Sustainable Agriculture and the Environment in the HUMID TROPICS

Committee on Sustainable Agriculture and the Environment in the Humid Tropics

Board on Agriculture

and

Board on Science and Technology for International Development

National Research Council

NATIONAL ACADEMY PRESS
Washington, D.C.
1993



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Sustainable Agriculture and the Environment in the HUMID TROPICS Sustainable Agriculture and the Environment in the HUMID TROPICS Committee on Sustainable Agriculture and the Environment in the Humid Tropics Board on Agriculture and Board on Science and Technology for International Development National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1993

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Sustainable Agriculture and the Environment in the HUMID TROPICS NATIONAL ACADEMY PRESS 2101 Constitution Avenue Washington, DC 20418 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 competences 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. This report has been prepared with funds provided by the Office of Agriculture, Bureau for Research and Development, U.S. Agency for International Development, under Amendment No. 2 of Cooperative Agreement No. DPE-5545-A-00-8068-02. Partial funding was also provided by the Office of Policy Analysis of the U.S. Environmental Protection Agency through this cooperative agreement. The U.S. Agency for International Development reserves a royalty-free and nonexclusive and irrevocable right to reproduce, publish, or otherwise use and to authorize to use the work for government purposes. Cover illustration by Michael David Brown © 1987. Library of Congress Cataloging-in-Publication Data National Research Council (U.S.). Committee on Sustainable Agriculture and the Environment in the Humid Tropics. Sustainable agriculture and the environment in the humid tropics / Committee on Sustainable Agriculture and the Environment in the Humid Tropics, Board on Agriculture and Board on Science and Technology for International Development, National Research Council. p. cm. Includes bibliographical references and index. ISBN 0-309-04749-8 1. Agricultural systems—Tropics. 2. Sustainable agriculture—Tropics. 3. Land use, Rural—Tropics. 4. Agricultural ecology—Tropics. I. Title. S481.N38 1992 92-36869 333.76′15′0913—dc20 CIP © 1993 by the National Academy of Sciences. All rights reserved. No part of this book may be reproduced by any mechanical, photographic, or electronic process, or in the form of a phonographic recording, nor may it be stored in a retrieval system, transmitted, or otherwise copied for public or private use without written permission from the publisher, except for the purposes of official use by the U.S. government. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for this project. Printed in the United States of America

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Sustainable Agriculture and the Environment in the HUMID TROPICS COMMITTEE ON SUSTAINABLE AGRICULTURE AND THE ENVIRONMENT IN THE HUMID TROPICS RICHARD R. HARWOOD, Chair, Michigan State University MARY E. CARTER, U.S. Department of Agriculture RODRIGO GÁMEZ, Instituto Nacional de Biodiversidad, Costa Rica STEPHEN R. GLIESSMAN, University of California, Santa Cruz ARTURO GÓMEZ-POMPA, University of California, Riverside LOWELL S. HARDIN, Purdue University WALTER A. HILL, Tuskegee University RATTAN LAL, Ohio State University GILBERT LEVINE, Cornell University ARIEL E. LUGO, U.S. Department of Agriculture, Forest Service, Puerto Rico ALISON G. POWER, Cornell University VERNON W. RUTTAN, University of Minnesota PEDRO A. SANCHEZ, International Center for Research in Agroforestry, Kenya E. ADILSON SERRÃO, Center for Agroforestry Research of the Eastern Amazon, Brazil PATRICIA C. WRIGHT, State University of New York, Stony Brook Staff MICHAEL MCD. DOW, Study Director CARLA CARLSON, Senior Staff Officer CURT MEINE, Staff Associate BARBARA J. RICE, Staff Associate and Editor JANET L. OVERTON, Associate Editor DAVID HAMBRIC, Senior Project Assistant ALWIN PHILIPPA, Senior Program Assistant

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Sustainable Agriculture and the Environment in the HUMID TROPICS BOARD ON AGRICULTURE THEODORE L. HULLAR, Chair, University of California, Davis PHILIP H. ABELSON, American Association for the Advancement of Science DALE E. BAUMAN, Cornell University R. JAMES COOK, Agricultural Research Service at Washington State University ELLIS B. COWLING, North Carolina State University PAUL W. JOHNSON, Natural Resources Consultant, Decorah, Iowa NEAL A. JORGENSEN, University of Wisconsin ALLEN V. KNEESE, Resources for the Future, Inc. JOHN W. MELLOR, John Mellor Associates, Inc. DONALD R. NIELSEN, University of California, Davis ROBERT L. THOMPSON, Purdue University ANNE M. K. VIDAVER, University of Nebraska JOHN R. WELSER, The Upjohn Company Staff SUSAN OFFUTT, Executive Director JAMES E. TAVARES, Associate Executive Director CARLA CARLSON, Director of Communications BARBARA J. RICE, Editor

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Sustainable Agriculture and the Environment in the HUMID TROPICS BOARD ON SCIENCE AND TECHNOLOGY FOR INTERNATIONAL DEVELOPMENT ALEXANDER SHAKOW, Chair, The World Bank PATRICIA BARNES-MCCONNELL, Michigan State University JORDAN J. BARUCH, Jordan Baruch Associates BARRY BLOOM, Albert Einstein College of Medicine JANE BORTNICK, Library of Congress GEORGE T. CURLIN, National Institutes of Health DIRK FRANKENBERG, University of North Carolina, Chapel Hill RALPH W. F. HARDY, Boyce-Thompson Institute for Plant Research, Inc. FREDRICK HORNE, Oregon State University ELLEN MESSER, Brown University CHARLES C. MUSCOPLAT, MCI Pharma, Inc. JAMES QUINN, Dartmouth College VERNON W. RUTTAN, University of Minnesota ANTHONY SAN PIETRO, Indiana University ERNEST SMERDON, University of Arizona Ex Officio Members GERALD P. DINEEN, Foreign Secretary, National Academy of Engineering JAMES B. WYNGAARDEN, Foreign Secretary, National Academy of Sciences Staff MICHAEL MCD. DOW, Acting Director E. WILLIAM COLGLAZIER, Executive Director, Office of International Affairs

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Sustainable Agriculture and the Environment in the HUMID TROPICS 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. Kenneth I. Shine is 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.

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Sustainable Agriculture and the Environment in the HUMID TROPICS Preface The increasingly adverse effects of human activities on the earth 's land, water, atmospheric, and biotic resources have clearly demonstrated that a new attitude of stewardship and sustainable management is required if our global resources are to be conserved and remain productive. Nowhere is this need more urgent than in the world's humid tropics. Its populations, many subsisting at or below the poverty level, will continue to rely on the resource base to meet their needs. That base must be stabilized while becoming increasingly productive. Thoughtful and prompt actions, especially positive policy changes, are required to break the current pattern of unplanned deforestation in the humid tropics, to reverse environmental degradation caused by improper or mismanaged crop and animal production systems, and to revitalize abandoned lands. At the request of the U.S. Agency for International Development (USAID), the National Research Council's Board on Agriculture and the Board on Science and Technology for International Development convened the 15-member Committee on Sustainable Agriculture and the Environment in the Humid Tropics. The U.S. Environmental Protection Agency also provided support, emphasizing its interest in the global environmental implications of the problem. The study responds to the recognized need for sustainable land use systems that (1) maintain the long-term biological and ecological integrity of natural resources, (2) provide economic returns at the farm level, (3) contribute to quality of life of rural populations, and

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Sustainable Agriculture and the Environment in the HUMID TROPICS (4) integrate into national economic development strategies. In particular, the committee was asked to identify and analyze key problems of agricultural practices that contribute to environmental degradation and result in declining agricultural production in humid tropic environments. The committee began its work in March 1990. It sought to understand the overarching environmental, social, and policy contexts of land conversion and deforestation—and the promise of sustainable land uses—by integrating the views of experts in the broad areas of agriculture, ecology, and social sciences. Its work focused on the range of land use systems appropriate to the forest boundary, an area where agriculture and forestry merge in a continuum of production types involving trees, agricultural crops, and animals. The committee addressed intensive, high-input agriculture only as it relates to common environmental problems. The committee undertook supplemental analyses of tropical forest land use policies and the effects of tropical land use on global climate change. We sought a wide range of scientific data, specialized information, and expert views to address our broad charge. A critical component of the humid tropics equation that was not within the scope of the study is human population. The committee acknowledges population dynamics as a major factor in achieving sustainable land use and development in the humid tropics; the land use systems it describes fit a broad range of population densities. We stress the importance of population issues, particularly in this region of the world, but an analysis of population densities, pressures, and trends was not part of our study, nor does the composition of the committee reflect the demographic expertise necessary to address population issues. This report, Sustainable Agriculture and the Environment in the Humid Tropics, will contribute to the elusive “solution” to tropical deforestation through its outline of a variety of approaches to tropical land use and conservation. Each land use option would take advantage of the opportunities inherent in physical resource patterns, labor, market availability, and social setting, and each would contribute to the common goal of sustainability in the humid tropics. The land use options scheme in Chapter 2 and its accompanying table for evaluating land use attributes can be used as a guide in decision making. The presentation makes the information usable by in-country decision makers, from the local level on up, as well as by governmental and nongovernmental agencies. We believe the information in this report will be helpful to researchers, planners, and policymakers in industrialized countries and in developing countries.

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Sustainable Agriculture and the Environment in the HUMID TROPICS Part One is the committee's deliberative report. It emphasizes the restoration of degraded land, the importance of general economic growth as an alternative to forest exploitation, and the need for comprehensive management of forest and agricultural resources. The underlying premise of the committee's work is that under conditions of economic and social pressure, what is not managed today is at risk of being lost tomorrow. Within Part One, the Executive Summary discusses the findings of the committee and presents key recommendations. Chapter 1 describes the humid tropics, the consequences of forest conversion and deforestation, environmental factors affecting agriculture, and the fostering of sustainable land use in the humid tropics. Chapter 2 discusses major land use options that local, regional, and national managers might choose in making decisions to achieve food production goals, maintain or increase local income levels, and protect the natural resource base. Chapter 3 discusses technical research needs and presents recommendations on land use options. Chapter 4 presents policy imperatives to promote sustainability. The Appendix to Part One presents a discussion of emissions of greenhouse gases associated with land use change. To enhance its understanding, the committee commissioned a series of country profiles to gather information on land use and forest conversion in different countries, to evaluate general causes and consequences within specific contexts, to identify sustainable land use alternatives, and to compare policy implications. Seven country profiles are presented in Part Two. Authors review agricultural practices and environmental issues in Brazil, Côte d'Ivoire, Indonesia, Malaysia, Mexico, the Philippines, and Zaire. The committee's intent in this report is to make a positive statement about the potential benefits of sustainable agriculture in the humid tropics, rather than to condemn the forces that have contributed to the current situation. It is an attempt to promote the restoration and rehabilitation of already deforested lands, to increase their productivity, and to explore the policy changes required to take the next steps toward sustainability. Guidelines for future research and policy, whether for conserving natural ecosystems or for encouraging sustainable agroecosystems, must be designed with a global perspective and within the context of each country's environment, history, and culture. The committee underscores the fact that sustainable agriculture in any given country will consist of many diverse production systems, each fitting specific environmental, social, and market niches. Some alternatives require higher inputs, labor, or capital—depending

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Sustainable Agriculture and the Environment in the HUMID TROPICS on their makeup, resource base, and environment—but each must become more sustainable. Conversely, each system can contribute toward the sustainability of the agricultural system in general by helping to meet the varied and changing needs facing countries in the humid tropics. To maintain a diversity of approaches while making real progress toward common goals is the challenge that confronts all who are concerned with the future of the lands and people of the humid tropics. RICHARD R. HARWOOD, Chair Committee on Sustainable Agriculture and the Environment in the Humid Tropics

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Sustainable Agriculture and the Environment in the HUMID TROPICS Acknowledgments The disciplines, multidisciplinary experiences, expertise, and countries of the world that are represented by the many individuals who have generously contributed to this report constitute a very long list. Because of the efforts of the many who shared ideas and offered background knowledge, the committee was able to expand its views of issues relating to sustainable agriculture and the environment in the humid tropics and benefit from a variety of perspectives. Among the many individuals whose work was of special significance to this report are the authors of the appended paper, the country profiles, and their collaborators. The descriptive data and analyses presented in the seven country profiles, contained in Part Two of the report, provided much of the foundation for the committee 's work. In addition to the authors and their collaborators, the committee acknowledges the contributions of Cyril B. Brown, Purdue University; Avtar Kaul, Winrock International; Daniel Nepstad, Woods Hole Research Center; and Christopher Uhl, Pennsylvania State University. (Both Nepstad and Uhl are associated with the Center for Agroforestry Research of the Eastern Amazon, Belém, Brazil.) Michael Hayes provided valuable editorial assistance in preparing the country profiles for publication. To broaden its information resources, the committee convened two regional meetings on agricultural and environmental practices and policies in the humid tropics. The first meeting was held at the

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Sustainable Agriculture and the Environment in the HUMID TROPICS Faculty of Agronomy, University of Costa Rica, in San Jose. The second was held in Bangkok, Thailand, under the auspices of the Asian Regional Office of the National Research Council. During the course of its deliberations, the committee sought the counsel and advice of independent scholars and individuals representing a range of organizations. Among those who gave generously of their experience were Robert O. Blake, Committee on Agricultural Sustainability for Developing Countries; Erick Fernandes, Thurman Grove, and Cheryl Palm, North Carolina State University; Douglas Lathwell, Cornell University; Charles H. Murray, Food and Agriculture Organization of the United Nations; Stephen L. Rawlins, U.S. Department of Agriculture; R. D. H. Rowe, World Bank; Roger A. Sedjo, Resources for the Future; and John S. Spears, Consultative Group on International Agricultural Research. The assistance of Andrea Kaus and Veronique M. Rorive, University of California at Riverside, was also helpful to the committee. Research assistance was provided by three student interns, who were sponsored by the Midwest Universities Consortium for International Activities, Inc. The committee extends special thanks to Joi Brooks, University of Illinois at Urbana, and Jil Reifschneider and Kristine Agard, University of Wisconsin. The committee is grateful to Curt Meine and Barbara Rice, whose skill and teamwork transformed imperfect and incomplete draft materials into a comprehensive report. We are particularly grateful to Jay Davenport, whose insights and support were invaluable to the committee throughout the course of the study. And the committee especially recognizes the efforts of Pedro Sanchez, who served as committee chairman until assuming responsibilities as director general of the International Center for Research in Agroforestry, Nairobi, Kenya.

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Sustainable Agriculture and the Environment in the HUMID TROPICS Contents     EXECUTIVE SUMMARY   1      Findings,   2      Landscape Management: A Global Requirement,   4      The Humid Tropics,   5      Sustainable Land Use Options,   8      Recommendations,   12      Conclusion,   17  PART ONE         1 AGRICULTURE AND THE ENVIRONMENT IN THE HUMID TROPICS   21      The Humid Tropics,   22      Forest Characteristics and Benefits,   29      Conversion of Humid Tropic Forests,   33      Sustainable Agriculture in the Humid Tropics,   51      The Need for an Integrated Approach,   62      Moving Toward Sustainability,   64     2 SUSTAINABLE LAND USE OPTIONS   66      Intensive Cropping Systems,   70      Shifting Cultivation,   77      Agropastoral Systems,   82      Cattle Ranching,   85

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Sustainable Agriculture and the Environment in the HUMID TROPICS      Agroforestry Systems,   92      Mixed Tree Systems,   100      Perennial Tree Crop Plantations,   110      Plantation Forestry,   115      Regenerating and Secondary Forests,   118      Natural Forest Management,   125      Modified Forests,   132      Forest Reserves,   133     3 TECHNOLOGICAL IMPERATIVES FOR CHANGE   138      Knowledge About Land Use Options,   139      Land Use Design and Management Considerations,   145      Ecologic Guidelines for Systems Management,   154      Technical Needs Common to All Land Use Options,   155      Commodity-Specific Research Needs,   158     4 POLICY-RELATED IMPERATIVES FOR CHANGE   159      Managing Forests and Land Resources,   161      Supporting Sustainable Agriculture,   173      Other Policy Areas Affecting Land Use,   188      REFERENCES   192      APPENDIX: EMISSIONS OF GREENHOUSE GASES FROM TROPICAL DEFORESTATION AND SUBSEQUENT USES OF THE LAND Virginia H. Dale, Richard A. Houghton, Alan Grainger, Ariel E. Lugo, and Sandra Brown   215  PART TWO:   COUNTRY PROFILES        BRAZIL Emanuel Adilson Souza Serrão and Alfredo Kingo Oyama Homma   265      CÔTE D'IVOIRE Simeon K. Ehui   352      INDONESIA Junus Kartasubrata   393      MALAYSIA Jeffrey R. Vincent and Yusuf Hadi   440      MEXICO Arturo Gómez-Pompa, Andrea Kaus, Juan Jiménez-Osornio, David Bainbridge, and Veronique M. Rorive   483

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Sustainable Agriculture and the Environment in the HUMID TROPICS      THE PHILIPPINES Dennis P. Garrity, David M. Kummer, and Ernesto S. Guiang   549      ZAIRE Mudiayi S. Ngandu and Stephen H. Kolison, Jr.   625     GLOSSARY   659     AUTHORS   675     INDEX   679

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