Continuing Education and
Communication Services
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
11/27/01
FOR IMMEDIATE RELEASE
Contacts:
Mahdi Al-Kaisi, Department of Agronomy, (515) 294-1923, malkaisi@iastate.edu
Steve Barnhart, Department of Agronomy, (515) 294-1923, sbarnhar@iastate.edu
Jim Russell, Department of Animal Science, (515) 294-4631, jrussell@iastate.edu
Mark Hanna, Department of Ag and Biosystems Engineering, (515) 294-0468,
hmhanna@iastate.edu
Del Marks, Continuing Education and Communication Services, (515) 294-9807,
delmarks@iastate.edu
Winter Grazing? ISU Says Prevent Pasture Erosion
AMES, Iowa -- A group of Iowa State University Extension specialists and research scientists are cautioning producers who use winter grazing about the potential for soil erosion from pastures, especially on slopes with gradients of 3 percent or more.
ISU Extension agronomist Mahdi Al-Kaisi says that grazing livestock on frozen soil usually translates into minimal damage. "But having livestock on wet or muddy soil can lead to soil compaction, erosion and long-term damage to pasture sod. If the choice is to go to winter pasture, producers should take advantage of the management practices that limit soil erosion."
Steve Barnhart, also an ISU Extension agronomist, says that Iowa pastures have normally stopped growing by November. "The best overall erosion management for pasture is a good sod cover. Close grazing and high traffic generally lead to weakened plants and thinner sod cover. That means that producers have to plan and manage both for forage for winter grazing and for vegetative cover to protect the soil."
The scientists suggest that producers shelter and, if necessary, offer supplemental feed to livestock in areas away from open bodies of water. Giving livestock direct access to open water can lead to stream bank degradation, siltation, poor overall water quality and nutrient pollution and eutrophication. It gets worse when factoring in livestock exposure to bacteria, blue-green algal toxins, foot rot, leg injuries and stress and the problems of calving in mud and streams.
They also recommend fencing livestock away from waterways and ponds and providing clean water. Stockpiled forage (forage allowed to grow and accumulate for use at a later time) is another way to extend the grazing season and maintain good vegetative cover.
ISU animal scientist Jim Russell adds that another management practice recommended for fall grazing is to identify an area and fence it off as a "sacrifice" grazing area for use when conditions are muddy. "Sacrifice areas should be on a relatively level site, be suitable for reseeding and be accessible to supplemental feeding and water, if necessary."
Agricultural engineer Mark Hanna agrees. "To further minimize sod damage, bales can be stored in the pasture behind moveable electric fence to limit tractor traffic. Winter pasture erosion can be a problem, but it is manageable if producers take the right steps."
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