Extraction of various forms of phosphorus in soil of the São Paulo state, Brazil, using various chemical methods

Abstract

Various extractions methods for soluble P, organic P and total P, were compared on five soils of the State of São Paulo, Brazil, namely: a. sandy quartz (Entisol), b. red yellow podzolic, Lara variation (Ultisol); c. red-ocre latosol (Oxisol); d. red yellow podzolic, Piracicaba variation (Ultisol); e. terra roxa estruturada (Alfisol). According to the data, the following conclusions were drawn: 1. The best extractants for soluble P were H2SO4 0,05 N (IAC methods) and H2SO4 0,025 N + HC1 0,05 N (Mehlich method) . 2. For removing and measuring the organic P, the extractants were equivalents. 3. The chemical method of Sommers & Nelson and . that of Jackson were the best for the total P in the soil.