Summer rains, the advent of the rainy season for agricultural production benefits also have disadvantages. Sufficient rainwater to nourish the crops, for greenhouse film, rain easily from the surrounding area of plastic film, leading to the occurrence of some vegetable pests. So some vegetable farmers in the rainy time do not expose the film, the film in the rainy season maintenance kind is also to avoid rainwater poured into the greenhouse membrane of a good method, but then, the heat and moisture in the shed can not be dispersed, it is also harmful to crops. Therefore, it is not enough to put a small wind on the top alone. The arch sheds are open from the surrounding lower wind to cool, in order to prevent outdoor pest in the shed, usually in the vicinity of the arch shed to set up insect nets. Generally, the two sides of the arch-shed agricultural film to pull up 50-60 centimeters high, in advance ready for the pest nets can be, so that in the arch of the formation of "draught", not only reduce the temperature and humidity in the shed, but also effectively prevent the entry of pests.