Ley forming modifier soil structure, which, in turn, effects soil physical characteristics in the upper layer. The objective of this study was to evaluate soil physical attributes and grain yield in a typical dystrophic Red Latosol (Typic Haplorthox) located in Passo Fundo county (RS), Brazil, after eight years of mixed production cultivation (1993 to 2000). The effects of production systems integrating grain production with winter annual and perennial pastures under no-tillage were assessed. Four mixed production systems were evaluated: system I (wheat/soybean, white oat/soybean, and common vetch/corn); system II (wheat/soybean, white oat/soybean, and grazed black oat + grazed common vetch/corn); system III [perennial cool season pastures (fescue + white clover + red clover + birdsfoot trefoil)]; and system IV [perennial warm season pastures (bahiagrass + black oat + rye grass + white clover + red clover + birdsfoot trefoil)]. System V (alfalfa as hay crop) was established in an adjacent area in 1994. The areas under systems III, IV, and V returned to system I after the 1996 summer. The treatments were arranged in a randomized complete block design, with four replicates. As a control, physical soil parameter were evaluated in samples of a subtropical forest fragment adjacent to the experiment. Soil bulk density values were lower in the top layer (0-5 cm) than in the deeper layer (10-15 cm), while the reverse was observed for the total porosity and macroporosity. Systems I, II, III, and IV showed higher bulk density values and lower total porosity and macroporosity values in the surface layer (0-5 cm). System V and subtropical forest presented low bulk density and high total porosity and macroporosity values compared to the other treatments. It was observed no differences between physical attributes of integrated and non-integrated crop and livestock systems. No significant correlation was verified between crop yields and physical soil attributes, with exception of the soil macroporosity under soybean in the 0-5 cm layer.
crop rotation; soil bulk density; total porosity
