LAND RESOURCE INVENTORY AND SOCIO-ECONOMIC STATUS OF FARM HOUSEHOLDS FOR WATERSHED PLANNING AND DEVELOPMENT KETHAHALLI (4B3E1G2a) MICROWATERSHED Chamarajanagara Taluk, Chamarajanagara District, Karnataka

Abstract

The land resource inventory of Kethahalli 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 boundries. The soil map shows the geographic distribution and extent, characterstics, classification, behaviour and use potentials of the soils in the microwartershed. The present study covers an area of 626 ha in Kethahalli microwatershed in Chamarajanagara taluk and district, Karnataka. The climate is semiarid and categorized as drought- prone with an average annual rainfall of 769 mm, of which about 316 mm is received during south –west monsoon, 252 mm during north-east and the remaining 201 mm during the rest of the year. 96 per cent area is covered by soils and remaining 4 per cent is by habitation and waterbodies. The salient findings from the land resource inventory are summarized briefly below.  The soils belong to 15 soil series and 43 soil phases (mapping units) and 9 land use classes.  The length of crop growing period is about 150 days starting from the last week of July to 4th 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 250 m grid interval.  Land suitability for growing major agricultural and horticultural crops were assessed and maps showing degree of suitability along with constraints were generated.  Entire area is suitable for agriculture.  Major area of about 24 per cent has deep to very deep (100- >150 cm) soils, an area of 21 per cent has moderately deep (75-100 cm) soils. Maximum area of about 33 per cent is under moderately shallow (50-75 cm) soils and shallow (25- 50 cm) soils occupy 19 per cent area in the microwatershed.  Maximum area of about 64 per cent has loamy soils at the surface loamy sand soils of about 23 per cent and clayey soils 9 per cent at the surface.  Maximum area of about 55 per cent gravelly (15-35%) soils and followed by very gravelly (35-60%) soils of 42 per cent in the microwatershed.  About 84 per cent of the area has very gently sloping (1-3% slope) lands and about 12 per cent area is nearly level (0-1% slope) lands.  An area of about 87 per cent has soils that are slightly eroded (e1) and 9 per cent moderately eroded (e2).  Small area of about 3 per cent soils are slightly to moderately acid (pH 5.5-6.5), 30 per cent area has neutral (pH 6.5-7.3) soils and 63 per cent has slightly to strongly alkaline (pH 7.3-9.0) soils in the microwatershed.  The Electrical Conductivity (EC) of the soils are dominantly <2 dsm-1indicating that the soils are non-saline.  About 57 per cent area is low (<0.5%), 31 per cent area has soils that are medium (0.5-0.75%) and 9 per cent high (>0.75%) in organic carbon.  An area of 43 per cent has soils that are low (<23 kg/ha), 45 per cent medium (23-57 kg/ha) and high (>57 kg/ha) in 9 per cent area in available phosphorus.  An area of about 48 per cent has soils that are medium (145-337 kg/ha) and 49 per cent area has high (>337 kg/ha) in available potassium.  Available sulphur is low (<10 ppm) in about 24 per cent area, medium (10-20 ppm) in 39 per cent area and high (>20 ppm) in about 33 per cent area.  Available boron is low (<0.5 ppm) in about 17 per cent area and medium (0.5-1.0 ppm) in 66 per cent area and high (>0.5%) in 13 per cent area.  About 79 per cent area has soils that are deficient (<4.5 ppm) in available iron and 18 per cent area sufficient (>4.5ppm) in iron.  Available manganese and copper are sufficient in all the soils.  An area of about 79 per cent has soils that are deficient (<0.6 ppm) and 17 per cent soils are sufficient in available zinc.  The land suitability for nine major crops (agricultural and horticultural) 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 Crops Suitability area in ha (%) Highly suitable (S1) Moderately suitable (S2) Sorghum 4 (<1) 442 (71) Maize 4 (<1) 404 (65) Finger millet 4 (<1) 442 (71) Red gram 4 (<1) 442 (71) Groundnut 4 (<1) 442 (71) Cotton 4 (<1) 442 (71) Chilli 4 (<1) 442 (71) Mango - 16 (3) Sapota - 12(40) Apart from the individual crop suitability, a proposed crop plan has been prepared for the 9 identified LUCs by considering only the highly and moderately suitable lands for different crops and cropping systems with food, fodder, fibre and horticulture crops that helps in maintaining the ecological balance in the microwatershed.  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. That would help in supplementing the farm income, provide fodder and fuel, generate lot of biomass, which inturn would help in maintaining the ecological balance and contribute to mitigating the climate change.