The response of ecosystem carbon fluxes to LAI and environmental drivers in a maize crop grown in two contrasting seasons
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The eddy correlation technique was used to investigate the influence of biophysical variables and crop phenological phases on the behaviour of ecosystem carbon fluxes of a maize crop, in two contrasting growing seasons. In 2009, the reduced water supply during the early growing stage limited leaf area expansion, thus negatively affecting canopy photosynthesis. The variability of gross primary production (GPP) and ecosystem respiration (R eco) was mainly explained by seasonal variation of leaf area index (LAI). The seasonal variation of R eco was positively influenced by soil temperatures (T soil) in 2008 but not in 2009. In 2008, a contribution of both autotrophic and heterotrophic components to total R eco could be hypothesized, while during 2009, autotrophic respiration is supposed to be the most important component. Crop phenological phases affected the response of ecosystem fluxes to biophysical drivers.
KeywordsEcosystem carbon fluxes Environmental factors Leaf area index (LAI) Maize crop Vegetative phase Reproductive phase
This research was supported by the European Commission (Carboeurope IP project). Thanks are due to Dr. Lazzaro Iemma for his kind availability to host the work in his farm and Dr. Vincenzo Carbone for crop management and the useful assistance. The authors are thankful to Mrs Angela Balsamo and Mr Filippo Busiello (CNR-ISAFoM) for taking care of biometrical determinations.
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