The aim of the research is to study stability of ravine slopes at early stages of soil development for substantiation the stability and landscaping of ravines. Investigation methods were laboratory analysis of soil samples, study of the surface runoff and erosion at ravine slopes. We have found that overgrowing during 25–30 years of the loose rock at ravine slopes led to the development of early stages of soil ontogenesis. This causes talus of fine particles of the surface soil layer at the edge of a ravine, as well as specifics of soil formation under the influence of permanent grass cenosis or woody vegetation. At the same time parent material changes its micro-aggregate content, enriches by humus, and gains other favorable properties. Aggregation of textural elements with increasing of humus content declines soil density and enlarges porosity and water-resistance of soil structure. During the period of 25–30 years permanent grasses can accumulate at the slopes 5.5 t/ha of their air-dry weight, woody vegetation – 13 t/ha of forest litter. At the age of 15–20 years of overgrowing at the slopes formed embryonic soil, and soil erosion is completely absent. The general index of slope stability (independent from the vegetation type) is humus content (more than 2.5 %) in the top soil layer. At humus content less than 2.5 %, erosion occurs if runoff coefficient exceeds 0.21. The research identified that stability of ravine slopes increased during overgrowing at soil formation. This enables to substantiate activities for providing stability and landscaping of ravines.
Keywords: ravines, slope overgrowing, soil ontogenesis, soil properties, soil erosion.
