In America, corn syrup is king, and real sugar hovers somewhere around prince status. We’re addicted to corn, and corn, in turn, is addicted to nitrogen. A long time ago, people figured out that by rotating crops, the soil will stay nutrient-rich, which helps to an extent by retaining nitrogen. Then we figured out how to make nitrogen fertilizer, and through its use we essentially doubled the average crop yield over the last hundred years or so.
The aerial roots of the Sierra Mixe corn stalk help the plant produce its own nitrogen. Image via Wikimedia Commons
Not all plants need extra nitrogen. Legumes like beans and soybeans are able to make their own. But corn definitely needs nitrogen. In the 1980s, the now-chief of agriculture for Mars, Inc. Howard-Yana Shapiro went to Mexico, corn capital of the world, looking for new kinds of corn. He found one in southern Mexico, in the Mixes District of Oaxaca. Not only was this corn taller than American corn by several feet, it somehow grew to these dizzying heights in terrible soil.
Shapiro thought the corn’s success might have something to do with the aerial, finger-like roots protruding from the cornstalk. Decades later, it turns out he was right. Researchers at UC Davis have proven that those aerial roots allow the plant to grab nitrogen out of the air through a symbiotic relationship with bacteria in that clear, syrupy mucus. The process is called nitrogen fixation.
