Biological Activity of Sod-Podzolic Soils in a Long-Term Experiment Involving Various Agrotechnical Methods

Resumo

The effects from the multiyear use of grain–fallow–plow crop rotation schemes comprising legumes, permanent cultivation of winter rye and barley, and bare fallow regime on the ecological and physiological state of microbial communities in a sod-podzolic heavy loamy soil were examined in the course of a long-term, stationary experiment. Biological activity parameters of soil microbiocoenoses, including the potential intensity of CO₂ emission, microbial biomass gross respiration rate, metabolic coefficient, and nitrogen fixation, were assessed. It is shown that the application of organic fertilizers (manure) in the crop rotation scheme with 28.6% legumes ensures the best humus state of the soil and a significant increase in the total nitrogen content. It is established that the share of microbial biomass (C_mic) in the total organic matter of the sod-podzolic heavy loamy soil is 1.50–3.24%. The application of mineral fertilizers results in a slight decrease in the microbial biomass carbon content and increase in the labile organic carbon content. The metabolic activity of microbial communities decreases in all long-term experimental scenarios regardless of the land use techniques. The permanent intensive cultivation of crops, either with or without crop rotation, disturbs the microbiocoenosis stability in soils of the Cis-Ural region.