How is the green belt between expressways always covered by black nets in summer?

Sun-shading net, also known as sun-shading net, is a new type of special protective covering material for agriculture, fishery, animal husbandry, wind protection and soil covering, which has been popularized in recent years. After being covered in summer, it has the functions of shading, rainproof, moistureproof and cooling. After covering in winter and spring, it still has a certain effect of heat preservation and humidification.

At present, sunshade nets are mainly used in summer, especially in the south. Some people describe that winter in the north is white (covered with film) and summer in the south is black (covered with sunshade net). Using sunshade net to cultivate southern vegetables in summer has become an important technical measure for disaster prevention and seed conservation. At present, the application in the north is limited to vegetable seedling raising in summer. In summer (June-August), the main function of covering the sunshade net is to prevent sun exposure, the influence of heavy rain, the harm of high temperature and the spread of pests, especially to prevent the migration of pests.