| Under the climate warming background, external growth environment of winter wheat changed a lot. The experimental study on suitable seeding time index and hot damage index of winter wheat in North China has vital theoretical significance and practical value on reasonable arrangements for winter wheat planting, defending hot damage, and promoting practicability of service on winter wheat producing. Basing on stage sowing experiment in2009-2012and heating experiment in2012, this paper, combining with growth and yield data and meteorological data, analyzed suitable seeding time index and hot damage index of winter wheat by using method such as climate suitability model, wavelet transform and analysis of variance and so on. The main conclusion indicated:Result of research on suitable seeding time of winter wheat in North China area showed that active accumulated temperature before winter between399to465℃·d as well as the seeding basic density between372to442104/hm2is the best sowing seeds conditions. We calculated the center date of suitable seeding time in each region in Hebei province basing on distribution of active accumulated temperature. Distribution map of active accumulated temperature start from October5th showed that area suitable for seeding covered Tangshan and Qinhuangdao suitably, and south Beijing and north Tianjin were also suitable for seeding in October5th. Regions, which suitable for seeding around October10th, located between the line Shijiazhuang-Cangzhou and Beijing, mainly including Baoding, Langfang as well as south Tianjin and so on. Regions, which suitable for seeding around October15th, was the line Shijiazhuang-Cangzhou and region, in Hebei province, south to the line. It is not suitable for seeding in Hebei province after October20th. Regional sowing seeds quantities were determined by the seeding time. Compared with suitable seeding center date, seeds quantity should increase7.5kg/hm2each day when sowed late. On the contrary, seeds quantity should reduce when sowed early than suitable seeding date.Basing on winter wheat field heating and growth observation experiment, we analyzed warming effect on the winter wheat grouting process, and determine hot damage index during winter wheat milk-filling period in North China. High temperature, over29.2℃,had inhibited effect to winter wheat milk-filling period, high temperature length and intensity of single day both influenced milk-filling rate, but length was key factor. Basing on length of high temperature, we defined hot damage index during winter wheat milk-filling period in North China Area:When the hourage of high temperature,over29.2℃, beyond average sunshine duration(8.7h), that day was believed that cannot carry on milk-filling process. When the number of high temperature day cannot over3days, this condition was routine event, and production would reduce11%comparing with potential production; When the number of high temperature day achieved for3days but did not reach6days, this condition defined as the mild hot damage, and; When the number of high temperature day outstripped6days, this condition defined as the severe hot damage, and production would reduce over a quarter comparing with potential production. This index had directive function on winter wheat hot damage warning and stable production cultivating. |
