JP2020000188A - Cultivation system and lighting control method for cultivation system - Google Patents

Abstract

To provide techniques allowing control for a more appropriate illuminance to conditions of a plant cultivated in a cultivation system used to cultivate plants.SOLUTION: The present invention comprises: a sap flow sensor 7 which measures the sap flow rate in a plant 2 cultivated within a plastic greenhouse 3; a shade curtain 5 which blocks the path of light entering the plastic greenhouse 3 from the sun 4; and a control device that controls the degree of opening of the shade curtain 5 on the basis of the sap flow rate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cultivation system and an illuminance control method in the cultivation system.

  BACKGROUND ART Conventionally, as a cultivation system, a cultivation system that controls illuminance in a greenhouse by opening and closing a light-blocking curtain provided in a greenhouse has been proposed (for example, see Patent Literature 1).

  The cultivation system includes a pyranometer for measuring the solar radiation intensity of the greenhouse, and the computer controls the light-shielding curtain device so that the maximum value of the solar radiation intensity of the cultivation unit in the past 15 minutes is equal to or less than a preset maximum solar radiation intensity. Had control. The light-shielding curtain device combines two layers of light-shielding curtains having different light-shielding ratios, and performs control such that each of the light-shielding curtains is opened or closed in one of four light-shielding states.

  Here, in the conventional cultivation system as described above, it was only possible to control the light-shielding curtain to any one of four types of light-shielding states based on the solar radiation intensity. For this reason, there has been a case where an inconvenience that the illuminance cannot always be controlled in accordance with the state of the plant to be cultivated occurs.

JP-A-8-103173

  The present invention has been made in view of the above-described problems, and provides a technique capable of controlling illuminance to be more appropriate in a cultivation system for cultivating a plant, according to a state of the cultivated plant. The purpose is to do.

The present invention for solving the above problems,
A water flow measuring means for measuring the flow of water in the body of the plant,
An illuminance control unit that controls the illuminance of light emitted from the light source to the plant, based on the flow rate of water in the body of the plant, measured by the moisture flow measurement unit,
It is a cultivation system characterized by comprising.

  According to the present invention, the illuminance of light emitted from the light source to the plant is controlled based on the flow rate of water in the plant, which has a strong correlation with the photosynthesis rate of the plant to be cultivated. Depending on the state, it is possible to control the illuminance to be more appropriate, in which photosynthesis is performed more actively.

Further, in the present invention, the illuminance control means for controlling the illuminance by controlling an input operation amount, the water content in the body of the plant measured by the water flow rate measurement means with respect to a change in the operation amount. The change ratio of the flow rate of the first is the first ratio,
The illuminance may be controlled based on the first ratio.

According to this, since the illuminance is controlled based on the first ratio including the operation amount of the illuminance control means, the photosynthesis of the cultivated plant is performed based on the relationship between the illuminance and the flow rate of water in the plant. The state of the speed can be grasped more accurately. Therefore, according to the state of the plant, it is possible to control the illuminance to be more appropriate, in which photosynthesis is performed more actively.

Further, in the present invention, the illuminance control means includes:
Whether to increase, maintain, or decrease the illuminance may be determined based on whether the first ratio is positive, negative, or zero.

  Here, the case where the first ratio is 0 is not limited to the case where the numerical value is strictly 0, but includes a certain width in a positive or negative range. Even when the first ratio is positive or negative, it does not indicate a region where only 0 is strictly excluded as a numerical value. Note that the sign of the first ratio is different depending on whether the direction of change is based on the increasing direction or the decreasing direction, but which one should be set as appropriate is appropriate.

Further, in the present invention, an illuminance measuring unit for measuring the illuminance,
The illuminance control means,
For the change in the illuminance measured by the illuminance measuring means, the ratio of the change in the flow rate of water in the body of the plant measured by the water flow rate measuring means as a second ratio,
The illuminance may be controlled based on the second ratio.

  According to this, the illuminance is controlled based on the second ratio including the illuminance measured by the illuminance measuring means. Therefore, the plant to be cultivated based on the relationship between the illuminance and the flow rate of water in the plant body is controlled. The state of the photosynthetic speed of the object can be grasped more accurately. Therefore, according to the state of the plant, it is possible to control the illuminance to be more appropriate, in which photosynthesis is performed more actively.

Further, in the present invention, the illuminance control means includes:
Whether to increase, maintain, or decrease the illuminance may be determined based on whether the second ratio is positive, negative, or zero.

  Here, the case where the second ratio is 0 is not limited to the case where the numerical value is strictly 0, but includes a certain width in a positive or negative range. Even when the second ratio is positive or negative, it does not indicate a region where only 0 is strictly excluded as a numerical value. The sign of the second ratio is different depending on whether the direction of the change is based on the increasing direction or the decreasing direction, but it may be set appropriately as to which one is used as the reference.

Further, in the present invention, a saturation acquisition means for acquiring the saturation of the air around the plant,
The illuminance control means,
The third ratio is a ratio of the flow rate of water in the body of the plant measured by the water flow rate measuring means to the saturation obtained by the saturation obtaining means,
A ratio of a change in the third ratio to a change in the illuminance measured by the illuminance measuring unit is a fourth ratio,
The illuminance may be controlled based on the fourth ratio.

  According to this, the illuminance is controlled based on the ratio of the change in the third ratio to the change in the illuminance, which more accurately reflects the state of the photosynthetic rate of the cultivated plant. The illuminance can be controlled based on a more accurate grasp of the state of the photosynthetic speed of the camera. Therefore, according to the state of the plant, it is possible to control the illuminance to be more appropriate, in which photosynthesis is performed more actively.

Further, in the present invention, the illuminance control means includes:
Whether to increase, maintain, or decrease the illuminance may be determined based on whether the fourth ratio is positive, negative, or zero.

  Here, the case where the fourth ratio is 0 is not limited to the case where the fourth ratio is strictly 0, but includes a certain width in a positive or negative range. The case where the fourth ratio is positive or negative does not indicate a region where only 0 is strictly excluded as a numerical value. The sign of the fourth ratio is different depending on the case where the direction of change is based on the increasing direction and the case where the direction of change is based on the decreasing direction.

  Further, in the present invention, the water flow rate measuring means may be a sap flow rate measuring means for measuring a flow rate of sap flowing in the vessel of the plant.

Further, in the present invention, the illuminance control means includes:
A light blocking member that blocks an optical path of light incident on the plant from the light source,
Opening degree control means for controlling an opening ratio of the optical path by the light shielding member,
And the illuminance may be controlled by controlling the open ratio.

According to this, when using light from a light source outside the cultivation system such as the sun, by controlling the opening ratio of the light-blocking member, depending on the state of the plant, photosynthesis is more actively performed, Illuminance can be controlled to be more appropriate.
The open ratio of the light-blocking member is not limited to the ratio of the open portion of the optical path of the incident light, and may be the ratio of the portion that is not opened and is blocked.

Further, in the present invention, the illuminance control means includes:
The illuminance may be controlled by controlling an input to the light source.

  According to this, in the case where the cultivation system has a light source capable of controlling the output according to the input, the photosynthesis is more actively performed according to the state of the plant by controlling the input of the light source. Illuminance can be controlled.

Further, the present invention is a method for controlling the illuminance of light emitted from a light source to the plant in a cultivation system for growing the plant,
When changing the illuminance, the step of acquiring the amount of change in the flow rate of water in the body of the plant,
Controlling the illuminance based on the amount of change;
Is an illuminance control method in a cultivation system including

  According to this, when the illuminance is changed, the illuminance is controlled based on the amount of change in the flow rate of the water in the plant, so that the flow rate of the water in the plant having a strong relationship with the illuminance and the photosynthetic rate is controlled. Based on the relationship, the state of the photosynthetic rate of the plant to be cultivated can be more accurately grasped. Therefore, according to the state of the plant, it is possible to control the illuminance to be more appropriate, in which photosynthesis is performed more actively.

Further, the present invention is a method for controlling the illuminance by controlling an operation amount input to illuminance control means for controlling the illuminance of light emitted from the light source to the plant in a cultivation system for growing a plant,
Obtaining a change amount of the operation amount;
When the manipulated variable is changed, a step of acquiring a change in the flow rate of water in the body of the plant,
A first ratio, which is a ratio of a change amount of water content in the body of the plant to a change amount of the operation amount;
Obtaining the ratio of
Controlling the illuminance based on the first ratio;
Is an illuminance control method in a cultivation system including

  According to this, when the amount of operation of the illuminance control means is changed, the illuminance is controlled based on the amount of change in the flow rate of water in the plant body. Based on the relationship with the flow rate of water in the body, it is possible to more accurately grasp the state of the photosynthetic rate of the plant to be cultivated. Therefore, according to the state of the plant, it is possible to control the illuminance to be more appropriate, in which photosynthesis is performed more actively.

Controlling the illuminance based on the first ratio,
Determining whether the first ratio is positive, negative or zero;
Determining whether to increase, maintain, or decrease the illuminance based on whether the first ratio is positive, negative, or zero;
May be included.

  Here, when the first ratio is 0, it is not limited to the case where the first ratio is strictly 0, but includes a certain width in the positive or negative range. Even when the first ratio is positive or negative, it does not indicate a region where only 0 is strictly excluded as a numerical value. Note that the sign of the first ratio is different depending on whether the direction of change is based on the increasing direction or the decreasing direction, but which one should be set as appropriate is appropriate.

Further, the present invention is a method for controlling the illuminance of light emitted from a light source to the plant in a cultivation system for growing the plant,
Measuring the illuminance;
Obtaining a flow rate of water in the body of the plant,
Acquiring a second ratio that is a ratio of a change in a flow rate of water in the body of the plant to a change in the illuminance;
Controlling the illuminance based on the second ratio;
Is an illuminance control method in a cultivation system including

  According to the present invention, the illuminance is controlled based on the second ratio, which is the ratio of the change in the flow rate of water in the plant to the change in the illuminance. Based on the relationship with the flow rate of water in the body, it is possible to more accurately grasp the state of the photosynthetic rate of the plant to be cultivated. Therefore, according to the state of the plant, it is possible to control the illuminance to be more appropriate, in which photosynthesis is performed more actively.

In the present invention, the step of controlling the illuminance based on the second ratio includes:
Determining whether the second ratio is positive, negative or zero;
Determining whether to increase, maintain, or decrease the illuminance based on whether the second ratio is positive, negative, or zero;
May be included.

  Here, when the second ratio is 0, it is not limited to the case where the second ratio is strictly 0, but includes a certain width in a positive or negative range. Even when the second ratio is positive or negative, it does not indicate a region where only 0 is strictly excluded as a numerical value. The sign of the second ratio is different depending on whether the direction of the change is based on the increasing direction or the decreasing direction, but it may be set appropriately as to which one is used as the reference.

Further, the present invention is a method for controlling the illuminance of light emitted from a light source to the plant in a cultivation system for growing the plant,
The third ratio is a ratio of the flow rate of water in the body of the plant to the saturation of the air around the plant,
Obtaining a fourth ratio that is a ratio of a change in the third ratio to a change in the illuminance;
Controlling the illuminance based on the fourth ratio;
Is an illuminance control method in a cultivation system including

  According to this, the illuminance is controlled based on the ratio of the change in the third ratio to the change in the illuminance, which more accurately reflects the state of the photosynthetic rate of the cultivated plant. The illuminance can be controlled based on a more accurate grasp of the state of the photosynthetic speed of the camera. Therefore, according to the state of the plant, it is possible to control the illuminance to be more appropriate, in which photosynthesis is performed more actively.

In the present invention, the step of controlling the illuminance based on the fourth ratio includes:
Determining whether the fourth ratio is positive, negative or zero;
Determining whether to increase, maintain, or decrease the illuminance based on whether the fourth ratio is positive, negative, or zero;
May be included.

  Here, when the fourth ratio is 0, it is not limited to the case where the fourth ratio is strictly 0, but includes a certain width between positive and negative. The case where the fourth ratio is positive or negative does not indicate a region where only 0 is strictly excluded as a numerical value. The sign of the fourth ratio is different depending on the case where the direction of change is based on the increasing direction and the case where the direction of change is based on the decreasing direction.

  ADVANTAGE OF THE INVENTION According to this invention, in the cultivation system which cultivates a plant, it becomes possible to provide the technique which can control more appropriate illuminance according to the state of the plant cultivated.

It is a figure showing the schematic structure of the cultivation system in Example 1 of the present invention. It is a graph which shows the relationship between illuminance and photosynthesis speed. It is a graph which shows the relationship between illuminance and sap flow velocity. 4 is a flowchart illustrating a method for controlling illuminance in Embodiment 1 of the present invention. It is a figure showing the schematic structure of the cultivation system in Example 2 of the present invention. 9 is a flowchart illustrating a method for controlling illuminance in Embodiment 2 of the present invention. It is a figure showing the schematic structure of the cultivation system in Example 3 of the present invention. 9 is a flowchart illustrating a method for controlling illuminance in Embodiment 3 of the present invention. It is a figure showing the schematic structure of the cultivation system in Example 4 of the present invention. 11 is a flowchart illustrating a method for controlling illuminance in Embodiment 4 of the present invention.

[Application example]
Hereinafter, application examples of the present invention will be described with reference to the drawings. The present invention is applied to, for example, a cultivation system 1 as shown in FIG. The cultivation system 1 illuminates the plant 2 to be cultivated with the illuminance of the light emitted from the sun 4 as a light source by using a light-shielding curtain 5 as a shielding member for shielding an incident optical path and an opening ratio of the light-shielding curtain 5. A certain degree of opening is controlled based on the sap flow rate measured by the sap flow sensor 7 which is a water flow rate measuring means for measuring the flow rate of water in the body of the plant 2. The flow rate by the water flow rate measuring means includes not only the flow rate itself but also a flow rate which is a flow rate per a predetermined time. In the following embodiments, a sap flow sensor for measuring a sap flow rate will be described as the water flow rate measuring means.

  As shown in FIG. 2, the illuminance and the photosynthetic rate in a plant are such that as the illuminance increases, the photosynthetic rate increases, and at a certain illuminance, the change in the photosynthetic rate becomes constant. Follow change. The photosynthetic rate is an index indicating the activity of photosynthesis, and varies depending on conditions of the plant itself, such as the growth stage of the plant, and environmental conditions, such as the concentration of carbon dioxide. For this reason, in order to cultivate in a state where photosynthesis is performed more actively, it is necessary to control the illuminance of the light applied to the plant 2 so that the illuminance at which the photosynthesis rate is the highest in FIG. 2 (optimum illuminance). There is.

  At this time, the sap flow rate, which is the flow rate of water flowing in the tract of the plant 2, has a strong correlation with the photosynthetic rate. This is because when the plant 2 tries to take in carbon dioxide for photosynthesis from the surrounding air and opens pores, water in the body of the plant 2 evaporates through the pores, and the amount of transpiration correlates with the sap flow rate. by.

  In the cultivation system shown in FIG. 1, the opening degree of the light-shielding curtain 5 is controlled based on the sap flow rate measured by the sap flow sensor 7, regardless of the fluctuation of the condition of the plant 2 itself or the environmental condition. In addition, the illuminance can be appropriately controlled in real time so that the illuminance at which photosynthesis is more actively performed.

Further, as in the second embodiment shown in FIG. 5, the system 21 further includes an illuminance sensor 10 as illuminance measuring means, and controls the opening degree of the light-shielding curtain 5 based on a ratio of a change in the sap flow velocity to a change in the illuminance. Also applicable to Further, as in Embodiment 3 shown in FIG. 7, the apparatus further includes a humidity sensor 11 serving as a humidity measuring unit and a temperature sensor 12 serving as a temperature measuring unit. The present invention can also be applied to a cultivation system 31 that controls the degree of opening of the light-blocking curtain 5 based on the ratio to the change.
The present invention can be applied to a system for controlling the output of the artificial light source 13 as in Embodiment 4 shown in FIG.

[Example 1]
Hereinafter, the cultivation system according to the first embodiment of the present invention will be described in more detail with reference to the drawings.

<System configuration>
FIG. 1 shows a schematic configuration of the cultivation system according to the first embodiment. The cultivation system 1 includes a house 3 that houses a plant 2. In addition, the cultivation system 1 includes a light-shielding curtain 5 that is opened and closed in order to shield a part or all of the light emitted from the sun 4 as a light source to the plant 2 and control the amount of incident light. In addition, the cultivation system 1 includes a diffusion film 6 that diffuses a light beam applied to the plant 2 via the light-shielding curtain 5. The cultivation system 1 further includes a sap flow sensor 7 that measures the sap flow rate of the plant 2 and a control device 8 that controls the opening of the light-blocking curtain 5 based on the sap flow rate measured by the sap flow sensor 7. .
Although only one plant 2 is shown in FIG. 1, this is a schematic example, and the number of plants 2 cultivated in the house 3 is not limited. Plant 2 is cultivated.

The light-blocking curtain 5 is a sheet-like member that is expanded and closed, and is contracted or wound up and opened. The degree of opening of the light-blocking curtain 5 is not limited to the two states of fully open and fully closed, and can be changed in a stepless manner from fully open to fully closed. As described later, the opening degree is changed by causing the light shielding curtain 5 to perform an opening operation or a closing operation for a specified time. Further, the method of changing the opening degree of the light-shielding curtain 5 is not limited to this, and may be set so that it can be changed stepwise from fully open to fully closed. The light-blocking curtain 5 is wirelessly connected to the control device 8, receives a control signal for setting the opening of the light-blocking curtain 5 from the control device 8, and transmits information indicating the current opening as necessary. It has a transmission / reception function for transmitting to The light-blocking member is not limited to such a light-blocking curtain 5, but may be a blind that includes a plurality of louvers and controls the amount of incidence by the angle of the louvers, or controls the amount of incidence by changing the transparency of the liquid crystal. It may be a liquid crystal panel. Here, the light shielding curtain 5 corresponds to a light shielding member, the control device 8 corresponds to a light shielding control unit, and the light shielding curtain 5 and the control device 8 correspond to an illuminance control unit.

  The diffusion film 6 has a function of diffusing the incident light so that the illuminance distribution of the light applied to the plant 2 cultivated in the house 3 becomes uniform. The diffusion film 6 may be a member such as a roof, a ceiling, a side wall, or the like as the diffusion film 6, or the diffusion film 6 may be attached to the component. The member is not limited to a film-like member as long as it has a function of diffusing incident light rays.

  In FIG. 1, the sap flow sensor 7 is mounted on the stem 2a of the plant 2, but the mounting site of the sap flow sensor 7 is not limited to the stem 2a, and the leaf 2b or another part may be selected. The plant 2 to which the sap flow sensor 7 is attached can be appropriately selected from the large number of plants 2. The sap flow sensor 7 may be mounted on all the plants 2 to be cultivated, or the sap flow sensor 7 may be mounted on a plurality of selected plants 2. Here, the sap flow sensor 7 corresponds to the water flow rate measuring means and the sap flow rate measuring means.

  Various methods such as a stem heat balance method, a heat pulse method, and a heat dissipation method (Granier method) have been proposed as methods for measuring the sap flow velocity. It can be appropriately selected according to conditions such as the type and the site. The sap flow sensor 7 is wirelessly connected to the control device 8 and has a transmission / reception function of transmitting a measurement result to the control device 8 and receiving a control signal from the control device 8 as necessary.

  As the control device 8, for example, a PLC (programmable logic controller) in which a program for controlling the opening degree of the light-shielding curtain 5 based on the measurement result of the sap flow sensor 7 is incorporated in advance can be used. The control device 8 is not limited to the PLC, and may be a PC (personal computer) that reads a program for controlling the opening of the light shielding curtain 5 stored in a storage device such as a ROM and executes the program on the CPU. The control device 8 includes a communication unit that performs transmission and reception between the sap flow sensor 7 and the light shielding curtain 5. The control device 8 and the sap flow sensor 7, the light-shielding curtain 5, and the like are not limited to being connected wirelessly, and may be connected by wire.

  The house 3 is provided with various devices for adjusting the cultivation environment, such as a watering device for supplying water to the plant 2 via a medium or the like, a temperature adjusting device for cooling and / or heating the house 3, and a ventilating device. However, description of these devices is omitted.

  Generally, it is known that the illuminance of light applied to a plant and the photosynthetic rate of the plant have a relationship shown in a light-photosynthesis curve in FIG. Of course, various conditions such as carbon dioxide concentration, temperature, and humidity also affect the photosynthetic rate of the plant, but here, it is assumed that these conditions are constant. As shown in FIG. 2, as the illuminance increases, the photosynthesis speed also increases, but as the illuminance further increases, the photosynthesis speed decreases. As described above, assuming that other conditions are constant, the photosynthesis speed becomes maximum at a certain illuminance. Therefore, if the light flux incident from the light source is controlled so as to approach the illuminance at which the photosynthetic rate becomes the maximum, photosynthesis is most actively performed, the growth of the plant proceeds, and the yield is expected to increase. .

  In photosynthesis, plants absorb water contained in carbon dioxide from pores on the surface to organic matter by water absorbed by a medium or soil via roots and transported by vasculature and light energy. By opening the pores to absorb carbon dioxide for photosynthesis, water in the plant also evaporates through the open pores. Here, the sap flow transported through the vessel includes water that is degraded by photosynthesis and water that evaporates through the pores, which are measured by the sap flow sensor 7. When photosynthesis is active and the amount of carbon dioxide absorbed per hour increases, the amount of water evaporating through open pores also increases, and the sap flow rate increases, so there is a strong correlation between photosynthetic rate and sap flow rate. It is known that there is.

  Therefore, as shown in FIG. 3, the relationship between the illuminance and the sap flow velocity is similar to the relationship between the illuminance and the photosynthetic rate, and the sap flow velocity increases as the illuminance increases, and the illuminance further increases beyond a certain illuminance. Then, the curve follows a change in which the sap flow velocity decreases. From such a relationship between the illuminance and the sap flow rate, the sap flow sensor 7 measures the sap flow rate and controls the opening of the light-blocking curtain so as to approach the illuminance at which the sap flow rate becomes maximum, so that photosynthesis becomes more active. Optimum illuminance can be obtained. Such an optimum illuminance itself varies depending on the condition of the plant 2 itself, such as the type of the plant 2 and the growth stage, or other environmental conditions such as the concentration of carbon dioxide. , The optimum illuminance can always be realized in real time.

<Control method>
FIG. 4 is a flowchart illustrating a method for controlling the light-blocking curtain according to the first embodiment.
In step 1 (referred to as S1 in the figure; the same applies to the following description), a control signal is transmitted from the control device 8 to the light shielding curtain 5, and the light shielding curtain 5 is moved to a predetermined initial position. In step 2, the sap flow velocity is measured by the sap flow sensor 7. In the control device 8, in step 3, i = 0 is set, and in step 4, the opening degree of the light shielding curtain 5 is substituted into a variable b (i). Here, the opening degree of the light-shielding curtain 5 corresponds to an operation amount input to the light-shielding curtain 5 and the control device 8 corresponding to the illuminance control unit. Regarding the opening degree of the light shielding curtain 5, for example, the opening degree when the light shielding curtain 5 is completely closed is set to 0 (%), and the opening degree when the light shielding curtain 5 is fully opened is set to 100 (%). In step 5, the sap flow rate measured in step 2 is substituted for the variable a (i) and stored. In step 6, a control signal from the control device 8 to the light shielding curtain 5 is transmitted, and the opening operation of the light shielding curtain 5 is performed for T seconds. The opening operation of the light-shielding curtain 5 is performed in order to detect whether the direction of the change in the sap flow rate is increasing or decreasing or constant, based on a change in illuminance caused by a change in the opening degree of the light-shielding curtain 5 in an initial stage of control. Things. Therefore, the time T of the opening operation may be appropriately selected such that such a significant change in the sap flow rate can be detected. In step 7, the sap flow sensor 7 measures the sap flow rate in a state after the opening operation of the light shielding curtain 5. In the control device 8, in step 8, i = i + 1, and in step 9, the opening degree of the light shielding curtain 5 after performing the opening operation for T seconds in step 6 is substituted into a variable b (i). In step 10, the sap flow rate measured in step 7 is substituted for the variable a (i) and stored. In step 11, the control device 8 sets k1 = {a (i) -a (i-1)} / {b (i) -b (i-1)} as the photosynthetic coefficient k1 for evaluating the photosynthetic rate of the plant 2. Is calculated. Here, k1 corresponds to the first ratio. In step 12, the control device 8 determines the magnitude relation between k1 and 0 calculated in step 11. In step 12, illuminance control is determined based on whether k1 is positive, negative, or zero. Here, if the determination in step 12 is k1> 0, the process proceeds to step 13 in which a control signal from the control device 8 to the light shielding curtain 5 is transmitted, and the opening operation of the light shielding curtain 5 is performed in order to increase the illuminance. Perform for t1 seconds. If the determination in step 12 is k1 = 0, the process proceeds to step 14, where a control signal from the control device 8 to the light-shielding curtain 5 is transmitted, and the light-shielding curtain 5 is not operated to maintain the illuminance. If the determination in step 12 is k1 <0, the process proceeds to step 15, where a control signal from the control device 8 to the light-shielding curtain 5 is transmitted, and the closing operation of the light-shielding curtain 5 is performed for t2 seconds to reduce the illuminance. Let Step 13, 14 or 1
After 5, the process returns to step 7, and the processing from step 7 to step 13, 14, or 15 is repeated.
Here, the case of k1 = 0 (the same applies to k2, k3, and k4 described later) is not limited to the case where the numerical value is strictly 0, but includes a certain width in a positive or negative range. Even when the third ratio is positive or negative, it does not indicate a region where only 0 is strictly excluded as a numerical value.
The above-described opening degree control of the light-blocking curtain 5 appropriately sets an end condition so that the control device 8 ends when the k1 satisfies a predetermined condition or when predetermined timing information such as a sunset time is acquired. be able to. In addition, the start condition of the above-described opening control of the light-blocking curtain 5 can be appropriately set so as to start when predetermined timing information such as sunrise time is acquired.
In step 14, the control signal may not be transmitted from the control device 8 to the light-shielding curtain 5, so that the light-shielding curtain 5 may not be operated. The time t1 of the opening operation of the light shielding curtain 5 when k1> 0 in step 13 and the time t2 of the closing operation of the light shielding curtain 5 when k1 <0 in step 15 are set as t1 = t2. Or t1 ≠ t2. In the control process, the values of t1 and t2 may be changed according to the absolute value of k1. For example, the values of t1 and t2 may be reduced as the absolute value of k1 decreases.
As described above, the sap flow rate having a strong correlation with the photosynthetic rate is measured by the sap flow sensor 7, and the opening degree of the light-shielding curtain 5 is maintained so that the inside of the house 3 is maintained at an illuminance at which the sap flow rate is constant. , The optimum illuminance at which photosynthesis becomes active can be realized in real time.

[Example 2]
Hereinafter, the cultivation system 21 according to the second embodiment of the present invention will be described with reference to FIG.

<System configuration>
The cultivation system 21 according to the second embodiment includes the illuminance sensor 10 that measures the illuminance in the house 3 in addition to the cultivation system 1 according to the first embodiment. About the structure common to the cultivation system 1 which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted. The illuminance sensor 10 is disposed at an appropriate position in the house 3 where the illuminance of light applied to the plant 2 can be measured. FIG. 5 is an example, and the installation position and the number of the illuminance sensors 10 can be set as appropriate. One may be installed at a position representative of the illuminance distribution in the house 3, or the inside of the house 3 may be divided into a plurality of areas, and the illuminance sensor 10 may be installed for each area. Further, an illuminance sensor 10 corresponding to each sap flow sensor 7 may be provided. Here, the illuminance sensor 10 corresponds to an illuminance measurement unit.

  As described in the first embodiment, the illuminance and the sap flow velocity have a relationship as shown in FIG. Here, the sap flow velocity is a, the illuminance is b, and the photosynthetic coefficient k2 for evaluating the photosynthetic rate is determined as k2 = Δa / Δb. Then, k2> 0 in a region where the sap flow speed increases as the illuminance increases, k2 = 0 in a region where the sap flow speed becomes maximum with the increase in the illuminance, and k2> 0 in a region where the sap flow speed decreases with the increase in the illuminance. <0. Therefore, the control device 8 calculates the photosynthetic coefficient k2 from the measurement result of the sap flow sensor 7 and the measurement result of the illuminance sensor 10, determines the magnitude relationship between k2 and 0, and accordingly opens the light shielding curtain 5. By controlling the degree, the illuminance in the house 3 can be made the optimum illuminance at which photosynthesis of the plant 2 becomes active in real time.

<Control method>
FIG. 6 is a flowchart illustrating a method for controlling the light-blocking curtain 5 according to the second embodiment.
In step 21, the sap flow rate of the plant 2 is measured by the sap flow sensor 7. Then, in step 22, the illuminance in the house 3 is measured by the illuminance sensor 10. In step 23, the controller 8 calculates the photosynthetic coefficient k2 = Δa / Δb from the measured value a of the sap flow velocity in step 21 and the measured value b of the illuminance in step 22. Here, k2 corresponds to the second ratio. The measurement of the sap flow velocity in step 21 and the measurement of the illuminance in step 22 are performed in parallel, but the sampling timings need not necessarily be the same. In the overlapping time width, based on the information obtained by processing the measurement values sampled a plurality of times, the corresponding change amount of the sap flow velocity and the change amount of the illuminance may be calculated, and the photosynthesis coefficient k2 may be calculated from these. Even when a plurality of sap flow sensors 7 and illuminance sensors 10 are provided, processing such as averaging is performed on each measurement result. In step 24, the control device 8 determines the magnitude relationship between the calculated photosynthetic coefficient k2 and 0. In step 24, illuminance control is determined based on whether k2 is positive, negative, or zero. Here, if it is determined in step 24 that k2> 0, in step 25, a control signal is transmitted from the control device 8 to the light-shielding curtain 5, and the opening operation of the light-shielding curtain 5 is performed to increase the illuminance. Perform for t3 seconds. If it is determined in step 24 that k2 = 0, in step 26, a control signal is transmitted from the control device 8 to the light shielding curtain 5, and the light shielding curtain 5 is not operated in order to maintain the illuminance. If it is determined in step 24 that k2 <0, in step 27, a control signal is transmitted from the control device 8 to the light-shielding curtain 5, and the closing operation of the light-shielding curtain 5 is performed for t4 seconds to reduce the illuminance. Let it do. After performing the processing of steps 25 to 27, the process returns to step 21 and step 22, and thereafter the processing of steps 21 to 27 is repeated at predetermined time intervals.
In step 26, the control signal may not be transmitted from the control device 8 to the light-blocking curtain 5, so that the light-blocking curtain 5 may not be operated. Further, the time t3 seconds of the opening operation of the light shielding curtain 5 when k2> 0 in step 25 and the time t4 of the closing operation of the light shielding curtain 5 when k2 <0 in step 27 are set as t3 = t4. Or t3 ≠ t4. In the control process, the values of t3 and t4 may be changed according to the magnitude of the absolute value of k2. For example, the values of t3 and t4 may be reduced as the absolute value of k2 decreases.

[Example 3]
Hereinafter, the cultivation system 31 according to the third embodiment of the present invention will be described with reference to FIG.

<System configuration>
The cultivation system 31 according to the third embodiment includes, in addition to the cultivation system 21 according to the second embodiment, the humidity sensor 11 that measures the humidity inside the house 3 and the temperature sensor 12 that measures the temperature inside the house 3. About the structure common to the cultivation system 1 which concerns on Example 1, and the cultivation system 21 which concerns on Example 2, the same code | symbol is attached | subjected and description is abbreviate | omitted. The humidity sensor 11 and the temperature sensor 12 are arranged at appropriate positions in the house 3. FIG. 7 is an example, and the installation position and the number of the humidity sensor 11 and the temperature sensor 12 can be set as appropriate. One may be installed at a position representative of the humidity distribution and the temperature distribution in the house 3, or the inside of the house 3 is divided into a plurality of areas, and the humidity sensor 11 and the temperature sensor 12 are installed for each area. May be. Further, a humidity sensor 11 and a temperature sensor 12 corresponding to each sap flow sensor 7 may be provided. Instead of measuring humidity with the humidity sensor 11 and temperature with the temperature sensor 12, a temperature and humidity sensor that can measure both humidity and temperature may be used.

In Example 2, the photosynthetic coefficient k2 defined by Δa / Δb with respect to the sap flow rate a and the illuminance b was used as the photosynthetic coefficient for evaluating the photosynthetic rate. In the third embodiment, a new photosynthesis coefficient k3 for evaluating the photosynthesis speed is introduced. In order to more accurately evaluate the photosynthetic rate, it is necessary to consider the saturation (the difference between the saturated water vapor pressure in the air at a certain temperature and the actually contained water vapor pressure). Therefore, here, the saturation is defined as v, and the pore conductivity c (also referred to as pore conductivity or pore conductance) c defined by c = a / v is used. The saturation v can be derived from the temperature and the relative humidity and saturated water vapor pressure at that temperature. Actually, the stomatal conductance c is represented as α (a / v) including a coefficient α determined by the area of the leaf, the health state, and the like. Here, the explanation will be made assuming that α is a constant 1. Using the pore conductivity c, the photosynthetic coefficient k3 is set to k3 = Δc / Δb. Therefore, the control device 8 calculates the photosynthetic coefficient k3 from the measurement results of the sap flow sensor 7, the measurement results of the illuminance sensor 10, and the measurement results of the humidity sensor 11 and the temperature sensor 12, and determines the magnitude relationship between k3 and 0. Judgment is made, and the degree of opening of the light shielding curtain 5 is controlled accordingly. Thereby, the illuminance in the house 3 can be made the optimal illuminance at which photosynthesis of the plant 2 becomes active in real time. Here, the pore conductivity c corresponds to the third ratio, and the photosynthetic coefficient k3 corresponds to the fourth ratio. Further, a part of the humidity sensor 11, the temperature sensor 12, and a part of the control device 8 having a function of deriving the saturation from the measurement results thereof correspond to the saturation obtaining means.

<Control method>
FIG. 8 is a flowchart illustrating a method for controlling the light-blocking curtain according to the third embodiment.
In step 31, the sap flow rate of the plant 2 is measured by the sap flow sensor 7. In step 32, the illuminance in the house 3 is measured by the illuminance sensor. In step 33, the humidity inside the house 3 is measured by the humidity sensor 11, and the temperature inside the house 3 is measured by the temperature sensor 12, respectively. In step 34, in the control device 8 having received the respective measurement results from the sap flow sensor 7, the illuminance sensor 10, the humidity sensor 11, and the temperature sensor 12, first, from the measurement results of the humidity sensor 11 and the temperature sensor 12, the saturation v Is calculated. Here, the control device 8 acquires the saturated steam pressure at the temperature measured by the temperature sensor 12 by using a table of the temperature and the saturated steam pressure stored in advance or a calculation formula for calculating the saturated steam pressure from the temperature. The saturation v is determined from the saturated water vapor pressure and the relative humidity which is the measurement result of the humidity sensor 11. Then, the control device 8 calculates the stomatal conductance c = a / v from the saturation v and the sap flow rate a, and calculates the photosynthetic coefficient k3 = Δc / Δb from the illuminance b which is the measurement result of the illuminance sensor 10. . The measurement of the sap flow velocity in step 31, the measurement of the illuminance in step 32, and the measurement of the humidity and temperature in step 33 are performed in parallel, but the sampling timings need not always be the same. In the overlapping time width, based on the information obtained by processing the measurement values sampled a plurality of times, the corresponding amount of change in saturation and the amount of change in illuminance may be calculated, and the photosynthesis coefficient k3 may be calculated from these.
In step 35, the magnitude relationship between the photosynthesis coefficient k3 calculated by the control device 8 and 0 is determined. In step 35, the control of the illuminance is determined based on whether k3 is positive, negative or 0. Here, if it is determined that k3> 0, in step 36, a control signal is transmitted from the control device 8 to the light-shielding curtain 5, and the opening operation of the light-shielding curtain 5 is performed for t5 seconds to increase the illuminance. . When it is determined that k3 = 0, in step 37, a control signal is transmitted from the control device 8 to the light shielding curtain 5, and the light shielding curtain 5 is not operated in order to maintain the illuminance. When it is determined that k3 <0, in step 38, a control signal is transmitted from the control device 8 to the light-shielding curtain 5, and the closing operation of the light-shielding curtain 5 is performed for t6 seconds in order to reduce the illuminance. After performing the processes of steps 36 to 38, the process returns to steps 31, 32 and 33, and thereafter the processes of steps 31 to 38 are repeated at predetermined time intervals.
In Step 37, the control signal may not be transmitted from the control device 8 to the light-shielding curtain 5, so that the light-shielding curtain 5 may not be operated. Further, the time t5 of the opening operation of the light shielding curtain 5 when k3> 0 in step 36 and the time t6 of the closing operation of the light shielding curtain 5 when k3 <0 in step 38 are set as t5 = t6. Or t5 ≠ t6. In the control process, the values of t5 and t6 may be changed according to the magnitude of the absolute value of k3. For example, the values of t5 and t6 may be reduced as the absolute value of k3 decreases.

[Example 4]
Hereinafter, the cultivation system 41 according to the fourth embodiment of the present invention will be described with reference to FIG.

<System configuration>
The cultivation system 41 according to the fourth embodiment uses the light source 13 such as an LED that emits artificial light instead of the sun 4 that is the light source in the cultivation system 1 according to the first embodiment. For this reason, the cultivation system 41 according to the fourth embodiment does not include the light-blocking curtain 5 that adjusts the illuminance of the light beam irradiated on the plant 2 in the house 3. 9 shows only one plant 2 since it is a schematic example, but a plurality of plants 2... 2 are actually arranged in the house 3. The cultivation system 1 according to the first embodiment uses the diffusion film 6 in order to make the illuminance distribution of the light rays to the plurality of plants 2,... 2 uniform. However, in the cultivation system 41 according to the fourth embodiment, by arranging the plurality of light sources 13,... 13 at appropriate positions in the house 3, the illuminance distribution of light rays to the plurality of plants 2,. Therefore, the diffusion film 6 is not provided. The cultivation system 41 has the same configuration as the cultivation system 1 except that the cultivation system 41 does not include the light-shielding curtain 5 and the diffusion film 6. About the structure common to the cultivation system 1 which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted. However, in the cultivation system 41, the control device 8 controls the luminous intensity of the light source 13 instead of controlling the opening of the light-shielding curtain 5. In the cultivation system 41 described above, the diffusion film 6 is not provided, but the diffusion film 6 may be used to diffuse the light from the light source 13. Here, the control device 8 corresponds to illuminance control means.
As shown in FIG. 3, the sap flow rate increases in accordance with the increase in the illuminance, and the curve of the sap flow rate changes at a certain illuminance, and the sap flow rate decreases as the illuminance further increases. From such a relationship between the illuminance and the sap flow velocity, the sap flow rate is measured by the sap flow sensor 7 and the luminous intensity of the light source 13 is controlled so as to approach the illuminance at which the sap flow velocity becomes maximum, so that photosynthesis is more active. Illuminance can be obtained. Such an optimum illuminance itself varies depending on the condition of the plant 2 itself, such as the type of the plant 2 and the growth stage, or other environmental conditions such as the concentration of carbon dioxide. , The optimum illuminance can always be realized in real time.

<Control method>
FIG. 10 is a flowchart illustrating a method for controlling the light source 13 according to the fourth embodiment.
In step 41, a control signal is transmitted from the control device to the light source 13, and the input current of the light source 13 is set to an initial value I0. In this embodiment, a case where the input current to the light source 13 is controlled in order to control the light intensity of the light source, and thus the illuminance of the light applied to the plant 2 will be described as an example. However, the light intensity of the light source 13 is controlled. The input operation amount can be appropriately selected according to the light source 13 such as voltage and power. In step 42, the sap flow rate is measured by the sap flow sensor 7. In the control device 8, in step 43, i = 0 is set. In step 44, the input current value to the light source 13 (here, the initial value I0) is substituted for a variable I (i). In step 45, the sap flow rate measured in step 42 is substituted for a (i) and stored. In step 46, a control signal from the control device 8 to the light source 13 is transmitted, and the input current value to the light source 13 is set to I0 + ΔI. This change of the input current value to the light source is performed in order to detect whether the direction of the change in the sap flow rate is increasing or decreasing or to be constant by detecting the change in the input current value to the light source 13 in the initial stage of the control. It is. Therefore, as the change amount ΔI of the input current value, a value that can detect such a significant change in the sap flow rate may be appropriately selected. In step 47, the sap flow sensor 7 measures the sap flow rate in a state after the input current to the light source 13 is changed. In step 48, i = i + 1 is set. In step 49, the input current value set in step 46 (here, I0 + ΔI) is substituted for a variable I (i). In step 50, the sap flow rate measured in step 47 is substituted for the variable a (i) and stored. In step 51, the control device 8 sets k4 = {a (i) -a (i-1)} / {I (i) -I (i-1)} as a photosynthetic coefficient k4 for evaluating the photosynthesis of the plant 2. calculate. Here, k4 corresponds to the first ratio. In step 52, the control device 8 determines the magnitude relationship between k4 and 0 calculated in step 51. In step 52, illuminance control is determined based on whether k4 is positive, negative, or zero. Here, if the determination in step 52 is k4> 0, the process proceeds to step 53, where a control signal is transmitted from the control device 8 to the light source 13, and the input current to the light source 13 is increased by I1 to increase the light intensity. increase. If the determination in step 52 is k4 = 0, the process proceeds to step 54, where a control signal from the control device 8 to the light source 13 is transmitted, and the input current to the light source 13 is not changed. If the determination in step 52 is k4 <0, the process proceeds to step 55, where a control signal is transmitted from the control device 8, and the input current to the light source 13 is reduced by I2 to reduce the light intensity. After step 53, 54, or 55, the process returns to step 47, and the processing from step 47 to step 53, 54, or 55 is repeated. The increase amount I1 of the input current to the light source 13 when k4> 0 in step 53 and the decrease amount I2 of the input current to the light source 13 when k4 <0 in step 55 are set as I1 = I2. Or I1 ≠ I2. Further, the values of I1 and I2 may be changed in the control process in accordance with the magnitude of the absolute value of k4. For example, the values of I1 and I2 may be reduced as the absolute value of k4 decreases.
The above-described control of the input current to the light source 13 can appropriately set an end condition so as to end when k4 satisfies a predetermined condition or the like. In addition, the start condition can be appropriately set to start when predetermined timing information such as progress of the growth stage of the plant 2 or deterioration of the light source 13 is acquired.

  In addition to the cultivation system 41 according to the fourth embodiment, the cultivation system 21 according to the second embodiment further includes an illuminance sensor 10 according to the magnitude relationship between the photosynthetic coefficient k2 = Δa / Δb and 0. Thus, the input current of the light source 13 may be controlled. Further, like the cultivation system 31 according to the third embodiment, the humidity sensor 11 and the temperature sensor 12 are further provided, and the input current of the light source 13 is controlled according to the magnitude relationship between the photosynthetic coefficient k3 = Δc / Δb and 0. You may do so.

  Hereinafter, in order to make it possible to compare the configuration requirements of the present invention with the configurations of the embodiments, the configuration requirements of the present invention are described with reference numerals in the drawings.

<Invention 1>
A water flow measuring means (7) for measuring the flow of water in the body of the plant (2);
The illuminance of light emitted from the light sources (4, 13) to the plant (2) is controlled based on the flow rate of water in the body of the plant (2) measured by the water flow measuring means (7). Illuminance control means (5 and 8, 8);
A cultivation system (1, 21, 31, 41) comprising:
<Invention 2>
In the cultivation system (1, 41) for cultivating the plant (2), the amount of operation input to the illuminance control means for controlling the illuminance of light emitted from the light source (4, 13) to the plant (2) is controlled. A method for controlling the illuminance,
Obtaining a change amount of the operation amount (S4, S9);
Obtaining a change amount of the flow rate of water in the body of the plant when the illuminance is changed (S5, S10, S45, S50);
(S11, S51) obtaining a first ratio (k1, k4) that is a ratio of a change amount of the water content in the body of the plant to a change amount of the operation amount;
Controlling the illuminance based on the first ratio (k1, k4) (S12 to S15, S52 to S55);
Illuminance control method in a cultivation system including
<Invention 3>
In a cultivation system (21) for cultivating a plant (2), a light source (4) is used to cultivate the plant (2).
A method of controlling the illuminance of light emitted to,
Measuring the illuminance (S22);
Obtaining a flow rate of water in the body of the plant (S21);
Obtaining a second ratio (k2) that is a ratio of a change in the flow rate of water in the body of the plant to a change in the illuminance (S23);
Controlling the illuminance based on the second ratio (S24 to S27);
Illuminance control method in a cultivation system including
<Invention 4>
In a cultivation system for cultivating a plant (2), a method for controlling illuminance of light emitted from a light source (4) to the plant (2),
The third ratio (c) is a ratio of the flow rate of water in the body of the plant (2) to the saturation of air around the plant (2),
Obtaining a fourth ratio (k3) that is a ratio of a change in the third ratio (c) to a change in the illuminance (S34);
Controlling the illuminance based on the fourth ratio (S35 to S38);
Illuminance control method in a cultivation system including

1: Cultivation system 2: Plant 3: House 4: Sun 5: Shading curtain 6: Diffusion film 7: Sap flow sensor 8: Control device

Claims (17)

A water flow measuring means for measuring the flow of water in the body of the plant,
An illuminance control unit that controls the illuminance of light emitted from the light source to the plant, based on the flow rate of water in the body of the plant, measured by the moisture flow measurement unit,
A cultivation system comprising: Regarding the illuminance control means for controlling the illuminance by controlling the input operation amount, the ratio of the change in the flow rate of water in the body of the plant measured by the water flow rate measurement means to the change in the operation amount. The first ratio,
The cultivation system according to claim 1, wherein the illuminance is controlled based on the first ratio. The illuminance control means,
The cultivation system according to claim 2, wherein whether to increase, maintain, or decrease the illuminance is determined based on whether the first ratio is positive, negative, or zero. . An illuminance measurement unit that measures the illuminance,
The illuminance control means,
For the change in the illuminance measured by the illuminance measuring means, the ratio of the change in the flow rate of water in the body of the plant measured by the water flow rate measuring means as a second ratio,
The cultivation system according to claim 1, wherein the illuminance is controlled based on the second ratio. The illuminance control means,
The cultivation system according to claim 4, wherein whether to increase, maintain, or decrease the illuminance is determined based on whether the second ratio is positive, negative, or zero. . With a saturation acquisition means for acquiring the saturation of the air around the plant,
The illuminance control means,
The third ratio is a ratio of the flow rate of water in the body of the plant measured by the water flow rate measuring means to the saturation obtained by the saturation obtaining means,
A ratio of a change in the third ratio to a change in the illuminance measured by the illuminance measuring unit is a fourth ratio,
The cultivation system according to claim 4, wherein the illuminance is controlled based on the fourth ratio. The illuminance control means,
The cultivation system according to claim 6, wherein whether to increase, maintain, or decrease the illuminance is determined based on whether the fourth ratio is positive, negative, or zero. .   The cultivation system according to any one of claims 1 to 7, wherein the water flow rate measuring means is a sap flow rate measuring means for measuring a flow rate of sap flowing in a vessel of the plant. The illuminance control means,
A light blocking member that blocks an optical path of light incident on the plant from the light source,
Opening degree control means for controlling an opening ratio of the optical path by the light shielding member,
The cultivation system according to any one of claims 1 to 8, wherein the illuminance is controlled by controlling the open ratio. The illuminance control means,
The cultivation system according to any one of claims 1 to 8, wherein the illuminance is controlled by controlling an input to the light source. A method for controlling the illuminance of light emitted to the plant from a light source in a cultivation system for growing a plant,
When changing the illuminance, the step of acquiring the amount of change in the flow rate of water in the body of the plant,
Controlling the illuminance based on the amount of change;
Illuminance control method in a cultivation system including A method for controlling the illuminance by controlling an operation amount input to illuminance control means for controlling the illuminance of light emitted from the light source to the plant in a cultivation system for growing a plant,
Obtaining a change amount of the operation amount;
When the manipulated variable is changed, a step of acquiring a change in the flow rate of water in the body of the plant,
Acquiring a first ratio which is a ratio of a change amount of a water amount in the body of the plant to a change amount of the operation amount;
Controlling the illuminance based on the first ratio;
Illuminance control method in a cultivation system including Controlling the illuminance based on the first ratio,
Determining whether the first ratio is positive, negative or zero;
Determining whether to increase, maintain, or decrease the illuminance based on whether the first ratio is positive, negative, or zero;
The illuminance control method in the cultivation system according to claim 12, comprising: A method for controlling the illuminance of light emitted to the plant from a light source in a cultivation system for growing a plant,
Measuring the illuminance;
Obtaining a flow rate of water in the body of the plant,
Acquiring a second ratio that is a ratio of a change in a flow rate of water in the body of the plant to a change in the illuminance;
Controlling the illuminance based on the second ratio;
Illuminance control method in a cultivation system including Controlling the illuminance based on the second ratio,
Determining whether the second ratio is positive, negative or zero;
Determining whether to increase, maintain, or decrease the illuminance based on whether the second ratio is positive, negative, or zero;
The illuminance control method in the cultivation system according to claim 14, comprising: A method for controlling the illuminance of light emitted to the plant from a light source in a cultivation system for growing a plant,
The third ratio is a ratio of the flow rate of water in the body of the plant to the saturation of the air around the plant,
Obtaining a fourth ratio that is a ratio of a change in the third ratio to a change in the illuminance;
Controlling the illuminance based on the fourth ratio;
Illuminance control method in a cultivation system including Controlling the illuminance based on the fourth ratio,
Determining whether the fourth ratio is positive, negative or zero;
Determining whether to increase, maintain, or decrease the illuminance based on whether the fourth ratio is positive, negative, or zero;
The illuminance control method in the cultivation system according to claim 16, comprising:

Images