The Iowa Department of Natural Resources says crop producers who have applied liquid manure to fields based on planting corn can switch to soybeans without worrying about penalties for exceeding nitrogen limits on the field. “Normally, there’s a 100-pound per acre limit on nitrogen applications on soybean fields for crop producers who obtain the nitrogen from liquid manure,” said Ken Hessenius, supervisor of the DNR field office in Spencer. “But producers who planned to plant corn and applied liquid manure at higher rates may safely switch the crop to soybeans after June 1 without concern about a penalty,” he added. “That’s one small piece of good news during a wet, cold spring that has delayed corn planting.” 

The 100-pound available nitrogen limit applies to ground where soybeans have been planted, are growing or will be the next crop growing in the field. The restriction applies to liquid manure coming from livestock facilities that are required to have a manure or nutrient management plan. “If the planned crop is switched from corn to soybeans, the producer needs to put a note in the their manure or nutrient management plan about why they applied manure for corn and are now planting beans,” Hessenius added. “That will ensure there are no questions when the DNR inspects their records.” 

However, the 100-pound limit is no longer applicable after June 1 based on the assumption that crop producers may have to make changes in planned crops because of the weather. For more information, see the DNR website at www.iowadnr.gov/afo/