The no-till system have positive impacts in soil and water conservation. This work aims to evaluate the main modifications on the soil physical properties caused by no-till system, carried out during 3, 6, and 12 years under rainfed conditions. The cases of direct drilling for five years under irrigated condition, a conventional tillage system, and a soil condition under natural Biome Cerrado were also evaluated in the Ampessan farm, Cabeceiras, Goias, Brazil. The soil physical characteristics were evaluated by samples taken from the following layers: 0-5, 2.5-7.5, 5-10, 10-15, 20-25, 42.5-47.5 and 72.5-77.5 cm. The infiltration characteristics were evaluated at 12 and 80 cm soil depth, using the Guelph permeameter to determine the field saturated hydraulic conductivity. The results showed that the intense soil mechanization on irrigated condition favoured a significant decrease in the field saturated hydraulic conductivity in the layers near to the soil surface. There was a tendency for higher water availability in the cultivated soils, in relation to that under natural soil environment, up to 22.5 cm soil depth.
