ATRIBUTOS FÍSICOS DO SOLO E TEOR DE CARBONO ORGÂNICO EM SISTEMAS DE PLANTIO DIRETO E CULTIVO MÍNIMO

Conservationist management systems of soil aim at creating propitious conditions to develop crops, allowing an efficient control of erosion and a correct maintenance of soil and water, due to erosive effects minimization. On the other hand, there are some changes on soil structure which show the importance of comparative studies that determine a better management in order to improve productivity and economy of natural and financial recourses. The physical properties on no-tillage (NT) and minimum tillage (MT) management systems were analyzed in an experimental area in Foz do Iguacu, Western of Parana, whose production has been carried out during five years under NT system. It was an Alfisol soil. Samples were collected before wheat seeding and after its crop to registered particles densities, soil density, total porosity, textural density and organic carbon content from soil on the following depths: 0.00-5; 0.05-0.10; 0.10-0.15 and 0.15-0.20m. Textural density supported the answers for determining values concerning the saturation limit status (only water, without air) and water and air retention limit, related to friability range (adhesion x cohesion) and a better stability of aggregated to each analyzed depth. The NT system showed greater organic carbon content and the least result of total porosity at 0.0-0.05m of depth. The particles density results increased with depth and total porosity, while MT system showed greater answers of porosity on upper layers, even though it contributed on reducing soil porosity from 0.10-0.15 and 0.15-0.20m layers of depths.