Spatial and Temporal Dynamics of Carbon Dioxide Emission from Al-Fe-Humus Sandy Soils in the Forest-Steppe Zone

The study presents data on spatial and temporal variability in the carbon dioxide efflux from Al–Fe-humus sandy soils of the forest-steppe zone in the central chernozemic region of Russia (Kursk oblast). The CO₂ emission was estimated in situ using the closed chamber method. The factors of daily and seasonal variability of the emission for Albic Podzols (Arenic) and Albic Podzols (Arenic, Ochric) were under consideration. The transformation of the basic biological, morphological, and physicochemical properties of Albic Podzols (Arenic) under successional change of pine forest plantations to climax oak forests was analyzed. The research revealed that daily and seasonal variations in the CO₂ efflux from Albic Podzols (Arenic, Ochric) were, respectively, 1.8 and 2.1 times greater than those from Albic Podzols (Arenic). Soil temperature determined the seasonal variability in the rate of CO₂ efflux from Albic Podzols (Arenic) and Albic Podzols (Arenic, Ochric), whereas the soil moisture determined the spatial variability in the rate of CO₂ emission from these soils. Temporal changes in soil moisture and temperature had an ambiguous effect on the daily dynamics of CO₂ emission from Al–Fe-humus sandy soils in the forest-steppe zone. Natural succession in pine forests can significantly increase the carbon sequestration potential of soils. Humus stocks in Albic Podzols (Arenic) relative to Albic Podzols (Arenic, Ochric) in Kursk increased from 17.2 to 38.4–56.2 t/ha. Carbon sequestration in the biomass of deciduous forest increased by 50% relative to that in the biomass of pine forest.