Sustainable Agriculture Research and Education in the Field A Proceedings (1991) / Chapter Skim
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PART FOUR: RESEARCH AND EDUCATION IN THE NORTH CENTRAL REGION
PART FOUR: RESEARCH AND EDUCATION IN THE NORTH CENTRAL REGION
Pages 229-288
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PART FOUR Research and Education in the North Central Region
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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
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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, 19623.
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EFFECT OF SOIL INSECTICIDES ON CORN ROOTWORM POPULATION DYNAMICS Despite the popularity of soil insecticides and their extensive use over the past two to three decades, limited information is available on the effects of insecticides on corn rootworm population dynamics and corn production. Research on corn rootworms has been focused toward a crop protection mode rather than an offensive mode of pest population management.
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1990. Effect of insecticide treatment on root lodging and yields of maize in controlled infestations of western corn rootworms (Coleoptera: Chrysomelidae)
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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.
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NEED FOR NEW CONTROL TECHNOLOGY FOR CORN ROOTWORMS IN THE CORN BELT Reliance on the prophylactic application of insecticides for corn rootworm control has numerous problems that fall into the following broad interrelated categories. · Use of soil insecticides in corn production systems can add up to $15 per acre in production costs, which may exceed the cost for energy used in corn production.
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, the amount of insecticide residue remaining can be reduced by over 100-fold and, depending on local conditions, may be well below the concentration needed to kill the larvae (Sutter et al., 1989~. NEW MANAGEMENT STRATEGIES FOR CORN ROOTWORMS New approaches to managing corn rootworms must be ecologically compatible with other corn pest management programs.
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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)
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1987. Multi-component kairomonal lures for southern and western corn rootworms (Coleoptera: Chrysomelidae: Diabrotica spp.)
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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~.
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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)
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- ' : a . a'':'''''' Corn Phenology Flowering Dough stage - ''('''''''' - '''' '"'' _ _ `° W~ O ~ X G~Gs GO x GAGE 5\G CONTENTS OF THE BAIT FORMULATION FIGURE 14-3 Effects of bait components and corn phonology on efficacy of starch granule baits against western corn rootworm beetles in field cages.
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The starch granules coo `,, 80 Aged Bait 21 Fresh Bait Field Cage Assay of Bait in situ em: > , 60 In Be 111 C~ 40 ha: o Laboratory Assay of Field-Aged Bait 1 2 3 WEEKS BAITS WERE AGED IN FIELD 2 3 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
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over several growing seasons will begin. The project will involve five states: Nebraska, Iowa, Illinois, Indiana, and South Dakota.
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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.
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1988b. Responses of northern and western corn rootworms to semiochemical attractants in corn fields.
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1989. Effect of insecticide treatments on root damage ratings of maize in controlled infestations of western corn rootworms (Coleoptera: Chrysomelidae)
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In press. Effect of survival, development, fecundity, and sex ratio in controlled infestations of western corn rootworms (Coleoptera: Chrysomelidae)
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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 (19901; an article by J
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Scientists at South Dakota State University initiated a study in 1984 in which they compared a set of conventional and alternative farms in eastcentral 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~.
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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.
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These estimates were needed for the whole-farm economic analyses. At the same TABLE 15-1 Corn and Soybean Yields for Alternative and Conventional Farming, Systems, Lake County, South Dakota, 1985 to 1989 Yield (bu/acre)
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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.
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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.
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. 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 15-33.
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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.
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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.
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Policy Analyses 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.
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, 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)
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On a 700-acre wholefarm 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.
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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.
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1990. Profitability of Alternative Farming Systems at South Dakota State University's Northeast Research Station: 1989 Compared to Previous Transition Years.
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PRINCIPLES OF BEEF PRODUCTION IN THE CORN BELT 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.
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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.
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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.
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· 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.
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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.
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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 16-21. TABLE 16-1 Finishing Performance Input of High-Forage and High-Grain Systems Item High-Forage*
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BREAK-EVEN BEEF PRICES OF ALTERNATIVE SYSTEMS Wintering Systems 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
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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)
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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.
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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.
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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 16-53. TABLE 16-4 Weight Gains During Summer Grazing Weight Gain (lbs)
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Mounds of grain fed per pound of total weight gain achieved from the time of weaning to the time of market. CONCLUSIONS AND FUTURE CHALLENGES Corn Belt farmers can produce cattle competitively by using low-input, soil-conserving, high-forage systems.
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1979. Tillage and crop residue effects on soil erosion in the Corn Belt.
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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.
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This is one of the main reasons that such rotations have been abandoned in conventional farming systems. It is probably even more dramatic in the
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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 sitespecific 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.
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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.
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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.
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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-climateenvironment 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.)
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, 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.
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The goal should be to determine, on the basis of scientific research and on-farm evaluation, what are the best management practices for a given soil-plant-environment system. ALTERNATIVE AGRICULTURE The report Alternative Agriculture (National Research Council, 1989)
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6. As a scientist and former extension specialist, I am concerned about the weak scientific basis for the Alternative Agriculture report.
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1 _ _ 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 Such short-term projects may be scent 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)
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