CLIMATIC FEATURES OF GEOKDEPE AND
Institute of Deserts, Flora and Fauna
The climate of Geokdepe and Bayram-Aly regions has sharp continental character. Average annual temperature of air makes 14,8-16,400С. Per winter months the monthly average temperature of air from north to the south makes from -2,0 +0,50С up to +0,9 +4,30С. In the most hot summer period the monthly average temperature of air reaches 30,6-32,30С. The absolute minimum of temperature makes minus 26-300С, and the absolute maximum of temperature makes 46-48 0С (Table 1).
The spring (the stable transition of average daily temperature of air through +50С) comes in the third decade of February. The average dates in last spring frost from the south to north are shifted from March 15 to March 26. The first autumn frost, on the contrary, in north are observed on October 31, and in the south on November 4. The average duration of non-frosty period makes 220-230 days.
The maximal heating of a surface of soil per summer months reaches 71-730С, and per winter months 32-400С. The average monthly temperature of a surface of soil in winter time differs from temperature of air slightly (-1 +4 0С), per summer months temperature of a surface of soil on 6-7 0С is higher, than temperature of air.
The quantity of atmospheric precipitation in different points of Geokdepe and Bayram-Aly regions for one year makes 128-236 mm. The basic part of atmospheric precipitates drops out for a cold season (XI-III), Table 2. In the summer period (VI-IX) atmospheric precipitates do not drop out almost. Therefore maximal stocks of a moisture in a layer of soil 0-100 cm are observed per spring months - March - April.
Cause of small amount of dropping out atmospheric precipitation, and small amount of heat spent on their evaporation, the basic part of radiating balance is spent for heating of soil and air (1,2). This is the basic reason that in this area the very high temperatures of air and soil are observed. Because of a small disproportion of heat and moisture the conditions of growing of pasturable plants are considerably worsened. All vital processes of deserted plants took place in severe climatic conditions. The favorable climatic conditions for development of plants are almost excluded here, as annually plants are oppressed either from shortage of a moisture in soil, or from high temperatures of soil and air. Therefore each vital form of plants has adapted to conditions of an environment by own way, which was the reason of formation of their various biological features.
So, occurrence of ascents or the renewal of vegetation of spring grassy plants is observed depending on weather conditions in autumn, winter or early spring, and finishes vegetation at the end of April and in the beginning of May.
The vegetation of bushes and subshrubs usually begins in the spring, sometimes in autumn. However, at autumn renewal of vegetation the fresh branches, as a rule, are damaged by winter frosts or autumn frosts. The intensive growth of these plants occurs in May and June, fructification at the majority of them is removed to autumn. The degree of fructification also is closely connected to conditions of weather during the vegetation period, but this
question is still not well investigated. The growth and development of bushes and subshrubs depends on stocks of a moisture accumulated for the autumn-winter period and from supplying by a moisture and heat in the spring-summer period. The influence of supplying by a moisture and heat of territory on development of bushes and subshrubs is especially brightly shown at ascents and young species of these plants. It can be explained by the oversoil and the undersoil ascents and young plants within the first years develop in the most lower, nearly earth layer of air and in the top layers of soil, where the greatest daily, monthly and, at last, seasonal fluctuations of meteorological elements (1,3,4,5,6) are observed. For this reason, within the first years of life the plants should overcome critical "barrier" of agriculture-meteorology conditions, determining opportunity of their further existence.
To correct analyzing of agriculture-meteorology conditions of growth and development of pasturable plants it is necessary to determine in the given areas three basic periods.
1. The autumn-winter period, during which the certain conditions of humidifying of soil giving an opportunity quantitatively are created to estimate at the end of the winter period depth of moistening of soil, stock of an accessible moisture in a meter layer of soil. If to the moment of approach of spring the depth of moistening of soil is insignificant, the plants will badly develop, as one only spring atmospheric precipitations can not humidify deep layers of soil. In the spring the significant part of the dropped out atmospheric precipitations are spent for evaporation from a surface of soil, the top layers of soil therefore are humidified only. Hence, the efficiency of spring atmospheric precipitations considerably raises in the event that for the autumn-winter period the depth of moistening of soil makes not less than 70-80 cm.
2. Spring period. In the spring the basic part of year norm of atmospheric precipitations drops out. If in the autumn-winter period and spring the amount of atmospheric precipitations was sufficient for development of plants, the favorable conditions for the accelerated development of pasturable plants are created. If the autumn-winter period was damp, and spring was droughty, then the top layers of soil are fast dried and the plants constantly develop in conditions of a drought. The precisely same picture is observed those years, when the droughty autumn-winter period and damp spring is marked.
3. In the summer period the plants are suffered from lack of a moisture and from high temperatures of air and soil. Within years, when the winter-spring periods are droughty, the grassy vegetation dries up in the beginning of April. Even those years, when the spring soil had deep humidified, in the summer the certain part of plants suffers because of lack of a moisture of soil.
Thus, in the given areas the favorable development of pasturable plants depends mainly on amount and distribution of atmospheric precipitation, and also their favorable combination to temperature conditions of the autumn-summer period.
The brief characteristic of natural
conditions of Bayram-Aly area.
Geographical situation and borders.
Bayram-Aly region was formed in 1925 and is situated in a northeast part of Mary District. Its territory adjoins to Garagum and Turkmengala regions. The investigated region is located between 370 14' and 38028' of east longitude.
The configuration of territory of region reminds a rectangular, which large extent is observed in a direction from northwest to southeast. Its maximal length from west to east makes about 150 km, average width is about 100 km.
The border of the region in north, northeast passes on border of Lebap District, in northwest with Garagum, in west with Mary and Murgap, in the south with Eloten and Turkmengala regions. The area of the region is 1763 thousand km2 with the population 107,6 thousand peoples.
The significant extension of territory of the region causes diversity of a landscape. The most part of the region occupy Garagums, namely parts of Low and Southeast Garagum. The border between them conditionally passes by rail. The West of region is partially consisted from oasis, which is wedged in sandy desert. The width of oasis zone does not exceed 40 km. The region is crossed by the river Garagum by extent of about 130 km. In investigated territory the following physical-geographical regions are defined: Lowest-Garagum region, Murgap oasis, South-east-Garagum.
In the region there are 2 settlements, 18 geneshliks and 53 villages occupied settlements. The basic directions of economy are cotton-growing, grain growing, vegetable-growing, gardening, animal industries, fish economy and silkworm stratuming.
Geological structure and relief
The researched region represents influenced by the wind alluvial plain formed in the first half of the Quaternary period by activity of pra-Amudarya and its left inflows, directing the water in the Caspian sea.
Feature of these parts of Garagum (east part of Central Garagum and all region of Southeast Garagum) is the wide extension continental neogenic sediments, which are exposed on the surface or are covered only by the low-power Quaternary cover. The sediment of neogenic age occupies the extensive region to east from Murgap, and are exposed to north from the railway in the region of the station Uchadjy.
The wide extension here of neogenic stratums gives the basis for the conclusion, that this part of Garagum has not undergone to appreciable lowerings in the Quaternary period.
However in neogenic period this territory undoubtedly was covered by lowerings, that is established by significant capacity of continental neogenic sediments, which reaches in the Lower Murgap and in the region of the station Uchadjy 300-400 m.
Among the Quaternary sediments most wide extension have alluvial sediments of Garagum chain generated at the expense of activity of pra-Amudarya. They are submitted by rather monotonous thickness of steel-gray
micaceous sands with related layers of yellow-gray and pale-yellow sand, and also loamy and clay layers.
The modern forms of the relief of sandy desert are obliged by the origin and development of aeolian processes. Dismembered surface of sandy desert changes over a wide range. In Central Garagum distinction in height between sandy ridges and downturn dividing make 10-15 m, in delta of Murgap 8-10 m. Under the forms the aeolian relief differ by ridge, ridge-hilly and barkhan sands. The first of them are characteristic for Central Garagum, and the second for Southeast Garagum. Such characteristic forms of a relief as takyrs and alkali soil meet in ancient delta of Murgap and in Southeast Garagum.
In total relief represents ridge sands with dividing them inter-ridge downturns. It is possible to allocate the following forms of relief.
Barkhan sands are distributed basically along a line of the channel. This form is formed mainly at the expense of work of mechanisms during construction of the channel and they are extended by a narrow strip along the channel.
The ridge-cellular sand are extended in parallel and meridionally, they are connected among themselves by crosspieces. Their relative heights change within the limits of 5-25 m. The cells are located in interridge depression. Their surface is covered by fine bumps. The diameters of the cells change within the limits of 30-150 m.
Flat-undulating sands are covered by fine bumps. These bumps are reached the height of 0,5-1,0 m. The sands are fixed and condensed.
The valley of the river Murgap is combined by the Quaternary sediments. The Alluvial sediments have 150 m of height. The forms of a relief are mainly connected to washing erosive activity of the river. In the investigated area there are former river-beds, peninsulas, which are waterlogged and salted.
The steadiest weather per cold half-year both rather steady hot and dry summer is typical for the climate of the region. It is explained by sharp distinction of synoptical processes: in the cold period of the year cyclone activity is advanced, summer by the basic atmospheric process becomes transformation of air weights above the strongly heated up sand of desert Garagum.
The average annual temperature in this territory is positive and makes 15-180С. The winters are soft and law- snowy with frosts of average and moderate force. The most cold month is January with average temperature +3,00С. Per separate years, with prevalence of cold intrusions, is especial at powerful development of the Siberian anticyclone, the winters differ by the special severity. The frosts are kept long time and reach -30 -360С.
The Summer is very hot and dry. Maximal temperature of air is observed in July. Monthly average temperature in July exceeds 300С. An absolute maximum is 48-500С.
The Spring is short with often changes of weather and returns of colds, at which quite often there are frosty days. The average dates of last frosts are observed for the second and third decade of March. The average dates of first autumn frosts are marked in the third decade of October. Duration of the not-frosty period makes 230-250 days.
Characteristic feature of a climate of Garagums are the large duration of solar light. On the average for one year it reaches 2800-3100 hours. The duration of solar light is closely connected with nebulosity. The average annual size of nebulosity is insignificant - 3-4 numbers. The least amount of clouds is observed in June - August, when the average degree of a covering of the sky by clouds is equal to one number. By winter nebulosity is increased and reaches the maximal meanings in January - 6-7 of numbers. The annual number of clear days are maximum 160-185 days. Number of cloudy days on common nebulosity on the average for one year 60-45.
Due to a southern situation and mode of nebulosity the territory of the river Garagum receives a plenty of solar radiation. The annual size of total radiation makes 163 ccal.
The Garagums concern to a zone of unsufficient humidifying. Features of atmospheric precipitation consists in their extremely small amount and non-uniform distribution during one year. On the average for one year 118-135 mm of atmospheric precipitations here drop out. The amount of atmospheric precipitations which are dropping out in the cold period, in 2-3 times is more, than in warm.
The high summer temperatures of air unsufficient amount of atmospheric precipitation and absence of superficial waters cause a mode of humidity of air. The greatest meanings the relative humidity reaches in January 70-78 %. Driest period are from June up to September, when monthly average humidity is lowered till 22-25 of %. The low humidity of air promotes intensive evaporation from a water surface: the annual size of evaporation reaches 2300 mm, that in tens time exceeds atmospheric precipitation for one year.
At sharp deficiency of atmospheric precipitation the droughts of various intensity and durations are marked. For Garagum the rather often droughts are characteristic, the probability of which occurrence makes here 50-75 %. The dependence on droughts of pasturable vegetation is more brightly expressed. Per droughty years the influence of droughts accelerates burning out of pasturable vegetation on 15-20 of days, and the productivity of pasturable vegetation is reduced on 30-65 of %. Average annual speed of a wind of 2,2 m. / sec, primary direction of a wind - northern.
Superficial and underground waters.
To superficial waters of Bayram-Aly region the river Murgap and the river Garagum concern. The river Garagum crosses hilly and ridge sands of Southeast Garagum on an extent more than 130 km. And near the settlement Zahmet leaves on soils ancient irrigation of Murgap oasis.
Region of pool of the river Murgap exceeds 60 thousand km2. The spring stretched high water is characteristic for a mode. The average long-term charge of water makes 50,4 m3/sec. In Bayram-Aly region enters western part of delta of the river Murgap.
On the most part of region the superficial drain practically is absent. Only on sites, where are available takyrs, the incidental local drain, but in conditions of desert having the large economic importance is formed.
Up to the construction of the river Garagum in the given region the ground waters had typical for Garagums character. With start-up of water on the channel the level of ground waters began to rise. Ground waters at the channel
are on depth of 4-5 m., and in parts, separate of the channel, ground waters are more deep. Depending on dismembered character of the relief their depth changes from 3,5 up to 20-40 m. The mineralization of ground waters changes within the limits of 0,5-13,0 g/l. In depressions the ground waters are on depth of 1,5-5 m.
The Ground waters of a valley of the river Murgap are formed at the expense of a filtration of waters of Murgap. The Depth of deposition of the ground waters various: from 6-8 m up to 15-20 m. The Mineralization of the ground waters are increased with removal from a valley. Mineralization of the ground waters on northern moonlit exceeds 15 g/l at depth of deposition of 10-20 m, and on southern monolits from 3-5 till 10-15 g/l at various depth of deposition, frequently reaching 200 m and more.
Here are distributed the sandy deserted soils. The soil formation processes of the sandy deserted soils are connected with long and intensive heating and drying of the surface in the dry summer-autumn period, which alternates with the damp winter-spring period. In the humidified time the soil formation processes proceed intensively and the organic substances are decomposed.
The deserted sandy soil develop under brushwoods of the black haloxylon. They differ by presence on the soil salted cover, which is formed at the expense of influence of ash elements contained in opade of runaways black haloxylon. The general contents of salts in this covers reaches 0,5 %, at the same time the common alkalinity makes about 0,2 %. The Covers formed under the black саксаул, interferes growing of psammitic vegetation.
Except for sandy deserted soils in this region the plaster alkali soils are distributed. These soils formations develop in flat depression surrounded with sandy ridges. The contents of plaster in takyr-kind covers of alkali soil plaster makes about 20 %.
At formation of a soil cover of a valley Murgap alongside with natural conditions the strong influence renders the anthropogenous factor. The soil-forming stratums in a valley of the river are ancient alluvial and modern alluvial of sediment. Their capacity reaches several ten meters.
In the Murgap oasis prevail easy, average and heavy mechanical structure of soil. The large distribution have received of soil with bad physical properties. Salinity of soils are not equal. There are available not salted, weak salinity, high salinity of soil and alkali soils.
Here there are following types of soils: permanent-meadow, meadow-deserted, meadow-alluvial, meadow marsh, alkali soils. From the specified types of soils most widespread are meadow-alluvial. These kinds of soil are combined basically with alluvial sediments, in mechanical structure the easy versions prevail. The contents of humus in these soils are slightly - about 0,5 %, sometimes its contents raises up to 2-3 %.
The vegetative cover of the given region had typical deserted character. The ecological conditions on a line of the channel have begun from time of start-up of water of the river Garagum to change, therefore flora of the given region
became more various. With arrival of water the conditions for local deserted plants changed, the structure of vegetation has undergone some changes in a narrow strip of the channel. Here on a coast of the channel and on coast of filtration lakes the plants, new to this region have appeared: reed, reed mace, tamarisk, ak-bash etc.
With removal from the channel on 0,5-1,5 km the zone of filtration of lakes comes to an end and begins peculiar for Garagum vegetative cover. The character of a vegetative cover is connected to a relief of sand. On barkhan sand grow aristida and suxen at the condensed tops of ridges of white haloxylon and cherkez; on the lowered sites, where ground waters are close is distributed black haloxylon. From grassy plants are typical ilak, epelek (Anisantra tectorum), camomile (Matricaria lamelata), poppy (Papaver pavonilum), couch-grass (Agropyrum bionapartis), Malcolm (Malcomia grandiflora) etc.
In the given region the following vegetative associations are allocated:
1. Erkek-aristidas on the broken sand along the channel.
2. Artificial cherkeznik on dams of the channel. In plantings of cherkez of Paletskiy there are following kinds of grassy plants: Саrех physodes, Eromopurum feronapartis, Senecio subdentatus, Papaver pavonilum etc.
3. Tamarisk with a reed and akbash on the lake sand. This association occupates the coastal filtration lakes.
4. Kandym-white haloxylon cherkeznik with ilak on ridge cellular sand along the line of the channel. This association occupies a zone of filtrationон lakes.
5. The white ilak ridge-cellular sand. Cherkez and candym meet in an impurity in insignificant amount.
6. The mixed Haloxylon, cereals on sand in depressions.
7. Cherkez haloxylon at participation of ilak at tops of ridges. On number of bushes in this association prevails cherkez.
8. Blackhaloxylon with cherkez on a ridge-cellular sand. The bushes of black haloxylon reach the large sizes in cells and on slopes, forming rich brushwoods.
9. Candym-white haloxylon and ilak ridge-cellular sand. In this association candym and white haloxylon participate almost in equal
10. Bordjok whitehaloxylon with candym and ilak on sand,
bedding to gypsum depressions. This association occupies Cellular sand. In structure prevail Bordjok, white haloxylon, candym.
11. Blackhaloxylon on the plain-hilly gypsum sand. Blackhaloxylon occupies rather large depression, which are surrounded from different directions with cellular sands. In a cover there are deserted glue (Tortula desertorum).
12. Blackhaloxylon ilak on depression sands. The bushes of black haloxylon reach the large sizes (height 5-6 m).
13. Cherkez-candym whitehaloxylon cereals on the small cell sands. The grassy cover is presented by arpagan (Eremopymm buonopartis), epelek, ilak etc.
14. The vegetation of a valley of the river Murgap by a radical image differs from a deserted part. Here basically are distributed water-resistant plants and vegetation. Owing to development of soils of a valley Murgap under irrigation agriculture the natural tugays were over meet only in a narrow strip of a valley. Basically it consists of poplars: Populus divesifolia, poplar grey (Populus prinosa), and also loeaster narrow-leaved (Eleagnus angistifilia), tamarisk (Tamarix sp) and high-grassy plants: Cane (Phragmites communis), khysh (Erianthus ravaennae), malt (Clycyyrrhira glabra) etc.
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