Before Haber-Bosch, there were only two ways to get nitrogen out of the air and into food. One was lightning. But the most important one was the slow, steady process by which a few types of bacteria ate atmospheric nitrogen, broke it apart, and reformed it into substances plants could eat. The process is called bacterial nitrogen fixation. Some of these bacteria set up homes in nodules attached to the roots of plants, notably legumes like peas and beans, forming a symbiotic relationship in which they exchanged their fixed nitrogen for sugars and other food provided by the plants. These bacteria, working for millions of years, slowly built a stockpile of fixed nitrogen that fed most of the earth’s plants, which fed all the animals. Life on earth depended on that stock of fixed nitrogen.
Haber-Bosch turbocharged the process. Today, Haber-Bosch plants produce an amount of fixed nitrogen equivalent to that produced naturally, doubling the amount available on earth. While this massive change in natural cycles means little to the basic composition of the atmosphere -- there is so much N₂ in the air that the amount used by Haber-Bosch is negligible – it does mean a great deal to the biosphere, the places on the earth where life dwells....
Thursday, July 24, 2008
Thomas Hager: The Alchemy of Air
Thomas Hager shares an essay from his forthcoming book, The Alchemy of Air, which explores the implications of the 1909 invention of the Haber-Bosch process for creating nitrogen fertilizer. Without it, for better or worse, there would be no modern agriculture. Here is a sample.