Journal of Global Agriculture and Ecology

A study was conducted at Post Graduate Laboratory, Division of Soil Science, College of Agriculture, Pune to study the nutrient release pattern and soil enzyme activities of calcareous soil as influenced by various levels of phosphorus using organic and inorganic sources. The experiment was conducted in randomized block design with seven treatments replicated three times. The treatments comprised as T₁- Absolute control, T₂ - RDF (50:75:45 N: P₂O₅:K₂O kg ha^-1) through DAP, T₃ - RDF (50:75:45 N: P₂O₅: K₂O kg ha^-1) through SSP, T₄- 25 % P₂O₅ through PROM, T₅- 50% P₂O₅ through PROM, T₆ -75% P₂O₅ through PROM and T₇ -100% P₂O₅ through PROM and RDF of soybean was used for incubation. The study demonstrated that applying 100% P₂O₅through Phosphate Rich Organic Manure (PROM) significantly improved soil poperties, by reducing soil pH and calcium carbonate, increasing organic carbon, and enhancing the availability of macronutrients (nitrogen, phosphorus, potassium) and micronutrients (iron, manganese, zinc, copper). Enzyme activities, including urease, dehydrogenase and alkaline phosphatase were improved in calcareous soils, correlating positively with nutrient availability, particularly with phosphorus and micronutrients such as iron and manganese. PROM application was more effective than chemical fertilizers in promoting nutrient mobilization and improving soil enzyme activity over a 120-day incubation period. Strong correlations were observed between enzyme activity and micronutrient availability, especially in treatments receiving 100% P₂O₅through PROM, indicating its potential to enhance both nutrient cycling and soil fertility.