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St. Paul, Minn. – As
winter gives way to spring, rapid snow melt and the potential for flooding pose
challenges for farmers who spread livestock manure on cropland. Farmers who
spread solid manure during winter must ensure that it doesn’t run off the
field, with snowmelt flowing to ditches, streams and other waters.
According to the Minnesota Pollution Control Agency (MPCA), manure-contaminated runoff
not only threatens water quality, it reduces the value of manure as a crop
nutrient. If
possible, farmers should refrain from spreading manure during periods of rapid
melt. Minnesota
rules to protect water quality require a 300-foot setback from surface waters
and open tile intakes for all manure spread onto frozen or snow-covered soil.
If
temporary stockpiling is not possible and manure land application can’t wait, to
help reduce the impact of manure applied to the surface of wet, frozen or snow
covered soil, choose the flattest field or flattest parts of fields and follow
these guidelines:
- Field slope should be less than 6 percent
for solid manure, and 2 percent for liquid manure,
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Do
not apply non-incorporated manure within 300 feet of surface waters. If
possible apply manure at even greater setback distances.
- Do not apply in portions of fields that
contain other areas of concentrated flow. A 300-foot setback is required for
intermittent streams; however most fields also contain other areas such as
grass waterways that receive concentrated flow. Keep back as far as possible
from these other areas of concentrated flow.
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Choose fields that contain the most crop
residue; greater than 30 percent is recommended.
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Avoid fields where the furrows are full of
ice and snow.
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Keep application rates low enough to avoid
runoff or ponding during application.
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Choose fields that do not have adjacent
non-tillable land containing areas of concentrated flow such as ravines, ditches
with open side inlets, streams or dry runs. If this not possible, stay as far
away as possible, from these off-field areas of concentrated flow.
When applying manure on snow-covered or frozen soils, producers
should avoid high-risk periods of runoff. These include times when there are two
or more inches of snow on the ground and maximum temperatures are forecast to
exceed 40 degrees within 24 hours, or when there is a prediction of ¼” or more
of rain within 24 hours.
“Producers should consider short-term stockpiling of manure in the
field until after the major snowmelt of the year,” says Wayne Cords, a supervisor with the MPCA's feedlot program. “While this does involve
additional time and labor, there are significant benefits in the reduced pollution
potential, as one well-placed short-term stockpile poses significantly less
pollution hazard than a whole field of surface-applied manure.”
“Producers who are considering surface-applying manure to snow-covered
or frozen soils should work with a crop consultant and complete a Minnesota
Phosphorus Index model to determine the phosphorus loss risk, and then choose
fields with the lowest risk value to winter-apply,” Cords says. “And
NPDES-permitted sites need to carefully read their permit as they have additional
requirements and restrictions when applying manure to frozen or snow covered
soils.”
Livestock farms that experience manure
runoff into waters of the state must report to the Minnesota Duty Officer by
calling 800-422-0798, and take immediate action to reduce environmental impact,
such as creating temporary berms to stop discharge, temporarily plugging
culverts and drain tile intakes to prevent manure inflow, and soaking up liquid
with absorbent material, such as hay, straw, cornstalks or wood shavings.
For more information, see the MPCA
fact sheet, “Managing manure and land application during adverse weather
conditions” at www.pca.state.mn.us/publications/wq-f8-46.pdf,
contact your county or MPCA feedlot staff (see www.pca.state.mn.us/zihy6a1), or
call the MPCA at 800-657-3864.
Broadcast version
Snow melt and flooding
pose manure management challenges for Minnesota livestock farms. Farmers
who spread solid manure during winter must ensure that it doesn’t run off into
ditches, streams, and other waters when snow melts in the spring.
Manure-contaminated runoff threatens water quality and reduces the value of
manure as a crop nutrient. If possible, farmers should refrain from spreading manure during rapid
melting periods. Minnesota rules require a 300-foot setback
from surface waters and open tile intakes for all manure spread onto frozen or
snow-covered soil.
More information is available by visiting the MPCA website and searching for ‘feedlots.’
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The mission of the MPCA is to protect and improve the environment and enhance human health.
St. Paul • Brainerd • Detroit Lakes • Duluth • Mankato • Marshall • Rochester • Willmar
www.pca.state.mn.us • Toll-free and TDD 800-657-3864
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