Igor Alexandrovich Ilyichev

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.

Abstract The RothC-26.3 model was used to reproduce the 62-year dynamics of soil organic carbon (SOC) in Retisols within a long-term field experiment conducted by the Federal State Budget Research Institution «Federal Research Center for Bast Fiber Crops». Simulation modeling was employed to assess the potential for increasing SOC stocks by 2090 through modifications in agrotechnological practices under two climate scenarios and two adaptive economic scenarios. The feasibility of utilizing alternative fertilizer sources and minimal tillage as supplementary approaches for SOC accumulation was examined. The results indicate that under existing management practices and future climate conditions, SOC stocks in the topsoil (0–20 cm) of the studied soils could increase by up to 34% of the initial content by 2090. Furthermore, the implementation of carbon-saving technologies—including adjustments to crop rotation structure, as well as the rates and sources of organic fertilizer application—could enhance SOC accumulation, leading to a potential increase of up to 82% by 2090. Under different climate scenarios, the maximum sequestration rate was projected to reach up to 11‰ per year. Among the alternative organic fertilizers evaluated, the application of composts and peat mixtures yielded the most favorable outcomes, facilitating an additional SOC accumulation of up to 10.6 tha–1 compared to the use of cattle manure. In contrast, the use of green-manure fallows and minimal tillage cannot be considered an optimal strategy for SOC sequestration, as these practices resulted in lower accumulation relative to cattle manure application. It was demonstrated that the studied soils possess considerable potential for organic carbon accumulation while remaining under agricultural cultivation.