Writer：Jane Time：2018-06-04 Browse：126
After years of exploration and development, China's closed plant factories have made rapid progress in materials, equipment and technology, and the production output has increased several times. With the continuous improvement and improvement of plant factory technology, even miniaturization and miniaturization plant factories have been applied to a variety of environments in people's lives, plant factories have been everywhere.
1. Classification of enclosed plant plant facilities
(1)Idle factories and basements
At present, almost everywhere there are vacant houses, factories, parking lots and basements, plant plants are the best choice to use these unused resources and create higher value. Transforming these idle land resources into closed plant factories to produce plants with high yield, high quality and high efficiency can not only revitalize idle resources but also reduce costs and create high value. It can be said that we can kill multiple birds with one stone.
(2) Used containers
Every year, a large number of containers are eliminated and abandoned in China. It is also a new measure to improve the utilization of resources to transform these old containers into artificial light closed plant factories. Containers have a variety of different specifications, the length of the general 5 ~ 12 m, the height and width are almost the same, generally in 2 ~ 3 m. The artificial light closed plant factory reconstructed from waste containers has the characteristics of good sealing, high safety, landscape, integrity, good structure, convenient temperature control, convenient movement, long service life and strong environmental adaptability. A single box can be an independent plant factory, multiple can also form a large plant factory, multiple stack can form a high-rise plant factory.
(3)Foam board house
Artificial light plant factory built with foam sandwich board has the advantages of light material, low cost, short construction period, good closure, etc. It can also be large, small, high and low freely, which is convenient for the construction planning of internal facilities, and is widely favored by plant plant factory builders.
(4) Inflatable membrane
The aerated film is a fully enclosed structural space formed by filling the air with high polymer materials (high strength carbon fiber and aerogel film products). The high-level three-dimensional plant cultivation system constructed in such structural space is called aerated film enclosed plant factory. This kind of inflatable membrane is an important branch of membrane light space structure, with a variety of colorful shapes, can be built to cover an area of more than 20 hm2, the height of more than 40 m of the giant inflatable membrane greenhouse, has excellent architectural characteristics, structural characteristics and suitable economy. The aerated membrane structure is a relatively closed space structure, different from the traditional space structure, it through the fan to the structure of the internal air supply, so that the membrane structure inside and outside to maintain a certain pressure difference, to ensure the stiffness of the membrane structure system and maintain the design of the shape.
The inflatable film has rich and colorful shape, and the inflatable house is designed into the shape of the inflatable film. Made of high-strength carbon fiber, aerogel film and air, the inflatable house is powered by solar energy on the outside, information intelligence and plant plant systems on the inside, and air in the middle. This kind of inflatable house closed plant factory has the advantages of low cost, strong sealing, good integrity and convenient use.
(5)Space airtight film
Over the years, in the former Soviet union "salute" and "peace" space station, plant cultivation and many times of food crops to produce long-term experiment, from cultivating chlorella algae such as experiment to all kinds of flowers, vegetables and crops, let the plants in the whole process of space has experienced from sowing to harvesting, and has made a breakthrough; Hundreds of plants have been cultivated on board the Mir space station and food crops such as wheat have been successfully grown.
China has also successfully experimented with growing plants in the fully enclosed Tiangong-1. Chinese scientist Zhang Mao has obtained the invention patent of "space Rubik's Cube inflatable dwelling house". This space cabin wall shell consists of one or more layers of high-strength air-tight film similar to spacesuit material. The air-tight film has two kinds of opaque or transparent, which can make several cabins firmly connected to each other and maintain a fully closed air-tight state. It is filled with nitrogen, and compared with the gold space vehicle, it has the characteristics of light weight, low cost, high safety, good temperature resistance and strong compression resistance. It is the future development and utilization of space resources, the construction of space plant factories, become the important equipment and facilities of life support system.
2. the selection of plant cultivation forms of closed plants in factories
Closed plant factory can be divided into planar multi-layer stereoscopic culture, polyhedral stereoscopic culture, hanging stereoscopic culture, curtain wall stereoscopic culture, cylindrical stereoscopic culture and other forms.
(1)Plane multi-layer stereoscopic culture
At present, the vast majority of closed plant factories in Israel, the United States, Japan and other countries including China generally adopt planar multi-layer stereoscopic cultivation. This form of cultivation is commonly used in plant factories on non-agricultural land, such as old factories, vacant houses, basements, etc.
Within the container closed plant factory, only the design frame, two rows of cultivation due to height and space constraints, cultivation form can only be 3 ~ 4 layers, it is because the plane multi-layered solid cultivation form only using hydroponic nutrient technology, each layer should be nutrition pool, cultivation board, LED lighting lamp and vegetable plants as well as the cultivation of the space, In general, each layer is 65 ~ 70 cm in length, so that the space for expanding the cultivation area is limited, resulting in the yield and benefit can only be improved within a certain range.
In other type of factories closed plants, according to the height of its facilities and space, the plane layers to the space outspread more layers, so far, the closed plant factory of zhejiang university in China has reached 10 layer, the world's largest plant factory 2300 m2 of artificial light LED Japan has been increased to 15 layers, output and efficiency are improved more.
(2) Polyhedral stereoscopic culture
Polyhedral stereoculture is an innovative cultivation form in China, which is also produced in closed plant factories such as empty houses, factories, basements and centralized boxes. Compared with planar multi-layer cultivation, its effect has obvious advantages.
Container factory closed plants, for example, you can set the cultivation bed in both groups, each group of cultivation on both sides of the bed can be cultivated plants, two sets of bed with a total of four plant cultivation, this kind of polyhedron stereoscopic cultivation bed form fog culture technology can be used instead of nutrient solution a hydroponic technology, each group of cultivation bed only one nutrient pool, leds can be configured in the middle of the container around two walls and the aisle, So light, water, fertilizer, higher space utilization, due to implement the fill with water, fertilizer, gas, make the plants grow faster, cheaper, lighter, and yields a lot of times, if the enclosed inflatable membrane used in a plant factory polyhedron cultivation form production plants, more stereo space, to maximize yield and economic benefits.
(3)Curtain wall stereoscopic culture
Curtain wall stereoculture is to cultivate plants on the walls of closed plant factories or the curtain walls of artificial design and construction. Container type plant factories, for example, box around the container walls set up cultivation bed, tidal creek culture technology is adopted in the cultivation bed cultivated plants, cultivation bed sets nutrition pool, fill the container top mounted LED light, compared with the surface layers of solid cultivation, this kind of light use more fully, layout reasonable, operation more convenient, cultivation face bigger and higher yield. If more, higher and wider plant curtain walls are set in the closed aerated film plant factory to cultivate plants, the output and benefit will be higher.
(4) Vertical stereoscopic culture
It is not only a kind of agricultural production, but also a kind of survival art to hang the plant cultivation bed on the top of the closed plant factory, and then sow, irrigate, fertilize and plant protection on the cultivation bed. In any closed plant plant factory, the realization of vertical stereoscopic cultivation for agricultural production can not only expand the area, improve the yield, increase the benefit, but also reduce the cost, improve the utilization rate of resources, both ecological and environmental protection, and facilitate sustainable production; Not only easy to operate, but also enhance the life experience.
(5)Cylindrical stereoscopic culture
The plant is planted on the surface of the cylinder, the three-dimensional cultivation area is larger, and the aeroponics technology is adopted, the plant grows faster. However, in the enclosed container plant plant, because the environment space is too small, it is not suitable to use the cylindrical stereoscopic cultivation device. However, the advantages of cylindrical stereoculture in other types of closed plant plants, especially in aerated film and airtight film closed plant plants, will be more extended.
3.Selection and comparison of plant cultivation techniques in closed plant factories
(1) Cultivation forms and cultivation techniques
Closed plant factory cultivation techniques can be divided into substrate culture, nutrient solution hydroponics, tide stream culture and aeroponics. These cultivation techniques can be used alone or in combination, but they must be for the purpose of high yield and high quality. The choice of cultivation technique is determined by the cultivation form. Generally speaking, once the cultivation form is determined, the cultivation technique is also determined. Advanced cultivation forms and corresponding cultivation techniques determine the yield, quality and characteristics of enclosed plant factories.
(2) Comparison of main cultivation forms and techniques
Taking 40HQ container closed plant plant as an example, most plant plants in China adopt the Japanese plane-multi-layer stereoscopic culture form and the corresponding nutrient hydroponics technology. Type 40HQ container is 12 m long, 2.35 m wide and 2.39 m high, with a space area of 67.398 m2.
For planar multi-layer stereo-cultivation, one row of 12 m long cultivation racks can be set up in the cultivation areas on both sides of the middle passage, and three layers of 60 cm wide cultivation beds can be set up on the shelves. In this way, the actual planting area of the whole 40HQ container space is 43 m2. If 12 vegetables can be planted per square meter, and 518 plants can be planted in each batch, A total of 5 180 plants could be planted in 10 batches throughout the year.
In the case of polyhedral stereoculture, one planting bed can be built on both sides of the middle corridor, each planting bed is 12 m long and 2 m wide, and each bed surface can be planted with an area of 24 m2. In this way, a total of four planting areas can be built, that is, the actual cultivation area is 96 m2, and 11 520 plants of vegetables can be planted in the whole year.
In this way, when the vegetables are cultivated in the same container and the same amount is planted in the same area, because the two cultivation forms are different, there will be two results accordingly. Compared with the planar multi-layer stereoscopic culture, the actual cultivation area and number of polyhedral stereoscopic culture are increased by 2.2 times. In addition, due to the use of nutrient liquid hydroponics in the form of planar multi-layer stereoscopic culture, and the use of aeroponics in polyhedral stereoscopic culture, the advantages of polyhedral stereoscopic culture are also shown in the following aspects:
(1) Nutrient solution hydroponic technology can only achieve water and fertilizer for plants, but aeroponic technology truly realizes water, fertilizer and gas for plants, so that plants grow faster, which is incomparable to any kind of cultivation technology;
(2) In terms of the utilization rate of water and fertilizer resources, the aeroponic technology has realized the recycling utilization, which is 1/10 of the water consumption of nutrient hydroponic technology. The utilization rate of fertilizer in nutrient hydroponic technology is 60% ~ 70%, while the utilization rate of fertilizer in aeroponic technology reaches more than 95%, truly realizing zero pollution and zero emission.
(3) the nutrient solution a hydroponic technology in high temperature season, once the nutrient solution temperature is above 35 ℃, the plant will stop growing and die from the wilting, in low temperature season, once the temperature is lower than the lower limit value 0 ℃, most plants will stop growing and even suffer from cold, the fog culture technology under the same conditions, the temperature control measures of costs are much lower.
There are many forms of stereoscopic cultivation and a variety of cultivation techniques to choose from. In actual production practice, different cultivation forms and corresponding cultivation techniques should be selected according to different plant varieties, and various factors such as yield, ecology, cost, landscape, quality and maneuverability should be comprehensively considered to make scientific selection for the best.
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