Some Iowa researchers say that we must face the facts that farm practices are the central source of applied pollutants in Iowa waterways, and that policy measures need to focus on agriculture.
“We need to get past people trying to shift our focus to smaller sources of pollution. Our central challenge to clean water in Iowa is, without question, our agricultural practices,” declared David Osterberg, executive director of the nonpartisan Iowa Policy Project (IPP) and a former chair of the agriculture committee in the Iowa House. “Iowa policy makers must not allow themselves to be distracted.”
But fertilizer interests say not so fast, because while there is merit in IPP’s findings, the report misses the point by confusing fertilizer with nutrient losses, adding that plants take up much of these nutrients as they grow.
IPP focuses on nutrient pollution in the Mississippi River Drainage Basin by targeting fertilizer application timing and ground cover, which affect whether the nutrients are used as intended to increase crop yield, or become unhealthy and cause water pollution. To co-author Will Hoyer it’s clear that the main culprits are nitrogen and phosphorus applied to agricultural land, and that’s where environmental policy must focus in both rural and urban settings.
“What is being done now is not enough. Pollution is outpacing current approaches,” Hoyer said. “We need new rules to require or incentives to encourage better practices. Strategies must consider the planting of cover crops, nutrient testing, conservation tillage, and adherence to well-developed nutrient-management plans.”
The report looks at various land uses, finding that 96 percent of N went to corn ground, 2 percent to soybean fields, and less than 2 percent to residential lawns or golf courses. About 86 percent of P was to corn ground and almost 12 percent to soybean fields, with less than 2 percent to residential lawns or golf courses. “While on average, households and golf course operators apply both nitrogen and phosphorus at greater rates per acre, their impact is minimal due to the small amount of acreage receiving applications,” according to the report.
The Fertilizer Institute (TFI) responded that there is merit in the report’s call for increased incentives for nutrient management and conservation practices. “(But) we take strong exception to the broad brush the authors use to assign blame to farmers and their fertilizer use,” TFI stated. “Fertilizer use should never be confused with nutrient losses as growing plants take up much of these nutrients as they grow.
“Additionally, the report’s utilization of U.S. Geological Survey statistics is very flawed as the methodology USGS utilizes to determine nutrient losses is inappropriate for this purpose, and we have discussed this in great detail with USGS. Finally, the report mixes citations exclusively about manure application with language about fertilizer application, and for this reason seems to be a hastily assembled attempt to assign blame to farmers in what is a very complex situation.”