Elena Aleksandrovna Belyaeva

The main components of the CO2 balance - emission from the surface, removal with lysimetric runoff, and dynamics of reserves in a 1.5 m soil layer, taking into account interphase equilibria, were quantitatively assessed in a 2-year soil-lysimetric experiment. A significant (up to 20-90%) contribution of lysimetric runoff to the total gas exchange in cold weather (autumn-winter) against the background of a small (0.3-3.7%) share during the growing season (spring-summer) is shown. Due to the unsteadiness and inertia of gas accumulation / unloading processes inside the soil, emission from the surface does not adequately reflect the gross CO2 production by the soil volume, underestimating in the spring-summer period and overestimating in autumn. The obtained 2-year correlation between emission and gross-production indicates the possibility of a 1.3-1.4-fold underestimation of the dissimilation component of the carbon cycle in the traditional emission assessment of soil respiration.

The high water retention and water capacity functions of detritus determine its potential hydrological significance in the formation of the water regime of soils and phytoproductivity of forest landscapes. Using computer modeling of water exchange in the “soil-plant-atmosphere” HYDRUS-1D system, we preliminary studied the hydrological func- tion of detritus for water retention of precipitation and root water consumption at different amounts and variants of the arrangement of detritus layers in the soil profile. The soil structures designed on the basis of this information for sustainable afforestation with increased carbon sequestration demonstrated in field experiments with water balance monitoring high efficiency in optimizing the water retention capacity of the soil and roots water consumption of the test crop (Glauca spruce) with a 2-3-fold reduction in unproductive water losses and a 1.5–2-fold increase in the current plant growth relative to untreated control. The physical mechanism of the detritus hydrological function is the formation of capillary barriers blocking evaporation and capillary resorption of soil water due to due to surface accumulation (forest litter) or placement in layers inside the soil (peat layers in constructosems).