Disponibilidade e aplicabilidade de dados espaciais na caracterização e quantificação de perdas de solo por erosão na bacia hidrográfica do Rio Samambaia, Goiás

• Autor(a) principal: Botelho, Thiago Henrique Arbués
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/5648
• topic: Modelagem espacial; Fator topográfico; Conservação do solo; USLE; Spatial modeling; Topographic factor; Soil conservation; USLE; CIENCIAS AGRARIAS::AGRONOMIA

The monitoring of soil loss by erosion is a source of information relevant to land management, forecasting impacts and conservation recommendations. In this sense, the objective of this study was to apply computer simulation methodology of soil erosion using the Universal Soil Loss Equation (USLE) and sources of information available to characterize, quantify and analyze soil losses in the Samambaia River watershed (BHRS). This basin was chosen as the study unit, due to the availability of spatial data in different scales (1: 250,000 and 1: 10,000). A Geographic Information System (GIS) was used in handling, sorting and updating of data of interest as well as to build the Digital Elevation Model (DEM) and the spatial database of USLE factors in two different scales. To quantitatively analyze the results calculated the Natural Potential Erosion (PNE) and the current erosion (Ea) that considers the influence of coverage, Land Use and Occupancy (UCS), also used for qualitative studies of soil losses. The study area was divided into three sub-basins. The mapping of the UCS showed that agricultural areas represent about 70% of land cover in the sub-basin of Samambaia River and Arrasta-burro Stream. The results indicated that more than 80% of the area of these two sub-basins has a weak PNE. Have the sub-basin of Moreira Stream had the highest percentage of natural vegetation and forestry classes, as well as the lowest percentage of bare soil class, in relation to other sub-basins. However, had the highest average value of current erosion (71.10 Mg ha-1 yr-1), which is probably due to the PNE ranging from moderate to very strong in more than 40% of the area. Most of the basin soil has medium erodibility. For Cambisols and Petric Plinthosols of BHRS, the average soil loss is at least twice higher than the average level of tolerance. The LS factor has more influence in the PNE, especially when the relief was wavy, followed by the K factor, when the relief was flat. Use the database scale 1: 10,000 affected area of the watershed caused increases in slope and rise of strong corrugated relief classes, mountainous and rugged, yet showed higher coefficients of variation for all the factors of USLE. The results show greater difference between the wavy relief classes in both applied scales. In most maps produced by means of databases on different scales there is distinction of the results, especially for the slope maps, PNE and Ea generated for the watershed of the Samambaia. The analysis of soil losses in the areas of central pivot showed higher average and median values when using the scale 1: 250,000. It is important that managers and farmers are aware of the risks and provide mitigation measures. An interesting solution is to expand the use of lower impact to soil management systems, to promote its wider coverage, such as forestry, especially in the areas susceptible to erosion.