Sustainable Agriculture Research and Education in the Field: A Proceedings (1991)

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

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

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.

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

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.

Possibly, the greatest factor that promotes the extensive use of soil insecticides in corn production systems is the lack of reliable pest monitoring

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.

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.

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

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 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

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. [1984]) 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,

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.

Corn rootworm control decisions are currently made on a field-by-field basis (e.g., Foster et al., 1986; Stamm et al., 1985). To be effective, monitoring systems require accurate forecasts of future economic losses in individual fields. Unfortunately, even the most precise trapping data, as with data from visual counts, are probably not suitable for this purpose (Foster et al., 1986). Unpredictable variables such as weather and shifts in soil biota strongly affect crop losses by influencing, among other factors, survival of eggs over the winter, establishment of neonates in the spring, effects of feeding damage on yield, and when applicable, efficacy of soil insecticides (Gustin, 1981; Sutter et al., 1989). An alternative strategy is to use larger management units. Monitoring systems would be used to identify crop areas that produce corn rootworm population densities that, if not reduced, potentially could infest much broader areas. Control measures could then be directed at these “source” areas early in the season before beetles emigrate to surrounding fields. Although thresholds for suppression would remain somewhat arbitrary, an area-wide management system such as this could theoretically result in substantial reductions both in rootworm populations and in the amount of acreage treated for rootworms. Such a system, however, would require an effective and environmentally sound means of suppressing adult rootworms.

Semiochemical-based baits for suppressing rootworm beetles are currently being developed. The system that is envisioned will contain four categories of components. The first component is an agent to kill the beetles. Most studies to date have used carbamate insecticides such as methomyl or carbaryl, although other insecticides or other types of agents (e.g., growth regulators and pathogens) may eventually be used. With carbamates, 0.1 percent toxin in the bait produced substantial mortality of beetles (Lance and Sutter, 1990; Metcalf et al., 1987), but somewhat greater amounts (0.3 to 0.5 percent) are probably more practical if baits are to remain active for extended periods in the field (Lance and Sutter, 1990).

The second bait component is a feeding stimulant. Metcalf et al. (1987) clearly demonstrated that rootworm beetles readily feed upon and ingest a lethal dose of edible substrates that contain less than 0.1 percent cucurbitacins. In more recent studies, unpurified powdered root of the buffalo gourd, Cucurbita foetidissima H.B.K., has been added to bait at 5 percent of total dry weight. This powder contains about 0.5 percent cucurbitacins E, I, and E-glycoside (Metcalf et al., 1982), so again, the total bait is less than 0.1 percent cucurbitacins. Cucurbitacins are not only effective feeding stimulants, but because they are distasteful to nonadapted animals, they should tend to deter nontarget organisms from feeding on the bait.

Bait components in the third category are volatile attractants which, theoretically, will lure beetles to individual point sources of bait or from untreated portions of cornfields into treated portions (see Table 14-1).

Finally, the first three types of components are formulated into a carrier that can be consumed by beetles. Various carriers have been tested, including granules of bitter cucurbit fruit, corn grits (Metcalf et al., 1987), cereal-based flakes (D. R. Lance and G. R. Sutter, unpublished data), cereal-based pellets, and granules of cross-linked corn starch (Lance and Sutter, 1990). The starch granules have been studied most extensively; they are both palatable to beetles and effective at slowly releasing volatile attractants (Meinke et al., 1989).

Field tests of semiochemical-based toxic baits have been hampered somewhat by the mobility of the beetles. Movement of beetles between fields can mask the effects of baits in small experimental plots, and testing of baits on a large scale has not been feasible because of economic and legal considerations. To circumvent these problems, many aspects of bait performance were evaluated in walk-in cages (10 by 10 feet) containing corn plants that were treated with various bait formulations. Western corn rootworm beetles were released into the cages, and survivors were counted by using removal sampling after 24 to 72 hours, depending on the test.

In field cage tests in 1988 (Lance and Sutter, 1990), starch granule baits that were applied at a rate of 8 pounds per acre (equivalent to 0.6 ounces of carbaryl per acre) produced approximately 85 percent mortality of beetles in 24 hours (Figure 14-3). The cucurbitacins (feeding stimulants) appeared to be the key semiochemical component that enhanced the efficacy of baits in field cages. Baits that consisted of only the starch carrier plus carbaryl did not measurably affect survival, and within the limits of the field cage, addition of equal portions of 1,2,4-trimethoxybenzene, indole, and trans-cinnamaldehyde (TIC) as attractants (see Table 14-1) to baits did not improve the efficacy over that of granules containing only carbaryl and cucurbitacins. In 1989 field cage studies, the attractant, again, did not influence the efficacy of bait, even though a range of concentrations of attractants was tested and the bait particles were spaced farther apart than they were in the 1988 tests (unpublished data).

One of the initial concerns about bait performance was whether the particles could compete with naturally occurring sources of food. Specifically, an abundance of highly preferred food, such as green silk and fresh corn pollen, is available to beetles when corn is flowering; for many management purposes, bait should be applied during or soon after this period. The phenological effects on the efficacies of baits were tested by running field cage trials simultaneously in flowering corn and corn in the “dough” or “dent” stage (i.e., more mature) corn. In several such tests (e.g., Figure 14-3), the baits demonstrated their ability to compete favorably with highly preferred natural foods.

In 1989, several small (2- to 7-acre), partially isolated plots of field corn in eastern South Dakota were treated. The bait that was used was supplied

FIGURE 14-3 Effects of bait components and corn phenology on efficacy of starch granule baits against western corn rootworm beetles in field cages. CARB = 0.5 percent carbaryl; CUCS = about 0.03 percent cucurbitacins; TIC = 1.5 percent TIC attractant (equal portions of 1,2,4-trimethoxybenzene, indole, and trans-cinnamaldehyde). Source: Data from D. R. Lance and G. R. Sutter. 1990. Field-cage and laboratory evaluations of semiochemical-based baits for managing western corn rootworm beetles (Coleoptera: Chrysomelidae). Journal of Economic Entomology 83:1085–1090.

by a private cooperator and contained 0.3 percent carbaryl, 5 percent powder of buffalo gourd root, and 0.5 percent of the TIC attractant in a flaky, cereal-based carrier. The bait was applied at about 8 pounds per acre; carbaryl, then, was applied at about 0.4 ounces per acre, which was a 98 percent reduction compared with conventional control procedures. In most cases, the bait produced substantial reductions in the populations of beetles in the plots (Figure 14-4). Unfortunately, the effectiveness of the bait was short-lived, and immigration into treated areas typically caused beetle populations to rebound within a week after treatment. This result was somewhat unexpected because bait that was aged in the field for a week showed a

high level of activity when it was assayed in the laboratory (D. R. Lance and G. R. Sutter, unpublished data). By 48 hours after treatment, however, almost all of the small (14-mesh or less), flaky particles of bait appeared to have been blown or washed from the corn plants, which is where the beetles spend most of their time. In a field cage study (D. R. Lance and G. R. Sutter, unpublished data), the bran-based bait produced over 90 percent mortality of beetles in 48 hours when it was sprinkled carefully on corn plants but did not produce any measurable mortality when it was broadcast on the ground. Thus, the position of the bait in the field appears to be very important. Currently, work in conjunction with several U.S. Department of Agriculture and private cooperators is being performed to develop a formulation that sticks to corn plants. Still, a different dry formulation (the starch granules) did not show such a rapid loss of efficacy in the field compared with that in laboratory assays (Figure 14-5). The starch granules

FIGURE 14-5 Effects of aging starch granule, semiochemical-based baits for 1, 2, or 3 weeks in the field on mortality of western corn rootworm beetles relative to mortality of beetles that were not exposed to bait. Source: Data from D. R. Lance and G. R. Sutter. 1990. Field-cage and laboratory evaluations of semiochemical-based baits for managing western corn rootworm beetles (Coleoptera: Chrysomelidae). Journal of Economic Entomology 83:1085–1090.

were more dense than the cereal-based bait and tended to collect and remain in the leaf axils, silk, or other relatively protected areas on the plants (unpublished observations).

Another advantage of semiochemical baits that contain low concentrations of a toxin such as carbaryl is the relatively low mammalian toxicity of the insecticide compared with that of chemicals currently being used for managing diabroticites (Table 14-2). Furthermore, because the application rate of toxin is reduced in the baits by 98 percent, for example, the comparative toxic exposure to nontarget vertebrates would be greatly reduced.

There is currently a request, through a private cooperator, for an Experimental Use Permit from the U.S. Environmental Protection Agency (EPA). When the permit is granted, regional pilot-scale tests of bait formulations in production fields (80 to 160 acres in size) over several growing seasons will begin. The project will involve five states: Nebraska, Iowa, Illinois, Indiana, and South Dakota. Protocols for evaluating this management concept have been established to evaluate the system across these geographical areas uniformly. Factors to be investigated include overall efficacy of baits (reduction of beetle densities and oviposition and determination of how reductions affect plant protection the following growing season), optimal application patterns, influence of attractants on efficacy, effects of bait on nontarget organisms, and comparisons of bait technology with conventional methods of managing corn rootworm populations. A regional approach to

field testing of this concept is essential. The baits must be tested under a variety of agronomic and environmental conditions; moreover, their effectiveness must be demonstrated locally before transfer of this technology to growers will be successful.

In view of the growing concern over the use of agrichemicals in the Corn Belt, this project can make a major contribution to the improvement of pest management programs. The concept, if proven successful, could be extended to other diabroticites that affect a variety of crops, primarily vegetables. The ultimate result of this innovation could be a very significant reduction in the amount of insecticide applied and the resultant environmental damage and human health risks.

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Thomas L. Dobbs, James D. Smolik, and Clarence Mends

The search for answers to questions about the economic, agronomic, and environmental sustainability of alternative agriculture systems requires multidisciplinary teamwork by groups of scientists, using a whole-farm perspective (Dobbs and Taylor, 1989; Madden and Dobbs, 1990). Farmers and public policymakers need much more information than is currently available on the agronomic performance, profitability, and riskiness of low-input sustainable (alternative) farming systems compared with those of more conventional systems. Information is needed on how systems compare under different agroclimatic and farm policy conditions. This information is best generated through two concurrent lines of inquiry: (1) studies involving operating farms and (2) studies based on research station trials. Neither type of study alone will suffice at the present stage of sustainable agriculture research.

Most economic studies of alternative farming systems based on research station trials are in the very early stages. An exception is that reported by Helmers et al. (1986), based, at the time, on 8 years of experimental results in Nebraska. Duffy and Nicholson (1987), Goldstein and Young (1987), and Dobbs et al. (1988) have reported economic results based on research station trials for shorter periods of time in Iowa and Pennsylvania, Washington, and South Dakota, respectively. South Dakota's experiment station research is now further along, and baseline economic results for a 5-year transition period (1985 to 1989) have been reported by Dobbs and Mends (1990); an article by J. D. Smolik and T. L. Dobbs recently submitted to the Journal of Production Agriculture contains detailed yield results for the transition period, as well as results of sensitivity analyses with economic variables.

Perhaps the most widely known studies of operating farms are the case studies in the National Research Council report Alternative Agriculture (National Research Council, 1989). A variety of other on-farm studies have recently been initiated with support from the U.S. Department of Agriculture's low-input sustainable agriculture (LISA) program and the Northwest Area Foundation.

Scientists at South Dakota State University initiated a study in 1984 in which they compared a set of conventional and alternative farms in east-central South Dakota. This study has provided the agronomic and economic data needed to systematically compare two operating farms using contrasting systems over the past 5 years (1985 to 1989). These two farms are located in the transition zone between the corn-soybean growing region of the Midwest and the small-grain growing region of the northern Great Plains. Thus, a wide variety of foodgrain, feedgrain, and oilseed crops are grown in this region. None of the case studies presented in the National Research Council (1989) report represented agricultural practices in the northern Great Plains, and there is a need for information that sheds light on the comparative productivity and profitability of conventional and alternative farms in that region. Policymakers, in particular, are unsure how certain proposed farm program revisions might affect the profitability of, and therefore the adoption of, alternative agriculture systems in that region. Results of this ongoing case study, which is being conducted by a multidisciplinary team of plant scientists and agricultural economists, are therefore timely.

Through a series of surveys, case studies, and policy analyses supported by the Northwest Area Foundation, researchers at South Dakota State University are gaining a detailed understanding of sustainable agriculture practices in different crop regions of South Dakota (Dobbs et al., 1989; Taylor et al., 1989a,b). Detailed analysis of yields and economic performance for the pair of farms reported in this chapter was supported by grants from the U.S. Department of Agriculture (USDA) LISA program. Analysis of these two farms has interpretive value in its own right; moreover, the analysis has enabled the development of methodology that is being adapted and used in other South Dakota case studies. The present analysis of two case study farms will be placed in the context of a larger set of case studies in South Dakota later in 1990.

Agronomic data were collected over a 5-year period for two farms, one that uses an alternative agriculture system and one that uses a conventional agriculture system, in Lake County in east-central South Dakota. The topography in the study area is gently rolling. The climate is continental,

with a 7-month growing season (April to October), and the long-term average growing season precipitation is 19.68 inches.

Crop acreage on the conventional farm ranged from 317 to 998 acres over the 5-year study period (1985 to 1989). The farm is basically a cornsoybean operation in which these two crops are alternated every other year on most fields (except for farm program set-aside acres). The farm also has a small cow-calf operation, in which the calves are finished on the farm, and a hog-finishing operation, from which approximately 1,000 hogs are marketed each year. Commercial fertilizers (primarily nitrogen and phosphorus) and herbicides are used each year on the conventional farm, and corn is cultivated at least once each year. In recent years, soybeans have been drilled in narrow rows and, therefore, have not been cultivated. The conventional farmer has not been using a moldboard plow. An all-in-one soil finisher (involving disk, field cultivator, and harrow) is the conventional farmer's principal implement for soil preparation before planting.

The amount of land cropped on the alternative farm ranged from 537 to 900 acres over the 5-year period studied. The principal rotation is a 4-year system consisting of a small grain overseeded with alfalfa-alfalfa-soybeanscorn, in that order. Small-grain crops normally consist of some combination of barley, oats, and spring wheat. Alfalfa is harvested as hay only 1 year before it is chiseled. On average, during the study period, 50 percent of the crop acreage was in alfalfa and small grains (including farm program set-aside acres, generally with a small-grain cover crop), and the other 50 percent was split roughly equally between corn and soybeans. At the time that agronomic data collection started (1985), the alternative farm had not applied any commercial fertilizers or herbicides for the previous 8 years. Land continued to be farmed that way during the study period, but moderate amounts of commercial fertilizers and herbicides were used on some newly rented land coming into the alternative farm's system. Most of this farm's cropland qualifies as organic under the certification standards being used in South Dakota and nearby states.

The alternative farm has a farrow-to-finish hog operation involving 40 to 50 sows. The operator of this farm also finishes a few cattle and is in the process of rebuilding the cattle portion of his operation. A small portion of some of the alternative farm's fields receive light applications of composted manure from the livestock operations; however, over the 5-year study period, less than 5 percent of the fields were treated with manure. The alternative system relies primarily on legumes (alfalfa and soybeans) for nitrogen.

The inclusion of alfalfa in the rotation also helps control weeds. Rotary hoeing, harrowing, hand weeding, and cultivating are also important weed control measures in row crops (corn and soybeans) on the alternative farm. The moldboard plow is not being used in the alternative system.

Yield data and soil samples were collected from areas within fields with Egan soil associations (fine-silty, mixed, mesic Udic Haplustolls; slopes, 0 to 6 percent). Egan soils are deep and well drained and have medium to high fertility. Row crop yields were estimated by hand harvesting 10 randomly selected 3-foot lengths of row. Soil samples were collected in late September-early October, and 8 to 10 subsamples were collected from each plot area. Samples for the alternative system were obtained from fields that had not received commercial fertilizer or herbicides for at least the previous 8 years. Yield and soil test data were statistically analyzed by using years as replications.

Corn and soybean yields varied considerably from year to year (Table 15-1). Although the alternative system had higher average yields for corn and the conventional system had higher average yields for soybeans, the differences between the alternative and conventional systems were not significant (p > 0.05). An earlier study (Lockeretz et al., 1978) conducted in the Midwest also found no significant differences in corn and soybean yields between organic and conventional farms.

The alternative farmer was asked in early 1989 to recall his small-grain and alfalfa yields for the years 1985 through 1988, and he was asked to estimate his 1989 yields of those crops following harvest that fall. These estimates were needed for the whole-farm economic analyses. At the same

times, both the alternative and conventional farmers were also asked for their estimates of whole-farm average yields for corn and soybeans in each of the years 1985 through 1989. These yield estimates, which were not limited to the Egan soil portions of the two farms, were as follows when averaged over the 5-year period: alternative corn, 82.6 bushels/ acre; conventional corn, 97.2 bushels/acre; alternative soybeans, 25.4 bushels/acre; and conventional soybeans, 36.0 bushels/acre. These farmer-estimated whole-farm average yields were all lower than the hand-harvested average yield estimates for Egan soils on the two farms. Moreover, the farmer-estimated corn yields on the alternative farm were lower than the farmer-estimated corn yields on the conventional farm, whereas the alternative system corn yields were higher than those of the conventional system when estimates were made by hand harvesting. The corn yield differences were not statistically significantly (p > 0.05) in either case, however. Farmer-estimated soybean yield estimates for the alternative and conventional farms did differ significantly (p < 0.05).

Three factors might explain why the farmers' estimates of yields were less than the estimates obtained by hand harvesting: (1) the greater efficiency of hand harvesting, (2) the exclusion of lower-yielding knolls and low-lying areas from areas that were hand harvested (these landscape positions were excluded because they did not contain Egan soil associations), and (3) the farmers may not have accurately recalled all of their yields and may have tended to be conservative in their estimates.

For purposes of comparing conventional and alternative farming systems, the use of yield estimates obtained by hand harvesting (rather than estimates made by the farmers) for the row crops on the better (Egan) soil areas has the effect of eliminating a possible source of bias caused by different soil properties on the two farms that are unrelated to the choice of a conventional or an alternative management system. Therefore, the economic analysis reported in this chapter is based on the yields (for row crops) obtained by hand harvesting.

Soil nitrate and potassium levels during the fall did not differ significantly (p > 0.05) between the two systems (Table 15-2). The lack of differences in nitrate levels between the two systems suggests that the rotation pattern in the alternative system resulted in adequate levels of nitrogen fixation. Soils in the study area are naturally high in potassium. Phosphorus levels were significantly higher in the conventional system; however, no symptoms of phosphorus deficiency were observed in the alternative system. Organic matter was significantly higher in the alternative system (Table 15-2). Higher levels of organic matter in low-input sustainable agriculture systems were also reported in previous studies (e.g., Lockeretz et al., 1978; Sahs and Lesoing, 1985).

Crop enterprise budgets were developed for the two case study farms, and the budgets were aggregated to whole-farm bases, taking into account available acreage and farm program provisions for each year of the study. Thus, the acreage devoted to each crop and to set-aside acres varied from year to year, depending on farm program provisions and each farmer's cropping decisions. Sometimes, one or both farmers participated in optional paid diversion programs for corn. In the baseline analysis, premium prices for organically certified crops were ignored. Crops were valued each year by using the higher of the applicable (1) average market year prices estimated for South Dakota or (2) federal loan rates for eastern South Dakota; applicable federal deficiency payments for each qualifying crop were then added. Thus, year-to-year variations in federal farm program provisions and market prices, in addition to variations in weather and yields, affected whole-farm gross returns. For purposes of valuation, it was assumed that all hay was sold; hay was valued on the basis of estimated market prices in South Dakota for each year. Thus, at this stage of the analysis, livestock have not been integrated into the economic analysis. Explicit integration of livestock into the whole-farm analysis will take place in late 1990. Input prices were held constant over the study period in the analysis.

Five-year average results of the baseline economic analysis for the alternative and conventional farming systems are given in Table 15-3. The first two columns of data show various cost and return measures on a per acre basis. Gross income calculations were based on the corn and soybean yields reported in Table 15-1 and on yields for other crops (mainly the alfalfa and small grains of the alternative farmer) reported by the farmers themselves. The same cost and return measures are shown on a whole-farm basis in the fourth and fifth columns of data, assuming that there were 700 tillable acres on each farm. Each farm actually had an average of slightly over 700 tillable acres (i.e., acres available for crops, including hay, and farm program set-asides) over the 5-year period. The first whole-farm net income figure (return over all costs except land, labor, and management) is one indication of the earnings available for family living expenses, taxes, and savings for a family-owned and -operated farm in which all farm labor is provided by the family. In arriving at the third net income figure (return over all costs except management), all labor, including family labor, was calculated at the going local wage rate, and a rental value or opportunity cost of the land was also subtracted from the gross income. Any additional net income attributable to livestock operations (to be calculated in the next stage of analysis at South Dakota State University) could be added to family income, as could off-farm income earned by family members.

Direct costs (sometimes referred to as operating or cash costs) were $39/ acre higher on the conventional farm than they were on the alternative farm ($85/acre compared with $46/acre) (Table 15-3). This difference was largely due to the fertilizer and herbicide inputs on the conventional farm. Gross income on the conventional farm ($216/acre) was $50/acre higher than that on the alternative farm ($166/acre). Thus, the higher gross income on the conventional farm more than offset that farm's higher direct costs. Although average corn yields were slightly higher on the alternative farm (Table 15-1), the heavy concentration of corn and soybeans in the conventional farm's rotation, together with higher soybean yields on that farm, caused the conventional farm's gross income to be higher.

Before accounting for land, labor, and management costs, the conventional system showed net income that averaged $15/acre more than that of the alternative system ($103/acre compared with $88/acre). Because the alternative farm required 58 percent more labor than that required on the conventional farm, when all labor was included in the costs, the difference increased from $15 to $19/acre (see net income over all costs except land and management in Table 15-3).

Both systems provided positive net returns to management (see net income over all costs except management in Table 15-3), on average, and in

each of the 5 years studied (Table 15-3 and Figure 15-1). Only in one year (1988) did the alternative farm have higher net returns than the conventional farm.

When each farmer's own whole-farm yield estimates, rather than the estimates obtained by hand harvesting, for corn and soybeans were used in the analyses, differences in net income in favor of the conventional farm were increased substantially. For example, the difference of net income over all costs except management was increased from $19 to $29/acre. Using farmer-estimated yields, the alternative farm experienced net losses (negative net returns to management) in 2 of the 5 years, whereas the conventional farm experienced no such losses.

The crop return calculations underlying the results for the alternative farm shown in Table 15-3 were based on the assumption that all production was marketed conventionally. In actual practice, most of the alternative farm is operated without purchased chemical inputs, and a portion of the production (mainly soybeans) normally goes into markets for organically produced products that bring premium prices (“organic premiums”).

FIGURE 15-1 Net income comparison over time: income over all costs except management, 1985 to 1989.

The impact of organic premiums on the net returns of the alternative farm was analyzed by using four different combinations of assumptions about the portion of the soybean crop that went into organic markets and the magnitude of the price premium for the organically marketed portion. These assumptions were derived from experiences reported by organic farmers in South Dakota (Taylor et al., 1989a). The combinations of assumptions about soybeans, ranging from conservative to optimistic, were as follows: (1) option B, 50 percent marketed organically at a 25 percent price premium over the price for conventionally produced soybeans; (2) option C, 70 percent marketed organically at a 25 percent price premium over the price for conventionally produced soybeans; (3) option D, 50 percent marketed organically at a 40 percent price premium over the price for conventionally produced soybeans; and (4) option E, 70 percent marketed organically at a 40 percent price premium over the price for conventionally produced soybeans. Additional cleaning is required for a crop that is marketed organically, so it was assumed that each harvested bushel of crop results in 0.90 bushel on an organically cleaned basis. Calculations were carried out on a whole-farm basis, recognizing that soybeans constitute just one part of the alternative system rotation. Whole-farm analyses were carried out for each year of the 5-year study by using the combinations of assumptions listed above.

Results are shown in Figure 15-2 in terms of 5-year averages for net income over all costs except management per acre. The baseline (no organic marketing) case for the alternative farm ($41/acre) is given on the left, and the conventional farm comparison ($60/acre) is given on the right. Each of the organic marketing sensitivity analyses added $1 or $2/ acre, on a whole-farm basis, to the net income for the alternative farm. The most optimistic option tested for all 5 years (option E) left the average net income for the alternative system ($48/acre) lower than that for the conventional system, however.

Another analysis (not shown in Figure 15-2) was carried out for the alternative farm in 1989 only, because more detailed information was available for the alternatives farm 's organic marketing that year. In that year, 42 percent of the soybean crop was actually marketed at a 77 percent premium over the conventional price, and 29 percent of the oats crop was actually marketed at a 190 percent premium over the conventional price. Incorporation of these organic amounts and premiums resulted in net income over all costs except management (on a whole-farm basis) of $75/acre that year (Table 15-4) compared with $58/acre when the premiums were ignored (baseline; see Figure 15-1). Thus, in some years, the actual organic premiums can result in higher income for alternative than for conventional farms under the conditions of this study. Whether organic premium prices can remain as high as those observed in 1989, however, remains to be seen.

FIGURE 15-2 Effects of adding organic premiums in the alternative system: income over all costs except management, 5-year average.

Extensive policy analyses have begun under South Dakota State University 's sustainable agriculture research grant from the Northwest Area Foundation. However, results of only two types of these analyses are reported here.

The first policy analysis presented represents a 25 percent increase in purchased chemical fertilizer and herbicide input prices. This could result from a significant tax on these inputs, which conceivably could be implemented to discourage their use by internalizing the possible external costs associated with chemical input use. Thus far, special state taxes on chemical fertilizers and pesticides generally have been set at rates that are quite low. These state taxes raise some revenues for research and education on input use, but the tax rates are probably too low to directly discourage the use of inputs. It is possible that stiffer taxes will be used in the future to discourage chemical input use, however. Developments in world petroleum markets also could push chemical input prices up significantly in the future. This would have the effect of increasing fuel costs as well; however, fuel costs were not increased in the analysis reported here.

When chemical input prices were increased by 25 percent, the 5-year

average of net income over all costs except management decreased by only $1/acre (from $41 to $40/acre) for the alternative farm, because chemicals (in limited quantities) were used on only a portion of that farm. On the conventional farm, however, average net income for the 5-year period decreased by $9/acre (from $60 to $51/acre). Chemical input price increases of this magnitude do not appear to be sufficient, by themselves, to equalize the net returns for the two types of farming systems. However, the higher chemical input prices, together with organic premiums for some of the products of the alternative farm, could be sufficient to bring net returns of alternative systems close to or higher than those of conventional systems.

The second policy analysis presented here consists of a 25 percent reduction in federal farm program target prices for corn and small grains in the years 1985 through 1989. Since there has been much discussion of possible further reductions in target prices, the effects of hypothetically lower target prices during the past 5-year period were calculated. Starting with the baseline figures (no organic premiums), net income over all costs except management decreased by $17/acre (from $41 to $24/acre) on the alternative farm and by $19/acre (from $60 to $41/acre) on the conventional farm as a result of setting target prices 25 percent lower than their actual levels in each of the past 5 years (Figure 15-3). The adverse effect was greater, in

FIGURE 15-3 Effects of reducing federal target prices by 25 percent: income over all costs except management, 5-year average.

absolute terms, on the conventional farm, as expected, but by only a slight amount ($2/acre). As a percentage of net income, the effect was greater on the alternative farm, however; there was a 41 percent decline on the alternative farm and a 32 percent decline on the conventional farm.

The policy analyses and interpretations for these two case farms were still in progress at the time of preparation of this chapter. Hence, caution must be used in drawing conclusions at this point. Nevertheless, it is clear that, at present, both alternative and conventional farms in the northern Great Plains depend a great deal on government programs for their economic sustainability. Both farms benefited from government payments in such forms as deficiency payments, payments for optional paid acreage reductions (including participation in the “0-92” program), and amounts by which government commodity loan levels exceeded market prices in some years. These payments averaged $27 and $33/acre over 5 years for the alternative and conventional farms, respectively. On a 700-acre whole-farm basis, the government payments averaged $18,900 for the alternative farm and $23,100 for the conventional farm. The payments were 16 percent of the average gross income and 66 percent of the average net income for the alternative farm, and they were 15 percent of the average gross income and 55 percent of the average net income for the conventional farm.

This on-farm research case study found conventional farming to be more profitable, on average, than alternative (low-input sustainable) farming in an area of east-central South Dakota when price premiums for organic products were ignored. In this paired comparison, corn and soybeans averaged 83 percent of the conventional farm's crop land acreage compared with 49 percent of the alternative farm's acreage. For the alternative farm, an average of 20 percent of the acreage was in harvested small grains (barley, oats, and wheat) and 16 percent was in alfalfa. (The remaining cropland of each farm was in various forms of paid and unpaid acreage set-asides.) Given the combination of crop prices and federal farm program provisions that were in effect from 1985 through 1989, it appears to have been difficult for rotation systems containing substantial small-grain and forage legume acreage to have been fully competitive with systems that were heavily dominated by corn and soybeans. Organic crop price premiums, when available to qualifying alternative farms, could have reduced and perhaps, in some cases, eliminated the net return difference, however.

Case studies now under way for farms in other crop regions in South Dakota may give different results about comparative profitability. A whole-farm economic analysis based on experiment station trials at South Dakota State University's Northeast Experiment Station (Dobbs and Mends, 1990)

showed that alternative systems are more economically competitive with conventional systems than did the case farm analysis reported here. The Northeast Experiment Station, where those trials were conducted, is in an area with somewhat lower average rainfall and a shorter growing season than in the east-central county, where the case study farms discussed here are located. Consequently, small grains constitute a greater portion of the conventional rotations on farms near the Northeast Experiment Station than was the case for the conventional case study farm reported here. It appears that the greater the role of small grains in conventional crop rotation systems, the more likely are alternative (low-input sustainable) systems to be economically competitive with those conventional systems, at least with the current federal farm program.

There is a need for more extensive analyses of various farm program options on the relative economic competitiveness of conventional and alternative farming systems. Some such analyses are currently under way by South Dakota State University and Washington State University agricultural economists.

Matters other than on-farm profitability are also relevant to public policy regarding alternative agriculture. For example, the implications of different types of farming systems for the economic health of rural communities and regions are important; these implications will receive attention over the coming year in studies at South Dakota State University. Environmental externalities related to the chemicals that are used in different types of systems also need greater research attention to provide bases for the development of public policy. When contamination of groundwater may be related to a particular farming system, for example, public policies may need to either internalize such costs or provide positive incentives to farmers to shift to more environmentally benign systems. Farming systems that erode the soil resource base, as evidenced by the reduced organic matter content and the need to purchase nutrients in conventional systems, sometimes may be more profitable in the short term but very well may not be sustainable from a long-term environmental perspective. Even when water quality and other environmental concerns weigh heavily on the development of policies toward alternative agriculture, it is crucial for empirical information to be available regarding the impacts of policy options on the economic profitability (and, therefore, the economic sustainability) of farms that use conventional versus alternative farming systems in different agroclimatic regions. Experiment station and on-farm studies such as the one reported here constitute the principal source of such information.

Research on which this paper is based received support from the South Dakota State University Agricultural Experiment Station, U.S. Department

of Agriculture Low-Input Sustainable Agriculture grants LI-88-12 and LI-89-12, and Northwest Area Foundation grant 88-56.

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Dobbs, T. L., D. L. Becker, and D. C. Taylor. 1989. Farm Program Participation and Policy Perspectives of Sustainable Farmers in South Dakota. Economics Staff Paper No. 89–7. Brookings: South Dakota State University.

Duffy, M., and S. Nicholson. 1987. Two of Iowa's low input agriculture research programs. Presented at Symposium on Current Economic Prospects for Sustainable Farming Systems, American Agricultural Economics Association Annual Meeting. American Journal of Agricultural Economics 69:1067 (Abstract).

Goldstein, W. A., and D. A. Young. 1987. An agronomic and economic comparison of a conventional and a low-input cropping system in the Palouse. American Journal of Alternative Agriculture 2:51–63.

Helmers, G. A., M. R. Langemeier, and J. Atwood. 1986 An economic analysis of alternative cropping systems for east-central Nebraska. American Journal of Alternative Agriculture 1:153–158.

Lockeretz, W., G. Shearer, R. Klepper, and S. Sweeney. 1978. Field crop production on organic farms in the Midwest. Journal of Soil and Water Conservation 33:130–134.

Madden, P., and T. L. Dobbs. 1990. The role of economics in achieving low-input farming systems. Pp. 459–477 in Sustainable Agricultural Systems, C. A. Edwards, R. Lal, P. Madden, R. H. Miller, and G. House, eds. Ankeny, Iowa: Soil and Water Conservation Society.

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Sahs, W. W., and G. Lesoing. 1985. Crop rotations and manures versus agricultural chemicals in dryland grain production. Journal of Soil and Water Conservation 40:511–516.

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Terry Klopfenstein

The trend in the beef industry has been to raise large cattle with faster body weight gains. This method requires high-grain feeding (including corn silage, which is half grain)—a type of cattle production that is incompatible with the forage resources available on many farms in the Corn Belt.

The low-input sustainable agriculture (LISA) project on which this chapter is based is a study of low-input systems of beef production. These systems emphasize the use of animal-harvested (grazed) forages (pasture, range, cornstalks, and other residues consumed in the field) in place of supplemental feeds (such as soybean meal, grain, and other mechanically harvested or purchased feeds) to reduce costs and increase profits. The purpose of this study is to examine ways to optimize the use of crop residues produced in cropping sequences and forages, especially legumes, which supply nitrogen to the soil at a lower cost and minimize soil erosion.

This study is based on the principles that use of forages and manure can reduce input costs in agricultural production systems and that forage production in cropping systems can greatly reduce soil erosion. Because of their ability to utilize forages, beef cattle fit into farming systems that are based on forage production and manure utilization.

Much of the land in southern Iowa, northern Missouri, and eastern Nebraska is subject to erosion. However, a large percentage of the land in this region can be used for crop production (with appropriate tillage and management practices), and the resulting crop residues can be partially removed

without causing excessive soil erosion (Lindstrom et al., 1979). In addition, most farms have some land that should not be tilled; it is suitable only for pasture. The challenge of this study is to integrate economical beef production systems with the available forage resources.

Analysis of data collected from beef producers in Iowa and Nebraska shows large differences in feed costs among producers. Producers who rely more heavily on grazed forages and, consequently, who incur reduced expenditures for off-farm purchases of supplements had significantly higher profits. Better management of forages and careful attention to reducing input costs will be necessary in the future to keep production costs down and to ensure the profitability of systems that reduce soil erosion and ground-water contamination.

Just as the combinations of forage and grain that can be used to feed growing-finishing cattle are numerous, variations in cattle types have also increased dramatically in the past few years. Extremes have been observed, from heifers that weigh from 800 to 1,000 pounds (lbs) at low Choice grade to steers that weigh from 1,300 to 1,400 lbs at the same grade and degree of fatness. Recognizing the growing consumer preference for leaner meats, the packing industry has moved rapidly to provide boxed beef at the low Choice grade with an acceptable carcass range of 600 to 900 lbs.

The feeding system interacts with cattle type to produce various carcass weights at the low Choice grade. Cattle with similar growth potentials that are grown on roughages before they are finished on grain are older when they are sent to market (low Choice grade) and have heavier carcasses. This is because they have developed farther along their growth curve and because they have attained more skeletal and muscle growth before they are fattened.

While the sizes of mature beef cattle have increased, the feed efficiencies of cattle taken to the same degree of fatness probably have not increased (Smith et al., 1976). Efficiencies of feed conversion are primarily affected by the composition of the weight gain rather than by mature weight. Therefore, the current trend to try to produce “uniform” cattle is not really necessary. It is important, however, to match the feeding system to the cattle type, to produce cattle with acceptable weights at the low Choice grade. As a generalization, for animals with smaller frames (mature size), more roughage should be fed to avoid overfinishing (too much fat) at an acceptable carcass weight.

It is more difficult to meet the market requirement of low Choice grade combined with yield grade 1 or 2. The correlation of external fat to marbling (intramuscular fat) is quite high. Grain is fed to cattle to fatten them. The desirable fat is marbling, and outside fat is wasteful. Producers can make cattle as lean as they desire without the use of growth promoters or repartitioning agents simply by feeding them more roughage and less grain.

However, no sure method currently exists to produce low Choice yield grade 1 or 2 cattle consistently.

The beef industry is also facing a critical economic challenge. One problem is competition from lower-cost meats, primarily poultry and pork. Although promotion may sell more beef, especially in the short run, it seems that cost of production must be reduced if the beef industry is to remain competitive and profitable. The ultimate goal of beef production systems is to produce a product that is suitable to meet market demand while using the available resources in an environmentally sound way and at a price sufficient to encourage further production and consumption.

Because of their ability as ruminants to utilize large quantities of fiber, cattle are competitive with other meat-producing species only when they are fed forage. The trend of the beef industry has been in the opposite direction in the past 30 or more years, with more grain being fed (including that in corn silage). It seems that the beef industry can go in two primary directions: high-grain or high-forage systems of production.

In the high-grain system, calves would be placed on high-grain rations after an adjustment period of approximately 30 days postweaning. This system best fits large-frame (large mature size) steers, bulls, or both. It is important to note here that these cattle will reach the necessary fatness for the Choice grade with body weights that are 50 to 200 lbs lighter than those of the same cattle grown in a high-forage system. The smaller size is an advantage for the high-grain system, because the carcass weights will not exceed the standards of the beef packers, and therefore, the price will not be discounted. A disadvantage is that less beef is marketed per cow, and therefore, the basic cost of raising the animal must be covered with fewer pounds of beef. The primary advantage of the high-grain system is the rapid and efficient rate of weight gain, which reduces interest on invested input costs and the daily feedlot yardage costs. The use of some corn silage in place of grain in this system does not reduce feed costs because the price of silage is based on the price of the grain in the silage.

The following are some principles for designing beef production systems:

• Animal harvesting of feeds by grazing is economical. If the costs of fuel, equipment, and labor increase in the future, this will be even more economical.

• Crop residues are less expensive to produce than are conventional forages because the cost of production (land, fertilizer, etc.) is charged against the grain. Admittedly, harvesting costs may be high for crop residues, but conventional forages must be harvested as well, and the cost may be nearly as great.

• Grasses should primarily be grazed, not harvested. Some harvesting may be needed to provide winter forage and supplemental needs.

• There will be a premium on lean growth in beef cattle, but there is no premium for fat.

• Beef cattle should be finished on grain so that they have an acceptable amount of fat to meet current grading standards and market demands and, therefore, so that a profitable market price can be obtained.

• Cattle raised in high-forage systems make excellent compensatory weight gains during the early stages of finishing.

Because the market requires that beef carcasses be in an acceptable weight range, cattle used in high-forage systems should be heifers of large-or small-framed breeds or steers of smaller-framed (British) breeds. About 40 percent of the cattle fed in feedlots are heifers. In addition, many British breed steers are produced from young (first and second calf) cows, even if exotic terminal cross (large-framed) sires are to be used in later parturitions. Therefore, over half of the beef animals produced in the future would be expected to have frame sizes that are compatible with high-forage systems.

The team conducting this study includes researchers and extension specialists from Nebraska, Missouri, and Iowa. The disciplines represented on the study team include beef nutritionists, agronomists, and agricultural economists. Cattle producers from the three states serve as consultants on the project.

Eight extension scientists are members of the project team. In addition to their input into the research, their most significant contributions will be in information dissemination. The research findings will be reported in cattle reports that are published by each state, and at least one field day will be held each year in each state in conjunction with the ongoing research. In addition, a three-state symposium was held on June 13 and 14, 1990, for producers and extension personnel in the three-state area. A publication will be prepared in the future for agent training and producer meetings. The primary target audiences are agricultural extension agents, U.S. Soil Conservation Service personnel, and farmers-cattle producers, particularly those who have marginally productive, highly erodible soils. Many of these producers will earn increased profits from these forage-based beef production systems. An additional expected benefit is greatly reduced water pollution and soil erosion.

In Missouri, the first objective will be to determine whether summer annuals can be planted into fall fescue grass sod by the no-till method. This information is needed because of the need to convert fungus-infested tall fescue pastures to fungus-free cultivars. The second objective will be to

compare winter grazing of stockpiled tall fescue grass (allowed to grow tall without grazing or mowing) versus drylot feeding of hay as they relate to subsequent weight gains by steers. To optimize the utilization of forages, low-cost alternatives to winter feeding, such as grazing of forage that is stockpiled during the fall, should be associated with improved management of cattle in the pastures in summer. Cattle often do not gain weight at high levels during winter grazing of relatively low-quality forage, but they grow rapidly (known as compensatory growth) during the spring, when high-quality forage becomes available. Therefore, a period of spring grazing should be used in a beef production system so that the low-cost gain as a result of compensatory growth can be captured by the beef producer. The study will determine the efficacy of growing calves on stockpiled forage and the use of high-quality wheat pastures to accomplish compensatory growth in calves during the spring.

In Iowa, the project team is developing cow-calf production systems that maintain beef cow reproductive efficiency with minimal use of hydrocarbon fuels. Different systems of grazing of summer pastures composed of grass or grass-legume mixtures are being studied. Fall and winter feeding systems will compare grazing of crop residue and minimal hay supplementation with feeding of hay ad libitum (allowing the animals to eat as much as they want) to cows on drylots.

The following findings are based on the research that has been conducted and completed in Nebraska.

An accounting model was developed to aid in understanding biological and economic relationships and to study the impact of variations in resource costs on net returns earned through different beef production systems. The model compared production costs and break-even prices of cattle placed on high-grain finishing diets immediately after weaning with those of cattle grown on forage diets prior to finishing. Two types of experiments were conducted to establish a biological basis for the model. The first type of experiment compared high-grain versus high-forage growing-finishing systems. The second evaluated the effect of the rate of weight gain in winter on total system performance.

Each year for 3 years, calves from 136 British breed cows and Charolais bulls born in the spring were weaned at an average age of 187 days and were used to evaluate the two systems. After an initial 30-day period to allow adjustment to weaning, the cattle were allotted randomly to either a

high-grain system, in which they were placed directly into the feedlot for finishing on a 90 percent grain diet, or to a high-forage system, in which they were grown on forage diets prior to finishing (Table 16-1). Cattle in the high-grain system were adjusted to the finishing diet in 21 days and were then fed for an additional 185 days. Cattle in the high-forage system were wintered on crop residues (165 days), grazed on summer pasture (115 days), and then finished in the feedlot (122 days) in the same manner as cattle in the high-grain system were.

Eighty mixed British breed steers (20 head per system per year) averaging 520 lbs were used each year for 2 years to evaluate wintering systems. These trials had two objectives: (1) to determine what level of performance could be expected with different wintering systems and (2) to establish three different levels of weight gain during winter to evaluate the effect of the rate of weight gain during winter on subsequent performance. Three rates of weight gain during winter were used: 0.62, 0.84, and 1.1 lbs/ day. Averages of 2 years of data were used. After wintering (106 days), cattle were grazed on summer pasture (116 days) and then were finished in the feedlot (122 days).

Across both years, six different wintering systems were evaluated. These wintering systems used harvested crop residues supplemented with different levels of supplemental protein and alfalfa hay, as well as cornstalk grazing supplemented with harvested crop residues and protein supplement or alfalfa hay (Table 16-2).

The rate of winter weight gain used in the model was dependent on the particular wintering system selected. The research findings indicate that the rate of weight gain during winter negatively affected the subsequent rate of weight gain when the cattle grazed on pasture. The prices of corn and alfalfa hay are important elements of the model. The cost of supplemental protein is linked to the price of corn. Specifically, the price of soybean meal was calculated as 2.4 times the price of corn on a weight basis for the 10-year average relationship. The prices of all other protein sources were based on the price of soybean meal on an equal cost per unit of protein. The cost of corn silage was based on the price of corn.

Systems 1 and 2 were designed to produce two levels of weight gain by increasing the level of supplemental protein. Cattle wintered through system 2 gained 0.46 lb/day more than those in system 1, but their break-even

costs were higher by $0.65/100 lbs of gain (Table 16-3). This result occurred because of the cost of the increased weight gain during winter and the associated reduction in compensatory weight gain made on grass in system 2 compared with that in system 1.

The systems that used cornstalk grazing (systems 4, 5, and 6) were the most feasible, as long as they did not require large amounts of supplemental protein. This was due to the lower cost of cornstalk grazing compared with that of feeding harvested feedstuffs. Wintering feedlot yardage fees were included to cover the costs of facilities, labor, and management. These costs were $0.15 lower for cattle wintered on cornstalk fields compared with those for cattle wintered in drylots, thereby giving an additional advantage to the cornstalk grazing systems. Alfalfa proved to be an excellent protein and energy supplement for cattle wintered on cornstalk fields (system 6).

Total weight gain in the forage phase of the system was affected only slightly by the wintering phase. Therefore, expenditures for inputs to increase performance during winter were not profitable. Reductions in wintering yardage costs or other fixed costs were advantageous, while any added costs for extra performance during the winter were not.

The break-even beef price was lower for the high-forage system than for the high-grain system, except when the price of corn was very low relative to the prices of the other inputs. The extended feeding period required by

the high-grain system (189 versus 112 days) implies that twice as much corn (or other grain) was required. However, because of the increase in size and compensatory growth potential, cattle in the high-forage system consumed more feed per day when they were placed on a finishing ration. They gained weight faster, but were less efficient in terms of weight gain per pound of grain (Table 16-1). Nonetheless, the price of corn had only a small effect on the comparative economic efficiency (break-even price) of the high-grain system versus that of the high-forage system (Figure 16-1).

Increasing interest rates increased the break-even price faster for the forage system than it did for the high-grain system (Figure 16-2). This was due to the need for a greater total investment and the longer time period required for the high-forage system. This effect was not large, however. For example, an increase in the interest rate of 5 percent with the high-input system increased the break-even price by only $2.49/100 lbs. Likewise, the differences in break-even beef prices because of the purchase price of feeder cattle were small and favored the high-forage system.

In general, cattle on feeding systems that increased weight gain during winter through higher inputs (between 0.62 and 1.1 lbs/day) were found to have decreased weight gains during summer. Since weight gain during winter required higher costs than did weight gain during summer, an increase in wintering costs decreased the economic feasibility of the system,

FIGURE 16-1 Effect of price of corn and finishing systems on final break-even price.

FIGURE 16-2 Effect of interest rate and finishing systems on final break-even

as reflected in the higher break-even price of beef. Changes in corn prices and interest rates had relatively small effects on the comparison of high-grain versus high-forage feeding systems, even though total interest costs were higher for the high-forage system. The greatest benefit of high-forage systems is increased total production per animal unit. This increased product diminishes the average fixed cost of the feeder calf and, along with other efficiencies, yields a lower break-even price than that obtained with high-grain systems. Cattle finished after being grown on high-forage diets gained weight much faster, but they consumed almost as much total grain as those that were finished immediately after weaning. Forage systems can produce more total beef at a lower cost per unit of product, except in times of very low grain costs relative to the costs of other inputs (interest, feeder cattle, etc.) or high wintering costs.

Since it was observed that the cattle fed in the high-forage system made about 57 percent of their weight during high-grain finishing, the study was

expanded to include the objective of increasing the amount of weight gain made while the cattle were on pasture. Ninety-six steer calves were used in this research, which was initiated on October 19, 1988. The calves grazed cornstalks from October 19, 1988, through March 1, 1989. They received different protein supplements, thus providing the opportunity to evaluate low-input supplementation with alfalfa or inexpensive by-products. The calves were then fed ammoniated wheat straw until May 3, 1989, when they were moved to brome pastures. Methods of increasing weight gain were (1) use of Sudan grass for summer pasture, (2) supplementation with bypass protein (protein that bypasses digestion in the rumen but is digested in the small intestine) and an ionophore (a feed additive that enhances the efficiency of fermentation in the rumen), and (3) extension of the grazing period until November 20, 1989.

Calves gained 0.95 lb/day while grazing cornstalks and 0.55 lb/day when they were given the ammoniated wheat straw. They gained 1.85 lbs/ day when they were given brome until June 27 and gained 0.6 lb/day more if they were fed the supplement. Because of the drought during the period of this research, the cattle required more acres of pasture than normal, and they had better than normal weight gains on the brome from June 27 to September 4, 1989 (2.16 lbs/day). Cattle on the Sudan grass gained 2.35 lbs/day during that period, and none of these cattle responded to the supplement (data not shown). Overall, weight gains during summer were increased by the supplement (Table 16-4). The cattle that remained on the brome regrowth gained 2.38 lbs/day from September 4 to November 20, 1989.

On September 4, 1989, two-thirds of the cattle entered the feedlot and were finished in 101 days. They gained 4.08 lbs/day, and feed conversion was 6.4 (Table 16-5). The remaining one-third of the cattle that entered the feedlot on November 20, 1989, gained 3.40 lbs/day for 94 days at a feed conversion of 8.7. Break-even prices of these cattle were about $6.00 to $13.00/100 lbs better than those of the cattle in the high-grain system, that is, those that were finished on grain immediately after weaning ( Table 16-5).

Corn Belt farmers can produce cattle competitively by using low-input, soil-conserving, high-forage systems. The management needed in this system is very intensive, however. It is relatively easy to put cattle in a feedlot and feed them corn. It is much more difficult to manage cattle that are grazing cornstalks when fields are muddy or covered with snow. It is a major challenge, even to the most capable livestock manager, to maximize gains on summer pasture while working around droughts and other forces that constantly change the amount of feed (grass) available. It can also be done economically, however, and in a manner that conserves soil, enhances the environment, and is sustainable.

The trend in the beef cattle industry has been toward high-grain feeding. The preliminary findings of this LISA project are contrary to that trend. However, several constraints limit adoption of high-forage systems:

1. Cattle producer attitudes. Compared with high-grain systems, forage utilization has the image of being old-fashioned and not progressive. University researchers and extension personnel frequently share this attitude; they are partially responsible for the attitudes of producers that use of grain is the only way to feed cattle. Major changes in attitudes are required to increase forage utilization.

2. Government policies favor grain production. It is amazing that gov-

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.

3. 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.

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.

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).

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,

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.

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

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:

1. 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.

2. 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.

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.

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

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.

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.

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

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.

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

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.

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:

1. 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.

2. The environmental problems mentioned in the report are not well documented. Most are actually isolated cases of accidents or mismanagement.

3. 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.

4. 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.

5. 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.

6. 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.

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

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.

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.

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