From nurseries of Campbell Early grape planted and grown on acid soil with the application of different amount of various limes, the following results were obtained through the investigation on occurrence of magnesium deficiency symptom and the analysis of plant and soil for 5 years from 1964 to 1968.
1. Of calcium silicate, dolomite, agricultural lime, calcium hydrate used in this trial for the control of magnesium deficiency, the practical effect was obtained only with dolomite, and for the correction of soil pH, dolomite and calcium hydra to were equally effective, and agricultural lime was effective in about ⅓ while calcium silcate had the lowest effect.
2. The content of Mg in petiole, leaf blade, young leaf, fruit and the exchangeable Mg in soil were markedly higher at the plot of dolomite application than those at the other plots.
3. The content N, P, Ca, Fe, Mn, B in petiole and leaf blade showed no difference among the treatments while that of K in the plot of dolomite application showed lower trend in comparison with the other plots.
4. The coefficient of the occurrence of magnesium deficiency symptom to the Mg content in lea blade and in petiole was r=-0.753 and 0.665 respectively, and that of exchangeable Mg in soi to Mg content in petiole and in leaf blade was =0.824 and 0.745 respectively. Mg content in soil showed a trend of marked increase when exchangeable Mg in soil become above 2.0 me.
5. The optimum amount of dolomite application is estimated to be 360-500㎏ per 10a.
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