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The method of component integration was tested in the course of studies in typical biogeocenoses of the north of Western Siberia. This method as applied for separate horizons made it possible not only to estimate the contribution of different sources to the total efflux of CO2 from soils but also to evaluate the participation of horizons in soil respiration. Root respiration contributed to about 14 ± 3% of the CO2 efflux from the permafrost-affected peat soil (Hemic Cryic Histosol) and to about 29 ± 6% of the CO2 efflux from the tonguing podzol (Glossic Albic Rustic Podzol (Arenic)). Histosol was characterized by a higher storage of total (organic and inorganic) carbon (26 kg C/m2), extractable carbon (Cextr) (32 g C/m2), and microbial carbon (Cmic) (43 g C/m2). Its upper horizon (TO) contained about 50% of the total soil storage of Cmic and 100% of the total storage of roots (up to 300 g/m2). It had the maximum activity of microbiota and contributed to more than 70% of the total efflux of CO2 from the active layer (on average, 35 cm in thickness) of Cryic Histosol. Podzol was characterized by the low storage of total carbon (6 kg C/m2), considerable storage of Cmic (38 g C/m2), and much higher microbial activity. This circumstance, together with a tenfold higher storage of the roots (up to 3000 g C/m2) and favorable temperature regime specified high values of the gross production of CO2 and its emission from the Podzol surface exceeding the corresponding values for the Cryic Histosol by three–five times. The mineral profile of Podzol contributed to about 20% of the total efflux of CO2 from this soil (on average, about 38 cm in thickness). [ABSTRACT FROM AUTHOR]

Statistical analysis of a vast body of data collected during five field seasons (2011-2015) was performed to characterize the biological activity of soils in the northern taiga ecosystems of Western Siberia. Automorphic forest soils, hydromorphic (oligotrophic bog) soils, and semihydromorphic (flat-topped and large peat mounds) soils were characterized. Statistically significant differences of average levels of CO2 emission from the soils were identified at the ecosystem level. The CO2 emission from podzols of automorphic forest ecosystems at the peak of the growing season (205 ± 30 to 410 ± 40 mg CO2/(m2 h)) was significantly higher than the emission from semihydromorphic soils of peat mounds (70 ± 20 to 116 ± 10 mg CO2/(m2 h)). The presence and depth of permafrost was a significant factor that affected ecosystem diversity and biological activity of northern taiga soils. Statistically significant differences in the total, labile, and microbial carbon pools were observed for the studied soils. Labile and microbial carbon pools in the organic layer (10 cm) of forest podzols amounted to 0.19 and 0.66 t/ha, respectively; those in the organic layer (40 cm) of peat cryozems of flat-topped peat mounds reached 1.24 and 3.20 t/ha, and those in the oligotrophic peat soils (50 cm) of large peat mounds were 2.76 and 1.35 t/ha, respectively. The portion of microbial carbon in the total carbon pool (Cmicr/Ctot, %) varied significantly; according to the values of this index, the soils were arranged into the following sequence: oligotrophic peat soil < peat cryozem < podzol. [ABSTRACT FROM AUTHOR]

In the discontinuous cryolithozone in the north of Western Siberia in forest and tundra biogeocoenoses, two field methods for individual determination of root and microbial soil respiration were tested: plant shading and root exclusion (comparison of the plots with vegetation and without it). The proportion of of root respiration in the total soil respiration in the forest biogeocoenosis was 7-50%; in the tundra, 10-50%. The plant shading method has been physiologically substantiated, is the least time-consuming, and the least damaging to soil function (moisture and temperature do not change). The proposed modification of the method (root exclusion on natural objects) demonstrated a satisfactory result, but it is not universal due to the specifics of objects. [ABSTRACT FROM AUTHOR]