You've heard of peak oil, but how about peak phosphorus?

Recent warnings from Arizona State University's "Sustainable Phosphorus Initiative Project" indicate that the essential plant nutrient phosphorus (P) may be overused in agriculture (causing environmental runoff and damage), while at the same time reserves are dwindling. As a result, they predict that unless steps are taken now to use P more sustainably, in the future P may become a limited and very expensive resource. In much the same way that we have begun to worry about "peak oil", agricultural economists…