The maintenance and improvement of soil quality are crucial to the stability, sustainability and productivity of natural ecosystems and agroecosystems. The understanding and quantification of the impact of tillage systems in their physical quality are fundamental in the development of sustainable agricultural systems. This study was carried out to evaluate the effects of management practices on physical properties and organic matter content of an Ultisol cultivated with cassava following the use of distinct cover crops. A field experiment was carried out in Glória de Dourados, Mato Grosso do Sul State, Brazil, in a sandy texture Ultisol. The following management practices were used: conventional tillage (SC), no-tillage system with cultural residues of Estilozobium pruriens (PDMu), Sorghum bicolor (PDSo) or Pennisetum glaucum (PDMi). A native vegetation (VN) soil was used as reference for comparison. Evaluations were performed in May 2003 (after planting cassava) and August 2004. Organic matter contents in the different soil management practices were similar. The effects of these systems on the soil physical properties were more pronounced in the early phase of cassava establishment. Aggregate stability was higher in cultivation systems that used grass as cover crop. Bulk density was lower and total soil porosity, particularly macroporosity, was higher in the conventional when compared to the no-tillage system using cover crops.
no-tillage system; conventional tillage; soil structure; soil aggregates; Manihot esculenta Crantz
