Multi-model ensembles for assessing the impact of future climate change on rainfed wheat productivity under various cultivars and nitrogen levels

Abstract

Wheat production in rainfed cropping systems is highly vulnerable to climate change, particularly in developing countries. Therefore, assessing the climate change impacts on rainfed wheat production is needed for ensuring global food security. Nitrogen (N) application has been reported to mitigate the impact of climate change on crop production, but its impact in rainfed cropping systems remains uncertain and/or rarely explored. Crop models have been commonly used for projecting the impacts of climate change on crop production. However, uncertainties from single-model simulation analyses call for multi-model simulation capabilities. Here, three models (APSIM-Wheat, CERES-Wheat, and Nwheat) were calibrated and evaluated for simulating phenology, agronomic traits, rainwater use efficiency (RWUE), and N use efficiencies under rainfed conditions in Pakistan. Five Global Circulation Models examined from 2041 to 2070 (RCP8.5) indicated an increase in mean growing temperature and changes in growing season rainfall between 1.6 and 4.9 ℃ and − 34 and + 39 %, respectively. Therefore, cool and dry, cool and wet, middle, hot and dry, and hot and wet projections were selected. All crop models successfully simulated the investigated parameters for different wheat cultivars and N application rates. APSIM-Wheat showed the best performance for validating the RWUE, plant N uptake, N utilization efficiency, and N uptake efficiency (NRMSE = 11.2–14.5 %), while CERES-Wheat performed well for grain yield and N use efficiency (NRMSE = 5.1–6.1 %). Nwheat showed a minimum average NRMSE for plant dry mass and harvest index (3.8–7.8%). All crop models predicted the maximum reduction in grain yield under hot and dry conditions. Compared to baseline, future climate change caused minimum and maximum grain yield reductions for Faisalabad-2008 (6 %) and AUR-809 (11 %), respectively, whereas, for N application rates, the minimum and maximum grain yield reductions were observed for N0 (7 %), and N140 (10 %), respectively. There were no significant differences in grain yield and RUWE across N application rates under future climate change. However, applying N from N0 to N70 significantly increases grain yield (82 %) and RWUE (77 %) across cultivars under future climate change. The findings would have valuable implications in tackling the negative impacts of future climate change on wheat production through the selection of suitable cultivars and formulating crop N management strategies for rainfed areas.