The excessive spring rain this year is likely to generate a bumper crop, but not of corn and beans. Instead, massive flooding of heavily fertilized Midwest agricultural fields and record flow down the Mississippi and Atchafalaya rivers will carry nitrogen fertilizer to the Gulf of Mexico, where it will create perhaps the largest hypoxic dead zone in history.
“Dead zone” is a misnomer. When nutrients such as fertilizer enter surface water where there is abundant light for photosynthesis, it causes a massive bloom of tiny marine plants called phytoplankton. As phytoplankton die and sink, they are decomposed by bacteria, consuming massive amounts of oxygen.
Bottom-dwelling shrimp, crabs and fish either perish or flee the now-hypoxic area. The dead zone has varied in size, but it has averaged 5,806 square miles.
The Hypoxia Forecast predicts that it could be 67 percent larger this summer.
The National Oceanic and Atmospheric Administration estimates that hypoxia in the Gulf Coast costs the seafood and tourism industries a devastating $80 million-plus annually. This doesn’t include effects on drinking water and human health, which can cost billions of dollars.
The health of the Gulf of Mexico is intimately linked to farming practices hundreds of miles away. The Mississippi River drains 1,245,000 square miles in the middle of the United States, an area containing extensive corn production, where only 60 to 70 percent of the nitrogen fertilizer applied ends up in grain. Much of the rest is converted to highly soluble nitrate in the soil, dissolves, drains into streams and ultimately flows to the Gulf.
The equivalent of about 2,800 train cars of fertilizer flows down the Mississippi in one month.
Currently, fertilizer amounts are based on simple rules of thumb (1.2 pounds of nitrogen per bushel of expected corn yield), but those do not consider the variability of needs within a field. Overapplication of fertilizer in low-yielding areas, in particular, results in unnecessary economic losses for farmers and increases the likelihood of nutrient runoff into water bodies.
Recently, the University of Illinois hosted a “critical conversation” to take a fresh look at the problem. The conversation was inclusive: The lead scientist of one of the world’s largest agricultural companies was at the table with the nation’s most passionate environmental organizations working with the agricultural industry.
All participants recognized that conventional approaches to the problem have failed and that part of the solution may be found in emerging technologies.
Agribusiness companies are gathering “big data” from millions of acres of cropland at high frequency and high spatial resolution to develop improved recommendations for varying fertilizer application rates in a field. Sophisticated GPS-guided equipment can vary application rates, enabling farmers to make “smarter” decisions for fertilizing fields.
These technologies can increase the returns on land and reduce what ends up in the Gulf.
Additionally, rapid advances in precise genetic engineering could increase crops’ efficiency in nutrient absorption and use.
Recently, scientists studying corn in southern Mexico discovered plants living cooperatively with a bacteria that provided them with nitrogen from the atmosphere, thus reducing their need for fertilizer.
Using cutting-edge genetics to reduce reliance on fertilizer would be an enormous boost to farming.
The president’s executive order earlier this month directing federal agencies to streamline regulations on agricultural biotechnology, is a step in the right direction.
Farm runoff also causes large algal blooms in the Great Lakes and the Chesapeake Bay, and there are more than 400 dead zones globally.
Technology holds some promise for reversing this problem, as does rewarding farmers for improving practices.
In the end, however, we may need to treat farm runoff as a serious pollutant, regulate it accordingly and incentivize adoption of technological solutions to reduce dead zones.