PRS Technology


Nutrient supply rate is the net rate of nutrient ion adsorption by the PRS® Probe, expressed as the weight of nutrient adsorbed per surface area of ion-exchange membrane over time. The units used by Western Ag Innovations are μg nutrient/10 cm² ion-exchange membrane surface area/time of burial (i.e., 24 h, 2 wks, 4 wks, etc.). The convention of reporting nutrient supply rates in terms of 10 cm² is to facilitate working with data for diffusion-limited nutrients (i.e., P) having smaller fluxes. However, it is also acceptable to report the number per cm² membrane surface area instead of per 10 cm². The units also may be reported as μg ion/PRS® Probe/time of probe burial providing that the total surface area (17.5 cm²) of the ion-exchange membrane is mentioned somewhere within the document.

Important Note: it is invalid to divide the burial duration into smaller time units since adsorption of ions to the PRS® Probe is not linear over time.