Modelling methane emissions and grain yields for a double-rice system in Southern China with DAYCENT and DNDC models

Yang Guo; Guangbin Zhang; Mohamed Abdalla; Matthias Kuhnert; Haijun Bao; Hua Xu; Jing Ma; Khadiza Begum; Pete Smith

doi:10.1016/j.geoderma.2023.116364

Modelling methane emissions and grain yields for a double-rice system in Southern China with DAYCENT and DNDC models

Geoderma. 2023 Mar:431:116364. doi: 10.1016/j.geoderma.2023.116364.

Authors

Yang Guo^{1

2}, Guangbin Zhang³, Mohamed Abdalla², Matthias Kuhnert², Haijun Bao¹, Hua Xu³, Jing Ma³, Khadiza Begum⁴, Pete Smith²

Affiliations

¹ School of Spatial Planning and Design, Zhejiang University City College, Hangzhou 310015, China.
² School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK.
³ State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
⁴ Geotree Environmental Monitoring, London SW1E 5JL, UK.

Abstract

Methane (CH₄) is an important greenhouse gas that contributes to climate change and one of its major sources is rice cultivation. The main aim of this paper was to compare two well-established biogeochemical models, namely Daily Century (DAYCENT) and DeNitrification-DeComposition (DNDC) for estimating CH₄ emissions and grain yields for a double-rice cropping system with tillage practice and/or stubble incorporation in the winter fallow season in Southern China. Both models were calibrated and validated using field measured data from November 2008 to November 2014. The calibrated models performed effectively in estimating the daily CH₄ emission pattern (correlation coefficient, r = 0.58-0.63, p < 0.001), but model efficiency (EF) values were higher in stubble incorporation treatments, with and without winter tillage (treatments S and WS) (EF = 0.22-0.28) than that in winter tillage without stubble incorporation treatment (W) (EF = -0.06-0.08). We recommend that algorithms for the impacts of tillage practice on CH₄ emission should be improved for both models. DAYCENT and DNDC also estimated rice yields for all treatments without a significant bias. Our results showed that tillage practice in the winter fallow season (treatments WS and W) significantly decreased annual CH₄ emissions, by 13-37 % (p < 0.05) for measured values, 15-20 % (p < 0.05) for DAYCENT-simulated values, and 12-32 % (p < 0.05) for DNDC-simulated values, respectively, compared to no-till practice (treatments S), but had no significant impact on grain yields.

Keywords: China; DAYCENT model; DNDC model; Double-rice cropping system; Management practices; Methane.