Spatiotemporal variations in summer maize droughts in the Huaibei Plain

PENG Yujie; ZHU Yonghua; LYU Haishen; LU Wen; ZHU Wanting; WANG Yining; WANG Zhenlong

doi:10.13522/j.cnki.ggps.2023507

Abstract：[Objective]Drought is a significant abiotic stress affecting agricultural production in many regions of China.This study investigates the spatiotemporal variations in drought during the growing seasons of summer maize in the Huaibei Plain.[Method]The analysis was based on the drought severity index(DSI)from 2010 to 2019 calculated using metrological data measured from weather stations across the region.We focused on the top 0-10 cm soil layer and the root zone from the soil surface to the depth of 50 cm.The M-K test and the Kriging spatial interpolation were used to analyze the spatiotemporal variation in droughts over the region at different time scales.[Result]① Since 2016,the severity and frequency of droughts have both significantly increased in the areas of Dangshan,Mengcheng,and Qiaocheng,while decreased in the area of Fuyang.In Suzhou,droughts mainly occurred in 2010-2012 and 2019.Compared to seasonal scale,some drought events exhibited greater severity and higher frequency at the ten-day scale with unpredictable onset.②The highest average annual drought index and frequency both occurred during the sowing-emergence stage,reaching moderate level or above,with the frequencies exceeding 40% .Severe droughts or worse at both timescales occurred in northern Dangshan and central Mengcheng and Suzhou.The frequency of the 0-10 cm soil-layer droughts was higher in the southwest,while the frequency of 0-50 cm soil-layer droughts was higher in the east and north than in other areas.③ At the ten-day scale,the periods with the highest drought severity in each growing season mostly started in the early stage of sowing-emergence,emergence-jointing,and the mid-stage of jointing-tasseling.Severe droughts occurred primarily in August and September.[Conclusion]Since 2016,there has been a significant increase in drought severity and frequency for summer maize in the Huaibei Plain,particularly during the sowing seedling stage.Severe droughts were observed at uncertain ten-day scales,with increased drought frequency.