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| Titel |
Have ozone effects on carbon sequestration been overestimated? A new biomass response function for wheat |
| VerfasserIn |
H. Pleijel, H. Danielsson, D. Simpson, G. Mills |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 16 ; Nr. 11, no. 16 (2014-08-27), S.4521-4528 |
| Datensatznummer |
250117564
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| Publikation (Nr.) |
 copernicus.org/bg-11-4521-2014.pdf |
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| Zusammenfassung |
| Elevated levels of tropospheric ozone can significantly impair the growth of
crops. The reduced removal of CO2 by plants leads to higher atmospheric
concentrations of CO2, enhancing radiative forcing. Ozone effects on
economic yield, e.g. the grain yield of wheat (Triticum aestivum
L.), are currently used to model effects on radiative forcing. However,
changes in grain yield do not necessarily reflect changes in total biomass.
Based on an analysis of 22 ozone exposure experiments with field-grown wheat,
we investigated whether the use of effects on grain yield as a proxy for
effects on biomass under- or overestimates effects on biomass. First, we
confirmed that effects on partitioning and biomass loss are both of
significant importance for wheat yield loss. Then we derived ozone dose
response functions for biomass loss and for harvest index (the proportion of
above-ground biomass converted to grain) based on 12 experiments and recently
developed ozone uptake modelling for wheat. Finally, we used a European-scale
chemical transport model (EMEP MSC-West) to assess the effect of ozone on
biomass (−9%) and grain yield (−14%) loss over Europe. Based on
yield data per grid square, we estimated above-ground biomass losses due to
ozone in 2000 in Europe, totalling 22.2 million tonnes. Incorrectly applying
the grain yield response function to model effects on biomass instead of the
biomass response function of this paper would have indicated total
above-ground biomass losses totalling 38.1 million (i.e. overestimating
effects by 15.9 million tonnes). A key conclusion from our study is that
future assessments of ozone-induced loss of agroecosystem carbon storage
should use response functions for biomass, such as that provided in this
paper, not grain yield, to avoid overestimation of the indirect radiative
forcing from ozone effects on crop biomass accumulation. |
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