PHYSICAL, CHEMICAL AND BIOLOGICAL PROPERTIES OF CERRADO SOIL UNDER DIFFERENT LAND USE AND TILLAGE SYSTEMS

As knowledge on no-till system expands, it has become quite clear that separate chemical indicators cannot provide a detailed soil characterization. The objective of this study was to evaluate the effects of tillage systems and soil use in the physical, chemical and biological properties of a clayey dystrophic Red Latosol - Oxisol and a sandy Neosol - Entisol. The treatments for the Oxisol consisted of: native savanna, pasture, conventional tillage, no-tillage with turnip and with forage sorghum as cover crop. For the Entisol: native savanna, native pasture, integrated crop-livestock, cultivated pasture, no-tillage with soybean and corn in the summer. Soil samples were collected from a depth of 0-10 cm, in a clayey dystrophic Red Latosol - Oxisol and a sandy Neosol - Entisol in a savanna ecosystem, near the Parque Nacional das Emas. Treatments were arranged in a completely randomized design, in 5 plots of 150m(2), where 10 sub-samples were collected randomly. Chemical, physical and biological analyses were carried out at a soil laboratory. In the Entisol, tillage influenced the soil density, total pore volume, macroporosity and penetration resistance. In the Oxisol, tillage induced variations in soil bulk density, macroporosity and penetration resistance. Small variations in chemical properties were observed in both soils, with higher potential acidity and lower exchangeable cation and phosphorus concentrations. The soil biological properties were influenced by tillage, and were most affected in systems with more anthropic action. In the canonical data analysis the greater weighting coefficient of the physical properties in the canonic variables demonstrated that these were the least important. The contribution of the separate soil properties to evaluate soil quality was minor, but the most sustainable management systems could be defined by multivariate analysis.