(1) Expeliments were conducted, with the object of findinig the control measures for the magnesium deficiency of grape trees in the sandy hill region.
The auther surveyed the chemcial composition of soils in this area and studied the effect of magnesium concentraion for the growth of young grape trees in sand culture using this sandy soil.
(2) The contents of organic matter and total N in the cultured soils were notably higher and exchangeable Ca, Mg and K also higher than in the non cultured soils. But the rate of Mg increase was about a half as low as Ca and K.
It means that it is important to apply compost in this soils but not sufficient for supplying available Mg, and therefore in addition to it, Mg must be fertilized as well as 3 ingredients and Ca.
(3) In sand culture, the Mg levels were changed such as 0, 20, 40, 80 and 160 ppm as MgO and the other elements were always provided in constant proportion.
For shoot growth 20, 40 and 80 ppm, especialy 80ppm of Mg nutrient were found to be favourable concentration. The treatment of "Mg non fertilizer" caused hevy Mg deaficiency and the shoot growth in 160 ppm plot was worst of all.
(4) The content of Mg in leaves varied with its concentration in the culture solution and apparent reciprocal relationships between Mg and K in leaves and Mg and Ca in shoots were observed. Leaf Mg content of non Mg fertilized plot was 0.06% on dry matter and at 20, 40 and 80 ppm whitch were favarable concentration for shoot growth, it was respectively 0.19, 0.21 and 0.27%.
(5) After growth season the auther surveved the exchangeable cations in the soil of each experimental pot and the same relationships between Ca, Mg and K as in leaves were found in the soils.