i 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 ii 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 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 Agricultural systems—Tropics Sustainable agriculture—Tropics Land use, Rural —Tropics 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 not necessarily reflect the view of the organizations or agencies that provided support for this project Printed in the United States of America iii 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 iv 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 v 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 vi 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 chair man and vice-chai r man, respectively, of the National Research Council www.national-academies.org PREFACE vii 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 PREFACE viii (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 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 PREFACE ix 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 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 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 discusses technical research needs and presents recommendations on land use options Chapter 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 PREFACE x 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 INDEX ecological characteristics and issues, 399-400 economic activity, 400-401 economic importance of forestry, 402-405 forest fires, 415 forest resources, 397-399, 431-433 forestry programs, 179, 424-425 greenhouse gas emissions, 232 home gardens, 104-105, 106, 107 integrated pest management, 157 legislation and policies on forest resource management, 416-418 logging in natural forests, 39, 130, 164, 408-410, 420-422 permanent forests, 418-419 population, 45, 394-395, 406-408 reforestation and regreening programs, 422-424 shifting cultivation, 410-411, 424-428 Social Welfare Development for Isolated Societies program, 427 sustainable land use development programs, 415-431 timber production and wood-based industries, 402-403 transmigration program, 75, 189, 411-413, 426-427 tree crop development, 413-415 wet paddy rice agriculture, 429-431 Infrastructure building and forest clearance, 77, 127, 168 impact assessments, 168-169 and intensive agriculture, 71 investments, 16, 172, 177-178 and land tenure, 176 policy reforms, 164, 168-169, 177-178 Inga spp., 95, 96, 98 Integrated pest management, 157 Intensive cropping systems, 510 in agroforestry systems, 330-331 attributes of, 13, 140-141, 143 challenges in, 73, 75 690 characteristics of, 8-9 contour hedgerow systems, 76 crop diversity losses, 72 development of, 71-75 drained-field systems, 71 farming system methodologies, 72-73 and forest boundary stabilization, 77 inputs, 70, 72, 75 in lowlands, 70-71, 73, 75 mound systems, 71 potential productivity gains, 139 programs and research activities, 71-72, 75-77 and resource degradation, socioeconomic considerations, 73, 76 soil conservation in, 76, 99 soils appropriate for, 54, 55, 57, 70 sustainable, 9, 72-73, 76 terrace systems, 71, 74 uplands/steeply sloping areas, 72, 76 Inter-American Development Bank, 161 International agricultural research centers, 71-72, 76 International Center for Research in Agroforestry (ICRAF), 76, 185, 187, 524 International Institute of Tropical Agriculture (IITA), 71 International Livestock Center for Africa (ILCA), 76, 381 International Rice Research Institute (IRRI), 71, 76 International Tropical Timber Organization (ITTO), 161 Isoberlinia doka, 353 L Land abandoned, rehabilitation of, 16, 181-183 improvement, incentives to encourage investments in, 180-181 subsidies and rents, 165 transformation, examples, 67 see also Degraded lands Land tenure INDEX on abandoned lands, 16, 182 ancestral rights of indigenous occupants, 166, 167, 599-600 collective ownership, 175, 371-372 and deforestation, 42, 166, 370-372, 509 on extractive reserves, 135 and population growth rates, 597-598 private individual ownership, 372 property rights issues, 383-384 reforms, 16, 135, 150, 174-177, 598-599 regimes, 175, 370-372, 383-384 reinforcement of local stewardship through, 598-599 and resource degradation, 175 state ownership, 371 titling, 16, 169, 174-177 for small-scale farmers, 175 and sustainable resource management, 59-60, 132, 176-177 Land use abstract spatial consideration of patterns of, 248-249 alternative energy sources and, 190-191 approach to sustainability in, 64-65 attributes of systems compared, 139-144 and biomass maintenance, 152-153 biophysical attributes of, 139-140, 142 and carbon sinks, 251-252 in catchment areas, 158 classification systems, 150-152, 154 climate change and, 48-49, 102-103, 216-219 constraints on sustainability, 249 demographics and, 148 design and management considerations, 145-154 ecological guidelines for systems management, 154-155 economic attributes of systems, 141, 142-143 expansion potential of present systems, 339-342 factors affecting changes, 241-242 global equity considerations, 15, 172, 190 691 and global warming, 48-49, 102-103, 216-219, 252 and greenhouse gas emissions, 189-190, 219-238 impact assessments of infrastructure projects, 168-169 incentives for improvement of, 180-183 indigenous knowledge and production systems, 144-145 integrated approach to, 8, 62-64, 146-150, 164 knowledge about options, 139-145 monitoring systems and methodologies, 153-154 national-to-global model of impacts, 242-246 negative impacts of policies, 164-167 nonsustainable uses, 67 parameters for analyzing sustainability of, 304-305 and pest management, 155-157 policy review, 161-168 political and social stability and, 188-189 population growth and, 189 rates of change in, research needs, 158 scale considerations, 148-149 social attributes of systems, 141, 142 spatial arrangements of, 146-147, 246-248 sustainable, 3, 66-69, 138, 146-150, 218, 249-252, 415-431 technical needs common to all options, 155-158 temporal arrangements of, 147-148 transitional, 148 and water management, 158 zoning for, 149-150 Latin America agropastoral systems, 82-83 cattle pastureland, 87-89 deforestation, 35-38 forest cover, 36 INDEX humid tropical area, 23 income per capita, 41 reclamation of degraded pastureland, 73 see also individual countries Legumes bushy, 87 ground cover, 114 trees, 79 Lemon (Citrus limon), 106 Leucaena leucocephala, 87, 96, 97, 98 in contour hedgerow systems, 76, 99, 572-573 Livestock production in agropastoral systems, 82 in alley cropping, 381 buffalo, 82, 86 economic importance, 84, 86 forest conversion to, fowl, 82 genetic resistance to disease, 86-87 greenhouse gas emissions from, 225, 234 integration into farming systems, 157-158, 601-602 in mixed tree systems, 101 nutrient recycling by, 84, 157-158 sheep and goats, 87, 95 swine, 82, 83 trypanosomiasis in, 86-87 see also Cattle raising Local communities decision-making role of, 178-180 education and training for, 186-187 see also Indigenous people Logging, 45 access roads, 127, 129 ban, 163, 607 biomass losses from, 230, 231 and carbon cycling, 230-231 concessions, 165-166 controls on, 420-422 and deforestation, 5-6, 44, 68, 164, 230, 368, 408-410, 457-458, 646-647 dipterocarp trees, 126, 130-131 domestic, 640-641 692 economic benefits, 77 environmental damage from, 126, 230, 284 extraction rates, 230-231 fees, 163 financial incentives for, 163, 164, 165-166 and greenhouse gases, 49, 230-231 high-grading, 130-131 illegal, 167, 231 labor-based timber extraction, 595-596 land area under, 125 selective extraction, 126, 283-284 soil damage from, 126 unregulated commercial, 68, 646-647 see also Natural forest management Lowlands agropastoral systems, 82, 83 intensive cropping systems in, 70-71, 75 preservation programs, 75 rice production, 73, 75, 82, 83, 559 M Macambo (Theobroma bicolor), 104 Madagascar, 38, 179 Mahogany (Swietenia macrophylla), 116 Maize, 82, 83, 101, 151 Makoré (Tieghemella heckelii), 352 Malaysia agriculture, 6, 147, 445-447 biodiversity, 450-451, 470-471 deforestation, 6, 38, 68, 164, 167, 451-456, 473-475 economy (domestic), 445-447 forests, 38, 448-458 land use, 448 logging, 68, 126, 164, 457-458 manufacturing, 447 mixed tree systems, 105 natural forest management in, 127-128, 130 population, 443-445 research needs, 476-477 soil conservation, 467-468 topography, climate, and soils, 441-443 INDEX tree crop plantations, 6, 68, 113, 114, 458-471, 471-473 water systems protection, 468-470 Managed fallows and forests, 29, 80-81, 101, 103, 108, 125, 127, 132 Mango, 330, 332 Mangroves, 45 Manilkara spp., 103 Manioc, 104, 108 Merck and Company, 184 Methane flux from land-use changes, 234, 236-237 and global warming, 48, 219, 234, 236 sources, 48, 49, 224, 225, 234 Mexico agriculture, 151, 510, 522-523 agroforestry, 523-525 biodiversity management, 525-526 cattle ranching/livestock production, 68, 88, 506-507, 525 chinampa technology, 7, 520 colonization projects, 189, 507-508 deforestation, 38, 68, 88, 499-511, 523 development and conservation programs, 519-521 food and commodity production, 522-523 forest fires, 508-509 forest resources, 38, 496-498 greenhouse gas emissions, 232 history of land use, 484-485 home gardens, 104, 106-107 Huastec Maya, 518-519 improvement of resource management, 526-537 Lacandon Maya, 518 land use, 490-496 lowland Maya, 516-518 managed fallows and forests in, 80-81, 130 national security concerns, 509 Plan Puebla, 519-520 population, 484-485 protected areas, 511 road building and other engineering works, 511 reforestation, 523 693 secondary forests of Veracruz, 520-521 socioeconomic trends, 485-490 sustainable resource management, 511-526 timber exploitation, 510 traditional approaches to resource management, 515-519 tree ownership and land tenure problems, 509 Tropical Forestry Action Plan, 521-522 Milpas, 81 Mining, 43, 176 Mixed tree systems cultivation and management practices, 100-101, 151 ecological advantages of, 13, 105-106, 140-141, 143 economics of, 105, 109, 140-141, 329-330 kebun campuran, 107 managed fallows, 108 parak, 104 past and present forest management, 102-106 research on, 102, 109-110 role in tropical forest conservation, 10, 108-110 with shifting cultivation, 103 species cultivated in, 10, 104 sustainable, 110 talun-kebun, 107 types, 101 worldwide, 106-108 see also Forest gardens; Home gardens Models/modeling abstract spatial consideration of land use patterns, 248-249 carbon accounting, 238-241 national-to-global, 242-246 socioeconomic and ecological aspects of land use changes, 241-249 spatially explicit, 246-248 Modified forests, see Forests of humid tropics, modified INDEX Monocultural systems, 8, 59-60, 75, 101-102, 330-331, 333 Mound systems, 7, 71 Mulches and cover crops, 87, 114, 158, 379-380, 381 Multipurpose woodlots, 94 Myanmar, 38, 130, 232 N National Council of Rubber Tappers, 135 National policies enabling environment for sustainable agriculture, 15-16, 174-180 encouraging unsustainable land use, 162-163 infrastructure development, 164 land tenure, 166, 174-177 and livestock production, 88 mission of resource management agencies, 169-170 negative effects of, 163, 242 reforms, 163, 166-167 review needs and process, 163-166 tax incentives and credits, 88 National resource management agencies, 169-170 National security, and deforestation, 509 Natural forest management, 149 benefits and costs of, 11, 126-127, 140-141 and carbon cycling, 126-127, 140 Celos Management System, 130 constraints on, 125-126, 131-132 and forest regeneration, 127, 128, 129, 130 Malayan Uniform System, 127-128 Modified Selection System, 130 purpose of, 125 research and development, 130 selection systems, 129-131 Selective Logging System, 130 Selective Management System, 130 strip shelterwood systems, 128-129 sustainability of, 127, 131-132 Tropical Shelterwood System, 128 694 uniform shelterwood systems, 127-128 Necromass, 233-234 Nepal, 71, 75, 86 New York Zoological Society, 187 Niangon (Tarrietia utilis), 352 Nigeria, 37, 130 Nitrous oxide contribution to greenhouse effect, 219, 234 flux from land use changes, 237 sources, 48, 49, 234 Nongovernmental organizations (NGOs), education and training role, 17, 186-187 No-till systems, 185, 382 Nuclea latifolia, 98 Nutmeg, 105 Nutrient cycling in agropastoral systems, 83-84 in alley cropping, 381 comparison of land use systems, 140, 142 in forests, 32 integrated management of, 157-158 land use and, 157-158 in monocultural systems, 60 and productivity, 154, 157-158 in regenerating forests, 120-121, 123, 140-141 research on, 88 in shifting agriculture, 77-78 in soils, 55-56 in tree plantations; 116, 140, 142 O Oil palm production, 11, 113, 114, 128, 274, 330, 332 Orange (Citrus aurantium), 106 Orchards, 101, 108 P Palm Oil Research Institute of Malaysia (PORIM), 114 Panama, 104 Panicum maximum, 89 Papaya (Carica papaya), 106, 330 INDEX Paper Industries Corporation of the Philippines (PICOP), 94 Paricá (Schizolobium amazonicum), 333 Paspalum spp., 120 Passion fruit, 330, 331 Pastureland African, 86-87 area of, 233 Asian, 86 biomass losses from burning, 233 cattle, 86-88 degradation, 89, 90, 224, 225 forest conversion to, 6, 68, 85, 88, 162, 164, 224, 316-320 grass-legume mixture, 88 and greenhouse gases, 224-225, 237 knowledge about, 294 Latin American, 87-90, 294 nutrient cycling on, 88, 225 productivity, 225 reclamation of degraded pasture on deforested lands, 73, 90 technology for sustainability, 91-92 weed invasion, 89 Peach palm (Bactris gasipaes), 104, 183, 330 Perennial crop agriculture land tenure and, 582 progress in, 293-294 research needs, 328 sustainability of, 68, 326-328 Perennial tree crop plantations, 110-115, 582 Peru alley cropping in, 576 cattle raising, 88 deforestation, 38, 61, 88 indigenous people, 104, 108, 129 intensive cropping systems, 70 mixed tree systems, 104, 108 natural forest management in, 129 overexploitation of forest products, 136 Pichis-Palcazu Project, 169 soil management practices, 61 Pest management and agricultural productivity, 57-58, 155-157, 287 comparison of land use systems, 140 695 with cropping systems, 83 in home gardens, 101 integrated, 157 intensive cropping and, 70, 75 land use and, 155-157 Pesticide use, 60, 70, 156 Philippines, 71 agriculture, 44, 556-557, 559-560, 570-584, 600-601 agroforestry systems, 94-95 community-based resource management, 179-180, 591-595, 598-599, 607-608 contour hedgerow systems, 571-579 dam projects, 169 deforestation, 38, 44, 164, 167, 560-569, 609-612 diversification into mixed farming systems, 583-584 fallow improvement systems, 587-589 fire ecology and management, 591 foreign aid to, 608-609 forest management, 130, 179-180, 592-596, 602, 607-608 forest types, 560-562 fuelwood use, 44 grasslands and brushlands, 584-592 indigenous communities' role and rights, 176, 592-593, 599-600 institutional changes, 606 land tenure, 166, 176, 586-587, 597-600 land use, 552-554 livestock production, 601-602 logging, 44, 607 migration to uplands, 557-558 nutrients for soils, 580-582 perennial crops, 582 permanently farmed sloping lands, 570-584 phosphorus sources for soils, 581-582 physical environment, 551-552 political corruption in, 167 population growth and pressures, 86, 554-555, 597-598 reduced-tillage systems, 579-580 reforestation efforts, 589-591 INDEX research needs, 602-606 resettlement policies and programs, 189 rice production in lowlands, 559 shifting agriculture, 86 Sloping Agricultural Land Technology Program, 76 sustainable land use approaches in uplands, 569-612 technology development and dissemination, 600-606 timber concessions, 568-569 timber pricing reform, 607 tree crops, 582-583 upland ecosystem, state of, 551-560 Pineapple (Ananas spp.), 107, 110, 330, 331 Pinus spp., 115, 116, 332 Plantains (Musa spp.), 82, 101, 107 Plantation agriculture components of, 110-111 crop characteristics, 10, 112 and economic development, 111-113 public management of, 112 sustainable management methods, 114 see also Tree crop plantations Plantation forestry, 10, 115-118, 140-141, 143-144, 229 Policies, see Development assistance policies ; National policies Political and social stability, and land use, 167, 188-189 Population and agriculture, 59 in countries with tropical moist forests, 24-26, 40 and deforestation, 45, 406-408, 647-649 growth rates, 41 issues in tropics, 40-41 and land tenure, 597-598 and land use policies, 103, 189, 241 and shifting cultivation, 78-79, 103, 148 696 Poverty alleviation programs, 76, 145 debt burden of developing countries, 41 plantation agriculture and, 111 and sustainable land use, 40 Private voluntary organizations, 186 Property rights, 166-167 Protected areas attributes, 144 biodiversity management in, 170-171, 525-526 extractive reserves, 134-137, 171 forest patches, 103, 108 forestry projects, 187 Kibale Forest Reserve, 187 land area, 133, 511 mechanisms for protection, 11, 133, 511 size and configuration of, 133, 150 social and ecological pressures on, 133-134 Puerto Rico, 225 Q Quercus spp., 103 R Rainfall, and soil loss, 32-33 Rambutan (Nephelium lappaceum), 106 Rattan, 136 Recommendations biodiversity conservation, 170-171 biomass maintenance, 152-153 design and selection of land uses, 146-150 enabling environment for sustainable agriculture, 15-16, 174-180 equitable distribution of conservation costs, 15, 172, 190 goals of, 159-160 incentives for land improvement, 16, 180-183 infrastructure development, 16, 168-169, 177-178 land titling and land tenure reforms, 174-177 INDEX local participation in development planning, 178-180 mission of national resource management agencies, 169-170 NGO role, 17, 186-187 policy reviews, 14-15, 161-167 see also Research needs and approaches Reforestation and carbon flux, 103, 240 contract programs, 589-591 extent of, 39 on grasslands, 589-591 projects, 422-424 Regenerating forests, see Forest regeneration Regreening programs, 422-424 Research needs and programs agriculture, 62-64, 291-292, 600-601 agroforestry, 99-100, 333, 523-524 agropastoral systems, 84-85, 91-92 biodiversity, 171 climate change related to land use changes, 102, 252 commodity-specific, 62-63, 158 documentation of land use system, 13, 150-152 extension programs, 85, 187-188 extractive reserves, 135-136, 137 floodplain agriculture, 316 forest conversion, 46 forest reserves, 133, 135-136, 171 forestry, 109-110, 602 institutional capacity for fulfilling, 84-85, 336 integrated approach, 62-64 intensive cropping systems, 71-72, 75-77 international partnerships, 16-17, 185, 605-606 land attributes, 150 livestock production, 87, 320, 601-602 methodology development, 184-185, 602-605 mixed tree systems, 102, 109-110 monitoring systems and methodologies, 14, 153-154 697 natural forest management, 130 NGO role, 17, 186-187 nontimber resource extraction, 308 perennial crop agriculture, 114-115, 293 preservation of indigenous knowledge, 13-14, 144-145 progress in, 295 shifting agriculture, 312 social science, 76 soil-plant-animal grazing trial, 88 soils, 100 taxonomy of forest species, 30 timber extraction, 311 traditional land use systems, 63, 99, 144-145 tree crop plantations, 114-115, 118 Rice plant hopper, 157 Rice production, 86, 107 agropastoral systems, 82, 83 greenhouse gas emissions from, 48, 224, 234, 237 intensive cultivation, 73, 75 knowledge base on, 293 and land ownership, 59 lowland, 73, 75, 82, 83, 559 monoculture, 75 in shifting agriculture, 82 soils used for, 57 sustainability of, 223-224 terraces, 74 wet paddy agriculture, 7, 70-71, 223-224, 429-431 Rubber, 11, 111, 113, 114, 128, 135, 136, 274, 280, 330, 331, 332 Rubber Research Institute of Malaysia, 114 Rwanda, agroforestry systems, 94, 95 S Sahel, soils, 54 Samanea saman, 98 Samba (Triplochiton scleroxylon), 352 Sapodilla tree (Achras zapota), 135 Secondary forests area of, 39, 123 benefits, 10, 30, 118, 119, 140-141, 144 biological diversity in, 81 INDEX carbon cycling, 30, 49, 103, 228, 231 characteristics, 29, 124 clearance for low-input cropping, 82 defined, 122 fires, 121 growth rates, 182 in situ experimental research, 520-521 and shifting cultivation, 123 sustainable use of, 10, 61, 123-125, 330, 331 tree species in, 123 Sedimentation, 46-47, 169 Shifting cultivation, 45 agricultural programs affecting, 425-426 agroforestry and, 94, 100, 101, 103 agropastoral systems, 83, 88 attributes of, 140-141 and biomass maintenance, 153 carbon losses from, 225-226, 246, 247 categories of, 41-42, 77 defined, 77 and deforestation, 41, 173-174, 226, 370, 409-411 encroaching cultivation, 228-229 fallow period, 9, 78-80 and forest regeneration, 81, 120-121 forestry programs affecting, 424-425 and greenhouse gases, 225-229 land ownership and, 175 low-input cropping, 81-82 managed fallows and forests, 80-81, 101 multiple cropping arrangements, 79-80 and nutrient cycling, 77-78, 79 population pressures and, 78-79, 103, 148 rationalization of, 424-428 research needs, 314 short-rotation, 8, 9, 86, 173-174, 226-228 slash-and-mulch, 77-78 social welfare program for isolated societies, 427 soil management practices, 79 soils used for, 54, 55, 81, 86 698 stabilization guidelines, 9, 79-80 sustainability of, 78, 225-226, 227-228, 313-314 traditional, long-rotation, 7-8, 9, 41, 59, 68, 78, 94, 140-141, 143, 225-226 transmigration and, 9, 41-42, 59, 426-428 Shorea spp., 127 Silviculture, 125, 127, 131 Silvopastoral systems, 68, 93-94, 229, 332-333 Social forestry programs, 179-180, 251 Sociocultural conditions, and sustainable agriculture, 288-289 Socioeconomic factors comparison of systems, 141-143 conversion of forests, 49-51 documentation needs, 13, 152 in infrastructure building, 169 in land use changes, 241-242 models, 242-249 monitoring, 153-154 spatial patterns of land use and, 147 and sustainability of land use, 249 Soil conservation in agrisilvopastoral systems, 95 agroforestry and, 380, 381 comparison of land use systems, 140, 143 in contour hedgerow systems, 99, 381 intensive cultivation and, 76 methods, 113 organic matter management, 79, 114 and productivity, 154-155 tree crop plantations and, 114, 467-468 Soil degradation agricultural inputs and, 75 alley cropping and, 99 conversion of forests and, 46, 50 deforestation and, 38-39, 56-57 logging and, 126 monitoring, 14, 153 pastureland, 89 INDEX reversal of, shifting cultivation and, 79 from tree crop plantations, 113 Soils of the humid tropics and agricultural productivity, 1-2, 53-57, 575-576 Alfisols, 99, 100 aluminum toxicity, 55, 57, 575-576 calcium content, 56, 57, 99 carbon content, 220, 221, 224, 226, 233-234 characteristics, 23, 27-28 classifications, 152, 293 data availability on, 14, 153 deforestation effects on, 56-57 Entisols, 27, 57 forest, 32, 56-57 geographic distribution, by order, suborder, or type, 23, 27, 53-55 greenhouse gas emissions from, 234, 237 Inceptisols, 27, 57 for intensive cropping, 54, 55, 57, 70 iron compounds, 57 laterite formation, 54-55 magnesium content, 56, 99 misconceptions about, 54-56 Mollisols, 55 nitrogen content, 56, 89, 99, 237, 576 nutrient cycling, 23 55-56, organic matter content, 23, 55, 99, 116, 225, 379, 576 Oxisols, 23, 27, 54, 55-56, 70, 249 pH, 99 phosphorus content, 56, 57, 89, 99, 576 potassium content, 57, 99 research needs, 100 and sustainable agriculture, 53-57, 287-288 Ultisols, 23, 27, 55-57, 70, 249, 576 South America soils, 23, 53, 54 see also Latin America; individual countries Southeast Asia 699 forest harvest intervals, 166 forest regeneration on grasslands, 120, 121, 123 range of land use systems, 152 social forestry programs, 179-180 see also individual countries Spondias spp., 103 Sri Lanka, 107, 112 Star apple (Pouteria caimito), 104 Steeply sloping areas, see Uplands/ steeply sloping areas Subsidies, and adoption of technology, 90 Sugarcane (Saccharum officinarum), 107, 110 Suriname, 125, 130 Sustainable agriculture agroforestry and, 380-382 in agropastoral systems, 84-85 basis for, 64-65 benefits of, 61-62, 160 biological constraints on, 57-58 biotic pressure and, 287 and carbon releases, 247 characteristics of, 22 climate and, 286-287 conservation tillage, 382 constraints on agricultural productivity, 52-58 credit access for small-scale farmers, 177 defined, 66 design and management considerations, 145-146 development assistance policies and, 51 diversification and, 3-4 enabling environment for, 174-180 environmental bottlenecks to, 290-291 external factors in, 250 fertilizer use in, 380 and greenhouse gas emissions, 189-190 incentives and opportunities for, 180-188 infrastructure investments and, 177-178 institutional and policy changes, 84-85 INDEX intensification in, 72-73 interventions, 377-385 labor-intensive mixed cropping systems, 68 land tenure reforms and, 59, 174-177 local decision making and, 178-180, 591-592 markets for products, 183-184 mixed farming systems, 583-584 mulches and cover crops, 379-380 nutrient sources, 560-562 organic matter for soils, 379 pathways to, 58-62, 69 perennial crops, 68, 582 phosphorus sources, 581-582 political considerations, 289-290 practices associated with, 60-61 reduced-tillage systems, 579-580 research, development, and knowledge transfer, 184-188 sociocultural conditions and, 288-289 soils and, 53-57, 287-288 supporting, 173-188 technological interventions and, 377-382 traditional methods, 58-59 transition to, 61 see also Agricultural productivity; Contour hedgerow systems Sustainable resource management barriers to, 1-2 characteristics of, chinampa technology, 520 definition of, 511-513 demonstration projects, 533-534 determinants of, 138 education in, 532-533 employment opportunities and, 50 global requirement for, 4-5 by Huastec Maya, 518-519 implementation of, 534-536 by Lacandon Maya, 518 by lowland Maya, 516-518 Plan Puebla, 519-520 policy issues, 527-529 700 practices in Mexican humid tropics, 513-515 research needs, 529-532 secondary forests, 520-521 secondary problems, 536-537 traditional approaches, 515-519 Sweet potato (Ipomoea batatas), 107 Swietenia spp., 115, 116 T Tatajuba (Bagassa guianensis), 333 Tax incentives and credits, 88, 164, 172 Tea plantations, 112 Technology agroindustrial, 294-295 and deforestation, 388 diffusion and utilization, 90, 295-296, 600-606 interventions, 377-382, 388 local decision making on, 178-180 for reclamation of pastureland, 90, 91-92 and resource degradation, 9, 75 success factors, 148 and sustainable agriculture, 143, 377-382 Tectona spp., 115 Terrace systems, 7, 71, 74, 114, 147, 148 Thailand, 71, 86, 108, 232 Tillage practices, 158 Timber and timber products concessions, 167 economic importance of, 45, 402-403 exploitation of, and deforestation, 164, 376-377, 510, 568-569 extraction of, 39, 129, 308-311, 595-596; see also Logging; Natural forest management harvest intervals, 166 industrial roundwood production, 639 labor-based timber extraction, 595-596 potential, 376-377 pricing reform, 165, 167, 607 species important for, 352 research needs, 311 INDEX sustainability of extraction, 310-311 Trade reforms, 172 Transmigration and deforestation, 160, 411-413 and intensive cropping, 9, 75 and shifting cultivation, 9, 41-42, 59, 426-428 sustainable agriculture and, 160 Tree crop plantations, 136 age factors, 116 and biodiversity, 113, 450-451, 470-471 biomass production in, 115, 116, 153, 229 common characteristics, 115, 140-141, 142-143 and deforestation, 68, 413-415 ecologic benefits of, 29, 115-116, 140, 142, 143-144 and economic development, 11, 113, 329-330 economic feasibility of, 141, 142-143, 461-463 environmental effects, 103, 113-114, 466-471 farm forestry, 582-583 and greenhouse gases, 229 inputs, 114 intercropping on, 229 investments for sustainability, 114-115 land area, 115 management, 117-118 mixed, 107 monocultures, 101-102, 229 nutrient cycling in, 116, 140, 142, 157, 229 perennial, 6, 10, 11, 107, 110-115, 140-141, 142-144, 157, 582 policies affecting expansion of, 463-466 productivity, 115-116 prospects for, 471-473 research and development, 114-115, 118 with secondary crops, 75 small-scale production, 101-102 and soil conservation, 467-468 species used in, 115, 117-118 701 sustainability of land use for, 10, 68, 110, 229, 459-461 uses, 115, 116, 117, 191 and water systems protection, 468-470 Trees agroforestry species, 96-98, 330-331 alley cropping species, 524-525 biomass production, by species, 97 coppicing, 81, 96 for forest regeneration, 123 fruit, in humid tropics, 104 leguminous/nitrogen fixing, 95, 79, 96, 98 marketable species, 125-126, 333, 352 with negative effects on soils, 98-99 plantation species, 115, 116-117 from stem cuttings, 98 Trinidad, 130 Tropical Forestry Action Plan, 165-166, 521-522 Tropical moist deciduous forests, extent of, 35 Tropical rain forests, extent of, 35 Tropical zone, forested bioclimesin, 28 Trypanosomiasis, 86-87 Tsetse fly control, 86, 87 U Uapaca togoensis, 353 Uganda, 130, 187 United Nations Development Program, 166 Environment Program, 154 Uplands/steeply sloping areas deforestation of, 45 intensive cropping systems on, 72-73, 76 land use patterns on, 151, 249 livestock integration into farming in, 381, 601-602 no-tillage agriculture on, 185 soil conservation on, 76 terracing on, 148 Urban population, 24-26 Urucu, 330, 332 INDEX U.S Agency for International Development, 187 Uvillia (Pourouma cecropifolia), 104 V Vanilla, 104 Venezuela, 38, 120-121, 160, 225 W Water availability and quality, forest conditions and, 33 conservation, 140 control systems for intensive agriculture, 71 management, land use and, 158 pollution, 75 systems, protection of, 468-470 Waterborne diseases, 33, 75 Watersheds, protective role of forests, 32-33 Weather, storm mitigation by forests, 33 Weed suppression, 287, 380 West Africa soils, 54 tree crop plantations, 114 Wetlands, cultivation of, 75, 237 Women, land tenure, 176 Wood-based industries economic importance of, 402-403 primary, 402 secondary, 402-403 World Bank, 161, 166, 169, 172 World Resources Institute, 166 X Xate (Chamaedorea spp.), 135 Y Yam (Dioscorea trifida), 82, 107 Z Zaire advancement of agricultural frontiers, 645 agriculture, 156, 652-653 climate, 627 deforestation, 38, 641-649 extension service, 653 extractive reserves, 149 forest management, 130, 149, 637-639, 652-653, 656 forest resource distribution, 635-637 forest types, 626 fuelwood demand and harvesting, 191, 645-646 funding for sustainable management, 656 human resources development, 653-655 702 industrial roundwood production, 639 institutional arrangements and possible reforms, 649-652 land tenure, 627, 634, 656 logging, 640-641, 646-647 macroeconomic setting, 634-635 natural resources, 625 population, 627, 634, 647-649 research agenda, 652-653 society and culture, 627, 634 sustainable management suggestions, 652-656 tax policies and investment procedures, 639-641 RECENT PUBLICATIONS OF THE BOARD ON AGRICULTURE POLICY AND RESOURCES Agriculture and the Undergraduate: Proceedings (1992), 296 pp., ISBN 0-309-04682-3 Water Transfers in the West: Efficiency, Equity, and the Environment (1992), 320 pp., ISBN 0-309-04528-2 Managing Global Genetic Resources: Forest Trees (1991), 244 pp., ISBN 0-309-04034-5 Managing Global Genetic Resources: The U.S National Plant Germplasm System (1991), 198 pp., ISBN 0-309-04390-5 Sustainable Agriculture Research and Education in the Field: A Proceedings (1991), 448 pp., ISBN 0-309-04578-9 Toward Sustainability: A Plan for Collaborative Research on Agriculture and Natural Resource Management (1991), 164 pp., ISBN 0-309-04540-1 Investing in Research: A Proposal to Strengthen the Agricultural, Food, and Environmental System (1989), 156 pp., ISBN 0-309-04127-9 Alternative Agriculture (1989), 464 pp., ISBN 0-309-03987-8; ISBN 0-309-03985-1 (pbk) Understanding Agriculture: New Directions for Education (1988), 80 pp., ISBN 0-309-03936-3 Designing Foods: Animal Product Options in the Marketplace (1988), 394 pp., ISBN 0-309-03798-0; ISBN 0-309-03795-6 (pbk) Agricultural Biotechnology: Strategies for National Competitiveness (1987), 224 pp., ISBN 0-309-03745-X Regulating Pesticides in Food: The Delaney Paradox (1987), 288 pp., ISBN 0-309-03746-8 Pesticide Resistance: Strategies and Tactics for Management (1986), 480 pp., ISBN 0-309-03627-5 Pesticides and Groundwater Quality: Issues and Problems in Four States (1986), 136 pp., ISBN 0-309-03676-3 Soil Conservation: Assessing the National Resources Inventory, Volume (1986), 134 pp., ISBN 0-309-03649-9; Volume (1986), 314 pp., ISBN 0-309-03675-5 New Directions for Biosciences Research in Agriculture: High-Reward Opportunities (1985), 122 pp., ISBN 0-309-03542-2 Genetic Engineering of Plants: Agricultural Research Opportunities and Policy Concerns (1984), 96 pp., ISBN 0-309-03434-5 NUTRIENT REQUIREMENTS OF DOMESTIC ANIMALS SERIES AND RELATED TITLES Nutrient Requirements of Horses, Fifth Revised Edition (1989), 128 pp., ISBN 0-309-03989-4; diskette included Nutrient Requirements of Dairy Cattle, Sixth Revised Edition, Update 1989 (1989), 168 pp., ISBN 0-309-03826-X; diskette included Nutrient Requirements of Swine, Ninth Revised Edition (1988), 96 pp., ISBN 0-309-03779-4 Vitamin Tolerance of Animals (1987), 105 pp., ISBN 0-309-03728-X Predicting Feed Intake of Food-Producing Animals (1986), 95 pp., ISBN 0-309-03695-X Nutrient Requirements of Cats, Revised Edition (1986), 87 pp., ISBN 0-309-03682-8 Nutrient Requirements of Dogs, Revised Edition (1985), 79 pp., ISBN 0-309-03496-5 Nutrient Requirements of Sheep, Sixth Revised Edition (1985), 106 pp., ISBN 0-309-03596-1 Nutrient Requirements of Beef Cattle, Sixth Revised Edition (1984), 90 pp., ISBN 0-309-03447-7 Nutrient Requirements of Poultry, Eighth Revised Edition (1984), 71 pp., ISBN 0-309-03486-8 More information, other titles (before 1984), and prices are available from the National Academy Press, 2101 Constitution Avenue NW, Washington, DC 20418 USA, 202/334-3313 (information only); 800/624-6242 (orders only); 202/334-2451 (fax) RECENT PUBLICATIONS OF THE BOARD ON SCIENCE AND TECHNOLOGY FOR INTERNATIONAL DEVELOPMENT ENERGY Alcohol Fuels: Options for Developing Countries (1983), 128 pp., ISBN 0-309-04160-0 Producer Gas: Another Fuel for Motor Transport (1983), 112 pp., ISBN 0-309-04161-9 The Diffusion of Biomass Energy Technologies in Developing Countries (1984), 120 pp., ISBN 0-309-04253-4 TECHNOLOGY OPTIONS Priorities in Biotechnology Research for International Development: Proceedings of a Workshop (1982), 261 pp., ISBN 0-309-04256-9 Fisheries Technologies for Developing Countries (1987), 167 pp., ISBN 0-309-04260-7 Applications of Biotechnology to Traditional Fermented Foods (1992), 199 pp., ISBN 0-309-04685-8 PLANTS Amaranth: Modern Prospects for an Ancient Crop (1983), 81 pp., ISBN 0-309-04171-6 Jojoba: New Crop for Arid Lands (1985), 102 pp., ISBN 0-309-04251-8 Quality-Protein Maize (1988), 130 pp., ISBN 0-309-04262-3 Triticale: A Promising Addition to the World's Cereal Grains (1988), 105 pp., ISBN 0-309-04263-1 Lost Crops of the Incas (1989), 415 pp., ISBN 0-309-04264-X Saline Agriculture: Salt-Tolerant Plants for Developing Countries (1989), 150 pp., ISBN 0-309-04266-6 INNOVATIONS IN TROPICAL FORESTRY Mangium and Other Fast-Growing Acacias for the Humid Tropics (1983), 63 pp., ISBN 0-309-04165-1 Calliandra: A Versatile Small Tree for the Humid Tropics (1983), 56 pp., ISBN 0-309-04166X Casuarinas: Nitrogen-Fixing Trees for Adverse Sites (1983), 118 pp., ISBN 0-309-04167-8 Leucaena: Promising Forage and Tree Crop for the Tropics (1984), 2d ed., 100 pp., ISBN 0-309-04250-X Neem: A Tree that Could Help the World (1992), 149 pp., ISBN 0-309-04686-6 MANAGING TROPICAL ANIMAL RESOURCES Butterfly Farming in Papua New Guinea (1983), 36 pp., ISBN 0-309-04168-6 Crocodiles as a Resource for the Tropics (1983), 60 pp., ISBN 0-309-04169-4 Little-Known Asian Animals with a Promising Economic Future (1983), 133 pp., ISBN 0-309-04170-8 Microlivestock: Little-Known Small Animals with a Promising Economic Future (1990), 449 pp., ISBN 0-309-04265-8 RESOURCE MANAGEMENT Environmental Change in the West African Sahel (1984), 96 pp., ISBN 0-309-04173-2 Agroforestry in the West African Sahel (1984), 86 pp., ISBN 0-309-04174-0 Conserving Biodiversity: A Research Agenda for Development Agencies (1992), 127 pp., ISBN 0-309-04683-1 Additional titles and ordering information are available from the Board on Science and Technology for International Development, Publications and Information Services (FO-2060), Office of International Affairs, National Research Council, 2101 Constitution Avenue NW, Washington, DC 20418 USA, 202/334-2688 ... 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 EXECUTIVE SUMMARY 18 19 PART ONE 20 AGRICULTURE AND THE ENVIRONMENT IN THE HUMID TROPICS 21 Agriculture and the Environment in the Humid Tropics The wide belt of land and. .. Requirement The Humid Tropics Sustainable Land Use Options Recommendations Conclusion 12 17 PART ONE AGRICULTURE AND THE ENVIRONMENT IN THE HUMID TROPICS The Humid Tropics Forest Characteristics and