Introduction
The crops will wilt under the strong sunlight in the summer, which can effect the health of the crops and reduce the growth as well.
The shade net could protect the crops against the sunlight, so in summer, more and more farmers choose the shade net for their crops.
However, some clients are confused by the shade rate of shade net, they don’t know how to choose the suitable shade rate for their crops.
Before learning that, we should learn 2 things: light intensity and light saturation.
What is the light intensity?
Light intensity is the luminous flux of light received per unit area, used to indicate the intensity of light and the degree to which the surface area of an object is illuminated.
Light intensity has great influence on photosynthesis of crops. It can be measured by an illuminometer in Lux.
There are many factors that affect the intensity of light.
The intensity of light varies greatly from place to place. In the tropics, the light intensity is higher. At higher latitudes, the light intensity is lower.
The light intensity in different season is not the same. The light intensity in winter is low, and the light intensity in summer is much higher.
The weather also affects the light intensity, dry areas with little rain, the sky is more clear, at this time the light intensity is very high. If it’s rainy, overcast or cloudy, the sun’s light intensity will be much lower.
What is the light saturation of crops.
Light saturation refers to the intensity of light required for a plant to achieve its maximum rate of photosynthesis.
As you can see from the graph above, photosynthesis tends to be saturated when the light intensity reaches the light saturation point of the crop.
When the light intensity continues to increase, the photosynthesis of the crop will decline, because too much light intensity will cause damage to the crop, forcing the crop to reduce photosynthesis to activate the self-protection mechanism.
So you can see a lot of crops wither in direct sunlight, and that’s the crop protecting itself.
Generally speaking, crops that like sunlight have a high light saturation, and crops that like shady environments have a low light saturation.
For crops with high light saturation, he needs a low shade rate, and for crops with low light saturation, he needs a high shade rate.
Why need we choose the shade net?
In summer, under direct sunlight, the light intensity can reach 60,000-100,000 lux. For crops, the light saturation point of most vegetables is between 30,000 and 60,000 lux, such as the light saturation point of chili is 30,000 lux, eggplant is 40,000 lux, and cucumber is 55,000 lux.
Too strong light will have a great impact on crop photosynthesis, resulting in the absorption of carbon dioxide blocked, breathing intensity is too large. Too much light will cause plants to stop photosynthesis, which will reduce the efficiency of plant growth.
Therefore, we need a suitable sunshade net to block the excess sunlight. The use of appropriate shading rate of shade net coverage, can not only reduce the temperature before and after noon in the shed, but also improve the photosynthetic efficiency of crops.
How to calculate the shade rate for crops
As we said, too much sunlight will reduce the growth of crops. Too high shading rate is also not good, after all, the growth of crop also need photosynthesis, if too high shading rate, will also reduce the efficiency of photosynthesis, and ultimately reduce the yield of crops.
So the suitable shade rate is very important for crops, we need choose the different shade rate for the different crops.
The sunlight intensity of every country might be a little different, the direct sunlight intensity in summer of most of countries is from 60,000 lux to 120,000 lux.
To choose the suitable shade rate, you can refer to the formula below:
The shade rate = 1 – ( light saturation of crop / sunlight intensity)
For example, the light saturation of chili is 30,000 lux, the sunlight intensity in your country is 100,000 lux.
the shade rate for chili is : 1-(30,000/100,000)=70%
You also need consider the weather of most of time in summer, if the weather in your country in summer is cloudy, the sunlight intensity should be ruduced.
Normal shade rate for crops
Different plants require different shading rates. Below I describe the light saturation and recommended shading rates of several commonly used crops.
Shading rates can be adjusted slightly according to your local light intensity. In areas with high light intensity, the shading rate can be slightly higher. In areas with low light intensity, the shading rate can be chosen to be lower.
Tomato
The light saturation of tomato is about 70,000 lux, so the suitable shade rate would be 10%-30%.
Cucumber
The light saturation of cucumber is about 55,000-60,000 lux, so the suitable shade rate would be 30%-50%.
Chili (Pepper)
The light saturation of chili is about 30,000 lux, so the suitable shade rate would be 50%-70%.
Long bean
The light saturation of long bean is about 20,000-50,000 lux, so the suitable shade rate would be 50%-80%.
Cabbage
The light saturation of long bean is about 40,000 lux, so the suitable shade rate would be 40%-60%.
Lettuce
The light saturation of lettuce is about 5,000-10,000 lux, so the suitable shade rate would be 80%-90%.
Spinach
The light saturation of spinach is about 5,000-10,000 lux, so the suitable shade rate would be 80%-90%.
Celery
The light saturation of celery is about 40,000-45,000 lux, so the suitable shade rate would be 50%-60%.
Eggplant
The light saturation of celery is about 40,000 lux, so the suitable shade rate would be 40%-60%.
Mushroom
Mushroom is a little different from other green crops, there is not chlorophyll, so it can not carry out photosynthesis, it do not need direct sunlight. The shade rate would be above 95%.
Conclusion
The light-loving vegetables need lower shade rate, Including most jackets, melons and cowpeas, their light saturation point is above 40,000 lux, requiring strong light to grow well.
The low-light tolerant vegetables need higher shade rate. Including lettuce, spinach, chrysanthemum chrysanthemum, coriander, fennel, radish and other rapid natural vegetables. their light saturation point is about 10,000-20,000 lux, can grow well under weak light. If the light is too strong, it will reduce the yield and quality of crops.
Some other crops including cabbage, leek, celery, beans, peas and other vegetables, its light saturation point is 30,000 to 40,000 lux, requiring moderate light intensity to grow well.
If you have any questions or need suggestions, I am happy to hear from you, we can have a talk at any time. Hope this blog is useful for you to choose the most suitable shade rate.
