The profile distribution of the tier soil nonexchangeable potassium was characterized by following nonlinear equation:y=aebx(c+dcos2π(xe)/f).Premumarily toxonomic ciassmcation was carried out by use of the equation on which five profiles of tier soil was divided into three types. The part Tabled A in figure reflected changes of nonexchangeable potassium in the fimic cumulic epipeden or tieric process of the tier soil. The content of nonexchangeable potassium is high in cultivated orizon and lower with the increase of deepth in the soil profile

which is elated to the fimic cumulic process

plant uptake

potassium migration and eutrophlcation

and the other eco-environment factors. The results also indicated the synchronism and other space property between the exhaustion

accumulation of nonexchangeable pofassium and soil formation process with the participation of plants.