– the most important resource of the biosphere, actively used by humans. Being the main means of agricultural production, soil will remain the main source of human food in the foreseeable future. Soil cover serves as the basis for industrial, transport, urban and rural construction. IN Lately Significant areas of soil are used for recreational purposes, to create nature reserves and protected areas.
Problem rational use and protection of land resources is very relevant; any reduction in the area of agricultural land seriously aggravates the already difficult question providing the world's population with food.
It is estimated that currently 0.3–0.5 hectares of arable land are required to fully provide food per person; for the Non-Chernozem Zone the threshold figure is 0.8 hectares. In the 21st century, the population of our planet is about 6.5 billion, and the share of arable land accordingly decreases to 0.2–0.3 hectares per person.
Land resources(land) occupy about 1/3 of the planet's surface, or almost 14.9 billion hectares, including 1.5 billion hectares occupied by Antarctica and Greenland. The structure of the land in this territory is as follows: 10% is occupied by glaciers; 15.5% – deserts, rocks, coastal sands; 75% – tundra and swamps; 2% – cities, mines, roads. According to FAO (1989), there are about 1.5 billion hectares of soil suitable for agriculture on the globe. This represents only 11% of the world's land cover. At the same time, there is a tendency to reduce the area of this category of land. At the same time, the availability (in terms of one person) of arable land and forest land is decreasing.
The area of arable land per person is: in the world - 0.3 hectares; Russia – 0.88 hectares; Belarus – 0.6 ha; USA - 1.4 hectares, Japan - 0.05 hectares.
When determining the availability of land resources, it is necessary to take into account the unevenness of population density in various parts peace. The most populous countries are Western Europe and Southeast Asia (more than 100 people/km2).
A serious reason for the decrease in land areas used for agriculture is desertification. It is estimated that the area of desertified lands is increasing annually by 21 million hectares. This process threatens the entire landmass and 20% of the population in 100 countries.
It is estimated that urbanization consumes over 300 thousand hectares of agricultural land per year.
Solving the problem of land use, and therefore the problem of food supply, involves two ways. The first way is to improve agricultural production technologies, improve soil conditions, and increase crop yields. The second way is the way to expand agricultural areas.
According to some scientists, in the future the area of arable land can be increased to 3.0–3.4 billion hectares, that is, the total area of land that can be developed in the future is 1.5–1.9 billion hectares. These areas can produce products sufficient to supply 0.5–0.65 billion people (the annual increase on Earth is about 70 million people).
Currently, approximately half of the area suitable for agriculture is cultivated. The limit of agricultural soil use reached in some developed countries makes up 7% of the total area. In developing countries in Africa and South America the cultivable portion of the land is approximately 36% of the area suitable for cultivation.
An assessment of the agricultural use of soil cover indicates great unevenness in the coverage of agricultural production in the soils of different continents and bioclimatic zones.
The subtropical zone has been significantly developed - its soils are plowed to 20–25% of the total area. The small area of arable land in the tropical zone is 7–12%.
The agricultural development of the boreal zone is very small, which is limited to the use of sod-podzolic soils and partly to 8% of the total area of these soils. The largest tracts of cultivated land fall on the soils of the subboreal zone - 32%.
The main reserves for expanding the area of arable land are concentrated in the subtropical and tropical zones. There are also significant potential opportunities for expanding arable land in the temperate zone. The objects of development are, first of all, sod-podzolic swampy soils occupied by unproductive hayfields, pastures, shrubs, and small forests. Swamps are a reserve for the expansion of arable land.
The main ones limiting the development of land for arable land are, first of all, geomorphological (steepness of slopes, rugged terrain) and climatic ones. The northern border of sustainable agriculture lies in the band of 1400–1600° active temperature sums. In Europe, this border runs along the 60th parallel, in the western and central parts of Asia - along 58° north latitude, in the Far East - south of 53° north latitude.
The development and use of land in unfavorable climatic conditions requires considerable material costs and is not always economically justified.
Expansion of arable land areas should take into account environmental and conservation aspects.
Its condition and composition. After all, soils, depending on the region and climatic conditions are different and require different methods processing.
Main types of soils in Russia
For the first time, a scientifically based classification of soils in Russia was prepared in 1886 by Professor V.V. Dokuchaev, who in his developments was based on the nature and conditions of soil formation. Over time, this classification was refined and supplemented by subsequent generations of Russian scientists. Modern classification identifies the main types of soils, the origin of which is closely related to the terrain, various soil-forming rocks, and climate.
On the territory of Russia, from south to north, the following soil zones (or areas in which one main soil type predominates) are distinguished: semi-desert and dry steppes, chernozem-steppe, forest-steppe, taiga-forest and tundra zones.
Soils of semi-desert and dry steppes
The zone of semi-desert and dry steppes is located in the Astrakhan region and Kalmykia, and in the regions Eastern Siberia distributed partially, mainly in the Amur and Minusinsk steppes.
Soils of semi-desert and dry steppes (most often these are brown And chestnut soils ) are formed under conditions of elevated temperature and insufficient moisture, so they contain significantly less humus than chernozems. Despite the fact that such soils have fairly high natural fertility, the lack of moisture, which is especially felt in dry years, does not make it possible to obtain stable harvests every year.
The main ways to increase the fertility of brown and chestnut soils are the following: arrangement of an artificial irrigation system, application of large doses of mineral and organic fertilizers (especially under irrigated conditions), combating wind erosion (planting at the boundaries of the site), deep loosening and snow retention.
Chernozem-steppe soils
The black earth-steppe zone is located north of the zone of semi-desert and dry steppes. In the Asian part of Russia, the chernozem-steppe zone reaches the Ob River, and borders Kazakhstan from the south. Within the European part of our country, it occupies a continuous territory, and its southern border coincides with the State border of Ukraine and Russia.
Chernozem-steppe soils or black soils formed in a moderately warm climate, limited quantity precipitation, flat terrain and abundant steppe. Such soils have the highest fertility rates, which were created over several millennia: steppe plants died off every year, and their remains served as food for insects and microorganisms, which gradually turned them into humus. Thus, phosphorus and nitrogen, which are necessary for full development, gradually accumulated in the soil. Individual soil particles stuck together into humus into lumps, took the form of small grains and formed a strong granular and fine-grained structure of chernozems.
If you are the happy owner of a summer cottage with chernozem soil cover, then in order to obtain consistently high yields you will first need to take measures to preserve and increase the natural fertility of the soil. Despite the fact that chernozems are characterized by high fertility, they contain few easily accessible nutrients for, which is why they need to be periodically fertilized (phosphorus fertilizers play a primary role here), as well as increase the activity of soil microflora (for example, at the end of the season, bury annual grasses in the soil).
Forest-steppe soils
The forest-steppe zone is located north of the chernozem-steppe zone, and its southern border runs in the European part of our country through the cities of Ufa, Ulyanovsk and Tula, and in the Asian part through Chita, Ulan-Ude, Irkutsk, Kemerovo, Novosibirsk, Omsk and Chelyabinsk. Characteristic feature This zone is characterized by the tortuous outline of its borders and uneven location in the regions of Eastern Siberia.
The forest-steppe zone is characterized by gray forest soils , which are formed under conditions of flat-undulating terrain with ravines and depressions, and a moderately warm climate. All precipitation that falls in this zone evaporates almost completely. Gray forest soils are formed mainly under steppe and meadow soils, and only partially under cover deciduous forests. The saturation of loess-like loams with solid bases, the abundance of plant residues and the slightly acidic reaction contribute to the accumulation of nutrients and humus in the soil. Under the loess in in this case refers to a porous, non-layered sedimentary rock of a fawn or gray-yellow color, which is rich in calcium carbonate.
Gray forest soils respond well to different kinds mineral and organic fertilizers. Soils with slightly saturated bases and high acidity require liming. To improve the water-physical properties of gray forest soils, the following measures are required: deep loosening, sowing of perennial soils, destruction of the soil crust, preservation and accumulation of moisture.
Taiga-forest soils
The taiga-forest zone is the most widespread in our country and occupies about 75% of the total area of Russia. The southern border of this zone passes through the cities of Izhevsk, Nizhny Novgorod, Ryazan, Bryansk, goes around the Urals from the south and reaches Tomsk, after which it turns sharply to the south, reaches the State border of Russia and continues to Far East. The northern border of the taiga-forest zone coincides with the southern border of the forest-tundra.
Most often found in the taiga-forest zone sod-podzolic And podzolic soils . Moreover, soddy-podzolic soils, which are formed under the combined influence of soddy and podzolic soil-forming processes, have a number of advantages over podzolic soils: they are less acidic and contain more humus. As for podzolic soils, they have high acidity and are characterized by their inability to resist leaching processes.
Also in the taiga-forest zone you can find marshy soils , which are most often formed as a result of natural swamping of land. Basically, in this zone they do not form continuous massifs and have an island arrangement between sod-podzolic, podzolic soils and other types of soils.
Podzolic, sod-podzolic and marshy soils are characterized by a low content of nitrogen, phosphorus, organic substances and other mineral nutrition elements for. Therefore, to increase their fertility, it is first necessary to add mineral and organic fertilizers to the soil, especially phosphorus and nitrogen. On acidic soils, it is recommended to carry out liming - this not only reduces acidity, but also increases the moisture absorption capacity, and also improves the structure and physical properties soil.
To improve the composition of taiga-forest soils, it is recommended to gradually increase the arable layer, as well as plant legumes and perennial herbs. If the soil is very waterlogged, then an excellent solution to improve its properties is ridge planting of crops, open and closed drainage, narrow-pad plowing and deep loosening.
Swampy soils that have high potential fertility are suitable for treatment methods such as rolling, disking, milling, plowing, closed drainage and the application of mineral fertilizers, of which the most effective are potassium and phosphorus. Also, swampy soils respond well to bacterial preparations, microfertilizers, lime and nitrogen fertilizers.
Tundra soils
The tundra zone is located on the coast of the Arctic Ocean and covers a fairly large territory of Russia. On the tongue northern peoples the word "tundra" means "treeless". One of the characteristic features natural conditions tundra is the presence at a shallow depth of the soil cover of permafrost, which is a waterproof, impermeable layer.
Soils in the tundra zone are formed under small shrubs and lichens in a harsh climate with long winters and short summer. Usually, tundra soils They are very swampy and low in terms of fertility; on their surface there is a thin peaty layer, and under it there is a small horizon with a low humus content.
To improve the properties of tundra soils, it is necessary to carry out reclamation measures that are aimed at improving aeration conditions, eliminating excess moisture and warming the soil - ridge planting of crops, deepening the arable horizon, drainage, frequent loosening and retention of snow, which prevents deep freezing of the soil in winter. In order to increase the biological activity and fertility of tundra soils, it is necessary to apply large doses of mineral and organic fertilizers.
So, as noted, the type of soil may depend on many factors: the location of your site, climate, vegetation, soil-forming rocks, etc. Therefore, before starting work on improving the condition and composition of the soil on the site , you need to decide what type it belongs to. The choice of a set of measures aimed at creating favorable conditions for the growth of trees, herbs, and others, as well as increasing the productivity of your garden plot, will depend on this.
P.S. The map is enlarged by pressing the left mouse button.
The distribution of the main types of soils on the Earth's surface is subject to the law of geographic zonation, as V.V. Dokuchaev established about 100 years ago.
In Russia, latitudinal zoning is more pronounced than in other countries due to the large extent of our country from north to south and the predominance of flat terrain.
On the vast plains of Russia, the following zonal soil types successively replace each other: tundra, gley, podzolic and sod-podzolic, gray and brown forest soils, chernozems, chestnut soils, brown soils of semi-deserts, gray-brown and gray soils. In the humid subtropics, yellow soils and red soils are common.
A characteristic feature of soil change in the mountains is altitudinal zonation.
Soil types are distinguished based on their fertility, structure, mechanical composition, etc.
In the north, tundra-gley soils are common. They are low-power, waterlogged, and contain little oxygen.
Common in the forest zone different types soil In the taiga subzone, podzolic soils form under coniferous forests. As a result of the decomposition of pine litter, acids are formed, which, under conditions of excess moisture, contribute to the decomposition of mineral and organic soil particles. Heavy precipitation washes the soil and carries dissolved substances from the upper humus layer to the lower soil horizons. As a result top part soils acquire the whitish color of ash (hence the name “podzols”). In areas where deciduous trees grow along with conifers, soddy-podzolic soils are formed. Their upper horizon is enriched with humus and ash elements.
In the larch forests of Eastern Siberia, permafrost is common with low precipitation. This makes it difficult to wash the soil. Therefore, weakly podzolized permafrost-taiga soils are developed here.
All taiga soils have a thin humus horizon, low content of many minerals, and an acidic reaction. However, soil fertility can be easily restored with the help of fertilizers.
Podzolic and soddy-podzolic soils occupy more than half of the area of Russia.
More fertile gray forest and brown forest soils are formed under deciduous forests. Here the layer of litter (litter) rich in ash elements increases. They neutralize organic acids, resulting in the formation of soils with a high humus content.
Under oak forests Gray forest soils are formed, and brown forest soils are formed under the beech-hornbeam soils.
To the south, in the forest-steppe zone and in the northern part of the steppe, the most fertile soils are formed - chernozems. There is practically no leaching regime here, and steppe plants provide a large number of organic matter annually. Therefore, a thick - up to 100 cm - layer of humus is formed.
In the arid parts of the steppe zone, chestnut soils are found, which differ from chernozems primarily in their lower humus content.
As you move south, the climate becomes drier and warmer, and the vegetation cover becomes more and more sparse. Due to this, less humus accumulates in the soil. Chestnut, brown semi-desert soils, gray-brown and gray soils are formed here. They are often saline, and when groundwater is close to each other, salt marshes are formed: The diversity of soils in our country is reflected on soil maps of Russia.
Russia is one of the countries most endowed with land resources. Land resources mean the surface of the Earth on which various economic objects, cities and villages can be located. These are to a large extent the resources of the territory. Land resources are characterized by soil quality, climate, topography, etc.
Despite the enormous size of its territory, our country has a relatively small amount of land favorable for life and economic activity of people. More than 10% of the country's area is occupied by unproductive tundra lands, about 13% by swamps and wetlands. Only 13% of Russia's land area is used in agriculture (arable lands, gardens, hayfields, pastures). The share of the most valuable land - arable land - is only about 7.7% of the country's area. More than half (52%) of all arable land is located on black soil. About 80% of all agricultural products in Russia are produced here.
Gray and brown forest soils also play a significant role in agricultural production.
Podzolic and chestnut soils are used mainly for pastures and hayfields.
The amount of arable land is constantly decreasing. The reason for this is the use of agricultural land for the construction of reservoirs, cities, industrial enterprises, and roads.
In all zones, soils suffer from erosion. Erosion has natural causes, but human activity increases erosion many times over. The main culprits of erosion are: destruction of woody vegetation, unregulated grazing, improper plowing, irrational placement of crops, etc.
Soil is an easily degradable and practically irreplaceable species. natural resources. That's why special meaning The problem of rational use of arable land is emerging.
Work to improve land and increase its productivity is called land reclamation.
The main types of reclamation work are different for different natural zones. In the forest zone, wetlands and waterlogged lands are drained, acid soils are sensed, and mineral fertilizers are applied. In the forest-steppe and steppe, the main types of reclamation are irrigation of dry lands, retention of snow in fields, organization of the fight against soil erosion and soil blowing.
In the zone of deserts and semi-deserts, irrigated agriculture predominates, the fight against salinization of fields is carried out, and special work is carried out to consolidate shifting sands.
The soil cover serves as the basis for industrial, transport, urban and rural construction. Recently, significant areas of soil have been used for recreational purposes and to create protected areas. All this contributes to a reduction in the area of agriculture.[...]
For a long time, the growth of agricultural production was achieved by increasing arable areas. This was especially clear in the post-war decades, when in 35 years (from 1940 to 1975) the area of agriculture doubled. According to FAO (1989), there are about 15 million km of soil suitable for agriculture on the globe. This represents only 11% of the world's land cover and 3% of our planet's surface. At first glance, the reserves for expanding agriculture are very large. In reality this is not the case. According to FAO, about 70% of the world's land surface is unsuitable for agriculture, and the best soils are already used for agricultural production. How are land resources used, in which soil groups still have reserves? The answers to these questions are vital.[...]
Currently, approximately half of the area suitable for agriculture is cultivated. 32 million km2 are occupied by grassy landscapes - natural pastures. Forests cover 40.5 million km2. Note that more than 2 million km2 are occupied by cities, industrial enterprises, roads, power lines and pipelines. These losses continue to increase.[...]
The limit of soil use for agriculture reached in some developed countries is 70% of the total area suitable for agriculture. In developing countries, mainly in Africa and South America, the cultivated portion is equal to about 36% of the area suitable for cultivation.[...]
From the data of N.N. Rozov and M.N. Stroganova (1979), presented in table. 57, it follows that the largest tracts of cultivated land fall on the soils of the subboreal zone. They are the most developed among other bioclimatic zones. Soils of deciduous forests and prairies (brown forest, dark prairie soils) are plowed by 33%, steppe soils by 31%, and even soils of subboreal deserts and semi-deserts by 2% of the area occupied by each of the listed soil groups. In general, the arable lands of the subboreal zone account for only 3.4% of the world’s soil cover.[...]
The subtropical zone has been significantly developed. Soils of seasonally moistened landscapes (brown, gray-brown) are plowed by 25% of their total area, soils of humid subtropical forests (red soils and yellow soils) by 20%. All arable land in this belt accounts for 3.1% of the world's soil cover. The same area of arable land in the tropical zone. However, the territory of this belt is 4 times larger than the subtropical one, so the degree of development of tropical soils is low. Soils of red and yellow ferralitic soils are plowed on only 7% of the area occupied by these soils, and soils of seasonally wet landscapes (red savannah, black drainage) - by 12%.[...]
The agricultural development of the boreal zone is very small, which is limited to the use of soddy-podzolic and partly podzolic soils (8% of the total area of these soils). The cultivated lands of the boreal belt form only 1% of the world's soil cover. The soils of the polar zone are not used in agriculture.[...]
The unevenness in the coverage of different soils by agriculture clearly shows which soils are most profitable and convenient to cultivate. These are chernozems, dark prairie soils, gray and brown forest soils. It is no coincidence that in the first half of the 20th century. half of the world's total agricultural area fell on these soils. Let us recall that the listed soils are plowed in less than half of the territory occupied by them. However, further increase in plowing of these soils is limited by a number of reasons. Firstly, the areas of these soils are heavily populated, they have a diverse industry, and the territory is crossed by a dense network of transport highways. Secondly, further plowing of meadows, rare remaining forests and artificial plantings, parks and other recreational facilities is environmentally dangerous. Therefore, it is necessary to search for reserves in the distribution areas of other soil groups.[...]
According to the forecast of the above-mentioned researchers greatest number arable land in the future should be concentrated in the tropical zone, in second place will be the lands of the subtropical zone, while traditionally considered the main basis for agriculture, the soils of the subboreal zone (chernozems, chestnut, gray and brown forest, dark prairie soils) will take third place.[ ...]
Uneven agricultural use of soils is also typical for Russia. This is due to the fact that a significant part of the territory of our country is located in unsuitable areas for Agriculture conditions. The total area of soils favorable for agriculture does not exceed 10-11% of the entire territory of Russia. Agriculture is concentrated in forest-steppe and steppe landscapes and only partially in the southern regions of the forest zone.