Frequently Asked Questions

Topics: General / Technical / Logistical / Ordering / Past Research

How many PRS™-probes are required to complete a study?

As with any in situ research tool, the number of PRS™-probes required to accurately assess soil nutrient dynamics depends on: the size of your experimental unit; homogeneity of soils; the expected variability within treatments; and, the number of replications. If you are planning to measure cumulative nutrient supply rates throughout the growing season, then twice as many PRS™-probes are required, as freshly recharged PRS™-probes will need to be placed in each soil slot immediately upon removal of the current ones. A few extra PRS™-probes are sent with each order in case of accidental breakage during installation. These extra PRS™-probes also can be used as method blanks during analyses, but we will charge for analysis of method blanks as we would any other sample. It is best to decide at the beginning of your study the number of blanks you need for your project and include the number of blanks in your overall sample number. It is better to let us know how many samples are needed (Plots x Treatments x Sites = # Samples) rather than number of probes. An R&D coordinator will determine actual probes numbers after a discussion of the study site and objectives.

Note: a rule of thumb is to bury as many pair of PRS™-probes in each experimental unit as you would collect soil samples. The entire set of PRS™-probes then can be bulked together into one bag and eluted to create a single eluate sample for analysis, much like composite soil sample (see following figures for examples).