The Application and Development of LED in Plant Factories

  In recent years, LEDs have garnered extensive attention from scholars and users in the field of plant factories both domestically and abroad due to their numerous advantages. As the price of LEDs continues to decline, an increasing number of plant factories are choosing LEDs as artificial light sources.

  Since 1994, Japan has been trialing the use of LEDs as lighting sources in plant factories. Professors Masaki Taka - tsuji from Tokai University and Masanobu Nakayama from Osaka University in Japan successfully cultivated lettuce and rice in an artificial plant factory using a combined light source of 660 nm red LEDs and 5% blue LEDs. In 1997, Hiroyuki Watanabe used a water - cooled LED light source to grow vegetables in a plant factory. The cultivation method was the Nutrient Film Technique (NFT), and crops such as lettuce and celery were selected. The vegetables could be harvested two weeks after transplanting. On a cultivation area of 800 m² (8m×10m×10 layers), 5,900 vegetables were produced daily, with an annual output of 1.5 million vegetables.

  In February 2009, the Japanese company Fairy Angel announced that it had started collaborating with CCS, an LED lighting manufacturer, to develop the "Angel Farm Fukui" vegetable factory using LED lighting and hoped to promote it in Japan after achieving good results. In recent years, the development of LED plant factories in Europe and the United States has been extremely rapid. For example, in Newark, New Jersey, USA, [specific information is missing]. In February 2017, the Dutch Staay Food Group built a nine - story plant factory and used LED plant lighting to grow high - quality, pesticide - free fresh lettuce for supply to supermarket chains. Dubai is about to complete the world's largest LED vertical farm, which will cover an area of 18.11 mu (1 mu≈666.67 m²) after completion and is expected to produce 2,700 kg of high - quality, herbicide - and pesticide - free leafy vegetables daily. Currently, some well - known international companies such as Philips, Osram, Samsung, and GE are also actively engaged in the research and development of LED light sources for plants, aiming to develop dedicated LEDs for high - quality artificial - light plant factories.

  In China, the application of LEDs in plant factories began in 2006. In March 2006, the Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, built a small 20 m² artificial - light plant factory. Half of the light source system used LEDs and the other half used fluorescent lamps, and it was equipped with an environmental control and hydroponic cultivation system. The indoor environmental factors and nutrient solution were automatically detected and controlled by a computer. This was China's first experimental system for an artificial - light plant factory and also the first plant production system to use LEDs as artificial light sources. In 2009, the institute built a 100 m² LED intelligent plant factory  experimental system. More than 10 doctoral and master's students successively conducted experimental research on artificial - light leafy vegetable cultivation, seedling raising, and the cultivation of medicinal plants, obtaining a large number of original data, which laid the foundation for the application of plant factories in China. Subsequently, the institute successively established plant factories of varying sizes using LEDs as artificial light sources in Shouguang, Shandong, Beijing, Zhuhai, Guangdong, Nanjing, Jiangsu, Hangzhou, Zhejiang, and other places, greatly advancing the application of LEDs in plant factories.