How many degrees can the temperature of plant mulch film increase?

The biggest function of plastic film mulching cultivation is to increase soil temperature. The temperature in 0- 10 cm deep soil layer can be increased by 1-6℃ after being exposed to sunlight during the daytime in the low temperature period in spring, and the highest temperature can be above 8℃. In high temperature period, if there is no shading, the surface temperature of soil under plastic film can reach 50-60℃, and the surface temperature of soil will be higher when it is dry. However, when there is crop shading, or when the plastic film surface is covered with soil or silt, the soil temperature is only 1-5℃ higher than that in the open field, and when the soil is wet, it will be 0.5- 1.0℃ lower than that in the open field, at most 3℃ lower. Affected by cold air at night, the soil temperature under plastic film is only 1-2℃ higher than that in open field. The warming effect of plastic film mulching varies with different mulching periods, mulching methods, weather conditions and plastic film types.