Evaluation of Soil Phosphorus Tests and its Relation to Inorganic Phosphorus Forms in Flooded Soils

Field experiments were conducted with rice under flooded condition to evaluate the efficacy of various soil tests for available P. Available P status as estimated by different extractants and its relationship with different inorganic P forms as influenced by various organic manures and P fertilizers under wetland ecosystem is reported. Among different indices of P availability, Olsen’s soil test was found to be the most suitable method. The P extracting power of different extractants was in the order: Mehlich I > Bray I > Truog >Olsen >Morgan.Olsen and Bray No.1 extractants were consistent in extracting P from specific P fractions than the other three extractants. Iron-P was the dominant inorganic P fraction followed by Ca-P,Al-P and saloid-P. Available P in this rice soil depends on the concentration of Fe-P and saloid-P .