The disposal of sewage sludge to agricultural soils has increcsing interest not only due to high costs and environmental impact involved in other methods of disposal, but also due to the necessity of disposal of increasing amounts of sludge from rural and urban sewage treatment. This study aims to evaluate the disposal of this residue on soil aggregation and its effect as soil conditioner, for use in recovering degraded areas. The experiment was set in the Central Experimental Center of the Instituto Agronômico, in Campinas-SP, on a clayed Oxisol that received sewage sludge in two rates, 10 Mg ha-1 e 20 Mg ha-1, for two years, what was compared to a control treatment, with no added studge. In order to evaluate soil aggregation, wet sieving method was used, measuring mean weighted diameter in two soil depths - 0,10 m e 0,20 m. The results showed significant difference among treatments with an increment on mean weighted diameter, and organic matter as rates applied increased. Sewage sludge acted as soil conditioner improving soil physical properties.
soil conditioning; soil physical properties; biosolid
