Determination of soil fertility management zones in Veeranam Command for rice production using geostatistical methods, principal component analysis and fuzzy clustering

Crop productivity can be enhanced while reducing environmental threats from excessive fertilization by fully comprehending the spatial variability of soil properties and delineating management zones (MZs). A field investigation was carried out in Veeranam Command area in Southern India to study the spatial variability of soil properties and the delineation of MZs. Grid wise 240 soil samples collected from the study area were analyzed for pH, available macronutrients and micronutrients. The coefficient of variation of the soils varied from low (6.34 %) to high (87.56 %). Geostatistical analysis showed differed spatial variability patterns for the studied soil properties with spatial dependence ranged from moderate to strong and the ordinary kriging method is used to map the distribution of soil properties. MZs were delineated by performing principal component analysis (PCA) and fuzzy K-means clustering. Four PCs with eigen values more than 1 dominated 52.65 % of the total variance, so they were retained for clustering analysis. Six MZs were delineated based on the two criteria modified partition entropy (MPE) and fuzzy performance index (FPI). The studied soil properties differed significantly among MZs. Thus, the methodology used for MZ delineation could be used effectively for soil site-specific nutrient management for avoiding soil degradation concurrently with maximizing crop production in the study area.