Tunnel film: prevent sunburn
Politiv has developed a film especially for the more intense weather conditions we face. High solar irradiation resulting in crop burns. That is why Politiv is introducing a revolutionary line of Diamond® films. The main characteristics of this type of film: high light transmission; high and unique light diffusion; high thermal.
Prevent sunburn by breaking direct sunlight
Direct sunlight (undifferentiated light) produces a "shadow" effect and causes "sunburn" . This is because the sun's rays shine directly on the leaves and fruits.
Light Distribution
To prevent direct radiation, additives are added to scatter the direct light, preventing the "shadow" effect and "sunburn". Light scattering increases photosynthetic efficiency by bringing light from all directions.
Differentiated light, not just numbers.
It turns out that not only the amount of diffused light is important, but also the way the light is diffused plays a special role in how the plants can benefit from the diffusion. By choosing the right raw material, we obtained the ideal combination between light transmission and light diffusion.
The photo shows the different films illuminated with a laser to demonstrate the light distribution.
- Left clear film. Clearly direct radiation;
- Right the common diffuse film with still a clear core in the light;
- Center the light radiation is completely broken open.
Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that can be perceived by the human eye. Visible light is usually defined as light with wavelengths in the range of 400-700 nanometers (nm), between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).
Photosynthetically active radiation (PAR) denotes the spectral range (waveband) of solar radiation from 400 to 700 nanometers that photosynthetic organisms can use in the process of photosynthesis. This spectral range corresponds more or less to the range of light visible to the human eye. PAR is essential for all crops. Rule of thumb: 1% addition in Light means 1% addition in the crop.
Thermicity
Some of the energy radiation is in the IR range of 700 to 1,400 nm. This range is invisible to the human eye. IR energy is absorbed by the sun during the day. Some of the IR - thermal IR - is emitted at night. This lowers the temperature in the greenhouse. Blocking the IR radiation from the greenhouse to the atmosphere, i.e. outside, minimizes heat losses and reduces the risk of freezing. Especially in cold night areas, it is very important to protect the crop with a good thermal film, which ensures that less than 15% of the IR escapes.
Current status
Diamond® films are successfully sold worldwide. Diamond® 15 is widely used in Oxnard California and in Mexico, both areas with strawberry and raspberry growers, who show an increase in light transmission and light diffusion. Politiv, in collaboration with the University of Almeria, is conducting an ongoing field trial comparing Diamond® films with regular films. So far, it seems that there is an advantage in favor of Diamond films (final results expected in spring 2021). In the area of Huelva, known as an important berry-growing center, several tunnels have been covered with Diamond® film that provides a significant increase in yield.
Summary
The Diamond® film range is an ideal combination of three factors:
- Excellent light transmission for maximum yield;
- Excellent light dispersion for the best crop;
- Excellent thermals for minimal energy losses, risk of frost and heating costs.
All Diamond® films can be supplied:
- Sulfur resistance up to 5,000 ppm S;
- Anti Condensation;
- Enhanced Strength;
- Anti fog for cold or hot climate;
- AntiDust;
- Bee friendly and UV open.
As always, we like to set a new bar in terms of innovation.
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Gerben van Veldhuizen Fruitprotection specialist My mission is to help as many fruit growers as possible get a good harvest. |
