Introduction
The 20th century's unprecedented advances in the application of biological science and engineering to agriculture have revolutionized farming. Technologies are implicitly functional, benefiting society by solving a problem or circumventing a functional constraint. Agricultural technologies include both engineering and biological inventions and discoveries, such as modifications to machinery, the physical environment or biological components of a system. Knowledge systems, such as decision support tools and management systems, are examples of cultural technologies.
The intensification of agriculture over the past 50 years has resulted in impressive yield improvements1. In the US, yields have risen steadily, with corn yields roughly tripling and wheat and soybean yields approximately doubling over the past half-century (Fig. 1a)2. Similar gains in animal production have increased egg production in chickens by 18% in the past 16 years, milk production in cows by 28% in the past 10 years, and average live broiler chicken weight by 155% in the past 80 yearsReference Strauss3.
Historical and projected trends in agriculture.
While addressing concerns of a growing world-wide population, these impressive yield gains have come at a cost to natural resourcesReference Naylor4 and the farming communityReference Archer, Dawson, Kreuter, Hendrickson and Halloran5. Capital intensive technologies required to realize these gains can favor agribusiness over family farmsReference Archer, Dawson, Kreuter, Hendrickson and Halloran5. The continued development of new technologies, at times needed to address issues introduced from adoption of previous technologies, puts farmers on a technology treadmillReference Cochrane6 that limits their flexibility in making management decisions. Globalization has increased competition and generated new problems and opportunities. Current technologies have opened a proverbial Pandora's Box of opportunities, risks and hope for future developments.
In this manuscript, we explore how the technological revolution has altered American agriculture and how it is likely to contribute to changes in future production practices. We examine the traditional development and adoption cycle, and explore new models of innovation delivery that are changing the process of technological advancement. Our premise is that as the world population and agricultural productivity move towards sustainability, agricultural problems will become more difficult to solve with strategies focused solely on increasing yield potential. Agricultural productivity will need to shift from a simplistic focus on yield per hectare to incorporate a broader, interdependent set of constraints including all inputs to the production cycle: natural resources, financial and human resourcesReference Naylor4. We explore five fundamental ways that technology has impacted farming: (1) increased intensification of production, (2) increased reliance on natural resources, particularly soil and water, and non-renewable resources, primarily fossil fuels, (3) increased production inputs and dependence on future technology, leading to a technology treadmill that limits choices, (4) increased complexity of the farming system, and (5) decreased control by producers. These trends in agriculture have led to declining support for agricultural production as fewer people are directly involved with farming; increased degradation of natural resources through contamination of soil, water and atmosphere; depletion of natural resources, particularly water and fossil fuels; and decreasing profit margins. To address the interconnected constraints facing American agriculture and ensure future advances in agricultural productivity, multidisciplinary problem solving approaches will become increasingly important.
Processes of innovation and adoption
The problems and needs of the production community drive the interdependent processes of development and adoption to bring an innovation into use. Rather than a linear event, these two processes occur in a continuous spiral, with continued adaptation and modification of a technology furthering the advancement and continuing the cycleReference Petroski7.
The traditional processes of technology development and adoption have been described as a linear or ‘Push’ systemReference Douthwaite, Keatinge and Park8, Reference Hagel and Brown9 in which the problem is identified and technology developed for delivery to the end user. This method works well during crisis conditions, such as invasive pests or diseases (e.g. Karnal–Bundt and avian flu), or for problems requiring a high input of technical expertise or capital, such as development of genetic modification techniques.
Emerging models of development and adoption rely on closer interaction between technical developers and non-technical end-users. In a ‘learning selection’ model, developers interact closely with a self-selected group of interested end-users, and use their knowledge base to refine the initial design concept to the needs of the user groupReference Douthwaite, Keatinge and Park8. As the development–adoption process continues, the initial user group becomes invested in the technology and plays a key role in the dissemination of the information and adoption of the technology by a larger user group. This model works well in the development and delivery of mechanized agricultural technology, such as harvesting equipmentReference Douthwaite, Keatinge and Park8. In the ‘Pull’ modelReference Hagel and Brown9, a platform for information exchange is established that expands the base of knowledge available to the developers and end-users by bringing together large groups of diverse individuals to solve or influence a problem. Complexity and chaos are seen as opportunities for expansion of ideas rather than as negative factors that need to be controlled. This emerging model is operating in media, global process networks and education. The ‘Pull’ model holds particular promise for the large, complex problems, ranging from social to technical, that face today's agriculture. Expansion of the knowledge base, through increased participation of people from a diversity of disciplines, has the potential to enhance the creativity applied to solve emerging agricultural production issues.
The process of adoption is driven by interactions between a broad range of external and internal factors, such as political readiness, social and political pressure and monetary constraintsReference Hendrickson, Sassenrath, Archer, Hanson and Halloran10. Farmers have a desire for increased profitability and greater lifestyle securityReference Archer, Dawson, Kreuter, Hendrickson and Halloran5, Reference Sumberg and Reece11. Competition from global markets has also facilitated adoption of new technologies as farmers recognize the need to remain competitiveReference Flora12. Innovations that reduce production risk and are relatively simple to use are most successfully adoptedReference Batz, Peters and Janssen13. In addition, farmers who have ready access to an expert are much more likely to implement new technologiesReference Sassenrath, Hanson, Hendrickson, Archer and Bohlen14.
Problems driving innovation
Fundamental limitations to agricultural production arise from edaphic, abiotic and biotic constraints of the natural environment. Water has a particular global significanceReference Watson, Zinyowera and Moss15, and limits production in many areas due to quantity and quality constraints, as well as pumping costs. The biological capacity of crops and animals also limits yield. Natural resource limitations are critical to current and future production, and future impacts of global warming and climate change are of increasing concern to farmers. Additionally, the availability and expense of fossil fuels has become a concern as they are needed both as fuel for tractors and for fertilizer production.
Social and political pressures alter the expectations from agricultureReference Archer, Dawson, Kreuter, Hendrickson and Halloran5. Changes in the social conscience moved society towards the industrial model of success based on production output. Simultaneously, growing awareness of inequities in food availability encouraged aggressive production goals to increase the worldwide per capita caloric uptakeReference Welch and Graham16. To increase production levels with a declining pool of laborers for farm work, farmers needed to do more work with fewer people17. Legislation impacts major decisions through set-aside programs or price supports and the adoption of specific technologies directly, such as the 1996 Food Quality Protection Act18. The current discussion of environmental credits versus commodity payments will further impact farmers' decisions as to which production systems to implementReference Archer, Dawson, Kreuter, Hendrickson and Halloran5, Reference Halloran and Archer19. Human resource limitations in management expertise and time further hinder productive capacity, requiring improved marketing and management skills to remain competitive.
Technological Advances
Genetic improvements
Advances in our understanding of reproductive biology and the mechanisms of inheritance enhanced our ability to make directed changes in crop and animal traits, improve yield, address environmental limitations, and overcome a host of production constraints. Genetic manipulation by selective breeding or direct molecular techniques is an established method for improving productive capacity and the regional usefulness of crops. Other technologies, such as weed and insect control and resistance to or control of diseases, increase productivity by preventing indirect competitive losses.
Hybrid maize was one of the 20th century's major scientific innovations contributing to yield improvements, and is widely cited as one of the most rapidly adopted agricultural technologies in the 20th centuryReference Brown20, Reference Tracy, Goldman, Tiefenthaler and Schaber21. In addition to the yield advantages with hybrid crops, the greater crop uniformity increased the ease of management. Prior to the introduction of hybrids, a field of maize contained a mixture of unique genotypes varying in economically important traits such as ear height, maturity and grain characteristics. This variation made mechanization of production difficult, especially harvest. Mechanized harvesting of corn coincided with the adoption of hybridsReference Myers22. Both improvements in yield and management hastened the adoption of hybrid technologies.
Though greater uniformity in the timing of plant developmental events may be desirable for timing of agricultural inputs and harvest, this uniformity renders the crops more susceptible to catastrophic losses from insects and pathogens. By compromising the seeds' natural defensive abilities by selecting for more desirable traits, producers must increasingly rely on chemical control methods and increased management for some of the functionality that the crop once provided for itself. Extensive implementation of monoculture production has increased reliance on technologies such as chemical control methods and reduced crop diversity.
Hybrids have also instrumented a substantial paradigm shift in how society views genomic property rights, and played a role in the evolution of the seed industry. With hybrid technology, farmers must buy the seed each year rather than saving seed from the previous harvest. Competitors cannot sell a company's hybrids unless they obtain the rights. Development of hybrids and subsequent genetic modifications have removed natural genetic material from public ownership and placed it in the hands of a few companiesReference Kneen23. As development and adoption of genetically altered materials increases, the production system becomes more complex. Moreover, producers increasingly lose control of their production decisions, as the management technology is genetically hard-wired in the seedReference Kneen23.
The social response to genetic technologies is most apparent in the current debate over genetically modified organisms (GMOs)Reference Benbrook24, Reference Chassy, Parrott and Roush25. While opponents of the technology accuse agribusiness of profiteering at the expense of risks to public health, the purported harms of GMOs are often ascribed to political posturing and anti-scienceReference DeGregori26 by supporters of the technology. Regardless of one's supportReference Chassy, Parrott and Roush25 or contemptReference Stabinsky and Cotter27 for the technology, it is obvious that it has had, and will continue to have, substantial social impactsReference Pardo and Calvo28.
As with plants, the natural genetic variations in animals have been used to selectively improve animal stocks. Until the mid-20th century, the formation of most modern breeds of livestock was defined by the breeders themselves and selection was strongly influenced by livestock competitions. Development of artificial insemination (AI) dramatically increased productivity, especially of dairy cowsReference Foote29. Combined academic and industrial research addressed a major constraint on genetic improvement through development of semen extenders, a method of freezing semen, and a convenient method of safely transporting frozen semen. Improved quantitation of genetic lineage has allowed managers and advisors to evaluate and benchmark their specific management strategies. Widespread dissemination of extended and frozen semen has resulted in international commerce of tens of millions of semen dosesReference Thibier and Wagner30.
Formation of farmer-owned AI cooperatives and long-and short-term experiments conducted on cooperator farms were keys to the successful adoption of AIReference Foote29. While these initial cooperatives were formed between producers, advances in AI technologies led to the consolidation of AI organizations and increased investment by privately held companiesReference Funk31.
Modern gene manipulation tools have expanded our capacity for improvements and are used in animal and aquaculture systems to identify superior traits, enhance breeding programs, facilitate disease resistance and establish, meet and verify standards. Molecular genetics can be used to improve the population through identification of genes and genetic markers associated with a desired trait, such as disease resistance, improved growth rate or meat quality. Biotechnology in animal systems can be used to do the same things currently done through traditional breeding, but more quickly, more accurately, and (or) with a different price structure, thereby changing competitive advantages among individuals, companies and countries.
In the dairy industry, improved genetic evaluations for milk production led to rapid increases in milk production and a subsequent decline in the number of cows needed to sustain production levels. Mechanization and other improvements in dairy production intensified the consolidation of dairy farms. The reduction in nationwide herd size and consolidation of dairy farms has led to a reduced genetic diversity and increased inbreeding, which may be contributing to the recently observed reduction in fertilityReference Funk31. While genetic improvements of animals have increased performance and yield, as with crops, they have been associated with (a) a loss of farms through consolidation, (b) a decline in farmer control of the production process, and (c) an increased complexity of the farming system.
Mechanization
In the US, social pressures have driven the evolution of agriculture to deliver abundant, inexpensive, readily available foods year round. The changing social conscience introduced with industrialization shifted the social expectations away from farming as a way of life towards efficiency and production outputReference Mariola32. Technological advances developed during and immediately after World War II increased mechanization and introduced chemicals to manage soil fertility and pests. Changes in commodity supportsReference Hendrickson, Sassenrath, Archer, Hanson and Halloran10 and increased social pressure to feed the world further directed production towards large-scale monoculture agricultureReference Welch and Graham16. While advances in biological and engineering technologies made large-scale monoculture production possible, changes in the social conscience made it desirable.
To address the social demands for food and expand production and improve yields, farmers needed easier, faster, less labor-intensive and more efficient means of managing crops. Mechanization of US agriculture during the 19th and 20th centuries began with the introduction of the tractor which removed much of the backbreaking toil, increased the speed, efficiency and amount of work that could be accomplished and improved worker safetyReference White and Whaples33. Throughout the industrial revolution, innovations in farm machinery have dramatically decreased labor demands and improved the efficiency and effectiveness of field operations. The fraction of the population involved in agricultural production continues to decrease. Improved harvest, storage and transportation technologies have all contributed to greater efficiency and allowed feeding a growing population without substantial increases in land devoted to production agriculture.
A major benefit of mechanization is greater efficiency during the harvest operation which minimizes yield and quality loss due to extended exposure to bad weather. Cotton (Gossypium sps., L.) has played a significant role in clothing humanity for centuries. Its technological advancement is often a leading sector indicating the level of industrialization of a country. Development of mechanical cotton harvesters substantially impacted the social and economic development of the cotton-growing regions of the USReference Holley34. Cotton harvest technology continues to play a key role in modernization efforts in other societiesReference McClintic35.
While technical limitations hampered the development of mechanical cotton harvesters, social pressures of small farms and the sharecropping system stifled its adoptionReference Lemann36. Many were fearful of the earliest mechanical pickers, envisioning the destruction of the South's sharecropping system and the loss of work for millions of peopleReference Holley and Whaples37. The major migration of 5 million people from the South for higher-paying jobs in the North between 1940 and 1960 led to a severe labor shortage17. While the initial adoption of the cotton picker was limited by concern for the prevailing socio-economic conditions at the time, a sharp decrease in available labor during and immediately after World War II became a major impetus for its acceptanceReference Holley34.
The introduction of mechanization, particularly of harvest, increased the consolidation of fields and farms. The increased size and use of machinery introduced soil problems, such as compaction, and required greater management skill. The mechanization of cotton production increased the cost of machinery and farm operating overhead. Farm size increased to justify this outlay for machinery and to support the general farm overhead. The average cotton farm in the 1940s was about 320 ha, but by the 1970s the average size had increased to 600–800 ha, a trend that continues17, 38. The harvesting operation had long been the decisive factor in land area one farm could manage, in cotton as well as other cropsReference Grimes, Kifer and Hodges39, Reference Martin and Cooke40.
Additional improvements in mechanization have been realized through a host of highly effective technologies, such as fertilization, irrigation and tillage. These improvements modified the crop environment, minimizing the natural limitations of the crop and its environment. However, this increased reliance on mechanization also contributed to a greater dependence on fossil fuels, for both fuel and fertilizer, increased consolidation of farms, increased production inputs, overuse of natural resources and greater complexity of the farming system.
Lifestyle changes in the US have led to the increased consumption of convenience foods, impacting the food supply and altering agricultural productionReference Martinez and Stewart41. This led to the development of vertically integrated production systems, particularly of animalsReference Hendrickson, Sassenrath, Archer, Hanson and Halloran10, and hastened the development of technologies supporting confinement animal production.
New barriers to production have been introduced through the intensification of animal production in confinement buildings and feedlots. Accurate identification and tracking of animals is needed to determine previous history and potential performance, and especially recognition of potential disease exposure such as bovine spongiform encephalopathy (BSE). As with monoculture crops, intensive animal production exposes animals to increased risks of some diseases, requiring changes in disease management including the increased use of antibiotics with uncertain impacts on consumers. Intensive animal production facilities also concentrate wastes which impair soil and water resources and require additional technologies to handle disposal. Moreover, the vertical integration of animal production, with its rigid top-down management and dependence on expensive animal production technologies, has left many producers frustrated from excess debt and a lack of control on their own farmsReference Sassenrath, Hanson, Hendrickson, Archer and Bohlen14.
Conservation technologies
While technologies addressing genetic improvements and mechanization are driven fundamentally by a desire to improve yield, the development of conservation production systems is driven by concerns for the environment, often resulting from problems introduced from previous technologies. Conservation practices help conserve limited soil and water resources and address production problems on areas too steep or dry for conventional tillage. Reduced tillage operations and use of cover crops protect the soil surface from erosion and ultimately increase organic matter and aggregate stability to improve the soil's water holding propertiesReference Martens42.
In addition to the environmental benefits, conservation technologies often approach agricultural production as a system. By considering the entire agro-ecosystem, the impact of production practices on the supporting natural resource base are recognized. As the knowledge of interactions within the agricultural production system grows, appreciation for the importance of conserving the natural resource base increases. Ancillary benefits to producers include savings in time and fuel from conservation tillage systems, as well as lower capital investment in powerful tractors and tillage equipmentReference Martin, Robinson, Cooke and Parvin43.
Conversely, conservation tillage has a number of potentially significant disadvantages. Tillage is an effective mechanical form of weed control that prepares the seed bed and reduces pathogens. Without mechanical weed control, herbicide use and costs will generally increase, especially during the early transition years. The introduction of herbicide-resistant crops hastened the adoption of conservation systems, as farmers had a reliable chemical method of weed control. However, this rapid and extensive adoption has increased the development of herbicide-resistant weedsReference Osteen and Livingston44. Farmers are now on a treadmill of needing new herbicide-resistant varieties to compensate for failures in the previous technology.
Increased complexity of management results from the implementation of conservation systems, as timing of operations becomes more critical. Management of cover crop residue is also a concern. Increased residue from cover crops keeps the soil wetter and cooler after planting than tilled soil, shortening the growing season. Increased residue from conservation tillage may also require changes in nitrogen management, as high levels of residue can immobilize nitrogen, limiting its availability near the seedling roots. Yield depression related to inadequate early season nitrogen may have been one of the causes for a dip in no-till use in the late 1990sReference Martens42.
Conservation technologies showed a combination of linear delivery and learning selection, with the public and private sectors providing the general outlines of the technology and farmers customizing and adapting the technology to their particular situations. Conservation tillage is adopted more rapidly by farmers with more education, larger operations, and higher incomes, and on farms with higher soil qualityReference Fuglie and Kascak45, Reference Napier, Tucker and McCarter46. Risk-averse farmers adopt conservation tillage more slowly than risk neutral farmers to avoid higher initial costs while learning the new systemReference Bosch and Pease47. Land tenure also influences adoption rates of conservation practices as cash-renters are less likely than owner-operators to adopt practices with medium term payoffsReference Sassenrath, Hanson, Hendrickson, Archer and Bohlen14, Reference Soule, Tegene and Wiebe48. This may be a key finding for the future of American agriculture, as over 40% of US farmland is leased.
Perhaps the biggest boost for adoption of conservation tillage came from government programs, starting with the Conservation Compliance provisions of the 1985 Farm Bill, and continuing through subsequent farm bills. These provisions required farmers on Highly Erodible Land (HEL) to reduce erosion significantly by using an approved conservation system to maintain benefit and program eligibility. For many farmers on HEL, conservation tillage was the only feasible management system to maintain eligibility.
With continued pressure from environmental interests, social and political concerns and increasing fiscal demands, farmers will continue to explore methods to reduce costs by eliminating field operations, provided that options exist that maintain yields and profitability. With steadily improving implements, agrichemicals, and seeds adapted to higher residue levels, increased local experience, and declining social pressures against conservation tillage, conservation tillage should continue to expand, particularly where erosion is a problem, for larger, owner-operated farms and for farmers who are not strongly risk-averse. Improved methods of weed control, particularly if they are simple, would facilitate expanded use of conservation tillage for those crops and regions that have not seen much adoption to date. Modifications to future farm bills away from commodity payments towards conservation payments will likely further hasten the adoption of conservation systems.
Conservation systems have the potential to move agricultural production systems towards environmental sustainability. Environmental concerns will continue to influence governmental programs that promote conservation tillage. Baylis et al.Reference Baylis, Feather, Padgitt and Sandretto49 reported that even a moderate increase in adoption of conservation tillage would improve water quality enough to increase downstream recreation benefits nationally by $175 million. A large increase in the use of conservation tillage may contribute $243 million nationally for recreation alone.
Information systems
Information systems are examples of technologies that were largely developed in areas other than agriculture, and have been adapted to farming. Software development and information management systems have improved the ability of the farmer to manage complex agricultural production systems, especially for record keeping and marketing of crops.
The increasing complexity in agricultural systems requires more attention to management and greater finesse in the decision making process. Increased globalization has expanded competition, requiring producers to improve their marketing skills to get the best prices for their products. While some production systems have become more vertically integratedReference Martinez and Stewart41, other producers have found ways to recapture income through diversification of farm enterprises in which the producer maintains control, or an economic interest in, value-added products beyond the farm gateReference Sassenrath, Hanson, Hendrickson, Archer and Bohlen14. Additionally, increased social and political pressures to minimize environmental impact have increased record keeping requirements and confounded production choices.
Information systems can help manage much larger amounts of information and encompass a variety of technologies. Some information technologies include automated detection systems, such as remote sensing, soil sampling systems, and yield monitors, that allow producers to gather physical information about their production system. These rely on global positioning systems to spatially record physical attributes. Other information systems are designed as management tools for record-keeping, and may incorporate a geographic information system for spatially recording physical and economic information about the system and help make management decisions. More complex information systems, such as crop models, rely on data about the system and make management decisions based on predictive estimates of system function. These tools can be simple, requiring a minimal amount of data collection and computer technology, or complex, requiring extensive data collection and computer expertise. Sophisticated technologies that offer the potential to improve crop management such as precision agricultureReference Stafford50 are often facilitated by information technologies. As the technology has advanced, potential cost benefits from implementing precision agriculture have improvedReference Martin, Hanks, Harris, Wills and Banerjee51.
The early stages of the development of information technologies fit a linear transfer of technology model, as technology was borrowed from other disciplines such as computer engineering and adapted to agriculture. Increased intensification of farms and improvements in computer and engineering technologies led to the development of precision technologies for agricultureReference Stafford50. As the technology progresses, it is evolving into a learning selection model as more end-users are becoming involved in developing or modifying existing tools to suit their needs. However, the complexity of the systems and perceived limited or negative return on investment have hampered wide-spread adoptionReference Adrian, Norwood and Mask52. The learning curve for adopting information technologies can often be prohibitively steep, though as farmers' education levels increase, their use of computer technologies increasesReference Adrian, Norwood and Mask52, Reference Batte53. Simplicity of a technology and its potential to decrease risk have been identified as prime factors in the adoption of new technologyReference Batz, Peters and Janssen13. The perceived absence of both of these factors is apparently limiting the rapid adoption of information systems in agricultural production. Adoption of technology is also age-related, as older farmers are less likely to adopt computers on-farmReference Batte53.
The most common information systems used by farmers are computers for financial and production record keeping and information gathering from the InternetReference Batte53. More complicated technologies, such as crop models and decision support tools, have slower acceptance rates. As information technologies become more user-friendly and the user base becomes more knowledgeable about the potential utility of these technologies, development and adoption of information systems into agriculture are likely to increase.
In addition to their greater complexity, decision support tools rely on the knowledge of complex issues. Many of the factors impacting complex systems will not be observed through traditional reductionist research. Rather, the emergent properties of the system will only be observed in a systems research program. Future advances in the application of information technologies to agriculture may require a greater emphasis on systems researchReference Ikerd54, Reference Aldy, Hrubovcak and Vasavada55.
Information systems expand knowledge exchange through technologies such as the Internet and enhance the breadth of expertise available for identifying problems and developing solutions. Farmers now have access to more information more quickly and from a much broader range of sources than ever before. This allows them to make more rapid decisions, such as when to buy and sell products. Information technologies offer methods of integrating the disparate pieces of the production puzzle for information gathering and decision support. As the agricultural system becomes more complex, this information will be increasingly important in guiding farmers.
Implications for Future Agronomic Technologies
Social, political and economic pressures worked in concert to shape the evolution of the current agricultural production systems in the USReference Hendrickson, Sassenrath, Archer, Hanson and Halloran10. Technological advances, often designed to address social concerns or overcome environmental limitations, further refined agriculture. While the current US agricultural systems are unquestionably highly productive, this abundance is based on an unsustainable use of natural resources and fossil fuels. Future challenges will exacerbate an already complex system and introduce new and greater problemsReference Hanson, Hendrickson and Archer56. Emerging technologies will be needed to address issues of economic and environmental sustainability, shifts in global population and consumption patterns and competition for land use.
Since technology is developed at the leading edge of our understanding, it is difficult to anticipate the impacts of that technology on the agricultural system. Since the 1930s, increases in production efficiency from technological innovations have occurred in conjunction with substantial structural changes in farming communities as fewer people are involved in agricultureReference Hendrickson, Hanson, Tanaka and Sassenrath57. In light of changing constraints to agricultural production, questions arise as to future advances in agricultural productivity, not from the standpoint of abundance, but of sustainabilityReference Naylor4. How, then, do we transition the current US production system to economically and environmentally sustainable production? While it may seem appealing, it is most likely neither possible nor desirable to discontinue technological advances.
A change in philosophical approach to address sustainability may be more important than simply changing practicesReference Ikerd54. Innovators in agriculture, including farmers, educators, researchers, businessmen, lawmakers, and so on, need to focus on more inherently multidisciplinary approaches to solve agricultural production problems. Moreover, there must be a broader focus on problem identification and resolution, incorporating societal, political and global goals of environment and nutrition together with producers' financial goals. In developing an economically and environmentally sustainable agricultural agenda, society must be willing to compromise its expectations, since current consumption levels of agricultural products, and the natural resources they require, are not sustainableReference Mayo, Knight, Clifton, Jackson, Johnstone, Furey, Lee and Pomfret58. New approaches to technology development and delivery have the potential to accommodate these needs by establishing a broad network of individuals with a diverse range of expertise, and working closely with the end users to identify goals, delineate problems and develop solutionsReference Hagel and Brown9.
Although the US has succeeded in developing an inexpensive, efficient food production and delivery system, over-consumption and lowered nutritional value have negative impacts on soil and water resources and human healthReference Blair and Sobal59. Globalization makes a variety of foods available year round, but increases hidden costs due to transportation and compromises flavor and nutritionReference Wilkins60. Food in the US is readily available and inexpensive in part because we have ignored the costs of natural resource depletion and non-renewable fossil fuel use in calculating the costs of production. While the caloric content of available food has increased worldwide, increased globalization and concentration of the food system has reduced local production of crops and limited distribution, access and future food optionsReference Koc and Dahlberg61. Exploring the linkages between food, health, agriculture and the environment requires a different philosophical approach to agricultural production than a simple focus on yieldReference Welch and Graham16, and is becoming an increasingly important component of the social environment influencing farmingReference Archer, Dawson, Kreuter, Hendrickson and Halloran5.
The current production system is not economically sustainable for farmers. Prices paid to US farmers have not kept pace with the cost of agricultural inputs (Fig. 1b)2. The unfavorable price shifts force increases in farm size, limit investment in agriculture and lead to political pressure for substantial farm programs to support agriculture and rural communitiesReference Archer, Dawson, Kreuter, Hendrickson and Halloran5.
The world's growing population and increasing income imply increased demand for agricultural goods. Contrary to Malthusian expectationsReference Ehrlich62, however, to date supply has increased faster than demand. Currently, more than four people are fed per hectare of cultivated land, with just over 20 people being supported per irrigated hectare (Fig. 1c)Reference Rosegrant, Paisner, Meijer and Witcover63. Estimates of future population growth and rates of cultivated land use indicate a slow increase in population per unit of irrigated landReference Rosegrant, Paisner, Meijer and Witcover63, Reference Rosegrant, Cai and Cline64, limiting the demand for agricultural products worldwideReference Johnson65.
The integrated worldwide outcome of all factors affecting agriculture shows a rising historical trend in food production per capita (Fig. 1d)2, which is projected to continueReference Rosegrant, Paisner, Meijer and Witcover63. Rosegrant et al.Reference Rosegrant, Paisner, Meijer and Witcover63 analyzed a number of future scenarios and found that, across a range of assumptions, agricultural supply is likely to keep pace with demand, resulting in similar or lower prices for agricultural goods out to the year 2020. While technology has helped realize this abundance, future advances will require a different mindset to better balance environmental and production goals and keep agricultural production economically viable.
Previous biological advances have come about largely from increases in the genetic potential of crops. Advances in biotechnology have expanded our ability to modify crop behavior beyond the range of conventional breeding techniques, improved quality and quantity of agricultural products, and incorporated unique value-added traits in newly-released cultivars. Future genetic advances will most likely come from value-added traits, such as neutraceutical and pharmaceuticals; addressing environmental constraints arising from agricultural intensification (soil erosion, water logging and salinity, coevolution of pests and pathogens, global climate change, loss of biological diversity, and limited water supply), and political, financial and human resource issuesReference Naylor4, Reference Trewavas66. Additional benefits from advances in genetic technologies will allow improved identification and incorporation of superior traits and increased food safety through improved testing methods.
Improvements in mechanization have increased production output with fewer people, and improved the safety of farm workers. Future advances in mechanization will have to address power requirements of agriculture and the current reliance on fossil fuels. Additional engineering advances have the potential to conserve natural resources through more accurate application, and by better matching inputs with potential output. Improvements in harvest, processing and storing can retain nutritional value and enhance societal access to products.
Conservation systems address environmental, social and political concerns, and, where implemented, have made significant gains towards remediation of environmental damage. Conservation practices will continue to evolve and redefine environmental sustainability and impacts while maintaining production capacity. Future advances in environmental sustainability will come from greater implementation of conservation technologies, increasing the scope of conservation tools and practices to reduce reliance on non-renewable resources and chemical controls, and greater use and reuse of waste products from both agriculture and society.
Information technologies have the potential to address increasingly complex management issues by providing decision support tools for farmers. Additional information technologies will allow tracking products from start to finish and remote monitoring of crops and animals. The enhanced tracking of production will also allow better knowledge of chemical use and application, and prediction of potential environmental impacts. Marketing tools and internet access will assist producers in the global marketing of products.
On a larger scale, our definition of agriculture may change. Agriculture can be defined as the process of using natural resources (sunlight, air, water and soil) to produce a consumable product (e.g. food, fuel and fiber), while maintaining sufficient resources for the next generation. This definition could include alternative production systems such as wind turbine farmsReference Donavan67, which do not involve cultivation of the soil but do tie up a valuable natural resource (land) in the production of a consumable item (power). Similarly, ecosystem services, such as the buying and selling of carbon credits, are potential agricultural productsReference Bricklemyer, Miller, Turk, Paustian, Keck and Nielsen68. As energy constraints and ecosystem services continue to escalate in importance, the management of the land for these purposes may surpass our current limited view of agricultural products.
Future production systems will need to be flexible to respond to rapid changes in climate and uncertainties in global markets from shifts in politics, production and population. In addition to addressing growing environmental concerns, sustainable farming systems will need to address energy concerns required for both agricultural production and as potential agricultural products.
An agricultural production system has been suggested that allows for dynamic responses to external pressuresReference Hendrickson, Hanson, Tanaka and Sassenrath57. This dynamic management philosophy coupled with multiple cropping enterprises allows farmers to incorporate changes in their production system in response to changing needs. A dynamic system would be able to accommodate the increasingly complex factors influencing farmers today and reduce risks of production. Integrated farming systems allow producers to optimize an array of factors, including environmental and financial, rather than simply focusing on yield alone. By carefully examining current production systems and the influences that have shaped them, we can develop future technologies that will address sustainability with the needs of farmers, society and the environment in mind.
