Fertility parameters and degradation processes of chernozems of the agricultural territory of Western Siberia

A brief overview of the fertility status of the main subtypes of arable chernozems in Western Siberia is presented. The main factors limiting the productivity of grain crops in forest-steppe and steppe climatic zones are considered. The features of potential and actual fertility for the chernozems of the eastern outskirts of the West Siberian province are shown, taking into account their humus state and the content of gross and mobile forms of the main plant nutrition elements. It was revealed that in order to obtain a stable crop of an intensive variety, it is necessary to apply at least 60–75 kg/ha, high-intensity – 95–130 kg/ha of full fertilizer (NPK). The lack of heat and moisture during critical periods of plant vegetation requires the use of balanced calculations of fertilizer doses to obtain the maximum possible, economically sound harvest. Under the influence of erosion, prolonged exploitation of soils without taking into account their provincial characteristics and compensation for the removal of NPK by commercial products, the water-physical, agrochemical properties of chernozems, as well as their ecological functions, deteriorate. Agricultural exploitation of non-eroded chernozems for >100– 120 years led to a decrease in the humus content in the upper layer by 0.8–1.9, nitrogen – by 0.1– 0.16 abs.% in comparison with virgin analogues. Crop yields decrease on slightly eroded soils by 10–20%, on medium-eroded soils by 30–40%, and on highly eroded soils by 50–80% compared with full-profile undisturbed soils.