Nitrate pollution affects communities in Iowa ranging from the state’s largest cities to “many of its smallest,” says the Des Moines Register, “evidence of a contamination problem that reaches across the state.” The Register says 60 cities and towns “have battled high nitrate levels in their drinking water over the past five years,” according to state environmental data. Many communities do not have facilities to remove excess nitrates from drinking water. The issue gained prominence earlier this year when the Des Moines Water Works sued drainage districts in three upstream counties on grounds that tile lines from farm fields exacerbate nitrate pollution.
Nitrates in waterways can come from various sources, including agricultural fertilizer, septic systems and naturally occurring nitrates leaching from soils.
In Ohio, three dozen farmers in the Toledo area are part of an experiment in drawing daily samples of water from streams and recording agricultural activities in nearby fields. “The goal is to provide a picture of how the phosphorus leaching from the farm corresponds to the farmer’s choices,” says Modern Farmer. A parallel project by Ohio State U looks at revisions to guidelines on fertilizer application.
“Together, the teams have been developing an online tool that will allow farmers to enter weather information and other metrics on a smartphone and receive an instant, custom-tailored report on how to apply just the right type of phosphorus product in the right amount at the right time in the right way—what agronomists refer to as the “Four Rs” of fertilizer,” says Modern Farmer.