Stock of carbon in a Rhodic Acrudox under different management systems

Abstract

The introduction of agriculture in areas with native vegetation generally results in a rapid loss of organic carbon in tropical environments, resulting in decreased soil quality. Thus, the objective of this study was to evaluate changes in carbon stocks and in some soil physical characteristics (bulk density - BD and total pore volume - PTV) under different management systems in the ‘Cerrado’ region of Goiás State, Brazil. With this purpose, areas with four different management systems were selected in the Rio Verde municipality: no-tillage system with three years of implantation (NTS-3); conventional tillage system (CTS); and planted pasture with Brachiaria brizantha (PP). These areas were compared to an area of native ‘cerrado’ “stricto sensu” (NC). In each one of these areas soil samples were collected at 0-5, 5-10 and 10-20 cm depths. The design was completely randomized, with five replications. The areas of NC and CTS had at all analyzed depths lower values of BD, and greater PTV in relation to the areas of PP and NTS-3. The NC presented carbon contents and stocks similar to the NTS-3 areas and greater the PP and CTS. These results showed that the NTS-3, characterized by the maintenance of plant residues on the soil surface, crop rotation and minimal soil disturbance (tillage only in the line / tree planting), contributed to increase or to  maintain soil carbon stocks.