JP7185233B2 - PLANT COMMUNITY TRANSMITTED LIGHT SENSOR UNIT AND METHOD FOR DETERMINING GROWTH OF PLANT - Google Patents

Description

The present invention relates to a plant community transmitted light sensor unit used to accurately determine the growth state of plants, and a plant growth state determination method using the sensor unit.

During the cultivation process of vegetables, flowers, etc., producers observe the growth state of plants every day, and set and change cultivation management conditions (temperature, humidity, fertilizer, etc.) based on subjective evaluation of the growth state (degree of growth, leaf color, etc.). component, amount of liquid supplied, etc.). However, evaluation of the growth state of plants requires a high degree of skill, and producers with little cultivation experience in particular face the problem of destabilization of cultivation due to errors in evaluation. On the other hand, even experienced producers face similar problems in order to respond quickly to recent extreme weather changes, new cultivation management techniques (integrated environmental control, etc.), and the introduction of new varieties. Therefore, the construction of an index that can appropriately express the growth state of plants will greatly contribute to high-quality and stable production through decision-making support and control automation for cultivation management.

Therefore, an attempt to use the leaf area index (LAI) is known as an index for automatically grasping the growth state of plants as numerical data in a non-destructive and non-contact manner. For example, in Patent Document 1, the applicant of the present application has set up a scattered light sensor inside and outside a plant community, and has developed a "plant growth stage determination method and system" that can evaluate LAI from the degree of attenuation of light in the community in a non-destructive and non-contact manner. providing. In order to cut the direct light from inside and outside the plant community and measure only the amount of scattered light, the scattered light sensor with its surroundings except the front side of the light-receiving surface shaded is oriented toward the north where the influence of direct sunlight is small. A total of two sensors are installed, one inside and one outside the canopy, and the larger the difference in the sensor output in the canopy with respect to the sensor output in the canopy, the larger the LAI is determined.
Further, Patent Document 2 discloses an invention capable of non-destructive evaluation of LAI and photosynthetic activity based on the transmitted light ratio by wavelength of a plant community using a sensor that senses visible light and near-infrared light. This is because the greater the LAI of a plant community, the more visible light is absorbed by chlorophyll and attenuated more. is.

Japanese Patent No. 4991990 Japanese Patent No. 5410323

In the "plant growth stage determination method and system" described in Patent Document 1, the light receiving surface is only in the north direction and the light receiving range is small. There is concern that foliage close to the edge may block the sensor opening and overestimate the LAI. In addition, a total of two scattered light sensors are required inside and outside the plant colony, and installation is complicated, resulting in an increase in introduction cost. Furthermore, there is also the problem that physiological functions other than LAI (chlorophyll content in leaves, photosynthetic activity, etc.) cannot be evaluated.
On the other hand, with the sensor described in Patent Document 2, it is possible to evaluate under conditions where the community structure is sufficiently formed and direct light does not enter the community. The ratio of near-infrared light to visible light fluctuates greatly under the cultivation conditions of vegetables and flowers, where direct light may enter the small plant community, making it difficult to obtain a stable value. In fact, the ratio of near-infrared light and visible light of strawberries and gerberas obtained using a near-infrared/visible light sensor covered with a light diffusing material facing upward varies greatly, and the growth state (LAI) etc. Almost no correlation was observed.

Therefore, the present invention has a low-cost configuration, even under cultivation conditions such as vegetables and flowers where direct light may enter the plant community, and physiological functions including LAI (chlorophyll content of leaves, It is an object of the present invention to provide a plant colony transmitted light sensor unit and a method for determining the growth state of a plant, which can stably determine the growth state of the plant even if the plant growth state is low (photosynthetic activity, etc.).

In order to achieve the above object, the invention according to claim 1 comprises a visible light sensor for detecting visible light and a near-infrared light sensor for detecting near-infrared light to determine the growth state of a plant. A plant community transmitted light sensor unit used for
It includes a transparent pipe and a pair of black cover plates closing both ends of the pipe, and a visible light sensor and a The near-infrared light sensor is attached with the light receiving surface facing downward.
The term "growing state" used in the present invention includes physiological functions such as leaf chlorophyll content and photosynthetic activity, in addition to growth stages such as LAI and degree of growth. same as below.
The invention according to claim 2 is the structure according to claim 1, characterized in that the cover plate is a square of 3 cm to 7 cm square, and the length of the pipe is approximately 10 cm.
In addition, "approximately 10 cm" is meant to include 10 cm and include slight errors before and after that.
In order to achieve the above object, the invention according to claim 3 is a method for determining the growth state of a plant,
The plant community transmission light sensor unit according to claim 1 or 2 is set in a plant community in a vertical position in which the pipe stands upright, and scattered light incident from around the pipe is detected by a visible light sensor and a near-infrared light sensor. , the ratio of near-infrared light and visible light in a predetermined time period is calculated, and the growth state corresponding to the ratio is determined.
In order to achieve the above object, the invention according to claim 4 comprises a visible light sensor for detecting visible light and a near-infrared light sensor for detecting near-infrared light to determine the growth state of a plant. A plant community transmitted light sensor unit used for
A transparent pipe, a pair of black cover plates that close both ends of the pipe, and a pair of black cover plates that are laid between the cover plates above and below the pipe when the pipe is laid down horizontally and overlap the pipe in the vertical direction. 2 cover plates, and a visible light sensor and a near-infrared light sensor are provided at the inner central portion of the pipe on the surface of the pipe mounting side of one of the cover plates in a state where the pipe is laid down in the horizontal direction, It is characterized in that each of them is attached with its light receiving surface facing the other cover plate.
The invention according to claim 5 is the structure according to claim 4, characterized in that the width of the second cover plate is approximately 7 cm, and the length of the pipe is 5 cm to 10 cm.
In addition, "approximately 7 cm" is intended to include 7 cm and include slight errors before and after it.
In order to achieve the above object, the invention according to claim 6 is a method for determining the growth state of a plant,
6. The plant colony transmission light sensor unit according to claim 4 or 5 is set in a plant colony in a sideways posture in which the pipe is lodged, and scattered light incident from the side of the pipe is detected by a visible light sensor and a near-infrared light sensor. , the ratio of near-infrared light and visible light in a predetermined time period is calculated, and the growth state corresponding to the ratio is determined.

According to the present invention, a plant community transmitted light sensor unit is installed in a plant community in facilities such as vegetables and flowers, and outdoor cultivation (including artificial light). By calculating the ratio to visible light), the growth state of the plant (degree of growth, LAI, photosynthetic activity, etc.) can be grasped in a non-destructive and non-contact manner.
In particular, the ratio of near-infrared light to visible light measured by this sensor unit not only indicates the size and extent of growth of a plant such as LAI, but also reflects the photosynthetic function of the foliage. area” is expressed. Therefore, by numerically grasping the growth state of the plant with this sensor unit, the producer can judge the appropriateness of environmental conditions and cultivation management such as nutrient and moisture control for the current growth state. By adjusting and changing cultivation management based on this determination of suitability, it becomes possible to maximize the yield and quality of vegetables and flowers according to the purpose of production.
In addition, since the invention has a simple structure, is compact, and can utilize inexpensive photodiodes, it is expected to be put into practical use at low cost. contribute greatly to the promotion of
In particular, according to the inventions described in claims 2 and 5, in addition to the above effects, by specifying the size of the sensor unit, it is possible to measure the ratio of near-infrared light and visible light stably with small fluctuations. .

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of a plant colony transmission light sensor unit, (A) shows a perspective view, (B) shows a vertical cross section, respectively. FIG. 2 is an explanatory diagram of a determination system using the sensor unit of FIG. 1; It is explanatory drawing of the other example of a plant colony transmission light sensor unit, (A) shows a perspective view, (B) shows a cross section, respectively. 1 is a graph showing the relationship between cucumber LAI and near-infrared light/visible light ratio under an artificial light source. It is a graph which shows transition of the near-infrared light/visible light ratio in Gerbera cultivars. It is a graph which shows the relationship between the near-infrared light/visible light ratio and LAI in gerbera cultivation. It is a graph which shows transition of near-infrared light/visible light ratio in strawberry cultivation. It is a graph which shows transition (moving average of 3 days) of near-infrared light/visible light ratio in strawberry cultivation. It is a graph which shows the relationship between near-infrared light / visible light ratio (3-day moving average) and LAI in strawberry cultivation. It is a graph which shows transition of near-infrared light/visible light ratio by difference in data utilization time in tomato cultivation. It is a graph which shows transition of near-infrared light/visible light ratio by change of light intensity in strawberry cultivation.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Description of Plant Community Transmitted Light Sensor Unit]
FIG. 1 is an explanatory view showing an example of a plant colony transmitted light sensor unit (hereinafter simply referred to as "sensor unit") 1, in which (A) shows a perspective view and (B) shows a longitudinal section.
This sensor unit 1 comprises a pair of upper and lower cover plates 3 and 4 which are square in plan view and are colored in black on both ends of a transparent cylindrical pipe 2 made of acrylic or the like. The diameter of the pipe 2 is smaller than one side of the cover plates 3,4. Inside the pipe 2 at the center of the lower surface of the upper cover plate 3, there are a sensor for detecting visible light (hereinafter referred to as "visible light sensor") 5 using a photodiode or the like, and a sensor for detecting near-infrared light (hereinafter " 6 are fixed with their light receiving surfaces facing downward.

As shown in FIG. 2, the sensor unit 1 is set in the plant colony P with the cover plate 3 facing up and the pipe 2 standing upright. is cut. Therefore, scattered light incident from the periphery of the pipe 2 can be effectively measured. Here, visible light is absorbed by the chlorophyll of plants and attenuated, and the ratio of near-infrared light, which absorbs less, increases.
In this determination system S, the outputs of the sensors 5 and 6 are input to a computing section 10 provided in an external personal computer or the like via cables 7 and 7 . The calculation unit 10 calculates the average value in a predetermined time period, calculates the ratio of near-infrared light to visible light (hereinafter referred to as the “near-infrared light/visible light ratio”), and stores it in the storage unit 11 . stored in However, the time period can be arbitrarily changed, and the ratio of integrated values may be used instead of the ratio of average values.

Also, FIG. 3 is an explanatory diagram showing another example of the sensor unit. In this sensor unit 1A, a pipe 2A longer than the sensor unit 1 is used horizontally, and cover plates 3 and 4 are vertically attached to both ends of the pipe 2A. The relationship of height is the same as that of the sensor unit 1 . Therefore, the visible light sensor 5 and the near-infrared light sensor 6 are fixed to the cover plate 3 in a sideways orientation with their light receiving surfaces facing the cover plate 4 .
Further, a pair of rectangular black cover plates 8, 8 connecting the upper and lower sides of the cover plates 3, 4 are provided above and below the pipe 2A. The cover plates 8, 8 overlap the pipe 2A in the vertical direction, so that only the side surfaces of the pipe 2A are exposed.
In this sensor unit 1A, by setting one of the cover plates 8, 8 downward and setting the pipe 2A in the sideways position shown in FIG. be cut. Therefore, the scattered light incident from the left and right side surfaces of the pipe 2A can be effectively measured. The connection between the calculation unit 10 and the storage unit 11 is the same as in the determination system S of FIG.
Hereinafter, when distinguishing between the sensor units 1 and 1A, the sensor unit 1 will be referred to as the "vertical sensor 1" and the sensor unit 1A will be referred to as the "horizontal sensor 1A."

[Verification of the relationship between each sensor and LAI]
FIG. 4 is a graph verifying the relationship between the LAI of cucumbers cultivated with water under an artificial light source (white LED) and the near-infrared light/visible light ratio.
On the left is a vertical sensor with a pipe 2 length of 5 cm and cover plates (blackboards) 3 and 4 of 5 cm square (as a visible light sensor, a visible light photodiode S1133 manufactured by Hamamatsu Photonics is used as a near-infrared light sensor. Near-infrared light photodiode S6775-01 manufactured by Hamamatsu Photonics Co., Ltd. is used) 1 and a horizontal sensor 1A with a pipe 2 length of 15 cm and cover plates 3 and 4 of 3 cm square. , y(LAI) is represented by a linear function of x (ratio of near-infrared light/visible light). This relational expression is stored in the storage section 11 by setting different constants for each plant, and is calculated by the calculation section 10 . R is the correlation coefficient and ^R2 is the contribution rate.
On the right, a visible light sensor 5 and a near-infrared light sensor 6 are installed with their light receiving surfaces facing upward and covered with a light scattering material (here, a ping-pong ball divided in half) (hereinafter referred to as a "control sensor"). ) is used.
As is clear from this graph, both the vertical and horizontal sensors 1 and 1A showed a linear correlation between the near-infrared light/visible light ratio and the cucumber LAI. On the other hand, in the control sensor, when the leaf was covered, the value changed suddenly, and the relationship with LAI changed. As described above, it was confirmed that the growth state determination method using the vertical/horizontal sensors 1 and 1A enables highly accurate non-destructive evaluation of LAI (determination of growth state).

FIG. 5 shows the transition of the near-infrared light/visible light ratio measured using the same horizontal sensor 1A and the control sensor as in FIG. ), showing the average value for the time period from 11:55 to 12:05 on each day.
FIG. 6 shows the relationship between the near-infrared light/visible light ratio and LAI in FIG.
As is clear from these graphs, even in the horizontal sensor 1A, the near-infrared light/visible light ratio and LAI show a correlation, and the near-infrared light/visible light ratio enables non-destructive evaluation of LAI. It turned out to be possible. In addition, in FIG. 5, although the near-infrared light/visible light ratio temporarily decreases in November and December, there is no significant change in the leaf area. This is due to yellowing of leaves due to nutrient deficiency. Thus, it was confirmed that the ratio of near-infrared light/visible light varies depending not only on LAI but also on the physiological functions of plants. On the other hand, in the control sensor, the relationship between the near-infrared light/visible light ratio and the LAI is not as close as in the horizontal sensor 1A.

FIG. 7 shows the transition of the near-infrared light / visible light ratio measured using the same vertical sensor 1 and the control sensor as in FIG. 4 in strawberry cultivation (October 2, 2018 to March 11, 2019) , and shows the average value for the time period from 11:55 to 12:05 on each day. The vertical sensor 1 is on the top, and the control sensor is on the bottom.
In addition, FIG. 8 is the average of the data of each day for a total of three days including the two days before the relevant day in the data of FIG. there is
Further, FIG. 9 shows the relationship between the ratio of near-infrared light/visible light in FIG. 8 and LAI, with vertical sensor 1 on the left and reference sensor on the right.

As is clear from these graphs, the vertical sensor 1 also shows a correlation between the near-infrared light/visible light ratio and LAI, and the non-destructive evaluation of LAI is performed by the near-infrared light/visible light ratio. It turned out to be possible. In particular, in the 3-day average data of FIG. 8, the dynamics of the near-infrared light/visible light ratio could be clarified. The near-infrared light/visible light ratio of the vertical sensor 1 temporarily decreased in early November, early February, and early March. Therefore, it is recognized that it is possible to determine whether the lower lobe has been removed. Also, the ratio of near-infrared light/visible light after mid-January tended to decrease, but there was no significant change in leaf area. Since browning of the leaves was observed during this period due to the supply trouble of some fertilizer components, it is considered that physiological disorders can also be detected.
In addition, in FIG. 9, a very close correlation was found between the near-infrared light/visible light ratio (three-day moving average value) obtained by the vertical sensor 1 and the strawberry LAI. On the other hand, the near-infrared light/visible light ratio by the control sensor did not increase in October, but increased from November onwards, but there were occasional large fluctuations. Not as close as 1.

[Verification of the relationship between data usage time and near-infrared light/visible light ratio]
In the above verification, the data was used only around noon, but we verified how it differs from the near-infrared light/visible light ratio obtained over a wide range of time periods during the day.
FIG. 10 shows two vertical sensors (vertical installation 1, vertical installation 2, pipe length: 10 cm, cover plate (blackboard): 5 cm square) in the plant community in the long-stage cultivation of tomatoes. 5 is a graph showing changes in the measured near-infrared light/visible light ratio (January 5, 2019 to May 15, 2019). Here, the top shows the data usage time around noon (11:55-12:05 (10 points/day)), the bottom shows the data usage time during the day (8:00-16:00 (480 points/day) )).
From these measurement results, it is clear that when measuring under cultivation conditions such as tomatoes that are tall and do not have a leaf layer above the sensor, it is better to use data only during the hours before noon when light shines in from above. It was found that averaging over a wide range using data from the middle time period allows for stable measurement with less fluctuation.

[Verification of the relationship between the weather-dependent light intensity (PPFD) and the ratio of near-infrared light/visible light]
The influence of the weather (light intensity (PPFD)) on the near-infrared light/visible light ratio was verified.
FIG. 11 shows a vertical sensor (vertical installation, pipe length: 10 cm, cover plate (blackboard): 5 cm square) and a horizontal sensor (horizontal installation, pipe length: 15 cm) in a plant community in strawberry cultivation. , The width of the cover plate (upper blackboard): 7 cm) and a light intensity (PPFD) sensor are installed, and the near-infrared light / visible light ratio and the light intensity (PPFD) in the greenhouse are continuously measured (March 2019 It is a graph measured from May 16 to May 5, 2019). The top is the data of the light intensity sensor, the middle is the data of the horizontal sensor, and the bottom is the data of the vertical sensor.
From this measurement result, it was found that the near-infrared light/visible light ratio tends to increase when the light intensity in the greenhouse is extremely low due to weather fluctuations for both vertical and horizontal sensors. . Therefore, by canceling the near-infrared light/visible light ratio data on a cloudy rainy day when the light intensity is extremely low, it is possible to make an appropriate evaluation.

[Verification of relationship between sensor unit size, sensor output, and near-infrared light/visible light ratio]
In order to clarify the structure of the sensor unit that can stably measure the ratio of near-infrared light/visible light, we changed the size of the cover plate and pipe in three patterns, and each pattern affects the sensor output and the coefficient of variation (cv). Considered the impact.
1. The length of the vertical sensor pipe (height of the sensor) is set to 5 cm, and the size of the upper and lower cover plates is changed to 3 stages (3 cm square, 5 cm square, 7 cm square). height of about 13 cm), and the outputs of the visible light sensor and the near-infrared light sensor were measured and recorded at intervals of 1 minute (March 20 to 29, 2019). The average value (8:00 to 16:00) and the coefficient of variation (cv: standard deviation/average value×100%) for each measured sensor output were obtained. The results are shown in Table 1 below.

From Table 1, it was found that the output of the visible light sensor increased and the output of the near-infrared light sensor decreased as the size of the cover plate increased. In addition, the c.v. of the visible light sensor was slightly smaller at 5 cm square than those of 3 cm square and 7 cm square, and the c.v. of the near-infrared light sensor tended to increase as the size increased. The near-infrared light/visible light ratio, which is an index of the growth state, decreased as the size of the cover plate increased, but there was no significant difference in the c.v.

Next, the size of the cover plate was set to 5 cm square, and the length of the pipe was changed in three steps (5 cm, 10 cm, 15 cm). The output was measured and recorded at 1-minute intervals, and the coefficient of variation was obtained. The results are shown in Table 2 below.

From Table 2, it was found that the output of the visible light sensor was larger for pipe lengths of 15 cm than 5 cm and 10 cm, and the output of the near-infrared light sensor tended to increase as the pipe length increased. In addition, cv tended to be larger than 10 cm and 15 cm for a pipe length of 5 cm with a visible light sensor, and tended to decrease with a longer pipe length with a near-infrared light sensor. The near-infrared light/visible light ratio decreased as the pipe length increased, but cv was the smallest at 10 cm.
From the above results, in the vertical sensor, if the size of the cover plate is 3 cm square to 7 cm square, and the length of the pipe (height of the sensor) is 10 cm, a stable near-infrared light/visible light ratio with small fluctuations can be obtained. can be measured.

2. The horizontal sensor pipe length is 15 cm, the width of the upper and lower cover plates is changed in three stages (3 cm, 5 cm, 7 cm), and the output of the visible light sensor and the near infrared light sensor is measured under the same conditions as the vertical sensor. Each was measured and recorded at intervals of 1 minute, and the coefficient of variation was obtained. The results are shown in Table 3 below.

From Table 3, the larger the width of the upper and lower cover plates, the smaller the outputs of the visible light sensor and the near-infrared light sensor, but the c.v. of the near-infrared light sensor showed an increasing tendency. The near-infrared light/visible light ratio increased as the width of the upper and lower cover plates increased, while the c.v. tended to decrease, reaching a minimum value at 7 cm.

Next, the width of the upper and lower cover plates is set to 5 cm, the length of the pipe is changed in three stages (5 cm, 10 cm, and 15 cm), and the outputs of the visible light sensor and the near infrared light sensor are each set to 1 under the same conditions as above. It was measured and recorded every minute, and the coefficient of variation was obtained. The results are shown in Table 4 below.

From Table 4, it can be seen that the outputs of the visible light sensor and the near infrared light sensor tend to be larger at pipe lengths of 15 cm than at pipe lengths of 5 cm and 10 cm, but there was no significant difference in cv due to pipe length. The near-infrared/visible light ratio decreased as the length of the pipe increased, but the cv with a pipe length of 15 cm tended to be slightly larger than the cv with a pipe length of 5 cm and 10 cm.
From the above results, it is recognized that the horizontal sensor can measure the near-infrared light/visible light ratio stably with small fluctuations if the width of the cover plate is 7 cm and the length of the pipe is 5 to 10 cm.

As described above, according to the sensor unit 1 of the above configuration, the transparent pipe 2 and the pair of black cover plates 3 and 4 that close both ends of the pipe 2 are included, and the pipe 2 is erected in the vertical direction. A visible light sensor 5 and a near-infrared light sensor 6 are attached to the inner central portion of the pipe 2 on the lower surface of the upper cover plate 3 in the state, with the light receiving surface facing downward, so that vegetables, flowers, etc. In the facility, outdoor cultivation (including artificial light), the sensor unit 1 is installed in the plant community P, and by calculating the light amount ratio by wavelength (near infrared light / visible light ratio) of the light transmitted through the community P, the plant The growth state (degree of growth, LAI, photosynthetic activity, etc.) can be grasped in a non-destructive and non-contact manner.
In particular, the near-infrared light/visible light ratio measured by the sensor unit 1 not only expresses the size and degree of growth of a plant such as LAI, but also reflects the photosynthetic function of the leaf layer. ” is expressed. Therefore, by numerically grasping the growth state of the plant with the present sensor unit 1, the producer can judge whether the environmental conditions for the current growth state and the adequacy of cultivation management such as nutrient and moisture control. By adjusting and changing cultivation management based on this determination of suitability, it becomes possible to maximize the yield and quality of vegetables and flowers according to the purpose of production.
In addition, since the sensor unit 1 has a simple structure and a small size, and can utilize an inexpensive photodiode, it is expected to be put into practical use at low cost, and it is highly likely that it will be widely accepted in the cultivation of vegetables and flowers, and the cultivation will be stabilized. and contribute greatly to the promotion of scale expansion.
That is, according to the sensor unit 1 and the plant growth state determination method of the above configuration, there is a possibility that direct light may enter the plant community P with a low-cost configuration using the near-infrared and visible light sensors 5 and 6. It is possible to stably determine the growth state of plants even under certain cultivation conditions such as vegetables and flowers, and even under physiological functions including LAI (chlorophyll content in leaves, photosynthetic activity, etc.).

Similarly, according to the sensor unit 1A and the plant growth state determination method using the sensor unit 1A of the above configuration, the transparent pipe 2A, the pair of black cover plates 3 and 4 closing both ends of the pipe 2A, and the pipe A pair of black cover plates 8, 8 (second cover plates) which are laid between the cover plates 3, 4 above and below the pipe 2A with the pipe 2A laid down in the horizontal direction and overlap the pipe 2A in the vertical direction. , and a visible light sensor 5 and a near-infrared light sensor 6 are provided at the inner central portion of the pipe 2A on the surface of the one cover plate 3 on the mounting side of the pipe 2A in a state where the pipe 2A is laid down in the horizontal direction. , are attached with their light receiving surfaces facing the other cover plate 4 . As a result, with a low-cost configuration using the near-infrared and visible light sensors 5 and 6, even under cultivation conditions such as vegetables and flowers where direct light may enter the plant community P, LAI Even with physiological functions (chlorophyll content in leaves, photosynthetic activity, etc.), it is possible to stably determine the growth state of a plant.

Note that the sizes of the pipe and the cover plate are not limited to the numerical values in the above embodiment, and can be changed as appropriate. The cross-sectional shape of the pipe is not limited to circular, but may be oval, oval, hexagonal, octagonal, or other polygonal shape.
Also, the cover plates attached to both ends of the pipe are not limited to being square, but may be rectangular, polygonal, circular, or the like.

1, 1A Plant community transmission light sensor unit 2, 2A Pipe 3, 4 Cover plate 5 Visible light detection sensor 6 Near-infrared light detection sensor 7 Cable, 8.. Cover plate (second cover plate), 10.. Operation unit, 11.. Storage unit, P.. Plant community.

Claims (6)

A plant colony transmitted light sensor unit used for determining the growth state of a plant, comprising a visible light sensor that detects visible light and a near-infrared light sensor that detects near-infrared light,
transparent pipes,
A pair of black cover plates that close both ends of the pipe,
With the pipe standing vertically, the visible light sensor and the near-infrared light sensor are attached to the inner central portion of the pipe on the lower surface of the upper cover plate with their light receiving surfaces facing downward. A plant colony transmitted light sensor unit, characterized in that: 2. The plant colony transmitted light sensor unit according to claim 1, wherein the cover plate is a square of 3 cm to 7 cm square, and the length of the pipe is approximately 10 cm. 3. The plant colony transmitted light sensor unit according to claim 1 is set in a plant colony in a vertical posture in which the pipe stands upright, and scattered light incident from around the pipe is detected by the visible light sensor and the near field light sensor. Measuring with an infrared light sensor, calculating the ratio of near-infrared light and visible light in a predetermined time period, and determining the growth state corresponding to the ratio Method. A plant colony transmitted light sensor unit used for determining the growth state of a plant, comprising a visible light sensor that detects visible light and a near-infrared light sensor that detects near-infrared light,
transparent pipes,
a pair of black cover plates closing both ends of the pipe;
a pair of black second cover plates that are installed between the cover plates above and below the pipe in a state that the pipe is laid down horizontally and overlap the pipe in the vertical direction;
The visible light sensor and the near-infrared light sensor are provided on the inner central portion of the pipe on the surface of one of the cover plates on the mounting side of the pipe while the pipe is laid down in the horizontal direction, respectively. facing the other cover plate. The plant community transmitted light sensor unit according to claim 4, wherein the width of the second cover plate is about 7 cm, and the length of the pipe is 5 cm to 10 cm. 6. The plant colony transmitted light sensor unit according to claim 4 or 5 is set in a plant colony in a sideways posture in which the pipe is lodged, and scattered light incident from the side of the pipe is detected by the visible light sensor and the near field light sensor. Measuring with an infrared light sensor, calculating the ratio of near-infrared light and visible light in a predetermined time period, and determining the growth state corresponding to the ratio Method.

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