Microbiological activity of chernozem depending on the use and size of soil aggregates

Abstract

The results of the studies of changes in biological and enzymatic activity of soils depending on the anthropogenic influence and the size of soil aggregates are presented. The work was carried out in 2015-2021 in the conditions of the south-east of the Central Chernozem region. The soil of the experimental site is ordinary (segregational) medium–sized medium-humus heavy loamy chernozem. The objects of research are long–used arable land and the layland used for haying since 1882. The quantitative change of individual groups of microorganisms, determined by the nature of the impact on the soil cover, is shown. The total number of microorganisms in both arable land and chernozems under natural vegetation was at the same level of 40.0 and 39.3 million CFU, respectively. Significant differences in the biological activity of chernozems by individual groups of microbial cenosis structure were noted. An increase in the number of ammonification bacteria on the arable analogue was revealed by an average of 30.7%; micromycetes by 4.4%; cellulolytics by 46.4%; nitrifiers by 46.9%; calculated humification coefficient by 45.4%. According to other components of microbial cenosis, the advantage of layland steppe soils is noted: actinomycetes by 18.5%; humus mineralizers by 11.8%. An increase in the activity of most groups of microorganisms was shown in the smaller structural units of 1-5 mm. In larger mesoaggregates, CFU numbers tend to decrease. This pattern is most clearly traced in agrogenically altered soils. In the soils occupied by natural vegetation, there is a higher activity of biochemical processes.