Water, Air, and Soil Pollution

, Volume 177, Issue 1, pp 335–347

Vegetation Type Affects the Relationship Between Soil Carbon to Nitrogen Ratio and Nitrogen Leaching

  • E. C. Rowe
  • C. D. Evans
  • B. A. Emmett
  • B. Reynolds
  • R. C. Helliwell
  • M. C. Coull
  • C. J. Curtis
Article

DOI: 10.1007/s11270-006-9177-z

Cite this article as:
Rowe, E.C., Evans, C.D., Emmett, B.A. et al. Water Air Soil Pollut (2006) 177: 335. doi:10.1007/s11270-006-9177-z

Abstract

Nitrate leaching occurs when the soil's nitrogen immobilisation and plant uptake capacity has been saturated. Several widely-used models of nitrogen saturation incorporate a breakthrough function in which N begins to be leached at C/N values below an upper threshold, and is completely leached at C/N values below a lower threshold. In a survey of deciduous and coniferous woodland, acid grassland and heathland sites for which both C/N and nitrate flux measurements were available, deciduous woodland and acid grassland typically had lower C/N ratios, and began leaching nitrate at a lower C/N ratio, than coniferous woodland and heathland. Least-square fits of nitrate breakthrough functions gave upper thresholds (no nitrate leaching) of 27 mol C mol−1 N for deciduous woodland and acid grassland and 50 mol C mol−1 N for coniferous woodland and heathland. Upper thresholds were similar, at 24 and 51 mol C mol−1 N, respectively, for total inorganic N (NH4 + NO3) leaching flux as a proportion of total inorganic N influx. In conifer plantations, stand maturity had a large effect, suggesting that a breakthrough function is unsuitable for modelling systems that are in disequilibrium. However, there was sufficient evidence to suggest that using different breakthrough C/N thresholds for different groups of vegetation would improve predictions of N saturation and leaching at both plot and catchment scales. The difference may be related to the reactivity of soil carbon; soils with a large proportion of recalcitrant carbon are likely to begin leaching nitrate at a higher C/N value than soils with more labile carbon.

Keywords

deposition eutrophication forestry grassland heathland pollution retention 

Copyright information

© Springer Science + Business Media, Inc. 2006

Authors and Affiliations

  • E. C. Rowe
    • 1
  • C. D. Evans
    • 1
  • B. A. Emmett
    • 1
  • B. Reynolds
    • 1
  • R. C. Helliwell
    • 2
  • M. C. Coull
    • 2
  • C. J. Curtis
    • 3
  1. 1.Centre for Ecology and HydrologyOrton BuildingBangorU.K.
  2. 2.Macaulay InstituteAberdeenU.K.
  3. 3.Environmental Change Research CentreUniversity College LondonLondonU.K.

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