Soil diversity in the southern part of Aleksandrino Park (Saint Petersburg) and the impact of plantations on soil fertility

Abstract

Aleksandrino Park is a unique research object. The park’s territory contains soils that are diverse in their morphological characteristics. Soil formation processes are influenced by factors such as climate, relief, flora and fauna, parent material, time, and anthropogenic impact. This study focused on the influence of tree species on soil fertility. The research object was the southern part of Aleksandrino Park. In 2021, ten plots with different plantation compositions were selected. In 2022, seven plots with pure plantations (larch, pine, and oak) were studied. Soil profiles were established on all plots, morphological descriptions were carried out, and laboratory analyses were performed to assess soil fertility. Morphological descriptions in the pure plantations in 2021 revealed three naturally disturbed soils and seven podzolic soils. In 2022, morphological descriptions of the pure plantations identified two naturally disturbed soils and five podzolic soils. Based on the results of agrochemical studies, soil fertility was assessed. The findings indicate that plantation composition affects the following: humus content (well supplied in general); exchangeable acidity (in pure plantations (larch, pine, oak), acidity is slightly lower and closer to neutral); nitrogen content (high nitrogen availability in plots with pure larch plantations). Available potassium is unaffected by plantation composition, with low potassium availability across all plots.