Abstract
Both soy beans for summer and autumn were planted on the soil, deficient in magnesium. Of each plot applied with Mg-sulfate in increasing amount (see Table 1), leaves and stemes were sampled every two weeks. With these samples, magnesium was determined separately in three forms, water suluble, 95% alcohol soluble, and 0.5% HCl soluble. (see Table 1,2,3 and 4; Fig 1〜6) Refered to three periods of growing, flowering and podding, magnesium was seemed to be essential to produce pod. In general, Mg, sol. in H_2O, was most easily moved, while Mg, sol. in HCl, not so easily to be brought to be moved. When Mg, sol. in H_2O, decreased less than about 0.1% Mg, sol. in HCl, also began to decrease; The former magnesium contained 0.0〜0.5%, the latter became naught. Mg, sol in alc, decreased with the above decreases. Mg deficient symptom emerged, when Mg became 0.05〜0.1% in total. It was concluded that magnesium deficiency might occur when its amount sol. in H_2O, was reduced lees than 0.04%.
