SLEEPY EYE - A New Ulm crop consultant and a University of Minnesota educator discussed water-related issue with a group mostly made up of farmers Thursday at the Sleepy Eye Community Center.
"There are things that will happen if you don't step forward and ensure they don't," said Steve Commerford of New Ulm. "Perceptions and reality are not always the same." He said the five largest agriculture issues with water are fecal coliform, phosphorus, total suspended solids and nitrates and nitrogen.
Commerford said fecal coliform or E. coli is naturally occurring and that bacteria from field manure don't last more than a few days after it is applied to farm fields, which contrasts with some common beliefs.
"The Federal Clean Water Act was reasonably successful in cleaning up U.S. waters but nutrient removal and storm water management remain a challenge for most cities," Commerford said. He explained that what many people don't realize is that nitrates inhibit (prevent) methyl mercury and blue-green algae growth, which is especially toxic to pets.
Commerford said it wasn't really appropriate to apply drinking water standards to trout streams or even drainage ditches, some of which in Brown County have produced trout fish.
"Don't be afraid to use science to expose issues," Commerford said. "Seventy-five to 80 percent of nitrogen comes from natural sources, not fertilizer or manure. I have serious problems with township well testing used to trigger new nitrogen fertilizer plans. Domestic wells have many causes of high nitrates that are unrelated to nitrogen fertilizer. There is no correlations between nitrogen fertilizer and drinking water wells. BMPs (Best Management Practices don't make any difference. They're simply designed to trigger regulations."
Dr. Satish Gupta of the University of Minnesota, Twin Cities said most phosphorus comes from sewage treatment plants, many of which very heavily polluted rivers years ago, not somebody's backyard or from farms. He said the Minnesota River has sediment up to 65 feet deep.
"Historical records in 1835 describe the Blue Earth River at Mankato as muddy and the major cause of Minnesota River turbidity," Gupta said. "That observation was similar to U.S. Geological Society findings in 1994. Before the 1930s, Minnesota rivers were conduits for city waste, domestic sewer and industrial pollution. People believed rivers could rejuvenate themselves. In the late 1880s, Minneapolis and St. Paul each dumped 500 tons of garbage into the Mississippi River daily. In 1930, the South St. Paul stockyards dumped garbage near the Mississippi River daily, before it was carried away when the river got high."
Gupta said the total phosphorus concentrations in Lake Pepin sediment appears to be from domestic and industrial phosphorus pollution in rivers that was absorbed in riverbank sediment.
"There's not enough money to control river bank sediment erosion," Gupta said. "Tile lines dilute the water. They don't have a lot of phosphorus like some people want you to think. It's a dilemma. What you can do is not apply manure near rivers.
A farmer said conservation tillage hasn't really solved problems.
"We've come a long ways. There are advantages to no-till, on land where it works," Gupta said.
(Fritz Busch can be e-mailed at firstname.lastname@example.org).