一、霜冻危害在地膜覆盖栽培中，如果播种不适时，或选用品种不当，往往也会使作物遭受“终霜”或“初霜”的危害。终霜的危害，是指因地膜覆盖播种过早，在春天终霜到来前就出苗子膜外，这时遇到终霜，幼苗叶片或生长点便会遭受冻害。初霜危害，是北作物生长期延长，在秋、冬 First, the frost damage In plastic film mulching cultivation, if sowing discomfort, or improper selection of species, often also make crops suffer “final cream” or “early frost” hazards. The end of the frost damage, refers to the mulching premature mulching, the spring before the arrival of the final frost on the seed film, then encountered the final frost, seedling leaves or growing point will suffer frost damage. The first frost damage is the extension of the northern crop growing season, in autumn and winter