A new study released today by the US Geological Survey shows that efforts to reduce nitrate levels in the Mississippi River Basin are having little impact. Nitrates come mostly from the over-application of chemical fertilizers on crops in the Corn Belt, fouling streams and rivers and eventually helping to swell the annual Gulf of Mexico "Dead Zone."
Corn lobbyists have been citing an analysis they commissioned in a bid to show that agriculture is not the source of nitrogen pollution in the Mississippi River Basin, despite scientific evidence to the contrary, the Environmental Working Group charged.
"Gulf fishermen and residents all along the Mississippi River Basin must endure this insult to their water while the culprits continue to deflect blame. It is time for the corn lobby to acknowledge that their cropping system is a major source of water pollution and take responsibility for it," said EWG analyst Andrew Hug.
Large industrial grain operations blanket their fields with nitrogen fertilizer and animal manure. They help push an average of 164,000 metric tons of fertilizer down the Mississippi River into the Gulf each year, creating a low-oxygen Dead Zone of more than 6,765 square miles – an area larger than the state of Connecticut, EWG said.
The excess nitrogen triggers massive blooms of algae that block sunlight and ultimately die off, consuming oxygen and driving out or killing marine plants and animals.
The corn lobby's study concludes that corn production can't possibly be causing the pollution problem because all of the nitrogen applied ends up in the corn, not in the water. However, that conclusion is based on an outdated figure for the protein (and therefore nitrogen) content of modern hybrid corn, the EWG study found. In the past, corn tested at 10 percent protein, but current measurements indicate that corn's protein content has dropped 20-30 percent.
Corn lobbyists have long blamed others for the nitrogen pollution in the Mississippi River Basin, pointing the finger at urban lawns, golf courses and sewage treatment plants. But a previous USGS survey found that more than 70 percent of the nitrogen comes from agriculture, 52 percent from corn and soy production alone, EWG said.
Corn is the United States' largest and most subsidized crop, pulling in $77 billion in taxpayer dollars since 1995.
Today's USGS study details that nitrate transport to the Gulf of Mexico was 10 percent higher in 2008 than in 1980 and that none of the eight monitoring sites monitored showed any progress in nitrate reduction.
"The new USGS data clearly shows that we are making little progress in addressing nitrogen pollution in the Mississippi River Basin. Instead of putting out faulty studies and blaming others, it is time for the corn growers to end the cop out and actually become the environmental stewards they claim to be. Taking responsibility for their actions would be a welcome first step toward restoring Mississippi River water quality," said Hug.