Variability in soil physical properties in landslide-prone areas/ Variabilidade dos atributos fisicos do solo em areas suscetiveis ao deslizamento de terra

The present study aimed to evaluate the relationship between the physical properties of the soil and relief in areas that are susceptible to landslides in the sub-basin of the Corrego do Yung, a creek in the urban district Tres Moinhos of Juiz de Fora, Minas Gerais. Depth measurements of the solum were made at the soil sampling points, and the subsurface material was collected and analyzed for the two factors of particle size and type of horizon. In the laboratory, we determined the hydraulic conductivity, bulk and particle density, and total porosity, macroporosity and microporosity. The values of the physical properties throughout the sub-basin were predicted and mapped. Thematic maps were generated and showed a relation to each other: the clay was related to a higher hydraulic conductivity, higher porosity and lower soil density. In the steeper areas, the greater silt contents were mapped in the deeper layers and indicated the thin thickness of horizon B in these areas. A close relation of the curvature with the soil thickness was detected and was greater in the flat areas with less slope. The geostatistical analysis showed that the range of values for the properties of macroporosity, microporosity and silt was the lowest in the deeper layers, indicating low structural continuity in potentially erodible areas. Keywords: physical soil, geostatistics, landslide. Objetivou-se avaliar a relacao entre os atributos fisicos do solo e do relevo com as areas suscetiveis ao deslizamento de terra na sub-bacia do Corrego do Yung, localizada no bairro Tres Moinhos em Juiz de Fora, Minas Gerais. Foram locados os pontos de amostragem e procedeu-se as medicoes da profundidade do solum e coleta de material subsuperficial, observando-se dois fatores: granulometria e tipo de horizonte. Foram determinadas, em laboratorio, a condutividade hidraulica, densidade do solo e de particulas, porosidade total, macroporosidade e microporosidade. Realizaram-se as interpolacoes para predizer e mapear os valores dos atributos fisicos em toda a sub-bacia hidrografica. De acordo com os mapas tematicos, a textura argilosa relacionou-se a maior condutividade hidraulica, maior porosidade total e menor densidade do solo. Nas areas mais ingremes, foram mapeados maiores teores de silte em profundidade, representando a pequena espessura do horizonte B. Verificou-se estreita relacao da curvatura com a espessura do solo, sendo os mais profundos localizados em areas planas e de menor declividade.