02/12/2008

Desertification in Mauritania - could vetiver be a solution?

NOUAKCHOTT, 2 December 2008 (IRIN) - Environmental degradation, responsible for the dangerous displacement of sand dunes in Mauritania, has wiped out homes, livestock and livelihoods throughout the desert country. An October UN study estimated that land degradation costs nearly US$200 million annually in potential revenue losses and health care expenses.

UN researchers calculated the value of lost cultivable land, disappearing trees and water sources, along with the health care expenses from respiratory and waterborne illnesses related to the poor management of natural resources. The final estimated price tag: 14 percent of the government budget is swallowed up by environmental degradation, or about $192 million. Some scientists have linked desertification, or land degradation in arid and semi-arid regions, to increasing global temperatures, while others emphasise human activities - like farming techniques and tree cutting - that they say have heightened the pace of degradation.

Buried

A botanist based in the capital Nouakchott, Abdellahi Ould Mohammed Vall, told IRIN Mauritania is at the front of the battle against the advancing desert. "The northern Saharan half of the country gets about 100mm of rain a year, while the more humid south gets about 150mm. Because of human behaviour the desert is advancing from north to south more rapidly than estimated decades ago. You see homes buried by sand in the capital." Vall showed IRIN homes in Toujounine, a community 7km outside of Nouakchott. "This home here, even a bulldozer could not save it. This was the bedroom; this fissure is from the pressure of the sand." Five concrete homes with crumbled walls stood empty, surrounded by a row of aluminium-covered shacks.

Desertification

UN researchers estimate that Mauritania's forests - with their charcoal, wood and food products - make up 60 percent of some communities' incomes. The UN report on environmental degradation in Mauritania estimated it has one of the worst rates of deforestation in Africa, costing the country about $84 million every year in lost earnings. Botanist Vall said poverty increases the rates at which people cut down trees, which further impoverishes communities. He added that droughts in the 1970s and 1980s forced nomads to settle, increased competition for water in pastoral areas, and led to increased migration to cities. "People increasingly turned to cutting down trees after droughts to feed their animals and to supplement their pastoral livelihoods. But when forests disappear, there goes a food source for both animals and people," Vall told IRIN. He said desertification has worsened as a result of barren spaces. "There is nothing to stop the harmattan [desert winds]. This is turning into a daily battle. It is very worrying to see bulldozers trying to clear sand from the national roads." Vall said one of the most affected paths is the 150-kilometre stretch from Nouakchott to the city of Boutilimit: "If this road is cut off, 80 percent of the country could not get into the capital to resupply. This would essentially choke off commerce, including food supplies."

Interventions

Vall told IRIN that past tree-planting efforts have not been well planned, for example one using a resistant desert plant called prosopis, which he said the post-colonial government introduced in Mauritania in the 1970s. "This plant flowers year round, is resistant and appeared to be a good candidate to stabilise the desert. But its long roots draw water from local plants. Wherever it is planted, it has had the impact of wiping out plant diversity." Vall said the mistake has been to rely primarily on one species to fight desertification. "We need to diversify solutions. There is no one magic tree, no magic species or solution to hold back the desert. It will take a combination to stabilise the sand and protect communities and livelihoods."

Watch a short video on desertification in Mauritania: http://www.irinnews.org/audiofiles/creeping_deserts_l.html


MY COMMENT:
The huge cost of this environmental crisis makes consideration of the use of Vetiver grass a potentially enconomical tool for the fight against desertification. This could be used to support re-afforrestation, protect infrastructures, especially the roads mentioned in this article. I recently had a report from someone who had made the journey from Morrocco to Senegal by road, and he reported the use of something that looked like vetiver (he is not an expert) being used to stabilise banks on either side of the the new highway. There is a need for artifical watering, especially in the establishment phases, and with such low rainfall. My friend reported the use of very large waterbags attached to drip irrigation pipes.

The use of vetiver could also provide a source of fodder when established, and in contrast to the reports of the use of Prosopis, its long roots actually bring benefits to the plants it neighbours, and promotes plant diversity. It is proven in its Vetiveria zizanioides variety to be non-invasive.

Vetiver has many characteristics makes it suitable to contribute to solutions for Mauritania's and other countries faced with desertification, these are listed in; Vetiver Grass: The Hedge Against Erosion, published by The World Bank in 1987


  • When planted correctly (i.e., close together), Vetiveria zizanioides will quickly form a dense, permanent hedge.
  • It has a strong fibrous root system that penetrates and binds the soil to a depth of up to 3 meters and can withstand the effects of tunneling and cracking.
  • Stiff and erect sterns, which form dense hedges, can stand up to relatively deep water flow (during heavy rain and flash floods)which reduces flow velocity and traps sediment.
  • It is perennial and. requires minimal maintenance.
  • It is practically sterile, and because it produces no stolons or rhizomes it will not become a weed.
  • Its crown is below the surface, which protects the plant against fire and overgrazing.
  • Its sharp leaves and aromatic roots repel rodents, snakes, and similar pests.
  • Its leaves and roots have demonstrated a resistance to most diseases.
  • Once established, it is generally unpalatable to livestock. The young leaves, however, are palatable and can be used for fodder.
  • It is both a xerophyte and a hydrophyte, and once established it can withstand drought, flood, and long periods of water logging.
  • It will not compete with the crop plants it is used to protect. Vetiver grass hedges have been shown to have no negative effect on - and may in fact boost-the yield of neighboring food crops.
  • It is cheap and easy to establish as a hedge and to maintain - as well as to remove if it is no longer wanted.
  • Highly tolerant to a growing medium high in acidity, alkalinity or salinity
  • Highly tolerant to AI, Mn, As, Cd, Cr, Ni, Pb, Hg, Se and Zn in the soils.
  • It will grow in all types of soil textures; this includes sand, shale, and gravel.
    It will grow in a wide range of climates. It is known to grow in areas with average annual rainfall between 200 and 6,000 millimeters and with temperatures ranging from -15 degC to 55 degC.
  • It is a climax plant, and even when all surrounding plants have been destroyed by drought, flood, pests, disease, fire, or other adversity, the vetiver will remain to protect the ground from the onslaught of the next rains.

Vetiver Grass: A Hedge agaist erosion can be obtained from Amazon:
http://www.amazon.co.uk/Vetiver-Grass-Hedge-Against-Erosion/dp/082131405X/ref=sr_1_1?ie=UTF8&s=books&qid=1228257538&sr=8-1

1 commentaire:

Ivo Serentha and Friends a dit…

Greetings from Italy, good luck

hello, Marlow