Natural Resource Protection
NORTH CENTRAL REGION
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|Creative farmers seed a mix of forages around wetlands, allowing for bird nesting in the spring and late-summer grazing for livestock. |
Photo by Diane Rickerl.
Wetlands are an integral part of the agricultural landscape in the Northern Plains. The "prairie potholes" that dot fields across much of this semi-arid region play a big role in recharging groundwater and preventing flooding. They also provide rich habitat for wildlife, particularly migratory waterfowl.
To many farmers, however, wetlands remain a nuisance. It's tough to maneuver large tillage, planting and harvesting equipment around their perimeters. Adjacent cropping areas are slow to dry out in spring, often delaying planting. Venture too close, too early and the soggy soil can mire a big tractor up to its axles in mud.
Fortunately, an interdisciplinary SARE-funded study is showing that what's good for the wetlands and the birds also can be good for a farmer's bottom line.
"Some people think that farm profitability and environmental concerns are always at odds," says Diane Rickerl, an agroecologist at South Dakota State University. "But in this case, they don't compete. They complement each other."
Rickerl headed up a study team that included agronomists, economists, wildlife experts, soil microbiologists and others who exhaustively analyzed the wetlands and farm management on three cooperating farms: a typical conventional farm, a farm in transition to no-till farming practices and an organic farm.
The species richness of waterfowl breeding pairs was greatest in wetlands on the organic farm, researchers found, with 78 bird species present on the organic farm compared to 57 in the conventional system. Wetland plant species also were more diverse.
"All in all, you can see what a wonderful pocket of diversity wetlands are," says Rickerl, who credits South Dakota for retaining about 65 percent of its original wetlands, when other agricultural states in the Midwest have dropped to less than 5 percent.
The nature of the wetlands themselves and the surrounding landscape probably had more effect on wildlife than the farming practices, Rickerl suspects. But the organic farm also benefits wildlife because of the greater diversity of crops that are found in fields adjacent to the wetlands.
Maintaining small fields of different crops in a patchwork pattern on his 1,200 acres preserves diversity for Charlie Johnson, an organic farmer near Madison, S.D., whose operation served as the project's organic test farm. A third of his land is in forages Johnson rotates with small grains, corn and soybeans. In many fields, rye cover crops protect soil that would otherwise be vulnerable to erosion over the snowy winters, and prairie potholes dot the landscape.
The study's economic analyses found that the organic farm is the most profitable of the three systems if the premium prices received by Johnson for his grain and beef are included. If the premiums are ignored, the organic system is the least profitable.
More importantly, it turns out that all three farms were losing money on land cropped within 75 feet of wetlands.
"Attempting to raise crops close to wetlands can be futile," Johnson says. "Rather than investing in a crop there year after year and watching it fail more often than not, a better alternative is to plant permanent vegetation."
Johnson did just that, seeding a forage mix of switchgrass, bromegrass and alfalfa around some of his wetlands. "We leave the spring growth for nesting habitat. Then we graze it or hay it later in summer when our other pastures have dried up," he says. "The wild hay makes excellent feed for our young beef stock."
Not only are those permanent wetland buffers more profitable for Johnson and good for wildlife, but the study team also found them to be effective nutrient filters. Forage vegetation trapped half of the nitrogen and phosphorus that would otherwise have ended up in the wetland, their study found.
"We usually think of wetlands as being the buffer that filters out the nutrients," Rickerl says. "But now we're seeing they're even more efficient if we buffer the buffer with permanent vegetation."
The study team also found that the smaller wetlands ducks prefer are better at filtering nutrients out of water. "That's important because it is the small wetlands that cause so much controversy in the Prairie Pothole Region," Rickerl says, referring to the reluctance of many to leave small pockets of wetland around which they need to drive their heavy equipment.
Where wetlands are farmed through, the soils can become so overloaded with phosphorus that the nutrient can move into groundwater, or flow out of the wetland to contaminate other surface waters, the team speculates. That situation is very unusual for phosphorus, which normally is bound tightly in the soil, Rickerl says.
"What's the effect?" she asks. "No one knows. But the point is that farmers are wasting money by adding phosphorus fertilizer to these areas that their crops can't retrieve."
Wetlands play an important role in storing water and replenishing both soil moisture and groundwater. Forty percent of the water entering wetlands either remained there or moved into the soil or groundwater, researchers found.
Water budgets from the study also showed that 60 percent of the water entering wetlands is runoff from surrounding fields, which has a tremendous potential to be contaminated with nutrients and other ag chemicals.
"That points out the tremendous role wetlands play in the water cycle," Rickerl says. "That's water that we should be using to recharge the soil and groundwater. Without the wetlands we'd be sending it down the river to cause flooding elsewhere."
Rickerl is continuing her efforts with educational programs to help farmers understand that wetlands and profits can go hand-in-hand. "Regardless of the wildlife benefits, our surveys show most farmers still want to drain wetlands," she observes. "We're trying to show that by managing wetlands properly, money and nutrients can stay on the farm."
Johnson already knows that from experience. "Sometimes we forget why the wetlands are there," he says. "With the forage borders, they can be good for wildlife, good for flood control and produce good feed for livestock. You can't ask for much more than that." -- Craig Cramer
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|Waiting until hairy vetch flowers to incorporate it into the soil maximizes the amount of nitrogen the legume will supply for the next crop. |
Photo by Andy Clark.
"Do you think we're hitting 200 bushels?" shouted Norman Brittingham over the din of the combine as he maneuvered through one of the strips we had marked in his corn field.
I was riding shotgun with a map of the fertilizer treatments we were testing in a cover crop research project on his Maryland farm. We were measuring corn yields to find out if Brittingham's use of cover crops as a non-synthetic fertilizer was an adequate substitute.
Brittingham was one of 10 farmers who collaborated with University of Maryland researchers in a SARE-funded project studying cover crops as a tool to reduce nitrogen pollution in the Chesapeake Bay watershed. The bay, an estuary of national significance, had become a cause celebre among politicians, environmentalists and area residents looking to restore the once-productive fishery.
Morris Decker, a University of Maryland researcher, sought a possible remedy for one of the biggest suspected bay pollutants: nitrogen from crop/livestock farms. He was trying to determine whether Bay-area farmers could reduce their fertilizer use -- thereby further lessening their impact on the watershed. My role, as a Ph.D. candidate at the university, was to assist Decker in designing, coordinating and analyzing studies throughout the state.
Brittingham volunteered to test the amount of nitrogen fertilizer we could replace by growing a winter cover crop of hairy vetch just before planting corn. By adding different amounts of fertilizer to the corn, we determined how much of the purchased nitrogen could be replaced by growing the vetch, a legume that "fixes" nitrogen without sacrificing crop yields.
Grass cover crops like rye, wheat and barley take up excess nitrogen in the fall and winter, preventing it from leaching and ending up in the bay. Legume cover crops such as crimson clover, winter peas and hairy vetch "fix" nitrogen by transferring it from air to soil via nodules on their roots.
Mixing grasses and legumes proved a great option. Farmers could realize multiple benefits, including guarding against erosion, preventing nitrogen leaching, adding low-cost nutrients for their crops and providing a water-conserving mulch that helped to increase yields during Maryland's typical hot, dry summers.
"Extensive research and farm demonstrations have shown that a winter cover crop of hairy vetch can fix most -- and sometimes all -- of the nitrogen required for maximum corn yields," Decker says. "The cover crop mulch conserves moisture, increasing yield by helping the corn use the nitrogen more effectively."
Most of the corn strips in Brittingham's irrigated field yielded 150 to 170 bushels per acre, whether we had applied low or high rates of synthetic fertilizer. That meant hairy vetch supplied most of the nitrogen needed by the corn crop. Brittingham could save on his fertilizer bills, and by applying the right amounts, would not send any extra nitrogen to pollute the bay.
Other cooperating grain or crop/livestock farmers in Maryland planted rye, wheat, barley, crimson clover, winter peas, hairy vetch or mixtures of grasses and legumes. Cover crops protect and improve the soil during a time when no other crop normally would be grown, such as during the winter in the Northeast
."A vetch/rye cover crop mixture provides more benefits than either one alone," Decker says. "When residual fall soil nitrogen is high, rye will dominate the mixture, but when soil nitrogen is low, vetch will dominate, fixing more nitrogen. This provides producers an excellent management tool."
We had tested those cover crops in very small plots on university research farms and needed to validate our findings in the field. Cooperators used different rates of nitrogen fertilizer to help us tease out more information about how the cover crops affected nitrogen dynamics on a farm scale. Decker also took the opportunity to demonstrate to farmers the value of using cover crops in their operations.
The farmers helped us confirm it usually was best to wait until late April to kill the cover crops, especially legumes or legume/grass mixtures, in preparation for the cash crop. This allowed the legume to fix more nitrogen, and resulted in more cover crop mulch and better moisture conservation. Many farmers like to plant their corn at about this time, so we hoped to show them that corn yields often were better if they waited the extra week or two to realize the full benefit of the cover crop.
On the bay's western shore in Frederick County, Joe Hottel took the fertilizer test one step further. He dedicated more than 90 acres of his diversified crop/livestock farm to test three- to 10-acre strips of cover crops, different fertilizer rates and applications of sewage sludge.
Cover crops could play a role in managing the nutrients contained in the sludge -- taking up excess nitrogen in the fall and releasing it back the following year for the corn.
"I like what cover crops do for my soil," Hottel says. "They keep the soil from eroding, which I really like when we get heavy rains. This farm was full of erosion gullies when I took it over. They're all gone now."
By season's end, Hottel's yields ranged from 130 to 160 bushels per acre, comparable to his usual take. Moreover, the combination of cover crops and sludge reduced his fertilizer bill by about $30 per acre. He also saved about $20 per acre in tillage costs and $10 per acre in lime costs.
Hottel was on board. Now he puts all of his 1,600 acres in cover crops and uses sludge where he can on his corn-soybean rotation.
"I grow cover crops on as much land as I can every year," he says. "When you have something that works, you don't change. And, if you don't take care of your ground, it's not going to take care of you." -- Andy Clark
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|Researcher Seth Dabney gestures toward a $100 grass hedge that controls erosion: constructing a terrace costs $4,000. |
Photo by Gwen Roland.
Jones Creek whips through John Briscoe's cotton field like a garter snake. During a rainstorm, water moves in sheets down the sloping field toward the bank, taking Briscoe's soil with it.
"Every year, two or three new ditches washed out too deep to cross with a picker," recalls Briscoe, who raises cotton, soybeans, corn and beef cattle on a third-generation family farm in north Mississippi. "One year we had an absolute gulley washer that left a hole big enough to put a house in. We had to use a 'dozer to fill it in and put a levee around it."
In 1995, he had only two choices to comply with Mississippi's erosion control rules: He could build terraces or convert to no-till farming. He opted to build a terrace. While it did slow the wash of topsoil from below the terrace, a year later ditches began forming above the structure.
This time Briscoe had a third choice for conservation compliance: He could plant an inexpensive vegetative barrier above the terrace to slow water flow and trap sediment.
In part thanks to SARE research headed by Seth Dabney, vegetative barriers -- or grass hedges -- have been added to the Natural Resources Conservation Service Field Office Technical Guide for Mississippi as an approved erosion control practice. Grass hedges also are eligible for cost share through the Environmental Quality Incentives Program (EQIP).
An NRCS district conservationist recommended that Briscoe talk to Dabney about trying a hedge in his field. The researcher and the farmer walked the field together and reviewed the options.
Though he was skeptical about the effectiveness of a hedge, Briscoe opted to plant one rather than use more precious topsoil to build another terrace. It was a purely financial decision. At $6 a pound for switchgrass seed, Briscoe could sow a 10-foot hedge across his field for about $100. The terrace would have cost about $2 per foot, or $4,000 to cross the 50-acre field.
After evaluating the hedge for two seasons, Briscoe is convinced he made the right choice. A 10-foot swath of blue-green switchgrass waves across the sloping cotton field like a Mohawk haircut. At ground level, the space between thousands of reed-like stems is clogged with soil trapped on its way to the creek. But most telling of all, no new gashes are splitting the hillside.
"Not only is it working, but it takes up less space than terracing," says Briscoe, sweeping his arm over rows of cotton blossoms jostling against the hedge. At 50 feet wide, the terrace takes up about two and a half acres of his field. At only 10 feet wide, the hedge takes up about one-fifth that space.
Mowing once or twice a season is the only maintenance required once the hedge is well established, says Dabney, who has been researching vegetative barriers for nearly a decade. "During the first season there may be washouts in the hedge at the points of highest water flow," he says.
Such washouts can be fixed in a few minutes with a shovel. A terrace, on the other hand, needs regular maintenance often requiring earth-moving equipment.
Although many plants may make up a hedge, the ideal hedge grassplant is cold hardy with thick, woody stems and dense, erect growth. Dabney's research shows that Alamo switchgrass has those characteristics, so that's what is specified in the Mississippi standards. Switchgrass also has the advantage of being a native plant that doesn't invade the cash crop.
"It's not invasive because it is kind of a slow starter," says Dabney. "Crabgrass and other annuals can choke it out if given a chance, but John established an effective barrier the first season. By the second season, it is solidly established."
Farmers should not assume vegetative barriers can replace terraces in all situations, Dabney cautions, since there are areas of concentrated water flow where vegetation couldn't withstand the force. "Hedges can slow down runoff waters and trap sediment," he says. "They may even enhance infiltration, but they will not completely intercept and cut off runoff waters. As field sizes increase, hedges reach a limit where other technology is needed to handle the accumulated runoff."
The official acceptance of vegetative barriers doesn't mean the research is over. Far from it, says Dabney. Among other things the research team is looking into the pest management characteristics of the hedges. An Arkansas researcher determined hedges attract big-eyed bugs and other beneficial insects.
"It may turn out that there are enough benefits to work hedges into an IPM program," Dabney says.
The search for better varieties of switchgrass continues. Project cooperator Joel Douglas of the Jamie Whitten NRCS Plant Materials Center has been breeding switchgrass from wild collections since 1993. He hopes to develop a shorter switchgrass that would require less mowing, saving farmers time and money.
Douglas' research plots have reduced a slope at the Whitten Center from 7-percent grade to 5-percent grade in just four growing seasons. "All we did was plant them and leave them alone," he says. "In addition to the soil buildup and leveling, we also have improved filtration when it rains."
Even though vegetative barriers have been used for thousands of years in other countries, Mississippi is the first U.S. jurisdiction to officially recognize their effectiveness. The inclusion of vegetative barriers in Mississippi's interim standards also marks the first time a SARE project has directly influenced state agricultural policy.
Dabney, who is based at the ARS National Sedimentation Lab at Oxford, is now working with a committee revising the National Interim Practice Standard for grass hedges.
As for Briscoe, seeing how the hedges hold soil in place is encouraging him to consider additional changes on the family farm.
"In my lifetime I've seen ditches get bigger. That may be the result of so much timber being cut in the area -- or it could be from our farming practices."
Briscoe, whose neighbor no-tills 2,500 acres of cotton, now is considering incorporating the practice. "The savings in just labor is enough to make you take it seriously," he says. -- Gwen Roland
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|Geese return to Tulelake National Wildlife Refuge's rejuvinated wetlands next to farms that provide a vital waterfowl food source. |
Photo by Carol Shennan.
In a 39,000-acre national wildlife refuge that borders the California-Oregon state line, agricultural and wildlife habitat protection interests have maintained an uneasy relationship since the 1960s.
In 1964, the Kuchel Act set up the Tulelake National Wildlife Refuge to help preserve one of the nation's premier nesting sites for waterfowl, with a twist: It mandated that "optimum consideration" be given to agricultural enterprises in the area. Since then, farmers have leased land in the refuge to grow potatoes, small grains, alfalfa, onions and sugar beets.
The farmers are following in the footsteps of their parents and grandparents, who migrated to the fertile valley in and around the present-day refuge in the late 1800s. But their farms bordering and within the Tulelake Refuge, while yielding about three times more per acre than in less fertile areas, are part of a stop on the Pacific flyway that attracts 1 million waterfowl each year.
While such competing interests usually come to a head, a compromise of sorts has worked in the Tulelake Refuge since the Kuchel Act. That act recognizes the incredible soil fertility and importance of agriculture to the local economy as well as the vital source of food farming provides to the waterfowl. The complementary relationship worked for years until scientists discovered the wetlands were declining.
As opposing forces debate the future of the Tulelake Refuge, a group of researchers, refuge staff and farmers have devised a system to rejuvenate the wetlands while perpetuating agriculture. A key player in that work, SARE-funded researcher Carol Shennan, has helped set up a system that rotates wetlands and farming to rejuvenate the marsh and offer prime soil to participating farmers.
"The wetlands are no longer good habitat for birds," says Shennan, an agroecologist at the University of California-Santa Cruz. Studies have shown agricultural runoff is a not a major factor in that decline. Most of the refuge, governed by an old flood control plan that ended the alternating ebb and flow of water that occurs in a natural wetlands system, is stagnant.
"We have a very mature unproductive marsh where few new plants germinate because of stabilized water depths, and there is little habitat diversity," Shennan says. "Under rotational management, we can use agriculture as a disturbance to break the cycle and restore young stages of marsh development."
The project creates rotational land uses -- wetlands or farms -- that switch every three years. Farmland is flooded to create wetlands of differing water levels, while unproductive wetlands are drained to create farmland on soil untouched by a plow for decades, at least. The system promises more diverse wetlands and fertile farm soil that needs few, if any, amendments.
The complicated system already has brought results. In just the second year, a former farm in active production for 40 years sprouted diverse flora, with tules, bullrushes and cattails growing just months after flooding.
"It's been really astounding," says Dave Mauser, a wildlife biologist at the refuge. "In little marshes we've created, we're getting wetland vegetation the first year out of farming. It's a quick transition, and the bird use has really followed suit."
For farmers who lease land in the refuge, the project offers an unparalleled opportunity to reduce their use of purchased fertilizers and pesticides. The virgin soil hosts few, if any, soil-borne pathogens like nematodes.
Sid Staunton, who grows potatoes, small grains and onions on 1,500 acres both adjacent to and on refuge-leased land, hopes to secure a lease on the converted wetlands. He anticipates a big savings in input costs such as nematacides, which can run $250 an acre.
"We'd have a disease-free soil that's really rich in nutrients, so we wouldn't need to put in huge inputs," says Staunton, who serves on Shennan's 10-member farm advisory committee. "It's a good way to use a natural system to clean up some of the soil-borne problems that build up over time."
Rotating the two land uses for the mutual benefit of farming and wildlife habitat perfectly meets the intent of the Kuchel Act, Mauser says. The legislation creating the farm lease program provided surplus ag crops for birds while keeping them from the high-value rice crop in California's Central Valley.
Farmers leasing refuge land are used to bird pilfering, Staunton says. Most of that occurs on grain stubble because the birds migrate in fall after harvest or in spring before planting.
Shennan also is working with farmers to increase their use of cover crops to provide habitat for nesting birds, reduce soil loss through wind erosion, suppress weeds and improve soil organic matter. It's especially challenging in the basin because of a 4,200-feet elevation that can bring severe frosts year round.
The project also establishes the long-term transition of farmland into what Shennan hopes will become a productive, mature marsh. Using computer modeling, she will study different rotation scenarios on a refuge-wide scale.
"We want to set up a framework to judge impacts of each potential rotation design on water quality, habitat diversity and economics," she says. "It involves looking at the system from multiple perspectives so we can use it as a tool with farmers, environmental groups, hunting groups and refuge managers to quantify benefits and tradeoffs. There's a tremendous amount at stake."
Some farmers remain skeptical about the future of farming in the Tulelake Refuge. Staunton, on the other hand, is optimistic the new system will lower costs for farmers while improving wetland and wildlife values.
"It's a real on-the-ground solution, and, for the amount of money invested, the dividends are incredible," he says. "This thing could solve this area's resource conflicts quickly, and we can continue to have good food value from this area." -- Valerie Berton