Nitrogen in ectomycorrhizal mat and non-mat soils of different-age Douglas-fir forests
1993
Aguilera, L.M. | Griffiths, R.P. | Caldwell, B.A.
In an attempt to determine how stand age and mat-forming fungi affect N chemistry in forest soils, soils with or without ectomycorrhizal mats were collected from five Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] forest stands, age 2-450 yr, in the Oregon Cascade Mountains. A number of chemical and biological variables were measured in these soils, including; soil organic matter (SOM), pH, total N, inorganic N, extractable NH4+ and NO3(-), fungal hyphal length, numbers of bacteria, and labile C and N. Total soil N and labile N both were significantly greater in old-growth soils than in other soils, suggesting that forest soils become enriched in organic N with age. Labile C concentrations were higher in mat than in non-mat soils of all age classes but were significantly higher only in the older stands. This finding suggests that ectomycorrhizal mat communities affect soil N with age both by selectively removing organic N and by producing compounds with high C:N ratios.
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