Impacts of climate change on drought risk of winter wheat in the North China Plain

Drought is a major natural disaster causing crop yield losses, while its occurrence mechanism and spatiotemporal variations in a changing climate are still not clear. Based on a long-term climatic dataset (during 1958–2015) from weather stations in the North China Plain (NCP), the influencing mechanism of various climatic factors on drought risk of winter wheat was quantified by using sensitivity analysis, Mann-Kendall trend test and slope estimation. The results indicated that climatic factors have changed considerably over the past six decades in the growth season of winter wheat. As a result, winter wheat suffered from severe droughts (with 350 mm of water deficit during its growth season), particularly at the jointing–heading and heading–mature stages, which were critical to crop yield formation. There were large spatial and temporal variations in drought risk and climatic change factors at different growth stages of winter wheat. Despite precipitation playing a vital role in determining the spatiotemporal patterns of drought risk, high temperature and low humidity along with other climatic factors at key growth stages of winter wheat aggravated drought risk. Particularly, temperature at nearly 90% weather stations showed a notablely upward trend, which exacerbated water deficit and drought risk of winter wheat. Given the complexity and high uncertainty of climate change, these findings provide important information for adapting crop production to future climate change and accompanied droughts while ensuring food security and agricultural sustainability.