Views: 0 Author: Site Editor Publish Time: 2025-04-02 Origin: Site
As global climate change intensifies, frequent extreme weather has become a major threat to agricultural production. According to the Food and Agriculture Organization of the United Nations, the global agricultural losses caused by hail disaters exceed US$5 billion each year.As an economical and effective physical protection method, warp knitted anti-hail nets are becoming the core equipment in the modern agricultural disaster prevention system with their scientific design and precise protection performance
Warp knitted anti-hail nets are now widely seen in various crop planting areas. Orchards are one of their key "guard positions". Whether it is an apple orchard, pear orchard, vineyard, or peach orchard, the fruits in the fruit-bearing period are fresh and fragile. When hail strikes, the peel is smashed and the flesh is damaged, which not only affects the appearance, but also easily breeds bacteria, resulting in a large number of fruit falling, and even a total crop failure in severe cases. Vegetable planting areas are also inseparable from anti-hail nets. Tomatoes, cucumbers, leafy vegetables, etc. grown in the open air encounter hail during the peak growing season, and their leaves are smashed, stems are broken, and the quality of vegetables plummets. The anti-hail net is built above the fruit tress, just like putting on a layer of "protective clothing" for the orchard, which can effectively block the direct impact of hail
Uesd of make warp knitted anti-hail nets is directly related to their protective performance and service life. At present, the mainstream raw materials for warp knitted anti-hail nets are mainly polyethylene(PE). Polyethylene has good flexibility, corrosion resistance and anti-aging properties. Its molecular structure is stable and can withstand the test of outdoor environments such as sun, rain, and alternating hot and cold for a long time. It is not easy break or damage. The warp knitted anti-hail net made of polyethylene is light in texture, easy to install and disassemble, and has a certain resistance to ultraviolet rays. It can maintain a high strength over a period of several years to ensure that the protective effect is not compromised.
Warp Knitted anti-hail net is rigorous and delicate. The common shape is crescent-shaped, with encrypted two sides, and some also have threading holes. It is woven by three combs on the war machine. The process is shown in the figure below:
GB1: 1-0/0-1//
GB2: 1-0/1-2//
GB3: 0-0/3-3/0-0/3-3/0-0/3-3/0-0/1-1/0-0/1-1//
The on-site installation and production of warp-knitted hail-proof nets is a systematic project that needs to be closely adapted to the characteristics of crops and field layout.
Early measurements are crucial. Technicians must accurately measure the area and shape of orchards or farmland, taking into account factors such as terrain undulations and the distribution of surrounding obstacles. For orchards, the height of the hail net is determined based on the variety, age, and crown size of the fruit trees. It is generally 1-2 meters higher than the top of the crown to ensure that there is enough space under the net for fruit tree growth and agricultural operations, and that the fruit area is fully covered. For vegetable fields, the height is estimated based on the vegetable growth cycle, which not only protects the seedling stage, but also takes into account the height of the plants in the middle and late stage. The installation height is flexibly adjusted between 1.5-2.5 meters.
The construction of the support system is a key step in the installation. Common materials include steel pipes, cement columns, wooden poles, etc. As columns, which are buried deep underground and fixed. The ground part is arranged at intervals of 3-5meters, and then connected with crossbars and diagonal braces to from a stable farme to ensure that it can bear the weight of the anti-hail net and resist wind and rain. In windy areas, the bottom needs to be reinforced with anchors to enhance the overall wind resistance.
Knitted anti-hail nets requires skill. Multiple people work together to unfold the net and slowly cover it along the frame to ensure that the edge of the net is tightly bound to the supporting structure without leaving any gaps to prevent hail from entering. For large areas, the nets are laid in sections and spliced tightly. The splicling is reinforced with special ropes or connectors. After completion, the tightness of the net is checked. If it is too loose, it is easy to be damaged by wind, and if it is too tight, the force is uneven. Only when it is properly tightened can it "stand guard" steadily when hail is raging, allowing crops to grow safely under the protection of the anti-hail net and usher in bumper harvest season after season.
Installation example:
In the apple producing area of Aksu, Xingjiang, the warp knitted anti-hail net adopts a layered erection mode, with the upper layer being a 1.2cm aperture main net and the lower layer being an additional 0.8cm aperture dense net, forming a double interception for hail with adiameter of 3-5cm.
Actual measured data shows that this combination can reduce the impact force of hail by 87%, effectively protecting the integrity of the apple skin.
Shangdong Shouguang Vegetable Base innovatively uses a liftable anti-hail net, combined with an intelligent weather monitoring system. When hail weather is predicted, the system automatically raises the net to a height of 3.2 meters, ensuring normal growth space for vegetables while resisting severe convective weather. The system reduces the loss rate of vegetables from hail disasters from 35% to 6%.
In the tobacco planting area of Yunnan, a regional warp knitted hail prevention network group was established, which achieved full coverage protection of 3000 mu of tobacco fields through grid layout. In conjunction with the radar early warning system, a "monitoring-early warning-protection" closed loop was formed, reducing the compensation rate for tobacco hail disasters by 62%.
