Saturday, June 5, 2010
A Brief History of Chemical Fertilizers
A quick science lesson: Nitrogen is essential for life. From nitrogen, nature can create amino acids, proteins, and nucleic acids. However, the amount of nitrogen on earth is limited. Even though the earth's atmosphere is 80% nitrogen, all of the atoms are tightly paired and nonreactive: useless. In order to "fix" the element, the atoms must be split and joined to the atoms of hydrogen. Until 1909, the only two ways to "fix" the element were by soil bacteria living on the roots of leguminous plants (i.e. peas) or by the shock of electrical lightning. Without a man-made fix, the population of earth would have come to a halt, which is why the Haber-Bosch process is considered one of the most important inventions of the twentieth century and why Fritz Haber won the Nobel Prize.
So what does this mean for our food? When we began to "fix" nitrogen, we no longer relied on the sun, but on fossil fuels. The Haber-Bosch process combines "nitrogen and hydrogen gases under immense heat and pressure in the presence of a catalyst. The heat and pressure are supplied by prodigious amounts of electricity, and the hydrogen is supplied by oil, coal, or, most commonly today, natural gas-fossil fuels." The use of ammonium nitrate as a fertilizer became widespread in the 1950s. Instead of a local, sun-driven cycle, farmers could plant corn every year and on as much land as he wanted since he no longer needed legumes or animal manure. Instead of eating from a natural cycle dictated by the sun, we began eating petroleum. "When you add together the natural gas in the fertilizer to the fossil fuels it takes to make the pesticides, drive the tractor, and harvest, dry, and transport the corn, you find that every bushel of industrial corn requires the equivalent of between a quarter and a third of gallon of oil to grow it- or around fifty gallons of oil per acres of corn," though some estimates are much higher.
Another problem is that the farmers tend to pollute with their fertilizers, either because it's applied at the wrong time, it runs off, or because they applied too much "just to be safe." On George Naylor's farm, he sprays an excess of one hundred pounds of synthetic nitrogen that either ends up evaporating (acidifying the rain and contributing to greenhouse gases) or in the water supply in Iowa. In Iowa, there are special faucets where you receive your water. Not simple purifiers like most Americans have in their homes, but a reverse-osmosis filtration system. During certain times of the year in Des Moines (and other cities), "blue baby alerts" are issued by the city to warn that it's unsafe for children to drink the tap water because the nitrates convert to nitrite, which binds to hemoglobin, and compromises the blood's ability to carry oxygen to the brain. If you think it only affects states like Iowa, you're wrong. The nitrates flow into the Mississippi River and into the Gulf of Mexico where it creates Dead Zones. Other notable dead zones are in the Pacific Northwest and off the coast of Virgina.