Measuring and modelling energy partitioning in canopies of varying complexity using MAESPA model

DynACof: A process-based model to study growth, yield and ecosystem services of coffee agroforestry systems

“…"Coffee-Flux" is a collaborative research observatory (https://www.umrecosols.fr/recherche/projets/53-coffee-flux) monitored continuously since 2009 and located on the Aquiares coffee farm. This research site has been intensively studied and described in detail, notably for hydrology and eddy-covariance by Gómez-Delgado et al (2011); LAI by Taugourdeau et al (2014); light budget by ; belowground biomass and NPP by Defrenet et al (2016), ecosystem biomass, NPP and LUE by Charbonnier et al (2017); and energy balance, water balance and surface temperature by Vezy et al (2018).…”

“…Perennial plantations are difficult to study, because their relatively long growing cycle extends the period necessary for data acquisition, and because the heterogeneity of the canopy sometimes significantly increases the intra-plot light and micro-meteorological anisotropy, such as for temperature, vapor pressure or aerodynamic conditions (Luedeling et al, 2014;Luedeling et al, 2016). Agroforestry systems (AFS) are probably the most complex perennial agroecosystems (Malézieux et al, 2009), because they have the most heterogeneous vertical and/or horizontal canopies, and these affect all ecosystem fluxes Vezy et al, 2018). Yet, AFS have the potential to enhance ecosystem services (Jose, 2009;Lin, 2010;Taugourdeau et al, 2014) such as carbon sequestration (Jose and Bardhan, 2012;Oelbermann et al, 2004), and to mitigate climate pressure on crops (Lin, 2007).…”

“… Two other models have also been applied to coffee in an agroforestry system using 3D light interception modules: in Dauzat et al (2001), where only a sample of a few coffee plants were simulated, and using the MAESPA model to simulate the whole system. Since MAESPA was recently demonstrated to accurately predict light distribution, canopy temperature and water and energy balance in such systems Charbonnier et al, 2017;Vezy et al, 2018), the model can readily compute all variables that are potentially influenced by the complex canopy structure. However, its relatively high computation time still limits its application for full rotations of coffee under AFS.…”

“…Consequently, we designed DynACof to incorporate a plant-scale reproductive phenology formalism inspired by Rodríguez et al (2011) but dependent on canopy temperature, with different sub-modules to adapt coffee and shade tree management, density and tree species, as in Van Oijen et al (2010b), and metamodels calibrated from MAESPA simulations for spatially-dependent variables, such as diffuse and direct light extinction coefficients, light use efficiency, leaf water potential, transpiration, and sensible fluxes (Vezy et al, 2018).…”

“…Van Oijen et al (2010b), andlater Rahn et al (2018), who further developed the CAF2007 model, proposed a Bayesian calibration based on an extensive screening of the literature and a sensitivity analysis, but no model evaluation against field data at this stage. Alternatively, we propose a multipleobjective strategy of evaluation in this study, relying on a large range of state and flux variables measured at the same time by the end of the crop rotation, including eddy-covariance fluxes, coffee and shade tree biomass measured at organ scale, necromass, yield, NPP, water balance and energy balance, and finally farm registers to describe management during a complete rotation Charbonnier et al, 2017;Defrenet et al, 2016;Gómez-Delgado et al, 2011;Taugourdeau et al, 2014;Vezy et al, 2018).…”