Abstract
Soil pH, total carbon, total nitrogen and net nitrogen mineralization were measured in Japanese cedar (Cryptomeia japonica D. don) and Hinoki cypress (Chamaecyparis obtusa Endlicher) plantations on a precipitation gradient (1,690〜3,300mm) in Shikoku District. Net nitrogen mineralization rates by a laboratory incubation (25℃, 14-31days) showed substantial differences among forests ranging from 0.2 to 2.5mg N kg^<-1>d^<-1>. In high precipitation areas, soils had larger C/N ratio, lower nitrate pool and nitrogen mineralization rates than in low precipitation areas. This indicates that forest ecosystems in high precipitation areas have efficient nitrogen cycling with small nitrogen losses.
