Disponibilidade de enxofre em solos brasileiros. IV. Avaliação do potencial de fornecimento de enxofre

Abstract

An open incubation experiment was carried out in laboratocy conditons using columns containing 50 g of soil from seven soils of the States of São Paulo, Minas Gerais and Goiás (Brazil), in presence and absence of liming. Soil columns were leached with KCI O.OI M evecy other week during 14 weeks. A second greenhouse experiment was carried out with twelve soils from the sarne States. Com (Zea mays L.) was grown in two successive croppings in presence ofthree rates of S (O, 20 and 40 ppm) applied as gypsum. Total sulphur and carbon contents and sulphur mineralization potentials of the soils were correlated with sulphur absorption by com plants. Total sulphur contents of soils showed no significant correlation with sulphur uptake (r=0.234 n.s.). Camon content was significantly correlated with sulphur uptake in presence of liming (r=0.754 .. , n=36), being lower in its absence (r=0.457', n=36). Sulphur minerafü.ation potentials of soils were significantly correlated with sulphur uptake by com in presence of liming (r=0.797 .. , n=21), with no significance in its absence (r=0.373 n.s.). Injoint analysis (no liming and liming) there was also a highly significant correlation (r=O. 753'', n=42). Toe best correlations of carbon contents and sulphur rninerali7.at:ion potentials of the soils with sulphur uptake in presence of liming can be accounted for by organic sulphur mineralization and inorganic S-SO/ desorption.