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Potassium supply rate as measured by exchange membranes in a calcareous sand

Woods, M.S., F.S. Rossi and Q.M. Ketterings. 2006. Applied Turfgrass Science doi:10.1094/ATS-2006-0323-01-RS


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.

Key Words

fertilization, potassium, putting green, supply rate, turf grass