Vetiver grass plants, vetiveria zizanioides (in Tamil, the word means 'dug up root') have long been known to provide economical protection against soil and water loss, and more recently they have also been found to be useful for water purification. However, the bone of contention is, while other nations have rapidly embraced it, in India its adoption remains rare.
In 1987, noting that soil erosion is the most serious agricultural problem in the world, Richard Grimshaw and John Greenfield, two agricultural scientists of the World Bank decided this had to be tackled on war footing. During their visits to different states of India, they chanced upon the solution they were so eagerly looking for in a sleepy village near Gundlupet in Karnataka. "We learnt from these farmers that they have been successfully growing vetiver against soil erosion for centuries. It reduced rainfall runoff by as much as 70%, recharged groundwater (villages that use vetiver have much higher water levels in their wells), and improved ephemeral stream flow."
In the hilly terrains where tea is grown, soil erosion is a big problem. The tea estates established by the British didn't have permanent soil and water conservation measures. As such, during replanting, a lot of expenditure has to be incurred for this. In the past, our company too spent heavily to construct stonewalls (revetments) across the slope. Depending on the gradient, normally two or three walls (top, middle and bottom) will be needed. On an average, stone revetments for a hectare of tea garden would require 350 man-days. Instead, 100 man-days would be sufficient if you opt for vetiver hedges."
Subsequent studies prompted the World Bank to launch The Vetiver Network (TVN), which has been disseminating vetiver technology to the world with a missionary zeal. Now there are more than 20 vetiver networks in the world and newer ones are being formed every year. In China alone, vetiver is so popular that the country now has a Chinese Vetiver Network and 6 corporations for the implementation of vetiver systems for environmental protection.
Best candidate for 'earth repair' :
What makes vetiver so popular? It's perennial and requires minimal maintenance. It's both xerophyte and hydrophyte. Once established, it can withstand drought, flood and long periods of water logging. It will grow in all types of soil regardless of fertility, pH or salinity. It is highly tolerant to toxic levels of aluminium, manganese, arsenic, cadmium, chromium, nickel, copper, mercury, lead, selenium and zinc. It will grow in a wide range of climates, survives in areas with average annual rainfall between 200 and 6000 millimeters and with temperatures ranging from 1 to 45 degree C. It is a climax plant and therefore even when drought, flood, pests, diseases, fire or other adversity destroys all surrounding plants, vetiver will remain to protect the ground from the onslaught of the next rains. It has a strong fibrous root system that penetrates and binds the soil to a depth of three meters and can withstand the effects of tunneling and cracking.
The vetiver system is low cost and extremely effective system for soil and water conservation, infrastructure stabilization, pollution control, wastewater treatment, mitigation and prevention of storm damage and many other applications.
Vetiver grass, vetiveria zizanioides, is central to all vetiver system based bioengineering and conservation applications. It can be used in the tropics and semi tropics, and areas outside the latter (such as Italy and California that have a Mediterranean climate) where there are hot summers, and winters that do not include permanently frozen soil conditions.
The roots of the grass have an average tensile strength of Mpa 75 (one-sixth the strength of Mild Steel), and improve the shear strength of soil by between 30 and 40%. Engineers liken them to a "living soil nail". (for more details see: http://www.vetiver.com/)
Crutch for rain-fed farmers
Richard Grimshaw, now President of TVN recalls "When I was introducing the vetiver system in areas, I introduced it by saying 'We have a technology that can improve your yields by 15-50%, that is permanent, once established, costs nothing and will drought proof your crops'. Then I go on with the explanation of how vetiver hedges conserve runoff and increase the moisture in the soil. Farmers are not interested in spending money on "soil conservation". Vetiver hedges providing moisture conservation are of course preventing soil erosion; you just don't need to mention it."
Are these vetiver hedges in any way better than contour bunds? "A bund diverts runoff to the drainage network, thus denying the rainfed farm the full benefit of the rainfall it gets. The area immediately in front of the bund rarely gets sufficient moisture for crop growth. The vetiver hedge holds the rainfall back, spreads it out and gives it a chance to soak in to the ground as stored moisture. Excess runoff filters through the hedge and carries on down the slope at greatly reduced speed, but wetting all the ground as nature intended it to do."
"In a particular case in Karnataka," he recalls, "the farmers had planted their Ragi, received six millimeters rainfall, enough to germinate their seed but then no more rain for over a month, the seedlings died. Their neighbors who had planted vetiver hedges retained enough moisture in the soil to carry their plants over and produce very good yields."
"Soil moisture is essential for crop growth", analyses John Greenfield, "So, it is no use talking about the benefits of 'drought tolerant' and especially 'drought resistant' (which don't exist) crop varieties, as without sufficient moisture none of these will survive. Therefore it is essential that the rain fed farmer controls runoff to enhance moisture conservation - controlling runoff also control soil loss. The only efficient way to control runoff is with the use of vetiver hedges."
Apart from its value for soil and water conservation, vetiver can check weed invasion too. It can block the spread of other grasses including some of the world's worst creeping grasses. In Zimbabwe tobacco farmers reportedly plant vetiver around their fields to prevent invasion of other tough grasses. In Mauritius sugar cane growers rely on vetiver to prevent Bermuda grass from penetrating their fields from adjacent roadsides. In High Range, for example, a vetiver plot established at Kundaly in the early 1990s kept Kikyu grass (Pennisetum clandestinum) from creeping in. Obviously establishing vetiver hedges along the periphery of tea fields could prevent invasion of deep rooted tough grass weeds. "
Water ponds and tanks that are being cleaned and desilted would benefit from surrounding vetiver hedgerows to prevent future siltation, and floating platforms of vetiver on the ponds would significantly increase water quality. Springheads can also be very effectively protected by vetiver.
Water purification
One recently discovered attribute of vetiver is its capacity to purify water, and thus to help in wastewater treatment. Vetiveria zizanioides, a species widely present in India, can absorb many heavy metals, nitrogen and phosphorous from water. In studies conducted in China using vetiver to treat effluents from piggery farms, the results were quite encouraging. Using vetiver to purify water bodies is easy, too. Being hydrophyte, the plants don't require a separate medium to grow in water. The only arrangement required to make vetiver plants survive in water properly is a float to maintain the balance between roots and shoot and to make the plant stand erect. Cut pieces of bamboo make a good float.
TVN has been awarding certificates to individuals who have been doing good work and demonstrating a high level of knowledge in specific areas of the vetiver System technology. Only one person from India Mr. Haridas, to get this recognition so far, and is one of 14 persons from around the world.
While more and more countries are embracing vetiver technology, it is quite ironic to see that in India itself, vetiver is a sort of 'touch me not' plant, despite having its origins here! A few months ago, a report in an English daily stated that upon hearing a success story of railroad stabilisation in China courtesy vetiver, Konkan Railways approached the railway authorities of China to know more about this while the technology has in reality originated from our own country.
The link with soil conservation is also a strong motivator. "To get the water stored properly you need a medium, which is the earth - hence our soil too has to be protected from erosion. Let us work on SOS (Save our Soil)".
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