A field experiment was conducted to study “Phosphorus use efficiency through PROM (phosphorus rich organic manure) for soybean in highly calcareous soil” at Research Farm, College of Agriculture, Pune during kharif 2023. This experiment consisted of two organic sources (PROM and vermicompost) and two inorganic sources of phosphorus (SSP and DAP) along with their levels @ 50, 75 and 100 % imposed for soybean in calcareous soil. The treatments comprised T1 - Absolute control, T2 - RDF (50:75:45 kg ha-1 N: P2O5: K2O), T3 - 50% P2O5 through PROM, T4 - 75% P2O5 through PROM, T5 - 100% P2O5 through PROM, T6 - 100% P2O5 through DAP + FYM @12.5 t ha-1, T7 - 100% P2O5 through SSP + FYM @12.5 t ha-1 and T8 - 100% P2O5 through vermicompost replicated thrice in randomized block design imposed to soybean in calcareous soil. Significantly superior results were observed for higher nitrogen (82.22 and 24.49 kg ha-1), phosphorus (23.43 and 42.55 kg ha-1) and potassium (49.44 and 81.93 kg ha-1) uptake by grain and straw of soybean with the incorporation of 100 % P2O5 through PROM in calcareous soil. Similar treatment reported 145.41 % increase in Fe, 86.22 % in Mn, 71.92 % Zn and 52.08 % in Cu uptake by soybean. Based on this experiment it could be concluded that incorporation of 100 % P2O5 through phosphorus rich organic manure reported higher nutrient use efficiency (NUE) for nitrogen (129.34 %), phosphorus (38.00 %) and potassium (139.02 %) in calcareous soil under soybean cultivation. It is inferred that incorporation of PROM or vermicompost for the substitution of either 75 or 100 % P2O5 reported significantly higher nutrient uptake and nutrient use efficiency in calcareous soil than that of inorganic fertilizers (SSP and DAP) application or recommended dose of fertilizer or absolute control.
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