Vegetation restoration and organic matter accumulation on former agricultural lands in the boreal zone of Russia

This work investigates the influence of vegetation succession processes on the soil changes of former arable lands. It was noted that on post-agricultural soils, accumulation of organic matter in the soil differs, depending on the state of the land plot. The analysis shows that influence of vegetation on the accumulation of organic matter in the former arable horizon has a distinctly linear nature. The dominant species are mesotrophic and mesophyte plants, requiring little more than soils with mineral nutrients and sufficient humidity. The amount of organic matter accumulated in the upper horizon of the soil is greater than that of the underlying horizon. The content of organic matter in the soil horizons of the studied area is characterized by a distinct decreasing pattern in the direction from the forest edge to the field edge. Overall, it can be noted that farther away from the forest edge, the soils change from moderately acidic to slightly acidic. At this stage, depending on the succession state of the post-agricultural soil plot, the amount of organic matter in it is determined either by the species forming the soil cover and (or), to a greater extent, by tree and shrub vegetation. The optimum of the organic matter accumulation shifts to the zone with a large share of tree species.