Soil nutrient status mapping of Nagenahalli micro-watershed under Eastern Dry Zone of Karnataka by remote sensing, detailed soil survey and GIS techniques

Soil nutrients are essential for crop growth. Spatial variability of nutrients can occur in various scales, between regions, between fields or within the field. RS and GIS techniques enables farm management based on small-scale spatial variability of soil and crop parameters in the field. The present study was carried out in Nagenahalli microwatershed, Doddaballapur taluk, Bangalore rural district with the objective to determine and map the macronutrient status of soils in the watershed using GIS technique. The NPK was analyzed and mapped using Arc GIS to quantify the level of spatial nutrients availability. Results indicated that NPK ranged from 31.36 to 376.32 kg ha-¹(N), 21.29 to 390.62 kg ha⁻¹ (P₂O₅) and 55.10 to 521.47 kg ha⁻¹ (K2O) respectively in the surface soils. Nutrient map showed that the soils were poor in available nitrogen and available potassium whereas sufficient in available phosphorous content. Furthermore NPK map can be used to identify deficient or sufficient areas for efficient fertilizer management.