| This paper reviews the literature related to total and organic P (Po) levels present in both agricultural and forest soils from southern Chile. Different reports have demonstrated the high contents of total P (Pt) found in agricultural soils (1,000-3,000 mg kg-1) even in unfertilized soils. In most soils Po represents more than 50% of Pt, mainly as inositol penta- and hexaphosphates linked to Fe and/or Al. Lipid-P has been found in very small quantities suggesting very fast cycling. When phosphate fertilizers are applied to these soils, the bulk of P is accumulated as macromolecular-P complexes closely associated with soil organic matter. Close relationships have been found between organic C and Po and between Po and P associated with humic acids (HA-P).... |
