The Vetiver System (VS) is a system of

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

and

water conservation Water conservation aims to sustainably manage the natural resource of fresh water, protect the hydrosphere, and meet current and future human demand. Water conservation makes it possible to avoid water scarcity. It covers all the policies, strateg ...

whose main component is the use of the

vetiver ''Chrysopogon zizanioides'', commonly known as vetiver and khus, is a perennial bunchgrass of the family Poaceae. Vetiver is most closely related to sorghum while sharing many morphological characteristics with other fragrant grasses, such as ...

plant in hedgerows. It is promoted by the Vetiver Network International (TVNI), an international

non-governmental organization A non-governmental organization (NGO) is an independent, typically nonprofit organization that operates outside government control, though it may get a significant percentage of its funding from government or corporate sources. NGOs often focus ...

. The Vetiver System is used in more than 100 countries for soil and water conservation, infrastructure stabilization,

pollution control Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...

waste water treatment Wastewater treatment is a process which removes and eliminates contaminants from wastewater. It thus converts it into an effluent that can be returned to the water cycle. Once back in the water cycle, the effluent creates an acceptable impact on ...

, mitigation and rehabilitation,

sediment control A sediment control is a practice or device designed to keep eroded soil on a construction site, so that it does not wash off and cause water pollution to a nearby stream, river, lake, or sea. Sediment controls are usually employed together with e ...

, prevention of storm damage and other environmental protection applications (through

bioengineering Biological engineering or bioengineering is the application of principles of biology and the tools of engineering to create usable, tangible, economically viable products. Biological engineering employs knowledge and expertise from a number ...

and

phytoremediation Phytoremediation technologies use living plants to clean up soil, air and water contaminated with hazardous contaminants. It is defined as "the use of green plants and the associated microorganisms, along with proper soil amendments and agronom ...

Utility

The

plant, ''Chrysopogon zizanioides'', is the main component to all Vetiver System bioengineering and conservation applications. It can be used in the tropics and semi-tropics, and areas that have a Mediterranean climate where there are hot summers, and winters are temperate. When Vetiver is planted as a

hedgerow A hedge or hedgerow is a line of closely spaced (3 feet or closer) shrubs and sometimes trees, planted and trained to form a barrier or to mark the boundary of an area, such as between neighbouring properties. Hedges that are used to separate ...

across a slope, it forms a dense vegetative barrier that slows and spreads rainfall runoff. Combined with a deep and strong root system, a wide range of pH tolerance (from about pH 3 to pH 11), a high tolerance to most heavy metals, an ability to remove from soil and water large quantities of nitrates, phosphates and farm chemicals, the vetiver plant can be used for soil and water conservation, engineered construction site stabilization, pollution control (

constructed wetland A constructed wetland is an artificial wetland to treat sewage, greywater, stormwater runoff or Industrial wastewater treatment, industrial wastewater. It may also be designed for land reclamation after mining, or as a Flood mitigation, mitigatio ...

s), and other uses where soil and water come together. The variety of vetiver that is promoted for VS applications originates in

south India South India, also known as Southern India or Peninsular India, is the southern part of the Deccan Peninsula in India encompassing the states of Andhra Pradesh, Karnataka, Kerala, Tamil Nadu and Telangana as well as the union territories of ...

, is non-fertile and non-invasive, and has to be propagated by clump subdivision. Its massive, finely structured root system can grow fast - in some applications, rooting depth can reach 10–12 ft (3–4 m) in the first year. This deep root system makes the vetiver plant drought-tolerant and difficult to dislodge by strong current. It has stiff and erect stems, which can stand up to relatively deep water flow. New shoots develop from the underground crown, making vetiver resistant to fire, frosts, traffic and heavy grazing pressure. Vetiver grass is not significantly affected by pests and diseases, nor does it act as a host for pests or diseases that might attack crop or garden plants.

Technique

The basic technique of soil stabilization using vetiver consists of one or more hedgerows planted on the contour. Nursery plants or slips (clumps) of about 3

tiller A tiller or till is a lever used to steer a vehicle. The mechanism is primarily used in watercraft, where it is attached to an outboard motor, rudder post, rudder post or stock to provide leverage in the form of torque for the helmsman to turn ...

s each, are typically planted 4-6 inches (10 – 15 cm) apart on the contour to create, when mature, a barrier of stiff grass that acts as a buffer and spreader of down slope water flow, and a filter to sediment. The development of strong plants and a deep root system requires full sun. Partial shading stunts its growth, and significant shading can eliminate it in the long term by reducing its ability to compete with more shade-tolerant species. Multiple hedgerows may be required for a secure slope stabilization, in which case the separation between rows depends on the slope, soil condition and composition, and the severity of the problem. Typical distances range between three and six feet. Some published guidelines recommend a distance between rows of about 5.7 ft. (1.7 m) for a 30° slope, and about 3 ft. (1 m) for a 45° slope.

Impact

A good hedge reduces rainfall runoff by as much as 70% and sediment by as much as 90%. A hedgerow stays where it is planted and the sediment that is spread out behind the hedgerow gradually accumulates to form a long-lasting terrace. It is a low-cost, labor-intensive technology claimed to have a high benefit/cost ratio. When used for civil works protection, its cost is claimed to be about 1/20 of traditional engineered systems and designs. The variety of vetiver used in the Vetiver System does not have

stolon In biology, a stolon ( from Latin ''wikt:stolo, stolō'', genitive ''stolōnis'' – "branch"), also known as a runner, is a horizontal connection between parts of an organism. It may be part of the organism, or of its skeleton. Typically, animal ...

s or

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

s and does not produce fertile seed. In some countries vetiver has been used to define property lines. The Vetiver System is a developing technology. As a soil conservation technique and, more recently, a bioengineering tool, the effective application of the Vetiver System in large-scale projects that involve significant engineering design and construction requires an understanding of biology, soil science, hydraulics, hydrology and geotechnical principles.

The Vetiver Network International

The Vetiver Network International (TVNI) is an international NGO, with members in over 100 countries promoting the Vetiver System (VS) for a sustainable environment particularly in relation to land and water. Its active members include people working in government, research institutions, international development agencies, NGOs and the private sector and farming communities.

References

* * Chengchun Ke, Ziyuan Feng, Xijing Wu and Figen Tu, ''Design Principles and Engineering Samples of Applying Vetiver Eco-Engineering Technology for Steep Slope and Riverbank Stabilization'
PDF

External links

The Vetiver Network International (TVNI)
- official site for the Vetiver System
The Vetiver System Knol Collection
{dead link, date=July 2016 , bot=InternetArchiveBot , fix-attempted=yes - a collection of scientific documents about the Vetiver System
Information sources for the Vetiver System
- a collection of trusted information sites on the vetiver plant and the Vetiver System Land management