Fig. 2 Immediate quantity/intensity (Q/I) relations for K of the surface layers of selected pedons (a) Pedon 3 (b) Pedon 4 (c) Pedon 10 and (d) Pedon 13 representing the mountains, the upper footslopes, the lower footslopes and the alluvial terraces, respectively; K is a measure of labile K, and AR^K is the activity ratios (aK/(a _Ca+Mg)^1/2)