LAND RESOURCE INVENTORY AND SOCIO-ECONOMIC STATUS OF FARM HOUSEHOLDS FOR WATERSHED PLANNING AND DEVELOPMENT HALHALLI (4D3A9D1b) MICROWATERSHED Koppal Taluk and District, Karnataka

Abstract

The land resource inventory of Halhalli 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 these 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 734 ha in Koppal taluk and district, Karnataka. The climate is semiarid and categorized as drought - prone with an average annual rainfall of 662 mm, of which about 424 mm is received during south –west monsoon, 161 mm during north-east and the remaining 77 mm during the rest of the year. An area of about 95 per cent is covered by soils, three per cent by rock-out crops and two per cent by water bodies, settlements and others. The salient findings from the land resource inventory are summarized briefly below.  The soils belong to 15 soil series and 31 soil phases (management units) and 8 land use classes.  The length of crop growing period is <90 days and starts from 2nd week of August to 2nd week of November.  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 28 major agricultural and horticultural crops were assessed and maps showing the degree of suitability along with constraints were generated.  Entire area is suitable for agriculture.  About 1 per cent of the soils are shallow (25-50 cm), 22 per cent is moderately shallow (50-75 cm), 31 per cent moderately deep (75- 100 cm) and 40 per cent has deep to very deep soils (100 ->150 cm).  About 5 per cent of the area is having sandy soils, 54 per cent loamy soils and 36 per cent has clayey soils at the surface.  About 46 per cent of the area has non-gravelly (<15%) soils, 45 per cent has gravelly soils (15-35 % gravel) and 4 per cent has very gravelly (35- 60% gravel) soils.  With respect to available water capacity 44 per cent of the area has very low (<50mm/m), 30 per cent of the area has low (51-100 mm/m), 11 per cent medium (101-150 mm/m) and 11 per cent area has high to very high (151 - >200mm/m) .  An area of about 6 per cent has nearly level (0-1%) lands and 89 per cent has very gently sloping (1-3%) lands.  An area of about 45 per cent is slightly eroded (e1) and 50 per cent is moderately eroded (e2) lands.  An area of about 2 per cent is very strongly acid to strongly acid (pH 4.5-5.5), 27 per cent is moderately acid to slightly acid (pH 5.5 -6.5), 25 per cent is neutral (pH 7.3-7.8), 36 per cent is slightly to moderately alkaline (pH 7.3-8.4), 4 per cent is under strongly alkaline to very strongly alkaline (pH 8.4- >9.0) in reaction.  The Electrical Conductivity (EC) of the soils are dominantly <2 dsm-1 indicating that soils are non saline.  Organic carbon is low (<0.5%) in about 11 per cent, medium (0.5-0.75%) in 43 per cent and high (>0.75 %) in 41 per cent area of the soils.  Available phosphorus is low (<23 kg/ha) in < 1 per cent, medium (23-57 kg/ha) in 61 per cent and high (>57 kg/ha) in 34 per cent of the soils.  Available potassium is low (<145 kg/ha) in 3 per cent, medium (145-337 kg/ha) in 75 per cent and high (>337 kg/ha) in 17 per cent of the soils.  Available sulphur is low (<10 ppm) in 25 per cent, medium (10-20 ppm) in 37 per cent and high (>20 ppm) in 33 per cent area of the soils  Available boron is low (<0.5 ppm) in about 62 per cent and medium (0.5-1.0 ppm) in 33 per cent area of the soils.  Available iron is deficient in 49 per cent of the area and sufficient (>4.5 ppm) in 46 per cent of the area.  Available zinc is deficient (<0.6 ppm) in 81 per cent of the area and sufficient (>0.6 ppm) in 14 per cent of the area.  Available manganese and copper are sufficient in the entire area.  The land suitability for 28 major agricultural and horticultural crops grown in the microwatershed was assessed and the areas that are highly suitable (class S1) and moderately suitable (class 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 84(12) 81 (11) Pomegranate 42(6) 201(28) Maize 5(<1) 150(20) Guava 42(6) 159(22) Bajra 67(9) 330(45) Jackfruit 42(6) 159(22) Redgram 42(6) 106 (15) Jamun 37(5) 167 (23) Bengal gram 42 (6) 268 (37) Musambi 83 (11) 160(22) Groundnut 62(8) 441(60) Lime 83(11) 160 (22) Sunflower 83 (11) 65(9) Cashew 42(6) 188(26) Cotton 79(11) 86(12) Custard apple 110 (15) 543(74) Chilli 42(6) 81(11) Amla 67(9) 585(80) Tomato 42(6) 81(11) Tamarind 37(5) 46 (6) Drumstick 42(6) 283(39) Marigold 42(6) 123 (17) Mulberry 42(6) 446(61) Chrysanthemum 42(6) 123 (17) Mango 37(5) 5(<1) Jasmine 42(6) 81(11) Sapota 42(6) 159(22) Crossandra 42(6) 122(17) Apart from the individual crop suitability, a proposed crop plan has been prepared for the 8 identified LMUs by considering only the highly and moderately suitable lands for different crops and cropping systems with food, fodder, fibre and other 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 for 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 supplementing the farm income, provide fodder and fuel, and generate lot of biomass which in turn would help in maintaining the ecological balance and contribute to mitigating the climate change.