Variability between species in K/Ca ratios of successional plants

Summary The K/Ca ratios of six dominant perennial herbs on two abandoned agricultural fields in souther Ontario, Canada, were determined for June and September. Differential uptake of potassium and calcium conformed to root cation exchange theory, suggesting at least one possible mechanism influencing interspecific variability in mineral element composition of successional plants. K/Ca ratios were generally lowest for the legume, highest for the three gramineous species, and intermediate for the two dicotyledonous forbs.