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小麦霜冻害一般是从拔节到抽穗期土壤表面温度降低到0℃左右所造成的灾害。在我国华北平原中、南部和黄淮平原的小麦常受这种危害,长江中下游地区弱冬型小麦以及青海高原的春小麦有些年份也会遭受霜冻的危害。麦苗受冻后,叶片呈水浸状或叶凝霜,因细胞结冰而叶片发硬,日出以后冰、霜融化,叶面呈暗绿色,萎蔫下垂。受害轻者尚能恢复,重者则干枯发脆。尤其是在小麦拔节后5～15天内,其抗冻能力最弱,受害后会严重减产。小麦霜冻害的防御措施主要有:1.灌溉。霜冻前进行灌溉可保温1～2℃。据研究,在砂壤土小麦株高35公分的条件下,灌溉后3天地面温度可提高2℃,地面温度日振幅减小8℃左右。
Wheat frost damage is generally caused by the surface temperature from jointing to heading to about 0 ℃. In the North China Plain, wheat in the southern and Huanghuai Plain is often endangered. The weak winter wheat in the middle and lower reaches of the Yangtze River and the spring wheat in the Qinghai Plateau also suffer some frost damage in some years. After the wheat germ is frozen, the leaves are flooded or frost-like, the leaves are hardened due to the freezing of cells, and the ice and frost are melted after sunrise, the leaves are dark green and wilted. The victims of light can still recover, while those who are dry crisp. Especially in wheat within 5 to 15 days after the jointing, its weakest antifreeze ability, will severely reduce the yield. Wheat frost damage prevention measures are: 1. Irrigation. Frost before irrigation can keep warm 1 ~ 2 ℃. According to the research, under the condition of 35 cm height of sandy loam soil, the ground temperature can be increased by 2 ℃ three days after irrigation and the daily amplitude of ground temperature can be reduced by about 8 ℃.