FOLIAR POTASSIUM, CALCIUM, MAGNESIUM, ZINC, AND MANGANESE CONTENT IN SOYBEAN CULTIVARS AT DIFFERENT STAGES OF DEVELOPMENT

Plant tissue accumulation of potassium (K), calcium (Ca), magnesium (M g), zinc (Zn), and manganese (Mn) was determined for six soybean [Glyc ine max (L.) Merr.] cultivars at successive stages of development. No nutrient accumulation patterns among the cultivars were found. The res ults obtained showed that the highest concentrations of K were found a t the vegetative stage (V) and the lowest towards the end of the life cycle of the plant (R55). By contrast, Ca was lowest at the vegetative stage while increasing in the leaves in later growth stages. No signi ficant differences in Mg content were found between growth stages. Man ganese levels were lower at R2 and R4 than at R55 stages of growth wit h an accumulation rewards the end of the reproductive cycle. Changes i n Zn content between stages were different for each cultivar. The duri ng behavior of these elements is related to the difference in their mo bility and transport capacities within the plant.