Effect of integrated nutrient management on soil properties under cottonchickpea cropping sequence in vertisols of Deccan plateau of India

Indian J. Agric. Res., 49 (3) 2015: 207-214 Print ISSN:0367-8245 / Online ISSN:0976-058X AGRICULTURAL RESEARCH COMMUNICATION CENTRE www.arccjournals.com/www.ijarjournal.com Effect of integrated nutrient management on soil properties under cottonchickpea cropping sequence in vertisols of Deccan plateau of India Nitin Gudadhe*, M.B. Dhonde and N.A. Hirwe Department of Agronomy, Mahatma Phule Krishi Vidyapeeth, Rahuri-413 722, India. Received: 25-06-2014 Accepted: 22-01-2015 DOI: 10.5958/0976-058X.2015.00032.3 ABSTRACT An experiment was conducted at Mahatma Phule Krishi Vidyapeeth (MPKV), Rahuri a representative place for the vertisols of Deccan plateau of India to study the effect of organic and inorganic fertilizers on crop yield and soil physical, chemical and biological properties in the cotton-chickpea cropping sequence. There were seven treatments applied to hybrid cotton and each plot of summer cotton was equally divided into four parts to chickpea. Application of Recommended Dose of Fertilizer (RDF) according to Soil Test Crop Response (STCR) equation recorded significantly higher seed cotton yield and cotton equivalent yield, however it was at par with 10 t Farm Yard Manure (FYM) ha -1 + RDF. Chickpea registered significantly higher seed yield in 10 t FYM ha -1 + RDF and it was at par with 100% RDN through vermicompost. 100% RDF registered significantly superior seed chickpea seed yield and cotton equivalent yield. The soil physical, chemical and biological properties determined at the end of two crop cycles were improved due to the application of manures in sole or in combination with chemical fertilizers. Key words: Chickpea, Cotton, Cropping sequence, INM, Soil properties, Vertisols. INTRODUCTION In India, vertisols cover an area of about 72.9 million ha, constituting roughly 22.2% of the total geographic area of the country. (Hati et al., 2006). In India, these soils are predominantly found in Deccan plateau of Maharashtra. These soils are dominated by a smectite group of clay minerals, leading to expansion and shrinkage on wetting and drying. From the viewpoint of crop production, low organic matter is one of the major constraints in addition to low plantavailable nutrients, particularly nitrogen (N), phosphorus (P), and zinc (Zn), thus affecting the productivity of these soils (Blaise et al., 2005). The predominant cropping pattern followed in medium to deep vertisols is cotton and cotton-based systems. There are reports that when cotton is grown continuously, soil fertility decline because of the wider nutrient removal use gap. Quality and productivity of black soils can be improved by adopting suitable practices such as inclusion of legume e.g. chickpea in rotation with cotton and other main crops, integrated use of organic and inorganic sources of nutrients, and balanced fertilization. Chickpea plays a significant role in improving soil fertility by fixing the atmospheric nitrogen. Chickpea meets 80% of its nitrogen (N) requirement from symbiotic nitrogen fixation and can fix up to 130 kg N ha -1 from atmosphere. It leaves substantial amount of residual nitrogen for subsequent crops and adds plenty of organic matter to maintain and improve soil health and fertility (Gaur et al., 2010). Supplementing the nutrient requirement of crops through organic manures e.g. vermicompost, farm yard manure etc., especially plays a key role in sustaining soil fertility and crop productivity, reducing use of fossil fuels and restoring overall soil quality. These sources are often cheaper and more efficient than inorganic compounds. Organic materials hold great promise as source of multiple nutrients because of their ability to improve soil characteristics. Intensive land use with continuous use of higher doses of inorganic fertilizers significantly influences soil health and crop growth. But this has raised concerns about the potential longterm adverse effects on soil health and environmental quality. However, the use of organic manure is limited by the huge quantities needed to meet crop nutritional needs, while the use of chemical fertilizers is limited by cost and scarcity. Complementary use of organic *Corresponding author address: Department of Agronomy, Navsari Agricultural University, Navsari-396 350, Gujarat. *Corresponding author s e-mail: nitbioworld@nau.in, nitbioworld@gmail.com.

208 INDIAN JOURNAL AGRICULTURAL RESEARCH and inorganic fertilizers may be beneficial for achieving a sustainable crop production. Cotton-chickpea cropping system is one of the economically remunerative system in rainfed vertisols of Rahuri, representing the Deccan plateau. Yield of this cropping sequence affected by poor soil quality because of the low organic-matter content, poor fertility, and poor physical and biological conditions. Based on the foregoing discussion, an experiment was initiated by following appropriate nutrient-management. MATERIALS AND METHODS Field experiment was conducted during 2006-07 and 2007-08 at Mahatma Phule Krishi Vidyapeeth (MPKV), Rahuri, Dist. Ahmednagar, Maharashtra, India to find the effect of different organic and inorganic sources either alone or in combination on yield and soil physical, chemical and biological properties in hybrid cotton-chickpea cropping sequence under in Mula river command area. Agroclimatically, the experimental site falls under semi-arid zone and climate of this ecosystem is characterized by hot and dry summer and winter ranges cool to mild. The annual rainfall ranges between 272-790 mm. The soil of the experimental field was medium black and fairly drained. The textural class was clayey. A dominant type of clay mineral was montmorillonite and grouped under order vertisol. The chemical composition indicated that the soil was low in available nitrogen (168 kg ha -1 ), medium in organic carbon (0.52%), low in available phosphorus (13.36 kg ha -1 ) and high in available potassium (367 kg ha -1 ). The soil was alkaline (ph 8.01) in reaction. The experiment was laid out in two designs, randomized block design for cotton cv. Phule-392 with seven (7) treatments with three replications (7 treatments x 3 replications = 21 plots) during summer season and after the harvest of cotton, each plot of cotton was divided into four equal sub plots for sowing chickpea cv. Digvijay, with four levels of fertilizers with three replications hence total number of plots for rabi season became (7 treatments X 4 levels x 3 replications) = 84 in split plot design during rabi season to test the residual effect of summer cotton treatments on rabi chickpea with three replications. Hence there were seven treatment allocated with three replications for summer cotton as a main plot treatment viz. 10 t farm yard manure (FYM)/ ha + recommended dose of fertilizer (RDF) as 100:50:50 kg NPK /ha, 75 % RDF + 25 % recommended dose of nitrogen (RDN) through vermicompost, 50 % RDF + 50% RDN through vermicompost, 25 % RDF + 75 % RDN through vermicompost, 100 % RDN through vermicompost, RDF according to soil test crop response (STCR) equation and control. During rabi season each plot of cotton was divided into four equal plots for four fertilizer levels as a sub plot treatments viz. control, 50 % RDF, 75% RDF and 100% RDF were applied @ 25:50:00 kg NPK/ha to chickpea during rabi season. Farm yard manure (FYM) contained 0.55% N, 0.31% P, and 0.59% K while vermicompost (VC) had 1.33% N, 1.20% P, and 1.29% K, respectively. The fertilizers were applied to the treatment no. 6 as per the targeted yield equations developed by Soil Test Crop Response (STCR) Project, MPKV, Rahuri for summer cotton. Before planting of summer cotton, the soil was analyzed for available NPK (kg ha -1 ) and analyzed values were put in following targeted yield equation of summer cotton. The targeted yield for summer cotton was 25 q ha -1 for both the seasons. Targeted yield equation (STCR) F N = (13.1 x T) (0.75 x SN) F P 2 O 5 = (6.83 x T) (2.83 x SP) F K 2 O = (8.75 x T) (0.18 x SK) Where, FN = Nitrogen (kg ha -1 ) to be applied from fertilizer FP 2 O 5 = Phosphorus (kg ha -1 ) to be applied from fertilizer FK 2 O = Potash (kg ha -1 ) to be applied from fertilizer T = Targeted yield (q ha -1 ) SN = Available nitrogen (kg ha -1 ) from the soil SP = Available phosphorus (kg ha -1 ) from the soil SK = Available potassium (kg ha -1 ) from the soil Cotton dibbled at 90 cm x 90 cm and chickpea was at 35 cm x 10 cm. The experimental plots were kept fixed over the years. All intercultural operations were done as and when required. In order to analyze the influence of soil properties on agronomic performance and to assess the impact of integrated nutrient management on soil fertility, representative soil samples were taken from experimental plot and initial soil status was assessed. Rest all the soil samples were taken at the end of second year cropping sequence. Samples were taken from the cultivated soil layer (upper 15 cm), using a single auger. The samples were air-dried, crushed, and gravel and other particles of size more size than 2 mm were removed with a sieve. Field moist soil was used for analyzing all the biological parameters. Data presented in Table 1, 2 and 3 are pooled mean of two seasons of cotton-chickpea cropping sequence. The statistical analysis of the experimental data was carried out as per the methods suggested by Gomez and Gomez (1983). RESULTS AND DISCUSSION Effect of INM on yield: Various nutrient management treatments influenced the summer seed cotton yield significantly. Application of RDF according to STCR equation

Volume 49, Issue 3, 2015 TABLE 1: Seed cotton yield, chickpea seed yield and cotton equivalent yield as influenced by various treatments (pooled mean of 2006-08). Treatments Seed cotton Chickpea seed Cotton equivalent yield(kg ha -1 ) yield(kg ha -1 ) yield (kg ha -1 ) Main plot treatments 10 t FYM ha -1 + RDF 2140 2441 4095 75 % RDF + 25 % RDN through VC 1835 1815 3291 50 % RDF + 50 % RDN through VC 1649 2124 3345 25 % RDF + 75 % RDN through VC 1422 2209 3193 100 % RDN through VC 1293 2393 3211 RDF according to STCR equation 2381 2120 4080 Control 1027 1422 2169 SEm+ 108 22.5 30 CD at 5 % 299 65.2 88 Sub plot treatments Control - 1537 2909 50 % RDF - 2029 3304 75 % RDF - 2319 3536 100 % RDF - 2416 3614 SEm+ - 17 11 CD at 5 % - 49 33 registered significantly higher seed cotton yield (2381 kg ha -1 ) and which was found at par with application of 10 t FYM ha -1 + RDF (2140 kg ha -1 ) which was followed by 75 % RDF + 25 % RDN through vermicompost (1835 kg ha -1 ). However lowest seed cotton yield was registered in control. FYM or vermicompost which are considered to be the good source of all plant nutrients and also the mineralization of organic nitrogen in FYM and vermicompost, which is a slow process, might have provided nitrogen during the crop requirement. Kaur et al. (2007) also opined the similar results for increased seed cotton. Effect of preceding summer seed cotton treatments have shown significant effect on succeeding chickpea crop. Application 10 t FYM ha -1 + RDF shown significantly higher yield of chickpea (2441 kg ha -1 ) and which was found at par with application of 100% RDN through vermicompost (2393 kg ha -1 ) to main plots. Application 50 % RDF + 50 % RDN through vermicompost (2124 kg ha -1 ) and RDF according to STCR equation (2120 kg ha -1 ) were at par with each other. However among sub plots significantly superior chickpea grain yield was registered to 100% RDF (2416 kg ha -1 ) followed by 75% RDF (2319 kg ha -1 ) and significantly lowest yield was observed in control. The increased chickpea grain yield might be due to addition of FYM and vermicompost to preceding summer cotton resulting in improvement in soil structure which reduced the soil crusting and also serves as a source of energy for soil microflora which resulted in better root nodulation and nitrogen fixation. These results are in conformation with those reported by Gawai and Pawar (2005). Significant improvement in cotton equivalent yield was observed due to various integrated nutrient management (INM) treatments to cotton and fertilizer levels to chickpea (Table 1). Highest cotton equivalent yield (4095 kg ha -1 ) among main plot was recorded by sole chemical fertilizer treatment RDF according to STCR equation and which was at par with treatment 10 t FYM ha -1 + RDF (4080 kg ha -1 ). INM treatment 75 % RDF + 25 % RDN through vermicompost (3291 kg ha -1 ) and 50 % RDF + 50 % RDN through vermicompost (3345 kg ha -1 ) were at par with each other. This was due to inorganic fertilizer application and slow and steady availalability of nutrient through vermicompost to cotton and its residual effect on chickpea. These results are in close agreement with the findings of Gawai and Pawar (2005). However among sub plot, application of fertilizer level 100% RDF recorded significantly higher cotton equivalent yield (3614 kg ha -1 ) followed by application of 75% RDF (3536 kg ha -1 ). Effect of INM on physical properties of soil: Bulk density of soil was not affected significantly both in main and sub plot (Table 2). In general, the effect of integrated application of organic and inorganic fertilizer and/or sole application of VC for nitrogen on bulk density was more pronounced than the sole application of inorganic fertilizer. Maximum reduction (1.33 Mg m -3 ) in bulk density was recorded in three treatments namely 10 t FYM ha -1 + RDF, 25 % RDF + 75 % RDN through VC, and 100% RDN through VC which is 2.2 % higher over control. This can be attributed to greater organic carbon content maintained as a result of continuous applications of FYM and VC. Santhey et al.

210 INDIAN JOURNAL AGRICULTURAL RESEARCH TABLE 2: Effect of integrated nutrient management on equivalent yield and physical properties of soil (pooled mean of 2006-08). Treatments Physical properties Bulk density Field capacity Permanent Hydraulic Infiltration (Mg m -3 ) (%) wilting point conductivity rate (%) (cm hr -1 ) (cm hr -1 ) Main plot treatments 10 t FYM ha -1 + RDF 1.34 40.87 24.15 1.64 1.02 75 % RDF + 25 % RDN through VC 1.36 39.75 26.05 1.43 0.94 50 % RDF + 50 % RDN through VC 1.35 39.82 25.29 1.54 0.95 25 % RDF + 75 % RDN through VC 1.34 40.52 24.87 1.57 0.99 100 % RDN through VC 1.34 40.82 25.10 1.67 1.03 RDF according to STCR equation 1.38 39.49 26.23 1.32 0.90 Control 1.37 39.45 26.07 1.34 0.91 SEm+ 0.02 0.3 0.1 0.01 0.01 CD at 5 % NS 0.9 0.3 0.03 0.03 Sub plot treatments Control 1.36 39.58 26.62 1.54 0.95 50 % RDF 1.36 39.71 26.31 1.52 0.93 75 % RDF 1.35 39.84 24.97 1.46 0.99 100 % RDF 1.35 39.90 25.11 1.37 1.01 SEm+ 0.03 0.23 0.09 0.01 0.01 CD at 5 % NS NS 0.27 0.03 0.03 Initial status 1.39 39.42 21.28 1.30 0.88 (1999) also reported reduced bulk density of soil resulting from application of organic manure in an INM experiment. The highest bulk density was observed by application of RDF according to STCR equation. No specific trend was recorded in sub plot treatments where different fertilizer levels were applied. Field capacity: Field capacity of soils varied from 39.5 to 30.87 % under various treatments but did not vary significantly where sole inorganic fertilizers were applied or where the quantity of organic manure lesser with inorganic fertilizers. The highest field capacity was observed by application of 10 t FYM ha -1 + RDF (30.87 %) and it was found at par by application of 100% RDN through VC (30.82%) and 25 % RDF + 75 % RDN through VC (30.52%). Change in structural condition of soil due to application of FYM and VC with inorganic fertilizer could be the possible reason, as reported by Gawai (2003). Soil field capacity is controlled primarily by the number of pores, their distribution, and specific surface area of soils (Saha et al. 2010). However field capacity did not vary significantly for various fertilizer levels to chickpea and it increased with increase in fertilizer levels. The highest field capacity was recorded by application of 100% RDF (39.90%). Permanent wilting point: Permanent wilting point of soil varied significantly from (Table 2) 15 to 26.62 % under various treatments. The highest permanent wilting point was recorded by control (26.07%) and was at par with application of 75 % RDF + 25 % RDN through VC. The lowest permanent wilting point was observed by application of 10 t FYM ha -1 + RDF (23.16%). The general observation from the data of permanent wilting point shows that, where ever application of organic manure solely or in combination with inorganic fertilizer was done there was reduction in permanent wilting point. This might be due to increase in the porosity of soil due to application of organic manures viz., FYM and VC to the INM treatments, as reported by Gawai (2003). Application of RDF levels to sub plots of chickpea varied significantly but did not shown any trend. Control has shown the highest wilting point (26.62%). Permanent wilting point shows its relation with field capacity. Application of organic manures solely or in combination of with chemical fertilizer shows higher difference than where chemical fertilizer application was done in sole or where organic fertilizer application was lower. This higher difference is useful for holding more capillary water (Gawai 2003). Hydraulic conductivity: Nutrient treatments had a significant effect on hydraulic conductivity of soil. Sole organic N source or application of organic with chemical fertilizers recorded maximum hydraulic conductivity (Table 2). Better aggregation and increased porosity is due to addition of organic manure which directly influenced hydraulic conductivity and ultimately soil water dynamics. The hydraulic conductivity under treatment 100% RDN through VC (1.67 cm hr -1 ) was 20.95% more than that in application of RDF according to STCR equation (1.32 cm hr -1 ), which was even lower than control (1.33 cm ha -1 ). In

Volume 49, Issue 3, 2015 this study hydraulic conductivity was enhanced due to continuous addition of organics solely or in combination with inorganic fertilizers as compared to inorganics alone (Saha et al. 2010). As soil permeability is a function of effective pore volume, increased pore volume has a direct influence on hydraulic conductivity of the soil. Subplots to chickpea was influenced significantly by addition of different fertilizer levels. Hydraulic conductivity was decreased with each increase of fertilizer levels, highest hydraulic conductivity was observed in control (1.52). Infiltration rate: The infiltration rate under different treatments was recorded after chickpea harvest (Table 2) which showed that cumulative infiltration varied from 0.90 to 1.03 cm hr -1. The highest cumulative infiltration (1.03 cm hr -1 ) was observed by application 100% RDN through VC, which was significantly higher over other treatments except 10 t FYM ha -1 + RDF. Application of 100% N through VC increased cumulative intake of water by 12.62% over RDF according through STCR equation (0.90 cm hr -1 ). All treatments receiving VC or FYM showed higher infiltration rate over control and application RDF through STCR equation, which recorded the lowest hydraulic conductivity. Hence it can be assumed that application organic fertilizers solely or in combination with chemical fertilizers increased the cumulative infiltration of water as compared to chemical fertilizers alone, which may be attributed to improvement in physical properties of soil. Walia et al. (2010) reported higher cumulative infiltration rate by application of 50% N through VC with combination of chemical fertilizers. However among sub plot treatments no specific trend was observed through the fertilizer levels though they were varied slightly. Effect of INM on chemical properties of soil Soil ph: The data presented in Table 3 revealed that, at the end of second sequence of chickpea crop, the ph of soil decreased in comparision to its initial status (ph 8.01). After chickpea harvest, the ph of the soil varied from 7.97 to 8.08. Soil ph tended to be the lowest (7.97) where 10 t FYM was added in combination of RDF. Substitution of 25%, 50%, and 75% RDN through VC did not register lower ph over initial status. However substitution of 100% RDN through VC registered minor change in ph and addition of 10 t FYM affected significantly than the other treatments. So application of FYM with chemical fertilizer and VC for sole N substitution decreased soil ph as compared with partial substitution of N through VC which may be attributed to production of organic acids during decomposition of organic manures. Gawai (2003) reported reduction in soil ph, due to microbial decomposition of organic manures. However in subplot control recorded the lowest ph (7.98) and 100% RDF level recorded the highest ph (8.07) which is higher than even initial stage ph. Electrical conductivity: The data indicated that electrical conductivity of the soil decreased under cotton-chickpea cropping sequence as compared to initial value of 0.28 ds m -1 (Table 3). After the harvest of chickpea, it varied from 0.26 to 0.32 ds m -1. The lower values ranging from 0.26 to 0.28 ds m -1 were observed in treatments where FYM and VC were applied in combination with chemical fertilizers or VC alone. Similar decrease in electrical conductivity has been reported by Walia et al. (2010) in an INM experiment on a rice wheat cropping sequence. Among sub plot treatments electrical conductivity increased with increase in fertilizer levels to chickpea. The lowest electrical conductivity was observed in control (0.27 ds m -1 ). TABLE 3: Effect of integrated nutrient management on chemical and biological properties of soil (pooled mean of 2006-08). Treatments Chemical properties Biological properties ph Electrical conductivity (ds m -1 ) Organic carbon (%) Available nutrients (kg ha -1 ) N P K Bacteria (CFU 10 4 g -1 soil) Fungi (CFU 10 3 g - 1 soil) Actinomycetes (CFU 10 3 g -1 soil) Main plot treatments GRDF (10 t FYM/ ha + RDF) 7.97 0.26 0.69 92.5 18.89 293.6 36.40 33.50 58.30 75 % RDF + 25 % RDN through VC 8.05 0.28 0.55 117.0 26.40 309.7 30.70 24.40 49.80 50 % RDF + 50 % RDN through VC 8.02 0.27 0.63 112.7 17.19 301.9 32.40 27.60 51.60 25 % RDF + 75 % RDN through VC 8.00 0.28 0.64 103.8 15.31 299.2 34.70 28.30 53.40 100 % RDN through VC 8.00 0.26 0.69 103.7 14.48 297.6 36.10 30.40 55.70 RDF according to STCR equation 8.04 0.32 0.49 108.7 23.48 293.0 24.60 25.10 47.20 Control 8.08 0.28 0.43 71.7 20.43 290.8 20.20 15.40 36.70 SEm+ 0.005 0.005 0.01 1.6 0.73 1.94 0.76 0.75 0.90 CD at 5 % 0.013 0.016 0.03 4.8 2.26 6.00 2.34 2.31 2.78 Sub plot treatments Control 7.98 0.27 0.55 114.3 21.58 303.0 32.18 27.67 45.62 50 % RDF 7.99 0.29 0.58 111.1 21.11 301.6 31.83 27.24 50.22 75 % RDF 8.05 0.28 0.55 101.1 19.47 298.1 30.20 26.14 52.41 100 % RDF 8.07 0.29 0.61 79.3 15.65 289.2 28.71 24.49 53.29 SEm+ 0.003 0.002 0.005 0.4 0.21 0.24 0.05 0.10 0.48 CD at 5 % 0.008 0.006 0.015 1.3 0.62 0.68 0.14 0.28 1.37 Initial status 8.01 0.28 0.52 168.33 13.46 467.33 17.7 22.6 30.6

212 INDIAN JOURNAL AGRICULTURAL RESEARCH Organic carbon: The maximum organic carbon build up varying from 0.63 to 0.69% was recorded by application of 100% RDN through VC, 10 t FYM ha -1 + RDF and 25% RDF + 75% RDN through VC. Substitution of 25% to 50% RDN through VC showed organic carbon values 0.55% and 0.63%, respectively. This might be due to build up of higher amount of organic carbon in the soil after harvest of the crop which is due to addition of higher biomass to soil. Organic carbon content of soil was improved in all treatments except control. Application of organic fertilizer and/ or combination with chemical fertilizer helped for building up of organic carbon. Sharma and Subehia (2003) also reported greater levels of soil organic carbon under integrated treatments of organic and inorganic combinations. Legume crop like chickpea add handsome crop biomass in soil. Among sub plot treatments application of different levels of fertilizers significantly varied organic carbon content of soil. The highest organic carbon content was recorded by application of 100% RDF to chickpea (0.61). Available N: The data presented in Table 3 for available N status indicate that the N status of the soil was found to be low as compared to initial value (168.3 kg ha -1 ). Maximum available N obtained was 117.0 kg ha -1 by application of treatment 25% RDF + 75% RDN through VC which was significantly higher over other treatments. However, it was closely followed by 50 % RDF + 50 % RDN through VC at 112.76 kg ha -1. The lowest value of available N (71.7 kg ha -1 ) was observed in the control plot. Hence, it is clear that application organic manures along with chemical fertilizers increased the available N soil, which may be attributed to mineralization of N from VC during decomposition. In sub plot treatments to chickpea significantly higher available N was recorded by control (113.3 kg ha -1 ) and lowest by application 100% RDF to chickpea, it means there was more mining of nutrients from directly available nutrient from fertilizer. Similar results have also been reported by Singh et al. (2001). Available P: The data presented in Table 3 indicate that the available P status of the surface soil improved significantly to 20.33 kg ha -1 in the control plot from its initial value of 13.36 kg ha -1 after harvest of second season of chickpea. However, the available P status of the soil continued to increase with addition of organic fertilizers alone and with their combined use with chemical fertilizer. Unlike from available N, available P increased in all treatments over initial available P. Application of 75 % RDF + 25 % RDN through VC treatment has substituted 25% RDF and helped to build up P status (26.30 kg ha -1 ) and was significantly higher than all other treatments which was followed by application RDF according to STCR equation. Therefore combination of organic manure with chemical fertilizer and sole addition of chemical fertilizer also helped in increasing the available P in the soil by mineralization or solubilizing the native P reserves. Among the sub plot levels to chickpea availability of P decreased with increase in fertilizer level. These results are in confirmation with ( Gawai 2003). Available K: Higher content of available K varying from 299.2 to 309.7 kg ha -1 was observed in treatments where VC was included with chemical fertilizers. Significantly higher available K was observed by application of 75 % RDF + 25 % RDN through VC over all other treatments. Treatments 50 % RDF + 50 % RDN through VC (301.99 kg ha -1 ), 25 % RDF + 75 % RDN through VC (299.2 kg ha -1 ) and 100 % RDN through VC (297.6 kg ha -1 ) were at par with each other. Maximum decrease in available K was recorded in control (290.8 kg ha -1 ) which is 37.7 % decrease over initial status (367.3 kg ha -1 ). Sub plot levels shown decrease of available K with increase in fertilizer levels. Decrease in available K might be due to immobilization or more nutrient uptake than supply of nutrients. Significantly higher available K was recorded in control (303.3 kg ha -1 ) and lowest in 100% RDF (289.2 kg ha -1 ). These results are in confirmation with Gawai (2003). Vertisols are generally rich in K content, and application of potassic fertilizers is not recommended in some pockets to these soils. Nevertheless, the importance of K in regulating and improving water functions in plant system and enabling the crop to withstand drought under rainfed conditions where intermittent dry spells are usual, cannot be undermined. Effect of INM on biological properties of soil: Under biological soil properties viable count of bacteria, fungi and actinomycetes was calculated. The microbial status of the soil under cotton-chickpea cropping system was studied at the end of second sequence. Data in Table 3 indicates that application of treatment 10 t FYM ha -1 + RDF and 100% RDN through VC, respectively gave the highest viable count of bacteria, fungi and actinomycetes ranging from (20.20 to 36.30) x 10 3, (15.30-33.50) x 10 3, and (36.70-58.30) x 10 3 cfu g -1 soil, respectively. The application of chemical fertilizers in sole in treatment RDF according to STCR equation produced low counts of bacteria (23.60 x 10 3 ), fungi (25.10 x 10 3 ), and actinomycetes (37.20 x 10 3 ) as compared to INM treatments and sole organic nitrogen treatment 100% RDN through VC. Control recorded lowest counts of bacteria (20.20 x 10 3 ), fungi (15.30 x 10 3 ), and actinomycetes (35.70 x 10 3 ). The reason behind the growth of microorganisms may be due to decomposition of added FYM and VC in soil which improved the physical properties of soil. As far as the sub

Volume 49, Issue 3, 2015 plots to chickpea are concerned there was decrease in microbial population as the fertilizer levels were increased except in the case of actinomycetes where, a negative trend was found. Maximum bacterial and fungal population was found in control at 32.18 x 10 3 and 27.67 x 10 3, respectively. However maximum population of actinomycetes was recorded by application of fertilizer level 100% RDF (53.29 x 10 3 ). Badole and More (2001) concluded that the population of Azotobacter, fungi, actinomycetes and bacteria were maximum with different combinations of organic sources i.e. FYM, glyricidia, vermicompost etc. in cotton and groundnut. Highest microbial population was recorded in integrated nutrient supply. Application of various organic manure sources for nutrient requirement compensation in combination with various fertilizer levels as a INM theme showed significant results on yield and physical, chemical and biological properties of soil in cotton chickpea cropping sequence. To sustain the high productivity of cotton chickpea cropping sequence in vertisols of western Maharashtra (Rahuri) is a representative area of Deccan plateau of India. From yield study of pooled mean of data of two years it is imperative to integrate RDF + 10 t FYM ha -1 or use STCR, a targeted yield equation. But for sustainable crop and soil management for future, use of INM approach is proved to be a safe avenue. Use of 75% RDF + 25% RDN through VC and 50% RDF + 50% RDN through VC recorded improvement in cotton equivalent yield and soil properties. Application of RDF + 10 t FYM ha -1 and 100% RDN through VC helped for improvement soil physical parameters viz. bulk density, field capacity, permanent wilting point, hydraulic conductivity and infiltration rate by improvement in soil porosity, soil chemical properties viz. soil ph, EC, organic carbon, available nutrients and soil biological properties were also improved due to organic compounds added to the soil in the form of FYM and VC which are preventing fixation, oxidation, precipitation, and leaching of nutrients and making it available for crop plant by chelating action. Addition of legume chickpea in the sequence also increased the sustainability of cotton chickpea cropping sequence. Fertilizer level 100% RDF significantly registered higher crop yield, but the fertilizer levels to chickpea were not really remunerative from soil properties point of view. REFERENCES Badole, S.B., and More S. D (2001) Effect of integrated nutrient management system on the changes in soil microbial population under cotton-groundnut cropping system. Journal of Indian Soc. of Cotton Improvement. 26(3): 83-87. Blaise, D., Majumdar G. and Tekale K. U. (2005) On-farm evaluation of fertilizer application and conservation tillage on productivity of cotton + pigeon pea strip intercropping on rainfed Vertisols of central India. Soil and Tillage Research 83:108 117. Gaur, P. M., Tripathi S., Gowda C. L. L., Ranga Rao G.V., Sharma, Pande H. C. S. and Sharma M. (2010) Chickpea Seed Production Manual. India: International Crops Research Institute for the Semi-Arid Tropics. Patancheru 502 323, Andhra Pradesh, pp. 1-28. Gawai, P. P. (2003) Effect of integrated nutrient management system in sorghum-chickpea cropping sequence. Ph.D. thesis submitted to M.P.K.V., Rahuri (M.S.) pp. 80-167. Gawai, P. P. and Pawar, V.S. (2005) Yield and yield components of sorghum (Sorghum bicolor) as influenced by integrated nutrient management system and its residual effect on chickpea (Cicer arietinum). Ann. Agric. Res., 26(3): 378-382. Gomez, K. A., and Gomez A. A. (1983) Statistical Procedure for Agriculture Research. New York: John Wiley & Sons. Hati, K. M., Mandal K. G., Misra, A. K., Ghosh P. K. and Bandyopadhyay K. K. (2006) Effect of inorganic fertilizer and farmyard manure on soil physical properties, root distribution, and water-use efficiency of soybean in Vertisols of central India. Bioresource Technol., 97: 2182 2188. Kaur, M., Kaur, M. and Brar, A. S. (2007) Effect of nutrients applied through organic and inorganic sources on the growth and yield of American cotton (Gossypium hirsutum L.). J. Cotton Res. Dev., 21(2): 194-196. Saha, R., Mishra V. K., Majumdar B. K., Laxminarayana and Ghosh P. K. (2010) Effect of integrated nutrient management on soil physical properties and crop productivity under a maize (Zea mays)-mustard (Brassica campestris) cropping sequence in acidic soils of northeast India. Comm. in Soil Sci. and Plant Ana., 31:2187-2200.

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