Nitrogen: the chemical fertilizer connection

I’ve been thinking a lot about nitrogen lately. It plays a crucial role in the biosphere because all of the peptide bonds that make up proteins contain that element. And proteins are truly ubiquitous in living things from the very smallest bacteria up to giant redwoods. Because plants require nitrogen to grow, farmers must buy nitrogen containing chemical fertilizers to feed their crops. The run off from their fields pollutes by overloading our waters with nitrogen in the chemical form (called ‘fixed’) found in their fertilizers. The result of that artificial fertilization of lakes and streams (and even coastal estuaries) are algal blooms that crowd out the rest of the biosphere for resources. It’s not good.

Not all crops require fertilizer though. Some crops—legumes—have made a peace pact with the soil microbiome surrounding their roots. In the deal, the local microbes do the work of the farmer by fixing atmospheric nitrogen into the form that plants can use. In return the plants provide other nutrients to the bugs. One of the great challenges for the future of food is to figure out a way to make that peace pact work for our major commercial feed crops like wheat or corn. And that’s not only because it would be a good thing for our waterways. It turns out that chemical fertilizer is also very expensive and requires natural gas to synthesize urea. So if we figured out a way to replicate the microbial pact that legumes have, we could not only reduce pollution, we could save a whole lot of money.