EPC Limits Manure Application on Soybeans

State environmental commission also votes to put Iowa on the way to ban the practice.

After more than two years of discussion, the Iowa Environmental Protection Commission voted in March to limit the application of manure on land going into soybean production. They agreed to limit the amount of manure that can be applied per acre. However, the agreement reached by EPC also leaves the door open for a possible ban on the practice in five years.

The EPC is a nine-member citizen advisory board that helps set rules and policy for the Iowa Department of Natural Resources to carry out Iowa's environmental laws. Seven commissioners were present to vote and the vote was 5 to 2 to limit the amount the amount of nitrogen as manure that can be applied.

"The decision pleased few on either side of the debate, but it is a compromise between the two opposing sides on this issue," says Dave Petty, an Eldora farmer, livestock producer and chairman of the EPC. While he's glad the committee was able to reach a compromise, he and many other farmers in Iowa are concerned that in five years there could be a ban.

Leaders of Iowa Citizens for Community Improvement, an organization that wants stronger regulation of manure application, issued a press release after the EPC vote expressing displeasure that the ban will not automatically go into effect after five years but will instead come up before the EPC again for another vote.

First proposed two years ago

The proposal to ban or limit manure application on land to be planted to soybeans first came up for discussion two year ago when former EPC chairman Francis Thicke, a farmer from Fairfield, proposed a ban on applying manure to soybeans.

He argued that soybeans don't need the nitrogen that is available in manure because beans are a legume crop that makes a good share of it's nitrogen from the air, although beans get some N from the soil, too. Thicke believes manure application is unnecessary for beans and adds to the amount of nitrogen getting into streams and groundwater.

The decision EPC made in March is a compromise to reduce the amount of manure allowed to be applied to land under manure management plans. Manure management plans are required by the Iowa DNR of all confinements of more than 500 animal units or all open feedlots of more than 1,000 animal units.

New rule sets lower limit

Previously, DNR manure plans allowed a manure nitrogen application rate based on 3.8 lbs. of N per bushel of soybeans expected to be harvested. With a reasonable soybean yield of 50 bu. per acre this application would approach 200 lbs. of N per acre. The new rule now lowers that level to 100 lbs. per acre for soybeans.

Iowa State University's recommendation is that as much as 100 to 125 lbs. of nitrogen from manure would be a reasonable amount to apply per acre for soybeans. Soybean plants can compensate if there's a shortage of N supply from the soil, or applied manure, by fixing N. Using this moderate rate for manure planning, rather than eliminating the option to apply manure, is a workable approach, says John Sawyer, ISU Extension soil fertility specialist.

The new rule applies only to manure, not to commercial fertilizer, and very few farmers apply manure to land going to soybeans, notes Ralph Klemme, a farmer from LeMars and an EPC commissioner. Most farmers apply manure to land going to corn.

The new rules still include the ban on applying manure to beans after five years, but an amendment approved by the EPC requires the board to review the matter six months before the end of the five year period. The board must then vote again whether or not to proceed with the ban.

The five commissioners who support the new rules say these rules are necessary even though they may not have a large impact on water quality. Commissioner Susan Heathcote of Des Moines says, "We do have a nitrogen pollution problem in Iowa and this is a logical place to start—even though the amount of acreage in the state where manure is applied to soybeans is relatively small."

New rule affects manure management

Regarding the potential ban, EPC members on both sides of the issue pushed hard for their position—to either pass the proposed ban or stop it.

Those commissioners who support the idea of having a ban say it would help clean up Iowa waters. Commissioners Petty and Klemme, who oppose a ban, hope the five-year deadline will prompt farm groups in Iowa to fund more research into finding out what the environmental effects really are of manure application to ground going to beans.

The new rule must go to a legislative rules committee of the Iowa Legislature before it can become law. Once approved by that committee, it could become law by mid-May. Farmers who have an NRCS and DNR-approved manure management or nutrient management plan would then be required to make sure their plan meets the new guidelines regarding the limit on amount of manure that can be applied to soybeans.

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