Natural Potential for Erosion for Brazilian Territory

Abstract

Erosion and sedimentation refer to the motion of solid particles, called sediment (Julien, 2010). Erosion is a natural process and causes a breakdown of soil aggregates and accelerates the removal of organic and mineral materials (Gilley, 2005). Soil erosion risk can be assessed by means of equations empirically derived from the superposition principle of this phenomenon. Using such models, during the last decade, several initiatives have assessed the risk of soil erosion at the national, continental, and global levels (Terranova et al., 2009). The use of geographic information system (GIS) enables the determination of the spatial distribution of the parameters of some soil loss predicting models, as the Universal Soil Loss Equation USLE (Dabral et al., 2008). Every factor within the USLE is calculated by GIS, which is obtained from meteorological stations, topographic maps, land use maps, soil maps and results of other relevant studies. The spatial distribution of the soil loss of a certain region is given by multiplying factor map layers in the GIS. The spatial resolution of the data is an option of researcher, and should be considered the resolution of the Digital Elevation Model (DEM), soil map, satellite images, among other sources of information (Yue-Qing et al., 2008). Land use is the only factor affecting erosion that can be modified to reduce soil loss potential (Gilley, 2005). However, if we do not consider the land cover and soil management, i.e., if we consider the interaction of rainfall, topography and soil, assuming that the soil is totally uncovered along wholly study area, we may predict the total soil loss amount or the Natural Potential for Erosion (NPE) for a considered area (Castro & Valerio Filho, 1997). NPE might be used as a tool to show cartographically areas highly pre-disposed to erosion and the mathematic relation among PNE value and soil loss tolerance value. It might indicate the ideal CP factor to be used in determined region. Brazil is largest South American country and the land use is far from to be conformable with land use capability. Hence, soil loss studies and researches are highly needed. On the other hand, a lot of studies have been developed in order to predict soil loss rates along Brazilian