Hail is a type of solid precipitation that causes significant damage to crops, including complete crop losses and even tree death. The wounds it creates on branches, leaves, and fruits serve as entry points for various pathogens that can lead to disease development.
In recent years, due to climate change, hailstorms have become more frequent and occur during periods when they were previously less common. This can affect critical stages of crop growth, adding to the damage caused by hail itself. As a result, anti-hail nets have emerged as an efficient solution for protecting agricultural crops against hail damage.
Depending on the region, these nets are used in crops such as stone and pome fruits (apple, pear, peach, cherry), table grapes, bananas, and more.
Anti-hail nets are made from high-density polyethylene, and their characteristic weave provides them with greater mechanical strength. They must be able to withstand the weight of hail accumulation and the force of stone impact without deforming, maintaining their structure. Therefore, their weave needs to be strong and resistant.
The most used densities for anti-hail nets are 2.6×3 and 5×4 threads/cm2. The choice of density depends on the crop, climatic conditions of the area, shading requirements, and the specific goals such as advancing or delaying the harvest.
In apple and other fruit orchards, it is common to install anti-hail nets with a density of 5×4 threads/cm2 on the sides of the structures to protect against the apple moth or codling moth (Cydia pomonella).
There is a wide variety of colors available for anti-hail nets, including transparent, black, white, red, and more. These colors provide varying levels of shading, light diffusion, and spectral modifications, which can influence factors such as coloration, sugar content, plant vigor, and more.
In apple orchards, for example, the color of the anti-hail net used depends on the color of the fruit’s skin. For green and yellow varieties like ‘Granny Smith’ and ‘Golden Delicious’, black anti-hail nets are commonly used. For bi-colored varieties such as ‘Gala’, ‘Fuji’, and ‘Pink Lady®’, gray and white nets are primarily used.
Instalación de malla antigranizo
Generally, anti-hail nets are installed over the crops like a roof, using sturdy and securely fastened structures composed of cement or wooden anchors and poles, to which the wiring that will hold the nets is attached. Depending on the type of installation, elastic elements can be used to allow for the evacuation of hail. Specially designed accessories are used to secure the nets, ensuring a strong and durable connection that does not damage the nets.
Sometimes, the crops are covered in rows, surrounding the row of trees.
Types of Installation
There are different types of anti-hail nets installations. Some of them allow for direct and continuous discharge of hail in the streets or end rows through a system of slopes and elastics. Other mechanisms support the hail on the net, meaning that it remains on the mesh until it melts.
Most of these systems allow for the anti-hail nets to be collected over the tree rows during periods when there is no hail risk. The joining of the meshes in the center of the plantation rows is done using elastics, connecting accessories, or zipper systems.
If there are strong winds in the area, windbreak structures ranging from 3 to 6 meters in height can be installed to protect the anti-hail structure.
Advantages of anti-hail net installations include
- Protect the crop from the harmful effects of hail.
- Reduce irrigation needs by decreasing air velocity and evapotranspiration.
- Improve fruit quality by reducing damage from sunburn, scorching, and certain physiological disorders, as well as influencing coloration.
- Protect against damage caused by birds and bats.
- Increase profitability of the operation by choosing the color of the net to advance or delay harvest, seeking the best market prices, and above all, providing protection.
