Incorporation of leaf nitrogen observations for biochemical and environmental modeling of photosynthesis and evapotranspiration
| Autor: | Bøgh, E., Birgitte Gjettermann, Per Abrahamsen, Søren Hansen, Jensen, N. H., Schelde, K., Søegaaard, H., Thomsen, A. |
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| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Zdroj: | Boegh, E, Gjetterman, B, Abrahamsen, P, Hansen, S, Jensen, N, Schelde, K, Soegaard, H & Thomsen, A 2007, ' Incorporation of leaf nitrogen observations for biochemical and environmental modeling of photosynthesis and evapotranspiration ', Eos Trans. AGU, Fall Meet. Suppl, vol. 88, no. 52, pp. B31B-0322 . < http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=table&application=fm07&convert=&converthl=&refinequery=&formintern=&formextern=&transquery=%28leaf%20nitrogen%29%20and%20sc%3dbiogeosciences&_lines=&multiple=0&descriptor=%2fdata%2fepubs%2fwais%2findexes%2ffm07%2ffm07%7c813%7c4216%7cIncorporation%20of%20leaf%20Nitrogen%20Observations%20for%20Biochemical%20and%20Environmental%20Modeling%20of%20Photosynthesis%20and%20Evapotranspiration%7cHTML%7clocalhost:0%7c%2fdata%2fepubs%2fwais%2findexes%2ffm07%2ffm07%7c7479476%207483692%20%2fdata2%2fepubs%2fwais%2fdata%2ffm07%2ffm07.txt > Bøgh, E, Gjettermann, B, Abrahamsen, P, Hansen, S, Jensen, N H, Schelde, K, Søegaaard, H & Thomsen, A 2007, ' Incorporation of leaf nitrogen observations for biochemical and environmental modeling of photosynthesis and evapotranspiration ', AGU Fall Meeting, San Fransisco, United States, 10/12/2007-14/12/2007 . University of Copenhagen |
| Popis: | impact on CO2 sequestration processes complicates the modeling of carbon cycle feedbacks to climate change. The use of remote sensing constitutes a valuable data source to quantify and investigate impacts of bulk leaf N contents, however information on the vertical leaf N distribution and its relation to photosynthetic (Rubisco) capacity should also be known to quantify leaf N impacts on canopy photosynthesis. In this study, impacts of the amount and vertical distribution of leaf N contents on canopy photosynthesis were investigated by combining field measurements and photosynthesis modelling. While most canopy photosynthesis models assume an exponential vertical profile of leaf N contents in the canopy, the field measurements showed that well-fertilized fields may have a uniform or exponential profile, and senescent canopies have reduced levels of N contents in upper leaves. The sensitivity of simulated canopy photosynthesis to the different (observed) N profiles was examined using a multi-layer sun/shade biochemically based photosynthesis model and found to be important; ie. for a well-fertilized barley field, the use of exponential instead of uniform vertical N profiles increased the annual assimilate by 12 percent. Perspectives for remote sensing based |
| Databáze: | OpenAIRE |
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