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Effects of elevated atmospheric CO2-concentration on fluxes of carbon and water vapour of a crop rotation
Project
Project code: vTI-BD-08-21
Contract period: 01.03.1998
- 01.12.2010
Purpose of research: Applied research
Besides global warming, the rapidly rising atmospheric CO2-concentration will directly affect vegetation. Elevated atmospheric CO2-concentration stimulates photosynthesis of most C3-plants and reduces leaf transpiration by causing stomatal closure. Several subsequent effects on biomass development and water relations (e.g. water use efficiency) of plant canopies are based on these primary reactions. The impact of CO2-concentration on photosynthesis depends on both endogenous (e.g. growth stage) and exogenous (climate) factors. Hence, CO2-effects on photosynthesis on the one hand and growth and yield on the other hand may vary substantially.In CO2-enrichment experiments, stomatal conductance for water vapour was observed to decline up to 50%. However, it is still unknown how this effects extrapolate to canopy level. Moreover, possible interactions and feedback reactions affecting canopy water fluxes within the canopy-atmosphere system need to be investigated.ithin the Braunschweig FACE-experiment (Free-Air-Carbondioxide-Enrichment), our project focuses on the effects of elevated atmospheric CO2-concentration (550 ppm) on canopy CO2/H2O-fluxes measured using a chamber system of a crop rotation (winter barley ? sugar beet ? winter wheat) under field conditions. The results are compared with data obtained using micrometeorological methods (eddy covariance) in order to extrapolate measured CO2-effects to field scale. Comparision with results gained from flux models are intended.
Section overview
Subjects
- Climate Change