Spatial Variability of Soil Physicochemical Properties in the Mid-Central Table Land Zone of Odisha: A Geostatistical Approach

Abstract

Soil is a dynamic body exhibiting spatial variability both at micro- and macro-levels. Spatial distribution maps of various physicochemical soil properties, generated using geostatistical tools, are considered more effective for soil management than traditional methods. The objectives of the present study were to assess the spatial variability of different physiochemical properties of soil viz., sand (%), silt (%), clay (%), water holding capacity (WHC) (%), bulk density (BD) (Mg m-3), pH, and electrical conductivity (EC) (dS m-1) of Tangi-Choudwar block situated in the Mid-Central Table Land of Odisha, India and prepare spatial variability map for the region. Total of 193 soil samples were collected from sampling grids spaced 200 meters apart, from a depth of 0 to 15 cm using a GPS device to record the coordinates. Statistical and geostatistical analyses were performed to characterize the spatial distribution of soil physicochemical properties using various kriging models. The results revealed considerable variability among the properties, particularly for sand, silt, clay, and water holding capacity (WHC), with coefficients of variation (CV) of 143, 47.53, 75.82, and 61.04%, respectively. In Semivariogram analysis properties namely, sand, WHC, pH, and EC fitted well with the Gaussian model Instead, the variability of silt, clay and BD were well explained by exponential and spherical models. Apart from water holding capacity (WHC), all properties exhibited moderate spatial dependence, with nugget-to-sill ratios ranging from 29 to 70%. The regionspecific soil maps will be beneficial to both farmers and policymakers, as they will facilitate the adoption of precision agriculture through site-specific nutrient management and ensure the efficient allocation and application of inputs.