Qualidade física de um Latossolo Vermelho distroférrico sob diferentes usos

Abstract

Due to the aspects involved in the water retention by soil regarding different managements, this study was carried out to assess the water retention in the soil and the S index in the diagnosis of the soil structural quality under different management systems. The work was conducted in July/ August, 2013 in the facilities of the Federal University of Lavras. Undisturbed samples were collected from 0 to 20 cm depth layer of an Oxisol under the following uses: conventional tillage of corn, coffee crop, eucalyptus crop and an equilibrium reference (native vegetation). Undisturbed samples were submitted to matrix potentials of -2; -4; -6 and -10 kPa in suction unit, with porous plate funnel, and to Richards’ medium pressure chamber to -33 and -100 kPa and high pressure to -500 and -1500 kPa. The soil structure was assessed based on the attributes: soil density, total porosity, macroporosity and microporosity, determined by the volumetric ring method. In order to calculate the S index, it was used the equation presented by Dexter which is used when the adjustment is done by van Genuchten’s method. The results showed that soil under native vegetation has greater drainage capacity compared to other soil managements. In all assessed conditions, the values of S index were above 0.050, which indicates an adequate soil physical quality under the different management systems adopted.