Assessment of Spatial Variability of Soil Properties Using Geospatial Techniques for Enhanced Productive Capacity of Agricultural Systems in India

Abstract

Soil is an important source of available nutrients. Either shortage or surplus of available nutrients in the soil would limit growth of crops. Understanding the spatial variability and distribution patterns of soil available nutrients is essential for soil management with respect to fertilizer application. A total of 111 geo-referenced soil samples were collected on 300 m x 300 m grid at a depth of 0–15 cm, processed and analyzed for pH, EC, soil organic carbon (SOC), available nitrogen (AN), available phosphorus (AP), available potassium (AK), available sulphur (AS), available iron (Fe), available manganese (Mn), available zinc (Zn)  and available copper (Cu). Soil properties coefficients of variation (CVs) of soil properties widely varied from low (5.22%) to moderate (49.28%). The geostatistics and geographic information system (GIS) techniques were applied. Ordinary kriging and semivariogram analysis showed differed spatial variability patterns for the studied soil properties with spatial dependence ranged from moderate to strong. The semivariograms for the soil properties were best fitted with spherical model. The range of influence for available N, P, K and S were 268, 287, 497 and 706 m, respectively.  The spatial ranges of available Fe, Mn, Zn and Cu were 1050, 1150, 1470, and 1430 m, respectively. The spatial dependence class was strong for EC, SOC, available P, K and was moderate for available N, S, Fe, Mn, Zn and Cu. The available N and P is categorized as low (<280 kg ha-1) and low (<11 kg ha-1) to medium (<22 kg ha-1), respectively were the main limiting factors in crop production.  The availability K was categorized as medium (118-280 kg ha-1) to high (> 280 kg ha -1).  The soil nutrient maps generated would help to provide precise fertilizer recommendations for sustainable production and environmental conservation.