Effects of Elevated Air Temperature and CO₂ on Maize Production and Water Use Efficiency under Future Climate Change Scenarios in Shaanxi Province, China

• Main Authors: Qaisar Saddique, Muhammad Imran Khan, Muhammad Habib ur Rahman, Xu Jiatun, Muhammad Waseem, Thomas Gaiser, Muhammad Mohsin Waqas, Ijaz Ahmad, Li Chong, Huanjie Cai
• Format: Article
• Language: English
• Published: MDPI AG 2020-08-01
• Series: Atmosphere
• Subjects: CERES-Maize; temperature; climate change; ET; maize yield; WUE
• Online Access: https://www.mdpi.com/2073-4433/11/8/843

The ongoing global warming and changing patterns of precipitation have significant implications for crop yields. Process-based models are the most commonly used method to assess the impacts of projected climate changes on crop yields. In this study, the crop-environment resource synthesis (CERES)-Maize 4.6.7 model was used to project the maize crop yield in the Shaanxi Province of China over future periods. In this context, the downscaled ensemble projections of 17 general circulation models (GCMs) under four representative concentration pathways (RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5) were used as input for the calibrated CERES-Maize model. Results showed a negative correlation between temperature and maize yield in the study area. It is expected that each 1.0 °C rise in seasonal temperature will cause up to a 9% decrease in the yield. However, the influence of CO₂ fertilization showed a positive response, as witnessed by the increase in the crop yield. With CO₂ fertilization, the average increase in the maize crop yield compared to without CO₂ fertilization per three decades was 10.5%, 11.6%, TA7.8%, and 6.5% under the RCP2.6, RCP4.5, RCP6.0, and RCP8.5 scenarios, respectively. An elevated CO₂ concentration showed a pronounced positive impact on the rain-fed maize yield compared to the irrigated maize yield. The average water use efficiency (WUE) was better at elevated CO₂ concentrations and improved by 7–21% relative to the without CO₂ fertilization of the WUE. Therefore, future climate changes with elevated CO₂ are expected to be favorable for maize yields in the Shaanxi Province of China, and farmers can expect further benefits in the future from growing maize.