Requiring farmers to plant grass buffers between crops and streams would help clean Iowa’s water while minimally affecting farmers and crop acres, according to a report from the Environmental Working Group.
“We were trying to look for simple conservation practices that could make a big difference, and buffer strips appear to be the most cost effective,” said report co-author Craig Cox, the organization’s senior vice president of agriculture and natural resources.
The report’s title refers to mandatory buffers as “Iowa’s low-hanging fruit,” he said.
The report found that buffers between cropland and waterways could achieve two-thirds of the 29 percent reduction in phosphorus pollution from non-point, mostly agricultural sources specified as a goal under Iowa’s Nutrient Reduction Strategy.
Using high-resolution aerial photography and geographic information systems, Cox and co-author Soren Rundquist, the organization’s landscape and remote sensing analyst, identified streams and the extent to which they were protected by buffers.
With detailed data from Allamakee, Hamilton, Linn, Plymouth, and Union counties, representatives of the state’s five major land forms, they were able to extrapolate the impact of imposing a statewide buffer requirement. They determined that meeting a 35-foot requirement would affect only 8 percent of landowners and that of those affected, 85 percent would need to convert an acre or less of cropland.
A 50-foot buffer requirement would affect 11 percent of landowners in the five counties, and 71 percent of them could meet that standard by converting a single acre or less.
ARTICLE CONTINUES BELOW ADVERTISEMENT
Implementing a 75-foot standard would affect 13 percent of landowners, with 54 percent able to comply by converting a single acre or less, they found
Across the five counties analyzed, 565 acres of cropland would be required to establish 35-foot buffers on all perennial streams; 3,500 acres would be required to establish 75-foot buffers, the authors said.
In Linn County, 72 acres of cropland would need to be converted to attain the 35-foot standard and 455 acres would be needed for the 75-foot standard, they said.
Iowa ranks first in the nation in grass filter strip acreage under the Continuous Signup Conservation Reserve Program, which pays farmers to take land out of production. Of 865,000 acres enrolled in the program nationwide, 200,000 of those acres are in Iowa.
Minnesota, the only state with mandatory buffer strips, ranks second with 127,000 acres.
Iowa, with 56,000 acres of grass and wooded filter strips, ranks fifth in the nation in that category.
Phosphorus pollution from fertilizer and manure that runs off farmers’ fields and into nearby streams can damage human health and aquatic life and is a primary cause of Iowa’s chronically poor water quality.
“Overloading waterways with phosphorus sets off the kind of toxic algal blooms that left half a million people without drinking water in Toledo last summer,” Rundquist said “Algal blooms also keep Iowans from enjoying the outdoors, especially in summer when polluted water often makes fishing, swimming or paddling unpleasant.”
Streamside grass strips are effective at keeping phosphorus out of waterways. Though most nitrate pollution is discharged from subsurface drainage tile, buffers also help somewhat in reducing the nitrate pollution that threatens drinking water supplies.
ARTICLE CONTINUES BELOW ADVERTISEMENT
“Enacting a buffer standard is a simple, effective and easily verified way to get to cleaner water faster than what Iowa is currently doing,” Cox said.
Iowans have been waiting too long to get results from the solely voluntary approach promoted by farm organizations and state officials, he said.
“I think most landowners would agree that planting crops right up to stream banks is just wrong,” Rundquist said. “A streamside buffer standard would protect the good work many landowners are already doing.”