thetic agrichemical production, nitrous oxide (N2O) from soil management activities, and methane (CH4) from enteric fermentation. Some modern agricultural practices adversely affect soil quality by affecting soil physical, chemical, and biological factors through erosion, compaction, acidification, and salinization. They also reduce biological activity as a result of pesticide applications, excessive fertilization, and loss of organic matter. Industrial confinement of livestock systems is associated with the decline in a number of minor breeds and the accelerated development of genetically similar hogs, poultry, and beef and dairy cattle. Concerns have been raised about the welfare of animals that are kept in large-scale confinement operations. Although on-farm productivity has been increasing, the aggregate value of net farm income received by farmers has not changed dramatically over the last 40 years, primarily due to rising prices of external inputs, including cost of hybrid and genetically engineered (GE) seeds, fuel, and synthetic fertilizers. More than half of U.S. farm operators work off-farm to supplement their income and to obtain health care and retirement benefit plans. The profitability of many U.S. farms, especially large grain producers, is partly determined by federal government commodity support programs.
Those changes in U.S. agricultural production systems have raised public concerns about the ecological sustainability of agriculture and the well-being of rural communities, farm families, farm laborers, and livestock. Questions have also been raised about whether agriculture can continue to supply adequate food, feed, fiber, and biofuel crops to meet the expanding needs of a growing and more affluent world population, and, if so, the tradeoffs and risks. At the same time, emerging constraints, such as the overdrafting of ground water and aquifers, loss of prime agricultural lands to urban development, and climate change, are posing unprecedented challenges to agricultural production and productivity in the United States. In addition, the large number of U.S. farmers who will likely retire in the next decade is raising concern about who will be the next generation of farmers.
Sustainability has been described as the ability to provide for core societal needs in a way that can be readily continued into the indefinite future without significant negative effects. Accordingly, measuring progress toward sustainability will be inherently subjective if different groups in society have different goals and objectives for agriculture. Even with broad agreement for certain goals, the relative importance assigned to one goal over another will be highly contested. Developing a widely accepted vision of what agricultural sustainability should be is beyond the scope of this report. However, four generally agreed-upon goals help define a sustainable agriculture:
Satisfy human food, feed, and fiber needs, and contribute to biofuel needs.
Enhance environmental quality and the resource base.
Sustain the economic viability of agriculture.
Enhance the quality of life for farmers, farm workers, and society as a whole.
The committee concluded that if U.S. agricultural production is to meet the challenge of maintaining long-term adequacy of food, fiber, feed, and biofuels under scarce or declining resources and under challenges posed by climate change and to minimize negative outcomes, agricultural production will have to substantially accelerate progress toward the four sustainability goals. Such acceleration needs to be undergirded by