There are many apparent advantages of using PRS™-probes to study soil nutrient dynamics in situ; however, they are NOT the only way of looking at soil nutrients. As with any analytical tool, the PRS™-probes have certain limitations that need consideration when developing experiments. These limitations, which are addressed elsewhere, include: finite burial length; susceptibility to losing adequate contact between the ion-exchange membrane and soil when placed in heavy soils undergoing prolonged drought conditions; predation and breakage by birds, insects, termites, cattle, bears, etc.; deep placement inconvenient (i.e., need to dig a soil pit down to desired depth); and, prone to breakage in rocky soils. Despite these limitations, with careful consideration and the appropriate measures taken, the PRS™-probes will still yield accurate and precise data with which to base inferences, while minimizing PRS™-probe mortality.

Another consideration is that nutrient supply rates cannot be multiplied by two to provide an estimate of nutrient availability on a volume basis (i.e., kg ha^-1 for 15 cm depth). Also, plant roots are stronger ion sinks than an ion-exchange membrane; therefore, if the PRS™-probes are buried among roots for extended periods, the effects of competing sinks need consideration. Depending on the research objective this may not be a limitation; however, if a root grows against the ion-exchange membrane, adsorbed ions may be stripped off. It is also important to consider that PRS™-probes measure the bio-available pool but not the total nutrient pool. Then PRS™-probes measure nutrient bioavailability from the soil as opposed to total composition of the soil.