This article describes a study that analyzes the impact of a tillage chronosequence on concentrations of soil organic carbon and its interactions with soil fertility in a Brazilian Oxisol. As land is converted from natural ecosystems to cropland, the properties of the soil are significantly affected. Moreover, as crop cultivation is intensified to a large scale, the methods used can be detrimental to the nutrient levels in the soil. This study suggests that long-term no-tillage is a useful strategy for improving fertility of soils with variable charge.