The objective of this study was to determine the effect of cover crop mulches on the physical quality of a distrophic Red Latosol (Oxisol) under no-tillage. The experiment was carried out under center pivot at Embrapa Rice & Beans, in Santo Antônio de Goiás, GO, in a randomized block design, with eight replications. The treatments consisted of eight cover crops: Brachiaria brizantha; corn associated with B. brizantha; pigeon pea; millet; Panicum maximum; sorghum; Stylosanthes guianensis; and Crotalaria juncea. The first seven crops had been cultivated in summer season since December 2001 and C. juncea since November 2003. In the winter season, after cover crop desiccation, irrigated common bean crop under no-tillage was planted. In February 2006, soil organic matter content, some soil physical attributes, and soil physical quality measured by S index were determined. Cover crops, especially grasses, favored soil aggregation at the surface layer. Soil cultivation modified its structure in comparison to native forest, increasing bulk density and reducing macroporosity, total porosity, and soil physical quality. Among the cover crops, pigeon pea, C. juncea, and corn associated with B. brizantha were those that maintained soil surface layer with good physical quality.
Phaseolus vulgaris; physical attributes; S index; center pivot; cerrado
