Fertilizer effects of slag on fruit trees growing on volcanic-ash soil. II

Comparison of the growth of young apple trees as affected by slag and the separate applications of its main components

Abstract

1. Further experiment was conducted to clarify the reason of the growth promoting effect of slag applied to young apple trees on the volcanic-ash soil on which the author's previous paper reported.
2. When supplied separately with slag and its three main, components viz, lime, silica and magne-sia, the growth of one-year-old apple trees planted in the pots with volcanic-ash soil, was remarkably promoted, with a result that the trees given with slag or magnesia were much superior to those with lime or silica.
3. And, according to the leaf analysis for N, P, K, Ca, Mg and SiO₂, it was common that leaves of the trees fertilized with slag or magnesia con-tained more Mg than those with lime or silica, which appearently showed the magnesium deficiency. This fact might suggest that the effect of slag application exists in Mg element it contains.
4. However, considerable differences in the tree form were observed between the trees given with slag and with magnesia, that is, the former was inferior to the latter in the top-growth, while regard-ing the root-growth, the relation was reverse, thus top-root ratio (T/R) of the former being much lower than that of the latter.