Home – Home – Jornals – Contemporary Problems of Ecology 2025 number 2

The aim of this work was to study the bioproductivity, C-biomass and elemental composition of humic acids as a single ecosystem of dry-steppe soils. The objects of the study were virgin chestnut soils of the southern steppes of Western Transbaikalia. It was revealed that chestnut soils are formed under dry-steppe plant associations with sparse and low-growing grass, with a poor species composition. The net primary production in chestnut soils of the study region is 4.80 ± 3.48 kg/m² year, where the underground mass exceeds the aboveground mass by 9 times. Plants of more continental steppes, with a greater moisture deficit, direct a larger proportion of photosynthetates (up to 90 %) to the root mass compared to plants of the western steppes. The ratio of BNP to ANP is 1 : 9 and can reach 1 : 25. The participation of C-biomass of microorganisms in the total reserve of organic carbon of chestnut soils is up to 2.5 % of Corg. The dynamics of accumulation of C-biomass is limited by soil moisture and the reserve of energy resources. The elemental composition of HA of cold, chestnut soils is characterized by a low carbon content; relatively high content of nitrogen and hydrogen. The molecule of HA of chestnut soils has a weakly condensed aromatic nature, the aliphatic part predominates in it. The consequence of the weakened condensation reaction is an insignificant level of the degree of benzenoidity. ¹³C-NMR spectroscopy showed that the humic substances of chestnut soils are characterized by a reduced content of aromatic components.