Incremental improvements to agriculture have been which have included adoption of two-year crop rotations, precision agriculture technologies, classically bred and genetically engineered crops, and reduced- or no-tillage management systems.
US David researchers are recommending innovative agricultural systems such as organic farming, grass-fed and other alternative livestock production systems, mixed crop and livestock systems, and perennial grains. And it would require significant changes in market structures, policy incentives and public funding for agricultural science, according to the report.
Modern American agriculture has had an impressive history of increasing productivity that has resulted in affordable food, feed, fiber, and more recently, biofuel crops for domestic purposes and agricultural exports. Although the U.S. domestic and international markets are much larger than they were in the 1900s, farmers of the 21st century produce enough agricultural products to meet the current demands of both markets on the same acreage as a century ago. In addition, the average percentage of disposable income spent by U.S. consumers on food has declined from about 21 percent in 1950 to 9.4 percent in 2004.
Although small and medium-sized farms represent more than 90 percent of total farm numbers and manage about half of U.S. farmland and other farm assets, U.S. agriculture has become increasingly dependent on large-scale, high-input farms that specialize in a few crops and concentrated animal production practices for most U.S farm products. In 2007, the largest 2 percent of U.S. farms were responsible for 59 percent of total farm sales. Large farms have rapidly increased their share of total U.S. farm production value, while midsized commercial family farms that are important to rural community social and economic life are declining in number and importance. These trends can be partly attributed to technical innovations, economies of scale, and the increasing consolidation of food processing, distribution, and retailing sectors.
Many modern agricultural practices have unintended negative consequences, or externalized costs of production, that are mostly unaccounted for in agricultural productivity measurements or by farm enterprise budgets. Loss of water quality through nitrogen and phosphorus loadings in rivers, streams, and ground water contributes to dramatic shifts in aquatic ecosystems and hypoxic zones. Agricultural pesticides can contaminate streams, ground water, and wells. Excessive use of certain pesticides could be harmful to agricultural workers and might pose food safety risks. The nutrient density of 43 garden crops (mostly vegetables) has been shown to have declined between 1950 and 1999 in the United States, suggesting possible tradeoffs between yield and nutrient content. Agriculture contributes to total greenhouse-gas emissions, particularly carbon dioxide (CO2) from synthetic 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.
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 research and policy evolution that are designed to reduce tradeoffs and enhance synergies between the four goals and to manage risks and uncertainties associated with their pursuit.
Measuring Progress Toward Sustainability
Sustainability is best evaluated not as a particular end state, but rather as a process that moves farming systems along a trajectory toward greater sustainability on each of the four goals. For this report, the committee’s definition of sustainable agriculture does not make a sharp dichotomy between conventional and sustainable farming systems, not only because farming enterprises reflect many combinations of farming practices, organization forms, and management strategies, but also because most types of farming systems can potentially contribute to achieving various sustainability goals and objectives. Pursuit of sustainability is not a matter of defining sustainable or unsustainable agriculture, but rather of assessing whether choices of farming practices and farming systems would lead to a more or less sustainable system as measured by the four goals.
Finding ways to measure progress along a sustainability trajectory is an important part of the experimentation and adaptive management process.
If U.S. agriculture is to address the challenges both incremental and transformative changes will be necessary. Therefore, the committee proposes two parallel and overlapping efforts to ensure continuous improvement in the sustainability performance of U.S. agriculture: incremental and transformative. The incremental approach is an expansion and enhancement of many ongoing efforts that would be directed toward improving the sustainability performance of all farms, irrespective of size or farming systems type, through development and implementation of specific sustainability-focused practices, many of which are the focus of ongoing research and with varying levels of adoption. The transformative approach aims for major improvement in sustainability performance by approaching 21st century agriculture from a systems perspective that considers a multiplicity of interacting factors. The transformative approach would involve:
Developing collaborative efforts between disciplinary experts and civil society to construct a collective and integrated vision for a future of U.S. agriculture that balances and enhances the four sustainability goals.
Encouraging and accelerating the development of new markets and legal frameworks that embody and pursue the collective vision of the sustainable future of U.S. agriculture.
Pursuing research and extension that integrate multiple disciplines relevant to all four goals of agricultural sustainability.
Identifying and researching the potential of new forms of production systems that represent a dramatic departure from (rather than incremental improvement of) the dominant systems of present-day American agriculture.
Identifying and researching system characteristics that increase resilience and adaptability in the face of changing conditions.
Adjusting the mix of farming system types and the practices used in them at the landscape level to address major regional problems such as water overdraft and environmental contamination.
Soil and plant tissue tests, nutrient management plans, and precision agriculture technologies help farmers increase productivity, input-use efficiency, and economic returns, by reducing unnecessary use of agricultural fertilizers, pesticides, or water. Experimental and long-term field studies suggest that the impacts and economic benefits of those practices and tools can be variable across time and space.
Manure, compost, and green manure, as often used in organic systems, can reduce the need for synthetic fertilizer and hence reduce the energy used for fertilizer production. Many farms featured as case studies in this report make successful use of on-farm inputs for soil fertility (for example, animal and green manure), which insulates them from fluctuations in costs of synthetic fertilizer. Published studies, however, show variable results as to whether systems using commercial fertilizers or systems using cover crop-based or animal manure-based nutrient management have higher profits. Those studies often do not include environmental costs and benefits. Because the release of nutrients from manure, compost, and green manure depends on various factors, including temperature, soil properties, and microbial activities in soil, their application has to be timed appropriately to maximize nutrient uptake by plants, and hence productivity and net economic return.
Integrated pest management (IPM) research has identified promising options for improving soil suppressiveness and inducing crop resistance to some diseases and pests in addition to classical biological and ecological pest management. The need to study weeds, diseases, pests, and crops as an interacting complex has been recognized. Adoption of IPM has been reasonable on some crops, but overall IPM use is lagging despite its potential for reducing chemical use.
Livestock genetic improvement can contribute to improving sustainability by increasing feed-use efficiency and by selecting traits to improve animal health and welfare. Improvements in feed conversion through genetics, nutrition, and management have reduced manure and nutrient excretion per unit animal product produced and reduced land required for production.
Business and Marketing Strategies
Diversification of farm enterprises can provide multiple income streams for farming operations. Producing a range of farm crops and animal products can enhance the stability and resilience of farm businesses and can decrease the volatility of farm income. Studies that document the economic effects of modern strategies for enterprise diversification are sparse.
In addition to using production strategies that reduce costs, farmers can increase their farm-level income by increasing the value of their products through sales to niche markets (such as organic or health-food markets) or by selling their products directly to consumers (direct sales) to obtain a larger proportion of the consumers’ dollar spent on the product and to gain control over the prices they get for their products.
Practices for Improving Community Well-being
Diverse farm systems, diversified landscapes (for example, inclusion of non-crop vegetation), and farming practices that improve water and air quality can contribute to community and social well-being. Some direct marketing strategies, such as direct sales at farmers’ markets, community supported agriculture, farm-to-school programs, and agritourism, connect farmers to the community and can contribute to community economic security, but lack underpinning research and extension.