Condition of the soil complex under the mature stands of pine and spruce on post-agrogenic lands of the south-west of the Leningrad Region

Abstract

Land that has been taken out of agricultural use, during the restoration of plant communities, contributes to the formation of tree stands, depending on the characteristics of its origin. New knowledge about the formation of plant communities on such lands can allow to predict the processes taking place in these ecosystems and to make optimal decisions for further actions. Sample plots were laid in the former old-fallow lands in the Leningrad region in contrasting landscapes of Luzhsko-Oredezhsky (Gatchinsky district) and Izhora (Volosovsky district). These fallows are currently covered with coniferous stands of mature age with different proportions of pine (Pinus sylvestris L.) and spruce (Picea abies [L.] Karst). We carried out taxation and determined the agrochemical indicators of the soil profile horizons – the content of organic substance, acidity, mobile forms of phosphorus and potassium. Formed mature stands of pine and spruce on old arable land differ in their taxation characteristics, which is associated with landscape features and the soil conditions of their growth. In general, the productivity of these stands is higher than that of similar forest soils in the study region. Signs of soil cultivation under the forest remain even after a long period of time and the level of soil productivity is also higher than under stands of forest land. The agrochemical condition of the former arable soils showed that under stands with different shares of pine and spruce depending on the soil differences in the two contrasting landscapes, they are not restored to the native state of forest soils.