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CHAPTER 8 UNITED STATES CROPLAND: SIZE AND POTENTIAL CROPLAND ACREAGE IN THE UNITED STATES An estimated 360 million acres were used for crops in the 48 contiguous states in 1974, excluding idle cropland and cropland pasture. Including these categories, the total cropland is about 430 million acres, and this is approximately the maximum amount cropped at any time during this century in the United States. Since 1949, some 70 million acres have been dropped from the cropland base, chiefly in areas characterized by broken terrain, small fields and small ownership units. During the same period, from 35 to 40 million acres have been added. According to unpublished data compiled by the ERS, there are currently some 10 million acres of high quality (Class I) land suitable for conversion into regular cultivation (Smith et al., 1974). An additional 250 million acres could be used for cropland, but they are subject to climatic limitations, and to problems related to soil, drainage, and erosion. Less than 100 million acres are considered high in potential for conversion into cropland. The ERS concludes that there is adequate cropland available to fill domestic United States needs and expected foreign demand for several decades. With continued favorable prices for farm products, no constraints on land use, and a reasonable rate of development, land could be converted to cropland as needed to fill our long term food and fiber needs. A degree of food security and an expansion of foreign trade would increase the need for cropland. It does not necessarily follow that increased agricultural crop production will result in more land being cultivated. Part or all of whatever increased needs may develop will undoubtedly be met by more intensive farming of lands already being cropped. In the future we may be concerned primarily with optimum production per unit of land. It may also be that we now have about all the row- crop land we will use, and that much of the land now considered as reserve could better be used for forage and pasture, timber, and recreation. - 93 -
AGRICULTURAL PRODUCTION EFFICIENCY The National Academy of Sciences has recently (1975b) published a report on the productivity and efficiency of United States agriculture. The Report distinguished between the ability of the land to produce a yield of crop, i.e. produetivitv, and the capacity to produce desired results with a minimum expenditure of time, money, energy, or materials, i.e. efficiency. Productivity is subject to biological limitations. First, for every set of soil, water, climate, nutrient, and other conditions there is some upper limit for the yield of every crop and livestock product. We do not know precisely where these upper limits are, but agronomists are thinking optimistically of 300-500 bushels of corn per acre, 300 bushels of small grain, and 200 bushels of soybeans. Second, since these upper limits are defined in terms of relatively ideal conditions, we have what we term a "field gap" between this yield limit and the actual yields obtained under farm situations. Reports from the field claim as high as 300 bushels of corn and 200 bushels of wheat per acre, but averages on even the better farms are only one-half of these reported levels. Much of our newer technology enables us to increase yields gradually and reduce the field gap. Only in rare and doubtful instances, however, has any research finding raised the biological ceiling. One of our tasks has been to examine these biological limitations that impose either temporary or permanent limitations on the productivity of our farms. No major scientific breakthrough comparable with hybrid corn or DDT can be reasonably predicted for the next one or two decades. There remain, however, promising potentials for improving productivity from application of known technology and from new technology now in the research and development phases. Long-range planning based on continued linear upward projections of productivity of all parts of agriculture, though, can be hazardous. The large gains in the past quarter century that came from concentrating production on the more optimum sites for individual crops; planting and pruning for maximum leaf area indexes; elimination of severe weed competition; improvement of defenses against insects, disease, and nematodes; and better farm mechanization will be difficult to duplicate over the next 25 years. However, further improvements in the same areas will continue to enhance productivity for the next decade or so. Also, the genetic variability of plants should permit continued upgrading of gains in yield and quality. - 94 -
On balance, however, biological realities suggest a slowing of the rate of increase of productivity for most crops in the foreseeable future, even though the theoretical yield limits are far ahead. Among livestock, current limitations appear greatest in reproductive efficiency, resistance to disease, adaptability to unfavorable weather, and ability to convert feed energy to animal protein. These are likely to restrict major gains in livestock production efficiency for the near future. Some research-based advances, such as more twinning in cattle, more frequent lamb crops, and larger pig litters should, however, improve animal productivity. Gains in efficiency of milk production and improved carcass yields for livestock should continue. Fowl and egg production technology seems close to the point of leveling off, and breakthroughs are needed before further gains in egg production and feed conversion efficiencies occur. Overall, gains in livestock productivity appear probable through the next decade or two. Integral to the assessment of agricultural production efficiency is elucidation of the relationship between the input of energy and productivity. Handler (1970) and other have criticized the inefficiency of modern agriculture in converting calories of total energy input to calories of output in harvested products. The Agricultural Production Efficiency report (NRC 1975b) responds to this contention with an analysis of the energetics of agricultural production. It summarizes the efficiency of energy use on the farm in the following language: Farming, like other segments of the economy, must seek ways to increase its efficiency of energy use. Since agriculture produces energy-containing products of food and fiber, but consumes free solar energy and substantial quantities of increasingly expensive fossil fuels and electric power, the relationships are complex. Crops capture 1 percent or less of the photosynthetically useful sunlight that reaches earth, and for most crops only half of this capture energy is stored in food products. In the next step in the food chain, farm animals convert 4-10 percent of the energy in feeds into meat food energy. Broilers and hogs are about twice as efficient as cattle in converting feed energy to meat food energy. In the transition from primitive to modern agriculture, fuel energy has been substituted for muscular energy. Energy consumption in today's agriculture includes tractor fuels, electricity, and the - 95 -
manufacture and transportation of fertilizers, feeds, pesticides, machinery and other inputs. Such agricultural uses accounted for about 3.5 percent of the total national enerqy consumption in 1972. In contradiction to some popular reports, our cereal crops produce about 3-5 calories of food and fiber energy for each calorie of energy consumed. Because plants are as yet the primary harvesters of free solar energy and the net producers of energy materials on a renewable base, agriculture is assuming a uniquely distinctive role in this nation's economic and energy trade balance. Furthermore, nonsolar energy is used in agriculture some 100-500 times more effectively than plants use sunlight. Utopian dreams of returning to a relatively primitive agriculture destitute of mechanical power, fertilizers, and pesticides are unrealistic because adeguate food for the world's population cannot be produced under such systems. Our analysis has indicated, however, that significant differences in efficiency of energy use exist among modern cropping systems. Consequently, adoption of more efficient systems can result in energy economies. Other potentials for assisting in the fuel crisis include developing plants with more efficient photosyn- thetic ability, minimizing tillage practices, utilizing energy in crop and animal wastes, and further enhancing the capability of ruminant animals to produce meat, milk, and fiber from roughages. PROJECTED UNITED STATES AGRICULTURAL PRODUCTION The growth in population in the United States and the world has increased the demand for food and fiber from agriculture, especially from United States agriculture. The consequent rapid disappearance of surplus land resources raises many important questions concerning future needs and alternatives. In recent years we have become more aware of the limits to expansion of productive capacity, which will have an impact on the prospects and potential for future growth. Several studies have been undertaken, in recognition of these questions, to evaluate and project future needs with respect to land and water resources and environmental implications. Carr and Culver (1972), for the United States Commission on Population Growth and the American Future, projected the - 96 -
productive capacity of United States agriculture to 2000 based on five scenarios derived from alternative combinations of assumptions concerning population growth, economic growth and restriction of production technology. With respect to production technology, the concern of the study "is chiefly, but not entirely, with the level of fertilizer and pesticide (insecticide, herbicide, fungicide) usage, the level of hormones and medications in animal feed, and the methods of animal waste disposal from concentrated feeding operations." Under all five alternatives, assumptions made about trends over the next 30 years in crop yields and the mix between present agricultural crops and possible substitutes resulted in an increase in harvested cropland from 344 million acres in 1970 to from 359 to 438 million acres in the year 2000. In three of the scenarios, this increase would be at the expense of the 60 million acres of cropland that were idle in 1970. In the other two scenarios, it would come in part from new cropland currently in pasture and range, timberland, or idle nonagricultural land. Fertilizer use was projected to increase in all cases, and pesticide use in several. The report concluded that "American agriculture appears capable, in terms of resource adequacy, technology, and structural flexibility, of meeting the challenges of the year 2000. Even under the most demanding assumptions about population and constraints on technology, food and fiber needs could be met without great difficulty, but would require some increase in prices." However, it was pointed out that one of the chief limiting factors tc expanded agricultural production in some areas may be the availability of water for irrigation. In this regard, a similar study was conducted by the National Hater Commission (1973), which was charged with the task of making projections of water requirements by 2000 and "identifying alternative ways of meeting these requirements." Of paramount importance in this study were the water needs of agriculture. Eleven alternative futures for agriculture were studied by Earl O. Heady, Howard C. Madsen and others forecasting national land use for the.year 2000 for various combinations of assumptions as to future farm policy, Dnited States population, water price, export level, and level of technology. For a free market serving a future population of 300 million with water prices and exports continuing at present levels, the acreage devoted to dryland annual crops was forecast to rise from 176 million acres in 1964 to 190 million acres in 2000. Irrigated annual cropland under the same conditions was forecast to drop from 13.3 to 6.1 million acres during the same time period. - 97 -
The most demanding projection assumed a population of 325 million, doubling exports, and advanced technology, leading to a land demand of 219 million acres for dryland annual crops and 8 million acres for irrigated annual crops. Even under these assumptions, 4.5 million acres of cropland and hayland would remain unused. "The results of the study, based on conservative yield trends, indicate that United States agriculture would not be faced with aggregative strains on food producing capacity and water supplies relative to needs in the year 2000 under any of the alternative futures considered." If more vegetable protein were consumed by people, both the land area and water required for irrigation would be decreased substantially. Concerning expansion of agricultural production and exports it was stated, "if the nation decides to plan for greater crop production, such a decision should be based on thorough consideration of all of the possible options, looking to achieving greater production goals in the most efficient way possible. And if as a matter of national policy the nation decides to increase its food export capability by a program of subsidizing the reclamation of land, a decision we do not recommend, it should do so in full awareness that the general taxpayer would be providing an indirect export subsidy for foodstuffs." In a 1974 summary of current and projected land uses in the United States, the ERS concluded that, with a population growth of 30 percent and a moderate increase in exports, the acreage of cropland harvested would decline from 286 million acres out of a total of 333 million in 1969 to 272 million acres harvested out of a total cropland acreage of 298 million in the year 2000. Even if there were no limitation on crop acreage and cost-price relations for agricultural projections were favorable, the acreage of cropland harvested would only be about 340 to 350 million. This level of land demand could be met by a more complete use of land currently in farms and through a continued increase in new croplands being developed at the current rate. In these projections, the acreage of land required for roughage and food grain production was expected to decrease by about 20 million, while land devoted to soybeans and other oil crops was projected to increase by 8 million acres. The BBS study concludes with a discussion of some of the problem areas which affect land usage and land use policy such as changes in demand for food and fiber and competing uses for land. It assumes that the available land and productivity levels are easily capable of providing for domestic demand and that export demand will determine the extent to which agricultural productivity is maximized. - 98 -
The projections of the National Hater Commission and the Commission on Population, Resources and the Environment rely on optimistic assumptions such as a continuation of past trends with no unexpected surprises. Since their publication, significant changes have taken place on the United States agricultural scene. Subsidized land reserves have already disappeared as farmers attempt to maximize food production. The combined effect of the devalued dollar with respect to rising real incomes in other countries (i.e. the U.S.S.R.) have placed an increased demand on agricultural exports. The importation of foreign oil places a tremendous burden on the balance of trade, for which agricultural exports are becoming increasingly important. We have our own need for building up reserves and for food security. Furthermore the vagaries of weather in the United States and worldwide, which are contributing to starvation, malnutrition, and rapid depletion of food reserves in many areas, while the world population continues to increase, add further impetus to the realization that we cannot afford to be complacent about our agricultural productive capacity both now and in the future. The Agricultural Production Efficiency Report (NRC 1975b) summarizes the above projections and its own evaluation in the following terms: Numerous projections have been made concerning population, changing nutritional habits, and food supplies. An analysis of these projections reinforces our concern that man's capability for foreseeing the future, even in terms of food supply, is fraught with many uncertainties. Past projections have usually underestimated the productivity of major crops in the United States. Recent projections to the year 2000 assume large increases in productivity to satisfy United States populations up to 280 million. At a population of 325 million, however, assuming increased exports, even the general adoption of advanced technology would place pressure on the nation's productive capacity. The optimistic projections place reliance on subsidized land reserves; but, as we have seen, most of these are already being returned to production. Current levels of food exports were not anticipated in any of the projections. Models and mathematics, can help us examine the consequences of alternative assumptions, but the assump- tions themselves are fraught with uncertainties. Resultant predictions and recommendations may deceive the unwary who assume without critical analysis of - 99 -
underlying premises that statistics are more accurate than verbal descriptions. For the next decade or so, available evidence indicates that food, feed, and fiber will be adequate for this country and for reasonable exports; but this adequacy does not preclude price increases, temporary local shortages, and drastic world shortages. Because of the increasing importance of agricultural exports in the nation's world monetary position and the pending world food shortages, there is an urgent need for agricultural research to receive increasing emphasis and much greater support. The future well-being of mankind could be at stake. In a recent study (NRC 1975a), the Board on Agriculture and Renewable Resources sought to identify technologies that could enhance food production in the United States and help to meet the food needs of a growing world population and the demand from increasingly affluent societies. The research and development programs recommended in that report are equally applicable to increased production of agricultural materials for industrial purposes. - 100 -
