Assessment of Dissolved Organic Carbon and Nitrogen Fluxes in Abandoned Agricultural Lands of the Vologda Oblast

The pH, concentrations, and fluxes of dissolved organic carbon and total dissolved nitrogen are assessed and compared in three types of biogeocenoses—bluegrass birch forest, tall herb alder–willow birch forest, and forb–bluegrass meadow—situated in an abandoned arable land in the Cherepovets raion (Vologda oblast, Russia) with postagrogenic residual-carbonate soddy-podzolic soil (Endocalcaric Albic Retisol). The input of dissolved organic carbon in forest biogeocenoses is 4.2-fold higher as compared with meadow biogeocenosis, while its removal is 3.6-fold lower in forest ecosystems. As for the influx of total dissolved nitrogen, it does not differ in the studied biogeocenoses, whereas its leaching in meadow biogeocenoses is 5.4-fold higher as compared with forest ones. The carbon accumulation in the soil profile of forest biogeocenoses averages 48.5 kg C/(ha year) versus meadow biogeocenoses with an almost neutral balance between the input with precipitation and leaching with soil waters, amounting to –1.7 kg C/(ha year). The nitrogen accumulation rate in forest ecosystems amounts to 1.5–1.7 kg N/(ha year) versus only 1.0 kg N/(ha year) in meadow biogeocenosis. As is shown, the development of wood species on the fallow considerably influences the fluxes of dissolved organic carbon and nitrogen both when migrating through the tree canopy and the soil profile.