丰满人妻熟妇乱又伦精品,四虎影视免费永久在线观看,亚洲精品乱码久久久久久v,人妻中文字幕av无码专区

Black sun screen dust screen

Canopy products > Shading net > Black sun screen dust screen

Black sun screen dust screen

Model of sunscreen: 2.5, 3, 3.5, 4, 6, 8, 12

Model of sunscreen: 2.5, 3, 3.5, 4, 6, 8, 12

Shade color: black, green

Sunshade net, also known as sunshade net, is a new type of special protective covering material for agriculture, fishery, animal husbandry, windbreak, soil cover and so on, which has been popularized in recent 10 years. After covering in summer, it plays a role of keeping out light, rain, moisture and temperature. After covering in winter and spring, it can keep warm and increase humidity.

Generally, the leaf vegetables planted in winter and spring cover the surface of leaf vegetables directly with sunshade net (floating cover) to prevent low temperature damage. Because of its light weight, it is only about 45 grams per square meter, and it will not overwhelm, bend or reduce the commerciality of the grown high leaf vegetables. Because of its air permeability, the leaf surface is still dry after covering, which reduces the occurrence of disease. It also has a certain transparency, after covering, it will not "cover yellow, cover rotten". In 1997, Henan Agricultural University in Longtang vegetable Park, Linying County, protected the winter celery in the shed. The results showed that under the condition of - 6 ℃, there was no ice in the leaves of celery; However, the temperature of the control group, especially the upper and middle leaves, was 1.5 ℃ higher than that of the control group.

       Sunscreen is mainly used in summer, especially in the south. Some people describe it as: the winter in the north is white (covered with film), and the summer in the south is black (covered with sunscreen). In summer, using sunshade net to cultivate vegetables in South China has become a main technical measure for disaster prevention and protection. The application in the north is only limited to the cultivation of vegetable seedlings in summer. In summer (June August), the main function of covering sunshade is to prevent the exposure of hot sun, the impact of rainstorm, the harm of high temperature, the spread of pests, especially to prevent the migration of pests.

       After covering in summer, it plays a role in keeping out light, rain, moisture and cooling; after covering in winter and spring, it also has a certain role in heat preservation and humidification.


       Moistening principle: after the sunshade is covered, because of the cooling and windproof effect, the communication speed between the air in the covered area and the outside world is reduced, the relative humidity of the air is significantly further increased. At noon, the humidity increase value is the largest, generally reaching 13-17%. The humidity is high, the soil evaporation is reduced, and the soil humidity is increased.

       The sunshade is made of polyethylene (HDPE), high-density polyethylene, PE, Pb, PVC, recycled material, brand-new material, polyethylene propylene and other raw materials. After UV stabilizer and anti-oxidation treatment, it has the characteristics of strong tensile strength, aging resistance, corrosion resistance, radiation resistance and portability. It is mainly used in the protective cultivation of vegetables, Xianggu, flowers, edible fungi, seedlings, medicinal materials, ginseng, Ganoderma lucidum and other crops, as well as the aquaculture and poultry industry, etc., which has obvious effect on improving the yield.



久久婷婷国产综合尤物精品| 午夜福利在线观看网站| 白浆 熟女 特警| 亚洲视频在线观看2018| 免费A级毛片无码免费视频草莓| 久久av无码精品人妻系列完整版| 欧美激情另类| 性推油按摩AV无码专区| 亚洲人成网77777亚洲色| 人人爽人人爽人人片AV| AV最新天堂资源在线| 四虎黄色视频网站| 韩国丁香六月| 成人在线免费/AV| 亚洲色欲色欲www| 自慰网站免费观看| 国产免费毛不卡片| 在线 | 一区二区三区四区| 刺激videoschina偷拍| 18岁美女操逼片| 日韩激情AV| 免费看少妇作爱视频| 三级亚洲免费亚洲| 激情婷婷五月深爱五月| 日日操夜夜操啊啊啊| 777人澡人妻人人做人人爽| avtt少妇| 在线一本二本三本免费国产| 漂亮人妻被公强了视频| 高清无码 一区| AV天堂婷婷| 欧美日韩一二三区| 人人人人人人干| 99国产精品无码专区| 人人舔人人插| 精品无码人妻1区 2区 3区| 制服丝袜人妻综合第一页 | 国产不卡午夜| 成年黄网站18禁免费观看一区| 在线精品无码字幕无码AV| 欧美男女精品网站|