黑龙江6+1开奖结果:What is the function of black and white mulch?
黑龙江体彩61开奖时间 www.ewlqe.icu Plastic film has good properties in light transmittance, heat preservation, tensile strength and aging, which is of great significance to the growth, yield and income of greenhouse crops. Plastic film can increase temperature, make crop growth period, quality and yield high. Different membranes have different characteristics and advantages.
Characteristic of white film: The thermal radiation rate of white film is 80%-90%, close to that of transparent film, and its transmittance is only 40%. It has certain inhibition effect on weeds. It is mainly used for flat mulching, which can better solve the problem of serious grass damage caused by transparent plastic film mulching.
The characteristics of black film: the transmittance of black film is only 1%-3%, and the thermal radiation is only 30%-40%. Because it is almost opaque, weeds can not germinate and photosynthesis, so the weed control effect is remarkable. Under sunlight, black mulch can increase temperature quickly and humidity is high, but the heat transferred to soil is less, so the effect of increasing temperature is not as good as that of transparent mulch, and it also has cooling effect in summer daytime. When used, it is laid flat on the ground so that the crop can be exposed outside the film, and it can also be laid flat between the rows of the crop.