Interactive effects of nitrogen deposition and fire on plant and soil chemistry in an alpine heathland
2008
Britton, A.J. | Helliwell, R.C. | Fisher, J.M. | Gibbs, S.
The response of alpine heathland vegetation and soil chemistry to N additions of 0, 10, 20 and 50 kg N ha−1 year−1 in combination with simulated accidental fire (+/−) was monitored over a 5-year period. N addition caused rapid and significant increases in plant tissue N content and N:P and N:K of Calluna vulgaris, suggesting increasing phosphorus and potassium limitation of growth. Soil C:N declined significantly with N addition, indicating N saturation and increasing likelihood of N leakage. Fire further decreased soil C:N and reduced potential for sequestration of additional N. This study shows that alpine heathlands, which occupy the headwaters of many rivers, have limited potential to retain deposited N and may rapidly become N saturated, leaking N into downstream communities and surface waters. N deposition on alpine heathland causes a rapid shift towards P limitation and subsequent N saturation of vegetation and soil.
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