In retrospect, a Wisconsin cornfield in mid-September 2018 wasn’t exactly the best place for an academic seminar. It was hot. There were horseflies. The sun cast a glare on the white poster boards, and the metallic chunk-chunk-chunking of a nearby grain elevator made it difficult at times to hear the main speaker. He was Walter Goldstein, a soft-spoken man in his mid-60s who had invited about 30 researchers and farmers to this field to make a point: Corn could thrive with little to no nitrogen fertilizer.
“We’re using too much nitrogen,” Goldstein said. “It’s polluting all of our water … It’s polluting the Mississippi. It’s just awful, and yet we need it in order to get the yields.”
Goldstein, an agronomist and the founder and executive director of the nonprofit Mandaamin Institute in Lake Geneva, Wisconsin, said he’d been breeding corn under low-fertilizer conditions for decades. He asked one of his assistants to hold a poster board with a blown-up photo of rows of corn. “Can you see the color differences here?” Goldstein asked. On one side of the photo were the rows of corn he’d bred, noticeably more vibrant and deeper green than the rows of commercial corn planted on the other side. This deep color indicated the plants were getting abundant nitrogen, a fundamental element they need to grow and make chlorophyll, the green pigment necessary for photosynthesis.
Although commercial corn typically gets some nitrogen from decayed organic material in soil, it mainly gets it from fertilizer — either organic, such as manure, or inorganic, such as ammonia — spread by the farmer (See “A Century of Ammonia,” opposite page). Goldstein said he hadn’t added fertilizer to his greener crops, though. Instead, he had cultivated varieties that would team up with microbes that process, or “fix,” nitrogen into a form usable by the plants.
