Use of the Rb/K ratio to evaluate potassium nutrition of peatlands.

The Rb/K ratio was determined in 2 classes of forested peatlands, raised and perched bogs, in N Minnesota. These 2 classes are deficient in K, but differ somewhat in degree of deficiency and in source of K. The ratio was significantly lower in the living vascular vegetation on the raised bogs, but significantly higher in the deep peat in those bogs. There was no difference in the ratio in the living moss and shallow peat between bogs in the 2 classes. The ratio was apparently affected by biological selectivity in K uptake by plants under low-K conditions. Results raise questions concerning use of this ratio in ecosystem studies. -from Authors