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The field of plant lighting is one of the fields of agricultural lighting that has developed rapidly in recent years. LED has many advantages such as high luminous efficiency, low heat generation, small size and long life, and has obvious advantages in the field of plant lighting. With the maturity of technology, companies have switched from the general lighting market to the field of plant lighting, and plant lighting has broad prospects.

So, in the process of development, what are the current problems of LED plant lighting? What is the current proportion of LED in plant lighting? Compared with the advantages and disadvantages of LED and other light sources in plant lighting, what is the future development trend of LED plant lighting? At the recent plant lighting conference, the guests had a detailed discussion on this.

1. How do you view the current development of the entire plant lighting industry?

Fang Wei: The future of the plant lighting industry should be very optimistic. Judging from the current sales of plant products, whether it is an entry-level vegetable leaf or a healthy ingredient, or even a medicinal material that will become a future trend, whether in China or Taiwan and Japan , The prices of these products are getting higher and higher, and the future of plant lighting must have a bright future. The premise is that your product must have features.

The product has its own characteristics, and the next thing that determines the success of the industry is to see whose business marketing model can be implemented smoothly. The life cycle of plant products is very short, but many people will not sell them, and the products they grow cannot be sold. In fact, products need different routes. From fresh vegetables to processed products, from semi-finished products to finished products, when the products become diversified, the sales channels also become diversified. Sales naturally went up.

2. At present, what is the market share of LED in plant lighting fixtures?

Xian Yulun: Currently, the plant lighting fixtures used in greenhouses are mainly high-pressure sodium lamps in the world, and fluorescent lamps in China. LED lamps are rarely used. In recent years, the application growth rate in the field of cannabis has accelerated, and some plant factories also have LEDs are used, but generally speaking, the proportion of LEDs is still very small.

3. What are the advantages of vegetables grown with plant lighting compared with ordinary vegetables?

Jiang Jingjing: There are several major features. The first major feature is that vegetables grown in plant factories are very safe. Only in a controllable environment can be illuminated with LED lights, and its environment and nutrient solution can be controlled manually. Beyond green vegetables, and without the need to use any pesticides and herbicides in plant factories, our nutrient solution avoids heavy metal pollution in traditional soils. The second feature, because we are an artificially created shortcut environment, the air is filtered, the water is purified, and the dust and bacteria levels are very low. The third feature is that the products of the plant factory are very fresh. Compared with the loss caused by other traditional agricultural planting and long-distance transportation, the plant factory is placed around the big city. it's the same.

In addition, compared with traditional agriculture, plant lighting factories can be customized. Traditional agriculture is limited by the fact that climate and temperature change throughout the year. Although greenhouses can now eat off-season products, plant factories have no concept of seasons at all. The product is the same all year round and efficient.

Fang Wei: We should have this kind of thinking: the value of vegetables in plant factories is different from that of ordinary vegetables. In Taiwan, vegetable factory dishes only need to pass rigorous scientific standard data verification. Indoors, the detection of air dust is the technical standard that the dust content of one cubic centimeter is 100,000. If this standard is met, it is identified as clean. The clean room standard is 10,000 dust per cubic centimeter, while the average food processing factory is 100,000. The plant factory is not a clean room, so it is enough for the plant factory to meet the environmental requirements of the food processing factory. The dishes that come out have reached the standard of eating raw.

4. Has there been any research on vegetables grown in plant factories that have defects in function or performance? Will artificial planting change the structure of vegetables, or other similar genetic problems?

Fang Wei: Artificial light is basically the same as sunlight, and there is no difference in the growth of plants. The only difference is that if the plant is reddish, if you use an accurate spectrum, it will grow lettuce with normal red leaves, but you say that the vegetable will be different without anthocyanins, but it will only lack some nutrients. Maybe the vegetables grown in the hydroponic system will have a softer taste. Some people like it, but some people say it’s unnatural. Humans are the only animals that wear clothes, but we don’t feel unnatural when we wear clothes, so don’t use the word natural. Zoom in infinitely.

The plant factory speaks with data. We adjust the light to grow ingredients that are beneficial to people. The ratio of blue light to red light in sunlight is fixed, but lighting can make the ingredients we need appear more, but it does not change the vegetables. Genes, this is the ability of the plant itself, we have not changed the genes of the plant.

Nutrients are the terminal application of vegetables, some have higher nutritional value, and some are not what we need. When we need a certain component of a plant, we can adjust it through physical conditions. This is the benefit of a plant factory. The growth of beneficial ingredients in the human body, or by changing the growing environment of vegetables to adjust different tastes.

5. What do you think about growing cannabis is illegal in China, but legal in the Netherlands? How is marijuana cultivation going?

Chen Guangcai: Marijuana itself is a double-edged sword, and its medicinal value is beyond doubt. Different states in the United States have different laws, depending on how the local government views this matter. At present, if you want to grow cannabis in China, you must have some special licenses, or you can only grow it in some special places.

Liu Yang: Many states in the United States have legalized the marijuana market, and mature lamps are now in use. And they are now looking for a more efficient LED lighting solution than high-pressure sodium lamps in the market. If your LED lighting solution has no obvious advantages over the current high-pressure sodium lamps, there will definitely be some obstacles to promotion.

6. What are the advantages and disadvantages of LED and traditional light source metal halide lamps (HID) in horticultural lighting? What is the development trend of ceramic lamps in the domestic and foreign plant lighting market?

Lei Ting: High-pressure sodium lamps have been used in agricultural production for a long time, and LEDs have just begun to be used. However, as general lighting, the current market share of LEDs is getting higher and higher, and many traditional lamps have been replaced by LEDs. This is the inevitable development of science and technology. trend. However, the spectral output of metal halide lamps is relatively fixed, and it is difficult to control the change of the spectrum, so it is suitable for the growth of some specific plants. At present, metal halide lamps are widely used in tomato planting, but if they are used in plant factories, LEDs are better than it. Much more, its spectrum fits better. However, the current QE value of LEDs has no obvious advantage compared with metal halide lamps.

Fang Wei: HID is difficult to apply to vertical farms. One is its heat and the other is its volume. In the greenhouse, it is also difficult for HID to compete with high-pressure sodium lamps, because the tendency of the spectrum is not the same. The artificial fill light in greenhouses all over the world is basically high-pressure sodium lamps. The Dutch people who used LEDs in greenhouses in the early days wanted to replace high-pressure sodium lamps. However, it was found that it was not feasible. The high pressure sodium lamps are installed in the greenhouse very high, about 4 or 5 meters high. One lamp covers a large area of ​​plants below. If the LED is installed at this height, the light will be much less, so currently the Netherlands uses a combination of the two. The headlights use high pressure sodium lamps, and the height-adjustable LEDs are used at a distance of 15 or 20 cm between the plants and the plants, specifically to illuminate the leaves above the results. The combination of the two is very good, and the LEDs basically only need red light. .

7. What is the difference between hydroponic vegetables and plant factories? Will there be insects growing in the vegetables in plant factories?

Jiang Jingjing: Whether it is a greenhouse or an indoor fully artificial light factory, insects will grow. The key is how to control it. The greenhouse is a semi-manually controlled environment. If the opening and closing state of the door is not well managed, insects will come in, usually in a large space. The strict conditions of plant factory management and greenhouse management are not the same level. When we enter the plant factory, human hair must be protected. In addition, the air and water of the plant factory are purified or filtered. If the management model of the plant factory is strictly followed, The probability of infestation is very low, so pesticides are not allowed in plant factories. In the greenhouse, we can only try to reduce its pollution ratio. Hydroponics through nutrient solution is one of the methods.

On the basis of different light qualities, how to ensure its luminous flux density? Also, how to make sure it's in the same light intensity. For example, the red and blue light sources are combined into the same power, and the blue light chip and the red light chip voltage chip are not the same. The different numbers seem to represent different light intensities, that is, the PPF is different, because the luminous flux is different from the plant chlorophyll. A and B are related.

Chen Guangcai: Even if it is the same PPF, each watt is similar to the concept of light effect, and different spectrums have different effects on plant growth. Many lamps on the market now measure performance in terms of PPF per watt. I I feel this is incomplete because it doesn't include the spectrum. Effective PPF is very important for plant growth spectrum.

We all know that in the design of lamps, it is difficult to achieve complete uniformity of the light spot illuminated by any lamp. It can only be achieved through optical design in the stage of lamp production, and the light should be made as uniform as possible. Some linear lights of the power do a good job, if you want to fill in the light in a greenhouse, you need a more precise optical design.

8. When conducting horticultural lighting studies, will light tests performed under the same PPFD and those performed under different PPFDs lead to different final test results?

Fang Wei: If the PPFD is the same, the spectrum is compared. If the PPFD is high or low, and the spectrum is different, the research results are basically unconvincing. However, it depends on the research direction. If the PPFD is the same, but the spectrum is different, this is the research on the spectrum; there are also studies that the PPFD is different, but the energy consumption is the same, and the same lamp is used normally, such as each 20-watt lamp. Lighting up 5 roots, through the adjustment of the placement height, the difference in cultivation intensity is compared, and these should be considered together as a whole.

I think there are several indicators that can be used to measure the overall efficiency of the plant factory. The first is to measure the light after the lamp is installed. The indicator of volume and the indicator of PPFD divided by watts are indicators of the light source itself. How many photons are generated by the power consumption of the light source, the PPFD of the cultivation surface needs to be measured, and the PPFD unit is used as an indicator to measure the condition after installation.

There is also an indicator called electricity production capacity. From vegetable sowing and germination to planting finished products, the total vegetable planting volume is divided by the electricity consumption. This indicator can measure the energy production capacity, that is, how many vegetables are grown per kWh of electricity.

The last indicator is the production capacity of photons. By looking at the growth performance of plants with the same number of photons in different spectra, you can immediately judge the pros and cons.