Pedogenesis and slope processes in subtropical mountain areas, Sierra Sur de Oaxaca, Mexico

Abstract

The study was conducted in a subtropical mountainous area of the Sierra Sur de Oaxaca, southern Mexico. This region has been reported to have a high diversity of soils due to erosion and deposition by slope processes triggered by seismic activity and rainstorms. In this study, lithologic properties indicate that 18 of 24 soil profiles received sediments as result of slope processes (landslides, colluviation, accumulation of the material washed out by sheet and inter-rill erosion). The profiles showing sediment deposition on the surface were formed on all landforms, except steep backslopes, where the loss of material is more intensive. The effect of newly accumulated sediment was previously underestimated, and varies from slight modification of soil properties to complete burial of a soil that forces pedogenesis to begin from “time zero”. Sediment accumulation due to slope processes should be included into a general pedogenic model for the study area.