The management and tillage change the soil structure, which in turn interferes with a series of physic-hydraulic properties in the surface soil layer. This work had as objective to evaluate chemical and physical-hydraulic soil properties that have implications on soil aggregation, macroporosity, and the available soil water in Red Latosol (Oxisol), either cropped under no-tillage or disk plowed for 20 years. The control was a native Cerrado (savannah) vegetation. Because of the absence of soils tillage and reduced machinery traffic, the no-tilllage system led to a decrease in macropore volume at a soil depth of 0-5 cm. However, this change caused no restriction to cultivation since the largest soil water availability at this depth had been observed in this system in comparison to the other studied systems. Soil bulk densities in the area under no-till, in the studied depths, were smaller or equal to those of the area under disk plowing, possibly due to the higher organic carbon content in that system and the absence of soil revolvement. The observed mean geometric diameters of aggregates up to 10 cm depth, in descending order, were found in soils under native vegetation (Cerrado), no-till, and disk plow. No significant differences were found at greater depths. At the 20-30 cm depth, disk plowing was the system that affected the Red Latosol structure the most, as indicated by the largest value of soil bulk density, smaller macroporosity, and a larger downward displacement of the characteristic soil moisture curve in the tension range of 0 to 6 kPa and upwards for tensions between 6 and 100 kPa.
soil-water retention; pore size distribution; no till; conventional till
