THE FATE OF solUBLE PHOSPHATE APPLIED TO SOILS

Summary It is commonly known that the soluble phosphate added to soils is largely changed into iron and aluminium phosphates in acid soils, and into calcium phosphate in calcareous soils. Recently Chang and Jackson (1957a) employed a method to fractionate the inorganic soil phosphorus into four principal forms, namely, aluminium phosphate, iron phosphate, calcium phosphate, and occluded phosphate, enabling more detailed examination of the fate of applied phosphate to be made using the method of Chang and Jackson (1958). The purpose of this investigation is to study the fixation and transformation of soluble phosphate added to soils of different characteristics under different conditions.