Количественная оценка потерь почвы вследствие водной эрозии на сильновыпаханных почвах бассейна верхней Оки с использованием географических информационных систем

Abstract

The paper presents some results of studying soil losses appearing due to water erosion in an agricultural field with highly degraded plowed soils. The research was carried out on the arable slope of the southern exposure in an experimental area located in the Oryol district of the Oryol Region (upper Oka basin). A set of methods was used: morphometric analysis of the topography relief, radiocaesium method, soil-morphological method, method for determining easily decomposable organic matter (labile organic matter) designed according to Ganzhara and Borisov, agrochemical methods. The study was based upon the authors’ in-situ data of 2016–2023. Maps are compiled to show the caesium-137, humus and labile organic matter spatial distribution, and of the soil degradation degree (in points on the Ganzhara and Borisov scale) in the arable horizon of 0–25 cm. Analysis of the caesium-137 radioactivity spatial distribution made it possible to identify two sectors in an area of highly degraded plowed soil, which differ in surface slope values and in nature of the caesium-137 radioactivity interdependences with catchment area and sign of profile curvature. Developed semi-empirical computational dependences for the delineated sectors allow to compile a gridded map of the soil runoff intensity (in t/ha/year). The intensity of soil runoff in the area with highly degraded plowed soils is ranged from 5 to more than 20 t/ha/year. The algorithm for the intensity of soil delivery outside of the studied area was developed on the basis of layer-by-layer soil sampling data collected in the mouth of the ravine, removing soil from the highly degraded plowed soil area. The algorithm showed that 4.7–6.5 tons of soil per year are removed from 1 hectare of the catchment area basin. The rest of the outwashed soil material is deposited in accumulation areas within the catchment area basin. The authors recommend verifying the findings in other areas of the agricultural field. The proposed methodology for soil loss estimation, developed for highly degraded plowed soil areas in an agricultural field, requires clarification by enlarging the scale of the study.