Name: Vetiver grass(Eng), Khus Khus (Urdu/Hindi), Secate violetta (Spanish), Xieng Geng Sao (Chinese).

Family: Gramminae: Chrysopogon zizanioides, C.nigratana, C. nemoralis

Origin:

Chrysopogon zizanioides -- Asia - subcontinent

Chrysopogon nigratana -- Southern Africa

Chrysopogon nemoralis -- South East Asia

Uses:

• On Farm soil and Water Conservation
• Soil and embankment stabilization
• Land Rehabilitation including mining
• River, canal and drain bank stabilization
• Water quality improvement
• Pollution Mitigation
• Aromatic oil from roots for perfume industry
• Thatching,
• Fodder (when properly managed)
• Mulch
• Paper making
• Medicinal
• Greenhouse gas mitigation
• Handicrafts

Habit:

Perennial grass, up to 2 m high, with a strong dense and mainly vertical root system often measuring more than 3 m. It is by nature a hydrophyte, but often thrives under xerophytic conditions.

Climate:

Temperature:

• Mean 18 - 25º C
• Mean coldest month 5ºC
• Absolute minimum - 15ºC
• When ground freezes grass usually dies
• Growth normally starts above 12ºC
• Hot summer temperatures (25ºC +) required for rapid growth. (known to survive temperatures up to 55ºC)

Rainfall:

• as low as 300 mm, but above 700 mm preferable
• will survive total drought, but normally requires a wet season of at least three months. Ideal is well spread monthly rainfall.

Humidity:

• grows better under humid conditions, but does well also under low humidity.

Sunshine:

• difficult to establish under shade, when shade is removed growth recovery is rapid.

Soil:

• grows best on deep sandy loam soils. However it will grow on most soil types ranging from black cracking vertisols through to red alfisols. It will grow on rubble, both acid (ph3) and alkali (pH11) soils, it is tolerant to high levels of mineral toxicities - aluminium, manganese (550 ppm). It will survive complete submergence in water for up to five months. It grows on both shallow and deep soils.

Altitude:

• up to about 2,000 m. above 2000 m growth may be constrained by low temperatures.

Type of user:

Small and large farmers, conservationists, water authorities, highway, railway building site engineers, landfill and waste disposal authorities, mining authorities, aromatic industry, traditional medicine, handicraft makers, landscapers etc.

Rooting Pattern:

Massive root system that is generally vertical and non-invasive to adjoining habitat. Root mass will under good conditions be as much as 3 m deep, and as a mass creates a major below ground barrier. Roots will penetrate weathering "C" horizon rock material, and will follow cracks in otherwise unweathered rock material. Roots are very strong and have the capacity to bind strata together. Average root strength is 75 mpa and roots will improve shear strength of soil by 30 to 40%


Varieties and cultivars:

There are 12 known species of vetiver grass, and many hundreds of different cultivars that exhibit distinctive phenotypic differences which can be exploited by users depending on need. For example thick, stiff stemmed cultivars can withstand high water velocities and probably are best for controlling gully erosion, softer It is recommended that only non fertile cultivars of Chrysopogon zizanioides with origin in South India be used.

Propagation:

By root division. If plenty of planting material is available in the form of existing hedges then these hedges can be divided. In scarcity situations nurseries are required for multiplication purposes. Depending on rainfall and soils 1 slip can produce from 50 -100 new slips in six months. Some cultivars have no flowers, others have flowers, but sterile seeds, others have fertile seeds - the latter type should be avoided. Where end planting sites are very unstable (such as road embankments or gullies with high velocity water flows) it may be more appropriate to raise vetiver in containers, such as 4" polybags. The advantage of this is that there is "instant" growth of the transplanted material rather than initial dieback that occurs with bare rooted plant material.

Planting:

Planting of hedgerows should take place early in the wet season when the soil has been well wetted. 2-3 slips should be planted at each "station", each station should be 10 -15 cm apart. Distance between hedgerows should be at a vertical interval of about 2 m. On flatter land VI may be reduced to 1 meter. Care should be taken to select good quality slips, and they should be planted within three days of lifting from nursery. Better to plant on the day of lifting. Planting slips should not be allowed to dry off and should be protected from the sun. From 2,000 - 3,000 planting slips are required per 100 m of hedge row. Under very dry conditions, > than 700 mm it is better to plant vetiver slips in small "v" ditch or plough furrow to enhance moisture availability at time of planting.

Shade:

Unless a shade tolerant cultivar (rare) is available vetiver should not be planted under shade, later it will withstand shade levels of up to 50%. It will also recover rapidly following the removal of shade.

Fertilizer:

Vetiver will establish better if about 100 kg of FYM is applied per 100 running meters of hedgerow at planting. If FYM is not available di-ammonium phosphate should be applied at about 10 kg per 100 meters. Note one of the advantages of FYM is that it helps to improve moisture availability to the young vetiver plant at time of establishment. FYM and/or DAP should be applied liberally to nursery sites prior to planting of material for multiplication. The use of slow release NPK nuggets for containerized plant material, though not essential, optimises growth rates. There is no need to use fertilizer for maintenance purposes once the hedges have been established.

Yield:

Aromatic oil:

1- 1.5% of the dry weight of the roots that are harvested for distillation

Leaves:

yield levels under fertile and moist (irrigated) conditions can be as high as 100 tons per ha. Normally 15 -30 tons/ha.

Pests and diseases:

Vetiver is generally resistant to most pest and diseases. Vetiver appears to be more susceptible to disease when it is weak and not growing well, particularly on very shallow soils in association with drought conditions. Under the latter conditions, root fungus attacks can be serious. Termites will only attack dead or dying parts of vetiver. If the attack is serious the termite "hills" created can smother living vetiver. Under such conditions annual burning of vetiver hedges will greatly reduce the incidence of termite damage due to burn out of dead plant material. On the other hand recent research indicates that Vetiver has good potential as a "push pull" crop, attracting insects such as stem borer away from adjacent maize crops.

Longevity:

Vetiver is known to live for a long time. The longest recorded period is about 60 years (at Msamfu Research Station in Zambia).

Availability of plant:

Material vetiver can be found in most tropical and semi-tropical countries. Often it has been introduced by aromatic and essential oils industry. National and University herbariums often have vetiver in their collections, and have the local name for it. Traditional medicine users often know of a source of vetiver (though they will not know the grass as vetiver). Vetiver can often be found in countries with established sugar industries, as the latter have used vetiver for conservation purposes over many years. There are well known sources of good quality vetiver in eastern and southern Africa, India, Thailand, Malaysia, Indonesia, China, the Caribbean, Central and South America, and the United States. It is stressed that seedless or sterile vetiver cultivars should be used.

Establishment costs:

The cost of establishment of vetiver depends much on the level of farm labor wages. In most countries where labor rates are about US$ 1 - $1.50 per day vetiver can be established in the field at about US$3 per 100 meter of running hedgerow. Containerized planting can be 10 times higher. Farmers who have a source of vetiver on their farms or nurseries close at hand, can dig and plant between 100 and 200 meters of vetiver per day.

A well managed nursery can produce over 2 million planting slips per ha per year, sufficient to plant 50 km of hedge row.

Impact on soil losses:

Records from most sites where data has been collected indicate that erosion levels can be reduced to less than 3 tons/ha of soil loss per annum. This is an acceptable level.

Impact on runoff reduction:

Records indicate that runoff can be reduced by as much as 60 -70% of recorded rainfall. Variation is quite high, and depends on slope, rainfall event intensity, and potential infiltration rates and water holding capacity of soils at site.

Ground water recharge:

Not many investigations have been undertaken, but it appears that recharge rates of 30% over non protected areas are being achieved where vetiver is used.

Crop Yield Increases:

Research and on-farm data confirms that in the majority of cases there are quite significant yield increases associated with the use of vetiver grass hedges varying from 15 - 60%. Yield increases are variable and are associated with rainfall patterns and soil types. Risk of crop failure is reduced. It should be noted that in most instances does not compete for moisture and nutrients with adjoining crops.

Further Information:

Information on vetiver is available in many countries and on this web site