The no-tillage system improves the structural soil quality. However, machinery traffic can cause surface soil compaction. In this situation, soil tilling for lime incorporation not only corrects soil acidity problems, but also decreases possible negative effects of soil compaction. The effects of tilling or not tilling the soil at the moment of lime reapplication on physical attributes in the soil profile and crop yields under different soil management systems were therefore evaluated. A long-term experiment was conducted on a Rhodic Paleudult (Ultisol) at the Agronomical Experimental Station-UFRGS, in Eldorado do Sul, Rio Grande do Sul State, Brazil, during 12, 8 and 4 years under no-tillage and 12 years under conventional systems. The soil physical attributes (bulk density, porosity and aggregate stability) and organic carbon content were evaluated in three (0-2.5; 2.5-7.5 and 7.5-15.0 cm) soil layers, four years after soil mobilization for lime incorporation. Corn and black oat + vetch yields were also determined. The measured soil physical attributes returned to the original condition after four years under no-tillage. The soil physical attributes were more uniform in the conventional tillage, but with a lower aggregate stability in the surface layer in comparison to the no-tillage treatments. The observed differences in the soil physical attributes were not enough to affect corn and black oat + vetch yields.
soil tillage; aggregation; corn; oat + vetch
