Evaluation of anthropogenic sustainability of agro-gray forest soil in intensive agriculture by change of its biological activity indicators

Kazan State Agrarian University, 420015 Kazan, Russia

^* Corresponding author: gaffarovalylya@mail.ru

Abstract

Studies have been carried out with the identification of criteria for the anthropogenic stability of agro-gray forest soils according to the main indicators of biological activity under conditions of intensive farming. Soils of this type are dominant in the soil cover of the Republic of Tatarstan, so the results of the experiment can be widely interpolated to similar conditions of soil formation and serve as quickly defined markers for diagnosing anthropogenic pressure. Studies have been carried out in field crop rotation since 1992, using various doses of potassium at three levels of soil nitrogen supply. As a result of long-term use of fertilizers, changes in microbiological activity have been revealed, in the variant with the use of environmentally balanced doses of mineral nutrition, an increase in microorganisms from 3,400 thousand (control) to 4,000 thousand per 1 g of soil is observed. A subsequent increase in the dose of fertilizers led to a decrease in the number of microorganisms relative to the control. Under the influence of the optimal combination of fertilizers (option 3), conditions for the development of actinomycetes, ammonifiers, nitrifiers, cellulose-decomposing bacteria are improved, while very high doses of mineral fertilizers (N₁₈₀P₆₀K₂₀₀) worsen them, indicating a decrease in the activity of beneficial bacterial microflora. This leads to a slowdown in decomposition of fiber, nitrification and other biochemical processes. Indicators of the biological activity of the soil correlate among themselves, as well as with other indicators of its fertility, with the productivity of crop rotation and therefore can serve as an additional diagnostic sign when assessing the anthropogenic stability of the agricultural soil of the agricultural soil in intensive agriculture.