Soil modification in a chronosequence of postagricultural ecosystems of the intrazonal lithogenic matrix (Arkhangelsk region, Russia)

Processes of soil self-restoration and soil modification in the chronosequence of postagricultural ecosystems located within the intrazonal (floodplain) soils of boreal forests were studied. Successional changes in ecological features of the floodplain meadow soil properties in the postagricultural period were considered. We used arable land plots (22 model fields) in the Northern Dvina River delta (Primorsky District, Arkhangelsk region, Northwestern Russia) that have been removed from agricultural practice for the past 50 years and are currently at the self-overgrowing stage. Primary/secondary floodplain meadows with natural floodplain soils were used as reference plots. Changes in soil profiles and chemical properties in an oldarable horizon were observed during the restoration of abandoned fields. Floodplain soils of the Northern Dvina River basin occupied 4.8% of the area. These soils were characterized by high fertility and were actively used in agricultural production in the past. Postagricultural ecosystems of the Northern Dvina River floodplain tended to form natural waterlogged soils to varying extents. Ecosystems were characterized by a short period of soil restoration. The soil restoration process was slower than the vegetation cover restoration process. Soil fertility of the arable horizon persisted for 20 years. A cost-effective return of floodplain meadow lands to agricultural production is feasible over a period of 40 years. Then, soils return to natural floodplain soils, whereby they become waterlogged and lose their fertility.