The purpose of the experiments, described in this paper is to examine the effect of calcium on the fixation of applied potash in clay minerals, namely, kaolinite, sericite and montmorillonite.
The results were as follows :
1) The amount of fixed potash reduced in both conditions, namely, submerged condition and alternately dried and wetted condition.
2) As a general tendency, it was noted that the amount of fixed potash reduced, according to the increase of water soluble potash and the reduction of exchangeable potash.
3) When calcium hydroide was applied to sericite the amount of fixed potash increased with the increase of water soluble and exchangeable potash, in alternately dried and wetted condition.