Nowadays under the conditions of a heavy anthropogenic load on nature, preservation of the biological diversity of natural landscapes in their pristine state is an urgent task for mankind. One of such landscapes in Kherson Region of Ukraine is a wildlife reserve of national importance Sagi Wildlife Reserve. It has an area of 500 hectares and is a part of the giant sand massif called Lower Dnieper Sands. The total area of the massif is 2.085 km2, so it is often called the largest desert in Europe. The forest stands planted in the 20th century have stopped moving the sands from the massif onto the settlements and agricultural land. However, the question of predicting the behavior of sandy soils in the future and determining the role of various types of vegetation in preventing the processes of deflation of these soils and in stabilizing their surface remains relevant.
Materials and Methods
The aim of the study was to assess the soil and microclimatic conditions in the Lower Dnieper Sands massif using the example of the Sagi Wildlife Reserve and to estimate their suitability for vegetation growth. Sandy soils occupy most of the reserve area, namely 386.8 ha. The forested area is 117.6 hectares, at that, 86.6 hectares are covered by pine, 24.8 hectares by birch and 4.7 hectares are occupied by alder. Planted pine stands surround the sand massif restraining its expansion, but how its inside sands are protected from deflation and movement in ridge form depends totally on the grassy vegetation ability to counteract these processes.
The analysis of meteorological information by literary sources and Internet resources, field studies by means of the generally accepted methods of soil physical research were used in the study.
The climatic and soil conditions of the Sagi Wildlife Reserve have been studied. The climate structure by composition of its weather conditions is determined, a new method for constructing the resulting vector of transfer rose is presented. The statistical parameters of the trunk diameters of Dnieper birch (Betula borysthenica Klokov) are calculated. The structure of the soil profile was studied at three characteristic points of the mesorelief of the area, namely at the top of the dune, at its foot and in the birch bunch located in in one of the closed depressions of deflationary origin. The hardness of the soil was determined. The study showed that the soil becomes harder with the depth growing. Thus, at a depth of 14 cm the soil’s hardness makes 37 g·cm-2 which is a sign of severe conditions for seed germination and root penetration into the soil. The bulk density of the soil reaches 1.7 g·cm-3. As for the particle size distribution, the soil is characterized by medium-size particles, and it is homogeneous. The filtration coefficient at the studied points varied from 2.5 to 11.3 mm per min. It was established that even sparse dry grassy vegetation with dangerous gusts of wind up to 13.2 m per second, measured at a height of 2 m, reduces the wind speed at a height of 8 cm to 2.3 m per second.
The research results point at severe conditions for vegetation on the Lower Dnieper Sands due to a low fertility potential of sandy soils, their high density, hardness and low ability to retain precipitation moisture. Due to a low adhesive capacity of sandy soils, they are potentially extremely vulnerable to wind. However, continuous grass cover can reduce wind speed above the soil surface to the safe level. Therefore, to protect sandy lands from deflation, it is very important to protect vegetation cover and not let it be ruined by motor transport and domestic or wild animals.
6 Figs., 10 Tables, 25 Refs.
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