9
Conclusions and Recommendations

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 syn-



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9 Conclusions and Recommendations M odern American agriculture has had an impressive history of increasing produc- tivity 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 mar- kets 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 mid- sized 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 tech- nical innovations, economies of scale, and the increasing consolidation of food processing, distribution, and retailing sectors. Many modern agricultural practices have unintended negative consequences, or exter- nalized 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 agricul- tural 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 con- tributes to total greenhouse-gas emissions, particularly carbon dioxide (CO2) from syn- 

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0 TOWARD SUSTAINABLE AGRICULTURAL SYSTEMS IN THE 21ST CENTURY 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 ero- sion, 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 ge- netically 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 retire- ment 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. WHAT IS SUSTAINABLE AGRICULTURE? Defining Sustainable Agriculture 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 subjec- tive 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 chal- lenge 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 prog- ress toward the four sustainability goals. Such acceleration needs to be undergirded by

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 CONCLUSIONS AND RECOMMENDATIONS research and policy evolution that are designed to reduce tradeoffs and enhance syner- gies 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, organi- zation 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. Environmental, economic, and social indicators can be used to describe the performance of agriculture and to provide information on whether a farm, a farming system type, or agriculture at any scale is on a trajectory toward improved sustainability. Many indicators are means-based and others are outcome-based; both types have limitations and strengths. Efforts to develop indicators to assess social dimensions of agricultural sustainability are sparse. Some of the indicators being used, such as production energy costs and levels of implementation of best man- agement practices, are useful at many levels of aggregation from farm-level assessments to regional and national accounting. Yet, there are no agreed-upon standards regarding which indicators to use under different conditions. Few indicators have been validated by scientists, farmers, and the public. Developing consistent and effective indicators would facilitate assessment of the sustainability of farming practices or systems. Understanding the relationships between sustainability indicators and the outcomes they are meant to represent is a priority for future research. Farming systems that move toward greater sustainability on most, if not all, of the four goals generally strive to work with ecological and biogeochemical processes and cycles to maximize synergistic interactions and the beneficial use of internal resources, minimize dependence on external inputs, and use added inputs efficiently. Through those efforts, they potentially reduce discharges to the environment and additional waste disposal ac- tivities, provide economic resilience, and enhance social well-being. As exemplified in the case studies, many farmers who work toward improved agricultural sustainability manage their operations to encourage social and economic synergistic relationships on-farm and throughout the food chain. The overall sustainability or robustness of a farming system— the ability to adapt to stresses, pressures, and changes in circumstances over time—is a result of some mixture of resistance, resilience, and adaptability of the coupled biophysical and socioeconomic system. TOWARD AGRICULTURAL SUSTAINABILITY IN THE ST CENTURY Although all farms have the potential (and responsibility) to contribute to different aspects of sustainability, the scale, organization, enterprise diversity, and forms of market integration associated with different individual farms provide unique opportunities or bar-

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 TOWARD SUSTAINABLE AGRICULTURAL SYSTEMS IN THE 21ST CENTURY riers to improving their ability to contribute to global or local food production, ecosystem integrity, economic viability, and social well-being. Transformation of the agriculture sector will require long-term research, education, outreach, and experimentation by the public and private sectors in partnership with farmers and will not occur overnight. If U.S. agriculture is to address the challenges outlined in Chapters 1 and 2, both incre- mental and transformative changes will be necessary. Therefore, the committee proposes two parallel and overlapping efforts to ensure continuous improvement in the sustain- ability performance of U.S. agriculture: incremental and transformative. The incremen- tal 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 improve- ment in sustainability performance by approaching 21st century agriculture from a sys- tems 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 bal- ances and enhances the four sustainability goals. • Encouraging and accelerating the development of new markets and legal frame- works 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. INCREMENTAL APPROACH TO IMPROVING U.S. AGRICULTURAL SUSTAINABILITY The proposed expanded incremental approach would include focused disciplinary research on production, environmental, economic, and social topics, and policies (such as expanded agricultural conservation and environmental programs) to improve the sus- tainability performance of mainstream agriculture. For example, large livestock farms in the United States produce the majority of the nation’s meat and dairy products. Similarly, a large portion of corn and soybean are produced on highly mechanized grain farms that specialize in the production of a small number of crops and rely heavily on purchased farm inputs to provide crop nutrients and to manage pest, disease, and weed problems. Most, if not all, farms have adopted some practices for improving sustainability, and some farms, including large farms illustrated in the report’s case studies, are highly integrated, but such methods have not been adapted to all environments, and none of the practices have reached their full potential for adoption. Each of these production systems has fostered high productivity and low costs, but many have led to serious negative social and environmen-

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 CONCLUSIONS AND RECOMMENDATIONS tal outcomes (or externalized production costs) that could hinder agriculture’s progress toward improved sustainability. The negative outcomes have led to policy changes and publicly funded research programs explicitly designed to address those concerns. Efforts to improve the sustainability outcomes associated with mainstream production systems might be incremental in nature, but could have significant benefits given the dominance of those production systems in U.S. agriculture. Science—including biophysical and social science—is essential to understand agricul- tural sustainability. Science generates the knowledge needed to predict outcomes likely to result from different management systems, and it also expands the range of farming system alternatives that farmers and policy makers can consider. Science is critical for informing the political process. Research on an array of farming practices and farming systems has led to increased understanding of how each practice (including production practices and marketing strategies) can contribute to improving environmental, social, and economic sus- tainability of farms under different conditions. Examples of practices that have advanced the sustainability of U.S. agriculture toward some environmental, economic, and social goals are summarized in Box 9-1. Many practices listed in Box 9-1 have been implemented to different degrees and most serve as key components for fully integrated, sustainable farming systems. Although the research conducted to date has led to development of many farming practices that enhance environmental quality and the natural resource base, continuous research, extension, and experimentation by researchers and farmers are necessary to provide the toolkit necessary for farmers to adapt their systems to the changing envi- ronmental, social, market, and policy conditions to ensure long-term sustainability. The committee also notes that much of the research to date focuses on developing an approach or a practice to enhance a specific environmental quality (such as increasing soil organic matter) or solve a specific environmental problem (such as reducing or preventing soil salinization). Research on the economic and social dimensions of agricultural sustain- ability complementary to research on productivity and environmental sustainability is scarce despite its importance in providing farmers with knowledge to design systems that balance different sustainability goals and improve overall sustainability. Studies on economic and social sustainability are complicated by the fact that economic viability is influenced by market and policy conditions and that social acceptability of farms is influ- enced by the behavior of key actors (including farmers and consumers) and the values of community members. The lack of information on the economic viability of practices and approaches to improving environmental and social sustainability and on how market and policies influence the economics of those practices could be a barrier to wide adoption of those practices. Examples of research priorities aimed at understanding and devising best management practices for agriculture are listed in Box 9-2. Because research to develop practices and approaches for improving environmental sustainability and to qualify or quantify their economic and social impacts does not result in a marketable product for industry, this type of research is generally not attractive for private sector investment. Therefore, such research would have to rely on public funding and institutions, farmer organizations, and civil society sectors. RECOMMENDATION: The U.S. Department of Agriculture and state agricul- tural institutions and agencies should continue publicly funded research and development (R&D) of key farming practices for improving sustainability to assure that R&D keeps pace with the needs and challenges of modern agricul- ture. They should increase support for research that clarifies the economic and

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 TOWARD SUSTAINABLE AGRICULTURAL SYSTEMS IN THE 21ST CENTURY B OX - E xamples of Practices That Contribute to Sustainability Production Practices • onservation (or reduced) tillage systems have become common for many crops and soil types. As of C 2004, 41 percent of planted crop acreage was managed with conservation tillage. Water-caused soil erosion and surface runoff of nutrients, chemicals, and crop residues have been greatly reduced. Although no-till leads to savings on fossil fuel and labor, it could result in lower yields and greater difficulty with weed control than conventional till. Thus, the economic effect of no-till versus conventional till is unclear. • over cropping provides ground cover to protect soil. Cover crops can also be used to provide other ser- C vices, including maintenance of soil organic matter and provision of nutrients to subsequent crops (green manures), trapping excess nutrients in the soil profile following harvest of the primary crop, and preventing leaching losses (catch crops). However, cover crops are not widely planted because they require complex management skills and their seeding costs could be high. • rop diversity, including rotations, intercropping, and using different genetic varieties can con- C tribute to improving soil quality, enhancing ecosystem function, and managing pests and diseases. Although the use of diverse cropping systems has increased, it fluctuates widely with commodity prices. Diverse crop- ping systems require extensive knowledge and management skills to identify the right combination of crops to achieve multiple sustainability goals. Comparative economic studies reported economic advantages for diversified rotation in some cases and disadvantages in others. The variation in results is partly attributable to market and policy conditions. • raditional plant breeding and modern genetic engineering techniques will continue to be used to T develop crop varieties with increased yields, pest and disease resistance, enhanced water-use and nutrient- use efficiencies, and other important traits. Genetic engineering (GE) has the potential to contribute novel solutions for problems that could not be addressed with natural plant genetic resources or traditional plant breeding methods. New GE varieties would have to be tested rigorously and monitored carefully by objective third parties to ensure environmental, economic, and social acceptability and sustainability before release for planting. • any technologies for efficient water use such as metering, improved distribution of high-pressure water, M and low-pressure, directed-use systems offer promise to address water scarcity. Water reuse is another strategy for addressing water scarcity, but the biological and chemical quality of the reclaimed water would have to be monitored carefully. • est management practices (BMPs), including nutrient management planning, field buffer strips, riparian B area management, surface and subsurface drainage water management, and livestock manure manage- ment, have been developed to mitigate the runoff of agricultural nutrients and chemicals into the nation’s surface and ground waters. Effectiveness of BMPs at the watershed scale has been difficult to prove, in part because actions by individual farms might not be visible at the landscape scale. The benefits of BMPs can vary widely depending on characteristics of the landscape, weather events, and time lags between BMP adoption and physical changes in the dynamics of nutrient and chemical cycling on farm fields. social aspects of the many current and potential technologies and management practices and that addresses issues of resilience and vulnerability in biophysical and socioeconomic terms. TRANSFORMATIVE APPROACH TO IMPROVING U.S. AGRICULTURAL SUSTAINABILITY If major farming systems and aggregations of systems within key production regions have gradually evolved toward meeting some sustainability goals while moving toward unacceptable ends of the others, as indicated by scientific knowledge accumulated over

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 CONCLUSIONS AND RECOMMENDATIONS • oil and plant tissue tests, nutrient management plans, and precision agriculture technologies S 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. • anure, compost, and green manure, as often used in organic systems, can reduce the need for M 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 en- vironmental 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 ap- plication has to be timed appropriately to maximize nutrient uptake by plants, and hence productivity and net economic return. • ntegrated pest management (IPM) research has identified promising options for improving soil sup- I pressiveness 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. • ivestock genetic improvement can contribute to improving sustainability by increasing feed-use ef- L ficiency 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 • iversification of farm enterprises can provide multiple income streams for farming operations. Produc- D ing 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. • n addition to using production strategies that reduce costs, farmers can increase their farm-level income I 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 • iverse farm systems, diversified landscapes (for example, inclusion of non-crop vegetation), and farm- D ing 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. decades, then dramatic structural changes might be needed to meet the four sustainability goals. As the knowledge and understanding of agroecosystems improves, it is apparent that agricultural systems are dynamic with multiple interacting components. The chal - lenge is to devise approaches that maintain productivity and improve desired environmen- tal, economic, and social qualities simultaneously with maximum synergies and minimal tradeoffs. The transformative approach to improving agricultural sustainability would dramat- ically increase integrative research by bringing together multiple disciplines to address key dimensions of sustainability simultaneously beyond the agroecological dimension. It would apply a systems approach to agriculture that could result in production systems

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 TOWARD SUSTAINABLE AGRICULTURAL SYSTEMS IN THE 21ST CENTURY BOX - E xamples of High-Priority Research in an Incremental A pproach to Improving Sustainability Productivity and Environmental Research • ssessment of the effectiveness of cover crops in providing ecosystem services such as biological control A of agricultural pests and weed suppression, and nutrient and water retention. • ssessment of water reuse systems, surface and subsurface drainage systems, and advanced livestock A waste management systems that improve the effectiveness of wetlands, enhance water quality and water conservation, and reduce greenhouse-gas emissions. • omparative study on greenhouse-gas emissions and nutrient balances associated with different field C management practices for animal wastes and other organic amendments such as green manures and organic mulches and composts. • esearch and development of nonchemical alternatives (for example, biological control, biofumigation, R induced resistance, and soil suppressiveness) for managing weeds, pests, and disease as a complex. • esearch that identifies ecosystem benefits from changing agricultural practices, such as planting buffer R strips or hedgerows, reducing tillage, and using best management practices, at multiple scales. Socioeconomic Research • ssessment of how production practices might affect food attributes (such as pesticide residue, taste, A nutritional quality, and food safety). • esearch to assess and compare costs of different production practices and combination of practices R under different policy and market contexts. • esearch to document and analyze the economic sustainability of direct marketing—for example, to R review financial and labor returns to such marketing strategies as sales at farmers’ markets, community- supported agriculture, and farm-to-school programs. • esearch to document and analyze labor benefits, practices, and their trends in agriculture and their R effects on farm profitability. Policy Research • esearch to improve understanding of the intended and unintended consequences of federal farm, R food, and environmental policies that can affect the use of agricultural practices designed to improve sustainability. and agricultural landscapes that are a significant departure from the dominant systems of present-day agriculture. This approach would facilitate development of production ap- proaches that capitalize on synergies, efficiencies, and resilience characteristics associated with complex natural systems and their linked social, economic, and biophysical systems. It will emphasize integrating information about productivity, environmental, economic, and social aspects of farming systems to understand their interactions and address issues of resilience and vulnerability to changing climatic and economic conditions. Moreover, integration would include expanded attention to the role and development of new markets, new policies, and new approaches to research and development that are likely to sustain a systems-oriented agriculture. Options include development of appropriate price signals or incentives to farmers who seek to improve the sustainability of their farms across all four dimensions of sustainability and policies that are less likely to produce unintended consequences in one area of sustainability while addressing another area. Attention to pro- duction system types different from the dominant types (for example, an integrated crop and livestock system, a nonconfinement livestock production system, or highly diversi-

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 CONCLUSIONS AND RECOMMENDATIONS fied cropping systems that reduce reliance on purchased inputs) is desirable because the dominant system types might limit the range of technical or managerial possibilities in the pursuit of greater sustainability. A Systems Approach to Agricultural Research A systems approach to agricultural research is necessary to identify and understand the significance of the linkages between farming components so that a robust system that takes advantage of synergies and balanced tradeoffs can be designed. The report Alternative Agriculture published in 1989 by the National Research Council emphasized the importance of a systems approach to agricultural research. The growth of several systems-oriented approaches to farming, such as organic, biodynamic, and integrated crop–livestock farms, illustrates how farmers, industry, and academic communities can contribute to developing farming systems for improving sustainability. The committee provides two examples of how a systems approach is needed to inform design of farming systems that address two imminent challenges to the sustainability of U.S. agriculture. • Challenge 1: Producing cellulosic feedstock for biofuels. Scientific development of cellulose-producing crops and of the enzymes and production technologies needed to convert a range of feedstock to ethanol has been increasing. Federally set pro- duction targets for moving toward cellulose-based liquid fuels are in place. Early field-crop research indicates that perennial crops for cellulose production could contribute to reducing some of the negative environmental impact of agriculture on farmland and on aquatic systems through their proper placement in the landscape. Theoretically, different farming systems can be used to produce cellulosic feed- stock. If economic efficiency is an important goal, widespread large-scale produc- tion of cellulosic crop monocultures will likely dominate. Monocultures are likely to be easier to manage and to process with regard to harvesting and conversion to fuels, and therefore might reduce production costs. Monocultures, however, could generate unwanted environmental or social side effects. Efforts to consider each of the four sustainability goals in the development of cellulosic feedstock farming sys- tems will require attention to the costs and benefits of promoting greater enterprise and crop diversity both within farms and across landscapes. A holistic systems approach to research and development could identify opportunities for synergies and efficiencies that traditional disciplinary or production-focused research might miss. • Challenge 2: Social acceptability of concentrated animal feeding operations. Most commercial livestock production systems in the United States have evolved toward large-scale confinement production units that concentrate many animals in a small area. Some of those operations are geographically removed from the cropping sys- tems upon which they depend for feed and waste recycling. Systems other than concentrated confined animal systems are evolving for dairy cattle, beef cattle, and hogs, and to a small extent for poultry, mostly targeted to niche markets. Public concerns about nuisances, environmental pollution, and animal welfare associated with certain types of large animal confinement operations (for example, poorly managed concentrated animal feeding operations that reduce aesthetics of commu- nities or animal operations that use large quantities of subtherapeutic antibiotics) have intensified. Those concerns are reflected in social movements and market- place preferences. Few scientific studies compare alternative, integrated systems

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 TOWARD SUSTAINABLE AGRICULTURAL SYSTEMS IN THE 21ST CENTURY of animal care and management with large animal confinement systems, taking into account economic efficiency and productivity, environmental impacts, worker safety and well-being, food quality and safety assurance, and animal welfare. Ef- forts to study those issues as separate topics might not identify interactions and synergies. A holistic approach to research on livestock farming systems could be used to identify the relative strengths and tradeoffs for each alternative. Informa- tion from comparative studies would greatly inform public debates on the future of livestock production in the United States. Despite the need for research to balance and further enhance the four sustainability goals of agriculture, a large proportion of public research funding is devoted to improving productivity and reducing production costs. Only one-third of public research support is devoted to exploring environmental, natural resource, social, and economic aspects of farming practices. The report Alternative Agriculture emphasized the importance of a systems approach to agricultural research 20 years ago, yet the proportion of long-term systems agricultural research remains small. Ultimately, it will be more effective to structure farms and agricultural systems toward ecosystem stability rather than to address unintended consequences through piecemeal “technological fixes.” To pursue systemic changes in farming systems, R&D has to ad- dress multiple dimensions of sustainability (productivity, and environmental, economic, and social sustainability) and to explore agroecosystems properties, such as complex cropping rotations, integrated crop and livestock production, and enhanced reliance on ecological processes to manage pests, weeds, and diseases (recognizing their intercon- nectedness and interactions with the environment), that could make systems robust and resilient over time. Examples of transformative systems studies include: • Holistic comparison of existing organic, conventional, and innovative farming sys- tems in different environments to assess how each system performs with respect to local and regional sustainability goals and balances overall system efficiencies and resilience with environmental and social impacts. • Holistic comparison of the ability of confined animal systems and other alterna- tives to address production efficiency, food safety, environmental impacts or risks, animal welfare, and labor conditions. • Policies and legal frameworks that provide appropriate pricing and incentives to encourage the balancing of the four sustainability objectives and enhance system resilience and adaptability under dynamic conditions. RECOMMENDATION: Federal and state agricultural R&D programs should aggressively fund and pursue integrated research and extension on farming sys- tems that focus on interactions among productivity, environmental, economic, and social sustainability outcomes. Research should explore the properties of agroecosystems and the interdependencies between biophysical and socioeco- nomic aspects of farming systems, and how these interdependencies could make the systems robust and resilient over time. Application of a systems approach is not limited to the farm level. Understanding the positive and negative dynamics of agricultural systems at a landscape or community scale has been increasing, but the scientific foundation and data needed to develop a landscape approach to improving sustainability of agriculture is sparse. Research suggests that the

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 CONCLUSIONS AND RECOMMENDATIONS distribution of farm types and farming activities, along with other land uses, across a landscape could be designed to achieve greater robustness (productivity, resistance, and resilience), provide multiple ecological services, and improve the sustainability of local and regional agricultural systems that support personal and community well-being. In addition, effective public policy tools that are politically viable and effective in shaping patterns of the agricultural practices or land use at the landscape level are needed, but their development is in an early stage. Moreover, no single agricultural landscape pat- tern is likely to work in every location; rather, optimal designs would have to be adapted to local conditions and meet particular community needs. Water use for agriculture and agricultural impacts on water quality provide examples of why a systems approach at the landscape level is necessary for agriculture to move toward sustainability. • Incidence of water overdraft has been increasing in many agricultural areas, with the most serious being the drawdown of fossil water reserves in several areas. Extreme weather patterns and competition for scarce water from nonagricultural sectors will likely increase pressure on this finite resource. A traditional focus of im- proved water management has been to work with individual farming operations to adopt new technologies or water management systems. Innovations such as low-pressure distribution systems and demand-based scheduling offer promise for improving water-use efficiency. Although the impact of each individual farmer’s water use is small, collective action could have important effects on fossil water aquifers. Therefore, new institutional arrangements at the landscape scale might be needed to avoid continued drawdown of such collective resources. Moreover, systems-level interactions associated with the use of complexes of farming prac- tices (such as tillage, cropping patterns, and irrigation management) with ground water systems that connect neighboring farms and with increasing use of water for nonagricultural purposes are poorly understood. New technological and insti- tutional approaches will require an improved understanding of the dynamics of hydrologic processes within working agricultural landscapes. • The growing number, scale, and intensity of hypoxic zones are of increasing public concern. Agricultural nonpoint pollution is a major contributor to hypoxia. Many farming practices discussed in this report have potential to greatly reduce nitrogen and phosphorus runoff from agricultural lands. Efforts to address nutrient runoff problems have relied mainly on broad-based voluntary incentive programs tar- geted at individual farmers. However, not all fields, farms, or points of a watershed contribute equally to hypoxia. Landscape-scale planning tools, if made sufficiently user friendly and supported by relevant databases, could contribute to effective targeting of efforts at the farm, community, and watershed levels. Implementation of community and watershed planning would require the U.S. Department of Ag- riculture, U.S. Environmental Protection Agency, and the U.S. Geological Survey to work with local and state groups to carry forward farm- and landscape-level land- use plans for farm systems types, practices to be used, and targets for landscape diversity, beginning with the agricultural hotspots that contribute to lower water quality and hypoxia impact. Although a landscape approach to agricultural research could inform the design of agroecosystems to maximize synergies, enhance resilience, and inform what policies would be useful in influencing collective actions, programs to encourage such research do not exist. Examples of transformative landscape-scale research include:

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0 TOWARD SUSTAINABLE AGRICULTURAL SYSTEMS IN THE 21ST CENTURY • Develop systems-type mixes, patterns, and technologies for landscape diversity that maintain economic output while reducing overall water use. • Develop systems-type mixes and technologies to reduce nitrogen, phosphorus, and pesticide losses to downstream fragile water bodies, particularly in source regions responsible for hypoxia. • Develop tools for modeling of systems and patterns for multipurpose economic, aesthetic, and environmental impacts to enhance community well-being and as- sist in planning, local policy making, market identification, and farmer decision making. • Develop policies and legal frameworks that encourage cooperative watershed landscape and ground water management across field and farm boundaries. • Generate landscape design options to increase resilience and adaptability to chang- ing conditions using a combination of the above approaches. RECOMMENDATION: The U.S. Department of Agriculture should partner with the National Science Foundation, the U.S. Environmental Protection Agency, key land-grant universities, and farmer-led sustainable agricultural organizations to develop a long-term research and extension initiative that aims to understand the aggregate effects of farming at a landscape or watershed scale and to devise, encourage, and support the development of collective institutions that could enhance environmental quality while simultaneously sustaining eco- nomic viability and community well-being. Returns on research investments could be increased if research incorporates farmers’ knowledge effectively. Much of the technical and managerial innovation in agricultural sustainability has occurred through farmer innovation and experimentation. The federal Sustainable Agriculture Research and Education program and similar state-sponsored ef- forts have led to an increase in resources to support farmer-participatory research and farmer-led and -managed trials. When farmers are engaged as partners with scientists in innovation, development, extension, and outreach processes, the results of technology ad- aptation and adoption have often been more effective and sustained over time. In addition, farmers’ network and farmer-to-farmer mentoring programs can contribute to spreading information and knowledge gained from research and to adapting them to farmers’ local conditions. RECOMMENDATION: The U.S. Department of Agriculture and other federal and state agencies that support agricultural research should encourage research- ers to include farmer-participatory research or farmer-managed trials as a com- ponent of their research. Those agencies should strengthen initiatives for partici- patory education and peer-to-peer partnerships that could enhance information exchange and enhance farmers’ adoption of new practices and approaches for improving sustainability of agriculture. Efforts to engage farmers and citizens in research and outreach to improve agricultural sustainability will require institutional support. Cooperative Extension programs at the state and regional levels can play a critical role as facilitators and catalysts for fostering interaction among the various stakeholders, and for providing educational programs and access to current information.

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 CONCLUSIONS AND RECOMMENDATIONS Key Drivers of Change: Markets and Federal and Local Policies Other than available science, knowledge, and skills, the decisions of farmers to use particular farming practices and their ability to move toward more sustainable farming systems are influenced by many external forces, such as markets, public policies, and their own values, resources, and land tenure arrangements. These structural constraints are in turn influenced by the historic efforts of broad social movements and organized interest groups that have different perspectives about how agriculture should be organized and how food should be produced and distributed. With the growing popularity for a range of “environmentally friendly” products or of those that address a particular social concern (for example, animal welfare), consumer demand has opened up new markets for farmers to sell their value-trait markets products. Similarly, sustainability initiatives by large food retailers also have opened up new mar- kets for food products that are produced using certain practices or farming system types for improving sustainability. These emerging markets can motivate farmers to transition to sustainable farming systems that balance and meet multiple sustainability goals. Tools for marketing (for example, certification and branding) products that are produced using particular farming practices and systems that increase sustainability can enhance the value of those farm products, and thereby can contribute to not only environmental and social sustainability, but also to economic sustainability of the farm. However, the lack of appro- priate input suppliers, agribusiness professionals, marketing, and processing facilities can constrain the adoption of sustainable practices for agricultural production. The impact of public policies aimed at moving agriculture along the sustainability trajectory has been mixed. Some scholars attribute a decrease in the diversity of cropping systems, increases in the use of external farm inputs, and extensive hydrologic modification of landscapes in part to commodity support payments because these payments provide a strong incentive for farmers to focus on planting program crops by monocropping, and to maximize yields per dollar of cost (that is, to focus on only two of the four sustainability goals). Risk management policies can affect sustainability initiatives because some crop insurance products carry substantial subsidized premium structures that can potentially encourage farmers to grow monocrops, which could increase the vulnerability of highly erodible soils and reduce system resilience. Conservation programs are a mechanism for encouraging adoption of particular farming practices, but they are voluntary programs, often with a small proportion of farms participating. Although market, policy, and institutional contexts are important drivers of the trajec- tory of U.S. agriculture, the response of individual farmers to the incentives and disincen- tives created by market conditions and policy contexts can be diverse. Efforts to promote widespread adoption of different farming practices and systems for improving sustainabil- ity will require an understanding of how variability among individual, household, farm, and regional-level characteristics affect farmers’ response to incentives and disincentives. The scientific research to date is inadequate to assess the full impacts of current and pro- posed policy frameworks. RECOMMENDATION: Because of the critical importance of macro-structural or institutional drivers of farmer behavior, the U.S. Department of Agriculture should increase investment in empirical studies of the ways that current and proposed market structures, policies, and knowledge institutions provide op- portunities or barriers to expanding the use of farming practices and systems that improve various sustainability goals so that the department can implement

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 TOWARD SUSTAINABLE AGRICULTURAL SYSTEMS IN THE 21ST CENTURY changes in policies and institutions that are identified as effective to meeting those goals. Transformation of the agriculture sector will not occur overnight. It will take long- term research and experimentation by the public and private sectors in partnership with farmers. The two parallel approaches to improving sustainability proposed by the com- mittee would ensure incremental improvement toward sustainability, while long-term systemic changes in agricultural systems are being pursued. RELEVANCE OF LESSONS LEARNED TO SUB-SAHARAN AFRICA When considering the relevance of lessons learned in the United States to sub-Saharan Africa, it is important to recognize key differences between the two regions. African farmers produce a wide variety of crops using diverse farming systems across a range of agroeco- logical zones. Most systems are rain-fed, and many soils are severely depleted of nutrients. External inputs are expensive. High transportation costs and lack of infrastructure often inhibit access to outside resources and markets. Specific management approaches need to be developed in this context. Nonetheless, the concepts of sustainability and many of the broad approaches presented in this report are relevant and concur with conclusions from some recent international reports. The committee concluded that: • An interdisciplinary systems approach is essential to address the improvement and sustainability of African agriculture that recognizes the social, economic, and policy contexts within which farming systems operate. • Research programs need to actively seek input and collaboration from farmers to ensure research being conducted and technologies tested are relevant to their needs. • Women, who play a pivotal role in African agriculture, need to be provided with educational and training opportunities and be involved in the development and implementation of research agendas. • Technologies are needed to address soil, water, and biotic constraints, but they have to be integrated with local ecological and socioeconomic processes. Use of locally available resources would have to be maximized and combined with judicious use of external inputs when necessary. • Promising technologies and approaches include soil organic matter management, reduced tillage, integrated fertility management, water harvesting, drip irrigation, stress-resistant crop varieties, improved animal breeds, integration of crops and livestock, and use of global information systems for landscape and regional analy- sis and planning. • Expanding market access will be essential to increase productivity and enhance livelihoods in rural Africa. Investing in rural infrastructure could improve access to local, regional, and international markets. RECOMMENDATION: Agencies and charitable foundations that support re- search and development of sustainable agriculture in developing countries should ensure that funded programs emphasize a systems approach that reflects the need for adaptability of management strategies and technologies to dynamic local socioeconomic and biophysical conditions, and support efforts to increase market access.

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 CONCLUSIONS AND RECOMMENDATIONS People and organizations in developed countries and in developing countries can exchange useful information and ideas to solve problems related to sustainability of ag- riculture. Likewise, scientists and policy makers can learn from farmers and vice versa. Researcher and farmer partnerships and peer-to-peer exchanges among farmers could facilitate incorporation of local knowledge, making use of the best-available scientific process-level understanding, and enabling learning and developing knowledge systems to build the local capacity for improving agricultural sustainability. IN CLOSING This report identifies what is known about farming practices and systems that can improve sustainability. It discusses the potential benefits and risks if those practices are used and the potential synergies and tradeoffs that might present themselves if the prac- tices are used in combination in a farm system. The report also identifies knowledge gaps and areas where greater research is needed to help inform future decisions and to move agriculture along the sustainability trajectory. Filling those gaps will require some innova- tive new approaches in the realms of resilience thinking, complex systems science and management as applied to agroecosystems, and a better understanding of the economic and social drivers and outcomes of various farming approaches. The report findings show positive and promising outcomes among the production systems, farming businesses, and communities that are pursuing improved sustainability. It also reveals the importance of government agencies, farmers, food industry companies, communities, and consumers to support research, policies, programs, and institutions that help U.S. agriculture move along the sustainability trajectory.

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