Soil Physical Attributes in Agricultural Systems With Conventional Tillage and No-Till, and Crop Rotation in a Xantic Hapludox in the Savanna of Roraima.

The use of natural resources converted to shifting cultivatrion has led many areas to degradation process that result in different types of environmental problems. The aim was to evaluate the effects of two types of soil management and crop rotation on soil physical and chemical quality of a Dystrophic Yellow Latosol (Xanthic Hapludox) in the savanna of Roraima. The experiment was split plot design with four replications in tillage (CT) and no-tillage (NT). Four treatments represented by four crop rotations, and a natural area. Soil samples were collected at four different depths, from 0.0 to 0.05 m, and 0.05 to 0.10 m, 0.10 to 0.20 m, and 0.20 to 0.40 m. The crop rotations were described as follows: T1 - Corn → soybeanà (cowpea + corn) → corn à soybean; T2 - quicuio grass → soybean→ (cowpea + corn) → soybean→ millet, T3 - Brachiaria → soybean→ corn → soybean; T4 - Brachiaria → soybean→ (cowpea + corn) → corn→ soybean. Principal Component Analysis (PCA) was performed and verified by contrasts the savanna and CT, and savanna and NT area. There were significant changes in the attributes of the soil depths 0.0 -0.05 m and 0.05 – 0.10 m caused by different soil management compared to uncultivated savanna. There was significant difference between soil management systems, crop rotation and depths. Soil physical and chemical attributes showed significant interaction between crop rotation and depths. According to the results, the conventional tillage, the no-tillage, and crop rotation improved the soil physical and chemical attributes compared with savanna. We can conclude that no-tillage could be an alternative to maintain or improve soil fertility and provide a lower cost in driving cultures to less environmental impact in the Roraima savannas.