The size distribution, the quantity and stability of soil aggregates are important parameters to evaluate the soil structure, which plays a relevant role in soil-plant relationships. Vinasse when applied on soil stimulates microbial activity because of its organic matter content. This activity may increase mucilage production and improve the aggregation and soil structural stability. The objective of this study was to evaluate the aggregate stability in an Oxisol treated with different vinasse doses. The study was carried out at the Londrina State University Exerimental Farm from August 1997 to August 1999, in randomized blocks, with five treatments (vinasse doses) and four replications. The soil samples were collected in four soil layers (0-10, 10-20, 20-30 and 30-40 cm). The evaluations of this study were carried out at the fifth harvest (fourth ratoon), in August 1999. Vinasse was applied at 0, 150, 300, 450 and 600 m³ ha-1 and the following aggregation indices were determined: Ponderate Middle Diameter (PMD), Geometrical Middle Diameter (GMD) and Aggregate Stability Index (ASI). The results showed that different vinasse doses did not significantly alter the aggregation indices of the different depths studied.
soil physics; aggregation indices; organic matter
