Effect of soil properties on the transformation of phosphorus in acid soils

The effect of soil properties on the transformation of native and added P into different inorganic P fractions in 14 acid soils (Inceptisols, Entisols, Mollisols, Alfisols, Ultisols) and their partial contribution to available P was investigated. After eight weeks of incubation, native Fe-P, Ca-P and available P increased at the expense of saloid-P and Al-P. The pH, cation exchange capacity, clay, organic carbon and active Al and Fe contents, individually had no significant effect on the transformation of added P into saloid-P and Al-P. The clay and extractable Fe contents increased the transformation of added P into Fe-P. The Ca-P increased with pH but decreased with extractable Al and Fe. The available P increased with pH but decreased with organic carbon. The partial contribution of soil properties to saloid-P, Al-P, Fe-P, Ca-P and available Pwas 28.4, 75.1, 75.5, 94.9 and 67.9 per cent, respectively. The available P had non-significant correlation with any inorganic P fraction, while all these P fractions jointly contributed to 44.8 per cent variation in available P.