VETIVER GRASS

A thin green line against erosion

Board on Science and Technology for International Development

National Research Council

National Academy Press
Washington, D.C.
1993



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Vetiver Grass: A Thin Green Line Against Erosion VETIVER GRASS A thin green line against erosion Board on Science and Technology for International Development National Research Council National Academy Press Washington, D.C. 1993

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Vetiver Grass: A Thin Green Line Against Erosion NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competence and with regard for appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Stuart Bondurant is acting president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council. The Board on Science and Technology for International Development (BOSTID) of the Office of International Affairs addresses a range of issues arising from the ways in which science and technology in developing countries can stimulate and complement the complex processes of social and economic development. It oversees a broad program of bilateral workshops with scientific organizations in developing countries and conducts special studies. BOSTID's Advisory Committee on Technology Innovation publishes topical reviews of technical processes and biological resources of potential importance to developing countries. This report has been prepared by an ad hoc advisory panel of the Board on Science and Technology for International Development, Office of International Affairs, National Research Council. Support for this project was provided by the Division of Environment of the International Bank for Reconstruction and Development (The World Bank), the Soil Conservation Service of the U.S. Department of Agriculture, and the Office of the Science Advisor of the Agency for International Development Grant No. DPE-5545-A-OO-8068-00. Library of Congress Catalog Card Number: 92-050175 ISBN 0-309-04269-0

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Vetiver Grass: A Thin Green Line Against Erosion PANEL ON VETIVER NORMAN E. BORLAUG, Centro Internacional de Mejoramiento de Maíz y Trigo Mexico City, Mexico, Chairman RATTAN LAL, The Ohio State University, Columbus, Ohio, USA DAVID PIMENTEL, Cornell University, Ithaca, New York, USA HUGH POPENOE, University of Florida, Gainesville, Florida, USA NOEL D. VIETMEYER, Vetiver Study Director and Scientific Editor MARK R. DAFFORN, Staff Associate STAFF F.R. RUSKIN, BOSTID Editor ELIZABETH MOUZON, Senior Secretary BRENT SIMPSON, MUCIA Intern MICHAEL MCD. DOW, Acting Director, BOSTID CONTRIBUTORS I. P. ABROL, Department of Soils, Agronomy, and Agroforestry, Indian Council of Agricultural Research, Krishi Bhawan, New Delhi, India EDITHE ALEXANDER, Stanthur and Company, Ltd., Castries, St. Lucia CHARLES H. ANTHOLT, Agriculture Division, Asia Technical Department, The World Bank, Washington, D.C., USA ERIK ARRHENIUS, The World Bank, Washington, D.C., USA JACQUES BARRAU, Laboratoire d'Ethnobotanique-Biogéographie, Muséum National d'Histoire Naturelle, Paris, France CLIFFORD BELLANDE, CARE-Haiti, Port-au-Prince, Haiti MICHAEL BENGE, Agency for International Development, Washington, D.C., USA PAT BOYD, U.S. Department of Agriculture, Glenn Dale, Maryland, USA TOM BREDERO, The World Bank, Antananarivo, Madagascar ROBERT CHAMBERS, Institute of Development Studies, University of Sussex, Brighton, UK GEOFFREY P. CHAPMAN, Wye College, University of London, Wye, Near Ashford, Kent, UK

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Vetiver Grass: A Thin Green Line Against Erosion GABRIEL CHARLES, Ministry of Agriculture, Castries, St. Lucia CAROL COX, Ecology Action, Willits, California, USA SELWYN DARDIANE, Director of Forests, Trinidad and Tobago KITTIE DERSTINE, Soil Conservation Service, U.S. Department of Agriculture, Baton Rouge, Louisiana, USA MEL DUVALL, George Mason University, Fairfax, Virginia, USA H. A. ELWELL, Institute of Agricultural Engineering, Borrowdale, Harare, Zimbabwe V. GIBBERD, E. M. I. Soil and Water Conservation Project, Ministry of Agriculture, Embu, Kenya M. GRASSI, Instituto de Botánica, Fundación Instituto Miguel Lillo, San Miguel de Tucumán, Argentina JOHN C. GREENFIELD (The World Bank, retired), Kerikeri, New Zealand RICHARD G. GRIMSHAW, Agriculture Division, Asia Technical Department, The World Bank, Washington, D.C., USA BRUCE HANSEN, Herbarium, University of South Florida, Tampa, Florida, USA R. M. JARROLD, MASDAR (UK) Ltd., Finchampstead, Berkshire, UK EMANUEL L. JOHNSON, U.S. Department of Agriculture, Beltsville, Maryland, USA MAURICE JONES, Vetiver Grass Stabilization cc, Management Agricultural Services, Howick, South Africa R. S. JUNOR, Soil Conservation Service, New South Wales, Chatswood, New South Wales, Australia W. DORAL KEMPER, Agricultural Research Service, U.S. Department of Agriculture, Beltsville Agricultural Research Center, Beltsville, Maryland, USA T. N. KHOSHOO, Tata Energy Research Institute, New Delhi, India MATHIEU KUIPERS, CORDECO-MACA, Cochabamba, Bolivia GERALD R. LEATHER, U.S. Department of Agriculture, Frederick, Maryland, USA GILBERT LOVELL, Southern Regional Plant Introduction Station, U.S. Department of Agriculture, Griffin, Georgia, USA WILLIAM S. LUCE, Miami Beach, Florida, USA WILLIAM B. MAGRATH, Environmental Policy Research Division, The World Bank, Washington, D.C., USA MICHAEL MCGAHUEY, Agency for International Development, Washington, D.C., USA MIKE MATERNE, Soil Conservation Service, U.S. Department of Agriculture, Baton Rouge, Louisiana, USA RAMIRO MATOS MENDIETA, Colegio Real, Universidad Nacional Mayor de San Marcos, Lima, Peru

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Vetiver Grass: A Thin Green Line Against Erosion D. E. K. MILLER, New Zealand Department of Scientific and Industrial Research, Palmerston North, New Zealand STANDLEY MULLINGS, Stanthur and Company, Ltd., Castries, St. Lucia ALAN NORDMEYER, Forest and Range Experiment Station, Forest Research Institute, Ministry of Forestry, Christchurch, New Zealand CALEB O. OTHIENO, Tea Research Foundation of Kenya, Kericho, Kenya KENNETH PIDDINGTON, Office of Environment, The World Bank, Washington, D.C., USA C. SITAPATHI RAO, Agriculture and Rural Development Area, Administrative Staff, College of India, Bella Vista, Hyderabad, India JOHN (MARC) SAFLEY, JR., Soil Conservation Service, U.S. Department of Agriculture, Washington, D.C., USA CINDY SCHEXNAYDER, Soil Conservation Service, U.S. Department of Agriculture, Baton Rouge, Louisiana, USA W. CURTIS SHARP, National Plant Materials Laboratory, Soil Conservation Service, U.S. Department of Agriculture, Washington, D.C., USA HOLLY SHIMIZU, U.S. Botanic Gardens, Washington, D.C., USA JAMES SMYLE, Agriculture Division, Asia Technical Department, The World Bank, Washington, D.C., USA S. SUBRAMANIAN, Soil and Water Management Research Institute, Naidu Agricultural University, Thanjavur, India ANTHONY TANTUM, Vetiver Grass Stabilization cc, Management Agricultural Services, Howick, South Africa PAUL P. S. TENG, International Rice Research Institute, Los Bãnos, Philippines PAT THURBON, Department of Primary Industries, Brisbane, Queensland, Australia PAUL TRUONG, Soil Conservation Research, Department of Primary Industries, Indooroopilly, Brisbane, Queensland, Australia ARNOLD TSCHANZ, U.S. Department of Agriculture, Hyattsville, Maryland, USA LY TUNG, Farm and Resource Management Institute, Visayas State College of Agriculture, Pasay City, Philippines GORO UEHARA, University of Hawaii, Honolulu, Hawaii, USA J. J. P. VAN WYK, Research Institute for Reclamation Ecology, Potchefstroom University for Christian Higher Education, Potchefstroom, South Africa RAY WEIL, University of Maryland, College Park, Maryland, USA PETER WELLE, CARE Haiti, Port-au-Prince, Haiti P. K. YOON, Plant Science Division, Rubber Research Institute of Malaysia, Experiment Station, Kuala Lumpur, Selangor, Malaysia

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Vetiver Grass: A Thin Green Line Against Erosion Preface For developing nations, soil erosion is among the most chronic environmental and economic burdens. Many of these nations are in the tropics, where in just a few hours torrential downpours can wash away tons of topsoil from each hectare. Many others are in the drier zones, where swirling winds and flash floods (sometimes from rains so distant they are unseen) can be equally devastating. By these processes, huge amounts of valuable soil are being lost every day. Worse, the soil accumulates in rivers, reservoirs, harbors, estuaries, and other waterways where it is unwelcome, terribly destructive, and impossibly costly to remove. Erosion is thus a double disaster: a vital resource disappears from where it is desperately needed only to be dumped where it is equally unwanted. Despite much rhetoric and effort, little has been accomplished in overcoming erosion, at least when viewed from a worldwide perspective. One major reason is that there are few if any solutions that are cheap, appealing, long lived, and suitable for easy adoption over the vast expanses of the Third World that need protecting. Now, however, there may be one. In the eyes of at least some viewers, a little-known tropical grass, vetiver, might at last offer one practical and inexpensive solution for controlling erosion simply, cheaply, and on a huge scale in both the tropical and semiarid regions. Planted in lines along the contours of sloping lands, vetiver quickly forms narrow but very dense hedges. Its stiff foliage then blocks the passage of soil and debris. It also slows any runoff and gives the rainfall a better chance of soaking into the soil instead of rushing off the slope. Although there has not been much experience with this process to date, the deeply rooted, persistent grass has restrained erodible soils in this way for decades in Fiji, India, and some Caribbean nations. At least in this limited practice, vetiver appears truly remarkable. The grass itself seems not to spread or become a pest. Terraces rise as the soil accumulates behind the hedges, converting erodible slopes into stabilized terraces where farming and forestry can be conducted, safe from the evils of erosion. Farmers and foresters benefit not only

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Vetiver Grass: A Thin Green Line Against Erosion by keeping their soil, but by having flatter land and more moisture for their plants. Countries benefit by having cleaner rivers, unspoiled estuaries, and more water and less silt in their reservoirs. At present, however, no one knows for sure whether these experiences represent a practical possibility for solving the world's worst erosion problems. The purpose of this report is to make a judgment on this point: to assess vetiver's promise and limitations and to identify any research that may be necessary before this grass can be deployed rationally, widely, and without undue environmental risk. In other words, our particular purpose is to evaluate the ecological advantages and potential risks in employing a grass that may eventually benefit watersheds, forests, and farms throughout the world's warmer zones. This book, it should be understood, is neither a monograph on vetiver nor a field guide for its use. It is, instead, a scientific audit of the safety and effectiveness of the plant as used for erosion control. Basically, the book reviews existing research and experiences with the grass. It has been compiled from literature, from personal contacts, from site visits, and from information mailed in by specialists in an array of disciplines: environment, agronomy, forestry, soil science, engineering, and others. Many contributors had little or no knowledge of vetiver itself; they served as "devil's advocates." We hope that this exhaustive process has produced an independent, unbiased evaluation that will help scores of countries and organizations judge whether or not to use this plant in their own programs. The report has been produced particularly for nonspecialist readers such as government ministers, research directors, university students, private voluntary organizations, and entrepreneurs. It is intended primarily as an economic development document. We hope it will be of particular interest to agencies engaged in development assistance and food relief; officials and institutions concerned with environment, agriculture, and forestry in tropical countries; and scientific establishments with relevant interests. This study is a project of the Board on Science and Technology for International Development (BOSTID), a division of the National Research Council, and is prepared under the auspices of BOSTID's program on technology innovation. Established in 1970, this program evaluates unconventional scientific and technological advances with particular promise for solving problems of developing countries (see page 158). The report continues a series describing promising plant resources that heretofore have been neglected or overlooked. Other titles relating to vegetative improvements for tropical soils and environment include: Tropical Legumes: Resources for the Future (1979)

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Vetiver Grass: A Thin Green Line Against Erosion Leucaena: Promising Forage and Tree Crop in Developing Countries (second edition, 1984) Mangium and Other Fast-Growing Acacias for the Humid Tropics (1983) Calliandra: A Versatile Small Tree for the Humid Tropics (1983) Casuarinas: Nitrogen-Fixing Trees for Adverse Sites (1983) Firewood Crops: Shrub and Tree Species for Energy Production, Volumes I and II (1980 and 1983, respectively) Sowing Forests from the Air (1981) Neem: A Tree for Solving Global Problems (1992). Funds for carrying out this vetiver study were made available by the following organizations: The Office of the Science Advisor of the U.S. Agency for International Development; The Environment and the Agriculture and Rural Development departments of the World Bank; and The Soil Conservation Service of the U.S. Department of Agriculture. Additional funds for printing the report were contributed by the International Tropical Timber Organization as well as by the following departments of the World Bank: Agriculture and Rural Development, Environment, External Affairs, and Asia Technical. The following World Bank country divisions also contributed: South Asia, East Asia, Latin America, and Africa. How to cite this report: National Research Council. 1993. Vetiver Grass: A Thin Green Line Against Erosion. National Academy Press, Washington, D.C.

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Vetiver Grass: A Thin Green Line Against Erosion Contents     Foreword   xiii     Introduction   1     Background And Conclusions     1   Worldwide Experiences   11 2   Case Studies   32 3   Conclusions   49     Technical Issues     4   Questions and Answers   59 5   The Plant   71 6   Next Steps   84     Appendixes     A   Great Challenges, Great Opportunities   94 B   Other Potential "Vetivers"   113 C   Selected Readings   128 D   Research Contacts   130 E   Biographical Sketches   156     The BOSTID Innovation Program   158     Board on Science and Technology for International Development (BOSTID)   161     BOSTID Publications in Print   162

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Vetiver Grass: A Thin Green Line Against Erosion Foreword Soil erosion is a quiet crisis, an insidious, largely man-made disaster that is unfolding gradually. In many places it is barely recognized; the soil moves away in such small increments from day to day that its loss is hardly noticed. Often the very practices that cause the greatest losses in the long term lead to bumper crops in the short term, thereby creating an illusion of progress. Yet erosion is inexorably undermining the economic security of most countries. The changes it brings are chronic and irreversible: lost land; reduced productivity on farms and in forests; floods; silted harbors, reservoirs, canals, and irrigation works; washed-out roads and bridges; and destroyed wetlands and coral reefs, where myriad valuable organisms would normally breed and prosper. And erosion is literally costing the earth. The soil it carries off now totals 20 billion tons a year worldwide. That represents the equivalent loss of between 5 million and 7 million hectares of arable land. Some of this loss is alleviated by converting forests into farms, so that erosion indirectly also leads to deforestation. The problems are worst in the warmer parts of the world. There, swelling populations, poor land management, vulnerable soils, and hostile climates add up to a lethal combination that fosters erosion, bringing with it environmental degradation, falling crop yields, rising deforestation, erratic water supplies, and an ever-expanding prospect of dry and dusty rangelands too lacking in soil for crops or even livestock. Soil erosion is getting worse. In sub-Saharan Africa, for example, it has increased 20-fold in the last three decades as more and more people are forced to move out of the good bottomlands and onto the fragile hillsides. More than one-third of Africa, for example, is threatened with desertification. The world's forests are disappearing 30 times faster than they are being planted. Hillsides stripped of their protective covering of vegetation are rapidly eroding, depositing huge amounts of silt into downstream reservoirs and river valleys. Floods are becoming more frequent—and more severe.

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Vetiver Grass: A Thin Green Line Against Erosion A few facts demonstrate the crisis: Morocco has to install the equivalent of a new, 150-million cubic meter reservoir every year just to keep pace with the sediment that is filling up its existing dams. Zimbabwe, it is estimated, would have to spread US$1.5 billion worth of fertilizers merely to compensate for the natural nutrients now being swept away by wind and rain every year. China loses more than 2 billion tons of soil a year, just from the Loess Plateau. Most is deposited in the Yellow River. And it takes 3.5 billion cubic meters of water to flush every 100 million tons of soil to the sea—water that could be used for productive purposes. U.S. farmers must add 20 kilograms of nitrogen fertilizer for every centimeter of soil lost per hectare, just to maintain productivity. Indeed, each year the United States loses $18 billion in fertilizer nutrients to soil erosion. To avert the global environmental disaster being brought on by soil erosion, it is imperative to take action quickly and on a vast scale. Unfortunately, previous efforts to tackle the problem worldwide—especially in the Third World—were rarely successful over any extensive area. For one thing, some of the conventional techniques employed today are enormously expensive. For another, they rarely generate widespread farmer support—indeed, the farmers often object so vehemently that they have to be threatened with fines or prison to assure compliance. And, wherever the farmers are unmotivated, even the most effective systems soon decline and fall into decay and disuse. It was with this grim scenario in mind that the staff of the NRC became intrigued by the ideas of two World Bank agriculturists, John Greenfield and Richard Grimshaw. These two had an entrancing vision: a little-known tropical grass called vetiver, they proposed, could provide the answer to soil erosion in the world's warmer regions—and it could do so in a way that would appeal to millions of farmers, landowners, politicians, and administrators. In their eyes, local people would at last be motivated to protect their land and therefore create the solution rather than the problem. Greenfield and Grimshaw's concept, as well as the reasons behind it, are described in the next chapter. Subsequent chapters highlight the findings of the NRC panel, whose task was to assess the underlying truth of the vetiver idea and to project its promise into the future. NOEL D. VIETMEYER STUDY DIRECTOR