Two Universities to Research Fertilizer Impact on Water Quality

The Responsible Industry for a Sound Environment (RISE) and its member companies are sponsoring two separate university studies on the effects of specialty fertilizer to urban water quality.

The studies, each slated to take three years, will cost a combined amount of approximately $310,000. These experiments will help identify sources of nutrients that may be contributing to surface water pollution.

“We know lawn fertilizers applied to turf are not generally responsible for the amounts of excess nutrients (phosphorus and nitrogen) found in our nation’s water bodies as claimed by activists,” commented Jim Skillen, RISE manager of Formulators’ Issues. “Natural sources such as leaves, pollen, soil erosion, flower parts, pet and water fowl waste contribute significantly to high phosphorus levels in urban lakes, ponds and rivers.”

Skillen observed that there has not been enough documented research to counter the unsubstantiated claims of activists. In 2002, Minnesota passed a law banning the use of fertilizers containing phosphorus in six metropolitan areas and limiting non-metro counties to three percent phosphorus content for fertilizers. Iowa, Missouri, New York and other state legislatures may also consider regulating specialty fertilizer use.

To determine the levels of phosphorus and nitrogen from natural sources versus lawn fertilizer, the University of Minnesota and Cornell University will conduct separate experiments in accordance with proper scientific method.
University researchers from Minnesota will document and evaluate phosphorus runoff from urban turf.

The three-year study, headed by Dr. Brian Horgan, will quantify the source and amount of phosphorus and nitrogen in runoff from lawns as well as identify management techniques that will minimize this runoff. Twenty-four runoff plots will be constructed and manipulated to create different nutrient experiments. Eight different treatment scenarios will be monitored using variables such as grass clippings, phosphorus fertilizer, nitrogen fertilizer, organic fertilizer and no fertilizer. In addition, these runoff plots will measure what actually runs off of a fertilized lawn after a rain event. An irrigation system will be installed to simulate rainfall in the absence of natural rainfall events. Each of the eight treatments will be replicated three times to ensure accuracy.

Cornell University will also conduct experiments to help define the residential landscapes’ impact on suburban runoff. The results of this study, led by Dr. Martin Petrovic, will further the understanding of how various residential landscape types influence the different nutrient levels found in urban runoff. The study site will be composed of three landscape types: a well maintained lawn, a poorly maintenance lawn and a primary treed/woody vegetation landscape. Each of the three landscapes will reflect a typical residence by having a house and driveway on the premises. The volume of runoff leaving each landscape will be determined and the runoff will be sampled and analyzed for nutrient content.  These samples will provide a detailed comparison of the different residential landscape types.