Drought variations of winter wheat in different growth stages and effects of climate trend in Huang-Huai-Hai Plain, China

Abstract

With the purpose of probing the drought characteristic in growth stages and its possible climate factors of winter wheat in Huang-Huai-Hai plain (3H plain) under climate change,based on meteorology data of 5 selected meteorological stations from 1981 to 2010, relative moist index has been calculated to investigate the temporal variability of drought characteristic in five growth stages of winter wheat in 3H Plain in recent 30 years.The results indicated that on the temporal variation, an increasing drought trend was detected in sowing to seeding stage in southern of 3H plain while a contrary trend was found in northern of 3H plain, and the same slight tendency was detected in whole growth period. The drought of growth stages except seedling stage was reduced from north to south. The most severe drought occurred in the seeding to jointing stage and a slight increasing drought trend was detected in north while a decreasing drought trend in south in this stage. A drought trend was detected in heading to maturity, with higher magnitude in south than in north. Tianjin and Shijiazhuang stations were observed to be medium drought and serious drought primarily in whole growth period, the frequency of varying degrees of droughts in Shenxian station was equivalent while Xuzhou and Zhumadian stations were observed to be primarily slight drought from 1981 to 2009. Continuous drought of Tianjin and Shijiazhuang station was serious while sustained drought was not found in Zhumadian station in recent 30 years. With the temperature increasing, aridification might be enhanced in Tianjin and Shijiazhuang stations while a contrary trend was found in Shenxian, Xuzhou and Zhumadian stations in whole growth period of winter wheat. The trend of drought will be alleviated with the temperature decreasing in jointing to heading stage and heading to maturity statge. Drought in sowing to seeding stage will be more obvious in Tianjin and Xuzhou stations with the solar radiation increasing. There was a drought trend detected in Shijiazhuang and Zhumadian stations with the relative humidity decreasing in growth stages. Besides, with the wind speed decreasing, moisture tendency will be found in whole growth period and heading to maturity in southern of 3H Plain. The research results can provide a reference for the simulation study on the impact of drought on yield of winter wheat and developing appropriate measures to reduce droughts in the 3H plain.