Comportamento do P-ocluso em um solo sob vegetação de cerrado e dificuldades analíticas na sua determinação.

Abstract

In this work was studied the P-occlude behaviour in “cerrado” soil which was previous treated with five phosphate fertilization levels. The proceedings adopted was a strong attack through the use of concentraded HCl, HNO3 and H2SO4 on the reminder soil samples on P-Inorganic (P-NH4Cl, P-Al, P-Fe e P-Ca) extractions. The phosphorus was spectrophotometrically quantified with sulfur-bismuth-molibdic reagent using of ascorbic acid as reductor. The samples were collected on four periods spaceds four months one another. The results pointed out high values of P-occlude on the highest phosphatic fertilization levels and certain stability from 2th to 4th sample periods.