Mineralization of phosphorus as influenced by different organic and inorganic sources of phosphorus in calcareous soil

Abstract

A laboratory incubation experiment was carried out at Division of Soil Science and Agricultural Chemistry, RCSM College of agriculture, Kolhapur under MPKV, Rahuri, during 2021-22 The study for 90 days was initiated to evaluate the effect of different organic manure alone and in combination with inorganic fertilizer of phosphorus on release pattern of phosphorus in calcareous soils at field capacity of soil moisture. The experiment was laid out in a Factorial Completely Randomized Design (FCRD) with three replication and fifteen treatments. The treatment comprised of Control, FYM, VC, POL, PMC, SSP, DAP, SSP+ FYM, SSP +VC, SSP + POL, SSP + PMC, DAP+ FYM, DAP+VC, DAP+ POL, DAP+ PMC. The results revealed that the phosphorus release rate was slow in the beginning, followed by a sharp increase, reaching a peak rate at 45 days of incubation, followed by a gradual decline thereafter in all the organic sources however press mud compost and poultry manure were found to be continuous source of phosphorus during the incubation period. Application of diammonium phosphate as inorganic source of phosphorus was more prominent as compared to SSP in calcareous soils. Diammonium phosphate could be better option in calcareous soil to elevate phosphorus requirement as compared to SSP. The combination of inorganic and organic sources was found to be more pronounced as compared to only organic or inorganic treatment in supplementing phosphorus in calcareous soil. Use of DAP along with organic sources should be advocated over SSP in combination with organic sources. Application of DAP along with press mud compost or poultry manure could be more reliable combination to ensure maximum availability of phosphorus in calcareous soil.