Prakasam district, the qualities of pond water/ground water from wells/ filter points/ hand pumps/ ponds at different lateral distances from aquaculture ponds and soils were studied. The soluble salt content of ground water adjoining the fresh water fish culture ponds was above the permissible levels at 10 m distance from the pond at Rebala and up to 330 m at Purini whereas this parameter in case of brackish water prawn culture ponds was above the permissible levels up to 295 m distance from the pond at Karedu-1,upto 338 m distance from pond at Karedu-2 and up to 390 m distance from the pond at Kolladinni. The mean EC of soils adjoining brackish water aquaculture ponds ranged from 0.02 to 22.95, 0.04 to and 0.42 to d Sm -1 at Karedu-1, Karedu-2 and Kolladinni, respectively. The mean EC values of soils adjoining fresh water aquaculture ponds ranged from 0.71 to 5.10, 0.52 to and 1.19 to d Sm -1 at Rebala, Kovuru and Purini, respectively. The adverse soil salinity effect was observed up to 200, 200, 100, 50, 100 and 200 m distance at Karedu-1, Karedu-2, Kolladinni, Rebala, Kovuru and Purini, respectively. The accumulation of heavy metals and presence of higher amounts of nutrients (N,P,K and micro nutrients) were noticed in the immediate vicinity of brackish water ponds than the areas adjoining fresh water ponds. In a survey of Guntur, Prakasam, Nellore,Krishna and west Godavari districts where prawn culture area lies, the findings were that the paddy crop in the adjoining fields of aquaculture ponds was affected severely up to 20 m away and thereafter the severity decreased with distance. When trenches were made around the ponds, the problems of salinity weren t there. In Prakasam district, when such trenches weren t dug up, subabul plants showed drying up due to high salinity in the adjoining fields. 89

90 13. Management of soil physical environment Effect of tillage on soils and crops In dry land agriculture, timeliness and precision in field operations are vital for successful crop production. To ensure proper tillage with different implements, experiments were conducted on Rhodustalfs of Anantapur growing groundnut after summer rains. The results showed that the implements used for primary tillage significantly influence soil moisture in the profile after receipt of rains. Chekkala guntaka and country plough usage significantly contributed to increase infiltration rate and soil moisture status, though BD was not affected significantly. Primary tillage every year had better cumulative effect. Soil moisture conditions due to usage of these equipments correlated well with chlorophyll as well as active Fe contents. The P-uptake by groundnut and dry matter yield were related to active root distribution of the crop. Tillage is important particularly in rice based cropping systems as the crop grown after rice is normally affected due to spoilage of structure etc. due to rice culture. Sunflower is being grown after rice on Alfisols in Southern Telangana region of Andhra Pradesh. The results of a field experiment indicated that the seed bed preparation involving the disc plough and rotavator (both tractor drawn) resulted in better tilth and created desirable soil physical environment i.e. deeper tillage, smaller size clods with low MWD (29mm), lowest BD (1.32 Mg m -3 ), highest hydraulic conductivity (5.49 cm h -1 ) highest infiltrations rate (4.33 cm ha -1 ) and lowest penetration resistance (27.0 kg cm -2 ). This resulted in increased seedling emergence, higher dry matter and seed yield (989 kg ha -1 ) of sunflower in puddle rice fallows. Since the highest seed yield of 1080 kg ha -1 was obtained with 100% RDF, deep fine tilth with disc plough + rotavator once (both tractor drawn) coupled with 100% RDF is suggested. The favorable effects of tillage on sandy clay loam soil put to sunflower after rice were also seen. The results of the study showed that tillage with rotavator (either of tractor drawn or power tiller operated) resulted in smaller size clods ; indicated by low MWD (20mm) and low BD as compared to secondary tillage with cultivator. In the treatment with tillage through disc plough once and rotavator twice (both tractor drawn), root growth of sunflower was better. The LAI, head size, dry matter production,100 seed weight, seed and oil yield of sunflower were maximum due to deep and fine tilth brought about by this treatments. The moisture regime created by giving irrigation (6 cm of water at each irrigation) at IW/CPE of 1.0 and tillage as indicated above results in high WUE too and, hence, these are recommended for growing sunflower after puddled rice on these soils. In another field experiment, the effect of tillage treatments on soil physical properties such as depth of tillage, clod size distribution, MWD, bulk density, total pore space, hydraulic conductivity, infiltration rate and penetration resistance of soil were assessed in rabi seasons of and in a sandy clay loam soil of Hyderabad growing sunflower as test crop in the rice based cropping systems. The tillage treatments viz., T 1 : country plough twice + cultivator twice ( both bullock drawn ), T 2 : country plough twice + power tiller operated rotavator twice and T 3 : Disc plough once + rotavator once ( both tractor drawn), in general, improved soil physical environment for upland crops in rice based cropping systems. Deep tillage (18 cm) was achieved when preliminary tillage was carried out with tractor drawn disc plough while the depth of tillage was confined to 11 cm with cattle 90

91 drawn implements. Secondary tillage with rotavator either tractor drawn or power tiller drawn produced finer seedbed indicating low mean weight diameter ranging from mm of dry clods resulting in higher seedling emergence of per cent. The step down regression equation indicated the dependence of seedling emergence on MWD of dry clod in seed bed ( R 2 = 1.00). Individual effects of deep tillage with fine seed bed, irrigation given at IW/CPE =1.0 and 100% recommended dose of fertilizer resulted in higher net returns as compared to other treatments. Hence, based on the results, the package comprising tractor drawn disc plough once + rotavator once, irrigation at IW/CPE of 1.0 and 100 per cent recommended dose was suggested to maximize the yield of sunflower grown after puddled rice in sandy clay loam soils in rice based cropping systems Land management practices The penetration resistance was found lower in broad bed and furrow (BBF) system by 9.3 and 15.5 kg cm -2 than that were observed in ridges and flat beds, respectively. The total porosity of soil in BBF was higher by 4.0 and 8.3 percent than the ridges and flat beds, respectively. Maximum pod yields of ground nut ICG ( FDRS) 10 and ICGS-11 varieties were observed in BBF and it was more by 11.9 at 20.5 percent than with ridges and flat bed systems, respectively, which was attributed to the increase in soil moisture retention, decrease in BD and penetration resistance. In a study on soybean based system taken up at ICRISAT, Hyderabad on a Vertic Inceptisol, it was observed that soil properties viz., available N, soil respiration, microbial biomass C and N were significantly influenced by the land form and soil depth treatments under intercropped systems with chickpea and pigeon pea. Available N was more in flat land than in BBF. Between the pigeon pea and chickpea crops, the former in BBF was found to fix more N than in flat bed system. Sole crop of soybean fixed more N than intercropped system. Soybean grown on medium deep soil fixed more N than in shallow soil. The land form and soil depth significantly influenced uptake of N and P by the crops. The amount of NO 3 -N lost in runoff water was larger in flat bed (13 kg N ha -1 ) than in BBF (10 kg N ha -1 ) land form. In developing surface management techniques to reduce soil structural problems and enhance profile moisture storage, thereby decreasing deep percolation losses and modifying solute movement, tillage, application of residues and conditions of surface and surface roughness are important considerations. In another study at ICRISAT, using bromide as a tracer, it was observed that the revegetation treatment recorded the highest moisture storage in the soil profile besides showing the most rapid bromide flux. However, bromide flux was higher in fallow treatment than in cropped treatments thus, indicating that there was improvement in soil aggregation and aggregate stability in the latter. Scoop treatment improved surface roughness which also enhanced aggregation and aggregate stability. Performance of pearl millet was better in revegetation plots followed by PVA, crop residue, scoop and control plots in that order. In a long-term experiment with pearl millet (Pennisetum glaucum) taken up at ICRISAT, Hyderabad to evaluate practices to improve infiltration and reduce erosion by stimulating biological activity and protecting soil in the rainy season, the results showed that millet straw yield was reduced by tillage to 20 cm and grain yield was significantly reduced by tillage to both 10 and 20 cm. Mulches had no effect on millet straw yield but FYM significantly increased millet grain yield. The proportion of 91

92 rainfall running off plots ranged from 15.8 to 39.1 percent. Rice straw mulch significantly reduced runoff in comparison with FYM and no mulch. Soil was lost mainly as suspended load, indicating that raindrop detachment was the main erosion process. Tillage significantly increased suspended load concentration in the first major runoff event but not in an event later in the season. It appears that improved farming systems are needed to enhance productivity and reduce degradation on hard setting Alfisols in the semi-arid tropics Effect of conservation tillage Formation of ridges and furrows along the contours with khus grass (vegetative barrier) was found to result in highest reduction in run off (90.2%) and soil loss (91.95%). Water use efficiency (kg/ha-mm ) was more in deep tillage with khus (6.96) followed by deep tillage (6.02) and ridges and furrows with khus (6.28) against sowing along slope (4.57). In a specific study on castor grown on a local Alfisol with 2.5% slope using khus barrier, it was observed that conservation tillage practices reduced the run off and soil loss, increased the soil moisture content, plant characteristics and seed yield of the crop. Maximum reduction in these parameters was noticed in ridges and furrows formed along the contour with khus barrier. Dead furrow with khus barrier was the next best in all aspects. Water use efficiencies were high with best treatments. Based on the results, sowing of castor on contours with ridges and furrows formed in combination with khus barrier at 1 m vertical gradient is recommended for shallow Alfisols and under rain fed conditions. For better and early establishment of vativer, pruning of roots to 10 cm size bits was useful than either 5 cm root pruning or no root pruning. The growth and nutrient uptake were maximum at this pruning level either with or without application of fertilizers. Planting 4 strips per hill with closer spacing of 7.5 cm resulted in higher percentage of establishment and greater growth than with 2 strips per hill. Hence, planting roots having 10 4 strips per hill at 7.5 cm spacing is recommended for its serving better as a vegetative barrier under rain fed conditions Effect of physical environment on certain plant parameters Under greenhouse condition, the 5 sorghum cultivars viz,. CSV 8R, SPV 504, SPV 913, M 35-1 and SPH 5041 grown on red sandy loam soil showed variation in rooting pattern. The variety CSV 8R followed by SPV 504 extracted a minimum quantity of water. A maximum drought tolerance index of 7.7 was observed with M 35-1 followed by SPV 504 ( 7.62). In another study, 8 sorghum cultivars (CSH 13 R,SPV 913,SPV 839, M 35-1, Lakadi, Swarna,CSV 8R and CSH 12 R ) were grown on red chalka soil. Among these, SPV 839 had a greater root length of 25 cm, which was 4 percent greater than the local variety M The variety SPV 839 showed the highest grain yield of 7135 kg ha -1 and was the best drought tolerant cultivar of sorghum as it extracted 30.8 cm of water only against 31.6 cm of water extracted by the local variety (M 35-1). In a greenhouse study, the germination and emergence of pearl millet, sorghum and groundnut grown on Alfisol were studied. The results showed that increasing BD had considerable effect at low soil moisture contents. A BD of g cm -3 and moisture content ranging from

93 percent were found favorable for germination and emergence of seedlings of all the crops. A B.D. of 1.65 g cm -3 was found critical for emergence of pearl millet and sorghum crops. Germination was found affected at a moisture content of 19 percent. In case of groundnut, a population density of 5.0 lakh plants ha -1 under favorable rainfall conditions increased the degree of aggregation by 4.41 percent, mean weight diameter by percent and hydraulic conductivity by percent over a population density of 3.33 lakh plants ha - 1.The improvement was attributed to increased root growth, which favored soil aggregation. Plant population had also influence on ET as computed by different formulae /equations. Seasonal crop ET increased significantly with increase in plant population density. Significant correlations were observed between crop ET and evaporation from USW Class A Pan. At the plant population density of 5 lakh ha -1, the highest pod and haulm yields of groundnut were recorded even for per unit quantity of water used resulting in maximum net returns and high cost : benefit ratio Relationships between soil separates and water retention Knowledge of soil water retention and its availability is important for better soil water management and crop yield. Water retention at 0.1,0.33 and 15 bar tensions varied from 1.71 to 40.11,1.54 to and 0.54 to per cent,respectively and these showed significant positive correlations with clay, silt, silt + clay, organic carbon, CEC and significant negative correlations with sand and bulk density. For soils of Srikakulam district, prediction equations relating to water retention at 0.1, 0.33 and 15 bar tensions and contents of sand, silt and clay have been developed as follows: W 0.1 = sand silt clay (R ) W 0.33 = sand silt clay ( R2 =0.81) W 15 = sand silt clay ( R2 = 0,82) Available water content varied from 1.00 to per cent and showed increase with depth in many soils Movement of water The unsaturated hydraulic conductivity of water in Alfisol field was studied. The results showed that in the initial stages, the volumetric moisture content ( θ ) varied from 24,58 to percent in the profile 24 hours after irrigation was stopped. Over a drainage period of 3 days, θ was found decreased in the soil profile. The reduction of θ was rapid in the first 8 days and then it was gradual during rest of the period, The ψ m in the profile also reduced similar to the pattern of reduction in θ. Over a drainage period, the K (θ ) varied from 1.00 to 3.73 x 10-4 cm day -1 with an associated decrease in ψ m from to percent in the profile Scheduling of irrigation to crops In order to schedule irrigation for okra and cluster beans grown at Rajendranagar, the ET estimates obtained with different equations were compared. The ET values of 4.5,4.7 and 5.0 mm 93

94 day -1 were observed with Hargreaves, Blaney-Cridddle and modified Penman formulae, respectively showing that the former two recorded 10 percent less values than the last one. Increase in moisture extraction as well as yields of crops were noticed when irrigation was done at 20 cm pan evaporation Method of irrigation and mulching Drip irrigation was found to show higher soil moisture content by 10.7 and 15.0 percent at 0-15 and cm depths, respectively as compared to surface irrigation. Mulching helped to conserve more moisture than unmulched condition indicating that black polythene mulch increased moisture contents by 11.6,12.9 and 32.0 percent and paddy husk by 11.3,7.0 and 7.8 percent in 0-15, and cm depths, respectively over unmulched plots. Irrigating bell pepper with drip resulted in significantly higher (22.5%) green fruit yield than with surface irrigation. Drip irrigation at 0.6 ET and use of black polythene mulch was found the best combination for irrigating this crop as there was increase in water storage and WUE (0.91 t /ha-cm). Realization of optimum yields of grain sorghum grown on dry land Alfisols mainly depends upon soil moisture which can be improved by stover mulching or residue application; the latter being useful even for improvement of physical properties of soils. The results of a study conducted at CRIDA, Hyderabad showed that stover mulching /residues application at the rate of 4 t ha -1 with 120 kg N ha -1 gave optimum yield of grain sorghum grown on Alfisol provided the rain fall distribution is proper during crop season. When dry spell occurred during critical growth stages of crop, one or two supplemental irrigations resulted in realization of optimum grain yield of sorghum in Alfisols Influence of applied nutrients on soil physical conditions Tillage with rotavator and tractor drawn implements on a loamy sand soil put to groundnut and application of 90 kg P 2 O 5 ha -1 to the crop showed significant increase in root growth and dry matter accumulation. Groundnut crop grown on red chalka soil showed response to application of zinc due to not only supply of this nutrient but also because of certain favorable effects on soil physical parameters, specifically due to improvement in degree of aggregation. 14. Soil moisture studies Very few studies were carried out on the soil moisture to indicate its support to crop growth, specifically in drought prone areas. In place of soil moisture, available water capacity is reported. The 94

95 latter is dependent on the amount and intensity and distribution of rainfall, infiltration, permeability, type of clay minerals, texture,depth and gravel contents in soil. The data were generated for all the 23 districts on the available water capacity (Table-27) by the NBSS & LUP, Nagpur (Reddy et al.,1996) and that information was utilized to work out the length of growing period (LGP) of crops. The ratings followed were : Very low - < 50 mm/m; Low 50 to 100 mm/m; Medium 100 to 150 mm/m; High 150 to 200 mm/m and Very high- >200 mm/m. It was observed that 22.33, 13.24, 35.32, 5.81 and per cent of total area in the state has very low, low, medium, high and very high available water status, respectively. The high and very high categories have potential to support the growth of long duration crops. The data on soil water balance as a relationship between rainfall and temperature indicating the length of growing periods of crops in the drought prone places are presented below ( Figure -2) : The management of soils for increasing the available water capacity include deep management, early sowing of crops, choice of drought tolerant crops and their varieties which can use moisture efficiently, maintaining optimum plant population, inter/mixed cropping as an insurance against crop failure, moderate use of fertilizers, timely weeding and pest control, ratooning of the drought affected crops on receipt of rain, sowing alternate crops in case of crop failure during midseason, impounding of rain water through farm ponds for supplemental irrigation to save the crop and also for recharging the ground water, alternate land use systems such as agro forestry agrihorticulture, silvi-pasture and alley cropping and in situ moisture conservation by application of mulches. Water availability period for crop production was found to range from 120 to 229 days in the State( Piara Singh and Virmani,1995). The duration of water availability was greater than 180 days at Kalingapatnam, Hanamkonda, Hyderabad deep Vertisols, Kakinada, Gannavaram, Machilipatnam,Ongole and Nellore, while it was less than 140 days at Nizamabad, Mahabubnagaar, Giddalur, Anantapur and Arogyavanram. At other locations, the availability period ranges from 140 to 180 days. Using the water balance model, it was observed that the probability of soil profile retained water up to 50 percent available water holding capacity (AWHC), was greater for the locations like Visakhapatnam and Hyderabad in North, and Mahabubnagar in South, indicating more assured soil water availability in Northern Andhra Pradesh. In the South, the probabilities of rainfall are low and also the soil moisture is available for a shorter duration, especially at Kurnool and Anantapur. The moisture adequacy, which is a reliable index for knowing the availability of water to the crop, value was equal to 0.5 or more for Visakhapatnam,Hyderabad and Mahabubnagar for 21 to 24 weeks. At Kurnool, the value was 0.75 for 8 weeks, 12 weeks at Ongole, 4 weeks at Anantapur and 12 weeks at Kadapa. These observations indicate that the water is sufficient in rainy season in Northern districts while in the South, the crops are subjected to drought more frequently. The models of yield through soil moisture at 30,60 and 90 DAS had coefficient of determination in the range of 0.13 for 50 %N (FYM@ 10 kg N ha -1 ) to 0.45 for 100 % NPK ( kg ha -1 ) + ZnSO kg ha -1.The effect of soil moisture on pod yield was negative on 30 and 60 DAS, while it was positive on 90 DAS ( Maruthi Sankar et al.,2010). The rate of change was positive at 90 DAS with values ranging from 1.42 for control to 6.30 for 100 % NPK ( kg ha -1 ). 95

96 Table-27: Available water capacity in soils of different districts S. No. District Available Water Capacity (mm/m) 1 Adilabad Anantapur Chittoor Kadapa East Godavari Guntur Hyderabad Karimnagar Khammam Krishna Kurnool Medak Mahaboobnagar Nalgonda Nellore Nizamabad Prakasam Ranga Reddy Srikakulam Visakhapatnam Vizianagaram Warangal West Godavari On a sandy clay loam soil at Rajendranagar, the effects of tillage induced soil physical properties and soil moisture regime on performance of sunflower in rice based cropping systems were studied by Gurumurthy (1990). The results showed that the deep fine tillage and wettest soil moisture regime,both individually and combinedly resulted in higher crop water use followed by tractor drawn mould board plough and cultivator, country plough twice + power tillage with rotavator, countryplough twice + bullock drawn cultivator and zero tillage in descending order. In general, bulk of the moisture required was extracted from the surface layer (0-15 cm). However, with increase in depth of tillage, extraction of water from deeper layers relatively increased. The water use efficiency was higher in deep tillage treatments than others. Munaswamy (1995) conducted an experiment with groundnut grown on rainfed Alfisol of Anantapur and reported that the implements used for primary tillage significantly influenced soil moisture status in the profile following receipt of rains (Table-28). Use of Chekkala guntaka and country plough significantly contributed to increase in the infiltration rate and soil moisture status. 96

97 Table 28: Soil moisture (mm- at 0-30 cm depth ) fluctuation throughout the season under different methods of primary tillage DAS T-1 T-2 T-3 T-4 T-5 T-6 T-7 T (T-1 = No primary tillage; T-2= Blade harrow;t-3=chekkala guntaka;t-4=tractor drawn tiller ;T-5 =Tractor drawn chisel; T-6 =Country plough alone;t-7 = Country plough + Groundnut shells@ 4t ha -1 ; T-8= Country plough + Pearl millet t ha -1 ) Table-29: Moisture stored in the profile with use of PVA Treatment Moisture stored in the profile (mm) Control kg ha kg ha kg ha kg ha kg ha S. Em(+/-) 2.7 C.D.(0.05)

98 Figure - 2: Soil water balance at different stations in Andhra Pradesh R= RECHARGE S=SURPLUS U= UTILIZATION D=DEFICIT 98

99 R= RECHARGE S=SURPLUS U= UTILIZATION D=DEFICIT 99

100 100

101 R= RECHARGE S=SURPLUS U= UTILIZATION D=DEFICIT 101

102 R= RECHARGE S=SURPLUS U= UTILIZATION D=DEFICIT 102

103 R= RECHARGE S=SURPLUS U= UTILIZATION D=DEFICIT 103

104 R= RECHARGE S=SURPLUS U= UTILIZATION D=DEFICIT 104