A detailed explanation of the past, present and future of the LED plant factory

LED Lighting Reuters the past decade, due to blue LED occurs with the red and blue LED successful development of combination light source, and the application, artificial light energy plant factory-based intelligent network control technology has been significantly reduced, the cultivation layer The spacing is further shortened and the energy efficiency ratio is greatly improved. At the same time, the application of sensors, intelligent controllers and IoT technology has also made it possible for plant factories to intelligently control.

We can see that during this period, many countries across the country have accelerated the pace of research and development and industrialization of plant factories. For example, since 2009, Japan has proposed vigorously developing plant factories and revitalizing modern agriculture programs. In the same year, the Korean government also began to support research institutions and companies to jointly develop artificial photoplant factories. On the one hand, the United States provides food security for space stations and planetary exploration through the research of plant factories. On the other hand, it proposes the concept of “skyscraper agriculture” and wants to break through the resource bottleneck from space...

Also in 2009, the R&D team of the Plant Research Institute of China Academy of Agricultural Sciences and the Beijing Zhonghuan Yanda Facility Horticultural Technology Co., Ltd. developed the first intelligent plant factory in China. At present, the technical achievements have been extended to more than 20 provinces, autonomous regions and municipalities such as Beijing, Shanghai and Shandong.

In fact, China has started research and development of plant factories since the 1990s. In 2002, it successfully developed natural light plant factories. In 2005, it developed the LED plant factory experimental system, and exhibited the home LED plant factory for the first time at the 2010 Shanghai World Expo. In 2013, the state officially listed the “Intelligent Plant Factory Production Technology Research” project in the “863” program, and currently has about 100 artificial light plant factories of different scales.

The growing momentum of plant factories has gradually attracted the attention of many people in the LED lighting industry. In addition, this year’s President Xi Jinping visited the national “12th Five-Year” Science and Technology Innovation Achievement Exhibition and independently developed intelligent LED plants for the Chinese Academy of Agricultural Sciences. The factory has shown a certain degree of attention, especially for those who are interested in joining the industry, and they have added a lot of confidence to their future development.

In this article, Liu Wenke, a researcher, doctoral and doctoral supervisor of the Institute of Agricultural Environment and Sustainable Development of the Chinese Academy of Agricultural Sciences, will explain the plant factory in many aspects, or help people to understand more about the development status of this field. With the prospects.

Definition

According to the Japanese scholar Gu Shi’s “Artificial Light Plant Factory” and the Chinese scholar Yang Qichang’s “Introduction to Plant Factory”, the plant factory definition is: the plant factory is a kind of high-precision environment control in the facility to realize the crop anniversary. The high-efficiency agricultural system that is continuously produced is the temperature, humidity, light, and CO of the crop growth process by the computer. The environmental factors such as concentration and nutrient solution are automatically controlled, and labor-saving production methods that are not subject to or are rarely restricted by natural conditions.

The plant factory makes full use of modern equipment engineering, biotechnology, facility horticulture technology, plant physiology, plant cultivation engineering and environmental control information technology. It is a highly technically intensive industry and has been recognized as the most advanced development of facility horticulture for many years. The stage is one of the important indicators to measure the level of high-tech development in a country's agriculture.

However, Dr. Liu Wenke said that the concept of plant factories originating from Japanese scholars has certain deficiencies, mainly because the definitions are too general and the boundary conditions are relatively vague. It does not involve the type of facilities, facility tightness and control factors and their precision. difference. This hinders people's unified understanding of plant factories and confuses the direction of system technology research and development and industrial application. Plant factories should have the basic attributes of a "factory." Closed plant production systems and automation are core indicators for measuring plant plant modernization and factory production potential.

From the perspective of definitional generality and authority, plant factory environmental control essentially includes three categories: water and fertilizer automation control, environmental factor automation control, and plant product production line automation platform.

The plant factory should be a streamlined plant production facility with a certain degree of automation. The automated assembly line is divided into three stages: prenatal (nurturing), mid-production (transplantation, cultivation and transportation), post-production (harvesting, packaging), with emphasis on the prenatal and mid-production phases.

The essential feature of plant factories is the automatic control of production factors, but the level of automation of plant factories is hierarchical, and the level of intelligent facilities is divided. The recommended definition of a plant factory should focus on the essential characteristics of automation control within its facility. Dr. Liu Wenke pointed out that the previous definition focused on the highest stage and ideal form of the plant factory, ignoring the various forms of plant plant development process, it is difficult to cover the transition patterns of all current plant factories, and it is recommended to make corrections.

To this end, he suggested that plant factories should refer to some or all of the production factors (environmental factors, water and fertilizer supply, etc.) directly related to plant growth and development, which can be automatically regulated and controlled, and have certain spatial automatic management functions of plant production processes. Plant scale production system with high efficiency and low or no external environment interference. Based on this definition, the facility model in the form of a solar greenhouse and a multi-storey building can be regarded as a plant factory as long as it has defined essential characteristics.

Technical articles

According to reports, the core technical equipment of the plant factory includes four aspects, namely, three-dimensional multi-layer soilless cultivation technology equipment, artificial light lighting technology equipment, intelligent environmental control technology equipment, and plant production space automation control technology equipment.

In recent years, these core technical equipments have been greatly developed and are being gradually standardized and applied on a large scale. The plant exterior structure design, functional partitioning, and regional containment guarantees are all important, directly related to plant plant initial installation costs and operating costs and energy consumption, as well as production efficiency.

1. Three-dimensional multi-layer soilless cultivation technology and equipment

The three-dimensional multi-layer soilless cultivation technical equipment refers to the technical equipment for realizing the production of plants on the multi-layer three-dimensional cultivation frame by using the soilless cultivation method and the equipment of the cultivation bed and the layered pipeline. The three-dimensional multi-layer soilless cultivation technology equipment is the essential essential equipment of the artificial light plant factory, and it is also the technical equipment that the solar plant factory needs to develop urgently. At present, a variety of three-dimensional multi-layer soilless cultivation technology equipment based on NFT and DFT technology has been developed, which is suitable for the production of leafy vegetables and rhizome plants. The three-dimensional multi-layer soilless cultivation technical equipment mainly includes a nutrient liquid storage and supply system (nutrient liquid pool, pumping system, liquid supply liquid returning pipeline, planting bed, control system, etc.).

2, artificial light lighting technology and equipment

Artificial light lighting technology equipment is the core technology equipment of artificial light plant factory, providing photosynthetic energy and illumination signals for plant production. Fluorescent lamps are traditional light sources and LEDs are new sources of light. The plant physiological response mechanisms of the two light sources have been widely revealed, and the biological basis of the application of the two light sources has been very clear. However, LED as a new solid-state semiconductor light source has the optical advantages that fluorescent lamps cannot match, including:

(1) The spectrum can be modulated according to the growth and development requirements of the plant, and the light is used as needed, and the biological light effect is high;

(2) Cold light source, which can be close to plant irradiation and improve space utilization;

(3) Good controllability, precise control of light intensity, light quality and photoperiod, etc., suitable for factory production;

(4) Energy saving, environmental protection, long life, small size and light weight;

(5) A variety of LED light source devices (light panels, strips, tubes and bulbs), suitable for all areas of facility gardening.

At present, plant factory lamps such as panel lights, strip lights, lamps, and lamp strips have been developed and promoted. At the same time, a variety of LED fill light lamps have been developed in the Sunlight Plant Factory, including inter-row canopy fill lamps, flowering lights, and strip lights. Artificial light lighting technology equipment mainly includes light source lamps, suspension systems, control systems, power supplies and so on.

3. Intelligent environment control technology and equipment

Intelligent environmental control technology equipment consists of an actuator, a detection mechanism, and a control mechanism. The control factors include temperature, humidity, illumination, and CO. A variety of production factors such as concentration, airflow, and nutrient solution supply, to a large extent, the level of environmental control intelligence determines the operational efficiency of plant factories. The intelligent environment control is based on the control of plant environment, and it is especially necessary to use the physiological response effect of plants under the coupling of environmental factors as the basis, and further systematic research is needed. Among the environmental control elements, the most important are nutrients and light. Nutrient and illumination are two environmental factors that have both quantitative and qualitative attributes. Intelligent control is difficult. The control strategy has time and space requirements. It also needs to be coordinated with other environmental factors. It is the focus of future research and development. .

4. Plant production space automation control technology equipment

Plant production space automation management and control technology equipment includes plant transplanting and planting technology and equipment, plant space horizontal vertical mobile transmission technology equipment, horizontal and vertical mobile transmission equipment for light source lamps, as well as mechanized automatic lifts, automatic harvesting and other production management technical equipment. The plant production space automation control technology and equipment is the main equipment of the plant factory assembly line operation, which is conducive to improving production efficiency and control level.

History

It is understood that the development of plant factories began in the 1950s in some developed countries such as Europe and the United States. After more than half a century of development, it has become an important part of the modern agricultural high-tech industry.

The foundation of the plant factory is mainly from the breakthrough of two technologies:

(1) Nutritional liquid cultivation techniques. Since the 1940s, the plant nutrition and fertilizer industries based on the theory of “mineral nutrition theory” have developed rapidly. The water-soluble fertilizers have been developed according to the fertilizer formula. An important technical support.

(2) Environmental awareness and control technology. Breakthroughs in environmental control technologies centered on sensors and controllers have made it possible to control the artificial environment. Based on these two technologies, the plant factory has realized the annual continuous production of plants. After 2000, with the advancement of LED plant lighting technology, the LED light source plant factory came out, which has realized the intelligent light environment control technology of the plant factory, which greatly improved the automation level and energy saving efficiency of the plant factory.

At present, plant factories are mainly distributed in East Asia and Europe and the United States, with Japan, the Netherlands and China being the most representative.

There are several models for the development and industrialization of plant factories worldwide, including: enterprise-led, research institute-led, and government-led.

The application mode of plant factories in China includes: community mode, public place mode (hospital, shopping mall, restaurant, hotel, etc.), family mode, special place (island, desert), enterprise mode (lighting enterprise, agricultural enterprise, etc.).

The functions of plant factories include: plant product production, ecological landscape, popular science experience, scientific research, high-tech display, etc. The existing mainstream models are scientific research and commercial production.

The future industrial model of the plant factory will be a variety of innovative models established and operated by the government, enterprises, research institutes and user companies.

Roughly estimated, the global plant factory market has a total scale of more than tens of billions of yuan, and the plant factory market in China is over 100 billion yuan. After 2000, China's plant factory industry flourished. In the first half of 2016 alone, there were more than 20 artificial light plant factories in operation, and thousands of hectares of solar plant factories.

However, the scale of China's plant factories is small (more than 200m2), the production of plants is single (leaf-leaf-based), the level of environmental control technology and equipment is uneven, and the demonstration and research plant factories are mostly commercial plants. Less, it is urgent to push forward. After the plant production technology and equipment are matured, efficient production can be realized and become the basis for profitable operations.

The connotation of the profitable business model of the plant factory: First, we must explore and maximize the profit points of the plant factory's main plant products, product audience, sales methods, price advantages, etc. Secondly, diversify the plant factory's profit path and widely receive social support. .

The vast majority of plant factories in the world are built in cities and are an important part of urban agriculture. The world's major plant factories are striving to develop overseas markets and exporting technical equipment. It is expected that competition will intensify.

Question

Problems facing the development of plant factories

The plant factory is the trend of future facilities horticulture development, an important goal of modern agricultural development, and has a broad market prospect. Moreover, plant factories are ubiquitous in application and have a wide range of application functions, and the penetration rate has increased significantly in recent years. It is true that the current development of plant factories is also facing many problems, which need to be taken seriously and solved one by one.

First of all, plant plants are expensive to install. The initial installation cost of plant factories is much higher than that of solar greenhouses and multi-span greenhouses, generally above 6,000 yuan/m2, and a 100m2 artificial light plant factory has an initial installation cost of more than 600,000 yuan.

Second, plant plants have high cost of plant products. Taking lettuce as an example, the artificial light plant factory produces vegetables at a cost of 10 to 30 yuan, and has a small profit margin under the decision mechanism of the vegetable price market in China.

Third, plant factories have higher operating costs and high energy and labor costs. On the one hand, plant plant light source, environmental control system operation (air conditioning, airflow, nutrient solution supply, etc.) all need to consume electrical energy, and the energy consumption is high; on the other hand, the degree of automation is low, and the cost of transplanting, planting, and harvesting labor is high.

Fourth, the degree of standardization is low and there is no government subsidy policy. Finally, the commercialization model is maturing, but the profitability needs to be further explored. Profitability is the ultimate driving force for industrial development. Efforts should be made to tap the profitable way of commercial application of plant factories in line with market demand.

In general, the profitability of plant factories is not only related to their own production capacity, but also related to social background, industry development level, and national policies. It is a systematic social practice.

Countermeasures for the development of plant factories

The plant factory industry is an emerging industry. It requires systematic research on technical equipment and operational strategies, and explores new operating models and profitable ways to achieve sustainable development. In the face of current problems, the development strategies of plant factories are summarized as follows:

(1) Research and development of energy-efficient plant production technology and equipment to achieve high quality and high yield. The high-quality and high-yield production of agricultural production systems is the basis for the profitable development of plant factories. The continuous and stable production of high-quality, high-commercial plant products by plant factories must overcome the corresponding key technologies. Efforts should be made to develop high-efficiency three-dimensional multi-layer soilless cultivation technology equipment, artificial light lighting technology equipment, intelligent environmental control technology equipment, plant production space automation control technology and equipment at the core technology level of plant factories, and to introduce an optimized combination and integration system. Among them, intelligent environmental control technology and equipment are more important, which is directly related to the growth factors such as plant growth and development, yield quality and plant plant energy consumption.

(2) Develop technical parameters of factory production of high value-added plants to improve profitability. Accelerate the study of plant photobiobiology of high value-added plants (medicinal plants, health plants, rare vegetables, etc.), expand the plant species produced by plant factories, and explore the environmental regulation mechanisms of anabolic accumulation of functional active substances, increase The amount of site biomass and beneficial compounds can be used.

(3) Establish a brand strategy to accelerate the social recognition and recognition of agricultural products and technical equipment in plant factories. Focus on the development of plant plant plant product brand, consolidate the quality assurance mechanism, increase brand promotion, and make plant factory products deep into the hearts of the people, thereby increasing sales and output value.

(4) Build a variety of plant types and products, and expand the profit model. We will focus on the development of plant-type, commercial, and community-based plant types, enrich the commercialization of plant factories, expand the purchase of people, increase the types of plants produced in plant factories, and make full use of the multiple functions of plant factories to achieve sustainable profitability.