International Journal of Plant & Soil Science

A study was conducted at the Post Graduate Laboratory, Division of Soil Science, College of Agriculture, Pune to study the nutrient release pattern and soil enzyme activities in calcareous and non-calcareous soils as influenced by various levels of phosphorus using organic and inorganic sources. An incubation experiment was laid out in a factorial completely randomized design with seven treatments three replications. The study demonstrated that applying 100% P₂O₅ through Phosphate Rich Organic Manure (PROM) significantly improved soil nutrient status, particularly in non-calcareous soils, with the reduction in soil pH and calcium carbonate, improving organic carbon, and enhancing the availability of macronutrients (nitrogen, phosphorus, potassium). Enzyme activities, viz. urease, dehydrogenase and alkaline phosphatase were higher in non-calcareous soils, correlating positively with nutrient availability, particularly with phosphorus and micronutrients such as iron and manganese. Phosphate Rich Organic Manure (PROM) application was more effective than chemical fertilizers in nutrient mobilization and improving soil enzyme activity over 120 days of incubation. Strong correlations were observed between enzyme activity and micronutrient availability, especially in treatments receiving 100% P₂O₅ through PROM, indicating its potential to enhance both nutrient cycling and soil fertility.