Modeling N2O emissions of complex cropland management in Western Europe using DayCent: Performance and scope for improvement

• DOI: 10.1016/j.eja.2022.126613
• Publication Date: 2022-09-02T09:22:38Z
• Authors: Marcio dos Reis M...; Magdalena Necpalova; Christof Ammann; Nina Buchmann; Pierluigi Calanca; Christophe R. Fle...; Melannie D. Hartman; Maike Krauss; Philippe Le Roy; Paul Mäder; Regine Maier; Thierry Morvan; Bernard Nicolardot; Colin Skinner; Johan Six; Sonja G. Keel
• Keywords: Scope (computer science)

Under the United Nations Framework Convention on Climate Change (UNFCCC), industrialized countries and with economies in transition (so called Annex 1 countries) are encouraged to move towards more sophisticated approaches for national greenhouse gas reporting. To develop a model-based approach estimating nitrous oxide (N2O) emissions from agricultural soils, model calibration is one of first important steps. Extensive multisite field observations necessary this purpose, as management Western Europe complex (e.g., diverse crop rotations, different types fertilizer soil tillage). In present study, we used ca. 24,000 daily N2O flux six cropland sites, two France four Switzerland, conduct an automatic data-driven biogeochemical DayCent. This planned be reporting entire European Union well Switzerland. After site-specific calibration, leave-one-out (LOO) cross-evaluation was conducted assess model’s ability predict sites it not calibrated for. Mean observed fluxes 54 interactions cycles, studies treatments were evaluate model. The LOO resulted R2 0.63 prediction mean per cycle, compared 0.51 obtained default parameterization. Our results showed that improvement predictions associated adjustment only seven parameters controlling N cycle maximum nitrification amount inflection point effect water-filled pore space denitrification) out several hundred parameters. These wide range values between revealing challenge calibration-based simulations. Despite remaining uncertainty, our estimates emission (2.64 kg ha-1) clearly closer measurements (2.67 than commonly factor (1.60–1.71 ha-1). Based extensive observations, suggest that, after few parameters, DayCent simulations useful management. based-estimates accurate, because they consider key drivers disregarded by simpler approaches. Moving methods reporting, therefore expected improve accuracy additionally allows mitigation options.