Haber Bosh for the 21st Century

Many loyal readers know that I’m interested in the problem of supplying enough fixed nitrogen for our staple crops (rice, corn, wheat), none of which can fix nitrogen on their own. We are utterly dependent upon these food systems. Currently our planet is 2 billion humans over its natural carrying capacity and it is fertilizer (fixed nitrogen) that keeps us alive. The Haber Bosh Process, invented at the beginning of the 20th century, was the genius killer app of science and industrial design that has, to date, secured our food systems.

Unfortunately, there are some downsides. For one thing, agricultural runoff of fixed nitrogen pollutes our waterways and leads to toxic eutrophication. For another, the industrial process required to break the strong nitrogen-nitrogen triple bond of the abundant N2 in our atmosphere requires a lot of carbon-polluting energy and methane. Finally, one side effect of Haber Bosh was the efficient production of high explosives which the inventors deployed on the battlefields of World War One.

So it’s gratifying to see some real progress being made to clean up Haber Bosh. In this case, the big idea is to clean up the industrial chemistry. There are a lot of other potential approaches that folks are looking at–one of my favorites is the idea that our staple crops might secure a ‘deal’ with the microbes in the soil that can fix nitrogen: fertilizer in return for nourishment in the form of biochemical products that only a plant can make. We have an existence proof of this approach: legumes do this. And we know that, in the case of corn, there exists at least one distant non-domesticated ancestor that seems to have had this sort of win-win proposition in place.