Analysis of LED light source application in agriculture
(1) Application of LED light source in agriculture. China is the production base and export base for planting plant seedlings in the world. It is also the world's largest market for tissue culture seedlings. Since the mid-1990s, China has undertaken the industrial transfer of the global factory group to cultivate seedlings, and the process of industrial transfer has now been completed. According to statistics from the Ministry of Agriculture, by the end of 2007, there were more than 300 tissue culture enterprises with an annual output of more than 10 million plants. The total area of plant tissue culture was over 20 million square meters, and the annual output value was about 20 billion yuan. In addition, plant factories, especially artificial light plant factories, also have a huge demand for LED light sources. At present, commercial plant factories are mainly distributed in Japan, with a total of 50 plants, 35 of which are completely artificial light. With the growing maturity of plant factories, plant factory applications will also be an important LED application. market.
(2) Compared with traditional light source LEDs, the advantages in agricultural lighting are obvious. LED has many advantages such as high light efficiency, low heat generation, small size and long life.
a, bio-energy efficiency. Studies have shown that plant photosynthesis mainly uses red orange light with a wavelength of 610~720nm (wave peak is 660nm), and the absorbed light energy accounts for about 55% of its physiological radiation; secondly, the wavelength is 400~510nm (wave peak is 450nm). The blue-violet light absorbs about 8% of its physiological radiation. By using LED as a plant light source, the radiation spectrum can be controlled to be red and blue, and the red and blue light ratio can be precisely adjusted according to the different needs of different plants, so that the radiant energy can be fully absorbed and utilized by plants, compared with traditional light sources. Greatly improved its bio-energy efficiency.
b. On the one hand, because the LED light source is compact, its volume is greatly reduced compared to the conventional light source; on the other hand, since the conventional light source radiates a large amount of heat to the surface of the plant, it must be maintained when it is used as a plant fill light source. The plant and the plant indicate a certain interval. For example, when the high-pressure sodium lamp is used, it is generally required to be at least 1 m apart from the plant, and the LED is a cold light source, and the radiation effect of the radiation spectrum on the plant is much smaller than that of the conventional light source, even if it is irradiated at a close distance. It causes plant burns, so it can achieve close-range irradiation of plants. In this way, the distance between the cultivation shelf can be greatly shortened in the plant factory or tissue culture, the space utilization efficiency can be improved, and the planting density of the plant can be greatly improved.
c. According to statistics, in the production of fluorescent lamp tissue culture, lighting energy consumption accounts for 30% to 40% of the operating energy consumption, while in the fluorescent plant planting plant, this share is as high as 82%. The use of LEDs instead of traditional lighting sources can greatly reduce the lighting energy consumption of these agricultural productions. For example, the Netherlands's use of LED light-filling experiments in greenhouses shows that LEDs can save 50% to 80% compared with traditional high-pressure sodium lamps and metal halide lamps; in plant factories, traditional light sources need to be equipped with 0. 5 square meters. The kilowatt light source, while the LED only needs 0. 27 kW, so that the power consumption can be reduced by about half. In the field of tissue culture, the total area of tissue culture in the whole country is more than 20 million m2. If the daily light time per day is 16h/d and the production day is 300 days per year, the total annual electricity consumption caused by fluorescent lamps is 107.5 billion kW & middot; h or more; after using LED, its annual power consumption is about 51.8 billion kW & middot; h, the annual total electricity saving is above 56 billion kW & middot; h, the energy saving effect is remarkable.
LED is considered to be the most promising artificial light source in the 21st world agricultural field. It is of great significance to solve environmental pollution, improve space utilization and reduce greenhouse effect. LED energy-saving light source should be very extensive and practical in the agricultural field.