Home – Home – Jornals – Siberian Journal of Forest Science 2025 number 5

The effect of mycocompost (the bioadditive) - pine sawdust partially destructured by a wood-destroying fungus culture - on the forest grey soil microbiocoenosis (Krasnoyarsk forest-steppe) was studied. Mycocompost variant was compared with the two ones: soil without bioadditives (control) and soil with addition of intact sawdust. In the trial areas (1 m²), a layer of turf was removed, bioadditives were applied in the amount of 1 % by weight to the top soil layer (10 cm), then the cut turf was returned to its place. During the first year an increase of the total number of soil microorganisms by 5-10 times was observed in all variants of the experiment including the control that was mainly related to the products of degradation of dead turf. Microbial processing of the both sawdust and mycocompost began in the second year of the experiment and was accompanied by a temporary decrease in soil pH, changes in the structure of soil microbocoenosis, a rise in the proportion of fungi and oligotrophic microorganisms, as well increase of availably nitrogen deficiency. The analysis of the data on soil microorganism number, structure of microbocoenosis, microbial respiration and biomass, mineralization velocity of organic matter, enzymatic activity, etc. showed that during two years in the variants with mycocompost and intact sawdust microbial utilization of bioadditives occurred gradually and did not cause imbalance of biological processes in grey forest soil. The mycocompost variant exceeded the control and sawdust ones in terms of the total number of soil microorganisms and biomass on average 2-3 times, did not cause stable soil acidification and provided better preservation of the introduced culture of Trichoderma harzianum Rifai. In combination with additional nitrogen supplementation, mycocompost can be used as a biofertilizer for poor forest soils.