Preparation and characterization of phospho-composts: effect of rock phosphate source, P enrichment and Pyrites level

Phospho-composts were prepared with two indigenous phosphate rocks, namely Udaipur and Mussoorie, applied at three levels (0, 2 and 4 kg P 100 kg⁻¹ substrate) and three levels of pyrites (0, 1 and 2 kg S 100 kg⁻¹ substrate) using rice straw as substrate after 120 days of composting. Prepared phospho-composts were analysed for C, N, C:N ratio, total P, inorganic P, organic P, acid as well as alkaline phosphatases and microbial biomass carbon. No significant difference was observed with RP type with respect to total P content. Phosphate enrichment @ 2 per cent was more effective than 4 per cent P enrichment. Pyrites addition was not effective in increasing the total P content but it increased organic P and N content. Addition of 1 per cent pyrites was more effective than 2 per cent.