基于GIS的陕西省志丹县苹果花期冻害风险精细区划

Fine Zoning of Freezing Damage Risk of Apple Flowering Period in Zhidan County Based on GIS

利用陕西省志丹县国家气象站1960—2022年4—5月日最低温度数据和2021年10月—2022年5月志丹县区域天气站、志丹县果园气象站温度观测数据,采用实地调查、数理统计、随机森林回归和自然断点法进行温度统计分析和苹果花期冻害风险区划。结果表明,志丹县苹果花期冻害主要出现在4月11—17日、24—26日和5月13—15日,以4月11—17日出现频次最多。花期冻害天气约2年一遇,20世纪60、70年代和21世纪00、10年代苹果花期极端最低温度低,冻害影响重,而20世纪80、90年代苹果花期极端最低温度高,冻害影响轻。河谷地由于冷空气堆积,温度低,冻害风险较高,不适宜种植苹果;当海拔高度在1200~1430m时,温度变化剧烈,重、中、轻风险区并存;海拔高度在1430m以上,冻害风险较轻。目前,志丹县约67.2%果园为轻风险区,25.3%果园为中风险区,7.5%果园处于重风险区。对重风险区果园应进行种植结构调整,中风险区果园要加强冻害防御工作。

Used the minimum temperature data from April to May of 1960 to 2022 of Zhidan weather station and temperature observa-tion data of regional weather station and orchard weather station from October 2021 to May 2022,field investigation,mathematical stat-istics,random forest regression,and natural breakpoint method were used for temperature statistical analysis and Zhidan apple flower-ing freezing damage risk zoning.Results showed that apple freezing damage in Zhidan mainly appeared on April 11-17,24-26 and May 13-15,and appeared the most frequently on April 11-17.Average freezing weather was about two years.Extreme minimum temperat-ure of apple flowering period was low in the 1960s,1970s,2000s and 2010s,and freezing damage was serious,while extreme minim-um temperature of apple flowering period was highed in the 1980s and 1990s,and freezing damage was light.Valley land,due to accu-mulation of cold air,low temperature,and high risk of freezing damage,was not suitable for planting apples.When altitude was from 1200 to 1430 m,temperature changed sharply,and risk areas of heavy,medium,and light coexisted.When altitude was above 1430 m,and risk of freezing damage was relatively low.At present,about 67.2%of orchards in Zhidan were light risk areas,25.3%were medi-um risk areas and 7.5%were heavy risk areas.Planting structure of orchards in heavy risk area should be adjusted,and orchards in medi-um risk area should strengthen prevention of freezing injury.