The soil is composed of solids (mineral and organic), liquid and gaseous phases. For all soils characterized by reduction of organic substances and living organisms from the upper soil horizons to the lower.
The A1 horizon — dark-colored, containing humus, enriched with minerals and has to biogenic processes of the highest value.
The A2 horizon— eluvial layer is usually ashy, light gray or yellowish-gray color.
Horizon — eluvial layer, usually thick, brownish or brown color enriched with colloidal-dispersed minerals.
The horizon — amended soil-forming processes of parent material.
The horizon D — the original breed.
Soil formation occurs on Earth since the origin of life and depends on many factors. The duration of the process of soil formation for different continents and latitudes varies from several hundred to several thousand years.
Currently, human activities becomes the dominant factor in the destruction of soils, lowering and increasing fertility. Human-influenced change parameters and soil forming factors — relief, climate, creates the reservoir is irrigation. On the large areas of reduced soil productivity due to the reduction of humus reserves in the last 20 years has decreased in the Russian Federation to 25 - 30%, and the annual losses amount of 81.4 million tons of Earth today can feed 15 billion people. Careful and competent handling of land has now become the most urgent problem.
Anthropogenic intensification of production contributes to pollution and dehumification, secondary salinization, soil erosion. The main pollutants of the soil are pesticides used for weed control. The regions with significant soil contamination should include Moscow and the Kurgan region, the regions with the average pollution -the Central black earth district, Primorsky Krai, North Caucasus. The soil around the big cities and large enterprises of nonferrous and ferrous metallurgy, chemical and petrochemical industry, machine building, TPP at a distance of a few tens of kilometers are contaminated with heavy metals, oil products, lead compounds, sulfur and other toxic substances. The average content of lead in soils the five-kilometer zone around several of the surveyed cities of the Russian Federation exceeds the maximum permissible concentration of 0.4 — 80 times. The average content of manganese around the enterprises of ferrous metallurgy — 0.05 — 6 times.
Over the last ten years the density of atmospheric fluorides wypadanie around the Bratsk aluminum plant increased 1.5 times, and around Irkutsk — 4 times. Near Monchegorsk contamination of soil with Nickel and cobalt is more than 10 times higher than normal. Soil contamination by crude oil at the point of extraction, processing, transportation and distribution exceed the background dozens of times. Within a radius of 10 km from Vladimir in the Western and Eastern areas of oil content in soil exceeded the background value of 33 times.
Thus, intensive development of industrial production leads to an increase of industrial waste, which together with household waste, significantly affect the chemical composition of the soil, causing deterioration of its quality. Strong pollution of soil by heavy metals along with areas of sulfur pollution produced by burning of coal, leads to a change in the composition of trace elements and the occurrence of man-made deserts.
The changes of microelement content in the soil affects the health of herbivorous animals and humans leads to metabolic disorders, causing a variety of endemic disease of local character. For example, the lack of iodine in the soil leads to thyroid disease, lack of calcium in drinking water and food - to the defeat of the joints, their deformation, stunted growth.
In the soils of podzolic type with a high iron content and its interaction with sulfur is formed sulfur iron, which is a potent poison. As a result, the soil is destroyed microflora (algae, bacteria) that leads to loss of fertility. The soil becomes dead when the content of 2 — 3 g of lead per 1 kg of soil (around some companies lead content in the soil reaches 10-15 g/kg).
In the soil are always present carcinogenic (chemical, physical, biological) substances causing tumors in living organisms, including cancer. The main sources of regional contamination of soil carcinogens — emissions of vehicles, industrial emissions, petroleum products.
The export of industrial and domestic waste in landfills leads to pollution and inefficient use of land, creates a real threat of significant pollution of the atmosphere, surface and ground water, higher transport costs and irrevocable loss of valuable materials and substances.