JP6506444B2 - Carbon dioxide application system, carbon dioxide control device, carbon dioxide application method and program - Google Patents

Description

The present invention relates to carbon dioxide (CO ₂ ) application technology in a greenhouse for growing crops.

  Techniques for applying carbon dioxide in a greenhouse for growing crops are known. In order to prevent the outflow of carbon dioxide to the outside of the greenhouse when the ventilation window of the greenhouse is open, Patent Document 1 provides a carbon dioxide concentration sensor outside the greenhouse, and carbon dioxide in the greenhouse when the ventilation window is open It discloses a technique to control the carbon concentration to be equal to the concentration of carbon dioxide in the atmosphere (see abstract).

  Japan also has producers (farmers) who have introduced carbon dioxide application systems in their greenhouses. However, temperature control is most important in Japan, especially in production sites. Therefore, as a result of priority given to temperature control, the application method of applying carbon dioxide in the time before the temperature in the greenhouse rises and ventilation starts (2 to 3 hours in the early morning time zone where solar radiation is still small) is It was widely spread.

JP, 2005-65602, A

In the technology described in Patent Document 1, a total of two carbon dioxide concentration sensors need to be provided inside and outside of the greenhouse, resulting in a problem of high cost.
On the other hand, the present invention provides a technology for performing carbon dioxide application more efficiently at lower cost.

  The present invention comprises: a first storage means for storing a first set value of carbon dioxide concentration; and a second storage means for storing a second set value having a concentration lower than the first set value and 400 ppm or more. When the signal indicating the open / close state of the window in the greenhouse having the window to open / close indicates that the window is closed, the first set value is the concentration set value, and the signal is open in the window And a control means for controlling a carbon dioxide supply means for supplying carbon dioxide to the greenhouse with the second set value as a concentration set value when it is indicated.

  The second set value may be 400 ppm or more and 500 ppm or less.

  The first set value may be 600 ppm or more and 1,500 ppm or less.

  The first set value may be 600 ppm or more and 1000 ppm or less.

  This carbon dioxide application control device has clocking means for measuring time, and the control means is configured to generate carbon dioxide from the carbon dioxide supply means when the time measured by the clocking means is not within a predetermined range. It is not necessary to supply carbon.

  Further, according to the present invention, a carbon dioxide supply unit that supplies carbon dioxide to a greenhouse having a window that opens and closes according to a set temperature, a first storage unit that stores a first set value of carbon dioxide concentration, and the first setting Output from a second storage unit that stores a second set value that is lower than the concentration and is 400 ppm or more, and a detection unit that detects the open / close state of the window in a greenhouse having a window that opens / closes according to the set temperature If the signal indicates that the window is closed, the first set value is the concentration set value, and if the signal indicates that the window is open, the second set value And a control means for controlling a carbon dioxide supply means for supplying carbon dioxide to the greenhouse as the concentration setting value.

  Furthermore, the present invention is a method for applying carbon dioxide in a greenhouse having a window that opens and closes according to a set temperature and a carbon dioxide application system having carbon dioxide supply means for supplying carbon dioxide to the greenhouse, the window opening and closing A step of detecting a state, a step of controlling the carbon dioxide supply means using a first set value as a concentration set value when it is detected that the window is closed, and a step of opening the window And d) controlling the carbon dioxide supply means with a second set value having a concentration lower than the first set value and being 400 ppm or more as a concentration set value when detected. Do.

  At least one of the first set value and the second set value may be determined based on a Faker photosynthesis model.

  The set temperature may be determined based on a Faker photosynthesis model.

  Further, according to the present invention, in the computer having control means and storage means, the storage means stores a first set value of carbon dioxide concentration, and the storage means has a concentration lower than the first set value. And storing the second set value which is 400 ppm or more, the control means detects the open / close state of the window in the greenhouse having the window opened / closed according to the set temperature, the window is closed When it is detected, the control means controls the carbon dioxide supply means using the first set value as the concentration set value, and when it is detected that the window is opened, Controlling the carbon dioxide supply unit by using a second set value having a concentration lower than the first set value and 400 ppm or more as a set concentration value. To provide because of the program.

  According to the present invention, more efficient carbon dioxide application can be performed at lower cost.

The figure which shows the function structure of the carbon-dioxide application system 1000 which concerns on one Embodiment. The figure which shows the hardware constitutions of the carbon dioxide application apparatus 2. FIG. 6 is a flowchart showing the operation of the carbon dioxide control device 250. The figure which shows the relationship between a switching state and a carbon dioxide concentration, and a control signal. The figure which illustrates the simulation conditions of the light synthetic speed concerning one example. The figure which illustrates the simulation conditions of the light synthetic speed concerning one example. The figure which illustrates the simulation result of the photosynthesis speed which concerns on one Example. The figure which illustrates the coefficient used for parameter calculation of the light synthetic model. It shows the temperature dependence of the photosynthesis optimum temperature. The photograph of the crop grown in the application area and the control area is shown. It shows the carbon dioxide concentration dependence of photosynthetic rate.

1. Configuration FIG. 1 is a diagram showing a functional configuration of a carbon dioxide application system 1000 according to an embodiment. The carbon dioxide application system 1000 has a greenhouse 1 and a carbon dioxide application device 2. Carbon dioxide application is carried out for the purpose of promoting the photosynthesis of plants grown in the greenhouse 1 (specifically, promoting the Rubisco's carboxylation reaction). The greenhouse 1 is a greenhouse for growing crops, and has an openable window 11, a temperature sensor 12, and an open / close detection means 13. The temperature sensor 12 is a sensor that measures the temperature in the greenhouse 1 (hereinafter referred to as “room temperature”). The window 11 is a window that opens and closes automatically according to the room temperature and the set temperature. When the window 11 is open, the ventilation of the air in the greenhouse 1 and the outside air is promoted. When the window 11 is closed, ventilation is suppressed. The window 11 opens when the room temperature becomes higher than the set temperature, and closes when the room temperature becomes lower than the set temperature. The open / close detection means 13 detects the open / close state (open or closed) of the window 11 and outputs a signal (hereinafter referred to as “open / close state signal”) indicating the detected result. As the open / close detection means 13, any one such as a magnetic sensor type or a mechanical type may be used.

  The carbon dioxide application device 2 is a device for applying carbon dioxide in the greenhouse 1. The carbon dioxide application device 2 includes a carbon dioxide supply unit 21, a storage unit 22, a concentration measurement unit 23, a control unit 24 and a clock unit 25. The carbon dioxide supply means 21 supplies carbon dioxide into the greenhouse 1. The storage means 22 stores parameters relating to the concentration setting value of carbon dioxide when applying carbon dioxide. In this example, the storage unit 22 sets parameters relating to two different density setting values (hereinafter referred to as “first setting value” and “second setting value”. The second setting value is lower than the first setting value). Remember. In this example, the parameters related to the concentration setting value include information for specifying the upper limit value and the lower limit value of the carbon dioxide concentration. The concentration measuring means 23 measures the carbon dioxide concentration in the greenhouse 1. The control unit 24 controls the carbon dioxide supply unit 21 based on the parameters stored in the storage unit 22 and the carbon dioxide concentration measured by the concentration measurement unit 23. In this example, when the open / close state signal indicates that the window 11 is closed, the control means 24 sets the first set value as the density set value. On the other hand, when the open / close state signal indicates that the window 11 is open, the second set value is set as the density set value. The clock means 25 measures the current time.

  FIG. 2 is a diagram showing a hardware configuration of the carbon dioxide application device 2. The carbon dioxide application device 2 includes a carbon dioxide generation device 200, a carbon dioxide concentration sensor 230, a carbon dioxide control device 250, a fan 260, and a duct 270. The carbon dioxide generator 200 is a kerosene combustion type carbon dioxide generator. The carbon dioxide generator 200 performs ignition (on) and fire suppression (off) in accordance with an external control signal. The carbon dioxide concentration sensor 230 measures the concentration of carbon dioxide, and outputs a signal (hereinafter referred to as a carbon dioxide concentration signal) indicating the measurement result. The carbon dioxide concentration sensor 230 is installed near the crop P to be grown in the greenhouse 1.

The carbon dioxide control device 250 is a device that controls the carbon dioxide generation device 200, and has, for example, a program relay. The program relay has a processor, a memory, and a timer. In this example, the carbon dioxide control device 250 outputs a signal for controlling the carbon dioxide generator 200 based on the open / close state signal and the carbon dioxide concentration signal. The memory of the carbon dioxide control device 250 stores two concentration set values of a first set value and a second set value and a concentration range as parameters related to the concentration set value. The carbon dioxide control device 250 uses the first set value when the open / close state signal indicates that the window 11 is closed, and when the open / close state signal indicates that the window 11 is open. Use the second set value. When the carbon dioxide concentration indicated by the carbon dioxide concentration signal exceeds the upper limit value, the carbon dioxide control device 250 outputs a signal for turning off the carbon dioxide generating device 200, and the carbon dioxide concentration falls below the lower limit value. When it is turned on, a signal for turning on the carbon dioxide generator 200 is output. In addition, the program relay can output a signal for turning on the carbon dioxide generator 200 only in a specific time zone using a timer. In this case, the memory of the carbon dioxide control device 250 stores parameters (application start time and application end time) specifying the application time zone.

  The carbon dioxide controller 250 has a user interface (e.g., a display and a keypad) for entering or changing parameters related to concentration settings. The user can input or change parameters related to concentration settings via this interface.

  The fan 260 and the duct 270 are mechanisms for delivering the carbon dioxide generated by the carbon dioxide generator 200 in the vicinity of the crop to be grown. In this example, the fan 260 is interlocked with the carbon dioxide generator 200, and the fan rotates only when the carbon dioxide generator 200 is generating carbon dioxide.

  The carbon dioxide generator 200 is an example of the carbon dioxide supply unit 21. The carbon dioxide concentration sensor 230 is an example of the concentration measurement unit 23. The carbon dioxide control device 250 is an example of the storage unit 22, the control unit 24, and the timing unit 25.

2. Operation FIG. 3 is a flowchart showing the operation of the carbon dioxide control device 250. The flow of FIG. 3 is started, for example, when the carbon dioxide control device 250 is powered on. In step S100, the carbon dioxide control device 250 determines whether the current time is within a predetermined application time zone. If it is determined that the current time is within the application time zone (step S100: YES), the carbon dioxide control device 250 shifts the process to step S101. If it is determined that the current time does not fall within the application time zone (step S100: NO), the carbon dioxide controller 250 outputs a signal to turn off the carbon dioxide generator 200 (step S106).

  In step S101, the carbon dioxide control device 250 acquires the open / close state. The open / close state is indicated by the open / close state signal. In step S102, the carbon dioxide control device 250 determines whether the window 11 is closed. If it is determined that the window 11 is closed (step S102: YES), the carbon dioxide control device 250 determines to use the first set value as the concentration set value (step S103). When it is determined that the window 11 is open (step S102: NO), the carbon dioxide control device 250 determines to use the second set value as the concentration set value (step S104).

  In step S105, the carbon dioxide control device 250 determines whether the carbon dioxide concentration Ph indicated by the carbon dioxide concentration signal exceeds the upper limit value of the concentration. If it is determined that the carbon dioxide concentration Ph exceeds the upper limit value of the concentration (step S105: YES), the carbon dioxide control device 250 outputs a signal to turn off the carbon dioxide generator 200 (step S106). If it is determined that the carbon dioxide concentration Ph does not exceed the upper limit value of the concentration (step S105: NO), the carbon dioxide control device 250 shifts the process to step S107.

In step S107, the carbon dioxide control device 250 determines whether the carbon dioxide concentration Ph indicated by the carbon dioxide concentration signal is lower than the lower limit value of the concentration. If it is determined that the carbon dioxide concentration Ph is below the lower limit value of the concentration (step S107: YES), the carbon dioxide control device 250 outputs a signal to turn on the carbon dioxide generator 200 (step S108). When it is determined that the carbon dioxide concentration Ph does not fall below the lower limit value of the concentration (step S107: NO), the carbon dioxide control device 250 determines that the carbon dioxide generation device 20
The state of 0 is maintained (step S109). That is, when the signal to turn on the carbon dioxide generating device 200 is output until then, the carbon dioxide control device 250 outputs a signal to turn on the carbon dioxide generating device 200 continuously, and until then, the carbon dioxide generating device 200 is turned off. If a signal to cause the carbon dioxide generator 200 is output, a signal to turn off the carbon dioxide generator 200 is continuously output. The flow of FIG. 3 is repeatedly executed at a predetermined timing (for example, periodically).

  FIG. 4 is a diagram showing the relationship between the open / close state signal and the carbon dioxide concentration signal, and the control signal output from the carbon dioxide control device 250. In this example, the density set value is used as the upper limit value of the density, and a value obtained by subtracting the density width ΔP from the density set value as the lower limit value is used. When the open / close state signal indicates that the window 11 is closed, and the carbon dioxide concentration Ph indicated by the carbon dioxide concentration signal satisfies Ph> Pth1, the carbon dioxide control device 250 A control signal to turn off the generator 200 is output. Pth1 indicates a first set value. When the open / close state signal indicates that the window 11 is closed, and the carbon dioxide concentration Ph satisfies Ph <(Pth1-ΔP), the carbon dioxide control device 250 generates the carbon dioxide generator 200. Output a control signal to turn on the In the case where the open / close state signal indicates that the window 11 is open, the carbon dioxide control device 250 detects carbon dioxide when the carbon dioxide concentration Ph indicated by the carbon dioxide concentration signal satisfies Ph> Pth 2. A control signal to turn off the generator 200 is output. Pth2 indicates a second set value. If the carbon dioxide concentration Ph satisfies Ph <(Pth2-ΔP) when the open / close state signal indicates that the window 11 is open, the carbon dioxide control device 250 generates the carbon dioxide generator 200. Output a control signal to turn on the The density range for the first set value and the density range for the second set value may be different from each other.

3. Example 3-1. Simulation Next, an application example of the present invention will be described. First, the estimation result of the light synthesis speed by simulation will be described. 5 and 6 are diagrams showing the conditions of the simulation. FIG. 7 is a diagram illustrating a simulation result of light synthesis speed in one embodiment. The simulation was performed under the following conditions. In addition, the following comparative example is corresponded to the application method (henceforth "the conventional application") currently widely adopted by the producer which is applying carbon dioxide. In this example, since the temperature in the greenhouse rises from about 9 am and the window may open, the timer control is applied only for 2 hours from 6 am.
Photosynthesis model: Improved Farker (Farquhar) model Crop: Eustoma grandiflorum (Raf.) Shinn)
Temperature inside the greenhouse: based on the observed value on January 13, 2012 in a certain coniferous greenhouse grown greenhouse (Figure 5)
Solar radiation: same as above (Fig. 5)
Greenhouse carbon dioxide concentration: same as above (Figure 6)
Window opening and closing temperature: 25 ° C
(Example)
Pth1: 1000 ppm
Pth2: 400 ppm
Application time zone: 8 am to 4 pm (comparative example)
Carbon dioxide application is performed only for 2 hours from 6 am The carbon dioxide concentration at the time of application is 1000 ppm

It supplements about the photosynthesis model used by the present Example. The photosynthetic model used here is the photosynthetic model proposed by Farker et al. (Farquhar GD, von Caemmerer S, Berry JA. 1980. A biochemical model of photosynthesis CO ₂ assimilation in leaves of C3 species. Planta 149: 78-90) (Sharkey TD 1985 Photosynthesis in inmtact leaves of C3 plants, Phisics, phsiology and rate limitations. Botanical Review 51: 53-105). Hereinafter, this improved model of the Farker is simply referred to as a Farker model.

In the Farker model, the light synthesis rate A is expressed by the following equation (1).
Here, Av is a photosynthetic rate when the Rubisco carboxylation reaction is rate-limited, and is represented by the following formula (2).
Aj is a photosynthetic rate in the case of electron transfer limited, and is expressed by the following equation (3).
Ap is the photosynthetic rate under the phosphoric acid rate limiting, and is expressed by the following formula (4).
Also, R is respiration.

  Regarding the meaning and calculation method of each parameter in the equations (2) to (4), the paper of Kim et al. (Kim SH, Lieth JH. 2003. A coupled model of photosynthesis, stomatal conductance and transmission for a rose leaf (Rosa hybrida L) .).)It is described in. For some parameters, other documents such as De Puri et al. (De Pury DGG, Farquuhar GD, 1997. Simple scaling of photosynthesis from leaves to canopies without the errors of big-leaf models. Plant, Cell and Environment 20: 537-557) was used.

The present inventor studied the temperature dependence of the photosynthetic characteristics of Eustoma grandiflorum and rose, and from the measured values of photosynthetic rate under various temperature conditions, the maximum rate Vcmax of Rubsco carboxylation reaction, the maximum rate of electron transfer Jmax, the respiration rate The temperature dependence of Rd, the constant (-1 / k / RH) for converting atmospheric carbon dioxide concentration to in-leaf carbon dioxide concentration, and phosphoric acid utilization rate Pu was clarified. In this example, Ci = (1-1 / k / RH) Ca was used as a conversion equation of atmospheric carbon dioxide partial pressure Ca and in-leaf carbon dioxide partial pressure Ci. The inventor of the present invention approximates the temperature dependence of these parameters with a polynomial of up to fourth order, and clearly shows that the photosynthetic rate calculated using the parameters calculated with these polynomials agrees well with the measured values. did. As an example, FIG. 8 shows values of coefficients indicating the temperature dependence of these parameters in Eustoma grandiflorum. In this example, polynomial approximation is used for Vcmax, Jmax, Rd, and −1 / k / RH, and exponential approximation is used for Pu. Coefficient ai
Represents the coefficient of the i-th term.

  The parameters of the Farker model are not limited to this. The Farker model may be combined with another model. Also, the temperature dependence of the parameters is not limited to the one using the polynomial described above. A so-called Arrhenius equation or an improved Arrhenius equation may be used. Also, for crops whose parameters are not known in the Farker model, values of crops whose parameters are known may be substituted.

  Refer again to FIG. As a result of simulation, in the example, the integrated photosynthesis amount per day was increased by 16% as compared with the comparative example. Thus, according to the examples, it can be seen that carbon dioxide application is performed more effectively as compared with the conventional application method.

The conventional application widely used at production sites was to apply carbon dioxide only in the early morning (for example, from 6 am to 8 am), and not to apply carbon dioxide in other time zones. Such application methods are described in several documents. For example, Takashi Ohsuka, 2003, carbon dioxide control, p. 170-177, Japan Institutional Horticultural Association ed., 5th edition Institutional Horticultural Handbook, Japan Institutional Horticultural Association, Japan, in the cultivation of cucumber, ventilated from 30 minutes after sunrise. It is described that carbon dioxide application is carried out for 2 to 3 hours before starting. In addition, Agriculture and Mountain Fishing Village Cultural Association ed., Agricultural technology system 卉 3, Environmental elements and their control, Control of carbon dioxide, p. 536, in cultivation of carnation, 30 minutes to 2 hours before sunrise, CO 2 application It is stated to do. In addition, Noyama Fishing Village Cultural Association ed., Agro-technics ed., Gakuen ed. 3, Environmental factors and their control, control of carbon dioxide, p. 527, in the sun area, stop the application of carbon dioxide in the daytime on a fine day, The application of carbon dioxide application on cloudy days is described. Furthermore, Noyama and Fishing Village Cultural Association, ed., Agricultural technology system 卉 3, Environmental factors and their control, control of carbon dioxide, p. 523 is a suitable place for carbon dioxide application as the difference of carbon dioxide application effect depending on the area. It is described that although there are many sunny areas, it is suitable for plant horticulture but not suitable for carbon dioxide application. However, according to the present invention, carbon dioxide application is possible even in a sunny area. In addition, although it is described in FIG. 3 of the page of this reference that Shizuoka with much sunshine is unsuitable for carbon dioxide application, as mentioned later, the present invention is also effective in cultivation in Shizuoka.

  On the other hand, the inventor of the present invention considered a method for performing carbon dioxide application under strong light, with the idea that carbon dioxide application exerts its effect under strong light rather than under weak light. First of all, carbon dioxide application is also performed when the ventilation window is open. However, because it is useless to make carbon dioxide too high concentration when the ventilation window is open, it is a two-stage process of high concentration when the ventilation window is closed and low concentration when the ventilation window is open. Apply carbon. Second, the temperature at which the ventilation window is opened is set higher than in the past in order to prolong the time for applying carbon dioxide at high concentration as much as possible. The photosynthetic rate is dependent on temperature, and there is a temperature at which the photosynthetic rate is maximum (photosynthetic optimum temperature). The optimum temperature for photosynthesis is known to shift to the high temperature side as the carbon dioxide concentration increases under strong light conditions (see, for example, FIG. 9). That is, under high carbon dioxide concentration conditions, the temperature at which the ventilation window opens can be set higher than before from the viewpoint of photosynthesis. On the other hand, if the temperature at which the ventilation window is opened is too high, the quality of the crop may be affected, and the temperature at which the ventilation window opens is determined in consideration of these circumstances as a whole.

  In the example of FIG. 7, the window opening / closing temperature is 25 ° C. in each of the embodiment and the comparative example, but according to the above concept, the window opening / closing temperature of the embodiment can be set higher. In that case, since the photosynthesis rate is expected to further increase, it is expected that the difference between the photosynthesis amount of the example and the comparative example is further improved than the 16% increase described in FIG. Thus, according to the present invention, more effective carbon dioxide application can be performed as compared with the comparative example.

3-2. Demonstration test in the field Next, a demonstration experiment in the field was performed under the following conditions.
(Test conditions)
Farming area: 2 greenhouses in 2 consecutive buildings in Shizuoka Prefecture Size of the agricultural area: about 700 m ² per building
Breed: Turquoise (Pickorosa Snow)
Fixed number of plants: About 1300 Set planting time: Mid-October 2012 Shipping: February-March 2013

Under the above conditions, cultivation was performed with one greenhouse as an application zone (example) and one as a control zone (comparative example). Carbon dioxide application was performed in the application area, and no carbon dioxide application was performed in the control area. The more detailed application conditions are as follows.
(Application zone)
Carbon dioxide application time: 8:00 to 15:00
Carbon dioxide application start: December Ventilation temperature: 30 ° C
Carbon dioxide concentration: 430 ppm (when the window is open) / 800 ppm (when the window is closed)
(Control area)
Carbon dioxide application: None The same conditions as the application area except for the above

  FIG. 10 shows photographs of crops grown in the application zone and the control zone. The right is the crop grown in the application area and the left is the control area. It can be seen that the crops grown in the application area have more florets and that flowering is progressing. Below, more quantitative data are used to explain this point.

Table 1 shows the shipping rates in the application area and the control area. Some of the fixed planted plants do not have enough flowers and do not have sufficient plant height to have the quality that can be shipped to the market. Table 1 shows the percentage of fixed plants that can be shipped. The shipping rate of the control area was 79.6%, while the shipping rate of the application area was 98.9%, which is more than 9 points higher than that of the control area.

Table 2 shows the breakdown of shipped flower grades. The flowers shipped are classified into one of the 3 grades of excellent, excellent and good according to a predetermined standard. Here, among those which were not classified as being excellent as being excellent in flowering number 3 or more and 2 or more, those which were not classified as excellent or excellent in flowering number 2 or more and 1 or more. Flowering number 1) was classified as good. In Table 2, "class" indicates classification based on stem length [cm].

  The excellent rate of the control area was 43%, while the excellent rate of the application area was 69%, which is more than 25 points higher. As described above, it was found that in the application section, not only the shipping rate is high but also the excellent rate is high, and by applying the present invention, high quality products can be shipped at a high rate.

3-3. About the carbon dioxide concentration About the influence of the carbon dioxide concentration at the time of carbon dioxide application, it evaluated by measuring the photosynthetic rate under different carbon dioxide concentration. Measurements were made during the day in the field where the above demonstration test was conducted. It has been used for the measurement (Evenary White). The measurement conditions are as follows.
Carbon dioxide concentration: 350 ppm (control)
380 ppm, 410 ppm, 430 ppm (application zone)
Leaf temperature: about 29 ° C
Light intensity: PPFD 1200 μmolm ^-2 s ^-1
(Red LED light source including 10% blue LED)
Humidity: 60%
For the measurement of the photosynthesis rate, a photosynthesis measurement apparatus LI-6400 manufactured by LI-COR was used. The photosynthetic rate of the control was measured at the same concentration as the concentration of carbon dioxide in the control greenhouse while the ventilation window was opened.

  FIG. 11 shows the carbon dioxide concentration dependence of the photosynthetic rate. In the application area, when the carbon dioxide concentration was 380 ppm (corresponding to the atmospheric carbon dioxide partial pressure), no significant difference was observed with the photosynthesis rate in the control area. This is considered to be one of the factors that the carbon dioxide concentration in the control area is 350 ppm and the difference from the atmospheric carbon dioxide partial pressure is small. On the other hand, when the carbon dioxide concentration was set to 410 ppm or 430 ppm higher than the atmospheric carbon dioxide partial pressure, the photosynthetic rate was greatly improved. Thus, more effective carbon dioxide application can be performed by performing carbon dioxide application at a carbon dioxide concentration higher than the atmospheric carbon dioxide partial pressure.

The carbon dioxide concentration when the window is open may be a concentration higher than the atmospheric level (for example, 400 ppm or more), but may be specifically determined as follows, for example. First, as the temperature condition, it is assumed that the set temperature for opening the ventilation window. As light conditions, strong light (for example, 1000 μmol m ⁻² s ⁻¹ PPFD) is assumed. Under these temperature conditions and light conditions, the carbon dioxide concentration on the low concentration side (second set value) is higher than a predetermined ratio (for example, 5%, 10%, etc.) compared to the case without carbon dioxide application, Carbon dioxide conditions at which the photosynthetic rate is increased are determined using the Farker model. With regard to the carbon dioxide concentration on the high concentration side (first set value), the carbon dioxide concentration (about 1000 ppm as an example) at which the photosynthetic rate saturates under the above-mentioned temperature condition and light condition is determined using the Farker model. As the carbon dioxide concentration at which the photosynthetic rate is saturated, the change rate of the photosynthetic rate has a predetermined threshold value (for example, 10%, 5%, 1%, etc.) in the characteristics (A-Ci curve) of photosynthetic rate-carbon dioxide concentration. Adopt a carbon dioxide concentration below The carbon dioxide concentration may be determined using an actual value of the photosynthetic rate, instead of the prediction of the photosynthetic rate using the Farker model.

  Patent Document 1 eliminates the waste of carbon dioxide application when the ventilation window is opened (see paragraph 0012), specifically, substantially eliminating the outflow of carbon dioxide out of the greenhouse. The purpose is (paragraph 0018). Therefore, as in the present invention, controlling the carbon dioxide concentration higher than the atmospheric level when the window is open contradicts the object of Patent Document 1, and the present invention is conceived based on Document 1 Is difficult. Furthermore, while the technology of Patent Document 1 requires two carbon dioxide concentration sensors in total in the greenhouse and inside and outside, which is expensive, the present invention does not require the carbon dioxide concentration sensor to be installed outdoors, and thus a low cost system. It can be built.

4. Modifications The present invention is not limited to the embodiments described above, and various modifications are possible. Hereinafter, some modified examples will be described. Two or more of the following modifications may be used in combination.

The first set value Pth1 and the second set value Pth2 are not limited to those described in the embodiment. For the first set value Pth1, a carbon dioxide concentration at which a desired photosynthetic rate is obtained may be used by using a photosynthesis model such as a Farker model or by another method. As the first set value Pth1 [ppm], for example, a value in the following range is used.
600 ≦ Pth1 ≦ 1500 (5)
The range of the following expression (6) is more preferable for the first set value Pth1.
600 ≦ Pth1 ≦ 1000 (6)
Further, as the second set value Pth2 [ppm], for example, a value in the following range is used.
400 ≦ Pth2 ≦ 500 (7)
The second set value Pth2 may be a concentration higher than the atmospheric carbon dioxide concentration, even if it is out of the range of the equation (7). Note that at least one of the first set value, the second set value, and the window opening / closing temperature among the parameters relating to carbon dioxide application may be determined using a Farker model.

  The relationship between the threshold for turning carbon dioxide application on or off and the set value of carbon dioxide concentration is not limited to that described in the embodiment. For example, with the set value of the carbon dioxide concentration as the center, the set value plus the concentration range may be set as the upper limit (the threshold for turning off), and the setting value minus the concentration range may be set as the lower limit (the threshold for turning on). Alternatively, the upper limit value and the lower limit value may be set respectively. Moreover, control methods other than those described in the embodiment, for example, PI control or PID control may be used to turn on / off carbon dioxide application.

  The hardware configuration of the carbon dioxide control device 250 is not limited to those exemplified in the embodiment. For example, in place of (or in addition to) the kerosene combustion type illustrated in the embodiment, the carbon dioxide supply means 21 uses a gas cylinder, uses exhaust gas from heating, or uses industrial exhaust gas. It may be adopted. When a gas cylinder or the like other than the kerosene combustion type is used, the carbon dioxide application device 2 may not have the fan 260 and the duct 270. Also, part of the functional configuration described in FIG. 1 may be deleted. For example, the clock means 25 may be omitted. Also, the function as the carbon dioxide supply means 21 and the function as the control means 24 may be provided by a single device.

  Although the example which applied this invention to cultivation of Eustoma grandiflorum was demonstrated in the Example, the crops used as an object of the present invention are not limited to Eustoma grandiflorum. The present invention is applicable to C3 plants in general. In addition, although the photosynthesis model described in the examples is intended for a single leaf, a model in which clumps are considered may be used based on the Farker model.

  Some functions of the carbon dioxide application device 2 (for example, the storage unit 22, the control unit 24, and the timing unit 25) may be implemented as computer software. For example, in the control software in a so-called ubiquitous control system (remote control system using a computer network), the algorithm described in the embodiment may be used.

DESCRIPTION OF SYMBOLS 1 ... Greenhouse, 2 ... Carbon-dioxide application apparatus, 11 ... Window, 12 ... Temperature sensor, 13 ... Opening-and-closing detection means, 21 ... Carbon-dioxide supply means, 22 ... Storage means, 23 ... Concentration measurement means, 24 ... Control means, 25 ... Timekeeping means, 200 ... carbon dioxide generator, 230 ... carbon dioxide concentration sensor, 250 ... carbon dioxide control unit, 260 ... fan, 270 ... duct, 1000 ... carbon dioxide application system

Claims (9)

A carbon dioxide concentration sensor installed near the plants grown in the greenhouse having the opening and closing windows, and
A carbon dioxide generator for generating carbon dioxide to be supplied into the greenhouse;
And a carbon dioxide control device that controls the carbon dioxide generator based on the carbon dioxide concentration measured by the carbon dioxide concentration sensor.
The carbon dioxide control device
First storage means for storing a first set value of carbon dioxide concentration;
A second storage unit configured to store a second set value having a concentration lower than the first set value and 400 ppm or more;
When the window is closed in the greenhouse, the first set value is set as a concentration set value, and when the window is opened, the second set value is set as a concentration set value to set the carbon dioxide generator. And a control means for controlling the carbon dioxide application system. The carbon dioxide application system according to claim 1, further comprising setting value determining means for determining at least one of the first setting value and the second setting value based on a predetermined photosynthesis model and given temperature environment and light conditions. The carbon dioxide application system according to claim 1 or 2, wherein the second set value is 400 ppm or more and 500 ppm or less. The carbon dioxide application system according to any one of claims 1 to 3, wherein the first set value is 600 ppm or more and 1,500 ppm or less. The said 1st preset value is 600 ppm or more and 1000 ppm or less. The carbon dioxide application system according to claim 4 characterized by things. Has clock means to measure time,
5. The carbon dioxide generator according to any one of claims 1 to 4, wherein the control means does not supply carbon dioxide from the carbon dioxide generator if the time measured by the time measuring means is not in a predetermined range. The carbon dioxide application system as described in a term. First storage means for storing a first set value of carbon dioxide concentration;
A second storage unit configured to store a second set value having a concentration lower than the first set value and 400 ppm or more;
When the window is closed in a greenhouse having a window that opens and closes, the first set value is set as a concentration set value, and when the window is opened, the second set value is set as a concentration set value. Control means for controlling a carbon dioxide generator for generating carbon dioxide to be supplied into the greenhouse based on the carbon dioxide concentration measured by a carbon dioxide concentration sensor installed near a plant grown from the window in And a carbon dioxide control unit. A carbon dioxide concentration sensor installed near a plant grown from the window in a greenhouse having a window that opens and closes, a carbon dioxide generator that generates carbon dioxide to be supplied into the greenhouse, and the carbon dioxide concentration sensor And a carbon dioxide application system having a carbon dioxide controller for controlling the carbon dioxide generator based on the measured carbon dioxide concentration.
Storing the first set value of carbon dioxide concentration by the carbon dioxide control device;
Storing the second set value having a concentration lower than the first set value and 400 ppm or more than the carbon dioxide control device;
When the window is closed in the greenhouse, the carbon dioxide control unit sets the first set value as the concentration set value, and when the window is opened, the second set value as the concentration set value. Controlling the carbon dioxide generator. A carbon dioxide concentration sensor installed near a plant grown from the window in a greenhouse having a window that opens and closes, a carbon dioxide generator that generates carbon dioxide to be supplied into the greenhouse, and the carbon dioxide concentration sensor A computer used as a carbon dioxide control device in a carbon dioxide application system having a carbon dioxide control device that controls the carbon dioxide generation device based on a measured carbon dioxide concentration;
Storing the first set value of carbon dioxide concentration by the carbon dioxide control device;
Storing the second set value having a concentration lower than the first set value and 400 ppm or more than the carbon dioxide control device;
When the window is closed in the greenhouse, the carbon dioxide control unit sets the first set value as the concentration set value, and when the window is opened, the second set value as the concentration set value. Controlling the carbon dioxide generator.