Results of soil microbial community study at the Siberian Research Institute of Soil Management and Chemicalization of Agriculture

Abstract

Resulted from long-term (1986-2014) studies, the causes and eco-toxicological effects of changes in biological properties of soils were established regarding leached chernozem of areas near the Ob under conservation farming system and regulation of soil organic matter content by changing plant residues amount. The three new methods were developed to evaluate parameters of biological activity of soil. When discontinued plowing, the natural stratification process in the root layer was found to rise about 3 times as compared with plowing; rate of the mineralization processes decreased (respiratory activity by 10%, nitrification by 20%) that contributed to forming microbiological prerequisites for deterioration of nitrogenous nutrition of grain crops. A comparative analysis showed that the negative, from the farming position, microbiological processes in leached chernozem of areas near the Ob under conditions of reduced tillage were more pronounced as compared with soils of the southern regions. However, when the tillage minimization levels studied such as alternation of plowing and subsoil tillage, deep subsoil tillage, shallow blade cultivation, no-tillage, and others were applied, the increases in lengths of minimization did not accompanied by deepening of the processes above, and crop productivity did not depend on a tillage method under conditions of mineral fertilization. The eco-toxicological safety of long-term reduced tillage of leached chernozem down to complete refusal to till has been proved. The new methods have been developed, which allow calibrating a relationship between detoxification capacity of soil and organic matter content that enables not only to trace this environmentally significant function of soil but also to evaluate new agricultural technologies.