Spatial variability of the physical attributes of soil under pasture

ABSTRACT The aim of this work was to evaluate the spatial variability of the physical attributes of the soil in areas of a Latosol, Argisol and Cambisol under pasture. Knowledge of such variability is important, as it influences the quality of the pasture and groundwater recharge. For each study area, 154 georeferenced samples were collected. To analyse the data both descriptive statistics and geostatistics were used. Spatial dependence was seen for most of the physical attributes; saturated hydraulic conductivity and bulk density for the three soil classes; and microporosity, macroporosity and total porosity in the areas of Cambisol and Latosol. The results of the descriptive statistics, and the fact that the pattern of spatial dependence did not remain constant, show that the class of soil, together with the slope and land use, influenced the spatial variability of the physical attributes of the soil being analysed, and that an average value is not enough to represent the spatial distribution of the analysed variables. The sample grid that was used is adequate, making it possible to capture the spatial dependence of most of the variables being analysed.