Spatial Modeling of Some Selected Soil Nutrients Using Geostatistical Approach for Jhandutta Block (Bilaspur District), Himachal Pradesh, India

Abstract

In India, the concept of site-specific nutrient management is very important to increase the productivity particularly under rainfed farming systems. In the Himalayan region, the nutrient management is generally limited to small farms, so there is a need to provide better input to the marginal farmers to avoid the threat from land degradation and emerging nutrient deficiencies. The spatial representation of soil variables is one of the viable options to improve soil fertility by soil-specific nutrient management. Thus, the present study was conducted in the Jhandutta block (Bilaspur district), Himachal Pradesh, India, to assess the spatial variability of some selected soil nutrients. A total of 402 soil samples were collected and analyzed. The log transformation was applied to achieve the normality followed by variogram analysis with a geostatistical approach to develop spatial distribution map using ordinary kriging. Semivariogram was calculated to obtain modeling parameters (nugget, sill and range) that helped to identify the minimum sampling distance for better spatial autocorrelation. In the study area, the exponential model was found to be the best-fitted model. Moreover, the geostatistical approach and the spatial distribution maps in GIS platform inferred the current status of soil nutrients with moderate spatial dependence for most of the soil characteristics. Principal component analysis was carried out to aggregate soil variables in groups and finally five PCs with eigenvalues > 1 accounting for 64.4 per cent of the total variance in the dataset. The spatial distribution of the soil nutrients is strongly influenced by environmental and natural factors. The spatial distribution map delineated those areas which need site-specific nutrient management for sustainable agriculture.