Managing 'N' for economics, the environment
ST. CLOUD, Minn. — Would the "best practices" for fertilizer application be enough to prevent water contamination? What restrictions will society impose, and to what effect? Can we afford it and who should pay the bill?
These are some of the questions answered at the fourth annual Nitrogen: Minnesota's Grand Challenge and Compelling Opportunity Conference, Feb. 6 in St Cloud, Minn. About 130 regulators, scientists and ag professionals gathered for the event, hosted by the University of Minnesota Extension Service.
Matt Helmers, an Iowa State University professor of agricultural and biosystems engineering, is on the nitrogen science team involved in the Iowa Nutrient Reduction Strategy. That's part of a Hypoxia Action Plan, generated in 2008 by the Iowa's Hypoxia Task Force, which includes state and federal officials.
Several Mississippi River drainage states including Iowa have a goal of reducing nitrogen in the Mississippi River by 45 percent by the year 2045. Some in agriculture think that's too aggressive. About 20 to 30 percent of the nutrients come from poultry, hogs and cattle in Iowa.
"To reach the goals, farmers may need to use cover crops that provide long-term benefits but not short-term benefits," Helmers said. "They may need to install wetlands, bioreactors or saturated buffers."
ISU works with SERA 46 (Southern Extension Research Association), a multi-state group to educate producers and other stakeholders on what we can do to reduce nitrogen delivery to downstream water bodies, particularly the "hypoxic zone" of the Gulf of Mexico.
There were state efforts to reduce nutrient levels prior to when the SERA 46 group was established, Helmers said.
"Historically we've been concerned about sediment loss and nutrient loss, but there weren't defined goals," Helmers said. More recently they've focused less on nitrogen losses through leaching to groundwater and tile lines.
Some in agriculture are concerned about the costs.
Steve Sodeman of St. James, Minn., a recently retired independent crop consultant and educator, has been a leader in the Minnesota Corn Growers Association's efforts to study the true causes and effects of hypoxia, a fertilizer-fed algae bloom.
Sodeman said "mineralized nitrogen" comes from soil naturally and will always affect water quality, regardless of what agriculture does. Eliminating all crops would reduce water nitrogen to 2 parts per million (ppm) to 10 ppm, compared to 10 ppm to 25 ppm, sometimes seen today. The highest amounts are in the cases where "bad actors" have caused excesses, or in periods of droughts followed by untimely, excessive moisture.
Sodeman says producer checkoffs on fertilizer sales generate about $1 million annually in Minnesota and about $3 million in Illinois to help pay for the burgeoning research efforts.
To compare, Helmers said Iowa officials have estimated it might cost a whopping $750 million a year — three quarters of a billion — to address the problems. Helmers said there might be some offsetting "small business opportunities," including seeding and managing cover crops, land improvement designers and contractors.
Who will pay?
"I think states are struggling on who pays for this, should there be some shared responsibility?" Helmers acknowledged.
Sodeman is among those who point out that hypoxia is focused on saving the Gulf shrimp industry while that faces much larger concerns from capital costs, labor and foreign competition — even inland shrimp production competition like Balaton and Luverne in Minnesota.
The U.S. has been producing more bushels of corn per unit of nitrogen fertilizer, Helmers said. Crop yields have increased, but nitrogen applications have gone down. At the same time, the nitrogen content in a bushel of corn has gone down from 1.3 percent to about 1.1 percent over 30 years.
"We are breeding for bushels of corn per acre — maybe not protein or nitrogen content of the grain," Helmers said.
Fabien Fernandez, a UMN associate professor in the soil, water and climate who helped organize the event, talked about nitrogen timing research. He said farmers can cut the potential for nitrogen leaching into groundwater by minimizing applications in April, May and early June, when 70 percent to 75 percent of the potential for loss occurs. He suggests applying small amounts of nitrogen shortly after planting and then during side-dress application time, particularly in the central sand irrigated regions. There is less nitrogen loss in July and August because the crop is using a lot of the water available to it.
Fernandez and Jerome Lensing, an advanced nutrient management specialist with the Minnesota Agricultural Water Resource Center, are leading a similar conference — the 10th Annual Nutrient Management Conference — to be held Feb. 20 in Mankato, Minn. That conference widens topics to phosphorus and sulfur.