ABSTRACT
Soil N accumulation during succession has been reviewed by Stevens and Walker (1970), Major (1974), and Jenny (1980). In harsh environments (Le., deserts and tundra) and during the earliest stages of soil development, it is the activity of primary colonizing microorganisms that imports N and provides for its accumulation. Cyanobacteria are particularly important in this regard (Fogg et al., 1973). As soil development proceeds and conditions become increasingly conducive to secondary succession, NZ-fixing plant species become established and characteristically dominate (Fogg et al., 1973; Burns and Hardy, 1975; Granhall, 1981).
