may harm water
warns farmers of the risks of overusing manure
Mike Wowk /
Article courtesy of The Detroit News
November 13, 2001
* The Federal Clean Water Act mandates
that manure and any associated nutrients must not
affect surface waters.
* Michigan guidelines state that
manure should not be applied to soils within 150 feet
of surface waters or to areas subject to flooding
unless the manure is immediately absorbed into the
soils or conservation policies are used to protect
against runoff and erosion.
Livestock farming is more than just
feeding and tending the animals. The following is
an excerpt from a Michigan State University Extension
newsletter on manure management:
"Assume you drive 160 rods across
a field. (160) times 16.6 feet per rod equals 2,656
feet driven. You measure the width of (liquid) manure
application to be about 12 feet. Twelve times 2,656
equals 31,872 square feet. Divided by 43,560 square
feet (one acre) equals 0.73 acre. Assume the (manure)
tank holds 2,800 gallons. Divide by 0.73 of an acre.
(That) calculates out to an application rate of 3,836
gallons per acre."
TOWNSHIP -- Third-generation dairy farmer Tom
Schramm doesn't like chemical fertilizers.
"Manure is better because it's higher
in nutrients," he said.
His 70 dairy cows produce about 30 cubic
yards of manure each day on the Macomb Township farm. He
uses it on alfalfa and other feed crops grown for his cattle.
Schramm's mother, May, said the family
makes sure to keep the manure from leaking into the water
"The public's concern would be if we spread
manure by the river near the farm," said May Schramm, 54.
"We have enough ground that we are able to spread it and
not cause a problem."
The Michigan State University Extension
office in Macomb County is trying to alert farmers of the
potential dangers to humans if manure and fertilizer get
into the water supply. The Extension offers workshops to
farmers, and livestock and horse owners about how to best
manage and dispose of manure.
Environmental advocates, like Doug Martz,
head of the Macomb Water Quality Board, have long argued
that farm animal waste and fertilizer runoff are partly
to blame for the high E. coli bacteria levels in streams
and other tributaries leading to Lake St. Clair. Those high
levels have forced Macomb County health officials to periodically
close beaches along Lake St. Clair and at Stony Creek Metropark.
The bacteria can cause skin irritations
if humans come in contact with it, and other illnesses if
There's a science to knowing how much
manure to spread over how many acres, according to Hannah
Stevens of the MSU Extension office in Clinton Township.
The calculations involve measuring the types and amounts
of nutrients, all the while being careful not to pollute
any nearby lakes or streams.
And the ecological implications of manure
management are becoming more important as the federal government,
through its Environmental Protection Agency, now is starting
to take an interest in the issue, Stevens said.
"So far, there are no federal regulations
on manure disposal, and we'd prefer to keep it that way,"
she said. "We think we can do a better job at the state
level because we're familiar" with local soils, waters and
Michigan livestock owners are encouraged
to comply with the state's Generally Accepted Agricultural
and Management Practices for Manure Management and Utilization.
Farmers and others who follow those guidelines will have
some legal protection in case someone files a nuisance complaint
against them with the state's agriculture department.
Some of the guidelines state:
* All fields should be sampled at least
once every three years, and the soils tested to determine
where manure nutrients could best be utilized.
* Follow fertilizer recommendations to
determine the total nutrient needs for crops to be grown
on each field that could have manure applied.
* Analyze the manure for percentage of
dry matter, and also for ammonium, nitrogen, potassium and
* Manure should be uniformly applied.
Years ago, when most farms were self-contained
economic units, farmers practiced some form of manure management,
Stevens said. "But as the farms have become more specialized,
many of them have lost the ability to handle it."
And then there are the agricultural newcomers,
like former urban dwellers who move to the country and buy
a horse or two.
"These are what I call the hobbyists,"
Stevens said. "Sometimes, the manure produced by the horses
becomes a nuisance to the neighbors."
For most Macomb County farmers and livestock
owners, it's not a question of using manure vs. chemical
fertilizers. The manure is strictly a supplement, and then
only for livestock feed crops, like alfalfa or hay, Stevens
No environmental damage would result if
manure is used properly. "But it can be overused. Also,
there are potential bacteriological pathogens," Stevens
This is where water-quality experts are
"If there is a high-nutrient level in
manure that gets into (a lake or stream), the bacteria in
there will have a feeding frenzy," said Jessica Opfer of
the Clinton River Watershed Council.
"That could lead to increased growth of
plants and algae, and that would have an affect on the fish."
E. coli bacteria is commonly found in
all animal wastes, including that from humans. When that
bacteria finds its way into a waterway, there are potential
health risks to humans as well, Opfer said.
"Manure management is definitely a big
issue (in water quality)," she said. "There's been much
discussion (among environmentalists) about large livestock
operations and how they handle their manure."
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