Micromorphological and physical properties of southern ravine soils in Dnipropetrovsk region

摘要

The article contains the results of determination of physical and micromorphological properties of soils under natural ravine vegetation in the southern part of Dnipropetrovsk region. The value of ravine forests for the steppe zone of Ukraine is analyzed, and the methods of investigation are shown. Forest typology characteristics of the vegetation stationary test areas, as well as macro- and micromorphological characteristic of the soil profile, structural condition of the soil, its aggregate composition, and water stability of aggregates, are determined. Soil-forming processes in ravine ecosystems of the southern variant in Dnipropetrovsk region are diagnosed. Micromorphological studies of soil in the intact state, as well as analysis of produced thin sections, revealed the high degree of aggregation of the upper (0–60 cm) soil horizons. Structure formation is of zoogenic origin. Large amount of soil aggregates of coprolite structure is clearly seen under the microscope. Well decomposed plant residues are visible in the aggregates. Soil over the entire area of the section is of dark brown, almost black color. This is due to the large amount (80%) of organic substances indicating the active processes of humification. Fine grained humus is represented by plenty of equally spaced bunches of humones. Humus is in mull form. Skeleton is composed of different sized minerals, with quartz and feldspars dominating in its structure. Plasma is of humus-clay type, uniform over the entire area of the section and anisotropic with point illumination. Visible pore surface area is significant (65%) in the upper layers of the soil profile. Pores feature round and oblong regular shape. Often (on 50% of the pore area) the outbreaks of small invertebrates are found. With the depth of the soil profile, visible pore area decreases, as well as the aggregation. While correlating with the micromorphological characteristics, water stability of the soil structural aggregates reaches very high (80%) indices in the upper horizons of the soil profile and gradually decreases with the soil profile depth. Active biogenic microstructure formation, defining significant aggregation and looseness of microstructure, was diagnosed.?.