The maximum effect of plastic film mulching cultivation is to improve soil temperature, and the 0-10 cm deep layer can increase the temperature by 1-6 ℃, and up to 8 ℃, when the film is covered by the sun during daylight. When entering the high temperature, if no shade, the surface temperature of the soil under the film can reach 50-60 ℃, when the soil is dry, the surface temperature will be higher. However, when there is crop shading, or plastic film surface with soil or silt cover, TWAIN only 1-5 ℃ than open field, soil moisture twain will be lower than the open field 0.5-1.0℃, the highest can be low 3 ℃. At night, due to the influence of cold air, the soil temperature under the film is only 1-2 ℃ higher than open field. The temperature-increasing effect of plastic film mulching varies with the covering period, covering mode, weather condition and film type.
Because of the strong gas tightness of the film, the film mulching can significantly reduce the evaporation of soil moisture, stabilize the soil moisture, and keep moist for a long time, which is beneficial to root growth. In arid regions, artificial entropy and entropy can be used to sow drought resistance. In the case of drought, the soil water content in 0-25 cm depth is generally more than 50% higher than the open field. With the deepening of the soil layer, the water difference gradually decreases.