Plant water absorption estimation device

Abstract

To suitably estimate a plant water absorption amount.SOLUTION: A device for estimating the water absorption amount of a plant grown in a plant factory comprises environmental information regarding the growing environment of the plant, the initial weight of the plant at the start of cultivation, and a calculation part 3 that estimates a plant water absorption amount per unit time at a specific point in time based on time information regarding the elapsed time from the time of sowing the plant to the specific point in time. The environmental information comprises saturation difference information regarding the saturation difference of the growing environment, and lighting information regarding the lighting condition of a light, and the calculation part estimates the reference water absorption amount per unit time of the plant at a specific time based on the environmental information, initial weight, and time information, and estimates the water absorption amount based on the reference water absorption amount.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a device for estimating water absorption of a plant. [Background technology]

[0002] In a plant factory, leafy vegetables such as lettuce are generally grown hydroponically in an indoor facility using an artificial light source and a culture solution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-196693 Summary of the Invention [Problem to be solved by the invention]

[0004] The amount of water absorbed by cultivated plants is an indicator of the design of a plant factory and the health of the plants. However, the amount of water absorbed varies depending on the type of plant, the season, and environmental conditions. It would be extremely useful to be able to estimate the amount of water absorbed by plants at a specific time point, taking these changes into account.

[0005] The present disclosure has been made in view of the above circumstances, and its purpose is to provide a water absorption estimation device that can suitably estimate the amount of water absorption of a plant. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, An apparatus for estimating the amount of water absorption of plants grown in a plant factory, a calculation unit that estimates the amount of water absorption per unit time of the plant at a specific time point based on environmental information on the growing environment of the plant, an initial weight of the plant at the start of cultivation, and time information on the elapsed time from the sowing of the plant to the specific time point, the environmental information includes saturation deficit information relating to a saturation deficit of the growing environment and lighting information relating to a lighting state of lighting, The calculation unit estimates a standard water absorption amount per unit time of the plant at the specific time point based on the environmental information, the initial weight, and the time information, and estimates the water absorption amount based on the standard water absorption amount. The present invention provides a device for estimating water absorption of a plant.

[0007] Preferably, the calculation unit estimates an increase in the reference water absorption amount at the specific time point based on the reference water absorption amount and the environmental information, and estimates the water absorption amount based on the increase.

[0008] Preferably, the calculation unit estimates the value of the amount of change that periodically changes relative to the standard water absorption amount at the specific point in time based on the standard water absorption amount, the environmental information, and the time information, and estimates the water absorption amount based on the value of the amount of change at the specific point in time.

[0009] According to another aspect of the present disclosure, A diagnostic device comprising the water absorption amount estimation device, which diagnoses a growth state of a plant based on the water absorption amount estimated by the water absorption amount estimation device, The plant factory includes a culture solution tank that stores a culture solution for hydroponic cultivation of plants, and a water supply device that supplies an equal amount of water to the culture solution tank every time a predetermined amount of the culture solution in the culture solution tank decreases, The diagnostic device performs the following during the current water supply period: The water absorption amount estimating device calculates an integrated water absorption amount by integrating the water absorption amount values ​​estimated from the previous water supply time to the current water supply time; The actual amount of water absorbed by the plant is calculated by subtracting the amount of water evaporated between the previous watering and the current watering period from the amount of water supplied during this watering period. A diagnostic unit is provided which compares the integrated amount of water absorption with the actual amount of water absorption to determine whether the plant is growing normally. The present invention provides a plant growth condition diagnosis device characterized by the above. [Effects of the Invention]

[0010] According to the present disclosure, the amount of water absorption by a plant can be suitably estimated. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating a plant factory and a water absorption estimation device according to an embodiment of the present invention. [Figure 2] 3 is a flowchart showing a method for estimating water absorption according to the present embodiment. [Figure 3] 10 is a graph showing the accuracy of the estimated value. [Figure 4] 10 is a time chart showing the transition of actual values ​​and estimated values ​​over time. [Figure 5] 10 is a time chart showing the transition of actual values ​​and estimated values ​​over time. [Figure 6] 10 is a time chart showing the transition of actual values ​​and estimated values ​​over time. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the present disclosure is not limited to the following embodiments.

[0013] This embodiment relates to a device for estimating the amount of water absorption by plants grown in a plant factory. The plants (crops or agricultural products) grown are, for example, leafy vegetables such as lettuce, and are grown hydroponically in the plant factory. The plant factory is installed in an indoor facility and includes a lighting device that uses an artificial light source such as an LED to irradiate the plants with light, a nutrient solution tank in which the plant roots are immersed, a tank for storing the nutrient solution, an air conditioning system for air conditioning the factory, and a nutrient solution control system for controlling the concentration of components in the nutrient solution. Plants absorb water when their roots absorb the nutrient solution in the nutrient solution tank.

[0014] First, plant seeds are sown in a water-absorbed sponge or the like and germinated there. After germination, the seeds are immersed in a nutrient solution tank together with the sponge or the like. Then, the plants are cultivated or grown in the nutrient solution tank.

[0015] A plant factory and a water absorption estimation device according to this embodiment are schematically shown in Figure 1. The plant factory includes a lighting device 52 that irradiates light onto plants 51, a nutrient solution tank 53 in which the roots of the plants 51 are immersed, a nutrient solution tank 55 that stores nutrient solution 54, a pump 56 that supplies the nutrient solution 54 in the nutrient solution tank 55 to the nutrient solution tank 53, and a return pipe 62 that returns excess nutrient solution 54 from the nutrient solution tank 53 to the nutrient solution tank 55.

[0016] The plant factory also includes a water supply device 57 that supplies the same amount of water into the nutrient solution tank 55 whenever the nutrient solution 54 in the nutrient solution tank 55 decreases by a predetermined amount. The water supply device 57 includes a water supply pipe 58 through which tap water is delivered, a water supply valve 59 that selectively supplies the delivered water into the nutrient solution tank 55, and a flow meter 60 that measures the flow rate of water when the water supply valve 59 is opened. The water supply valve 59 may be a mechanical ball tap valve or a solenoid valve. When the liquid level in the nutrient solution tank 55 decreases by a predetermined amount, the water supply valve 59 automatically opens, and the same amount of water is replenished into the nutrient solution tank 55 from the water supply pipe 58.

[0017] The water absorption estimation device 1 of this embodiment is composed of a personal computer 1A. The water absorption estimation device 1 includes an input unit 2, a calculation unit 3, and an output unit 4. The calculation unit 3 is composed of a personal computer main body 3A. The input unit 2 includes a keyboard 2A, a mouse 2B, and an input port (such as a USB port) of the personal computer main body 3A. The output unit 4 includes a monitor 4A.

[0018] The calculation unit 3 estimates the amount of water absorption per unit time of the plant at a specific point in time based on environmental information about the growth environment of the plant to be cultivated, the initial weight of the plant at the start of cultivation, and time information about the elapsed time from the time the plant was sowed to the specific point in time. Note that estimation is synonymous with calculation. The environmental information includes lighting information about the lighting status of the lighting device 52. The environmental information also includes saturation deficit information about the saturation deficit of the growth environment.

[0019] The input unit 2 is for inputting environmental information, initial weight, and time information. The calculation unit 3 estimates the amount of water absorption based on the environmental information, initial weight, and time information input to the input unit 2.

[0020] The output unit 4 is for outputting the amount of water absorption estimated by the calculation unit 3.

[0021] This embodiment also relates to a method for estimating the amount of water absorption of a plant, which method is executed using a water absorption estimation device 1. As shown in Fig. 2, the water absorption estimation method of this embodiment includes an input step S1 in which the aforementioned environmental information, initial weight, and time information (collectively referred to as input data) are input, a calculation step S2 in which the amount of water absorption per unit time of the plant at a specific point in time is estimated based on the environmental information, initial weight, and time information input in the input step S1, and an output step S3 in which the amount of water absorption estimated in the calculation step S2 is output. The input step S1 is performed using an input unit 2, the calculation step S2 is performed using a calculation unit 3, and the output step S3 is performed using an output unit 4.

[0022] The calculation unit 3 stores the following model formulas (1) to (4) in advance, and estimates the amount of water absorption by the plant in accordance with these model formulas.

[0023]

number

[0024]

number

[0025]

number

[0026]

number

[0027] Regarding equation (1), α t is the final result, the amount of water absorbed by the plant per unit time. The subscript t indicates that the value is at a specific point in time (t).

[0028] μ t is the standard water absorption of a plant per unit time. As plants grow over time after sowing, the amount of water they absorb increases exponentially with time. Standard water absorption refers to the standard or base value of the amount of water absorption that increases over time.

[0029] δ LDt is the reference water absorption amount μ t δ is the amount of increase that increases relative to the growth environment. In particular, it is the amount of increase that increases depending on the growing environment, more specifically, it is the amount of increase that increases when light is irradiated on the plant. When light is irradiated, plants sense that it is daytime and carry out activities such as photosynthesis. Therefore, when light is irradiated, the amount of water absorbed increases compared to when light is not irradiated. This increased amount of water absorption is δ LDt is.

[0030] δ circadian_t is the reference water absorption amount μ t δ is a quantity of change that changes periodically with respect to . In particular, it is a quantity of change that changes over time, more specifically, it is a quantity of change that changes regularly within a 24-hour cycle. Plants, like humans, carry out their daily activities based on everyday physiological phenomena. For example, just as humans eat at regular times throughout the day, plants also actively absorb water at regular times throughout the day. These regular changes that occur on a daily basis are called the quantity of change δ circadian_t The word circadian means "having a 24-hour cycle."

[0031] Next, we will explain the formula (2). Formula (2) is the standard water absorption amount μ t This is the formula for finding

[0032] β0 to β3 are adaptive parameters determined by experiments or the like, and are stored in advance in the calculation unit 3 as constant values.

[0033] X DASt is the elapsed time from the sowing of the plant to a specific time point, and constitutes the time information mentioned above. The specific time point is the time point at which it is desired to obtain the amount of water absorption as an estimated value, that is, the desired time point. In this embodiment, the elapsed time X DASt The unit is seconds (sec). However, this unit is arbitrary and may be hours, days, etc. DAS is an abbreviation for "Day After Sowing."

[0034] Elapsed time X DASt The longer the time, the faster the plant grows and the standard water absorption amount μ t Since the standard water absorption amount μ t When calculating the elapsed time X DASt is included in the calculation.

[0035] X FW is the initial weight of a plant at the start of cultivation, also called fresh weight or initial live weight. This initial weight is measured, for example, by an operator using a weighing scale. However, the initial weight does not necessarily have to be measured, and a commonly known weight may be used. The start of plant cultivation refers to the time when germinated seeds are first placed in a nutrient solution tank, which is a time after the seeds are sown on a water-absorbing sponge or the like.

[0036] Initial weight FW The heavier the plant, the greater the initial growth rate, and the lower the standard water absorption amount μ t Since the standard water absorption amount μ t When calculating the initial weight X FW is included in the calculation.

[0037] X VPDt is a parameter related to the plant's growth environment, more specifically, the vapor deficit (Pa) in the plant's growth environment. VPDt In this embodiment, the saturation deficit in the factory is controlled to be within an optimum range, so a predetermined value within the optimum range is set as the saturation deficit X VPDtGenerally, the saturation deficit VPD (kPa) is calculated by the temperature T (℃) and relative humidity h r Based on this (%), it can be calculated using the following formula (5).

[0038]

number

[0039] As is well known, the vapor pressure deficit is an important parameter that determines the growth rate of plants, and there is an optimum range for it. Therefore, in this embodiment, the vapor pressure deficit value in the factory is controlled to a predetermined value within such an optimum range. The standard water absorption amount μ t When calculating the saturation deficit X VPDt is included in the calculation.

[0040] Next, we will explain the formula (3). The formula (3) is the increment δ LDt This is the formula for finding

[0041] β4 is a fitting parameter determined by an experiment or the like, and is stored in advance in the calculation unit 3 as a constant value.

[0042] X LDt is a parameter that represents the lighting state of the lighting device 52, i.e., a lighting parameter. LDt constitutes the aforementioned environmental information and lighting information. When the light is on, X LDt = 1, and when the light is off, X LDt = 0. As mentioned above, plants are active when light is irradiated, so the amount of water absorbed increases. Therefore, when light is irradiated, that is, when the light is on, X LDt = 1, the water absorption amount α t When calculating the increase δ LDt On the other hand, when there is no light, that is, when the lights are off, X LDt = 0, and the water absorption amount α t The increase in δ LDt is effectively prevented from being added.

[0043] Next, we will explain the formula (4). The formula (4) is the change amount δ circadian_t This is the formula for finding

[0044] β5 and β6 are adaptive parameters determined by experiments or the like, and are stored in advance in the calculation unit 3 as constant values.

[0045] In equation (4), the sine term changes between 1 and -1 within 24 hours. Therefore, the change δ accurately reflects the periodic change in water absorption that occurs during the day. circadian_t can be obtained.

[0046] Next, a water absorption amount estimation method using the water absorption amount estimation device 1 of this embodiment will be described in more detail.

[0047] In the input step S1 shown in FIG. 2, the operator inputs data using the input unit 2. At this time, the operator inputs the elapsed time X DASt and initial weight X FW and the lighting parameters at a particular time, X LDt and the saturation deficit at a specific point in time X VPDt Enter the values ​​for and .

[0048] As will be described in more detail later, the lighting device 52 turns on and off in a 24-hour cycle according to a predetermined schedule, as shown in FIG. LDt As mentioned above, the saturation deficit in the factory is managed, so the saturation deficit X VPDt can be entered.

[0049] The lighting and extinguishing schedule of the lighting device 52 is stored in the lighting device 52. Therefore, as shown in FIG. 1, the lighting device 52 is connected to the calculation unit 3, and the lighting and extinguishing schedule is output from the lighting device 52 to the calculation unit 3. The lighting parameter X at a specific time point is calculated by the calculation unit 3 according to the lighting and extinguishing schedule. LDt The value of may be determined.

[0050] When the data input is completed in this way, the calculation unit 3 calculates the reference water absorption amount μ at a specific time point from the formula (2) in the calculation step S2. t Calculate (or estimate, the same below) the increase amount δ at a specific time from equation (3). LDt Calculate the change amount δ at a specific time from equation (4). circadian_t Then, from equation (1), the amount of water absorption at a specific time α t The result of this calculation is the amount of water absorption α t is the amount of water absorption as an estimated value that is desired to be calculated. The calculation unit 3 calculates these reference water absorption amounts μ t , increase amount δ LDt , the change amount δ circadian_t and water absorption amount α t Each value of is output to the output unit 4.

[0051] Next, in an output step S3, the output unit 4 outputs each value, specifically, displays it on the monitor 4A. t Not only that, but also the standard water absorption amount μ t , increase amount δ LDt and the change amount δ circadian_t Each value is also output or displayed, allowing you to understand the calculation results in detail.

[0052] Next, the accuracy of the water absorption amount estimation device 1 and the water absorption amount estimation method of this embodiment will be described.

[0053] FIG. 3 shows the actual value (horizontal axis) obtained by actually measuring the amount of water absorption, and the estimated value of the amount of water absorption α estimated by the device 1 and method of this embodiment. t 10 is a graph showing the accuracy between (vertical axis).

[0054] Line a is the 100% line where the two completely match. The estimated values ​​obtained in Experiments 1 to 6 (denoted as Exp. 1 to 6) are generally concentrated near the 100% line a, which shows that the device 1 and method of this embodiment have relatively high accuracy. Note that Experiments 1 and 2 are data when the environmental humidity was 70%, Experiments 4 and 5 are data when the environmental humidity was 80%, and Experiments 3 and 6 are data when the environmental humidity was 90%.

[0055] Figure 4 is a time chart showing the time transition of actual values ​​(black circles) and estimated values ​​(dashed lines). The lower horizontal axis represents the number of days (days) after sowing the plants until a specific time point, which is the elapsed time x DASt The upper horizontal axis is time (hours) and the vertical axis is water absorption (g / h).

[0056] In the figure, the hatched time periods are the time periods when the lights are off, i.e., dark period D. The unhatched time periods are the time periods when the lights are on, i.e., light period B. Dark period D and light period B occur at the same times every day. Dark period D is set to the middle of the night, including midnight.

[0057] The example shown is the result when the environmental humidity was set to 70%.

[0058] This figure also shows that the estimated values ​​are generally close to the actual values, and that the accuracy of the device 1 and method of this embodiment is relatively high.

[0059] In both the estimated and actual values, the amount of water absorption tends to increase as the number of days after sowing increases, and tends to be higher in light period B than in dark period D. Furthermore, within light period B, the amount of water absorption tends to be maximum around the middle of the period (12:00).

[0060] Figure 5 is a time chart similar to Figure 4, showing the results when the environmental humidity was set to 80%. In this case, the results were almost the same as those in Figure 4.

[0061] Figure 6 is a time chart similar to Figure 4, showing the results when the environmental humidity was set to 90%. In this case, the results were almost the same as those in Figure 4. However, compared to Figure 4, there is a tendency for the increase or decrease in water absorption during one light period B to be smaller.

[0062] As described above, the water absorption estimation device 1 and the water absorption estimation method of this embodiment can accurately estimate the water absorption value at a specific point in time, which changes over time.

[0063] The water absorption amount estimation device 1 and the water absorption amount estimation method of this embodiment are used to estimate the water absorption amount α t Therefore, the predicted water absorption amount α t This data can be suitably used for the design of plant factories, etc.

[0064] Although the water absorption amount estimation device of this embodiment has been described in detail above, various modifications of the water absorption amount estimation device are conceivable.

[0065] (1) For example, in the above embodiment, the vapor deficit X VPDt I entered the value of saturation deficit X VPDt may be calculated in the calculation unit 3 and calculation step S2. In this case, the saturation deficit X VPDt The temperature T (℃) and relative humidity h of the growing environment required for the calculation r (%) is inputted by the input unit 2 in the input step S1, and these temperature T and relative humidity h r Based on the value of the saturation deficit X, the calculation unit 3 and calculation step S2 calculate the saturation deficit X according to equation (5). VPDt Just calculate it.

[0066] At this time, the temperature in the plant factory is controlled to an optimum predetermined temperature, so the temperature T (℃) should be set to that predetermined temperature. r Alternatively, as shown in Figure 1, the temperature T and relative humidity h of the growing environment can be calculated. r A thermo-hygrometer 61 for measuring the temperature T and relative humidity h is installed in the plant factory and connected to the calculation unit 3. r Based on the saturation deficit x VPDt may be calculated.

[0067] (2) In the above embodiment, the elapsed time X DASt I entered the value directly, but the elapsed time X DAStmay be calculated in the calculation unit 3 and calculation step S2. In this case, the elapsed time X DASt The date and time of sowing the plants and the date and time of the specific time point, which are necessary for calculating the above, are input by the input unit 2 in the input step S1, and the calculation unit 3 and the calculation step S2 calculate the elapsed time X based on these dates and times. DASt Just calculate it.

[0068] (3) Of the input data, a constant value that does not change over time may be stored in the calculation unit 3 after input, and the stored value may be read and used for each estimation. Such input data may include, for example, the initial weight X FW and saturation deficit X VPDt At least one of the above can be mentioned.

[0069] It would be extremely useful if it were possible to automatically diagnose whether the growth state of plants grown in a plant factory is normal. The inventors have come up with the idea of ​​a device for performing such an automatic diagnosis using the water absorption amount estimation device described above, and the details of this device will be described below.

[0070] 1, a plant growth condition diagnosis device 70 according to this embodiment includes the water absorption amount estimation device 1 and a diagnosis unit 71. The diagnosis unit 71 is configured by the same personal computer main body 3A as the calculation unit 3. However, the diagnosis unit 71 may be configured separately from the calculation unit 3.

[0071] The diagnosing unit 71 is configured to perform a diagnosis each time water is supplied by the water supply device 57. That is, the diagnosing unit 71 calculates the accumulated water absorption amount at the current water supply time by accumulating the water absorption amounts estimated by the water absorption amount estimation device 1 from the previous water supply time to the current water supply time. The diagnosing unit 71 also calculates the actual water absorption amount of the plant at the current water supply time by subtracting the amount of evaporation that occurred between the previous water supply time and the current water supply time from the amount of water supplied at the current water supply time. Finally, the diagnosing unit 71 compares the accumulated water absorption amount with the actual water absorption amount at the current water supply time to determine whether the plant's growth condition is normal.

[0072] This will be described in detail below. The diagnosis unit 71 calculates the integrated water absorption amount Iα(g) from the following equation (6) stored in advance.

[0073]

number

[0074] D0 is the previous water supply time, and D1 is the current water supply time. Here, one water supply starts when the water supply valve 59 opens and ends when the water supply valve 59 closes. The time required for this one water supply, that is, the opening time of the water supply valve 59 from opening to closing, is extremely short. In this embodiment, for convenience, the time when the water supply valve 59 closes is defined as the water supply time. The water supply time for each water supply is stored in the diagnosis unit 71.

[0075] α t is the amount of water absorption estimated by the calculation unit 3 at a plurality of specific time points between the previous water supply time D0 and the current water supply time D1 (referred to as the water supply interval). t The faster the water absorption rate of the plant, that is, the faster the water absorption rate α t The larger the value, the shorter the water supply interval. t The integration is performed assuming that the value is constant at a specific point in time.

[0076] The cumulative water absorption Iα is a reference value for the amount of water a plant is expected to absorb between watering intervals under normal conditions. By comparing this cumulative water absorption Iα with the actual amount of water absorption by the plant, it is possible to accurately determine whether the actual amount of water absorption is normal, i.e., whether the plant's growth is normal.

[0077] Next, the diagnosis unit 71 calculates the actual water absorption amount Iact(g), which is the actual amount of water absorption by the plant, from the following equation (7) stored in advance.

[0078]

number

[0079] S is the amount of water (g) supplied in the current water supply period. A is the exposed area of ​​the culture solution 54 to the air (m 2 ) Since this exposed area A is physically determined, the value is input as a constant value to the diagnosis unit 71 by the input unit 2 and stored in the diagnosis unit 71.

[0080] E t is the instantaneous evaporation amount (g / m 2 h). This instantaneous evaporation amount E t is calculated from the following equation (8) which is stored in advance.

[0081]

number

[0082] VPD t is the saturation deficit (kPa) as an instantaneous value. In this embodiment, a thermo-hygrometer 61 is connected to the calculation unit 3, and the temperature T and relative humidity h measured by this are used as the r Based on the vapor pressure deficit VPD t is calculated using equation (5).

[0083] The water supply amount S is the amount of water actually supplied by the water supply device 57 during the current water supply period D1. As shown in FIG. 1, the flow meter 60 is connected to the diagnostic unit 71. The diagnostic unit 71 calculates the water supply amount S by integrating the flow rate measured by the flow meter 60 while the water supply valve 59 is open. Alternatively, in the case of a flow meter 60 with a flow rate integration function, the integrated flow rate measured by the flow meter 60 may be used as the water supply amount S.

[0084] The second term of equation (7) is the unit area (m 2 ) and instantaneous evaporation per unit time (h) E t (g) during the water supply interval (h), and add this to the exposed area A (m 2 ) Therefore, the second term means the amount of evaporation of the culture solution 54 into the atmosphere during the water supply interval (h).

[0085] (7) Since the right side of the equation is the value obtained by subtracting the evaporation amount from the water supply amount S, it represents the net amount of the culture solution 54 that has decreased due to the water absorption of the plant during the water supply interval, that is, it represents the amount of the culture solution 54 that the plant has actually absorbed during the water supply interval. Therefore, in this embodiment, this is defined as the actual water absorption amount Iact and is used as a comparison target with the integrated water absorption amount Iα, which is the evaluation reference value.

[0086] Next, the diagnosis unit 71 compares the integrated water absorption amount Iα and the actual water absorption amount Iact. In this embodiment, when the actual water absorption amount Iact is greater than or equal to the integrated water absorption amount Iα (Iact≧Iα), the diagnosis unit 71 determines that the growth state of the plant is normal. On the other hand, when the actual water absorption amount Iact is less than the integrated water absorption amount Iα (Iact<Iα), the diagnosis unit 71 determines that the growth state of the plant is abnormal.

[0087] When the actual water absorption amount Iact is greater than or equal to the integrated water absorption amount Iα (Iact≧Iα), it is considered that the plant is absorbing water as much as or more than expected, and it is considered that the plant is healthy and has no growth problems. Therefore, the growth state of the plant is determined to be normal.

[0088] Conversely, when the actual water absorption amount Iact is less than the integrated water absorption amount Iα (Iact<Iα), it is considered that the water absorption amount of the plant is less than expected and there are growth problems. Therefore, the growth state of the plant is determined to be abnormal.

[0089] In particular, the reference water absorption amount μ t Since the equation (2) for obtaining is based on the premise that no growth restriction occurs, when the actual water absorption amount Iact is less than the integrated water absorption amount Iα, it is suggested that some growth restriction may have occurred. Therefore, in this case, the growth state is determined to be abnormal. This makes it possible to detect and eliminate the abnormal state at an early stage and prevent the subsequent expansion of the abnormal state.

[0090] When the diagnosis result is obtained in this way, the diagnosis unit 71 outputs the diagnosis result to the output unit 4. The output unit 4 displays the diagnosis result on the monitor 4A.

[0091] Although the growth condition diagnosis device of this embodiment has been described in detail above, various modifications of the growth condition diagnosis device are conceivable.

[0092] For example, when comparing the integrated water absorption Iα with the actual water absorption Iact, taking into consideration a judgment error, the actual water absorption Iact may be compared with the value (Iα-δ) obtained by subtracting a predetermined value δ from the integrated water absorption Iα. In this case, if Iact≧(Iα-δ), it is judged to be normal, and if Iact<(Iα-δ), it is judged to be abnormal.

[0093] The configurations of the above-described embodiments and variations can be combined in part or in whole unless there is a particular contradiction. The embodiments of the present disclosure are not limited to the above-described embodiments, and all variations, applications, and equivalents encompassed within the spirit of the present disclosure as defined by the claims are included in the present disclosure. Therefore, the present disclosure should not be interpreted as being limited, and can be applied to any other technology that falls within the spirit of the present disclosure. [Explanation of symbols]

[0094] 1 Water absorption amount estimation device 2 Input section 3 Arithmetic section 4 Output section 70 Growth condition diagnostic device 71 Diagnostic Department 51 Plants 54 Culture solution 55 Culture medium tank 57 Water supply equipment

Claims

1. An apparatus for estimating the amount of water absorption of plants grown in a plant factory, a calculation unit that estimates the amount of water absorption per unit time of the plant at a specific time point based on environmental information on the growing environment of the plant, an initial weight of the plant at the start of cultivation, and time information on the elapsed time from the sowing of the plant to the specific time point, the environmental information includes saturation deficit information relating to a saturation deficit of the growing environment and lighting information relating to a lighting state of lighting, the calculation unit estimates a reference water absorption amount per unit time of the plant at the specific time point based on the saturation deficit information, the initial weight, and the time information; the calculation unit estimates an increase in the amount of water absorption relative to the reference amount of water absorption at the specific time point based on the reference amount of water absorption, the saturation deficit information, and the illumination information; the calculation unit estimates a value of a change amount that periodically changes with respect to the reference water absorption amount at the specific time point based on the reference water absorption amount, the saturation deficit information, and the time information; the calculation unit estimates the water absorption amount at the specific time point based on the reference water absorption amount, the increase amount, and the change amount at the specific time point; The specific time points are a plurality of time points included in a 24-hour period, the increase amount is 0 when the lighting devices of the plant factory are turned off, and the value of the change amount is a value that periodically changes between a positive value and a negative value within one 24-hour period. A plant water absorption estimation device characterized by:

2. 10. A diagnostic device comprising the water absorption estimation device according to claim 1, for diagnosing a growth state of a plant based on the water absorption amount estimated by the water absorption estimation device, The plant factory includes a culture solution tank that stores a culture solution for hydroponic cultivation of plants, and a water supply device that supplies an equal amount of water to the culture solution tank every time a predetermined amount of the culture solution in the culture solution tank decreases, The diagnostic device performs the following during the current water supply period: The water absorption amount estimating device calculates an integrated water absorption amount by integrating the water absorption amount values ​​estimated from the previous water supply time to the current water supply time; The actual amount of water absorbed by the plant is calculated by subtracting the amount of water evaporated between the previous watering and the current watering period from the amount of water supplied during this watering period. A diagnostic unit is provided which compares the integrated amount of water absorption with the actual amount of water absorption to determine whether the plant is growing normally. A plant growth condition diagnostic device characterized by:

Images