The Soil-Erosion Initiative
Of all vetiver's applications, controlling soil erosion is by far the best understood and furthest advanced. Probably 90 percent of all the work to date has been devoted to this initiative, and the fact that the plant stops soil loss is now abundantly clear. The effect is due largely to the strength of the stems in hedges placed along the contours of hillslopes.
The progress of this initiative must not be slackened. Soil erosion is arguably the worst global environmental problem, and for much of the world it was the least tractable until vetiver came along. All in all, this grass offers the first practical intervention with worldwide possibilities.
The Soil-Erosion Initiative's next major challenge is to project existing knowledge to new locations and new people. In a sense, it is essential to bring other nations up to the level of commitment and action achieved here in Thailand. If perhaps 100 more nations can be made as committed as this one, the global scourge of soil erosion would mostly be thwarted within our lifetimes. Of course, some nations are too frozen during winter to consider vetiver, but the United States is developing a complementary, vetiver-inspired, grass-hedge technology using cold-climate species.
Bringing about the tantalizing vision of global success against erosion should be the Soil-Erosion Initiative's aim. The existing vetiver publications are, by and large, adequate to the task. Farmers and foresters are of course the main audience, but it is necessary to reach out more to engineers and persuade them to take up vetiver routinely along roadsides, around construction sites, next to bridge abutments and along pipelines. Also it is essential to reach city officials so that vetiver is put to use stopping erosion in the squatter settlements, stormwater drains and other urban sites.
In addition, environmental scientists and conservation watchdog groups need to be made aware that vetiver is now a promising answer to the soil that washes into natural preserves. They could, for example, push for the regional employment of vetiver hedges to reduce the water-borne silt that devastates coral reefs, fish-spawning grounds and various other irreplaceable habitats. Three examples worth vigorous action are listed below.
The delicate balance of this irreplaceable habitat in Florida is being upset by phosphate and other nutrients washing out of nearby sugarcane fields. To me, the solution lies in surrounding the canefields with vetiver hedges. Those hedges would trap the silt (along with the phosphate clinging to it) and absorb soluble nutrients before the water ever passes into the Everglades.
This large lake in the heart of Africa is suffering explosive blooms of water hyacinth. I am informed that the problem has been linked to nutrient-laden silt washing off the land and fertilizing the weed. A regional vetiver-planting campaign in the watersheds serving the problem locations might immeasurably benefit the lake, not to mention the watersheds themselves.
The East African coast
The grass might also prove useful in watersheds in eastern Kenya, where silt washing off the land is killing a priceless coral reef.
The primary challenge in this initiative is not erosion control; it is to make extreme soils productive, or at least more productive than at present. This is also an important challenge. Vast areas of the earth typically classified as "marginal lands," "waste lands," or "abandoned lands" are inadequately used because they are just too hard to harness for crop production.
A truly amazing aspect of vetiver is its ability to survive on sites so hostile toward plant life that people now universally write them off as impossible to cultivate. The relevant feature in this case has to do with the plant's root chemistry. It is known from experiments and observations that vetiver grows in acid soil, alkaline soil, laterite, vertisol, toxic mine spoil, moderately saline soil, wetland and dryland soil, and even soils so dense they are likened, not inaccurately, to "concrete."
That vetiver can survive in such sites may at first sight seem just incidental, but having an adaptable and well-behaved plant that stays neatly in place is probably the missing key to mitigating the harshness of many now barren lands. Vetiver hedges in this case would be deployed as vegetative shock troops to seize a botanical bridgehead on hostile lands and open the way for other species to follow.
It seems likely that the lines of solid plant cover will indeed help get the restoration process started. Already the effect can be seen in many places. In Louisiana, for example, barren washes quickly fill with native vegetation after vetiver hedges stabilize the area. In northern India, sodic wastes were turned into luxuriant forests once vetiver hedges were in place. And in southern India, forests have been seen to colonize hillsides after vetiver hedges provided some protection.
This particular vetiver use is hardly well known and is deserving of its own dedicated initiative. Research, testing and a comparison of experiences are all needed in a wealth of difficult sites. Globally important extreme soils to include are vertisols, laterites, saline and sodic types. The "laterite" that dominates the lowland tropics is an especially potent challenge. That particular soil, red in colour, very acid and high in soluble aluminum, a deadly toxin to most plants, has long been considered beyond the possibility of high-yield farming, but the fact that vetiver survives (even thrives) in laterite could turn out to be one of the great breakthroughs for tropical agriculture and forestry.
Combinations of vetiver hedges with appropriate leguminous cover crops that renovate infertile land between the hedges need especial consideration. That one-two punch, based on a natural succession of the vetiver pioneer and the nitrogen-fixing successor, should open the doors to routine development of many now unusable sites. The combination with laterite-tolerant leguminous trees, such as Acacia mangium, could also be a powerful intervention.
Taken all round the Extreme-Soil Initiative is a way to "sell" vetiver to a new set of clients for whom soil erosion is not a main concern. Examples are land-use planners, international donors, economists, policymakers, government administrators and others worried over population pressures and immediate food supplies. In principle, hundreds of millions of hectares of now unused lands could be rejuvenated to support more people and more crops. Turning wastelands into farmlands would, in addition, be a way to save more natural forests from slash-and-burn destruction.
The fact that vetiver hedges are dense enough to dam up water is yet another distinctive feature. The effect is due to the plant's stems and myriad leaves, as well as to the soil and litter that collect behind a hedge. The effect is more sophisticated than people imagine; a vetiver hedge handles different depths of water in different ways. A modest, ground-level run-off hitting one of those hedges gets ponded, but a rushing torrent passes through with increasing ease as it rises past the point where the leaves splay outward. An established hedge seldom gets knocked down, and its variable-filter feature, damming up ground-level flows but progressively passing more water the deeper it gets, is an important one.
Professionals and policymakers involved in water issues are unaware that vetiver can help their efforts. This Water-Management Initiative needs to reach out and show them what they have to gain. Topics to highlight include the following.
By holding silt and water on hillslopes, vetiver hedges should be able to protect entire watersheds in the way that the original forests did. This would not only reduce soil loss and river sedimentation, but by keeping water on the land, vetiver would recharge groundwater supplies. Work in Malaysia shows that by using plants raised in pots, the hedges can become functioning barriers within weeks of being planted out. This holds the possibility of creating "instant" working watersheds over vast areas at modest cost. It would also mean that people might be able to stay living on the watersheds without severely affecting the area's vital hydrologic importance.
Vetiver planted along streams, river banks, canals, drains and ditches can help keep out silt, maintain the flow and prevent the banks from being undermined. This means, among other things, that capital investments in water supplies will be protected and enhanced.
This coarse grass with its roots like chicken mesh projecting several metres into the soil probably can strengthen earthen structures such as small dams and dikes. Following the disastrous Mississippi floods of 1993, it was reported that all levees protected by switchgrass remained unbroken. Vetiver should do at least as well because it is endowed with a better root and stem architecture for the task.
Waterside "walls" of vetiver hedge, grown on the banks of reservoirs, would provide ideal holding pens for dredge spoil. By allowing the water to filter back into the reservoir, these cheap, porous barriers would make it feasible to isolate the solids for economic handling by people or machines. Such self-rising silt-traps might help rescue reservoirs serving cities such as San Juan, Puerto Rico and Port-au-Prince, Haiti. Those reservoirs, along with many more in the tropics, are fast silting up and prematurely losing their capacity to hold water or generate electricity. Of course, vetiver hedges should also be put on the watersheds to stop the whole siltation process happening over again.
Vetiver hedges can be employed not only to retard run-off but to direct water toward, away from or through some given point. Hedges angled down slopes, for instance, would divert water away from sites such as unstable cliffs. For the cost of a few tillers and a planting effort, hydrologists and engineers could harness nature to achieve water shedding or water harvesting or other forms of water control.
Probably there is no better species for stripping nutrients out of domestic and, perhaps, industrial wastewater. A native of a wetland environment, vetiver withstands long immersion. Hedges grown across or around man-made marshes would probably block the passage of solids, strip out dissolved nutrients and detoxify pathogenic microbes through aeration or detention. By providing simple, compact water-treatment facilities that require no chemicals or pumps, vetiver could create a new and cheap form of tertiary wastewater treatment for the countries of the "Vetiver Zone." In return, these wastewater treatment facilities could become vetiver nurseries. Fertilized by the wastewater nutrients, the plants should throw off tillers in abundance. Employing human wastes to grow vetiver for planting where it can do good for people and the environment is a new and especially elegant notion of recycling.
In summary, this Water-Management Initiative could elevate vetiver into a tool for providing more reliable water supplies, reinforcing earthen dams, protecting riverbanks, treating domestic wastewater and much more. In selling the idea to hydrologists, sanitary engineers, public health specialists and so forth, a few spectacular successes could make all the difference. The Panama Canal, for example, would be a great showcase. Today, ship wakes erode parts of the canal banks, but vetiver hedges would absorb the swells and allow ship traffic to speed up, thereby increasing the canal's throughput and economy. Moreover, contour hedges on the surrounding hills and mountains would retard rainfall run-off, recharge groundwater supplies and probably restore the Chagres River to reliable year-round flow as in the days when those watersheds were fully clad in forest.
Although vetiver has many potential uses in pollution control, none is being vigorously developed or promoted. The initiative needed here is to reach out to governments, environmental scientists, industry and non-governmental organizations (NGO) concerned over cleaning up the messes that people or their institutions have left behind. Also, vetiver might be employed to prevent future messes from occurring or at least from spreading. Examples of what vetiver might help clean up are given below.
Surrounding polluted sites with vetiver hedges may well be a way to keep toxic compounds from moving outward underground. The massive, curtain-like "hangings" of interwoven roots seem ideally structured to filter out underground contaminants. If the plant can keep deadly pollutants corralled and unable to move outward and contaminate new ground, vetiver will have earned a place in everyone's gratitude.
Paul Truong's magnificent work in Australia has shown that vetiver is tolerant of high levels of arsenic, cadmium, chromium, copper and nickel. The plant therefore seems highly suitable for rehabilitating and maybe reclaiming lands contaminated by heavy metals, as well as perhaps by radionuclides and similar horrors resulting from mining, other industries, research facilities, landfills or illegal waste dumps.
No one has reported trying vetiver hedges against spills of industrial liquids, but it seems to me that a series of these very dense hedges would provide a cheap and probably effective backup protection against small spills at least. It would hardly matter if the hedges died, they could be easily replaced. Even crude oil might be held back. Indeed the oil-soaked vegetation could be burned for furnace fuel.
As mentioned above, vetiver hedges could block nutrient-laden run-off, which is a rising concern these days. Vetiver hedges could be especially useful as a "filtration barrier" around farms, industrial facilities, landfills and even golf courses. It could also be useful around ponds and marshes built to contain or detain run-off, notably stormwater from city streets.
Hydroponics might be a way to use vetiver hedges to filter dangerous materials out of surface waters. This is a speculative and untested idea but, as noted, the plant is at home in watery conditions. In one form of hydroponics the plants would be grown in an inert and highly pervious material through which the waters would pass. Coir dust, peatmoss, or perlite are possibilities. In another, vetiver might be grown with its massive roots dangling free in the water. This far-out idea, which works for other plants, requires something (old tyres perhaps) to keep the vetivers from sinking. Floating hedges might even be deployed across streams or canals to strip pollutants and dissolved nutrients out of the water flowing past. This water-borne process might even prove a convenient way of growing vetiver roots for oil extraction as no digging is needed, as the root ends are clipped when they grow too long).
The possibility of treating human wastes in man-made vetiver-filled wetlands has already been mentioned. This non-chemical wastewater treatment also seems promising for cleaning waste products from aquaculture. It is already removing nutrients from trout-farm effluent in trials at a U.S. Department of Agriculture research facility in West Virginia.
Taken all round, this Pollution-Control Initiative opens up vetiver applications relating to some of the best funded areas of research, with billions of dollars being spent on pollution controls in the United States alone. But the use of the grass is not currently a part of the experts' thinking. To correct that, vetiver needs to be tested widely in polluted sites, and fast. A success or two could launch our grass into new, big-time and well funded applications. In fact it would transform the world's appreciation of the plant overnight. In people's minds, a tool for removing deadly toxic hazards is something quite different from a tool for controlling soil erosion on foreign farms. Such a change of attitude would help everything.
Unless farmers deeply appreciate the plant and fully recognize that they are benefiting from it daily, we will always have to struggle to get vetiver hedges on the land. So, whilst emphasizing grand global problem-solving, such as mentioned above, it is necessary to get millions of farmers eagerly planting vetiver for themselves and selling the surplus. To assure this special efforts are needed to produce worldwide appreciation of the benefits to growers. Many farmers will not plant anything new just for erosion control, but they will eagerly tend a crop that provides income or makes their lives easier or more secure. Here are some features of vetiver that provide saleable products or a better life for farm families. Handicrafts: vetiver's bamboo-like stems are ideal for making baskets and other small saleable items. Thatch: the leaves make one of the longest lasting and most beautiful roofs. Supplementary Feed: although not a great feedstuff, vetiver is better than many give it credit. Improved Crop Yields: holding moisture back fosters better crop growth and helps keep wells filled. Wildlife Controls: pests such as rodents and Africa's grain-devouring quelea bird might be kept out of crops. The birds, for example, like to roost in blocks of tall grass, and there can be trapped in the darkness of night and used as food. Mulch: the leaves create a long-lived mulch that helps garden plants survive adversity. Windbreaks: standing up to 3 m tall, vetiver is ideally structured to resist the wind. Boundary Markers: several African nations recognize property lines demarked by vetiver because it stays in such a narrow band. It is a cheap way to stake out property rights. Air-conditioning: mats woven from vetiver roots are placed over window openings and doused with water to cool millions of India's houses. This both chills and perfumes the breezes passing through and the process may have much wider potential. Ornamentals: in Miami, vetiver plants are being taken up for their beauty and good behavior in the landscape. Screening: the tall, dense hedges are a way to provide a measure of privacy around houses, latrines, etc.
Moreover, circles of vetiver might be used to enclose compost piles, trash heaps, farm gardens, fish ponds and more. Animal Protection: corrals and shelters for small creatures such as chickens seem a possibility. Traffic Control: vetiver can be employed to direct where people and animals walk and where vehicles drive. For instance, it can keep them away from unstable banks or family gardens. Weed Prevention: the hedges are said to prevent creeping weeds, such as Bahia grass, from invading gardens. Making Steep Slopes Usable: hedges across slopes make it possible to work where now even standing is difficult and everything washes away with the rains.
All of these farmer advantages need to be developed and exploited throughout vetiver country. They should be brought together in extension literature. In this case, the publications might mention erosion-prevention, but their more immediate purpose is to stress benefits to the farmers' daily income and existence. In addition, commercial markets for vetiver tillers, handicrafts, thatch, "air-conditioning mats" and other products need to be advanced. Moreover, rather than establish centralized nurseries, a commerce in farmer-supplied planting materials should be encouraged.
Given the deep roots, high tops and thick hedges, as well as the promise of practical large-scale application, it seems obvious that this grass could play a role in mitigating and, perhaps, preventing various natural disasters.
This topic, speaking technically, overlaps water management and soil-erosion control, but speaking in the political and humanitarian sense, the topic of disaster prevention makes vetiver of interest to different ministries and industries. Here the ultimate goal is not just to control water and retain soil, but to save lives and reduce property damage. The Disaster-Prevention Initiative, then, is a way to reach out to the worldwide insurance business, mortgage lenders, governments and more. Below are some possibilities where vetiver might make the difference.
The stiff, strong tops of vetiver hedges stop mud and debris from passing by. The massive underground walls of interlocking roots seem likely to stop slopes from slumping. The plant should operate on an essentially permanent basis to protect unstable sites from causing damage to property and people's lives.
It has already been mentioned that vetiver hedges may be planted in ways that rob floodwaters of the power to cause destruction. This, and the fact that the hedges can hold rainfall on the watersheds, should help reduce the devastation of flooding.
In South Africa it has been found that burning off the hedges at the end of the wet season results in a flush of growth that stays succulent through the subsequent dry months. The local insurance industry has accepted this band of green vegetation as an effective firebreak.
By helping extend groundwater and surface water supplies in for instance, watersheds and reservoirs as mentioned above, vetiver should be able to benefit drought-prone areas.
Some (many?) earthen structures are in danger of collapse. A decade or two ago a dam in the hills above Los Angeles burst, releasing a deluge that caused immense property damage and some deaths. Vetiver appears to have the potential to be an inexpensive reinforcement for such structures. Levees around New Orleans and along the lower Mississippi are likely candidates. Were they to break, the devastation could be catastrophic.
One cannot be certain about vetiver's utility in any of these undertakings, but the authorities charged with disaster prevention should be given a chance to put vetiver to the test. Whatever is done to prevent disasters such as floods will have to be done over vast areas, but vetiver seems more suited to large-scale application than other possibilities, such as those employing concrete and steel.
This use of vetiver in emergency management would come clear to the appropriate authorities and businesses if it were employed on some high-profile sites. An example might be Mt. Pinatubo in the Philippines where the massive landslides of volcanic debris are inundating towns and villages and forcing the relocation of whole peoples. In addition, disastrous mudslides have in the last few years caused deaths and/or destruction in Puerto Rico, Haiti, Leyte in the Philippines and Malibu in Southern California. All those locations seem ideal for vigorous vetiver growth.
In addition, the Mekong watershed might be tackled as an international vetiver-planting testbed. The idea would be to keep silt out of the river and future floodwaters out of people's houses. If the critical upland slopes can be returned to the hydrological state they enjoyed when fully forested then perhaps Thailand's terrible floods can become only a thing of memory. A similar, but even bigger, challenge would be the protection of Bangladesh from Himalayan floodwaters. Such a mission might seem too vast to be possible, but vetiver would be a better intervention to start with than anything else currently understood.
For all our experience, the truth is that vetiver specialists still do not know much about how the plant functions. Yet the workings of vetiver underpin everything claimed or envisaged. What makes this grass work so well at so many things? What makes it different from other plants? These and many more questions need urgent answering. (For references on vetiver anatomy, biochemistry and physiology see Chapter 2.)
In this Basic-Science Initiative the audience comprises specialists such as plant physiologists, microbiologists and agrostologists (grass scientists). The topics here relate to pure science, rather than strictly to practical affairs. Areas for investigation include CO2 Absorption: in this era of the global warming scare, it is important to measure how much greenhouse gas vetiver stores in its massive roots.13C Absorption: is vetiver, like corn, an accumulator of this uncommon isotope? Taxonomy: what exactly is the relationship between the sterile domesticated plants and the seed-producing wild ones? Translocation of Oxygen: rice survives in flooded paddies because it moves oxygen down into its roots. Vetiver also survives in paddies. Can it do the same? Heavy Metals: how well do pollutants move upwards from the roots to the leaves? Is vetiver a "super-bioaccumulator"? Disease Prevention: the plant is remarkably healthy, but we need to understand the basis of its resistance to such things as fungi and viruses. We also need breeding and selection programs because even a small and solitary disease outbreak could threaten the whole world's vetiver plantings. Mechanism of Sterility: why is the plant sterile? How reliable is that sterility? Genetic Diversity: what are the different types of vetiver? Are some better adapted for the various purposes than others? Mycorrhiza: these fungi that colonize roots probably are one of the keys to the plant's survival in extreme sites. We need to know more about such symbiosis (see Chapters 2 and 7). Nitrogen Fixation: does vetiver survive on barren sites because, like a few other grasses, it has a symbiosis with nitrogen-fixing bacteria? Cold Sensitivity: this is perhaps the biggest limitation for temperate-zone countries such as the United States. Can it be reduced or overcome? General Tolerances: what are the theoretical limits to drought, waterlogging, and toxic conditions? What can be expected in practice? Mechanism of Hedge Formation: why do the plants in a hedge tend to interlock when most grasses stay in separate clumps? Dwarfing: can shorter plants be obtained? Root Growth: just how strong are those reinforcings in the soil?
With topics such as these it is necessary to reach out to scientists in the appropriate fields and show them how by applying their expertise to vetiver they can produce data of global importance. This is one area where vetiver specialists have the possibility of finding research partners likely to devote time and energy without much cajoling. This is because in the grass family vetiver falls between sugarcane, sorghum and corn, which means that it probably has much to contribute to the better understanding of those billion-dollar natural resources. Researchers studying the basics of sugarcane, sorghum and corn, are therefore natural allies of vetiver specialists.
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