Changes in the content of bioavailable heavy metal compounds in the soils of Crimean mountain plateaus after afforestation

Abstract

As a result of afforestation of the Crimean mountain plateaus in the middle of the last century, about 3 thousand hectares of forest plantations were created on their surface. Studies on the influence of these plantations on the properties of mountain-meadow soils (Phaeozems) have shown that under the forest vegetation there were an enlargement of structural aggregates, a decrease in humus content, and an increase in acidity compared to soils under meadow vegetation, which could also affect other soil properties, including the mobility of some metals. The purpose of this research is a comparative analysis of the content of mobile forms of Pb, Mn, Cu and Zn (1 M ammonium acetate) in the soils under mountain meadows, natural beech forest and artificial forest plantations. According to the results obtained, mobile Pb, Mn, and Cu were accumulated in forested mountainmeadow soils relative to adjacent areas of mountain meadows. So, in the soil layer of 0-10 cm under stands of pine (Pinus kochiana Klotzsch ex K. Koch), the average Pb content in comparison with soil under meadow vegetation was more than 1.6 times, Mn -1.2 times, Cu -in 1.2 times. Under the birch (Betula pendula Roth), Pb was 2.5 times more, Mn was 1.5 times more, and Cu was 1.2 times more. Under larch (Larix sibirica Ledeb), Pb was 2.2 times higher, Mn was 2.4 times higher, and Cu was 1.5 times higher. In comparison with the meadow, the soil under maple (Acer pseudoplatanus L.) contained 1.9 times more Pb, 1.1 -Mn, and 1.3 -Cu. Differences between forested and meadow soils in the content of these elements in most cases were reliable, except for the content of Zn, signs of accumulation of which under artificial plantings were not revealed. The content of Pb, Mn and Cu in the brown forest soil (Luvisols) under the beech (Fagus orientalis Lipsky) corresponded to their concentration under the larch, and Zn was significantly higher compared to the soil under all tree species. The main reason for increasing the mobility of a number of elements under tree stands is their transformation from low mobility forms under the influence of increased acidity of forested soils. Leaf litter due to the low content or complete absence of trace elements in its composition cannot be a source of their accumulation in the upper layer of the soil.

The shifts in the structure of the prokaryotic community of mountain-grassland soil under the influence of artificial larch plantations

“…The climate of the plateau according to the Ai-Petri weather station (1,180 m) is characterized by an average annual precipitation of 1,052 mm, an average annual temperature of 5.7˚C, an average temperature of -3.8˚C in February, and 15.5˚C in July. Most of the precipitation (62%) falls during the cold season from November to March [7].…”