江苏省冬小麦湿渍害的风险区划

选取能较好反映冬小麦春季湿渍害特征的3个气象因子:旬降雨量、旬日照时数和旬雨日,计算了江苏省1960—2008期间历年3—5月这3个因子的逐旬统计值,分析了这些因子与冬小麦气候产量的关系,研究结果表明:(1)春季旬降雨量、旬雨日和旬日照时数对江苏省冬小麦气候产量有显著影响;(2)通径分析显示,旬降雨量和旬日照对气候产量有直接影响,而旬雨日对气候产量有间接影响;(3)构建了一个湿渍害判别指数Q用来判别湿渍害发生年份,并结合江苏省各地湿渍害年发生频率和冬小麦气候减产率,建立了冬小麦湿渍害风险指数模型;(4)利用所建风险指数模型对江苏省冬小麦的湿渍害风险进行了区划和评估,并提出了各风险区的防御对策。

Risk division on winter wheat suffering from spring wet damages in Jiangsu Province

Spring wet damage has brought a serious impact to the growth and yield of winter wheat in the southern China. Efficient risk divisions of wet damages shall play an important role on the safe production of winter wheat. In this paper, some meteorological factors such as ten-day precipitation, ten-day sunshine time, and ten-day rainfall days were selected to reflect the characteristic of wet damage occurrence in spring and the data of these factors in all springs of 49 years (from 1960 to 2008) were used to analyze the relationship between them and the climate yield of winter wheat in Jiangsu Province. The results were followed as: (1) In Jiangsu Province, the change of the above factors in the springs have been significantly associating with the fluctuation of the climatic yield. (2) The path analysis showed that the ten-day precipitation and ten-day sunshine time were the two direct factors influencing on the climatic yield of winter wheat but the ten-day rainfall days had indirect impact on it. (3) Q index was used to distinguish the wet years form the years of other types and establish an integrated risk exponential model about the wet damage of winter wheat combined with the occurrence frequency of wet damages and the drop percentage in winter wheat yield. (4)The established risk exponential model were applied to evaluate the risks of winter wheat suffering from wet damage in the different regions of Jiangsu Province and divide the regions of different risk grades. Consequently, some measures of prevention from the wet damage were put forward and it will provide a scientific basis for the prevention from wet disasters and mitigate the loss of the winter wheat production in Jiangsu Province.