Adapted and excerpted from "Environmental considerations in expanding agricultural production," by Pierre R. Crosson in the Journal of Soil and Water Conservation, January-February 1975.
The major policy issue confronting American agriculture has long been that of dealing with chronic excess capacity. Events of the last couple of years suggest that the principal issue for the indefinite future may be just the reverse: how to deal with chronic scarcity. Many interpret these events as signaling the emergence of a period in which world food supply will be under constant heavy pressure to keep up with demand—with the outcome always in doubt.
It is too soon to know whether this interpretation is correct. If the world economy, particularly that portion of it in the less developed countries (LDCs), continues to expand, there is little doubt that demand for food, particularly for protein and protein sources, such as feed grains and soybeans, will also grow. Whether this implies chronic scarcity will depend a great deal on how successfully the LDCs expand their food supplies.
If they can accelerate the increase in production, pressure on world food supplies will be much less. But unless they do significantly better than over the last 25 years, the probability of scarcity will be high. Under these circumstances, foreign demand for U.S. agricultural products will continue to rise, and the possibility of greatly increased pressures on the environment emerges.
The environmental impact of increasing agricultural production in the United States will depend upon the magnitude of the increase and the technology employed to bring it about. In each case the range of possibilities is so wide that well-grounded statements about likely outcomes are difficult.
This is reflected in recent export projections by the U.S. Department of Agriculture. One projection assumes that the high exports of 1972-73 and 1973-74 were exceptional and that by 1985 sales abroad of wheat, coarse grains, and soybeans will be on the order of 77 million metric tons, some 10 percent less than in 1973-74. The other projection assumes much more vigorous growth, with exports of the three commodities rising to almost 120 million tons by 1985, almost 40 percent above the 1973-74 level (1).
These projections reflect different assumptions about the growth of production and consumption among America's major trading partners, but the greater part of the difference is attributable to the less developed countries of Africa, Latin America, and Asia (excluding China and Japan). These countries will push hard to increase per capita food consumption and to improve the quality of their diets, particularly in protein. If they succeed, then, given their high rates of population growth, demand for grains and soybeans could easily grow by 3.5 to 4.0 percent annually over the balance of this century. Assuming a 3.7 percent growth in demand, grain consumption in the less developed countries (LDCs) would amount to 890 million tons in the year 2000.
The consequences for U.S. exports would depend in large measure upon the ability of these countries to increase production. Over the last couple of decades they managed an average increase of slightly more than 3.0 percent annually. If this trend persists to the end of the century, grain production at that time would be 735 million tons, leaving a gap of 155 million tons to be filled by imports. Since total LDC grain imports in 1973 were about 23 million tons, the implied growth in import demand by these countries is 132 million tons, a six-fold increase over the 1973 level. Much of this probably would have to come from the U.S., indicating an enormous increase in our grain exports to the LDCs. Soybean exports also would increase dramatically.
Should the LDCs achieve a faster rate of growth in grain and soybean production, the demand for U.S. exports would be less. If, for example, LDC grain production were to keep pace with the assumed 3.7 percent annual increase in demand, then the production-consumption gap for grains in the year 2000 would be 85 million tons.
Despite these various qualifications, the projections make the point that, aside from year-to-year fluctuations, the demand for U.S. food exports could expand significantly over the balance of this century. And under some circumstances the rise could be very steep indeed. Any increase in export demand, when added to the foreseeable rise in the domestic market, will increase the pressure on the nation's environment.
For any given amount of agricultural production the degree and kind of environmental pressure will depend upon the kind of technology adopted. Technological alternatives can be thought of as either land-using or land-conserving.
Land-using Technologies
The environmental problems with land-using technologies are primarily those associated with wind and water erosion and loss of habitat (for example, drainage of wetlands).
While the loss of habitat may be critically important in local situations, the more general problem associated with land-using technologies is erosion by wind and water. In terms of soil moved, water erosion is considerably more important than wind erosion. A commonly cited estimate is that 4 billion tons of soil are moved annually by water in the United States, while wind erosion accounts for as much as 30 million tons (2). Not all of this is lost to agriculture, of course. Some soil transported by water is deposited in floodplains where it is available for agricultural uses, but a substantial proportion is washed into the oceans or otherwise removed from the farmer's reach. This soil loss is an important part of the environmental cost of erosion.
The other principal cost is the damage done to the nation's rivers, lakes and reservoirs. Turbidity lowers the recreational values of these waters, and sedimentation reduces the capacity of stream channels and reservoirs. Erosion also is the principal means by which phosphate fertilizer is transported from fields to streams, lakes and reservoirs where it feeds unwanted growth of aquatic plants.
The United States has made considerable progress in the control of erosion over the last several decades. This resulted from the conversion to non-crop uses of much land susceptible to erosion and the adoption of such conservation practices as mulching, strip-cropping, terracing, and contour cultivation. While erosion losses continue, indicating room for further improvement, it is fair to say that under conditions prevailing in the United States in the early 1970s, erosion was not a major environmental hazard (3).
Land-conserving Technologies
The environmental problems associated with land-conserving technologies are those resulting from the use of fertilizers and pesticides and, in the case of irrigation, from the build-up of soil and water salinity. Fertilizers of special interest are nitrogen and phosphorus. In each case the principal concern is that some nutrients applied to find their way into water bodies, including groundwater, where they may have damaging effects.
Nitrogen in the form of nitrate may percolate into aquifers where it constitutes a health hazard, particularly to infants, if the aquifer is tapped for drinking water. The number of people demonstrably damaged by nitrate is small, suggesting that the threat is not a major one. Greatly increased use of nitrogen fertilizer, however, may modify this judgment (3).
The more common problem is the effect of nitrogen and phosphate residuals that enter water bodies where they stimulate the growth of aquatic plants, thus increasing the burden on the water's supply of dissolved oxygen. Carried far enough, this process will make the water unusable for recreation and spoil its capacity to support fish life. The potential damage from increasing the quantity of nitrogen or phosphorus in water is clear. It is not clear, however, whether present levels of use of these nutrients as fertilizer presents a serious environmental hazard in the United States.
Concern with pesticides in the environment has centered on unintended damage to plant and animal life, to human health, and even potential harm to the genetic stock of the race. This concern is not unfounded. There are well-known cases of pesticide poisoning of humans; of unintended elimination of natural insect predators; of accumulation through the food chain of persistent pesticides, particularly in fish and birds, with resulting damage to reproductive processes.
Initially, public attention focused most closely on persistent pesticides, particularly DDT, the use of which has now been banned in the United States. Recently, the Environmental Protection Agency suspended use of aldrin and dieldrin, also persistent pesticides, on the ground that they may cause cancer in humans.
Total pesticide use has risen rapidly over the last decade, mostly, but not entirely, in agriculture. Parathion and other organophosphorus compounds have substituted for DDT and other chlorinated hydrocarbons as insect controls (2). In addition, application of organophosphorus herbicides has increased rapidly over the last decade. The net result has been not only a substantial growth in total pesticide use but a decided shift toward the non-persistent organophosphorus compounds and a relative decline in the persistent chlorinated hydrocarbons. We have thus exchanged one set of environmental hazards for another since the toxicity to mammals of some organophosphorus compounds, especially the parathions, is often higher than that of the chlorinated hydrocarbons (3).
It is probably fair to say that as a result of this shift the major present threat to man in the use of pesticides is the danger of accidental poisoning during the application (2). This is a danger comparable to industrial accidents. Long-term hazards resulting from the build-up of persistent pesticides in the environment now look less menacing than they did a few years ago when the use of these pesticides was expanding rapidly. On balance it may be concluded that while pesticides have not convincingly been proved responsible for disastrous and permanent environmental damage, we must use them with great caution, at least until we have greater knowledge of how they impact upon the environment (3).
Irrigation is a land-conserving technology since it increases the productivity of the land by increasing the quantity of a major non-land input—water —per unit of land. Irrigation water always contains some salts that are left on the land when the water is removed. Over time the build-up of these salts can seriously inhibit the ability of plants to absorb water and nutrients, thus impeding growth.
To maintain soil productivity the salts brought to the land by irrigation water must be removed by leaching with drainage water. But since the quantity of drainage water is less than the amount of irrigation water applied, the salt content of the drainage water is greater. Its return to the river, therefore, increases the salt content of water available to downstream users. The plight of Mexican farmers in the lower reaches of the Colorado River is only one of the most notorious cases of this common phenomenon.
Growth of exports at the high rate discussed earlier would require a mobilization of agricultural resources on a scale not previously experienced in the United States. The possibility of significantly higher environmental damage would then require serious attention. The key problem from the standpoint of the national welfare is to find the most economical mix of land-using and land-conserving technologies, taking into account not only the costs of resources to the farmer but also those environmental costs not borne by the farmer himself but by his neighbors and society generally. A major difficulty in achieving a desired expansion path of this sort is precisely that the farmer typically does not bear the full environmental costs of his activities. If he did, then the operation of normal market forces could be counted on to guide agriculture along the socially preferred route. Instead, government must find some way of asserting the public interest in protecting against environmental damage.
Detailed prescriptions of possible courses of action must await more information about the likely growth in foreign demand and the cost, including environmental cost, of alternative responses to it. However, at least over the medium term, a response that weighs land-using technologies more heavily than land-conserving technologies may be most desirable. This is because we have much more knowledge of the environmental costs of the former than of the latter—and we already have a well-developed institutional structure, the Soil Conservation Service and the system of soil conservation districts, for dealing with erosion.
The Challenges Ahead
American agriculture has a large stake in the outcome of the race of less developed countries to meet their growing demand for food. If the LDCs succeed in meeting most of their own requirements, then the combination of foreign and domestic demands for US food production could be accommodated with little increase in economic costs and manageable environmental impacts. If the LDCs fail to keep pace with rising demand, the pressure on our resources could be severe and the threat of environmental damage from erosion, habitat loss, salinity build-up, and fertilizer and pesticide use greatly magnified.
The high-growth situation would present us with some difficult choices in dealing with these environmental threats. Basically these choices concern the most appropriate technological response to the increase in demand. There are a couple of other alternatives that ought to be mentioned, however. One would be to prohibit a full response by imposing export controls; for example quotas or export taxes. Such measures might be appropriate from time to time to deal with unexpected short-term developments threatening severe shortages and sharply higher prices in domestic markets. As a settled policy for the long term, however, they appear unattractive. Enforcement of quota system would require additional bureaucratic machinery, which itself could be costly. It would also encourage evasion and corruption. Moreover, any kind of export curbs would run against the deep-rooted U.S commitment to the principle of freer trade and encourage retaliatory action by other countries. More generally, the image of a niggardly, inward-looking America could weaken our hand in dealing with other foreign policy issues.
Another alternative would be to reduce pressure on domestic production by encouraging faster growth of food production in the LDCs. There is not space here to develop this theme, but it should be prominent in our thinking about U.S. agricultural policy. The assumption underlying this alternative is that the principal future problems in U.S. agriculture will concern management of scarcity, not surplus as in the past. If scarcity reigns, then encouragement of foreign production would be clearly in the interest of American consumers and consistent with the maintenance of a prosperous domestic agriculture. Domestic environmental pressures would be less, and the United States probably would benefit from greater political stability in the LDCs.
We have considerable experience in helping development of LDC agriculture. The technology and spread of the Green Revolution are primarily the result of American initiative and resources. The process of agricultural modernization still has far to go in the LDCs and faces formidable obstacles. Nevertheless, encouragement of it may prove a valuable part of the total U.S. response to rising foreign demand, permitting production to grow in a way consistent with both a healthy agriculture and a healthy environment.
References Cited
- Rojko, Anthony S. 1973. Future prospects for agricultural exports. Proc., Midwest Agr. Outlook Conf., Purdue Univ., Lafayette, Ind.
- Committee on Agriculture and the Environment. 1973. Productive agriculture and a quality environment. Nat. Res. Council, Washington, D.C.
- Brubaker, Sterling. 1972. To live on earth: Man and his environment in perspective. Johns Hopkins Press, Baltimore, Md.
A version of this article appeared in print in the June 1975 issue of Resources magazine.
