Asian Soil Research Journal

Understanding soil texture is vital for sustainable agriculture, as it directly affects water retention, nutrient dynamics, and root development. This study aims to assess and map the spatial variability of agricultural soil texture in the Lower Karha River Basin using granulometric analysis and GIS techniques. A total of 48 soil samples were collected using a 10×10 fishnet grid overlay and analyzed using mechanical sieving method for proportion of granule (0.49%–50.42%), sand (25.24%–64.40%), and silt-clay (21.91%–49.94%) fractions. The soils are predominantly sand-rich, with localized zones of finer textures in the southern and lower basin areas. Grain-size statistical parameters were computed to evaluate sedimentological behavior. Mean grain size ranged from –0.73 to 2.20 ϕ, indicating a spectrum from coarse to fine textures. Sorting indices varied between 1.45 ϕ and 2.75 ϕ, classifying most soils as moderately to poorly sorted. Skewness (–0.23 ϕ to 0.83 ϕ) and kurtosis (0.55 ϕ to 1.76 ϕ) values showed diverse asymmetry and peakedness, reflecting heterogeneous depositional environments across the basin. Spatial distribution maps were generated using Inverse Distance Weighting (IDW) in a GIS environment, enabling high-resolution visualization of texture classes and statistical patterns. The results offer critical insights for precision agriculture, informing crop suitability, irrigation scheduling, and localized land-use planning. The study underscores the significance of integrating geostatistical tools with soil texture analysis for effective soil resource management in semi-arid river basins.