1、可增加地温由于塑料薄膜透光好,太阳光能透过薄膜直射到地面上,可使地温升高。北方地区覆膜比不覆膜的早春地温一般可提高2—4℃。 2、保持土壤不分地膜覆盖的土壤表面和薄膜之间形成一个2—5毫米高的不透气小气室,切断了土壤水分同近地层空气中水分交换通道,蒸发的水汽凝结于膜下,水珠受重力作用落到地表,渗入土壤中。土壤水分再度蒸发,再度凝结回落渗入土壤,这样周而复始,构成一个膜下与耕层之间不断 1, can increase the temperature as the plastic film is transparent, the sun can penetrate the film directly to the ground, can make the ground temperature increased. In the north, the temperature in early spring can be increased by 2-4 ℃ than that in the early spring. 2, to maintain the soil irrespective of the film mulching between the surface of the soil and the film to form a 2-5 mm high airtight small air chamber, cut off the soil moisture and near-surface air moisture exchange channels, evaporation of water vapor condensation in the membrane, water Beads fall to the surface by gravity, infiltrating into the soil. Soil moisture evaporates again, once again condensate fall into the soil, so cycle again and again to form a continuous layer between the membrane and tillage