Optimizing crop rotations is one of the proposed sustainable management strategies for increasing carbon sequestration. The main aim of this study was to evaluate the DeNitrificationDeComposition (DNDC) model for estimating soil parameters (temperature, moisture and exchangeable NO3− and NH4+), crop yield and nitrous oxide (N2 O) emissions for long-term multi-cropping systems in Hebei, China. The model was validated using five years of data of soil parameters, crop yields and N2 O emissions. The DNDC model effectively simulated daily soil temperature, cumulative soil nitrogen and crop yields of all crops. It predicted the trends of observed daily N2 O emissions and their cumulative values well but overestimated the magnitude of some peaks. However, the model underestimated daily water filled pore space, especially in dry seasons, and had difficulties in correctly estimating daily exchangeable NO3− and NH4+. Both observed and simulated cumulative N2 O results showed that optimized and alternative cropping systems used less nitrogen fertiliser, increased grain yield and decreased N2 O emissions compared to the conventional cropping system. Our study shows that although the DNDC model (v. 9.5) is not perfect in estimating daily N2 O emissions for these long-term multi-cropping systems, it could still be an effective tool for predicting cumulative emissions.
Funding: National Natural Science Foundation of China (41830751), Hainan University Startup Fund (KYQD(ZR)-20098), the N Circle–a BBSRC-Newton Funded project (BB/N013484/1) and EU Horizon 2020 Programme (Super-G).
We thank Bing Gao for providing measurement datasets and Xinping Chen for managing the field trial.
- Crop productivity
- DNDC model
- Multi-cropping cropping system
- Nitrous oxide
- Soil parameters