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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS PART FOUR Research and Education in the North Central Region
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS This page in the original is blank.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS 14 New Strategies for Reducing Insecticide Use in the Corn Belt Gerald R. Sutter and David R. Lance Corn rootworms (Diabrotica spp.) are the most serious pests of corn in North America; crop losses and control costs attributed to these pests are estimated to be near $1 billion annually (Metcalf, 1986). Within the Corn Belt, which encompasses 80 percent of the corn acreage in the United States, two species of rootworm, D. virgifera virgifera LeConte, the western corn rootworm, and D. barberi Smith and Lawrence, the northern corn rootworm, are the most important economic pests (Luckmann, 1978). Adults of these species lay their eggs in corn fields in late summer. The eggs hatch the following spring, and the larvae, the primary damaging stage, feed and develop almost exclusively on roots of corn (Branson and Ortman, 1971). When damage to roots is extensive, plant-water relationships are disrupted (Riedell, 1990) and the stability of the plant is reduced. If extensive root pruning coincides with heavy rains and strong winds, plants lodge (tip over), which hampers mechanical harvesting. Although corn rootworms have been pests of corn for over a century (Forbes, 1886), several factors in crop production systems have elevated rootworms to the pest status they occupy today. Most Diabrotica spp. can be managed with proper crop rotation schemes; however, because of production needs, government farm programs, and other economic considerations, crop rotation has not always been a viable option for growers. In fields where corn is grown year after year, extensive use of soil insecticides has resulted because of such factors as (1) the introduction several decades ago of low-cost, presumptively effective soil insecticides, (2) difficulty in predicting damaging pest populations, (3) a prevalent philosophy among soil insect researchers that soil insecticides, like fertilizers, were
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS essential inputs into corn production systems, and (4) promotion by agrichemical industries that their products were the best crop insurance that corn farmers could buy (Turpin, 1977). The dependency on soil insecticides began in the 1950s, when growers began planting corn continuously throughout much of the Midwest and typically applied cyclodiene insecticides to control corn rootworms and other soil pests. Within a decade, resistance to cyclodienes became prevalent among corn rootworms (Ball and Weekmann, 1962). As a result, growers readily switched to organophosphate and carbamate insecticides as they became available for corn rootworm control. There is ample evidence that a high percentage of soil insecticide applications over the past four decades were applied unnecessarily and with limited or no knowledge of the potential of the pest population to produce economic damage (Stamm et al., 1985; Turpin and Maxwell, 1976). Peak usage of soil insecticides in corn production occurred in the late 1970s and early 1980s when 20 million to 30 million acres of corn were treated annually with 1 to 1.3 pounds of actual insecticide per acre (Suguiyama and Carlson, 1985). In 1988, 35 percent of the corn acreage grown for grain was treated with soil insecticides, down from 41 percent in the 2 previous years (Delvo, 1989). Nevertheless, Delvo (1989) projected that of all insecticides used on row crops and small grains in the United States in 1989, 48 percent would be applied to corn, primarily for control of corn rootworm larvae. The insecticides cost up to $15 per acre, which did not include costs for labor or application equipment. Most state extension personnel in the Corn Belt recommend crop rotation for optimal corn rootworm control. However, if growers intend to plant corn in the same field each year, they are encouraged to scout fields for beetles during August. If at any time growers find one or more beetles per plant, they are encouraged to either plant a nonhost crop or use a soil insecticide at planting time the following year. If the trend toward rotating crops in the Corn Belt continues, it would appear that at least part of the corn rootworm problem will be solved. The literature shows, however, that corn rootworms were a problem long before classical insecticides became available and corn was grown in mono-culture. Specifically, alternate-year rotation of corn with a nonhost crop sometimes failed to control the northern corn rootworm (Bigger, 1932; Forbes, 1886). Researchers suspected that beetles migrated to nonhost fields, fed on vegetation, and oviposited, causing infestations the following year. However, recent studies have shown that female northern corn rootworm beetles leave host fields to forage but typically return to corn fields to oviposit (Cinereski and Chiang, 1968; Gustin, 1984; Lance et al., 1989). A more feasible explanation for these infestations was advanced by Krysan et al. (1986). They found that 40 percent of northern corn rootworm eggs were capable of overwintering in the soil for two winters and that the trait was
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS higher in populations from crop production areas that practiced crop rotation. What appears to be a genetic trait in this species places crop rotation as a pest management strategy in jeopardy, particularly when corn and a nonhost crop are planted in alternate years in a rigid pattern. EFFECT OF SOIL INSECTICIDES ON CORN ROOTWORM POPULATION DYNAMICS Despite the popularity of soil insecticides and their extensive use over the past two to three decades, limited information is available on the effects of insecticides on corn rootworm population dynamics and corn production. Research on corn rootworms has been focused toward a crop protection mode rather than an offensive mode of pest population management. As a prime example, the most popular method to evaluate the efficacy of soil insecticides is to remove roots from plots just after larval feeding is completed, visually determine the amount of larval feeding damage, and assign numerical values between 1 and 6 that correspond to levels of root feeding and pruning by corn rootworm larvae (Hills and Peters, 1971). Insecticide efficacy is determined by comparing the numerical values of damaged roots from treated and untreated plots. These values may have little bearing on how an insecticide affects the pest population or protects yield loss (Sutter et al., 1990, in press). In a 4-year study, Sutter et al. (1989) infested field plots with known numbers of corn rootworm eggs per plant and found that the larval feeding damage inflicted at each pest density was consistent each year, but root protection by soil insecticides was highly variable from year to year and among the insecticides tested. Much of the variability was caused by edaphic and environmental conditions. Sutter et al. (1990) recorded consistent percentages of yield loss attributed to damage by corn rootworm larval feeding in untreated plots. Insecticides did not differ in their ability to protect the yield. More importantly, measurable yield protection by insecticides occurred only in plots infested with the higher egg densities; yields in plots infested with low to moderate levels of corn rootworm populations did not differ between treated and untreated plots (Figure 14-1). Correlations between root damage ratings and yields of untreated plants were highly significant, whereas root damage ratings were not significantly correlated to yield in treated plots. This suggests that root damage ratings should not be the only criteria for evaluating insecticide efficacy. These experiments did indicate that all insecticides applied at planting time did reduce root lodging at the high pest densities. Each year, in untreated plots, the amount of root lodging was extensive at the higher pest densities and, thus, would have interfered with mechanical harvesting. Researchers rarely measure the effects of soil insecticides on survival of corn rootworms to the adult stage. As part of the previously mentioned
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS FIGURE 14-1 Ability of soil-applied insecticides to reduce yield loss in corn because of feeding by western corn rootworm (WCR) larvae at several population densities. Source: Data from G. R. Sutter, J. R. Fisher, N. C. Elliott, and T. F. Branson. 1990. Effect of insecticide treatment on root lodging and yields of maize in controlled infestations of western corn rootworms (Coleoptera: Chrysomelidae). Journal of Economic Entomology 83:2414–2420. study (Sutter et al., in press), it was found that reduction in beetle emergence from planting time applications of soil insecticides varied from 16.5 to 81.1 percent (Figure 14-2). Rainfall, as it influences soil moisture, appears to affect pest survival and insecticide efficacy. In 1981, the amount and distribution of rainfall were near normal. Above-normal rainfall was recorded during the larval feeding period (June 10 to July 10) in 1982, and insecticides reduced survival rates in treated plots. Rainfall was below normal in 1985, and insecticides had minimal effects on pest survival rates. Insecticides differed significantly in reducing beetle survival. Water solubility of insecticides, which could affect the movement of the toxin into the soil profile, appeared to influence their effectiveness in reducing beetle survival more than did their inherent toxicity to the larval stage. FACTORS INFLUENCING INSECTICIDE USE IN CORN PRODUCTION SYSTEMS Possibly, the greatest factor that promotes the extensive use of soil insecticides in corn production systems is the lack of reliable pest monitoring
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS technology, more specifically, technology to predict accurately corn rootworm infestations that inflict measurable and significant crop losses that can be translated into an economic injury level (EIL) (Stern et al., 1959). Poston et al. (1983) suggested that EILs are the weakest links in most management programs because these values attempt to oversimplify very complex agroecosystems that may include several pests, variable environmental and agronomic conditions, and different host responses. This scenario typifies corn rootworm management in the Corn Belt. EILs for corn rootworms are based primarily on the amount of feeding damage larvae inflict on the root system; damage levels are then associated with yield differences between treated and untreated plots. The major flaw in this association is that all of the yield differences were assumed to be attributable to stress inflicted by feeding of corn rootworm larvae (Sutter et al., 1990). Research on corn rootworm thresholds has lagged behind similar research on other crops, in part because researchers have concentrated their efforts on insecticide-related questions rather than focusing on basic biological insect-related factors (Turpin, 1974). Methods for sampling all life stages of Diabrotica spp. were recently reviewed in detail (Krysan and Miller, 1986). Most sampling methods are FIGURE 14-2 Emergence of beetles in field plots during three seasons. Numbers over the bars indicate the percent reduction in numbers of beetles in plots treated with soil insecticides. Source: G. R. Sutter, T. F. Branson, J. R. Fisher, and N. C. Elliott. In press. Effect of insecticides on survival, development, fecundity, and sex ratio in controlled infestations of western corn rootworms (Coleoptera: Chrysomelidae). Journal of Economic Entomology.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS cumbersome and costly and have met with little success in corn rootworm pest management programs. Of the methods described, scouting of fields during August and visual counting of beetles on the plants has become the most accepted population-monitoring tool (Tollefson, 1986). However, Foster et al. (1986) concluded from an extensive study in Iowa that the value of sampling corn rootworm adults for predicting economic damage by corn rootworm larvae in the next growing season was low; the optimal strategy for managing corn rootworms in that state, they concluded, was not to sample for adults and always treat corn following corn with a soil insecticide at planting time. NEED FOR NEW CONTROL TECHNOLOGY FOR CORN ROOTWORMS IN THE CORN BELT Reliance on the prophylactic application of insecticides for corn rootworm control has numerous problems that fall into the following broad interrelated categories. Use of soil insecticides in corn production systems can add up to $15 per acre in production costs, which may exceed the cost for energy used in corn production. During most years, a relatively low proportion of the fields in the Corn Belt harbor corn rootworm population densities that warrant treatment. Insecticides used routinely for corn rootworm control are among the most toxic pesticides on the market and carry a high risk of acute toxicity to growers and livestock (Metcalf, 1980). They have also been detected in groundwater and surface water (Williams et al., 1988) and have been implicated in numerous poisonings of wildlife and other nontarget organisms (National Research Council, 1989). In particular, birds are at extreme risk when they forage in fields that have been treated with carbofuran (Environmental Protection Agency, 1985). There is growing concern by farmers of the health risks involved with handling these compounds (McDonald, 1987). Furthermore, most soil insecticides are applied at a time when soils are vulnerable to erosion, particularly in conventional tillage systems, as well as during a season in which rainfall is typically prevalent. Because insecticides are placed in the soil at planting time, their persistence can be influenced by numerous edaphic factors such as soil moisture, degradation by microbial organisms, and differences in physical and chemical properties of soils. These factors cannot be regulated by the grower. Application of soil insecticides at planting time results in the highly inefficient use of resources. At planting time, the actual insecticide concentration in the upper soil profile (1 inch) is between 30 and 35 ppm, which is
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS 100 to 200 times the average 50 percent lethal concentration (LC50) for corn rootworm larvae (Sutter, 1982). Degradation of the parent compound begins almost immediately. By the time corn rootworm larvae are actively feeding on the plant's root system (6 to 8 weeks later), the amount of insecticide residue remaining can be reduced by over 100-fold and, depending on local conditions, may be well below the concentration needed to kill the larvae (Sutter et al., 1989). NEW MANAGEMENT STRATEGIES FOR CORN ROOTWORMS New approaches to managing corn rootworms must be ecologically compatible with other corn pest management programs. If future corn production practices change from the conventional systems used for the past three to four decades to systems that require less input, other pest problems (weeds and insects) likely will emerge. At the same time, emphasis will shift toward the use of nonchemical pest management approaches. For growers to deploy biological control methods for pests other than corn rootworms successfully, they will no longer be able to apply chemical insecticides prophylactically for either larvae or adult corn rootworms without interrupting the delicate ecological balance needed to allow other management programs to function. To reduce the level of chemical dependency that prevails at present in the Corn Belt, development of viable alternative management programs will be required for corn rootworms. It is unlikely that viable strategies can be developed for immature stages of corn rootworms since their habitat is in the soil and they are very inaccessible. Systems to accurately monitor and effectively control these stages have proven to be difficult. Populations of the adult stage, however, can be readily monitored (Tollefson, 1986). The concept of managing corn rootworm populations with adulticides has previously proved effective. Pruess et al. (1974) found that an ultra-low-volume application of malathion (9.7 ounces of active ingredient [AI] per acre) adequately suppressed beetle populations within a 16-square-mile management area and eliminated the need for planting time application of soil insecticides in the following growing season. They found, however, that pest populations rebounded after 1 year because of immigration of gravid females from surrounding areas. These data not only support the concept that corn rootworm can be managed through adult suppression but also indicate that management programs may be most successful if they are applied on an area-wide rather than an individual-field basis. Mayo (1976) applied carbaryl as an adulticide (1 pound of AI per acre) and suppressed beetle populations, on average, by 94.3 percent. Larval feeding damage to plants the following year did not differ from that to plants treated with a soil insecticide. Mayo did observe that carbaryl that was applied to
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS plots often killed insect predators such as lady beetles and lacewings and created an environment for outbreaks of spider mites and other potential pests. Recent advances in knowledge of the chemical ecology of Diabrotica beetles have opened new avenues for the development and deployment of effective management strategies for these pests (Lampman and Metcalf, 1988; Lance and Sutter, 1990). Specifically, attempts have been made to develop semiochemical-based technology for monitoring and, when necessary, suppressing populations of corn rootworm beetles. The latter management tactic involves enhancment of the efficiency of toxic baits by attracting beetles to particles of the bait and inducing them to feed. Semiochemicals affecting Diabrotica beetles have been identified from two sources: the beetles themselves and members of the family Cucurbitaceae, which are ancestral host plants of diabroticites (Metcalf et al., 1980). Female western corn rootworm beetles produce a sex attractant pheromone (8R-methyl-2R-decylpropanoate) that lures males of both the northern and western species (Guss et al., 1984, 1985). The pheromone's usefulness for management programs is limited because it attracts only males and can elicit unusual responses from northern corn rootworms (Lance, 1988a,b). In contrast, compounds that attract beetles of both sexes (but that are more effective for females) have been discovered among squash blossom volatile and related compounds (e.g., see Table 14-1). Rootworm beetles also respond to cucurbitacins, which are tetracyclic triterpenoids that are found in most cucurbits. Cucurbitacins are not sufficiently volatile to act as attractants, but Diabrotica beetles stop and feed compulsively when they touch substrates that contain cucurbitacins. These compounds are very bitter and somewhat toxic to animals that are not adapted to feeding on them (Metcalf et al., 1980). In the summer of 1989, studies were initiated to evaluate and develop the use of semiochemical attractants as tools to aid in monitoring populations of adult corn rootworms. Blocks of traps baited with various amounts of attractants for western (p-methoxycinnamaldehyde) or northern (cinnamyl alcohol) corn rootworms were monitored throughout the season. The resulting data (not yet completely analyzed) will yield information on the relative precision of baited and unbaited traps, optimal levels of attractants for monitoring beetles, seasonal variations in the effectiveness of traps, and seasonal relationships between the number of beetles caught in traps (trap catch) and the deposition of eggs in fields. More comprehensive studies to relate trap catch to beetle population density will be conducted in 1990. Traps that kill beetles with a toxic bait (essentially modifications of the “vial” traps described by Shaw et al. ) are currently being used. Compared with sticky traps, vial-type traps are less messy to handle and capture very few nontarget insects, which makes evaluation easier. Also,
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS TABLE 14-1 Relative Attractancy of Selected Nonpheromonal Attractants for Western and Northern Corn Rootworm Beetles Compound Attractancy of Rootworm Beetle Species* Western Northern Reference† 1. 1,2,4-Trimethoxybenzene 0 (?) 0 (?) 1 2. Indole ++ 0 2 3. trans-Cinnamaldehyde + 0 3,4 TIC mixture‡ +++ + 1 4. Estragole ++ 0 3,5 5. p-Methoxycinnamaldehyde +++ 0 3,4 6. Eugenol 0 ++ 1,6 7. Cinnamyl alcohol 0 ++ 4,7 * 0, not an attractant; +, ++, and +++, slight, moderate, and powerful attractancies, respectively. With sticky traps, powerful attractants often produce 100-fold increases in the numbers of rootworm beatles captured relative to those in unbaited traps. † References: 1, R. L. Lampman and R. L. Metcalf. 1987. Multi-component kairomonal lures for southern and western corn rootworms (Coleoptera: Chrysomelidae: Diabrotica spp.). Journal of Economic Entomology 80:1137– 1142. 2, J. F. Andersen and R. L. Metcalf. 1986. Identification of a volatile attractant for Diabrotica and Acalymma spp. from blossoms of Cucurbita maxima Duchesne. Journal of Chemical Ecology 12:687–699. 3, R. L. Metcalf and R. L. Lampman. 1989a. Estragole analogues as attractants for corn rootworms (Coleoptera: Chrysomelidae). Journal of Economic Entomology 82:123–129. 4, R. L. Metcalf and R. L. Lampman. 1989b. Cinnamyl alcohol and analogs as attractants for corn rootworms (Coleoptera: Chrysomelidae). Journal of Economic Entomology 82:1620 –1625. 5, R. L. Lampman, R. L. Metcalf, and J. F. Andersen. 1987. Semiochemical attractants of Diabrotica undecimpunctata howardi Barber; southern corn rootworm, and Diabrotica virgifera virgifera LeConte, the western corn rootworm (Coleoptera: Chrysomelidae). Journal of Chemical Ecology 13:959–975. 6, T. L. Ladd, B. R. Stinner, and H. R. Kreuger. 1983. Find new attractant for corn rootworm. Ohio Report 68:67–69. 7, R. L. Lampman and R. L. Metcalf. 1988. The comparative response of Diabrotica species (Coleoptera: Chrysomelidae) to volatile attractants. Environmental Entomology 17:644–648. ‡ TIC mixture = equal portions of 1,2,4-trimethoxybenzene, indole, and trans-cinnamaldehyde. attractants can cause sticky traps to become loaded with insects in 24 hours or less, whereas vial-type traps can be designed with a sufficient capacity to be left in place for extended periods of time. Optimal use of semiochemical-based technology for managing corn rootworm populations may require a shift in the size of the management unit.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS ernment programs are primarily developed for grain producers and that the consequences on livestock production are generally ignored. Grain subsidies encourage feeding of grain at the expense of forage utilization. This is not consistent with the goals of sustainability. For example, alfalfa is an excellent crop for use in rotations with corn and soybeans because it adds nitrogen, reduces erosion, and improves soil tilth. Alfalfa production is much less profitable than subsidized grain production is, however. Applied research. A mixture of basic and well-designed applied research is urgently needed to solve today's problems, but it is not being adequately funded. Funding is now out of balance. With the exception of the LISA program, most research funding for forage and beef research is for very basic research (primarily biotechnology). There is a widely held perception that biotechnology will provide a quick fix for all of agriculture's problems through bioengineering of animals or production of a magic drug. The major limiting factor is consistent, good-quality, long-term applied research that will help producers today and that will move the industry toward sustainability. REFERENCES Lindstrom, M. J., S. C. Gupta, C. A. Onstad, W. E. Larson, and R. F. Holt. 1979. Tillage and crop residue effects on soil erosion in the Corn Belt. Journal of Soil and Water Conservation 34:80–82. Smith, G. M., D. B. Laster, L. V. Cundiff, and K. E. Gregory. 1976. Characterization of biological types of beef cattle. II. Post weaning growth and feed efficiency of steers. Journal of Animal Science 43:37.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS 17 Reactor's Comments Low-Input Sustainable Agriculture Projects, Alternative Agriculture, and Related Issues Harold F. Reetz, Jr. This review first comments on the three low-input sustainable agriculture (LISA) projects presented in this section of the volume and then provides some general comments on the workshop on which this volume is based and the report Alternative Agriculture (National Research Council, 1989). THREE NORTH CENTRAL LISA PROJECTS New Strategies for Reducing Insecticide Use in the Corn Belt This review of new strategies for reducing insecticide use by Gerald R. Sutter and David R. Lance emphasized the need to control the corn rootworm, which causes over $1 billion in crop losses annually. They discussed several pest management strategies that offer the potential for reliable control of corn rootworm, while at the same time reducing the use of chemical insecticides. Much of this project is targeted at the management of adult beetle populations as opposed to the common practice of controlling the larvae by applying insecticides to the soil. Crop rotation has been a common method of adult beetle population management. For most Corn Belt farmers, rotation has been the main defense against corn rootworms. By eliminating the host plant from the field where the eggs are laid, the life cycle is broken. Recent studies, however,
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS have shown that up to 40 percent of the rootworm eggs may overwinter for 2 to 5 years, so rotation is not always successful. The use of various attractants to concentrate adult populations, so that insecticides can be applied to a smaller percentage of the total corn acreage, has the potential of greatly reducing the amount of insecticide used. This could greatly reduce insecticide costs for continuous corn systems, and could reduce the potential for environmental contamination from insecticides. New bait systems are under development in which plant-applied insecticides are used at much lower rates compared with soil-applied materials. Many details must be worked out, but the environmental and economic benefits look promising. These studies must be expanded to large field-scale tests to study the true effects on rootworm population dynamics. This will be an interesting project to watch in the coming years. This work is an example of the development of innovations from conventional systems that are helping to make U.S. agriculture more competitive and more sustainable. On-Farm Research Comparing Conventional and Low-Input Sustainable Agriculture Systems This project described in the chapter by Thomas L. Dobbs and colleagues involves an economic analysis of whole-farm crop systems. While the low-input system's livestock component was not included in the analysis, the value of the crop products used in the livestock systems was included in the enterprise analysis. An important philosophy discussed in the review of this project was that whole-farm systems are analyzed to identify specific components that can be studied in greater detail in traditional research projects. These specific studies determine the best management practices for the soil-climate-crop system and the goals and abilities of the manager. The practices thus identified are then applied to the whole-farm system, and the impact on the system is then measured. This approach is important to the development of site-specific management recommendations, which will become increasingly important in crop management in coming years. One problem identified in the analysis was the difficulty in dealing with changes in the crop rotation during the course of the project. This is a common problem in conducting on-farm research, but in a way, it is more reflective of real-world conditions. The low-input case study suffers from low-return crops in the rotation. This is one of the main reasons that such rotations have been abandoned in conventional farming systems. It is probably even more dramatic in the
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS central and eastern Corn Belt, where corn and soybean yields are 50 to 100 percent greater than those obtained in this study conducted in South Dakota. When one adds to that the comparative competitive advantage of producers in the central and eastern Corn Belt for corn and soybeans because of their proximities to markets (domestic and foreign), input sources, and transportation arteries, as well as more favorable climate and soil conditions, it becomes very difficult to see an opportunity for low-input rotation systems to compete with the existing intensive corn and soybean management systems used in the Midwest. The researchers concluded that the low-input system could be made more competitive with conventional systems by adding a premium price to organically grown crops and imposing a 25 percent “tax” on fertilizer and chemical inputs. There are two problems with this approach: Organic premiums would not exist if a large number of farmers adopted the same management system and organically grown crops were readily available to all consumers. Imposition of such a tax on inputs simply for the reason of reducing their use is agronomically unsound and economically unacceptable. Such a policy is tantamount to legislating production practices. It is inconceivable that the political system at the federal or state level can develop an equitable system for determining the appropriate cultural practices (such as fertilizer and chemical application rates) to be used on the wide range of crops-soil-environment-management systems across the country. In fact, more success will be found in working toward the site-specific management approach mentioned above, where fertilizer use is based on detailed soil samples and realistic yield goals, and pesticide use is based on an integrated pest management system, including regular field scouting and combinations of appropriate chemical, cultural, and biological control methods. Overall, the first 5 years of this comparison have provided some interesting data. Better control over the rotation plan will perhaps help improve the comparison in the future. The addition of more farms to the study could be helpful as well. Management system comparisons require many years of study to provide sufficient data to establish the trends and allow for the selection, study, and reintroduction of specific management components. Projects such as this one are a critical part of the research needed to determine which practices can fit into profitable management systems. New practices must first be tested in more intensive research projects, but they should eventually be incorporated into management system comparisons such as the one described by Dobbs and colleagues, so that the overall impact on a farming system can be evaluated.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS Low-Input, High-Forage Beef Production This low-input, high-forage beef production project described by Terry Klopfenstein is a comparison of extensive management versus intensive management systems for beef production. It involves a search for ways to use crop residues as a main component of the beef production system. Grain finishing is still used, but for a shorter period of time. The overall feeding cycle is lengthened, but differences in feeding costs help offset the time efficiency factor. The crop residues that are used are less expensive than conventional forage crops. Corn stalk grazing provides the main roughage component, with alfalfa hay used as a protein supplement. Animal harvesting is used when possible to reduce harvesting costs and labor. This project has the potential to help keep small-scale beef feeding competitive as conventional feedlots are challenged by the swine and poultry industries for grain feeding efficiency. This project is a good example of a cooperative effort between research and extension programs, which are essential elements of maintaining a viable research and extension system. Future Challenges The report concludes that the trend toward high-grain feeding must be reversed if the LISA concepts of this project are to be implemented. This comment presupposes that these concepts should be implemented. That conclusion, like other management decisions, should be made on the basis of research data. The data from this project provide some of that support, but more data are needed. If the high-forage system does prove to be more profitable, it will be adopted. The trend toward high-grain systems has resulted from the fact that they were more efficient. It is not fair to attack university research and extension personnel or cattle producers for their attitude that forage utilization is old fashioned. I have worked with a number of people who consider forages an important part of livestock production and who have developed high-yielding and profitable forage and livestock systems. Grain feeding is also an important part of the crop and livestock management system. The authors state that government policies favor grain production. While this is partly true, there have also been cost-sharing programs that have provided some support for forage production. Government programs for lime, rock phosphate, conservation plans, and several similar government programs have tended to support forage production and make it more profitable. Most of these programs have been terminated, but a few still exist. Alfalfa is an excellent crop for rotation with corn and soybeans, as stated
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS above, and it provides help in controlling erosion, improving tilth, and supplying nitrogen. It is not fair, however, to conclude that alfalfa production would be dramatically increased if grain subsidies were reduced. Alfalfa production must be tied to demand for alfalfa for this system to be viable. A substantial increase in the acreage of alfalfa would destroy the market for those who now depend on alfalfa as a cash crop. There is much more than grain price support programs involved in the overall balance of grains and forages. Regarding applied research, I share the concern that funding for applied research is not in balance with that for basic research. This is also a complicated issue, however. Politically, it is easier to get funding for programs that have quick turnaround times. The issue of accountability and the need to get quick results is a major driving force. Reinforcement of the formula funding program for research and extension would help provide the long-term funding needed for applied research. Perhaps a more critical problem is the system that is in place for evaluating research and extension performance. Scientific publications are the main “measuring stick” for professional accomplishments. Applied research is slow to accomplish and difficult to publish. This makes it unattractive to young scientists who are trying to build a career. Until the recognition of applied research is improved and publication of applied research data is acceptable to the scientific community, this imbalance will continue. Progress is being made, but more is needed. Establishment of a separate research and extension system for sustainable agriculture is not the answer. That would merely establish another bureaucracy that would skim off already limited resources. The change should be made within the existing U.S. Department of Agriculture (USDA) and land-grant research and extension system. Biotechnology is not a quick fix, but there are important gains to be made from biotechnology. The basic versus applied pendulum will continue to swing. Attempts must be made to keep a balance between the two extremes. Both are needed to sustain agriculture as a viable industry. GENERAL COMMENTS I appreciate very much the opportunity to represent the agribusiness community as a participant in this workshop and the opportunity to comment on these projects and the LISA program in general. My training is in crop ecology, and I have always been concerned about protecting the soil and water resources on which the agricultural production system depend. Continued communication and dialogue are essential to help avoid misinterpretation and misunderstanding on all sides of the issues raised by the LISA program.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS The fertilizer and chemical industries have sometimes overreacted to the ideas presented in relation to the LISA program. The industry has been put in a defensive position, however, by many of the LISA-related policy suggestions. Policies proposed under the 1989 Fowler Bill (U.S. Senate, The Farm Conservation and Water Protection Act of 1989), for example, which recommended a 40 percent reduction in pesticide and fertilizer use, are an overreaction to the perceived potential for problems associated with the use of these materials. A whole series of suggestions for the 1990 farm bill proposed by a coalition of environmental advocacy organizations fly in the face of scientific reality. They are based on emotion and philosophy more than on scientific facts. The USDA (including the various research and educational agencies within it) and the National Research Council cannot afford to abandon their long-standing insistence on sound scientific methods in research and sound research evidence upon which to base extension and other education programs. Production practices cannot be effectively legislated. True progress toward a more environmentally responsible, economically sustainable agriculture system will be made only through more site-specific, intensive management systems that attempt to identify and systematically eliminate limiting factors that are holding down productivity or creating potential environmental hazards. These recommendations must be based on solid research information and local experience for the given soil-plant-climate-environment system and for the experience and management ability of the individual farmer and the team of advisers (extension adviser, crop consultant, Soil Conservation Service conservationists, dealers, etc.) who provide technical support. Farmers are good stewards. They depend on their soils and water supplies for their businesses and their families. They depend on their management systems to sustain their businesses. They will not intentionally destroy the resources on which that business is built. Farmers do not intentionally buy excess pesticides and fertilizers. In fact, farmers would prefer to not buy any pesticides and fertilizers. Farmers buy pesticides because they want dead weeds and insects— pests that rob them of their narrow profit margins. When they buy fertilizers, they are buying increased yield potential—increased profitability and quality for the crops they produce. Farmers buy these inputs to the extent—and only to the extent—that they can expect to improve the profitability of their farming operations. Terms such as satanic pesticides and synthetic chemical fertilizers have been used by some of the speakers at this symposium, but they are inaccurate and cause the uninformed listener to develop misleading impressions of the pesticides and fertilizers used by farmers and of the industries that
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS produce them. Increasingly, they cause consumers to fear for the safety of the food supply, when, in fact, the United States has the safest, most highly regulated, and lowest-cost food supply in the world. The fertilizers commonly used on U.S. farms are naturally occurring nutrients that undergo a minimum amount of processing to make them more easily handled for uniform application and more readily soluble for most efficient use by growing crops. Fertilizers merely supplement the natural supplies of the same nutrients in the soil and replace the nutrients that are removed by the harvested crop. COMPETITIVE GRANTS Charles Hess and others have expressed support for expanding the funding for competitive grants under the 1990 farm bill. Such grants give an opportunity to fund projects that will provide quick turnaround, provide information to supply the need for accountability in the political arena, and support the pressures for scientific publications within university and USDA promotion systems. These are all important goals. A strong level of support for the long-term research programs on traditional subject areas such as soil management, plant breeding, and crop nutrition must be maintained, however. In these subject areas, answers come slowly because researchers are dealing with climatic variabilities that can mask real treatment differences, or because several generations of materials must be evaluated to make progress. These processes take time. They do not produce instantaneous or exciting results. They do provide, however, the basic information and technological developments that must continue to serve as the framework on which the new technologies of genetic engineering, biotechnology, computer simulation, and other high-technology projects can be tested and implemented. Since the mid-1970s, I worked closely with the late Herman Warsaw, the world-record corn producer (370 bushels/acre in 1985), as he developed a crop management system that not only broke yield records but also revitalized a badly eroded, low-productivity farm. By rebuilding high fertility levels, Warsaw was able to grow increasingly higher yields, which returned increasingly large amounts of crop residues to the soil. (University of Illinois and Purdue University research has shown that for each additional pound of grain produced, a corn crop produces an additional 1 pound of aboveground stover and up to 0.75 pound of roots. This ratio holds fairly constant throughout a yield range from 100 bushels/acre to over 300 bushels/acre.) Thus, when Warsaw chisel-plowed his corn residue, leaving one-third of it on the surface, he was leaving the equivalent of the residue from an average corn yield on the surface to control erosion, while turning under
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS twice that amount of plant material to help build soil structure, organic matter, and overall tilth. People like Herman Warsaw challenge their fellow farmers and researchers to look for the limiting factors in their own production systems. Small-plot research and demonstration studies are needed to test new ideas. Then, these ideas must be incorporated into mainstream farming systems to measure their impact and potential for widespread adoption. Whether high yield or low input is the goal, the research procedures are the same. A low-input research and extension program is not needed. Continued support for existing research and extension programs is needed so that they can test the low-input alternatives along with conventional practices. Then, the alternative practices that prove to have merit can readily be moved into mainstream production channels. For the past 25 years, the Potash & Phosphate Institute has promoted maximum economic yield (MEY) crop production. During the 1980s this was a major thrust of its research and educational programs. Determination of the maximum potential yield for a given site is an important first step. This is done with small-plot research. Then, economic analysis is used on small-plot and field-scale tests to determine the MEY level. The goal is to improve profits, but to do so in a way that is agronomically sound, economically efficient, and environmentally responsible. MEY is low-input per unit of output. MEY is efficient, profitable, and sustainable. In the end, MEY production systems and sustainable agriculture production systems may not be much different. The goal should be to determine, on the basis of scientific research and on-farm evaluation, what are the best management practices for a given soil-plant-environment system. ALTERNATIVE AGRICULTURE The report Alternative Agriculture (National Research Council, 1989) has stimulated much discussion and attracted much attention since it was released in the fall of 1989. The report contains a great deal of information about farming systems and their potential impact on the environment and the economic viability of U.S. agriculture. The report has also raised some serious concerns that must be addressed: Major changes in production systems must be based on science. The report states that research is lacking in many of the subjects discussed. The LISA projects described in this volume are a step in the right direction, but too much of the report is based on emotion and philosophy and not enough is based on research. The environmental problems mentioned in the report are not well documented. Most are actually isolated cases of accidents or mismanagement.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS Reading of the report by the public and news media interpretations of it have caused undue concern among the general public about the safety of the U.S. food supply. As stated earlier, U.S. consumers enjoy the safest, most abundant food supply in the world—and at very low cost. The report implies that manure and legumes are environmentally benign sources of nitrogen (N). Researchers throughout the Midwest have shown that legumes and manure may actually be more likely to release N at a time when it is highly susceptible to leaching, denitrification losses, or both. N fertilizers can be more readily controlled for rate and timing of application. This does not mean that legumes and manures are not a valuable source of nutrients, but careful attention to management details is required for their most efficient use. Erosion is presented in the report as being a serious threat, which is true. Replacement of chemical weed control with mechanical cultivation can lead to increased erosion, however. Well-fertilized crops develop better root systems and more total dry matter, which help improve the permeability and water-holding capacity of the soil. Below-maintenance fertilizer applications result in reduced biomass production and lead to a greater potential of erosion. Robert Klicker's discussion (this volume) on the importance of high fertility for maintaining erosion control and profitability in wheat production in the Palouse area of the Northwest is a good example, as is the system of high-yield corn production developed by Herman Warsaw in Illinois. Low-input systems generally reduce root development and total dry matter production. This is not sustainable. As a scientist and former extension specialist, I am concerned about the weak scientific basis for the Alternative Agriculture report. The prestige and integrity of the National Academy of Sciences, National Research Council, and USDA are threatened by some of the conclusions presented without sound scientific basis. As an extension specialist—and as an industry agronomist—I have always insisted on the use of sound research as the basis for promoting changes in production practices. I cannot maintain my integrity as a scientist unless I demand the same from the LISA program. INTERGRATED CROP MANAGEMENT PROGRAM Charles Hess reported (this volume) on the initiation of a special program of the USDA Agricultural Stabilization and Conservation Service, known as the SP53 Integrated Crop Management Program. This pilot program was designed to determine the effects of reducing pesticides and fertilizers by 20 percent on a group of 100 farms in each state. The concept of a categorical reduction of inputs by 20 percent without a scientific basis (pest scouting, soil tests) is philosophically wrong. In fact, that approach is an insult to the research and extension programs and agribusiness efforts
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS that have been directed toward the development of integrated crop management systems. As stated earlier, production practices cannot be effectively legislated. A better approach would be to use consultants as provided in the protocol, but use them to evaluate a farm's needs and make sound recommendations specifically designed for a given farm. Fertilizer applications and pest management decisions must be more site specific and must be based on detailed local field data from soil survey, soil testing and plant analysis, and pest scouting. It is also unlikely that the 3-year duration of the program is sufficient to evaluate the effects of reducing inputs. Such short-term projects may be sufficient to evaluate a component, but as has been shown in the South Dakota project reported in this volume (see the chapter by Thomas Dobbs and colleagues), farming systems projects are long-term studies. The intent of the SP53 Integrated Crop Management Program may be different from the initial program of implementation. There is still time to make it workable. ARE THE VARIOUS GROUPS REALLY AT ODDS? The fertilizer and chemical industries depend on a viable, profitable, sustainable agriculture system. I am not at odds with the LISA program 's overall goals of sustainable production systems. The problem lies in the ideas on how to reach those goals and how we define sustainable. In fact, the problem really lies in the ability and willingness of the various groups to communicate with each other. Agriculture has a poor image among the general public—either as a wasteful, irresponsible, environmentally destructive industry or as the farm couple in Grant Wood's portrait, American Gothic. Neither of these is an accurate portrayal of the technically advanced, business-oriented, environmentally conscious farmer of today who will be the farmer of the twenty-first century as well. I do not apologize for my involvement in the high-yield research and education programs in universities and industry that have helped make the United States the low-cost producer of high-quality food, fiber, and energy products that it is today. I do not ask environmentalists to apologize for their concern that society should strive to protect soil, air, and water resources. Our goals are compatible. Let's all work together to keep U.S. agriculture number one in the world—sustainable agronomically, economically, and environmentally. REFERENCE National Research Council. 1989. Alternative Agriculture. Washington, D.C.: National Academy Press.
Representative terms from entire chapter: