Researchers find fertilizer runoff from soy and corn not as high as thought

In Iowa, IIHR—Hydroscience & Engineering researchers Chris Jones, Keith Schilling, and Kung-Sik Chan, along with colleagues at the Iowa Soybean Association, evaluated water monitoring results from more than 7,000 water samples collected in the Raccoon River watershed of Central Iowa from 1999-2014. The team also had access to fertilization data for 700 fields in the watershed. The information led the researchers to believe that nitrate levels are less dependent on corn production acres than previously thought. As more acres were planted in corn (and fewer in soybeans), fertilizer application increased a whopping 24 percent in the watershed. Interestingly, river nitrate did not increase and may have even decreased slightly at most watershed locations.