1) Roots of the crop plant, either young or mature, whose requirement of lime are high, have higher concentrations of Ca, Mg and K throughout the control, additional Al and low pH plots. No such correlations are seen among those of SiO₂, Fe, Al and pH values. 2) In the roots of the crop plants, whose yields decrease on highly acidic volcanic ash soil, H-ion and Al contents readily increase under low pH and additional Al solution respectively, while, on the other hand, percentages of Ca, Mg and K are apt to decrease though not having less cation contents under the control conditions. 3) The conditons of containing Al and H-ions and those of containing Ca, Mg and K in the roots seem to be different. 4) These results obtained may due to the nature of protoplasms in the root. 5) On highly acidic volcanic ash soil, fewer exchangeable Ca and Mg, lower base saturation and higher Al-, H-ion concentrations are detrimental conditions to the plants of less tolerant to acidic soil.