"
Dead zones occur throughout the world and persist through the summer until plunging water temperatures — and often
hurricanes —
mix oxygen back into the depths each fall. The hundreds of dead zones throughout the world cover nearly 100,000 square miles, with one in the Baltic Sea spanning more than 23,000 square miles several years ago. Collectively, nearly 10 million tons of biomass either moves from or dies in dead zones every year."
"
But dead zones can be reversed. After the collapse of the Soviet Union, nutrient runoff was reduced threefold to fourfold, eliminating a 15,000-square-mile dead zone off the northwest continental shelf of the Black Sea.
A dead zone in the Chesapeake Bay also has shrunk in recent years, Magnien said, because of major advances in wastewater treatment, sediment and storm water controls, soil management practices, and more selective and precise applications of fertilizer.
Matt Liebman, who studies cropping systems at Iowa State University, is hopeful that a shift in agricultural practices in the Midwest could make a big difference for the Gulf of Mexico. In a study published this year, his team showed that
runoff could be reduced by 60 percent if farmers growing corn and soybean rotated in one or two more crops."
"In addition to rotating crops, Liebman found, “less productive areas could be converted into crop and non-crop vegetation that provides conservation benefits.” A previous Iowa State study showed that
converting just 10 percent of farmland back to native prairie grass could reduce nitrogen and phosphorous runoff by nearly 90 percent.
“I’m optimistic that we have a lot of technical answers,” he said, but “we need a market pull and a
policy push.”
"Such policy changes could include
regulations,
financial incentives for farmers to adopt conservation practices, and
technical assistance to help farmers incorporate the changes."
The Gulf of Mexico dead zone is larger than ever. Here’s what to do about it. - The Washington Post
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Back in the 1940s in elementary school in Dallas, Texas, I was taught about the benefits of contour farming, and
crop rotation. Perhaps it is time for "modern farmers" to learn the same lesson.