NEWS for North Dakotans
Agriculture Communication, North Dakota State
University
7 Morrill Hall, Fargo, ND 58105-5665
June 25, 1998
For years North Dakotans have used trees and other vegetation to protect the land. Now research is showing farmers and others how to use those plants to protect water.
Although buffer strips have been used for many years in the Corn Belt and eastern United States, they are now becoming more widely used throughout the rest of the country. More and more farmers and land managers are using strips of trees, bushes, grass and other vegetation to keep pesticides, nutrients and sediments out of water resources, notes Bruce Seelig, a water quality expert with the North Dakota State University Extension Service.
In buffer strips, areas of different types of vegetation may be planted specifically for water quality protection. These strips are located on the landscape to intercept the flow of surface water. Their purpose is to remove unwanted material from surface water before it enters a channel, stream or lake.
"Our problems with that kind of nonpoint source pollution aren't as severe in North Dakota," Seelig says. "But buffer strips can be still be a very effective tool for us to use in protecting water in this region as well."
He notes that some new alternative crops and evolving farming practices may make nonpoint source pollution a growing concern in North Dakota.
Seelig says that as producers and other conservationists learn more about how agricultural contaminants such as nitrogen and pesticides move from cropped fields into water resources, they're showing more interest in establishing filter strips for water quality protection.
Generally filter strips that alternate with cropped strips or that occur on the edges of cropped fields are composed of grasses and are most effective in removing sediment and adsorbed chemicals such as phosphorus. However, these types of strips are not as effective in removing soluble contaminants from water such as nitrate or certain pesticides, Seelig says.
And the strips must be located and maintained correctly. If water moves too rapidly through the strips or if they become clogged with sediment, their effectiveness is limited.
Buffer strips that run parallel to streams or lakeshores, called riparian buffer strips, generally consist of different vegetative zones, ranging from grasses to mature trees. Recent studies show that in addition to filtering out sediment, riparian buffers can degrade, adsorb, and transform nutrients and pesticides as they are carried from fields by water.
"The standards for width, vegetative composition, management and maintenance of vegetative filter strips vary by the intended purpose," Seelig explains. "A simple grass filter strip separating cropped fields on the contour is drastically different in function compared to a strip that runs adjacent to a stream."
Generally filter strips established in upland areas are composed of cool season grasses and are widest on steeper fields. Riparian buffer strips adjacent to streams have widths greater than field buffer strips and may be several hundred feet wide. These buffer strips often have an undisturbed forest zone nearest the stream next to a managed forest zone that is adjacent to a grass zone farthest away from the stream. The grassed zone removes sediments while the forested zones remove nutrients and other chemicals such as pesticides.
"The effectiveness of vegetative filter strips under many conditions is still relatively unknown and is dependent on local factors such as soils, climate and hydrology," Seelig notes. "However, it's generally accepted that the benefits of filter strips can be significant, especially if combined with other conservation practices."
An ongoing riparian buffer strip project in eastern North Dakota was recently expanded to demonstrate and explore how buffer strips can best work under North Dakota conditions. For more information, contact the project coordinator, Linda Kingery at the Red River Resource Conservation and Development Office, Grafton, N.D., phone (701) 352-0127.
Additionally, the Natural Resources Conservation Service (NRCS) has set a national goal to establish 2 million miles of conservation buffer strips by the year 2002. A North Dakota/Minnesota conservation buffer conference is scheduled for July 14-15 at the Doublewood Inn in Fargo, N.D. For further information contact Arlene Deutscher, NRCS (North Dakota) at (701) 250-4768 or Sylvia Rainford, NRCS (Minnesota) at (612) 602-7914.
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Source: Bruce Seelig (701) 231-8690
Editor: Tom Jirik (701) 231-9629
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