A comparative study of phosphorus availability in an acidic soil and an alkaline soil amended with organic and inorganic phosphorus sources

An incubation study was conducted to investigate the effects of adding cow manure (CM), poultry manure (PM), city waste (CW) and triple super phosphate (TSP) on extractable P in a sandy loam acidic soil (Aquepts) and a silt loam alkaline soil (Fluvents). Phosphorus was added at a rate of 200 mg P kg -1 to the soil in the forms of CM, PM, CW and TSP. The soil was incubated at field capacity for 15, 30 and 60 days after which the P sources were extracted with Olsen, Kelowna, Mehlich-3, and Bray and Kurtz-II extractants. Regardless of the extractants and soils, after 15 days of incubation, the highest extractable P source was the TSP (88-97 mg kg -1 as Olsen…