LAND RESOURCE INVENTORY AND SOCIO-ECONOMIC STATUS OF FARM HOUSEHOLDS FOR WATERSHED PLANNING AND DEVELOPMENT DHARJAMGA-3 (4D5B7G1b) MICROWATERSHED Gulbarga Taluk, Gulbarga District, Karnataka

Abstract

The land resource inventory of Dharjamga-3 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 and use potentials of the soils in the microwartershed. The present study covers an area of 559 ha in Dharjamga-3 microwatershed in Gulbarga taluk of Gulbarga district, Karnataka. The climate is semiarid and categorized as drought-prone with an average annual rainfall of 740 mm, of which about 540 mm is received during south–west monsoon, 126 mm during north-east and the remaining 74 mm during the rest of the year. An area of about 98 per cent is covered by soils, two per cent by waterbodies, settlements and others. The salient findings from the land resource inventory are summarized briefly below.  The soils belong to 10 soil series and 25 soil phases (management units) and 8 land use classes.  The length of crop growing period is about 120-150 days starting from the 3rd week of May to 1rd 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 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.  About 98 per cent area is suitable for agriculture and 2 per cent is not suitable for agriculture.  About 28 per cent of the soils are moderately deep to deep (75-150 cm), 1 per cent of the soils are very deep (>150cm), 68 per cent are shallow to moderately shallow (25- 75 cm) and about <1 per cent are very shallow (<25 cm) soils.  About 98 per cent of the area has clayey soils at the surface.  About 40 per cent of the area has non-gravelly soils, 59 per cent gravelly to very gravelly soils (15-60 % gravel).  About 17 per cent of the area has soils that are very high (>200mm/m) in available water capacity, 21 per cent medium (100-150 mm/m), and about 60 per cent low (51- 100 mm/m) to very low (<50 mm/m).  About 72 per cent of the area has very gently sloping (1-3%) lands, about 25 per cent area is gently (3-5%) sloping and about 1 per cent area has nearly level (0-1%) lands.  An area of about 26 per cent has soils that are slightly eroded (e1), 50 per cent moderately eroded (e2) and 22 per cent severely eroded (e3).  An area of about 47 per cent has soils that are moderately acid to slightly acid (pH 5.5 to 6.5), about 12 per cent slightly alkaline (pH 7.3-7.8) and 39 per cent area is neutral (pH 6.5-7.3) in soil reaction.  The Electrical Conductivity (EC) of the soils are dominantly <2 dsm-1indicating that the soils are non-saline.  About 8 per cent medium (0.5-0.75%) and 90 per cent high (>0.75%) in organic carbon content.  Major area of 96 per cent has soils that are low (<23 kg/ha) and 2 per cent high (>57 kg/ha) in available phosphorus.  About 54 per cent medium (145-337 kg/ha), 10 per cent high (>337 kg/ha) and 33 per cent low (<145 kg/ha) in available potassium.  Available sulphur is low (<10 ppm) in about 25 per cent area, medium (10-20 ppm) in 72 per cent and 2 per cent high (>20 ppm).  Available boron is low (<0.5 ppm) in about 26 per cent area, 53 per cent medium (0.5-1.0 ppm) and 19 per cent high (>1.0 ppm).  Available iron, manganese and copper are sufficient in all the soils.  About 12 per cent area has soils that are deficient (<0.6 ppm) in available zinc and 86 per cent sufficient (>0.6 ppm).  The land suitability for 19 major crops grown in the microwatershed was 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 157 (28) 78 (14) Guava - 244(44) Maize - 11 (2) Jackfruit - 2(<1) Red gram - 210 (38) Jamun - 189(38) Sunflower 157 (28) - Musambi 96 (17) 148(26) Cotton 96 (17) 139 (25) Lime 96 (17) 148(26) Sugarcane - - Cashew 2 (1) 7(1) Soybean 157(28) 54 (10) Custard apple 237 (42) 223(40) Bengalgram 198(35) 118(21) Amla 237 (42) 84 (15) Mango - 2(<1) Tamarind - 190 (34) Sapota - 243(43) Apart from the individual crop suitability, a proposed crop plan has been prepared for the 8 identified LUCs by considering only the highly and moderately suitable lands for different crops and cropping systems with food, 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. This would helps in not only supplementing the income but also provide fodder and fuel, generate lot of biomass thus helping in maintaining an ecological balance also helps in mitigating the climate change.