LAND RESOURCE INVENTORY FOR WATERSHED PLANNING AND DEVELOPMENT YADGIR (4D5B1I2f) MICROWATERSHED Yadgir Taluk and District, Karnataka

Abstract

The land resource inventory of Yadgir 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 468 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 90 (19%) ha in the microwatershed is covered by soils, about 100 ha covered by (21%) rock outcrops, about 14 ha (3%) covered by mining/ industrial area and about 264 ha (56%) by others (Habitation and water body). The salient findings from the land resource inventory are summarized briefly below.  The soils belong to 3 soil series and 3 soil phases (management units) and 3 land management units.  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.  An area of about 19 per cent is suitable for agriculture in the microwatershed.  About 2 per cent area of the microwatershed has soils that are very deep (>150 cm), 13 per cent soils are moderately deep (75-100), whereas 4 per cent soils are moderately shallow (50-75 cm) in the microwatershed.  About 4 percent soils are loamy and 15 per cent is clayey soils at the surface.  Entire cultivated area in the microwatershed has non gravelly (<15%) soils.  About 2 per cent area of the microwatershed is very high (>200 mm/m) in available water capacity and 17 per cent soils are low (51-100 mm/m) and very low (<50mm/m) in available water capacity.  Entire cultivated area is very gently sloping (1-3% slope) lands in the microwatershed.  Entire cultivated area is moderately (e2) eroded in the microwatershed.  Entire cultivated area in the microwatershed is neutral (pH 6.5-7.3), in soil reaction.  The Electrical Conductivity (EC) of the soils in the entire cultivated area of the microwatershed is <2 dsm-1 indicating that the soils are non-saline.  An area of 6 per cent is high (>0.75%), 12 percent is medium (0.50-0.75%) and <1 percent is low (<0.50%) in organic carbon content.  An area of 10 percent is medium (23-57 kg/ha) and 9 percent soils are high (>57 kg/ha) in available phosphorus.  An area of about <1 percent is high (>337kg/ha) and about 19 percent is medium (145-337kg/ha) in available potassium.  An area of about 17 percent is medium (10-20ppm) and 2 percent area is low (<10ppm) in available sulphur.  Available boron is low (<0.5 ppm) in an area of about 16 per cent, medium (0.5-1.0 ppm) in about 2 per cent and high (>1.0 ppm) in about <1 per cent soils.  Available iron content is sufficient (>4.5ppm) in almost entire cultivated area of 19 per cent and deficient (<4.5 ppm) a very minor area of the microwatershed.  Available manganese and copper are sufficient in all the soils of the microwatershed.  Available zinc content is deficient (<0.6 ppm) which covers an area of about 13 per cent and sufficient (>0.6 ppm) in an area of 6 per cent in 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 - 71(15) Guava - 62(13) Maize 62(13) 9(2) Sapota - 62(13) Bajra 62(13) 9(2) Pomegranate - 62(13) Groundnut 62(13) - Musambi - 62(13) Sunflower - 62(13) Lime - 62(13) Redgram - 71(15) Amla 62(13) - Bengal gram - 9(2) Cashew - 62(13) Cotton - - Jackfruit - 62(13) Chilli 62(13) - Jamun - - Tomato 62(13) - Custard apple 62(13) - Brinjal 62(13) - Tamarind - - Onion 62(13) - Mulberry - 62(13) Bhendi 62(13) - Marigold 62(13) Drumstick - 62(13) Chrysanthemum 62(13) 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, fiber and horticulture crops.  Maintaining soil-health is vital to 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 submarginal 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 to generate lot of biomass which would help in maintaining an ecological balance and also contribute to mitigating the climate change.