
Fig. 7. Denitrification limiting factors in the upper soil horizon (025 cm) of the topohydrosequence. Seasons and sites have been pooled together (means and standard errors, n = 36). ANA, denitrification activity of soil samples incubated with acetylene under N2 atmosphere alone. ANAC, denitrification activity of soil samples amended with carbon (4 g glucose kg-1 fresh soil) and incubated with acetylene under N2 atmosphere. ANAN, denitrification activity of soil samples amended with nitrate (10 mg NO3N kg-1 fresh soil) and incubated with acetylene under N2 atmosphere.