Abstract

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 .

Keywords: Labile P, Soil tests, Inorganic P forms, P fertilizers, Organic manures.