Abstract
From the absorption of Ca and NH_4 ion by the soils in Ehime-ken, the following facts were obsorved. (1) The, amount of Ca absorbed by the noncolloidal fractions of the soils was, in every case, found to be almost equivalent to the amount of NH_4 absorbed. (2) On the contrary, the amount of Ca absorbed by the colloidal fraction was markedly greater than the amount of NH_4 absorbed, indicating that the colloidal fraction contains two different sorts, of H ion, one exchangeable and the other nonchangeable by NH_4 ion. (3) As is well-known "total exchange capacity" is often variable with the mothers used. This may be able to be partly explained from the facts above observed.
