Control of Blown Sand Disasters

8/3/2019 Control of Blown Sand Disasters

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MINISTRY OF EDUCATION AND

SCIENCE OF KAZAKHSTAN

1 Kazakh-Turkish high school for gifted boysShymkent

SCIENTIFIC NAME OF THE PROJECT:

CONTROL OF BLOWN SAND DISASTERS IN KAZAKHSTAN

Section: Ecology

Done by: Alimbekov Tohtar

Yskakov Abilkhair

Leader: Teacher of Biology of the Kazakh-

Turkish high school HalilDemiroren

Scientific consultants:

Doctor of Agriculture Sciences,

professor Amir Seytkarimov

Candidate of Biology Sciences,

senior lecturer Rabiga Shamekenova


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Shymkent 2010

THE ABSTRACT

On a theme: CONTROL OF BLOWN SAND DISASTERS IN

KAZAKHSTAN

Shymmkent, 2010

Contents

1. Introduction

2. The literature review1.Experience of the Local People in Controlling Blown Sand Disasters

2.Comprehensive System for Blown Sand Control on the Oases

3.Comprehensive control measures for Tackling Vast Stretches of

Winderoded and Drift Sand Land in the Agricultural District of the Oasis.

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IntroductionPREVENTIVE MEASURES

Through their production practice over the years, the people in Kazakhstan

have gained rich experience in combating sand disasters, which has laid a solid

foundation for the working out of comprehensive preventive measures by scientific

and technological institutions.

As early as the 1960s, an experimental station of sand control was set up in

Shymkent by the Sand Research Team of the Kazakh Academy of Sciences. In the1970s, another research station was set up in Shymkent by the Agricultural

Scientific Centre of south-western Kazakhstan with a view to bringing under

control the vast stretches of wind-eroded drift sand land there. Also joining in the

research work on this area were the Academy of Forestry of Kazakhstan, the

Shymkent Institute of Desert Research of the Kazakh Academy of Sciences, and

the forestry research units of two counties and one municipality of Shymkent

prefecture. Working in close cooperation, scientists and the local people have

conducted investigations, studies ad experiments at fixed spots, and succeeded in

working out a wide range of measures for preventing blown sand disasters inKazakhstan.

The literature review

1. Experience of the Local People in Controlling Blown Sand Disasters

(1)Agro-technological measures

These measures are as follows:

1) Irrigating the farmland grown with desert crops before the wind comes.

This measure is usually adopted for use in farmland where the soil is very

sandy and lacks protection. This is because dry sand soil is more easilysubjected to wind erosion than wet soil, and also because water will

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prevent crops from being dried up by winds by adding to the humidity of

soil.

2) Heaping soil over the roots of cotton seedlings in their windward. When

cotton seedlings have broken through the soil, an earth bank, 10 cm in

height, is heaped up in the windward. The bank can protect the youngseedlings against strong winds of Force 8.

3) Planting cotton on ditches. On the farmland prepared for sowing ditches

are dug, in which cotton seeds are shown. These ditches are about

8-12 cm in depth. The seedlings can be protected in the ditches when

strong wind springs up.

4) Planting hemp on the borders of fields. Hemp has tall stalks and grows

fast. When planted on the windward border of a field, it can serve as aliving sand shield.

5) Deep ploughing on the open ground bordering on the farmland. On the

open ground close to field of loam soil, deep furrows are ploughed,

parallel to the field, to the field, to increase the roughness of the soil. This

measure can prevent drift sand from moving into the farmland when

there is a wind of moderate speed. However, it must be adopted with

caution, for the soil, thus roughened, will be easily eroded by the windwhen it is strong.

6) Postponing intertill and the thinning of seedlings. Both intertill and

seedlings thinning will loosen the soil, thus making it possible for sand to

be produced on the spot to harm the seedlings during the windy season.

By postponing the two processes, the windy season can be avoided.

7) Sowing melon seeds in furrows parallel to the wind direction. Melon

seedlings are liable to be damaged by sand. If the seeds are sown on theedges of furrows parallel to the wind direction, the seedlings on the

leeward section will survive even if those in the windward section are

damaged. Furthermore, if several seedlings are planted in one hole, they

will have an added strength in opcing with the wind.

8) Interplanting sorghum and cotton. It is usual practice in Kazakhstan to

plant wheat, cotton and melons first, and to plant sorghum and sesame

after the wheat is gathered in. However, if wheat and sorghum are

interplanted, the sorghum, which has a tall stalk and a better ability to

resist wind, will give protection to the cotton against drift sand.

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9) Using sand-resisting varieties. Wheat and sorghum are planted in the

frontal part of the farmland subjected to sand disasters instead of cotton,

because improved varieties of wheat and sorghum having a better

resistance to stand are available. This will reduce possible losses and

increase the relative yields.

The above measures were in wide use before the construction of protective

systems in the agricultural districts in Kazakhstan. However, with the

completion and have been falling in importance. Today, they are still being

used by a few peasant households living on the wind line.

(2) Mechanical measures for keeping off the sand

The adoption of these measures to fix sand and cope with blown sand

disasters has a long history in Kazakhstan. Chief among these measures are:1) Building mud walls to keep off sand. This measure was first introduced

in Shymkent, and is still in wide use there, as can be evidenced by the

presence of numerous such walls on the oasis. These walls are usually

2-2.5 m high, built at a right angle with the direction of the wind; they

are of different lengths which are determined by the scope of protection

they are expected to provide. These walls, allowing no passage of winds,

can effectively keep off the sand as well as the wind. As is usually the

case, a wall of a height of 2-5 m will give effective protection to an area

of a length of 40-50 m behind it. However, such walls take a lot of labour

and costs to construct. Besides, the offer no permanent solution, for they

will be buried in sand or topple as a result of wind erosion on the course

of time.

2) Placing a single row or rows of mechanical devices to keep off the sand.

This measure is usually adopted in an area on the wind line or at the wind

gap where the sand supply is ample and the winds are strong. Thedevices are made up of reeds, tree twigs, wild bush, and stalks of

sorghum and cotton. They are placed in a single row about 20 m from the

young forests, or in rows 20 m apart from each other. They are generally

1-2 m in height, and 20-30 cm in width, of a structure which is more

densely constructed in the lower part than in the upper part. These

devices can protect the young forests by fixing the sand or keeping it off.

3) Installing latticed mechanical devices to keep off the sand. Devices of

this kind can effectively fix drift sand, heighten the water content of

sandy land and speed up the growth of grass. They come in two

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categories. One is small interstices, 2 m x 2 m. A device of this type is

made up of sorghum and cotton stalks and Alhagi sparsifolia, having a

total height of 40 cm, and half of it is buried in the ground; the other is of

large interstices, 10m x 10m. Such a device is made up of sorghum

stalks, reeds and tree branches, so constructed that it goes 40 cm into the

ground and stands above the ground et a height of 1 m. As the

construction of these devices needs a lot of material and labour, they are

not in wide use in Kazakhstan.

4) Using earth lumps of grass bunches to protect melon seedlings, and

paving herbs on as windward side of irrigation canals to prevent wind

erosion. These measures, also classified as agrotechnological measures,

are chiefly the following: on the windward of melon seedlings are heaped

earth lumps, or are buried bunches of kind of grass(Sophoraalopecuroides, a plant mainly used as green manure for melons),

which can give fairly good protection to the seedlings when a Force 8-10

wind blows. Local herbal plants, such as Alhagi sparsifolia and

Scorzonera ramosa, are used to pave the windward side of an irrigation

ditch to protect it against wind erosion. This is because such a ditch in the

sand areas, usually built of sandy soil, do not hold water well once they

are eroded by winds.

(3) Closing sand areas to facilitate the growth of grass or channeling water to

irrigate sand areas to restore vegetation.

These are important measures effectively adopted by people in Kazakhstan in

combating sand disasters.

1) Closing sand areas to facilitate the growth of grass. This measure is

adopted for use in areas on oasis fringes where vegetation has been

destroyed. The so-called closing sand areas means closing these areas

to livestock grazing and feul gathering to facilitate the restoration of

vegetation. To ensure the success of this measure, a pledge is concluded

by people living in such areas, and special guards are assigned to see to

the execution of the pledge. The closing may be unconditional or

flexible, as is called for by the actual conditions of the vegetation. Theunconditional closing is applied to areas seriously damaged or with low

vegetation coverage. Usually, after many years unconditional closing, the

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vegetation can be in the main restored. In areas where sand dunes have

been successfully fixed, livestock may be allowed to graze on a rotation

basis, or people may be allowed to cut perennial herbal plants such as

Alhiga sparsifolia on a rotation basis so as to meet their needs for forage

grass.

2) Irrigation sand areas to facilitate the multiplication of grass. As it

happens, there is a surplus of water in winter in Kazakhstan. Such water

is channeled into sandy wasteland so that the plant seeds it carries will

grow into grass in due course. Another practice is to sow seeds of desert

plants on sandy wasteland after it is duly prepared and ploughed, and then

to irrigate it with winter water. By restoring the vegetation and increasing

the land-surface roughness, wind erosion can be reduced, sand production

or drift sand fixed.

(4)Afforestation

In Kazakhstan where blown sand disasters are serious and the temperature ishigh in summer, afforestation has become a tradition. People there plant trees

around their houses; grapes, mulberry and apricot trees in their gardens or

courtyards; willows along irrigation ditches and ponds ; and shelter belts in the

farmland. They do all the work on their own-selecting seeds, grown seedlings

and planting trees. Shelterbelts built in the basin fall in the following

categories:

1) Shelterbelts for protecting the farmland. As Kazakhstan has a large

land gradient, narrow shelterbelts planted to form a small network are

preferred. This is because such shelterbelts, while giving good

protection to crops, occupy just a small amount of land. In an area

where water supply is abundant, the shelterbelt is made to consist

chiefly of Populus alba var pyramidalis, flanked by a row of Murus

spp. or Prunus americana. In an area where water supply is scantly,

drought-enduring trees such as Ulmus spp. are planted. In an area

where the soil has a high salinity and alkalinity, Elaeagnus spp. is

chosen as the dominant species. In an area where the groundwater

table is high, Salix are adopted. Such a shelterbelt is usually

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composed of 4-5 rows, and the trees in a row are 1-1.5m apart. The

distance between principal shelterbelts is 200m or so in most cases.

2) Shelterbelts to keep off the sand. Shelterbelts planted in the forward

areas confronting the sand, each consisting 10 rows or so of trees, can

effectively prevent drift sand from moving into the farmland. Inplaces with poor irrigation facilities, it is the usual practice to plant

Tamarix spp., Elaeagnus spp. or Ulmus spp. or a mixture of them; in

places with good irrigation facilities, Populus alba var Pyramidalis

and Morus spp. are planted, usually in ditches a practice which

serves a double purpose of facilitating irrigation and washing away

the sand.

3) Shelterbelts to protect ditches and ponds. Trees are planted densely

along ditches and around ponds to prevent them from being buried in

sand. Trees selected for this purpose are mostly Salix L.

(5) Using water to wash sand away, and removing sand to create farmland

Sand accumulated in Kazakhstan is an indispensable material for sanddisasters. It often poses a threat to the farmland. Therefore, it is the customary

practice among the local people to use the water made surplus in winter by the

suspension of agricultural production to wash away the sand accumulation.

This practice not only gives added water content to the sandy land so that the

growth of shelterbelts and other can be promoted, but also makes it possible to

create new farmland and to improve soil quality.

1) Using water to wash sand away, and removing sand to create

farmland. In winter, water is collected from karizes to wash away

sand in areas with a certain slope. Usually, two able-bodied persons

can handle three karizes to wash 350 tons of sand in one night.

After such washing, the land is prepared without delay so that it can

be used for planting shelterbelts or turned into fields or orchards. The

sand can also be removed by manpower to be mixed with the clayey

soil of certain fields to improve its soil quality. A good example is theoasis in Kyzylorda of Kazakhstan Municipality, where very

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remarkable results have been achieved by treating the mobile sand

dunes there in this summer.

2) Using water to wash away sand on roads, in ditches and shelterbelts.

In the course of land irrigation in the oases, water is also used to wash

away the sand accumulated on roads, in ditches and shelterbelts. Thispractice can ensure the smooth flow of traffic as well as the normal

operation of peasants. It is usually applied in areas with a slope and

without much sand accumulation.

(6)Transforming the Gobi

The zone of gravel Gobi is an important source of sand supply for blown

sand disasters in the Basin. Therefore, if the Gobi is turned into an oasis, sand

supply will be reduced and the area of cultivation enlarged. To achieve this,

what the local people do is make use of the slack seasons and their spare time

in farming to dig, in areas of the Gobi where water supply is ensured, ditches

which are 7-10 m apart, 0.5 m deep, 0.5 m wide at the bottom and 1.5 m wide

at the top. Then they dig, at in interval of 2 m on the bottom of ditch, pits

which are 0.5 m deep and wide. These deep ditches, while protecting the vinesagainst strong winds up to the time they bear fruit (5 years), will greatly reduce

blown sand, or bring it under effective control.

2. Comprehensive System for Blown Sand Control on the Oases

In their long practice in combating sand disasters, the people of

Kyzylorda of Kazakhstan Municipality have been able to develop gradually

a complete protective system suited to the local conditions. To sum up this

experience, a joint investigation has been conducted by the agricultural

scientific centre of south-western Kazakhstan. Through the investigations, it

has been established that the protective system is a comprehensive one

consisting of three components. Outermost is the zone on the border of the

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oasis, sand and wind; innermost is a network of shelterbelts crisscrossing the

farmland (Fig. 1). The three components, working in conjunction with one

another, and by combining sand control with sand prevention, successively

reduce the force of drift sand as it moves inward. This kind of system is,

therefore defined as suitable for use in areas on the oasis suffering from

serious blown sand disasters.

(1) The outermost zone of the oasis closing off sand for growing grass

This zone, 300-500 m in width, lies on the forward part oh the oasis

where the land surface is loosened as a result of serious wind erosion andwind sedimentation. Closed to livestock grazing and feul gathering are

forbidden to protect the natural vegetation, and at the same time, the land is

irrigated in winter to facilitate the growth of grass to enlarge the vegetation

coverage. As investigations show, winter irrigation can increase the water

content of the soil and promote the natural tillering of prammophilous and

xerophilous plants. On the average, there is an increase of 7 seedlings on

one m of sandy land, and in 3 years time, the vegetation coverage can go

up to 60%. Once the vegetation coverage of the whole zone exceeds 60%livestock grassing and feul gathering can be allowed, first in one part and

then in another, so as to increase the ecological economic benefits.

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(2) Tall shelterbelts on the oasis border

These shelterbelts are supposed to play the role of reducing the speed of the

wind that has crossed over the protective zone, and of keeping off and bringing

down the sand it carries so as to reduce the blown sand flow damages. Based on

this principle, the shelterbelts in Kyzylorda of Kazakhstan Municipality show a

number of strong points such as afforestation with ditch construction, alternation of

wide shelterbelts with narrow ones, and multi-line deployment. In Kyzylorda, the

shelterbelts are made to extend along the contour line of the oasis border. Before

the afforestation, ditches are dug, which are 1.5 m wide, and 4.5 m apart form eachother. This arrangement has many good points on the one hand, water can be

saved when the land is irritated for afforestation, and alkaline and saline damages

can be prevented; on the other hand, water in the ditches can be used to wash away

the accumulated sand. It is the usual practice there to plant two rows of Elaeagnus

spp. on the edges of the first ditch because such trees can withstand the wind, even

when they are young, and can give greater compactness to the shelterbelt. Inside

the shelterbelts, there are two sublateral canals. On the windward of one canal, a

row of Populus alba var Pyramidalis are planted; on the windward of the other, arow of Ulmus pumila are planted. On the leeward of two canals, a row of Populus

alba var Pyramidalis and a row of Morus spp. are planted respectively. This kind of

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deployment, characterized by an alternation of long-living with fast-growing

species, and tall with low species, provides structural stability to the shelterbelt

zone , and increases the roughness of the shelterbelt canopy to make the zone

better able to weaken the force of the air flow.

(3)Central link of the system farmland-protecting network of shelterbelts.

The network is aimed at further reducing the wind speed to create a more

favourable microclimate for the growth of crops, and also at preventing sand

production in fields whose surface has been destroyed by ploughing. This explains

why the network is the key component of the whole comprehensive protective

system.

The trees suitable for use in the network include Ulmus aumila, Populas albavar Pyramidalis, Morus spp., Elaeagnus spp., America valgaris, etc., all of which

have a strong ability to resist bending. The shelterbelt is a composite one, narrow

and sparsely structured. The key species in such a shelterbelt are Ulmus pumila

and Populus alba var Pyramidalis, which, being tall, fast-growing and of a long

length of life, can provide the shelterbelt with the necessary height and long-lasting

effectiveness in protecting the farmland. On the windward side of the shelterbelt

are planted Elaeagnus spp., which, with their thick foliage, can protect the

farmland as bushes when young, and, when ripe, can make the key species to grow

straight by providing shade at the side. On the leeward of the shelterbelt are

planted Morus spp. and America valgaris, which can increase the width of the

shelterbelt canopy and bring in economic benefits by yielding fruit.

The shelterbelt is 6-12 m wide, consisting of 4-8 rows of trees. The distance

between rows is 1.5 m, and that between trees is 1-1.5 m. The principal shelterbelts

are usually 200-250 m apart from each other; the whole network, which is small,

measures less than 14 hectares.

The above is a general survey of the comprehensive protective system made

up of various components. With the completion of such a system, not only can

blown sand disasters be brought under control, the man-created ecological system

of the desert oasis can also be stabilized.

3. Comprehensive control measures for Tackling Vast Stretches of

Winderoded and Drift Sand Land in the Agricultural District of the Oasis.

Lying in the agricultural district in the heartland of the basin is the wind-

eroded and drift sand land devoid of any vegetation, which can not possibly dealt

with by simply building a comprehensive protective system as described above.

This is because such land is large in area and rich in sand supply. Situated on theprincipal wind line in the basin, it is subjected to the attack of very vigorous sand

flows; being devoid of vegetation, it can hardly be irrigated in winter to promote

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the growth of grass. In 1973, an effort was made to irrigate the level part of the

land in winter and to plant on it sand-fixing plants. However, all the seeds sown

failed to emerge and natural grass also failed to grow. Nor did the attempt to build

a shelterbelt of bending-resistant arbores such as Ulmus pumila and Elaeagnus spp.

meet with any success. In 1975, a 3000 m-long shelterbelt consisting of 20000

trees was built in this area, but again it failed to survive except one single plant ofPopulus euphratica.

All these failures have driven home the importance of the fact that protective

measures taken should be suited to the local conditions and the characteristics of

the disasters. On the basis of this principle, a program has been formulated for the

overall control of the sand disasters, and a new protective system worked out

through experiments and research, which can work effectively under the peculiar

conditions of this area. The system retains the key component of the above-

mention system the network of shelterbelts for the protection of the oasis

farmland, but two more tree species are added Populus euphratica which enduressalinity and alkalinity, and Robinia pseudoacacia, which can improve the soil. The

other two components are both replaced by sand-fixing forests (Fig. 2). Following

is an account of the technical measures adopted to build such forests.

Fig. 2 Sketch map of shelterbelt system

(1)Selecting plant varieties good for sand-fixation

Bushes have been widely used both in China and abroad to fix or keep off

drift sand, increase the roughness of land surface, to reduce the force of blown-

sand flow and improve the microclimate. To apply this measure to Kazakhstan, the

most important thing to do is to select varieties which can withstand high

temperature and drought, and survive even when buried in sand. In the basin,

nearly 20 species have been introduced for trial planting. Out of the twenty, 9 have

been selected (Table 1), all of which feature a high utilization value and a good

ability to withstand drought, to resist wind erosion and to fix sand.

(2)Water supply for sand-fixing afforestation

Water supply is crucial to the survival of plants growing on winderoded and

drift sand land. It is one of the important factors to be taken into account when

trees are planted to fix the sand. In this area, the groundwater table is about 10 m;

the layer of earth 2-3 m below the surface cannot provide effective water supply toplants as it is extremely dry for lack of water replenishment; the drift sand or sand

dunes spread on the wind-eroded land is dry, too, which the scanty precipation

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cannot make wet enough for the growth of plants. Such being the case, the only

possible solution is to collect water from karizes in winter and channel it to the

wind-eroded drift sand land for irrigation. Before such irrigation, land preparation

is necessary. On level and slightly undulating sandy land, ridge-bordered plots are

built, manually or by mechanical means, to divide into rectangular pieces, each 5-6

m wide, aligned along the contour line. In the case of hard wind-eroded land anddrift sand land with great undulation, the usual practice is to use a bulldozer to

push earth together to build water-retaining banks in accordance with the terrain so

that reservoirs of different sizes can be formed in the course of winter irrigation;

another method is to dig ditches, into which water is supplied. In the case of

interdune lowland and deep wind-eroded pits, irrigation is done by supplying water

directly into them. The amount of water needed for irrigation is about 1500-300 m

per ha. In the year following the winter irrigation, the biggest change in water

content takes place in the 0-40 cm earth layer of drift sand land, and the 0-40 cm

earth layer of wind-eroded land - both have a higher humidity in spring. Humidityof the earth below the above-mentioned sandy earth layers is relatively stable, with

water content standing at 3-5% in the case of sandy land, and 10-18% in the case

of wind-eroded land (Table 2). A survey has been conducted to determine the

wilting humidity of plants on sandy and wind-eroded land. As shown by the results

of the survey, in the case of sandy land, the wilting humidity is 1.56% for C. caput-

medusac; in the case of wind-eroded land, it is 6.80% for Haloxylon

ammodendron, and 6.72% for C. caput-medusac. If these figures are compares

with the water content of wind-eroded and drift sand land irrigated in winter, it can

be seen that such land can effectively provide water sufficient for use by the sand-

fixing arbores there.

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Process of desertation

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Calligonum- Apyllum

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C. Caput-Medusac

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Holoxylon ammodendron

Calligonum

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Control of Blown Sand Disasters

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