北疆棉区终霜冻的发生时间是非正态分布 ,发生的强度也无明显规律 ,对棉苗生长影响较大的终霜冻是 4月下旬出现的低温强度较大的霜冻。终霜冻的发生形式有平流降温型和辐射降温型两种。避免和减轻终霜冻对棉花生长影响的对策有 :( 1 )加强中长期天气预报 ;( 2 )确定适宜的播种期 ;( 3 )及时放苗封洞 ;( 4)对遭受霜冻的棉田要加强管理等 The occurrence time of the final frost in the northern cotton area is non-normal distribution, and there is no obvious regularity of occurrence. The final frost, which has a great influence on the growth of the cotton seedling, is the frost of low temperature strength which appears in late April. The final frost occurs in the form of advection cooling and radiation cooling two. Strategies to avoid and mitigate the effect of final frost on cotton growth are: (1) to strengthen the mid- and long-term weather forecast; (2) to determine the appropriate sowing date; (3) to promptly release the seedling; (4) to strengthen the frost- Management and so on