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CLOSE THIS BOOKVetiver Grass: A Thin Green Line against Erosion (BOSTID, 1993, 157 p.)
Background and conclusions
VIEW THE DOCUMENTPart 1 Worldwide Experiences
VIEW THE DOCUMENT2 Case Studies
VIEW THE DOCUMENT3 Conclusions

Vetiver Grass: A Thin Green Line against Erosion (BOSTID, 1993, 157 p.)

Background and conclusions

Part 1 Worldwide Experiences

The experiences described in the previous chapter seem to promise a new and perhaps invaluable technique for controlling erosion in the tropics. However, it should not be thought that John Greenfield and Richard Grimshaw were the first to promote vetiver. On the contrary, this plant is one of the better known crops of the tropics. It is only for erosion control that their efforts stand out.

For several centuries vetiver has been commercially cultivated for the scented oil that can be distilled from its roots. This is a treasured ingredient in some of the world's best-known perfumes and soaps and, largely because of its potential as an export commodity, vetiver can be found in at least 70 nations (see table next page). Indeed, during the last century, wherever British, French, and other colonial administrators were assigned, they typically established test plots of essential oil crops-vetiver, citronella, and lemongrass, for instance. In most cases, vetiver still remains in those plots, but only a handful of countries produce the oil commercially (see sidebar, page 78).

Despite this, however, in most places use of the grass to halt soil loss is virtually unknown. Nonetheless, the plant's ability to control erosion is not new. Before World War II, some tropical countries deliberately planted vetiver hedges as contour barriers. This was particularly true in the sugarcane fields of the British Caribbean. However, this technique was essentially forgotten during the disruptions of the war and of the independence that soon followed in many nations. With both the war and the collapse of colonialism, many agricultural advisors left the tropics, taking the knowledge of this technique with them. By the 1960s, only a few people in the former colonies remembered that vetiver could stop erosion.

But vetiver is so persistent that even where it has been abandoned, it has continued to survive for decades or even centuries. For this reason, therefore, the plant can be found throughout the tropics as well as in a few other (sometimes completely unexpected) areas.

Below, we highlight the findings from a correspondence campaign aimed both at locating the grass and at roughly assessing the worldwide experiences with it.

TABLE 1 Countries Where Vetiver is Currently Known To Exist

Africa

Asia

Caribbean

Algeria

Bangladesh

Antigua

Angola

Burma

Barbados

Burundi

China

Cuba

Comoro

India

Dominican Republic

Central African Republic

Indonesia

Haiti

Ethiopia

Japan

Jamaica

Gabon

Malaysia

Martinique

Ghana

Nepal

Puerto Rico

Kenya

Pakistan

St. Lucia

Madagascar

Philippines

St. Vincent

Malawi

Singapore

Trinidad

Mauritius

Sri Lanka

Virgin Islands

Nigeria

Thailand


Rwanda


Pacific

Reunion

Americas


Seychelles

American Samoa


Somalia

Argentina

Cook Islands

South Africa

Brazil

Fiji

Tanzania

Colombia

New Caledonia

Tunisia

Costa Rica

New Guinea

Uganda

French

Tonga

Zaire

Guiana

Western Samoa

Zambia

Guatemala


Zimbabwe

Guyana

Others


Paraguay

France



USA



USSR

ASIA

Vetiver is an Asian plant, probably native to a lowland, swampy area north of New Delhi in India. It has therefore been known to Asians longer than to anyone else.

India

In India, vetiver, or khus as it is more commonly known, has been used since ancient times and is recorded as a medicinal plant in the Ayurvedic era. However, it has been appreciated mainly for its fragrant roots. People weave these roots into mats, baskets, fans, sachets, and ornaments. They also weave them into window coverings that freshen the air of thousands of village homes with a sweet and penetrating scent. Oil from the roots is also used in perfumes. Not only is it pleasantly fragrant, it takes so long to evaporate from the skin that perfumers include it in their soaps and scents to give them "persistence."

The living grass has also long been known as a useful soil binder. However, it was mostly planted around rice paddies, along rivers, and beside canals and ponds to strengthen the banks and keep the land from collapsing into the water.

To line it out across the hill slopes is, for most places, a new and innovative concept. However, since 1987 a number of trials in research stations and farmers' fields have been carried out under the aegis of several of India's state governments, largely with funding from the World Bank. The data is preliminary and is usually not statistically significant, but it is instructive nonetheless.

Some examples follow

Karnataka The state of Karnataka has taken up vetiver for watershed conservation with considerable enthusiasm. Traditionally, the state's farmers have used the grass as boundary plantings, and, although some have placed hedges across the middle of their land-an indication that they understand its value for erosion control-its use to conserve soil and moisture is essentially new.

Among the results of this exploratory research are some from Kabbanala. Even in their first year, the partially formed hedges held back 30 percent more rainfall runoff than graded banks, 47 percent more than conventional contour cultivation, and 24 percent more than hedgerows of leucaena. In addition, they held back 43 percent more soil than graded banks, 74 percent more than contour cultivation, and 54 percent more than leucaena hedges. Moreover, apparently because of the improved soil-moisture levels, the vetiver hedgerows boosted crop yields 6 percent more than those on graded banks, 26 percent more than those on contour cultivation, and 10 percent more than those behind leucaena hedgerows.

Maharashtra and Madhya Pradesh On the black cotton soils in these two states, vetiver has also grown well. It holds back soil and some moisture but (unlike bunds) does not create pools of standing water on these heavy, ill-draining clays. This is important because these soils are so difficult to work with that at present they are only partially used: in the wet season they get too waterlogged; in the dry season they crack open. Bringing the black cotton soils into fuller use could boost India's food production because there are millions of hectares of them.

Tamil Nadu. In Tamil Nadu there has been no formal governmental support thus far, but the Regional Research Station at Aruppukkotai began testing vetiver in 1987. Another grass and two shrubs were later added to the trial. Both grasses grew into hedges far more quickly than the shrubs, and both also proved better at trapping moisture. Vetiver was the best of all. It retained between 3 and 9 percent more moisture than the other plants. Soil behind it contained 26 percent more moisture than that on the control slope, which lacked protective hedges.

All in all, vetiver is starting to be accepted for erosion control. The state's department of agriculture has taken up large-scale multiplication of vetiver. Extension agents are being trained. And contour hedges are being established in selected watersheds. Ultimately, the state plans to protect much of its dryland areas with vetiver.

Andhra Pradesh. The government of Andhra Pradesh has planted vetiver in several watershed-management projects. The results, however, are not completely satisfactory. Because of the state's semiarid climate, the plants take at least three years to grow together into fully functional hedges. Farmers, therefore, are as yet unconvinced of vetiver's value. Indeed, some, concluding that the plant will never do them any good, have plowed it up. Nonetheless, more than three out of four are waiting to see.

Nepal

With its steep slopes and rushing rivers, Nepal is one of the most erosion-prone nations. Vetiver has traditionally been used in the lowland area known as the Terai, but only to stabilize the banks of waterways. Today, it can be found verging many irrigation canals, especially in locations where people tend to walk. The roots are commonly harvested and made into hairbrushes, among other things. Also, basket weavers prefer vetiver stem; they say it holds paint and keeps its color better.

Given the results in neighboring India, much interest in vetiver has recently surfaced in Nepal. Both private organizations and government agencies have established nurseries and are growing the grass. They hope, primarily, to use it to protect the front lip of terraces (of which there are vast numbers), but they see it also as a possible way to stabilize roadsides and to protect (even "renovate") landslide areas. One group is trying to save a small dirt airfield by planting vetiver along the banks of a hungry river that is slowly eating it away.

All efforts so far have been in the Terai and nearby areas. Although it occurs commonly in the vale of Kathmandu, vetiver probably cannot withstand the frigid winters of the uplands, where perhaps the most devastating erosion is occurring.


Sri Lanka

Vetiver traditionally has been used to stabilize some slopes and terraces in tea plantations around Kandy. However, its true potential for Sri Lanka lay unappreciated until 1989 when Keerthi Rajapakse, a retired Assistant Conservator of Forests, helped establish nurseries to supply vetiver planting material to farmers. Rajapakse was elated to find that tobacco cultivators accepted this vegetative contour method with alacrity: soil washing out of hillside tobacco fields is considered to be one of Sri Lanka's major environmental problems.

The plant's ruggedness is almost legendary in Sri Lanka. It is here that people have used crowbars to plant it into bauxite soils. Also, farmers say that couch grass (a creeping weed almost impossible to keep out of crops) cannot penetrate a vetiver hedge.

Indonesia

Although Java is the leading producer of vetiver oil, almost nowhere in Indonesia has the grass been used in erosion control. Ironically, in some places people are convinced that it actually causes erosion. This is because harvesters often rip out the roots (for the oil they contain), leaving behind trenches that foster the severest of soil losses. This has been such a problem that vetiver cultivation has been prohibited in parts of Java. It is, however, a problem of irresponsible harvesting, and is irrelevant to hedges left in place as erosion barriers.

Vetiver is now being established in some of the other islands (in Kalimantan, for example) with some success.

Philippines

Vetiver can be seen throughout the Philippines. It is reported that a few areas have traditionally cultivated it to control erosion-especially around ponds to keep silt from washing in. Nevertheless, the plant is hardly known to Filipinos at large.

Today, however, that is changing. A major project to restabilize the roads destroyed by the 1990 earthquake in Northern Luzon is relying on vetiver. A number of farmers in both Northern Luzon and Central and Eastern Visayas have put in contour vetiver hedges to stop soil losses. The International Rice Research Institute (IRRI) at Los Banos is studying the grass as a way to reduce erosion in upland rice fields and to reinforce the bunds around the paddies in the lowlands. Visayas State College of Agriculture has found that vetiver grows well even on poor and very acid upland soils where little else can survive

China

Although its efforts are just beginning, China is among the nations most active in studying vetiver. Massive projects have been started in a dozen soil-conservation areas. In part this is because of the promise of the early results, but it is also because soil and moisture conservation are among China's national priorities. The country annually loses as much as 400 tons of soil per hectare in certain areas. As a result, the Yellow River is supposedly the most silt laden in the world, and the dry-season levels in the Yangtze are dropping year by year as the ever thinner layer of soil on the hills absorbs less and less moisture. Thus, it is little wonder that there is an almost desperate grasping at what might possibly be a low-cost solution that can be installed on a large scale with local labor and resources.

Vetiver was introduced to China in the 1950s as a source of aromatic oil; when the oil prices dropped, the plant was abandoned. The impetus to test it for erosion control began only in 1988, when it was planted for stabilizing terraces of citrus and tea in Fujian and Jiangxi provinces. Farmers noted that the young citrus and tea plants seemed to grow better (perhaps because of wind protection or increased moisture) and the terraces no longer washed out.

In some areas, vetiver products are already widely popular. In at least one location, prunings from the contour hedges are sold to dairy farmers as a feedstuff and are replacing rice straw as bedding for animals. (The farmers like vetiver straw for bedding not only because it is cheap and rot-resistant, but because it frees up valuable rice straw for sale or for plowing back into the paddy.) Elsewhere, the leaves are employed for mulch.

Although China's Ministry of Water Resources has set up vetiver trials and demonstrations on some severely gullied lands, it is currently more interested in protecting terraces. Nowhere is this interest stronger than in the red-soils area, where engineered terraces have a long record of failing during the intense downpours that occur every few years.

Overall, the results in China have been so promising that during the next few years vetiver will be planted extensively in five provinces. Moreover, Chinese researchers have started their own vetiver-information network, and the government has sponsored a number of vetiver conferences to speed up the exchange of information and results.

Already it has been learned that vetiver can be used south of the Yangtze. However, stands have been established as far north as 36°N in Shangdong Province, where winter temperatures drop to -8°C. So far, there have been few "scientific" trials, but in one carefully documented case vetiver hedges decreased the amount of water running off the slopes by half.

AFRICA

Although the plant is not well known in Africa, it actually can be found growing in scattered locations from Cairo to Cape Town. Also, there is at least one native species that is an African counterpart to this Asian plant. A few African countries have already embarked on exploratory trials with one or both of these species.

Several examples follow.

Kenya

Erosion has long been serious in Kenya, especially in the highlands where the rainfall is heavy and the soils erodible. Vetiver occurs in several locations there, although it is mostly used as an ornamental. It was probably introduced to produce vetiver oil, but it is thought that some was also brought in by a German coffee grower seeking to protect his eroding land. Recently, a government soil specialist found vetiver established on terraces in coffee country in the Machakos District as well as on a dam wall on a farm near Thika. He reports that the plants "are still effectively protecting the soil after at least a decade of neglect."

Vetiver, in principle, could be extremely valuable in the highlands- in plantations of tea, coffee, and pyrethrum, as well as in family gardens and along the sides of roads and tracks. Trials began in 1990 and, despite the short time, the grass is already showing promise

Tanzania

Although now all but unknown in Tanzania, tea planters used vetiver as an erosion-control barrier before World War II. Indeed, an old monograph on tea-growing there makes the following comment: "Grasses are usually detrimental in a high degree to the growth of tea, with apparently one exception, as far as trials and experience goes.

Pantabangan Watershed Catchment, Northern Luzon, the Philippines. This two-year old hedge was planted for the purpose of erosion control. Even in the heavy shade under these trees, the vetiver plants are growing well. The hedges not only reduce soil loss, they also help retain runoff moisture. As a result, the trees grow better and in new tree plantings the number of seedlings that survive can rise dramatically. (R. Grimshaw)

This exception is khus-khus grass [vetiver]. With its close stiff blades it is successfully used . . . in contour hedges. Its tussock habit favors its usefulness as its root system appears to be reasonably restricted in range. It needs to be kept under control by cutting."

Vetiver established on Mount Kilimanjaro, near Arusha, in the final decade of the last century still remains.

Mali

The vetiver highlighted in this report (Vetiveria zizanioides) is probably found throughout West Africa, but far more common at present is an African counterpart, V. nigritana. Whether it, too, will prove useful in erosion control is uncertain, but it has many interesting qualities nonetheless.

For example, V. nigritana occurs across the floodplains of the internal Niger Delta, a vast region (about 20,000 km2) that is inundated for half the year. Here, it occurs mainly on higher ground, and after the flood retreats it becomes lush and green and the herds are then given access to it according to traditional grazing rights. Vetiver (and a mixture of other species) thus provides crucial grazing to the people of the area. Animals take only the young sprouts, but after these are gone, the farmers burn the area to induce a flush of new growth.

For all its importance here, vetiver is not a fine feedstuff. Annual yields vary from 2 to 10 tons of dry matter, depending on the previous flood levels. The International Livestock Centre for Africa (ILCA) found that the whole plant had a digestibility coefficient of 35-40 percent when cut about 2 months after the flood retreated or after being burned-considerably less than the 60-percent level for the other native grass species in the area.

Despite these indifferent figures, however, this African vetiver occurs extensively, and it resists the harsh cycle of floods and fires better than almost any other species there.

Burkina Faso

In neighboring Burkina Faso, Vetiveria nigritana is also important. Indeed, certain tribes rely on the plant throughout their lives. For example, the Bozo (who dwell along the vetiver-covered shores of lakes as well as the Niger River) weave their huts out of vetiver grass or palm fronds.

Nigeria

Vetiver is commonly seen growing wild in Nigeria and probably this is mostly the African species, Vetiveria nigritana. Until recently, it was not used for erosion control but now that is changing. Scientists in Anambra are taking the lead.

A state in the southeast, Anambra is probably the area hardest hit by erosion. It has extensive "badlands," so-called because of steep slopes and gullies that engulf the land and everything on it. Erosion is so severe that in just the last 10 years some 220 towns have lost property worth nearly 6 billion naira($755 million) to 530 greedy gullies. More than 150 people have died from the resulting floods, slips, and cave-ins.

Alarmed, the state government in the early 1980s assembled a team of soil scientists and engineers from its ministries and universities and told them to find out how to halt the further spread of this menace. Initially, many concrete embankments were built, but to little avail. Then some of the scientists came up with the idea of planting strips of grass. Twenty-seven different species were tested; vetiver proved the fastest growing and the most effective. (Initially, V. nigritana was used, although V. zizanioides is now used as well.)

The researchers were excited by these results; however, the local people-even those most afflicted by erosion-remained unconvinced. The plants looked too weak for such a bigjob. The scientists' frustration rose and rose until, in March 199O, Britain's Prince of Wales came to town. With his intense interest in conservation, Prince Charles gladly agreed to plant some vetiver personally. He thereby launched what is officially called "The British Council/Anambra State Project on Erosion Control," but is more commonly known as "Project Vetiver."

Thanks to the heir to the British throne, vetiver planting took off in earnest. "Prince Charles brought prestige to bear on the whole thing," noted Anthony Chigbo, secretary and project engineer of Project Vetiver. "We knew that the long strong roots would go deep and hold the soil in place, but we couldn't convince the average person. They believed that things are good only when they are costly!"

Within a year, field workers were reporting favorable results. Indeed, the Nigerian scientists and their British helpers now jointly predict that vetiver will significantly benefit the environment of Anambra.

Ethiopia

Indian scientists reputedly introduced vetiver to some Ethiopian coffee plantations in the early 1970s. Today the grass is used particularly in Jimma and Kaffa provinces, where small informal nurseries of it are often seen along the roadsides. The Ministry of Coffee and Tea has promoted its use there for at least 10 years.

Ethiopians mainly use vetiver to protect the edges of contour drains, but the plant is becoming increasingly popular as an ornamental around houses. In addition, local farmers have found that the foliage makes excellent mulch, and they say that (compared to napier grass, for example) it is easier to manage because it does not seed or take root when they spread it on their gardens or fields. Pine needles, which were traditionally laid on the floor during coffee ceremonies, are now commonly replaced by vetiver leaves. Vetiver straw is also gaining popularity as a thatch and as a stuffing for mattresses because it resists rot and lasts longer than other straws.

One advantage, widely believed in Ethiopia, is that Bermuda grass and couch grass cannot invade fields through a vetiver hedge. Indeed, the local Amharic name for vetiver means "stops couch grass."

Zimbabwe

Although vetiver is only now getting its first serious trials as an erosion control in Zimbabwe, Mauritian settlers in the Chiredzi area (hot, subtropical lowveld, 600-900 m altitude) have reportedly used it for years to reinforce the banks of irrigation canals. They also took it to the Chipinga area in the Eastern Highlands (warm, subtropical hill country, 900-1,200 m altitude), where a number of coffee planters use it to protect their terraces. Vetiver has also been planted across wet drainage flats (vleis), where it blocks the runoff, thereby keeping the soils moist for months into the dry season.

It has also been reported that tobacco farmers have found that hedges of vetiver around their fields keep out creeping grass weeds, such as kikuyu and couch.

Other African Nations

South Africa Vetiver is cultivated to a limited extent in South Africa and is used as a hedge plant, particularly in Natal where it is used mainly by Mauritian sugarcane growers and is commonly referred to as "Mauritius grass." A company formed for the purpose of putting in vetiver hedges has recently established trials throughout the country (see next chapter).

Madagascar Erosion is such a tremendous problem in Madagascar that farmers have rapidly come to recognize vetiver's usefulness. The grass is being planted, largely under a World Bank initiative. (The Bank's local representative is widely known as "Monsieur Vetivere.") Farmers have found that vetiver fits well with their traditional technique of torching their fields each year. Whereas most other erosion-control plants are destroyed, the vetiver is all but unaffected. Another reputed advantage is that vetiver does not harbor rats. More details are given in the next chapter.

Botswana In Botswana, vetiver (V. nigritana) is known to occur in the Okavango swamp area, but as of 1991 no erosion-control projects have been reported with either V. nigritana or the Indian species (V. zizanioides).

Malawi Vetiver is said to have been used in Malawi for 50 years to stabilize sugarcane

Mauritius Sugarcane growers on Mauritius rely on vetiver and take it for granted. "Any sugarcane grower in Mauritius will tell you that vetiver is used both for erosion control as well as some sort of barrier to prevent noxious weeds such as Bermuda grass from penetrating fields from roads," writes Jean-Claude Autrey, head of the Plant Pathology Division of the Mauritius Sugar Industry Research Institute. "The abundant root system of vetiver is ideal for this purpose."

Zaire The current situation is unreported, but in the 1950s vetiver was commonly found as an ornamental plant and as a border against erosion. Vetiver hedges were sometimes used to fix terraces in place on plantations of cinchona, for example

Central African Republic A solitary note in the Kew Herbarium Collection reports that vetiver is used for stuffing mattresses in the Central African Republic.

Rwanda For more than 30 years vetiver has been used in Rwanda's coffee plantations, apparently for protecting terraces

Gabon According to one report, the grass was planted along ditches and roadsides to conserve the soil and delimit field boundaries

Ghana Vetiver is a common hedge plant in Ghana. It is used particularly along the edges of roads, gardens, and cultivated fields. It is said to prevent a weed called "dub grass" (Desmostachya bipinnata) from invading. The leaves, in their young state, are used as cattle fodder.

Tunisia Apparently, Europeans introduced the grass into Tunisia, and it has been planted alongside pathways to conserve the soil.

CARIBBEAN

The Caribbean is one of the regions where vetiver is best known. Originally, "khus-khus grass" (as it is mostly called) was brought in from India. Today, it is commonly cultivated to avoid soil wash and the invasion of weeds. It is also an ornamental. The dried roots are sometimes used as an insect repellent, to protect clothes from moths, for example.

St. Lucia

Vetiver has been used for erosion control on St. Lucia for at least 40 years (see next chapter). It is still widely valued, particularly on the wetter (southwest) side of the island. The foliage is harvested for mats and handicrafts. In earlier times, thatch was the main vetiver product. These days, however, the only places still employing it are said to be tourist facilities for visiting Americans.

Vetiver is often planted around buildings during construction. For example, the Hess Oil Company recently protected slopes around the schools it built near its refinery by using lines of vetiver.

Trinidad

Seemingly, it was the University of the West Indies that originally recognized vetiver's usefulness for soil conservation. As a result, the plant can now be seen all over Trinidad. Mainly it is planted alongside roads. Indeed, it is vetiver that stabilizes the embankments of many of Trinidad's roads.

At the university research station at St. Michaels, for example, vetiver's potential for stabilizing roadsides under the worst possible conditions can be seen. The road has been bulldozed into the side of the hill, and the resulting debris-subsoil, rock, and shale-is so bad it can hardly be called soil, yet the plants are growing actively and there is no sign of erosion.

Higher up the hills on this research station are found vetiver barriers established in old, eroding, "slash-and-burn" areas on slopes well over 100 percent (45°). Here vetiver must compete with jungle regrowth, heavy grass, and vines, but it has held its own and is doing an excellent job of holding these hillsides together.

These days, Trinidad's forest service is showing renewed interest in vetiver. In Maracas Valley, for example, it has planted fruit trees behind vetiver contour barriers. On extremely steep slopes, as well as on terraces, one can see deep deposits of organic matter trapped behind the grass hedges. Mango trees are obviously benefiting (probably from the extra fertility as well as the deeper percolation of moisture); those away from the barriers are poor by comparison.

Haiti

Because Haiti is the world's second biggest supplier of vetiver oil, the plant is very well known there. Unfortunately, however, in this country of impoverished soils, it has not been widely employed for erosion control. Its extreme robustness can easily be seen because it commonly occurs on the worst possible sites. Even when people are trying to produce vetiver roots commercially, they usually employ the least valuable ground, much of it so worn out that nothing else can survive.

However, only southern Haiti grows vetiver for oil. In the northern part of the country, people leave it in place and use it for soil conservation. "Vetiver works," notes one admiring Haitian. "The minute you remove it the banks fall down."

A good example of vetiver's abilities can be seen on the road from Port-au-Prince to Cap Haitien. Where it cuts through the hills, the embankments on both sides are lined with vetiver. The terrace effects have successfully stabilized these banks, an amazing feat considering their steepness and erodibility

Haitians like several of vetiver's features: it can withstand animals (which eat leucaena, for example), is easy to propagate, is drought hardy, and stays in place with minimum maintenance. Moreover, they point out that people can walk over vetiver without damaging it; doing that to leucaena generates a gap.

One widespread opinion that vetiver impoverishes soils has been debunked. Barrenness does occur in some vetiver areas, but hardly because of the plant. The hillsides had first been damaged to the point where farming was no longer possible, then turned over to goats, and only after the goats could find nothing else to eat did the farmers put in vetiver. For such sites vetiver was merely the last straw.

So far, not much vetiver has been used to stop farm erosion.

Barbados

Vetiver is so common on Barbados that it is part of the landscape, and is much appreciated. A recent tourist brochure, for example, gushes over the plant:

Huge clumps of this bushy grass form continuous borders along most of the country roads in Barbados, providing a soil-erosion barrier around fields of its cousin, the sugarcane. This, however, is perhaps a lesser virtue to most people, the most gracious being the gorgeous smell of this rare fragrance of the tropics. The oil extracted from the roots is used to make a truly Caribbean scent-Khus Khus by Benjamins of Jamaica-available at all fine perfume counters.

The dried roots are also used to make unique souvenirs. These include: clothes hangers covered in khus-khus roots and bound in ribbons. (They give your cupboard a glorious, long-lasting scent, are thick and soft for hanging clothes on, and look very special.)

The leaves of the grass were used extensively to make thatch roofs in early days, but now only as a decorative, "typically tropical" feature. Examples can be seen at Southern Palms Hotel and Ginger Bay. In crafts, khus-khus grass is woven to make Dominican-style rugs at the IDC Handicraft Division. These can be bought by the square for wall-to-wall covering. Ireka, a Rastafarian girl from Mount Hillaby, uses khus-khus grass with balsam to make a whole range of distinct baskets which she sells at her shop at Pelican Village. Roslyn of Barbados uses the grass to make wall hangings and lampshades which are sold at Fine Crafts in the Chattel House Village, and at Articrafts in Norman Centre, Broad Street.

SOUTH AMERICA

Vetiver can probably be found throughout tropical South America, but this is the part of the tropics where it is probably least known. Few South Americans are aware of its presence.

Argentina

The plant is cultivated in the provinces of Chaco and Misiones and it is grown even as far south as Buenos Aires. Its roots are extracted and the essential oil used in perfumes. In Misiones it is employed in thatching ranchos.

Bolivia

Although there has been no research on erosion hedges, the plant is known in Bolivia. Indeed, a project to explore this use has recently been initiated jointly by the Ministry of Agriculture and Campesinos and the Corporation for the Development of Cochabamba. Vetiver plants are now growing well in a nursery in Cochabamba, even though the altitude is 2,600 m. A "vetiver coordination center" is being established by the Organization for Environmental Conservation (AMBA)

Brazil

Brazil produces vetiver oil for its own internal markets and has probably been growing the grass for several centuries. Nothing specific on its use in erosion control has yet been reported, but a scientific paper reviewing vetiver in Brazil reported:

It is a plant of great utility. Its numerous and tangled roots bind the surface where there is danger of breaking the earth apart; its tufts of erect, perennial leaves serve as a fence, protecting crops against wind and dust storms. Later its collected leaves, which have practically no odor, can be used to make hats and its straw canes serve to cover cabanas and barns. Its roots, which have a strong odor, can be transformed into baskets or coarse mats that in certain regions are suspended in doors and windows and frequently wetted with water, perfuming the air and lowering the ambient temperature.

CENTRAL AMERICA

Vetiver can be found scattered throughout Central America, but few people recognize it or are aware of the job it does. Nonetheless, rows of vetiver are often seen where roadsides have been cut into hills.

Costa Rica

Even before the initiatives in India began to arouse worldwide interest, plantings were increasing in an area of small farms and mixed agriculture southwest of San Jose. As a border to prevent erosion, the farmers say vetiver is better than lemongrass, which they had previously used. Vetiver, they assert, tolerates more adversity, is more resistant to stem borers, lasts longer, requires less care, and (because it grows erect) interferes less with field practices.

The grass is commonly used as a hedge plant in the Meseta Central. It is also planted along the top of embankments to prevent rocks and dirt falling onto the road. An Indian group prepares the roots and sells them along with other local products, such as hats and baskets that they fashion out of local plants.

Guatemala

Guatemala once exported vetiver oil to the world. Although the trade stopped years ago, the plant still survives throughout the country. In a few places, it is even used as an erosion barrier. Engineers, for instance, have used it to protect road cuttings from washing out, and coffee planters have long relied on it for soil conservation. This has been mainly on plantations in the western coastal zones, especially in the Department of San Marcos.

Some people (notably Indians in the hills) use Vetiver leaves for thatch, for mulch to "break the rain" on seedbeds, and for bedding for pigs.

Recently, interest in vetiver has been renewed. The government and a private voluntary organization have formed a committee to coordinate vetiver promotion and research. Promising accessions have been located and were planted in six locations in October 1990. Only half of the plantings were watered, but, even though the dry season was just beginning, nearly all the plants survived.

NORTH AMERICA

Vetiver, of course, is a tropical species and would not be expected to grow in the temperate zones. Nonetheless, there are certain parts of North America where it survives and even thrives.

United States

Vetiver has been in Louisiana for at least 150 years. The roots were once routinely relied on to keep moths out of closets during the summers (for which purpose, it is said, the roots remained effective for two years). There was also a small industry producing vetiver oil.

However, this plant, once so well known to Southerners, has been essentially forgotten since at least last century. Nonetheless, field observations suggest that in all that time the neglected plants have not spread, but have remained where planted. Today, vetiver can be found along the banks of many bayous and on old plantations. Even where homesteads were razed or abandoned during the Civil War, vetiver still grows.

The plant is known in other parts of the deep South as well. Although present in Florida for probably a century or more, it has never been collected as an escape from cultivation. There was once a small vetiver-oil industry in Texas, centered mainly in the area near Riviera. The plant was also grown along the Gulf Coast as well as in southern California before World War II.

Recently in Louisiana, exploratory trials using the plant as an erosion barrier have shown remarkable promise (see next chapter).

OCEANIA

As related earlier, it was experiences in Fiji that stimulated the current rebirth of interest in vetiver. However, the grass is known to occur in many parts of the Pacific basin.

Australia

Several native species of Vetiveria grow in Australia (see Appendix B). All are found in the northern half of the continent. Recently, vetiver.

Fiji

The plant was apparently introduced to Fiji in 1907 and tested as a commercial crop before being let loose. Today, it is common in most parts of the islands and is sometimes used to bind rice bunds. Some people drink a tea made by boiling vetiver root in water. In some areas it has spread to populate roadsides and wasteplaces. It is not, however, considered a threat.

Its use in erosion control in the 1950s (as described in the introduction) has been largely forgotten. However, because of newly mandated requirements of the Environmental Protection Authority, a construction company recently used it to restrain erosion and runoff from a building site.


Other Pacific Locations

American Samoa In Aunu'u, the plant has been used around taro fields to choke out weeds.

New Zealand Some samples have been introduced to New Zealand, but so recently that no results have yet been recorded.

New Caledonia In New Caledonia, vetiver has been used extensively to prevent erosion on slopes, particularly along roads. It proved notably effective.

Cook Islands Plants have been on the island of Atiu for at least 30 years, and probably much longer. They show no sign of any natural spreading, and in some former locations they can no longer be found. One particular plant, in a domestic garden, is known to be 28 years old but is still less than 1 m across.

EUROPE

Vetiver, of course, is a tropical plant and should not be expected to occur in Europe. There are, however, several exceptions: one is France.

Vetiver was introduced to the south of France as a potential source of ingredients for the perfume industry of Grasse, on the Cote d'Azur. It still exists there and survives the Mediterranean winter.

Recently, it has been tested as a barrier against soil loss, both there and on the slopes of the Massif Central.

2 Case Studies

In some countries, vetiver was developed or tested as an erosion control completely independent of the World Bank efforts in Asia. These experiences add new insights into the merits and wider applicability of those described in the introduction. Moreover, they are in other parts of the world and in quite different types of sites. Thus, they form a complementary set of case histories that tend both to enhance and qualify those described earlier. Six examples are discussed below

UNITED STATES

In 1989 Fort Polk faced a problem. This army base in Louisiana ("home of the Fighting Fifth Infantry, Motorized") is located at the headwaters of three scenic streams, which were filling with silt as tanks on training maneuvers ripped up the land.

The desecration of these pristine waters not only raised the ire of local communities, it threatened to bring down the heavy hand of civilian authority. Accordingly, army engineers laid check dams across the streams. That, however, did not solve the problem: after the numerous summer thunderstorms, turbid waters sluiced right over the top and muddied the streams as much as before.

Then Mike Materne, the local U.S. Soil Conservation Service agent, was brought in. By coincidence, he had just heard about vetiver. With little hope that it would do much good, he obtained some plants. (Possibly, they were remnants of some grown on Louisiana plantations before the Civil War and were still surviving, despite a century of neglect.)

His pessimism was all the more justified because the sites to be protected seemed hostile to any vegetation: the soil was down to almost bedrock ("C horizon"), the little that remained was very acidic (pH 4.0-4.2), and it contained virtually no fertility. But Materne decided to give vetiver a try-it would be more of a survival test than an erosion-control experiment, he thought.

Accordingly, Materne grew vetiver slips in large pots in a greenhouse, and in the spring of 1990 planted them side by side on the bare and barren slopes immediately above each check dam. He wanted to establish the hedges quickly, and so he dropped a tablet of slow-release fertilizer beside each plant. His hope was that any hedges that formed might filter the turbid waters and thereby stop dirt from ever defiling the dams.

Because of the siting of the dams, some of the vetivers had to be planted into waterlogged soil (owing to a recent downpour, they were standing in water when Materne left the site). Others had to be planted into pure sand, described by Materne as "drier than popcorn." To make matters worse, a gully-washer barrelled through before the plants had a chance to establish deep roots. The speeding water knocked out some and scoured out the soil around others.

Despite all these hazards, however, most of the plants in each of the four sites, from the wettest to the driest, survived. Moreover, a few of them withstood yet another adversity when a freak fire swept through one of the plantings. It scorched and even killed surrounding pine trees, but the vetivers all survived.

In fact they did more than survive-they thrived. In 8 weeks some were almost 2 m tall. In 10 weeks they had grown together into hedges. And on one site, more than 20 cm of sediment had built up behind the thin green line of grass. Some plants held back such a load that after a storm they were temporarily bent over, almost hidden beneath a "sandbar."

By that time the hedges were so effectively filtering the runoff that the old flow of mud and silt down the streams was largely cut off. The check dams were receiving mostly clear water and were functioning as designed: temporarily holding back surplus runoff for later release into the streams.
When first hearing of Materne's proposal to plant vetiver, the local county agent vehemently disapproved, arguing that introducing an exotic plant to the watersheds might create an uncontrollable weed problem. But he was mollified-even overjoyed-when native grasses, wildflowers, shrubs, trees, and vines came crowding in behind the hedges and grew to revegetate the site. He even declared that nothing like it had been seen in the area before.

By that time it was clear that vetiver was acting as much more than an erosion trap; it was a "nurse plant" that was protecting other species and thereby giving these devastated watersheds a chance to heal themselves. Whether because of better soil moisture or the captured silt, the combination of hedges and revegetated slopes solved what had seemed an intractable erosion problem little more than a year before.

ST. LUCIA

Tall, lush, and rising abruptly from the sea, St. Lucia is a prominent island of the Windward chain in the West Indies. Vetiver has been there for perhaps a century and has been reducing soil loss on the volcanic slopes for at least half a century.

Today, vetiver is seen almost everywhere. As one St. Lucian explains, "Around here, people take on to it. The first thing they do when opening a new farm plot is to plant khus [vetiver] along the tracks leading to the plot."

Much of the vetiver seen today results from government interest in the past. From the late 1920s to the 1940s, for example, the government encouraged people to plant the grass. There was no formal policy, but the colonial agent would commonly push for it when he met with large landowners to play a little poker and discuss the latest farming techniques. Farmers on the periphery of the big estates imitated the large landowners, and thus the technique spread. To help the process along, several vetiver-demonstration plots were established at Mon Repos.

Today, the grass is sometimes found planted along the contours of hill slopes, where it functions much as the World Bank describes in India and Fiji. But more often, it is planted along the lower side of the swales (locally known as "drains" or "trained gullies"), which are ditches designed to carry excess water safely off the slopes. There, it reinforces the dirt walls to stop rushing runoff from bursting through. Householders also use it to prevent mud and water from invading their backyards.

Although vetiver is well behaved and much sturdier than other grasses, hedges that are not maintained are said to "deteriorate." As one St. Lucian notes: "The unruly portions must be trimmed and the discipline maintained."

For instance, if the edges aren't cut back, the hedge may become ragged, perhaps because a few plants are unusually rambunctious or because the soil is of uneven quality. Some hedges may break up into clumps. Also, in some old and neglected plants, the centers die out. A timely topping helps keep them "tight."

The plant is easy to trim or top. Surplus vegetation is normally cut off with a shovel or machete. However, vetiver's roots loosen the soil so well that cutting back a hedge on the downslope side can expose highly erodible dirt to the elements.

Nowhere on St. Lucia are the plants considered weeds, and seldom do they spread beyond the hedges. Seedlings are never seen, although newly planted slips sometimes wash out and establish themselves down the slope, where they may look like errant seedlings. By and large the hedges seem to have little effect on neighboring crops, but plants immediately next to an old vetiver hedge sometimes exhibit a reduction in growth.

Another minor problem is that a small shrub-locally called "tibaume" (Croton astroites)-can overcrowd older hedges. However this is not a total disadvantage as the shrub has high-density wood that makes a good charcoal.

One hazard to which the hedges are immune is St. Lucia's fearsome feral goats. These animals are so destructive that people say "all goats' mouths are poisonous." The problem is especially bad at the end of the dry season, when grasses have been grazed out and the goats have started on the trees. The animals, however, graze around vetiver, and the erosion control is unaffected.

In recent decades it is not goats but people who have destroyed many of St. Lucia's vetiver hedges. "Now everyone wants to be very modern and build a wall," says one disgusted observer. "The trouble is, it's more expensive and less effective."

Another resident notes that: "Years ago-when khus was everywhere and the slopes were forested-rivers ran year-round, but now in places they aren't running at all in the dry season because the soil is gone. People are building up on the slopes, and there is more and more water charging down in the rainy season. Everything gets mucky, but everyone wants a house!"

More vetiver, it seems, might be the solution-as it was in the past.

INDIA

In 1956, the National Botanic Gardens (NBG) in Lucknow initiated what seemed a pointless endeavor: a major effort to reclaim a patch of user soils. These soils, which cover nearly 7 million hectares of India, are so alkaline and salty that they have long been classified as unfit for agriculture.

However, the director of the NBG, K.N. Kaul, decided to tackle the impossible. He began his project around the village of Banthra (just outside Lucknow, on the Kanpur road), where many hectares of user soil had been lying unused for years.

To those who saw the area, the prospect of producing anything useful appeared bleak. The soil was bare, hard, and highly eroded. Hard pans had surfaced in places, and a thick crust of sodium clay stretched as far as the eye could see. The alkalinity was extreme (as high as pH 11) and just 1 m below the surface was an impermeable layer of calcium carbonate that blocked plant roots and produced widespread waterlogging in the monsoon season. The only vegetation to be seen was sparse clumps of grasses and isolated specimens of the weed Calotropis procera with its salt-filled bladders and toxic leaves.

Administrators from the state government felt that this experiment, like all the previous ones on user soils, was bound to fail. They gladly made the site available without charge. After all, what had they to lose? The people of Banthra were living in utter poverty, and many had resorted to crime to survive. Even the Banthra people themselves were less than enthusiastic, convinced that cultivating such hard and barren land would demand tractors, bulldozers, subsoilers, rollers, and other heavy machinery. They could foresee only big costs and small rewards.

However, they soon found that things were to be different. Professor Kaul planned to employ not machinery, but organic amendments and natural methods. His goal was to create a self-sustaining agriculture based on alkali-tolerant herbs, shrubs, and trees. It seemed a good idea, but at first nothing would grow at Banthra. Even the most resilient food crops died of stress and exposure. This project certainly seemed to be the failure everyone had predicted.

But then everything changed, and it was vetiver that made the difference. This rugged grass possessed an exceptional ability to withstand the heat, the drought, the salt, the alkalinity, and the waterlogging. Without even amendments or fertilizers, it could establish itself when planted directly into the user concretion.

And vetiver did much more. As was later discovered in Louisiana, it proved to be a "first aid" plant that started the process of healing the site. Vetiver stretching in rows across the land gave other plants a chance to survive, too. It blocked the drying winds and reduced the erosion they caused. Indeed, the better microclimate and environment between the rows helped the NBG researchers establish a workable farming system. In the process, the soil began slowly to improve. This was especially so after the researchers dug drainage systems and created ponds for collecting runoff and recharging groundwaters.

The land at Banthra is almost flat, and Professor Kaul initially thought of vetiver not as an erosion-control barrier but as a potential commercial crop. The villagers could sell the roots for essential oil, he thought. Nonetheless, the outcome exemplifies the plant's ability to survive adversity and to foster the growth of relatively less tolerant species.

That is certainly what happened at Banthra. Today it is a lovely parkland: green, shady, and beautiful. Legumes of various types now flourish, and 18 species of plants (belonging to 15 families) that had not been recorded there at the time Professor Kaul began his work are now common. The land has been transformed. It now supports a healthy mix of woodland, grassland, and cropland. As the leader of the project at the time stated with relief, "The final proof came with the accumulation of humus and eventually with the appearance of earthworms. Although this took 12-15 years, it was a good reward for the efforts we had started in the mid-'50s with 'first-aid' species like vetiver. This was indeed a day of rejoicing for us all."

MALAYSIA

In Malaysia, where the rain can fall in sheets and the slopes are steep and loose, soil losses can be among the severest in the world. Vetiver hedges would seem to be a godsend, but (at least in recent times) they were unappreciated until P.K. Yoon read about the World Bank's results in India and immediately set out to see for himself if vetiver worked.

Yoon is a scientist with the Rubber Research Institute of Malaysia, and he embarked on this venture in 1989 with less than great enthusiasm: "When I first saw a clump of rather undistinguished-looking grass, it looked so ordinary and so frighteningly similar to the horrible 'lalang' [Imperata cylindrica, a feared tropical weed] that I was thoroughly put off. However, also having seen massive erosion problems, especially on steep hills, I was prepared to have a look-see at anything that might work."

Luckily, Yoon managed to locate a vetiver clump near the city of Taiping. He carefully broke up the clump into 57 separate plants (tillers) and planted them out in individual polybags.
Vetiver proved easy to multiply. Much watering and a little slow-release fertilizer greatly boosted the growth and the production of tillers, and topping the clumps back to 40 cm encouraged tillering even more.

At first, Yoon threw away the tops that had been cut off; however, he eventually noticed that as long as the plants were at least 3 months old, the discards included many culms. These jointed stems had buds at each joint, and Yoon found that laying the stems on damp sand and keeping them under mist caused the buds to sprout and produce new plantlets. Slitting the leaf sheath increased the success rate to the point that, after just 8 weeks, three out of every four nodes took root and began to grow. With as many as 17 nodes to a culm, this has proven a quick and efficient way to propagate vetiver without ever digging any up.

By these methods Yoon was able to convert the 57 starting plants into an amazing 16,000 tillers in just the first 7 months. Within 18 months he had distributed 200,000 plants for testing at various sites throughout Malaysia.

To see if vetiver had any chance of stopping soil loss, Yoon set up a simple demonstration at his research station at Sungei Buloh. The terrain was gently undulating (4-5° slope), and erosion had already formed a small gully. He planted slips of vetiver across the gully in five widely separated rows. After only 3 months, they had grown into hedgerows and had trapped so much topsoil that the gully had gone; in fact, what was previously a gentle slope had become level platforms, each faced by a bristly line of grass (see top of next page).

As a demonstration, it was very successful. "Every visitor we've had to date has been impressed enough to want to use vetiver on their own land," notes Yoon.

Next he set up a larger demonstration. A hillside was divided into four portions; two were planted with vetiver, the other two with cow grass (Paspalum conjugatum) and New Guinea grass (Panicum maximum) as is normally practiced in Malaysia. At the side and bottom, corrugated-metal walls were built to deflect runoff into drums, where it could be measured and its silt content analyzed. All this was rendered useless, however, when such heavy rains fell for 2 days in October 1990 that the runoff collapsed the metal walls and washed away the drums. The vetiver-planted portions remained pretty much intact; the rows of vetiver did their job, but with no control slope for comparison the precise figures Yoon had hoped for could not be obtained.

Yoon's other work concentrated on testing vetiver's ability to protect highway embankments, steep banks in housing estates, and hillsides in large new plantations. In such sites, saving a few dollars in propagation and planting costs is trivial, and Yoon grows out the plants in polybags to ensure that they rapidly produce uniform hedges when placed out on the site.

Concerned that the grass might host diseases that could affect Malaysia's crops, Yoon has surveyed the various plantings for pests. However, despite the large number of sites, there were only two serious fungal attacks-both of them in crowded nurseries. Moreover, the problem was easily solved: topping the plants removed the diseased parts, and the subsequent growth was normal.

An orchardist who had received some of Yoon's plants discovered an interesting application. To provide the abundant water essential to his new orchard, he excavated a series of ponds and planted the grass on the embankments. The plants grew extremely well, and they stabilized even the filled-earth sections so quickly that within 5 months the embankments were able to hold back waters 3 m deep. During the rainy weather many of the plants survived more than a month under water.

The key innovation, however, occurred when the orchardist added fish to the ponds. "He found that Chinese grass carp love to eat vetiver leaves," notes Yoon, "and he now cuts off the top of the grass and routinely feeds it to the fish. He is so pleased with this that he is digging more ponds. Also, neighboring smallholders are introducing vetiver and fish-rearing to their farms."

Young tops were readily consumed by sheep as well. Moreover, repeated cutting not only feeds the animals, it keeps the hedgerows dense and neat and in the finest condition for controlling erosion.

Yoon has also tried vetiver tops as a mulch. Farmers and gardeners in Malaysia commonly use lalang for this purpose. Preliminary observations showed that vetiver lasted much longer and did not cause any weed problem. Analysis showed that the vetiver mulch had considerable amounts of available nutrients (including nitrogen, phosphorus, potassium, and magnesium). Yoon concluded, therefore, that vetiver will be used for much more than just erosion control; it will also be a ready supply of quality mulch for suppressing weeds, conserving soil moisture, and boosting crop yields.

All these hands-on experiences have converted the former skeptic into a vetiver enthusiast: "Our work was done over a period of less than 2 years, but the results clearly show vetiver's vast potentials. They are just too tempting for anyone not to look further into it!"

SOUTH AFRICA

Vetiver has been part of Tony Tantum's life since 1966, when he first discovered Mauritian sugarcane farmers using it to stabilize drains in Malawi. To him, the hedges on that sugar estate in the Lower Shire Valley seemed very effective. At the time he learned that vetiver also had other uses: the culms were used as brooms, and small bundles of the roots, tied with a ribbon, were used for scenting cupboards.

In the 1980s, he moved to South Africa and found that the South African sugar industry had been using vetiver for a long time-perhaps for more than 100 years. "Hedges of the grass were put in to keep equipment from falling off the slopes," explains Tantum. "However, this was not practiced by everyone; it was pretty much limited to the French Mauritians growing sugar in Natal. They don't get along with the other sugar growers, so the technique did not spread."

Today, however, this method of erosion control is escalating. Indeed, Tantum has built a broad national base of institutional awareness of vetiver. His main resources have been Cedara College, Elsonberg College, the Institute of Commercial Forestry Research, the Environmental Authority, Natural Resources, and administrators in Transkei, QwaQwa, Bophuthatswana, and KwaNdebele. He has, moreover, generated a similar network of institutional interest in Lesotho, Zimbabwe, and Mozambique.

Tantum reports that he meets with skepticism and resistance from mechanical engineers (which is not surprising since engineered systems have dominated South Africa's erosion control for 30 years) but that most people are persuaded pretty quickly.

One convert is a North Coast farmer who was on his ninth ratoon (annual cutting) of sugarcane and preparing to replant the field when Tantum persuaded him to put in vetiver hedges. The grass would act as an "erosion safety net" when the cane was plowed out the following year, he said. But the unexpected occurred: the ninth ratoon turned out to be the farmer's highest yielding field. Perhaps the dense grass hedges were improving soil moisture to the point where an unprecedented tenth ratoon would be profitable; perhaps not. But the farmer faced a dilemma: keep the cane or replace it?

As a result of such experiences, the South African Sugar Experimental Farm is conducting a 5-hectare study of soil loss and water retention in sugarcane using vetiver.

Tantum's company, which puts in vetiver hedges under contract, has helped establish vetiver trials all over the Republic. Several are on horrendous sites. In the Western Cape, for example, the grass has been established on pure sand and on badly eroded kaolin clay. Elsewhere in the Cape, on dumps of slime residue from cement manufacture, it is doing well despite the worst drought in many years.

The trial on the pure sand was particularly impressive. It was on the coast near Camps Bay, on the road to Llandudno. Eroding road banks have long been a problem in the area. When Tantum's crew arrived, the debris of many previous attempts-poles, wire, and plastic netting, for example-was evident. It was clear that this would be an extreme test for vetiver. The soil was barren orange grit and the steep slope faced the sea, exposed to salt spray and sea winds. The grass was planted in April 1990, and more than 90 percent of the plants survived. Within about 2 months, they started to stabilize the site.

Tantum has also established trials for several government agencies. The Department of Railways, for instance, approached him when a steep (1:1) embankment near Shongweni collapsed after a downpour of 100 mm. The embankment had supposedly been stabilized with a covering of kikuyu grass. The railways department asked Tantum if vetiver could do better. Tantum planted rows of vetiver straight into the collapsed, eroded, and unprepared surface. The soil was very poor, but no fertilizer was used. Within one month the rifling had stopped. Within 2 months residual kikuyu grass had begun to cover and stabilize the soil between the vetiver lines. However, neighboring areas (lacking vetiver) remained bare. For them, soil had to be imported and the area resodded with kikuyu grass.

In 1990, Niels Carstens of the Roads Department (Cape Provincial Administration) asked Tantum if vetiver could solve the serious erosion at the Stellenbosch flyover (Exit 22 of Highway N2 to Cape Town). The embankment here was very steep; the so-called "soil," pure white sand. Vetiver was planted in April 1990, closely spaced and without fertilizer. Virtually all the plants survived, and natural terrace formation was already visible before the end of the year.

In another trial in the Stellenbosch area (on the R44 road to Paarl), a steep road bank with very poor white clay subsoil was planted. Nothing grew there until April 1990, when vetiver was put in. Within 7 months the grass was tillering well, and the bottom hedge had built up between 70 and 100 mm of soil.

An interesting project, developed by the Institute of Commercial Forestry Research, has used vetiver hedges to stop soil loss in firebreaks, which were a major source of erosion. Thanks to the institute's work, the South African forestry industry has now accepted vetiver for this use. Also, the insurers of the industry have accepted that vetiver hedges on firebreaks are not a fire hazard. In June of each year, the hedges are treated with a contact herbicide and burned a week later. Within 2 weeks they become green belts across the firebreaks, blocking the former erosion.

Chris Nicolson, of the Institute of Commercial Forestry Research, is now developing an evergreen ground cover to fill the space between the hedges. This is a major development for the industry and perhaps not only in South Africa because firebreaks are a source of erosion in forests worldwide.

MADAGASCAR

It is no news to anyone that Madagascar has a problem with soil erosion as bad as can be found anywhere in the world. On the cultivated uplands (slopes up to 100 percent or more), minor surface rifling rapidly evolves into fierce gullying gouges out vast areas and turns the rivers to soup. Often, this gullying starts along the elaborate networks of drainage ditches the farmers dig around their fields. These ditches are intended to carry away the runoff, but they often wash out. Even when intact, they take away valuable moisture so that the mountain soils tend to quickly dry out when the rains cease.

Currently, however, the only other efforts to halt this disaster on Madagascar consist mainly of scattered reforestation projects. Their impact is often minimal because, in the absence of adequate ground cover, few of the seedlings survive and those that do grow slowly. Moreover, many end up destroyed by bushfires that recur each year.

All this was known to Thomas Bredero, the World Bank's senior agriculturist in Antananarivo. Thus, in 1988, after seeing how well vetiver performed in World Bank projects in India, he began searching Madagascar for the grass. Fortunately, French colonists had previously introduced it to produce vetiver oil. Bredero found remains of their plantations, although they were scattered and few. His main problem was how to finance and establish nurseries and demonstrations throughout the country. His first effort failed because the grower demanded gold for every vetiver plant he produced. A second was more successful, despite a seemingly never-ending drought that beganjust after planting. This time, a commercial farmer produced about 10 hectares of nursery, and about 90 primary schools in the Lac Alaotra area planted nurseries of 1 hectare each. As a result, farmer groups were soon being provided with vetiver slips. By late 1991, on-farm demonstrations could be found in 11 of Madagascar's 22 extension districts. It was at this point that
Bredero came to be known as "Monsieur Vetivere."

However, it was clear from the outset that getting farmers to accept vetiver was not going to be easy. "There were the usual arguments- that it has no 'economic' purposes (such as improving soil fertility and cattle fodder)," said Bredero, "and that other 'economically more useful' species are available."

But much of the opposition subsided when Bredero planted a vetiver hedge in the presidential garden. It solved an incipient erosion problem on the palace grounds and greatly pleased the president.

Madagascar's extension service now recommends vetiver for on-farm soil and water conservation in combination with other measures such as contour cultivation, dead furrows' continuous vegetative cover, and crop rotations. On slopes under 5 percent, where burning is not practiced, a grass called "kisosi" (a species of Panicum, see Appendix B) is also recommended.

In these combinations, vetiver is employed as a first line of protection, not only against erosion but also against ground fires. It complements agriculture, horticulture, and reforestation. With well-established vetiver lines, for example, many other kinds of land uses that lead to soil conservation are being developed: annual crops, perennial crops (notably fruits and fodders), and reforestation, for example.

Although at first skeptical, the forestry research department. It changed its position when tests on its own sites showed that vetiver by itself slows runoff as well as a dense forest cover could.
In a number of Madagascar's rural areas, farmers have discovered for themselves vetiver's effectiveness for stabilizing dams, rice-field bunds, and irrigation works, as well as for protecting roads that can flood and wash out.

Bredero's next major challenge is to prove vetiver's usefulness in preventing the devastating gullies and ravines (known as lavaka in the Malgache language) from chewing up more land. They are so big and there are so many of them that the sandstone formations north of the capital and around Lac Alaotra constitute an alarming sight.

Bredero is now tackling the problem from two sides. First, vetiver is planted on contour lines around the upper edges as well as down the sides of the ravines to slow down and disperse runoff coming from the top of the mountains. Second, wooden poles are driven into the sand at the bottom of the ravines. The soil retained by these wooden palisades is planted with vetiver, bamboo, and fast-growing and fire resistant trees and shrubs. The result is a dense vegetative cover. About 10 of these pilot-sized watershed-protection projects are now established, and early experiences seem encouraging.

The final verdict on vetiver is not yet in, but this grass just might be the answer to Madagascar's raging erosion-one of the worst local environmental problems on the planet.

3 Conclusions

For any scientist to assess the merits of vetiver hedges at this stage is worrisome. Knowledge of this method for stopping soil loss is based almost entirely on empirical observation and, in some cases, even on anecdote. Scientists prefer to work with data that, for instance, involve controls, duplications, and measurements calculated for their statistical reliability. With vetiver, few such figures or factual comparisons are available.

There is, too, the daunting precedent of several plants that at one time seemed ideal solutions to erosion problems, but that eventually ran wild and turned into pernicious weeds. The early enthusiasm for those species rings hollow, now that its results can be seen.

Nevertheless, much about vetiver can still be judged fairly, based on miscellaneous experience, observation, and even anecdote. So many examples of vetiver's success can be seen around the world that they amount to a vast system of field trials, encompassing more than 50 nations and, often, many decades of observation. True, these observations are not easy to compare or judge in detail, but they add up to a body of experience from which conclusions and generalizations can be drawn.

Further, it is important also to place this in context. In global terms, erosion is continually increasing. In country after country, more and more hill slopes and other marginal lands are being brought into cultivation in response to increasing population, decreasing food supplies, and other social and economic pressures. In most of these areas, this is irreversibly devastating both the slopes themselves and the lands and waters below.

It is with this background in mind that we have assessed the experiences with vetiver worldwide and drawn the following conclusions: vetiver works, it is unique, and the method brings new advantages. Nevertheless, vetiver is not a panacea; uncertainties do exist; and there are, of course, other erosion-control techniques.

Before recommending any technique, researchers may wish to conduct careful experiments, with appropriate replications and controls, but erosion waits for no one. Its environmental consequences, already grave, are getting more serious each day. Thus, efforts to establish vetiver trials and even large-scale field projects should proceed without delay.

VETIVER WORKS

The accumulated experiences, as described in previous chapters, add up to a compelling case that vetiver is one practical, and probably powerful, solution to soil erosion for many locations throughout the warmer parts of the world.

To the casual observer, it may seem implausible that a hedge of grass only one plant wide could block the movement of soil under torrential tropical rainfall. However, vetiver is not like a lawn or pasture species; it is a big, coarse, very tough bunch grass and it grows to about I m wide at the base with a clustered mass of dense stems. Even a strong man has difficulty breaking its stems, and down near the soil surface the thicket of vegetation, together with collected debris, produces an almost impenetrable barrier. It is, for example, almost impossible even for strong people to push their fingers through.

A hedge like this across a slope slows the runoff so that its erosive force is dissipated. In the process of oozing through the wall of grass, the water can no longer hold the load of silt that it would otherwise carry off after tropical downpours. Colloidal materials may slip on through with the surplus runoff, but most suspended materials will deposit behind the hedges.

Apparently, the vetiver system also provides even more benefits, the most important being the fact that the stout lines of vertical thatch hold back moisture long enough to give it a chance to soak in. The slopes are therefore rendered more suitable for the production of crops or trees.

Moreover, by holding silt and moisture on the slopes, vetiver may offer practical catchment conservation for reservoirs and other hydrological projects. In many places this will undoubtedly prove impractical, but it could nonetheless be invaluable to certain projects involving canals, rivers, reservoirs, flood-control facilities, and other waterways to even out the flow of runoff throughout the year. Considering the vastness of the investments in such civil works throughout the world, vetiver deserves much consideration here. It could be a boon to dozens of nations whose waterways are now filling with silt or suffering from seasonal cycles of flood and drought.

VETIVER IS UNIQUE

Although other grasses and trees have been used as vegetative barriers for soil conservation, vetiver seems to combine several characteristics that make it special:

· It reduces erosion when in a hedge just one plant wide. (Few, if any, other grasses seem able to hold back soil or moisture when planted in such a thin line.)
· Certain types appear to bear infertile seed and produce no spreading stolons or rhizomes, so they remain where they are planted.
· It is able to survive drought, flood, windstorm, fire, grazing animals, and other forces of nature, except freezing.
· It has a deep-penetrating root system.
· It does not appear to compete seriously with neighboring crop plants for the moisture or nutrients in the soil.
· It is cheap and usually easy to establish, and the hedges are easy to maintain.
· It is not difficult to remove if no longer wanted.
· It is (at least so far) largely free of insects and diseases and does not appear to be a host for any serious pests or pathogens that attack crops.
· It can survive on many soil types, almost regardless of fertility, acidity, alkalinity, or salinity. (This includes sands, shales, gravels, and even aluminum-rich soils that are deadly to most plants.)
· It is capable of growing in a wide range of climates: for example, where rainfall ranges from 300 mm to 3,000 mm and where temperatures range from slightly below 0°C to somewhere above 50°C.

VETIVER BRINGS NEW ADVANTAGES

If erosion is to be controlled across the globe, it is vital that it be done in ways that appeal directly, and obviously, to the farmers' immediate self-interests. Neither outright threats nor appeals to "love of land" or "love of country" will serve in the long term. Ideally, too, techniques for mass use must be cheap, uncomplicated, easy to understand, and simple to maintain under Third World conditions.

Vetiver can be all of these things.

Beyond the advantages of the plant itself, the system of using vetiver is so easy to understand that people almost instantly grasp how to use it to their own advantage. Moreover, putting in vetiver hedges has several other benefits:

· It does not require that each site be individually designed.
· It does not require foreign exchange or expensive equipment.
· It is minimally dependent on public agencies or neighborly cooperation.
· It does not need laborious maintenance.
· It does not require careful layouts or high-quality control.

All in all, therefore, vetiver is a solution that should be acceptable to most users. It seems promising as a way for local people to involve themselves naturally in erosion-control activities-something that national planners have long dreamed of.

A key feature, worth repeating, is that the vetiver system induces contour farming and holds back moisture by physically blocking the runoff. Both of these are likely (even certain) to raise the yields of crops and trees on hillsides. Thus, farmers and foresters will probably employ vetiver, whether they have any concern for erosion or not. Self-interest should drive them.

VETIVER IS NOT A PANACEA

Vetiver is not a panacea; it cannot solve all the problems. Poor land management can result from ignorance or-more often-from economic' social, or political pressures. For example, rents may be too high, fertilizers unavailable, or crop prices too low-all of which can force farmers to overexploit their land in their attempts to grow more.

Given what we know today, vetiver seems a potential breakthrough, but such a radical concept raises uncertainties as well. Some difficulties however, can already be foreseen.

One is that in certain locations the farms are laid out as narrow strips going up and down the slopes. In practical terms, such farms can be plowed only vertically. Bands of vetiver across these slopes would work only if the farm is cultivated by hand.

Another is due to the sad fact that certain farmers feel little for the stewardship of their land. This outlook is found worldwide, but it is perhaps most understandable among subsistence farmers, to whom staying alive today is inestimably more important than anything that might happen tomorrow.
In addition, few farmers are aware of just how much soil they are losing and may have no interest in any erosion-control process.

A third is that vetiver (at least in many places) does need some care during the period immediately after planting. Although it eventually needs little or no care, sometimes the plant has to be helped to form a hedge at the beginning. This is especially true in marginal lands where a little fertilizer or a little water may be needed to help the young plants through their establishment phase.

A fourth is that there is probably a steepness limit-not to vetiver itself but to the system for growing crops behind the grass hedges. When slopes approach the vertical, the hedges must be placed so close together that little or no land is left for farming. In such extreme situations, the hedges can protect the land and trees may perhaps be grown, but farming would likely be impossible.

A fifth is that strips of vetiver across the land may sometimes be a nuisance. (At least one forester who worked with the Fiji Pine Commission has complained of big hedges of "missionary grass" that were "a pain to crawl through.") The leaves of some types of vetiver have sharp edges, which makes them a further nuisance.

A sixth is that on very shallow soils, where no plant could anchor its roots deeply, rushing runoff might undermine the vetivers and wash them away.

Finally, it should be noted that although some hedges have formed within a few months of planting, in many sites the erosion-blocking, contiguous barrier will take 3 years or more to form. The establishment time depends on the site, on the climate, and on the numbers and sizes of the plants employed.

Vetiver may fail to form functional hedges on sites with only moderate temperatures and sunlight. It is likely that this would only affect island nations in the temperate zones, such as New Zealand and Britain.

Why Conservation Schemes Fail

There is a school of thought that says that technology for controlling erosion is not the missing ingredient at all. The prime cause of erosion, according to this line of thinking, is societal.

"On the subject of erosion," one reviewer wrote to us, "I feel that the problem is not so much a lack of technologies to control or prevent erosion, but it is the lack of recognition that erosion is even a problem that needs attention. Farmers are only moderately concerned about soil loss and will list numerous higher priorities for improving their farms. Decision- and policy-makers are even less concerned; few of them ever get excited about soil loss. Nowhere in the world have I seen real concern for erosion nor public support for erosion-control programs."

Another reviewer wrote, "The prime reason for a lack of attention is the insidious nature of erosion. One rainstorm can remove a millimeter of soil from one hectare. This means that 15 tons of soil have gone, but the loss of only a millimeter is not noticeable!"

Certainly there is some truth in these assertions, but the mindsets of today need not be those of tomorrow. Changes can be made. Piers Blaikie, for instance, claims that governments can create the right policy environment for attacking the causes of soil erosion by stimulating such actions as:

· Research (notably on specific techniques);
· Legislation (for example, banning very damaging practices);
· Supporting extension and facilitating credit (and tying both to the positive encouragement of soil-conserving crops);
· Rural development (for instance, strengthening local institutions);
· Improving administrative structures (so that bureaucratic decisions are based less on fiat and more on experience);
· Land tenure reform (so that farmers have a vested interest in erosion control);
· Adjusting prices for farm products and inputs (especially eliminating those that subsidize unsound practices); and
· Education, training, monitoring, and evaluation (of both farmers and administrators).

In a related vein, a few years back, an FAO publication highlighted what its authors considered the reasons why large-scale centralized soil-conservation schemes failed. It identified the following reasons:

· Erosion prevention is seen as an end in itself.
· There are very high labor requirements.
· The effects on agricultural production are usually ignored.
· Farmers, seeing few short-term benefits, lack motivation.
· Farmers and herders are regarded as part of the problem to be solved.
· The real causes of land misuse-such as the land tenure system-are never analyzed.

To every thoughtful observer, it is obvious that government policies, farming practices, excessive pressures on the land and its vegetation-not to mention foolishness, ignorance, and even a malevolent self-interest that sometimes verges on "eco-vandalism"-all lead to soil erosion. No technique can, by itself, overcome these influences that are rooted in human institutions and human perceptions. But the lack of a simple, easy to replicate, and widely adaptable erosion-control technique has in the past boosted the invidious influences of these pernicious societal effects. Vetiver, therefore, might help. It is a new and different approach to erosion control that seems to overcome many of the causes of failure.

Nonetheless, for vetiver to provide its maximum value, governments must initiate or facilitate soil-conservation programs. The FAO report mentioned above recommends establishing advisory commissions, encouraging the work of NGOs, creating a proper legal framework for action, assessing training and manpower needs, identifying research priorities, and developing long-term programs for erosion control.

VETIVER IS COMPATIBLE

Vetiver isn't the only erosion-control technique, of course. Others include the following:

· Engineered systems, such as terraces, rock walls, and earthen berms and bunds;
· Plants that spread over the land;
· Broad (as opposed to narrow) strips of grass;
· Tied ridges;
· Contour cultivation, mulches, crop rotations, strip-cropping, and no-till farming; and
· Forestry, agroforestry, and living fences.

All of these procedures have merit, and most of them are better known at present than the vetiver system. Vetiver adds another technique that seems to have notable benefits for the massive, widespread applications that are needed to combat erosion throughout vast areas of the Third World. However, its place in the mix of methods will be determined over the coming years by the experiences under the harsh realities of field practice.

Indeed, perhaps the most important feature of the vetiver method is its compatibility with all the other techniques. Vetiver is already being planted in several countries to reinforce and improve the stability of terraces, berms, and bunds. It has outstanding promise as a "safety line" to anchor broad strips of other grasses, such as napier grass. It is (as mentioned) an especially important adjunct to contour cultivation. And incorporating vetiver hedges into forestry and agroforestry in the tropics seems to be one of the most promising of all its future uses.

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