Synthetic nitrogen fertilizer became popular in the U.S. after World War II when large stocks of leftover ammonium nitrate munitions were marketed for agricultural use. However, the widespread adoption of synthetic fertilizer and associated agricultural practices had a host of unintended consequences to our environment, the quality of our foods, and the sustainability of our food system.
Synthetic fertilizers are banned from USDA’s organic production standards, but are used in conventional food production on a massive scale. More than 21 million tons of synthetic fertilizers were spread over American farmland in 2010 alone, covering about one-eighth of the continental land mass..
