The microbial communities’ development on the surface of crop residues
M.A. Alyoshin, T.V. Poludova, A.I. Botin, A.A. Zavalin
Section: Agroecology
As part of a laboratory model experiment, microbial communities were found on the surface of grain straw. As polymicrobial biofilms they formed during the initial period of the straw decomposition in sod-podzolic medium loamy soil (Eutric Albic Retisols (Abruptic, Loamic, Cutanic)). The metabolic activity of microorganisms on the surface of pea straw (Pisum sativum L.) was higher than on wheat straw (Triticum aestivum L.). The following dynamics was recorded. On day 1, an exponential growth phase was determined, within which an increase in metabolic activity and a significant increase in bacterial biomass were observed. From 2nd to 15th day there was the phase of stationary growth. From day 15, the phase of microorganism growth was replaced by the phase of death. A comparative analysis of the metabolic activity of microorganism dynamics on the surface of sterilized by autoclaving and non-sterile straw didn’t reveal the effect of the initial saprotrophic pool in the organization of microbial community on the surface of straw during its further decomposition. In scrapings from straw incubated in the soil for 5 or more days, a significant predominance of microbes on pea straw was observed. The microbiota was represented by small gram-negative and gram-positive rods, bacillus spores and micromycetes were also present. When straw is introduced into the soil, the gradient of the microbiome density distribution is determined. The study showed that bacteria immobilized on straw have increased viability, higher metabolic activity and contribute to more efficient decomposition of plant substrate. Adding straw to the upper soil layers helps restore and strengthen the soil microbiome.
ISSN 1995-4301
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