Modeling Carbon and Water Fluxes of Managed Grasslands: Comparing Flux Variability and Net Carbon Budgets between Grazed and Mowed Systems

A - Papers appearing in refereed journals

Puche, N., Senapati, N., Flechard, R., Klumpp, K., Kirschbaum, M. U. F. and Chabbi, A. 2019. Modeling Carbon and Water Fluxes of Managed Grasslands: Comparing Flux Variability and Net Carbon Budgets between Grazed and Mowed Systems. Agronomy. 9 (4), p. 183.

AuthorsPuche, N., Senapati, N., Flechard, R., Klumpp, K., Kirschbaum, M. U. F. and Chabbi, A.
Abstract

The CenW ecosystem model simulates carbon, water, and nitrogen cycles following ecophysiological processes and management practices on a daily basis. We tested and evaluated the model using five years eddy covariance measurements from two adjacent but differently managed grasslands in France. The data were used to independently parameterize CenW for the two grassland sites. Very good agreements, i.e., high model efficiencies and correlations, between observed and modeled fluxes were achieved. We showed that the CenW model captured day-to-day, seasonal, and interannual variability observed in measured CO2 and water fluxes. We also showed that following typical management practices (i.e., mowing and grazing), carbon gain was severely curtailed through a sharp and severe reduction in photosynthesizing biomass. We also identified large model/data discrepancies for carbon fluxes during grazing events caused by the noncapture by the eddy covariance system of large respiratory losses of C from dairy cows when they were present in the paddocks. The missing component of grazing animal respiration in the net carbon budget of the grazed grassland can be quantitatively important and can turn sites from being C sinks to being neutral or C sources. It means that extra care is needed in the processing of eddy covariance data from grazed pastures to correctly calculate their annual CO2 balances and carbon budgets.

KeywordsGrassland; Eddy covariance; Carbon cycling; Grazing; Mowing; CenW model
Year of Publication2019
JournalAgronomy
Journal citation9 (4), p. 183
Digital Object Identifier (DOI)doi:10.3390/agronomy9040183
Web address (URL)https://www.mdpi.com/2073-4395/9/4/183
Open accessPublished as ‘gold’ (paid) open access
Publisher's version
Output statusPublished
Publication dates
Online10 Apr 2019
Publication process dates
Accepted07 Apr 2019
Copyright licenseCC BY
PublisherMDPI
ISSN2073-4395

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