Soil and water loss in Ultisol of the Cerrado-Pantanal Ecotone under different management systems

Soil and water losses were evaluated in dystrophic ultisol of the Cerrado-Pantanal Ecotone cropped with common bean, Phaseolus vulgaris L, under different tillage systems. The treatments studied were conventional tillage with primary and double secondary disking (CT), minimum tillage with chisel plow (MT) and no-tillage (NT) systems, the last associated to 4 crop densities: 0, 3, 6 and 9 Mg ha-1. In order to characterize the experimental area, analyzes of water-dispersible clay, flocculation degree, aggregate stability, soil bulk density, soil porosity, soil moisture and surface roughness was carried out. Using the portable rainfall simulator, the plots received application of rainfall of 60 mm h-1 to evaluate soil and water loss. The treatments were arranged in a randomized block design with four replications. The soil losses ranging from 11.38 to 380.56 × 10-3 kg m-2, while water losses ranging from 4.15 to 31.57 × 10-3 m3 m-2. The highest soil losses occur in CT and the lowest water losses in MT. In NT, the highest level of crop residue deposition on soil surface reduces soil and water loss. Compared to water loss, soil loss is more susceptible to variations in the type of tillage system and levels of plant residues.   Key words: Water erosion, soil conservation, simulated rainfall.