S US T A I N AB L E D E V E LO P ME N T
Sustainable Agriculture:
What Is It? How Do We Achieve It?
Pierre Crosson and Jock R. Anderson
A U G US T 2 0 0 2 · I S S U E B R I EF 0 2 – 2 2
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Issue Briefs are shor t repor ts designed to provide topical, timely
information and analysis to a broad nontechnical audie n ce .
Introduction
There are many different def initions of sustainable agriculture, but there is no point in arguing
about them; they aren’t r ight or wrong, only more or less useful. We find the following to be a useful def inition of sustainable agriculture: an agricultural production system that indefinitely meets
demand for food and fiber while incurring farm-level economic and env iron me ntal costs that societies find acceptable, and that also meets some broad s ocially agreed equity criterion. The definition immediately poses two questions: what are “acceptable” economic and environmental
costs and what is a satisfactor y equity criterion? Clearly, the questions have no precise answers.
What constit utes acceptable costs and a generally sati sfactory equity criterion is, to some ext ent,
in the eye of the beholder. We assume if combined economic and env ironmental costs do not rise
over time, then that is socially acceptable.
A generally acceptable equity criterion is more difficult to specify. The crit erion adopted here
for agriculturally based communities is that, over time, the incomes of poor farm families must
rise enough to permit significant improvements in nutrition for all members of the family and in
access to health and educational services.
The focus here is on the sustainability issue at the farm level. This focus is limited, since it
excludes sustainability issues that might arise in the food distribution system, i.e., that part of the
agricultural system between the farm gate and the ultimate food consumer. But consideration of
distr ibution is sues would take us far beyond the limits of the space available here.
The Global and Less Developed Country Demand for Food
A 1999 study by Pinstrup-Andersen and Cohen and published by the Inte rn ational Food Policy
Research Instit ute (IFPRI) indicates that between 2000 and 2020, about 90% of the increase in
global demand for food is expected to be in the less developed countries (LDCs) of Asia, Africa,
and Latin America. This expectation is based on the facts that the LDCs will host almost all of
the wor ld’s increase in population during that period and the average per capita income in t hose
countries is so low that, when it increases, some portion of the increase will be spent on food. In
contrast, per capita inc ome in the more developed countries is high enough that most people are
so well fed that increases in income add almost nothing to demand for food as registered at the
farm gate. For these reasons, most of the problems of achieving a sustainable agricultural production system almost surely will arise in the developing countries. Accordingly, the discussion
here is focused on those countries.
The Issue so Far
Trends in real food prices
Data compiled by the World Bank indicate that global inflation-adjusted prices of wheat, rice,
and maize (which jointly account for well over half of the calories consumed by people in the
LDCs) declined by 47%, 50%, and 56%, respectively, between 1960/62 and 1995. Prices of each
crop rose from 1995 to 1996 because of world-wide weather-induced dec lines in production. The
weather then improved and, by 1998, prices of all three crops were well below their 1960/62 levels. These price declines reflected increases in global and LDC productivity generated by ad-
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vances in technology adopted by farmers all around the world. In the LDCs, these technologies
are co nsidered part of a Green Revolution (GR) in production of rice, wheat, and maize. The GR
technologies were based on genetically improved varieties of the three crops combined with increased per hectare use of fer tilizers and the provision of irrigation water. The technologies were
widely ado pted across Asia and Latin America. They were not as well adapted to most production conditions in Sub-Saharan Africa; consequently they were little adopted there, much to the
detriment of African agriculture, as will be demonstrated below.
The dec lines in prices of rice, wheat, and maize have two important implications for the sustainability issue:
(1) in the world as it has existed since the end of World War II, long-term declines in agricultural prices reflect dec lin es in the eco nomic costs of pr oduction. Thus, the price dec lines rec orded
here indicate that, over that period, g lobal and LDC agriculture met any reasonable sustainability criterion for the economic costs of productio n.
(2) Because poor people spend propor tionally more on food than non-poor people, the decline
in food prices benefited poor people propor tionally more than the non-poor. The decline in prices,
therefore, tends to suppor t the argument that, in the LDCs, the GR technologies pr omoted more
equity in the distribution of inc ome between the poor and the non-poor.
Trends in nutrition
Other ev idence suppor ts the argument that the GR technologies were consist ent with the equity
criterion for sustainability adopted here, but only in Asia and Latin America, not in Africa. Data
collected by the U.N. Food and Agriculture Orga nization (FAO) show significant improvements
in nutrition among the populations of Asia and Latin America but not Africa from 1969/71 to
1988/1990. The FAO defines ma lnourished people as those w hose average annual food energy
consumption is insufficient to maintain body we ight and support light activity. By this definition,
the FAO found that, over the above time period, the percentage of malnourished people in the
LDCs as a group fell from 36% to 20%, and that the number of malnourished people declined from
940 million to 780 mi llion. The improvement, however, was confined to Asia and Latin America.
In Sub-S aharan Africa, the nutritional status of the people deteriorated, with the percentage of
the malnourished rising from 35 to 37 and the absolute number from 94 million to 175 million.
In today’s world, the primary reason people are malnourished is that they do not have enough
income to buy the food they need. (In Africa, especially, political instability and prolonged and
widespread violence also are part of the problem.) The substantial improvement in nutrition in
Asia and Latin America from the late 1960s to the late 1980s implies that the income of the poor
in those regions increased substantially in that period, providing evidence that agriculture in Asia
and Latin America moved significantly t oward meeting the equity criterion of sustai n ab il ity
adopted here. The decline in the nutritional status of people across much of Africa implies the
contrary, and is strong evidence that, in Africa, agriculture has not met the equity criterion for
sustainability.
Other evidence relevant to equity
Studies specifically aimed at investigating the income and employment consequences of the GR
tech nologies point in the same direction with respect to Asia. In a study at IFPRI (published in
1991), Hazell and Ramasamy examined these consequences a mong farmers and linked commu-
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nities in southern India. They found that both small-scale rice farmers who adopted the new technology and landless farm laborers almost doubled their income. The income of the landless workers rose because the more intensive and productive technology st imulated an increase in the demand for their ser vice s.
In a 1994 study spon so red by the Inte rn ational Rice Research Instit ute in the Ph il i pp i nes,
David and Otsuka reported the results of an in-depth in vestigation of the inc ome distr ibution consequences of GR rice technologies in Thailand, Indonesia, the Philippines, Bangladesh, In d ia ,
China, and Nepal. Adoption was not strongly influenced by farm size or land tenure. Only in China
did farmers with relati vely much land adopt the technologies more rapidly than farmers with relati vely little land. Adopting farmers in all countries achieved higher yields (crop output per unit
of land), hence increases in income.
This review of experience during the past four or five decades indicates that, in most of the
developing countries of Asia and Latin America, the pattern of agricultural development, at least
at the national level, has clearly met any reasonable economic cost criterion of sustai n ab il ity.
Moreover, in t hose countries significant, though still far from complete, progress was made toward meeting the equity criterion adopted here. African agriculture, how ever, has lagged behind
the other two regions, and almost surely is not on a sustainable pat h.
Trends in environmental costs
The env ironmental costs of agriculture are costs imposed by farmers on others in the society under institutional conditions such that those bearing the costs have no way of exacting compensation from the farmers responsible. The main such costs, not necessarily in order of importance,
are those that arise from the clearing and draining of land that harm plant and animal wildlife
habitat and, more broadly, impose losses of socially valuable biological diversity; damages to surface water quality from sediment eroded from farmers’ fields, which increase the cost of cleaning the water for residential and other uses; the cost of dredging sediment from rivers and harbors
to maintain shipping s ervices; the costs of lost recreational values because of muddy water; and
the public health costs and costs of damage to ecological systems because of nitrogen fertilizers,
animal wastes, and pesticides in ground and surface waters. F inally, the economic costs of declining soil productivity (due to land degradation) are often treated as environmental costs. However, where farm ers have secure, enforceable property rights in the land, these degradation costs
are not true environmental costs because the farmers incur, and bear, them through the way they
manage their land. Wh ere the proper ty r ig hts co ndition is not me t—and it may not be in many of
the LDCs—then dam ages to on-farm productivity from land degradation can be regarded as tr ue
environmental costs. In any case, in much of the literature dealing with sustainable agriculture,
these costs are treated as environmental costs, and we so treat them here.
Environ me ntal costs are particularly hard to measure, whether in more developed countries
(MDCs) or LDCs, because the transactions t hrough which the costs are incurred are not registered
in markets. Consequently, costs are not expressed in prices. For example, when farmers drain wetlands to plant a crop, they may destroy wildlife habitat on which hunters, bird watchers, and others who just like wildlife pl ace a high value. This loss of value is a real social cost, but it is not
priced because there is no market for the wildlife habitat services. Consequently, farm ers have
no incentive to take these values into account when deciding whether or not to drain the wetland
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and, correspondingly, those who value habitat services have no way of extracting compensation
from the farmers responsible for their loss.
In the LDCs, there is much concern about the environmental costs of agricultural pr oductio n,
especially from the loss of biological di versity resulting from clearing of land in tropical forests.
The clogging of irrigation canals and rese rv o i rs by soil eroded from farm ers’ fields is also widely
seen as a threat to the capacity of those systems. Despite these concerns, there are no reliable,
global-scale estimates of these costs, nor of others imposed by agriculture, such as the public
health and ecological costs of pesticides and fer tilizers in ground and surface wat ers. T his lack
of well-grounded information means that, with respect to these particular env ironmental issues,
we have no basis for judging whether production with the GR technologies has or has not met the
environmental cost criterion of sustainability. We point out here, however, that the cost criterion
of sustainability adopted here is that, over time, the combination of economic and environmental
costs should not rise. Although we cannot judge the movement of environmental costs, the decline in economic costs, noted above, indicates that an offsetting rise in environ me ntal costs
would be consist ent with sustainability.
Although we do not have enough information to make a judgment about changes in total environmental costs, there are data that permit tentative judgments about the effects of land degradation on agricultural production capacity. One data set permits such estimates on a global scale.
Another set deals with the production impacts of rice grown in Asia using GR technologies.
Global-scale estimates
A global-scale st udy of agricultural land degradation was done by Roel Oldeman and colleagues
at the Wageningen Un iv e rsity in the Netherlands. They found that there are some 8.7 billion
hectares of land in crops, permanent pasture, forests, and woodlands. The study showed that about
2 billion hectares of this land (23%) has been degraded to some extent (slightly, moderately, and
strongly) in the period since the end of World War II to 1990. Eighty-four percent of this land had
been degr aded by wind and water erosion.
Oldeman and colleagues did not estimate the cumulative, degradation-imposed productivity
loss in each of the three degr adation categories. In a 1995 study, Crosson did this by combining
the data compiled at Wageningen with data from another global-scale study done by Harold
Dregne and Nan-Ting Chou at Texas Tech University. Using these two data sets, Crosson calculated the weighted average cumulative loss on the 8.7 billion hectares of land in crops, permanent
pasture, and forest and woodland to be 4.6% (0.1% annually over the 45 years to 1990).
This estimate of global-scale, land degradation-imposed losses of agricultural productivity is
much lower than others found in the literature (for example, by Lester Brown at the World Watch
Instit ute, and David Pimentel and ass ociates at Cornell University). Oldeman and colleagues emphasize the weaknesses in their data. But they (and Dregne and Chou) are exper ts in the study of
soils and the effects of degradation on their productivity. Brown and Pimentel are not such exper ts. We believe the f indings of Oldeman and associates (and Dregne and Chou) are the most reliable, and that they indicate that, on a global scale, cumulative degradation-imposed losses of
land productivity are small. This, in turn, suggests that the GR technologies ado pted by farmers
around the world since the end of World War II have not significantly dam aged the capacity of
the land to suppor t global agricultural productio n.
Sustainable Agriculture: What Is It? How Do We Achieve It?
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Although land degradation damages may have been small on a global scale, they appear to
have been s igni ficant on much rice production land in Asia. A 1998 stud y by Prabhu P inga li
and Mark Rosegrant concluded that intensive cropping of rice in South and Southeast Asia, and
of rice and wheat in a rotation in South Asia, have significantly impaired the pr oductivity of the
land. This has occurred because the pr oduction systems employed have resulted in a salt build-up
and water-logging of the soil, declining soil nutrient status, increased soil toxicities, and increased
pest build-up, especia lly of soil pests. P ingali and Rosegrant note that in the decade from the mid1980s, rice yield growth in those areas was about half of what it had been in the preceding couple of decades. They attribute a substantial part of this dec line in yield growth to the problems
induced by the intensive rice production practices. However, in this part of their discussion, Pingali and Rosegrant make the important point that practices in intensive production in rice and
ric e/wheat rotations are not themselves the root cause of the resulting degradation in land quality and problems of pest control. The difficulties arose from faulty policies that sent the wrong
signals to farmers about how to best manage their land, and from lack of farmer knowledge with
respect to sup erior management practices. It follows that the solution to the land degradation a nd
pest problems in GR rice and rice/wheat production is improved policymaking and investments
in the education of farmers.
Conclusion about the sustainability of the GR production system
The declining trends in prices for wheat, rice, and maize over the past 50 years, despite substantial increases in global demand for these commodities, strongly suggest that the GR technologies
have met the economic cost criterion for sustainability. Big improvements in nutrition in Asia
and Latin America, and studies of the favorable income-distr ibution consequences of the technologies, suggest that, in those two developing areas, the technologies also have moved strongly
toward meeting the equity crit er ion. T his can no t be said, however, for Afric a.
With respect to environmental costs, the evidence indicates that land degradation has not seriously t hreat ened the production capacity of agricultural land, although, in rice and rice/wheat
production in much of Asia, the GR technologies have caused significant land degradation and
the emergence of pest problems. These degradation and pest problems, however, have not been of
such magnitude as to of fset the declining trend in rice prices. With respect to other types of environ me ntal costs, for example, losses of biological diversity because of tropical deforestation
and clogging of irrigation canals and rese rv o i rs with silt, the available evidence is inadequate to
support a conclusion one way or the other. We have to say that we cannot be sure whether the GR
technologies have met the environmental cost criterion of sustainability or not. We can be more
conf ident that in areas such as those in Africa that have thus far not benefited from GR technologies, sustainability is surely in s evere question.
A Brief Look at the Future
The 1999 IFPRI study by Pinstrup-Andersen and Cohen, mentioned above, showed that, in the
period from 1993 to 2020, almost all of the future increases in global demand for food will be in
the LDCs. There is a broad consensus among students of the world food situation that most of the
increased food demand in the LDCs will be met by production in those countries. The consensus
also includes the belief that most of the production increase will have to be through increased crop
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and animal yields. The belief is based on evidence that both the economic and environmental costs
of production would rise to unsustainable levels if the main pattern of production gr owth were toward bringing more land into production rather than toward increasing yields.
This p e rs pective on the future of sustainable agriculture in the LDCs suggests that the key
question about that future is whether agricultural research—in the LDCs themselves, in the system of inte rn ational agricultural research institutions, and in some of the MDCs, particularly the
United States—can succeed in developing the higher-yield technologies necessary to do the job.
But t his perspective poses another question: why do we assume that the task rests on research?
What about gover nment policies and other factors, such as market access that affect farmers’ incentives to adopt the new technologies, even assuming they become available?
Our answer that research is the key rests on what we’ve seen in the past 40 years when, whatever the policy and other limitations affecting farmers’ inc entives, in Asia and Latin America
they ado pted the GR technologies on a wide geographic scale. But we note again that Africa did
not share in this favorable exp erience. One reason was that the climatic, water resource, and soil
conditions across much of that continent were not as favorable as in Asia and Latin America to
the kinds of technologies making up the GR. A nother reason for the failure of the GR to take ho ld
in Africa was unfavorable government policies, including the failure to invest sufficiently in transport and communication systems that would better link farmers to markets, not only in Africa but
to the rest of the world. We can hope, but we cannot as sume, that those unfavorable policy conditions will be overcome in Africa’s future. The focus here, then, is on prospects that agricultural
research will successfully develop the yi eld-increasing technologies that the LDCs will need over
the next several decades if they are to achieve a sustainable production re sponse to future demands
for food. There is gr owing con ce rn that the research ente rp rise may fall shor t. A 1997 article in
Science ma ga zi ne put it this way: “The [global] surge in demand [for food] will occur even as evidence suggests that the Green Revolution is petering out. In recent years grain yields have stopped
rising so fast, and plant scientists agree that they are facing physical limits as they try to coax
plants to produce ever more of their weight in grain.” The data do, indeed, show that percentage
increases in rice and wheat yields were s ignificantly less from the mid-1980s to the late 1990s
compared to the increases obtained from the mid-1970s to the late 1990s. (Percentage increases
of yields of coarse grains—mainly maize—were unchanged, however.)
But perhaps it is time to question the practice of stating average annual rates of yield growth
as percentages when making judgments about the adequacy of future yield gr owth. The reason is
that the United Nations’ projections of population gr owth in the LDCs over the next few decades
show continuously declining percentage rates of increase. Add to this the prospect that, as per
capita income in the LDCs continues to grow, more and more of them will reach income levels
that are high enough that additional income will add little to food demand registered at the farm
gate. The combined impact of s lowing percentage population growth in the LDCs and diminishing impacts of per capita income growth on the demand for food in those countries suggests that
declining percentage increases in crop yields may not be as serious a threat to future food supplies
as many now seem to think.
This leads us to take a look at what has been happening to the arithmetic rate of increase in
grain yields. Data provided by the U.S. Depar tment of Agriculture s hows in the 11 years from
1988 through 1998 there was no slackening in the arithmetic rate of increase in rice, wheat, and
maize yields in the LDCs. If this pe rf o rmance can be ma intained over the n ex t few decades, then
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yield gr owth for the t hree principal grains may in fact be enough to meet future demands for food
in the LDCs. But there is reason to question whether even the arithmetic rate of yield increase
can be mainta ined. The questioning arises from two aspects of recent trends in investments in
agricultural research on a global scale. One aspect concerns the quantity of such research. The
other co ncerns the direction of the research.
Will the quantity of research investments be enough?
In 1998 Alston, Pardey and Roseboom published an article in World Development in which th ey
showed that, from 1971 to 1981, global in vestments in agricultural research increased at an average annual rate of 6.4%. Between 1981 and 1991, the rate declined to 3.8%. In Africa, a region
especially in need of new agricultural knowledge, the rate declined from a low 2.5% to an even
lower 0.8%, and in Latin Am erica agric ultural research spending actually declined. If these tr ends
continue, as seems to be the case, invest me nts in agricultural research over the nex t c ouple of
decades may not be enough to sustain adequate yield growth. In this case, the economic costs of
food production around the world might rise enough to violate the economic cost criterion of sustainability.
We must say a word here about research to develop genetically modified organisms (GMOs).
These technologies do not necessarily increase yields. Those developed so far in the U.S. for co rn ,
soybeans and cotton are yield-neutral but they are attractive to farmers because they reduce costs
of using pestic ides. But research already is underway to develop GMOs which also increase yields,
for example by building drought resistance into the crops’ genetic structure or making genetic
changes that increase the efficiency of p hotosynthesis. So GMO research has high potential for
developing new yield-increasing varieties of the principal crops. Nevertheless, the future of GMOs
is problematical. The reason is that environmentalists, e specially in west ern Europe, have raised
questions about the environ me ntal and human health consequences of widespread planting of
GMO crops. The result is that in that part of the world, GMO based crops are either banned or
market access to them is severely constra ined. Similar concerns have been expressed in other parts
of the world. Needless to say, if farmers cannot sell GMO based crops, they will not pr oduce them.
It is not c lear that the high potential of these crops will be realized.
What about the direction of agricultural research?
Here, the direction of research refers to the amounts of research invest me nts directed at technologies that would keep economic costs within acceptable levels, relative to the amounts a imed
at containing environmental costs. Evidence suggests that (1) the demand for environmental services in the LDCs will increase faster than the demand for food over the nex t couple of dec ades,
and that (2) it may prove more difficult to adequately increase the supply of environmental services than the supply of food. The implication is that it may well prove easier to meet the economic cost criterion for sustainability in the LDCs than to meet the environmental cost criterion.
The evidence suggesting that the demand for environmental services in the LDCs may increase
faster than the demand for food comes from the experience of the more developed countries—for
example, the United States, Canada, and Western Europe. The high inc ome in these countries has
induced a much faster increase in demand for environmental services than for food during the past
several decades. There already is some evidence of a similar experience in the higher income LDCs
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and, as per capita inc ome cont inues to increase in the LDCs, it is reasonable to expect a comparable effect across these countries as a group.
This pro spect suggests that, if the environmental cost criterion is to be met with respect to
agriculture in these countries, research must be undertaken that will increase the supply of environmental services in step with the relati vely fast-rising demand for the s ervices. T his may prove
difficult to do. Most simply put, increasing the supply of environmental services requires institutional innovation. For example, institutions for the management of water resources must be devised that give proper weight both to the use of the water for irrigation and to its use to protect
aquatic wildlife and for recreation. Experience in the United States demonstrates that constructing such institutions is fr aught with difficulties, most having to do with conflicts of interests between farmers and env ironmenta lists.
There is reason to doubt whether agricultural research institutions around the world are well
positioned to do the kind of institutional research needed to adequat ely increase the supply of environmental services. By long tradition, those institutions have devoted themselves to developing new techn ol o g ies that would contain the on-farm economic costs of production. They are
staffed mostly by sci entists who have demonstrated they are very good at developing such technologies. It is very unlikely they would be equally good at devising the institutional innovations
that will be needed to adequately increase the supply of environmental services. Achieving that
goal will probably require a major restructuring of the present agricultural research institutions.
In some work the authors did nine years ago for ISNAR (an institute in The Hague con ce rned with
developing natio nal agric ultural research capacity), the considerable institutional challenges facing agricultural research in the LDCs were charted; advances in meeting those challenges since
then have not been particularly encouraging. Whether the LDCs will succeed in meeting the future env ironmental cost criterion for agricultural sustainability, regrettably, remains in doubt.
Pierre Crosson is a RFF senior fellow; J ock R. Anderson is an adviser with the World Bank’s Rural Development
Depar t me nt.
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