火山灰土壌に於ける桃樹の早期落葉に関する研究(II)

抄録・要旨

(1) In the previous papers, the authers reported that early defoliation of peach trees on volcanic ash soil was caused by the deficiencies of Ca and Mg, especially that of Mg in the soil, and the early defoliation had injurious effects for shoot and root growth.(1957)
This study was carried out to know the cause of the early defoliation nlore exactly and to find the control measures for it.
(2) Results of sand culture expermient showed that the deficiency of Mg caused the early defoliation of peach trees and the deficiency of Ca was not the immediate cause of it. Therefore, when both Ca and Mg were deficient, the degree of defoliation was higher than that when Mg alone.
(3) It was difficult to control the symptoms by using the large amount of compost in the soil, but in addition to it, apply of lime and magnesuim sulfate was effective to decrease the early defoliation.