JP7514510B2 - Method, program and device for calculating environmental response characteristics of plants - Google Patents

Description

The present invention relates to a method, program, and device for calculating environmental response characteristics of plants.

In order to increase the yield of crops such as tomatoes grown in greenhouses and reduce the risk of pests, it is necessary to control the greenhouse environment. There are various environmental conditions in a greenhouse, such as temperature, humidity, _CO2 concentration, light, root zone temperature, and nutrient solution EC, and the number of combinations of environmental conditions that can be set for environmental control is enormous.

JP 2016-195555 A

When controlling the environmental conditions in a greenhouse, it is necessary to determine whether the target greenhouse environment is appropriate, but in order to make precise judgments according to the type and variety of crops being grown in the greenhouse, detailed standards for each type and variety are required.

However, in the past, standards were set broadly based on past experience, making it difficult to make detailed judgments.

The present invention aims to provide a method, program, and device for calculating the environmental response characteristics of plants that can calculate the environmental response characteristics for each item or variety.

The method for calculating the environmental response characteristics of a plant of the present invention is a method for calculating the environmental response characteristics of a plant, in which a computer executes a process of sequentially setting a specific environmental condition to a standard condition and a plurality of investigation conditions in a space in which the growth environment of a plant can be controlled, while keeping environmental conditions other than the specific environmental condition constant, obtaining an index value indicating the growth of the plant cultivated in the space, and calculating, as a relative growth degree indicating the growth degree under the specified investigation conditions, a value indicating the ratio of the change in the index value per unit time at the first time to the average of the change in the index value per unit time at the time set to the standard condition before a first time set to the specified investigation condition and the change in the index value per unit time at the time set to the standard condition after the first time.

The plant environmental response characteristic calculation method, program, and device of the present invention have the effect of being able to calculate the environmental response characteristics of each item or variety.

FIG. 1A is a diagram showing the configuration of an information acquisition system according to an embodiment, and FIG. 1B is a photograph showing the interior of an environmental control chamber 50. As shown in FIG. FIG. 2 is a diagram illustrating a hardware configuration of the control device in FIG. FIG. 2 is a functional block diagram of the control device of FIG. 4 is a flowchart showing the process of the control device. FIG. 5A is a diagram showing an example of an environment control pattern, and FIG. 5B is a graph showing the results of weight measurement and the change in weight at predetermined time intervals. FIG. 6(a) is a table showing the relative growth rate at each temperature, and FIG. 6(b) is a graph in which the data in FIG. 6(a) is expressed as a function. 1 is a graph showing a schematic diagram of changes in temperature in a greenhouse. FIG. 1 is a diagram showing a procedure for estimating crop yield. 9A to 9C are diagrams (part 1) for explaining the first embodiment. FIG. 2 is a second diagram for explaining the first embodiment; 11A to 11C are diagrams (part 1) for explaining the second embodiment. FIG. 11 is a second diagram for explaining the second embodiment; FIG. 13(a) to FIG. 13(c) are diagrams (part 1) for explaining the third embodiment. FIG. 11 is a second diagram for explaining the third embodiment; FIG. 15(a) is a diagram showing an environmental control pattern according to a modified example, and FIG. 15(b) is a graph showing the weight measurement results and the rate of weight increase for each predetermined time period. 13A and 13B are diagrams showing other examples of environmental control patterns in the modified example.

The information acquisition system 100 according to one embodiment will be described in detail below with reference to Figs. 1 to 8. The information acquisition system 100 according to this embodiment is a system that automatically determines and outputs environmental response characteristics for each crop type and variety.

Figure 1(a) shows a schematic configuration of the information acquisition system 100. As shown in Figure 1(a), the information acquisition system 100 includes an environmental control chamber 50, an environmental control device 60, an irrigation device 70, a weighing scale 80, and a control device 10 as an environmental response characteristic calculation device.

The environmental control chamber 50 has an internal space in which crops can be grown. The environment within the internal space of the environmental control chamber 50 can be controlled by an environmental control device 60. Figure 1(b) is a photograph showing the interior of the environmental control chamber 50.

The environmental control device 60 is a device that controls various environmental conditions (air temperature, humidity, _CO2 concentration, light, root zone temperature, nutrient solution EC (electric conductivity)) in the internal space of the environmental control chamber 50. That is, the environmental control device 60 includes a heating and cooling appliance, a humidifier, a dehumidifier, a _CO2 concentration regulator, LED (Light Emitting Diode) lighting, a thermal heater or chiller that controls the root zone temperature, a nutrient solution EC control device, etc. The environmental control device 60 controls the environment in the environmental control chamber 50 under the control of the control device 10.

The irrigation device 70 is a device that waters the crops grown in the internal space of the environmental control chamber 50 under the direction of the control device 10.

The weighing scale 80 measures the weight of the crops being grown in the internal space of the environmental control chamber 50 as an index value showing the growth of the crops. The weighing scale 80 outputs the measurement result to the control device 10.

The control device 10 controls the environmental control device 60 and the irrigation device 70, obtains the measurement results of the weighing scale 80, and creates a graph showing how the growth rate changes in response to changes in environmental conditions (e.g., temperature) for each crop (item/variety). This graph shows the environmental response characteristics of the crop. The control device 10 also displays the created graph on the display unit 93 (see Figure 2) or outputs it to an external device.

2 shows the hardware configuration of the control device 10. As shown in FIG. 2, the control device 10 includes a CPU 90, a ROM 92, a RAM 94, a storage unit (HDD in this case) 96, a network interface 97, a display unit 93, an input unit 95, and a drive for a portable storage medium 99. The display unit 93 includes a liquid crystal display, and the input unit 95 includes a keyboard, a mouse, a touch panel, and the like. These components of the control device 10 are connected to a bus 98. In the control device 10, the CPU 90 executes a program (including a program for calculating environmental response characteristics of a plant) stored in the ROM 92 or the HDD 96, or a program (including a program for calculating environmental response characteristics of a plant) read from the portable storage medium 91 by the drive for a portable storage medium 99. The functions of the components shown in FIG. 3 are realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

Figure 3 shows a functional block diagram of the control device 10. In the control device 10, the CPU 90 executes a program to realize the functions of an environment control unit 12 as a setting unit, an irrigation control unit 14, a weight acquisition unit 16 as an acquisition unit, a relative growth degree calculation unit 18 as a calculation unit, and an output unit 20, as shown in Figure 3.

The environmental control unit 12 controls the environmental control device 60 based on a predetermined environmental control pattern, and controls various environmental conditions in the environmental control chamber 50. Here, in this embodiment, the environmental control unit 12 controls specific environmental conditions (e.g., air temperature) based on the environmental control pattern, while controlling environmental conditions other than the specific environmental conditions (e.g., humidity, _CO2 concentration, light, root zone temperature, nutrient solution EC) to be kept constant.

The irrigation control unit 14 controls the irrigation device 70 to irrigate (water) the crops at predetermined time intervals. The irrigation control unit 14 also controls the irrigation device 70 to irrigate the crops to the extent that the water overflows from the seedling pots just before measuring the weight of the crops using the weighing scale 80.

The weight acquisition unit 16 acquires the weight measurement result from the weighing scale 80. The weight acquisition unit 16 determines the weight of the crop to be the weight obtained by subtracting the total weight of the seedling pot, the soil, and the water in the seedling pot from the measurement result of the weighing scale 80.

The relative growth calculation unit 18 calculates the relative growth of the crop at each temperature from the crop weight measurement results acquired by the weight acquisition unit 16. Here, the relative growth at each temperature means the ratio (%) of the crop weight change at each temperature (survey condition) to the crop weight change at the reference temperature (reference condition).

The output unit 20 converts the relative growth rate calculated by the relative growth rate calculation unit 18 into a function and creates a graph of the environmental response characteristics for each crop (for each type or variety). The output unit 20 also displays the created graph on the display unit 93 or outputs it to an external device.

(Regarding processing of the control device 10)
Next, the processing of the control device 10 will be described in detail with reference to the flowchart of Fig. 4 and other drawings as appropriate. Here, the control device 10 of the present embodiment creates and outputs a graph (a graph showing environmental response characteristics) showing how the growth rate of a certain crop (e.g., item "tomato" and variety "Momotaro") changes with temperature, as an example.

In step S10, the environmental control unit 12 executes environmental control based on a predetermined environmental control pattern. Here, the environmental control pattern is a pattern in which the temperature is changed at predetermined intervals, as shown in FIG. 5(a). In FIG. 5(a), the predetermined time for changing the temperature is shown as a unit time (1 Time). Note that the predetermined time (1 Time) may be one day or another length of time, and may be determined for each variety or type of crop.

Specifically, the environmental control pattern in FIG. 5(a) has a base temperature of 22°C, and has temperatures other than the base temperature sandwiched between them, such as 22°C, 16°C, 22°C, 14°C, 22°C, and so on.

In the case of the environmental control pattern of Fig. 5(a), in step S10 (first time) of Fig. 4, the environmental control unit 12 sets the air temperature in the environmental control chamber 50 to 22°C. It is assumed that the environmental control unit 12 controls other environmental conditions (humidity, _CO2 concentration, light, root zone temperature, nutrient solution EC) to be maintained at predetermined values.

Next, in step S12, the irrigation control unit 14 waits until a predetermined time has elapsed. In this case, the predetermined time is the aforementioned 1 Time. Therefore, when the predetermined time (1 Time) has elapsed, the irrigation control unit 14 proceeds to step S14.

When the process proceeds to step S14, the irrigation control unit 14 performs irrigation. Here, it issues an instruction to the irrigation device 70 to irrigate the base of the crop (seedling pot), and stops irrigation when the water overflows from the seedling pot.

Next, in step S16, the weight acquisition unit 16 acquires the weight measured by the weighing scale 80. The weight acquired by the weight acquisition unit 16 in step S16 includes the weight of the crop, the weight of the seedling pot, the weight of the soil, and the weight of the water used for irrigation in step S14. In this embodiment, before starting the process of FIG. 4, the total weight of the seedling pot, the weight of the soil, and the weight of the water used when the seedling pot is irrigated to the extent that it overflows are measured and stored as a correction weight. The weight acquisition unit 16 then subtracts the correction weight from the weight measured in step S16 to accurately measure the weight of the crop. Note that the irrigation in step S14 is for measuring the weight of the crop as described above, so the irrigation control unit 14 is assumed to appropriately perform irrigation necessary for cultivating the crop separately from the process of FIG. 4.

Next, in step S18, the relative growth calculation unit 18 judges whether or not the environmental control based on the environmental control pattern has been completed. If the judgment in step S18 is negative, the process returns to step S10. When the process returns to step S10, the environmental control unit 12 executes environmental control based on the environmental control pattern in FIG. 5(a). That is, in step S10 (second time) in FIG. 4, the environmental control unit 12 sets the air temperature in the environmental control chamber 50 to 16°C. Thereafter, the processes and judgments in steps S12, S14, S16, and S18 are executed as described above.

Then, the processes and judgments of steps S10 to S18 are repeated, and when the environmental control based on the environmental control pattern of FIG. 5(a) is completed, the judgment of step S18 becomes positive, and the relative growth degree calculation unit 18 proceeds to step S20.

When the process proceeds to step S20, the relative growth calculation unit 18 calculates the relative growth rate for each environmental condition. In this embodiment, the relative growth rate is calculated for each temperature. The method for calculating the relative growth rate for each temperature is described in detail below.

FIG. 5(b) shows a graph of the measurement result of the weight (g/plant) of the crop and the weight change (g/plant) for each predetermined time (1 Time). When the relative growth degree calculation unit 18 determines the relative growth degree (R _x ) at a certain temperature (x° C.), it first specifies the weight change (dW _n ) during the time (time n) during which the temperature was maintained. The relative growth degree calculation unit 18 also determines the weight change (dW n-1 ) during the time (time n-1) immediately before the time n during which the temperature was maintained (x° C.) and the weight change (dW _n+1 ) during the time (time n+ ₁ ) immediately after the time n during which the temperature was maintained (x° C.). The weight changes dW _n-1 and dW _n+1 are weight changes during the time during which the temperature was maintained at a reference temperature (22° C.). The relative growth degree calculation unit 18 then determines the relative growth degree R _x at the temperature x° C. based on the following formula (1).
_Rx = _dWn / (1/2 (dWn _-1 + dWn ₊₁ )) × 100 ... (1)

As can be seen from the above formula (1), the relative growth rate _Rx means the ratio (%) of the weight change ( _dWn ) during the time maintained at temperature x°C to the average of the weight changes dWn _-1 and dWn ₊₁ during the time maintained at temperature 22°C.

For example, in FIG. 5(a), the relative growth rate _R16 at a time (between Time = 1 and Time = 2) when the temperature is set to 16°C can be calculated from the following formula (2) using the weight changes _dW1 , _dW2 , and _dW3 shown in FIG. 5(b).
_R16 = _dW2 / (1/2 ( _dW1 + _dW3 )) × 100 ... (2)

The relative growth rate at other temperatures can be calculated in a similar manner.

Figure 6 (a) is a table showing the relative growth rate at each temperature obtained as described above. Note that in this embodiment, the reference temperature is set to 22°C, so the relative growth rate at a temperature of 22°C is 100(%).

Returning to FIG. 4, in the next step S22, the output unit 20 converts the relative growth rate into a function, creates a graph showing the environmental response characteristics, and outputs it. Specifically, the output unit 20 plots the data in the table of FIG. 6(a) on a graph, and creates a graph as shown in FIG. 6(b) using the least squares method or the like. Note that the horizontal axis of the graph in FIG. 6(b) is temperature, and the vertical axis is relative growth rate. The output unit 20 then displays the generated graph on the display unit 93, or outputs it to an external device.

The entire process of FIG. 4 is thus completed. The environmental response characteristics for environmental conditions other than air temperature (humidity, _CO2 concentration, light, root zone temperature, nutrient solution EC) can also be graphed and output by executing the process of FIG. 4. For example, when the environmental response characteristics for humidity are graphed and output, the humidity is changed based on the same environmental control pattern as FIG. 5(a) (a pattern in which the reference humidity and a humidity other than the reference humidity are alternately repeated) while maintaining the environmental conditions other than humidity constant. Then, the relative growth rate at each humidity can be calculated based on the above formula (1) from the weight change at each humidity.

(Regarding external device processing (part 1))
Here, in the external device, the graph of FIG. 6B output from the control device 10 can be used to perform the following information processing.

For example, the external device may be an information processing device that can be used by workers cultivating crops (item "tomato" and variety "Momotaro") in a greenhouse.

This information processing device acquires environmental information acquired by outdoor sensors installed outside the greenhouse and greenhouse sensors installed inside the greenhouse, greenhouse facility information, equipment information installed in the greenhouse, equipment setting information, and predicted information on the outdoor environment, and estimates the environment inside the greenhouse based on each of the acquired information.

The information processing device also evaluates the estimated environment inside the greenhouse and, based on the evaluation results, outputs control information to the devices to be controlled so as to improve the evaluation results.

When evaluating the environment inside a greenhouse in an information processing device that executes such processing, the graph in FIG. 6(b) can be used. Note that the graph in FIG. 6(b) is prepared for each crop variety and item, so the information processing device uses the graph corresponding to the crops actually grown in the greenhouse (item "tomato" and variety "Momotaro") for the evaluation.

For example, based on the acquired information, the information processing device predicts (1) night room temperature Tn, (2) day room temperature Td, (3) night-day transition average Tm, and (4) day-night transition average Te for the transition of air temperature inside the greenhouse as shown in the schematic diagram of FIG. 7. Here, the information processing device calculates the sunrise and sunset times based on the latitude, longitude, and date information, and calculates the night setting maintenance time mn (minutes) in FIG. 7 based on the calculation results, as well as the night-day transition (morning) time mm (minutes) and the day-night transition (evening) time me (minutes) as functions of solar radiation and outdoor air temperature. The information processing device also determines the time obtained by excluding mn, mm, and me from the time of day as the day setting maintenance time md (minutes).

Then, the information processing device evaluates the predicted greenhouse environment as shown in FIG. 7. Specifically, the information processing device evaluates the predicted greenhouse temperature change by converting it into a score. When converting it into a score, the information processing device refers to the graph (relationship between temperature and relative growth (FIG. 6(b)) obtained from the control device 10. Note that the relative growth on the vertical axis of FIG. 6(b) is hereinafter referred to as the "temperature score", and the value of the relative growth is treated as a score (point). When converting the greenhouse temperature into a score, the information processing device calculates the change in the temperature score at each time. In addition, the information processing device calculates the average of the temperature scores, and sets it as the average temperature score for the day.

Here, the information processing device adjusts (changes) the settings of the device, for example, if the average daily temperature score does not meet a predetermined standard. In this case, the set temperature of the controlled device is adjusted so that the temperature score is higher. For example, if the temperature score for the daytime (or nighttime) time period is low, the set temperature for each time period can be adjusted so that the daytime (or nighttime) temperature score is higher.

The information processing device also uses the daily average temperature score to evaluate the degree of influence of temperature on growth. In this case, the information processing device calculates the predicted growth amount DMo (g/ ^m2 /d) based on the following formula (3), for example, using the daily average temperature score (referred to as S).
DMo = DMp × S ... (3)

Here, DMp is the potential growth amount (g/ ^m2 /d) and means the growth amount in an ideal environment (when there is no inhibition due to temperature and humidity). If DMo does not satisfy the standard, the information processing device changes the set temperature of the controlled device, etc.

The information processing device may display the temperature score trends, the average daily temperature score, the predicted growth volume DMo, etc., and provide them to the worker. This allows the worker to determine whether the environment in the greenhouse is appropriate.

In the above, the information processing device has been described as evaluating the temperature (predicted value) in the greenhouse, but it can also evaluate humidity, _CO2 concentration, light, rhizosphere temperature, and nutrient solution EC in the same manner. In this case, the humidity, _CO2 concentration, light, rhizosphere temperature, and nutrient solution EC (predicted values) in the greenhouse can be evaluated using a graph (similar to FIG. 6(b)) showing the environmental response characteristics for humidity, _CO2 concentration, light, rhizosphere temperature, and nutrient solution EC.

The information processing device can further evaluate the environment based on the measured values (actual values) of environmental information in the greenhouse and output (display) the evaluation results. In this case, the information processing device acquires information detected by the greenhouse sensors (actual air temperature, humidity, _CO2 concentration, light, root zone temperature, nutrient solution EC), and evaluates and displays the greenhouse environment based on a graph showing the environmental response characteristics.

(Regarding external device processing (part 2))
The external device may be an information processing device that estimates the yield of the crop by using a graph of the environmental response characteristics output from the control device 10. This information processing device estimates the yield of the crop based on the photosynthetic characteristics.

In estimating the crop yield, the information processing device performs various calculations using the average temperature, the accumulated solar radiation, and the average _CO2 concentration during the period until harvest, as shown in Fig. 8, to estimate the crop yield. In this calculation, the information processing device can use a graph of the environmental response characteristics output from the control device 10. In Fig. 8, the data shown in the dashed frame is the crop's biological information input by the worker, and the data shown in the gray frame is the environmental information obtained from a sensor or the like. In addition, the data shown in the dashed line frame is information that has been set in advance, and the data shown in the solid line frame is information obtained by calculation.

For example, the information processing device takes into account the environmental response characteristics for temperature when calculating the number of expanded leaves using the average temperature. Also, the information processing device takes into account the environmental response characteristics for light when calculating the integrated amount of received light in a day using the integrated amount of solar radiation. Furthermore, the information processing device takes into account the environmental response characteristics for _CO2 concentration when calculating _the light use efficiency using the average CO2 concentration.

In this way, it becomes possible to estimate the yield with high accuracy. In this embodiment, the control device 10 creates and outputs to an external device a graph showing the environmental response characteristics as shown in FIG. 6(b), but this is not limited to the above. For example, the control device 10 may output to an external device data on the relative growth rate at each temperature as shown in FIG. 6(a). In this case, the external device can create the graph of FIG. 6(b) from the data in FIG. 6(a) and use it in the above-mentioned processing.

As described above in detail, according to this embodiment, the environmental control unit 12 sets the specific environmental condition (e.g., air temperature) in the environmental control chamber 50 to a reference condition (22°C) and a plurality of survey conditions (16°C, 14°C, etc.) in sequence, while keeping the environmental conditions (humidity, _CO2 concentration, light, root zone temperature, nutrient solution EC) other than the specific environmental condition (e.g., air temperature) constant via the environmental control device 60 (S10). In addition, the weight acquisition unit 16 acquires the measured value of the weight of the crop cultivated in the environmental control chamber 50 (S16). Then, the relative growth ratio calculation unit 18 calculates the relative growth ratio Rx of the crop based on the weight change ( _dWn ) of the crop at the time set to the survey condition (e.g., 16°C) and the weight changes (dWn _-1 , dWn ₊₁ ) of the crop at the plurality of times set to the reference condition (22° _C ), thereby calculating the relative growth ratio under each survey condition (S20). This makes it possible to automatically calculate the relative growth ratio under each survey condition for each variety or item.

The output unit 20 also creates and outputs a graph showing the environmental response characteristics for air temperature based on the calculation results of the relative growth degree calculation unit 18 (S22). As a result, in this embodiment, a graph showing the environmental response characteristics as shown in FIG. 6(b) can be automatically created and output. In this case, the graph showing the environmental response characteristics can be output to an external device (information processing device) that evaluates the growth environment of the crops and an external device (information processing device) that estimates the yield of the crops, so that the environment in the greenhouse can be appropriately evaluated and the yield can be appropriately estimated. In addition, since a graph showing the environmental response characteristics can be prepared for each variety and item, the evaluation of whether the environment is appropriate and the estimation of the yield can be performed in a detailed manner according to the type and variety of the crop.

In this embodiment, the relative growth index ( _Rx ) is defined as the ratio ( _{%) of the weight change in the time set under the standard conditions (air temperature 22°C) to the average of the weight change in the time immediately before (dWn-1} ) and the weight change in the time immediately after (dWn ₊₁ ). This makes it possible to calculate an appropriate value for the relative growth index through simple calculations.

In the above embodiment, the environmental control pattern may be a pattern in which two or more temperatures are set between the reference temperature (22°C), such as "22°C", 16°C, 14°C, 20°C, and "22°C". In this case, the weighted average of the weight change (weighted average with the time difference as the weight) may be used as the denominator of the above formula (1) (average of the weight change when the reference temperature is set). For example, when calculating the relative growth rate _R16 at 16°C, the value obtained by multiplying the weight change (dWn _-1 ) at the time immediately before the reference temperature (22°C) by 3 and the value obtained by multiplying the weight change (dWn _-1 ) at the time after the reference temperature (22°C) by 1, the sum of the result and the weighted average divided by 4 may be used as the denominator of the above formula (1). Furthermore, when calculating the relative growth rate _R20 at 20° C., the weight change (dW _{n-1 ) at the time set at the previous reference temperature (22° C.) multiplied by 1 and the weight change (dW n-1 )} at the time set at the next reference temperature (22° C.) multiplied by 3 may be added together, and the resultant sum may be divided by 4 (weighted average), and used as the denominator in the above formula (1). On the other hand, when calculating the relative growth rate _R14 at 14° C., the average of the weight changes at the preceding and following reference temperatures (22° C.) may be used as the denominator in the above formula (1).

In the above embodiment, the reference temperature was set to 22°C and the relative growth rate at 22°C was set to 100%, resulting in a graph showing the environmental response characteristics as shown in Figure 6(b). However, depending on the crop, there may be cases where the relative growth rate exceeds 100% at a certain temperature. In such cases, the temperature at which the relative growth rate was greatest can be used as the reference temperature, and the relative growth rate for each temperature can be recalculated.

In the above embodiment, the relative growth degree calculation unit 18 calculates the relative growth degree Rx of the crop based on the weight change ( _dWn ) of the crop at a time set under the survey conditions (e.g., 16°C) and the weight changes (dWn _-1 , dWn ₊₁ ) of the crop at multiple times set under the reference conditions (22°C), but this is not limited to the above. For example, the relative growth degree _Rx of the crop may be calculated from the following formula (1)' using only one value of the weight change ( _dWz ) of the crop at a _time set under the reference conditions that is closest to the time when the survey conditions were set.
R _x =(dW _n /dW _z )×100 (1)′

Below, we will explain Examples 1 to 3. Note that the present invention is not limited to the following Examples.

Example 1
9(a) to 9(c) and 10 show examples of calculations of environmental response characteristics for air temperature for a crop (item "Tomato", variety "Momotaro York"). FIG. 9(a) shows a temperature treatment pattern when the investigation condition is 35°C and the reference condition is 25°C. In this Example 1, the reference condition (25°C), investigation condition (35°C), and reference condition (25°C) are set in this order, and other environmental conditions (humidity, _CO2 concentration, light, root zone temperature, nutrient solution EC) are set to predetermined values (relative humidity: 50%, _CO2 concentration: 400 ppm, photosynthetically active photon density: 700 μmol·m ^-2 ·s ^-1 , nutrient solution EC: 1.0 dS·s ^-1 ).

As a result, the weight changes of the crops are as shown in Fig. 9(b).The weight changes dW _opt1 and dW _opt2 during the period set under the reference condition (25°C) can be calculated as follows.
dW _opt1 = ln(141.5) - ln(136.4) / (3 - 0) = 0.0122
dW _opt2 = ln(158.6) - ln(150.9) / (9 - 5) = 0.0124
The weight change _dW2 during the period set under the investigation conditions (35°C) is as follows:
_dW2 = ln(147.8) - ln(143.2) / (15 - 11)
= 0.0079
These are shown in Fig. 9(c) Note that the unit of the weight change in Fig. 9(c) is not limited to (g/gh), and may be (/h).

Therefore, from the above formula (1), the relative growth rate (R ₃₅ ) at an air temperature of 35° C. with respect to a reference temperature of 25° C. can be calculated as follows:
_R35 = _dW2 / (1/2 ( _dWopt1 + _dWopt2 )) × 100
= 0.0079 / (1 / 2 (0.0122 + 0.0124)) x 100
= 64.1 (%)

The relative growth rate was calculated in the same manner for other test conditions, and the graph shown in Figure 10 was obtained. In Figure 10, the relative growth rate under the standard conditions (25°C) is 100%.

Example 2
11(a) to 11(c) and 12 show examples of calculations of the environmental response characteristics of a crop (item "Tomato", variety "Momotaro York") with respect to CO2 concentration. FIG. 11(a) shows a set pattern of _CO2 concentration when the investigation conditions are 300 ppm and 1200 ppm, and the reference condition is 400 _ppm . In this Example 2, the reference condition (400 ppm), investigation condition (300 ppm), and investigation condition (1200 ppm) are set in this order, and other environmental conditions (air temperature, humidity, light, root zone temperature, nutrient solution EC) are set to predetermined values (air temperature: 25°C, relative humidity: 50%, photosynthetically active photon density: 700 μmol m ^-2 s ^-1 , nutrient solution EC: 1.0 dS s ^-1 ).

As a result, the weight changes of the crops are as shown in Figure 11(b). The weight change _dW400 during the period set under the reference conditions (400 ppm), and the weight changes dW300 and _dW1200 during the periods set under the investigation conditions ( ₃₀₀ ppm, 1200 ppm) can be calculated as follows:
_dW400 = ln(230.1) - ln(228.5) / (2 - 1) = 0.0070
_dW300 = ln(230.2) - ln(228)/(4 - 3) = 0.0064
_dW1200 = ln(232.8) - ln(230.1) / (6 - 5) = 0.0078
These are shown in Fig. 11(c). Note that the unit of the weight change in Fig. 11(c) is not limited to (g/gh), and may be (/h).

Therefore, from the above formula (1)', the relative growth rate (R ₃₀₀ ) at a CO ₂ concentration of 300 ppm with respect to the reference condition (400 ppm) can be calculated as follows:
_R300 = _dW300 / _dW400 × 100
= 0.0064/0.0070 x 100
= 91.7 (%)

Similarly, the relative growth rate (R ₁₂₀₀ ) at a CO ₂ concentration of 1200 ppm relative to the reference condition (400 ppm) can be calculated as follows:
_R300 = _dW1200 / _dW400 × 100
= 0.0078/0.0070 x 100
= 121.5 (%)

The relative growth rate was calculated in the same manner for other survey conditions, and the graph shown in Figure 12 was obtained. In Figure 12, the relative growth rate under the standard conditions (400 ppm) is 100%.

Example 3
13(a) to 13(c) and 14 show examples of calculations of environmental response characteristics for the nutrient solution EC of a crop (item "Tomato", variety "Momotaro York"). FIG. 13(a) shows a setting pattern of the nutrient solution EC when the investigation condition is 6 dS/m and the reference condition is 2 dS/m. In this Example 3, the reference condition (2 dS/m), investigation condition (6 dS/m), and reference condition (2 dS/m) are set in this order, and other environmental conditions (air temperature, humidity, _CO2 concentration, light, root zone temperature) are set to predetermined values (air temperature: 25°C, relative humidity: 50%, _CO2 concentration: 400 ppm, photosynthetically active photon density: 700 μmol m ^-2 -s ^-1 ).

As a result, the weight changes of the crops are as shown in Figure 13(b). The weight changes dW _EC2-1 and dW _EC2-2 during the period set under the standard conditions (2 dS/m) and the weight change dW _EC6 during the period set under the investigation conditions (6 dS/m) can be calculated as follows:
dW _EC2-1 = ln(149.5) - ln(144.4) / (3 - 0) = 0.0116
_dWEC2-2 = ln(163.6) - ln(157.9) / (15 - 11)
= 0.0089
In addition, the weight change dW _EC6 during the period set under the investigation conditions (6 dS/m) is as follows.
dW _EC6 = ln(154.8) - ln(151.2) / (9 - 5) = 0.0059
These are shown in Fig. 13(c). Note that the unit of the weight change in Fig. 13(c) is not limited to (g/gh), and may be (/h).

Therefore, from the above formula (1), the relative growth rate (R _EC6 ) when the nutrient solution EC = 6 dS/m is compared with the nutrient solution EC = 2 dS/m can be calculated as follows.
R _EC6 = dW _EC6 / (1/2 (dW _EC2-1 + dW _EC2-2 )) × 100
= 0.0059 / (1 / 2 (0.0116 + 0.0089)) x 100
= 57.6 (%)

The relative growth rate was calculated in the same manner for the other test conditions, and the graph shown in Figure 14 was obtained. In Figure 14, the relative growth rate under the standard conditions (nutrient solution EC = 2) is 100%.

(Modification)
In the above embodiment, the relative growth degree at each temperature is calculated from the above formula (1) using the weight change in each time period (1 time period) as shown in FIG. 5(b), but the present invention is not limited to this. For example, the relative growth degree may be calculated using the increase rate of the weight of the crop. Specifically, as shown in FIG. 15(a), the weight of the crop is measured while performing environmental control based on the same environmental control pattern as in FIG. 5(a). Then, the relative growth degree calculation unit 18 calculates the increase rate r n of the weight in each time period (1 time period) from a graph showing the weight measurement result, as shown in FIG. 15(b). Here, the increase rate _{r n can} be calculated by the following formula.
r _n =(lnW _n -lnW _n-1 )/(t _n -t _n-1 ) ...(4)

Here, lnW _n means the natural logarithm of the weight W _n . For example, the rate of increase r ₂ is calculated by dividing lnW ₂ - lnW ₁ by a predetermined time (1 Time).

In addition, r _opt1 to r _opt5 in Fig. 15(b) represent the weight increase rate at the reference temperature (22°C). The increase rates r _opt1 to r _opt5 can also be calculated from the above formula (4). For example, the increase rate r _opt1 is calculated by dividing lnW ₁ - lnW ₀ by a predetermined time (1 Time).

Then, the relative growth calculation unit 18 obtains the relative growth rate (R _x ) of the temperature (x° C.) using the increase rate r _n at the temperature x° C. from the following equation (5).
_Rx = _rn / {( _ropt1 + _ropt2 + ... + _roptM ) / M} x 100 ... (5)

In this modified example, the environmental control pattern does not have to adopt a pattern in which the reference temperature is set to temperatures before and after the temperature other than the reference temperature as in Fig. 15(a). That is, for example, a plurality of temperatures other than the reference temperature may be set between the reference temperatures as shown in Fig. 16. Even in this case, the relative growth rate _Rx can be calculated using the above formula (5).

In the above embodiment and modified example, the weight of the crops is automatically measured using a weighing scale 80 installed in the environmental control chamber 50, but this is not limited to the above. For example, the weight of the crops may be measured by an operator placing the crops on the weighing scale each time. In this case, the measurement results of the weighing scale may be automatically transmitted to the control device 10, or the operator may manually input the measurement results into the control device 10.

In the above embodiment, the weight acquisition unit 16 acquires the weight of the crop measured by the weighing scale 80, but this is not limited to the above. For example, the weight acquisition unit 16 may acquire the weight of the crop estimated from an image of the crop. In this case, the weight of the crop can be estimated based on, for example, the number of pixels included in the area of the captured image in which the crop is captured and a predetermined conversion formula. In this case, watering (step S14) does not need to be performed immediately before acquiring the weight.

In the above embodiment, the weight acquisition unit 16 acquires the weight of the crop from the weighing scale 80 in step S16, and calculates the relative growth rate based on the change in the weight of the crop in step S20. However, this is not limited to the above, and the control device 10 may acquire the surface area or volume of the crop as an index value indicating the growth of the crop in step S16, and calculate the relative growth rate based on the change in the surface area or volume of the crop in step S20. The surface area or volume of the crop can be estimated from an image of the crop. In this case, for example, the surface area or volume of the crop can be estimated based on the number of pixels included in the area of the captured image where the crop is captured and a predetermined conversion formula.

The above processing functions can be realized by a computer. In that case, a program is provided that describes the processing contents of the functions that the processing device should have. The above processing functions are realized on the computer by executing the program on the computer. The program describing the processing contents can be recorded on a computer-readable storage medium (excluding carrier waves, however).

When a program is distributed, it is sold, for example, in the form of a portable storage medium on which the program is recorded, such as a DVD (Digital Versatile Disc) or a CD-ROM (Compact Disc Read Only Memory). The program can also be stored in the storage device of a server computer, and then transferred from the server computer to other computers via a network.

A computer that executes a program stores, for example, a program recorded on a portable storage medium or a program transferred from a server computer in its own storage device. The computer then reads the program from its own storage device and executes processing in accordance with the program. Note that the computer can also read a program directly from a portable storage medium and execute processing in accordance with that program. The computer can also execute processing in accordance with the received program each time a program is transferred from the server computer.

The above-described embodiment is a preferred example of the present invention. However, the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention.

10 Control device (environmental response characteristic calculation device)
12 Environment control unit (setting unit)
16 Weight acquisition unit (acquisition unit)
18 Relative growth rate calculation unit (calculation unit)

Claims (10)

In a space in which the growth environment of a plant can be controlled, while keeping environmental conditions other than a specific environmental condition constant, the specific environmental condition is sequentially set to a reference condition and a plurality of investigation conditions;
acquiring an index value indicative of the growth of the plant cultivated in the space;
calculate, as a relative growth rate indicating the growth rate under the specified investigation conditions, a value indicating a ratio of a change in the index value per unit time during the first time to an average of a change in the index value per unit time during a time set under the reference condition before a first time set under specified investigation conditions and a change in the index value per unit time during a time set under the reference condition after the first time;
A method for calculating environmental response characteristics of a plant, the processing of which is executed by a computer. 2. The method for calculating environmental response characteristics of a plant according to claim 1 , wherein the time set to the standard conditions before the first time is the time immediately before the first time, and the time set to the standard conditions after the first time is the time immediately after the first time. The method for calculating the environmental response characteristics of a plant according to claim 1 or 2, characterized in that the computer further executes a process of calculating and outputting a function indicating a change in the relative growth index in response to a change in the specific environmental condition, based on the relative growth index under a plurality of survey conditions obtained as a result of repeatedly executing the calculation process while changing the specified survey conditions. 4. The method for calculating environmental response characteristics of a plant according to claim 3 , characterized in that, in the output process, the function is graphed and output to an evaluation device that evaluates the growth environment of the plant or an estimation device that estimates a yield of the plant. 5. The method for calculating environmental response characteristics of a plant according to claim 1 , wherein the index value is any one of weight, surface area, and volume of the plant. In a space in which the growth environment of a plant can be controlled, while keeping environmental conditions other than a specific environmental condition constant, the specific environmental condition is sequentially set to a reference condition and a plurality of investigation conditions;
acquiring an index value indicative of the growth of the plant cultivated in the space;
calculate, as a relative growth rate indicating the growth rate under the specified investigation conditions, a value indicating a ratio of a change in the index value per unit time during the first time to an average of a change in the index value per unit time during a time set under the reference condition before a first time set under specified investigation conditions and a change in the index value per unit time during a time set under the reference condition after the first time;
A program for calculating the environmental response characteristics of plants to allow a computer to carry out processing. a setting unit that sequentially sets the specific environmental condition to a reference condition and a plurality of investigation conditions while keeping environmental conditions other than the specific environmental condition constant in a space in which the growth environment of the plant can be controlled;
an acquisition unit that acquires an index value indicating the growth of the plant cultivated in the space;
a calculation unit that calculates, as a relative growth rate indicating a growth rate under the predetermined investigation conditions, a value indicating a ratio of a change in the index value per unit time in a first time period to an average of a change in the index value per unit time in a time period that is set under a reference condition before a first time period that is set under a predetermined investigation condition and a change in the index value per unit time in a time period that is set under the reference condition after the first time period;
A plant environmental response characteristic calculation device comprising: In a space in which the growth environment of a plant can be controlled, while keeping environmental conditions other than a specific environmental condition constant, the specific environmental condition is sequentially set to a reference condition and a plurality of investigation conditions;
acquiring an index value indicative of the growth of the plant cultivated in the space;
a value indicating a ratio of the change in the index value per unit time in the first time to a weighted average of a value obtained by weighting the change in the index value per unit time in a second time set under the reference condition before a first time set under a predetermined investigation condition with a weighting coefficient corresponding to the shortness of the time between the first time and the second time, and a value obtained by weighting the change in the index value per unit time in a third time set under the reference condition after the first time with a weighting coefficient corresponding to the shortness of the time between the first time and the third time, is calculated as a relative growth degree indicating the growth degree under the predetermined investigation condition.
A method for calculating environmental response characteristics of a plant, the processing of which is executed by a computer. a setting unit that sequentially sets the specific environmental condition to a reference condition and a plurality of investigation conditions while keeping environmental conditions other than the specific environmental condition constant in a space in which the growth environment of the plant can be controlled;
an acquisition unit that acquires an index value indicating the growth of the plant cultivated in the space;
a value indicating a ratio of the change in the index value per unit time in the first time to a weighted average of a value obtained by weighting the change in the index value per unit time in a second time set under the reference condition before a first time set under a predetermined investigation condition with a weighting coefficient corresponding to the shortness of the time between the first time and the second time, and a value obtained by weighting the change in the index value per unit time in a third time set under the reference condition after the first time with a weighting coefficient corresponding to the shortness of the time between the first time and the third time, is calculated as a relative growth degree indicating the growth degree under the predetermined investigation condition.
A program for calculating the environmental response characteristics of plants to allow a computer to carry out processing. In a space in which the growth environment of a plant can be controlled, while keeping environmental conditions other than a specific environmental condition constant, the specific environmental condition is sequentially set to a reference condition and a plurality of investigation conditions;
acquiring an index value indicative of the growth of the plant cultivated in the space;
a calculation unit that calculates, as a relative growth degree indicating a growth degree under the specified investigation conditions, a value indicating a ratio of a change in the index value per unit time in a first time to a weighted average of a value obtained by weighting a change in the index value per unit time in a second time set under the reference conditions before a first time set under the specified investigation conditions with a weighting coefficient corresponding to the shortness of the time between the first time and the second time, and a value obtained by weighting a change in the index value per unit time in a third time set under the reference conditions after the first time with a weighting coefficient corresponding to the shortness of the time between the first time and the third time;
A plant environmental response characteristic calculation device comprising:

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