Our other addiction: the tricky geopolitics of nitrogen fertilizer  

Grist has an article on the production of nitrogen based fertilisers - Our other addiction: the tricky geopolitics of nitrogen fertilizer.

We burn through more of it per capita than any other country; and our appetite for it can only be sated with massive imports.

No, not oil—I’m talking about nitrogen fertilizer. With only 5 percent of the world population, the U.S. consumes nearly 12 percent of the globe’s annual synthetic nitrogen fertilizer production. And we’re producing less and less of it at home—meaning that, as with petroleum, we’re increasingly dependent on other nations for this key crop nutrient.

In a sense, the answer to the question of where our food comes from is not some vast Iowa cornfield or teeming North Carolina hog factory. It’s places like the Port Lisas Industrial Estate on the Caribbean island nation of Trinidad and Tobago, where 10 natural gas-sucking ammonia plants produce about a quarter of the nitrogen fertilizer used by American farmers.

Nitrogen fertilizer production is tied directly to natural gas, the energy source used in the United States to synthesize nitrogen-rich ammonia from thin air. So you could also imagine our food coming from some vast natural gas deposit in the Gulf of Mexico or off of Trinidad. Nearly as much as grain elevators or supermarkets, off-shore gas rigs count as vital food-system infrastructure.

But as U.S. natural gas prices began rising early this decade, the domestic nitrogen fertilizer industry went into crisis. Producers either scaled up to gain efficiency, moved to countries with cheaper natural gas sources like Trinidad and Tobago, or simply shuttered plants.

The industry has flirted with the idea of switching to gasified coal as the energy source for N fertilizer. “Recent advances in using coal to produce ammonia have increasingly made this technology economically feasible, especially at high natural gas prices,” USDA analyst Wen-yuan Huang wrote in a 2009 paper [PDF]. “Domestic ammonia production based on coal may play a larger role in the U.S. nitrogen supply if economic conditions and environmental considerations are favorable.”

But so far, only one firm, North Dakota-based Dakota Gasification Company, makes a significant amount of nitrogen fertilizer with gasified coal. Another plant, Kansas-based CVR Industries, is making nitrogen fertilizer with yet another fossil-based alternative: gasified petroleum coke. Together, these companies generate about 5 percent of our domestically produced nitrogen. But these exotic inputs don’t seem to be on the verge of pushing out natural gas anytime soon, Janice Berry, a researcher at the Alabama-based fertilizer industry tracker IFDC, told me. “I know of no companies that plan to switch over,” she said. And that’s just as well, because moving to carbon-rich sources like coal and petroleum would only add to N fertilizer’s massive carbon footprint.

Instead, with natural gas prices high, the domestic industry has shrunk. Between 1999 and 2008, domestic nitrogen fertilizer production plunged nearly 40 percent, according to a USDA report [PDF]. But demand for nitrogen—the juice that keeps those big corn crops coming—rose steadily. To fill the gap, we now import more than half of the nitrogen we consume, compared to about 15 percent just a decade ago, the USDA report states.

So where does our nitrogen come from? Given our food system’s reliance on synthetic nitrogen, that’s another way of asking: Where does our food come from?