Mandating measures to control and reduce chemical pollution from farm fields should begin, University of Iowa water quality researchers say.
But, don't expect Iowa's land-grant agricultural institution – Iowa State University – to join the call for regulation or any government measures to limit the use of fertilizer on ag land.
Researchers at the University of Iowa Hydroscience and Engineering Department have been analyzing farm field runoff of nitrogen and phosphorus for decades.
They say the evidence is clear: pollution from excess fertilizer has risen more than 100 percent over the past 16 years despite a Nutrient Reduction Strategy (NRS) goal to reduce nitrate runoff from farm fields by 45 percent.
The NRS was crafted by Iowa State University, the Iowa Department of Agriculture and Land Stewardship (IDALS) and the Iowa Department of Natural Resources.
Big ag interests, including the Iowa Farm Bureau, the Iowa Corn Growers Association and the Iowa Soybean Association have been strong supporters of the NRS, which was notable in recommending an entirely voluntary approach to lower nutrient runoff.
University of Iowa researchers monitor streams in all Iowa watersheds and the results have laid bare the lack of progress on reducing nutrients that foul state streams, river and lakes. A voluntary approach, they say, will never achieve the goal to reduce pollution from state farm fields.
Here's what University of Iowa hydrologists recommend to actually lower nutrient runoff from Iowa farm fields:
- Eliminate fall application of anhydrous ammonia (nitrogen) and fall tillage on soybean stubble.
- Place a moratorium on new CAFO's (Confined Animal Feeding Operations) and tile drainage upgrades until nitrogen loads show a reduction.
- Require that nitrogen application rates accurately account for Manure-N (nitrogen), and in total, do not exceed 110 percent of Maximum Return To Nitrogen (MRTN) rates. Or, alternatively, apply a luxury tax to fertilizer in excess of MRTN.
- Adopt nutrient standards for lakes and protect lakes after lake restoration programs.
- Fund Iowa's Water and Land Legacy while preserving the formula.
- Develop digital, geospatial system to map land in manure management plans, and thereby reduce the number of field parcels in multiple plans.
- Discontinue row crop production on 100,000 acres of the 2-year flood plain (275,000 acres).
While not disputing their University of Iowa colleagues' nutrient runoff findings, Iowa State researchers say their role is to educate farm operators, not regulate their operations.
"Our involvement with the NRS was to put together practices that would be the most effective," Matthew Helmers, Director of the ISU Nutrient Reduction Strategy Center, said. "We studied the different scenarios, the scale of the process needed for change and provided that information to state agencies. We need tremendous implementation of the recommended practices to reach those goals."
Those recommended practices include installing bio-retention basins, wetland restoration, use of cover crops and setting aside additional acres for conservation reserve. With 33 million acres of crop land in the state, environmental groups point out it will take hundreds of years at current adoption rates to reach the level of conservation practices needed to achieve the report's nutrient reduction goals.
The role of the university is to educate farm operators on practices they can use to reduce nutrient run-off, said Helmers.
"I think we've certainly developed the NRS non-point component, laid out the challenges faces by agriculture and point out the opportunities for improvement," Helmers said.
