By Lacie Armstrong
A rare variety of corn discovered in 1980 by Howard-Yana Shapiro, whom is now chief agricultural officer at Mars, Incorporated, makes its own mucousy fingers that produce its own nitrogen. The corn was described as “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”. It grew to the impressive height, even in poor soil and no fertilizer, was due to the aerial roots–green and rose-colored, finger-like protrusions sticking out of the corn’s stalk, dripping with a clear, syrupy gel. The gel has so much nitrogen, which is an essential nutrient for crops that is usually applied as fertilizer in epic amounts.
Nearly two decades later, in 2005, Alan B. Bennett of the University of California, 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.
Pros of Synthetic Production of Nitrogen
One discovery shows the process and its refinements, in which nitrogen is stripped out of the air under high heat and pressure in the presence of a catalyst, has led to three separate Nobel prizes. It’s estimated that crop yields more than doubled between 1908 and 2008, with synthetic nitrogen fertilizer responsible for up to half that growth. Some researchers have tied the massive growth in human population in the last seventy years to the increased use of nitrogen fertilizer. Without it, we’d have to farm almost four times as much land or have billions of fewer people in the world.
Dangers of Producing Nitrogen
Producing nitrogen has consequences. It’s estimated that making fertilizer via the Haber-Bosch process uses between 1 and 2 percent of the world’s energy, emitting lots of greenhouse gases. Synthetic nitrogen routinely washes off fields into waterways, leading to massive algae blooms that suck up all the oxygen, killing fish and other organisms. So much nitrogen goes into rivers and streams that large dead zones have developed everywhere.
Why We Can’t Quit Nitrogen
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.
Solutions
While it’s unlikely that one solution alone will be able to replace 100 percent of the synthetic fertilizer humans use, its important research is still continuing on to contribute to the nitrogen revolution. Shapiro admits “it’s a very long leap before his slimy corn fingers start producing nitrogen in conventional crops”. He now wants to identify the genes that produce the aerial roots and pin down which of the thousands of microbes discovered in the mucilage are actually fixing the nitrogen.
“I think what we’re doing could be complementary to those [endoyphyte and synthetic biology] approaches,” he says. “I think we’ll see many divergent strategies, and in 5 to 10 years something will emerge that impacts how corn gets nitrogen.”
