CHARACTERIZATION OF THE SOILS OF DROUGHT PRONE AREAS IN WAYANAD DISTRICT OF WESTERN GHAT REGION

Transcription

1 CHARACTERIZATION OF THE SOILS OF DROUGHT PRONE AREAS IN WAYANAD DISTRICT OF WESTERN GHAT REGION 1. Introduction Wayanad district formed by amalgamating south Wayanad of Kozhikode and north Wayanad of Kannur district falls in the Western Ghat tract. Till not very long ago, Wayanad had plenty of water with abundance of paddy fields. During , Sulthan Bathery block was very severely affected by drought. 85% of the cropped area was affected and 80% of the families affected. Net area sown as per statistics is 1,17,182 ha in the district. Extent under paddy fields has come down from 30,000.ha in 1980 to 12,995 ha in Today, the entire region is facing drought due to change in rainfall pattern, unchecked deforestation and large scale conversion of paddy fields into plantations. Agriculture production and productivity have been affected. The area and production under coffee has remained stagnant during to The area and production under pepper has declined by about 46 percent during the period. The district has not recovered from the droughts of recent years with dry spells continuing. The worst affected panchayats are Mullankolly, Pulpally and Irulam village of Poothadi panchayat Detailed studies are required to identify the extent of drought prone area in the district, their reasons thereof and possible management measures. The Planning & Economic Affairs (E) Department vide G.O.(M.S) No. 45/07/Plg. dated 23/10/2007 accorded sanction for a three year R&D project titled Characterization of the soils of drought prone areas in Wayanad district of Western Ghat region under Western Ghat Development Programme to Soil Survey Department with Dr.P.N.Premachandran, the then Additional Director, Soil Survey as Principal Investigator at a total cost of Rs lakhs. This study aims to identify, delineate and quantify drought prone areas in Wayanad district of the Western Ghat region with special reference to soils of the tract. Key drought indicators are studied including climatic parameters, ground water characteristics etc. Drought management measures are also discussed. Dept of Soil Survey & Soil Conservation...1

2 2. Objectives An assessment of the status of the natural resources of the tract with special reference to soils is essential to understand its potential and its limitations. This becomes important because plant water availability depends on prevailing weather conditions, biological characteristics of the specific plant, its stage of growth and the physical and biological properties of the soil. Drought is usually a period of prolonged dryness that causes extensive damages to crops. Being a function of climate, drought risk identification, zone delineation, and management studies also includes interpretation of climatic parameters and water availability. The objectives of the R&D project titled Characterization of the soils of drought prone areas in Wayanad district of Western Ghat region under Western Ghat Development Programme are listed below. 1. Detailed soil resource inventory of the drought prone areas in Wayanad district 2. Assessment of the morphological characters of the soils of the area 3. Assessment of the physico-chemical properties of the area 4. Assessment of the soil fertility of the area 5. Land capability and crop suitability of the soils of the area 6. Interpretation of the climatological data for drought prone assessment and management of the area Technical Programme 1. Acquisition of climatic data of the district for the past years 2. Collection of socio-economic, land use and ground water details 3. Analysis of the collected data to identify the drought prone areas of the district 4. Detailed soil survey and mapping of soil management units in selected areas after field review, soil correlation etc. 5. Examination of soil profiles, collection of soil profile samples and analysis of samples of typifying soil series 6. Collection of soil samples for soil moisture studies and fertility analysis 7. Physical and chemical analysis of the soil samples collected 8. Map and report generation Dept of Soil Survey & Soil Conservation...2

3 9. Analysis and interpretation of the data generated for practical application in land management and agricultural development in the drought affected areas 3. Location of the project area On the basis of base line surveys, the drought prone tracts in Wayanad district were provisionally identified. Mullankolly and Pulpally panchayats and Irulam village of Poothadi panchayat are selected for detailed drought characterization studies during the course of this R & D project. Mullankolly panchayat lies between to north latitude and to east longitude extending over 5548 ha. Pulpally panchayat extends over 8368 ha and lies between 11 o to 11 o north latitude and 76 o to 76 o east longitude. Irulam village of Poothadi panchayat lies between and north latitude and between and east longitude and extends over 5348 ha. The project area in total extends over ha and lies between and N latitude and between 76 o and 76 o E longitude. 4. Methodology & procedures Soil and land resource survey being essential to evaluate natural resource status of the project area, detailed soil survey is undertaken in Mullankolly, Pulpally and Poothadi panchayats. Irulam panchayat is demarcated from Poothadi panchayat after completion of survey. Key drought indicators like climate, ground water reservoir status, crop cultivation status are studied and drought management strategies developed Soil survey methodology Detailed soil survey was carried out following the procedure envisaged in the revised Soil Survey Manual. Cadastral maps of 1:5000 scale were used as base map for the survey. The whole area was traversed at close intervals. During the course of the traverse, the soils were subject to keen observation and examination and their differentiating characteristics were studied with respect to their capacity Dept of Soil Survey & Soil Conservation...3

4 to support plant growth. Profile pits up to a depth of 2 meters or up to the parent material were dug and the profiles were examined in detail for horizon-wise characteristics such as texture, structure, colour, consistency, concretions, mottling, soil reaction, pores, root distribution, permeability etc. The soil samples pertaining to each horizon were collected from profiles and sent to the laboratory for detailed analysis. On the basis of these observations and the supplementary laboratory analysis, the soils of the area were classified into soil series. The soil series along with their types and phases such as surface texture, thickness of solum, slope gradient and site characters like erosion, stoniness and gravelliness etc. were demarcated on the map as per the procedure in the Soil Survey Manual. Various combinations of these characteristics are classified as independent soil mapping units separated from each other by drawing soil boundaries on base maps. Soil mapping unit denotes name of soil series, surface soil texture, soil depth, slope and erosion status. These base maps were further processed and interpretative maps for soil land capability and irrigability, soil fertility, soil conservation priority areas and proposed land use were prepared. Digital data conversion is undertaken in the Geomatics Lab in the Arc INFO platform. Thematic maps, graphs etc prepared are attached Climatic data interpretation Decadal rainfall, temperature, relative humidity, wind velocity, evaporation collected from Coffee Board Liaison Office, Mullankolly, Regional Agricultural Research Station, Ambalavayal, Coffee estate Beenachi, Regional Coffee Research Station, Chundale are analysed and interpreted. Drought as an anomaly of climate is given due importance and various trends and patterns in climate are studied Mullankolly panchayat, Pulpally panchayat and Irulam village of Poothadi panchayat are border districts adjoining Mysore district in Karnataka State. The climate data collected from IMD stations in Mysore is also compared and interpreted Landsat imagery interpretation About Landsat: Landsat represents the world's longest continuously acquired collection of space-based moderate-resolution land remote sensing data. On July 23, 1972 the Earth Resources Technology Satellite was launched. This was Dept of Soil Survey & Soil Conservation...4

5 eventually renamed to Landsat. The most recent, Landsat 7, was launched on April 15, The instruments on the Landsat satellites have acquired millions of images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance, education and national security. Landsat 7 data has eight spectral bands with spatial resolutions ranging from 15 to 60 meters; the temporal resolution is 16 days. The nearly four decades of imagery provides a unique resource monitoring landscape change. The Landsat Program and the data it collects support government, commercial, industrial, civilian, military, and educational communities throughout the United States and worldwide. USGS and NASA collaborated on the creation of four Global Land Survey (GLS) sets from Landsat images: one from the 1970s, 1990s, 2000, and GLS permits the study of landscape change including: Land use change Deforestation/reforestation Urbanization Disaster assessment Glacier movement Water level change Landsat Images studied Vegetation changes during the project period in Mullankolly panchayat, Pulpally panchayat and Irulam village of Poothadi panchayat are studied by interpretation of the following imageries. Path 144, Row 52 Landsat-7-ETM+,L _ Path 145, Row 52, Landsat-7-ETM+, L _ Interpretation is both visual and in the ARCINFO GIS environment Water balance curve preparation Water balance curves are computed for bench Mark soils identified in the tract. The rainfall, evaporation and temperature data are collected from climatological Dept of Soil Survey & Soil Conservation...5

6 stations with the purview of the project. Potential evapotranspiration is calculated from evaporation data using Thornthwaite method. The classes identified are deficit, recharge, surplus, utilization, moist, humid and moderately dry. The soil moisture status is interpreted from the graph Groundwater data compilation Groundwater details of the State are generally evaluated once in 4 to 5 years. Available block-wise data on groundwater resources of the project area is collected from Central Groundwater board. Data is also collected from the Aquifer Atlas. Groundwater details collected during the conduct of soil health card programme in Mullankolly Pulpally and Poothadi panchayats is concatenated and ward-wise comparisons made Drought management strategies Though we have little control over climate and drought per se, the effect of drought can be minimized through better planning and management. Based on the available data on soil land and water resources of the project area, sustainable management measures can be worked out. The same is discussed Integration in the GIS environment Geospatial analaysis of the above pameters is undertaken in the Geomatics lab at the Directorate of Soil Survey and Soil Conservation in the ArcGIS ver 10 platform by the project team constituted for this purpose. 5. Soil and Land Resource Inventory of the project area The physico-chemical properties of the soil have an important role in how much water is stored, is available for plant growth and how a tract reacts to drought-like conditions. Detailed soil survey of Mullankolly panchayat, Pulpally panchayat and Irulam village in Poothadi panchayat is undertaken. 6. Results and discussion 6.1. Soil survey interpretation Dept of Soil Survey & Soil Conservation...6

7 The soil series encountered in Mullankolly panchayat are Edakkal, Vellaramkunnu, Pulpally, Anchukunnu, Kappiset, Kabinigiri, Kolavalli, Battuvady, Mullankolly and Nulpuzha series. Land capability classification studies show the major class as fairly good cultivable land (IVe) covering an extent of 2632 ha in the panchayat. IIIe class covers 1706 ha. 3t is the major land irrigability class covering 3255 ha and therefore has severe limitation for sustained use under irrigation. Most of the series fall in the hydrologic group C with moderately high run off potential. The crop suitability has been worked out mapping unit wise. Problems and suggestions in the tract is also discussed. In Pulpally panchayat, the series encountered are Mananthavady, Kappiset, Meenangadi, Tariode, Anchukunnu, Pazhassi, Pulpally, Vellaramkunnu, Cheeyambam, Kulathur, Battuvady, Puthurvayal, Kambalakkad and Nadavayal. The major land capability class encountered in the panchayat is IIIe (moderately good cultivable land) at 2287 ha. 3t is the major land irrigability class. Most of the series fall in the hydrologic group C with moderately high run off potential. The crop suitability has been worked out mapping unit wise. Problems and suggestions in the tract is also discussed. Detailed interpretation is presented in chapter 6.2 In Irulam village of Poothadi panchayat, Kalloor, Sulthan Bathery, Pulpally, Meenangadi, Muttil, Irulam and Battuvady series are encountered. Moderately good cultivable land i.e., IIIe is the major land capability class covering 1281 ha and 3t with 1281 ha, the major land irrigability class. Most of the series fall in the hydrologic group C with moderately high run off potential. The crop suitability has been worked out mapping unit wise. Problems and suggestions in the tract is also discussed. Detailed interpretation is available in chapter 6.3 The role of soil texture and structure in drought is studied in detail as hereunder. Drought effect on soil fertility is also assessed Role of soil texture and structure in drought A soil s texture and aggregation determine air and water circulation, erosion resistance, looseness, ease of tillage, and root penetration. In Mullankolly panchayat, percent of the area has sandy clay loam surface texture and percent, sandy clay. In Pulpally panchayat sandy clay (57.74 per cent) is the Dept of Soil Survey & Soil Conservation...7

8 predominant texture. Sandy clay loam (49.73 per cent) is the dominant texture in Irulam village of Poothadi panchayat. Pulpally is the dominant series in Pulpally and Mullankolly panchayats and Irulam series, in Irulam village of Poothadi panchayat. The clay content in Pulpally series varies from 20 percent in the surface to 45 percent down the profile. In Irulam series, the surface has per cent clay and varies down the profile to per cent. The significance lies largely in the different water-holding capacities of soils of different texture. The water holding capacity of clay loam soil is per cent and on clay increase, the WHC increases. The fraction of available water is in the range of in loamy and clayey textures. Hydro-physical properties of the bench mark soil, Pulpally series, have been evaluated at two vapor pressures. It is 29.1 per cent (33Kpa) and 16.3 per cent (1500 Kpa) at 0-22 cm depth, 27.6 per cent (33Kpa) and 14.6 per cent (1500 Kpa) at cm depth, 29.9 per cent (33Kpa) and 16.8 per cent (1500 Kpa) at 49-74cm depth and 25.0 per cent (33Kpa) and 13.9 per cent (1500 Kpa) at cm depths. Clayey soils retain water in its micropores for a longer period of time but once the moisture is lost, the soil begins to crack depending upon clay mineralogy which in this case is kaolinitic. However, while texture is an innate property of the native soil and does not change with agricultural activities, aggregation can be improved or destroyed readily through our choice and timing of farm practices. The level of organic matter also determines how much water a soil can hold. Soil scientists report that for every 1% of organic matter content, the soil can hold 60 litres of plant-available water per acre of soil down to one foot deep. In addition to holding water, organic matter also improves aggregation. However, the organic matter content in the major soils of the tract is not appreciable. It is a maximum of 3.62 per cent at a depth 22-49cm in Pulpally series and 2.47 per cent at 6-18cm depth in Irulam series. High aggregation, abundant surface mulch and a biologically active soil are keys to drought-proofing these soils. All the soils of the project area have sub angular blocky texture. The structure has not been affected in the soils of the tract as a result of drought except at the top of the parched soil which in combination with unscientific anthropogenic interventions, leads to erosion. An extent of ha (92 per cent of the total) is under moderate erosion in Mullankolly panchayat. In Pulpally Dept of Soil Survey & Soil Conservation...8

9 panchayat, ha (87 per cent of the total) is under moderate erosion and in Irulam village of Poothadi panchayat, ha (82 per cent) Effect of drought on soil fertility In Mullankolly panchayat, the following ranges of fertility are seen among the identified soil series. Edakkal series has medium high nitrogen, low phosphorus and low medium potassium. Vellaramkunnu series has medium high nitrogen, low high phosphorus, and low high potassium. Pulpally series has low high nitrogen, low high phosphorus and low high potassium. Anchukunnu series has medium high nitrogen, medium high phosphorus and low high potassium. Kappiset has medium nitrogen, high phosphorus and medium potassium. Kabanigiri series has low high nitrogen, low high phosphorus and low high potassium. Kolavalli series has medium high nitrogen, low high phosphorus, low high potassium. Mullankolly soils have low high nitrogen, low high phosphorus and low high potassium. Battuvady series has medium high nitrogen, low high phosphorus and low high, potassium. Nulpuzha series has medium high nitrogen, high phosphorus and medium high potassium. In Pulpally panchayat, the following soil fertility ranges are observed. In Mananthavady series, nitrogen is high, phosphorous is low-high and potassium is high. Kappiset series has high nitrogen, medium to high phosphorous and low to medium potassium. In Meenangadi series, nitrogen is high, phosphorous is low-high and potassium is low-medium. Tariode series has high nitrogen; phosphorous is high, and potassium is high. In Anchukunnu series, nitrogen is high, phosphorous is high, and potassium is high. Vellaramkunnu series has medium to high nitrogen and phosphorous and low to medium potassium. In Pazhassi series, nitrogen is high, phosphorous is medium-high and potassium is low-high. In Pulpally series, nitrogen is medium-high, phosphorous is low-high and potassium is low-high. Cheeyambam series has high nitrogen, low to high phosphorous, and low to medium potassium. In Kulathur series, nitrogen is high, phosphorous is low to high and potassium is high. Battuvady series has high nitrogen, low to high phosphorous and potassium. In Puthurvayal series, nitrogen is medium-high, phosphorous is low to high and potassium is low-high. Kambalakkad series has high nitrogen, phosphorous Dept of Soil Survey & Soil Conservation...9

10 potassium. In Nadavayal series, nitrogen is high, phosphorous is high and potassium is high. In Irulam village of Poothadi panchayat, Kalloor series has medium-high nitrogen, phosphorous is high and potassium is medium. In Sulthan Bathery series, nitrogen is high, phosphorous is high, and potassium is low- medium. Pulpally series in Irulam village has medium-high nitrogen, medium-high phosphorous and potassium is low- medium. In Meenangadi soils, nitrogen is high, phosphorous is medium-high and potassium is low-medium. Muttil has medium-high nitrogen, phosphorous is medium-high and potassium is low to high. In Irulam series, Nitrogen is low- high, phosphorous is low- high and potassium is medium. Battuvady series has medium nitrogen, phosphorous is high and potassium is medium. Only three soil fertility classes-low, medium and high are recognized. Since fertility range of most of the soil series fall in one or two ranges, effect of drought on soil fertility can be assessed only if studies are repeated by taking samples from the same geographic location LANDSAT imagery interpretation Variability in ground vegetation in Mullankolly panchayat, Pulpally panchayat and Irulam village in Poothadi panchayat are studied using the following imageries - Path 144, Row 52 Landsat-7-ETM+, L _ and Path 145, Row 52, Landsat-7-ETM+L _ Stressed vegetation has a higher reflectance than healthy vegetation in the visible ( microns) region and lower reflectance in the near infrared ( microns) region of the electromagnetic spectrum. Vegetation indices take the advantage of this differential response in the visible and near infrared regions of the spectrum. Vegetation variability studies for and indicate that vegetation decrease is more pronounced in the latter indicating a possible vegetation decrease during the period. NDVI change studies from 2005 to 2010 shows a marked reduction in greenness in the tract. The extent of vegetation decrease during the period is ha. Dept of Soil Survey & Soil Conservation...10

11 Vegetation decrease is pronounced in Pulanad, Changadivayal, Manalvayal, Udayakara, Pakkom, Mailadi, Illyambamkudi, Kandamala, Kappikunnu etc in Pulpally panchayat are portions bordering Pulpally and Panamaram panchayat near Pasri reserve forest. In Irulam village the effect is spread towards the northern portion, Parts of Mullankolly panchayat and Irulam village bordering Kurchiyat reserve forest shows vegetation decrease. Overlay of image map with data of shows that this reduction in vegetation is during the later part of the decade. In Mullankolly panchayat, Vettathur, Alattur and northern portions bordering Karnataka shows the same effect. Drought indications are seen in Varavur, Dawapara, Dippo, Kabinigiri, Madal, Edamala, Padichira, Chelor, Marakadavu, Kolavally, Sitamount, Chamapara, Sasimala, Kadambur, Pattanikoop, Padiri, Channothukolly and Perikalloor in Mullankolly panchayat. Drought can favourably be assumed to be one of the reasons for vegetation decrease in these areas Climatic interpretation The unique topography of Wayanad is responsible for a distinct climate in Wayanad that is quite distinct from the climate of neighbouring regions. It is responsible for a strong gradient in rainfall within the district as well. The primary rainfall season of the region is during the south-west monsoon period. Moistureladen winds rush into Wayanad through the Thamarassery ghat pass in the southwest of Wayanad, which in turn receives copious amounts of rainfall thanks to orographic lift (Simon and Mohankumar, 2004). This phenomenon is so severe on the pass that the hill-top location of Lakkidi is one of the wettest locations in India. A changing climate leads to changes in the frequency, intensity, spatial extent, duration, and timing of extreme weather and climate events, and can result in unprecedented extreme weather and climate events. Changes in extremes can be linked to changes in the mean, variance, or shape of probability distributions, or all of these. Comparison of rainfall statistics of Wayanad district for the project period shows that in (from July 2006 to June 2007), rainfall in Wayanad district was 30 percent less than the normal. This was then the highest departure from normal in the State. In , the departure in rainfall was 11 Dept of Soil Survey & Soil Conservation...11

12 percent (deficient) from the normal. In (from July 2008 to June 2009) there was a deficiency of 43 percent departure from the normal rainfall. In (from July 2009 to June 2010) the deficiency in rainfall as compared to normal was 17 percent. The last time the district received normal rainfall was in ((from July 2005 to June 2006) when the total rainfall was 14 percent more than the normal. In short the district has not recovered from the effects of drought during the period of study. The Pulpally panchayat Vikasana Rekha, 1997 reports that the climate of Pulpally panchayat is different from other parts of Wayanad with more droughts and less rains, a condition comparable to that of neighbouring Mysore plains. Climatic data interpretation of four stations representing the climate of the tract was undertaken during the project period. Climatic data from Junior Liaison Office of the Coffee Board at Mullankolly, Regional Agricultural Research Station, Ambalavayal, Coffee estate, Beenachi and Regional Coffee Research Station, Chundale were interpreted and the findings are given below. Rainfall A study of rainfall status during the calendar year with special stress on the south east and north east monsoons indicate the following trends. Data for calendar years for the period 2000 to 2011 collected from Junior Liaison Office of the Coffee Board at Mullankolly reveals that lowest annual rainfall was in 2002 at 984mm. The highest rainfall was in 2004 at 2197 mm. During the project period of 2007 to 2010, the highest rainfall was in 2009 at 1657mm and lowest in 2007 at 1252 mm. During 2008 the annual rainfall was 1365mm and during 2010, 1551 mm. An analysis of the data also shows that only 22 percent is contributed by the north east monsoon during September to November. 19 per cent of the rainfall is received during April-May. In 2007 the annual rainfall in Kerala was surplus at +20 from the normal. In Wayanad district, annual rainfall was 3093 mm. In the district, the departure in rainfall from the normal in 2007 during the months of June, July and August was - 28, -1 and -8 respectively. During the north east monsoon in 2007 in Wayanad district during September, the surplus rainfall was at The annual rainfall during the year at the Station was low at 1252 mm. The high rainfall of September Dept of Soil Survey & Soil Conservation...12

13 in the district was not felt in Mullankolly area which recorded 95 mm during the month. In 2008, rainfall in Kerala was deficient by -20 per cent. In Wayanad district, the annual rainfall was 2142mm. The departure in south west monsoon from the normal was - 51 percent. During the north east monsoon period, the departure from normal rainfall during the months of September, October and November 2008 was -39, +117 and -88. Data on rainfall at the station revealed that south west monsoon contributed 45 per cent of the total rainfall in the calendar year and north east monsoon, 26 percent. 29 per cent of the total rainfall was contributed by pre monsoon showers. The project tract received only 185mm rainfall in October 2008 unlike the rest of the district. In Kerala, during 2009 the departure of annual rainfall during the south west monsoon was -9 from the normal but was +6 from the normal during the north east monsoon. In Wayanad district, during 2009 the deviation in rainfall from the district normal in June was -55, +8 in July and -71 in August, the three months which make up the south west monsoon period. During the north east monsoon period, the percentage departure of rainfall from the normal was +99 in November During December, the departure per cent was During 2009, the north east monsoon and rains in the succeeding months more than made up for a deficit in south west monsoon. In the project area, the rainfall trends were reversed. The month of June had highest rainfall at 662mm. Also, the south west monsoon contributed 57 percent of the total annual rainfall during This is also an indication that trends in the district cannot be generalized and spatial variations are seen in climate as in the project area. During 2010, in Kerala, the departure of south east monsoon was -10 from the normal. The north east monsoon during 2010, as in the previous year, exceeded the normal by +66. In Wayanad district during 2010, the deficit in rainfall in south east monsoon in Wayanad district was -52 (-46 departure from normal rainfall in June, -58 in July and -54 in August) while the north east monsoon was normal (percentage departure of received rainfall during November 2010 in Wayanad district was +113). During 2010, the annual rainfall at the Station was 1551 mm. Of this, 46 percent of the rainfall is contributed by south west monsoon and 32 percent by north east monsoon. 21 percent was contributed by premonsoon Dept of Soil Survey & Soil Conservation...13

14 showers in April and May of that year. The project area received only 141mm rainfall during November 2010 as against heavy rains in other parts of Wayanad district. Decadal rainfall studies from 2000 at the Regional Agricultural Research Station, Ambalavayal reveals that the lowest annual rainfall was in 2002 at 1109 mm similar to trends at Junior Liaison Office of the Coffee Board at Mullankolly and highest in 2005 at 2168mm. From 2007 to 2010 period, the highest value of 2077mm was experienced during 2009 similar to trends at the above station at Mullankolly. The lowest rainfall was during 2008 at 1731 mm. Month wise, maximum rainfall is experienced in July, followed by June. In 2007 as per RARS, Ambalavayal data, the annual rainfall is 2023mm, 64 percent of which is contributed by south west monsoon. 23 per cent is contributed by the north east monsoon. A rainfall of 262mm only was received in September 2007 during north east monsoon at the Station when the surplus rainfall in the district was at Trends in the district are not seen in the tract represented. In 2008, the annual rainfall in the project area was 1731 mm. The departure in south west monsoon from the normal in the district was - 51 per cent. Of the total rainfall received on site, 50 percent is contributed by south west monsoon and 29 percent by north east monsoon. October 2008 showed high rainfall at percent departure from the normal in the district which was reflected in the high rainfall of 402 mm during thee same month in the area represented by the Research Station statistics shows that the annual rainfall at RARS, Ambalavayal was 2077mm. 60 percent of the rainfall is contributed by south west monsoon and 25 percent by north east monsoon. In Wayanad district, during 2009, the deviation in south west monsoon from the district normal was -55 percent. During the year at the Station, the highest monthly rainfall was in July followed by November. The abnormally high percentage departure in rainfall in December 2009 monthly rainfall (+184 per cent) is not reflected in the tract which received only 35 mm rainfall. On analyzing 2010 trends, the total rainfall during the calendar year at RARS, Ambalavayal is 1852mm. 54 percent of rainfall is contributed by south west rainfall. 29 per cent is contributed by north east monsoon. During November 2010, Dept of Soil Survey & Soil Conservation...14

15 the district had a rainfall excess of This district trend was not seen in the tract. During the period, the rainfall in the project area represented was 280mm. Rainfall data from Beenachi Coffee estate indicate that the lowest rainfall was in In 2007, the annual rainfall is 2211mm and 1951 in Among the three blocks in the district, Sulthan Bathery (under which the project area falls) has the least number of rainy days and, Kalpetta, the maximum. The reverse is the case in area under rainfed cultivation. The effects of drought in Wayanad district upto 2010 period have not been mitigated during the succeeding years when the percentage departure in annual rainfall during south west monsoon was -25 and during north east monsoon, +8. Even during the period when rainfall was in excess in the district, the project area has received anomalously low rainfall. The rainfall pattern in the tract thus does not follow the district averages. The annual rainfall in the tract is much lower. Some areas bordering Karnataka state experience lower rainfall and identified as rain shadow region. Mullankolly, Pulpally, Tamitheruvu, Kappiset, Padichira and nearby areas come under rain shadow areas. A study on the climate of the project area will not be complete without an assessment of the climate in the neighbouring Karnataka since both occupy the Deccan plateau. To check whether the arid influences of the border district of Karnataka is extending towards Wayanad district in Kerala, the climate details of both the districts for the project period are compared. The results are as shown below. It is also established that the rainfall received during south west monsoon in Wayanad district as a whole is 3-4 times more than that in Mysore state. In the project area where the rainfall trends do not follow the district rainfall pattern, (Source data from Coffee Board Liaison Office, Mullankolly), the annual rainfall of 1252mm (2007), 1365mm (2008), 1657 mm (2009) and 1551 mm( 2010) are closer to the corresponding values of Mysore district. This shows that the arid zone is slowly spreading to the south western part of the Deccan plateau. In order to undertake further detailed climatic analysis in the tract, it is imperative to establish more rain gauge stations within the project area to monitor the precipitation levels. Dept of Soil Survey & Soil Conservation...15

16 Temperature Increased temperatures result in higher evaporation from the earth s surface and made the drought more intense. Scientific studies indicate that increased temperatures will result in decreased productivity. The decade starting from 2000 was the warmest ever. In the country, the annual temperature for the year 2010 was C above average, thus making the year 2010 the warmest year on record since It is argued that continuous rise in temperature in Wayanad district has made the district unsuitable for crops like orange which are on the decline. As per statistics of the Regional Agricultural Research Station, Ambalavayal, from 2000 to 2011, the maximum temperature varies from an average of C to C and minimum temperature varies from an average of C to C. The mean annual temperature for the period from 2000 to 2011 is highest in 2010 at C. The lowest mean annual temperature is in 2007 at C. The maximum temperature is found to be highest during the summer months of March, April and May and lowest in the rainy months of June, July and August. The annual minimum temperature varies from C (lowest in 2007) to C (highest in 2010). The mean minimum temperatures are lowest during December and January during most of the years. During the project period, the highest value for maximum temperature was observed in March 2010 at C and the highest value for minimum temperature also in the same year at C. In the project period, the mean annual temperature was highest during April. Relative Humidity Relative humidity was evaluated at the Regional Agricultural Research Station, Ambalavayal at two different time zones, 7.30 AM and 2.30 pm. From 2000 to 2010, the average relative humidity at 7.30 am was highest in 2005 at per cent. The lowest value was in 2011 at percent. The noon relative humidity is comparatively lesser with the lowest in 2011 (64.15 percent) and highest in 2006 (81.49 percent). The average relative humidity compiled from the above values shows highest values during 2007 at percent and lowest in 2011 at per cent. During the project period of 2007 to 2010, the highest average RH was experienced during 2007 (90.5 %) and lowest in 2009 at per cent. High humidity is reported to reduce evaporation loss but pest and disease incidences are Dept of Soil Survey & Soil Conservation...16

17 higher. RH together with air temperature and the solar radiation intensity affects the rate at which water is evaporated from the leaves of the plants. If the evaporative demand is too high, that is, if the roots and duct system of the plant cannot deliver water to the leaves, the plant responds by partially or totally closing its stomata. At higher RH percentages, the stomata have problems getting rid of excess water. At a lower RH, the stoma keep releasing water until the plant dries out. At that moment, the stomata close. Then, the intake of carbon dioxide stagnates, and plant growth is impaired. Wind speed A study of wind speed at the Regional Agricultural Research Station, Ambalavayal from 2000 to 2011 shows that on an average it is 3 km/hr. The lowest wind speed was experienced in 2003 at 2.79 km/hr and highest, 3.56 km/hr in On checking the wind speed during the rainy seasons in the project period, it is seen that the wind speed is 3.5 km/hr during the south west monsoon in In 2010, the wind speed during the period is 3.3 km/hr whereas it is 2.8 km/hr in 2007 and 2.7 km/hr in During the north east monsoon, the wind speed is highest in 2009 at 3.7 km/hr and lowest in 2007 at 2.6 km/hr. Evaporation Evaporation studies from 2001 to 2011 at Regional Agricultural Research Station, Ambalavayal shows that it is lowest during 2010 (when the average relative humidity percent at 7.30 am was 94.19) at 2.61mm and highest during 2009 at 3.09mm (the mean relative humidity is per cent). The values as expected are lowest during the south west monsoon period followed by north east monsoon period Groundwater interpretation The net groundwater availability in Wayanad district has come down from MCM in 2005 to MCM in The gross groundwater draft during the period was MCM and MCM. Groundwater is a principal source of irrigation and for domestic and industrial use especially in the panchayats of Mullankolly, Pulpally and Irulam village. Coffee farmers depend on ground water to make coffee blossom. The groundwater draft for all uses in 2005 is MCM in Dept of Soil Survey & Soil Conservation...17

18 Sulthan Bathery block. Anomalies in precipitation lead to over exploitation of these groundwater resources. As per the latest groundwater aquifer studies (Aquifer Atlas, 2012) Banded Gneissic Complex is the principal aquifer system in Wayanad district accounting to 71.5 percent of the total distribution of principal aquifer systems followed by charnockites at 15.7 percent. In BGC, the premonsoon depth to water level was minimum 1.7 m below ground level and maximum at 18m. In charnockites, the values were 1.4m (min) and 17.5m (max). The post monsoon values are 0.82m (min) and 15.15m (max) in BGC and 1m (min) and 16.32m (max) in charnockites. The decadal mean values ( ) for premonsoon for BGC is 1.65m (min) and 17.99m (max) and 1.35m (min) and 19.02m (max) for charnockites. For post monsoon, decadal mean values for BGC are 0.71m (min) and 16.06m (max) and for charnockites, 0.75m (min) and 15.94m (max). Weathered charnockites have been reported as poor aquifers. Water table elevation in the charnockites aquifer is averaged 732.5m (min) and 849.7m (max). Under BGC, the area suitable for groundwater development is 1,52,400 ha in Wayanad district. The project area predominates in charnockites type of rocks though schist s are also seen. The stage of groundwater development in the district is percent in 2005 and 17 percent in 2009 (the latter, the lowest in the State). Presently Sulthan Bathery block is categorized for future groundwater development as semi critical. Ratio of wells that dry up during summer is highest in Pulpally panchayat followed by Mullankolly panchayat. In Sulthan Bathery block, 4040 wells dry up during summer as per recent figures. Of this, 457 wells (ratio to open dry wells, 0.35) are in Mullankolly panchayat, 411 in Pulpally panchayat (ratio, 0.21) and 664 wells in Poothadi panchayat (ratio 0.27). The recharge component has been reduced due to land reclamation and change in land use pattern. Natural water sinks are being reclaimed. Wards showing lowering of groundwater levels are 3,11,15 in Mullankolly panchayat, 2,3,4,11,15 in Pulpally panchayat and 1,2,4,5,15 in Poothadi panchayat (Irulam village). This is a clear indication of drought in these panchayats. Between 2009 and 2010, however the change in groundwater levels is not substantial. Seasonal fluctuation of the water table is due to variation in the rainfall, evapotranspiration, withdrawals for irrigation and other purposes, base flow, seepage from surface water bodies etc. Dept of Soil Survey & Soil Conservation...18

19 The main source of groundwater resources is recharge from rainfall which contributes about 82 percent of the total replenishable resources. This means that groundwater resources are not sustained in case of lower than normal rainfall. Depth to water level is comparatively deeper in places bordering Karnataka State. These areas receive low rainfall and water level fluctuations are high. It is also suggested that geological fissures in the rock type in the tract permits easy flow-through rather than acting as aquifers. The heavy mining and dislocation of huge hills presently being carried out locally may even disturb the delicate structure and balance of tectonic plates resulting in heavy landslides and earthquake tremors. This can lead to groundwater dislocation or weaken the basement of constructions. A comparison of hydrographs of Pulpally, Mullankolly and Poothadi panchayats reveal that water level is lowest in Irulam village (Poothadi panchayat) and highest in Pulpally panchayat. There is limited scope for groundwater development in the tract which comes under Sulthan Bathery block classified as semi critical. The artificial recharge schemes suggested by CGWB are gully plug, desilting and renovation of ponds and tanks, subsurface dykes check dams etc Available water content and Water balance curves The major soil series in Pulpally panchayat which extends over 54.4 percent is Pulpally series. In Mullankolly panchayat, Pulpally series extends over 62.1 per cent. Irulam series extending over 32.5 per cent in Irulam village of Poothadi panchayat covers the major extent. Pulpally series is classified under Fine, mixed, isohyperthermic, Oxic Haplustepts and Irulam series under Clayey, mixed, isohyperthermic Typic Haplustults. The grouping under soil moisture regime is an attempt to indicate the extent of naturally available water in the soil depth of maximum root proliferation. In both these soil series, the soil is moist in some part of the moisture control section for more than 180 cumulative days per year which classifies the moisture regime as Ustic. There is one rainy season of three months or more. Its concept is one of moisture that is limited but is present at a time when conditions are suitable for plant growth. Mean summer and winter Dept of Soil Survey & Soil Conservation...19

20 temperatures differ by less than 6 C at a depth of 50cm or at a densic, lithic, or paralithic contact, whichever is shallower. The mean annual soil temperature is 22 C or higher. This puts these soils in the isohyperthermic temperature regime. Both the moisture regime and temperature regime are general groupings under the soil taxonomic classification system. The plus point however is the fact that the soil profile is studied upto to the depth of the parent material. The water balance curves prepared for Bench Mark Soils in the tract are given below. In Pulpally series, upto April, when rainfall is less than PET, soil moisture is deficit. April-May period is when PET breaks even with rainfall. From May onwards, with the rains, recharge of soil moisture occurs. In July highest rainfall is received and moisture is surplus. During this period, the soil first becomes moist and then humid. Even though the rains during north east monsoon are comparatively lesser, till November, the moisture is surplus. From November beginning when the rainfall goes below the PET till November end crops are able to utilize the available moisture ( Moderately dry ). Thereafter from mid November, moisture stress reappears. The Available Water Capacity of Pulpally series is estimated as 150mm/m In Mananthavady series, upto May, the PET exceeds rainfall and soil moisture is deficit. May beginning to May end with rains, recharge occurs. This is the period when soil is moist. Thereafter moisture is surplus till October end (soil is humid). November beginning to November end is time for utilization of available soil moisture (moderately dry). Thereafter by November end, deficit reappears. The Available Water Capacity of Mananthavady series is estimated as 180mm/m. This is the highest among the bench mark soils in the tract. For Meenangadi series, the Available Water Capacity is estimated as 117mm/m. Upto April, the moisture is deficit. April-May is the recharge period with the receipt of summer showers. Soil is moist during the period. From May to November when Rainfall exceeds PET and moisture is recharged, the moisture becomes surplus. Moisture status then is humid. From November beginning to November end, soil moisture status is moderately dry and it is reserve moisture utilization time. Thereafter, moisture is deficit. Dept of Soil Survey & Soil Conservation...20

21 In the case of Sulthan Bathery series (as given below), it is seen that moisture is deficit upto the end of April- beginning of May. From April onwards to May, PET values are on par with rainfall received and thereafter with the start of the rainy season after recharge, moisture becomes surplus. November beginning to November end with cessation of north east monsoons, the moisture in the soil is utilized by crop plants. From November end onwards, the moisture status is deficit. The Available Water Capacity of Sulthan Bathery series is estimated as 130mm/m. While water balance curves are specific to a series, it is also dependent on climatic observations of rainfall, temperature and evaporation. The site of the met station is therefore crucial in the preparation of AWC graphs. Moreover the entire area represented by one rainfall zone is taken a one unit and one graph drawn Trends in crop cultivation In Wayanad district, the major crops cultivated are paddy, pepper, arecanut, banana, coconut, tea, coffee and rubber. During the period from to , the area under paddy has increased by about 9 percent. Coffee area has remained more or less static. The agro ecological zone identified in the project area comprising of Mullankolly and Pulpally panchayats and Irulam village of Poothadi panchayat has a pepper based cropping system and there has been a significant reduction in area in pepper. The area has come down by 55 percent in the district. The district-wise area also shows the same trend. Rubber area has increased in the district from 5,02,240 ha in to 5,25,408 ha in The first showers of the year start around the middle of February. This is a crucial shower for three major crucial operations: First, the transplanting of paddy from nurseries for the summer crop of paddy; second, the onset of flowers blossoms of the coffee crop; and third, the planting of root crops. An inch (about 25 mm) of rain in a day is an ideal blossom shower. If followed promptly by backing showers after nine days two weeks, then the coffee beans are set and a fruiting occurs in proficient manner, promising a high yield of coffee beans in the coming year. However, blossom showers are often elusive, and its failure takes a heavy toll of the coffee crop and on agriculture on the whole. In order to Dept of Soil Survey & Soil Conservation...21

22 overcome this uncertainty, plantation and large coffee growers resort to using sprinklers in a timely manner, to make up for deficient blossom showers, groundwater resources permitting. From the middle of April, pre-monsoon showers become ubiquitous. The pre-monsoon showers are important for the growth of crops plants in February. Paddy crop reaches stage of tillering, and are highly dependent on adequate availability of water. Any delay in the rains reduces the yield, and can also push the harvest time to later. If the summer harvest overlaps with the onset of the south-west monsoon, heavy losses to crop yield are sustained because of an inability to harvest them. The arrival of south west monsoon happens in the first week of June. By the middle of July, most of the wetlands would have undergone a complete transformation from muddy flats to green paddy fields. Usually a break in the monsoon occurs around, July, where the region enjoys about a week of sunny weather. By the end of August and early September, the intensity of rains comes down drastically, gaining the consistency of a fine thread, referred to as Nool Mazha. It is an ideal time to apply manure, so that the tillering stage of the growing plants, will have grains that filled. By the middle of October, the north-east monsoon makes its appearance. The rains give the necessary moisture to the standing paddy crop, whip would be in advance stage of tillering. A strong north east monsoon allows the coffee crop to better endure the winter dry period. Usually at the end of the strong rains spells in late October and early November, coffee growers add fertilizer to the base of the coffee plant, which if applied correctly, provides partial resistance of the coffee plant to a below- normal blossom shower the next February. There has been a steady decline in production and productivity of pepper in the district as a whole and also in the project area. Extensive conversion to rubber plantations, diseases like Phythophthora foot rot, viral diseases, predominance of senile and uneconomic vines and climatic anomalies have been attributed for the fall in productivity. The productivity of pepper has declined from 284 kg/ha in to 221 kg/ha in Spices Board, India recommends an annual rainfall of 2000 mm with uniform distribution as being ideal for pepper. Delayed onset of monsoon with scanty rainfall will be a curse for pepper crop as pollination will be affected leading to drastic reduction in pepper production. Rainfall of 70 mm received in 20 days during May-June is sufficient for triggering off flushing and Dept of Soil Survey & Soil Conservation...22