植生上カリとアルカリ土類との対抗作用に就て

抄録

The authors had published a paper concerning antagonistic effects of iron salts on the availability of potash fertilizers. (8) It was known that the soluble potash salts vary their nutritive effect for rice plants by mixing soluble iron salts whose anion is the same kind to the potash salts. Variation of the effect had been attributed to the antagonistic action between cations of these salts. Compounds as well as iron salts are considered to display the antagonism to potash under the similar condition. An investigation, hereupon, using soluble salts of lime and magnesia instead of iron salt, has been carried out in order to determine their antagonistic influence on the effect of soluble potash salts for rice plants. 0.05 N K_2SO_4,0.1 N KCI and 0.01 N-0.05 N KNO_3 solutions were taken as the potash nutrients. Corresponding salt solution of CaO or MgO on the basis of the same anion but in various normalities was added into every kind of the potash solution. The rice plants were sown and grown for 18 days in quartz sand after the Neubauer's method, applying the mixed salt solution with no other nutrient. It is shown in the results that : (1) K : Ca and K : Mg antagonisms are noticeable at the growth of rice plants. (2) Strength of the antagonistic action obviously depends on kind of cations and anions, being in relations of Ca>Mg by the cations and SO_4>CI>NO_3 from viewpoint of the anions combined with these cations. (3) The antagonistic action always shows the largest effect under such condition as dissociation degree of both salts in a solution is equal. (4) The antagonism reveals unfavorable effect when the nutritive potash is present in less than adequate amount, while it displays the contrary effect, reducing the undesirable action of the potash when this element excessively occurs in the medium. (5) The nitrates, however, hardly display the antagonism between cations, since they change the dissociation degree to no appreciable extent by mixing in a solution (From Laboratory of Soils and Fertilizers, Taihoku Imperial University, Taiwan, Japan.)