The purpose of this work was to evaluate the effect of soil management systems in the aggregate stability. The soil of the experimental site, classified as an Alfisol, according to the Brazilian System of Soil Classification, is located at the Lageado Experimental Farm, FCA/UNESP, in Botucatu - SP (Brazil). The effect of management practices was evaluated in the following treatments: native forest (MA), continuous conventional tillage for ten years followed by no-tillage for twelve years (PC/SD) and continuous conventional tillage for twenty two years (PC). The soil was sampled in four layers: 0.0-0.10; 0.10-0.20; 0.20-0.30 and 0.30-0.40 m. Soil samples were collected from each treatment in October 2001. The experimental design was completely randomized with three replicates. The wet soil aggregate stability was expressed as mean weight diameter (DMP), aggregate stability index (IEA) and percentage of aggregate size class. The DMP and the IEA were greater to the soil under native forest and conventional tillage/no-tillage. The three management systems presented larger aggregate percentage with diameter between 7.93 and 2.00 mm. The change from conventional tillage to no-tillage improved the soil aggregate stability. The mean weight diameter, the aggregate stability index and the percentage of aggregate size class evidenced differences among the soil management systems.
mean weight diameter; aggregate stability index; and no-tillage
