LAND RESOURCE INVENTORY FOR WATERSHED PLANNING AND DEVELOPMENT YADGIR RF-7 (4D5B1C2a) MICROWATERSHED Yadgir Taluk and District, Karnataka

Abstract

The land resource inventory of Yadgir Rf-7 Microwatershed was conducted using village cadastral maps and IRS satellite imagery on 1:7920 scale. The false colour composites of IRS imagery were interpreted for physiography and the physiographic delineations were used as base for mapping soils. The soils were studied in several transects and a soil map was prepared with phases of soil series as mapping units. Random checks were made all over the area outside the transects to confirm and validate the soil map unit boundaries. The soil map shows the geographic distribution and extent, characteristics, classification, behavior and use potentials of the soils in the microwatershed. The present study covers an area of 473 ha in Yadgir taluk & district, Karnataka. The climate is semiarid and categorized as drought-prone with an average annual rainfall of 866 mm, of which about 652 mm is received during south-west monsoon, 138 mm during north-east and the remaining 76 mm during the rest of the year. An area of 179 ha in the microwatershed is covered by soils and about 294 ha by rock outcrops. The salient findings from the land resource inventory are summarized briefly below.  The soils belong to 1 soil series and 1 soil phase (management units) and 1 land management unit.  The length of crop growing period is about 120-150 days starting from 1st week of June to 4th week of October.  From the master soil map, several interpretative and thematic maps like land capability, soil depth, surface soil texture, soil gravelliness, available water capacity, soil slope and soil erosion were generated.  Soil fertility status maps for macro and micronutrients were generated based on the surface soil samples collected at every 320 m grid interval.  Land suitability for growing 29 major agricultural and horticultural crops was assessed and maps showing the degree of suitability along with constraints were generated.  Entire area in the microwatershed is suitable for agriculture.  Entire cultivated area of the microwatershed has soils that are very shallow (<25) in depth.  Entire cultivated area of the microwatershed has sandy soils.  Entire cultivated area of the microwatershed has gravelly (15-35%) soils.  Entire cultivated area of the microwatershed is very low (<50 mm/m) in available water capacity.  Entire cultivated area has very gently sloping (1-3% slope) lands in the microwatershed.  Entire cultivated area of the microwatershed has moderately (e2) eroded lands.  About 19 per cent area is moderately alkaline (pH 7.8-8.4), 17 per cent area is slightly alkaline (pH 7.3-7.8) and 2 per cent is neutral (pH 6.5-7.5) in soil reaction.  The Electrical Conductivity (EC) of the soils in the entire cultivated area of the microwatershed is dominantly <2 dsm-1indicating that the soils are non-saline.  An area of about 1 per cent of the microwatershed is low (<0. 50%) and 37 per cent is medium (0.50-0.75%) in organic carbon content.  Entire cultivated area of the microwatershed has soils medium (23-57 kg/ha) in available phosphorus.  Entire cultivated area is medium (145-337 kg/ha) in available potassium in the microwatershed.  Available sulphur is medium (10-20 ppm) in the entire cultivated area of the microwatershed.  Available boron is low (<0.5 ppm) in 1 per cent and medium (0.5-1.0 ppm) in 37 per cent area of the microwatershed.  Available iron is sufficient (>4.5 ppm) in 2 per cent and deficient in 36 per cent area of the microwatershed.  Available manganese and copper are sufficient in the entire cultivated area of the microwatershed.  Available zinc is deficient (<0.6 ppm) in the entire cultivated area of the microwatershed.  The land suitability for 29 major crops grown in the microwatershed were assessed and the areas that are highly suitable (S1) and moderately suitable (S2) are given below. It is however to be noted that a given soil may be suitable for various crops but what specific crop to be grown may be decided by the farmer looking to his capacity to invest on various inputs, marketing infrastructure, market price and finally the demand and supply position. Land suitability for various crops in the Microwatershed Crop Suitability Area in ha (%) Crop Suitability Area in ha (%) Highly suitable (S1) Moderately suitable (S2) Highly suitable (S1) Moderately suitable (S2) Sorghum - - Guava - - Maize - - Sapota - - Bajra - - Pomegranate - - Groundnut - - Musambi - - Sunflower - - Lime - - Redgram - - Amla - - Bengal gram - - Cashew - - Cotton - - Jackfruit - - Chilli - - Jamun - - Tomato - - Custard apple - - Brinjal - - Tamarind - - Onion - - Mulberry - - Bhendi - - Marigold - - Drumstick - - Chrysanthemum - - Mango - -  Apart from the individual crop suitability, a proposed crop plan has been prepared for the identified LMUs by considering only the highly and moderately suitable lands for different crops and cropping systems with food, fodder, fibre and horticulture crops.  Maintaining soil-health is vital for crop production and conserve soil and land resource base for maintaining ecological balance and to mitigate climate change. For this, several ameliorative measures have been suggested to these problematic soils like saline/alkali, highly eroded, sandy soils etc.,  Soil and water conservation treatment plan has been prepared that would help in identifying the sites to be treated and also the type of structures required.  As part of the greening programme, several tree species have been suggested to be planted in marginal and sub marginal lands, field bunds and also in the hillocks, mounds and ridges. This would help in not only supplementing the farm income but also provide fodder and fuel and generate lot of biomass which would help in maintaining an ecological balance and also contribute to mitigating the climate change.