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Agricultural Revolutions

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While food issues as political activism get nowhere the attention among liberals that it did a decade ago (remember the Michael Pollan for Obama’s Secretary of Agriculture boomlet in late 2008?), our food supply is deeply unsustainable. I am skeptical of most agricultral innovations in this sense because while they have consistently done a great job of feeding people in the short term, over the long term (which in terms of the planet can only be measured in terms of centuries, which is also the way to properly measure long term impacts for humans as a species), they have consistently led to a degraded environment. So color me skeptical, but still, there’s not much to do about our agricultural problems other than figuring out large-scale solutions, for the reality of the world is that locally produced food is just not scalable for the population at large, farmers markets notwithstanding. So this is interesting, at the very least.

In the 1980s, Howard-Yana Shapiro, now chief agricultural officer at Mars, Incorporated, was looking for new kinds of corn. He was in the Mixes District of Oaxaca in southern Mexico, the area where the precursors to maize (aka corn) first evolved, when he located some of the strangest corn ever seen. Not only was it 16 to 20 feet tall, dwarfing the 12-foot stuff in American fields, it took six to eight months to mature, far longer than the 3 months needed for conventional corn. Yet it grew to those impressive heights in what can charitably be called poor soil, without the use of fertilizer.. But the strangest part of the corn was its aerial roots–green and rose-colored, finger-like protrusions sticking out of the corn’s stalk, dripping with a clear, syrupy gel.

Shapiro suspected that those mucousy fingers might be the Holy Grail of agriculture. He believed that the roots allowed this unique variety of corn, dubbed Sierra Mixe and locally bred over hundreds or even thousands of years, to produce its own nitrogen, an essential nutrient for crops that is usually applied as fertilizer in epic amounts.

The idea seemed promising, but without DNA tools to look into the specifics of how the corn was making nitrogen, the discovery was shelved. Nearly two decades later, in 2005, Alan B. Bennett of the University of Davis—along with Shapiro and other researchers—began using cutting-edge technology to look into the nitrogen-fixing properties of the phlegmy corn, finding that indeed, bacteria living in the mucus were pulling nitrogen from the air, transmuting it into a form the corn could absorb.

Now, after over a decade of field research and genetic analysis, the team has published their work in the journal PLOS Biology. If the nitrogen-fixing trait could be bred into conventional corn, allowing it to produce even a portion of its own nitrogen, it could reduce the cost of farming, reduce greenhouse gas emissions and halt one of the major pollutants in lakes, rivers and the ocean. In other words, it could lead to a second nitrogen revolution.

But we can’t just quit nitrogen without seeing major reductions in agriculture. While better management and farming practices can help keep it out of waterways, those strategies aren’t enough to fix nitrogen’s ecological problems. That’s why researchers have for decades wondered if there was a way to help cereal crops like corn and wheat produce their own nitrogen.

The idea is not as farfetched as it sounds. Lots of plants, in particular legumes like soybeans, peanuts and clover, have a symbiotic relationship with Rhizobium bacteria, which produce nitrogen for them. The plants grow root nodules where the bacteria take up residence and sip on plant sugars while converting nitrogen in the air into a form the plants can use. If a similar symbiotic relationship could be found that works in cereal crops like corn and wheat, researchers believe we could reduce our use of the pollutant.

That’s why the mucus corn is so important, and why Bennett and his team spent eight years studying and re-studying the bacteria and gel to convince themselves that the corn was indeed able to produce its own nitrogen. Using DNA sequencing, they were able to show the microbes in the slime carried genes for fixing nitrogen and demonstrated the gel the corn excretes, which is high sugar and low oxygen, is perfectly designed to encourage nitrogen fixation. Using five different tests they showed that the nitrogen produced by the microbes then made its way into the corn, providing 30 to 80 percent of the plant’s needs. They then produced a synthetic version of the slime and seeded it with the microbes, finding that they produced nitrogen in that environment as well. They even grew Sierra Mixe in Davis, California, and Madison, Wisconsin, showing that it could perform its special trick outside its home turf in Mexico.

“This mechanism is totally different from what legumes use,” Bennett says, adding it may exist in other crops as well. “It’s certainly conceivable that similar types of systems exist in many cereals. Sorghum, for example, has aerial roots and mucilage. Maybe others have more subtle mechanisms that occur underground that could exist more widely. Now that we’re aware, we can look for them.”

Co-author Jean Michel-Ane from the University of Wisconsin, Madison, agrees that this discovery opens up all types of new possibilities. “Engineering corn to fix nitrogen and form root nodules like legumes has been a dream and struggle of scientists for decades. It turns out that this corn developed a totally different way to solve this nitrogen fixation problem. The scientific community probably underestimated nitrogen fixation in other crops because of its obsession with root nodules,” he says in a statement. “This corn showed us that nature can find solutions to some problems far beyond what scientists could ever imagine.”

There are plenty of reasons to be skeptical: another product stolen from indigenous people for whites to profit off, the involvement of the Gates foundation, the technological futurism at the heart of many of our problems. But again, what can we do at this point but try? It’s not as if the status quo can last.

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