biophysical research for asian agroforestry

289 Pages·2010·6.37 MB·English

BIOPHYSICAL RESEARCH FOR

ASIAN AGROFORESTRY

Editors
MARTHA E.AVERY

Forester, Argonne National Laboratory, USA

MELVIN G.R. CANNELL

Head of Station, Institute of Terrestrial Ecology, Scotland

CHIN K. ONG

Agronomist, ICRISAT, India

WINROCK INTERNATIONAL, USA

and

SOUTH ASIA BOOKS, USA
This volume was sponsored by the Forestry/Fuelwood Research and
Development (F/FRED) Project for which Winrock International is the
principal contractor. Funded by the U.S. Agency for International
Development, the F/FRED Project is designed to help scientists in Asia
address the needs of small-scale farmers for fuelwood and other tree products.
F/FRED provides a network through which biological and social scientists
exchange research plans, methods, and results. The books in this series are
designed to further stimulate internationpl efforts to improve the productivity
and effectiveness of agroforestry research, in meeting increasing human and
environmental needs.
To facilitate access to literature cited in this book, copies of most of the articles
(but not books) are available on request from:
Research Network Secretary
P.O. Box 1038
Kasetsart Post Office
Bangkok, 10903, Thailand
C 1991 Winrock International, USA
ISBN 0.933595.32.8
In collaboration with South Asia Books, USA, originally published in India
by Mohan Primlani, Oxford & IBH Publishing Co. Pvt. Ltd., 66 Janpath,
New Delhi 110 001, (or the Winrock -Oxford & IBH Series, phototypeset by
Indira Printers and printed at Rekha Printers Pvt. Ltd., A-102/1 Okhla
Industrial Area, Phase I1,New Delhi 110 020.
Foreword
Winrock International Institce for Agricultural Development and the
Oxford and IBH Publishing Company began publishing a book series on
agroforestry research and practice in 1990. The first volume, A Handbook
for Managing Agroforestry Research, was written by Dr. John Gordon, Dean
of the Yale School of Forestry and Environmental Studies, and myself.
This is the second volume in the series. The editors, Dr. Martha Avery,
Dr. Melvin, Cannd.ll and Dr. Chin Ong, have organized our current
understanding of agroforestry systems in terms of biological concepts. We
believe this conceptual structure will help research specialists and
practitioners in framing clearer, more readily testable, and ultimately
more useful hypotheses about how agroforestry svstents work and how
they might be improved.
Other volumes in this series will integrate the ;ocial sciences into our
tinderstano ig of agroforestry and develop more locational specific
understanding of particular systems. At present we plan on publishing ten
or more volumes on agroforestry over the next three years.
We have three goals in this series. We want each volume to be
relevant to the problems faced by researchers and practitioners, but we
are especially concerned that the volumes lead toward results of benefit
to rural poor people throughout Asia. Our authors and ediors are working
hard on the quality of their expression as well as the quality of their
ideas, s each volume can be easily understood and translated into
practice.
Finally, we want the price of each volume to be within reach of
students, resear-:hers, and practitioners. We are most grateful to the U.S.
Agency for International Development for supporting the i'irst three
volumes of this series through its F/FRED Multipurpose Tree Species
Network Project being managed by Winrock International. The Ford
Foundation and other dolors are supporting future volumes, and we are
searching for additional support.
General Series Editor WILLIAM R. BENTLEY
April 1991
Preface

The purpose of this volume is to provide a framework for examining some of the
biophysical principles underlying agroforestry. Arguments in favor of growing
trees with agricultural crops are often based on untested assumptions, and many
of the critic3l biological issues have not been addressed previously. This vojume
differs from others in that it focuses on evaluating rather than describing
agroforestry systems.
The chapter authors were requested to identify the critical research
questions in their fields and then to outline ways for researchers to conduct
experiments to address those questions. Some authors responded by restating
the questions as testable hypotheses and including sections on the client
problem, hypothesis, materials and methods, and critical review. Other authors
responded more generally, addressing the critical questions in terms of basic
principles. Whichever approach was used, the charge was to assess which
th !ories have actually been proven and which remain as assumptions, then to
offer direction for future research. The specific research examples in this volume
illustrate many of the concepts presented in the companion volume (volume 1)
on research methods.
Conceived essentially as a handbook for new researchers and practitioners
in the field of agroforestry, this volume includes chapters on experimental
design specifically for agroforestry research; design elements of agroforestry
systems; and chapters investigating plat-t, soil, and livestock interactions. The
chapters on allelopathy and biological control can draw on little specific
agroforestry research and thus anticipate areas of increasing interest.
Several chapters were solicited to present less common perspectives on
agroforestry research and application. The social implications of biophysical
research are addressed in the chapter by Hocking, who contends that social
objectives are influenced by the specific biophysical research conducted. His
chapter reinforces the relationship between the biological and social sciences
and serves as a bridge to the companion volume (volume 3) on sociocultural
research. The chapter by Jones and Lowry is unusual in that it approaches the
objective of increasing fodder availability by improving fodder quality and
digestibility, not by increasing the biomass yield from agroforestry systems. The
chapter by Briscoe goes beyond small farm agroforestry systems to explore
silvicultural applications for industrial and government lands.
The production of this volume has involved many people in numerous
countries. We would Pl.e to thank the chapt r authors for their willingness to
address agroforestry research from our pa:ticular perspective and the many
colleauges who reviewed and commented on the various chapters. We would
like to formally acknowledge the institutional support provided by Winrock
International and the individual efforts of William R. Bentley, managing editor
viii Preface
of the handbook series, Karen Seckler, editorial consultant for this volume,
and Barbara Scott for her tireless secretarial support.
MARTHA E. AVERY
MELVIN G.R. CANNELL
CHIN K. ONG
Contents

FOREWORD: William R. Bentley v

PREFACE vii

CONTRIBUTING AUTHORS xiii

PART ONE: APPROACHING AGROFORESTRY
I DESIGNING EXPERIMENTS FOR AGROFORESTRY 3

RESEARCH

R. Mead
General Statistical Principles of Design Relevant to Ag-oforestry 3

Research

Components of Design for Agroforestry Experiments on Research 5

Stations

A Philosophy for On-farm Experimentation 17

2. ORIENTING AGROFORESTRY RESEARCH TOWARD 21

SOCIAL OBJECTIVES

D. Hocking
Definitions 22

Research is not Neutral: Two Examples in Agroforestry 22

Methods of Social Audit for Agroforestry Research 24

Social Objectives: Explicit and Implicit 29

Case Studies 31

Conclusions 33

Appendix: Glossary of Terms 36

PART TWO: DESIGNING AGROFORESTRY SYSTEMS
3. TREE SELECTION AND IMPROVEMENT FOR 41

AGROFORESTRY

L. Chuntanaparband K.G. MacDicken
State of Tree Improvement in Asia 42

Approaches to Tree Improvement for Agrcforestry 42

Tree Selection Criteria for Agroforestry 50

Conclusions 56
x Contents
4. PLANT MANAGEMENT IN AGROFORESTRY 59

M.G.R. CanneU
Manipulating Trees 59

Manipulating Tree/Crop Mixtures 63

Conclusions 70

5. BIOLOGICAL CONTROL OF INSECT PESTS AND PLANT 73

DISEASES IN AGROFORESTRY SYSTEMS

Zhao Lping

Effects of Vegetational Diversity 73

Evaluating Polyculture Systems for Pest and Pathogen Reduction 76

Disease Reduction in Mixed Cropping Systems 80

Designing Agroforestry Systems for Biocontrol 83

Conclusions 87

6. SILVICULTURAL APPLICATIONS OF AGROFORESTRY 91

C.B. Briscoe
Large Ownership 91

Agroforestry to Increase Management Efficiency 93

Agroforestry for Industrial Self-sufficiency 95

Agroforestry for Social Objectives 97

Future Research Directions 100

Appendix 102

PART THREE: INVESTIGATING BIOLOGICAL INTERACTIONS
7. INTERACTIONS OF LIGHT, WATER, AND NUTRIENTS 107

IN AGROFORESTRY SYSTEMS

C.K. Ong
Biophysical Concepts of Crop Productivity 107

Environmental Modifications 113

Land Equivalent Ratio 113

Agroforestry Examples 114

Interaction for Moisture 118

Summary 120

Future Research Directions 121

8. NITROGEN-FIXING PLANT INTERACTIONS IN 125

AGROFORESTRY SYSTEMS

M.E. Avery
Availability of Fixed Nitrogen to the Companion Crop 126

Woody Perennials as a Source of Biological Fixed Nitrogen 134

Conclusions 139
Contents xi

9. SOIL MICROORGANISMS IN AGROFORESTRY SYSTEMS 143

C.T. Wheeler, I.M. Miller, R. Narayananand D. Purushothaman
Symbiotic Nitrogen Fixation in Agroforestry Systems 143

Role of Mycorrhizas in Agroforestry Systems 155

Other Microorganisms 160

Conclusions 161

10. ALLELOPATHY 167

S.B. Horsley
Separating Allelopathy from Competition and Other Influences 168

Allelopathy and Intercropping 170

Allelopathy and Mulching 174

Future Research Directions 178

PART FOUR: MANAGING THE SOIL
11. SOIL FERTILITY 187

A. Young
Research Questions on Soil-agroforestry Interactions 189

Future Research Directions 204

12. SOIL EROSION AND CONSERVATION IN 209

AGROFORESTRY SYSTEMS

K.F. Wiersum
Erosion Control Through Agroforestry 210

Objectives of Erosion Research in Agroforestry 214

Research Methods 215

Observational Studies of Erosion 217

Experimental Studies of Erosion 224

Erosion Predict:on Models 227

Furure Research 229

PART FIVE: INTEGRATING LIVESTOCK
13. LIVESTOCK IN AGROFORESTRY: A FARMING 233

SYSTEMS APPROACH

L. Reynolds
Understanding the Farming System 234

On-station Testing 237

On-farm Testing 239

Two Agroforestry Interventions for Livestock 243

Producers

Key Sociological Issues 251

Weaknesses and Problems of FSR 252

Future Research Needs 254

Conclusion 256
xii Contents
14. OVERCOMING PROBLEMS OF FODDER QUALITY 259
IN AGROFORESTRY SYSTEMS
R.J. Jones and J.B. Lowry

Characteristics of Fodder Trees and Understory
259
Vegetation and Assessment of Their Feed Quality
Mixing Species to Offset Nutritional Limitations 265
of Individual Species

Overcoming Some Limitations of Fodder
267
by Mineral Supplementation
Detoxifying Problem Compounds and Increasing 269
Digestibility with Bacteria
LIST OF ACRONYMS
277
AUTHORS CITED INDEX
279
SUBJECT INDEX
285
Contributing Authors

AVERY, MARTHA E., Environmental Research Division, Argonne National
Laboratory, 9700 South Cass Avenue, Argonne, Illinois, 60439.
BRISCOE, C.B., Winrock International, 1611 N. Kent Street, Suite 600,
Arlington, Virginia, 22209.
CANNELL, MELVIN G.R., Institute of Terrestrial Ecology, Bush Estate,
Penicuik, Midlothian EH26 OQB, Scotland.
CHUN'TANAPARB, LERT, Faculty of Forestry, Kasetsart University, Bangkok,
Thailand.
HOCKING, DRAKE, Swiss Development Cooperation/Nepal, P.O. Box 113,
Kathmandu, Nepal.
HORSLEY, STEPHEN B., USDA Forest Service, Northeastern Forest Experi­
ment Station, P.O. Box 928, Warren, Pennsylvania, 16365.
JONES, RAYMOND J., Division of Tropical Crops and Pastures, Davies
Laboratory, CSIRO, Private Mail Bag, Post Office, Aitkenvale,
Townsville, Queensland, 4814 Australia.
LOWRY, J. BRIAN, Division of Tropical Animal Production, Davies Labora­
tory, CSIRO Private Mail Bag, Post Office, Aitkenvale, Townsville,
Queensland, 4814 Australia.
MACDICKEN, KENNETH G., Winrock International F/FRED, P.O. Box 1038,
Kasetsart Post Office, Bangkok 10903, Thailand.
MEAD, ROGER, Department of Applied Statistics, The University of Read­
ing, Whiteknights, P.O. Box 217, Reading, RG6 2AN, U.K.
MILLER, I.M., Department of Botany, University of Glasgow, Glasgow,
G 12 8QQ, Scotland.
NARAYANAN, R., Department of Microbiology, Tamil Nadu Agricultural
University, Coimbatore 641 003, India.
ONG, CHIN K., Resource Management Program, ICRISAT, Patancheru
P.O., Andhra Pradesh 502 324, India.
PURUSHOTHAMAN, D., Department of Microbiology, Tamil Nadu Agri­
cultural University, Coimbatore 641 003, India.
REYNOLDS, L., International Livestock Centre for Africa, c/o IITA, PMB
5320, lbadan, Nigeria.