Are We Running Out of Phosphorus?
Phosphorus is found naturally in the soil but only a small portion of it is readily available for plant uptake. Phosphorus needs to be in the form of phosphate to be utilized by plants. Most phosphorus fertilizer comes from mined phosphate rock. The phosphorus is then transformed to either phosphoric acid or elemental phosphorus before being turned into fertilizer (United States Environmental Protection Agency [EPA], 2012). Phosphate rock is used directly as a fertilizer in organic production; but otherwise, relatively little is used directly due to limited soluble P content, high transportation costs, and the slow release rate.