Sustainable Agriculture Research and Education in the Field A Proceedings (1991) / Chapter Skim
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PART ONE: OVERVIEW
PART ONE: OVERVIEW
Pages 11-106
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PART ONE Overview
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low-input sustainable agriculture (LISA) programs, the Leopold Center at Iowa State University (Ames)
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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.
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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.
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· 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.
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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.
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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.
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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.
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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~.
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1989a. Alternative Agriculture.
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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.
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Congress failed to pass legislation supporting sustainable agriculture research and education. Two reasons for this stand out.
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24 ._ En ~ ~3 _ ~ _ ~ fi z ~ ~ .
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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 lowinput farming.
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, 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.
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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.
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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.
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What proportion of LISA projects deals primarily with organic farming? So far, only about 4 percent.
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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.
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1985. Food Security Act of 1985.
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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.
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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.
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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)
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,~ Photosynthesis \ Biological Control Biological \ Nitrogen Fixation Processes ~ Mycorrhizae \ \~ (Goal) A/// 35 Depletions (net losses)
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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 misdiagnosed, 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
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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~.
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32 34 -12.5 -10.0 m a _ 5 o (D -2.5 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.
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that two slightly different and relatively mild fumigants gave identical releases of ammonium-N, and both delayed Vitrification, 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.
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alternated with winter wheat. Soil fumigation was used as a research tool to determine the full production capability (attainable yield)
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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.
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Washington State College of Agriculture Research Bulletin No.
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In other words, crop rotation is nearly as effective as soil fumigation as a means of achieving the high yields of semidwarf 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.
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invasion and destruction of root hairs, followed by (bottom) a complete stripping away of the root hairs and rootless and discoloration of the cortical tissues of the main roots.
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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.
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The idea that root diseases can be controlled by crop rotation goes back many years.
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With a governmentguaranteed target price and subsidy per bushel of wheat up to the socalled 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.
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1989. Biological control and holistic plant-health care in agriculture.
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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. 1 ~7 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.
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so ~a)
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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~.
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, 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.
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on yields of winter wheat after winter wheat (no crop rotation) in eastern Washington.
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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.
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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.
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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 3-14J. 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~.
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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.
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65.5 (25) 15.6 10.6 NOTE: Fields were cropped repeatedly to wheat (no crop rotation)
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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 TnS 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.
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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.
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1988. Role of phenazinc anEbioCc Tom F~~~ i in biological control of ~e~ ~ var.
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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.
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N nitrogen; IPM, integrated pest management; PKS, phosphorus, potassium, sulfur.
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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.
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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.
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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.
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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)
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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?
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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
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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.
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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 .
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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.
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1974. Biological Control of Plant Pathogens.
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1983. The Nature and Practice of Biological Control of Plant Pathogens.
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1986. Influence of crop rotation and tillage on Rhizoctonia bare patch of wheat.
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Pp. 109-122 in Biological Control of Soil-Borne Plant Pathogens, D
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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.
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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.
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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.
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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.
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81 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~.
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Over time, such practices have also increased susceptibility to soil erosion and hastened loss of soil organic matter.
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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 filth and organic matter from both tillage and erosion since then, productiv
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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 .
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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.
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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.
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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)
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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.
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The Scientific Basis of Alternative Agriculture. Berkeley, Calif.: Division of Biological Control, University of California.
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LISA 88-89. Low-Input Sustainable Agriculture Research and Education Projects Funded in 1988 and 1989.
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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)
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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)
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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)
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, and productive use of crop residue (such as corn stalks) as feedstuffs.
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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.
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The Rodale Research Center uses the term low input to describe their study; pesticides or commercial 10 lo: h m a o ~5 LJ C-C C-Sb C-O-M ENERGY USE _ Produced =1 Used 1=1 Balance FIGURE 5-6 Energy balance from chemical organic demonstration project, 1978 to 1989. Values are average British thermal unit (Btu)
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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1989b. Impacts of the 1985 Food Security Act on Crop Rotations and Fertilizer Use.
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1990. Alternative Agriculture, Federal Incentives and Farmers Opinions.
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