Assessment of ecological efficiency of the scheme of agrolandscape formation at the level: system of gullen drainage areas → gullen drainage area of the Aidar River

Abstract

Goal. To assess ecological efficiency of the scheme of formation of agrolandscapes at the level: system of gullen drainage areas → gullen drainage areas of the Aidar river. Methods. Laboratory-field, mathematical-statistical, topometric, morphological. Results. The basic erosion-ecological situation of the object of research is determined. PS levels are calculated for the Steppe zone. An Integral map of soil erosion hazard classes of the Steppes of Ukraine is constructed. At the level of the system of gullen drainage areas of the Aidar River, the analysis is carried out of the nature of the impact of forecast and actual erosion-hydrological indicators (runoff costs) on the development of erosion-hydrological processes on a probabilistic basis (1; 5; 10; 50%) by their ratio. On the example of the Yevsuh and Kovsuh river basins, plowing indicators are calculated for key drainage areas along the river with differentiation of administrative land use. The map of the structure of the Yevsug and Kovsug river basins within the drainage areas is constructed. The structure of sown areas and their plowing is assessed according to the potential runoff indicator: up to 5 mm — insignificant, 5.1–8 — weak, 8.1–15 mm — moderate, with erosion index levels (3 and lower; 3–4; 4–5; 5 and above) and grouping the structure of sown areas. According to the simplex method, the analysis of actual and forecast erosion-hydrological indicators and optimization of the structure of sown areas is carried out. For the Aidar River basin the model structure of crop rotations is obtained. Ecological assessment of the structure of crop rotations is performed according to the coefficient of ecological danger of crop rotations. Conclusions. At the level of the gullen drainage areas system, the coefficient of the ratio of KV of forecast and actual losses of the river runoff as an indicator of the development of erosion-hydrological processes on a probabilistic basis (1; 5; 10; 50%) at hydro-posts along the Aidar River showed that at 10% security in case of reduction of plowed lands to 50–60%, a high level of runoff reduction (81–90%) was observed at the Bakhmutivka hydro-post, medium (73–85%) — at Bilolutsk and Starobilsk hydro-posts, the lowest — at the Kuriachivka hydro-post (39–65%). The study of humus content in the range of 4.5–5.5% by groups of arable land areas 40–60% revealed constant decrease in Qmax (average maximum runoff losses) in the range of 8–9%. At the level of individual gullen drainage areas, the determination of the basic erosion-ecological situation of the object of research on the integrated map of erosion hazard classes of steppe soils of Ukraine showed its belonging to the class of moderate erosion hazard with runoff of 8.1–15.0 mm.