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The High Cost of Cheap Nitrogen

April 30, 2013
West Fertilizer Plant Explosion. Source: The New Yorker.

West Fertilizer Plant Explosion. Source: The New Yorker.

The explosion of the fertilizer factory in West, Texas, earlier this month was lost amid discussion of the Boston Marathon bombing. Yet the tragic explosion highlights some real problems in our food system.

The West Fertilizer Company was established in 1962, to produce ammonium nitrate used as fertilizer in agricultural production. When the plant exploded, more than 24 tons of ammonium nitrate were on hand. More than 15 people were killed and more than 140 were injured in the explosion, which also destroyed 60 homes. Initial investigations into the explosion found that despite a federal requirement that the Department of Homeland Security be notified of any ammonium nitrate stockpiles of more than one ton, West had not notified the department. The last inspection of the plant—conducted by OSHA in 1985—found five “serious” violations, including improper storage and handling of anhydrous ammonia and improper respiratory protection for workers. The company was fined $30 for its violations.

Nitrogen is a fundamental building block for plant life. Growing food requires nitrogen. But despite the widespread availability of nitrogen in the atmosphere, most plants are incapable of absorbing nitrogen directly and instead require nitrate drawn from the soil. And the quest to increase the levels of nitrate in the soil has been one of the fundamental challenges facing farmers since the start of agriculture. Even before we understood the chemical and physiological processes associated with nitrogen fixation, farmers understood that adding composed crop waste, cattle or pig manure, or later bat guano, to their fields increased their crop yields. But it wasn’t until after World War II, when nitrogen was produced on a massive scale for use in bombs and munitions, that synthetic nitrogen fertilizers came into widespread usage.

Since then, consumption of synthetic nitrogen has increased dramatically, particularly in the United States. Today, notes Tom Philopott at Mother Jones, the United States consumes about 12 percent of global nitrogen fertilizers, particularly in the use of corn production.

Source: Mother Jones

Source: Mother Jones

But the widespread use of synthetic nitrogen fertilizers has dramatic unintended consequences.

First, runoff from American farms carries nitrogen-rich soil down the Mississippi and into the Gulf of Mexico, where it facilitates the growth of algae blooms which create hypoxic (low-oxygen) areas, killing off other plants and animals. Such “dead zones” have been observed around the world, including an area of more than 6,500 square miles in the Gulf of Mexico. Other dead zones have been observed off the east and west coasts of the United States, in the Baltic Sea, and in the South China Sea.

Second, many climate scientists are concerned about the sharp increase in the levels of nitrous oxide in the atmosphere. Nitrous oxide is a greenhouse gas, and scientists at the University of California, Berkeley, believe that increased fertilizer consumption is the primary driver of recent increases. Indeed, according to one source,  “a steep ramp-up in atmospheric nitrous oxide coincided with the green revolution that increased dramatically in the 1960s, when inexpensive, synthetic fertilizer and other developments boosted food production worldwide, feeding a burgeoning global population.”

Finally, some scientists believe that the use of synthetic fertilizers may decrease the organic matter content of soil, creating a chemical treadmill. As Tom Philpott observes,

As organic matter dissipates, soil’s ability to store organic nitrogen declines. A large amount of nitrogen then leaches away, fouling ground water in the form of nitrates, and entering the atmosphere as nitrous oxide (N2O), a greenhouse gas with some 300 times the heat-trapping power of carbon dioxide. In turn, with its ability to store organic nitrogen compromised, only one thing can help heavily fertilized farmland keep cranking out monster yields: more additions of synthetic nitrogen.

All of this suggests that our dependence on cheap nitrogen to increase food production may come at a high cost.


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One Comment
  1. Reblogged this on Science on the Land and commented:
    argylesock says… Crops need nitrates. I like this article about how nitrate fertiliser can be a good thing gone bad. You might want to recall what my fellow blogger Janina at Food (Policy) for Thought wrote about nitrogen fertiliser You might also follow the links about eutrophication (excessive plant nutrients, including nitrates) in water, towards the bottom of my post about duckweed

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