AgriNews :
Nitrogen pollution flowing out of Iowa to the Gulf of Mexico has grown by close to 50 percent over nearly two decades, a new report shows, despite hundreds of millions of dollars spent to stem nutrients entering the state’s waterways.A University of Iowa study shows the state’s contribution to the Gulf dead zone spiked 47 percent to 618 million pounds in 2016, based on five-year running annual averages.“Just based on water quality data, I think we can say we’ve not made much progress over the past 20 years in terms of nitrogen,” said Chris Jones, a research engineer at the UI’s IIHR-Hydroscience &> Engineering.Environmentalists say the study raises new questions about the effectiveness of Iowa’s approach to improving water quality and its reliance on voluntary ag compliance.