中文摘要：

为给基层农情工作者及时准确判断冬小麦霜冻害灾损程度,以及为生产者采取科学有效的补救措施降低灾害损失提供依据,通过对冬小麦受害地区进行灾情田间调查,结合当地气象资料、农情专家评定以及多年农情工作经验,依据受冻株率及减产率等指标将冬小麦霜冻害分为无、轻度、中度、重度和特重度5个等级。其中,小麦轻度霜冻害受害植株少部分叶片受冻,部分受冻部位可以恢复生长,一般减产5%左右;中度霜冻害植株部分叶片受冻,受冻部位难以恢复生长,一般减产5%~30%;重度霜冻害植株冠层大部分叶片受冻,受冻部位不能恢复生长,减产达30%~50%;特重度霜冻害植株叶片大部分受冻,数日后叶尖干枯,减产达50%以上。

英文摘要：

Frost damage of winter wheat is a main meteorological disaster for winter wheat production in North China. For the field monitoring of this meteorological disaster on winter wheat and evaluating its severity, informative grading criteria for classifying the frost damage on winter wheat would be established. In this study, based on the field tracking investigation to winter wheat, the practical experiences of investigating and assessing the meteorological and agricultural data and the morphological characteristics of freezing-suffered wheat, the grading criteria of frost damage to winter were established with 5 grades of no frost damage, mild frost damage, moderate frost damage, severe frost damage and serious frost damage. The characters of each grade were as followed. The wheat suffered from mild frost damage appeared that a few of leaves were frostbitten, parts of them could resume growth and the yield reduction rate was about 5%. The wheat suffered from moderate frost damage appeared that some leaves of wheat were frostbitten, the growths of those parts were difficult to restore and the yield reduction rate was by 5% -30%. The wheat suffered from severe frost damage appeared that most leaves of plants leaf canopy were frostbitten, the growth of this part could not be re stored and the yield reduction rate was by 30%to 50%. The wheat suffered from extraordinarily se vere frost injury appeared that a large number of leaves were frostbitten, the leave tips were dry a few days later and the yield reduction rate was more than 50%. This grading standards established on the damage of frost on wheat, which would provide a guide for agricultural workers to accurately evaluate the severity of frozen damage and pave the way for producers to adopt scientific and effective remedy measures to reduce losses.