Geostatistical Assessment of Soil Fertility and Spatial Variability in Kota District, Rajasthan, India

Abstract

Soil fertility in semi-arid regions often limits crop productivity due to uneven nutrient distribution. To explore this in Kota district, Rajasthan, India, 200 surface soil samples (0–15 cm) were collected from five blocks and analyzed for pH, electrical conductivity (EC), organic carbon (OC), major nutrients (N, P, K, S), and micronutrients (Zn, Fe, Mn, Cu). Soils were generally neutral to moderately alkaline (pH 6.2–8.9) and non-saline (EC <1 dS m⁻¹). Organic carbon and nitrogen were mostly low to medium; phosphorus was low to medium, and potassium ranged from medium to high. Sulphur deficiency occurred in about one-third of the samples, particularly in Itawa and Sangod, while zinc deficiency affected 45% of soils. Other micronutrients (Fe, Mn, Cu) were adequate. GIS-based maps revealed clear block-level differences, highlighting both fertile zones and nutrient-deficient areas. These findings emphasize the need for site-specific nutrient management strategies, including organic carbon enhancement and balanced N, P, S, and Zn application, to sustainably improve crop productivity. This study provides a practical baseline for farmers, extension workers, and planners to make informed land management decisions in Kota district.