A state official in charge of monitoring livestock confinement operations will ask the Iowa Environmental Protection Commission to appoint a work group that will consider a new rule for where the liquid manure that comes from those confinements may go. Wayne Geiselman of the Iowa Department of Natural Resources says it’s part of a long-term discussion about whether nitrogen-rich liquid manure should be applied to soybean fields.
Geiselman says soybeans don’t need the added nitrogen that comes from liquid manure because soybeans convert or “make” nitrogen themselves from the air or the nitrogen that already exists in the ground. The concern is excess nitrogen may run-off into nearby streams. “If you have wet conditions, you’re going to get leeching through the soil, to tile lines and potentially on into rivers and streams,” Geiselman says.
About half of the manure management plans on file with the state identify soybean fields as “potential” sites for application of liquid manure. “My gut feeling is certainly not all of those get that, particularly now — this year,” Geiselman says. “The price of commercial nitrogen is somewhere over $500 per ton and it becomes very cost-prohibitive to apply nitrogen where it’s not absolutely necessary for crop growth.”
The Iowa Environmental Protection Commission meets Monday and this issue is on their agenda.