Soil physical attributes and organic matter accumulation under no-tillage systems in the Cerrado

Soil management has a major effect on soil physical characteristics, and consequently on soil organic matter (SOM) content, which are important for the success of crop production. The aim of this study was to evaluate the soil physical attributes and the accumulation of SOM in no-tillage systems (NTS) with different periods of implantation in a conventional tillage area and to compare them with native forest (NF) in the Cerrado biome. The experiment was planned in a 3 x 4 factorial scheme, consisting of three soil treatments (NTS for 17 years (NTS17), NTS for 5 years (NTS5) and NF) and four soil depths (0-0.1, 0.1-0.2, 0.2-0.3 and 0.3-0.4 m), with a completely randomised design and four replicates. At deep soil layers (0.2-0.4 m) the NTS17 area had a greater soil density than the NTS5 and NF areas, and greater SOM compared with the NTS5 area. Soil macroporosity in the NTS5 area was below 10% at all soil depths evaluated. The NF area had the greatest total organic carbon content (1.39 dag kg(-1)), stock of carbon (16.63 Mg ha(--1)), amount of soil organic matter (28.66 Mg ha(--1)) and equivalent carbon credits (60.96 Mg ha(-1)). Carbon stocks were similar in the NTS areas in all soil depths evaluated. The results indicate that conventional tillage areas can be successfully recovered under the Cerrado edaphoclimatic conditions with the implantation of an NTS.