Annals of Arid Zone-17 (1), 92-98, J 978

Role of biotic and environmental factors in theextension of the Lut desert in Iran

PARVIZ KARDAVANI

The Arid Zone Research Centre of Iran,University of Tehran, Tehran (Iran)

ABSTRACT

The Lut Desert is situated in the south-eastern part of Jranand extends over about 80,000 sq km. The desert is surrounded byregions of higher altitudes.

The Central Lut is the most extensive and also the lowest areaof the Lut Desert. The principal characteristics of this desert areas follows:

Jt is extremely poor in vegetatioo. The ceotral part of CentralLut has no vegeta tion at all.

Jt is also poor from the water point of view. The only per-manent river of the plain is "Saline Birjand River".

The region has a very dry climate, the average annual rain-fall being no more than 60 mm. The central parts of this desertmay have no rains even for years. The relative humidity is verylow in summer, sometimes less than 10%.

The extension of the Lut Desert has been caused especiallydue to wind effect, besides other natural factors.

Although the number of people living on the margins of Lutis very small, they play an important role in the advancement ofthis desert.

Natural Characteristics of the Lut Desert

a. Limits and Extent: The Lut Desert is situated in the south-eastern.part of Iran between about 57° 33' and 60°£ and also between 29° and 32° ]5'N(Mahmudi, 1970). It covers about 80,000 sq km.

b. Topography: Because of the mountains surrounding it and therocky outcrops at certain places within the desert, two particularly uneven

.1EXPANSION OF IRANIAN LVT DESERT 93

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regions can be distinguished in this area (Kardavani, 197.); Mahmudi, 1970),One is the vast and relatively even Central region, the other is the regionof the foothilL,. The central part i<; the most extensive and also the lowestarea of the plain. It may be considered to be a representative geographicalunit of this desert as it has several characteristic desertic features like sanddunes, "Hamada" etc.

c. Soils (Kardavani, J 970, 1971, 1975): Various types of Zonal( brown and grey etc.), Interzonal and Azonal soils occur in the Lut plain.Some soils exhibit electrical conductivity of more than 500 mmhos/cm. The soilsare usually neutral, although some may be alkaline in nature

d. Water (Mahmudi, 1970): The only perennial river in the plain isthe Birjand River, which enters the Lut from the North and ends in the centralpit of the plain. Its water is very saline, and the salinity increases as it getsnearer to the central depression.

e. Vegetation (Dresch, 1971; Kardavani, 1970, 1971; Monod, 1971);This plain is much poor in vegetation, than the Central Kavir. The northernborder of the Lut is comparatively rich in vegetation. In the Central Lut, onlythe eastern and western borders have some vegetation. Two thirds of the sandhills, "Rigs", located in the eastern Lut, have some vegetation (Haloxylon).

The southern Lut of "Lute-Zangi-Ahmad" is richer in vegetation thanthe Central Lut. Different plant types OCcur in different parts of the Lut.The following plants are dominant: Haloxylon mult(florum, Seidlitsia rosmarinlls,Tamarix stricta.

f. Climate (Huckride, 1971; Kardavani, 1975): Ganji (1974) hasidentified the climatic type of Lut plain as desertic. There is no summer rain.The average rainfall around the Lut plain is less than 60 mm per year. Theavenge relative hun~idity in winter is less than 40 per cent.

Generally, the temperature is the highest in August and lowest inJanuary, the difference between the two extremes being very high. The aVerDg~minimum temperature recorded in Bam is -7.5°C and the average maximum,44.5°C, while its 12 yearly average is 22.1°C. The maximum, temperature everreported from Bam (altitude 1055 m) was 450C.

The wind direction is north-eastern in summer and southern in latewinter and early spring. These winds decrease the effect of the rain andincrease the effect of the heat in this regIOn.

EXPANSION OF IRANIAN LUT DESERT : 95

The -inhabitants' of the Marginal Lut· and their means of livelihood(Fesharaki, 1970; Mostoun, 1972; Mohajerani. 1970)

Since living conditions are more favourable in the margins of Lut thanin its central part, people have lived there for ages and still live there. Theoccupations of the inhabitants of the Lut are agriculture, animal husbandry andcarpet weaving.

In the interior of the Lut, there is only one village, called ShahrokhAbad, situated at the Southern Lut in a non-saline alluvial land. Theinhabitants of the northern Lut are not in direct contact with the more difficllltparts of the Lut desert, as the inhabitants of the eastern and westernregions are.

Of all regions in the Lut desert, the southern margin is the mostdensely populated, because of the better quality of the soil and easy accessibilityto sweet water. The western margin comes next in population density. Themost important villages of the region, which are directly located at the edgeof the desert, are the villages of Shahdad, which, together with Shahdad itself,have a population of 3,790 (1966 census). The eastern margin has the thinnestpopulation. lhis small number of inhabitants keep sevenl herds of sheep andtake care of thousands of camels. In this way, and also by getting firewoodfrom the shrubs in the desert, they earn their livelihood.

The remnants of old buildings, ruins of huge castles, traces of vastcultivated lands etc., all indicate that in the past, more areas of the Lut marginswere populated. Probably, both man and natural factors have been instrumentalin making life conditions unbearable in this region.

Expansion of the Lut desert

.The advancement of the Lut Desert which is quite evident in all themarginal regions, can be particularly traced to the following causes:

1. Destruction of the vegetation; 2. severe land erosion; 3. blowing ofsands, and 4. extension of the, sand dunes, leading to the destruction of theGanat irrigation system and farms or inhabited regions.

In the expansion of the Lut Desert, two kinds of factors, human andunfavourable natural factors, have been at work.

A. Human Factors (Kardavani, 1971; Mostoufi, 1972): Man has beendirectly or indirectly involved in the advancement of the Lut desert through:

96 PARVIZ KARDAVANI

(a) Destruction· of Vegetation by: 1. Eradicating bushes, trees andshrubs and using them as firewood or as construction materials or as forage forcattle. 2. Making charcoal out of the logs and trunks of various plants.3. Continuous and excessive grazing of cattlt>.

Traces and remnants of vegetation show that the vegetation of themarginal Lut has vanished over a vast area in all directions.

(b) Salinization due to irrigation by saline water and lack of thesoil salinity

In the margins of the Lut, especially in its eastern and western margins,one can see the remnants of some ancient citadels, which in former times hadenjoyed great significance and there had been considerable amount of cultivatedland in their neighbourhood. Today these lands lie waste and useless. Salinecrusts have appeared on the land surface leading to deterioration of the land.

B. The effects of unfavourable natural factors (Coque, 1971; Dresch,1971; Mahmudi, 1970).

a. The disappearance of the vegetation due to un favourable naturalconditions, and the increase in salinization of the land as a result of thedryness of the climate and severe evaporation.

Historical accounts and physical evidences indicate that the Lut Deserthad a more humid climate in the past (Huckride, 1971).

b. Salinization of the soil and the expanse of the wasteland surfacedue to the flowing of saline water in the margins and the interior of the Lut.

c. The strong winds play an important role in the desertification ofthe land. Erosion of the land, covering and submerging the surface of theorchards and the cultivable soil and filling up of the wells and Ganat channelsand destruction of the houses by sands, are among the un favourable effects ofthe wind currents, which one can easily observe in various regions of the Lut.This undesirable action of the wind has wrought havoc on the farms andvillages lying in the margin of the Lut Desert.

d. In the Lut Desert, land is not eroded by the wind alone, but watertoo is one of the main agents in the severe er0sion of the soil.

EXPANSION OF IRANIAN LUT DESERT 97

Possibility of Dedesertification of the Lut Desert

Some of the steps which may prove useful in dedesertitication areas follows :

1. Control of the occurrence and/or force of the sand storms

2. Reduction in the number of cattle and camels to a reasonablenumber

3. Prevention of the disproportionate and' imbalanced utilizationof the vegetation, .especially for tirewood, forage, etc.

4. Pr~vention of salinization of waters, and the flowing of thesaline waters, in the margins of the Lut Desert, as faras possible.

5. Creation of a green girdle of vegetation as rar as possible.

REFERENCES

Coque, Rager 1971. A report about the Lut Desert (trans. by Mahmudi, F.).Geographical Report No.7, Institute of Geography, Tehran University,Tehran.

Dresch, Jean 1971. Studies about the Lut Waste Land (Persian translation byF. Mahmudi). Geographical Report No.' 7, Institute of Geography,Tehran University, Tehran.

Fesharaki, Paridokht 1970. Remote villages of the Lut Margins. GeographicalReport No.4, Ins6tute of Geography, Tehran University, Tehran.

Ganji, M. H. 1974. 32 Geographical Articales, Tehran.Huckride, R. 1971. The Forth Geological Period and the Late Mesolithic Age

in the Kerman Province (Persian translation by Kardavani, P.). Geogra-phical Report No.7, Institute of Geography, Tehran University, Tehran.

Kardavani, Parviz 1970. Some soil samples of the Zangiahmad Lut (Iran).Geographical Report No.3, Institute of Geography, Tehran University,Tehran.

Kardavani, Parviz 1971. Some soil samples of the Shahdad District (in Kerman\;Geographical Report No.6, Institute of Geography, Tehran University,Tehran.

Kardavani, Parviz 1975. From Shahdad to Dehsalm. Studies about the soils,waters, vegetations and the agricultural conditions. Geographical ReportNo. 12, Institute of Geography, Tehran University, Tehran.

98 : PARVIZ KARDAVANI

Mahmudi, F. 1970. The system of running waters of the Lut Desert. Geogra-phical Report No.3, Institute of Geography, Tehran University, Tehran.

Mohajerani, Mustafa 1970. A village in the Lut Margin. Geographical ReportNo.4, Institute of Geography, Tehran University, Tehran.

Monod, Theodore 1971. A brief survey of the physical features of the Lut(Persian translation by Mahmudi, F.). Geographical Report No.7,Institute of Geography, Tehran University, Tehran.

Mostoufi, Ahmad 1972. Shahdad and the Historical Geography of the LutDesert. Geographical Report No.8, Institute of Geography, TehranUniversity, Tehran.