1973年冬至1974年春,闽北建瓯县南门大队3800株6年生芦柑遭受了一次罕见的大冻害。其中3、4级冻害株占56.3％,落叶枯枝严重,当年失去结果能力;1、2级冻害株占43.7％,虽然受害较轻,但当年有效化果显著减少(分级标准如下表)。为了使冻后柑株迅速恢复树势,保持当年有一定产 From the winter of 1973 to the spring of 1974, 3800-year-old six-year-old Luganan from the south gate of Jianou County in northern Fujian suffered a rare frost damage. Of which 3 and 4 frostbite strains accounted for 56.3%, deciduous serious litter, then the ability to lose the result; 1,2 grade frostbite strains accounted for 43.7%, although less affected, but the effective results were significantly reduced (grading standards in the table below). In order to quickly restore the frozen citrus tree vigor, to maintain a certain production that year