Predicting maize yield response to climate change: Case Study in Cambodia

Climate change is a consequence of global warming which will alter temperature and rainfall patterns causing concern to crop yield production. As a poor agrarian country, Cambodia is highly vulnerable to the impacts of the climate variety. To enable making the effective resilience on mitigation and adaptation, the study on the impact of crop (maize) yield induced by climate change made by the combination between the crop model and climate Generator for agriculture use has been performed in this research. The climate parameters are generated by MarkSim DSSAT Weather File Generator where 3 Global Circulation Models (GCMs), GFDL-CM3, GISS-E2-H, and IPSL-CM5A-LR, among 17 GCMs with RCP 6.0 along with the horizontal periods from 2040 to 2060 inside the generator are selected. Plus, Aquacrop is a crop model used in the study and has been calibrated based on the sensitive parameters of crop under the environment at the experimental field at Cambodian Agricultural Research and Development Institute in 2016 as well as to simulate the crop characteristics inputting the projected climate in the future generated by above-climate method. The result shows the simulation of Aquacrop is well-performed since the simulated yield is 1.768 t/ha comparing to 1.806 t/ha of the observed. Furthermore, due to the statistical indicators, for EF, r, d, and NRMSE are 0.79, 0.94, 0.92, and 33.8%, respectively. However, the biomass and yield are predicted to decline relatively in between 2040 to 2060 for all the three GCMs with RCP 6.0. When climate parameters of GFDL-CM3 model has replaced into crop model, the yield will decrease significantly to around the mean value of 0.80 t/ha, while that of GISS-E2-H model will decline to the specific yield for around 1.27 t/ha, and IPSL-CM5A-LR will be 1.14 t/ha compared to 1.8 t/ha of the baseline result. Therefore, these affects from the climate change on crop yield should be the approach for mitigation, preparedness, and resilience strategies to the stakeholders of crop cultivation.