MICROBIAL BIOMASS AND ASSESSMENT OF AGROSOIL SUSTAINABILITY WHEN USING VARIOUS PROCESSING TECHNOLOGIES

The aim of the study was to assess quantitative changes in microbial biomass carbon, basal respiration and stability of agrochernozem (based on the metabolic quotient) using moldboard and surface tillage methods in the Krasnoyarsk forest-steppe. Observations were carried out in crops of a production experiment laid out in the Shilinskoye agricultural production cooperative in the Krasnoyarsk forest-steppe (56°37’ N; 93°12’ E). The object of the study was leached medium-humus medium-deep highly eroded light-clayey chernozem on red-brown clay, which was characterized by: average humus content of 5.9 %, neutral reaction (pHH2O = 6,8 = 6.8), high sum of absorbed bases – from 60 to 62 mmol/100 g of soil. Field observations were carried out in the following variants: 1) autumn plowing (moldboard); 2) surface disking; 3) zero technology. The dynamics of microbial biomass carbon during the observed periods had a multi-peak character with predominant maxima in midsummer. Over the years of observations, the factor "timing" turned out to be a reliable determinant of the content of microbial biomass carbon (40.8 % of the total variance). The formation of the microbial carbon pool was determined by the factors "cultivation methods" and "interaction". Their total contribution was 71 %. The basal respiration rate was reliably high under moldboard plowing conditions. Activity peaks occurred both at the beginning and at the end of the growing seasons. The main influence on the intensity of carbon dioxide production was exerted by temperature (r = 0.74) and soil moisture (r = –0.77). The values of the metabolic coefficients indicated the absence of "stress" disturbances in the microbial community under the conditions of the applied methods of processing agrochernozems.