Olga Igorevna Filippova

The carbon reserves in main components of Moscow region coniferous-broadleaf forest were studied: various fractions of the tree stand, dead wood, mortmass, litter, living ground cover and mineral profile of the soil. To assess the potential intensity of organic matter decomposition, a number of indicators of the functioning of the microbial biomass were determined. An assessment is given of the carbon reserves and their shares in the ecosystem components that differ in the rate of renewal and potential capacity for carbon sequestration, as well as the degree of their spatial variation. The total carbon pool of the studied forest ecosystem is 18.7+0.8 kg·m–2, with almost 90% of the total stock concentrated in the perennial parts of the tree stand, dead wood, mortmass and mineral profile of the soil. These most stable pools are characterized by the least spatial variation within the biogeocenosis. The carbon reserves of the assimilating part of the grass layer and tree leaves are only 0.02 and 0.08 kg·m–2, respectively. The carbon reserves of litter are quite low - 0.21 ± 0.04 kg·m–2, which does not exceed 2% of the total carbon reserves of the ecosystem. The data obtained indicate that even secondary subclimax forest ecosystems are a significant absorber of atmospheric carbon, mainly due to the mass of the tree stand and soil organic matter.

The study aimed to perform a systematic study and meta-analysis of national and foreign data (687 data points in total) on the effect of humic preparations (HPs) on crop yields. Specific objectives included evaluating the efficiency range of HPs (yield increase as a percentage of the control) accounting for statistical uncertainty estimated via absolute median deviation, and assessing the influence of HPs characteristics, crop types, and soil properties on this metric. HPs efficiency varied from –59% to +540% (mean 18%) and followed a non-normal distribution. The median efficiency was 12 %, with lower and upper quartiles at 5% and 21%, respectively, and uncertainty of 99 %. Kruskal–Wallis test revealed that soil granulometric composition and HPs enrichment with trace elements did not significantly affect efficiency of HPs. Key influencing factors included: cation salts of humate in HPs (Na salts were the least effective); HPs application method (combined soil and foliar application was most effective); soil acidity and humus content (higher efficiency at pH > 6.6 and humus content < 1%). Plants in the aster family showed the greatest responsiveness to HPs, while legumes and nightshades exhibited significantly lower efficiency. Under nitrogen deficiency, HPs efficiency rose to 22%, and most studies reported increased nitrogen and/or protein content in crop products. These findings suggest that HPs primarily enhance field yields by improving plant nitrogen assimilation. The results indicate that promising future research should evaluate HPs effectiveness against reduced nitrogen fertilizer rates. Given rising fertilizer costs, even modest effects could prove economically viable. Further field studies should optimize HPs use conditions and methods, prioritizing identification of factors driving efficiency uncertainty — preliminarily, application method and soil conditions (pH, humus content, and available nitrogen).