JP6886656B2 - Program for plant growing system, plant growing method and plant growing system - Google Patents

Description

The present invention relates to a plant growing system for growing a plant by controlling the leaf temperature with a radiation thermometer, a plant growing method, and a program for the plant growing system.

Conventionally, a method of growing edible plants by a plant factory has become widespread. A plant factory is a system that can produce plants regardless of the season by artificially controlling the environment required for plant growth in the facility by lighting, air conditioning, nutrient solution supply, etc. ..

As a method of growing a plant by a plant factory, a technique of measuring the leaf temperature, which is the temperature of the leaf surface of the plant, and managing the growing state of the plant based on the measured temperature has been conventionally known. For example, in Patent Document 1, the leaf temperature of a growing plant is measured with a radiation thermometer, and when the measured leaf temperature value starts to vibrate, the temperature in the growing room and the amount of water injected into the plant are controlled. , A technique for managing the plants to be grown so as not to die is disclosed.

However, in the conventional plant growing method disclosed in Patent Document 1, although it is possible to control the leaf temperature with a radiation thermometer to prevent the grown plant from dying, the degree of growth of the plant is increased to increase the yield. Leaf temperature was not controlled to increase.

Japanese Unexamined Patent Publication No. 63-39212

Therefore, an object of the present invention is to provide a plant growing system, a plant growing method, and a program for a plant growing system capable of increasing the degree of plant growth and increasing the yield.

The present inventors have conducted studies from various angles in order to achieve the above object. As a result of diligent studies, it is possible to promote the growth of plants by controlling the plant growth environment so that the leaf temperature in the dark period is higher than the leaf temperature in the light period, and the plants per unit period. For the first time, we found that we could increase the yield of.

That is, the plant growing system according to the present invention grows a plant in a growing environment in which a light period and a dark period are alternately repeated, and a radiation thermometer for measuring the leaf temperature of the plant and the measurement. The control unit is provided with a control unit that controls the growing environment of the plant based on the leaf temperature, and the control unit has a part of the light period in which the average temperature of the leaf temperature during a part or the whole period of the dark period is It is characterized in that the growing environment of the plant is controlled so as to be equal to or higher than the average temperature of the leaf temperature during the period or the whole period.

In such a case, by making the leaf temperature of the plant in the dark period higher than the leaf temperature of the plant in the light period, the degree of growth of the plant in the growing period can be increased, and the degree of growth of the plant per unit period can be increased. The yield can be increased.

Since the leaf temperature of the grown plant is measured in the plant growing system according to the present invention, the transpiration action on the leaf surface of the plant can be accurately grasped. Furthermore, since the leaf temperature is measured using a radiation thermometer that does not physically contact the leaf surface, instead of a contact-type thermometer such as thermoelectric pair, the leaves are not damaged. , The transpiration action can be grasped more accurately.
As described above, since the plant growing system according to the present invention measures the temperature of the leaf surface using a radiation thermometer, the transpiration action on the leaf surface can be grasped with extremely high accuracy. Transpiration on the leaf surface is closely related to the opening and closing of stomata on the leaf surface, and the opening and closing of the stomata is closely related to the photosynthetic reaction of plants. In other words, it can be said that the photosynthetic reaction (whether or not photosynthesis is performed) of a plant can be accurately grasped by accurately grasping the transpiration action on the leaf surface.
That is, the leaf temperature measured in the plant growing system according to the present invention reflects the transpiration action, which is a action closely related to the photosynthetic reaction, with high accuracy. Therefore, by controlling the growing environment of the plant and controlling such leaf temperature, it is possible to substantially control the photosynthetic reaction of the growing plant with high accuracy.

In the present specification, the "light period" means a period in which the amount of light applied to the growing plant is equal to or more than a predetermined value, and the "dark period" means a period in which the amount of light emitted is less than a predetermined value. It means a certain period. The "light period" and "dark period" can be appropriately set depending on the type of plant to be cultivated and the method of irradiating light in the growing environment.

For example, the "light period" is the period during which the growing plant is irradiated with light in an amount sufficient to photosynthesize, and the "dark period" is the period in which the growing plant performs photosynthesis. It may be a period during which a possible amount of light is not irradiated, that is, a period other than the "light period" in the growing period.

In another example, the "light period" is the period during which the plant to be cultivated is irradiated with light stronger than the light compensation point, and the "dark period" is the same intensity as the light compensation point, or it. It may be a period during which the growing plant is irradiated with light of weaker intensity. The light compensation point is the intensity of light at which the photosynthetic rate and the respiration rate of the growing plant become equal and the carbon dioxide balance apparently becomes zero.

In the plant growing system according to the present invention, specific aspects of the growing environment to be controlled include the temperature or humidity of the atmosphere for growing the plant, the component, concentration, pH or liquid temperature of the nutrient solution supplied to the plant, and the plant. The illuminance or wavelength of the light to be irradiated, the concentration or supply amount of carbon dioxide supplied to the plant, or the air volume supplied to the plant can be mentioned.
By appropriately selecting and controlling these various growing environments as parameters for controlling the photosynthetic rate of the plant to be grown (also referred to as photosynthetic rate control parameter), the photosynthetic rate of the plant to be grown can be controlled more strictly. , The leaf temperature of plants in the light and dark periods can be controlled more accurately. As a result, the growth rate of the plant can be further increased.

Plants plant growing system according to the present invention targets, C ₃ plants are preferred, especially, is preferably a leafy vegetable.
In such a plant, the plant growing system according to the present invention raises the leaf temperature of the plant in the dark period to be higher than the leaf temperature of the plant in the light period, thereby further increasing the degree of growth of the plant in the growing period. It is possible to increase the yield of plants per unit period.

In the plant growing system according to the present invention, when the growing target is leaf lettuce, it is preferable to control the average temperature of the atmosphere in which the leaf lettuce is grown to 19 ° C. or higher and 25 ° C. or lower.

If it is such a thing, the growth degree of leaf lettuce in the growing period can be further increased, and the yield can be increased.

Further, the plant growing method according to the present invention grows a plant in a growing environment in which light and dark periods are alternately repeated, and measures the leaf temperature of the plant using a radiation thermometer. The growing environment of the plant is controlled so that the average temperature of the leaf temperature during a part or all of the dark period is equal to or higher than the average temperature of the leaf temperature during a part or all of the light period. It is characterized by that.

With such a plant growing method, the same action and effect as the above-mentioned plant growing system of the present invention can be obtained.

Further, the program for a plant growing system according to the present invention is provided with a radiation thermometer for measuring the leaf temperature of a plant, and is a plant growing system for growing the plant in a growing environment in which a light period and a dark period are alternately repeated. It is used, and based on the measured leaf temperature, the average temperature of the leaf temperature in a part or all of the dark period is the average of the leaf temperature in a part or all of the light period. It is characterized in that the computer exerts a function as a control unit that controls the growing environment of the plant so that the temperature becomes higher than the temperature.

By installing such a program for a plant growing system on a plant growing system that measures leaf temperature using a radiation thermometer, the same action and effect as the above-mentioned plant growing system of the present invention can be obtained. .. Such a program for a plant growing system may be electrically distributed, or may be installed in an existing device using a program stored in a program storage medium such as a CD, DVD or flash memory. You may.

According to the present invention configured in this way, the leaf temperature is measured using a radiation thermometer, and the growth environment of the plant is controlled based on the measured leaf temperature to increase the growth rate of the plant and increase the yield. It is possible to provide a plant growing system, a plant growing method and a program for a plant growing system that can be increased.

It is a figure which shows typically the whole structure of the plant growing system 100 of this embodiment. It is a flowchart which shows the operation of the control device 20 in the dark period of the same embodiment. It is a flowchart which shows the operation of the control device 20 in the light period of the same embodiment. It is a graph which shows an example of the temperature change of a leaf temperature in the cultivation of leaf lettuce of an Example. It is a graph which shows the relationship between the difference between the average temperature of the leaf temperature in the light period and the average temperature of the leaf temperature in the dark period, and the body weight of the above-ground part in the cultivation of leaf lettuce of the example.

Hereinafter, an embodiment of the plant growing system according to the present invention will be described with reference to the drawings.

The plant growing system 100 according to the present embodiment is for hydroponically cultivating plant X in a completely artificial environment using artificial light. Specifically, as shown in FIG. 1, the plant growing system 100 radiates leaf temperature information, which is information on the leaf temperature of plant X, and a growing room 10 having a radiation thermometer 12 for measuring the leaf temperature of plant X. It is provided with a control device 20 that obtains from the thermometer 12 and controls the growing environment in the growing room 10.
The plant X of the present embodiment is an edible plant, specifically leaf lettuce.
Hereinafter, each configuration will be described.

The growing room 10 accommodates the plant X and provides various growing environments necessary for growing the plant X, and is a radiation thermometer 12, a light irradiation device 14, a nutrient solution tank 16, and an air conditioner. It has 18 and.

The radiation thermometer 12 is provided above the plant X, measures the leaf temperature of the plant X, and acquires it as leaf temperature information. The radiation thermometer 12 has a signal transmission unit (not shown) for transmitting a signal including the acquired leaf temperature information, and the leaf temperature information acquired by the signal transmission unit is transmitted by wire or wirelessly. It is configured so that it can be transmitted to the control device 20. In the present embodiment, the leaf temperature of plant X is continuously measured during the period from germination to harvest in the growing period of plant X.

The light irradiation device 14 irradiates the plant X with light using an LED light source. Specifically, it has a signal receiving unit (not shown) for receiving a control signal including an irradiation pattern from the control device 20 via wire or wirelessly, and is based on the signal received by the signal receiving unit. Therefore, the plant X can be irradiated with light of any light quality (wavelength, amount of light, etc.) at any time zone and interval.

In the present embodiment, the light irradiation device 14 irradiates the plant X with light during the time zone (light period) from 6:00 am to 10:00 pm of the day, and from 10:00 pm to 6:00 am the next day. It is configured not to irradiate light during the time zone (dark period). The light irradiation device 14 may have a fluorescent lamp or a sodium lamp.

The nutrient solution tank 16 is configured to accommodate the plant X and to allow the nutrient solution containing the fertilizer component necessary for growing the plant X to flow. In the nutrient solution tank 16, the nutrient solution taken in from one end opening (not shown) is discharged from the other end opening (not shown), and the discharged nutrient solution is taken into the nutrient solution tank 16 again from the one end opening ( That is, it is configured to circulate).

The air conditioner 18 supplies air whose temperature and humidity are adjusted to desired values into the growing chamber 10 at a desired air volume. Specifically, it has a signal receiving unit (not shown) for receiving a control signal including target values of temperature, humidity, and air volume from the control device 20 via wire or wireless, and the signal receiving unit. It is configured to be able to supply the air whose temperature and humidity are adjusted to desired values in the growing chamber 10 based on the signal received by.

Specifically, the air conditioner 18 includes an air conditioner (not shown) to which the air in the growing chamber 10 is sent, and an air blower that sends air whose temperature and humidity are adjusted by the air conditioner into the growing chamber 10 from a plurality of air outlets. It is equipped with a duct (not shown).

The control device 20 transmits a control signal to the light irradiation device 14 and the air conditioner 18 to control the temperature and humidity in the growing room 10 and the time zone for irradiating the plant X with light. The control device 20 has a signal transmitting unit and a signal receiving unit (not shown), and is configured to be capable of transmitting and receiving signals between the radiation thermometer 12, the light irradiation device 14, and the air conditioner 18.
Specifically, the control device 20 is a computer provided with a CPU, a memory, an A / D converter, and the like, and the CPU and peripheral devices cooperate with each other according to a program stored in a predetermined area of the memory, and FIG. As shown in the above, the storage unit 21, the lighting control unit 22, the detection unit 23, the leaf temperature acquisition unit 24, the calculation unit 25, and the control unit 26 are configured to exert their functions.

The storage unit 21 is formed in a predetermined area of the memory, and stores the leaf temperature indicated by the leaf temperature information acquired by the leaf temperature acquisition unit 24 in association with time. The storage unit 21 is also supplied to the temperature or humidity in the growing chamber 10, the component, concentration, pH or liquid temperature of the nutrient solution supplied to the plant X, the illuminance or wavelength of the light irradiating the plant X, and the plant X. The fluctuation value (or increase / decrease value) of the photosynthetic rate control parameter of plant X such as the concentration or supply amount of carbon dioxide or the air volume supplied to plant X, and the fluctuation value (or increase / decrease value) of the leaf temperature of plant X. , Light and dark periods are associated and memorized.
More specifically, for example, a mode in which the fluctuation value of the photosynthesis rate control parameter and the fluctuation value of the leaf temperature of the plant X are stored in the look-up table can be mentioned. In addition, an embodiment in which a calculation formula for calculating the fluctuation value of the plant X is stored with the fluctuation value of each photosynthesis rate control parameter as a variable can be mentioned.

The lighting control unit 22 transmits a control signal including an irradiation pattern to the light irradiation device 14 via a wire or wirelessly.
The lighting control unit 22 of the present embodiment is configured to transmit a control signal for turning on the lighting to the light irradiation device 14 only during the time zone from 6:00 am to 10:00 pm of the day. ing.

The detection unit 23 detects the light period and the dark period in the growing environment in the growing room 10. The detection unit 23 of the present embodiment detects the light period and the dark period according to the time, and detects the time zone from 6:00 am to 10:00 pm as the light period in the day, and 10:00 pm It is configured to detect as a dark period until 6:00 am the next day.

The leaf temperature acquisition unit 24 acquires leaf temperature information from the radiation thermometer 12 via a wired or wireless device.

The calculation unit 25 receives leaf temperature information from the leaf temperature acquisition unit 24, and from the detection unit 23, information indicating whether the growing environment in the growing room 10 is in the light period or the dark period (hereinafter, both light and dark information). In addition to receiving (referred to as), the storage unit 21 is referred to to determine the increase / decrease value of various photosynthesis rate control parameters.

Specifically, when the light / dark information detected by the detection unit 23 indicates a dark period (or light period), the calculation unit 25 determines the average temperature of the leaf temperature of the plant X in the immediately preceding light period (or dark period). The average leaf temperature value in the immediately preceding light period (or the average leaf temperature value in the immediately preceding dark period) is calculated, and the calculated average leaf temperature value in the immediately preceding light period (or the average leaf temperature value in the immediately preceding dark period) and the current leaf temperature value are used. To compare. Then, when the value of the difference obtained by subtracting the average leaf temperature value in the immediately preceding light period from the current leaf temperature value (or the value obtained by subtracting the current leaf temperature value from the average leaf temperature value in the immediately preceding dark period) is less than 0. , The fluctuation value (increase / decrease value) of various photosynthesis rate control parameters is determined so that the value of the difference becomes 0 or more.
When the value of the difference is 0 or more, the fluctuation value (increase / decrease) of various photosynthesis rate control parameters is further increased so that the value of the difference becomes a predetermined value (also referred to as a threshold value) larger than a preset value of 0. Value) is determined. When the value of the difference is equal to or more than a predetermined value set in advance, the fluctuation value (increase / decrease value) of various photosynthesis rate control parameters is determined to be 0.

The control unit 26 acquires the fluctuation value of the photosynthesis rate control parameter determined by the calculation unit 25, and transmits a control signal to various devices and the like based on the fluctuation value.
In the present embodiment, a control signal including fluctuation values (increase / decrease values) such as temperature, humidity, and air volume of the air supplied into the growth chamber 10 is transmitted to the air conditioner 18.

<Operation of control device 20>
Next, the operation of the control device 20 in the plant growing system 100 according to the present embodiment will be described with reference to the flowcharts of FIGS. 2 and 3.

(Operation in the dark period)
When the light / dark information detected by the detection unit 23 indicates a dark period, the leaf temperature acquisition unit 24 first acquires the leaf temperature information from the radiation thermometer 12 as shown in FIG. 2 (step S _d 1). The leaf temperature acquisition unit 24 transmits the acquired leaf temperature information to the storage unit 21 and the calculation unit 25.

Next, the calculation unit 25 calculates the average leaf temperature value in the immediately preceding light period with reference to the storage unit 21 (step S _d 2).

Next, the calculation unit 25 compares the calculated average leaf temperature value in the immediately preceding light period with the current leaf temperature value indicated by the leaf temperature information received from the leaf temperature acquisition unit 24 (step S _d 3). Then, the calculation unit 25 determines whether or not the value obtained by subtracting the average leaf temperature value in the immediately preceding light period from the current leaf temperature value is 0 or more (step S _d 4).

When the calculation unit 25 determines in step _Sd 4 that the value obtained by subtracting the average leaf temperature value in the immediately preceding light period from the current leaf temperature value is less than 0, the calculation unit 25 refers to the storage unit 21 and determines that the difference is The fluctuation value of the photosynthesis rate control parameter for setting the value to 0 or more is determined (step S _d 5).

The control unit 26 acquires the fluctuation value determined by the calculation unit 25, and transmits a control signal including the fluctuation value to the air conditioner 18 (step S _d 6). As a result, the values of the temperature, humidity, air volume, etc. of the air supplied from the air conditioner 18 into the growing chamber 10 fluctuate, and the value obtained by subtracting the average leaf temperature value in the immediately preceding light period from the current leaf temperature value becomes 0 or more. In addition, the leaf temperature of plant X fluctuates. After that, _{the operations of steps S d} 3 and S _d 4 are performed again.

When the calculation unit 25 determines in step S _d 4 that the value obtained by subtracting the average leaf temperature value in the immediately preceding light period from the current leaf temperature value is 0 or more, the value of the difference is further determined to be greater than 0. It is determined whether or not the value (threshold value) is equal to or higher than the value (threshold value) (step S _d 5).

When the value of the difference is less than the predetermined value, the storage unit 21 is referred to to determine the fluctuation value of the photosynthesis rate control parameter for making the difference value equal to or more than the predetermined value (. Step S _d 5). The control unit 26 acquires the fluctuation value determined by the calculation unit 25, and transmits a control signal including the fluctuation value to the air conditioner 18 (step S _d 6). As a result, the values of the temperature, humidity, air volume, etc. of the air supplied from the air conditioner 18 into the growing chamber 10 fluctuate, and the value obtained by subtracting the average leaf temperature value in the immediately preceding light period from the current leaf temperature value is equal to or higher than the predetermined value. The leaf temperature of plant X fluctuates so as to become. After that, the operations of steps S _d 3, S _d 4 and S _d 7 are performed again.

When the calculation unit 25 determines in step _Sd 7 that the value obtained by subtracting the average leaf temperature value in the immediately preceding light period from the current leaf temperature value is equal to or greater than the predetermined value, the calculation unit 25 determines the fluctuation value of the photosynthesis rate control parameter. Determine to 0. In this case, the control unit 26 does not transmit the control signal including the fluctuation value to the air conditioner 18. That is, the values of the temperature, humidity, air volume, etc. of the air supplied from the air conditioner 18 into the growing chamber 10 are maintained without fluctuating.

(Operation in the light period)
When the light / dark information detected by the detection unit 23 indicates the light period, the leaf temperature acquisition unit 24 first acquires the leaf temperature information from the radiation thermometer 12 as shown in FIG. 3 (step S _l 1). The leaf temperature acquisition unit 24 transmits the acquired leaf temperature information to the storage unit 21 and the calculation unit 25.

Next, the calculation unit 25 calculates the average leaf temperature value in the immediately preceding dark period with reference to the storage unit 21 (step S _l 2).

Next, the calculation unit 25 compares the calculated average leaf temperature value in the immediately preceding dark period with the current leaf temperature value indicated by the leaf temperature information received from the leaf temperature acquisition unit 24 (step S _l 3). Then, the calculation unit 25 determines whether or not the value obtained by subtracting the current leaf temperature value from the average leaf temperature value in the immediately preceding dark period is 0 or more (step S _l 4).

When the calculation unit 25 determines in step S _l4 that the value obtained by subtracting the current leaf temperature value from the average leaf temperature value in the immediately preceding dark period is less than 0, the calculation unit 25 refers to the storage unit 21 and determines that the difference is The fluctuation value of the photosynthesis rate control parameter for setting the value to 0 or more is determined (step S _l 5).

The control unit 26 acquires the fluctuation value determined by the calculation unit 25, and transmits a control signal including the fluctuation value to the air conditioner 18 (step S _l 6). As a result, the values of the temperature, humidity, air volume, etc. of the air supplied from the air conditioner 18 into the growing chamber 10 fluctuate, and the value obtained by subtracting the current leaf temperature value from the immediately preceding dark period average leaf temperature value becomes 0 or more. In addition, the leaf temperature of plant X fluctuates. After that, _{the operations of steps S l} 3 and S _l 4 are performed again.

When the calculation unit 25 determines in step S _l4 that the value obtained by subtracting the current leaf temperature value from the immediately preceding dark period average leaf temperature value is 0 or more, the value of the difference is further determined to be greater than 0. It is determined whether or not the value (threshold value) is equal to or higher than the value (threshold value) (step S _l 5).

When the value of the difference is less than the predetermined value, the storage unit 21 is referred to to determine the fluctuation value of the photosynthesis rate control parameter for making the difference value equal to or more than the predetermined value (. Step S _l 5). The control unit 26 acquires the fluctuation value determined by the calculation unit 25, and transmits a control signal including the fluctuation value to the air conditioner 18 (step S _l 6). As a result, the values of the temperature, humidity, air volume, etc. of the air supplied from the air conditioner 18 into the growing chamber 10 fluctuate, and the value obtained by subtracting the current leaf temperature value from the immediately preceding dark period average leaf temperature value is equal to or higher than the predetermined value. The leaf temperature of plant X fluctuates so as to become. After that, the operations of steps S _l 3, S _l 4, and S _l 7 are performed again.

When the calculation unit 25 determines in step S _l 7 that the value obtained by subtracting the current leaf temperature value from the immediately preceding dark period average leaf temperature value is equal to or greater than the predetermined value, the calculation unit 25 determines the fluctuation value of the photosynthesis rate control parameter. Determine to 0. In this case, the control unit 26 does not transmit the control signal including the fluctuation value to the air conditioner 18. That is, the values of the temperature, humidity, air volume, etc. of the air supplied from the air conditioner 18 into the growing chamber 10 are maintained without fluctuating.

<Effect of this embodiment>
According to the plant growing system 100 of the present embodiment configured in this way, the leaf temperature of the plant X is measured using a radiation thermometer, and the air conditioner 18 is controlled based on the measured leaf temperature to control the plant. The average temperature of the leaf temperature in the dark period during the growing period of X can be made equal to or higher than the average temperature of the leaf temperature in the light period during the same period.
As a result, the degree of growth of the plant X during the growing period can be increased and the yield can be increased.

<Other Embodiments>
The present invention is not limited to the above-described embodiment.

The plant X of the above-described embodiment was leaf lettuce, but in other embodiments, the plant X may be another plant of the Asteraceae family. For example, lettuce such as head lettuce, saladana, stem lettuce, santu, cos lettuce, baby leaf and the like can be mentioned. Plant X also includes herbs such as arugula and basil, headed vegetables such as cabbage, trevis and Chinese cabbage, fruit vegetables such as eggplant, cucumber and tomato, root vegetables such as carrots and radishes, as well as komatsuna, spinach, spring chrysanthemum and stevia. It may be any one selected from leafy vegetables such as cauliflower, broccoli, rape blossoms, Chinese cabbage such as artichoke, and other flowers.

The plant growing system 100 of the above-described embodiment grows the plant X in a completely artificial environment using the light irradiation device 14, whereas the plant growing device 100 of the other embodiment is a half using sunlight. It may grow plants in an artificial environment. In such an embodiment, the detection unit 23 detects the time zone from sunrise to the next sunset (that is, noon) as the "light period", and the time zone from sunset to the next sunrise is the "dark period". It may be configured to detect as.

In the above-described embodiment, the time zone in which the light of the light irradiation device 14 is turned on is defined as the "light period", and the time zone in which the light of the light irradiation device 14 is turned off is defined as the "dark period". Not limited. For example, the amount of light emitted from the light irradiation device 14 is adjusted, and the time zone for irradiating light equal to or more than a predetermined amount and the time zone for irradiating light less than a predetermined amount are repeated to grow plant X. In this case, the detection unit 23 detects a time zone in which light equal to or greater than a predetermined amount is irradiated as a "light period", and a time zone in which light less than a predetermined amount of light is irradiated is a "dark period". It may be urged to detect as.

The detection unit 23 described above detects the light period and the dark period according to the time zone or time, but is not limited to this.
For example, the light period and the dark period may be detected based on the illuminance in the growing room 10 acquired by a sensor such as an illuminance sensor provided in the growing room 10. In such a case, if the illuminance in the growing chamber 10 is equal to or more than a predetermined value, it may be detected as a light period, and if it is less than a predetermined value, it may be detected as a dark period.
Alternatively, the detection unit 23 may detect the light period and the dark period based on the leaf temperature indicated by the leaf temperature information acquired by the leaf temperature acquisition unit 24. In such a case, it may be detected that the light period and the dark period in the growing room 10 are switched due to the change of the leaf temperature by a predetermined value or more.

The radiation thermometer 10 of the above-described embodiment continuously measures the leaf temperature of the plant X during the germination-harvest period of the growing period of the plant X, but intermittently at predetermined time intervals. It may be configured to measure leaf temperature.

In the above-mentioned plant growing system 100, the growing environment in the growing room 10 is controlled by controlling the temperature, humidity, and air volume of the air supplied by the air conditioner 18, but the present invention is not limited to this. In another embodiment, _{a cylinder accommodating CO 2} may be connected to the air duct of the air conditioner 18 via a supply pipe, and a desired amount of CO ₂ may be supplied from the air duct into the growing chamber 10. Good. In this case, a solenoid valve whose opening degree can be adjusted by a signal is provided in the supply pipe, the opening degree of the solenoid valve is adjusted by a control signal transmitted from the control unit 26, and the amount of _{CO 2 supplied into the growing chamber 10 is adjusted.} It may be controlled.

The plant growing system 100 of another embodiment may further include a nutrient solution supply device that supplies and circulates the nutrient solution to the nutrient solution tank 16. In this case, even if the nutrient solution supply device is configured to supply the nutrient solution adjusted to a predetermined component, component concentration, dissolved oxygen concentration, pH and liquid temperature to the nutrient solution tank 16 at a desired flow rate. Good. The nutrient solution tank 16 is provided with a pH meter for measuring the pH of the circulating nutrient solution and an electric conductivity meter for measuring the electrical conductivity, and either the measured pH or the electrical conductivity is within a predetermined range. If it comes off, it is preferable that the pH and electrical conductivity are returned to the predetermined ranges by the automatic topdressing device.
Specifically, when the pH in the nutrient solution tank 16 deviates from the set range, it is preferable to add a pH adjuster (up agent or down agent) so as to return to the set range.
When the EC in the nutrient solution tank 16 is lower than the set value, it is preferable to add a concentrated nutrient solution having a concentration of about 100 times the set concentration so as to return to the set range.

As a specific configuration of the nutrient solution supply device, a nutrient solution storage tank for storing nutrient solution, a nutrient solution introduction pipe connecting the nutrient solution storage tank and one end opening of the nutrient solution tank 16, the nutrient solution tank 16 and others. It is preferable to provide a nutrient solution outlet pipe that connects the end opening and the nutrient solution storage tank, and a pressure feed pump that pumps a predetermined amount of nutrient solution to the nutrient solution tank 16 via the nutrient solution introduction pipe.

In addition, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

In order to confirm the applicability of the present invention, laboratory experiments were carried out as follows.

<Materials and methods>
As a plant to be cultivated, "Green Wave", which is a variety of leaf lettuce, which is an edible plant, was used. Four breeding chambers (chambers A to D) that can be hydroponically cultivated in a completely artificial environment using artificial light are prepared, and leaf lettuce is cultivated one by one at different set temperatures in each chamber. Was carried out 9 times (that is, 36 leaf lettuce were cultivated). The set temperatures of the growing chambers A to D were [A: 15 ° C., B: 20 ° C., C: 25 ° C., D: 30 ° C.] for the 1st to 3rd times, and [A: 19 ° C., B] for the 4th to 9th times. : 22 ° C., C: 25 ° C., D: 28 ° C.].

The leaf lettuce was irradiated with artificial light by LED lighting (EM11346660 manufactured by Especmic Co., Ltd.) provided in the upper part of the chamber. During the leaf lettuce growing period, the lights were turned on (light period) from 6:00 am to 10:00 pm, and turned off (dark period) from 10:00 pm to 6:00 am the next day. ..

Of the leaf lettuce growing environment, the components, concentration, pH, concentration and flow rate of the nutrient solution supplied to the nutrient solution tank, and the CO ₂ concentration supplied to the chambers are the same conditions in all the growing chambers. I set it like this.
・ Ingredients of nutrient solution: Otsuka A prescription (OAT Agrio Co., Ltd.)
-Concentration of nutrient solution: EC 2.0 ± 0.2 dS / m
-The pH of the nutrient solution: 5.5-6.5
・ Temperature of nutrient solution: Approximately 20 ℃
・ Flow rate of nutrient solution: Pump flow rate Approximately 1000 liters / hour ・ CO ₂ concentration of supplied air: Approximately 400 ppm

A radiation thermometer (non-contact temperature sensor IT-450S manufactured by HORIBA, Ltd.) was installed at the top of the growing chamber, and the leaf temperature of leaf lettuce during the growing period was continuously measured and plotted.
FIG. 4 shows one of the measurement results of the leaf temperature when the set temperatures of the growing chambers A to D were set to [A: 15 ° C., B: 20 ° C., C: 25 ° C., D: 30 ° C.].

After placing the leaf lettuce seeds on the seedling raising tray on the nutrient solution tank of the growing chamber, the leaf lettuce was harvested 14 days later. Then, the root part was removed from the total weight of the harvested leaf lettuce, and the above-ground body weight, which is the weight of the edible part, was measured. After harvesting, the temperature difference between day and night was calculated by subtracting the average temperature of leaf temperature in all dark periods from the average temperature of leaf temperature in all light periods during the growing period for each leaf lettuce. FIG. 5 shows a plot of the day / night temperature difference and the above-ground body weight of each leaf lettuce cultivated in this manner.

<Results and discussion>
(Relationship between the set temperature in the chamber and the leaf temperature)
As shown in FIG. 4, in the measurement in which the set temperatures of the growing chambers A to D were [A: 15 ° C., B: 20 ° C., C: 25 ° C., D: 30 ° C.], the leaves in the chambers A and D were measured. The behavior of the temperature change and the behavior of the leaf temperature change in chambers B and C were different.
Specifically, in chamber A and chamber D, the leaf temperature drops immediately after switching from the light period to the dark period, and the leaf temperature decreases from the dark period, as is clearly shown in the portion surrounded by the dotted line in the square in FIG. The leaf temperature rose immediately after switching to the light period. In addition, the leaf temperature in the light period was generally higher than that in the dark period. On the other hand, in chambers B and C, the leaf temperature increased immediately after switching from the light period to the dark period, and decreased immediately after switching from the dark period to the light period. In addition, the leaf temperature in the light period was generally lower than the leaf temperature in the dark period.
The same tendency was also seen in other examples in which the set temperatures of the growing chambers A to D were set to [A: 15 ° C., B: 20 ° C., C: 25 ° C., D: 30 ° C.].

(Relationship between day and night temperature and above-ground body weight)
As shown in FIG. 5, leaf lettuce having a day / night temperature difference of 0 ° C. or less, that is, leaf lettuce in which the average temperature of leaf temperature in the dark period during the growing period is equal to or higher than the average temperature of leaf temperature in the light period, is day and night. Compared to leaf lettuce with a temperature difference of more than 0 ° C, that is, leaf lettuce in which the average temperature of leaf temperature in the dark period during the growing period is less than the average temperature of leaf temperature in the light period, the above-ground body weight is generally larger. It turns out that there is a tendency to become.

From the above, it was confirmed that the degree of growth of leaf lettuce can be increased by setting the average temperature of the leaf temperature in the dark period during the growing period to be equal to or higher than the average temperature of the leaf temperature in the light period.

100 ... Plant growing system X ... Plant 10 ... Growing room 12 ... Radiation thermometer 20 ... Control device 26 ... Control unit

Claims (7)

It is a plant growing system that grows plants in a growing environment where light and dark periods are repeated alternately.
A radiation thermometer that measures the leaf temperature of the plant,
It is provided with a control unit that controls the growing environment of the plant based on the measured leaf temperature.
The control unit controls the plant so that the average temperature of the leaf temperature during a part or all of the dark period is equal to or higher than the average temperature of the leaf temperature during a part or all of the light period. A plant growing system characterized by controlling the growing environment. The growing environment is the temperature or humidity of the atmosphere in which the plant is grown, the component, concentration, pH or liquid temperature of the nutrient solution supplied to the plant, the illuminance or wavelength of the light irradiating the plant, and the plant being supplied. The plant growing system according to claim 1, wherein the plant growing system is one or more selected from the concentration or supply amount of carbon dioxide, or the air volume supplied to the plant. It said plant plant growing system according to claim 1 or 2 wherein the C ₃ plants. The plant growing system according to any one of claims 1 to 3, wherein the plant is a leafy vegetable. The plant growing system according to claim 4, wherein the growing environment is the temperature of an atmosphere in which the plant is grown, and the average temperature of the atmosphere is controlled to 19 ° C. or higher and 25 ° C. or lower. It is a plant growing method that grows plants in a growing environment where light and dark periods are repeated alternately.
The leaf temperature of the plant was measured using a radiation thermometer.
The growing environment of the plant is controlled so that the average temperature of the leaf temperature during a part or all of the dark period is equal to or higher than the average temperature of the leaf temperature during a part or all of the light period. A plant growing method characterized by this. It is equipped with a radiation thermometer that measures the leaf temperature of a plant, and is used in a plant growing system that grows the plant in a growing environment in which light and dark periods are repeated alternately.
Based on the measured leaf temperature, the average temperature of the leaf temperature during a part or all of the dark period is equal to or higher than the average temperature of the leaf temperature during a part or all of the light period. A program for a plant growing system, characterized in that a computer exerts a function as a control unit that controls the growing environment of the plant.

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