Land Evaluation for Site Specific Pigeon Pea (Cajanus cajan) - Sorghum (Sorghum bicolor) Management - A Case Study of Mormanchi Microwatershed, Gulbarga District, Karnataka, India

Aim: Integration of land resource inventory with land suitability to derive optimal land use at farm level.

Study Design: Land resource inventory for farm level planning using transect approach for soil profile studies and then classified soils as per USDA soil taxonomy. The soil series information was used to derive soil map and used GIS to derive crop suitability maps.

Place and Duration of Study: Mormanchi microwatershed in Gulburga tehsil.

Methodology: Detailed soil survey at 1:10000 scale using remote sensing data sets and cadastral maps with transect method of soil profile studies. Identification of soil series and defining soil phases as mapping units to derive soil map for land evaluation for sorghum and pigeon pea using GIS.

Results: The land resource information obtained from detailed soil survey shows that this micro watershed has six soil series belongs to the subgroups of vertisols and vertic integrades having low available sulphur and boron with wide spread phosphorus and Zn deficiency. The soil map with fifteen mapping units was used in land evaluation for sorghum and pigeon pea. The results showed that 35% of total area is evaluated as suitable with limitations of soil depth, gravelliness and slope. To enhance productivity, it is suggested to go for early sowing of pigeon pea with supplementary irrigation in times of dry spells but for sorghum, soil-water conservation measures must be integrated with nutrient management.

Conclusion: The fifteen shrink-swell soil mapping units in Mormanchi Microwatershed were evaluated for sorghum and pigeon pea in northern dry zone having short length of growing period. The results showed that 35% of area is suitable as against the current land use of 85% of total cultivated area.