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Toward Sustainable Agricultural Systems in the 21st Century 2 A Pivotal Time in Agriculture Modern agriculture, U.S. agriculture in particular, has had an impressive history of productivity (Gardner, 2002) that has resulted in relatively affordable food, feed, and fiber for domestic purposes, accompanied by substantial growth in agricultural exports. The population of the United States grew from 75 million in 1900 to 307 million in 2009 (U.S. Census Bureau, 2009). In 2008, agricultural exports reached a record $115 billion (USDA-ERS, 2009a). U.S. farm productivity has increased significantly over the last 50 years. Farm output in 2008 was 158 percent higher than it was in 1948 (Figure 2-1). Farm output was growing at an average annual rate of 1.58 percent, but aggregate inputs used increased only 0.06 percent annually (USDA-ERS, 2010). As a result of improved productivity, fewer farmers are producing more food and fiber on about the same acreage as the beginning of the century to meet the current demands of domestic and international markets; both markets are significantly larger now than they were in the 1900s. Furthermore, the growth in demand has been accompanied by a decline in the average percentage of disposable income spent by U.S. consumers for food. For example, in 1950, the average percentage of disposable income spent on food—for food at home and away from home—was 20.6 percent. By 2008, that amount was 9.6 percent (USDA-ERS, 2005a). Farmers are producing more food and fiber with less energy compared to 50 years ago (Figure 2-2; Shoemaker et al., 2006). They achieve higher output per unit energy input (Schnepf, 2004) using a number of strategies to reduce direct and indirect energy use. Direct energy use1 has been reduced as a result of advances in equipment efficiency, irrigation efficiency, adoption of no-till or conservation tillage, and other practices and technologies (USDA-NRCS, 2006). Indirect energy use2 has been reduced by increasing provision of 1 Direct energy use in farming includes fuels to operate cars, trucks, and equipment for preparing fields, planting and harvesting crops, and applying chemicals (Schnepf, 2004). 2 Indirect energy use in farming includes energy used off farm to manufacture farm inputs. Indirect energy use is dominated by fertilizer and pesticide use (Schnepf, 2004).
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Toward Sustainable Agricultural Systems in the 21st Century FIGURE 2-1 Agricultural productivity in the United States. SOURCE: USDA-ERS (2010). within-farm biogeophysical (ecosystem) services. For example, farming systems have been using crop rotations that could reduce pests and disease incidence so that pesticide use is reduced. Some farms use livestock manure to fertilize crops so that use of synthetic fertilizer is reduced. Precision agriculture for nutrient and pesticide application holds promise for reducing input use and maintain yield. Despite such advances, much progress in agriculture focuses on primarily one goal—satisfy human food, feed, and fiber fuel needs—and secondarily on the goals of enhancing environmental quality or resource base and of sustaining the economic vitality of FIGURE 2-2 Total farm output per unit of energy use over time. NOTE: Energy input use if total farm output was 1 in 1996. SOURCE: USDA-ERS (2009b).
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Toward Sustainable Agricultural Systems in the 21st Century agriculture. Agriculture worldwide is facing the daunting challenges of providing for an increasing population that has changing food consumption patterns under the constraints of natural resource scarcity, avoiding environmental degradation, climate change, and a restructuring global economy. In addition, consumers (including food buyers) are increasingly conscious about the sources of their food and how it is produced. Consumer concerns can translate into political and market demands for addressing the challenges. Thus, agriculture appears to be at a pivotal stage in terms of societal demands for agricultural systems with improved sustainability—that is, systems that address and balance social, economic, and environmental performance, and increase robustness in the face of new challenges. There are growing concerns about whether the trends of increasing productivity per acre of land can continue while maintaining or restoring the natural resource base upon which agriculture depends. Similarly, researchers and some members of the public are increasingly worried about many of the unintended negative consequences of agricultural production—for example, the effect of agriculture on environmental quality and ecosystem functioning, the potential risks of agricultural pollutants or risks of contamination of food and water by agricultural input to human health, and the safety and nutritional content of the food produced. Some observers raise the issues of how modern agriculture affects the well-being of farming communities, farm families, farm laborers, and livestock (Friedland et al., 1991; Vitousek et al., 1997). Those concerns have caused observers to question whether U.S. agriculture can continue to supply adequate quantities of reasonably priced food, feed, and fiber using conventional production methods. What are the tradeoffs and risks that will be required to maintain, and even increase, growth in productivity? Many unintended consequences of agricultural activities can be thought of as externalized costs of production, which are real, but mostly unaccounted for in productivity measures or internal financial budgets of farm enterprises. Societal concerns raise important public policy questions regarding the type, scale, and organization of U.S. agriculture that can best meet society’s needs in the future. Those concerns generate interest in alternatives to the current system of agricultural production that might increase the sustainability and broader performance of modern farming systems. The two major concerns of resource sufficiency and unintended consequences can be summarized in two questions: Are current agricultural practices and systems sustainable? If not, how can agriculture be moved toward a more sustainable trajectory? The purpose of this report is to identify what is known about farming practices and systems and their ability to address the identified concerns. This chapter provides a brief overview of how U.S. agriculture has evolved over the years to the current state. Despite the many positive changes (for example, increased productivity), farmers now face a different set of challenges related to environmental, social, and economic concerns. This chapter also discusses those challenges. A BRIEF HISTORY OF U.S. AGRICULTURE U.S. agriculture’s current structure and organization is a product of a long evolution (Batie, 2008). Since World War II, increased mechanization, rising productivity, and growth in nonfarm employment opportunities combined to produce more than a 60 percent drop in the number of farming operations and a doubling in average farm size in the United States (Gardner, 2002). Between 1982 and 2002, most types of crop farms have at least doubled in size, and the average size of livestock herds has increased by 2–20 times, depending on species (MacDonald and McBride, 2009). Growth in scale and productivity among the remain-
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Toward Sustainable Agricultural Systems in the 21st Century ing commercial farming operations has been sufficient to sustain steady annual growth in agricultural output of almost 2 percent a year (Fuglie et al., 2007). Unlike many sectors of the U.S. economy in which growth is associated with increased use of inputs, agricultural output has been increasing substantially despite a decline in such purchased inputs as capital, land, labor, and materials (Ball, 2005). For example, land used for crop production, as pasture or as idled cropland, has declined steadily since World War II. Although there is much year-to-year variation in the acreage of cropland used for crops from 1910 to 2005, the acreage in 2005 is comparable to that of 1910 (Figure 2-3). Yet those croplands are producing vastly more food, fiber, and fuel (USDA-NASS, 2002). Yields per acre have grown since 1935 at a rate of 2.1 percent per year (Gardner, 2002). U.S. corn yield, for example, has been increasing steadily (Cassman and Liska, 2007). Many other U.S. crops have similar histories of growth in their yields per acre (Gardner, 2002). The dramatic changes in farm size and productivity are associated with two important trends in the structure of the U.S. farm sector: increased concentration and specialization in farm production. In the first instance, a smaller fraction of farms is increasingly responsible for producing the overwhelming bulk of American food output (Gardner, 2002). In 2002, for example, the top 6.7 percent of the largest farms in the United States (143,547 farms) accounted for 75 percent of total farm sales (USDA-NASS, 2002). In the second instance, farms have become increasingly specialized since the early 1960s, and the average number of major commodities raised on a typical farm declined from 5.6 in 1920 to 1.3 in 2002 (Gardner, 2002). Prior to World War II, almost all U.S. farms raised a diverse set of commodities (particularly chickens, pigs, cattle, potatoes, hay, and corn). The growing specialization of production is associated with technological change, increased labor productivity, and growing economies of scale3 (Hallam, 1993; MacDonald and McBride, 2009). One of the most striking specialization trends in U.S. agriculture has been the decoupling of crop and livestock production (Russelle et al., 2007). The growth of highly specialized confinement livestock operations has led to greatly increased animal densities (livestock units per acre of available land) and the geographic movement of poultry, hog, and dairy production away from traditional feed grain production regions (McBride, 1997; Hart, 2003). The dramatic changes in U.S. agriculture over the last half-century have been influenced by four major drivers: new agricultural technologies, expansion and commercialization of markets, government programs, and research and development. New agricultural technologies. Resource sufficiency concerns over the last century were overcome by the development and diffusion of new agricultural technologies, rather than increased land area devoted to farming (Figure 2-3). In the case of corn, for example, much of the increase in productivity can be attributed to increased yields per unit land as a result of improved breeding, fertilizer use, pest management, and irrigation (Figure 2-4) (Tilman, 1999; Cassman and Liska, 2007). Most technological innovations have favored larger farms (Halloran and Archer, 2008) because mechanical equipment has to be used for a minimum number of hours or acres to achieve efficiency. Modern crop varieties and off-farm inputs have become tools used by some farmers to manage the risks associated with large-scale monoculture farming (Halloran and Archer, 2008). Mechanization in agriculture and its improvement over time has reduced labor requirements and increased labor productivity (Sassenrath et al., 2008). The number of workers per acre of production has declined significantly in the last century (Schjonning et al., 3 “Economies of scale” refers to the reduced costs per unit produced as farm output increases.
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Toward Sustainable Agricultural Systems in the 21st Century FIGURE 2-3 Acreage of cropland used for crops. SOURCE: USDA-ERS (Vesterby et al., 2004). 2004). Farms and ranches in the United States are now managed by less than 2 percent of the population (Vesterby and Krupa, 2001), but occupy about half of the total acreage of the country (Lubowski et al., 2006). Expansion and commercialization of markets. The increased production and productivity of U.S. agriculture has occurred in tandem with a significant expansion of export markets for U.S. farm products and the rapid consolidation and vertical integration of national and global food processing, distribution, and retailing sectors (MacDonald and McBride, 2009). While U.S. population growth has increased by roughly 1 percent annually FIGURE 2-4 U.S. maize yield trends, 1966–2005, and the technological innovations that contributed to this yield advance. SOURCE: Cassman and Liska (2007). Reprinted with permission from Wiley.
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Toward Sustainable Agricultural Systems in the 21st Century since 1970, food production has increased at twice that pace. Increased domestic per capita consumption of food (including changes in diets to include greater consumption of meats and processed foods) and growing international trade have been important contributing factors driving increased production of the farm sector. At the same time, the processing and distribution of U.S. farm products have become controlled by a much smaller number of highly integrated national and global firms than there used to be (Hendrickson and Heffernan, 2007). Demands by processers and retailers for consistent, high-quality products on a year-round basis have influenced patterns of technological innovation and structural change at the farm level. Government programs. U.S. agricultural policy was initiated during the Great Depression to address low farm income. The U.S. Farm Bill is enacted every four to five years and has a major influence on land management decisions and choice of crops (Halloran and Archer, 2008). The Farm Bill’s commodity programs have had four major effects: (1) scale—total production or total acreage, (2) mix of commodities—which crops or livestock are grown or produced, (3) location—where crops or livestock are grown and produced, and (4) intensity—input use per acre for a specific crop-location combination or density of livestock production per acre (Frisvold, 2004). In addition to the commodity programs, the Farm Bill has provisions for subsidies and technical assistance for conservation, and for nutritional programs and food buying assistance for lower income consumers. Research and development. Many technological innovations that accelerated growth in productivity came from agricultural experiment stations and colleges of agriculture in land grant universities. Innovations in information and marketing technology also facilitated farmers’ adoption of new production methods (Gardner, 2002). The technological development and innovations were induced and supported by complementary government farm agricultural policies. An example is the large public investments in infrastructure development—for instance, development of water resources for irrigation, which vastly improved the ability to provide food and fiber in arid regions. As a direct result of those taxpayer-supported programs, farmlands that receive subsidized irrigation grew to almost 40 million acres by 1970 (Cochrane, 1979). U.S. AGRICULTURE TODAY While the overall trends in U.S. commercial agriculture have been toward fewer, larger, and more specialized farms, the farm sector remains diverse (Hoppe et al., 2007). Using census data, researchers at the U.S. Department of Agriculture (USDA) have identified several important clusters of farm “types” in the United States (Box 2-1). The importance of each farm type across a wide range of indicators is summarized in Table 2-1. As a result, the management practices used on many different types of U.S. farms will each contribute to the overall sustainability performance of the U.S. farm sector. In addition, efforts to assess and improve the sustainability of U.S. farming are likely to require distinctive strategies appropriate for different types of farms. The data in Table 2-1 indicate the smallest family farms in the United States (those with sales under $100,000) represent over 80 percent of total farm numbers, but produce less than 10 percent of total farm sales. Because a farm is defined in the Census of Agriculture as any operation that sold or could have sold more than $1,000 worth of agricultural products, many of those small farm operators might not even consider themselves to be farmers, and most of those farms are run as recreational or lifestyle farms by people who rely mainly on off-farm income or who are retired. That group of small farms, however, still manages about a third of U.S. cropland and farmland.
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Toward Sustainable Agricultural Systems in the 21st Century BOX 2-1 Farm Typology Developed by the U.S. Department of Agriculture Economic Research Service The U.S. farm sector is so diverse that statistics summarizing the sector as a whole can be misleading. The USDA Economic Research Service (ERS) has developed a classification typology to identify relatively homogenous subgroups of U.S. farms. The typology is based largely on farm sales, organizational structure, and the operator’s primary occupation. The farm classification developed by ERS focuses on the “family farm,” or any farm organized as a sole proprietorship, partnership, or family corporation. Family farms exclude farms organized as nonfamily corporations or cooperatives and farms with hired managers. Small Family Farms (sales less than $250,000) Limited-resource. Farms with gross sales less than $100,000 in 2003 and less than $105,000 in 2004. Operators of limited-resource farms must also have received low household income in both 2003 and 2004. Household income is considered low in a given year if it is less than the poverty level for a family of four, or it is less than half the county median household income. Operators may report any major occupation except hired manager. Retirement. Small farms whose operators report they are retired (excludes limited-resource farms operated by retired farmers). Residential/lifestyle. Small farms whose operators report a major occupation other than farming (excludes limited-resource farms with operators who report nonfarm work as their major occupation). Farming-occupation. Farms whose operators report farming as their major occupation (excludes limited-resource farms whose operators report farming as their major occupation). Low-sales. Gross sales of less than $100,000. Medium-sales. Gross sales between $100,000 and $249,999. Large-Scale Family Farms (sales of $250,000 or more) Large family farms. Farms with sales between $250,000 and $499,999. Very large family farms. Farms with sales of $500,000 or more. Nonfamily Farms Nonfamily farms. Farms organized as nonfamily corporations and cooperatives, as well as farms operated by hired managers. Also includes farms held in estates or trusts. SOURCE: USDA-ERS (2000). The mid-sized family farms (sales between $100,000 and $500,000) are examples of the prototypical “family farm” that has captured much of the public imagination and public policy debates over the future of American agriculture (Browne et al., 1992). According to the 2007 census, these mid-sized farms represented just under 10 percent of all U.S. farms, produced 16.5 percent of all farm sales, and managed another quarter of the nation’s farmland and nearly 30 percent of its cropland. Small and mid-sized family farms together owned two-thirds of the total value of farmland, buildings, and equipment and managed roughly 60 percent of all U.S. farmland and cropland in 2007. Therefore, they will continue to play an important role in efforts to improve the environmental footprint of agriculture, and their experiences and activities will continue to shape the social and economic well-being of farm families and agricultural communities. Interestingly, the proportion of small and mid-size operations that have chosen to participate in federal land conservation programs is larger than that of
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Toward Sustainable Agricultural Systems in the 21st Century TABLE 2-1 Farm Typology Class and the Relative Contribution of Each Class to Various Farm Indicators in 2007 Indicator Farm Typology Class Small Family Farms (Sales < $250,000) Large Family Farms (Sales $250,000+) Limited- Resource Farms Retirement Farms Residential-Lifestyle Farms Farming-Occup. (Sales < $100,000) Farming-Occup. ($100,000–$249,999) Large Family Farms ($250,000–$499,999) Very Large Family Farms ($500,000+) NonFamily Farms (Percent of U.S. Total) Farms 14.0 20.7 36.4 11.7 4.5 3.9 4.6 4.1 Value of Productiona 0.9 2.3 3.7 2.2 5.8 10.7 54.3 22.9 Total Government Payments 3.3 9.9 12.1 7.2 11.0 16.1 33.1 7.4 Production Expenses 1.7 3.2 5.8 3.2 5.4 9.5 48.6 22.5 Net Cash Farm Income –1.3 1.4 –1.2 0.8 7.4 13.9 60.5 18.4 Value of Farm Assetsb 5.9 11.8 18.1 8.9 8.4 11.5 25.2 10.3 Hired Farm Workers 3.5 7.6 11.7 6.9 6.2 8.4 34.1 21.6 Farmland 4.6 9.7 13.1 9.5 11.3 13.3 22.9 15.6 Cropland 3.6 8.0 11.0 7.4 11.5 16.6 34.0 7.9 Irrigated Land 1.5 3.0 4.6 3.8 7.4 13.1 50.6 16.0 Conservation Program Landc 7.5 26.1 26.6 11.6 6.3 5.8 7.6 8.5 Crop Insurance Acresd 1.2 2.8 5.0 4.8 13.2 21.0 44.3 7.6 Organic Farms 16.4 12.1 27.3 19.6 8.1 4.6 4.9 7.2 Organically Certified Land 6.0 6.5 11.8 13.4 16.3 15.2 19.4 11.3 Organic Produce Sales 1.5 1.7 3.2 4.3 9.0 10.5 41.6 28.1 aMarket value of agricultural product sales. bCombined value of land, buildings, machinery, and equipment. cAcres enrolled in Conservation Reserve Program, Wetlands Reserve Program, Conservation Reserve Enhancement Program, and farmable wetlands programs. dAcres enrolled in crop insurance programs. SOURCE: 2007 Census of Agriculture.
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Toward Sustainable Agricultural Systems in the 21st Century large operations. Eighty-four percent of all land in federal land conservation programs is managed by small and mid-sized farms. Small and mid-sized farms received 88 percent of U.S. total government payments for conservation programs in 2006 (Hoppe et al., 2008). In addition, 70 percent of organically certified land in the United States was managed by small and mid-sized farms in 2007 (although they accounted for only 30 percent of total organic product sales). In contrast to the small and mid-sized farms, million-dollar farms—that is, those with annual sales of at least $1 million—accounted for nearly half of U.S. farm product sales in 2002, even though there were only about 35,000 of them. They represent only 2 percent of all U.S. farms (Hoppe et al., 2008). Most million-dollar farms were operated as family businesses, and many reflect joint operations that support multiple family members and households. These types of farms particularly dominate the value of U.S. production of high-valued specialty crops (72 percent), dairy products (59 percent), hogs (58 percent), poultry (55 percent), and beef (52 percent). In some crops, production is concentrated. For example “[d]ata on acres harvested [obtained] from the 2002 Census of Agriculture suggest that some specialty crops occur on a relatively small number of farms. For example, the 58 largest producers of head lettuce (out of 830 total producers) in 2002—each harvesting at least 1000 acres of the crop accounted for 65 percent of the total acreage in head lettuce. As another example, the 77 largest broccoli producers (out of 2,493 total producers)—each with at least 500 harvested acres of the crop—accounted for 69 percent of the total harvest acres” (Hoppe et al., 2008, p. 34). Because of economies of size, and as illustrated in Figure 2-5, those large farms tend to have profit margins that give them a competitive edge when compared to similar, but smaller farms. The million-dollar farms can take better advantage than the small farms of technological changes, economic and financial innovations, business management principles, and coordination with suppliers and processors (Gray and Boehlje, 2007). Relatively few of the million-dollar farms specialize in crops that are covered by Farm Bill commodity programs, although the 44 percent of these farms that did participate in FIGURE 2-5 Operating profit margin, by sales class in 2006. SOURCE: USDA, Economic Research Service, 2006 Agricultural Resource Management Survey, Phase III (as cited in Hoppe et al., 2008).
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Toward Sustainable Agricultural Systems in the 21st Century commodity programs received a total of 16 percent of all commodity program payments. The million-dollar farms account for 62 percent of all U.S. farm products produced under contracts with processors and other end buyers. Very large farms were somewhat less likely to participate in federal conservation programs than mid-sized farms. In 2006, 6 percent of total government conservation spending was distributed to the million-dollar farms (Hoppe et al., 2008). Another important form of agricultural diversity in the United States becomes apparent when examining the acreage planted to various crops or used for livestock production. Efforts to address the sustainability of U.S. agriculture will need to confront the distinctive opportunities and challenges associated with production of different types of commodities. The most commonly raised commodities in U.S. agriculture are beef cattle, horses, and forages (each raised by more than a quarter of U.S. farms). However, the most economically important commodities—grains, poultry, dairy products, and specialty crops—are typically raised on a small fraction of U.S. farms (Table 2-2). Those commodities also represent the production systems that use most of the energy, fertilizers, agrichemicals, and hired labor in the United States. From a landscape perspective, most U.S. cropland is planted to TABLE 2-2 Relative Importance of Different Commodities in U.S. Agriculture, 2002 Commodity Type Percentage of U.S. Total Farms Raising Commodity Farm Sales from Commodity U.S. Harvested Cropland Livestock Beef cows 37.4 22.5 na Horses 25.5 0.7 na Sheep and goats 7.7 0.3 na Poultry 4.6 11.9 na Milk cows 4.3 10.1 na Hogs and pigs 3.7 6.2 na Crops Forages (all) 41.6 3.0 21.2 Grains and Oilseeds (any) 22.8 19.9 66.7 Corn grain 16.4 22.5 Soybean 14.9 23.9 Wheat 8.0 15.0 Corn silage 4.9 2.2 Oats 3.0 0.7 Barley 1.2 1.3 Rice 0.4 1.1 Fruit, Nuts, and Berries 6.2 6.9 1.9 Vegetables and Potatoes 3.0 6.4 3.0 Nursery/Greenhouse 2.6 7.3 0.3 Tobacco 2.7 0.8 0.1 Cotton 1.2 2.0 4.1 NOTES: Percent of farms raising each commodity = Number of farms reporting inventories of each livestock species or number of farms reporting acreage of each crop/Total number of farms in the United States. Percent of U.S. farm sales by commodity = Sales of each commodity/Total U.S. farm sales. Percent of U.S. harvested cropland = Percent of harvested acres in each crop/Percent of all U.S. harvested cropland.
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Toward Sustainable Agricultural Systems in the 21st Century corn, soybean, forage crops, and wheat. Efforts to significantly increase cropping diversity, change tillage practices, or reduce nonpoint source pollution from cropping activities will need to emphasize those commodity production systems. The geography of U.S. agriculture is shaped by a range of biophysical, economic, and demographic factors that vary widely by region. Researchers at USDA demonstrate the landscape diversity by combining data on county-level farm characteristics with data on natural resource conditions, such as areas with similar physiographic, soil, and climatic traits. (For maps and definitions, see USDA-ERS, 2009c.) They identified nine major “farm resource regions” in the United States (Heimlich, 2000). Figure 2-6 describes these regions and highlights the importance of them, the combination of which accounts for almost half of U.S. farms, 60 percent of the value of production, and 44 percent of U.S. cropland. The three regions are the “heartland” region in the corn belt, where cash grain and cattle and hog production dominates; the “fruitful rim” along the Pacific coast, southern Texas, and Florida where large farms are concentrated and fruit, vegetable, nursery, and cotton production dominates; and the “northern crescent,” a traditional dairy and cash grain region. Farm commodity systems and production practices often differ markedly across the various farm resource regions in the United States. FIGURE 2-6 Farm resource regions in the United States. SOURCE: USDA-ERS (Heimlich, 2000).
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Toward Sustainable Agricultural Systems in the 21st Century suggested that modern plant breeding has been able to nearly triple the per-acre yield of grains, vegetables, and fruits, but that the increases in size and yield have diluted the crops’ nutritional quality and flavor. He reviewed published literature and suggested that the concentrations of essential minerals such as zinc and iron in fruits, grain, and vegetables have been declining over time. Other than Halweil’s metaanalysis, most studies on nutritional quality and flavor of crops focus on the effect of cultivar (Koudela and Petkikova, 2007, 2008) and farming practices (Magkos et al., 2003; Mäder et al., 2007) or storage and processing of produce on those qualities. Pesticide residue in food is a concern of many consumers (Tucker et al., 2006), even though the Food and Drug Administration (FDA) has been monitoring pesticide residue in food since 1993. FDA concluded that levels of pesticide residues in the U.S. food supply are overwhelmingly in compliance with EPA’s permitted pesticide uses and tolerances (FDA, 2009). Given the level of compliance with respect to pesticide use, a more serious food safety concern appears to be food-borne illnesses. Mead et al. (1999) estimated that food-borne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. More than 200 known diseases are transmitted through food and contamination of food-borne pathogens that can occur in various stages of production and processing (Oliver et al., 2009). Food safety begins with the soil, plant, or animal. Manure is a principal source of enteric pathogens on the farm (Doyle and Erickson, 2008). Fecal contamination of crops and of animal products at harvest can spread pathogenic organisms to humans. Enteric pathogens from parent flocks of poultry can be transmitted to progeny (Methner et al., 1995; Cox et al., 2000), as in the case of eggs. Therefore, food safety concerns need to be addressed in ways that consider not only postharvest handling and processing, but also how food is produced on the farm. Food Security Concerns Although the U.S. farm sector consistently produces vastly more crop and livestock products than required to meet the basic nutritional needs of U.S. citizens, a significant number of Americans still suffer from malnutrition or hunger each year. The USDA Economic Research Service (ERS), for example, estimates that 11.1 percent of U.S. households (or 13 million households) are food insecure in that they do not have enough access to food at all times for an active healthy life for all household members (Nord et al., 2008). In addition, an estimated 833 million people in developing countries are considered food insecure (Shapouri et al., 2009). While production of an adequate amount of food is a necessary prerequisite to solving food insecurity (by ensuring a sufficient supply of food products and by keeping the cost of food down), most scholars argue that other factors are important contributors to the problem. Specifically, many households lack sufficient income to afford to buy even low-priced foods. Although farm production cost affects the price of food, it is one of many components of food price in the market place. Some households live in so-called “food deserts” that do not have ready access to grocery stores or other sources of balanced, fresh, and nutritious food products. Setting up farmers’ markets in those neighborhoods could potentially alleviate that problem (IOM and NRC, 2009). Domestic and international food insecurity is also aggravated by volatility in farm commodity prices associated with climate variability, shifts in global market supply and demand conditions, and competition for agricultural commodities from the bioenergy sector.
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Toward Sustainable Agricultural Systems in the 21st Century Animal Welfare Concerns Consumers’ concern about animal welfare is not a new phenomenon, but pressures from consumer groups and supply chain management companies have prompted increased attention on animal health and welfare (Mitchell, 2001; Johnson, 2009). Concerns about animal welfare include animal housing, access to food and water, health (and disease management), and behavior (Keeling, 2005).There is an increasing awareness among consumer groups about some animal-rearing practices (Petherick, 2007) and concerns among animal scientists of tradeoffs in animal health and welfare that are associated with alternative systems (Mench, 2008), such as in organic systems where antibiotic use is prohibited. Community Well-Being The idea that rural towns surrounded by small family farms provide the bedrock of strong democratic values and community life has been a powerful image in American culture (Wirzba, 2003). Similarly, as society has become less rural and agrarian, and as agricultural operations have increased in size and scale, there have been repeated concerns expressed about possible negative effects on the social and economic welfare of communities (Lobao and Meyer, 2001; Berry, 2004). Observers have linked the process of farm consolidation, increased specialization and mechanization, and growing vertical integration to the slow erosion of traditional rural community life and the decline of farm-dependent community economies. More recently, scholars have pointed to the consolidation of the larger agrifood system and the increased importance of vertical economic relationships (as opposed to horizontal linkages among local firms) as a source of some community problems. Most empirical research on this topic has focused on comparing the social and economic linkages between large versus small farms and their surrounding communities. Lobao and Stofferahn (2008, p. 223) recently reviewed more than 50 empirical studies of the impact of industrialized farming systems on local communities. They note that socioeconomic impacts can reflect both direct effects “through the quantity of jobs produced and the earnings quality of those jobs; by the extent to which these farms purchase inputs and sell outputs locally” and indirect effects where the structure of the farm labor force and farm purchasing patterns can affect “total community employment, earnings, and income (for example, economic multiplier effects); the local poverty rate; and the level of income inequality.” They report that the majority of studies (57 percent) found negative effects of industrialized agriculture on community well-being, 25 percent found mixed impacts, and 18 percent found no significant impacts. Generally speaking, individual-level studies and regional models demonstrate that the net effect of farm size changes on local farm-related economic activity appears to depend more on trends in the overall volume of farming activity (for example, total regional livestock inventories or acreages devoted to certain crops) than on the size distribution of farms per se. In addition, the direct and indirect economic impacts of farm input purchases from and sales to local businesses appear to generate less total aggregate economic activity than the total amount of net farm income among farm households (Dobbs and Cole, 1992). That evidence suggests that maintaining farm profitability is a critical link to ensuring that farm dollars circulate in the local economy. By contrast, in a study of dairy farms in Austria, Kirner and Kratochvil (2006) found that larger farms generated more net income per unpaid family work unit, but argued that smaller farms exhibited greater enterprise diversification and as a result generally contributed more to the regional economy. Despite
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Toward Sustainable Agricultural Systems in the 21st Century disputes about how to achieve strong community agricultural connections, there is a growing interest in finding ways to maintain a local and robust agricultural sector that has strong community ties. Community Health and Quality of Life Although some farming operations can improve the aesthetics of the landscape, others such as large-scale confined animal feeding operations (CAFOs) can negatively affect the health and quality of life in nearby neighborhoods (Wing et al., 2008). Wing and Wolf (2000) found residents in the vicinity of hog operations in eastern North Carolina reported increased occurrences of headaches, runny nose, sore throat, excessive coughing, diarrhea, and burning eyes as compared to residents of the community with no intensive livestock operations. Quality of life, as indicated by the number of times residents could not open their windows or go outside even in nice weather, was similar in the control and the community in the vicinity of the cattle operation but greatly reduced among residents near the hog operation. Respiratory and mucous membrane effects were consistent with the results of studies of occupational exposures among swine confinement-house workers and previous findings for neighbors of intensive swine operations. Horrigan et al. (2002) suggested that the proliferation of large-scale confinement animal agriculture creates environmental and public health concerns, including pollution from the high concentration of animal wastes and the extensive use of antibiotics, which may compromise their effectiveness in medical use. Using antibiotics to treat animals with clinical infections has undoubtedly contributed to improving the health and welfare of farm animals over the years. Therapeutic use of antibiotics reduces the economic losses endured by farmers as a result of animal sickness and death. Antibiotics have been used subtherapeutically to promote growth, improve feed efficiency, and reduce incidence of certain diseases (Doyle, 2001). The effect of antibiotics as a growth promoter of agricultural animals was discovered in 1940s (Castanon, 2007). FDA approved the use of certain antibiotics in animal feed in 1951. The antimicrobial drugs permitted for use in food animal production represent all major classes of clinically important drugs (Silbergeld et al., 2008). The accumulation of antibiotic-resistant bacteria as a result of antibiotic use in agricultural animals has been documented (Teuber, 2001). A preliminary study by Chander et al. (2008) showed that antibiotic-resistant bacteria are more prevalent in turkey farms that use antibiotics subtherapeutically compared to those that do not use antibiotics. The European Union withdrew approval for antibiotics as growth promoters in poultry feeds out of concern for development of antimicrobial resistance and about transference of antibiotic resistance genes from animal to human microbiota (Castanon, 2007). SYSTEMS APPROACH TO IMPROVING THE SUSTAINABILITY OF AGRICULTURE U.S. agriculture has been meeting the demands of higher production (Cassman and Liska, 2007), but with unintended costs as discussed above. At the same time, land-grant university research and farmer or practitioner experiences have improved the knowledge and understanding of how to improve yield and reduce agriculture’s impact on the environment and resource use. The accumulated knowledge has led to actions being taken that suggest promising directions to pursue for enhanced sustainability in farming systems. The research on the application of approaches that improve sustainability of agriculture suggests that agriculture has the potential to meet the demand of food, feed, and fiber; reduce its environmental footprint; and address other social concerns such as animal wel-
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Toward Sustainable Agricultural Systems in the 21st Century fare and labor justice, but gaps in understanding remain. For example, how the collective actions of a number of farms could improve sustainability on a landscape scale is not well studied. Filling those gaps of understanding will require innovative new approaches, in particular in the realms of complex systems science and management as applied to agro-ecosystems, and a better understanding of economic and social outcomes of the farming approaches. SUMMARY U.S. agriculture has celebrated much success in the last 50 years as farmers continue to increase productivity on about the same acreage of farmland and increase energy efficiency in their production systems. However, agricultural sustainability is characterized by not only productivity and efficiency, but also by its impact on the environment and natural resource base, its economic vitality, and the quality of life of farmers and society as a whole. Although many farming practices, technologies, and approaches have improved one or two aspects of sustainability, they might have unintended negative effects on the other aspects of sustainability. As awareness on the importance of balancing the four sustainability goals increases, U.S. agriculture is at a pivotal point that can change the trajectory of farming toward improved sustainability by increasing understanding of the interactions and net impact of combinations of practices and approaches at the farm level and the collective actions of a number of farms on the landscape level. REFERENCES Arikan, O.A., W. Mulbry, and C. Rice. 2009. Management of antibiotic residues from agricultural sources: use of composting to reduce chlortetracycline residues in beef manure from treated animals. Journal of Hazardous Materials 164(2–3):483–489. American Farmland Trust. 2002. Farming on the edge: sprawling development threatens America’s best farmland. Washington, D.C.: Author. Andrejczak, M. 2009. Pacific ethanol units joins others in bankruptcy court. Market Watch, May 18, 2009. Aneja, V.P., W.H. Schlesinger, and J.W. Erisman. 2008. Farming pollution. Nature Geoscience 1(7):409–411. Arcury, T.A., J.G. Grzywacz, D.B. Barr, J. Tapia, H.Y. Chen, and S.A. Quandt. 2007. Pesticide urinary metabolite levels of children in eastern North Carolina farmworker households. Environmental Health Perspectives 115(8): 1254–1260. ASABE (American Society of Agricultural and Biological Engineers). 2005. Manure production and characteristics. ASAE Standards (March):20. Baker, A., and S. Zahniser. 2006. Ethanol reshapes the corn market. Amber Waves 4(2):30–35. Ball, E. 2005. Ag productivity drives output growth. Available at http://www.ers.usda.gov/AmberWaves/June05/findings/AgProductivity.htm. Accessed on August 31, 2009. Batie, S. 2008. The sustainability of U.S. cropland soils. In Perspectives on Sustainable Resources in America, R.A. Sedjo, ed. Washington, D.C.: RFF Press. Berry, W. 2004. The Unsettling of America. 3rd edition. San Francisco: Sierra Club Books. Blackburn, H.D. 2006. National animal germplasm program: challenges and opportunities for poultry genetic resources. Poultry Science 85:210–215. Bricker, S.B., C.G. Clement, D.E. Pirhalla, S.P. Orlando, and D.R.G. Farrow. 1999. National estuarine eutrophication assessment: effects of nutrient enrichment in the nation’s estuaries. Silver Spring, Md.: National Oceanic and Atmospheric Administration, National Ocean Service, Special Projects Office and the National Centers for Coastal Ocean Science. Brown, P.L., A.D. Halvorsen, F.H. Siddoway, H.F. Mayland, and M.R. Miller. 1982. Saline-seep diagnosis, control, and reclamation. Available at http://www.wsi.nrcs.usda.gov/products/W2Q/downloads/Salinity/Saline_Seeps.pdf. Accessed on February 18, 2010. Browne W.P., J.R. Skees, L.E. Swanson, P.B. Thompson, and L.J. Unnevehr. 1992. Sacred Cows and Hot Potatoes: Agrarian Myths in Agricultural Policy. Boulder, Colo.: Westview Press. California Department of Finance. 2007. Population projections by race/ethnicity for California and its coun-
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