Презентация: Почвы Ленинградской области
презентация к уроку на тему

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АНГЛО-РУССКАЯ ПРЕЗЕНТАЦИЯ НА ТЕМУ: ВИДЫ ПОЧВ ЛЕНИНГРАДСКОЙ ОБЛАСТИ

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Most of the land surface is covered with soil. The soil is made up of fragments of rocks humus remains of plants and animals. Soil is the product of the functioning of terrestrial plant formations, a necessary condition for the existence of all living things. It covers a land everywhere except deserts, polar regions, steep slopes and landscapes created by man. Although the soil is composed of decaying matter, it is not dead, it changes all the time. A tiny piece of ground full of water, air, there are billions of bacteria, microscopic algae, fungi, which make the soil suitable for living in her worms, insects and other animals, as well as for the growth and development of plant roots layer of fragments of rocks called regolith slowly turns into the soil under the influence of substances that are formed as a result of the processes of decay of the remains of plants and animals. This can be seen on the soil horizons. An overview of the soil

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HUMUS -layer decaying organic matter. Humus is necessary to maintain a balance of minerals and other nutrients necessary for plant growth. UPPER Layer- A horizon - the top layer of soil in which the plant roots are located and live organisms. Rich in minerals and organic substances. PODPOCHVA- horizon B consists essentially of rock fragments. He is poor in humus and rich in inorganic substances that enter the water here. HORIZON C consists of fragments of rock and low organic matter. HORIZON D (Bedrock) - the lowermost horizon of the soil, which forms the fundamental underlying rock, which split off from the fragments falling into the higher layers.

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SOIL VALUE The value of the soil: Keeping moisture and nutrients. Reliable fixation of plant roots. habitat for many organisms. Sanitary and protective functions: many pathogenic bacteria in the soil die quickly, and contaminants, lingering in the ground, do not fall into the ground and surface water. Resistant to decomposition of soil organic matter is an accumulator of solar energy. Soil and vegetation cover keeps the land surface from damage and erosion, regulate the water regime and the composition of the atmosphere. The doctrine of the soil, as a special body of nature, scientific development received only a little over a century ago in the writings of Russian scientist Vasily Dokuchaev. Soil, according to Dokuchaev, - a "mirror of nature", reflects the combined effect of climate, plant and animal organisms, properties of the surface of rocks, a relief, as well as the duration of the action. Interaction of the factors listed above soil determines the occurrence in nature of different types of soils.

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Leningrad Region is located in the zone of middle and southern taiga. On the territory adjacent to the Gulf of Finland, diverse soil factors, which leads to the heterogeneity of soil cover. Native pine and particularly spruce forests are preserved in some places in the north-west and east of the region, but, basically, they are of little value and unproductive substituted derivatives of small-leaved forests and bush (birch, aspen, alder). In the Ordovician plateau in the past was dominated by broad-leaved coniferous forests with oak, maple and linden ,, meadows and bushes. In waterlogged areas dominated by sedges and marsh grasses, mosses possible settlement.

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Vegetation in the Leningrad region is quite diverse. The region is located in the taiga zone, namely, in its central and southern subzones. It marked the transition from the coniferous forests to the south of the mixed area. Forests cover 55.5% of the territory. Forest resources are severely depleted. In the forests of the region are growing herbs and berries: lily of the valley, bearberry, blueberry, lingonberry, cranberry, raspberry, rosemary, juniper, immortelle sandy, cinquefoil erect. Areas adjacent to the city of St. Petersburg, under agriculture (arable land, grassland, shrubs).

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The main soil type in the area are podzolic, poor in humus and characterized by considerable acidity. Thus on loam, in low areas with increased moisture accumulation mainly in spruce forests formed of strongly potent upper soil layer. In coniferous forests of the parent rocks containing little calcium, plant litter accumulated on the soil surface and forms a so-called litter. Under the bedding sometimes may form a low-power organic-mineral soil layer (horizon), dyed newly formed humic substances in gray tones. In the process of decomposition of litter, poor mineral substances, a large amount of organic acids, which are washed by precipitation in the deeper mineral horizons.

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Organic acids accelerate the destruction of parent rock minerals. Only quartz is resistant to organic acids and accumulates in the upper soil layers. Thus is formed a characteristic light colored, almost white, vymyvnoy (eluvial) proper podzolic horizon. Consumption of nutrients and, if they are not absorbed by plants, it can be washed in, or downstream beyond the horizons of soil profiles. Illuvial horizon (illuvial) usually painted brown tone. Illuvial horizon is gradually transformed into the parent rocks. Power horizons depends on the intensity of the podzol-forming process that gives rise to weakly, medium and strongly pochvy.V higher ground less favorable to the accumulation of moisture, formed srednepodzolistye soil. On sands and sandy loams, poor moisture retention in the pine forests meet podzolic soil .

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If you change the conditions of soil formation (change of vegetation) intensity podzol process may vary. When herbaceous vegetation on the podzolic process as applied to turf, resulting in the formation of sod-podzolic soils with their characteristic pronounced in the upper part of the profile of humus - accumulation horizon. With the development of the agricultural land that is arable horizon. Under it may occur and the podzolic horizon, but in low-podzol process it may be absent. The following vmyvnoy horizon, gradually turning into a soil-forming rocks.

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Typically the podzolic soils are mainly distributed in the northern part of the region. In the central and southern part is dominated by species of sod-podzolic soils. Tosno Kirishi districts and different prevalence of soils and heavy clay species, and in Tikhvin and Pargolovskaya areas of sandy soils are widespread.