All anthropic action causes changes in the environment. The objective of this study was the evaluation of alterations on the physical properties of a typical Brazilian Oxisol, caused by agricultural soil management. Undisturbed soil samples were collected along a 1m top layer of the soil profile in three use and management systems: natural forestry, non-irrigated and irrigated. These samples were used to determine the soil water retention curves and then the soil pore size distribution. After flooding, the aeration porosity was determined in a field plot during the water redistribution period in relation to the calculated total soil porosity. Results indicated that the soil management affected bulk density down to a soil depth of 0.4 m and, consequently, soil pore size distribution and aeration porosity as well. Bulk density values above 1.2 Mg m-3 caused deficiency in the root aeration system for periods above 24 hours.
no tillage; soil compaction; soil management