Atributos físicos do solo em quatro sistemas de uso da terra em São Carlos, SP

The objective of this work was to evaluate the effect of four land use systems: two agroforestry systems (agrisilviculture and silvopastoral system), single pasture of Urochloa decumbens and native forest, on the physical characteristics of the soil, in Sao Carlos, SP, Brazil. Soil density, macroporosity, microporosity and total porosity, and the stability of aggregates, in the layers of 0-0.05, 0.05-0.20 and 0.20-0.40 m, we were analyzed in the year 2015. The experimental design was a completely randomized design with four replications. The data were submitted to the F test and the means were compared by the Tukey test. The multivariate analysis was applied using the Ward method and the Euclidean distance with standardized variables. It was verified that the soil under native forest presents better physical conditions than the areas with other forms of land use. The physical characteristics of the soil in the agroforestry systems did not vary according to the distance of the trees. The conventional pasture presented soil compaction in the 0-0.40 m layer. Considering the set of variables studied, it was possible to separate three groups, by similarity of the set of physical attributes of the soil: (1) secondary native forest, (2) agrisilviculture and (3) that formed by conventional pasture and silvopastoral system.