Potassium Supply Rate as Measured by Exchange Membranes in a Calcareous Sand
2006
Woods, Micah S. | Rossi, Frank S. | Ketterings, Quirine M.
Cation exchange membranes [Plant Root Simulator (PRS) probes] were used to evaluate the K supply rate of a calcareous sand putting green. Creeping bentgrass [Agrostis stolonifera var. palustris (Huds.) Farw.] leaf K content was used as an indicator of K bioavailability. On all 14 measurement dates in 2002 and 2003, the K supply rate increased in experimental plots to which K fertilizer had been applied. On 9 of the 12 dates when leaf samples were collected, K content in leaf samples increased with K supply rate. We conclude that K supply rate is a meaningful indicator of K bioavailability, and exchange membranes offer potential for assessment of in situ variability in K supply. However, the sensitivity of the exchange membranes to changes in soil K supply over time presents obstacles to simple interpretation of supply rate measurements.
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