Avaliação de perdas de solo em estradas florestais não pavimentadas no Vale do Rio Doce, Minas Gerais

Abstract

In the forest sector, the road network is the main basis of all the forest activity; however, the forest roads have been one of the main causes of erosion and silting of water courses in planted forests. Therefore the present work aimed to evaluate the soil losses by sheet and rill-erosion in unpaved forest roads and displacements of soil masses on hillsides and embankments, at the Rio Doce Valley, Central-East region of Minas Gerais State, Brazil. The results indicate that the average soil losses amplitude was 68.3 kg m-2 in the 0–4% slope class, and 142.4 kg m-2 on slopes above 12%. The highest average water losses occurred on unpaved forest roads, while on better soil protection (legal and permanent reserves), the water losses were only 1.4%. On the hillsides and embankments the average soil loss was 820 kg m-2. The major part of the sediments originated from the displacements of soil masses; however unpaved forest roads also had high soil loss values. These results suggest a need for better practices to control forest roads erosion and keeping vegetated embankments to avoid soil and water loss and siltation of reservoirs and rivers. Furthermore, a proper design of road network should be performed to fit the terrain topography