Variability of ammonium and nitrate in disturbed and undisturbed forest soils

Non-Peer ReviewedThe spatial distribution of NH4+- and N03--N in forest soils, as affected by site disturbance, was studied at the landscape-scale. A sampling grid, consisting of 169 points, was established at an undisturbed site located in Prince Albert National Park. Additional grids, consisting of 36 and 49 sampling points, were established at a burned and a clear-cut site, respectively. Similar levels of inorganic-N at the undisturbed and disturbed sites suggests that management practices had little effect on the availability of inorganic-N. Similarly, the spatial distribution of inorganic-N was not related to landform element complexes, suggesting that hydrologic processes were not the primary factor controlling the distribution of inorganic-N at the scale studied. The occurrence of NH4+ -N as the dominant inorganic-N form suggests that nitrification was strictly limited in these forest soils. This contrasts agricultural soils in which nitrification often proceeds swiftly in the presence of NH4+-N