Iowa is considering banning manure as a soybean fertilizer. The Iowa Environmental Protection Commission contends that adding manure to soybean crops causes an overflow of nitrogen to the fields and poses a water contamination risk.

The proposal is part of a long-term discussion about whether nitrogen-rich liquid manure should be applied to soybean fields. Some scientists contend that soybeans don't need the added nitrogen because soybeans convert nitrogen from the air or the nitrogen that already exists in the ground.

If approved, the board would address the proposal at public hearings before taking final action. The proposed rule would take effect over three years, and would allow exceptions for times when heavy rains force changes in planting plans.

Environmentalists say the ban will protect citizens from water contamination, while the agriculture community is against it. Many pork producers use the hog manure on cropland to cut down on fertilizer costs and as a way to dispose of the manure. A ban also would force crop producers to plant corn when the demand for soybeans is growing.

Sources: Associated Press, Des Moines Register