[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/03/EW-04-18-12-Fertilizer.mp3|titles=EW 04-18-12 Fertilizer]
Until the Industrial Revolution, we increased fertility in our farms and gardens by applying animal manure, compost, or minerals mined from the earth. Then, scientists developed a method to capture nitrogen for use in fertilizer. Synthetic fertilizer is responsible for the so-called Green Revolution that increased crop yields and supports the earth’s growing population.
Fertilizer supplies plants with key nutrients including nitrogen, phosphorus, and potassium as well as some micro-nutrients. Manufactured fertilizer is denser with these nutrients than many organic products, which is why it is so effective at increasing crop yields. Synthetic fertilizer is relatively inexpensive, and many farmers have adopted a “more is merrier” approach.
But about twenty-three percent of fertilizer applied to fields runs off into lakes, streams, and rivers. There, it upsets the natural chemical balance and has negative impacts on water quality and organisms. Dead zones in oceans, where fish and plants don’t thrive, are also attributed to fertilizer runoff.
Another problem is the large amount of natural gas that is required for the manufacture of fertilizer. Natural gas is a nonrenewable resource. As conventional sources become depleted, we must resort to methods like hydrofracking to obtain natural gas for fertilizer and other uses.
Other nonrenewable resources are used to manufacture fertilizer, including minerals that are mined, like phosphorus and potassium. These won’t last forever.
We could say that the world population of the twentieth century was brought to us by abundant food and artificial fertilizer. Whether we can keep manufacturing it through the twenty-first century is an open question.
Photo, taken on March 8, 2007 using a Konica Minolta DiMAGE S414, courtesy of Colin via Flickr.