The objetive of this study was to evaluate the effect of management systems on soil organic matter contents. Soil samples were collected at 0-2.5, 2.5-5.0, 5.0-10.0 and 10.0-20.0cm depth in native grassland area and croplands under conventional and no tillage systems. Soil sample collected from a forest area were used as reference of the original soil condition of the region. The use of conventional tillage decreased soil organic matter contents approximately 60-70% in the 0-2.5cm soil layer, and approximately 50% in the 0-10.0cm soil layer, relativelly to the forest soil. The use of no tillage for 3-7 years resulted in increases of soil organic matter content of 25-108% in 0-2.5cm soil layer, and 18-52% in 0-10cm soil layer, comparativelly to the conventional soil tillage.
organic matter; soil management; soil conservation
