Rational organization agricultural production as the main condition for solving the aggravated food problem in the world is impossible without proper consideration climate resources terrain. Climate elements such as heat, moisture, light and air, along with nutrients supplied from the soil, are required condition plant life and ultimately the creation of agricultural products. Agro-climatic resources are understood as climate resources in relation to stocks Agriculture. Air, light, heat, moisture and nutrients called life factors of living organisms. Their combination determines the possibility of vegetation of plant or animal organisms. The absence of at least one of the factors of life (even in the presence of best options all others) leads to their death.

Various climatic phenomena (thunderstorms, cloudiness, winds, fogs, snowfalls, etc.) also have a certain effect on plants and are called environmental factors. Depending on the strength of this effect, plant vegetation is weakened or enhanced (for example, when strong wind transpiration increases and the need of plants for water increases, etc.). Environmental factors become decisive if they reach a high intensity and pose a threat to plant life (for example, frost during flowering). In such cases, these factors are subject to special consideration. These representations are used to identify the so-called limiting factors in specific areas.

Air. Air environment characterized by constancy gas composition. Specific gravity components of nitrogen, oxygen, carbon dioxide and other gases - spatially slightly changes, so they are not taken into account when zoning. Oxygen, nitrogen and carbon dioxide (carbon dioxide) are especially important for the life of living organisms.

Light. The factor that determines the energy basis of the entire variety of plant life (their germination, flowering, fruiting, etc.) is mainly the light part of the solar spectrum. Only in the presence of light in plant organisms does the most important physiological process, photosynthesis, arise and develop.

The part of the solar spectrum directly involved in photosynthesis is called photosynthetically active radiation (PAR). The organic matter created due to the absorption of PAR during photosynthesis makes up 90-95% of the dry mass of the crop, and the remaining 5-10% is formed due to mineral soil nutrition, which is also carried out only simultaneously with photosynthesis.

When assessing light resources, the intensity and duration of illumination (photoperiodism) are also taken into account.

Warmly. Each plant requires a certain minimum maximum of heat to develop. The amount of heat required by plants to complete the growing cycle is called the biological sum of temperatures. It is calculated as the arithmetic sum of the average daily temperatures for the period from the beginning to the end of the plant's growing season. Temperature limit of the beginning and end of the growing season, or critical level, limiting the active development of crops, was called the biological zero or minimum. For different ecological groups of crops, the biological zero is not the same. For example, for most grain crops of the temperate zone (barley, rye, wheat, etc.) it is +5 0 С. for subtropical crops (rice, cotton, citrus fruits) +15 0 С.

To account for the thermal resources of the territory, the sum of active temperatures is used. This indicator was proposed in the 19th century. French biologist Gasparin, but theoretically developed and refined by the Soviet scientist G.T. Selyaninov in 1930. He represents with him arithmetic sum all average daily temperatures for the period when these temperatures exceed a certain thermal level: +5 0 С, +10 0 С. To draw a conclusion about the possibility of growing a crop in the study area, it is necessary to compare two indicators: in heat, and the amount of active temperatures that accumulate in a given area. The first value must always be less than the second.

A feature of plants of the temperate zone (cryophiles) is the passage of a phase of winter dormancy, during which the plants need a certain thermal regime of air and soil layer. Deviations from the required temperature interval are unfavorable for normal vegetation and often lead to plant death. The agro-climatic assessment of wintering conditions is understood as taking into account unfavorable meteorological and weather events in the cold season: sharp frosts, deep thaws, causing soaking of crops; a powerful snow cover, under which seedlings ripen; ice, ice crust on the stems, etc. Both the intensity and the duration of the observed phenomena are taken into account.

Moisture. The most important factor The lifeblood of plants is moisture. In all periods of life, a plant requires a certain amount of moisture for its growth, without which it dies. Water is involved in every physiological process associated with the creation or violation organic matter. It is necessary for photosynthesis, provides thermoregulation plant organism, transports batteries. During normal vegetative development, cultivated plants absorb huge volumes of water. Often, from 200 to 1000 mass units of water are consumed to form one unit of dry matter.

Based on the analysis of factors, a comprehensive agro-climatic zoning of the area is carried out.

Agro-climatic zoning is the subdivision of a territory (at any level) into regions that differ in terms of growth, development, overwintering and production in general. cultivated plants.

When classifying agroclimatic resources of the world at the first level, differentiation of the territory is carried out according to the degree of heat supply, in other words, according to macro-differences in thermal resources. On this basis, thermal belts and subbelts are distinguished; the boundaries between them are conditionally drawn - along isolines certain values sums of active temperatures above +10 0 С.

Cold belt. The sums of active temperatures do not exceed 1000 0 C. These are very small reserves of heat, the growing season lasts less than two months. Since temperatures often drop below freezing during this time, open field farming is not possible. The cold belt occupies vast areas in northern Eurasia, Canada and Alaska.

Cool belt. Heat supply increases from 1000 0 С in the north to 2000 С in the south. The cool belt extends in a fairly wide strip south of the cold belt in Eurasia and North America and forms a narrow zone in the south of the Andes in South America. Insignificant heat resources limit the set of crops that can grow in these areas: these are mainly early-ripening, heat-undemanding plants that can tolerate short-term frosts, but are photophilous (plants long day). These are gray breads, vegetables, some root crops, early potatoes, special polar species wheat. Agriculture is focal in nature, concentrating in the warmest habitats. General disadvantage heat and (most importantly) the danger of late spring and early autumn frosts reduces the possibilities of crop production. Arable lands in the cool zone occupy only 5-8% total area lands.

Temperate zone. Heat supply is at least 2000 0 С in the north of the belt up to 4000 0 С in southern regions. The temperate zone occupies vast territories in Eurasia and North America: it includes the entire overseas Europe(excluding southern peninsulas), most of the Russian Plain, Kazakhstan, southern Siberia and Far East, Mongolia, Tibet, Northeast China, southern regions Canada and northern regions USA. On the southern continents the temperate zone is represented locally: it is Patagonia in Argentina and a narrow strip of the Chilean coast Pacific Ocean South America, Tasmania and New Zealand.

In the temperate zone, differences in the seasons of the year are pronounced: there is one warm season, when the vegetation of plants occurs, and one period of winter dormancy. The vegetation period is 60 days in the north and about 200 days in the south. The average temperature of the warmest month is not lower than +15 0 С, winters can be both very severe and mild, depending on the degree of continentality of the climate. The thickness of the snow cover and the type of overwintering of cultivated plants vary in a similar way. The temperate zone is a zone of mass farming; arable lands occupy almost all the spaces suitable for the conditions of the relief. The range of cultivated crops is much wider, all of them are adapted to the thermal regime of the temperate zone: annual crops quite quickly complete their growing cycle (in two or three summer months), and perennial or winter species necessarily go through the vernalization or vernalization phase, i.e. winter dormancy period. These plants are isolated in special group cryophilic cultures. These include the main grain cereals - wheat, barley, rye, oats, flax, vegetables, root crops. There are large differences between the northern and southern regions of the temperate zone. general reserves heat and in the duration of the growing season, which makes it possible to distinguish two sub-belts within the belt:

Typically temperate, with thermal resources from 2000 0 C to 3000 0 C. Mostly long-day plants grow here, early maturing, little demanding on heat (rye, barley, oats, wheat, vegetables, potatoes, grass mixtures, etc.). It is in this subbelt that it is high for winter crops in crops.

Warm-temperate zone, with sums of active temperatures from 3000 0 С to 4000 0 С. A long period vegetation, during which a lot of heat accumulates, allows growing late-ripening varieties of grain and vegetable crops; corn, rice, sunflower successfully vegetate here, vine, many fruit and fruit tree crops. It becomes possible to use intermediate crops in crop rotations.

Warm (or subtropical) zone. The sums of active temperatures range from 4000 0 C to northern border up to 8000 0 С on the south. Territories with such heat supply are widely represented on all continents: the Eurasian Mediterranean, South China, the predominant part of the territory of the USA and Mexico, Argentina and Chile, south African mainland, southern half of Australia.

Heat resources are very significant, however, in winter, average temperatures (although positive) do not rise above +10 0 C, which means the suspension of vegetation for many overwintering crops. The snow cover is extremely unstable, southern half zones are observed, snow may not fall at all.

Due to the abundance of heat, the range of cultivated crops is greatly expanded due to the introduction of subtropical heat-loving species, and it is possible to cultivate two crops per year: annual crops of the temperate zone in the cold season and perennial, but cryophilic species of the subtropics (mulberry, tea bush, citrus, olive, walnut, grapes, etc.). Annuals of tropical origin appear in the south, requiring large sums of temperatures and not tolerating frosts (cotton, etc.)

Differences (mainly) in the mode of the winter season (presence or absence of vegetative winters) make it possible to subdivide the territories of the warm belt into two sub-belts with their own specific sets of crops: moderately warm with sums of active temperatures from 4000 0 С to 6000 0 С and with cool winters and typical a warm subbelt with a heat supply of about 6000-8000 0 С, with predominantly vegetative winters (average January temperatures are above +10 0 С).

Hot belt. Heat reserves are practically unlimited; they everywhere exceed 8000 0 C. The territorially hot zone occupies the most extensive areas of land the globe. It includes the predominant part of Africa, most of South America, Central America, all South Asia and Arabian Peninsula, the Malay Archipelago and the northern half of Australia. In the hot zone, heat ceases to play the role of a limiting factor in the placement of crops. Vegetation lasts all year round, the average temperature of the coldest month does not fall below +15 0 C. The set of cultivated plants possible for growing is replenished with species of tropical and equatorial origin (coffee and chocolate trees, date palm, bananas, cassava, sweet potato, cassava, cinchona, etc.) High direct intensity solar radiation destructive for many cultivated plants, therefore they are grown in special multi-tiered agrocenoses, under the shade of specially left single specimens tall trees. The absence of a cold season prevents the successful vegetation of cryogenic crops; therefore, plants of the temperate zone can grow only in high-mountainous regions, i.e. practically outside the boundaries of the hot zone.

At the second level of agro-climatic zoning of the world, thermal belts and sub-belts are subdivided based on differences in annual modes moisture.

A total of 16 regions were identified with different meanings moisture coefficient of the growing season:

• 1. Excessive moisture of the growing season.
• 2. Sufficient moisture during the growing season.
• 3. Dry growing season.
• 4. Dry growing season (more than 70% chance of droughts)
• 5. Dry throughout the year (the amount of annual precipitation is less than 150 mm. HTC for the growing season is less than 0.3).
• 6. Sufficient moisture throughout the year.
• 7. Sufficient or excessive moisture in summer, dry winter and spring (monsoon type of climate).
• 8. Sufficient or excessive moisture in winter, dry summer (Mediterranean type of climate).
• 9. Sufficient or excessive moisture in winter, dry summer (Mediterranean type of climate).
• 10. Insufficient moisture in winter, dry and dry summer.
• 11. Excessive hydration most years with 2-5 dry or dry months.
• 12. Dry most of the year with sufficient moisture for 2-4 months.
• 13. Dry most of the year with excessive moisture for 2-5 months.
• 14. Two periods of excessive moisture with two dry or dry periods.
• 15. Excessive moisture throughout the year.
• 16. The temperature of the warmest month is below 10 0 C (no assessment of moisture conditions is given).

In addition to the main indicators, the classifications also take into account the most important agro-climatic phenomena of a regional nature (wintering conditions for cryophilic crops, the frequency of occurrence of adverse events - droughts, hailstorms, floods, etc.)

AGROCLIMATE RESOURCES

The rational organization of agricultural production as the main condition for solving the aggravating food problem in the world is impossible without due consideration of the climatic resources of the area. Climate elements such as heat, moisture, light and air, along with nutrients supplied from the soil, are a prerequisite for plant life and, ultimately, for the creation of agricultural products. Therefore, agro-climatic resources are understood as climate resources in relation to the needs of agriculture.

Various climatic phenomena (thunderstorms, cloudiness, fogs, snowfalls, etc.) also have a certain effect on plants and are called environmental factors. Depending on the strength of this effect, plant vegetation is weakened or intensified (for example, with a strong wind, transpiration increases and the need for plants in water increases, etc.). Environmental factors become decisive if they reach a high intensity and pose a threat to plant life (for example, frost during flowering). In such cases, these factors are subject to special consideration. Another pattern has been established: the existence of an organism is determined by the factor that is at a minimum (J. Liebig's rule). These representations are used to identify the so-called limiting factors in specific areas.

Air. The air environment is characterized by the constancy of the gas composition. The specific gravity of the components of nitrogen, oxygen, carbon dioxide and other gases varies little spatially, and therefore they are not taken into account when zoning. Oxygen, nitrogen and carbon dioxide (carbon dioxide) are especially important for the life of living organisms.

Light. The factor that determines the energy basis of the entire diversity of plant life (their germination, flowering, fruiting, etc.) is mainly the light part of the solar spectrum. Only in the presence of light in plant organisms arises and develops the most important physiological process is photosynthesis.

When assessing light resources, the intensity and duration of illumination (photoperiodism) are also taken into account.

Warmly. Each plant requires a certain minimum and maximum heat for its development. The amount of heat required to complete the growing cycle is called biological sum of temperatures . It is calculated as the arithmetic sum of the average daily temperatures for the period from the beginning to the end of the plant's growing season. The temperature limit of the beginning and end of the growing season, or the critical level that limits the active development of culture, is called biological zero or minimum. For different ecological groups of crops, the biological zero is not the same. For example, for most grain crops of the temperate zone (barley, rye, wheat, etc.) it is + 5 ° С, for corn, buckwheat, legumes, sunflower, sugar beet, for fruit shrubs and tree crops of the temperate zone + 10 ° С, for subtropical crops (rice, cotton, citrus fruits) + 15°С.

To account for the thermal resources of the territory, we use sum of active temperatures . This indicator was proposed in the nineteenth century. French biologist Gasparin, but theoretically developed and refined by the Soviet scientist G. G. Selyaninov in 1930. It is the arithmetic sum of all average daily temperatures for the period when these temperatures exceed a certain thermal level: +5, +10C.

To conclude about opportunities for crop growth in the study area, it is necessary to compare two indicators with each other: the sum of biological temperatures, which expresses the plant's need for warmth, and the sum of active temperatures that accumulate in a given area. The first value must always be less than the second.

plant feature temperate zone(cryophiles) is their passage winter dormancy phases, during which plants need a certain thermal regime of air and soil layer. Deviations from the required temperature interval are unfavorable for normal vegetation and often lead to plant death.

Under the agro-climatic assessment of wintering conditions is meant taking into account adverse meteorological and weather phenomena in the cold season: sharp frosts, deep thaws, causing soaking of crops; a powerful snow cover, under which seedlings ripen; ice, ice crust on the stems, etc. Both the intensity and the duration of the observed phenomena are taken into account.

As an indicator of the severity of wintering conditions for plants, especially trees and shrubs, most often used the average of the absolute annual air temperature minimums.

Moisture. Moisture is the most important factor in plant life. In all periods of life, a plant requires a certain amount of moisture for its growth, without which it dies. Water is involved in any physiological process associated with the creation or destruction of organic matter. It is necessary for photosynthesis, provides thermoregulation of the plant organism, transports nutrients. During normal vegetative development, cultivated plants absorb huge volumes of water. Often, from 200 to 1000 mass units of water are consumed to form one unit of dry matter.

Theoretical and practical difficulty The problems of water supply of plants led to the emergence of many methods and techniques for calculating its parameters. In Soviet agroclimatology, several indicators of moisture have been developed and used (N.N. Ivanova, G.T. Selyaninova, D.I. Shashko, M.I. Budyko, S.A. Sapozhnikova, etc.) and formulas for optimal water consumption (I. A. Sharova, A. M. Alpatyeva). Very widely used hydrothermal coefficient (HTC) - the ratio of the amount of precipitation for a certain period (month, growing season, year) to the amount of active temperatures for the same time proposed in 1939 by G.T. Selyaninov. Its application is based on a well-known assumption, empirically well confirmed: the sum of active temperatures, reduced by 10 times, is approximately equal to the evaporation rate. Therefore, HTC reflects the relationship between inflowing and evaporating moisture.

Assessment of the moisture content of the territory for the growth of agricultural crops is based on the following interpretation of the HTC values: less than 0.3 - very dry, from 0.3 to 0.5 - dry, from 0.5 to 0.7 - dry, from 0.7 to 1.0 - insufficient moisture, 1.0 - equality of moisture input and output, from 1.0 to 1.5 - sufficient moisture, more than 1.5 - excessive moisture (Agroclimatic Atlas of the World, 1972, p. 78).

In foreign agro-climatic literature, many indicators of territory moisture are also used - the indices of K. Thornthveit, E. De-Martonne, G. Walter, L. Emberge, V. Lauer, A. Penk, J. Mormann and J. Kessler, H. Gossen, F Banyulya and others. All of them, as a rule, are calculated empirically, therefore they are valid only for regions limited in area.

In the context of the growth of the world's population, the problem of providing it with food becomes more and more acute. Emissions into the atmosphere, deteriorating natural conditions, the anthropogenic factor, intensive agriculture lead to a decrease in the level of the planet's resources. Effective use available resources to meet human needs - the way to preserve the planet's biosphere. And in this context, questions arise: what are agro-climatic resources and how to use them rationally?

Natural resources as the basis of agro-industrial production

The basic conditions for meeting the needs of man and society are assigned to the agro-industrial complex as the basis of the world economy. The main factor in the development of this type of activity is the climatic conditions and resources of a particular region. To the question of what agro-climatic resources are, ecologists will answer: these are climate properties that provide the potential for agricultural production in a particular area. Or otherwise, these are the indicators that affect the cultivation of agricultural crops. And if it's simple, it's duration daylight hours, the average temperature per day during certain period and humidity - that's what agro-climatic resources are.

Special Science

how separate industry ecology stood out science that studies the influence of climatic factors on the conditions of agriculture. The tasks of agroclimatology are to assess climatic conditions, study of biocenoses of agricultural lands, reduction of the influence of unfavorable natural conditions, experimental studies and observations. But the main task- agro-climatic zoning, drawing up a map of regions, taking into account agro-climatic resources. Characterization of the level of favorable climate for agricultural production is necessary for scientifically based zoning and specialization in technologies and specifics of crop production.

Top Resources for the Farmer

What are agro-climatic resources for a farmer, what are their characteristics?

Rational use

The agro-climatic resources of each region are different and changeable. Regionalization clearly demonstrates this. It is important to remember that although it is renewable Natural resources, but they can go from rich to poor or even unfit for human activity. Technogenic disasters clearly demonstrate to mankind examples of violations of the agro-climatic potential. Most a prime example- exclusion zone in the area Chernobyl nuclear power plant. But other factors, such as: emissions into the atmosphere of chemical and metallurgical industry- can lead to detrimental consequences in the agricultural sector of the region.

Natural factors as a risk area

Some environmental conditions can play the role of risk factors for crop production, leading to an instant loss of almost the entire crop. For example:

• hurricanes and tornadoes;
• long fogs;
• droughts;
• prolonged thunderstorms with lightning;
• late or early frosts;
• hail and dry wind.

Agro-climatic potential of Russia

The vast territory of the country is represented by a variety of climatic zones, which makes it possible to effectively grow a variety of crops.

Even the taiga zones, with their low average daily temperatures and high levels of humidity, allow efficient cultivation of cereals, potatoes and forage grasses.

The middle zone of Russia with the sum of average annual positive temperatures of 1600-2200 degrees and sufficient moisture The soil is used for growing cereals and potatoes.

The most favorable agro-climatic indicators are famous for the territory North Caucasus and the southern part of the Far East.

Climate records in Russia

• The amount of precipitation falling in Altai is 2000 mm per year - the largest in Russia, and the smallest - in the deserts of the Caspian Sea (150 mm per year).
• In the north of Siberia, summer is the coldest (in July, the average temperature never exceeds 0 degrees).
• The most warm winter- in Sochi, and the warmest summer - in the Caspian Sea.
• The Yakut Republic of Sakha has the coldest winter.

The main tasks of mankind

In order to prevent a food crisis on the planet, scientists have identified several priority tasks:

An important factor is consistent international management agriculture, the development of economical and environmentally friendly organic agriculture. It is difficult to overestimate the importance of state support in the transition of farming to the rails of organic agriculture. And Russia is taking deliberate and purposeful steps in this direction.

Our country has a significant variety of agro-climatic conditions. This circumstance is favorable for the cultivation of a wide variety of agricultural crops and their varieties. Correct use natural conditions can provide an almost year-round supply of the population of our country with fresh vegetables and fruits.

The geography of agricultural crops shows that on far south countries cultivated the most late-ripening crops. With the advancement to the north, as the length of the growing season shortens, they are replaced by more precocious and ultra-early ones. The ripening of most crops occurs almost simultaneously - in the fall. As a result, in September-October, an abundance of vegetables, fruits and grapes is created, which are difficult to store, quickly transport and process.

Selection of crops and varieties according to natural areas evolved historically and was determined by two reasons:

1) the desire to receive largest harvest 2) weak connections between individual zones, lack of transport capable of quickly, with minimal losses, transporting fresh products.

AT modern conditions it is possible to make better use of the diversity of our country's climates and to lengthen the period of consumption by the population of fresh vegetables, fruits, berries, gourds and grapes. For this, it is necessary in the hottest regions, along with the cultivation of late crops, which determine here general direction agriculture, to allocate areas for growing the most early-ripening plants that will ripen in late April - early May. In other areas, it is necessary to choose varieties in such a way that from April to December-February the population is provided with fresh vegetables, potatoes, berries, fruits and grapes. Thus, in our country it is possible to have fresh products for 8-10 months a year. Considering that part of the products, without losing nutritional qualities, is stored for 2-3 months (onions, radishes, cabbage, potatoes, berries, apples, pears, etc.), then the population can be provided with fresh vegetables and fruits almost all year round.

This possibility can be shown by the example of grapes. Hundreds of varieties of grapes are cultivated in the Soviet Union. ecological properties. They are classified into five main groups: very early, early, medium, late and very late. In the southern regions Central Asia very early grape varieties ripen in June; very late varieties ripen here in August-September. In the Crimea and Western Transcaucasia, grapes ripen in September-November, etc.

A detailed agro-climatic calculation of the ripening periods of various grape varieties, taking into account heat and moisture in various regions of our country, is given in Fig. 90.

As follows from the figure, with proper consideration of natural conditions, it is possible to distribute the ripening period of grapes in such a way that the population will have it fresh for 7-8 months a year, and with proper storage, up to 10 months. This conclusion has been confirmed by the experiments of research institutions and the achievements of agricultural leaders.

Similar agro-climatic calculations were made for vegetable crops: tomatoes, cucumbers and cabbage. In accordance with them, a continuous supply of fresh vegetables to the population can be ensured from the end of April to March. next year. If the storage of vegetables is improved, then it will be possible in principle to supply the population with fresh vegetables all year round.

Continuous production method fresh food agriculture through the use of a variety of agro-climatic conditions of the country entered the scientific literature under the name of the natural (geographical) conveyor.

In addition to the geographical conveyor, a significant factor in solving the problem of year-round production of fresh products is the greenhouse and greenhouse economy, which is developing especially intensively in our country in last years. So, if in 1968 the area of ​​the entire farm of protected ground was 5948.9 hectares, then in 1970 it increased to 8757.1 hectares. Gross production of greenhouse vegetables alone reached 298,269 tons in 1970. In the future, the average production of greenhouse vegetables per inhabitant of the USSR should increase to 9.5 kg/year.

Rational organization of agricultural production as the main condition for solving the growing food crisis! problems in the world is impossible without proper consideration of the climatic resources of the area. Climate elements such as heat, moisture, light, air, along with nutrients supplied from the soil, are a prerequisite for plant life and, ultimately, for the creation of agricultural products. Therefore, agro-climatic resources are understood as climate resources in relation to the needs of agriculture.

Heat reserves are practically unlimited; they everywhere exceed 8,000°, sometimes over 10,000°. In the Amazonian lowland, heat ceases to play the role of a limiting factor in the placement of crops. Vegetation lasts all year round, the average temperature of the coldest month does not fall below + 20°C. The set of cultivated plants that can be grown is replenished with species of tropical and equatorial origin (coffee and chocolate trees, date palm, bananas, cassava, sweet potato, cassava, cinchona, etc.). The high intensity of direct solar radiation is detrimental to many cultivated plants, so they are grown in special multi-tiered agrocenoses, under the shade of specially left single specimens of tall trees. The absence of a cold season prevents the successful vegetation of cryogenic crops, so plants of the temperate zone can grow only in high-mountain regions, that is, practically outside the boundaries of the hot zone.

2.4 Biological resources

2.4.1 Vegetation

Composition and appearance The Amazon rainforest impresses with the abundance of plant life forms, the exceptional richness of the species composition (approximately 4,000 species of trees alone), the density and complexity of the canopy.

This plant mass, the richest on Earth, has, especially in the west of the Amazon, innumerable resources of food, technical and medicinal raw materials, building and ornamental materials. Amazon pool plays important role in global metabolism, it accounts for about 10% of the production of the Earth's primary biological products.

species composition and appearance forests varies depending on the position in relation to the rivers. Periodic floods of the Amazon and its tributaries have a great influence on vegetation. In this regard, different types of forest vegetation are distinguished on the lowlands: forests in river valleys, flooded for several months a year (the local population calls them "igapo"); forests in river valleys that are flooded for a short time (they are called "varzeya"); forests in the watersheds, not flooded at all (known as "ete"). In addition, the aquatic vegetation of the Amazon itself and other rivers, as well as mangroves on the Atlantic coast, stand out.

The least rich vegetation is along rivers in long-term flooded areas. They are usually devoid of soil cover and are covered with boggy silt, which envelops tree trunks to a height of several meters. The ground vegetation cover and undergrowth are provided with respiratory roots and supporting roots. For igapo, cecropia is typical - a tree medium height with broad whitish leaves and prop roots. There are also many vines and epiphytic plants that bloom brightly and beautifully. The surface of stagnant and slowly flowing waters is covered with various algae and aquatic plants, among which the most remarkable is Victoria regia from the water lily family with leaves up to 2 m in diameter, capable of withstanding a load of up to 50 kg. Its fragrant large flowers during flowering gradually change their color from white to purple, the seeds are edible.

The vegetation of the lowlands, which are only subject to short-term and irregular flooding, is slightly richer in species. The soil cover consists of tropical bog (laterite gley) soils, on which dense four- and five-tiered forests develop. The main background in these forests is usually formed by palm trees, some of them reach a height of 60 m. Representatives of the legume, ficus and euphorbia families are often found. Among the Euphorbiaceae is the famous Hevea, the most common and valuable rubber plant in tropical countries. Common in the lower layers different kinds chocolate tree. Varzea is also characterized by a significant number of vines and epiphytic plants, among which the most beautiful are orchids with their bizarre, diverse and brightly colored flowers. The rich grass cover is full of ferns, bananas and bromeliads.

The forests of unflooded watershed spaces are distinguished by a special splendor and variety of species. They can be considered the richest type of vegetation on Earth. The watershed spaces of the Amazonian lowland are ancient land, on which climatic conditions close to modern ones were established already in the Mesozoic. In these areas, a thick red-colored lateritic weathering crust has formed, which serves as the parent rock for podzolized red-yellow ferralitic soils.

The watershed forests of the Amazon include great amount plant species, some of which also grow in flooded forests. Upland forests no longer have groups of trees that would occupy a dominant position. The abundance of plant species is extremely high, but the number of individuals belonging to one species is usually insignificant. A characteristic tree of the upper tiers is Bertoletia, or Castagna. Giant ceibas, palms, laurels, myrtle, mimosa and legumes grow next to the castagna. Many of them provide valuable building material and ornamental wood, the fruits of others are used for food and for the manufacture of various trade items. In the ground cover there are many different large herbaceous plants with powerful stems and leaves: ferns reaching several meters in height, bromeliads, cannes with large bright flowers; cereals, rushes, maranthus, which are not found in flooded forests, grow. On the trees and on the ground there are many creeping, creeping and climbing plants, the stems of which are not inferior in thickness and strength to ropes.

A continuous cover of tropical rainforests is typical only for the western part of the Amazon. In the east, where the dry period is pronounced, the composition and appearance of the vegetation cover change. Deciduous tree species are found in the forests, and areas of a typical savanna appear on the watersheds.