Use of the Rb/K Ratio to Evaluate Potassium Nutrition of Peatlands

Abstract

We determined the Rb/K ratio in two classes of forested peatlands, raised and perched bogs, in northern Minnesota, USA. These two classes of bogs are deficient in K, but differ somewhat in degree of deficiency and in source of K. We hoped to determine if the ratio differentiated between the two classes of bogs. 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 two classes. The ratio was apparently affected by biological selectivity in K uptake by plants under low-K conditions. These results raise questions concerning use of this ratio in ecosystem studies.