Assessment of the Impact of No-Till and Conventional Tillage Technologies on the Microbiome of Southern Agrochernozems

Abstract

Quantitative characteristics of microbial communities in southern agrochernozems of the Stavropol region managed with the use of no-till technology and moldboard plowing under different crops with and without application of mineral have been studied. The number of eco-trophic groups of microorganisms (nitrogen fixers, ammonifiers, denitrifiers, amylolytics, cellulolytics) was estimated using the classical method of inoculation on elective media; and the number of copies of ribosomal genes of archaea, bacteria, and fungi was determined using real-time polymerase chain reaction (PCR). The numbers of cultivated aerobic ammonifiers, denitrifiers, aerobic cellulolytics, actinomycetes, and micromycetes increase in the soils under conventional tillage, whereas no-till technology leads to an increase in the numbers of anaerobic cellulolytics and nitrogen fixers and aerobic diazotrophs and amylolytics. Corn stimulates the development of ammonifiers and amylolytics in the soil microbial community; soybeans, aerobic nitrogen fixers and aerobic cellulolytics; and sunflower, denitrifiers and anaerobic cellulolytics. The largest number of bacterial and fungal gene copies is characteristic of no-till plots and unmanaged long-term fallow, whereas gene copies of archaea have only been identified in the soil of long-term fallow. The data obtained attest to different directions and intensities of soil biological processes in agrochernozems under the conditions of no-till and conventional tillage technologies.