宁波市在浙江偏北,属柑桔经济栽培的北缘地区,全区的年平均气温15.8～16.3℃,一月平均气温一般在5℃以上,全年绝对低温出现在12月下旬和2月上旬之间,20年来绝对最低气温在-9.4℃,经常造成柑桔不同程度的冻害。为了摸索在我市的自然条件下晚熟柑桔在树上挂果越冬适期夏采的规律性和可能性,我们于1971～1974年对本市 Ningbo is located in the north of Zhejiang Province and belongs to the northern margin of citrus economic cultivation. The annual average temperature in the region is 15.8-16.3 ℃. The average temperature in January is generally above 5 ℃. The absolute low temperature throughout the year appears in late December and February Between the first ten days, absolute minimum temperature in 20 years at -9.4 ℃, often resulting in varying degrees of citrus frost damage. In order to explore under the natural conditions in our city late-maturing citrus fruits in the tree fruiting summer over the summer regularity and possibility, we in 1971 ~ 1974 to the city