山西隰县玉露香梨花期冻害成因分析

Cause Analysis of Frost Damage in Flowering Period of Yulu Fragrant Pear in Xixian of Shanxi

利用隰县国家气象自动观测站、香梨花期冻害区南唐户村和乔村区域气象自动观测站的常规观测资料和香梨发育期观测及冻害资料,对2018年4月6—7日山西隰县香梨花期冻害发生的气象条件、果树条件、冻害程度进行研究。结果表明,此次香梨花期冻害程度判断为重度冻害。造成冻害的原因:第1,前期气温异常偏高,导致花期提前10~15 d,致使花期冻害风险加大。第2,超强冷影响,Tmin≤-5.0℃且D≥5 h,超过了果树花期重度冻害阈值Tmin≤-5.0℃且D≥1 h。第3,果树品种不同,冻害程度不同,早熟品种重于晚熟品种;同一果树,树冠顶端受冻率明显低于树冠底部。第4,气象条件相同时,冻害程度随海拔升高减轻;不同地形冻害程度不同,盆地重于山地;迎风面重于背风面。研究此次冻害目的,旨在揭示果树花期冻害的成因,为果树花期冻害预报预警及防御提供科学依据。

Based on conventional observation data and observation and frost damage data in growth period of fragrant pear from Xixian National Meteorological Automatic Observatory and Zhaizi Township Government Regional Meteorological Automatic Observatory,weather condi-tions,fruit tree conditions and freezing damage degree when frost damage occurred in flowering period of fragrant pear in Xixian of Shanxi during April 6-7,2018 were studied.The results showed that the frost damage in flowering period of fragrant pear was judged as serious degree.Causes of frost damage were as below:first,the temperature was abnormally high in the early stage.It caused that flowering period advanced by 10-15 days,and frost damage risk in flowering period increased.Second,impact of super cold air,the lowest temperature lower than-5℃ lasted five hours,which exceeded threshold Tmin≤-5.0℃ of serious frost damage in flowering period of fragrant pear,and D≥1 hour.Third,different fruit tree species had different frost damage degrees,and frost damage degree of early-maturing varieties was more serious than that of late-maturing varieties,and freezing rate of crown top was obviously lower than that of crown bottom for the same fruit tree.Fourth,the degree of frost damage decreased with the increase of altitude when weather conditions were the same.In different terrains,degree of frost damage was different.It was more serious in basin than that in mountain area,while it was more serious in windward side than that in leeward side.The research aimed to reveal cause of frost damage in flowering period of fruit tree,and provide scientific basis for forecasting,early warning and defense of frost damage in flowering period of fruit tree.