Nitrogen Nutrition of Plants in an Alpine Lichen Heath under the Conditions of Soil Enrichment with Biogenic Elements

The results of a long-term experiment on the enrichment of the soil (Umbric Leptosol) of an alpine lichen heath with biogenic elements have shown that calcium addition and reduction of soil acidity do not change the nitrogen regime of the soil and patterns of nitrogen nutrition of plants. The increase in phosphorus availability contributes to the mobilization of soil organic nitrogen and shifts in the role of mycorrhiza in the nitrogen nutrition of plants, which determines their heavier isotopic nitrogen composition. At the same time, this reduces the intensity of nitrogen fixation by a nitrogen-fixing legume species, Oxytropis kubanensis. The increase in the availability of nitrogen leads to its active uptake by all studied plant species except Oxytropis kubanensis, as well as to the heavier isotopic nitrogen composition of plants. However, changes in the nitrogen status differ between plant species.