Application of Geographical Information System to Understand Spatial Variability of Soil Available Nutrients in Northern Karnataka, India

Abstract

It is very important to distinguish the spatial variability in soil fertility for site specific nutrient application. To know the status, 25 soil samples were collected from Vandurga Village, Yadgir District, Karnataka, India. Samples were analysed for electrical conductivity (EC), power of hydrogen (pH), organic carbon (OC), Nitrogen (N), Phosphorous (P2O5) and Potassium (K2O). Further, SPSS (ver. 19) was used to execute conventional statistical analysis and ArcGIS to get the information about distribution and spatial variability of soil available nutrients. The analysis results showed that the EC of soil varied from 0.13 to 0.25 dS/m with a mean of 0.18 dS/m. The PH ranged from 6.62 to 8.82 with an average of 7.89. Available OC ranged from 0.14 % to 1.90 % with mean of 0.78 %. Similarly mean values for N, P2O5 and K2O observed 215.3 kg/ha, 31.5 kg/ha, and 513.4 kg/ha, respectively. The SD and CV for EC was 0.031 and 16.69%, respectively, while for pH, OC, N, P2O5 and K2O it was found to be 0.56 and 7.04, 0.39 and 51.16, 100.9 and 46.86, 19.12 and 60.61, 160.88 and 31.33 respectively. Spatial variability maps for various nutrients prepared shows the huge variation in the soil nutrients availability. This variability appeared due to lack of balanced application of fertilizers. It was suggested that an appropriate applications of nutrients necessary for selected land based on soil nutrients.