What properties does the sunshade net have?

Most domestic sunshade nets are made of polyolefin resin, which is processed and drawn and then woven into a lightweight, high-strength, aging-resistant new mesh-shaped plastic covering material. Covering in summer can provide sun protection, heatstroke prevention, drought protection, moisture conservation, wind and rain protection, and pest and disease protection. Covering in winter can prevent freezing and heat preservation.

(1) Shading, cooling, and moisture conservation. The shading rate of sunshade nets produced in my country is currently between 25% and 75%. Different colors of sunshade nets have different light transmittances. For example, the light transmittance of black sunshade nets is significantly lower than that of silver gray sunshade nets.

Because the sunshade net reduces the light intensity and the radiated heat of light, it has an obvious cooling effect, and the higher the outside temperature, the more obvious the cooling effect. When the outside temperature reaches 35 to 38°C, the general cooling range can reach 9 to 13°C, and the maximum drop can be 19.9°C. The most obvious cooling effect is on the surface, followed by the area above the ground, within 20 centimeters underground, and within 5 centimeters above and below the plant leaves. Covering the sunshade net in hot summer can generally reduce the surface temperature by 4 to 6 degrees Celsius, with a maximum temperature of 19.9 degrees Celsius. The temperature 30 centimeters above the ground can be reduced by 1 degrees Celsius, and the temperature 5 centimeters underground can be reduced by 3 to 5 degrees Celsius. If the surface is covered, the temperature 5 centimeters underground can be reduced by 3 to 5 degrees Celsius. Reduce 6~10℃.

After the sunshade net is covered, the solar radiation is reduced, the ground temperature drops, the wind speed weakens, and the evaporation of soil water is reduced. Generally, the evaporation is only 30% to 40% of that in the open field, which has obvious drought prevention and moisture conservation. function.

(2) Windproof, rainproof, and pest-proof. The sunshade net has high mechanical strength and can slow down the losses caused to vegetables by typhoons, heavy rains, hail and other disastrous weather.

The greenhouse is covered with sunshade net. During a typhoon, the wind speed inside the greenhouse is only about 40% of the wind speed outside the greenhouse, and the wind blocking effect is obvious.

According to calculations by the Agricultural Meteorological Station in Zhenjiang City, Jiangsu Province, plastic greenhouses covered with sunshade nets can reduce the impact of heavy rain on the ground to 1/50, and reduce rainfall in the greenhouse by 13.29% to 22.83%.

The silver-gray sunshade net has an obvious effect of avoiding aphids and can effectively reduce the spread of viruses. Covering the netting room with a sunshade net can prevent damage from external pests and diseases. According to Xuzhou City's experimental measurements on autumn tomatoes, the incidence of plant virus diseases was 3% when covered with silver-gray sunshade nets, and up to 60% when not covered.

(3) Anti-freeze and thermal insulation In order to improve the utilization rate of the sunshade net and reduce the coverage cost, it can also be used to prevent early frost in late autumn, late frost in early spring and frost damage in winter. According to measurements, the silver-gray sunshade net can increase the surface temperature by 1.3 to 3.1°C at night, increase the ground temperature by 0.9 to 1.5°C within 5 cm, and increase the leaf temperature by 1.0 to 2.0°C.