NORTH CENTRAL REGION
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|Planting crops into 4 to 8-inch ridges helps farmers reduce the amount of herbicides they spray to control weeds. |
Photo by T.L. Gettings/Rodale Institute.
In the mid-1980s, producers seeking ways to conserve soil without sacrificing yields or profits began to look at ridge tillage. Some farmers wanted to combat erosion. Others desired an alternative to reduce the fuel and machinery maintenance expenses associated with the several tractor passes required for conventional tillage.
First developed in the 1950s, ridge tillage features minimum soil disturbance. Farmers plant their crops into four- to eight-inch ridges, and the soil remains undisturbed from harvest to the next planting. During the production season, ridge-till farmers control weeds with cultivation and minimal use of herbicides.
Ridge-till proponents tout its environmental and profitability advantages over conventional tillage, which requires three to five tractor passes to prepare the seedbed--compared to ridge till's one or two. Ridge till also goes hand-in-hand with "banding" herbicides for weed control, offering farmers the opportunity to dramatically decrease chemical application by concentrating spraying on the ridges rather than on the entire field.
While interest was high, producers lacked the real-farm management information they needed to abandon traditional tillage systems. They worried the conservation tillage technique would not provide as good a seed-bed as deep tillage had.
"As sustainable agriculture gathered momentum, people began to combine practices and technologies in new ways in the search for sustainable cropping systems," says Rick Exner, who in 1992 received a SARE grant to conduct on-farm research and demonstration of ridge tillage. "We had pieces before that, but we didn't really have systems."
Over four years, 29 farmers working in tandem with university researchers conducted more than 140 replicated on-farm trials involving ridge tillage and ways it could be incorporated into working production systems. Their research provided an information base and demonstration sites for farmers and researchers, becoming a much-needed focal point from which producers could learn how to adapt ridge tillage to specific, on-farm situations.
Unlike many traditional models where university scientists conduct research at experiment farms under controlled conditions, the project's trials were designed and conducted by farmers, many of them affiliated with Practical Farmers of Iowa (PFI).
PFI, a nonprofit, farmer organization, encourages on-farm research of profitable, environmentally sound agricultural practices. Many of its members raise corn and soybeans that, in the past, required extensive tillage. Researching and demonstrating ridge tillage was a good fit for many of the farmers, who wanted to investigate how to grow such crops with ridge tillage and realize its potential benefits. Specifically, they wanted to learn about various methods of fertilizer placement, cover crops and other factors that would help make their systems more environmentally sound without giving up profits.
"A lot of sustainable agriculture is management critical," Exner says. "If you want to find the potential of a system, you have to go where the practitioners have the management skills to make it work."
The SARE grant helped provide the farmers the opportunity to develop ridge tillage-related practices, measuring their success through replicated field comparisons. The ridge-till trials also attracted several ISU scientists, who extended those studies through their own research. When Exner and the farmer-researchers examined the results of four years of research, they found:
Ridge till compares very favorably with other tillage systems for yields while lowering cost of production. While more management-intensive than other systems, it proved to be very profitable on a per-acre basis.
Ridge till is compatible with frugal use of herbicides, including eliminating it altogether, reducing rates through banding and alternative measures such as rotary hoeing, cover cropping and cultivation.
Ridge till offers more weed management flexibility than no-till, letting producers integrate more sustainable practices and limiting the need for "rescue" herbicide treatments.
Even though spring release of soil nutrients is delayed in ridge till, the practice is compatible with the pre-sidedress soil nitrate test used for corn in Iowa and some other states.
Information learned through the PFI and SARE on-farm ridge tillage research continues to contribute to the development of more sustainable systems. Today in Iowa, ridge tillage has gained favor by those sustainable farmers producing organic and herbicide-free soybeans, which garner premium prices $3 to $10 higher than regular soybeans in the world market.
"Individually, we've all satisfied some of our goals and doubts by what we've looked at and learned," says Ray Stonecypher of Floyd, Iowa, one of the farmer participants.
Stonecypher studied ridge tillage with and without herbicide, with different nitrogen rates, with dry and liquid fertilizer and with different equipment modifications, and learned he could reduce his herbicide and fertilizer use while maintaining yields.
One of the best aspects of the project was developing solutions in concert with university researchers, says Richard Thompson, who examined potassium uptake and how the use of ridge tillage facilitated more sustainable rotations as part of the project. Thompson of Boone, Iowa, remains a national leader in ridge tillage and on-farm research.
Perhaps most important, the project allowed producers to establish communication ties with other farmers around the state interested in trying ridge tillage innovations, lessening the pressure associated with "being different" in the local farming community.
By its very design, ridge tillage makes on-farm research more inviting to farmers, Exner says, because the ridges facilitate row identification and marking and make it easier to track treatment areas from one year to the next.
Ridge till also offers farmers an opportunity to test and incorporate such practices as intercropping and deep placement of fertilizer. Placing fertilizer three to five inches below the top of the ridge allows for reduced fertilizer use and fall application, while still providing all the benefits of traditional fertilizer application. -- Lisa Jasa
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|Used properly, this row-crop cultivator can replace all or most herbicides sprayed to reduce weeds. |
Photo courtesy of Northeast Region SARE.
Before the advent of herbicides, row crop farmers cultivated their fields with various mechanical devices to kill yield-reducing weeds. When agrichemical use intensified in the 1950s, farmers abandoned their hoes and tines to take advantage of a solution that promised total weed control with a pass or two of an herbicide-spraying tractor.
Decades later, producers learned chemical weed controls had the potential to degrade streams and rivers or seep into the groundwater. Today, the pendulum has begun to swing back in some regions as crop producers seek viable alternatives to expensive herbicides.
"Farmers are feeling pressure from their neighbors about the amount of spraying they do, and they have economic concerns as well," says Jane Mt. Pleasant, a Cornell University researcher who led a SARE project testing mechanical alternatives to herbicides. "Many farmers think it's better for the land -- they feel stewardship toward their land and think we need to be acting more carefully. Cultivation seems to be one way of doing that."
The project explored ways to eliminate herbicides as well as ways to reduce herbicide use without affecting crop yields. Over five growing seasons, Mt. Pleasant and colleagues Charles Mohler, Robert Burt and graduate student James Frisch tested mechanical weed control strategies on field corn at Cornell research stations and at three New York farms.
Their primary finding: Farmers can completely control weeds using cultivation, although combining cultivation with a small amount of herbicides may be a better way to manage time and maintain yields with the least risk.
The researchers found differences of less than $5 an acre when they compared the production costs of broadcasting herbicides against cultivating. When they focused on net returns from corn yields, which can be affected if untreated or uncultivated weeds crowd out the corn, they found integrating chemical and mechanical weed control posed the least economic risk for growers. Those trying cultivation exclusively could see yield reductions of 5 percent to 10 percent.
Cultivating requires additional passes across the field. Most conventional corn growers currently make only one or two passes for weed control. Switching to mechanical cultivation could require as many as four or five tractor passes, time and expense few farmers can afford. Combining herbicide banding -- which applies chemicals in narrow "bands" over crop rows -- with cultivating often is the best option for most farmers, Mt. Pleasant found.
Organic farmers who use no synthetic chemicals can pass on their additional costs by charging a premium for their corn. Kathie Arnold, who grows 55 acres of corn for organic grain to feed to her dairy herd in Truxton, N.Y., replaced herbicides with cultivation in the 1997 season.
Her reasoning was partly economic; she receives about $19 per hundred weight for organic milk compared to about $11 for conventional. But Arnold also describes her "conservation ethic," harboring concerns about the runoff from her farm, located in the Cheapeake Bay watershed via the Tioughnioga and Susquehanna rivers.
"We'd done some cultivating and banding in the past, but this year, we decided to transition the whole farm to organic production," she says. "The corn looked as good as any we've seen, although I spent a lot of time on a tractor this summer, cultivating."
Arnold took two extra tillage passes before planting to remove any weeds already present in the soil, then cultivated between the corn rows once or twice during the growing season.
For other producers, it may make most sense to reduce herbicide use -- up to 65 percent, Mt. Pleasant says, without a reduction in yields -- by incorporating mechanical cultivation into the crop rotation.
"The audience we want to target are conventional growers who are relying on chemical control and find ways for them to substantially reduce use of herbicides without substantially changing their management, their equipment or their yields," Mt. Pleasant says. The system "requires some change, but it's a much easier sell than asking all farmers to throw out all their herbicide sprayers and rely totally on cultivation."
The project also examined different cultivation tools for corn growers, from rotary hoes to tine weeders to row crop cultivators. While different mechanical tools work best in particular settings, Mt. Pleasant stressed that cultivating devices available today are a far cry from weeders of old.
"These are not the same tools farmers' parents used," she says. "There is a large array of choices and the tools are much improved."
Farmers who want to cultivate exclusively will want to include tine or rotary hoes as well as standard row-crop cultivators. Other farmers might benefit most from cultivators. The type to buy -- rolling versus no-till or S tine -- is site-specific.
Tillage remains a key component in weed control. A farmer wishing to cultivate to control weeds will till, plant, then cultivate. If he or she has minimally tilled the field to help control erosion, it will be harder for some cultivating tools to penetrate the plant residue left on the surface. Standard cultivators are out; instead, farmers need to invest in a high-residue cultivator.
One of Mt. Pleasant's more surprising results came when she experimented with cultivation timing. Conventional wisdom suggests that farmers control weeds at a specific time in the plant's life cycle, but Mt. Pleasant found more flexibility without sacrificing weed control and, ultimately, crop yields. Modern field corn varieties, leafy and vigorous, act as effective competitors for soil nutrients, sunlight and water against weeds.
"If you let the weeds go, they will substantially reduce yields," she says. "But the idea that they have to be controlled in a certain small window is false. It's much wider than we had thought." -- Valerie Berton
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|Lupin, a protein-rich forage and cover crop, helps increase tropical corn silage yields, generating interest from farmers across the South. Photo courtesy of Auburn University.|
In the early 1940s, lupins were grown extensively across the South as a nitrogen-fixing cover crop for cotton. In its heyday, lupins spread across 2.5 million southern acres.
Today, the legume is rarely used by farmers. When chemical fertilizers gained popularity following World War II, lupins lost their niche as a cover crop. The consuming public, too, has turned away from a nutty, nutritious foodstuff similar to lentils.
Don't write off lupins so fast, says USDA Agricultural Research Service (ARS) soil researcher Wayne Reeves, who came across old literature on the legume while searching for alternative crops to incorporate into sustainable cropping systems in the South. In what he touts as a viable alternative to its widely planted cousin -- soybeans -- lupins hold great potential both as an animal forage and as a product for human consumption.
The write-up piqued his interest in further studying lupins in rotation with common commodities like wheat and soybeans, as well as alternatives such as pearl millet and tropical corn. Reeves, with help from collaborators, obtained a SARE grant in 1993 to test the viability, profitability and resource-conserving potential of lupins in combination with other field crops.
Lupins, pearl millet and tropical corn embellish traditional crop rotations by extending the growing season. Lupins can over-winter while tropical corn and pearl millet can be planted in late spring/early summer for a late harvest.
"Lupin provides an option to grow a feed grain in winter," Reeves says. It shares the high protein content of soybeans, but is easier to process. "A farmer can crush lupins on site without having to buy back a processed feed like soybean meal. You just grind it to crack the hard shell, mix with feed, and you have a good high-protein feed source to use on farm."
As a legume, lupins help fix nitrogen, a real plus in the South, which faces more fertility challenges than other regions. Its wet, warm winters cause denitrification, and its sandy soils facilitate nitrogen leaching.
Working with researchers at Auburn University, the University of Florida and USDA-ARS researchers in Georgia and at the National Soil Dynamics Lab in Auburn, Ala., Reeves tested six cropping systems that included lupins, tropical corn and pearl millet. Reeves was most impressed by the lupins' ability to fix nitrogen.
At one location, lupin acted as an efficient "green manure" that resulted in tropical corn silage yields of 20.5 tons an acre. Those results have generated interest from cotton growers in the Florida panhandle, southern Georgia, Alabama, North Carolina and South Carolina. Growers want to take advantage of a cheap, efficient way of adding nitrogen without setting the stage for water contamination problems that can occur with excessive use of purchased fertilizer.
Lupin's potential as an animal feed or forage and for human food was limited in his experiment by plant genetics, Reeves says. The lupin variety the researchers used proved too sensitive to fungal diseases when planted in spring and summer. The optimum variety would mature earlier -- in May -- to allow another crop, such as tropical corn, to follow during the summer growing season.
The researchers plan to follow up the "intense interest" in using lupin as a cover crop by encouraging seed companies to stock and market two varieties that show most promise. They also are producing a lupin video and management guide.
Tropical corn provides an opportunity to follow lupin in late spring, unlike standard field corn, which southern growers plant in April to reduce the potential for insect damage that can occur when the crop is planted too late. Tropical corn, bred in tropical climes, exhibits a tolerance to common southern pests like armyworm, says David Wright, Extension specialist for agronomy at the University of Florida and a cooperator on the SARE project.
Those findings alone could have a significant impact on southern growers, who could work tropical corn into wheat and soybean rotations. Indeed, the total acreage of tropical corn went from about 3,000 acres 10 years ago to close to 100,000 today, partly a "direct result of the work we have done on tropical corn," Wright says.
Not only did tropical corn yields benefit from following lupin, but pearl millet also performed well behind the legume. At one location, millet yields equalled 129 bushels per acre, with lupin supplying about the equivalent of 60 pounds of applied nitrogen. Millet holds perhaps the most potential as a successful forage alternative in the South because of its drought-tolerance.
Pearl millet is a high-protein grain, measuring between 12 and 14 percent compared to corn's 9 to 10 percent. Pearl millet, therefore, makes a nutritious feed grain for livestock, par-ticularly poultry, appealing to producers across the country who have called Georgia Experiment Station researcher Wayne Hanna for information.
Hanna advocates pearl millet for southern rotations because it survives heat and drought stress. He speculates the grain adapted to such conditions because of its likely origin in tropical Africa."
We have to ship grain in from the Corn Belt," Hanna says. "Our idea was to come up with an alternative crop that likes the droughty, acid soils of the South, and pearl millet fits the bill."
Its ability to withstand African-style heat means pearl millet can grow in late summer. It can be planted as late as mid-July, seemingly thriving in hot, dry periods.
"This crop can be planted after you harvest wheat or canola at the end of May and June, when you can't come in with any other grain crop," Hanna says. "It's not sensitive to the day length and has a short maturing season." -- Valerie Berton
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|Workers at the UC-Davis agronomy farm harvest tomatoes by hand to verify yields in the SAFS project. |
Photo by Jack Kelly Clark.
Both supporters and skeptics in California's Sacramento Valley wondered how sustainable agriculture farming systems would fare compared to conventional in the first large-scale, head-to-head competition of its kind in the nation's most productive agricultural state.
A decade later, people are still intrigued by the comprehensive SARE-funded research project, but what farmers really want to know is how they can incorporate some of the profitable, environmentally friendly techniques identified in the UC-Davis study.
"Now we don't ask whether low-input and organic production is viable," says Bruce Rominger, a Yolo County farmer who raises vegetables and field crops and acts as an adviser for the project. "We know it's viable. We're just trying to perfect it."
Information gleaned from the long-term Sustainable Agriculture Farming Systems (SAFS) project--from feeding soil with cover crops to growing more corn with fewer pesticides and synthetic fertilizers--could help producers like Rominger make a transition to alternative production techniques.
While typical agricultural research studies last two to three years, the SAFS project, now celebrating its 10th anniversary, will run for 12 years. The research compares conventional, low-input and organic cropping systems for tomatoes, corn, safflowers and beans based on pest populations, soil health, crop yields and economic viability.
Researchers are encouraged by the economic potential of crops grown with reduced chemical inputs. Low-input corn, grown with half the conventional amount of pesticides and much less synthetic fertilizer, consistently ranked first in both yields and profits.
In a 1997 comparison, price premiums for organic crops pushed their net returns to $292 per acre, just under the top-ranking, two-year conventional rotation's returns of $305 per acre. Aside from profits, researchers worry that long-term conventional production has the potential to increase disease and degrade soil.
Along with researchers ranging from agricultural economists to water scientists, farmers and Extension specialists are involved in every step of the project. "After all, farmers have always been our foremost experimenters," says Steve Temple, the crop production researcher who leads the project.
The project combines rigorous research with real-world management. The rigor can be found in the 56 carefully managed, one-third-acre plots on the university's agronomy farm. As for the realism, all systems are managed to make a profit, using best farmer practices.
Researchers are studying four different production systems, comparing a two-year conventional rotation of processing tomatoes and wheat to four-year rotations of tomatoes, safflower, beans and corn grown using conventional, low-input and organic practices.
Conventional management follows typical farming practices in the Sacramento Valley, using synthetic fertilizers and pesticides. Low-input management includes cover crops and supplemental mineral fertilizers, as well as pesticides, when warranted. Organic rotations are free of synthetic chemicals and meet state organic certification standards.
Researchers have wrestled with problems common in making a transition from conventional to alternative practices.
To find solutions, researchers get creative at an eight-acre area adjacent to the test plots, nicknamed the "playground," where they test new management ideas before incorporating them into the 56 long-term research plots. Some of the ideas--such as mounting a propane flamer on the tractor for weed control or using weed-eating geese to cut the costs of hand-hoeing--are admittedly offbeat. But the brainstorming has provided some serious improvements in the research.
For example, in the cold spring weather, cover crops and composted manure don't always break down early enough in the season to supply crops with nitrogen, reducing yields.
One solution to nitrogen deficiency was to irrigate fast-growing grass and grass/ legume cover crop mixtures in the fall to build nitrogen early enough to help crops in the spring. Another playground idea that bore fruit was using tomato transplants instead of seeding in low-input and organic systems. Transplanting gave cover crops longer to grow and increased yields. Direct-seeded tomatoes should be planted about Feb. 15, while transplants can be planted as late as April 10, allowing time for the cover crop to accumulate more biomass and fix nitrogen.
To help farmers compare the bottom line for each rotation, economists use actual input costs, crop yields and market prices to model returns for hypothetical 2,000-acre farms.
Except for weeds, which accounted for 25 percent of operating costs, significant pest problems did not emerge with alternative management. But the high labor costs for hand hoeing tomatoes considerably raised the costs of growing low-input and organic systems.
Overall, the four-year rotations have shown comparable returns over the years, though each has strengths and weaknesses. Because processing tomatoes are the most profitable crop, a two-year conventional tomato/wheat rotation won out economically, though the production system raised concerns about the potential for increased disease and soil degradation. A conventional four-year rotation has the lowest costs, but not the highest returns. Reduced pesticide use in the alternative rotations lowered input costs and the risk of groundwater contamination. Alternative methods also improve soil structure, along with its ability to take in water and nutrients.
Low-input systems, on the other hand, produce well but have higher costs than conventional. Organic production, the most expensive, also showed the best profits in 1997, if current price premiums were factored in.
Rominger, who uses both conventional and organic methods on his farm, says the project's results can be applied in the real world. It's helped him learn "volumes" about soil science and given him the idea of using transplants with organic tomatoes.
"We can take risks that farmers can't," says Sean Clark, the research manager. "We want to be a proving ground for what works." -- D'Lyn Ford