ASSESSMENT OF NITROGEN DIFFERENTIATION OF MICROBIAL BIOMASS IN AGRO-CHERNOZEM LAYERS DURING THE TRANSITION TO NONPLOW TECHNIQUES

Abstract

The objective of the study is to evaluate the heterogeneity of the compared soil layers in terms of the content of microbial biomass nitrogen under conditions of nonplow techniques of processing agrochernozems. The studies were conducted in the Krasnoyarsk Natural District based on a production experiment conducted on the land plots of the Shilinskoye agricultural production cooperative in the Sukhobuzimo District (56°37' N, 93°12' E). The soil of the experimental plot was leached high-humus medium-deep light clayey chernozem on red-brown clay. The experimental design included the following options (processing methods): 1. Zero. 2. Minimum. 3. Moldboard (st). The content of microbial biomass nitrogen (Nm.b.) was determined by the rehydration-extraction method. Differentiation of the studied soil layers by the value of nitrogen immobilization by microbial biomass was statistically significant in 67 % of cases and was more often observed in the first half of the vegetation seasons. It was found that hydrothermal conditions have a significant effect on the process of nitrogen fixation by microbial plasma. When using nonplow techniques of cultivation, the "temperature" factor was the most significant. In the 0–5 cm layer, when using surface disking, an increase in temperature was accompanied by remineralization of microbial nitrogen (r = –0.81...–0.97), and under no-till conditions – by its immobilization (r = 0.91...–0.96). Despite the relative homogeneity of the 0–20 cm layer during moldboard plowing, significant differentiation was found, which also indicated a significant role of abiotic factors in the assimilation of nitrogen by microorganisms. In general, the values of assimilated nitrogen by the microbial biomass of the studied agrochernozem indicate its significant reserves, which play an important agronomic role in the nutrition of agricultural crops.