A report from the National Research Council (NRC), prepared at the request of the U.S. Environmental Protection Agency (EPA), recommends new measures to help keep nitrogen and phosphorus from reaching the Gulf of Mexico via the Mississippi River.
High levels of nutrients promote the growth of algae and zooplankton. When they die, fall to the bottom and decompose, oxygen in the water is depleted, creating the condition called hypoxia. Marine creatures migrate out of the oxygen-deprived area. This year's hypoxic zone was the second largest on record.
"There is no question that nutrient loadings in the Mississippi River basin are causing water quality problems and Gulf hypoxia,” the report states. Its authors suggest EPA and the U.S. Department of Agriculture establish a Nutrient Implementation Control Initiative, to implement nutrient-control pilot projects in priority watersheds in the Mississippi River Basin.
Among other goals, the pilot projects would evaluate nutrient-control practices and document their water-quality benefits. Knowledge gained from the initiative would then be applied on a broader scale.
Roger Wolf, director of environmental programs for the Iowa Soybean Association (ISA) and a member of the NRC committee that prepared the report, and Dean Lemke, chief of the Water Resources Bureau of the Iowa Department of Agriculture, think targeting is a valid approach. In fact, they say it already is being used in parts of Iowa.
"With water quality issues, we must work at the hydrologic scale, rather than one-on-one, as conservation programs have tended to do in the past,” says Wolf. ISA has launched 13 watershed-scale projects similar to those proposed in the report, he adds.
"There are practices we can use to meet society's nutrient-reduction goals,” says Lemke. "Iowa already has a Conservation Reserve Enhancement Program in effect, developed to address Gulf hypoxia. We have reduced nitrogen loadings of cropland areas of 500 to 4,000 acres by 40% to 90%, through targeting the placement and design of wetlands. I think there are opportunities here for farmers to demonstrate their stewardship, using a voluntary, incentive-driven approach.”
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