Contribution of different grass species to plant-atmosphere ammonia exchange in intensively managed grassland
Mattsson, M.; Herrmann, B.; Jones, S.; Neftel, A.; Sutton, M. A.; Schjoerring, J. K.. 2008 Contribution of different grass species to plant-atmosphere ammonia exchange in intensively managed grassland. Biogeosciences Discussions, 5. 2583-2605.Full text not available from this repository.
Species diversity in grasslands usually declines with increasing input of nitrogen from fertilizers or atmospheric nitrogen deposition. Conversely, species diversity may also impact the build-up of soil nitrogen pools. Limited information is available on how plant-atmosphere ammonia exchange is related to species diversity in grasslands. We have here investigated grass species abundance and different foliar nitrogen pools in 4-year-old intensively managed grassland. Apoplastic pH and NH4+ concentrations of the 8 most abundant species were used to calculate stomatal NH3 compensation points. Apoplastic NH4+ concentrations differed considerably among the species, ranging from 13 to 117 μM, with highest values in Festuca pratensis. Also apoplastic pH values varied, from pH 6.0 in Phleum pratense to 6.9 in Dactylis glomerata. The observed differences in apoplastic NH4+ and pH resulted in a large span of predicted values for the stomatal NH3 compensation point which ranged from 0.20 to 6.57 nmol mol−1. Three species (Lolium perenne, Festuca pratensis and Dactylis glomerata) had sufficiently high NH3 compensation points and abundance to contribute to the NH3 emission of the whole field. At the same time, other grass species such as Phleum pratense and Lolium multiflorum had NH3 compensation points below the atmospheric NH3 concentration and could thus contribute to NH3 uptake from the atmosphere. Evaluated across species, leaf bulk-tissue NH4+ concentrations correlated well (r2=0.902) with stomatal NH3 compensation points calculated on the basis of the apoplastic bioassay. This suggests that leaf tissue NH4+ concentrations combined with data for the frequency distribution of the corresponding species can be used for predicting the NH3 exchange potential of a mixed grass sward.
|Programmes:||CEH Programmes pre-2009 publications > Biogeochemistry > BG01 Measuring and modelling trace gas, aerosol and carbon > BG01.1 UK nitrogen and sulphur compounds
CEH Programmes pre-2009 publications > Biogeochemistry > BG02 Recovery from acidification and eutrophication
|Additional Information:||Biogeosciences Discussions is an Open Access Journal|
|NORA Subject Terms:||Atmospheric Sciences|
|Date made live:||18 Feb 2009 13:15|
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