Zinn, Y: Soil organic carbon retention in the Brazilian Cerr

Because of its key agricultural and environmental importance, soil organic carbon (SOC) and its chemistry, stocks and dynamics have been extensively investigated throughout the world. In spite of all these research efforts, little is known about the specific mechanisms through which the soil physical matrix affects SOC retention and its properties. This paucity of such basic information is surprising, since mineral components comprise ca. 95% of the mass of most soils, the rest being composed by soil organic matter. Part of this scientific limitation is due to the fact that the predominant soil- and SOC-forming factors vary widely in number and intensity among the different climate zones, geological terranes and vegetation provinces of the World. In result, direct comparison of SOC studies and proper formulation of comprehensive theories and models become very difficult. This work has attempted not only to identify, but also quantify, the main edaphic controls on SOC retention in the Central Brazilian savannas (the Cerrados), aiming to help solving what was once called "the soil organic carbon conundrum".