Quantifying soil erosion and sediment yield in a catchment in southern Brazil and implications for land conservation

Although agriculture represents about 30 % of Brazil's GDP, there are few data at the catchment scale on land use, soil management, hydrology, and water quality. This study aimed to investigate the connections between current soil management practices in the southern Brazilian Plateau and their impacts on soil erosion, sediment yield, and streamflow. The monitoring was performed in a rural catchment with significant evidence of soil erosion and surface runoff despite widespread use of no-till. Streamflow (Q) and suspended sediment concentration (SSC) were measured over 2 years (2011 and 2012). The study shows that elevated gross erosion values in the catchment are associated with areas of potentially high surface runoff and low soil infiltration, possibly caused by inadequate soil management practices and excessive soil compaction. It was also noted that a large area in the catchment had higher soil loss rates than the limits considered acceptable for both the region and the tillage system. Results indicate that there are significant environmental problems associated with surface runoff and sediment yield under the no-till system of soil conservation as currently practiced in this catchment.