The influence of different types of land use on the stocks and distribution dynamics of organic carbon (С), total nitrogen (N), available potassium (К) and phosphorus (Р) in a meter layer of soils of different genesis in the middle taiga subzone of Karelia (Eastern Fennoscandia) were studied in 2019–2022. Arable land, hayfields, 15–20 and 65–75 years-old natural reforestation forests on former agricultural lands, as well as control forests for 100 years or more were studied on Retisols, Podzols, Umbrisols, and Cambisols. The stocks and distribution of biogenic elements are influenced by both the type of land use and the genesis of the soil. Changes are characteristic not only of the upper horizons but also of deeper soil layers. Agricultural use results in statistically significant accumulation of stocks by biogenic elements. On average, arable lands accumulate 193,8 t/ha of С, 16,8 t/ha of N, 1,96 t/ha of available potassium and 2,54 t/ha of available phosphorus. The stocks of biogenic elements tend to decrease in forest ecosystems. Soils of mature forests contain on average 83,4 t/ha of С, 6,0 t/ha of N, 0,24 t/ha of available potassium and 0,65 t/ha of available phosphorus. Carbon mainly accumulates in the upper part of the profile in the forest litter and decreases sharply with depth in the forests. Nitrogen accumulation is also observed in the upper soil layer, with its maximum occurring in arable land, hayfields and young forests. Carbon and nitrogen are typically distributed uniformly across the depth of arable land and hayfields. К and Р mostly have an accumulative-eluvali-illuvial and undifferentiated type of distribution in forest ecosystems, and they mainly accumulate in the middle part of the profile in agricultural land uses.
I. A. Dubrovina (Wed,) studied this question.