Plant cultivation system

Abstract

We provide a plant cultivation system that enables the stable cultivation of fruit and vegetable plants. [Solution] The system comprises a cultivation space that houses multiple cultivation shelves for growing fruit and vegetable plants, a light source that irradiates light onto the fruit and vegetable plants grown on each cultivation shelf, a light detection unit that detects the light intensity to each cultivation shelf, a carbon dioxide detection unit that detects the carbon dioxide concentration of each cultivation shelf, a temperature and humidity detection unit that detects the temperature and humidity of each cultivation shelf, and a control unit that controls at least the light intensity, carbon dioxide concentration, and temperature and humidity. The control unit includes performing evaluation 1, which evaluates the photosynthetic rate at each cultivation shelf by changing the carbon dioxide concentration; evaluation 2, which evaluates the photosynthetic rate at each cultivation shelf by changing the temperature and humidity; and evaluation 3, which evaluates the photosynthetic rate at each cultivation shelf by changing the light intensity. Based on the results of evaluations 1 to 3, it determines cultivation conditions corresponding to a predetermined photosynthetic rate, and cultivates the fruit and vegetable plants under the determined cultivation conditions.

Description

[Technical Field]

[0001] This disclosure relates to a plant cultivation system. [Background technology]

[0002] In recent years, there has been a growing demand for vegetable production in plant factories using artificial light. While production techniques for some leafy vegetables, such as lettuce, have advanced, there is a need to explore cultivation methods for fruiting vegetables such as tomatoes.

[0003] For example, Patent Document 1 describes a plant cultivation system comprising a cultivation chamber that forms a closed space inside which is isolated from the outside air, and cultivation containers arranged within the closed space that can be used for cultivating plants, the system further comprising a cultivation environment control unit that forms a cultivation environment necessary for cultivating the plants within the closed space and performs measurements to evaluate the photosynthesis of the plants in the cultivation environment. Patent Document 2 describes a photosynthesis evaluation apparatus characterized by comprising: a test air generating means for mixing raw air and carbon dioxide gas to generate test air with a predetermined carbon dioxide concentration; a test chamber into which the test air obtained by the test air generating means is introduced and which can be sealed to enclose a subject performing photosynthesis; a light source unit for irradiating the subject with light; a carbon dioxide concentration measuring means for measuring the carbon dioxide concentration in the gas at the outlet of the test chamber; and a processing means for calculating the amount of carbon dioxide fixed by the subject from the carbon dioxide concentration of the test air and the carbon dioxide concentration measured by the carbon dioxide concentration measuring means. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2022 / 202561 [Patent Document 2] Japanese Patent Publication No. 2007-71758 [Overview of the project] [Problems that the invention aims to solve]

[0005] In cultivating fruit and vegetable plants using multiple trellises, it is essential to establish stable fruit production by cultivating them under appropriate growing conditions.

[0006] One embodiment of this disclosure aims to solve the problem of providing a plant cultivation system capable of stably cultivating fruit and vegetable plants. [Means for solving the problem]

[0007] This disclosure includes the following aspects: <1> A cultivation space that houses multiple cultivation shelves for growing fruit and vegetable plants, A light source that illuminates the fruit and vegetable plants grown on each cultivation shelf, A light detection unit that detects the light intensity to each cultivation shelf, A carbon dioxide detection unit for detecting the carbon dioxide concentration in each cultivation shelf, A temperature and humidity detection unit that detects the temperature and humidity of each cultivation shelf, It comprises at least a control unit that controls light intensity, carbon dioxide concentration, and temperature and humidity, The control unit is Evaluation 1 involves changing the carbon dioxide concentration to evaluate the photosynthetic rate in each cultivation shelf; Evaluation 2 involves changing the temperature and humidity to evaluate the photosynthetic rate in each cultivation shelf; and Evaluation 3 involves changing the light intensity to evaluate the photosynthetic rate in each cultivation shelf. Based on the results of evaluations 1 to 3, determine the cultivation conditions corresponding to a predetermined photosynthetic rate, A plant cultivation system that includes cultivating fruit and vegetable plants under predetermined cultivation conditions. <2> It further includes a light-reflecting member that reflects light emitted from a light source into the interior of the cultivation shelf. <1> The plant cultivation system described above. <3> It further includes an opening and closing mechanism that switches the cultivation space between a sealed state and a ventilated state. <1> or <2> The plant cultivation system described above. <4> During the cultivation period of the fruit and vegetable plant, at least during the period when evaluations 1 to 3 are performed, the cultivation space is in a sealed state, the plant cultivation system according to <3>. <5> During the cultivation period of the fruit and vegetable plant, during the period when evaluations 1 to 3 are performed, the cultivation space is in a sealed state, and during the period when no evaluation is performed, the cultivation space is in a ventilated state, the plant cultivation system according to <3>.

Advantages of the Invention

[0008] According to an embodiment of the present disclosure, a plant cultivation system capable of stably cultivating fruit and vegetable plants is provided.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an embodiment of the plant cultivation system according to the present disclosure.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps, etc.) are not essential unless specifically specified. The same applies to numerical values and their ranges, which do not limit the present disclosure. In the numerical range indicated by "~" in the present disclosure, the numerical values described before and after "~" are included as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another stepwise numerical range. Also, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. In the present disclosure, the term "step" includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step is achieved. In the present disclosure, the "fruit and vegetable plant" means a plant whose harvest is fruits.

[0011] [Plant cultivation system] The plant cultivation system according to the present disclosure includes a cultivation space in which a plurality of cultivation shelves for cultivating fruit and vegetable plants are accommodated, a light source that irradiates light to the fruit and vegetable plants cultivated on each cultivation shelf, a light detection unit that detects the light intensity of each cultivation shelf, a carbon dioxide detection unit that detects the carbon dioxide concentration of each cultivation shelf, a temperature and humidity detection unit that detects the temperature and humidity of each cultivation shelf, and at least a control unit that controls the light intensity, carbon dioxide concentration, and temperature and humidity. The control unit performs an evaluation 1 for evaluating the photosynthesis rate in each cultivation shelf by changing the carbon dioxide concentration, an evaluation 2 for evaluating the photosynthesis rate in each cultivation shelf by changing the temperature and humidity, and an evaluation 3 for evaluating the photosynthesis rate in each cultivation shelf by changing the light intensity, and determines cultivation conditions corresponding to a predetermined photosynthesis rate based on the results of evaluations 1 to 3, and includes cultivating fruit and vegetable plants under the determined cultivation conditions.

[0012] According to the plant cultivation system of the present disclosure, by determining cultivation conditions corresponding to a predetermined photosynthesis rate based on the results of evaluations 1 to 3 and cultivating fruit and vegetable plants under the determined cultivation conditions, the fruit and vegetable plants can be stably cultivated.

[0013] In the plant cultivation system described in Patent Document 1 and the device described in Patent Document 2, it is not possible to evaluate the photosynthesis rate in each cultivation shelf.

[0014] Hereinafter, an embodiment of the plant cultivation system according to the present disclosure will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view showing an embodiment of the plant cultivation system according to the present disclosure.

[0015] The plant cultivation system 100 shown in Figure 1 comprises a cultivation space P that houses a plurality of cultivation shelves 11 for cultivating fruit and vegetable plants, a cultivation room 80 equipped with a light source 21 that irradiates light onto the fruit and vegetable plants cultivated on each cultivation shelf 11, a light detection unit 31 that detects the light intensity to the cultivation shelves 11, a carbon dioxide detection unit 41 that detects the carbon dioxide concentration in the cultivation shelves 11, and a temperature and humidity detection unit 51 that detects the temperature and humidity of the cultivation shelves 11, and a control unit 91.

[0016] <Cultivation space P> As shown in Figure 1, the cultivation space P is formed inside the cultivation room 80. The cultivation room 80 is equipped with an entrance / exit 81 through which people can enter and exit, a ventilation means 83 for exhausting air from inside the cultivation room 80 through an exhaust port 82, and an air intake port 84 for taking in outside air. Furthermore, a carbon dioxide supply unit 85 is connected to the cultivation chamber 80.

[0017] The entrance / exit 81 is preferably formed to be large enough for a person to enter and exit, and has a sealing mechanism to keep the cultivation space P sealed. In the cultivation of fruit and vegetable plants, the cultivation period is longer compared to the cultivation of leafy vegetables, and the presence of an entrance / exit 81 allows for regular human management and harvesting.

[0018] The ventilation means 83 is a means for exhausting the air inside the cultivation room 80 through the exhaust port 82. The exhaust port 82 is an opening for exhausting air. An example of a ventilation means 83 is a fan. The exhaust port 82 preferably has a sealing mechanism to ensure that the cultivation space P is sealed.

[0019] The operation of the ventilation means 83 is controlled by the control unit 91.

[0020] The air intake vent 84 is an opening for taking in outside air. The air intake port 84 preferably has a sealing mechanism so that the cultivation space P can be sealed.

[0021] If the exhaust port 82 and the air intake port 84 have a sealing mechanism, the switching to the sealed state is controlled by the control unit 91.

[0022] The plant cultivation system 100 preferably includes an opening and closing mechanism to switch the cultivation space P between a sealed state and a ventilated state. Specifically, a sealed state can be achieved by closing the inlet / outlet 81 and closing the exhaust port 82 and the air intake port 84. A ventilated state can be achieved by closing the inlet / outlet 81 and opening the exhaust port 82 and the air intake port 84.

[0023] The carbon dioxide supply unit 85 is a means of supplying carbon dioxide to the cultivation room 80. The carbon dioxide supply unit 85 is connected to a carbon dioxide tank (not shown) via a carbon dioxide supply pipe 86. The supply of carbon dioxide from the carbon dioxide supply unit 85 is performed, for example, by opening and closing a valve. A flow meter may be provided in the carbon dioxide supply pipe 86. The opening and closing operation of the valve and the flow rate of carbon dioxide are controlled by the control unit 91.

[0024] <Cultivation shelf> As shown in Figure 1, the cultivation space P has multiple cultivation shelves 11 for growing fruit and vegetable plants. In Figure 1, the cultivation shelves 11 are arranged in three tiers vertically, but the number of tiers is not particularly limited. From the viewpoint of productivity, it is preferable that the number of tiers of cultivation shelves be two or more. From the viewpoint of workability, it is preferable that the number of tiers of cultivation shelves be eight or less.

[0025] In Figure 1, two cultivation containers are placed on one cultivation shelf 11. The number of cultivation containers placed on one cultivation shelf is not particularly limited and can be adjusted as appropriate according to the bottom area of ​​the cultivation shelf.

[0026] In Figure 1, two sets of cultivation shelves, each consisting of three shelves, are shown. However, the number of cultivation shelf sets is not particularly limited and can be adjusted as appropriate according to the volume of the cultivation space P.

[0027] The form of cultivation is not particularly limited, but cultivation using hydroponics, i.e., hydroponic cultivation, is preferred. The form of hydroponic cultivation is not particularly limited and includes conventionally known hydroponic methods such as flood hydroponics, thin-film hydroponics, drip hydroponics, spray hydroponics, and Ebb&Flow cultivation.

[0028] Fruit and vegetable plants are cultivated on the trellises. Fruiting plants are not particularly limited and include solanaceous plants such as tomatoes, eggplants, and bell peppers; cucurbitaceous plants such as melons, cucumbers, pumpkins, and zucchini; legumes such as green beans, peas, and broad beans; roseaceous plants such as strawberries; mallowaceous plants such as okra; and grasses such as corn.

[0029] In particular, the cultivation method described herein is suitable for cultivating plants of the Solanaceae family or Cucurbitaceae family. The fruit vegetables cultivated in the hydroponic cultivation apparatus described herein are preferably plants of the Solanaceae family or Cucurbitaceae family, more preferably tomatoes or melons, and even more preferably tomatoes.

[0030] Tomatoes include varieties such as midi tomatoes, cherry tomatoes, and fruit tomatoes. Melons, on the other hand, include varieties such as green-fleshed and red-fleshed netted melons and non-netted melons.

[0031] <Light source> As shown in Figure 1, the plant cultivation system 100 includes a light source 21 that irradiates light onto the cultivation shelves 11. The light source is not particularly limited and examples include semiconductor light sources such as LEDs (light-emitting diodes) and discharge lamps such as fluorescent lamps. From the viewpoint of suppressing heat generation from the light source, it is preferable that the light source be an LED.

[0032] There may be one type of LED, or there may be two or more types. LEDs may emit visible light such as red, blue, or green, or they may emit ultraviolet light (wavelength 380 nm or less) or infrared light (wavelength 780 nm or more). In particular, from the viewpoint of promoting photosynthesis in fruit and vegetable plants, LEDs that emit light in the wavelength range of 400 nm to 700 nm are preferred. Furthermore, increasing the fruit yield per plant is important in terms of improving energy efficiency and space utilization efficiency, and from this viewpoint, the combined use of red and blue LEDs is more preferable.

[0033] The light source is positioned on the side of the fruit and vegetable plant. By irradiating the fruit and vegetable plant with artificial light from the side, the size (especially the height) of the plant can be controlled. The light source may be placed not only on the side of the fruit and vegetable plant, but also vertically above it. In Figure 1, multiple light sources are placed at equal intervals along the side of the fruit and vegetable plants, parallel to the direction of gravity.

[0034] As shown in Figure 1, it is preferable that a light-reflecting member 22 is provided at a position opposite the light source 21 with the fruit and vegetable plants in between, to reflect the light emitted from the light source into the inside of the cultivation shelf 11.

[0035] The light-reflecting member is not particularly limited as long as it is a member that has the function of reflecting light. Examples of light-reflecting members include reflectors and reflective sheets. A light-reflecting member may also be a member having a light-reflecting layer provided on the surface of a support.

[0036] Examples of reflectors include metal plates (such as aluminum plates) and resin plates (white resin plates). Examples of reflective sheets include sheets having a metal vapor-deposited film formed by vapor-depositing a metal (such as aluminum) as a light-reflecting layer onto a resin sheet (such as polypropylene, polyethylene, or polyethylene terephthalate), sheets having a metal foil (such as aluminum foil) laminated onto the resin sheet as a light-reflecting layer, and sheets having a coating film formed by applying a light-reflective paint to the resin sheet as a light-reflecting layer.

[0037] The light-reflecting member 22 prevents light emitted from the light source 21 from leaking out of each cultivation shelf, and also suppresses the diffusion of carbon dioxide from each cultivation shelf to other cultivation shelves.

[0038] <Photodetector> As shown in Figure 1, the plant cultivation system 100 includes a light detection unit 31 that detects the light intensity on the cultivation shelf 11.

[0039] The light detection unit 31 is preferably positioned so that its light-receiving surface faces the light source 21. For example, a quantum light sensor (e.g., "LI-190R" manufactured by LI-COR Corporation) can be used as the light detection unit 31. If the light sources are arranged in two or more directions on the fruit and vegetable plant, the light-receiving surface of the light detection unit is positioned facing each light source, and the sum of the measured light intensities is taken as the light intensity.

[0040] Light intensity can be controlled by changing the type and number of light sources 21, changing the distance between the light sources 21 and the fruit and vegetable plants, or by using a dimmable light source.

[0041] <Carbon dioxide detection unit> As shown in Figure 1, the plant cultivation system 100 includes a carbon dioxide detection unit 41 that detects the carbon dioxide concentration in the cultivation shelf 11.

[0042] It is preferable that the carbon dioxide detection unit 41 be positioned in a location where it is less affected by the cultivation space other than the target cultivation shelf and where the risk of water damage from nutrient solution is low. From the above viewpoint, it is preferable that the carbon dioxide detection unit 41 be placed in the upper center of each cultivation shelf. As the carbon dioxide detection unit 41, for example, a carbon dioxide concentration meter (for example, "LI-850" manufactured by LI-COR Corporation) can be used.

[0043] The carbon dioxide concentration can be controlled, for example, by supplying carbon dioxide from the carbon dioxide supply unit 85 or by using the ventilation means 83.

[0044] <Temperature and humidity detection unit> As shown in Figure 1, the plant cultivation system 100 includes a temperature and humidity detection unit 51 that detects the temperature and humidity of the cultivation shelf 11.

[0045] It is preferable that the temperature and humidity detection unit 51 be positioned in a location where it is less affected by the cultivation space other than the target cultivation shelf and where the risk of water wetting from nutrient solution is low. From the above viewpoint, it is preferable that the temperature and humidity detection unit 51 be placed in the upper center of each cultivation shelf. For the temperature and humidity detection unit 51, for example, a temperature and humidity sensor (for example, "THA-3151" manufactured by T&D Corporation) can be used.

[0046] Temperature and humidity can be controlled, for example, by air conditioning equipment installed in the cultivation room.

[0047] <Department Head> The control unit 91 is connected to each light intensity detection unit 31, each carbon dioxide detection unit 41, and each temperature and humidity detection unit 51. The control unit 91 receives data from each light intensity detection unit 31, each carbon dioxide detection unit 41, and each temperature and humidity detection unit 51, and performs evaluation 1, evaluation 2, and evaluation 2 based on the received data. The control unit 91 also determines cultivation conditions corresponding to a predetermined photosynthetic rate based on the results of evaluations 1 to 3. Furthermore, the control unit 91 controls the light intensity, carbon dioxide concentration, and temperature and humidity of the cultivation room in order to cultivate fruit and vegetable plants under the determined cultivation conditions.

[0048] The control unit 91 controls at least the light intensity, carbon dioxide concentration, and temperature and humidity. The control unit 91 can evaluate the rate of photosynthesis by changing the light intensity, carbon dioxide concentration, and temperature and humidity. The control unit 91, for example, handles 100 μmol / m³ 2 / s~800μmol / m 2 The light intensity is varied within the range of / s. The control unit 91 changes the carbon dioxide concentration, for example, within a range of 300 ppm to 2000 ppm. The control unit 91 changes the temperature, for example, within a range of 20°C to 29°C. The control unit 91 changes the relative humidity, for example, within a range of 50% to 80%. The control unit 91, for example, when the vapor pressure deficit is 3 g / m³, will be controlled. 3 ~10g / m 3 The temperature and relative humidity are controlled to achieve this.

[0049] -evaluation- The control unit 91 performs evaluation 1, which evaluates the photosynthetic rate in each cultivation shelf by changing the carbon dioxide concentration; evaluation 2, which evaluates the photosynthetic rate in each cultivation shelf by changing the temperature and humidity; and evaluation 3, which evaluates the photosynthetic rate in each cultivation shelf by changing the light intensity.

[0050] For example, based on the set evaluation conditions, the control unit 91 controls the light intensity, carbon dioxide concentration, and temperature and humidity conditions. The carbon dioxide detection unit 41 detects the carbon dioxide concentration and transmits the obtained data to the control unit 91. The control unit 91 uses the acquired data to evaluate the photosynthetic rate.

[0051] When performing an evaluation for the first time, the control unit 91 arbitrarily sets the temperature, relative humidity, light intensity, and carbon dioxide concentration, and first evaluates the photosynthetic rate under the arbitrarily set conditions. If the evaluation is being repeated, the photosynthetic rate should first be evaluated under the conditions set in the most recent evaluation. The initial conditions that are set first are referred to as "initial conditions."

[0052] An example of Evaluation 1 is shown. In Evaluation 1, the evaluation is performed with temperature, relative humidity, and light intensity kept constant. Temperature, relative humidity, and light intensity are the same as the initial conditions.

[0053] First, the carbon dioxide concentration in the cultivation shelf is set to the initial conditions, and the carbon dioxide concentration is detected for a predetermined time (for example, 2 hours). Furthermore, the carbon dioxide concentration is set to condition A1, which is lower than the initial condition, and the carbon dioxide concentration is detected in the same manner as described above. Furthermore, the carbon dioxide concentration is set to condition A2, which is higher than the initial condition, and the carbon dioxide concentration is detected in the same manner as described above. Under each condition, the rate of photosynthesis is calculated based on the rate of decrease in carbon dioxide concentration over a predetermined period of time.

[0054] An example of Evaluation 2 is shown. In Evaluation 2, the evaluation is conducted with light intensity and carbon dioxide concentration kept constant. Also, in Evaluation 2, the vapor pressure deficit, calculated using temperature and relative humidity, is kept constant. Light intensity and carbon dioxide concentration are the same as the initial conditions.

[0055] First, the temperature and relative humidity are set to condition B1, which is lower than the initial conditions and has the same vapor pressure deficit as the initial conditions. Then, the carbon dioxide concentration is detected in the same manner as described above. Furthermore, the temperature and relative humidity are set to condition B2, which is higher than the initial conditions and has the same vapor pressure deficit as the initial conditions, and the carbon dioxide concentration is detected in the same manner as described above. Under each condition, the rate of photosynthesis is calculated based on the rate of decrease in carbon dioxide concentration over a predetermined period of time.

[0056] An example of Evaluation 3 is shown. In Evaluation 3, the evaluation is performed with temperature, relative humidity, and carbon dioxide concentration kept constant. Temperature, relative humidity, and carbon dioxide concentration are the same as the initial conditions.

[0057] First, the light intensity is set to condition C1, which is weaker than the initial conditions, and the carbon dioxide concentration is detected in the same manner as described above. Furthermore, the light intensity is set to condition C2, which is stronger than the initial conditions, and the carbon dioxide concentration is detected in the same manner as described above. Under each condition, the rate of photosynthesis is calculated based on the rate of decrease in carbon dioxide concentration over a predetermined period of time.

[0058] During the cultivation period of fruit and vegetable plants, it is preferable to keep the cultivation space P sealed for at least the period during which evaluations 1 to 3 are performed. In particular, during the cultivation period of fruit and vegetable plants, it is preferable to keep the cultivation space sealed during the period when evaluations 1 to 3 are performed, and to keep the cultivation space ventilated during the period when no evaluations are performed.

[0059] During the period in which evaluations 1 to 3 are conducted, the cultivation space P is kept sealed to suppress the diffusion of carbon dioxide, allowing for accurate measurement of the carbon dioxide concentration in the cultivation shelves being evaluated. Furthermore, during periods when evaluations are not being conducted, the carbon dioxide concentration when workers enter the cultivation space can be reduced by maintaining ventilation.

[0060] The cultivation period for fruit and vegetable plants refers to the period from the start of planting to harvest. The start of the cultivation period is, for example, the point at which the plant seedlings obtained in the seedling stage are planted in their designated positions in the cultivation container.

[0061] There are no particular limitations on when evaluations 1 to 3 are performed, but it is preferable to perform them when the morphology of the fruit and vegetable plants changes, for example, during the following periods. ·At the time of planting (approximately 20 days after sowing) ·Bud setting period (approx. 30 days after sowing) • Flowering period (approximately 40 days after sowing) • Fruit enlargement begins (approximately 50 days after sowing) • Harvest start time (approximately 80 days after sowing)

[0062] - Determining cultivation conditions - The control unit 91 determines cultivation conditions corresponding to a predetermined photosynthetic rate based on the results of evaluations 1 to 3. The control unit 91 preferably determines the cultivation conditions, including at least light intensity, carbon dioxide concentration, and temperature and humidity.

[0063] Specifically, in Evaluation 1, the carbon dioxide concentration conditions that yielded the fastest photosynthetic rate will be adopted as the cultivation conditions. In Evaluation 2, the temperature and relative humidity conditions that yielded the fastest photosynthetic rate were adopted as the cultivation conditions. In Evaluation 3, the light intensity conditions that yielded the fastest photosynthetic rate were adopted as the cultivation conditions.

[0064] The following describes the specific methods for determining cultivation conditions.

[0065] In Evaluation 1, if sufficient effects are obtained by increasing the carbon dioxide concentration, the high-concentration condition will be adopted. Here, sufficient effects refer to the confirmation of an improvement in the photosynthetic rate of 5% or more relative to the percentage of carbon dioxide concentration increased. In other words, the photosynthetic rate s1 under low carbon dioxide concentration conditions a1 and the photosynthetic rate s2 under high carbon dioxide concentration conditions a2 will be compared, and carbon dioxide concentration a2 will be adopted as the cultivation condition if the following conditions are met. (s2 / s1)-1≧(a2 / a1)×0.05

[0066] Specifically, carbon dioxide concentration a2 is set to twice that of carbon dioxide concentration a1, and carbon dioxide concentration a2 is adopted when the photosynthetic rate becomes 1.1 times or more.

[0067] In Evaluation 2, if sufficient effects are obtained from increasing the temperature, the high-temperature conditions will be adopted. Here, sufficient effects refer to the confirmation of an improvement in the photosynthetic rate of 2% or more relative to the percentage of temperature increase. In other words, the photosynthetic rate t1 under low-temperature conditions (temperature b1) and the photosynthetic rate t2 under high-temperature conditions (temperature b2) will be compared, and if the conditions in the following equation are met, temperature b2 will be adopted as the cultivation condition. (t2 / t1)-1≧(b2 / b1)×0.02

[0068] In Evaluation 3, if sufficient effects are obtained from increasing light intensity, the high-light conditions will be adopted. Here, sufficient effects refer to the confirmation of an improvement in photosynthetic rate of 10% or more relative to the percentage of high light intensity. In other words, the photosynthetic rate u1 under low-light conditions c1 (light intensity c1) and the photosynthetic rate u2 under high-light conditions c2 (light intensity c2) will be compared, and if the conditions in the following equation are met, light intensity c2 will be adopted as the cultivation condition. (u2 / u1)-1≧(c2 / c1)×0.1

[0069] In the plant cultivation system disclosed herein, fruit and vegetable plants are cultivated under predetermined cultivation conditions. This makes it possible to cultivate fruit and vegetable plants stably. [Examples]

[0070] The above embodiments will be described in detail below with reference to examples, but the above embodiments are not limited to these examples.

[0071] <Method for evaluating the rate of photosynthesis> 1) Preparation The plant cultivation system shown in Figure 1 was used. Before evaluation, human management of cultivation was terminated, it was confirmed that no one was inside the cultivation room, and the entrances and exits were closed. To seal the cultivation room, the ventilation system (specifically, the exhaust fan) was stopped, and the sealing mechanisms of the air intake and exhaust vents were activated. The following conditions were set as initial conditions for the cultivation shelves to be evaluated. • Cultivation shelf to be evaluated: Cultivation shelf 1 ·Light intensity: 250μmol / m 2 / s • Carbon dioxide concentration: 1,000 ppm per volume ·Temperature: 27℃ • Relative humidity: 60%RH

[0072] For cultivation shelves 2-6, which are not included in the evaluation, the power to the light source was turned off and the light intensity was set to 0 μmol / m². 2 I used / s.

[0073] 2) Evaluation 1 (Relationship between carbon dioxide concentration and photosynthetic rate) The photosynthetic rate was measured under the initial conditions of a carbon dioxide concentration of 1,000 ppm. Specifically, the initial conditions were set and maintained for 2 hours. After that, carbon dioxide was supplied from the carbon dioxide supply unit, setting the carbon dioxide concentration on cultivation shelf 1 to 1,100 ppm, which is 100 ppm higher than the carbon dioxide concentration to be measured. When the carbon dioxide concentration on cultivation shelf 1 reached 1,100 ppm, the supply of carbon dioxide was stopped. The carbon dioxide concentration on cultivation shelf 1 was measured for approximately 2 hours.

[0074] Next, the carbon dioxide concentration in cultivation shelf 1 was set to condition A1, which is 500 ppm lower than the initial conditions (carbon dioxide concentration of 500 ppm). The carbon dioxide concentration in cultivation shelf 1 was measured for approximately 2 hours.

[0075] Next, the carbon dioxide concentration in cultivation shelf 1 was set to condition A2, which is 500 ppm higher than the initial condition (carbon dioxide concentration of 1,500 ppm). The carbon dioxide concentration in cultivation shelf 1 was measured for approximately 2 hours.

[0076] Under each condition, the rate of photosynthesis was calculated based on the rate of decrease in carbon dioxide concentration.

[0077] 3) Evaluation 2 (Relationship between temperature, humidity, and photosynthetic rate) The temperature was set to 2°C lower than the initial conditions (25°C). The relative humidity was also set to condition B1, which resulted in the same vapor pressure deficit as the initial conditions (55% RH). Condition B1 was maintained for 2 hours. After that, carbon dioxide was supplied from the carbon dioxide supply unit, setting the carbon dioxide concentration on cultivation shelf 1 to 1,100 ppm, which is 100 ppm higher than the carbon dioxide concentration to be measured. When the carbon dioxide concentration on cultivation shelf 1 reached 1,100 ppm, the supply of carbon dioxide was stopped. The carbon dioxide concentration on cultivation shelf 1 was measured for approximately 2 hours.

[0078] Next, the temperature was set to a temperature 2°C higher than the initial condition (temperature 29°C). Also, the relative humidity was set to condition B2 with a relative humidity (relative humidity 65%RH) where the saturation deficit was the same as the initial condition. After setting to condition B2, it was held for 2 hours. Then, carbon dioxide was supplied from the carbon dioxide supply unit, and the carbon dioxide concentration in cultivation shelf 1 was set to 1,100 ppm, which is 100 ppm higher than the carbon dioxide concentration to be measured. When the carbon dioxide concentration in cultivation shelf 1 reached 1,100 ppm, the supply of carbon dioxide was stopped. The carbon dioxide concentration in cultivation shelf 1 was measured for about 2 hours.

[0079] Under each condition, the photosynthesis rate was calculated based on the rate of decrease in carbon dioxide concentration.

[0080] 4) Evaluation 3 (Relationship between light intensity and photosynthesis rate) The light intensity was set to condition C1 with a light intensity 150 μmol / m 2 / s weaker than the initial condition (light intensity 100 μmol / m 2 / s). After setting to condition C1, it was held for 2 hours. Then, carbon dioxide was supplied from the carbon dioxide supply unit, and the carbon dioxide concentration in cultivation shelf 1 was set to 1,100 ppm, which is 100 ppm higher than the carbon dioxide concentration to be measured. When the carbon dioxide concentration in cultivation shelf 1 reached 1,100 ppm, the supply of carbon dioxide was stopped. The carbon dioxide concentration in cultivation shelf 1 was measured for about 2 hours.

[0081] Next, the light intensity was set to condition C2 with a light intensity 150 μmol / m 2 / s stronger than the initial condition (light intensity 400 μmol / m 2 / s). After setting to condition C2, it was held for 2 hours. Then, carbon dioxide was supplied from the carbon dioxide supply unit, and the carbon dioxide concentration in cultivation shelf 1 was set to 1,100 ppm, which is 100 ppm higher than the carbon dioxide concentration to be measured. When the carbon dioxide concentration in cultivation shelf 1 reached 1,100 ppm, the supply of carbon dioxide was stopped. The carbon dioxide concentration in cultivation shelf 1 was measured for about 2 hours.

[0082] Under each condition, the photosynthesis rate was calculated based on the rate of decrease in carbon dioxide concentration.

[0083] 5) Determining cultivation conditions Based on the results of evaluations 1 to 3 above, cultivation conditions were determined to obtain the necessary photosynthetic rate. After the evaluations were completed, cultivation was continued under the determined conditions.

[0084] Evaluation 1 revealed that the photosynthetic rate was 1.20 μmol / s / plant under initial conditions, 1.00 μmol / s / plant under condition A1, and 1.30 μmol / s / plant under condition A2. (1.20 / 1.00)-1=0.20>{(1000 / 500)×0.05} (1.30 / 1.20)-1≈0.08>{(1500 / 1000)×0.05} Therefore, a carbon dioxide concentration of 1500 ppm was adopted as the cultivation condition.

[0085] Evaluation 2 revealed that the photosynthetic rate was 1.20 μmol / s / plant under initial conditions, 1.15 μmol / s / plant under condition B1, and 1.22 μmol / s / plant under condition B2. (1.20 / 1.15)-1≈0.04>{(27 / 25)×0.02} (1.22 / 1.20)-1 ≈ 0.017 < {(29 / 27) × 0.02} Therefore, a temperature of 27°C and a relative humidity of 60%RH were adopted as cultivation conditions.

[0086] Evaluation 3 revealed that the photosynthetic rate was 1.20 μmol / s / plant under initial conditions, 1.00 μmol / s / plant under condition C1, and 1.30 μmol / s / plant under condition C2. (1.20 / 1.00)-1=0.20<{(250 / 100)×0.1} (1.30 / 1.20)-1 ≈ 0.08 < {(400 / 250) × 0.1} Therefore, the light intensity is 100 μmol / m². 2 The / s setting was adopted as a cultivation condition. [Explanation of Symbols]

[0087] 11 Cultivation shelf 21 Light source 22 Light-reflecting member 31 Light detection unit 41 Carbon dioxide detection unit 51 Temperature and humidity detection unit 80 Cultivation room 81 Entrance / Exit 82 Exhaust port 83 Ventilation means 84 Air supply port 85 Carbon Dioxide Supply Department 86 Carbon dioxide supply pipe 91 Control Unit 100 Plant Cultivation Systems P cultivation space

Claims

1. A cultivation space that houses multiple cultivation shelves for growing fruit and vegetable plants, A light source that illuminates the fruit and vegetable plants grown on each cultivation shelf, A light detection unit that detects the light intensity to each cultivation shelf, A carbon dioxide detection unit for detecting the carbon dioxide concentration in each cultivation shelf, A temperature and humidity detection unit that detects the temperature and humidity of each cultivation shelf, It comprises at least a control unit that controls the light intensity, the carbon dioxide concentration, and the temperature and humidity, The control unit, Evaluation 1 involves changing the carbon dioxide concentration to evaluate the photosynthetic rate in each cultivation shelf; Evaluation 2 involves changing the temperature and humidity to evaluate the photosynthetic rate in each cultivation shelf; and Evaluation 3 involves changing the light intensity to evaluate the photosynthetic rate in each cultivation shelf. Based on the results of evaluations 1 to 3, cultivation conditions corresponding to a predetermined photosynthetic rate are determined, A plant cultivation system comprising cultivating the aforementioned fruit and vegetable plants under determined cultivation conditions.

2. The plant cultivation system according to claim 1, further comprising a light-reflecting member that reflects light emitted from the light source into the interior of the cultivation shelf.

3. The plant cultivation system according to claim 1 or claim 2, further comprising an opening and closing mechanism for switching the cultivation space between a sealed state and a ventilated state.

4. The plant cultivation system according to claim 3, wherein the cultivation space is kept sealed for at least the period during which evaluations 1 to 3 are performed during the cultivation period of the fruit and vegetable plants.

5. The plant cultivation system according to claim 3, wherein, during the cultivation period of the fruit and vegetable plants, the cultivation space is kept sealed during the period in which evaluations 1 to 3 are performed, and the cultivation space is kept ventilated during the period in which no evaluations are performed.

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