Table Of ContentINTEGRATED RESOURCE
MANAGEMENT
Agroforestry for Development
Edited by
Charles V. Kidd
Directorate for International Programs
American Association for the Advancement of Science
Washington, D.C.
David Pimentel
Department of Entomology
Cornell University
Ithaca, New York
Published in cooperation with the American Association for the Advancement of
Science, Committee on Population, Resources, and the Environment
ACADEMIC PRESS, INC.
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Library of Congress Cataloging-in-Publication Data
Integrated resource management: agroforestry for development /
[edited by] Charles V. Kidd, David Pimentel.
p. cm.
ISBN 0-12-406410-8
1. Agroforestry-Developing countries. 2. Agricultural resources-
-Developing countries-Managment. 3. Food supply-Developing
countries. 4. Developing countries-Population. I. Kidd, Charles
581.2'34~dc20 91-42901
CIP
PRINTED IN THE UNITED STATES OF AMERICA
92 93 94 95 96 97 BB 9 8 7 6 5 4 3 2 1
Contributors
Elise Boulding, Boulder, Colorado 80707
Edwin Clark, Conservation Foundation, Washington, D.C. 20037
Paul Demeny, The Population Council, New York, New York 10017
Louise Fortmann, Orlando, California 94602
Jeffrey Gritzner, Public Policy Research Institute, Department of Geog
raphy, University of Montana, Missoula, Montana 59812
Charles V. Kidd, Directorate for International Programs, American Asso
ciation for the Advancement of Science, Washington, D.C. 20005
Donella Meadows, Resource Policy Center, Thather School of Engineer
ing, Dartmouth College, Hanover, New Hampshire 03755
Peter Oram, IFPRI, 1776 Massachusetts Avenue, NW, Washington, D.C.
20036
David Pimentel, Department of Entomology, Cornell University, Ithaca,
New York 14853
Paul Riley, Utah Water Research Lab, Utah State University, Logan, Utah
84322
Fred Troeh, Department of Agronomy, Iowa State University, Ames, Iowa
50011
Robert Winterbottom, International Institute for Environment and Devel
opment, Washington, D.C. 20036
ix
Foreword
Increases in global agricultural output of food—particularly grains—
have been astonishing over the past few decades. Much of the increase is
attributed to high-energy-input, large-scale agriculture in both developed
and developing countries. The high-energy input is in the form of such
things as machinery, fuel, fertilizer, pesticides, and irrigation. In the devel
oping world this system of agriculture, depending heavily but not entirely
on the widespread adoption of new strains of such grains as rice and
wheat, is widely known as the Green Revolution. As a summary phrase it
encapsulates the set of techniques that has been such a spectacular success
in lifting the output of wheat, corn, and rice in the developing world—
particularly in such countries as India, China, Pakistan, Bangladesh, Thai
land, and Indonesia.
What is not so widely recognized is the fact that the techniques of the
Green Revolution are not applicable to large parts of the developing world
for a number of reasons. These include poor soil, slopes, and other marg
inal lands that preclude the use of large machinery; inadequate or poorly
timed availability of water; farm size averaging less than a hectare; crops
dependent on hand cultivation at all stages; and inadequate income.
Hundreds of millions of people depend on food produced under these
adverse circumstances. There is, therefore, an urgent need for the develop
ment and widespread adoption of alternatives to high-energy-input agri
culture. A central theme of this volume is a demonstration of the need for
such systems, an explanation of different alternative agricultural systems,
and an exploration of the problems and challenges encountered in foster
ing their adoption.
The volume concentrates on one of the central problems facing the
world: how to provide food for the rapidly growing populations of the
developing countries. The specific part of this vast and complex problem
addressed by this volume is how to design, install, and sustain systems of
agriculture appropriate for the large parts of the developing world where
the approach of the Green Revolution is partially or totally unworkable.
These systems are characterized by low use of energy, small-scale, in
tensive use of labor, concern for long-term sustainability, low use of com
mercial fertilizer and insecticides, and often by combining trees and other
xi
xii Foreword
crops. These are the systems to which primary attention is paid in the
volume, with particular attention given to agroforestry—combining trees,
shrubs, and other crops. The central points of emphasis have been stated
in a growing body of literature that is referred to at appropriate points in
the text. These books, articles, and reports vary in such matters as points
of emphasis, disciplinary framework, views on the outlook for the future,
and attention to technical detail. This volume is characterized by emphasis
on the significance of rates of population growth, the importance of cul
tural and political forces, the necessity for elimination of poverty as a goal
transcending increases in agricultural output, and the attendant oppor
tunity for widespread adoption of low-energy-input agricultural systems
complementing systems dependent on high-energy input. It is important
to note that these systems are not a panacea and are not a substitute for the
techniques of high-energy input that has characterized the Green Revolu
tion. They do offer productive, sustainable alternatives for millions of
families who cannot afford the high-energy option, or who live on land
unsuitable for large-scale, high-energy-input agriculture.
The studies underlying the volume were undertaken on the initiative of
the Committee on Population, Resources, and the Environment of the
American Association for the Advancement of Science. The central aim of
this Committee, as indicated by its name, has been to explore the inter
relationships among rates of population growth, stress on the environ
ment, and the adequacy of renewable and nonrenewable resources. The
committee decided that the enormous task of feeding a growing world
population raises issues that can be satisfactorily approached only by
considering these interrelationships in an interdisciplinary manner. To do
this the Committee set up three working groups. They dealt with Food and
Population, Soil and Water, and Agroforestry. The members of the Com
mittee and the Study Groups are listed in Appendix A. Without the gener
ous contributions of time and energy by the Study Group members, this
book would not exist.
Many people contributed to the thinking, research, drafting, review, and
redrafting that produced this book. Some early efforts resulted in drafts
that were good in themselves and responsive to needs felt at the time, but
that did not fit into the final framework of the book. Ideas and facts drawn
from these efforts appear at various points in the final text. In the course
of redrafting, many facts and ideas were moved from their original place,
and, as a result, do not appear as products of their authors. In addition, the
ideas of original authors were modified, expanded, or curtailed in the
process of producing a unified manuscript. Nevertheless, the primary
authors are identifiable, and their contributions are noted in the notes
appearing on the first page of each part.
Foreword xiii
Charles Kidd, with help from David Pimentel, was primarily respon
sible for transforming a large number of disparate segments into an in
tegrated whole. A number of A A AS Staff members, primarily Barry Gold,
Priscilla Reining, and Amy Wilson, participated in the development of the
manuscript. The late Vonna Dennison prepared numerous drafts with
great competence and dedication.
Not every contributor agrees with every fact and judgment in the book,
but the text does reflect their understanding of the basic facts, the state
ment of the major problems, and the proposed approaches to solutions.
The Andrew W. Mellon Foundation and the American Association for
the Advancement of Science funded the activities of the Committee on
Population, Resources, and the Environment and its Study Groups, and
their assistance is gratefully acknowledged.
Roger Levien
Part I
Overview
Chapter 1, Food Production. Compiled by Charles V. Kidd based primarily
on material drawn from drafts of the Parts that follow.
Chapter 2, Population Change: Global Trends and Future Implications.
Written by Paul Demeny, with contributions by Donella Meadows and
Charles Kidd.
Supplemental papers on aspects of population/food relationship were
prepared by a study group on the Interdependency of Population and
Food, consisting of Donella Meadows (Chair), William Hudson, Ralph
McCracken, Peter Rogers, Peter Timmer, and Beverly Winikoff. The papers
include The Global Problem of Nutritional Adequacy (Beverly Winikoff), Food
Supply Adequacy and Food Distribution (William Hudson), and World Food
Production (Ralph McCracken). Ideas and facts drawn from these papers
appear in Parts II and IV, as well as in Part I.
1
Chapter
Food Production
INTRODUCTION
At the beginning of the agricultural age about 10,000 to 12,000 years ago,
when human societies first began to turn from hunting, fishing, and gath
ering to agriculture, the total population of the earth was about 5 to 10
million—somewhere between the population of Bangkok and Bombay.
For thousands of years the total population of the earth increased very
slowly in absolute numbers. By the time of Christ, the total population of
the world had reached a level of about 300 million—slightly more than the
current population of the United States (Douglas, 1966; Harris, 1977). Only
at the time of the beginning of the industrial revolution around 1700 did
world population begin to grow rapidly.
The world population reached 1 billion in 1825. It took a century, until
by 1925, for this population to double. The third billion was reached in
1960—35 years. Then in 15 years—1975—another billion was added.
Then, at one unspecifiable moment in 1987, the baby who made the world
population 5 billion was born somewhere on the planet, probably in Asia,
where nearly 60% of the world's population lives. An annual growth rate
of 1.7% is adding 77 million people per year—a number equal to that of
the population of Mexico—to the number who share the planet's resour
ces. The annual increment to the world's population will continue to
increase for decades, reaching a peak of almost 90 million over the period
from 2000 to 2005. The United Nations projects a population of 7.8 billion
by 2000 and 12 billion by 2100. Of these future population increases, 90%
will occur in the developing countries. In 1950, 66% of the world popula
tion was in developing countries. By 2020, 82% of the world population
will be in these countries. Over the period from 1950 to 2020, the propor
tion of the world population in North America and Europe will drop from
22 to 11%. (These trends are discussed in Chapter 2.) These sharp popula
tion increases threaten the delicately balanced ecosystems of planet earth.
3
4 1. Food Production
They call into question the ability to feed hundreds of millions of addi
tional people without exhausting renewable natural resources.
About 60% of the world's total 1990 population of about 5.2 billion live
in rural areas. In the less-developed countries, 70% of the total population
is in rural areas (Population Reference Bureau, 1989). In Asia and Africa,
about 80% of the population live in rural areas (World Bank, 1984). In Latin
America, about 30% of the population is rural. The vast majority of the
rural populations in developing countries is engaged in or dependent on
agriculture, and a high proportion of the agriculture is low energy, small
scale, and labor intensive. For example,
Low-resource agriculture is the predominant type of agriculture practiced
throughout Africa, and it makes a crucial contribution to food security—
both the availability of food and the ability to buy it. It is the source of most
of Africa's food, a primary income and employment source for the majority
of Africans, a source of foreign exchange, and a buffer against food shortfalls
and famine. [Office of Technology Assessment (OTA), 1988]
As noted in more detail in Chapter 2, the rural population of developing
countries is likely to increase by about 1 billion by the middle of the next
century. These are all rough estimates, but they are sufficiently accurate to
demonstrate that rural populations directly dependent on small-scale,
low-input, subsistence agriculture are substantial proportions of the world
population. Any solution to the problems of feeding the growing world
population must pay specific attention to the needs of this group. Yet
relatively little research has been done on the crops of major importance
to them—millet, sorghum, cassava, yams, maize, and cowpeas. Similarly,
only recently has substantial attention been devoted to the design and
management of agricultural systems to meet their needs.
While the rural population is increasing, the urban population will also
increase, not only in total numbers, but also as a proportion of total
population (World Bank, 1984).
Urban Population (%)
Country or region 1980 2000
India 23 35
East Asia and Pacific 32 42
Sub-Saharan Africa 49 55
Latin America 65 75
The agricultural systems of the world must provide not only for the
needs of the rural population but also for those of the urban dwellers who
produce much less food and other agricultural products than they con-
Unprecedented Increase in Food Production, 1950-1985 5
sume. The nature of this problem varies widely among countries and
regions, as indicated by the fact that in the year 2000,75% of the population
of Latin America but only 35% of the population of India will be urban.
If the increasing numbers of city dwellers are to be fed, either domestic
agriculture must produce increasing surpluses above the needs of the rural
population, or food imports must increase, or a combination of both will
be required.
While low-input, small-scale agriculture systems are now producing
food and other products—especially fuelwood—that are consumed by
urban dwellers, the primary function of those systems is to meet the needs
of rural people. Most of the food and other agricultural products con
sumed by urban dwellers is produced by high-energy-input systems,
either domestic or foreign, in the form of food imports.
UNPRECEDENTED INCREASE IN FOOD PRODUCTION, 1950-1985
An outstanding characteristic of the food/population relationship be
tween 1950 and 1985 was a rapid rise not only in total grain production but
also in per capita production for the world as a whole, thereby confound
ing prophecies of mass starvation. World grain production almost tripled
from 600 million tons in 1950 to 1700 million tons in 1985 (USDA, 1988).
During that same period, the population of the world almost doubled from
2.5 billion to 4.8 billion (UN, 1988). Accordingly, per capita grain produc
tion increased from 480 pounds to 710 pounds per year.
Not only did total yields increase rapidly, but production per hectare
also increased. In 1950 the grain yield was one ton per hectare (2.47 acres)
(USDA, 1988). By 1985 this figure more than doubled to 2.3 tons per
hectare. Irrigation, fertilizer, new high-yielding crop varieties, and educa
tion of farmers were the primary sources of this increase in productivity.
These overall figures mask some wide regional variations, but they convey
correctly the story of an unprecedented growth in food production, out
stripping a similar growth in world population.
Another measure of the adequacy of food supplies is provided by prices.
Rising prices are an indication of scarcity; falling prices indicate decreasing
relative scarcity. In many respects, world grain prices are a better measure
of scarcity than is per capita food production, because international grain
shipments integrate world markets and thereby make per capita output in
individual countries and regions a misleading indicator of food supply.
The World Bank reports, "For decades the real dollar prices for grains in
the world market defined as crop-year average prices deflated by the 1980
U.S. consumer price index have declined" (World Bank, 1988). Both the
