AUBURN, Ill. — A system in the experimental stage has the
potential of not only helping farmers achieve higher yields through drainage
control, but of reducing fertilizer runoff.
So-called “saturated buffers” hold the promise of removing
nitrates from fields by regulating drainage volume. A small test being operated
on the property of Springfield Plastics here is providing valuable information
that will be added to a main research project started three years ago in
Saturated buffers are comprised of drainage tiles that run
underneath buffer strips adjacent to crop fields. The control structure includes
boards that can be raised to allow water to flow or dropped down to stop the
The research in Ames, Iowa, has been promising, Springfield
Plastics President Steve Baker said.
“The first year, they diverted 59 percent of the water that
came down this line and went out into this buffer strip,” he said. “The second
year it was 55 percent. The third year was 32 percent. What’s going on in Iowa
is every time the testing is done we reduce the amount of nitrogen as we get
farther away from this lateral line. After three years we have removed 90
percent of the nitrogen in the amount of water that was diverted.”
The Iowa project, as well as the one in Auburn, is part of
research sponsored by the Agricultural Drainage Coalition, a group of pipe
companies such as Springfield Plastics.
The effort is being done pro-actively, Baker said, to
address pressure from federal agencies dealing with conservation. It is being
partially funded through the U.S. Department of Agriculture.
“We decided we need to promote an environmental method to
control water-managed drainage on farms,” he said. “We know where the pressure
is coming from. Nutrient reduction is a main focus of the Ag Drainage Coalition.
USDA is heavily involved in this thing.”
Two other drainage practices promoted by the coalition have
received official blessing from the Natural Resources Conservation Service. They
are bioreactors and drainage water management.
The site here includes a buffer put in about a half-century
ago for sediment control. The company installed a drainage system 10 to 12 years
ago that altered the water flow.
“We shoved all that water right underneath this buffer, and
all of a sudden, the buffer lost some of its efficiency,” Baker said. “It didn’t
get the amount of water it was getting before. We wondered how we could make it
better, and the concept of a saturated buffer was born.”
Workers installed a control structure accessed through an
above-ground box. The boards under the structure regulate water flow.
They then installed a 4-inch lateral distribution line.
Gravitational pull takes it to a nearby stream.
“Our goal is whatever nitrogen was in that box there, by the
time we got it out there to that stream, we removed the nitrogen,” Baker said.
“We do not want the nitrogen here; this is the Lake Springfield watershed.
They’ve had a couple of spikes on nitrogen, and were really panicky.”
In addition to the main research project in Iowa, the
coalition has installed 15 similar structures, five in Illinois.
“We’ve got water-quality data going on in those. The same
trend we are seeing in Ames, Iowa, we are seeing in Illinois,” Baker said. “The
closer you get to the stream, the levels of nitrogen get less and less.
“From a performance standpoint, we’re a baby right now. We
haven’t walked, because we have only one site in Iowa. Can we duplicate it in
Auburn, Ill.? I can’t tell you that. But what we have seen in the water-quality
tests is that the same level of reduction seems to be occurring. We’re going to
know more in six to eight months.”
He acknowledged that a number of factors can affect the
study, including the different environments.
“Is the vegetation different in Auburn, Ill., than in
Minneapolis, Minn.? Yes it is,” he said. “Will it work better? Based on the
trends we see, they all seem to want to remove this nitrogen. That’s very
positive news; that’s exactly what we want. How we ultimately engineer these
things is yet to be determined. But we had to start somewhere.”
Illinois State Conservationist Ivan Dozier pointed out that
financial assistance is available for tried-and-true drainage systems. If this
one proves effective, there could be cost-share funds for producers who put it
in their fields.
“If you’re using the public’s money they need to do what
they’re supposed to do,” Dozier said. “This being a relatively new idea, we are
supporting it with conservation innovation grants. If something looks like it
has some promise, this is a good step for us to evaluate. There are a whole lot
of different things we’re looking at.”