兰州地区今春发生的晚霜冻,给果树生产带来了严重危害,使果品减产三分之一至二分之一。霜冻发生后,我们先后在安宁堡、费家营、雁滩、彭家坪及东岗等地进行了调查,现将调查结果分述如下。一、霜冻的特点:今年的霜冻是由西伯利亚寒流侵袭所造成的平流霜冻。其特点是:出现 Late frosts in Lanzhou this spring have brought serious harm to the production of fruit trees, reducing fruit yields by one third to one half. After the frost occurred, we conducted surveys in Anning Fort, Feijiaying, Yantan, Pengjiaping and Donggang. The findings are as follows. First, the characteristics of frost: This year’s frost is caused by the invasion of the Siberian cold spell frost. Its characteristics are: appear