Effect of Fresh Organic Matter of Straw on Microbiological Parameters of Soddy-Podzolic Soil

摘要

The loss of soil organic matter (SOM) due to agricultural land use has a negative impact on soil properties and is one of the major contributors to the increase in atmospheric CO2 concentrations. An appropriate way for simultaneous restoration of SOM stocks and deposition of sequestered carbon is the straw application into the soil. The aim of the study was to evaluate the effect of straw application on the quantitative indicators of different groups of microorganisms in a soddy-podzolic soil (Umbric Retisol) in a long-term field experiment. Straw application increased microbial biomass carbon (Cmic) by 1.25-2 times, with the greatest increase in microbial biomass in trials without mineral fertilizer. Basal respiration and metabolic quotient (qCO(2)) increased in the sequence: control < NPK < NPK + straw < straw. Application of straw increased the gene copy number of fungi and bacteria up to 2 times and archaea up to 1.5 times. Application of mineral fertilizers without straw reduced qCO(2), fungi biomass, and archaeal gene copy number by 1.5-3.0 times. The fungi/bacteria ratio varied from 4 to 15 as determined by the fluorescent microscopy and from 0.17 to 0.33 as determined by quantitative PCR. The lowest values of fungi/bacteria ratios were found in soils with the application of mineral fertilizers, and the highest ones, in soils with the straw application. Thus, the regular application of fresh organic matter of straw is an important technological procedure to increase the soil microbiological activity and mitigate the negative impact of mineral fertilizers on soil microbiota.