Effect of organic amendments on availability of different chemical fractions of phosphorus

A laboratory experiment was conducted under laboratory conditions to investigate the effect of organic amendments applied through FYM @ 20 t ha⁻¹, vermicompost @ 20 t ha⁻¹, poultry manure @ 20 t ha⁻¹ and paddy straw @ 20 t ha⁻¹ respectively, on chemical fractions and availability of phosphorus. Soil treated with organic amendments incubated at room temperature and study of chemical fractions and availability of phosphorus at 2, 4, 7, 14, 21, 28, 40 and 60 days of incubation. All organic amendments application increased the Olsen's P in comparison to no application of organic amendments respectively. Availability of phosphorus increased in the order of paddy straws @ 20 t ha⁻¹ < FYM @ 20 t ha⁻¹ < vermicompost @ 20 t ha ¹ < poultry manure @ 20 t ha⁻¹ respectively. FYM @ 20 t ha⁻¹ show significantly increased of saloid-P, Al-P and Fe-P but showed non-significantly increase in Ca-P. Poultry manure @ 20 t ha⁻¹ significantly increased of all fractions of phosphorus. In general, the range of saloid-P, Al-P, Fe-P and Ca-P was observed 4.22–22.40, 8.45–32.43, 12.67–35.38 and 164.85–215.29 mg kg⁻¹ respectively, while total P and available P in soil ranged from 351.38–423.21 mg kg⁻¹ and 14.42–25.52 kg ha⁻¹ respectively, in organically amended soil during the incubation period.