Soil P Removal by Crop Harvest

Excessive STP can be reduced when P removal in crop harvest exceeds P application.  While typical P concentration in plant material varies somewhat by crop species, and even by variety, the concentration of P in plant tissue generally does not differ greatly from 0.3%.  Therefore, the rate of P removal is most affected by the amount of biomass removed.  More biomass harvested means more P removed from the soil. Whole plant removal, as with silage harvest, needs to be balanced with the risk of increased erosion, as the erosion rate often is a greater determinant of runoff P loss than is surface soil STP.