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Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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PART ONE

Overview

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×
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Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

1

The U.S. Department of Agriculture Commitment to Sustainable Agriculture

Charles E. Hess

Significant progress has been made in the past 5 years in the acceptance of the concept of sustainable agriculture. The U.S. Department of Agriculture (USDA) low-input sustainable agriculture (LISA) programs, the Leopold Center at Iowa State University (Ames), a long-term ecological research program at Michigan State University (East Lansing), and a state-wide sustainable agriculture program in California are examples. Michael Jacobson, executive director of the Center for Science in the Public Interest, recognized one aspect of progress when he said, “Even USDA is uttering the ‘O' word [organic] and not choking.”

Overall, today's agriculture is being challenged to operate in an environmentally responsible fashion while at the same time continuing to produce abundant supplies of food and fiber both economically and profitably. The scientific community is responding positively and assertively to the challenge.

There is increasing interest in the development and adoption of sustainable land use systems for two very basic reasons: (1) a need to bring about fundamental improvements in the global environment, and (2) an everexpanding need to provide economically produced food and fiber for a growing world population.

Through technology, the United States has developed an efficient, highly productive food and fiber system that is the envy of the world. Of all the people in the world, consumers in the United States currently spend the lowest percentage of their incomes on food—an incredible 11.8 percent. It is now recognized, however, that current technology has had some costs that were not fully anticipated at the time of its introduction. Scientists are

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

looking more closely at its possible social, environmental, and health impacts. Clearly, the issues—both perceived and real—that are raised by current technology must be addressed.

THE USDA APPROACH TO SUSTAINABLE AGRICULTURE

The term sustainable agriculture means different things to different people. The term itself is not important. What is important is that farmers around the country are closing their conventional farming cookbooks and carefully crafting new recipes for what might be called “smart and considerate farming. ” Rather than providing yet another definition, this chapter provides a look at the approach used at USDA.

It is the department's responsibility to provide farmers with a range of options that can best fit their economic and environmental situations. The choices range from the optimal use of fertilizers, pesticides, and other off-farm purchases in conjunction with the best management practices, to operations that actively seek to minimize their off-farm purchases and emphasize crop rotation, integration of livestock and crop production, and mechanical or biological weed control. The thing that they have in common is integrated resource management—a systems management approach that looks at the farm as a whole.

To some, this seems a return to the 1930s and “low-tech” production methods. This is not at all the basis of sustainable agriculture, however. It does not mean a return to hoes, hard labor, and low output.

Low input is not an exactly appropriate term because it carries the wrong connotation, that something can be achieved for nothing. In fact, the preferred designation is sustainable agriculture. This means the use of the very best technology in a balanced, well-managed, and environmentally responsible system. It relies on skilled management, scientific know-how, and on-farm resources.

It should be stressed again that the emphasis is not to eliminate the use of important chemicals and fertilizers. In many instances, such chemicals and fertilizers are absolutely necessary to the farmer. The emphasis is, however, to seek ways to reduce their use and increase their effectiveness to improve and maintain environmental and economic sustainability.

The appropriate measure of a system's productivity and efficiency is not how much it produces but, rather, the relative value of what it produces compared with what went into producing it. Environmental impacts must now be included in the cost-benefit equation; this has not always been considered. Contributions will be needed from all the agricultural sciences to develop sustainability models with sound management practices and techniques for food and fiber production systems.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×
The Road Ahead

It must be made absolutely clear that those involved in the U.S. agriculture system care about the environment. It is one of USDA 's top priorities, and this is certainly evident in the proposals in the 1990 farm bill and the 1991 federal budget (both of which are discussed below).

Agriculture has always tried to be a careful steward of the nation 's land and water resources, but that effort is now receiving renewed emphasis. For example, an excellent summary of data, case studies, and recommendations was presented in Alternative Agriculture (National Research Council, 1989a), which has received a great deal of attention.

Since its publication, many people have commended the National Research Council for producing such a comprehensive assessment at such a critical time. Other readers, however, say that it overstates the economic feasibility and the benefits of adopting alternative agriculture practices.

The principles laid out in that report are well worth thoughtful study and can point the way to change. A recent issue of Chemical and Engineering News (March 5, 1990) contains a good analysis of the issues involved, and the Board on Agriculture of the National Research Council will soon provide a response to some of the comments that Alternative Agriculture has generated.

In fact, some of the reactions miss the point of that report. It was never intended to prove that one kind of agriculture is superior to another but, rather, to help provide an understanding of the kinds of agriculture systems being used on U.S. farms and ranches and to encourage research not only to determine the most environmentally and economically beneficial kinds of farming but to guide development as well. The current scarcity of hard evidence on either side of the issue can only invite unfounded and unhelpful assertions.

The Need for Hard Data

There must be an effort to gain more hard data so that informed decisions can be made based on science rather than on emotion.

It is human nature to want to know everything without having to wait for it. People want to know immediately what does and does not work and why. These kinds of questions take time to answer, and time is needed to gather the evidence that will eventually lead to conclusions.

CONSTRUCTIVE APPROACHES THAT ARE UNDER WAY

The following are six concrete examples of current research.

  • Under the President's Initiative on Water Quality, research will help to provide a better sense of real versus perceived progress on the issue of water quality. This initiative will determine what agricultural practices

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

adversely affect water quality and then develop alternatives to them. The Cooperative Extension Service and the Soil Conservation Service will extend the existing knowledge of the best management practices.

  • On February 9, 1990, USDA announced the establishment of eight water quality demonstration projects to show new ways to minimize the effects of agricultural nutrients and pesticides on water quality. The Soil Conservation Service and Extension Service will provide joint leadership for the on-farm demonstration projects. Five USDA agencies have committed $3.3 million to the projects in 1990. The projects are located in California, Florida, Maryland, Minnesota, Nebraska, North Carolina, Texas, and Wisconsin.

  • In the 1990 field season, the Agricultural Stabilization and Conservation Service will test a cost-sharing program for reducing chemical use. The trial program is designed to encourage the adoption of integrated pest and fertilizer management practices. It will be limited to 20 farms in each of five counties per state in all 50 states. Participants must enroll at least 40 acres of small grains, forage, hay, or row crops and follow a written integrated crop management plan that seeks to reduce pesticide or fertilizer use by at least 20 percent.

  • Research in integrated pest management will also be continued. Integrated pest management is the study of biological controls and management practices that aid in the more precise use of pesticides and in judicious reductions in the amounts that are used. The goal is to avoid adverse effects on the environment and beneficial organisms. Yet, at the same time, care must be taken so that, in the enthusiasm to remove toxic compounds, conditions are not created in which naturally occurring toxic substances (such as aflatoxins) are able to increase.

  • In July 1989, R. Dean Plowman, administrator of USDA's Agricultural Research Service, and I participated in the dedication of a new $11.9 million soil tilth laboratory on the Iowa State University campus. This laboratory will study the effects of a variety of agricultural practices on soil structure, organic matter, microorganisms, and movement of nutrients.

  • The Alternative Farming Systems Information Center at the National Agricultural Library is another way that the transfer of knowledge is being increased. As part of the team working with sustainable agriculture, this information center focuses human expertise on the specialized subject area of sustainable agriculture. This center inventories and coordinates data from many sources and plays an important role in meeting the information needs of researchers and producers.

The Roles of Universities and Farmers

Universities will play a vital role in the future of sustainable agriculture.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

In the endeavor to create management systems that combine knowledge from a variety of areas, universities will want to create internal mechanisms to facilitate multidisciplinary approaches to research. It takes cooperative interactions among members of many disciplines for the development of stable systems.

The widespread awareness of the need for economical and environmentally sound ways of farming has not always been matched by the availability of reliable and practical information on what, in fact, can be done. Innovative farmers and researchers have generated considerable new information, but it has not always been shared with and tested by others to the extent that it should. Extension certainly has an historic and very current role in meeting this need.

A group called the Practical Farmers of Iowa (PFI) has as its goal “profitable and environmentally sound farming—pure and simple. It's got to sustain the land, the soil, the people, the communities, and the pocket-book.” This group places strong emphasis on action. Its members are involved in a number of demonstration projects that pair customary practices with alternative methods.

For instance, ridge-till farmers have compared chemical weed control with nonchemical weed control in soybean and corn demonstration projects. In 11 soybean field trials in 1989, participating PFI farmers applied no herbicides and substituted nonchemical weed control such as cultivation. They saved an average of $11.12 an acre on cultivation and labor costs as well as on the cost of the herbicides, which had already been reduced to a small, economical level. In five corn crop trials that same year, PFI farmers saved $7.00 an acre by using little or no herbicides. Yields were not affected in either case.

New ways of sharing such information must continue to be examined. Every ounce of careful management and efficient technology that can be mustered is needed to continue to maintain competitiveness in a tough global marketplace and, at the same time, to have an environmentally sensitive agriculture system.

THE NEED FOR A PROACTIVE EFFORT

It is essential that policymakers, researchers, and farmers join together to take an assertive, proactive approach in dealing with environmental issues. To say that there are no problems or that public concern is completely the product of misinformation is not a productive approach, neither for the future of agriculture nor for the restoration of public confidence.

The public is growing more and more concerned about the impact of agriculture on the environment, particularly its potential effect on water quality. There are recent data that give some credence to that fear. A U.S.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

Geological Survey report (1989) showed that in a sampling of surface water in 10 midwestern states, 90 percent of the samples showed the presence of some agricultural chemicals.

The issue is not limited to the United States. In England, there are suits pending against water companies citing the high levels of nitrogen in drinking water, and legislation is being proposed that would regulate the amount of fertilizer an English farmer can use. The legislation proposes that the amount be based on the nitrate content of the region's well water.

If such restrictive legislation is to be avoided in the United States, a positive response to these issues must be made. It is time to be proactive rather than defensive. To do otherwise is to invite legislation and regulation that may remove farmers' decision-making powers and constrain their flexibility in adapting management practices that best fit each farming situation.

LEGISLATIVE AND FUNDING INITIATIVES
Farm Bill

Emerging environmental concerns were strongly reflected in the Food Security Act of 1985. I predict that they will be even more strongly present in the current debates over farm legislation. The proposals of the farm bill should be mentioned here because one of its three basic goals is to deal with environmental concerns. The administration is seeking an assertive role in shaping the nation's sustainable agriculture policy in the years to come. The 1990 farm bill will go far in this direction.

The bill proposes the enhancement of resource stewardship of U.S. farmers by giving them greater flexibility in their planting, crop use, crop rotation, and marketing; incentives to change their resource use in environmentally sensitive areas; and lastly, greater research and technical assistance—especially in farming in an environmentally aware way.

In the 1990 farm bill, the administration encourages changes in commodity programs to ensure that the farmers who participate in those programs will not be penalized for adopting sustainable agriculture practices. Currently, commodity programs reward farmers for growing as much of the program crop as they can on their eligible base acres. They would lose that base, and, therefore, future price support payments, if they used it to grow rotation crops, even though those crops could increase environmental and economic sustainability. The administration 's flexibility proposals would allow farmers to incorporate rotation crops without having to make that sacrifice.

Request for LISA Funding

In addition, the administration has requested $4.45 million for USDA 's

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

LISA research and education program in 1991. Furthermore, if Congress funds the proposed $100 million Initiative for Research on Agriculture, Food, and the Environment (see National Research Council, 1989b), another $1 million would be expected to be added to USDA's support for sustainable agriculture research.

LISA is highly favored by some because it provides opportunities for users of the research to have direct input into the decision-making process of selecting the projects that should be funded. Unfortunately, it has sometimes engendered skepticism as well as enthusiastic support —in part, because it differs from traditional research and education. For example, some people are suspicious of the results of studies that put farmers and others in the middle of the research and education process.

The purpose of USDA's LISA program is to help develop and disseminate to farmers practical, reliable information on sustainable farming practices. Now in its third year, the program has supported up to 90 projects ranging from experimental research to the development of educational materials. Most of the projects reviewed in this volume have been funded partially by the LISA program.

The benefits of this effort include more than information for farmers. The program is a catalyst. It is helping to stimulate sustainable agriculture research and education in many universities and other research organizations.

The LISA program is just a start, however. For one thing, it is currently limited to farm-level research and education. As noted by the National Research Council (1989b), very little research is being done on what implications the adoption of sustainable agriculture might have for the structure of agriculture, environmental quality, and rural communities, as well as for national and global food production.

This is not to say that people should ignore the question: How can the world have a clean environment and enough to eat? The pervasive negativism is that the world cannot have both and, therefore, that LISA is a false hope. Regrettably, that conclusion overlooks the other side of the equation, namely, what will be the outcome for future generations if continued reliance is placed on highly specialized, capital-intensive, chemical-intensive ways of farming? Thoughtful research is needed on this fundamental issue.

Commitment to Research

The ability to offer the farmer a broad range of practices and to tap the full potential of technology depends on a reservoir of knowledge in the basic sciences essential to agriculture. Fortunately, Secretary of Agriculture Clayton Yeutter has a deep appreciation for the role of research, and

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

President Bush has indicated that “investing in the future for a better America” is one of his major commitments.

This commitment was obvious when the president presented his budget to the Congress. He announced a $100 million Initiative for Research on Agriculture, Food and the Environment, with $50 million to be added annually in the subsequent years to reach at least $300 million, and possibly $500 million. This USDA initiative is based on the National Research Council report Investing in Agriculture: A Proposal to Strengthen the Agricultural, Food, and Environmental System (National Research Council, 1989b).

The president has proposed the following levels of funding for the first year in four major areas: plant systems, $50 million; animal systems, $30 million; natural resources and the environment, $15 million; and nutrition, food quality, and health, $5 million. The $15 million for natural resources and the environment does not seem like a significant investment, but nearly one-third of the USDA science and education budget of $1.3 billion is related to the environment.

Also, other areas in the budget are directly related to the goal of a sustainable agriculture system. For example, $15 million is proposed for the plant genome study. The goal is to determine those genes that regulate agriculturally important traits, such as disease and insect resistance.

There is also a department-wide water quality initiative with proposed funding of $207 million (an increase of $52 million) and a global change initiative with funding of $47.4 million (up from $21.2 million in 1990).

The first challenge was to get the initiative into the budget. Now, perhaps an even tougher challenge is to get it through the Congress. This is where the administration needs help and support. In addition, the Office of Management and Budget is watching carefully to see whether the administration can get the initiative passed by the Congress unimpaired by ear-marking of funds for special interest purposes. It is clearly in the best interest of everyone to resist the urge to carve up the initiative. It would be killing the goose that laid the golden egg.

CONCLUSION

The quest for agricultural sustainability in the United States and abroad bears more than a casual resemblance to the astonishing events that have been taking place in Eastern Europe, the Soviet Union, and elsewhere around the world. Both phenomena have caught some by surprise but have captured the imagination of everyone.

The similarities do not stop there. The pursuit of an environmentally and economically sustainable agriculture system, no less than the drive for freedom, involves a deep questioning of the status quo and an intense commit-

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

ment to help build a better world in the future. Both the search for sustainability and the parting of the Iron Curtain have been brewing for decades, and they are now bursting forth.

I applaud the participants of the workshop on which this volume is based for making an effort to tell others about the important work that is being done and to join in learning about the information provided by this research.

Agriculture in the United States is facing major challenges, some of which may appear to be in conflict. On one hand, agriculture needs to be highly efficient and internationally competitive in order to be economically viable. On the other hand, it needs a system of production that is environmentally sensitive and sustainable and whose products are viewed as safe. Both goals are achievable.

Sustainable agriculture is a direction that makes remarkable sense for farmers and for the rest of U.S. society. It is a direction that must be faced with a spirit of openness and willingness to change for the better.

REFERENCES

National Research Council. 1989a. Alternative Agriculture. Washington, D.C.: National Academy Press.

National Research Council. 1989b. Investing in Research: A Proposal to Strengthen the Agricultural, Food, and Environmental System. Washington, D.C.: National Academy Press.

U.S. Geological Survey. 1989. Reconnaissance for triazine herbicides in surface waters in agricultural areas of the upper midwestern United States. October 26. Unpublished.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

2

Background and Status of the Low-Input Sustainable Agriculture Program

Neill Schaller

The roots of the low-input sustainable agriculture (LISA) program go far back in time. It is the product of growing concerns of the public and farmers over unforseen high costs of conventional agriculture. Indeed, the highly specialized, capital-intensive, and chemical-intensive conventional farming methods, while boosting farm output to higher and higher levels, have had a myriad of adverse side effects on natural resources, environmental quality, human health, and food quality and safety.

LISA is but one of several names used to describe a form of agriculture that will not only be productive and profitable for generations to come but will also conserve resources, protect the environment, and enhance the health and safety of the citizenry. Other versions of the same ideal or different paths to it, are known by names such as organic, regenerative, biological, ecological, biodynamic, sustainable, low-input, reduced-input, and alternative agriculture.

BACKGROUND

“Low input” was added to LISA's name after the LISA program was first authorized to give more meaning to the rather general connotation of sustainability and to head off a possible misinterpretation that the real purpose of the program was eventually to eliminate the use of all purchased agricultural chemicals on farms and ranches as an end in itself. Low input had the advantage that it could include, but not be limited to, the chemical-free path to sustainability. The relevant question implied here is which path is the

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

most environmentally and economically sustainable, not just which path allows farmers to use fewer chemicals.

A discussion of LISA might not have occurred if it were not for important turning points in the support for agricultural sustainability. One such turning point was the farm financial crisis of the 1980s. It has long been known that conventional farming might not be environmentally sustainable. It took the financial tragedy that struck farm families early in the 1980s, however, which was the result of declining exports of U.S. farm products and plunging farmland values, to show that U.S. agriculture might be economically unsustainable as well.

Farmers who survived that economic crisis saw the urgency of farming in ways that would lower production costs and debts. Their discovery helps to explain why so much of the search for a more sustainable agriculture system has focused on reducing the use of purchased chemical fertilizers and pesticides. Not only were those inputs known to be potentially harmful to the environment, but farmers' extreme dependence on them has also been seen as weakening agriculture's economic sustainability.

Another development fostering interest in agricultural sustainability has been the growing realization among environmentalists that (1) environmentally sound farming practices must be profitable if farmers are going to adopt them, and (2) it might not always be essential —or even sustainable—to try to eliminate all synthetic chemicals from farming practices, as was assumed by some of the environmentally concerned critics of conventional agriculture.

LEGISLATION

Despite the important developments described above, in the early 1980s the U.S. Congress failed to pass legislation supporting sustainable agriculture research and education. Two reasons for this stand out. First, the initial attempts emphasized or were identified with organic farming, which lacked wide support. Some in the agriculture community saw organic farming only as a way to meet a special market niche. Most considered it, incorrectly, as a “cause” rather than as an alternative that had the potential to equal the productivity and profitability of conventional agriculture.

Another possible reason for failure to enact legislation was that early proposals supporting sustainable farming research and education included the establishment of new centers or procedures that departed from and even threatened the traditional structure and practices of the land-grant system and the U.S. Department of Agriculture (USDA).

Because the reasons for interest in a more sustainable agriculture system persisted, however, it was only a matter of time before supportive policies would be enacted (see Table 2-1). That happened in 1985 with passage of

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

TABLE 2.1 LISA Program History

 

Fiscal Year

Event

1985

1986

1987

1988

1989

1990

1991

Congress

Legislation

Food Security Act of 1985 authorizes program

       

To be reauthorized in farm bill

 

Appropriation

None

None

None

$3.9 million

$4.45 million

$4.45 million

To be decided

U.S. Department of Agriculture

Policy and programs

     

Starts LISA program

 

Supports sustainable agriculture

 

Funding recommended

None

None

None

None

None

None

$4.45 million

Number of full proposals reviewed

     

371

318

161

 

Number of LISA projects funded (%)

     

49(13)

56(18)

45(28)

 
Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

the Food Security Act (P.L. 99-198), which authorized what is now called the LISA research and education program.

The LISA program might not be recognized by the name of the authorizing section, “Agricultural Productivity Research,” Subtitle C of Title XIV on research and education (U.S. Government Printing Office, 1985). Many members of Congress and the agricultural community were, and still are, more comfortable with the term productivity than with the term LISA.

Subtitle C discussed farmers' need for sound information on alternative production systems that would not only enhance productivity but also reduce soil erosion, conserve energy, and protect the environment. It referred indirectly to the negative side effects of farming practices that rely heavily on purchased chemicals and other inputs. It called for an inventory of studies and told USDA to conduct research projects on alternative farming systems. Farmers, it said, should be involved in those studies, to be sure that the results would be useful to them. The research should also be open to people from all interested universities and private organizations.

The LISA program remained on the drawing board through 1986 and 1987. That was because Congress did not appropriate funds to support a new program, and USDA chose not to redirect existing research funds to get one started. In response to the 1985 act, however, USDA formed a task force on alternative farming systems and began to inventory existing research.

The launching of the LISA program finally came in January 1988, after Congress passed an agriculture appropriations bill for 1988 with funds earmarked for such a program.

The House Appropriations Committee report introduced the words low-input farming. It said, “The term ‘low-input' is used to describe the implementation of alternative systems to lower costs of production” (U.S. Congress, House, 1988). The report then discussed the low-input research that was under way and the fact that the National Agricultural Library had established an Alternative Farming Systems Information Center. The committee recommended $2.6 million for low-input farming research and education, including $1 million for research, $1.5 million for extension education, and $100,000 for the National Agricultural Library.

The Senate committee was more generous. It recommended $9 million, of which $2.1 million was to be used to fund a companion program known as ATTRA that supported appropriate technology transfer for rural areas. The Senate language used reduced input instead of low-input. It said, “A growing number of farmers are now looking for reliable information on reduced input farming systems. These farmers are interested in learning how alternative farming methods can be used to reduce production costs and control soil erosion and the pollution of underground water supplies caused, in part, by heavy fertilization, pesticide use, and monocultural cropping systems” (U.S. Congress, Senate, 1988).

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

When the House and Senate appropriations committees ironed out their differences, the result was a $3.9 million budget for a LISA competitive grants program, including $100,000 for the National Agricultural Library's information center. Instead of sending separate funds to USDA research and extension agencies, the conferees agreed that the program should be administered through USDA's Cooperative State Research Service (CSRS), with clear instructions that CSRS involve extension.

LISA PROGRAM ENACTMENT

Immediately after the bill was signed into law in late December 1987, the process of designing the LISA program began in earnest under the direction of Paul O'Connell, CSRS deputy administrator. Many of the participants at the workshop on which this volume is based and others associated with universities and private organizations played key roles in that process. The USDA's Alternative Farming Systems task force, which was elevated to a USDA subcommittee, also helped. It drafted a departmental memorandum that defined and established support for research and education on alternative farming systems. The draft became an official policy statement that was issued by then Secretary Richard Lyng in January 1988 (U.S. Department of Agriculture, 1988).

The decision was made to invite, review, and approve LISA project proposals mainly at the regional level. To do that, host institutions were selected in each of the four U.S. regions: the University of Vermont, Burlington (Northeast); the University of Georgia, Athens (South); the University of Nebraska, Lincoln (North Central); and the University of California, Oakland (West).

Coordinators were named to guide the program in each region. The current coordinators are Neil Pelsue, Jr. (Northeast), Charles Laughlin (South), Steven Waller (North Central), and David Schlegel (West).

Patrick Madden, who was then on leave from Pennsylvania State University, worked closely with Paul O'Connell (USDA) to develop program guidelines as well as criteria and procedures for inviting, reviewing, and approving LISA project proposals. Technical committees were established in each region, along with a smaller administrative council to act as a regional board of directors and decision-making body.

Each region was given the same amount of money, after setting aside limited funding to support conferences and other activities at the national level. An example is the Farm Decision Support System, a computer-assisted system to help farmers choose their best farming options. This is described by its designer, John Ikerd of the University of Missouri, Columbia, in Appendix A of this volume.

The LISA program was well under way by the middle of the summer of

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

1988. The early start encouraged the Congress to increase the program 's budget to $4.45 million in 1989 and to keep the funding at that level in 1990. Meanwhile, the administration, which did not recommend funding for LISA in 1988, 1989, or 1990, has included a request for $4.45 million in its 1991 budget proposals, which, as of this writing, are being debated in the Congress. In addition, Charles Hess, Assistant Secretary for Science and Education (see the chapter “The U.S. Department of Agriculture Commitment to Sustainable Agriculture, ” this volume), points out that if Congress appropriates the $100 million requested by the administration for the USDA's proposed Initiative for Research on Agriculture, Food, and the Enviornment, $1 million of the new funding would be added to the funding available for sustainable agriculture research.

LISA RESEARCH AND EDUCATION

Ongoing food and agriculture research and LISA research are not the same things, but they need each other. LISA research is applied research on alternative low-input sustainable agriculture practices and their feasibility. LISA projects deal with, or are at least oriented to the concept of, a total farm system. In contrast, much of the ongoing production-related research is focused on single practices or relationships involved in farming—for example, on the effects of different levels of a single input or technology on the yield of a particular crop. Often, the latter research can make an important contribution to the development and testing of knowledge about sustainable agriculture practices. The results of LISA research, in turn, can increase the payoff from ongoing research by identifying the component problems that it should address.

The following is a breakdown of the LISA program's record (Madden et al., 1990):

  • In the first year (1988), a total of 371 project proposals were received. Of those, 49 (13 percent) were selected to receive funding. Other competitive grant research programs administered by USDA now fund an average of 20 percent of the proposals received. The 20 percent figure is also fairly typical for other federal and nonprofit research organizations.

  • In an effort to reduce the disappointment level associated with this very low acceptance rate, the Western region LISA program called for abbreviated preproposals in 1989. Of a total of 143 preproposals submitted, 32 were selected for development of full proposals. Of 30 proposals received and reviewed, 11 were funded.

  • For the United States as a whole, 318 full proposals were evaluated in 1989; 56 (18 percent) were approved, including 27 renewal projects that were first funded in 1988 for which continued support was requested and 29 new projects.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×
  • In 1990, the Southern and North Central regions called for abbreviated preproposals. A total of 438 were submitted; 91 of these preproposals were selected for development into full proposals, and 86 proposals were submitted. Twenty-one of these were funded: 12 in the Southern region (including 11 new projects) and 9 in the North Central region (5 new projects).

  • In the Northeast region, 67 proposals were reviewed and 16 were funded, including 7 new projects.

  • The Western region did not invite new proposals in 1990. They had agreed in 1989 to continue supporting previously approved projects, if their progress was satisfactory, leaving insufficient funds for new projects.

  • Therefore, 28 percent of the full proposals reviewed in 1990 were funded.

Without a higher level of funding, the LISA program will be able to support either a limited number of proposals for 1 or 2 years or an even smaller number of proposals for several years. Neither choice is satisfactory. The need to provide support for more than 1 or 2 years is especially critical for projects dealing with the feasibility of expanded rotations and other practice changes that extend over many years. The need to assist more of the prospective LISA research teams that are interested in and able to shed light on low-input sustainable practices is just as compelling. Moreover, a relatively high proportion of LISA proposals is not likely to find support elsewhere.

QUESTIONS AND ANSWERS ABOUT THE LISA PROGRAM

The following are some of the questions people ask about the LISA program and the current answers:

Does every state have a LISA project?

Almost. Only four states cannot claim a principal coordinator or major participant in a LISA-supported project.

To what extent are farmers really participating in the program?

About 1,183 farmers are now involved as participants in LISA-funded projects. Of these, 521 have generated ideas for projects, and 155 have provided land for experimentation and other inputs (Table 2-2). Of a total of 74 people who are members of the regional technical committess, 19 are farmers. Eight farmers are serving on the regional administrative councils, which have a total of 39 members.

How important is the participation of private organizations?

Nineteen of the projects now supported have principal participants who are with private organizations. In the 2-year period from 1988 to 1989, some 20 institutes, associations, and other private organizations have added

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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TABLE 2-2 Participation of Farmers in LISA Projects in Each Region and the United States

 

Number of Farmers Serving This Role (by region)

Farmers' Roles

Northeast

Central

North Southern

Western

United States*

Provide land for

Replicated experiments

50

42

33

30

155

Unreplicated studies

98

33

45

151

327

Demonstration plots

44

44

38

27

153

Generate ideas

for project

118

129

67

202

521

Help to manage project

67

97

50

45

259

Evaluate project

138

110

77

167

497

Provide information on

Yields

188

169

49

358

767

Costs and returns

133

158

49

253

596

Labor requirements

85

74

41

320

523

Presenter at conference

27

60

38

96

221

Total, one or more roles

217

223

86

652

1,183

* Includes one national project with five farmers (the Farm Decision Support System).

SOURCE: Survey of LISA project coordinators, conducted by MaddenAssociates Inc., Glendale, Calif., May 1990.

over $900,000 in matching funds to the $750,000 in funding provided to them by the program.

How much support are LISA projects actually receiving from the program?

The average amount of support per project per year is $40,000. The project awarded the largest support so far received $220,000 for 2 years. At the other extreme, a project to develop educational displays requested and received $4,000.

The LISA program has a matching fund requirement. How much have participating organizations contributed to LISA projects?

In 1988, they added $3.6 million. Matching funds were $3 million in 1989 and $5.1 million in 1990. Each year private organizations contribute over $500,000 in matching resources as participants in LISA projects.

What proportion of LISA projects deals primarily with organic farming?

So far, only about 4 percent.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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THE FUTURE

The future status of the LISA program rests to a great extent on the outcome of the 1990 farm bill debate, which was under way at the time of this writing, as well as on annual appropriations. The current authorization ends with expiration of the Food Security Act of 1985. Different reauthorization language has been suggested by various interest groups and USDA.

Several versions now label the proposed legislation, “Sustainable Agriculture Research and Education,” in part because the term low-input continues to cause confusion and misunderstanding. Most of the proposed language reaffirms the purpose of the current LISA program and its structure and procedures. Some extend the program's scope—for example, to support research on the social and economic implications of widespread adoption of LISA, in addition to providing farmers with practical information on sustainable agriculture practices. Several versions would authorize an increased funding level from $40 million to $50 million.

The year 1990 is surely critical to the life of LISA. From all indications, however, sustainable agriculture research and education could be well on the way to becoming mainstream agriculture research and education.

AUTHOR'S NOTE: When this chapter was written, the 1990 farm bill debate had just begun, and fiscal 1991 federal appropriations had not been passed. During 1990 and early 1991, more LISA projects were funded, and more farmers became involved in the program. Readers who are interested in updating the information in this chapter may obtain the following reports from the LISA Program, Cooperative State Research Service, U.S. Department of Agriculture, Room 342, Aerospace Building, 14th and Independence Avenue, SW, Washington, DC 20250-2200 (202/401-4640):

  • USDA. 1991. 1991 Annual progress report. Sustainable Agriculture Research and Education Program, Cooperative State Research Service, USDA. 20 pp.

  • Madden Associates, Inc. 1990. Farmers participating in LISA projects, directory 1988 to 1990. Low-Input Sustainable Agriculture Research and Education Program, Cooperative State Research Service, USDA. 50 pp.

REFERENCES

Madden, J. P., J. A. De Shazer, F. R. Magdoff, N. Pelsue, Jr., C. W. Laughlin, and D. E. Schlegel. 1990. Low-Input Sustainable Agriculture Research and Education Projects Funded in 1988 and 1989. LISA 88-90. Washington, D.C.: Cooperative State Research Service, U.S. Department of Agriculture.

U.S. Congress, House of Representatives. 1988. House Agricultural Appropriations Committee Report. Washington, D.C.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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U.S. Congress, Senate. 1988. Senate Agricultural Appropriations Committee Report. Washington, D.C.

U.S. Department of Agriculture. 1988. Office of the Secretary. Alternative Farming Systems. Secretary's Memorandum 9600-1. January 19. Washington, D.C.: U.S. Department of Agriculture.

U.S. Government Printing Office. 1985. Food Security Act of 1985. P.L. 99-198. Washington, D.C.: U.S. Government Printing Office.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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3

Challenges and Rewards of Sustainable Agriculture Research and Education

R. James Cook

For the past 50 or more years, the emphasis in agricultural research and education has been on improving crop plants and livestock as biological resources. This emphasis must continue. There is another equally great biological resource, however, that has the potential to increase both the productivity and sustainability of agriculture that remains largely untapped. This biological resource is external (or sometimes internal) to, while interacting with, crops and livestock, and it is represented by a nearly limitless variety of biological systems, interactions, and natural cycles on farms. The farming systems identified in the report Alternative Agriculture (National Research Council, 1989a) have as their common thread the goal to make greater use of these biological resources.

John Pesek, who was the chairman of the committee that produced the report Alternative Agriculture, made the central theme of the report very clear in remarks in Washington, D.C., on the day the report was released and in the following remarks he made to the International Fertilizer Industry Association (Pesek, 1989, p. 6).

Alternative farming practices are far more than conventional agriculture with lowered inputs of fertilizer and pesticides. They are an array of options that emphasize management and take advantage of biological relationships that occur naturally on the farm. The objective is to enhance and sustain rather than to reduce and simplify these relationships—to make them relevant to the production system rather than irrelevant; not to mask them with excesses. No present technologies have been ruled out—the intensity and, in some cases, the frequency of their use is moderated.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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This idea is not new. Charles Benbrook, executive director of the Board on Agriculture, has brought together some quotes from the writings of Aldo Leopold, after whom the recently opened and dedicated Leopold Center for Sustainable Agriculture is named at Iowa State University in Ames. To set the stage for why better use should be made of natural biological interactions and cycles on the farm, one of these quotes is appropriate here (Benbrook, 1990, p. 23):

. Few educated people realize that the marvelous advances in technique made during recent decades are improvements in the pump, rather than the well. Acre for acre, they have barely sufficed to offset the sinking level of fertility. In all of these cleavages, we see repeated the same basic paradoxes: man the conqueror versus man the biotic citizen; science the sharpener versus science the searchlight on his universe; land the slave and servant versus land the collective organism.

Almost 70 years ago, Carl Hartley of the Bureau of Plant Industry, U.S. Department of Agriculture (USDA), recognized the power of what he termed the biological factor in producing pine seedlings in nurseries for reforestation (Hartley, 1921). The nursery soils were treated with live steam to kill the pathogens responsible for seedling blights and damping off, but following steam treatment, any inadvertent recontamination of the soil with these pathogens resulted in even more seedling blight than occurred in the natural soil.

He attempted to reproduce the biological factor by adding common soil microorganisms back to the steamed soil. This was the first attempt at biological control of plant diseases by the deliberate release of microorganisms into soil. The effectiveness of his treatments approached but could not duplicate that of the natural biological factor of soil that was suppressive to the pathogens of pine seedlings. Thirty years later, in the 1950s, Kenneth Baker, who was with the California Agricultural Experiment Station, developed a method whereby steam and air could be mixed to selectively treat soils at temperatures just high enough to kill pathogens but not so high as to eliminate the biological factor (Baker, 1957, 1962). This relatively simple technology, plus the use of pathogen-free seeds planted into these soils, was the basis for the U.C. System for Producing Healthy Container-Grown Plants (Baker, 1957) and revolutionized the ornamental and bedding plant industries in the United States and other countries.

Hartley's biological factor is just as operative above ground as it is in soil, and a “revolution” is just as possible with field-scale as with container-grown plants. It stands to reason that taking greater advantage of the enormous potential of the biological interactions and natural cycles working in consortium with crops, especially the important food and agronomic crops, is the next big step in making agriculture both economically more viable and ecologically more sustainable.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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CONCEPTS AND DEFINITIONS

Before discussing the challenges and rewards of sustainable agriculture research and education, some basic concepts must be introduced. These definitions refer to the plant side of agriculture, but they could possibly be adapted to livestock systems as well.

The Elements of Crop Production Systems

Any crop production system can be subdivided, on the basis of component elements, into (1) inputs, (2) biological processes, and (3) depletions or net losses (Figure 3-1A).

The biological processes include photosynthesis, genetics of the crop in terms of its adaptation to the soils and climate and resistance to pests and diseases, biological nitrogen fixation, nitrogen cycling in the soil, phosphorus uptake by mycorrhizal fungi associated with roots, plant defense by plant-associated microorganisms and natural enemies of insect pests, and soil sanitation by the natural soil microbiota.

The inputs include the fertilizers, water, where irrigation is practiced, pesticides, labor, and energy.

The depletions or net losses are largely earth resources and include the organic matter and mineral nutrient contents of the soil, water reserves and water quality, soil lost through erosion, and fossil fuels.

The relative contributions of these three component elements to crop production on any given farm vary with the farming system. Some systems attempt to reduce inputs and make greater use of biological processes; others use more inputs and depend less on biological processes. These components refer only to those elements that are involved directly in crop production and do not include broader considerations such as food safety.

Crop plants growing wild in their native ecosystems depend only on the biological processes (Figure 3-1B). There are no external inputs and basically no net depletions; more likely, there are net gains in earth resources through the soil-building processes of undisturbed ecosystems. Crop plants in the wild present a valuable source of germ plasm and biological control agents for transfer to agricultural systems, and the natural ecosystems present a wealth of clues for assisting in the recognition of potentially useful biological interactions, but these natural systems, by themselves, cannot support the human race.

Sustainable agriculture is a goal aimed at not only allowing no net depletions or net losses in earth resources but, ultimately, at rebuilding or restoring the productive capacity of agricultural soils as well (Figure 3-1C). Sustainable agriculture must meet many other criteria, and these are identified in the many definitions provided by Charles M. Benbrook in the

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-1 Conceptual illustrations of the major elements that are directly involved in or affected by (A) crop production, (B) crops in the wild (natural ecosystems), and (C) sustainable agriculture. Source: R. J. Cook and R. J. Veseth. 1991. Wheat Health Management. St. Paul, Minn.: APS Press.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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Introduction to this volume, but fundamentally, so long as agriculture is responsible for a steady depletion of earth resources, it cannot claim to be sustainable. It may move to new unexploited areas and tap new earth resources, but in the long run, it will not be sustainable. Farming systems aimed at minimizing or eliminating the net-depletions element will also reduce many of the external costs of agriculture to society such as the cost of soil and other pollutants in lakes and rivers.

TOWARD SUSTAINABLE SYSTEMS OF WHEAT PRODUCTION IN THE PACIFIC NORTHWEST

The challenges and rewards of research and education toward making agriculture both more profitable and more sustainable can be illustrated by the efforts aimed at identifying and removing the barriers to full and efficient production of wheat in the Pacific Northwest. The work shows:

  • the remarkable significance of microbial interactions in the rhizosphere —negative and positive—to the ability of a crop to produce fully and efficiently,

  • how science can be held up or even misdirected for decades by misinterpretations and misdiagnoses, and

  • the wealth of clues to biological control that can be forthcoming through both empirical and experimental studies of natural processes.

Much of this work was done under the auspices of the tri-state research and education program known as STEEP—Solutions to Environmental and Economic Problems (see the paper by R. I. Papendick, this volume). Some of the work reported here was done after the report Alternative Agriculture (National Research Council, 1989a) went to press, but it could easily have been included in that report.

The Pacific Northwest produces soft white winter wheat on mostly deep silt loam soils with wet mild winters and dry warm (or occasionally hot) summers with long days. These conditions are ideal for winter wheat. Semi-dwarf wheat was introduced into the region starting in 1961 with the release by O. A. Vogel of the variety Gaines (Vogel et al., 1956). This variety and its successors were the first wheat varieties with the ability, when adequately fertilized with nitrogen, to take full advantage of the ideal temperatures, long spring and summer days, and natural water supplies in deep soils in the Pacific Northwest. These new wheat varieties also responded to irrigation, and soon after Gaines was available, a farmer near Ellensburg, Washington, produced a record-setting 209 bushels per acre (bu/acre) with irrigation. Vogel already knew in the 1950s that his then late-generation, semi-dwarf lines were capable of producing 130 bu/ acre (dryland) at Pullman, Washington. However, while the occasional

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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commercial field produced a yield of 100 or more bu/acre, the majority of fields planted to these new wheat varieties in the high-production areas known as the Palouse yielded only 60 to 80 bu/acre, despite the inputs.

On the other hand, farmers with yields nearly double those obtained with earlier varieties of standard height were delighted with their higher yields—the highest in the United States and two to three times the U.S. average for wheat. Moreover, with foreign markets starting to open up, especially in Asia, where people were switching from rice to wheat as staples in their diets, wheat was planted “fence row to fence row.” Meanwhile, Vogel continued to point out that his wheat varieties were not performing up to their proven high potential.

Moreover, if a formula developed for wheat more than 30 years ago is correct—that wheat in this region can produce an average of 6 to 7 bu/acre per acre-inch of available water after the first 4 inches (Leggett, 1959)—then Vogel was right: fields in eastern Washington and adjacent northern Idaho with 18 to 20 inches or more of annual rainfall had enough water and probably enough nitrogen for 110 to 130 bu/acre but were producing only 70 to 80 bu/acre. A vast body of experimental evidence from field trials confirms this basic relationship between available water and average yield potential for soft white winter wheat in the Pacific Northwest (Figure 3-2).

A fact not commonly recognized is that while the attainable yield of a crop increases in proportion to the increasingly more favorable growing conditions, the actual yield responds relatively less because these conditions also favor more damage from pests, diseases, lodging, nutrient shortages, or other hazards (Figure 3-3). However, the potential of the crop to respond to elimination of such constraints is also greater in proportion to the attainable yield. This is not to suggest that crops that are grown under less than ideal conditions are not subject to the effects of pests and diseases. On the contrary, the effects are basically the same; only the margin of response to elimination of these constraints is potentially less.

The ideal growing conditions and the high yield potential for wheat in the Pacific Northwest were the right combination for the work reported below.

The Soil Fumigation Effect

In 1974, William Haglund of Washington State University and R. J. Cook began studies using soil fumigation as a research tool to reveal experimentally the full production capability of the semi-dwarf wheat varieties (Figure 3-4). Yields were higher by 20, 30, and even as much as 50 bu/ acre in response to the treatments, but with the same available water and nitrogen in the soil (Cook and Haglund, 1982; Cook et al., 1987) (Figure 3-5). Those investigators routinely documented 110 to 120 bu/acre and as much as 150 bu/acre of dryland in the fumigated plots.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-2 Relationship between available water and average yields of soft white winter wheat in Washington State. The horizontal bars indicate the range of attainable yield and available water at Lind for wheat after fallow, Pullman for wheat after peas, and Quincy for irrigated wheat. The relationship is based on an average of 7 bu/acre per inch of available water (500 kg/ha per 2.5 cm of available water) beyond the first 4 inches and has been verified repeatedly by the best yields for the respective areas. Source: Modified from G. E. Leggett. 1959. Relationship Between Wheat Yield, Available Moisture, and Available Nitrogen in Eastern Washington Drylands. Washington Agricultural Experiment Station Bulletin 609. Pullman, Wash.: Washing-ton Agricultural Experiment Station (in R. J. Cook. 1986. Wheat Management Systems in the Pacific Northwest. Plant Disease 70:894–898).

The often spectacular soil fumigation effect has been demonstrated many times over the past 40 to 50 years (Cook, 1984), but routinely, it has been dismissed by scientists as a response of the crop to nitrogen or other mineral nutrients released from the killed microorganisms. Researchers have left this phenomenon on the “back burner” as something mysterious and too complicated to sort out. The simple explanations that root health has been improved, that the plants are growing more nearly to their potential, and that root diseases are indeed this important (Cook, 1984; Wilhelm and Paulus, 1980) have not been generally accepted until very recently.

Soil scientists had already shown more than 30 years ago that the fumigation effect cannot be explained by changes in soil chemistry (Aldrich and Martin, 1952). An initial release of about 10 to 15 pounds (lbs) of ammonium-nitrogen (N) per acre in the top 6 inches of soil was measured, which was minor compared with the 120 lbs of inorganic-N made available

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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by fertilization on top of the 50 to 60 lbs released by natural mineralization (Cook and Haglund, 1982). Cook and Haglund (1982) also showed, as would be expected, that nitrification of the ammonium to nitrate was delayed in the fumigated soils.

The breakthrough came in the mid-1970s, when it was discovered (Cook, 1984; Cook and Haglund, 1982; Cook et al., 1987) that two slightly different and relatively mild fumigants gave identical releases of ammonium-N, and both delayed nitrification, but only one gave the increased growth response. These results showed that the increased growth response of a crop to soil fumigation cannot be explained on the basis of changes in the availability of nitrogen. The one fumigant giving the increased growth response also killed the spores of Pythium spp. in soil (Cook and Haglund, 1982; Cook et al., 1987). This was the first direct evidence of the widespread importance of this soilborne pathogen.

Cook et al. (1980) obtained proof of the importance of Pythium damage to roots with a new soil fungicide, metalaxyl, which is specific for Pythium and closely related fungi and which duplicated the soil fumigation effect (Figure 3-6).

FIGURE 3-3 Diagrammatic illustration of increases in crop yield with increases in conditions favorable to the yield of that crop. While the attainable yield (the yield possible) increases in direct proportion to the more favorable conditions, the actual yield also increases, but less responsively because of specific diseases, pests, and other production hazards also favored by the more ideal growing conditions. Source: R. J. Cook and R. J. Veseth. 1991. Wheat Health Management. St. Paul, Minn.: APS Press.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-4 Soil fumigation in progress in the fall just before winter wheat was planted in a field near Walla Walla, Wash. The field was in a 2-year rotation of dry peas (the previous year) alternated with winter wheat. Soil fumigation was used as a research tool to determine the full production capability (attainable yield) of the wheat with all root diseases controlled. Source: R. J. Cook and W. A. Haglund. 1982. Pythium Root Rot: A Barrier to Yield of Pacific Northwest Wheat. Washington State College of Agriculture Research Bulletin No. XB0193. Pullman, Wash.: Washington State College of Agriculture.

This capacity of wheat in commercial fields to yield 20, 30, and even 50 bu/acre more with no increase in nitrogen supply leads to the inescapable conclusion that wheat in the nonfumigated plots, which were typical of the rest of the farmer's fields, must be leaving as unused that amount of nitrogen that is necessary to produce these higher yields of wheat.

Cook and colleagues were fortunate in their trials, in that phosphorus was not limiting in the soils and the dense fibrous root system of healthy wheat is very efficient in exploring the soil. With other crops in other soils, yields have sometimes been lower in response to soil fumigation because the treatment eliminates mycorrhizae— the fungus-root associations involved in phosphorus uptake by plants. On the other hand, an experiment that shows yield depressions when mycorrhizae are eliminated should lead to the question: How much could yields be enhanced if these beneficial fungi could be enhanced?

Thus far, three root diseases have been diagnosed: pythium root rot, which is caused by several Pythium spp. (Chamswarng and Cook, 1985;

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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Ingram and Cook, 1990); rhizoctonia root rot, which is caused by at least two Rhizoctonia spp. (Ogoshi et al., 1990; Weller et al., 1986); and take-all, which is caused by Gaeumannomyces graminis var. tritici (Cook and Weller, 1987). Pythium spp. strip away the root hairs and fine lateral rootlets of wheat (Figure 3-7), Rhizoctonia spp. girdle and sever both the lateral and main roots, and take-all develops as lesions on all roots and progresses into the tiller bases. Of these three, pythium root rot is the most subtle and

FIGURE 3-5 Increased growth response of winter wheat cultivar Stephens following soil fumigation in a commercial field near Pullman, Wash. Wheat in the foreground (natural soil) averaged about 95 bu/acre, compared with wheat in the fumigated soil in the background that averaged 120 bu/acre. Sources: R. J. Cook and W. A. Haglund. 1982. Pythium Root Rot: A Barrier to Yield of Pacific Northwest Wheat. Washington State College of Agriculture Research Bulletin No. XB0193. Pullman, Wash.: Washington State College of Agriculture. R. J. Cook, W. Sitton, and W. A. Haglund. 1987. Increased growth and yield responses of wheat to reduction in the Pythium populations by soil treatments. Phytopathology 77:1192–1198.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-6 Increased growth response of winter wheat cultivar Stephens to a seed treatment with the fungicide metalaxyl (specific for Pythium spp. in the trials). This response is typical of the responses of several trials done in the Palouse area in 1979 to 1981, and shows the uniformly debilitating effect of Pythium spp. on the growth of wheat. Source: R. J. Cook and W. A. Haglund. 1982. Pythium Root Rot: A Barrier to Yield of Pacific Northwest Wheat. Washington State College of Agriculture Research Bulletin No. XB0193. Pullman, Wash.: Washington State College of Agriculture.

was the most difficult to diagnose, but overall, it may be the most important.

Plants affected by any combination of these diseases look underfertilized (see Figure 3-6) because of the reduced capacity of their root systems to take up nutrients, and often, farmers who notice the uniformly yellowed and stunted appearance of the crop apply more nitrogen, which may or may not help the crop. The mixture of pathogens is dynamic, in that control of only one pathogen can open the way for more damage by the other pathogens and, hence, no overall change in the performance of the crop. With little or no benefit of standard seed treatments and the total impracticability and

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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unacceptability of soil fumigation for wheat, researchers have been forced to look for alternatives that can be used to control these diseases.

The Crop Rotation Effect

The average yield response of wheat to soil fumigation in areas with at least 18 to 20 inches of rainfall or rainfall plus irrigation has been 70, 22, and 7 percent, respectively, in fields that are cropped every year (monoculture), every other year (2-year rotations), and every third year (3-year rotations) to wheat (Figure 3-8). As the length of the rotation was increased, up to a maximum of 2 years between wheat crops, the yields in nonfumigated plots were proportionally higher and the yields in fumigated plots were proportionally less (Cook, 1990). In other words, crop rotation is nearly as effective as soil fumigation as a means of achieving the high yields of semi-dwarf wheats in the high-production systems of the Pacific Northwest.

According to the evidence, the fumigation effect and the rotation effect are the same: both provide a means of eliminating root diseases as production constraints, one that is chemical, which takes about 2 days, and one that is biological, which takes about 2 years. Soil fumigation has become a substitute for crop rotation with many high-value vegetable and fruit crops throughout the United States (Wilhelm and Paulus, 1980), but it is not a viable alternative for agronomic crops.

Research by Crookston and associates (1988, 1991) at the University of Minnesota similarly shows that yields of corn are 10 to 15 percent higher after soybeans than after corn, and that yields of soybeans are 8 to 17 percent higher after corn than after soybeans (Figure 3-9). Even the yields for these crops grown in alternate years (2-year rotations) are less than yields for the same crops in the first year after a break from corn or soybeans for 3 or more years.

Like the results described above for wheat in the Pacific Northwest, the work of Crookston and associates (1988, 1991) indicates that yields of corn and soybeans are potentially highest with 3-year (or longer) rotations, such as might be achieved with small-grain crops, in addition to corn and soybeans. And like the results described above for wheat in the Pacific Northwest, these higher yields cannot be attributed to greater nitrogen availability. This is elegant work carried out over several years and is in direct contradiction to earlier claims that corn can be grown continuously without sacrificing yield potential.

It should be pointed out, however, that since the rotation effect in the Pacific Northwest is basically a process of soil sanitation achieved with the microbial activity of soil—a biological factor—it is probable that the lower the soil temperature or the drier the soil the slower the process. It may be that 2-year rotations in the central or southern states are the equivalent of

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-7 Typical damage of Pythium spp. to the fine rootlets and main roots of wheat, starting with (top) invasion and destruction of root hairs, followed by (bottom) a complete stripping away of the root hairs and rootlets and discoloration of the cortical tissues of the main roots.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-7 (Continued) These white healthy roots came from fumigated soil. Source: R. J. Cook, J. W. Sitton, and W. A. Haglund. 1987. Increased Growth and Yield Responses of Wheat to Reduction in the Pythium Populations by Soil Treatments. Phytopathology 77:1192–1198.

3-year rotations in northern states, such as Washington and Minnesota. More work on this is needed.

Crookston (1984) has not yet diagnosed the factor(s) that is responsible for what he calls the “monoculture effect” controlled by the “rotation effect.” He has ruled out common factors such as corn rootworm, nematodes, and brown stem rot of soybeans. The results in the case of corn point clearly to the presence of a negative factor that persists in the soil when corn is grown continuously and not a growth-promoting influence on corn left in the soil by growing soybean (Crookston et al., 1988). Some root diseases can be very difficult to diagnose, especially those such as the ubiquitous pythium root rot where the root hairs and fine lateral roots destroyed by the disease remain in the soil by most standard methods of root recovery. It is well established that the continual presence of the roots of one crop selects for microorganisms that can break down the roots of that crop; Cook et al. (1987) allowed time for the antagonistic microorganisms to displace or destroy the root pathogens specialized for one crop while growing other unrelated crops.

It is not the presence of different crops that leads to the rotation effect, but rather, it is not growing the same crop year after year in the same field that allows for expression of the rotation effect.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-8 Response of winter wheat to soil fumigation as influenced by the length of the crop rotation in eastern Washington and northern Idaho. Source: From R. J. Cook and R. J. Veseth. 1991. Wheat Health Management. St. Paul. Minn.: APS Press.

The idea that root diseases can be controlled by crop rotation goes back many years. In 1909, H. L. Bolley (see Stack and McMullen, 1988, p. 8) at what was then the North Dakota Agricultural College (now North Dakota State University) pointed this out to farmers in a poster that read:

The reason for crop rotation is not particularly to prevent loss of fertility. It is a sanitary measure. Proper rotation frees the soil from specific crop diseases. No matter how fertile the land, you cannot raise heavy seed if the mother seeds carry fungus diseases internally. Flax does this, wheat does, oats and barley do. Nor can you raise heavy seed wheat if soil is wheat sick. Our old wheat lands are not “worn out”—they are full of diseased wheat roots and stubble. ROTATE.

The challenge in educating farmers on the value of the rotation effect comes when half or all of their farm is wheat base. Moreover, farmers

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-9 (A) Grain yield of corn grown under monoculture (CONT) or alternated (ALT) with soybean. (B) Grain yield of soybean grown in monoculture (CONT) or alternated (ALT) with corn. Bars with the same letter are not significantly different at p = 0.05. Source: R. K. Crookston, J. E. Kurle, R. J. Copeland, J. H. Ford, and W. E. Lueschen. 1991. Rotational cropping sequence affects corn and soybean yield. Agronomy Journal 83:108–113.

averaging 70 bu/acre in each of 3 years produce a total of 210 bu in a 3-year cycle, compared with those with 3-year rotations who produce an average of only 100 to 110 bu in a 3-year cycle. With a government-guaranteed target price and subsidy per bushel of wheat up to the so-called proven yield on the farm, they are assured of an acceptable net return with continuous wheat, even with root diseases.

Yet, a yield of 110 bu/acre every third year has the lowest cash cost per bushel and the maximum return per acre of wheat. Moreover, the net return from the respective rotation crops, namely, spring barley and then either

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

FIGURE 3-10 Diagrammatic illustration of the winter wheat, spring barley, pea, or lentil rotation used as a 3-year rotation in eastern Washington and northern Idaho and some projected benefits. Source: Modified from R. J. Cook. 1989. Biological control and holistic plant-health care in agriculture. American Journal of Alternative Agriculture 3:51–62.

lentils or peas, needs to be competitive only with the net profit of 50 to 60 bu of wheat per acre per year while the field is not planted to wheat.

In addition, fields in a 3-year rotation typically can be planted directly with no prior tillage without the yield penalty when the no-till method is used in combination with continuous crops of wheat (see next section), and farmers have no reason to burn the stubble, as many do when they grow wheat year after year in the same field. Equally important, a field in winter wheat only once in 3 years is injected with a heavy dose of anhydrous ammonia only once rather than three times in each 3-year cycle, which should delay soil acidification. Wheat grown in the 3-year rotation meets the definition of both maximum economic yield and sustainable agriculture (Figure 3-10).

Wheat growers attempting to produce maximum yields with intensive wheat cropping commonly claim that their crops respond to more nitrogen or phosphorus than is recommended from soil tests. With the absorptive capacity of the roots greatly reduced because of disease, it seems likely

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

that the surplus fertilizer and better placement compensates, in part, for the lack of roots.

The reward comes in watching the average yields in these high-production areas increase by 20 to 30 bu/acre without changes in the rates of nitrogen and with the same amount of rainfall when the farmer switches to a 3-year rotation. The reward also comes when a grower reports that he is putting more wheat in the bin with only one-third of his farm in wheat than he used to put in the bin with half his farm in wheat.

Despite its simplicity and the overwhelming amount of evidence in favor of the importance of crop rotation for root disease control, like the soil fumigation effect, the notion is still not widely accepted among plant and soil scientists. It is still relatively uncommon in research reports on results of fertilizer trials, water use efficiency, or similar agronomic factors to state the crop history of the field in which the work is done, apparently because the previous crops (other than a nitrogen-fixing legume) are not considered important to the yield potential of the next crop in any given field. Individual state recommendations on intensive crop management or maximum economic yield (MEY) focus intently on planting, fertilizing, and then caring for the crop with little or no reference to what was or should be grown in the field the previous year or years.

A true MEY system applied to any given crop in any given field needs to be started 2 and even 3 years before the field is planted to that crop rather than the year the field is planted without regard to the cropping history.

One of the greatest challenges in education is how to effect a paradigm shift within the plant and soil sciences toward a greater appreciation for the significance of root health in matters now attributed to soil fertility.

The Crop Residue Effect

The high cost to progress in agricultural research of not recognizing the importance of crop rotation to root health is perhaps best illustrated by the misinterpretations and even the misdiagnoses of the crop residue effect on wheat in the western states starting in the late 1940s and early 1950s.

Stubble-mulch farming was introduced in these areas in the wake of the Dust Bowl days to slow soil erosion. Almost immediately, researchers observed that in the wetter areas or years, yields of wheat were lower when the crop residue was left on the soil surface, which is typical of mulch tillage, than when it was buried, which is typical of clean tillage. Zingg and Whitfield (1957) reported that in 108 separate comparisons at eight locations in the Great Plains and Pacific Northwest, the wetter the climate of the area, the greater the shortfalls in yields with mulch tillage relative to those with clean tillage (Figure 3-11). Total yields were higher in the

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-11 The yield ratio for wheat at different locations in the western states grown with mulch tillage (crop residue left maximally on the soil surface) versus clean tillage (crop residues buried). The wetter the area, the lower the yield with mulch tillage compared with that with clean tillage. Source: A. W. Zingg and C. J. Whitfield. 1957. Stubble-Mulch Farming in the Western States. Pp. 1–56 in U.S. Department of Agriculture Technical Bulletin 1166. Washington, D.C.: U.S. Department of Agriculture. Explanations from R. J. Cook and R. J. Veseth. 1991. Wheat Health Management. St. Paul, Minn.: APS Press.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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wetter areas than they were in the drier areas, regardless of tillage, but the performance of wheat with mulch tillage dropped below that with clean tillage proportionally more with increasing rainfall.

Wheat grown with mulch tillage in the problem areas looks undernourished, and therefore, early work focused on nutrient deficiencies that were thought to be caused by a relatively greater nutrient tie-up if the crop residue was left on the soil surface than if it was buried. This hypothesis was ruled out (reviewed in Cook [1990]), and attention was directed to the crop residue itself, or its decomposition products, as possibly being phytotoxic or allelopathic to the wheat (reviewed in Elliott et al. [1978]). Work on the suspected phytotoxins in wheat straw continued over nearly four decades in several U.S. states as well as in Australia and England (reviewed in Cook [1990] and Rovira et al. [1990]).

In virtually all of the past studies on wheat crop residue effects and wheat health and yield, the sites have been either wheat crops year after year or wheat-fallow-wheat. How else can one plant wheat into wheat stubble unless the site is cropped to wheat after wheat? Even with an intervening fallow, the field is often allowed to green-up early in the fallow period because of the grass weeds and volunteer wheat that can serve as a green bridge between crops of wheat—in a sense, another wheat crop.

Moore and Cook (1984) confirmed, for conditions in eastern Washington, that the problem was microbiological in origin by showing that it could be eliminated with soil fumigation (Figure 3-12). Indeed, when the soil and residue were fumigated, yields were even higher if residues were left on the soil surface than if they were buried (Moore and Cook, 1984), presumably because the surface residues served as a barrier to the evaporative loss of water from the soil so that more water was available to the wheat. On the other hand, burning of wheat stubble in subhumid areas such as the Palouse region not only is detrimental to soils in the long term in lost organic matter but it also costs yield potential in the short term because the bare soils lose valuable water and, hence, yield potential.

It has also been shown (R. J. Cook, unpublished data) that fresh wheat straw layered as a mulch on a site cropped to lentils the previous year had no negative effect on the growth and yield of wheat. On the contrary, yields were greater by 12 bu/acre in response to the mulch. Yields of winter wheat are consistently higher with reduced tillage than with conventional tillage if the field is in a 3-year crop rotation with wheat no more than every third year.

Take-all, pythium root rot, and rhizoctonia root rot each have been shown experimentally to be more severe in fields with reduced tillage than in fields with no tillage (Cook et al., 1980; Moore and Cook, 1984; Rovira, 1986; Weller et al., 1986). The surface residues serve the pathogens as a secondary source of energy (with the living roots of wheat being their

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-12 Spring wheat planted at Pullman, Wash., into soil cropped to winter wheat the 2 previous years (monoculture) with (left) or without (right) tillage and with (top) or without (bottom) soil fumigation. These two drill strips were typical of all four replicates in the experiment and has been repeated in the Palouse region many times.

primary source of energy), but more importantly, the surface residues are thought to keep the top few inches of soil, where these fungi reside, more ideally moist for their activities as root pathogens.

Across the United States, grass weeds, leaf diseases such as tan spot, and several insect pests of wheat, most notably the Hessian fly, are also favored by leaving the crop residue on the soil surface and can be controlled by crop rotation. However, these problems can be seen above ground and are relatively easy to diagnose, whereas the root diseases, because they are out of sight, are not so obvious, and have therefore gone mostly undiagnosed or misdiagnosed.

Because studies of root diseases did not rule out allelopathic chemicals as still another factor, tests were conducted to determine whether the microorganisms responsible for the effect and eliminated by soil fumigation were in the soil or in the straw. These experiments, which were conducted in the field at two locations, showed that the etiologic agents are in the soil (probably in the old root tissues) and not in the straw, where they would need to be if phytotoxic decomposition products from the straw were important (Cook and Haglund, in press; Figure 3-13).

Crookston and Kurle (1989) have also tested the hypothesis that the monoculture effect with corn results from an allelopathic effect of the corn

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

residue. They placed corn residue on plots planted to soybeans or corn, but the only effect they could demonstrate was that of crop rotation.

This focus on the phytotoxin hypothesis and failure to recognize the importance of the rotation effect to root health have held up progress toward solving this problem for at least three decades— from about 1950 until work aimed in the right direction got under way in the 1980s. A proper diagnosis is usually the first big step toward solving any problem of this kind. Any progress toward improving the root health of crops is progress toward the more efficient use of fertilizers and higher net returns, and if this progress also allows farmers to use less tillage without the penalty of reduced yield, then farming systems have moved toward greater sustainability.

These findings and experiences with the crop residue effect support an

FIGURE 3-13 Influence of fumigation (with methyl bromide gas) of the soil only, straw only (as a mulch on the soil), both soil and straw, or neither (all natural) on yields of winter wheat after winter wheat (no crop rotation) in eastern Washington. The only significant yield response occurred when the soil was fumigated, regardless of the nature of the straw on the soil surface. Bars with the same letter are not significantly different at p = 0.05.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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important message of the Alternative Agriculture report (National Research Council, 1989a) that correct diagnoses are beginning to be made of the biological and ecological problems responsible for the recent disappointing performance of many potentially high-yielding cropping systems—systems that have worked well for the short term or in some areas but that are increasingly unreliable.

The Herbicide Effect

In the Pacific Northwest, farmers who grow continuous small grains with no tillage use herbicides as a preplant treatment to eliminate the weeds before planting into the wheat or barley stubble. Of all the possible weeds, the most common are volunteer plants of wheat and barley, especially in the combine row, where the lighter-weight seeds of these crops are most concentrated. The common practice has been to allow the fields to green up with volunteer plants of wheat and barley, grass weeds, and other weeds and then spray them with a nonselective herbicide (e.g., glyphosate [Round-up]) just before planting—usually only 1 or 2 days before planting or even on the day of planting.

Wheat or barley planted in this way developed unusually severe root disease, especially rhizoctonia root rot. Volunteer wheat and barley serve as a “green bridge” for many pests and pathogens between the time of harvest of one crop and the time of planting of the next crop of wheat or barley. In the case of continuous no-till wheat or barley in the Pacific Northwest, the volunteer plants are a reservoir of root pathogen inocula. Upon application, the herbicide weakens these growing plants and their roots systems, in effect shutting down the plant defense mechanisms that normally retard disease development and, hence, the populations of these pathogens. The pathogens, which are already on and within the roots of these host plants at the time of the herbicide treatment, build up to unusually high populations as their hosts begin to die from the herbicide, and this accelerated buildup, when coincidental with the sowing of the next crop, is perfectly timed for a major epidemic of root disease on the next crop (A. G. Ogg, R. W. Smiley, and R. J. Cook, unpublished data).

Volunteer plants and weeds that are killed outright by tillage are subject almost immediately to takeover by the common saprophytic soil microflora, while those plants that are allowed to die slowly, which is typical of the herbicide effect, provide a competitive advantage to the root pathogens that are already in the roots and that have the ability to act as both parasites and saprophytes. Some farmers went broke trying to grow continuous cereals with no tillage and spraying the volunteer plants just before planting. Farmers noticed that the problem was worse when herbicide had been used, even if the field was then also tilled, than when the field was tilled only

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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TABLE 3-1 Yields of Spring Grains in Eastern Washington Directly Drilled into Standing Stubble of Cereal Grains

Soil Type

Spring Wheat (bu/acre)

Spring Barley (lbs/acre)

Fumigated soil

63a

 

Natural soil; volunteer control by glyphosate

2 Weeks before planting

55ab

1,838a

2 Days before planting

43b

1,573b

NOTE: The spring wheat was directly drilled into standing stubble and volunteer plants of winter wheat and included soil fumigation (methyl bromide) to produce a “pathogen-free” check. The spring barley was directly drilled into stubble and volunteer plants of spring barley grown the previous year on the same site. Volunteer cereal plants and weed plants in nonfumigated plots were eliminated 2 weeks or 2 days before planting. The volunteer plants serve as a “green bridge” for root pathogens. Values followed by the same letter are not significantly different at p = 0.05 according to the Duncan's multiple range test.

with no use of an herbicide. Early theories suggested that the herbicide was residual, and the term Round-up injury was proposed, but all the evidence now points to root disease and not herbicide injury.

The proper diagnosis also gave rise to a method of control, at least for no-tilled spring grains, for which this problem has been greatest. By applying the herbicide (e.g., glyphosate) 10 days to 2 weeks before planting, there is enough time for the pathogens to reach their peak levels and then decline to safer levels because of the normally rapid succession of nonpatho-genic microorganisms that move into and rot these tissues (Table 3-1).

The difference between planting immediately and planting 10 days to 2 weeks after herbicide application is the amount of time for the biological factor in soil to have its effect. In this case, the biological factor is the competing soil microorganisms that displace the root pathogens and take over or destroy their energy source.

IMPROVEMENT OF ROOT HEALTH WITH BENEFICIAL MICROORGANISMS IN THE RHIZOSPHERE

Crop rotation is not a permanent solution in all areas of the United States to the problem of root diseases on important food crops such as wheat. In many areas, alternative crops are not available. Moreover, the demand for

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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food crops such as wheat can only be expected to increase, and as the area of land and intensity of cropping increase, so do the pressures from plant pests and diseases increase.

A significant advancement for the biological control of plant diseases is the discovery that on every plant or within every population of plants, there reside microorganisms with the ability to defend those plants. These beneficial microorganisms occur at a very low frequency, but several independent studies show that following several successive outbreaks of the disease, their numbers increase proportionally until an equilibrium is reached or future disease outbreaks are suppressed (Cook and Baker, 1983).

These beneficial plant-associated microorganisms are another example of the biological resource—a biological factor—external (or internal) to the plant.

The importance of this biological factor was highlighted in a report from the National Research Council (1989b) supported by the National Science Foundation and the Competitive Research Grants Office of USDA that points out the enormous potential of this resource and calls for more basic research on the ecology of the microorganisms. These microorganisms hold tremendous potential for increasing plant productivity in ways consistent with making agriculture more sustainable —and possibly also for the development of new products of biotechnology for use in crop protection.

Studies have been conducted in Washington State since 1968 on a phenomenon known as take-all decline, whereby take-all increases in textbook fashion for the first 3, 4, or even up to 7 or 8 years of consecutive wheat crops but then declines while yields recover (Figure 3-14). This pattern has been documented virtually everywhere in the world where soils are favorable to take-all and where wheat has been grown over many years without crop rotation (Shipton, 1975). It has been shown both in Australia and in the United States that there are qualitative and quantitative shifts in the makeup of root-associated bacteria that produce antibiotics inhibitory to the take-all fungus (reviewed in Thomashow and Weller [1990]). These bacteria increase in numbers in the lesions caused by the take-all fungus, inhibit continued progress of the disease, and then cohabit root tissues with the pathogen during its survival or saprophytic phase in soil between the harvest of one crop and the sowing of the next one (reviewed in Cook and Weller [1987]).

Unfortunately, but not surprisingly, a shift in the microbial population toward suppression of one disease may not provide suppression of other diseases in the same ecosystem. Thus, when wheat was grown continuously for 20 years under irrigation in central Washington, the yields declined for the first 7 years because of increasing take-all, recovered over the next 8 years because of take-all decline, and then declined again because of increasing rhizoctonia root rot ( Figure 3-14).

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
×

FIGURE 3-14 Changes in yields of winter wheat with changes in occurrence and severity of root diseases. Source: R. J. Cook. 1989. Biological control and holistic plant-health care in agriculture. American Journal of Alternative Agriculture 3:51–62.

For the past 10 years, researchers have tested the possibility that strains of suppressive bacteria from the rhizosphere of wheat can protect wheat in fields where take-all or other root diseases are yield-limiting factors, if the numbers of these bacteria can be increased in the rhizosphere in advance of infection. Strains were isolated from the rhizosphere of wheat growing in soils from fields where take-all had declined. These strains have been applied singly and as mixtures to the seed with significant biological control (Figure 3-15).

Bacteria that are applied as a living seed treatment are carried passively downward into the soil with the elongating root, where they multiply to the limits of the energy available from the root in competition with the native rhizosphere microorganisms (Howie et al., 1987). In some 10 trials carried out over several locations in Washington in fields where take-all was the dominant yield-limiting factor, an average 10 percent greater yield was achieved with one mixture of strains and 15 percent greater yield was achieved with a different single strain (Table 3-2 and Table 3-3). If there were a wheat variety that averaged a 10 to 15 percent greater yield than

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-15 Response of spring wheat at Pullman, Wash., to biological control of take-all by seed bacterization with natural strains of fluorescent Pseudomonas spp. The plots had three rows each, as follows: left, no disease and no seed bacterization; center, pathogen introduced the same as done with plot on left, but seed treated with two bacteria active against the pathogen; right, severe disease (pathogen introduced) and no bacterization. Source: D. M. Weller and R. J. Cook. 1983. Suppression of take-all of wheat by seed treatments with fluorescent pseudomonads. Phytopathology 73:463–469.

TABLE 3-2 Wheat Yields in Washington State in Response to Seed Treatment with Indicated Strains of Fluorescent Pseudomonas spp.

Location, Year

Untreated (check) (bu/acre)

Yield (bu/acre)(percent change)

   

Strain 30-84

Strain 2-79 + 13-79

Wilbur, 1982

90.1

 

109.8 (22)

Mt. Vernon, 1982

64.2

 

70.4 (9.7)

Ephrata, 1983

103.8

 

105.0 (1.3)

Ephrata, 1984

103.0

 

105.0 (1.9)

Mt. Vernon, 1984

55.2

 

60.8 (10.1)

Ephrata, 1985

110.2

105.8 (−4)

110.2 (0)

Mt. Vernon, 1985

27.4

40.6 (48)

36.4 (32)

Mt. Vernon, 1986

81.9

95.5 (18)

86.1 (5.1)

Yakima, 1986

90.6

87.5 (−2.7)

89.0 (−1.1)

Mt. Vernon, 1987

50.8

60.0 (18.5)

65.5 (25)

   

15.6

10.6

NOTE: Fields were cropped repeatedly to wheat (no crop rotation) with take-all as the yield-limiting factor. Each value is the average of at least four replicate treatments in a commercial field. The plots were planted as drill strips by the farm owner or with the owner's drill.

SOURCE: R. J. Cook and D. M. Weller (unpublished data).

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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the standard, it would be considered resistant and would be released, assuming it met all other standards as well. These bacteria, together with the wheat roots, present the equivalent of resistance to this disease, and they can be used in combination with virtually any existing wheat variety.

While single strains have been effective in some trials, the best overall and most consistent performance has come from mixtures of strains (Cook et al., 1988; Pierson and Weller, 1990; Weller and Cook, 1983). Like artley's (1921) classic work, mixtures are best, but even these have not performed up to the standard of the naturally suppressive soils.

Using the tools of recombinant DNA technology, Thomashow and Weller (1988) and Thomashow et al. (1990) showed for the first time that antibiotic production occurs in the rhizosphere and can protect roots against infections. The antibiotic in this case is phenazine-1-carboxylate (Brisbane et al., 1987; Gurusiddaiah et al., 1986), although other mechanisms of inhibition are also operative. To test the role of an antibiotic such as phenazine, producer strains were made deficient in their ability to make this antibiotic by inactivating a specific gene in the organism needed for antibiotic biosynthesis (Thomashow and Weller, 1988). This inactivation was accomplished by Tn5 mutagenesis, whereby a transposable element of foreign DNA is inserted randomly into the organism's chromosome until

TABLE 3-3 Yields of Stephens Soft White Winter Wheat at Mt. Vernon, Washington, in 1987

Seed Treatment

Yield (bu/acre)

Percent Change from Untreated Check

Check (no treatment)

50.7c

 

Methylcellulose check

51.6c

2

Triadimefon (alone)

64.8a

28

+ metalaxyl + captan

64.9a

28

+ strain 30-84

64.5a

27

Strain 30-84 (alone)

69.0ab

18

Strain 2-79 (alone)

55.5bc

9

+ 13-79 + R4a-80

63.4a

25

NOTE: Seed was treated as indicated in the table and planted in a field cropped to wheat for the fourth consecutive year. Each value is an average of six replicates as drill strips planted with the farmer's drill in a field naturally infested with Gaeumannomyces graminis var. tritici. Values with the same letters are not significantly different at p = 0.05.

SOURCE: Data from R. J. Cook, D. M. Weller, and E. N. Bassett. 1988.Effect of bacterial seed treatments on growth and yield of recroppedwheat in western Washington, 1987. P. 53 in Biological and CulturalTests, Vol. 3. St. Paul, Minn.: APS Press.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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strains appear that are no longer able to make the antibiotic. By using a technique known as complementation, DNA from a library of the wild-type DNA is used to restore the ability of the mutant strain to make the antibiotic.

Antibiotic-negative mutants generated by Tn5 mutagenesis were greatly reduced in their ability to protect wheat against take-all, but mutant derivatives that were restored in their ability to produce the phenazines were coordinately restored in their ability to protect wheat roots (Thomashow and Weller, 1988) (Figure 3-16). The genes for antibiotic production have now been cloned and have been expressed in other bacteria, including strains of bacteria inhibitory to take-all by other mechanisms (D. Essar, L. S. Thomashow and L. S. Pierson, USDA, Agricultural Research Service, Pullman, Washington, personal communication, 1990). It is expected not only that wild-type strains will be mixed but also that genetic traits within the same strain will be mixed to improve the effectiveness of this biological control.

The antibiotic is delivered in molecular quantities only where and when needed, in the same way that natural antibiotics produced by plants in their own defense are produced in molecular quantities only at the sites of infection and usually not throughout the entire plant. Energy is not spent to any significant extent until or unless the plant is threatened by infection.

It should not be surprising that plants would support populations of microorganisms on and within their leaves, stems, roots, and other parts—a biological factor—with the ability to provide the first line of defense against infections and insect attack. The challenge is in how to identify and understand these associations, but the reward is a new dimension to plant improvement—a genetic system external to but complementary of the plant's genetic system. These beneficial microorganisms also become a source of genes for future plant improvement and pest control with transgenic plants. However, it seems doubtful that transfer of a single gene or a few genes from one of these beneficial bacteria to the plant can duplicate the multiple mechanisms and benefits of the organisms when they are present and are associated with the plant.

Greater knowledge of these biological interactions and cycles could help reverse a situation of too little progress on biological control. Too few programs have approached the development of microbial biocontrols by starting with nature's own best systems as a source of candidate organisms.

In concluding this section, the following question must be asked: How many other biological interactions and processes of this kind are working or could be working for the benefit of crop production but are still waiting to be discovered?

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-16 Suppression of take-all by phenazine-producing and nonproducing bacterial strains. Seedlings were from experiments in which (A) nontreated seeds or (B) seeds treated with antibiotic-negative Tn5 mutant, (C) mutant strain restored for antibiotic-producing ability or (D) wild-type antibiotic producer was applied. Source: L. S. Thomashow and D. M. Weller. 1988. Role of phenazine antibiotic from Pseudomonas fluorescens in biological control of Gaeumannomyces graminis var. tritici. Journal of Bacteriology 170:3499–3508.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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ALTERNATIVE AGRICULTURE

The report Alternative Agriculture (National Research Council, 1989a) calls attention to the evidence that agriculture stands to gain in both economic terms and ecological sustainability by taking greater advantage of the biological interactions and natural cycles that are already at work or available to work on the farm. When pesticides upset or mask this natural biological resource, it may be advantageous to use them in a more sophisticated way or find alternatives that more nearly optimize the benefits of these biological processes external to but associated with the crop. This was the approach used by Baker (1957) in the 1950s to get around the problem of the excess heat treatment of soil that destroyed Hartley 's (1921) biological factor that was suppressive to soilborne pathogens. Baker did not eliminate steam treatment. He turned, instead, to milder treatments to eliminate the pathogens selectively while leaving a complex microbiota as a source of biological buffering against reinvasion of the soil by pathogens. It is not proposed that a herbicide such as glyphosate be eliminated as a tool for the management of volunteer plant cereals and weeds, but it is proposed that it be applied to permit time for soil microorganisms to compete with and reduce the energy supply of the pathogens.

Alternative agriculture is a process or strategy used to guide decisions with the goal of making the farming enterprise more sustainable both economically and ecologically. It is not a distinct set of farming practices, methods, or systems (Figure 3-17). Moreover, there is no intrinsically

FIGURE 3-17 Diagrammatic illustration of some features that distinguish conventional and alternative agriculture, but it should be pointed out that these farming systems also tend to overlap in many ways.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-18 Diagram of the levels of practices, inputs, and mechanisms that could be considered in designing sustainable farming systems. N, nitrogen; IPM, integrated pest management; PKS, phosphorus, potassium, sulfur. Source: Modified from R. J. Cook and R. J. Veseth. 1991. Wheat Health Management. St. Paul, Minn.: APS Press.

correct way to proceed since different soils, climates, and markets require different practices, methods, or cropping systems. Nevertheless, the same general ecological principles can be used to guide the process, whether in a given field, on the farm, within a specific region, or across the United States.

The basic ecological principles and benchmark indicators of sustainability have been covered adequately in other chapters of this volume. Instead, a pragmatic guide to the process of designing sustainable farming systems is proposed in Figure 3-18. This guide examines the alternatives starting with

  • making maximum use of biological interactions and cycles already working on the farm;

  • making a one-time or occasional input that is long-lasting or perhaps even self-maintaining; and

  • making regular inputs in the form of purchased fertilizers, pesticides, plant-asociated microorganisms, and seeds.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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Making Maximum Use of Biological Interactions and Cycles on the Farm

Among the on-farm practices or methods are the use of crop rotations and disease-suppressive soils together with less tillage, the optimization of biological controls of insects by using indigenous natural enemies within and across agroecosystems, more innovative use of nitrogen-fixing crops, and maximization of general mechanisms of resistance to pests in plants. Examples of these are provided below.

Crop Rotations and Tillage

Crop rotations and tillage need little further discussion, but the problem of poor performance of crops when they are grown without adequate crop rotation is a general phenomenon that involves much more than small grains, corn, and soybeans. The following terms have emerged to describe the kinds of problems that are encountered and, some presume, to reflect the diagnosis: soil sickness, allelopathy, autotoxicity, the interference effect of corn crops year after year, tired and worn out soil, phytotoxic crop residue, monoculture injury, monoculture effect, and replant problem. Most of these terms are euphemisms for root diseases.

Suppressive Soils

Suppressive soils are soils in which, because of their unique microbiological properties, pathogens, nematodes, or insect pests will not establish; they establish but do not reach economic population thresholds; or they establish and produce disease or cause damage for awhile but then decline while yields recover (Baker and Cook, 1974). As described above for take-all decline, these suppressive soils hold a wealth of clues to biological control (Cook and Weller, 1987). In some cases, it may be possible to recover a single strain of microorganism, genetically alter it to make it more competitive in the rhizosphere, and in this way duplicate the effect. Other cases are too complicated to manage in any way other than empirically by cultural practices or with mixtures of beneficial microorganisms. However, like so many related areas, there are too few investigators of these problems and the progress is too slow.

Boswell (1965) pointed this out 25 years ago. Boswell was then with the Crops Research Division of the Agricultural Research Service, USDA, and a member of the Board on Agriculture of the National Research Council. Working through the National Research Council, he helped obtain funding for the first international symposium on the ecology of soilborne plant pathogens, which was held at the University of California, Berkeley, in 1963

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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and published as a proceedings (Baker and Snyder, 1965). In the forward to that volume, which he termed “A Landmark in Biology,” Boswell (1965, p. 3) wrote:

[I]f the search for disease resistance is not successful, and no industrial chemical or physical treatment is available for economically controlling a soil-borne pathogen, the disease generally goes uncontrolled. Why is the microecological approach so rarely tried on a substantial basis? Is it too slow, too expensive, or just too hard? In view of the stakes to be won, and of some of man's efforts today, none of those terms seem to be applicable.

No area of research offers more to improving both the productivity and the ecological sustainability of cropping systems than does the area of rhizosphere microbiology (Rovira et al., 1990). Understanding and managing the interface between roots and soils are the key not only to root health but also to the greater use of nitrogen fixation, more efficient phosphorus uptake by mycorrhizae, and many other agriculturally important biological processes. Thus far, however, the field suffers from benign neglect.

Biological Control of Insects with Indigenous Natural Enemies

Biological control of insects with indigenous natural enemies is another largely unexplored approach to making greater use of the biological resource external to a crop. One such approach involves the use of predatory insects that have the ability to maintain their populations on alternate or secondary food sources during periods when the population of the target insect pest is low. The potential for this approach has been shown by Coll and Bottrell (1991) for biological control of the European corn borer. The peak density of two insect predators (Orius insidiosis and Coleomeqilla maculata) on corn in western Maryland occurred in response to corn pollen, which these beneficial insects use as a secondary food source, but coincided with the buildup of the corn borer, which these predators then turned to as their primary food source. Buildup of the predators can occur simultaneously with or even prior to buildup of the pest, rather than in response to the pest and often too late for maximum biological control. D. Bottrell (International Rice Research Institute, personal communication, 1990) has suggested that a mixture of corn hybrids, each with the ability to produce pollen at a slightly different time, could help to maintain and stabilize the populations of these pollen-feeding predatory insects even more, provided they are not destroyed by insecticides.

Biological Nitrogen Fixation Using a Legume

Biological nitrogen fixation using a legume in the crop rotation can provide most or, in many cases, all of the nitrogen needs of corn or small

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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grains, depending on the legume and how it is managed (National Research Council, 1989a). The land-grant universities and USDA have all but ceased agronomic research on legumes and their management as alternative sources of nitrogen, but this trend may now be reversed. Nitrogen fertilization accounts for the largest single direct cost to producing crops such as corn and small grains and is often more than the cost of all other off-farm purchases combined (National Research Council, 1989a). Nitrogen losses from the rooting zone also account for much of the present concerns for groundwater quality. Clearly, the greatest impact on reducing the cost of inputs, rebuilding soils, and protecting groundwater will come from bringing more legumes back into the rotations.

Like other challenges and rewards in research and education on matters pertaining to changing agricultural practices, illustrated, for example, by the accounts of recent work on the crop rotation and crop residue effects presented above, the placement of legumes back into the cropping systems may require that researchers and growers dispense with misconceptions, preconceived ideas, and conventional wisdom and try new ideas or reexamine old ones.

Maximizing the General Resistance in Crops to Disease

The general resistance in crops to disease can be maximized by cultural practices that minimize the disease-favoring physiological stresses so common in intensively managed crops. The diseases, in these cases, are caused by the so-called weak parasites or opportunistic pathogens that take advantage of crops under physiological stresses, such as those caused by temperature extremes, salinity, drought, and nutritional deficiencies.

Returning to the case of semi-dwarf wheats in the Pacific Northwest, while farmers in areas with higher amounts of rainfall were pleased with their relatively high yields, farmers in areas with low amounts of rainfall where wheat is grown on summer fallow were not satisfied with their relatively low yields and expected that they, too, should reap the high yields with these “miracle” wheats. By 1964, only 3 years after the Gaines variety of wheat was introduced in the Pacific Northwest, fusarium foot rot had become a major yield-limiting factor in the low-rainfall area (Cook, 1980). This disease is similar to fusarium stalk rot in sorghum and maize and is favored by plant water stress.

Research over about a 10-year period showed that the general resistance of wheat strains to this disease was masked by the water stress caused by too much top growth in response to the high rates of nitrogen (Cook, 1980; Papendick and Cook, 1974). In a nutshell, farmers were fertilizing for 80-and even 100-bu/acre yields in fields that had enough water for only 50 to

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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60 bu/acre. When nitrogen rates were cut back more in line with the available water supplies, the disease ceased to be a problem, except during unusually dry years.

This experience and relatively simple control of a disease illustrates an important principle of sustainable agriculture: that the limits of the cropping systems should be known and respected (Cook, 1989).

Making an Occasional Release, Introduction, or Treatment

The on-farm biological processes and cycles can make major contributions to the productivity of the cropping systems but are not adequate in and of themselves as a means to reach and sustain the full production capability of the crops. Ordish and Dufour (1969, p. 31) put it this way:

[F]arming is a most unnatural activity. Man has imposed on the environment a system of survival of what he wants to use over the Darwinian system of the fittest to survive. Consequently the farmer is engaged in a constant struggle with nature.

Meeting the challenge of this struggle requires inputs as a supplement to the background biological control and natural sources of soil fertility. It can be an even greater challenge to design or come up with inputs that are required only once or occasionally and that become somewhat self-maintaining. Yet, some of the greatest success stories in agriculture have involved this approach and have been based on public-supported research.

Classical Biological Control of Insects

Classical biological control of insects, whereby exotic natural enemies of either a native or introduced insect pest are introduced into habitats or environments where the pest is a problem, has one of the best records of success for investment of all approaches to pest control. According to Ehler (1990), more than 500 releases of predators or parasites have been made worldwide for the control of nearly 300 different species of insect pests over the past 100 years, of which 40 percent are now providing substantial control and 15 percent are providing complete control of insect pests. This is a remarkable record of accomplishment; yet this approach, like other approaches to the biological control of pests and diseases, continues to be inadequately funded and remains largely the work of a few people.

The Deployment of Genes for Disease and Pest Resistance

The deployment of genes for disease and pest resistance in new varieties also has a remarkable record of success. Stem rust of wheat in the Great

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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Plains has been limited to only a few local epidemics since 1954, the year of the last major epidemic of stem rust in North America. This has been accomplished by the strategic deployment of genes for resistance in new varieties released in response to changing patterns of virulence in the pathogen (Roelfs, 1988). The southern corn leaf blight epidemic of the 1970s is lesson enough of what can happen without proper ongoing attention to disease resistance in major crops.

On the other hand, only a few of the many diseases and insect pests of crops are amenable to control by resistant varieties, and all known sources of resistance to some diseases are now in use and have not kept up with the variable populations of pathogens or new biotypes of insect pests. Increasingly, unconventional genetic sources and unconventional methods of breeding will need to be examined to stay ahead of some pathogens or pests and to control others for which there has been no source of resistance to date.

Making Regular Inputs

The on-farm processes or cycles and the on-time or occasional inputs or treatments are rarely, if ever, adequate by themselves for full and efficient crop production, and therefore, this unnatural activity called farming also depends on regular inputs. These are the familiar off-farm sources of fertilizers, pesticides, seed, and possibly in the future, plant-associated microorganisms.

However, these inputs should be used as a supplement to and not a replacement for making maximum use of the on-farm renewable resources. Soil fumigation is necessary for some vegetable and fruit crops (Wilhelm and Paulus, 1980), but to what extent has it become a substitute for crop rotation? Insecticides are essential for the control of some insect pests, but to what extent have they become substitutes for equally effective cultural practices, taking advantage of indigenous natural enemies, or growing the right variety?

One new approach that uses existing technology is to grow varieties as mixtures (Wolfe and Barrett, 1980). The evidence is clear that mixtures of varieties having common maturity characteristics and end-use properties but differing in their traits for resistance or tolerance to environmental or biological stresses can produce both higher average yields and more stable yields over a wider range of conditions (Figure 3-19). Yet, changes from the traditional thinking that pure seed lines are best come slowly. More research data on the value of diverse populations versus single genotypes of crop plants can always be used, but the greatest need at this stage may be in education.

Microbial biocontrol agents typically do not persist in the soil or on plants when they are introduced into these habitats, and therefore, they must be reintroduced on a regular basis. For 70 years, since the pioneering work of Hartley (1921), plant pathologists have been attempting to obtain biological control of soilborne plant pathogens by introducing microorgan-

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-19 Yield as a percentage of standard soft white wheat in Oregon when varieties of similar end-use characteristics were mixed. Unpublished data of C. C. Mundt, L. S. Brophy, and M. R. Finckh.

isms into soil, with there being fewer than half a dozen successes to date, because the agents do not survive in high enough populations long enough or in the right places to do the job. Looking to the future, this situation may change with new approaches. Rather than isolating microorganisms from soil and reintroducing them in mass numbers back into soil, they are now isolated from plants, screened for their ability to inhibit the target pathogen, and then reintroduced back onto the plant (Cook and Baker, 1983). By making selections of candidate strains from plants growing where disease once occurred but has declined, as described above for bacteria that suppress take-all, the chances of finding effective strains are increased.

The International Rice Research Institute is now taking this approach to the control of rhizoctonia sheath blight in Asia (Mew and Rosales, 1986), which is now among the three most important diseases of rice in that part

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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of the world. There is no source of genetic resistance to this disease, and chemical control is either too inconsistent or too expensive. In March 1990, there was an historical planning workshop where rice pathologists from six Asian countries and the International Rice Research Institute decided to concentrate their collective efforts for the next 3 years on screening and testing some 10,000 candidate strains of plant-associated microorganisms representing 15 to 20 environments and rice-growing ecosystems in Asia in an effort to evaluate the potential of this approach to biological control of rhizoctonia sheath blight and other rice diseases in Asia.

This is indeed an exciting approach. Just as public efforts in plant breeding gave rise, eventually, to some highly successful private seed companies, so will public efforts in this new dimension to plant improvement eventually give rise to successful private companies with biocontrol products. For now, however, progress seems to depend largely on public-supported research and education.

Rhizobium Inoculations

Rhizobium inoculations have been carried out by farmers since the turn of the century, yet knowledge of the ecology and practical management of introduced Rhizobium species and strains has not increased appreciably in the past 30 years. Virtually all of the modern-day attention on Rhizobium species is directed at studies of the molecular biology of the root-bacterium association and of nitrogen fixation (Djordjevic et al., 1987; Long, 1984), but there has been virtually no progress on how to establish a preferred strain in competition with less efficient but more aggressive native strains already in the soil.

It is hoped that some of the current molecular biology research results will point the way to future productive research in soil ecology, because unless strains engineered for more efficient nitrogen fixation can be established and maintained in natural soils, continuation of progress will largely be on the present plateau in which only limited benefits are derived from nitrogen fixation. The problem is very similar to that faced by plant pathologists who try to introduce root-associated microorganisms into fields with the seed to control root diseases: how to manage microorganisms in the rhizosphere of crop plants.

THE EXPANDING AGENDA FOR AGRICULTURAL RESEARCH AND EDUCATION

The discussion here is not meant to suggest that research and education should shift the emphasis away from production as a means of making agriculture more sustainable. A temporary shift away from strictly produc-

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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tion-type research may be needed in some cases, but in the long term, both can and must be done. The agenda is not changing; it is expanding.

U.S. agriculture has long given emphasis to ecologically sound farming practices and methods, going back to the establishment of the Soil Conservation Service and Soil Conservation Districts; but political, economic, cultural, and technical forces have worked at cross-purposes to this goal. The problems of the 1980s have compelled U.S. agriculture researchers and growers to think more deeply about the early successes with specialization and the high-yield cropping systems introduced in the 1960s and 1970s and whether they can be sustained. Many have concluded that ecology in all of its aspects must now take its rightful place on a par equal with both increasing production and increasing production efficiency.

A point often overlooked is that farms with highly productive soils benefit more from new technology than do those with severely eroded soils. The introduction of high-yielding semi-dwarf wheats together with new fertilization practices was of benefit on farms with eroded soils but was an even greater boon to farms with deep rich soils. Likewise, the farms that benefited most from hybrid corn were those with soils that could support the full production capability of these new plant types. The actual decline in productivity of a soil is usually so gradual as to go unrecognized in the context of year-to-year variations in yields, and the impact of the loss of each inch of topsoil is also relatively small early in the erosion process. The impact can then increase dramatically, however, with a further loss of topsoil, particularly in shallow soils or over subsoils with low productivities.

It is not good enough to simply decree that 50, 60, 75 and eventually, 100 percent of the acreage of major agronomic crops grown in the United States will be grown with conservation tillage by the year 2000, 2010, or some other target date. Farmers need solutions to the problems—mainly biological problems—that they face with these high-risk management systems. These problems, as pointed out in Alternative Agriculture (National Research Council, 1989a), are amenable to biological solutions.

When considering the major approaches used for pest and disease control —physical, biological, and chemical methods (Figure 3-20)—the emphasis of the past 30 years has been disproportionately weighted toward physical and chemical methods. Tillage, open-field burning, as is often done with wheat stubble in the Pacific Northwest, fumigation, and pesticides can produce spectacular results that farmers can see. In contrast, biological methods are slower acting and less spectacular, and the effects often go unnoticed. Nevertheless, those involved in research and education have a responsibility to help elevate the status and credibility of this approach to the level it so richly deserves. The ability to make agriculture both economically more productive and ecologically more sustainable depends on it.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 3-20 Examples of the physical, biological, and chemical elements of crop health management. Source: Modified from R. J. Cook and R. J. Veseth. 1991. Wheat Health Management. St. Paul, Minn.: APS Press.

The integrated pest management (IPM) efforts aimed at specific disease and pest problems must continue, but it is no longer good enough to fragment research and education efforts into IPM for insects, IPM for diseases, IPM for weeds, and IPM for nematodes, leaving the real integration to farmers. The agenda must be expanded to include more holistic approaches, perhaps developed around the principles of plant health management (Cook and Veseth, 1991).

Pests, diseases, and the abiotic constraints to plant health must be dealt with in ways that are both ecologically sustainable and economically profitable, but doing so will also become increasingly more technical. Some people question whether educational institutions are providing the right kind of training for practitioners of plant health and suggest that there is a need for a doctor of plant health comparable to the doctor of veterinary medicine or general practitioner in human medicine (Browning, 1983). Making greater use of biological controls and biological nitrogen fixation may come in the form of new products, but it will just as likely come in the form of new practices where the only commodity for sale is information. Agriculture would benefit enormously by highly trained private as well as public-supported practitioners of plant health.

The ideas presented here are not new, and the notion that agriculture can become both more productive and more sustainable through biology and ecology goes back a long way. Boswell (1965), in his reference to what he called the “microecological approach,” predicted that it could lead to “more

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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enduring and wiser farming practices.” Nevertheless, this is an idea whose time has come. There are both the need and the tools, as never before, to do the research and carry out the education. The challenge is great, but so will be the rewards.

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Rovira, A. D. 1986. Influence of crop rotation and tillage on Rhizoctonia bare patch of wheat. Phytopathology 76:669–673.

Rovira, A. D., L. F. Elliott, and R. J. Cook. 1990. The impact of cropping systems on rhizosphere organisms affecting plant health. Pp. 389–435 in The Rhizosphere, J. M. Lynch, ed. New York: John Wiley & Sons.

Shipton, P. J. 1975. Take-all decline during cereal monoculture. Pp. 137–144 in

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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Biology and Control of Soil-Borne Plant Pathogens, G. W. Bruehl, ed. St. Paul, Minn.: APS Press.

Stack, R. W., and M. McMullen. 1988. Root and crown rots of small grains. NDSU Extension Service PP-785 (Rev.). Fargo, N.D.: North Dakota State University.

Thomashow, L. S., and D. M. Weller. 1988. Role of a phenazine antibiotic from Pseudomonas fluorescens in biological control of Gaeumannomyces graminis var. tritici. Journal of Bacteriology 170:3499–3508.

Thomashow, L. S., and D. M. Weller. 1990. Application of fluorescent pseudomonads to control root diseases of wheat and some mechanisms of disease suppression. Pp. 109–122 in Biological Control of Soil-Borne Plant Pathogens, D. Hornby, ed. Slough, England: C.A.B. International.

Thomashow, L. S., D. M. Weller, R. F. Bonsall, and L. S. Pierson III. 1990. Production of the antibiotic phenazine-1-carboxylic acid by fluorescent Pseudomonas species in the rhizosphere of wheat. Applied and Environmental Microbiology 56:908–912.

Vogel, O. A., J. C. Craddock, Jr., C. E. Muir, E. E. Everson, and C. R. Rohde. 1956. Semidwarf growth habit in winter wheat improvement for the Pacific Northwest. Agronomy Journal 48:76–78.

Weller, D. M., and R. J. Cook. 1983. Suppression of take-all of wheat by seed treatments with fluorescent pseudomonads. Phytopathology 73:463–469.

Weller, D. M., R. J. Cook, G. MacNish, E. N. Bassett, R. L. Powelson, and R. R. Petersen. 1986. Rhizoctonia bare patch of small grains favored by reduced tillage in the Pacific Northwest. Plant Disease 70:70–73.

Wilhelm, S., and A. O. Paulus. 1980. How soil fumigation benefits the California strawberry industry. Plant Disease 64:264–270.

Wolfe, M. S., and J. A. Barrett. 1980. Can we lead the pathogen astray? Plant Disease 64:148–155.

Zingg, A. W., and C. J. Whitfield. 1957. Stubble-mulch farming in the western states. Pp. 1–56 in U.S. Department of Agriculture Technical Bulletin No. 1166. Washington, D.C.: U.S. Department of Agriculture.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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4

Overview of Current Sustainable Agriculture Research

John C. Gardner, Vernon L. Anderson, Blaine G. Schatz, Patrick M. Carr, and Steven J. Guldan

To most Americans, “nature” occupies the country's national parks and wildlife preserves. The vast stretches of the United States that are dedicated to agriculture, however, make farmers and their land the most important components of the contemporary environment. Agriculture is among the most intimate experience that people have with nature, since it is a two-way interaction. It is perhaps this link, the direct impact of people on nature through agriculture, that is at the heart of the current interest in public agricultural policy. The rural population is the most rapidly shrinking and economically stressed sector of U.S. society, and is the sector that has most closely interacted with the nation's most important natural resource base—the land. Alternatives in agriculture must be sought to ensure the permanence of soil and water, an economy that rewards stewardship and maintains rural communities, and an overall social understanding of both the true costs of production and the risks associated with further neglect in developing a global agricultural policy.

Sustainable agriculture research has been widely discussed recently. It is a time of rapid change as farmers, members of industry, researchers, and educators adapt to new ideas. The objectives of this overview are to identify the course that research has taken to date and discuss, largely by example, the process that will be needed to maintain the rapid pace of discovery that has occurred over the past few years.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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THE CHALLENGES

Driven largely by urban environmental and rural economic and social concerns, the long-envied U.S. crop and livestock production process is now being questioned. Are too many chemicals being used? Is the water safe to drink? How much more topsoil can the United States afford to lose? Are foods contaminated with pesticides? Can farmers afford the rising costs of energy and purchased inputs? Can farmers farm without these inputs? While each question may be a legitimate concern, they all deal with symptoms. To date, most of the concern of both the urban public and the agricultural research community has been to describe and quantify the symptoms rather than to uncover the causes and discover the solutions to urgent problems.

It seems that the United States is on the threshold of a new vision for agriculture and the important role it plays in society. Appropriately, agriculture's reexamination has begun with the production process itself. History has repeatedly suggested that economic and social policy will only succeed if it is based on the sound ecological use of natural resources. The use of ecology and its principles, however, is largely unapplied in agricultural settings and seems to gain attention only after events that expose unsuccessful agricultural production practices. Hanson (1939) addressed the Entomology Society of America about ecological thinking after the Dust Bowl and grasshopper problems of the 1930s. Jackson and Piper (1989), Paul and Robertson (1989), and Elliott and Cole (1989) are echoing the plea in the midst of today's soil, water, and food safety concerns. An ecological approach in the study and development of crop production practices, however, is fundamentally incompatible with the typical agricultural research paradigm of reductionistic science. The reductionistic approach assumes that answers to problems are always at the next lower level of system organization; thus, agronomists become physiologists and physiologists become biochemists. This has largely led to the virtual abandonment of adequately funded and staffed applied interdisciplinary systems research programs (Buttel, 1985), including those with an ecological orientation.

Despite the apprehension, use of an ecological perspective could become the fundamental foundation for most sustainable agriculture research. At present, it holds the most potential to guide the search for ways to avoid or ameliorate the negative side effects and to find environmentally harmless approaches to the solutions of U.S. agricultural production problems. It may also help to reveal where potentially dramatic improvements can be made in agricultural productivity and resource-use efficiency. Even the most simple ecosystem models (Figure 4-1) graphically reveal the importance of cycling and the interdependency of all components within the ecosystem. Previously, those working in the agricultural sciences saw

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 4-1 Simplified model of an ecosystem.

only the differences between natural and agroecosystems (Figure 4-2). Now they are beginning to see the value in discovering the similarities (Lowrance et al., 1984). Most of the negative symptoms of modern agriculture are a direct result of either bypassing or ambitiously attempting to remove vital ecosystem components. Under such circumstances, what remains is an ecosystem with a limited ability to cycle nutrients and organic matter and one that becomes increasingly expensive to maintain.

It is within this “new” vision of agricultural production that clues to future improvement may be hidden. Altieri (1983) and others have suggested the ecological approach as the scientific basis of an alternative agri-

FIGURE 4-2 Differences in primary flow of nutrients and biomass between agricultural and natural ecosystems.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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culture system that includes not only soils, plants, and animals but also the people who direct it. The observational and managerial skills of farmers are a key component. Such an agriculture system is now being widely tested through the low-input sustainable agriculture (LISA) research and education program of the U.S. Department of Agriculture.

LISA: SUCCESSES AND LIMITATIONS

The LISA program has perhaps been the most visible and controversial of any agricultural research and education program recently introduced. It was first greeted with skepticism by both the agricultural chemical industry and many land-grant institutions. The popular agriculture trade journals frequently referred to it as a “smokescreen for organic agriculture” (Progress, 1988) and denounced the involvement of farmers and nonprofit institutions as “unscientific.” In retrospect, the involvement of farmers and others outside of the traditional agricultural research circles has offered perhaps the most creative and practical advice yet (Kirschenmann, 1988). LISA has bridged many gaps between farmers, nonprofit organizations, and land-grant institutions, as evidenced by the projects supported thus far and reviewed in this volume (Madden et al., 1990).

LISA has also undoubtedly contributed to agriculture's self-evaluation in recent months. Articles in fertilizer trade journals today refer to the challenge of LISA concepts, the importance of the environment, and the need for knowledge of soil tests and how to apply their results for reasonable application rates and safety. Successful Farming now has an environmental column alongside market reports and herbicide recommendations. In addition, most farm magazines now carry regular sections on how farmers can cope with problems and remind them to savor the joys of modern rural life. A resurgence of agrarianism and LISA have occurred simultaneously, neither of which is coincidental.

One of the most surprising successes of LISA has been the ability to attract matching funds and encourage other institutions to invest likewise in alternative agricultural research and education programs. Ironically, the very mechanism of steering the public research agenda with outside grant money, as suggested by Hightower (1973) in reference to agricultural business and industry, is occurring in the direction of alternative agriculture with LISA. To many field-oriented and applied research programs across the country, LISA has been the first opportunity in some time to compete legitimately for a new source of outside funds. Long-forgotten extension programs involving on-farm research and demonstration are also being revitalized.

While LISA's success in broadening the research team and topics is admirable, it is not without its limitations. As the program matures, it must retain its original and most valuable quality: that of expanding the

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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TABLE 4-1 Major focus of Low-Input Sustainable Agriculture Projects Funded in 1988 and 1989

Project Topic

Percentage of All Projects

Crops

43.8

Economics or sociology

12.3

Fertility or tillage

16.3

Insect management

5.0

Livestock

13.8

Pathogen management

2.5

Weed management

6.3

NOTE: Of the projects funded through LISA in 1988 and 1989, about 25 percent were for demonstration or education and 75 percent were for research. The research projects are displayed by major focus. Studies dealing primarily with economics or sociology make up the remaining 12.3 percent not shown.

boundaries of agricultural research possibilities. Examination of the current research funded through the LISA program by major topic reveals that more than two-thirds of all projects have remained within the comfortable confines of traditional agroecosystems (Table 4-1). Even livestock have largely been ignored because of the scarcity of livestock-based project proposals submitted to the LISA program. Soil microbial aspects beyond a disease control emphasis are incorporated in very few of the projects, and only a handful of the projects funded in 1988 and 1989 examined the whole picture of soils, crops, and livestock.

Much of the LISA research has been the testing of alternative treatments in traditional settings. Beyond the topics of study themselves, the methods need to advance with the discoveries. What may have been novel 3 years ago may now appear simplistic. Old tendencies must be resisted; otherwise, demonstration projects will begin to lose their depth and research projects will lose their breadth. The creation of new methods and innovative inquiry must be seen to be as equally as important as exploration of the performance of an alternative crop or tillage method. Without the development of these new methods, researchers will succumb to the same old boundaries that limited them before. The inquiries must selectively challenge long-held agricultural beliefs that do not fit new ecological, economic, or social realities.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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ECOLOGICAL, ECONOMIC, AND SOCIAL CHANGES ON THE GREAT PLAINS

It is difficult to anticipate, much less identify, changes that occur slowly over several generations. Yet, it is anticipation that is a principal feature of sustainable agriculture. There are many important relationships that must be anticipated: agriculture and the environment, urban and rural society, agriculture and the economy. The ability to perceive changes can be viewed through two examples that greatly affected the land and its people in the Great Plains.

Fallow on the Great Plains

Much of the Great Plains of the United States was transformed from native, perennial prairie grasses to domesticated, annual wheat over a century ago. The effect of this change on the nitrogen and carbon content of the soils is well documented (Haas and Evans, 1957; Hobbs and Brown, 1957). When those reports were published over 30 years ago, there had

Fallowed, or idle, land annually occupies up to one-quarter of all land in the wheat-growing regions of the Great Plains. Traditionally this land is tilled several times each summer to control weeds and mineralize mutrients. Over time, such practices have also increased susceptibility to soil erosion and hastened loss of soil organic matter.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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Virgo black medic (Medicago lupulina) is grown as a “living” mulch fallow substitute crop after grain sorghum in the Central Great Plains. The optimum living mulch would be one that fixes nitrogen symbiotically, is capable of competing with weeds, and requires little soil moisture.

been a decline of approximately 46 percent in the organic carbon content and 42 percent in the organic nitrogen content of Great Plains soils. With the aid of fallow periods to conserve moisture and allow mineralization of nutrients, the prairie pioneers essentially “mined ” the soil.

Faced with this reality, agricultural scientists first recognized the importance of nitrogen and spent considerable time and effort in the study of how best to replace it with nitrogen fertilizer. Over the long term, however, the loss in carbon content may be an equal, if not more serious, problem than the lack of soil nitrogen. As revealed in a recent review on soil tilth (Karlen et al., 1990, p. 158), which was defined as “the physical condition of a soil described by its bulk density, porosity, structure, roughness, and aggregate characteristics as related to water, nutrient, heat, and air transport; stimulation of microbial and microfauna populations and processes; and impedance of seeding emergence and root penetration,” a clear knowledge of its importance was recognized among the scientific community 50 years ago. Such a complex and seemingly unquantifiable property was soon rejected in the reductionistic thinking of the past few decades, however. The past soils textbooks that taught most of today 's scientists largely rejected the term tilth, using the concept in reference to tillage alone and dedicating less than three pages to its discussion (Brady, 1974).

Today, the soils of the Great Plains are thus dramatically different than they were during the early part of the twentieth century. With the loss of tilth and organic matter from both tillage and erosion since then, productiv-

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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“Dead” and “living” mulch substitutes for traditional tilled fallow. Although both alternatives help control soil erosion, the living system, which includes a cover crop, also has the potential for nitrogen fixation, temporary grazing of ruminants, and improvement of soil structure and organic matter content. The living system may also rely less on herbicides to maintain the fallow period.

ity has decreased (Bauer and Black, 1981). Acidification due to nitrogen fertilization is also a problem in the southern Great Plains. The ecology of the soil itself has changed, and there has been less nutrient cycling and greater susceptibility to damage from natural forces caused by changes in soil properties. Yet, tilled fallow remains a management practice for crops that annually cover nearly one-quarter of the land area encompassing the central and northern Great Plains.

Alternative tillage systems offer one possible means of regaining organic matter (Bauer and Black, 1981). Another possibility exists in alternative cropping systems that include the use of legumes for both nitrogen and carbon content improvement, but the scientific literature has discouraged such study. Most work on legumes in rotations in the Great Plains took place in the early 1900s. Summaries of these studies clearly reported that legumes were of no benefit to succeeding wheat crops: “The results of 20 years of experiments with green manure crops show nothing to recommend them” (Sarvis and Thysell, 1936). Similar conclusions were offered 20 years later, but qualifiers began to creep into the summaries: “The crop weather data suggest that with present cultural techniques green manures should not be used” (Army and Hide, 1959). Army and Hide acknowledged that the research reported was set up with ideas based on the traditional approaches used in humid regions and implied that these approaches would not work in drier regions.

Duley and Coyle (1955) speculated that the value of using green manures in the Great Plains may not be realized until after the land had been farmed for a longer time and until further experiments determined the most effective

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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culture methods. Brown (1964) recognized the changes that had occurred in Great Plains soils because of erosion and cropping over time. He also emphasized that the full benefits of cropping systems that included perennial grasses and legumes would not be detected from research plots located on favorable, relatively protected sites atypical from the norm of the Great Plains.

Researchers and farmers must learn to see and adapt to new realities such as the ecological changes that have occurred in the soils of the Great Plains over time. Carbon and nitrogen are needed in Great Plains soils, and legumes used as green manures could help increase the levels of both elements. Rather than rely on old data gathered under a different set of circumstances, researchers and farmers must look to alternative legumes and/or management strategies that are suited to contemporary conditions (Sims, 1989). The analysis must be multifaceted, recognizing all the factors that legumes contribute over time. Reduction of the inquiry to only a water use consumption comparison or some other single factor may mask the future potential of such systems (MacRae and Mehuys, 1989). Had the southern Australians approached the use of green manure legumes as being applicable only to humid regions, they would have missed the development of one of the most innovative approaches of raising wheat and ruminant animals in a dryland region in the world (Puckridge and French, 1983).

The Changing Roles of Livestock

To the typical American, who is at least several generations off the farm, the mental image of a farm always includes livestock. Today this image is mostly nostalgic because farms are typically specialized into either crops or livestock. For example, in North Dakota, farm numbers have dropped at a rate of nearly 1,000 per year since the early 1960s. The number of farms with cattle has dropped at twice this rate (North Dakota Agricultural Statistics Service, 1988). The fewer and larger farms left are mostly crop-only operations. Economic and social changes over the past century have had a profound effect on the presence of livestock in agroecosystems.

The economies-of-scale and transportation were probably the first reasons for concentrating the livestock industry. Meat-packing plants built alongside the rail centers at Kansas City and Chicago gave easy access for the incoming cattle and the outgoing carcasses. The livestock industry is still largely directed by these strong economic forces. The poultry industry is concentrated in the southeast United States, and feeding of beef cattle has dominated in southwest Kansas and the southern High Plains. The largest packing plants are now located near the feedlots, to allow shipping of boxed beef rather than live cattle. The economy of packaging and delivering the highest-quality, most-uniform, and inexpensive meat products to consumers has thus changed the distribution of livestock across the country.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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Social factors have further separated livestock from many farms. With the advent of larger tractors and implements concurrent with larger farms and fields, the mechanization of the entire farm has been appealing. Depending on the type of operation, livestock may require care throughout the year, competing with crop management and leisure time. Although cattle have romantically remained a part of the image of western agriculture, increasingly they do not fit the mold of a contemporary farm. There are also other social factors that have discouraged meat consumption. Health concern about animal fats and animal rights and welfare issues, whether perceived or real, have had an impact on the livestock industry.

Although agroecosystems are possible without livestock, domesticated animals have long been recognized as possible consumers for the agroecosystem (Joandet and Cartwright, 1975). Ruminants have the most potential to diversify and revitalize the agroecosystem because they use forage-based rations. Much of the livestock production, however, has concentrated on the use of high-quality feed grains. Switching from grain-based to forage-based rations would have widespread implications for both the livestock industry and the farm (Wedin et al., 1975). Even the recent attention of organic farming methods has been accompanied by criticism of the perception of requiring too much livestock (Bender, 1988). The enhanced use of livestock to enrich the agroecosystem thus seems confined by rigid economic and social boundaries.

SCIENTIFIC LIMITATIONS

These examples indicate that new methods and thinking will be as important as new plants, animals, or tools in the development of alternative agriculture systems. Although reductionistic science has its strengths, it also has its weaknesses. The scientific community must internalize the criticism that it is not only new ecological, economic, and social situations that must be understood. It must also struggle with the scientific boundaries that limit attempts to meet these new challenges (MacRae et al., 1989).

One of the boundaries is how to perceive and deal with new technologies as they are applied to exercise control over agroecosystems. Many tools for this control have been added in the past century: first, there were mechanical tools, such as tractors, plows, and other inventions; then, there were chemical fertilizers and pesticides. Now, with the current understanding of molecular genetics, biotechnology could spawn a new era of biological tools. Yet, each technology has been slowly understood in how it relates to already existing technologies and the agroecosystem as a whole. Each new technology has been seen as a substitute for the previous one (Figure 4-3): herbicides for tillage, predators for insecticides. In practice, however, the relationships among these technologies in the field seldom

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 4-3 Evolution and current perception of the relationship among agricultural technologies. Linear substitution of one technology for another is currently assumed in many research designs.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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fit the one-for-one substitution vision. Like the resurgence of the term soil tilth, there must also be a broader vision of the agroecosystem's complexity. Most likely, there will be a move beyond studying the substitution of one technology for another and, instead, the interrelationships of technologies will be studied, given that there are likely other influential factors that have yet to be discovered (Figure 4-4).

A logical place to begin practicing such a vision is on a farm itself. Several groups of scientists have begun such studies. The U.S. Department of Agriculture Soil Tilth Laboratory is carefully studying the farm of Dick Thompson, which was featured as a case study in Alternative Agriculture (National Research Council 1989), and his neighbor. The Northern Plains Sustainable Agriculture Society, along with North Dakota State University, is likewise carefully studying nine farms with different management styles across North Dakota. These and other similar ecological studies could identify key aspects of how current agricultural practices actually interrelate with the environment.

Once the agroecosystem is refined on the ecological level, new economic and social policies must be built upon it. Certainly, a longer-term economic vision is needed for agriculture. Too often, good agronomic ideas are aban-

FIGURE 4-4 A possible visualization of the multidimensional relationship among current and yet undiscovered agricultural technologies and the ecosystem.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 4-5 Three of the important boundaries that will shape future agricultural policy emphasizing the few possibilities that may exist that meet universal approval.

doned when the local lender analyzes the plan on an annual ledger sheet. Policies that will reduce the economic risk of ecologically sound, alternative agricultural production systems must be developed. Although many production systems may pass the rigors of environmental protection, economic security, and social acceptability individually, few will satisfy all the facets necessary for a successful and sustainable agriculture (Figure 4-5).

CONCLUSION

While the current emphasis on sustainable agricultural research is on alternative practices, many of these are being tested and studied under rather confining ecological, economic, social, and scientific boundaries that must be tested on an equal basis. Both the treatments and methodologies of research must be expanded to continue the advance toward sustainable agriculture.

As suggested previously by many other investigators, the ecosystem model has been suggested as a reference point to help guide and reveal important missing components in sustainable agriculture research. If such research is to be carried out by individual, discipline-based scientists, ready and willing access to the other disciplines is necessary. Use of a farm itself along with full participation of the people who manage it may serve as an excellent starting point to focus on the whole system, rather than the parts of the system, that makes up agriculture. The involvement of farmers also provides early tests of the appropriateness and practicality of applied re-

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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search. Many other, more basic areas of research may also be suggested with the aid of farmers and on-farm research.

Using the metaphor that agriculture is a conversation between humans and nature, perhaps there has been too much talking and not enough listening. People's observatory skills must be sharpened. People often learn from the most simple and ordinary of experiences. As written in 1854 by Henry David Thoreau in Walden, after his experience at Walden Pond:

It is remarkable how easily and insensibly we fall into a particular route, and make a beaten track for ourselves. I had not lived there a week before my feet wore a path from my door to the pond-side; and though it is five or six years since I trod it, it is still quite distinct. It is true, I fear others may have fallen into it, and so helped to keep it open. The surface of the earth is soft and impressible by the feet of men; and so with the paths which the mind travels.

While LISA and other sustainable agriculture research has proved controversial and challenging, researchers and farmers must not be blinded by its early success, nor satisfied with its current vision. Many challenges lie ahead in the further advancement of agriculture.

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Sarvis, J. T., and J. C. Thysell. 1936. P. 71 in Crop rotation and tillage experiments at the Northern Great Plains Field Station Mandan, ND. USDA Technical Bulletin No. 536. Washington, D.C.: U.S. Department of Agriculture.

Sims, J. 1989. CREST farming: A strategy of dryland farming in the Northern Great Plains inter-mountain region. American Journal of Alternative Agriculture 4:85–90.

Wedin, W. F., H. J. Hodgson, and N. L. Jacobson. 1975. Utilizing plant and animal resources in producing human food. Animal Science 41:667–686.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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5

Economic Considerations in Sustainable Agriculture for Midwestern Farmers

Michael Duffy

Since World War II, chemical pesticide and fertilizer use has increased steadily. In 1988, 96 percent of the acreage planted to corn and soybeans in the United States was treated with a herbicide. Insecticides were used on 35 percent of the corn and 8 percent of the soybeans (U.S. Department of Agriculture, 1989). Similarly in 1988, 97 percent of the acreage planted to corn was fertilized. The average application was 137 pounds of nitrogen, 63 pounds of phosphate, and 85 pounds of potash per acre. Labor use has declined sharply since 1950, while chemical use has increased (Figure 5-1).

The land resources that are used have not changed significantly (U.S. Department of Agriculture, 1986). With changing technology, labor productivity has increased much more rapidly than has crop yield per acre or output/input ratios (Figure 5-2).

Recognition of these costs and unintended environmental costs have given rise to low-input sustainable agriculture (LISA) research. The situation today can be characterized as one in which chemical techniques dominate agricultural production. This domination is so great that many farmers do not count the contribution of internal resources. For example, 52 percent of the farmers in an Iowa survey indicated they ignored the nutrient content of animal manure when deciding how much chemical fertilizer they should apply to their fields (Padgitt, 1987). Several recent surveys in Iowa have confirmed that up to one-fourth of the farmers never take soil tests (Lasley and Kettner, 1989; Padgitt, 1985, 1987).

The Iowa Rural Life Poll reported that (1) 78 percent of the farmers agreed or strongly agreed with the statement that modern farming relies too heavily on insecticides and herbicides, and (2) 76 percent responded to the

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 5-1 U.S. farm input use (1977 = 100). Source: U.S. Department of Agriculture.

statement that modern farming relies too heavily on chemical fertilizers (Lasley and Kettner, 1989). Another survey of the Iowa Farm Business Association members showed that over two-thirds of the respondents recognized that pesticides and fertilizers were a source of groundwater contamination and that pesticides threaten their health (Duffy, 1989b).

The 1980s was a time of financial upheaval in agriculture. At the same

FIGURE 5-2 Change in U.S. agricultural productivity as measured by selected indices (1977 = 100). Source: U.S. Department of Agriculture.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 5-3 Average corn yield by rotation and using no nitrogen or 240 lbs of nitrogen on just corn acres, 1984 to 1989. C, corn; Sb, soybeans; O, oats, M, hay. Source: Kanawha Research Farm, Iowa State University, Ames.

time that farmers had the highest output per unit of input, tensof thousands of farmers had to endure severe financial stress. Research efforts to decrease the costs of production per unit of output has been furthered by the LISA program.

THREE LOW-INPUT FARMING SYSTEMS

Crop rotations are an integral part of most sustainable agriculture systems (with perennial crops and permanent pasture being major exceptions). The lengths of and crops in the rotation have several impacts, which can include nitrogen fixations and reductions in pest populations. Figure 5-3 shows corn yield responses to nitrogen and rotation. Note in Figure 5-3 that corn every other year had almost identical average yields regardless of the crop followed or the level of nitrogen available. In the designation of crop rotation, C represents corn, O is oats, Sb is soybeans, and M is alfalfa and grass meadow. For example, C-Sb-C-O is a 4-year rotation of corn-soybean-corn-oats where corn is grown every other year. Because of the nitrogen fixation by legumes, the corn in the C-O-M-M rotation produced almost identical yields with and without commercial nitrogen fertilizer.

This is an example of the many studies that are examining the impact of rotations and various amounts of fertilizer use, all of which show essentially the same results. One major aspect of sustainable agriculture research is to understand and evaluate rotation benefits. It is obvious from the data that there are more than fertility benefits from a crop rotation.

Manure usage is another integral part of many sustainable agriculture

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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systems. Although animals are not absolutely necessary on every farm, sustainable agriculture recognizes their benefits in terms of added income, more equal distribution of labor demands throughout the year, useful byproducts for crop production (notably manure), and productive use of crop residue (such as corn stalks) as feedstuffs.

Studies of three systems of low-input farming in Iowa and Pennsylvania are described below.

Chemical and Organic Production System Demonstration Project in Northeastern Iowa

This study is a comparison between chemical and organic production systems. The chemical system uses current chemical pest management and fertilizer techniques by which the farm manager decides each year which material and amount of material should be used. Two chemical-based rotations are examined: continuous corn and corn-soybeans. The organic system uses no pesticides or commercial fertilizer. However, in 3 of 12 years, an emergency herbicide treatment was applied. This system follows a 3-year corn-oat-meadow (C-O-M) rotation. Beef feedlot manure is applied at the rate of 20 tons/acre before the corn is planted.

This study is being conducted on 1-acre plots at the Iowa State Northeast Research Center in Floyd County, Iowa. Each crop in each rotation is grown once a year. The study results presented here are for 1978 through 1989 (Duffy and Chase, 1989a).

Figure 5-4 shows the average expenses of the system for machinery,

FIGURE 5-4 Average expenses by input category and rotation, 1978 to 1989. C, corn; Sb, soybeans; O, oats; M, hay. Source: Nashua Chemical/Organic Demonstration Project, Iowa State University, Ames, Outlying Research Centers reports.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 5-5 Average return to land, labor, and management for three alternative rotations and production systems. C, corn; Sb, soybeans; O, oats; M, hay. Source: Nashua Chemical/Organic Demonstration Project, Iowa State University, Ames, Outlying Research Centers reports.

input, and labor. Machinery expenses are estimated based on Iowa State University Extension Service data for every operation for each crop. The input costs are for the amount used and are estimated by using unpublished average price lists. Manure is charged at spreading costs. Labor is for the fieldwork time only, which is charged at $6/hour.

Figure 5-5 shows the preliminary findings of the average returns to land and management both for the rotation system and corn alone. No land or overhead charges were subtracted because these were constant across all systems. Yearly average prices were used in the calculations. The average corn yields were 138, 119, and 98 bushels/acre for corn after soybeans, corn after corn, and corn after meadow, respectively. The average returns with corn in the rotation were $120, $78, and $117 from corn after soybeans, corn after corn, and corn after meadow, respectively (Figure 5-5). However, when the returns for the entire rotation system were calculated, continuous corn earned about the same as the C-O-M rotation, but the C-Sb rotation earned more than the continuous corn or C-O-M rotation did.

Another observation from this project was the relative comparison between C-C and C-O-M. Without government program benefits or premium prices for organic produce, there was essentially no difference in the returns from these two systems. Not all of the benefits from rotation were reflected in annual net returns, however. Reduced use of pesticides and chemical fertilizers and lower erosion rates can yield long-term benefits in terms of water quality, the environment, and human health.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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The nonmonetary benefits between the systems have not been examined thus far. One area of consideration in sustainable agriculture is energy use. It is an issue in both the source and amount used. Commercial fertilizers (especially nitrogen) and pesticides also require energy for their production and use. Figure 5-6 presents one view of energy use in this demonstration project. The energy produced is measured by its value as animal feed. The energy consumed is for machinery operation on the farm plus the energy required for use in the production of inputs.

Very few differences were found in the total energy value of feed produced by the three systems. Energy consumption, however, varied significantly. The greatest factor in energy use was fertilizer. Over three-fourths of the energy used for C-C and C-Sb rotations was fertilizer. It takes approximately 1 gallon of a diesel fuel equivalent of energy to produce 4 pounds of nitrogen.

Three general conclusions can be drawn from this particular study. The C-Sb rotation produced the highest average returns, and the C-O-M rotation was a viable alternative. The C-C and C-Sb rotation systems, however, were more vulnerable to external shocks, especially in energy prices.

Rodale Conversion Project in Kutztown, Pennsylvania

This project is operated and supported by the Rodale Research Center. Its original purpose was to estimate the impact of the starting crop of a rotation when converting to an organic system. The Rodale Research Center uses the term low input to describe their study; pesticides or commercial

FIGURE 5-6 Energy balance from chemical organic demonstration project, 1978 to 1989. Values are average British thermal unit (Btu) equivalents (in millions). C, corn; Sb, soybeans; O, oats; M, hay. Source: Nashua Research Farm, Iowa State University, Ames.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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fertilizers were not used in two of three systems that were evaluated. This study was similar to the Iowa chemical and organic production system demonstration project discussed above.

The conversion project examined three alternative production systems with three alternative starting crops. Each system and starting crop was replicated eight times on 20-by-300-foot plots (Duffy et al., 1989).

The first system used no chemicals or commercial fertilizers. Animal manure was used to supplement soil fertility. The rotation was small grain-hay-corn-soybeans-corn silage. The three starting crops were small grain, corn, and corn silage.

The second system in the project did not use chemicals, commercial fertilizers, or animal manure. The rotation was small grain-corn-small grain-corn-soybean. A legume was planted with the small grain and plowed under to help augment soil fertility needs. The three starting crops were small grain, soybeans, and corn.

The third system followed a conventional chemical and fertilizer program and used the standard recommendations of The Pennsylvania State University (University Park). This system followed a corn-corn-soybean-corn-soybean rotation.

The choice of the starting crop had a major effect on returns over the first rotation cycle. Row crops require more pest management and soil nutrients. Without the rotational benefits for soil fertility and pest management provided by previous legume crops, returns were greatly reduced when the conversion rotation was started with corn.

This finding has implications for farmers. It means that if they are going to use a rotation-based system, then pest management and fertility needs must be augmented in the initial years of the conversion.

The second major conclusion in the Rodale study was that returns for the organic system with manure and the conventional system were not significantly different. Both systems, however, produced significantly higher returns than those of the organic cash grain system without manure.

Farming Systems Project in Central Iowa

A third farming system project is the Iowa State Farming Systems Project (Duffy, 1988, 1989a; Honeyman et al., 1989). This 5-year project started in 1987 on the Allee Research Farm near Newell, Iowa, in Buena Vista County. The three alternative systems examined in this study are based on the level of management used. The first system is low management with very little field information to determine pest management or fertility needs. Pesticides and fertilizers are applied on a routine basis. There are two low-management rotations: continuous corn and corn-soybeans.

The second system is a high-management system that uses pest scouting,

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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soil tests, ridge-till, banded herbicide applications, and manure application. This system also has two rotations: continuous corn and corn-soybeans.

The third system is also high management, but it has the added goal of low chemical usage. Chemicals are used only in emergency situations. This system follows an oat-meadow-corn silage-rye/soybean-corn rotation. In the fourth year, rye and soybeans are double-cropped by planting rye the previous fall and harvesting it as hay the following spring.

Each crop and system is replicated four times on 1.2-acre plots. The choice of materials, the timing of operations, and other management details are determined by a steering committee and by the farmer.

Three years of this 5-year project have been completed. Although definitive conclusions cannot be drawn, some tentative findings are emerging. The most important finding thus far is the importance of farm manager performance in farming systems projects. Experiment stations, on-farm experiments, and other single-operator projects typically hold this key factor constant. No matter how many replications are included in the experimental design, there is only one manager. Timeliness, attention to detail, carefulness, and attitude are a few of the essential managerial attributes. Although they are hard to quantify, these skills are extremely important in determining the success or failure of an alternative production system.

Another important finding is the success with which additional management information can replace the need for capital. Figure 5-7 shows the decrease in variable costs as more management is added.

Figure 5-8 presents the 3-year average return to land and management. As in previously reported studies, no land or overhead charges are included. The high-management, low-chemical system is not described here because of technical difficulties. High management significantly increased returns, especially when a crop rotation (even 2 years) was used.

Conclusion

The three studies described here show the potential for alternative agriculture production practices. As knowledge increases and available tools increase, production practices and profitability will improve.

Results of these studies suggest several areas where further economic consideration must be given.

SUGGESTIONS FOR FURTHER RESEARCH
Profitability

Individual farm profitability is of paramount importance. Understanding of how alternative systems compare must be increased. Similarly, there

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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FIGURE 5-7 Costs of the Iowa State University Farming Systems Project by input category, rotation, and management intensity. LM, low management; HM, high management; C-C, continuous corn; C-Sb, corn-soybean rotation. Source: Farming Systems Project, Iowa State University, Ames, Outlying Research Centers Report 88-31.

must be a better appreciation of how pieces or parts of different systems can be combined. Trade-offs exist between chemical, cultural, mechanical, and biological techniques. What are these trade-offs for the individual farmer? There is no one best system for all farms. All farmers are unique, and so is the land that they farm. Many of the innovations in agriculture came about because of the need to overcome natural boundaries. As a consequence, much of the current technological research must be devoted to correcting mistakes from past innovations. Rather than trying to overcome natural limitations, sustainable agriculture uses the land and other natural resources and management to determine the best systems.

Societal Costs and Benefits

A second area for further consideration is the efficiency of resource use from a societal perspective. As noted above, agriculture production practices can produce unintended social benefits and costs. For sustainable agriculture to be understood, it is critical that these nonmarket impacts be recognized and that an attempt be made to place a value on them.

Soil erosion provides the best example of an external cost. Farmers suffer the loss of future productivity because of soil erosion; however, it also creates on-farm and downstream costs. Organic matter and topsoil are lost. Roadway ditches must be cleaned of the topsoil washed from fields.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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Silt accumulates in reservoirs, and recreation areas deteriorate. Fish and other wildlife are impaired or eliminated. Water quality deterioration, increased municipal water treatment costs, and other environmental problems are other examples of unintended external costs.

Another often overlooked societal aspect of farm resource use is the quality of rural life. Changes in farm production practices and farming systems have led to a decline in the farm population. These demographic changes affect the health and viability of rural communities. In 1990 there are more part-time farmers, more megafarmers, and fewer middle-sized family farms than in previous decades. Better understanding is needed of how current practices affect food safety, rural communities, environmental quality, and resource use.

Farm Family Resources

A third area for economic consideration in sustainable agriculture involves the allocation of resources for farm families. It is essential that the appropriate balance be achieved for sustainable agriculture.

Labor is a major area for consideration in resource allocation. Too much work for laborers can decrease work quality, while too little work for laborers can affect profitability. To understand the labor constraint, labor availability, the effects on timeliness, labor quality, and the trade-offs between capital and labor must be evaluated.

Another farm family resource issue is capital availability—in particular,

FIGURE 5-8 Return to land and management, Iowa State University Farming Systems Project. LM, low management; HM, high management; C-C, continuous corn; C-Sb, corn-soybean rotation. Source: Farming Systems Project, Iowa State University, Ames, Outlying Research Centers Report 88-31.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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how much the production system has an impact on capital requirements. The farming system must be a compatible match with the farm family 's goals and resources.

A final farm family resource issue is managerial skills. Management is crucial in determining the success or failure of a farm. As complexities and options in agriculture increase, farms must consider hiring outside experts, such as those used for pest control scouting.

Government Policies

Government programs and policies are a fourth general area for economic consideration in sustainable agriculture. Although most agriculture policy attention is focused on the 1990 farm bill, many other government policies and decisions, including environmental and health regulations, have an impact on agriculture. Less obvious, but also important, are the impacts of government monetary and fiscal policies. U.S. agriculture is inextricably intertwined with the national and world economies. Inflation, tax policies, trade barriers, and the value of the U.S. dollar all have an impact on agriculture and influence the profitability of agriculture production practices. A complete discussion of government influence is beyond the scope of this chapter.

The conservation compliance provision and the conservation reserve program of the Food Security Act of 1985 are targeted toward protecting U.S. natural resources. The commodity programs, on the other hand, favor the production of certain crops such as corn and wheat. This leads to higher input use and penalizes farmers for adopting sustainable agriculture rotations.

Regardless of the program, farmers respond to what they perceive to be in their best interest. Some programs provide unintended incentives or disincentives. For example, the current corn price support program rewards past corn production and encourages its continuation (Duffy and Chase, 1989b). These features mean that the more corn there is in the rotation, the higher the reward. However, the more corn there is in a rotation, the more dependent the farmer is on chemical pesticides and fertilizers.

Risk Management

Risk is one of the most important considerations in sustainable agriculture. Risk can be defined and quantified in many different ways. It occurs anytime there is a less than certain outcome. Many kinds of risk are associated with farming, including price and production risks, worker safety risks, genetic risks, consumption risks, and transportation risks.

Farmers must be able to assess the risks of alternative production practices accurately if they are to make informed choices. Everything involves

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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trade-offs, and there is no such thing as a riskless agriculture production system. The goal in sustainable agriculture research and education efforts such as LISA is to understand and reduce the severity of these trade-offs.

Macrolevel Impacts

The macrolevel effects—those beyond the farm—associated with the widespread adoption of sustainable farming systems should also be considered. In the United States there are regional and distributional questions to be answered. Areas with marginal levels of output could be forced out of production. There are international considerations in sustainable agriculture as well. The United States depends on a positive agriculture trade balance to help with the nation's overall balance of trade. U.S. agriculture is tied to the rest of the world through trade and competition. Alternatives must be thoroughly evaluated.

STEPS TOWARD SUSTAINABLE AGRICULTURE

Thus far, this chapter has provided examples of sustainable agriculture research and has discussed the many areas in which more and better information is needed. This section examines some currently available techniques that can move farmers toward sustainable agriculture.

First, however, it is interesting to note two findings regarding farmers and sustainable agriculture. In the Iowa Rural Life Poll, farmers identified the extent to which they used 11 different practices to reduce pesticide or fertilizer use. The practices were soil testing, crop rotation, manure application, mechanical cultivations, planting of legumes, self-scouting, professional scouting, pheromone traps, degree days, tillage, and nonconventional products. Most farmers are currently doing some of the sustainable agriculture practices themselves (Lasley et al., 1990).

Another study was conducted by the U.S. General Accounting Office (1990). In that study, farmers were asked to identify what they perceived to be the barriers to the adoption of sustainable agriculture practices. The top five reasons mentioned by over three-fourths of the farmers contacted were greater management requirements, fear of lower yields, concerns over weed pressure, possibility of lower profits, and the need to maintain base acres.

Most farmers are already using some sustainable agriculture practices, indicating that they are thinking about these agricultural issues. The following six management techniques can help farmers begin to move toward a more sustainable agriculture system immediately.

Step 1 is recognizing fertilizer and yield benefits from rotations and manures. Many studies have estimated the available nitrogen provided by rotations and manure applications, as well as the impact on crop yields.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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Step 2 is performing accurate soil tests and using the results to improve fertility management. A proper representative sample is absolutely crucial. Too often soil samples are not representative. A good soil sample and test from a reputable laboratory shows many things, including the available phosphorus (P) and potassium (K) and the need for lime. Plants need adequate amounts of P and K for efficient production. Plants can utilize P and K from the soil, manure, or other sources. Most Iowa corn farmers follow a P and K application schedule where nutrients are applied in amounts equal to those that the crops remove.

While this seems sustainable on the surface, it ignores the P and K that is already available in the soil. Several studies have shown that beyond certain soil test levels, crops do not respond to added P or K (Webb, 1988). Soil acidity affects many aspects of soil microbiology, soil chemistry, and crop physiology. Maintenance of a proper soil pH can enhance the efficiencies of fertilizers and chemicals.

Step 3 is evaluating tillage trips and methods. Elimination of unproductive trips can improve profitability and enhance sustainability. Farmers must have a tillage plan for each crop and field.

Step 4 is to evaluate alternative production systems. Farmers must continually be receptive to new ideas and techniques. They should look for pieces or parts of systems that can work for their farms. Different economic conditions, different soils, and different managerial skills all indicate the need to continue to search for alternatives.

Step 5 is careful evaluation of chemical applications and application techniques. Farmers need to know the chemicals they are using and the trade-offs of using various chemicals. Price is one discriminating factor. Relative efficacy and ability to control particular pest species are also important. The relative toxicities to humans, animals, and beneficial species, as well as persistence in the environment, also vary.

Application techniques vary in their costs and efficacies. Banded herbicide applications and the use of strictly mechanical controls (such as cultivation) have been shown to be profitable alternatives to the broadcasting of herbicides in many instances (Iowa State Extension Service, 1987, 1988).

Understanding of pest population dynamics and the available alternative techniques must be improved. Pest population monitoring and other integrated pest management techniques have been proven to be effective tools.

Step 6 is the adoption of farming practices based on the available resources. The inherent productivity of the land is often omitted from determining the land's highest and best use. For example, spending $20 an acre for weed control costs $0.40 a bushel for a 100-bushel yield and only $0.27 a bushel for a 150-bushel yield. It is essential to stay within the internal

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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resources of the farm and the farmer. Every manager has strengths and weaknesses. The farming system should accentuate the positive.

There are other examples of currently available practices that support sustainable agriculture. Sustainable agriculture looks at not only better use of existing technologies but also development of new and better technologies—better in terms of profit, social acceptability, and environmental harmlessness.

REFERENCES

Duffy, M. 1988. ISU Farming Systems Project 1987 Start-Up Year: Overview. Ames, Iowa: Department of Economics, Iowa State University.

Duffy, M. 1989a. ISU Farming Systems Project Observations on 1988 Crop Year. Ames, Iowa: Department of Economics, Iowa State University.

Duffy, M. 1989b. Farmers' Attitudes and Opinions Concerning Records and Sustainable Agriculture, Selected Survey Results, Iowa Farm Business Association, 1989. Unpublished paper presented at the Iowa Farm Business Association Executive Workshop.

Duffy, M., and C. Chase. 1989a. Costs and Returns Comparison for Chemical Versus Organic Rotations in Northeast Iowa, 1978–1988. Presented at the Annual Meeting of the Northeast Iowa Growers Association.

Duffy, M., and C. Chase. 1989b. Impacts of the 1985 Food Security Act on Crop Rotations and Fertilizer Use. Staff Paper No. 213. Ames, Iowa: Department of Economics, Iowa State University.

Duffy, M., R. Ginder, and S. Nicholson. 1989. An Economic Analysis of the Rodale Conversion Project: Overview. Staff Paper No. 212. Ames, Iowa: Department of Economics, Iowa State University.

Honeyman, M., M. Duffy, E. Dilworth, D. Grundman, and D. Shannon. 1989. ISU Farming Systems Project. Report No. ORC88-31. Ames, Iowa: College of Agriculture, Iowa State University.

Iowa State Extension Service. 1987. Integrated Farm Management Demonstration Program 1987 Summary Report. Report No. Pm-1305. Ames, Iowa: Iowa State University Extension Service.

Iowa State Extension Service. 1988. Integrated Farm Management Demonstration Program 1988 Progress Report. Report No. Pm-1345. Ames, Iowa: Iowa State University Extension Service.

Lasley, P., and K. Kettner. 1989. Iowa Farm and Rural Life Poll, 1989 Summary. Report No. Pm-1369. Ames, Iowa: Iowa State University Extension Service.

Lasley, P., M. Duffy, K. Kettner, and C. Chase. 1990. Factors affecting farmers' use of practices to reduce commercial fertilizers and pesticides. Journal of Soil and Water Conservation 43(1):132–136.

Padgitt, S. 1985. Farming Operations and Practices in Big Spring Basin. Report No. CRD 229. Ames, Iowa: Iowa State University Extension Service.

Padgitt, S. 1987. Monitoring Audience Response to Demonstration Projects. Baseline Report: Audubon County. Report No. CRD 273. Ames, Iowa: Iowa State University Extension Service.

Suggested Citation:"PART ONE: OVERVIEW." National Research Council. 1991. Sustainable Agriculture Research and Education in the Field: A Proceedings. Washington, DC: The National Academies Press. doi: 10.17226/1854.
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U.S. Department of Agriculture. 1986. Outlook ‘87 Charts. Sixty-Third Annual Agents Outlook Conference. Washington, D.C.: Economic Research Service, U.S. Department of Agriculture.

U.S. Department of Agriculture. 1989. Agricultural Resources, Situation and Outlook. Publication No. AR13. Washington, D.C.: Economic Research Service, U.S. Department of Agriculture.

U.S. General Accounting Office. 1990. Alternative Agriculture, Federal Incentives and Farmers Opinions. Publication No. U.S. GAOI/PEMD-90-12. Washington, D.C.: U.S. General Accounting Office.

Webb, J. 1988. Phosphorus and Potassium Fertilization. Report No. ORC87-13. Ames, Iowa: Northeast Research Center, Iowa State University.

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Sustainable Agriculture Research and Education in the Field: A Proceedings Get This Book
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Interest is growing in sustainable agriculture, which involves the use of productive and profitable farming practices that take advantage of natural biological processes to conserve resources, reduce inputs, protect the environment, and enhance public health. Continuing research is helping to demonstrate the ways that many factors--economics, biology, policy, and tradition--interact in sustainable agriculture systems.

This book contains the proceedings of a workshop on the findings of a broad range of research projects funded by the U.S. Department of Agriculture. The areas of study, such as integrated pest management, alternative cropping and tillage systems, and comparisons with more conventional approaches, are essential to developing and adopting profitable and sustainable farming systems.

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