Simulating N2O emissions following crop residue return while preserving consistency at the crop succession scale: A multi-year field assessment of the STICS model

Abstract

Effective mitigation of agricultural greenhouse gas emissions requires improved prediction of how management practices affect soil nitrous oxide (N 2 O) emissions. This study aimed to evaluate the ability of the STICS model to simulate the response of the N2O emissions to crop-residue return events, while preserving the model performance at the crop-succession scale. Data from eight arable systems in a long-term experiment, which generated variations in the amount and composition of residues returned to soil, were used to calibrate the denitrification module of STICS and to evaluate performance on an independent dataset. Two model versions were compared: the standard one and a modified version accounting for the effect of soluble compounds released during residue decomposition on denitrification potential. Model performance was assessed both at the scale of crop successions and over 60-day periods following residue return. STICS simulated 10-year cumulative N 2 O emissions accurately for most systems. However, simulation of emissions linked to residue management remained inconstant, even after calibration focused on post-return periods. The modified version of the STICS model yet produced responses to residue incorporation consistent with those reported in the literature and improved simulation of certain residue return events. Its limited influence on improving performance at the crop succession scale or across all return events confirms the observed rather low sensitivity of N 2 O emissions to residue management at this site, which is likely to be due to inherent soil or residue properties.