甘肃平凉市苹果花期冻害风险分析及区划

Risk assessment and regional division of frost damage during apple bloom period in Pingliang City,Gansu Province

利用平凉7县（区）气象资料、6个县（区）的苹果物候观测资料和产量资料,对苹果花期冻害指标、因冻减产情况及不同等级冻害发生频率进行了分析。根据平凉近年来苹果花期冻害实地调查,将花期冻害分为三种强度等级即重度（T≤-3.5℃）、中度（T≤-1.5℃）和轻度（T≤0℃）,不同冻害等级对应不同的减产率。在平凉7个县（区）中,华亭花期冻害发生最严重,不同等级的冻害发生1年1-2次,崇信花期冻害则最轻,不同等级冻害3年1次,其他县（区）1-2年1次,全市不同等级冻害的频率分布表现出轻度〉中度〉重度的特点。在此基础上,以冻害灾损率作为风险区划指标,将苹果花期冻害风险分为3个区：高风险区、中风险区和低风险区。本市多数区域属于中风险区和低风险区,重度冻害发生较少,但中度冻害和轻度冻害发生仍较频繁。建议全市在目前果园布局的基础上,应进一步加大中东部低风险区的苹果种植。

Using the meteorological data from 7 counties（ districts）,and the phenological records and output data from 6 counties（ districts） in Pingliang City,Gansu Province,the indicators for frost damage during apple bloom period,the output loss caused by frost damage and the occurrence frequency for different damage degrees were analyzed. According to field investigations of frost damage in recent years,the grades for frost damage during apple bloom period were classified into three levels： serious（ T≤-3. 5℃）,moderate（ T≤-1. 5℃） and slight（ T≤0℃）,which corresponded to different rates of output loss. In the 7 counties（ districts） in Pingliang,frost damage was most serious in Huating where the occurrence frequency of frost damage with different levels was 1-2times per year,and it was most slight in Chongxin where the occurrence frequency of frost damage with different levels was 1 time every 3 years,while the occurrence frequency was 1 time every 1-2 years in other counties（ districts）. The frequency distribution of frost damage for different levels was ordered as： slight moderate serious. Furthermore,the regional division of damage risk for apple was made by using loss rate. The whole city could be divided into 3 regions including high risk region,mid risk region and low risk region,and most part of the city belonged to the mid or low risk region. Serious frost damage occurred rarely,but moderate and slight frost damage occurred frequently in Pingliang. It is suggested that,on the basis of current layout of orchards,the planting area be further expanded in the middle and eastern part of Pingliang where belongs to the low risk region.