The Iowa Environmental Protection Commission (EPC) voted at its September meeting to move forward in seeking a ban on application of manure on farmland that is to be planted to soybeans. The EPC asked the Iowa Department of Natural Resources (DNR) staff to write and bring a proposed rule to the EPC's November meeting.
The only exception to the ban would be excessive rainfall that prevents farmers from planting corn by June 1.
Many of the nine-member commission believe soybean plants can adequately fix the needed nitrogen from the air, since soybeans are a legume plant. They believe that banning manure application to soybean fields will reduce nitrates in streams and lakes. The EPC in May directed DNR to work on the rule. Since then, several farmers petitioned EPC to make more subtle changes to the rules regarding the state's manure-management plans, and the DNR staff came back to the EPC to clarify the issue.
Farmers say ban is not necessary
EPC members then voted on Sept. 19 to have DNR write up the proposed rule but to make several changes--including one that would allow the application of manure to land planted to soybeans after June 1. "That would allow farmers to plant beans if wet weather delayed planting their corn in the spring," explained Francis Thicke, a dairy farmer and EPC member from Fairfield.
During the public comment portion of EPC's September meeting, several farmers spoke against the proposed ban. "We finish hogs mainly in hoop buildings," said Dave Struthers of Collins, Iowa. "The nitrogen levels in manure coming from the farrowing and gestation buildings is very low, compared to finishing buildings. That's due to the more limited diet farmers feed to sows and to the use of power washers to clean farrowing facilities often, thus watering down manure in the pit."
"We still need liquid swine manure for fields," says Struthers. "We get more phosphorus and potassium per gallon from our sow manure, which is something our beans need. We avoid applying swine manure on soybeans, but do it only if it is needed." Because of those factors as well as the existence of other nutrients in manure, Struthers says a complete ban is not necessary and would put an unnecessary restriction on farmers.
Why not lower N removal standard?
EPC denied a petition in June by several pork producers to set a lower nitrogen removal rate standard. The pork producers wanted it set at 3.1 to 3.4 pounds per bushel rather than the current factor of 3.8 for manure application to soybeans.
Des Moines attorney Eldon McAfee also spoke on behalf of several petitioners who suggested lowering the standard for nitrogen levels that could be applied to soybeans, rather than banning manure application to soybean acres altogether. McAfee said, "There is no research that shows, when properly applied, there is environmental harm."
EPC member Jerry Peckumn, a Greene County farmer, disagreed. "I see a lot of research that manure is an environmental concern," he said. EPC member Francis Thicke also spoke in favor of a ban. "Allowing liquid swine manure on both corn and soybeans will lead to a build-up of phosphorus in the soil. There's a benefit to the farmer to slow the build up of P."
Other EPC members are reluctant
Other commissioners were reluctant to move forward with a ban. "I'm still not convinced that we have a scientific basis to do this," said Mary Gail Scott of Cedar Rapids. "Does it hurt the environment? I'm not at all convinced." Commissioner Darrell Hanson is also skeptical about what a ban on manure application to land going to soybeans would accomplish.
Currently, most farmers do not apply liquid swine manure to soybean ground. It's applied mostly to land that is going to be planted to corn.
The EPC didn't look at scientific studies in Iowa showing that soybeans will use nitrogen from manure first before fixing nitrogen from the air. "It's unfortunate that the EPC chose to ignore scientific studies, including studies by USDA researchers and scientists at Iowa State University," says Rick Robinson, environmental policy specialist for the Iowa Farm Bureau.
EPC is ignoring scientific advice
"There was an Iowa State University scientist sitting in the room at the EPC hearing—Dr. John Sawyer, an Extension agronomist and soil fertility specialist," notes Robinson. "But the EPC didn't seem to want to ask him questions."
The EPC also didn't discuss correspondence sent by Wendy Wintersteen, dean of the ISU College of Agriculture, and five ISU researchers who are leaders in the crop nutrient field. The letter was sent to DNR Director Jeff Vonk and can be found at www.extension.agron.iastate.edu/immag/prmn.html
The letter points out that "Research in Iowa and Minnesota has documented increases in soybean yields with application of liquid swine manure, when a response to nutrients would not be expected."
The researchers said an alternative to a ban is to restrict nitrogen applications on soybean ground to a range of 100 lbs. per acre. Soybeans, they said, would then compensate for any shortage of N by fixing the N from the air.
This would balance potential environmental concerns with the desire to maximize yields, while also allowing for additional manure application options. Robinson says the EPC's decision to ignore the ISU specialists' recommended alternatives is disappointing. "They chose to go forward with a proposed ban when ongoing ISU research is not complete," he notes.