According to Peter Vitousek, a professor of biology at Stanford and a leading scholar on the nitrogen cycle, under optimum conditions and using best practices, plants take up only "50 or at best 60 percent" of the nitrogen laid on by farmers. So if so much of their fertilizer is going to waste, why do farmers apply so much? Vitousek explained that plants take up different amounts of nitrogen at different points in the growing cycle. To ensure that crops have sufficient N when they need it most, farmers essentially have to over-apply.
Globally, "about two-thirds of the nearly $100 billion of nitrogen fertilizer spread on fields each year is wasted," estimates The Economist. That's a lot of cash down the drain and a lot of nitrogen bleeding out of fields in various forms, wreaking all manner of havoc: Exhibit A, the 8,000-square-mile dead zone that blooms every year in the Gulf of Mexico, as Krysta Hozyash covered in this series.Fortunately, this is yet another environmental problem where the solution will save money: greater efficiency of Nitrogen fertilizer use will cut farmers' costs while improving the health of our soils, waterways and even the air we breathe.