ReduSol, the basis of better light control
Stress through too much light or heat is detrimental to production. ReduSol has taken light control in the greenhouse to a higher level worldwide.
Radiation from the sun is the basis of all production. In principle, more light means more production. Therefore, it is essential to allow the maximum amount of light emission that a crop can withstand. That amount varies greatly per crop and even per variety.
Crops can experience a lot of stress from too much light. It would then be wise to determine whether it is because the plants can no longer process the light particles (photons), which then cause damage, or because the crop simply becomes too warm, which would lead to a different type of damage or quality loss.
Light stress
When there is too much light, the ‘antennae’ in the foliage change shape. They do that to protect themselves. The result is that they can temporarily absorb less light and the photosynthesis process becomes poorer. The excess solar energy is converted into heat, causing the leaf to warm up.
This protection only works to a certain extent. In the event of more light, free radicals are formed; these are harmful substances that can affect cell membranes or the DNA.
Heat stress
In principle, all processes in the plant occur faster at higher temperatures. Therefore, it is in the grower’s interest to maintain the greenhouse temperature. But every crop knows its limit; beyond that limit efficiency starts to decrease and, at a certain point, heat stress occurs, resulting in damage to proteins, whole cells or tissues.
If it is necessary to reduce both heat and light, ReduSol is the recommended coating. ReduSol has been on the market for over twenty years and has led to a revolution in the way of light reduction. Compared to traditional chalk methods, the advantages of ReduSol are huge: the coating can be applied very evenly so that no growth differences in the crops occur. ReduSol is also very wear-resistant, yet it can be completely removed using ReduClean without leaving any trace, which would otherwise lead to growth differences.
The continuous growth of sales proves that there is a great need worldwide for a coating that enables the grower to control light and heat. The properties of ReduSol enable the exact amount of light emission during the season that the crop can use efficiently.
An insight into crops and light
For optimal control, an insight into two matters is necessary: the progress of photosynthesis efficiency during increasing light levels and local climate conditions over the year.
To a certain extent, every crop produces more when light levels increase. For larger crops, there is a so-called photoresponse curve (see Figure). The form is always the same: first an increase of the photosynthesis efficiency during increasing light levels, then the efficiency levels off and falls back at the top of the graph. It varies per crop (and sometimes per variety) where the top lies and how quickly damage occurs.
For a proper lighting plan, it is necessary to match the insights from the photoresponse curve with the progress of the local light levels over the year. From that it can be concluded when light needs to be kept out and to what extent. Sometimes it is sufficient to apply a thin layer of ReduSol over the course of several weeks, but in other regions a thicker layer, or several layers on top of each other, is the best way.
Growers who approach the matter in this way will get the most out of their crops.
Light intensity
A much easier way is to only look at the maximum permissible light level in Watts. This also varies per crop. A coating is needed during the months when the amount of sunlight exceeds this level. Finally, light intensity (daily light integral, DLI) also plays a role. Quite a few crops can only process a certain amount of light particles a day; therefore, it makes no sense to offer more. This would only lead to more heat and possible damage. ReduSol is the recommended choice for shadow plants and crops with a DLI medium. Crops that can withstand more light would benefit more from ReduHeat, ReduFuse or ReduFuse IR.
The palette of coatings of ReduSystems has increased the control possibilities for the grower significantly. However, the choice has become more complicated. In many cases, the ReduWizard on our website can provide a customized solution. If that is not sufficient, we can also provide personal advice.
