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Dise, N; Matzner, E; Forsius, M: Evaluation of organic horizon C:N ratio as an indicator of nitrate leaching in conifer forests across Europe, Environmental Pollution, 102, S1, 453-456 (1998) | |
Abstract: We evaluate the relationship between the carbon-to-nitrogen ratio (C:N) of the soil organic horizon and nitrate leaching in runoff or
seepage water from 33 conifer forests across Europe. The sites span a geographical range covering 11 countries from Ireland to
western Russia and Finland to the southern Alps, and encompass a wide range in throughfall nitrogen deposition. The aim of the
study is to evaluate the hypothesis that the C:N ratio of the organic (OH) horizon can be used to estimate the level of leaching of
nitrate from a forest ecosystem. The analysis suggests that C:N ratio can be an indicator of nitrate leaching for conifer forests across
Europe if these ecosystems are grouped into broad categories of throughfall nitrogen deposition. At low levels of N deposition (< 10
kg N ha-’ year-‘), nitrate leaching is low regardless of the OH C:N ratio. At intermediate (10-20 kg N ha-’ year-‘) and high (~20 kg N
ha-’ year-‘) N deposition, nitrate leaching increases with decreasing C:N ratio. In addition, for any given value of C:N, the level of
nitrate leaching is higher at high N-deposition sites than at intermediate N-deposition sites. From the current data, OH horizon C:N
ratio can give a reasonable estimate of the annual export flux of nitrate (95% confidence interval ca +5 kg N ha-’ year-‘) for sites
receiving throughfall-N up to about 30 kg N ha-’ year-‘. Above this level, the variability in the data increases, suggesting other factors
may need consideration to refine estimates of nitrate leaching.
Keywords: Atmospheric deposition; C:N ratio; forest ecosystems; nitrogen cycling; nitrate leaching; nitrogen deposition |
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