洋葱较耐寒,喜湿润。地膜覆盖洋葱,能保持土壤水分,促进腐殖质分解,避免养分流失,提高地表温度(2～8℃),使洋葱充分膨大。同时能控制种蝇在地面产卵,减轻地蛆危害。其单球平均重160克,鳞片厚0.3～0.5厘米,形状好,亩产5000～6000公斤,比露地提早上市15～20天,提高产量83～132％。 Onion more cold, hi moist. Mulch covers onion, can maintain soil moisture, promote humus decomposition, to avoid nutrient loss, increase the surface temperature (2 ~ 8 ℃), the onion fully expanded. At the same time can control the species of flies spawning on the ground, reduce the maggot hazards. The average weight of its single ball 160 grams, scales 0.3 to 0.5 cm thick, good shape, 5000 to 6000 kg per mu, listed earlier than the open 15 to 20 days, raising the yield of 83 to 132%.