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

Abstract

The DynACof model was designed to model coffee agroforestry systems and study the trade-offs to e.g. optimize the system facing climate changes. The model simulates net primary productivity (NPP), growth, yield, mortality, energy and water balance of coffee agroforestry systems according to shade tree species and management. Several plot-scale ecosystem services are simulated by the model, such as production, canopy cooling effect, or potential C sequestration. DynACof uses metamodels derived from a detailed 3D process-based model (MAESPA) to account for complex spatial effects, while running fast. It also includes a coffee flower bud and fruit cohort module to better distribute fruit carbon demand over the year, a key feature to obtain a realistic competition between sinks. We compared the model outputs with a highly comprehensive database on a coffee agroforestry farm in Costa Rica. The fluxes simulated by the model were close to the measurements over a 5-year period (RMSE= 1.60 gC m-2 d-1 for gross primary productivity; 0.63 mm d-1 for actual evapo-transpiration, 1.34 MJ m-2 d-1 for sensible heat flux and 1.88 MJ m-2 d-1 for net radiation), and DynACof satisfactorily simulated the yield, NPP, mortality and carbon stock for each coffee organ type over a 35-year rotation.

Modelling Agroforestry’s Contributions to People—A Review of Available Models

“…The source code of the DynACof model is unconditionally available in a public online repository [116]. The model code is licensed under the GNU Public License (GPL) and can therefore be obtained, changed and applied and published without further approval of the developer.…”

Assessing the accuracy and robustness of a process-based model for coffee agroforestry systems in Central America

“…It does constitute an important research question because alternate bearing is a phenomenon common to a large number of species of fruit trees (Monselise and Goldschmidt, 1982). In future model development, CAF2014 may benefit from incorporating the equations of Rodriguez et al (2011) for the dynamics of cohorts of reproductive organs and reserve compartment, as was done by Vezy et al (2020) in their DynACof model.…”

“…That would constitute a more mechanistic simulation of sink competition between leaf and reproductive compartments than we attempted here, but it would increase model complexity. Moreover, the method still needs independent testing across sites in multiple climatic zones (only one site was used by Vezy et al 2020) and Bayesian multi-site calibration following the approach that we developed here.…”

“…This model proved to be efficient at early stages of the coffee cycle (0-5 years old). Recently, Vezy et al (2020) incorporated the reproductive modules of Rodriguez et al (2011), including reproductive cohorts to best distribute the fruit carbon demand along the year and scaled them up to simulate ecosystem services (multi-objective calibration) of a whole agroforestry field for full rotations, but the model was parameterized and tested for only one site so far. Indeed, another model existed previously for the simulation of coffee production at the field scale in full sun and 6 agroforestry systems, CAF2007 (van Oijen et al, 2010b).…”

Paris Climate Agreement: Promoting Interdisciplinary Science and Stakeholders’ Approaches for Multi-Scale Implementation of Continental Carbon Sequestration

“…Diverse methods exist for upscaling local C-stock measurements and studies of C processes to larger areas. The methods include empirical ones (describing and explaining the variability of the locally measured quantity) and those based upon modelling of processes (e.g., simulating water and C fluxes at the scale of one entity within an agro-system [56]). Such approaches can be used conjointly, particularly for characterizing model uncertainties when upscaling.…”