THE VETIVER SYSTEM

FOR

AGRICULTURE AND RELATED USES

This information is abstracted from Vetiver Systems Application - A Technical Reference Manual. Authors - Paul Truong, Tran Tan Van, and Elise Pinners. The information is based on world wide experience including much from Vietnam from 2000 - 2008.

CONTENTS

1. INTRODUCTION

2. SOIL AND WATER CONSERVATION

2.1 Soil and water conservation principles

2.2 Characteristics of vetiver suitable for soil and water practices

2.3 Contour banks or terrace systems versus the Vetiver System

2.4 Applications on flood plains

2.5 Applications on sloping land

2.6 Effects of soil loss

2.7 Design and extension: farmers’ considerations

3. OTHER MAJOR ON-FARM APPLICATIONS

3.1 Crop protection: stem borer control in maize and rice (and sugar cane)

3.2 Animal feed

3.3 Mulch to control weed and conserve moisture

3.4 Vetiver Seedlings for the market

4. FARMLAND REHABILITATION & PROTECTION OF FLOODREFUGE COMMUNITIES

4.1 Sand dune stabilization

4.2 Productivity enhancement on sandy and saline-sodic soil under semi-arid conditions

4.3 Erosion control on extreme acid sulfate soils

4.4 Protection of flood refuge communities or people clusters

4.5 Protection of farm infrastructure

5. OTHER USES

5.1 Handicraft

5.2 Roof thatch

5.3 Mud brick making

5.4 Strings and ropes

5.5 Ornamentals

5.6 Oil extraction for medicinal purposes and cosmetics

6. REFERENCES

7. LINKS

1. INTRODUCTION

Years of experience in many countries have confirmed that, even if farmers have adopted vetiver to conserve soil, that application was not necessarily the main reason that they initially adopted it. In Venezuela, for example, vetiver was first grown to supply handicraft material. After crafts people embraced the dried leaves because they were beautiful and easy to weave, vetiver’s soil conservation application was easier to introduce. Vetiver hedges were first appreciated in Cameroon as a barrier to keep snakes out of yards, and, in other places, vetiver was employed to delineate boundary lines (tree-marked boundaries were susceptible to challenge). In still other places the first reason vetiver was accepted was because it controlled pests in stored beans, and stem borers in maize (South Africa). This folio addresses several vetiver applications that are most commonly practiced by farmers.

2. SOIL AND WATER CONSERVATION

2.1 Soil and water conservation principles

The purpose of soil conservation practice is to control or reduce soil erosion caused by water and wind. In the case of water erosion, soil particles are first dislodged by excessive volume and/or high velocity of an overland flow of water. Wind erosion results from high wind velocity at ground level on bare surface.

Therefore the main goals of water erosion control practice are to protect the soil surface from being dislodged by the impact of the raindrops, to reduce the volume of runoff water using vegetative covers, and to control or lower the overland flow velocity. Contour/diversion banks (terraces) by design, divert runoff to a safe outlet, or waterway, or the drainage network. Vegetative barriers such as vetiver hedges planted across the slope or on the contour control the runoff, spreading it out and slowing it down as it slowly filters through the hedge. Since the erosive power of both water and wind erosion is proportional to the flow velocity (the speed of the downhill water and the force of the wind), the main principle of soil conservation is to reduce the speed of water and air. Correctly installed, vetiver hedges effectively control both water and wind erosion.

The objective of water conservation practice is to increase water infiltration to the soil body. This goal can be achieved most readily using vegetative cover, particularly vegetative hedges. When planted across the slope or on contour lines, dense vetiver hedges form a slowly permeable barrier that spreads runoff water and reduces its velocity. This allows more time for soil to absorb the water and the hedge to trap sediment.

2.2 Characteristics of vetiver suitable for soil and water conservation practices.

Unique characteristics of vetiver that are particularly important for soil and water conservation are:

  • The soil-binding root system: deep, penetrating, massive, fibrous roots.
  • Erect, stiff stems form a dense hedge, effectively retarding and spreading water flow, reducing its erosive power.
  • Tolerance to all kinds of adverse soil conditions and poor soils, including acid sulfate, alkaline, saline and sodic environments.
  • Ability to withstand prolonged submergence.
  • Adaptability to a wide range of climatic conditions; growing both in the colder mountainous areas of the north and in extremely dry conditions in dunes of central coastal areas.
  • Easy vegetative multiplication.
  • Sterility; it flowers, but produes no seed. Since vetiver (C. zizanioides) has no above or underground stems, it remains where it is planted and does not become a weed. Unlike C. nemoralis, which is indigenous to Vietnam and produces fertile seeds, C zizanioides is sterile and has a massive root system. A seperate folio fully describes the significant differences between the two species.
  • Its vertical root system, with very little lateral root growth. This ensures that the plant, when intercropped, does not generally compete with cash crops for nutrients and water.

More detailed characteristics of the vetiver plant are in a seperate folio. This folio focuses on the important role in farming played by the first two characteristics: Vetiver’s soil-binding root system and its ability to form dense hedgerows. Vetiver’s strong root system is unmatched by any other plant used for on-farm erosion control. On flat lands and on gully floors, where the velocity of raging floodwater can be devastating, vetiver’s deep, strong roots prevent the plant from dislodging. This grass can withstand extremely strong currents.

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Photo 1: Strong current on this waterway in Australia flattened native grasses, leaving the vetiver hedge unaffected; its stiff stems reduced water velocity and its erosive power.

In addition to reducing surface erosion on sloping land, vetiver’s massive root system also contributes to slope stability. As described in another folio the deep, fibrous roots reduce the risk of landslide or collapse.

Vetiver’s stiff stems form a dense hedge that reduces water velocity, allows more time for water to infiltrate the soil, and, where necessary, diverts surplus runoff water. This is the principle of ‘flow-through’ erosion control for farms on the flood plains as well as on steep slopes in high rainfall areas.

2.3 Contour banks or terrace systems versus the vetiver flow-through system.

A review conducted for the World Bank compared the effectiveness and practicality of different soil and water conservation systems. It found that constructed measures must be site-specific and require detailed and accurate engineering and design. Furthermore, all hard systems require regular maintenance. Most evidence also suggests that constructed works reduce soil losses, but do not reduce runoff significantly. In some cases, they have a negative impact on soil moisture (Grimshaw 1988). On the other hand, when planted across the slope or on the contour, the vegetative conservation system forms a protective barrier across the slope that slows the runoff water and hoards sediment deposits. Since the barriers only filter the runoff and often do not divert it, water seeps through the hedge, reaching the bottom of the slope at lower velocity without causing any erosion and without being concentrated in any particular area. This is the flow-through system (Greenfield 1989), a sharp contrast to the contour terrace/waterway system in which runoff water collects by the terraces and is diverted quickly from the field to reduce its erosive potential. Since all runoff water is collected and concentrated in waterways where most erosion occurs on agricultural lands, particularly sloping lands, this water is forever lost from the field; and also unavailable for groundwater recharge. The flow-through system, on the other hand, conserves water and dispenses with the need for waterways. Figure 1.

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Figure 1: Above left: contour bank; below left: banks divert the water; above right: Vetiver hedges create banks or terraces over time; below right: Vetiver hedges slow the runoff to increase infiltration, and the water remains in the field (Greenfield 1989)

This water conservation practice is very important in low rainfall regions such as the Central Highlands and Central Coastal Vietnam. Ideally, species to be used as barriers for effective erosion and sediment control should have the following features (Smith and Srivastava 1989):

  • Form an erect, stiff and uniformly dense hedge that offers high resistance to overland water flow, and have extensive and deep roots that bind the soil and prevent rilling and scouring near the barrier.
  • Survive moisture and nutrient stress and re-establish top growth quickly after rain.
  • Result in minimum loss of crop yield (the barrier should not proliferate as a weed, not compete for moisture, nutrients and light, and not host pests and diseases).
  • Require only a narrow width to be effective.
  • Supply materials that have economic value to farmers.

Vetiver exhibits all of these characteristics. Uniquely, it thrives in arid and humid conditions, grows under some extreme soil conditions, and survives wide variation in temperature (Grimshaw 1988).

2.4 Application on flood plains

VS is an important tool to control flood erosion in all the flood plains of major rivers in Vietnam. Its use is not restricted to the Red River Delta in the north and Mekong delta in the south. Its application is particularly important to central coastal provinces, where flash flooding regularly occurs with devastating effects, such as the case of the Lam River flood plain in Nghe An province.

Vetiver hedges on flood plains:

  • Reduce flow velocity that can lodge crops, and the run off’s erosive power.
  • Trap fertile alluvial soil on site, which maintains the fertility of the plain.
  • Increase water infiltration in low rainfall regions such as Ninh Thuan province.

Strip cropping uses a “flow-through” system similar to that provided by vetiver hedges, but does not prevent crop lodging, as it does not reduce the speed of the runoff. Unlike vetiver hedges, this method requires a strict sequence of crop rotation, so it cannot be implemented during drought because crops cannot be planted. Strip cropping has been used effectively on the flood plains of the Darling Downs region in Australia to mitigate floodwater damage to crops and to control soil erosion on low gradient lands subject to deep overland flooding.

In a large field trial at Jondaryan (Darling Downs, Queensland, Australia), six rows of vetiver totalling more than 3000m (900 linear feet) were planted on the contour at 90m (180 feet) spacing. These rows provided permanent protection against floodwaters. Data collected from a small flow over the site shows that the hedges reduce significantly the depth and resulting energy of water flowing through the hedges. At a low depression, a single hedge trapped 7.25 tons of sediment. Results over the last several years, including several major flood events, confirm that VS successfully reduces flood velocity and limits soil movement, with very little erosion in fallow strips (Truong et al. 1996, Dalton et al. 1996a and Dalton et al. 1996b). This trial demonstrates that VS is a viable alternative to strip cropping practices on Australia’s flood plains.

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Photo 2: Left: fertile sediment remains as floodwater passes the vetiver hedge; right: a healthy crop of sorghum survives flooding on the flood plain of the Darling Downs, Australia.

2.5 Application on sloping land.

In India on crop land with 1.7% slope, vetiver contour hedges reduced runoff (as percentage of rainfall) from 23.3% (control) to 15.5% and soil loss from 14.4 t/ha to 3.9 t/ha, and increased sorghum yield from 2.52 t/ha to 2.88 t/ha over a four-year period. The yield increase was attributed mainly to in situ soil and moisture conservation over the entire toposequence protected by the vetiver hedge system (Truong 1993). Under small plot conditions at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), vetiver hedges were more effective in controlling runoff and soil loss than either lemon grass or stone bunds. Runoff from the vetiver plots was only 44% of that of the control plots on 2.8% slope and 16% on 0.6% slope. Average reductions of 69% in runoff and 76% in soil loss were recorded from vetiver plots, compared to control plots (Rao et al. 1992).

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Photo 3: Vetiver planted on a very steep slope for soil and water conservation on a tea plantation in India (P Haridas).

In Nigeria, vetiver strips were established on 6% slopes at the end of 20m (60’) runoff plots for three growing seasons to assess their effects on soil and water loss, soil moisture retention and crop yields. Results showed that vetiver stabilized soil and chemical conditions within the entire 20m (60’) distance behind the strip. Under vetiver management, cowpea yields were increased between 11 and 26%, and maize increased about 50%. In comparable 20m runoff plots without vetiver (control), soil loss and runoff water were 70% and 130% higher, respectively. Vetiver strips increased soil moisture storage between 1.9% and 50.1%, depending on depth. The nutritive content in eroded soils on the control plots was consistently poorer than on vetiver plots, which also enhanced Nitrogen use efficiency by about 40%. This research demonstrates the usefulness of vetiver hedges as a soil and water conservation measure under Nigerian conditions. (Babola et al. 2003).

Similar results have been reported on a range of slopes, soil types, and crops in Venezuela and Indonesia. In Natal, South Africa, vetiver hedges have increasingly replaced contour banks and waterways on steep sugarcane lands, where farmers have concluded that the vetiver system is the most effective and low-cost form of soil and water conservation in the long term (Grimshaw 1993). A cost-benefit analysis conducted on the Maheswaran watershed in India considered both engineered structures and vetiver vegetative barriers. The vetiver system was adjudged more profitable even during its initial stages due to its efficiency and low cost (Rao 1993).

In Australia, R&D over the last 20 years has confirmed overseas findings, particularly vetiver’s effectiveness in soil and water conservation, gully stabilization, degraded land rehabilitation, and trapping sediment in waterways and depressions. In addition to these applications, vetiver has proven its versatility in:

  • Flood erosion control on the flood plains of the Darling Downs.
  • Erosion control in acid sulfate soil.
  • Contour bank replacement in steep sugar cane lands in North Queensland.

In Vietnam most of the on-farm experience with the Vetiver System was gained from ‘the cassava project’ (a Nippon Foundation project: ‘Enhancing the Sustainability of Cassava-based Cropping Systems in Asia’, in China, Thailand and Vietnam, 1994-2003), implemented in collaboration with Thai Nguyen University of Agriculture and Forestry (TUAF), National Institute for Soil Fertility (NISF), and Viet Nam Agricultural Science Institute (VASI, now VAAS). This project worked with farmers in northern mountainous areas in Yen Bai, Phu Tho, Tuyen Quang, and Thai Nguyen, in mountainous parts of Thua Thien Hue province, and the southwest. Note: Cassava (Manihot esculenta) is one of the most important staple crops in humid tropical regions, but as a tuber crop typically planted in monoculture it is one of the most erosive crops in the developing world. Hence the importance of promoting more sustainable Cassava production systems. In this project farmers tested several combinations of measures including:

  1. Intercropping (e.g. contour farming with groundnut).
  2. Introduction of improved planting material (low-branching varieties to reduce impact of rain) combined with increased (organic and chemical) fertilization.
  3. Anti-erosion hedgerows. The application of VS proved to be among the most effective measures to reduce soil loss (see CIAT cassava project).

2.6 Effects on Soil Loss

While reducing soil loss has its own merit, keeping fertile soil on-farm, farmers ultimately judge its importance. When their farm soils are deep, farmers may not value soil conservation because it requires work and occupies valuable farmland. However, where slope farming is more intensive, and farmers apply manure and/or chemical fertilizer, then the positive effect of vetiver is not just about reducing soil loss, but also about retaining soil fertility and preventing surface runoff (Truong and Loch, 2004). In wetter areas, vetiver’s deep, extensive root system has an additional advantage: it absorbs soluble nutrients that otherwise would be lost to deeper, unreachable layers of the soil. These nutrients return to the soil when vetiver grass is cut and used as mulch hence these nutrients can be recycled.

In the mountainous regions of northern Vietnam, Tephrosia and wild pineapple have traditionally been used as hedges (sometimes in combination with terracing) to reduce soil loss. However, wild pineapple’s effectiveness is quite low. Its thick stems create mounds that can even increase erosion by concentrating and forcing water through tight spaces between the mounds. Tephrosia is effective only as long as the plant remains established; it dies after two to three years. On moderate slopes, vetiver hedges are a welcome alternative to traditional terracing, which is often labour intensive.

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Photo 4: Difference in soil loss between vetiver (left) and Flemingia congesta (right), a legume. Note differences in soil collction trap.

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Photo 5: Soil trapped behind a vetiver hedge in Dong Rang, northern Vietnam. It also provides in-situ mulch, stops runoff and erosion, and reduces the slope by forming natural terraces.

2.7 Design and extension: farmers’ considerations

Using vetiver to control on-farm soil erosion has made one thing clear: farmers consider many factors before deciding whether and how to use vetiver (Agrifood Consulting International, March 2004). Research farmers (well-off farmers who were subsidized to conduct the trial) shed some light on farmers’ reasoning. Among their concerns, adoption of improved plant varieties and chemical fertilizer was highest. Their priorities and willingness to adopt vetiver as the primary soil conservation method were different from other, non-subsidized farmers.

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Photo 6: Vetiver controls erosion on a coffee plantation in the Central Highlands.

Once farmers understand vetiver principles, and have the opportunity to assess the short-term and long-term impact of VS, they are much more inclined to adopt it. Hence, it is important to place farmers at the centre of the approach, and anticipate that each will adjust the guidelines (e.g. recommended spacing) to fit his own circumstances. Knowing this, the field worker will be better able to advise the farmer to assure the success of the system. The use of subsidized inputs or other material incentives for farmers to collaborate in VS trial and adoption is discouraged, since it will undermine the repeatability of results.

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Photo 7: Vetiver hedges protect organic school garden on 50% slopes (East Bali Poverty Project).

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Photo 8: Making soil loss visible (CIAT cassava project) with and without vetiver. Note difference in rainfall runoff. Less than half in the furthest trap with vetiver protection.

The following checklist for feasibility of large-scale adoption of Vetiver System for Soil and Water Conservation:

A. How important is the soil erosion problem?

  • How deep is the soil profile?
  • How visible is soil loss to farmers on-site or downstream?
  • What is the extent or value of the soil loss? If fertilizer has been applied then farmers are more willing to make an effort to protect their investment, and resist loss through runoff or leaching to deeper layers (e.g. deep-rooted vetiver can recover soluble Nitrogen that quickly leached to unreachable lower layers)?
  • Given slope gradient and soil texture, how erosion-prone is the soil?
  • How does VS compare with other available erosion control methods (e.g. contour ridging, stone contour lines, plastic mulch, and plant varieties that are low-branching, have a fast closing canopy)?

B. How important is the cropping system, compared to other parts of the farm? Farmers are more interested to invest in conservation practices that produce a profitable crop:

  • What is the relative value of the piece of land (willingness to invest labour, money), and what is the general position of the farmer? How much labour/money can he/she invest in this plot? What compete with her/his time and money (e.g. paddy land or off-farm labour)?
  • Is the farmer sufficiently sure of land tenure to justify efforts improving it?
  • Does the distance from homes to the fields justify labour investment?
  • Can the farmer use vetiver in complementary applications (see next chapters)?
  • Is there enough nursery space to propagate vetiver, or otherwise obtain it?
  • What policies militate against applying soil and water conservation measures?
  • What ecological limitations affect the use of vetiver? (e.g. Vetiver does not tolerate shade; once established, however, shade is less of a problem).

Farmers are urged to test, compare and combine Vetiver System with other soil and water conserving practices.

Photo 9. A 2007 Google Earth image of a part of Fiji that John Greenfield planted with vetiver hedgerows in the 1950s’. The hedgerows are still there (red arrows) after 50 years.

3. OTHER MAJOR ON-FARM APPLICATIONS

3.1 Crop protection: stem borer control in maize and rice (and sugar cane)

Stem borers attack maize, sorghum, rice and millets in Africa and Asia. The moths lay their eggs on the leaves of the crop. Professor Johnnie van den Berg, entomologist, (School of Environmental Sciences and Development, Potchefstroom University, South Africa.) found that the moths prefer to lay eggs on the leaves of vetiver planted around the crop instead of on the maize or rice crop itself. Given the option, about 90% of the eggs are deposited on vetiver instead of on the crop.

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Photo 10: Stem borers (Chilo partellus).

Because vetiver leaves are hairy, the larvae that hatch on them cannot move around easily. The larvae fall off the plant and die on the ground, resulting in very high mortality, about 90%. Vetiver also harbours many helpful insects that are predators of pests that attack crops. In cooperation with Dr. van den Berg, Can Tho University is currently studying the practical application of this effect on rice. Preliminary results are very promising. Van den Berg also reports that the sugar cane borer, Eldana saccharina (in some countries such as India Chilo partellus prefers to lay its eggs on vetiver. In India Chilo partellus also is found in cane. Vetiver grass hedgerows provide very good habitat for beneficail insects such Chrysopidae sp. and other beneficail insects. Vetiver alone is not enough to control pests and must be part of an overall IPM package that manages crop health.

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Photo 11: (left) Vetiver’s hairy leaves make it an inhospitable host; stem borer larvae drop off and die on the ground.

 

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Figure 2: The Push-Pull system: Vetiver attracts the insect to lay eggs where they have little chance of survival.

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Photo 12: Maize stem borer control (Zululand, South Africa).

3.2 Animal feed

Vetiver leaves are readily eaten by cattle, goats and sheep. Table 2 compares vetiver’s nutritional values to those of other subtropical grasses in Australia. Young vetiver grass is quite nutritious, actually comparable to mature Rhodes and Kikuyu grass. However, the nutritional value of mature vetiver grass is low, and it lacks crude protein.

A study in Vietnam (Nguyen Van Hon, 2004) shows that young vetiver grass can partially replace mature Brachiaria mutica grass as feed for growing goats.

Vetiver leaves are generally useful by-products of soil and water conservation measures. Vetiver leaves are nutritious when cut (pruned) at intervals between one and three months, depending on climatic conditions. Their nutrient content, like many tropical grasses, varies according to season, growth stage and soil fertility. In India when vetiver is chopped by a manual forage chopper domestic buffaloes find the grass totally palatable.

Table 2: Nutritional values of Vetiver, Rhodes and Kikuyu grass, Australia

Analytes

Units

Vetiver grass

Rhodes

Kikuyu

Young

Mature

Old

Mature

Mature

Energy (ruminant)

kCal/kg

522

706

969

563

391

Digestibility

%

51

50

-

44

47

Protein

%

13.1

7.93

6.66

9.89

17.9

Fat

%

3.05

1.30

1.40

1.11

2.56

Calcium

%

0.33

0.24

0.31

0.35

0.33

Magnesium

%

0.19

0.13

0.16

0.13

0.19

Sodium

%

0.12

0.16

0.14

0.16

0.11

Potassium

%

1.51

1.36

1.48

1.61

2.84

Phosphorus

%

0.12

0.06

0.10

0.11

0.43

Iron

mg/kg

186

99

81.40

110

109

Copper

mg/kg

16.5

4.0

10.90

7.23

4.51

Manganese

mg/kg

637

532

348

326

52.4

Zinc

mg/kg

26.5

17.5

27.80

40.3

34.1

When vetiver is used for other purposes, fodder may prove an added value. After an extremely harsh winter in Quang Binh province, vetiver was the only green fodder available; the cold had killed the other grasses. Further, vetiver grass growing on pig farm waste contains high contents of crude protein, carotene and lutein, relatively lower contents of Ca, Fe, Cu Mn and Zn, and acceptable levels of heavy metal, Pb, As and Cd (Pingxiang Liu 2003).

Vetiver can grow under very high levels of nitrogen (as much as 10,000 kg of N per ha). Thus when vetiver is an an integral part of a constructed wetland for waste treatment (animal and human) it will yield over 100 tons of dry matter per ha.

Vetiver will also grow well on salinized soils, if the area has a high ground water table as is the case of parts of India's Haryana and Punjab States, there is a potential of dry matter yields of 70 tons per ha of forage.

Vetiver's forage potential would benefit from further research both in the management of the grass as a forage and the identification of cultivars that are more suitable as a forage.

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Photo 13: Left: buffalo graze on vetiver bordering dike; right: cattle eat young vetiver.

3.3 Mulch to control weeds and conserve soil water

Given silica content higher than other tropical grasses, such as Imperata cylindrica, vetiver shoots take a longer time to break down. This makes vetiver ideal for use as mulch and roof thatching (as thatch it does not harbour insects).

Weed control: When spread evenly on the ground, whole or desiccated vetiver leaves form a thick matt that suppresses weeds. Vetiver mulch successfully controls weeds in coffee and cocoa plantations in the Central Highlands and tea plantations in India .

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Photo 14: Vetiver controls erosion and its mulch suppresses weeds in coffee plantation in the Central Highlands.

Water conservation: The thick cover of vetiver mulch increases water infiltration and reduces evaporation, particularly important under the hot, dry conditions of the coastal provinces like Ninh Thuan. It also protects the soil surface from the impact of raindrops, a major cause of soil erosion. Research in India, Nigeria and Thailand and other countries demonstrate improvement in crop yields - see para 2.5.

As mentioned earlier vetiver hedgerows reduce rainfall run off significantly. Much of this reduction finds its way to the groundwater as recharge. This is a very important aspect as there is plenty of evidence that this improved recharge results in increased and prolonged stream flow, subsurface recharge of farm ponds, and improved spring flows - all important to small farmers and the community as a whole.

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Photo 15: Vetiver mulch controls weeds in a tea plantation, southern India (P Haridas).

3.4 Vetiver seedlings.

Due to the growing demand for vetiver in VS applications for non-agricultural sectors the production of vetiver seedlings (slips) as a marketable product is an expanding actuality. Vetiver slips are easy to produce in very large quantities. The most common forms of production are bare rooted or containerised. Under good conditions (adequate water and nutrients) it is quite possible to produce at least 500,000 slips (with three tiller each) per ha per year. In most countries this would gross at least US $15,000 per ha. It is therefore to the benefit of farmers if farmers groups or their representatives lobby other sectors to use the Vetiver System for slope protection, pollution control, and disaster mitigation. In countries, such as India, Indonesia, and Haiti where vetiver is grown for the aromatic oil, the sale of plant material (only a small portion of the root is sacrificed when slips are produced) should prove a very good bi-product, and would make, what is often a marginally business a lot more profitable at very little extra cost. It is conservatively estimated that in south India 15-30 billion slips a year might be available as a biproduct from vetiver oil producing farms.

Photo 16: A potential source of plant material - a 15 ha aromatic oil farm in Tamil Nadu with a potential of 7.5 million slips a year (Bharat Singh).

4. FARMLAND REHABILITATION AND PROTECTION OF FLOOD REFUGE COMMUNITIES

4.1 Sand dune stabilization

Sand dunes occupy more than 70,000 ha (172,974 acres) along the coast of Central Vietnam. These dunes are highly mobile due to strong wind and highly erodible during heavy rains. Without stabilization, the sand invades valuable farmland, destroying crops, and clogging rivers and streams. Local farmers suffer enormous losses as a consequence. Traditional methods of stopping dune movement, which include the planting Casuarinas trees and wild pineapple, and constructing small dikes made of sand, are ineffective. Planting vetiver hedges offers the best solutions to date.

The following case study illustrates the problem: In Quang Binh Province the toe slope of a sand dune was badly eroded by a meandering stream that served as a natural boundary between the dunes and a Forest Enterprise nursery. The stream undercutting the dune foot slope moved the sand, depositing it on irrigated farms downstream. The farmers, who tried to divert the sand-stream with dikes made of dune sand, succeeded only in transferring the problem to other farms. The situation created conflicts among farmers, and, since the stream had been diverted from its nursery toward the dune, with the Forestry Enterprise.

Four rows of vetiver were planted in contour lines on the slope of the sand dune, starting from the edge of the stream. After only four months, the plantings had formed closed hedgerows and stabilized the sand dune toe. The Forestry Enterprise was so impressed with this result that it mass planted the grass on other sand dunes and even used it to protect a bridge abutment. The grass further surprised local people by surviving the coldest winter in ten years, when the temperature plummeted below 10ºC, a cold spell that forced farmers to twice replant their paddy rice and Casuarinas. After two years, local species such as Casuarinas and wild pineapple re-established themselves between the vetiver rows. Under the shade of the native trees, the grass itself faded away, having accomplished its mission. The project proves again that vetiver can withstand very hostile soil and climatic conditions.

Several issues should be considered when addressing dune slope protection:

1. Assessing and planning together with local communities is very important a community can:

  • provide valuable ideas during planning.
  • contribute financially.
  • provide labour for implementation.
  • protect and maintain the plantings.
  • benefit from employment associated with the establishment and maintenance of the site.

2. Training local people: When teaching local people about vetiver multiplication, planting and maintenance, provide instruction about its other uses (fodder, handicraft).

3. Propagation: Local nurseries can be contracted to propagate vetiver and supply bare root slips for installation.

4. Maintenance and monitoring: The local community can monitor and maintain the plantings. Dry sands shift, sometimes burying or even washing away the young grass, so maintenance at early stages is important. Photo 17 and 18 Community vetiver hedges on dunes in Le Thuy district and Quang Binh province.

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Photo 17: Early April 2002 – vetiver one month after planting. Note: Mulch was put above the top row (left). Mid October 2002 (seven months): Casuarinas has become re-established between vetiver rows (right).

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Photo 18: Shows the way the local community extended the practice, with support from local foresters. February 2003: hedgerows established in October 2002 survived the coldest-ever winter in Quang Binh.

Vetiver is equally effective in reducing blowing sand. For this use, the grass should be planted across the wind direction, especially in troughs between sand dunes, where wind velocity typically increases. This use has been tested on coastal dunes in Senegal (Photo 19a and b), as well on Pintang Island, off the East China coast.

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Photo 19a: Vetiver protects dunes at a beach resort in Senegal.

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Photo 19b: Pingtang Island, China from wind erosion. Also forms a windbreak to protect young plants.

4.2 Productivity enhancement on sandy and saline sodic soil under semi-arid conditions.

In south-central Vietnam, Ninh Thuan and Binh Thuan are two coastal provinces that share a peculiar climatic condition. Although both are situated on the coast, they experience semi-arid conditions, with annual rainfall between 200-300mm (8-12”). This results in an extreme shortage of fresh water for cropping and animal husbandry.

The “soil” of the coastal dune is saline, alkaline, and sodic, with a thin compacted gypsum (sodic-petrocalcic) layer just under the topsoil. Agricultural production in the region is very limited, due in part to the poor soil conditions (the gypsum layer effectively prevents roots from penetrating into the more humid layer underneath) and in part to the lack of rainfall. The coastal dune is also prone to wind erosion and water erosion when it rains, so it yields very sparse vegetation and fodder for livestock. These factors contribute to extreme hardship and poverty in the local population.

From 2003 to 2005, Professor Le Van Du and his students from Ho Chi Minh City Agro-Forestry University planted vetiver on these saline sodic soils to determine whether VS could improve the productivity of farms in desert-like conditions. They learned that, once established under initial irrigation, vetiver grew exceptionally well. During the first two months, vetiver grew two to three times faster than any other crop, yielding a fresh biomass of 12 tons on non-saline sandy soils (96% sand) and 25 tons on alkali-sodic soils. In three months, its roots penetrated 70 cm (26.5”), through the compacted gypsum layer, reaching ground moisture that local maize, grapes, and other plants could not reach. The scientists noted a great improvement in soil fertility after only three months, specifically that soluble salt and pH had been greatly reduced. Although soil pH had hardly changed after three years of grape cultivation, following the vetiver installation soil pH declined up to 2 units from the surface layer to a depth of 1m (3’), and dissolved salt content. The reduction in sodium content by more than half dramatically improved the productivity of local crops such as corn and grapes.

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Photo 20a: Vetiver roots penetrated compacted gypsum barrier to tap ground water and flourished; without irrigation corn and grape died.

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Photo 20b: Left: Sandy soil in its original state; right: the same soil, now used for a vineyard, following rehabilitation using vetiver mulch.

4.3 Erosion control on extreme acid sulfate soils

Developing agriculture and aquaculture in an acid sulfate soil region requires an effective and stable irrigation and drainage system. Residents in these areas commonly use local soil (high clay, low pH, high toxicity) to build infrastructure, which is susceptible to soil erosion because it cannot support most vegetation. Since acid sulfate zones are low in topography and subject to annual flooding, local communities suffer extreme hardship.

Found in different regions, the soils share common characteristics: extreme acid sulfate, pH between 2.0 and 3.0 in the dry season, and high levels of Al, Fe, and SO42. The high clay content of the soil causes it to crack as it dries, resulting in large holes that let in water, and cause erosion during the rainy and flood seasons. As a consequence, very few endemic plants can establish and survive during the dry season, including those considered to be locally tolerant species.

Vetiver has stabilized embankments and controlled canal bank erosion at five sites located on extreme acid sulfate soils in Vietnam: one flood protection dike (protecting a people cluster or flood-refuge community) in Tien Giang province, three in Long An provinces, and one section of a flood protection dike near Ho Chi Minh City.

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Photo 21: Before (left) and after (right) vetiver installation in extreme acid sulfate soil on an embankment in Tien Giang province, Vietnam.

Planted in polybags, vetiver readily established itself in the compromised soils. Although no vetiver survived when planted as bare root slips directly into fresh acid sulfate soil, more than 80 percent of bare root slips survived and grew normally in the same soil when a small amount of lime, good topsoil, or manure was first added to the furrows.

The following results were recorded:

  • Over four months, once it was established, vetiver markedly reduced soil loss by erosion. Bare canal banks lost soil at a rate of 400-750 tons/ha, compared with only 50-100 tons/ha on a channel embankment protected by vetiver.
  • After 12 months, soil loss had become negligible.
  • The banks were completely stabilized when vetiver was trimmed to 20-30cm (8”-12”) and the shoots were used as mulch covering the bare area of the bank (Le van Du and Truong, 2006).

4.4 Protection of flood-refuge communities or people clusters

Major flooding occurs annually in several provinces of the Mekong Delta in southern Vietnam. These floods are usually up to 6-8m (18-24’) deep and can last as long as three to four months. As a result houses are flooded every year unless they are located on land protected by major dike systems. Subsistence farmers have to rebuild their homes every year, at great personal sacrifice.

To overcome this problem, local governments designate as Flood-refuge Communities or People Clusters areas of relatively high ground that have been augmented with soil from the surrounding land. Although these constructed areas are high enough to escape annual prolonged floods, their banks are highly erodible and require protection from the strong currents and waves generated during the flood season. Vetiver hedgerows have been highly effective in protecting these clusters against flood erosion, with the added benefit of treating community effluent and wastewater during the dry season.

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Photo 22: Left: Flood-Refuge Community (or People Clusters) in Tan Chau District, An Giang Province; (right) the bank of the Cluster.

4.5 Protection of farm infrastructure

VS is widely used to protect farm infrastructure by stabilizing farm dams, aquaculture dikes, and rural roads, among other applications. Photo 23 shows vetiver reducing the impact of a gully that drains water from the seasonally flooded farm area (background) towards the river. Since the gully also threatens the shrimp pond (right), vetiver also protects the banks of the pond, especially in the area where the farmer drains the water from the pond into the gully, the most vulnerable place. Vetiver stabilizes slopes bordering dirt roads and rivers, preventing landslides in mountainous regions and riverbank erosion on the flood plain. In the Philippines and India, vetiver is also widely used to stabilize the narrow dikes that separate paddy fields on sloping land. This planting reinforces the sides of these dikes as it reduces the width of the dikes, which increases the area available for cropping. An added bonus is that the planting will provide fodder for cattle and buffalo during the dry season.

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Photo 23: Vetiver protects a shrimp pond near a natural gully that drains water into a river (Da Nang province); this model was established as part of the first vetiver project financed by the Royal Netherlands Embassy in Vietnam.

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Photo 24: Vetiver, installed in a cross-hatched pattern, protects shrimp pond dikes in Quang Ngai.

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Photo 25: The right section of this rural road in Quang Ngai is protected by vetiver; the left section is unprotected.

Table 3 above gives some indication of the different uses and applications of vetiver and their realtionship to bothe environmental and economic benefits. As can be seen they are very much interlinked, and the potential for sector wide linkage to the farming community is high.

5. OTHER USES

5.1 Handicraft

Rural communities in Thailand, Indonesia, Philippines, Latin America, and Africa are using vetiver leaves to produce high-quality handicrafts, an important means of generating income. “Vetiver Handicrafts in Thailand,” published by the Pacific Rim Vetiver Network (1999), is a well-illustrated, practical guidebook to this use. References at the end of this Part provide details on how to obtain this guide. The Royal Development Projects Board of Thailand offers free training on vetiver handicraft-making to foreign participants.

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Photo 26a: Typical Thai handicrafts supported by the Royal Development Projects Board of Thailand.

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Photo 26b: Typical Thai handicrafts supported by the Royal Development Projects Board of Thailand.

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Photo 27: Vetiver handicrafts from Mali made by weaving vetiver leaf into a “ fabric” for pillows and throws.

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Photo 28a: Vetiver handicrafts made by a Venezuelan women’s cooperative supported by the POLAR Foundation.

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Photo 28b: Vetiver handicrafts made by a Venezuelan women’s cooperative supported by the POLAR Foundation.

5.2 Roof thatch

Vetiver leaves last longer than Imperata cylindrica, at least twice as long according to farmers in Thailand, Africa and the South Pacific Islands, making them particularly suitable for use in bricks and as thatching. Users report that the leaves repel termites.

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Photo 29: Left to right: Thatched roofs in Fiji, Vietnam and Zimbabwe.

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Photo 30: Roof thatching in Venezuela.

5.3 Mud brick making

Vetiver straw is widely used in Senegal, Africa, to make mud bricks that resist cracking Housing construction in Thailand uses bricks and columns made from clay composite to which vetiver leaves have been added. These building materials have rather low thermal conductivity, which makes the resulting construction comfortable and energy-efficient, as well as a labour-based appropriate technology.

5.4 Strings and ropes

Farmers who grow rice, the main crop of the Mekong Delta, have discovered another use for vetiver leaves as string to bind rice seedlings and rice straw. They prefer vetiver string because it is pliant and tough, even more pliant and stronger than the banana, rush and Nipa palm string commonly used.

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Photo 31: Left: Vetiver reinforces a wooden structure along a river; right: cut vetiver leaves make string for use as rice binding.

5.5 Ornamentals

Mature vetiver has light purple and very pretty flower heads, which can be used as cut flowers, potted plants or landscaping in gardens and other public open spaces such as lakes and parks.

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Photo 32: Vetiver borders a lake in an expensive suburb (Brisbane, Australia).

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Photo 33: Different ornamental applications in Australia, China and Vietnam.

5.6 Oil extraction for medicinal purposes and cosmetics

In Africa, India and South America, vetiver roots are widely used for medicinal purposes, ranging from common cold to cancer treatment. American research confirms that oil extracted from vetiver roots has anti-oxidant characteristics with cancer reduction/prevention applications. In India and Thailand, healing-arts practitioners use vetiver oil extensively in aromatherapy applications because of its documented calming effects.

Table perfumery applications:

  • Pure essential oil (perfume in its own right) - base note with slow evaporation rate (known as Ruh Khus, Majmua).
  • Vetiverol - weak aroma and high solubility in alcohols, renders best fixative and blending qualities.
  • Diluted forms - flavouring, refreshing and refrigerating applications (colognes, toilet waters).

Medicinal aromatherapy:

  • Skin care, CNS benefits
  • Stops nosebleeds and treats bee stings.

Table 3: World production and use of vetiver root oil Chemical composition and applications of vetiver oil.

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6. REFRENCES

Agrifood Consulting International, March 2004. Integrating Germplasm, Natural Resource, and Institutional Innovations to Enhance Impact: The Case of Cassava-Based Cropping Systems Research in Asia, CIAT-PRGA Impact Case Study. A Report Prepared for CIAT-PRGA.

Berg, van den, Johan, 2003. Can vetiver Grass be Used to Manage Insect Pests on Crops? Proc. Third International Vetiver Conf. China, October 2003. Email: drkjvdb@puk.ac.za.

Chomchalow, Narong, 2005. Review and Update of the Vetiver System R&D in Thailand. Summary for the Regional Conference on vetiver ‘Vetiver System: disaster mitigation and environmental protection in Viet Nam’, Can Tho City, Viet Nam, to be held in January 2006.

Chomchalow, Narong, and Keith Chapman, (2003). Other Uses and Utilization of Vetiver. Pro. ICV3, Guangzhou, China, October 2003.

CIAT-PRGA, 2004?. Impact of Participatory Natural Resource Management Research in Cassava-Based Cropping Systems in Vietnam and Thailand. Impact Case Study. DRAFT submitted to SPIA, September 7, 2004.

Greenfield, J.C. 1989. ASTAG Tech. Papers. World Bank, Washington D.C.

Grimshaw, R.G. 1988. ASTAG Tech. Papers. World Bank, Washington.

Le Van Du and P. Truong (2006). Vetiver grass for sustainable agriculture on adverse soils and climate in South Vietnam. Proc. Fourth International Vetiver Conf. Venezuela, October 2006.

Nguyen Van Hon et al., 2004. Digestibility of nutrient content of vetiver grass (vetiveria zizanioides) by goats raised in the Mekong Delta, Vietnam.

Nippon Foundation, 2003. From the project ‘Enhancing the Sustainability of Cassava-based Cropping Systems in Asia’. On-farm soil erosion control: Vetiver System on-farm, a participatory approach to enhance sustainable cassava production. Proceedings from International workshop of the 1994-2003 project in SE Asia (Viet Nam, Thailand, Indonesia & China).

Pacific Rim Vetiver Network, October 1999. Vetiver Handicrafts in Thailand, practical guideline. Technical Bulletin No. 1999/1. Published by Department of Industrial Promotion of the Royal Thai Government (Office of the Royal Development Projects Board), Bangkok, Thailand. For copies write to: The Secretariat, Office of the Pacific Rim Vetiver Network, c/o Office of the Royal Development Projects Board, 78 Rajdamnem Nok Avenue, Dusit, Bangkok 10200, Thailand (tel. (66-2) 2806193 email: pasiri@mail.rdpb.go.th.

Pham H. D. Phuoc, 2002. Using Vetiver to control soil erosion and its effect on growth of cocoa on sloping land. Nong Lam Univ., HCMC, Vietnam.

Pingxiang Liu, Chuntian Zheng, Yincai Lin, Fuhe Luo, Xiaoliang Lu, and Deqian Yu (2003): Dynamic State of Nutrient Contents of Vetiver Grass. Proc. Third International Vetiver Conf. China, October 2003.

Tran Tan Van et al. (2002). Report on geo-hazards in 8 coastal provinces of Central Vietnam - current situation, forecast zoning and recommendation of remedial measures. Archive Ministry of Natural Resources and Environment, Hanoi, Vietnam.

Tran Tan Van, Elise Pinners, Paul Truong (2003). Some results of the trial application of vetiver grass for sand fly, sand flow and river bank erosion control in Central Vietnam. Proc. Third International Vetiver Conf. China, October 2003.

Tran Tan Van and Pinners, Elise, 2003. Introduction of vetiver grass technology (Vetiver System) to protect irrigated, flood prone areas in Central Coastal Viet Nam, final report, for the Royal Netherlands Embassy, Hanoi.

Truong, P. N. (1998).Vetiver Grass Technology as a bio-engineering tool for infrastructure protection. Proceedings of North Region Symposium. Queensland Department of Main Roads, Cairns August 1998.

Truong, P. N. and Baker, D. E. (1998). Vetiver Grass System for Environmental Protection. Technical Bulletin No. 1998/1. Pacific Rim Vetiver Network. Office of the Royal Development Projects Board, Bangkok, Thailand.

Truong, P. and Loch R. (2004). Vetiver System for erosion and sediment control. Proceedings of 13th Int. Soil Conservation Organization Conference, Brisbane, Australia, July 2004.

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