Iowa farmers and other interested parties:

The Iowa Environmental Protection Commission recently asked for a ban on application of liquid manure from swine and cattle operations on land that would be planted to soybeans. They cited research conducted by respected scientists at Iowa State University as the main reason for their request. In this single study, a heavy application of manure was associated with high amounts of nitrate in water from tile lines under the field. Obviously (at least to the EPC) that means that applying manure to soybeans actually pollutes water.

And besides, manure, which contains significant amounts of nitrogen, is best used in a crop like corn, which needs significant amounts of nitrogen. Everybody knows soybeans can make their own nitrogen.

So, if hardly anyone does it and it’s not necessarily a good practice, why would any person or group oppose EPC’s decision?

In recent years, ISA has taken the stand that, come what may, we need to base decisions – all decisions, from production and management on the farm, all the way to government rules and regulations that affect our business – on sound science and logic.

In this case, we question both the science and the logic behind EPC’s proposed ban.

Science: While there has been a smattering of research in which manure was applied to soybeans, there have been no replicated, no historical, studies that reach the same conclusion as the one cited by EPC. In one study, nitrate was high in water from tile lines where excessive amounts of manure were applied prior to planting soybeans. In another study, a more reasonable application of manure actually increased soybean yields by 5 to 7 bu. per acre. Many of the ISU soil scientists who have looked at the research agree with ISA in concluding that more studies should be done before such a drastic action is taken.

Logic: No one actually knows how many acres intended for soybeans actually receive an application of manure in Iowa. After talking with a number of farmers about this issue, we believe that only a few actually do this. A large number of those do so with an approved 590 nutrient management plan. Right now, 590 rules allow them to apply considerably more nitrogen from manure than their soybean crop would likely use. If there is a potential water quality problem from use of manure on soybeans, it seems logical to us to adjust the allowances in nutrient management plans, rather than to ban the practice altogether.

We at the Iowa Soybean Association believe this proposed ban, based on minimal science and questionable logic, sets a dangerous precedent for future actions by appointed or elected regulators who may not have the best interest of farmers or groups of farmers at heart.

Whether you agree or disagree, we’d like to know what you think about this. If you’d like to share your view with us, please write to: Sound Science, Iowa Soybean Association, 4554 114th Street, Urbandale, IA 50322.

For more background on this issue, click on these links:

ISA Backgrounder / Position Paper - PDF
Letter To The Des Moines Register - PDF
ISU John Sawyer May 12 letter to the EPC - PDF
ISU Sawyer et al Sept. 14 letter to the EPC - PDF
Soybeans And Manure Go Well Together
ISU Tile Line Water Nutrient Study, Northeast Research Farm - PDF

Ray Gaesser
President
Iowa Soybean Association