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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. |
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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
NORTHEAST
REGION
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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. |
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"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
SOUTHERN REGION
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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. |
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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
WESTERN REGION
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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. |
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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
Ten Years
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