Evaluation and quantification of soil use impact on its physical quality are important to achieve sustainable cropping systems. Soil physical attributes were assessed after twenty years of implementation (1985 to 2005) on a typical Dystrophic Red Latosol (Rodic Hapludox) located in Passo Fundo, Rio Grande do Sul State, Brazil. Four soil tillage systems were evaluated: 1) no-tillage; 2) minimum tillage; 3) conventional tillage using a disk plow plus disk harrow, and 4) conventional tillage using a moldboard plow plus disk harrow. Three crop rotation systems were evaluated: I (wheat/soybean), II (wheat/soybean and common vetch/corn or sorghum), and III (wheat/soybean, common vetch/corn or sorghum and white oats/soybean). A randomized complete block design, with split-plots and three replicates, was used. The main plots were formed by the soil tillage systems, while split-plots were composed by crop rotation systems. As control, soil samples were collected in a subtropical forest fragment adjacent to the experiment. Soil tillage systems and crop rotation systems influenced soil physical parameters when compared to the samples collected in a fragment of subtropical forest. During four years (2001 to 2005) the physical attributes were altered among different soil tillage management. The no-tillage system (PD) presented higher soil bulk density and microporosity in comparison to the other systems, mainly in 0.10 to 0.15 m layer, characterizing high soil compaction levels. Crop systems did not promote favorable changes in physical attributes independent of the type of soil management.
no-tillage; soil bulk density; total soil porosity; soil microporosity; soil macroporosity
