Spatial distribution of soil macronutrients and nutrient index for sustainable agriculture in the Khulna region of Bangladesh

Abstract

Abstract Purpose Evaluation of soil fertility is essential for sustainable agriculture; yet studies on nutrient distribution indices, particularly in Bangladesh, remain limited despite increasing research. The purpose of this study is to identify nutrient indices and create spatial distribution maps using ArcGIS in order to evaluate the macronutrient status of the soil in Khulna. Methods In 2021, 22 soil samples, ranging in depth from 0 to 15 cm, were taken during a field survey. To assess soil fertility and nutrient index, those samples were submitted to physicochemical analyses in the lab using standard procedures. These analyses included total nitrogen (N), available phosphorus (P), available sulfur (S), available potassium (K), available calcium (Ca) and magnesium (Mg), and organic matter (OM). Results The findings showed wide variability in nutrient concentrations of N ranged from 0.001% to 0.016%, OM up to 4.19%, and P from 2.17 to 113.39 ppm. Sulfur had a moderate CV (34.28%) and was mostly in the very high category. Results revealed positive relationships between N and Ca, and negative correlations between N and K, and S and Mg. The nutrient index indicated that N and P were generally low to medium, while S, K, Ca, Mg, and OM were mostly high. Conclusions This knowledge plays a crucial role in guiding stakeholders in making informed decisions by understanding the environmental, economic, and agronomic implications of nutrient use; thereby, stakeholders can adopt practices that enhance soil fertility, reduce environmental degradation, ensure food safety, and support the long-term sustainability of agricultural systems.