Soil nutrients are intensively monitored in potato crops due to their high value and nutrient requirements and to frequent production on soils with low nutrient-holding capacity.   The potential use of Plant Root Simulator (PRS^TM) probes (ion exchange membranes in a plastic support) to monitor soil nutrients was evaluated in field trials conducted in Oregon and Manitoba in 2012.  A one-week burial period provided a more reliable indication of fertility treatment effects than a one-day burial period.  Soil supply rates of N, P and K were significantly affected by fertility treatment, date of burial and their interaction, depending on nutrient type and experiment.  A close relationship to petiole measurements was observed in some cases, but not others, which could be attributed to the differences in type of measurement.  Potential exists for use of PRS probes for in-season monitoring nutrients for potatoes.