Estimativa da erosão hídrica na sub-bacia hidrográfica do Córrego Pedra Branca, município de Alfenas - MG, a partir da Equação Universal de Perdas de Solos Revisada

Abstract

The Latosoil (oxisols) class is the most used on agriculture on South of Minas Gerais. Its weathering features, the physical and chemical properties and its mineralogical composition provide high stability to these soils. Such peculiarities contribute to decrease the erosive action of the rainfall, resulting in deep soils and well structured. However, in the last 100 years, cultives and managements have submitted these soils to practices that expose them to the hydric erosion. This occurrence degrades their attributes and favors the erosion increase, promoting the water bodies’ silting on the region. To estimate the water erosion in the watershed Córrego Pedra Branca, we applied the revised universal soil loss equation. In the watershed were discriminated three units of dystrophic Red Latosols ((LVd1, LVd2 and LVd3) were discriminated and one of undiscriminated floodplain soils (SIV), which present an average soil loss of 4,7 t ha-1 year-1 were evaluated. Of the total area, 31,7 % of the watershed presented erosion levels above the limit of loss tolerance as follows: 10,54 t ha-1 year-1 for LVd1; 9.35 t ha-1 year-1 for LVd2; 9,14 t ha-1 year-1 for LVd3; and 9.77 t ha-1 year-1 for the SIV. The area with erosion rate above the tolerance limit resulted from the management, the absence of conservation practices and high erosivity. However, in a simulated scenario with conservation management practices, such as no tillage, average soil losses would decrease to 1,38 t ha-1 year-1, with only 3,93 % of the area with soil losses above the tolerance limit.