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Fixing Nitrogen

The conversion of atmospheric nitrogen to ammonia is the key to the making of fertilizer. The current method relies heavily upon petroleum as a feedstock for the process, and the prospect of declining oil supplies has left some people worried about the viability of fertilizer-based agriculture. As we mentioned recently, an alternative feedstock from algae is now being studied. Now researchers at the University of Oregon have come up with a method of fixing nitrogen that can be done at room temperature and pressure (unlike the traditional process) -- potentially a more environmentally benign and simpler process than the current method. The article in the upcoming Journal of the American Chemical Society is online, but requires subscription, etc.

As usual, this is an experimental process taking years to get to commercial application, if ever. But it's also a good sign that peak-oil fears of the collapse of agriculture are probably unwarranted -- to whatever degree industrial agriculture can't shift to a fertilizer-free organic process, there look to be multiple possible alternatives to oil-based fertilizer.

Comments (5)

I'm not as familiar with this as I ought to be. I'm guessing that argibusiness is too optimized towards petroleum-based fertilizer to return to the bird, lifestock and bat guano fertilizers of earlier centuries?

It's a tough problem. Going back to bat guano doesn't help much with today's population. If memory serves, of the nearly 6 billion people on Earth today, synthesized nitrogen creates the protein keeping about 1.75 billion of them alive. A lot of this is due to diets rich in grain-fed meat.

It's heartening to learn about this research. Thank you Jamais. (Meanwhile, we're trying to limit our meat consumption to pasture-raised and local, or obtained by rod or gun.)

Philip Bogdonoff:

Richard Heinberg's latest essay addresses how dependent our predominant agricultural and food distribution systems are on fossil fuels. See


Threats of Peak Oil to the Global Food Supply - A paper presented at the FEASTA Conference: "What Will We Eat as the Oil Runs Out?", June 23-25, 2005, Dublin Ireland

Here's an excerpt that partly answers the question posed by Mr. Farlops --

"By the nineteenth century these limits were beginning to become apparent. Famine and hunger had long been common throughout even the wealthiest regions of the planet. But, for Europeans, the migration of surplus populations to other nations, crop rotation, and the application of manures and composts were gradually making those events less frequent and severe. European farmers, realizing the need for a new nitrogen source in order to continue feeding burgeoning and increasingly urbanized populations, began employing guano imported from islands off the coasts of Chile and Peru. The results were gratifying. However, after only a few decades, these guano deposits were being depleted. By this time, in the late 1890s, the world's population was nearly twice what it had been at the beginning of the century. A crisis was again in view.

But again crisis was narrowly averted, this time due to fossil fuels. In 1909, two German chemists named Fritz Haber and Carl Bosch invented a process to synthesize ammonia from atmospheric nitrogen and the hydrogen in fossil fuels. The process initially used coal as a feedstock, though later it was adapted to use natural gas. After the end of the Great War, nation after nation began building Haber-Bosch plants; today the process produces 150 million tons of ammonia-based fertilizer per year, equaling the total amount of available nitrogen introduced annually by all natural sources combined."

-- Philip B. / Washington, DC


Just wanted to comment that the energy intensity of the process is the biggest, but not the only problem with manufactured nitrogen.
There is also the fact that pure fertilizer, the way it is used in industrial farming, puts down more nitrogen over a larger area than can be used. It also adds no organic matter to the soil. This means increased pollution from runoff and increased sedimentation from erosion - leading to thinner topsoil and therefore more need for nitrogen. Spiral downward.

However - I still think this is great news and potentially very important; if a less expensive and energy intensive way to manufacture fertilizer becomes common, in addition to being more ecological, it would be withing the reach of organic farmers, and would help keep organic yields high - something necessary if we are to transition to a more localized food system.


Vaclav Smil, one of the greats of environmental chemistry, points out that there are three main global sources of fixed nitrogen, all of copmparable order of magnitude:

1) All the lightning in the world

2) All the Haber-Bosch plants in the world

3) A few tens of kilograms of the enzyme nitrogenase, working quietly at ambient temperature and pressure in nitrogen-fixing bacteria (in the world's pastures of clover, legumes etc.) and algae (in the world's rice paddies). IOW, picograms or femtograms per acre.

Obviously, learning to duplicate what that enzyme does -- or at least to get those bateria and algae to flourish in other setttings, in conjunction with other food crops -- has long been a grail of biochemistry, then biotech, and now genetic engineering. Nobody I know would say we're close. So your caution is justified; still, it's nice to know there's room for improvement.


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