The soil is called surface layers of mellow rocks changed under the influence of vegetable and animal organisms. The most important soil’s property, distinguishing it from the rocks, is fertility - the ability to create the necessary conditions for plant life, provide them with moisture and nutrients during the entire period of their growth and development. The level of the soil fertility depends on its composition and properties, in particular, the number and quality of the contained organic substances, reaction (acidity or alkalinity), the ability to retain moisture, the air mode and heat exchange system.
Factors of soil formation
The formation of rocks and soils is influenced by natural conditions. The founder of the doctrine of the soil (soil science), Russian scientist V. V. Dokuchaev identified the following soil-forming factors:
• soil-forming (maternal) rock
• biologic plant and animal world
• age of a territory or ecosystem
The rock that influence on the process of soil formation is called the mineral soil base. As a result of soil-forming process the rock changes, enriches, or, conversely, exhausted by different components, acquires the construction and the structure peculiar to the soil. Climate influence may become apparent directly by impact of precipitation, atmosphere, and radiant energy, or indirectly through the vegetation and the animal world. In different climatic conditions the composition and productivity of vegetation vary greatly. Therefore, their impact on soil-forming rock will also be different.
The main factor of soil formation is the world of flora and fauna. The first stage of soil formation process is the colonization of rocks by plants and animals. Later under the influence of biological factor rock is converted to soil. The most significant role in the conversion process belongs to high plants. In tundra zone soil formation occurs with considerable participation of mosses, especially lichens. Plants are involved in the destruction of rocks, circulation of mineral elements that enrich the soil with organic matter. They have a huge impact on the air system of the soil, heat and moisture.
Soil-forming factors and their distribution are highly dependent on the territory relief. And at the same time it has a strong influence exposure and steepness of slopes, the height of the terrain affecting the heating of the soil, the contact of the surface with precipitation, their distribution. Besides in many respects they influence the plants.
Soil formation takes a long time, so the territory age significantly affects the ground cover. Especially it deals with the areas affected by the previous processes of glaciation. Among them the territory of the Kola Peninsula. Its different parts were eliminated from the retreating glacier at different times, thus, the soil age can also be varied.
All these factors of soil formation are of equalimportance. It means that the soil can't be formed without any of them. The soil variety is influenced by the factors that individually function unevenly and their result have a different intensity.
On the territory of Murmansk region there are two dominating soil types - podzol and peat. Moisture conditions have an impact on the nature of the vegetation and soil forming rocks. There scientists distinguish different types of soils from dry «dwarf» podsols to peaty-podzolic and boggy peat soils.
On the territory of the Khibiny massif soil zoning is vertical. The surface of the plateau is covered with primitive soil covered by the lichen tundra. The upper slopes are characterized by the formation of illuvial-humus soils (mountain tundra). In the shrubs area you can meet podzolic types. Such soil types as mountain podzolic illuvial-humus, «dwarf» podzols and sub (the territory of crooked birches) represent the lower part with the forest area.
Extensive territory near Kirovsk is polluted by the toxic elements and heavy metals. They are in the soil in large quantities, and their concentration indexes exceed the permissible rates. As a result, in order to obtain environmental safety in this territory it is possible only by revegetation.
Each soil is characterized by the presence of distinct layers (horizons) replaced each other from the surface to the soil forming rock. A set of horizons peculiar to this soil makes its profile.
In the Khibiny scientists distinguish forest, subalpine and Alpine soil-vegetation zones. Forest soils are called «dwarf» podzols due to their thickness, not exceeded 40 centimeters. Also the vast territory of this zone is occupied by humus-illuvial podzol soils. Subalpine zone is presented by the peaty humus-illuvial soils. In the Alpine zone the main soil type is the mountain-tundra soils. In the upper parts of the massif it is observed the weathering of nepheline syenites, in the local waters of rivers and lakes, and glaciers - the sediment process. All of these formations influence on the formation of soil rocks.