Names

Deserts and semi-deserts of Russia and the world: names, species, where they are on the map, how they look, description of animals and plants, soil, climate, local residents. What is the climate in deserts and semi-deserts

Issues to consider:

1. Desert characteristic

2. desert vegetation

3. Animal world deserts

4. Desertification

5. Semi-desert

6. Protection of deserts and semi-deserts

7. Occupations of the population of deserts and semi-deserts

1. Characteristics of the desert.

Desert - a geographical zone with a hot, arid climate and sparse sparse vegetation in the temperate subtropical and tropical zones of the Earth.

Desert area is estimated at 31.4 million km 2 (about 22% of land).

Deserts are found on all continents except Europe, and are located within the borders of about 60 countries. In the mountains, the desert forms a high-altitude belt (alpine desert), on the plains - a natural zone.Distributed in the temperate zone of the Northern Hemisphere, subtropical and tropical zones of the Northern and Southern Hemispheres.

Large deserts of the world:

Gobi - Central Asia, Mongolia and northern China

Takla-Makan borders the Pamirs and Tibet from the north. Central Asia

Sahara - North Africa

Libyan desert - north of the Sahara

Namib - southwest coast Africa

Kyzylkum - between the Syrdarya and Amudarya rivers, Uzbekistan, Kazakhstan

Karakum - Turkmenistan

Atacama - Northern Chile, South America

Northern Mexico

Great Victoria Desert

Great sandy desert

Climatic conditions:

One of the main features of the desert is the lack of moisture, which is explained by the negligible (50- 200 mm per year) the amount of precipitation that evaporates faster than seeps into the soil. Sometimes there is no rain for several years. Most of the territory is drainless, and only in some places there are transit rivers or lakes that periodically dry up and change their shape (Lob Nor, Chad, Air). Some deserts formed within the ancient river, delta and lake plains, others on platform land areas. Often deserts are surrounded by mountains or border on them.

Over the course of a long geological history, deserts have changed their boundaries. For example, the Sahara the greatest desert world - stretched for 400- 500 km south of the present position.

Precipitation 50-200 mm per year

Clear days 200-300 per year

Air temperature +45° in the shade. Surface temperature during the day + 50-60 ° (up to 80 ° and even 94 ° - Death Valley), at night + 2-5 ° (sudden changes)

Dry winds, storms. Winter in Russia frost with thin snow cover.

Contrary to the prevailing opinion that the desert is an endless monotonous sea of sand, the most common are rocky deserts, or hamads, often located on plateaus or mountain ranges with remnants of bizarre shapes. Pebble and gravelly deserts stand out among them, impressive with almost complete lifelessness. Parts of such deserts can be seen in the Sahara, the Kyzyl Kum, and on the Arabian Peninsula. Under conditions of a huge daily temperature range, with periodic wetting and drying of rocks, a characteristic shiny dark crust forms on their surface, the so-called desert tan, which protects the rock from rapid weathering and destruction. Often, rocky deserts turn into sandy ones. IN Central Asia they are called kums, in Africa - ergs, in Arabia - nefuds. Sands are easily carried by the wind, forming eolian landforms: dunes, dunes, safes, etc. Single dunes and dunes not fixed by vegetation can move tens of meters per year. Sometimes sand blown by the wind makes a special sound. In such cases, they speak of singing dunes or dunes (in Dagestan, the singing dune is declared a natural monument). But the bulk of the sands are immobile, as they are held by the long roots of shrubs and grasses, which have adapted to the conditions of constant moisture deficiency. The largest sandy deserts of the world include: the Libyan Desert, Rub al-Khali, Nefud, the Great Sandy Desert, the Great Victoria Desert, the Karakum, the Kyzylkum.

Clay deserts develop on clay deposits of various origins. The largest clay deserts: Ustyurt, Deshte-Lut , Deshte-Kevir Betpak-Dala and others. Their relief is characterized by takyrs and sors.

Saline deserts form on saline (saline) soils and are scattered in separate spots among other types of deserts.

TAKYR - flat clay surfaces, almost devoid of vegetation, in the deserts of the subtropical zone, an area of several m2 up to tens of kilometers 2 . In the spring they are usually flooded with water.

SOLONCHAS - soil types of steppe, semi-desert and desert zones. They contain water-soluble salts, 0.5-10% humus. In the Russian Federation - in the Caspian region.

SORs (blinders), closed depressions in deserts Cf. Asia, covered with a crust of salts or a plump layer of salt dust. They are formed in sands due to evaporation and salinization of near-surface groundwater or on strata of salt-bearing bedrock under conditions of an effusion water regime with the formation of solonchaks.

SAHEL (Arabic - coast, outskirts) - the name of the transitional strip (width up to 400 km ) from the deserts of the Sahara to the savannas of West Africa. Semi-deserts and deserted savannas predominate. Precipitation 200- 600 mm in year; frequent droughts.

Desert types

According to their position, they distinguish between continental deserts (Gobi, Takla Makan), located inside the continent, and coastal deserts (Atakama, Namib), stretching along the western coasts of the continents.

Deserts are sandy (Sahara, Karakum, Kyzylkum, Great Victoria Desert), clayey (South Kazakhstan, south of Central Asia), rocky (Egtpet, Israel) and saline (Caspian lowland).

2. Desert vegetation.

Desert vegetation does not form a dense cover and usually occupies less than 50% of the surface, being distinguished by a great originality of life forms and great sparseness.

Plant types:

1. Succulents - agave, aloe, cacti

2. The root system reaches groundwater

(roots 20-30 m ) - camel-thorn

3. Heat-resistant, able to tolerate dehydration - wormwood

4. Ephemeroids - develop over a short period, then rhizomes or bulbs remain in the soil. - tulip, sedge, bluegrass

Xerophytes (from the Greek xeros - dry and phyton - plant), plants adapted to life in arid habitats. Several types: succulents - heat-resistant, but do not tolerate dehydration (agave, aloe, cacti); hemixerophytes - do not tolerate prolonged dehydration, the root system reaches groundwater (sage, camel thorn); euxerophytes - heat-resistant, able to tolerate dehydration (wormwood, gray veronica, some mulleins); poikiloxerophytes - when dehydrated, they fall into suspended animation (some mosses).

Ephemera, annual herbaceous plants, the entire development of which usually occurs in a very short time (several weeks), more often in early spring. Characteristic for steppes, semi-deserts and deserts (for example, dimorphic quinoa).

EPHEMEROIDS, perennial herbaceous plants, the above-ground organs of which develop from autumn to spring and die off in summer, while the underground ones (bulbs, tubers) persist for several years. Characteristic for steppes, semi-deserts and deserts (species of tulip, sedge, bluegrass)

Plant adaptations:

root system deep into the soil;

modified leaves or spines, scales;

pubescence of leaves - contributes to less evaporation;

dropping leaves with the onset of heat;

flowering only in spring.

Sandy deserts of Asia (Karakum, Kyzylkum, mouth of the Volga river)

Herbs, trees, leafless shrubs and semi-shrubs:

white saxaul (5 m),

sand acacia,

silver chingil - shrub,

juzgun,

ephedra,

camel thorn (a genus of shrubs and perennial herbs of the legume family, eaten by camels, root length 20- 30 m.),

grate - cereal,

swollen sedge,

celine (aristida) - cereal

Clay deserts of Asia (Southern Kazakhstan, lower reaches of the Ural River, south of Central Asia)

wormwood,

saltwort,

black saxaul ( 12 m ), wood goes to fuel; green twigs are food for camels and sheep. Good sand binder

bulbous bluegrass,

desert beetroot,

spurges.

Asia. Saline deserts (Caspian lowland)

soleros

Sarsazan gnarled

Africa

Celine (Aristide)

Date palm trees in oases

America

Succulents (agave, aloe, cacti - cereus, prickly pear), yucca

3. Animal world of deserts

Attachments:

protective coloring of sand color,

fast run,

go long without water

fall into hibernation

nightlife,

holes in the sand

bird nests on the ground (on bushes and trees).

Insects and arachnids: scarab, lingering, scorpion, desert locust

Reptiles:foot-and-mouth disease, steppe agama, monitor lizard, round-headed, frilled lizard, land iguana, sand boa, arrow-snake, gyurza, efa, steppe viper, Central Asian tortoise, panther tortoise (Africa).

Birds:Sadzha (grouse), saxaul jay, desert warbler, field pipit, desert coinage, avdotka.

Rodents:jerboas, thin-toed ground squirrel, gerbils, giant mole rat.

Eared hedgehog.

Ungulates:goitered gazelle, antelopes, including gazelles, saiga, wild ass.

Carnivores:wolf, fennec fox, striped hyena, house (reed cat), dune cat, jackal, coyote, manul, caracal, South Russian dressing, honey badger, Cape South African fox.

4. Desertification

The encroachment of the desert on other parts of the earth is called desertification.

Causes:

Overgrazing.

Intensive perennial tillage.

Drought.

The Sahara, moving south, annually takes away 100 thousand hectares of arable land and pastures.

Atacama moving at speed 2.5 km per year.

Thar - 1 km per year.

5. Semi-deserts

semi-deserts - areas combining the nature of steppes and deserts, found in the temperate, subtropical and tropical zones of the Earth (except Antarctica) and forming a natural zone located between the steppe zone in the north and the desert zone in the south.

In the temperate zone of Asia:

from Caspian lowland to the eastern border of China.

In the subtropics:

Anatolian plateau, Armenian Highlands, Iranian highlands, Karoo , Flinders, foothills of the Andes, valleys of the Rocky Mountains, etc.

In the tropics of Africa:

south of the Sahara, in the Sahel zone (desert savannah)

Plants:

Russia:tulips, sedge, bluegrass, wormwood, mullein, saltwort.

America: cacti.

Africa and Australia: bushesand rare low-growing trees (acacia, doum palm, baobab)

Animals:

hares

rodents (gophers, jerboas, gerbils, voles, hamsters), meerkats,

reptiles;

antelope,

bezoar goat,

mouflon,

kulan, Przewalski's horse

predators: jackal, striped hyena, caracal, serval, steppe cat, fennec fox, house

birds,

many insects and arachnids (karakurt, scorpions).

6. Protection of deserts and semi-deserts

Reserves and national parks

Desert:

Semi-desert:

Ustyurt Reserve,

tiger beam,

Aral-Paygambar.

Listed in the Red Book: Bandaging, mole rat, goitered gazelle, saiga, saja, caracal, serval

7. Occupations of the population of the desert and semi-desert

Desert:breeding of sheep, goats and camels, irrigated agriculture and gardening only in oases (cotton, wheat, barley, sugar cane, olive tree, date palm).

Semi-desert:pasture animal husbandry, oasis agriculture is developed on irrigated lands.

Camels live in deserts (one-humped dromedary in Africa, two-humped Bactrian in Asia).

The desert was and remains an extreme natural environment for people's lives, although it was in the desert that ancient civilizations originated and existed: Egypt, Mesopotamia, Khorezm, Assyria, etc. Life usually arose near a well, river or other water source. This is how oases appeared, the first "islands" of life created by human labor. Life in the oases and occupations of the population differed significantly from the conditions of the desert itself, where people are doomed to eternal wandering under the scorching sun and dust storms in search of water. The breeding of sheep and camels has become traditional occupation nomads. Irrigated agriculture and horticulture developed only in oases, where such plants as cotton, wheat, barley, sugar cane, olive tree, date palm, etc. have long been cultivated. Rapid influx population in large oases led to the formation of the first cities.

FAMOUS DESERT IN THE WORLD

GOBI (from Mong. beef - a waterless place), a strip of deserts and semi-deserts in Central Asia, in the south and southeast of Mongolia and in adjacent regions of China. Bounded in the north by mountainsMongolian Altai and Khangai, in the south - Nanshan and Altyntag. Subdivided intoTransaltai Gobi , Mongolian Gobi , Alashan Gobi , Gashunskaya Gobiand the Dzungarian Gobi. Area over 1000 thousand km2 .

Plains prevail at an altitude of 900- 1200 m , composed mainly of rockschalk, Paleogene And Neogene. They alternate with more ancient hillocks, ridges and island ranges (up to 1800 m ). The sloping piedmont plains are dissected by numerous dry channels flowing into closed depressions, which are occupied by drying lakes, solonchaks or hard clay surfaces; there are also small massifs of shifting sands.

The climate is sharply continental temperate zone(temperature fluctuations from -40 ° C in January to + 45°C in July). Precipitation per year falls from 68 mm in the northwest of the Alashan Gobi to 200 mm in the northeast of Mongolia; there is a summer maximum. There are almost no rivers with a constant flow, most of the channels are flooded only in summer. The soils are gray-brown and brown, often in combination with sandy desert soils, solonchaks and takyrs. Characteristic are carbonate, gypsum-bearing, and coarse gravelly soil varieties.

Desert vegetation is sparse and sparse. On the plateau and piedmont plains there is small-shrub gypsophilous vegetation (blackberry, double-leaved, teresken, reaumuria, several types of nitrate and saltwort). On the salt marshes, in addition to nitrates and saltworts, there are tamarisks, potash. On the sands - sandy wormwood, zaisan saxaul, kopek, perennial and annual grasses. In the northeast and east of Mongolia, semi-deserts are common, where, along with wormwood and saltwort, cereal groups are developed, and rare clumps of shrub caragana are found. A wild camel, a donkey-kulan, a Przewalski's horse, several species of antelope, many rodents and reptiles have been preserved. Many endemic species of flora and fauna. Big Gobi Nature Reserve (within Mongolia).

Animal husbandry (small cattle, camels, horses, to a lesser extent - cattle). For water supply great importance have fairly abundant groundwater. Agriculture is developed only along the river valleys.

KYZILKUM, desert in Wed. Asia, in the interfluve of the Amu Darya and Syr Darya, in Uzbekistan, Kazakhstan and partly in Turkmenistan. OK. 300 thousand km2 . Plain (height up to 300 m ) with a number of closed depressions and isolated mountain ranges (Sultanuizdag, Bukantau, etc.). Most of it is occupied by ridge sands; there are many takyrs in the northwest; there are oases. Used as pasture.

SAHARA, the desert in Africa, the largest in the world. St. 7 million km2 . On the territory of the Sahara are completely or partially the states of Morocco, Tunisia, Algeria, Libya, Egypt, Mauritania, Mali, Niger, Chad, Sudan. OK. 80% of the Sahara are plains 200- 500 m . In the north-east there are drainless depressions: Qattara (133 m), El-Fayoum, etc. In the central part - mountain ranges: Ahaggar, Tibesti (Mount Emi-Kusi, 3415 m , the highest point of the Sahara). Rocky and gravelly (hamady), pebble (reg) and sandy (including ergi) deserts predominate. The climate is tropical desert: rainfall in most parts of the territory is less 50 mm per year (on the outskirts of 100 - 200 mm ). Average January temperatures are not lower than 10 °С; absolute maximum 57.8 °С, absolute minimum -18 °С (Tibesti). Daily amplitudes of air temperature are more than 30 °C, soil - up to 70 °C. In addition to the transit river. Nile and parts of Niger, no permanent streams. Dry channels of ancient and modern watercourses (wadis or uedas) predominate. Groundwater feeds numerous oases. Vegetation cover is extremely sparse, sometimes absent. Agriculture (date palm, cereals, vegetables) in oases. Nomadic and semi-nomadic animal husbandry.

TAKLA-MAKAN, a desert in western China, one of the largest sandy deserts in the world. Length from west to east over 1000 km, width up to 400 km , the area of sands is over 300 thousand km2 .

It was formed under conditions of long-term accumulation of sediments within the Tarim Basin, which is composed mainly of alluvial deposits (of the Tarim River and its tributaries), partially blown over. The surface is flat, gradually decreasing to the north and east of 1200- 1300 m to 800- 900 m . In the west, single ridges rise above Takla Makan (the highest point is Mount Chongtag, 1664 m ) composed of sandstones.

Most of the territory is covered with sands up to 300 m . Dunes predominate in the southwest, and sandy ridges of complex configuration (including large ones, sometimes stretching for 10- 13 km , - the so-called whale backs), sand pyramids (height 150- 300 m ), etc. On the outskirts of Takla-Makan, large areas are occupied by solonchaks.

The climate is moderately warm, sharply continental, with negligible (less 50 mm per year) the amount of precipitation. The atmosphere is highly dusty. The rivers flowing from the Kunlun penetrate into the depths of the Takla-Makan for 100 200 km , gradually drying up in the sands. Only the Hotan River crosses the desert and in summer brings its waters to the Tarim River, which flows along the western and northern outskirts of the Taklamakan.

Depth groundwater in relief depressions (within ancient deltas and old rivers) 3- 5 m , they are usually difficult to access for plants, so most of the territory is devoid of vegetation and only in places with a close occurrence of groundwater there are rare thickets of tamarisk, saltpeter, and reed. Along the outskirts of Takla-Makan and river valleys, poplar turanga, sucker, camel thorn, annual saltwort, saxaul are found. The animal world is poor (rare herds of antelopes, hares, gerbils, jerboas, voles); in the river valleys - wild boars.

Separate oases (mainly in the valleys of the Tarim and Yarkand rivers). There is no permanent population. Near the southern outskirts of Takla Makan, among the sands, are the ruins of ancient settlements confined to dry valleys.

ATACAMA (Atacama), a desert in northern Chile, in the South. America, along the coast of the Pacific Ocean, between 22-27 ° S. sh.; rainfall less 50 mm in year. River crosses. Loa. Large deposits copper ores (Chuquicamata, El Salvador), saltpeter (Taltal), table salt, borax.

ADDITIONAL MATERIAL

Przewalski's Horse (Equus caballus), an equine mammal of the equine genus. body length 2.3 m , height at withers about 1.3 m . This is quite a typical horse, densely built, with a heavy head, thick neck, strong legs and small ears. Its tail is shorter than that of a domestic horse, its mane is erect and short. The color is sandy-red or red-yellow. The mane and tail are black-brown, a black-brown belt runs in the middle of the back, the end of the muzzle is white. In summer the hair is short and tight, in winter it is longer and thicker.

This wild horse was discovered and described in Central Asia by N. M. Przhevalsky in 1878. Once it was widespread, but by the end of the 19th century it was preserved only in the south-west of Mongolia (in Dzungaria), where in 1967-1969 it was seen (in natural conditions) in last time. Przewalski's horse herds consisted of 5-11 mares and foals led by a stallion. They were very mobile and constantly moved, which was determined both by poor winter pastures and uneven rainfall in their habitats. Constant migrations have led to the fact that these horses have become very hardy and strong. From fights with domestic stallions, they always came out victorious.

The main reason for the destruction of the population in natural conditions is fishing (hunting, poaching) and competition for watering places with livestock. Almost immediately after the discovery of the animals, the owner of the Askania-Nova park F. Falz-Fein and later the animal dealer K. Hagenbeck began to look for ways to get these rare animals. Various means were used in this struggle. Hagenbeck, having learned about Falz-Fein's suppliers in Biysk, bought 28 foals with the help of his agents. Despite the fact that by the beginning of the 20th century 52 thoroughbred Przewalski's horses were brought to Europe, only three pairs served as a source for breeding. The Przewalski's horse is kept in many zoos around the world; several dozen individuals live in semi-free keeping in the Askania-Nova reserve. An international plan for the reintroduction of the Przewalski horse in original locations habitat - in the mountain-steppe zone of Mongolia.

Jerboas (Jerboa, Dipodidae) - a family of mammals of the order of rodents; includes 11 genera and about 30 species, including three-toed pygmy jerboas, big jerboa, long-eared jerboa, furry-legged jerboa. jerboas are characterized by a large head with a blunt muzzle, long rounded ears, large round eyes and long vibrissae, a short, curvy body (body length 4- 26 cm ), small front legs, powerful jumping hind limbs. Large ears, eyes and long whiskers testify to the high development of hearing, twilight vision and touch, which are necessary for jerboas when searching for food and protecting themselves from enemies at night. Small front legs serve to grasp and hold food, as well as to dig holes, in which jerboas achieve great skill. The hind limbs are jumping, and in connection with this function they are greatly modified: the foot is elongated and the three middle metatarsal bones grow together into one common bone, called the tarsus. The tail plays an important role in movement: it serves to maintain the balance of the body when jumping, especially when turning sharply at a fast gallop. A black and white tassel at the end of the tail in many species is called a banner and serves as a signaling tool for intraspecific communication. The incisors, in addition to gnawing food, serve to loosen the soil when digging holes, while the limbs are used mainly for raking loosened soil.

Jerboas are distributed from North and Northeast Africa, Southeast Europe, Asia Minor and Western Asia through the Caucasus, Central Asia, Kazakhstan, the extreme south of Siberia (Altai, Tuva, Transbaikalia) to Northeast China and Mongolia. They are mainly found in semi-desert and desert landscapes, only a few species inhabit the steppe zone, and some penetrate mountains to a height higher than 2 km above sea level. Different species have developed adaptations to living on loose or dense soils, and therefore jerboas can be found in sandy, clayey, and rubble semi-deserts and deserts.

Jerboas are typically nocturnal animals. Before dawn, they hide in burrows that they build themselves. The main burrow of the jerboa runs obliquely below the surface with one or more blind escape burrows coming close to the surface. The main passage for the day is clogged with an earthen plug, which is called a penny. On this penny, which has not yet dried out in the early morning, you can find a jerboa hole. If you start digging a habitable hole, then the animal knocks out the ceiling of one of the emergency passages and jumps out through it. In the far part of the main passage, the jerboa digs a hole with a rounded living chamber, which is lined with finely gnawed blades of grass. winter period jerboas spend in deep hibernation in their burrows.

Jerboas feed on the seeds of various plants, lily bulbs, which they dig out of the ground. The diet also includes green parts and plant roots, and in some species a significant proportion of the diet is animal feed (small insects and their larvae). In spring and summer, the reproduction of animals occurs, the female gives birth to 1-8 cubs (usually 2-5).

Jerboas play an important role in desert biocenoses. They have a significant impact on the soil and vegetation cover, serve as food for desert predators. In many areas, jerboas are background animals. Some species damage plants that strengthen the sands; they can be carriers of pathogens of a number of infectious diseases of animals and humans.

GINGERS (Gerbillinae), a subfamily of mammals of the order of rodents; includes about 100 species, united in 13 genera, including dwarf, small, large, short-eared, fat-tailed gerbils, taters (barefoot gerbils). Outwardly, gerbils resemble rats or mice. Their body length is up to 19 cm , reddish-yellow long tail with a tassel. The back is sandy yellow, the belly is white.

Gerbils are common in the desert steppes and deserts of Africa, Asia and Southeast Europe. They feed mainly on plant foods, but can also eat small invertebrates. They do not hibernate for the winter, but in cold weather they do not leave their holes for a long time, eating prepared supplies. Many breed all year round, females bring several litters from 2 to 12 cubs. Gerbils are carriers of plague pathogens, tick-borne typhus, they harm agricultural land. These animals are often kept at home.

Gazelle (Gazella subgutturosa), artiodactyl mammal of the genus of true gazelles (Gazella) of the subfamily of gazelles (Antilopinae); forms 2-4 weakly expressed subspecies. Body length 95- 125 cm , height at the withers 60- 75 cm, weight 18-33 kg . Males have black and lyre-shaped horns up to 40 cm . Females are usually hornless. The coloration of the upper body and sides is sandy. The underside of the body, the neck and the inside of the legs are white. The tail is two-colored: the main part is sandy, the end is black. When a frightened gazelle runs, it raises it to the top, and the tail stands out sharply against the background of a white mirror. For this feature, among the Kazakhs and Mongols, the gazelle was called the black tail (kara-kuiruk, hara-sulte). Young goitered gazelles have a pronounced facial pattern in the form of a dark brown spot on the bridge of the nose and two dark stripes stretching forward from the eyes.

Goitered gazelle is distributed in Western, Central and Central Asia, South Kazakhstan, and also in Eastern Transcaucasia. It lives on flat, hilly deserts and cereal-salt semi-deserts. As good runners, goitered gazelles prefer areas with dense soil, avoiding free-flowing sands. In summer, they graze in the morning and in the evening, and spend the hottest time on the hay, saving moisture. Beds are located on level ground near trees, often favorites, and bushes. The goitered gazelle moves after the shadow of the tree, hiding from the sun, first of all, its head. Raised from the prone, the goitered gazelle quickly jumps up and rushes at a speed of 55- 60 km/h about 200- 300 m , then inspected. In winter, it grazes almost all day.

Goitered gazelles feed on herbaceous or shrubby plants, choosing the most moisture-saturated grasses in summer: barnyard grass, onions, ferulas. Goitered gazelles usually go to watering places with open and flat banks without dense coastal thickets for 10- 15 km once every 3-7 days. They are able to quench thirst not only fresh, but also brackish water(including from the Caspian Sea). The grass that goitered gazelles eat can also contain a significant amount of salt.

In spring and summer, animals are kept singly or in small groups of 2-5 heads. In autumn and winter, they gather in herds from several tens to hundreds of heads. Then the race happens. The beginning of the rut is preceded by the arrangement of rutting latrines by the males. In September, males dig small holes with the hooves of their front legs and leave their excrement there. Other males, finding such holes, may throw away old excrement and leave their own there. Obviously, such holes serve as marks occupied territory. Pregnancy of females lasts 5.5 months. In May, the female brings one, rarely two cubs. Newborns for the first days only lie on a bare piece of land. The sandy-brown coloring of the goitered gazelle so merges with the soil that you can easily step on the baby without noticing it. The cub begins to follow its mother and feed on its own in two weeks. Main natural enemy gazelle - wolf.

In captivity, the gazelle is well tamed and breeds, but does not live long. The goitered gazelle population is declining, although work is underway to restore the number of animals. A subspecies from the Arabian Peninsula (Gazella subgutturosa marica) is listed in the International Red Book.

FENECUS (Fennecus zerda) - view predatory beast wolf families. It looks like a miniature fox. body length approx. 40 cm , tail to 30 cm ; weight 1.5 kg ; ears are large (up to 15 cm ) and wide. The coat is long, reddish-cream above, fawn or almost white; the tip of the fluffy tail is black. Fenech lives in the deserts of North Africa and Southwest Asia. It is active at night and spends the day in a deep burrow. Huge ears allow Fenech to catch the slightest rustle. In case of danger, he burrows into the sand. When hunting, the fennec fox can jump high and far. It feeds on small rodents, birds and their eggs, lizards, insects, carrion, and plants. Pregnancy in a female lasts 51 days. Cubs (2-5) will be born in March-April in a burrow with a nesting chamber lined with grass, feathers and wool.

JACKALS, a group of species of carnivorous mammals of the wolf family. The most common is the Asian jackal (Canis aureus), which appearance looks like a small wolf. His body length is 85 cm , tail about 20 cm ; weight 7–13 kg. The color of the coat in winter is fawn, dirty yellow, with a noticeable red and black tint, the tail is reddish-brown with a black end. It is found in the south of Eurasia, in North Africa; in Russia, mainly in the North Caucasus. The Asian jackal prefers to settle in thickets of bushes and reeds, on plains, near rivers, lakes and seas. It is less common in the foothills. As shelters, the jackal uses natural niches and depressions, crevices among stones, and sometimes abandoned burrows. The animal is active mainly in the dark, but often during the day. It migrates only in search of food.

The jackal is omnivorous, but feeds mainly on small animals: rodents, birds, fish, as well as insects, carrion and the remains of prey large predators. Also eats fruits and berries, including grapes, watermelons, melons, plant bulbs. Living near the villages, he hunts for poultry. When going hunting, the jackal emits a loud howl, which is picked up by all its relatives located nearby. They often hunt alone or in pairs. The jackal forms pairs for life, the male takes an active part in creating a hole and raising offspring. The rut takes place from January to February. Pregnancy lasts about 2 months. Usually 4-6, less often 8 puppies are born. The Asian jackal is a carrier of dangerous diseases (rabies and plague). It has no commercial value.

The jackal (Canis mesomelas) and the striped jackal (Canis adustus) live in East and South Africa. In their lifestyle and habits, they are similar to the Asian jackal. The Ethiopian jackal (Canis simensis) is found in Ethiopia. Outwardly, he looks like a dog with a fox head. A wide black stripe stretches along the middle of the back, sharply delimited from the red sides and limbs. The belly is white, the tail is long red, with a black end. Ethiopian jackal lives in the mountains at a height 3000 m , it feeds on rodents and hares. Its population is small and this animal is protected.

COYOT (prairie wolf, Canis latrans), predatory mammal wolf families. body length approx. 90 cm , tail - 30 cm . Erect ears, a long fluffy tail, which, unlike a wolf on the run, keeps lowered down. The coat is thick, long, grayish or reddish-brown in color on the back and sides, very light on the belly. The end of the tail is black. The coyote is distinguished by a developed higher nervous activity, it is able to adapt to a changing environment.

Coyote lives in the prairies and steppes of North and Central America. Runs into the woods by chance. His lifestyle has a lot in common with the jackal. The lair suits in caves, hollows of fallen trees, deep holes. The loud howl of the coyote is an integral part of the color of the prairies. It feeds on rodents, hares, rabbits, birds and lizards, sometimes fish and fruits, and does not disdain carrion. Rarely attacks domestic animals (goats, sheep). Hunts alone or in packs. destroys a lot of harmful rodents. It is completely safe for humans. Pairs are formed for life, the rut takes place in January-February. Pregnancy lasts 60-65 days. In a brood 5-10, sometimes up to 20 cubs.

CARACAL (Felis caracal), a predatory mammal of the cat family, genus of cats. Body length 65- 82 cm , tail 20- 31 cm ; weight 11- 13 kg . In appearance and tassels on the ears, it resembles a lynx. But it has a thinner, slender body, on high thin legs; also has a uniform light red color. There are small black markings on the muzzle and ears, the ends of the ears are decorated with tassels.

It lives in the deserts of Africa and Asia, including in the south of Turkmenistan. It hunts mainly at night, and during the day it takes refuge in abandoned burrows. Caracal hides prey and overtakes it with large (up to 4.5 m ) jumps. It mainly feeds on rodents: gerbils, jerboas, ground squirrels, as well as tolai hares; less often birds, small antelopes, hedgehogs, porcupines. Can hunt livestock and poultry.

Cubs (from 1 to 4) are born in early April. In ancient times, caracals were trained to hunt antelopes, hares and birds. It has no commercial value. Few. Caracal is listed in the International Red Book. Protected in the Repetek Reserve.

Kulan (onager, Equus hemionus), equine mammal of the horse genus. Body length 2.0- 2.4 m , height at the withers 110- 137 cm , weight 120- 127 kg . In appearance, the kulan is slender and light. The head is relatively heavy, the ears are longer than those of a horse. The tail is short, with a black-brown brush at the end, like donkeys and zebras. Coloring sandy-yellow color of various shades. The belly and inner parts of the legs are white. From the withers to the croup and along the tail there is a narrow black-brown stripe. The mane is low.

The kulan is distributed in Western, Middle and Central Asia. However, the once large range has shrunk significantly. The number is restored only in reserves, including in the south of Turkmenistan (Badkhyz Reserve). The kulan was brought to the island of Barsakelmes and to the foothills of the Kopetdag. Habitat depends on territorial features. The animal can inhabit hilly plains or foothills, deserts and semi-deserts. With the exception of spring, when pastures are covered with young lush grass, kulans need a daily watering place and do not move further from water bodies than 10 15 km . When threatened, they can reach speeds of 60- 70 km/h without slowing down for several kilometers. There are no strictly defined periods of grazing and rest.

To most animals, except for sheep, the kulan is peaceful, often grazing with goitered gazelle and herds of horses. Mutual communication is developed among these animals, it is worth alerting goitered gazelles, or alarmingly shouting to birds, as a kulan takes off. An angry kulan is very ferocious.

Kulans have well-developed eyesight, hearing and smell. Approach the kulan unnoticed at a distance of 1- 1.5 km impossible. However, he can pass by a motionless person at a distance 1.5 m , and this is due to the peculiarities of his visual apparatus. The click of a camera can be heard from a distance. 60 m . They are silent animals. With a call, reminiscent of a donkey, but more deaf and hoarse, the male calls the herd.

The rut takes place from May to August. During the rut, the male begins to prance in front of the females, raising his head high. Often runs around the herd, jumps, screams, rides on his back, tears with his teeth and throws up tufts of grass.

Even before the start of the rut, adult males drive young kulans out of the herds. During this period, there are serious fights between males. Baring their mouths and flattening their ears, they rush at each other with bloodshot eyes, trying to grab the hock joint. If one succeeds, then he begins to twist the opponent around the axis and gnaw at his neck.

Pregnancy of females lasts 331-374 days, on average 345. Kulanyat will be born from April to August. The first hours they lie motionless, but already on the first day they begin to graze with their mother. The grown up kulanenok becomes very active. When he wants to eat, he walks around his mother, digs the ground near her belly with his foot, throws his legs around her neck. The male protects the cubs from possible attacks by young kulans. Animals breed in captivity. Kulans are protected everywhere, two subspecies - Syrian (Equus hemionus hemippus) and Indian kulan (Equus hemionus khur) are listed in the International Red Book.

CAMELS (Camelus), a genus of mammals of the camelid family of the corn-foot order; includes two species: dromedary (one-humped) and Bactrian (two-humped). Length up to 3.6 m . Camels are characterized by signs: they do not have hooves - their legs end in two fingers with blunt claws, and the lower surface of the foot is protected by an elastic callous cushion. They are common in the deserts of Central Asia (Bactrians), as well as in Africa, Arabia, Asia Minor, India (dromedary).

Camels feed on shrub and semi-shrub hodgepodges, tree leaves, and bulbs. The well-known ability of camels to go without water for a long time is due to the fact that they can tolerate a slight increase in body temperature without increased moisture loss. This feature allows you to spend less moisture on cooling. In addition, moderate dehydration in a camel is not accompanied by thickening of the blood and disruption of its circulation, as in mammals not adapted to desert conditions. Camels are able to drink quickly and a lot (in 10 minutes they drink about 130-135 liters of water).

The rut takes place in winter. Usually one, rarely two cubs are born. Only the Bactrian has survived in the wild. The dromedary is domesticated and used as pack and draft animals, as well as for milk, meat and wool.

Bactrian - domesticated Bactrian camel, differs little from the wild Bactrian camel. Many zoologists do not make a difference between the concepts of a Bactrian camel and a Bactrian. Domestic camels have larger humps, wider feet and well-developed calluses on the knees of their front legs. The proportions of the skull of domestic and wild have small but stable differences. The coat color of domestic camels is variable - from light, sandy yellow to dark brown, while wild ones have a constant reddish-brown-sandy color. The Bactrian camel was domesticated more than a thousand years before our era. How resistant to low temperatures and anhydrous animal conditions, it has become widespread in Mongolia, northern China and Kazakhstan. There are several breeds of domestic bactrian camels- Kalmyk, Kazakh, Mongolian.

DROMEDAR (dromedary, one-humped camel; Camelus dromedarius), a mammal of the camel genus of the callus-footed order. Length approx. 2.1 m , height at the withers 1.8- 2.1 m . Unlike the Bactrian, it has one hump, as well as a shorter and lighter coat. humped camel domesticated in ancient times, probably in Arabia or North Africa. Not found in the wild. It is widely distributed in Africa, Arabia, Asia Minor and Central Asia, India, introduced to Mexico and Australia. Several breeds are known: high-speed riding mahars (North Africa), riding Indian Rajputans, pack Turkmen dromedaries.

The way of life is similar to the Bactrian. It tolerates heat better, but worse - frost. Up to 10 days can do without water. Passes under the saddle in a day 80 km at speeds up to 23 km/h . However, in a caravan, a dromedary travels no more than 30 km , because he must graze for a long time. Herbivorous. The rut takes place in winter. When crossed with a Bactrian, it gives fertile offspring (the so-called bunks), which surpass their parents in endurance. But the offspring when crossing hybrids is weak.

Deserts and semi-deserts are waterless, dry regions of the planet, where no more than 25 cm of precipitation falls per year. The most important factor in their formation is the wind. However, not all deserts experience hot weather; on the contrary, some of them are considered the coldest regions of the Earth. Representatives of flora and fauna have adapted to the harsh conditions of these areas in different ways.

How do deserts and semi-deserts arise?

There are many reasons for the formation of deserts. For example, there is little rainfall because it is located at the foot of the mountains, which, with their ridges, cover it from rain.

Ice deserts formed for other reasons. In Antarctica and the Arctic, the main snow mass falls on the coast; snow clouds practically do not reach the interior regions. Precipitation levels generally vary greatly, for one snowfall, for example, an annual norm can fall. Such snow drifts form over hundreds of years.

Hot deserts are distinguished by the most diverse relief. Only some of them are completely covered with sand. The surface of most is littered with pebbles, stones and other different breeds. Deserts are almost completely open to weathering. Strong gusts of wind pick up fragments of small stones and hit them on the rocks.

In sandy deserts, the wind carries the sand across the area, creating undulating sediments, which are called dunes. The most common type of dunes are dunes. Sometimes their height can reach 30 meters. Ridge dunes can be up to 100 meters high and stretch for 100 km.

Temperature regime

The climate of deserts and semi-deserts is quite diverse. In some regions, daytime temperatures can reach up to 52 ° C. This phenomenon is due to the absence of clouds in the atmosphere, so nothing saves the surface from direct sunlight. At night, the temperature drops a lot, again due to the lack of clouds that can trap the heat radiated from the surface.

In hot deserts, rain is rare, but sometimes there are heavy downpours. After rain, water does not soak into the ground, but rapidly flows from the surface, washing away particles of soil and pebbles into dry channels, which are called wadis.

Location of deserts and semi-deserts

On the continents located in northern latitudes, there are deserts and semi-deserts of the subtropical and sometimes also tropical - in the Indo-Gangetic lowland, in Arabia, in Mexico, in the southwestern United States. In Eurasia, extratropical desert regions are located in the Central Asian and South Kazakh plains, in the basin of Central Asia and in the Near Asian highlands. Central Asian desert formations are characterized by a sharp continental climate.

IN southern hemisphere deserts and semi-deserts are less common. Here are located such desert and semi-desert formations as the Namib, Atacama, desert formations on the coast of Peru and Venezuela, Victoria, Kalahari, the Gibson Desert, Simpson, Gran Chaco, Patagonia, the Great Sandy Desert and the Karoo semi-desert in southwestern Africa.

Polar deserts are located on the continental islands of the near-glacial regions of Eurasia, on the islands of the Canadian archipelago, in the north of Greenland.

Animals

Animals of deserts and semi-deserts for many years of existence in such areas have managed to adapt to the harsh climatic conditions. From cold and heat, they hide in underground burrows and feed mainly on underground parts of plants. Among the representatives of the fauna there are many types of carnivores: fennec fox, cougars, coyotes and even tigers. The climate of deserts and semi-deserts has contributed to the fact that many animals have perfectly developed a thermoregulation system. Some desert dwellers can withstand fluid loss of up to a third of their weight (for example, geckos, camels), and among invertebrates there are species that can lose water up to two thirds of their weight.

IN North America and Asia there are a lot of reptiles, especially a lot of lizards. Snakes are also quite common: ephs, various poisonous snakes, boas. Of the large animals, there are saiga, kulans, camels, pronghorn, it has recently disappeared (it can still be found in captivity).

Animals of the desert and semi-desert of Russia are a great variety unique representatives fauna. The desert regions of the country are inhabited by sandstone hares, hedgehogs, kulan, dzheyman, poisonous snakes. In the deserts that are located on the territory of Russia, you can also find 2 types of spiders - karakurt and tarantula.

Polar bears, musk ox, polar fox and some species of birds live in the polar deserts.

Vegetation

If we talk about vegetation, then in deserts and semi-deserts there are various cactus, hard-leaved grasses, psammophyte shrubs, ephedra, acacias, saxaul, soap palm, edible lichen and others.

Deserts and semi-deserts: soil

The soil, as a rule, is poorly developed, and water-soluble salts predominate in its composition. The ancient alluvial and loess-like deposits predominate among them, which are processed by the winds. Gray-brown soil is inherent in elevated flat areas. Deserts are also characterized by solonchaks, that is, soils that contain about 1% of easily soluble salts. In addition to deserts, salt marshes are also found in steppes and semi-deserts. Groundwater, which contains salts, when it reaches the soil surface, is deposited in its upper layer, resulting in soil salinization.

Completely different are characteristic of such climatic zones as subtropical deserts and semi-deserts. The soil in these regions has a specific orange and brick red color. Noble for its shades, it received the appropriate name - red soil and yellow soil. In the subtropical zone in northern Africa and in South and North America there are deserts where gray soils have formed. Red-yellow soils have developed in some tropical desert formations.

Natural and semi-deserts are a huge variety of landscapes, climatic conditions, flora and fauna. Despite the harsh and cruel nature of the deserts, these regions have become home to many species of plants and animals.

The desert only at first glance may seem like a lifeless territory. In fact, it is inhabited by unusual representatives of the animal and flora able to adapt to difficult climatic conditions. The natural zone The desert is very extensive and occupies 20% of the earth's land area.

Description of the natural zone of the Desert

The desert is a vast flat area with a monotonous landscape, poor soil, flora and fauna. Such landmasses are found on all continents except Europe. The main symptom of the desert is drought.

To the features of the relief natural complex Desert include:

plains;
plateaus;
arteries of dry rivers and lakes.

This type of natural zone extends over most of Australia, a relatively small part of South America, is located in the subtropical and tropical zones of the Northern Hemisphere. On the territory of Russia, deserts are located in the south of the Astrakhan region in the eastern regions of Kalmykia.

The largest desert in the world is the Sahara, which is located on the territory of ten countries of the African continent. Life here is found only in rare oases, and on the territory of over 9,000 thousand square meters. km, only one river flows, communication with which is not available to everyone. Characteristically, the Sahara consists of several deserts, similar in their climatic conditions.

Rice. 1. The Sahara Desert is the largest in the world.

Desert types

Depending on the type of surface, the desert is divided into 4 classes:

Climate features

In terms of describing deserts, it is worth mentioning the features of the climate separately. This natural area is characterized by:

high day temperature , which can drop to 0 degrees Celsius at night. In the northern desert, this mark can reach -40 degrees. Such sharp temperature fluctuations indicate the continental climate of most deserts.
Exceptional dry air . Humidity ranges from 5-20%, which is much lower than normal. The reason for this is extremely rare precipitation, which can fall once every few months or even years. The deserts of South America are considered the driest.

Often in the desert there is a so-called "dry rain". Water droplets drip from ordinary rain clouds, but when they collide with highly heated air, they evaporate even in the layers of the atmosphere, without reaching the ground.

Flora and fauna of the desert

Deserts and semi-deserts are characterized by poor vegetation. As a rule, these are thorny shrubs that have adapted to seek moisture deep in the soil with the help of a powerfully developed root system.

Desert animals are represented by small predators and rodents, reptiles and reptiles.

In and between and the desert in the tropics.

Semi-deserts are formed under conditions. What they all have in common is a long and hot warm period ( average temperature 20-25°С, and up to 30°С in the tropics), strong evaporation, which is 3-5 times the amount (100-300 mm per year), weak surface, internal waters are poorly developed, many drying channels, vegetation is not closed.

In spite of common features, inherent in all semi-deserts, they also have many differences.

1. Semi-deserts of the temperate zone in they stretch in a wide strip (up to 500 km) from the western part of the Caspian lowland, through, to the East. In the Northern and semi-deserts, they are found in shorter broken sections in the inner parts and foothills. From semi-deserts located in the tropical and subtropical zones, they differ in cold winters (up to -20 ° C). here are light chestnut, which brings them closer to the steppe, and brown desert, often saline. If you move south along the semi-deserts of the temperate zone, you will notice that the signs of the steppes are fading and the features of the deserts are intensifying. There are also steppe feather grass and fescue, but among them you can already notice wormwood and saltwort. Of the animals, saigas and turtles are found, snakes and lizards are more common.

2. Semi-deserts of the subtropical zone.

They are mainly located in the transitional part from deserts to mountain steppes in the form of an altitudinal zone in the inland parts and the Andes of America, in western Asia, and especially widely in. The soils here are gravelly, gray-brown and gray soils. There are cereals and different kinds shrubs, a wide variety of cacti. From the animal world, rodents, snakes, lizards predominate.

These are deserted savannahs. They delineate deserts, both inland and oceanic - in Africa and, in South America, the north of the Atacama and the northwest of the Brazilian Plateau, in Asia and in Australia.

The soils here are thin, red-brown. The temperature in tropical semi-deserts does not fall below +10°C even in the coldest months, and in summer it rises to 35°C. Rain falls very rarely here. Precipitation is not more than 200 mm per year. With a lack of moisture, the bark is very thin. The waters in tropical deserts lie very deep and may be partly saline.

In such conditions, only plants that can tolerate overheating and dehydration can live. They have a deep branched root system, small narrow leaves or spines; in some plants, the leaves are pubescent or covered with a wax coating, which protects them from sunlight. These include tree-like cereals, agaves, cacti, sandy acacias.

What are the soils in deserts and semi-deserts?

Peculiarities of soil formation on sands are due to a sharp predominance (90% or more) of sandy fractions (1.0 ... 0.05 mm), structurelessness. Therefore, they have high air permeability (total porosity 38.2...44.2%) and water permeability (more than 100 mm/h), insignificant height of capillary rise from 30...60 cm to 70...80 cm above ground level. water, low water-holding capacity (HB 2.5 ... 10.0%), significant thermal conductivity and the lowest heat capacity, low absorption capacity (1 ... 5 mg eq / 100 g of sand).
The period of time favorable for soil formation is 1.0...1.5 spring months, when the greatest microbiological activity is observed.

Desert sandy soils are formed in the southern deserts under the main soil-forming plant, sedge, with a slight admixture of ephemera and shrubs. They have a thin profile (less than 50...70 cm), poorly differentiated into horizons, in which the content of physical clay and carbonates often differs little from the eolian sandy soil-forming rocks. Humus accumulates in them less than 0.4%; humus type is fulvate. A feature of soil formation here is its discontinuity due to the drift of sand sediment, since its upper layer (3 ... rhizomes, holding the sand together, is located in a layer from 3 ... 8 to 15 ... 20 cm. This horizon is called radicular. It is distinguished by a greater grayishness against a general yellowish background. Below it lies a more compressed and slightly compacted yellowish horizon with brownish and barely noticeable whitishness from carbonates, with abundant vertical sedge roots. In addition to such full-profile soils, incompletely developed and underdeveloped soils are widespread. There are especially many such soils in the Karakum Desert.

Yellowish-gray desert (slightly differentiated desert) soils are the main soil type in the desert zone. These are loose-sandy (physical clay lt; 2.5%), weakly cohesive sandy (2.5 ... 5.0%), cohesive sandy (5 ... 10%) soils. They are predominantly formed on quartz-calcite-feldspar, feldspar-calcite-quartz, gypsum-calcareous, marl and residual saline sands, on sandy-loamy sandy-gravel eluvium of dense bedrocks (sandstones, limestones).
Pale gray desert poorly differentiated (loose sandy, weakly cohesive sandy, cohesively sandy) soils are found in northern deserts. They occupy large areas in the Taukums, Muyunkums, Sary-Ishikotrau, on the Sam massifs, the Caspian Karakum, the Buzachi peninsula, in the Arkala desert, at the foot of the Tarbagatai. Primitive (3...10 cm), thin (10...40 cm), medium-thick (40...70 cm) and rarely thick (70...100 cm) soils were identified among them. In these soils, a change in the mineralogical composition is noticeable. The amount of physical clay increased from 0.6...0.8% in barchan sand to 3...5% in horizon A, and humus, respectively, from 0.02...0.07 to 0.3...0 ,4 %. Carbonates are randomly distributed along the profile.

On eolian sands under wormwood-shrub-ephemeral vegetation, soils have been formed with the following structure: horizon A (0...10 cm) light gray with brownish, silty-cohesive sandy, contains many roots, loose; horizon B (10...36 cm) grayish-brownish with paleness and yellowishness, weakly compacted, silty-cohesive-sandy, contains plant roots, structureless; horizon BC (36...80 cm) yellowish-brown with pale pale, slightly compacted, sandy, with a small number of roots; horizon C yellowish, sandy, carbonate. However, the area of such soils is insignificant, because due to overgrazing of animals, they are deformed to varying degrees, sometimes to the formation of dune sands.
ordinary
Soil cover of semi-deserts

Desert soil cover
sand, sand, one fucking sand...
Soil cover of semi-deserts
The soil cover of the semi-deserts of the CIS, located mainly in the Lower Trans-Volga region and Central Kazakhstan, is formed by automorphic humus-poor solonetsous light chestnut and solonetsous brown desert-steppe soils in combination with solonetzes. Where groundwater is close, solonchaks are formed, in flat depressions, depressions, or estuaries, meadow-chestnut soils, in which there is more humus and less soluble salts than in brown and light chestnut soils.
Semi-desert soils occupy about 6% of the territory of the CIS.
Of the features soil cover semi-deserts of the CIS should be noted as especially characteristic, complexity and solonetzic. Complexity is expressed in frequent shift at a short distance soils different types and subtypes, in the mosaicity of the soil cover: at a distance of several meters one can observe complexes of chestnut, light chestnut solonetsous soils and solonetzes.
The complexity and alkalinity of semi-desert soils prevent the development of these provinces for agriculture. Agriculture without irrigation on these soils is impossible (excluding light chestnut sandy loamy and dark-colored soils of depressions and estuaries, water regime which is more favorable). Basically, semi-deserts are used as pastures for local and distant pastures.

Desert soil cover

The soil cover of the deserts of the CIS is mainly represented by automorphic gray-brown soils and gray soils, and in places where groundwater is close to meadow-gray soils, solonchaks and takyrs. The total area of desert soils is about 8% of the territory of the CIS.
The main massifs of serozems gravitate towards the foothill loss plains of Central Asia with their mild, unstable winters, hot and dry summers, with a predominance of ephemers, ephemeroids, saltworts, and desert shrubs in the sparse vegetation cover. A. N. Rozanov considers serozem soils of subtropical semi-deserts.
Gray-brown soils rich in gypsum are confined mainly to the northern provinces of the deserts. They are most often distributed on the tertiary plateaus of Ustyurt and Betpak-Dala, where wormwood, saltwort, and ephemera predominate in the vegetation cover. Gray-brown soils and most gray soils are the poorest soils in terms of humus reserves.
Takyrs, almost devoid of vegetation, develop in flat shallow depressions, the genesis of which is still unclear. Of the other soils, the most widespread in the deserts of the CIS are solonchaks, rich in readily soluble salts, predominantly of sulfate-chloride and chloride types of salt accumulation. (Kovda, 1946, 1947). The possibility of removal of salts formed here and brought from outside is very limited. However, in the gray soils of the southern deserts, easily soluble salts in in large numbers occur no closer than 1.52 m from the soil surface, which is due to the fallout of most of the precipitation in the cold season, when evaporation is low, and soil wetting is deep enough.
Finally, in irrigated oases, cultivated serozems are formed, enriched with sediments of irrigation water. Serozems are quite fertile if they are irrigated and fertilized. Due to the low content of humus in desert soils, the introduction of nitrogen is very effective.