The Science of Phosphorus

Nationwide, runoff from non-point sources is the largest source of nutrients, including N (nitrogen) and P (phosphorus) discharged to surface water. Although phosphorus is the 11th most abundant element in the earth’s crust, most natural phosphate compounds are very insoluble, and therefore, not quickly replenished. Therefore, plant available phosphorus is only a fraction of phosphorus in the soil. To make up for the difference between what is available and what is needed, more soluble forms are created for use in commercial fertilizers. Unfortunately, this same property makes them susceptible to runoff to surface waters through field tiles, storm sewers, and non-point sources. 

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