Thar Desert

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A NASA satellite image of the Thar Desert, with the India-Pakistan border superimposed . The desert is at the center left of the image; the Indus River and its tributaries are to the left side of the desert, and the dark green line at the bottom center of the image is the Aravalli Range.

The Thar Desert (Hindi: (थार रेगिस्तान) , also known as the Great Indian Desert, is a desert located in western India and southeastern Pakistan. It lies mostly in the Indian state of Rajasthan, and extends into the southern portion of Haryana and Punjab states and into northern Gujarat state. In Pakistan, the desert covers eastern Sind province and the southeastern portion of Pakistan's Punjab province. In Pakistan's Punjab province it is known as the Cholistan Desert. Tharparker District of province Sindh Pakistan is also a part of Thar desert. Tharparker Total area is about 20000 sq km. The Thar Desert is bounded on the northwest by the Sutlej River, on the east by the Aravalli Range, on the south by the salt marsh known as the Rann of Kutch (parts of which are sometimes included in the Thar), and on the west by the Indus River. Its boundary to the large thorny steppe to the north is ill-defined. Depending on what areas are included or excluded, the nominal size of the Thar can vary significantly.

According to the WWF definition, the desert proper has 92,200 square miles (238,700 km²). Another source gives the area of the Thar Desert as 446,000 km² extending 805 km (about 500 mi) long and about 485 km (about 300 mi) wide, with 208,110 square kilometres in India. Of the Indian portion, 61% falls in Rajasthan, 20% in Gujarat and 9% in Punjab and Haryana combined. The greater portion lies in Rajasthan, covering about three-fifths of the total geographical area.

[edit] Origin of the Thar Desert

The origin of the Thar Desert is a controversial subject. Some consider it to be 4000 to 10,000 years old, whereas others state that aridity started in this region much earlier. Another theory states that area turned to desert relatively recently: perhaps around 2000 - 1500 BCE. Around this time the Ghaggar ceased to be a major river. It now terminates in the desert. It has been observed through remote sensing techniques that Late Quaternary climatic changes and neotectonics have played a significant role in modifying the drainage courses in this part and a large number of palaeochannels exist.

Most of the studies share the opinion that the palaeochannels of the Sarasvati coincide with the bed of present day Ghaggar and believe that the Sutlej along with the Yamuna once flowed into the present Ghaggar riverbed. It has been postulated that the Sutlej was the main tributary of the Ghaggar and that subsequently the tectonic movements might have forced the Sutlej westwards, the Yamuna eastwards and thus dried up the Ghaggar.

[edit] Physiography and geology

The desert city of Jaipur, Rajasthan

There are three principal landforms in the desert region i.e.

• The predominantly sand covered Thar
• Plains with hills including the central dune free country
• Hills

It is a desolate country where sand is piled up into huge wind blown dunes (technically this is known as an erg). The sand dunes are of three types viz., longitudinal parabolic, transverse and barchans. The first type, running NNE-SSW, i.e. parallel to the prevailing winds, occurs to the south and west of the Thar. The transverse dunes, aligned across the wind direction, to the east and north of Thar and barchans, with the conclave sides facing the wind in the interior, predominant in Central Thar. On the whole the Thar Desert slopes imperceptibly towards the Indus Plain and surface unevenness is mainly due to sand dunes. The dunes in the south are higher, rising sometimes to 152 m whereas in the north they are lower and rise to 16 m above the ground level.

The Aravalli ranges form the main landmark to the south-east of Thar Desert. The more humid conditions that prevail near the Aravallis prevent the extension of Thar Desert towards the east and the Ganges Valley. In the heart of the sand covered area, the bare, dune free country of Barmer, Jaisalmer and Bikaner present an anomaly.

[edit] Desert soils

The soils of the Arid Zone are generally sandy to sandy-loam in texture. The consistency and depth vary according to the topographical features. The low-lying loams are heavier and may have a hard pan of clay, calcium carbonate (CaCO₃) or gypsum. The pH varies between 7 and 9.5. The soils improve in fertility from west and northwest to east and northeast. Desert soils are Regosols of wind blown sand and sandy fluiratile deposits, derived from the disintegration of rock in the subjacent areas and blown in from the coastal region and the Indus Valley. The desert soils occupy the districts of Jodhpur, Bikaner, Churu, Ganganagar, Barmer, Jaisalmer, and Jalore. The Thar consists mainly of the wind-blown sand. The area is covered not only by sheet of sand but also of rocky projections of low elevations which constitute the older rocks of the country. Water is scarce and occurs at great depths, from 30 to 120 m below the ground level.

Some of these soils contain a high percentage of soluble salts in the lower horizons, turning water in the wells poisonous. Being poor in organic matter they show a low loss on ignition. They contain varying amount of calcium carbonate.

[edit] Biodiversity

The Mehrangarh Fort in Jodhpur, India

Stretches of sand in the desert are interspersed by hillocks and sandy and gravel plains. Due to the diversified habitat, the vegetation and animal life in this arid region is very rich. About 23 species of lizard and 25 species of snakes are found here and several of them are endemic to the region.

Some wildlife species, which are fast vanishing in other parts of India, are found in the desert in large numbers such as the Great Indian Bustard (Ardeotis nigriceps), the Blackbuck (Antilope cervicapra), the Indian Gazelle (Gazella bennettii) and the Indian Wild Ass (Equus hemionus khur) in the Rann of Kutch. How these animals and insects survive in these harsh conditions, under such high temperature and without drinking water and green vegetation are amazing. They have evolved excellent survival strategies, their size is smaller than other similar animals living in different conditions, and they are mainly nocturnal. There are certain other factors responsible for the survival of these animals in the desert. Due to the lack of water in this region, transformation of the grasslands into cropland has been very slow. The protection provided to them by a local community, the Bishnois, is also a factor.

The Desert National Park, Jaisalmer, spread over an area of 3162 km², is an excellent example of the ecosystem of the Thar Desert, and its diverse fauna. Great Indian Bustard, Blackbuck, chinkara, desert fox, Bengal fox, wolf, desert cat etc. can be easily seen here. Seashells and massive fossilized tree trunks in this park record the geological history of the desert. The region is a haven for migratory and resident birds of the desert. One can see many eagles, harriers, falcons, buzzards, kestrel and vultures. Short-toed Eagles (Circaetus gallicus), Tawny Eagles (Aquila rapax), Spotted Eagles (Aquila clanga), Laggar Falcons (Falco jugger) and kestrels are the commonest of these.

Tal Chhapar Sanctuary is a very small sanctuary in Churu District, 210 km from Jaipur, in the Shekhawati region. This sanctuary is home to a large population of graceful Blackbuck. Desert Fox and desert cat can also be spotted along with typical avifauna such as partridge and sand grouse.

[edit] Natural vegetation

Desert tribes near Jaisalmer, India

The natural vegetation is classed as Northern Desert Thorn Forest (Champion 1936). These occur in small clumps scattered in a more or less open forms. Density and size of patches increase from West to East following the increase in rainfall. Natural vegetation of Thar Desert is composed of following tree, shrub and herb species.

[edit] Tree species

Acacia leucophloea, Acacia senegal, Anogeissus rotundifolia, Prosopis cineraria, Salvadora oleodes, Tecomella undulata

[edit] Small trees and shrubs

Calligonum polygonoides, Acacia jacquemontii, Balanites roxburghii, Ziziphus nummularia, Calotropis procera, Suaeda fruticosa, Crotolaria burhia, Aerva tomentosa, Clerodendrum multiflrum, Leptadenia pyrotechnica, Lycium barbarum, Grewia populifolia, Commiphora mukul, Euphorbia nerifolia, Cordia rothii, Maytenus emorginata

[edit] Herbs

Eleusine compressa, Dactyloctenium scindicum, Cenchrus biflorus, Cenchrus setigerus, Lasiurus hirsutus, Cynodon dactylon, Panicum turgidum, Panicum antidotale, Dichanthium annulatum, Sporobolus marginatus, Saccharum spontaneum, Cenchrus ciliaris, Desmostachya bipinnata, Cyperus arenarius, Erogrostis species, Ergamopagan species, Phragmitis species, Typha species

[edit] Greening desert and checking shifting sand dunes

Greening desert with plantations of jojoba at Fatehpur, Shekhawati

The soil of the Thar Desert remains dry for a longer period in the year and is therefore most prone to wind erosion. Due to the high velocity of winds in these areas the dust is blown off with it and deposited on fertile lands causing a problem of shifting sand dunes. The movement of the shifting sand buries fences and blocks roads and railway tracks. Permanent solution to this problem of shifting sand dunes can be provided by fixation of the shifting sand dunes with suitable plant species and planting windbreaks and shelterbelts. They also provide protection from hot or cold and desiccating winds and the invasion of sand.

Checking of shifting sand dunes through plantations of Acacia tortilis near Laxmangarh town

The local tree species for planting in the desert region are not many and they are also very slow growing. The introduction of exotic tree species in the desert for plantation has become necessary. Many species of Eucalyptus, Acacia, Cassia and other genera have been tried from Israel, Australia, USA, Russia, Southern Rhodesia, Chile, Peru, Sudan etc. in Thar Desert Acacia tortilis has proved to be the most promising species for desert afforestation and has helped in checking the spread of desert soils to other areas and fixing of sand dunes. The jojoba is one other promising species of economic value found suitable for planting in these areas.

The Rajasthan Canal system is the major irrigation scheme of the Thar Desert and is conceived to reclaim it and also to check spreading of the desert to fertile areas.The river Luni is the only natural water source that drains inside a lake in the desert.

[edit] People

The main occupation of the people in desert is agriculture and animal husbandry. In past years there has been a tremendous increase in human population as well as animal population. This has led to improper control of grazing and extensive cultivation resulting into the deterioration of vegetation resources. The increase of human and livestock population in the desert has lead to deterioration in the ecosystem resulting in degradation of soil fertility. The living standard of the people in the desert is low.

Jodhpur, the largest city in the region, lies in the scrub forest zone. Bikaner and Jaisalmer are located in the desert proper.

A large irrigation and power project has reclaimed areas of the northern and western desert for agriculture. The small population is mostly pastoral, and hide and wool industries are prominent.

The Indian Desert is mainly inhabited by Hindus, Muslims, and Sikhs. The portion in Pakistan is inhabited by primarily by Sindhis and Kolhis. There are around 60% Muslims and 40% Hindus in the Pakistani part of the Thar Desert. A colorful culture rich in tradition prevails in the desert. The people have a great passion for music and poetry.

[edit] See also

• Pokhran

[edit] References

• Govt. of India. Ministry of Food & Agriculture booklet (1965)- soil conservation in the Rajasthan Desert- Work of the Desert Afforestation Research station, Jodhpur.

• Kaul, R.N. (1970). Afforestation in Arid zones (edited): Dr. W. JUNK N.V. Publishers The Hague.

• Gupta, R.K. & Prakash Ishwar (1975). Environmental analysis of the Thar Desert. English Book Depot., Dehra Dun.

• Kaul, R.N. (1967). Trees or grass lands in the Rajasthan- Old problems and New approaches. Indian Forester, 93: 434-435.
• Burdak, L.R. (1982). Recent Advances in Desert Afforestation- Dissertation submitted to Shri R.N. Kaul, Director, Forestry Research, F.R.I., Dehra dun.

• Yashpal, Sahai Baldev, Sood, R.K., and Agarwal, D.P. (1980). "Remote sensing of the 'lost' Saraswati river." Proceedings of the Indian Academy of Sciences (Earth and Planet Science), V. 89, No. 3, pp. 317-331.
• Bakliwal , P.C. and Sharma, S.B. (1980). "On the migration of the river Yamuna". Journal of the Geological Society of India, Vol. 21, Sept. 1980, pp. 461-463.
• Bakliwal, P.C. and Grover, A.K. (1988). "Signature and migration of Sarasvati river in Thar desert, Western India". Record of the Geological Survey of India V 116, Pts. 3-8, pp. 77-86.
• Rajawat, A.S., Sastry, C.V.S. and Narain, A. (1999-a). Application of pyramidal processing on high resolution IRS-1C data for tracing the migration of the Saraswati river in parts of the Thar desert. in "Vedic Sarasvati, Evolutionary History of a Lost River of Northwestern India", Memoir Geological Society of India, Bangalore, No. 42, pp. 259-272.
• Ramasamy, S.M. (1999). Neotectonic controls on the migration of Sarasvati river of the Great Indian desert. in "Vedic Sarasvati, Evolutionary History of a Lost River of Northwestern India", Memoir Geological Society of India, Bangalore, No. 42, pp. 153-162.
• Rajesh Kumar, M., Rajawat, A.S. and Singh, T.N. (2005). Applications of remote sensing for educidate the Palaeochannels in an extended Thar desert, Western Rajasthan, 8th annual International conference, Map India 2005, New Delhi.

[edit] External links

• Thar Desert travel guide from Wikitravel
• Thar Desert (World Wildlife Fund)
• Photos of the Thar desert
• Information about Thar desert In Pakistan
• आपणो राजस्थान

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