JP2021171031A - Plant growing method and plant growing device - Google Patents

Abstract

To provide a plant growing method and a plant growing device, which are capable of irradiating a plant with artificial light to control the growth of the plant and the color of the plant.SOLUTION: A method for growing plants comprises: a first step of irradiating the plant with red light as the main irradiation light during the first period from planting, of the entire growing period of the plant from planting to harvesting; and a second step of irradiating the plant with blue light as the main irradiation light during the third period from the end of the second period following the first period to the harvesting, of the entire growing period.SELECTED DRAWING: Figure 2

Description

The present invention relates to a plant growing method and a plant growing device, and more particularly to a plant growing method and a plant growing device obtained by irradiating a plant with artificial light to control the growth (growth) and color of the plant.

In order to supply fresh, safe and secure agricultural products, facility gardening using glass rooms and greenhouses has been practiced. In recent years, in order to supply agricultural products more stably, plant cultivation by plant factories has also been carried out.
In such facility gardening and plant growing by a plant factory, a technique of irradiating the grown plant with artificial light is adopted.

Patent Document 1 discloses a method of changing the wavelength of artificial light according to the growth stage of a plant (plant seedling). This technique is a technique of irradiating blue light in the initial growth stage of a plant and irradiating red light in the later stage of the growth stage. In Patent Document 1, it is proposed that the growth control of plants and the control of morphological aspects (leaf area, stem length, etc.) can be realized by the above-mentioned light irradiation method.

Further, Patent Document 2 proposes a method of alternately irradiating red light and blue light in a light irradiation step of a plant. In Patent Document 2, it is proposed that a plant cultivation effect such as an excellent growth promoting effect can be obtained by the above-mentioned light irradiation method.

Special Table 2016-518146 Gazette Japanese Unexamined Patent Publication No. 2015-142585

Conventionally, artificial light has been applied to a plant for the purpose of controlling the growth of the plant (promotion of growth, etc.) and morphological aspects (leaf area, stem length, etc.). However, controlling not only the degree of growth and shape of a plant but also the color of the plant has not been considered so far.

In the technique described in Patent Document 1, the wavelength of the artificial light to be irradiated is switched according to the growth stage of the plant. In other words, this technology is a technology that irradiates artificial light that has the property of efficiently growing plants at each growth stage of the plant, and does not consider controlling the color of the plant at all. ..
Further, the technique described in Patent Document 2 alternately irradiates red light and blue light regardless of the growth stage of the plant, and controls the color of the plant as in the technique described in Patent Document 1 above. No consideration is given to what to do.

An object of the present invention is to provide a plant growing method and a plant growing device capable of controlling the growth of a plant and controlling the color of the plant by irradiating the plant with artificial light.

In order to solve the above problems, one aspect of the plant growing method according to the present invention uses red light as the main irradiation light during the first period from the planting in the entire growing period of the plant from planting to harvesting. During the first step of irradiating the plant and the third period from the end of the second period following the first period to the harvesting of the entire growing period, the plant uses blue light as the main irradiation light. Includes a second step of irradiating the light.
In this way, the entire growing period is divided into three periods, in which the red light effective for plant growth is irradiated as the main irradiation light in the first first period, and the color of the plant is improved in the final third period. It irradiates blue light, which is effective for this purpose, as the main irradiation light. Therefore, it is possible to grow a large-grown plant with a good color.

Further, in the above-mentioned plant growing method, the first period may be a period from the planting to at least 1/3 of the total growing period in the total growing period.
Plants usually start to grow steadily after about 1/3 of the total growing period has passed since planting. Therefore, by irradiating red light, which is a light specialized for plant growth, with the period from planting until at least 1/3 of the total growth period elapses as the first period, the growth of the plant after planting is appropriate. Can be promoted to.

Further, in the above-mentioned plant growing method, the third period may be a period of at least 3 days before the harvesting in the total growing period.
As described above, by irradiating the plant with blue light with at least the last three days of the entire growing period as the third period, the color of the plant can be appropriately improved.

In addition, the above-mentioned plant growing method may further include a third step of irradiating the plant with red light as the main irradiation light during the second period.
In this case, the plant can grow more.

Further, in the above-mentioned plant growing method, the third step is a step of irradiating the plant with the irradiation light containing blue light during the second period, and in the third step, the second step. During the period, the intensity of the blue light may be gradually increased.
In this case, in the second period, not only the growth of the plant can be promoted, but also the color of the plant can be controlled. Further, by gradually increasing the intensity of the blue light added to the red light in the second period, it is possible to suppress the suppression of plant growth in the early stage of the second period.

Further, in the above-mentioned plant growing method, in the second step, the intensity of blue light contained in the irradiation light irradiating the plant in the third period is irradiated to the plant in the first period and the second period. The intensity of the blue light contained in the irradiation light may be increased.
In this case, it is possible to appropriately improve the color of the plant while suppressing the suppression of the elongation of the plant.

Furthermore, in the above-mentioned plant growing method, in the second step, the ratio of the intensity of blue light contained in the irradiation light irradiating the plant in the third period is set in the first period and the second period. It may be set to be larger than the ratio of the intensity of the blue light contained in the irradiation light applied to the plant.
In this case, it is possible to appropriately improve the color of the plant while suppressing the suppression of the elongation of the plant.

Further, in the above-mentioned plant growing method, in the second step, the plant may be irradiated with the irradiation light containing no red light during the third period. In this case, the third period can be a period specialized for color tint control, and the tint can be improved more appropriately.
Further, in the above-mentioned plant growing method, the plant may be a leafy plant. In this case, the color of leaves of leafy vegetables, for example, can be appropriately controlled.

Further, one aspect of the plant growing apparatus according to the present invention is a first light source that emits red light as a main emitted light, a second light source that emits blue light as a main emitted light, the first light source, and the second light source. A control unit that controls a light source to irradiate a plant with light is provided, and the control unit is provided with the first period during the first period from the planting during the entire growing period of the plant from planting to harvesting. The plant is irradiated with light emitted from a light source as irradiation light, and during the third period from the end of the second period following the first period to the harvesting of the entire growing period, the second period. The light emitted from the light source is used as irradiation light to irradiate the plant.
In this way, the entire growing period is divided into three periods, in which the red light effective for plant growth is irradiated as the main irradiation light in the first first period, and the color of the plant is improved in the final third period. It irradiates blue light, which is effective for this purpose, as the main irradiation light. Therefore, it is possible to grow a large-grown plant with a good color.

According to the present invention, it is possible to control the growth of a plant and the color of the plant by irradiating the plant with artificial light, and it is possible to grow a large-grown plant having a good color.

It is a figure which shows the relationship between the growth period and the growth degree of a plant. This is an example of an artificial light irradiation procedure. This is a comparative example of the artificial light irradiation procedure. It is a comparison result of the degree of color development of plants. This is another example of the procedure for irradiating artificial light. This is another example of the procedure for irradiating artificial light. This is another example of the procedure for irradiating artificial light. This is another example of the procedure for irradiating artificial light. This is a schematic configuration example of a plant growing device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In this embodiment, a plant growing method of irradiating artificial light during the growing period of the plant will be described.
In the present embodiment, the period from immediately after planting a plant seedling (immediately after planting) to harvesting a grown (growing) plant is defined as a "total growing period (total cultivation period)" of the plant.
Then, in the present embodiment, the entire growing period of the plant is divided into a "growth stage" and a subsequent "coloring stage", and in each stage, the wavelength of the artificial light irradiating the plant is adjusted to an appropriate wavelength. Then, the plant is irradiated with the artificial light.

[Growth period and color development period]
FIG. 1 is a diagram showing the relationship between the growing period of a plant and the degree of growth. Here, FIG. 1 shows the degree of growth when the leaf lettuce is grown by irradiating it with natural light. In FIG. 1, the degree of growth on the vertical axis is the leaf length of leaf lettuce, and the leaf length at the time of shipment (at the time of harvest) is standardized as 1. As shown in FIG. 1, the total growing period of leaf lettuce (the period from planting to harvesting) is 17 days, and leaf lettuce starts to grow steadily from about 6 days after planting.

Therefore, the present inventors have determined that the period from planting to the elapse of about one-third of the total growing period is a preferable period in which artificial light is irradiated specifically for plant growth.
Based on the above findings, in the present embodiment, the period from planting to at least one-third of the total growing period, the growing period for growing the plant, and the period from the end of the growing period to the harvest are used to develop the color of the plant. It is defined as the color development period to be caused.

Further, in the present embodiment, the color development period is further divided into two periods. That is, the entire growing period is divided into three periods consisting of a growth period and two coloring periods. Then, these three periods are designated as the first period, the second period, and the third period in chronological order.
Here, the first period is a period corresponding to the above-mentioned growth period. The second period is a period following the first period, and is a period during which the plant develops color while growing. The third period is a period from the end of the second period to the harvest, and is a period for developing the color of the plant. The third period shall be at least 3 days before harvesting out of the total growing period.

Then, in the present embodiment, the first period is a period for irradiating the plant with red light, the second period is a period for irradiating the plant with red light and blue light, and the third period is for irradiating the plant with blue light. The period.
In addition, "irradiating red light" in the first period means that the main wavelength band of the irradiation light is the wavelength band of red light, and "irradiating red light and blue light" in the second period. Means that the main wavelength band of the irradiation light is the wavelength band of the red light, and the irradiation light includes the blue light, and "irradiating the blue light" in the third period means that the main wavelength band of the irradiation light is It means that it is the wavelength band of blue light.

FIG. 2 is a diagram showing an example of an artificial light irradiation procedure in the plant growing method of the present embodiment.
[1st period]
The first period, which is the growth period, is a period in which the plant is grown (elongated) by irradiating it with artificial light.
The absorption peak wavelengths of chlorophyll (chlorophyll) required for plant photosynthesis are around 450 nm and around 660 nm.
In addition, among the photoreceptors of plants, phytochrome involved in photomorphogenesis is activated by red light having a wavelength of around 660 nm.
Therefore, it can be said that the red light containing the wavelength of 660 nm has an effect of particularly promoting the growth of plants.

Therefore, during this first period, red light is irradiated as artificial light in order to efficiently perform photosynthesis and morphogenesis and promote growth.
Here, the wavelength range of the red light is, for example, 600 nm to 700 nm. The light emitted from the red light irradiator for irradiating the plant with red light preferably has a peak wavelength range of, for example, 635 nm to 660 nm. In this case, since the peak wavelength of the emitted light from the light irradiator for red light is substantially the same as the absorption peak wavelength of chlorophyll (about 660 nm), the growth of plants can be promoted efficiently.

The artificial light emitted during the first period may be dominated by red light, and may be, for example, white light or mixed light of red light and white light. Here, the wavelength range of the white light is 300 nm to 800 nm.
An LED is an example of a light irradiator that irradiates a plant with artificial light. Here, the white LED is cheaper than the red LED. Therefore, by irradiating the white light with the white LED, the plant can be grown at a lower cost as compared with the case of irradiating the red light with the red LED. Further, when the white light is irradiated, the visibility of the plant can be ensured and the workability of the operator can be improved. However, when only the promotion of plant growth is considered, it is preferable to irradiate only red light.

[Second period]
The second period is the period until the third period of the final stage of the color development stage following the growth stage is entered, and is the period of irradiating artificial light to control the color of the plant in addition to the growth (elongation) of the plant. Is.
In this second period, red light and blue light are irradiated as artificial light.
Here, the wavelength range of the red light is the same as that of the first period described above. The wavelength range of the blue light is, for example, 400 nm to 500 nm. The light emitted from the blue light irradiator for irradiating the plant with blue light preferably has a peak wavelength range of, for example, 400 nm to 460 nm.

Irradiating plants, especially leafy vegetables, with blue light has the effect of increasing, for example, anthocyanins in plants. For example, when the plant is red leaf lettuce, the color of the leaves changes to red by irradiating with blue light, and the color becomes better.

The artificial light to be irradiated during the second period may be any light that is dominated by red light and contains blue light, for example, white light, or red light, white light, and blue light. It may be mixed light.
Further, this second period may be a period for growing (elongating) the plant as in the first period. In this case, in the second period, the same artificial light as in the first period, that is, red light, white light, or mixed light of red light and white light is irradiated.

[Third period]
The third period is a period in which artificial light is irradiated to control the color of the plant.
This third period is a period at the end of the color development stage, and can be, for example, a period from 3 days before harvest to harvest.
In this third period, blue light is irradiated as artificial light. The wavelength range of the blue light is the same as that of the second period described above.

Here, as shown in FIG. 2, when the blue light is irradiated in the second period, the ratio of the blue light is increased in the third period as compared with the second period. That is, as shown in FIG. 2, when the amount of red light is constant between the second period and the third period, the amount of blue light is increased in the third period as compared with the second period.
The intensity of the blue light irradiated in the third period may be a predetermined intensity set in advance, or may be, for example, an intensity corresponding to the color of the leaves at the end of the second period.

As described above, in the present embodiment, the entire growing period of the plant is divided into three periods, and the wavelength of the artificial light irradiating the plant in each period is switched as described above. This makes it possible to control not only the growth of the plant but also the color of the plant.

As a comparative example, FIG. 3 shows an irradiation example in which the intensity of blue light to be irradiated in the color development stage (second period and third period) is constant.
Further, FIG. 4 shows that the intensity of the blue light is increased in the case where the intensity of the blue light irradiated in the color development stage is constant as shown in FIG. 3 and in the third period which is the final stage of the color development stage as shown in FIG. This is the result of comparing the degree of color development of the plant with that of the case where the plant was allowed to develop. Here, the plant to be irradiated is red leaf lettuce.
In FIG. 4, “x” indicates insufficient color development, “Δ” indicates insufficient color development, but color development is improved, and “◯” indicates that there is no problem in shipping.

As shown in FIG. 4A, when the red leaf lettuce was irradiated with artificial light in the irradiation pattern shown in FIG. 3, the red leaf lettuce was colored, but the color was insufficient.
On the other hand, when the red leaf lettuce was irradiated with artificial light using the irradiation pattern shown in FIG. 2, the color of the red leaf lettuce was improved as compared with the case where the artificial light was irradiated with the irradiation pattern shown in FIG. Specifically, as shown in FIG. 4B, although the color was insufficient for shipment one day before shipment, the improvement in color was remarkable, and there was a problem with shipment on the shipment date. There was no color.
In this way, it was confirmed that the color of the plant was improved by actively irradiating the blue light in the third period, which is the final stage of the color development stage.

In the irradiation pattern shown in FIG. 2, the blue light intensity is increased at the transition from the second period to the third period, but as shown in FIG. 5, the blue light intensity is gradually increased in the second period. , The blue light intensity may be constant at a desired intensity in the third period.
In this case, since it is possible to suppress the excessive irradiation of blue light in the early stage of the second period, it is possible to appropriately develop the color of the plant while suppressing the suppression of the growth of the plant in the early stage of the second period.

Further, in the irradiation pattern shown in FIG. 2, the red light intensity is constant during the entire growing period, but as shown in FIG. 6, the red light intensity may be reduced during the third period.
Further, as shown in FIG. 7, in the third period, only blue light may be irradiated. That is, in the third period, light that does not contain red light may be irradiated. Further, when only blue light is irradiated in the third period, the blue light intensity may be constant in the second period and the third period as shown in FIG.
Further, in the irradiation pattern shown in FIG. 2, the blue light intensity is constant in the third period, but in this third period, the blue light intensity may be changed according to the degree of color development of the plant.

FIG. 9 is a diagram showing a schematic configuration example of a plant growing device 10 for realizing the above plant growing method.
The plant growing device 10 includes a first light source 11 and a second light source 12.
The first light source 11 is an irradiator that emits artificial light L1 that irradiates the plant 20 at least in the first period and the second period of the above-mentioned total growing period. The artificial light L1 is red light, white light, or mixed light of red light and white light.
The first light source 11 can be, for example, an SMD line light source in which SMDs (2 Chips Surface Mount Devices) mounted by combining one red LED and one white LED are linearly arranged. When irradiating light of either one color, a monochromatic line light source or a monochromatic panel light source in which only red LEDs or white LEDs are arranged in a plane can be used.

The second light source 12 is an irradiator that emits artificial light L2 that irradiates the plant 20 at least in the third period of the above-mentioned second period and third period. The artificial light L2 is blue light.
The second light source 12 can be, for example, a monochromatic line light source or a monochromatic panel light source in which only blue LEDs are arranged in a plane.

The first light source 11 and the second light source 12 are fed by the power feeding device 13. The power supply device 13 is controlled by the control unit 14 to control on / off of power supply to each LED of each light source, the magnitude of power to be supplied, and the like.
For example, when irradiating artificial light with the irradiation pattern shown in FIG. 2, the control unit 14 controls the power feeding device 13 so as to irradiate red light from the first light source 11 during the entire growth period. Further, the control unit 14 controls the power feeding device 13 so as not to irradiate the blue light from the second light source 12 in the first period but to irradiate the blue light from the second light source 12 in the second period and the third period. do. At this time, the control unit 14 controls the power feeding device 13 so that the blue light intensity from the second light source 12 is higher than that in the second period in the third period.

As shown in FIG. 9, a plurality of the first light source 11 and the second light source 12 can be arranged alternately in the left-right direction of the paper surface. Further, a plurality of the first light source 11 and the second light source 12 can be alternately arranged in the direction perpendicular to the paper surface in FIG.
The distance between the first light source 11 and the second light source 12 and the growing plant 20 can be, for example, 250 to 400 mm. Further, the photosynthetic photon bundle density (PPFD) on the plant surface can be, for example, 200 to 300 μmol / m ² s.

In the present embodiment, the case where the first light source 11 and the second light source 12 are LEDs has been described, but the present invention is not limited to this, and for example, a laser diode (LD) or electroluminescence (EL) may be used.

Optical semiconductor devices such as LEDs and LDs are small and have a long life, and they are energy efficient because they emit light at a specific wavelength depending on the material and do not emit unnecessary heat. It doesn't happen.
Therefore, by using the optical semiconductor element as the light source, it is possible to cultivate the light source at a lower power cost and in a smaller space than other light sources.

As described above, in the plant growing method in the present embodiment, the entire growing period of the plant from planting to harvesting is divided into three periods of the first period, the second period, and the third period in chronological order, and each period. Controls the wavelength of the light that irradiates the plant. Specifically, during the first period, the plant is irradiated with red light as the main irradiation light, and during the third period, the plant is irradiated with blue light as the main irradiation light.
In this way, after planting, the plant is first irradiated with red light that promotes the growth of the plant, and then the plant is irradiated with blue light at the end of the growing period to stimulate the plant. Therefore, it is possible to control not only the growth of the plant but also the color of the plant, and it is possible to grow a large-grown plant having a good color.

Here, the first period can be a period from planting to at least 1/3 of the total growing period in the total growing period. When about 1/3 of the total growing period has passed since planting, as shown in FIG. 1, it is a change point at which the plant starts to grow smoothly. By irradiating the plant with red light as the main irradiation light during the period from the planting to the change point, the growth of the plant can be effectively promoted.

In addition, the third period may be at least three days before harvesting out of the total growing period. In this way, by irradiating the plant with blue light for at least the last three days of the entire growing period, the color of the plant can be appropriately improved.
Further, in this third period, the intensity (or ratio) of blue light is made larger than the intensity (or ratio) of blue light contained in the irradiation light irradiated to the plants in the first period and the second period. , It is possible to appropriately improve the color of the plant while suppressing the suppression of the growth of the plant.

In addition, during the second period, the plant can be irradiated with red light as the main irradiation light. In this way, the plant can be further grown by irradiating the red light in the second period following the first period.
Further, during this second period, irradiation light mainly including red light and including blue light can be irradiated. In this case, in the second period, in addition to the growth (elongation) of the plant, the color of the plant can also be controlled.

As described above, in the present embodiment, the growth and color of the plant can be appropriately controlled by controlling the artificial light irradiating the plant according to the growth of the plant.

The plants to be cultivated are leafy plants (leaf vegetables), for example, cruciferous Mizuna, Komatsuna, Karashimizuna, Karashina, Wasabina, Cresson, Chinese cabbage, Tsukena, Bok choy, cabbage, cabbage, broccoli, mechabetsu, arugula, etc. Pino green, etc .; Chinese cabbage lettuce, salad na, shungiku, fuki, lororossa, red romaine, chicoly, etc .; lily family onion, garlic, arugula, nira, asparagus, etc. , Seri, etc .; Chinese cabbage, Basil, etc .; Cruciferous, Negi, etc .; Arugula, Udo, etc., Ginger family: Myoga, etc.

The lettuce includes head lettuce, non-head lettuce, semi-head lettuce and the like, for example, leaf lettuce, frill lettuce, romaine, green wave, green leaf, red leaf, frill ice (registered trademark), river green (registered trademark). Registered trademarks), frill leaf, fringe green, no chip, mocollettuce, sanchu, chima sanchu.

10 ... plant growing device, 11 ... first light source, 12 ... second light source, 13 ... power feeding device, 14 ... control unit, 20 ... plant

Claims (10)

Of the entire growing period of the plant from planting to harvesting, the first step of irradiating the plant with red light as the main irradiation light during the period from the planting to the first period,
Of the total growing period, the second step of irradiating the plant with blue light as the main irradiation light during the third period from the end of the second period following the first period to the harvesting is included. A plant growing method characterized by this. The plant growing method according to claim 1, wherein the first period is a period from the planting to at least 1/3 of the total growing period in the total growing period. The plant growing method according to claim 1 or 2, wherein the third period is a period of at least 3 days before the harvesting among the total growing periods. The plant growing method according to any one of claims 1 to 3, further comprising a third step of irradiating the plant with red light as the main irradiation light during the second period. The third step is a step of irradiating the plant with the irradiation light including blue light during the second period.
The plant growing method according to claim 4, wherein in the third step, the intensity of the blue light is gradually increased during the second period. In the second step,
The intensity of the blue light contained in the irradiation light irradiating the plant in the third period is made larger than the intensity of the blue light contained in the irradiation light irradiating the plant in the first period and the second period. The plant growing method according to any one of claims 1 to 5, wherein the plant growing method is characterized by the above. In the second step,
The ratio of the intensity of blue light contained in the irradiation light irradiating the plant in the third period is the ratio of the intensity of blue light contained in the irradiation light irradiating the plant in the first period and the second period. The plant growing method according to any one of claims 1 to 6, wherein the plant is made larger than the above. In the second step,
The plant growing method according to any one of claims 1 to 7, wherein the plant is irradiated with the irradiation light containing no red light during the third period. The plant growing method according to any one of claims 1 to 8, wherein the plant is a leafy plant. A first light source that emits red light as the main emitted light,
A second light source that emits blue light as the main emitted light,
A control unit that controls the first light source and the second light source to irradiate plants with light is provided.
The control unit
Of the entire growing period of the plant from planting to harvesting, during the first period from the planting, the light emitted from the first light source is irradiated to the plant as irradiation light.
During the third period from the end of the second period following the first period to the harvesting of the entire growing period, the plant is irradiated with the light emitted from the second light source as irradiation light. A plant growing device characterized by.

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