Soil quality mapping in the groundnut belt of erstwhile Mahabubnagar District, Telangana, India using GIS

The present study was conducted during rabi season of 2019–20 based on the crop colonies concept, where the highly and marginally potential regions for groundnut were delineated with an objective of soil fertility assessment in the crop area in order to determine the yield gaps and constraints for low yields in marginally potential areas. Soil samples collected at 35 GCP sites through preliminary crop survey in homogenous, contiguous groundnut areas at the time of crop-cut experiments were analysed in the laboratory for soil quality parameters. The results revealed that the soils were slightly saline (pH: 7.50–8.50) with low saline EC (<0.25 dS m^–1), high organic carbon content (>0.75%), acutely deficit available nitrogen (<100 kg ha^–1), high phosphorus (>24.6 kg ha^–1), medium potassium (108–280 kg ha^–1) and low sulphur (<10 mg kg^–1). The DTPA extractable micronutrients – zinc, manganese and copper were sufficiently high (Cu > 0.20 mg kg^–1; Zn > 0.65 mg kg^–1 and Mn > 2 mg kg^–1), while iron was low (<4 mg kg^–1). Based on the results of laboratory analysis soil quality maps were generated using QGIS software, wherein each parameter was grouped into several classes based on USDA soil classification employing IDW interpolation technique.