JP2019180252A - Plant cultivation device and plant cultivation method - Google Patents

Abstract

To provide a plant cultivation device that can suppress rise in temperature of liquid fertilizer and lack of oxygen on a root surface.SOLUTION: A plant cultivation device comprises: a plant holding part 5 which holds a plant 6 and is capable of leading roots extending from the plant 6 to outside; a cultivation tank 2 on which the plant holding part 5 is mounted, which is capable of storing liquid fertilizer, and has a bottom surface 2a receiving roots extending from the plant 6 and has a sidewall 2b surrounding the plant holding part 5; a plurality of drain holes 13 which are formed in the cultivation tank 2 and adjust a water level of liquid fertilizer by draining at least a part of the liquid fertilizer; a reservoir tank 7 which is capable of storing at least a part of liquid fertilizer drained from the plurality of the drain holes 13; a pump 17 which circulates liquid fertilizer by supplying at least a part thereof stored in the reservoir tank 7 to the cultivation tank 2; and a pump control part 19 which performs control of intermittent operation of the pump 17, in which the pump control part 17 adjusts ratio of down time with respect to circulation time of the pump 17 corresponding to the growth of the plant 6.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a plant cultivation apparatus and a plant cultivation method.

  There is a hydroponic plant cultivation apparatus that cultivates plants by immersing the roots of the plants in liquid fertilizer. In such a plant cultivation apparatus, artificial light for photosynthesis is irradiated to a plant to be cultivated, and liquid fertilizer containing nutrients necessary for plant growth is supplied around the root of the plant (for example, Patent Document 1). reference). In patent document 1, while immersing the porous container which planted the plant in the liquid fertilizer in a cultivation tank, the liquid fertilizer discharged | emitted via the discharge port from the cultivation tank is stored in a storage tank, and the liquid fertilizer in a storage tank is supplied to a supply port. A method of supplying to the cultivation tank via the slab has been proposed.

JP 62-029924 A

  However, in Patent Document 1, a part of the heat generated by the pump used to supply the liquid fertilizer in the storage tank to the cultivation tank is transmitted to the cultivation tank together with the liquid fertilizer, and the temperature of the liquid fertilizer in the cultivation tank (hereinafter also referred to as water temperature). ) Will rise. If the water temperature of the liquid fertilizer in the cultivation tank rises, not only will the dissolved oxygen in the liquid fertilizer decrease, but the respiration of the plants housed in the cultivation tank will be promoted, and there is a concern about oxygen shortage on the root surface. In addition, the photosynthetic efficiency decreases due to the increased respiration of plants.

  This indication is made in view of the above-mentioned situation, and aims at providing the plant cultivation apparatus and plant cultivation method which can control the temperature rise of liquid manure, and the oxygen deficiency in the root surface.

  In order to solve the above problems, a plant cultivation apparatus according to an embodiment of the present disclosure is a plant cultivation apparatus that cultivates a plant by immersing the root of the plant in liquid fertilizer, and holds the plant, and from the plant A plant holding part capable of passing the extended root to the outside, a bottom surface for receiving the root extended from the plant and a plant which is placed in the cultivation tank on which the plant holding part is placed and can store the liquid fertilizer A cultivation tank having a side wall that surrounds the holding portion, a plurality of drain holes that are formed in the cultivation tank and adjust the water level of the liquid fertilizer by draining at least a part of the liquid fertilizer, and drained from the drain holes. A storage tank capable of storing at least a part of the tank, a pump for circulating the liquid manure by supplying the at least part of the storage tank stored in the storage tank, and a control for intermittently operating the pump. The A pump control unit, wherein the pump control unit has a ratio of an interruption time that is a time for interrupting the operation of the pump to a circulation time that is a time for performing the operation of the pump according to the growth of the plant. adjust.

  These general or some specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM. You may implement | achieve with arbitrary combinations of a circuit, a computer program, and a recording medium.

  According to the plant cultivation apparatus and the like of the present disclosure, it is possible to suppress an increase in the temperature of liquid fertilizer and oxygen shortage on the root surface.

It is a schematic diagram which shows the external appearance of the plant cultivation apparatus in Embodiment 1. FIG. It is a cross-sectional schematic diagram which shows an example of a structure of the plant cultivation apparatus in Embodiment 1. FIG. It is a plane schematic diagram of the plant cultivation apparatus in Embodiment 1. 5 is a diagram illustrating an example of intermittent operation in Embodiment 1. [FIG. 3 is a flowchart showing an example of the operation of the plant cultivation apparatus in the first embodiment. 3 is a flowchart illustrating an example of intermittent operation control of the plant cultivation apparatus according to Embodiment 1. It is explanatory drawing of the water level of the liquid fertilizer of the plant cultivation apparatus in the circulation time of Embodiment 1. FIG. It is explanatory drawing of the water level of the liquid fertilizer of the plant cultivation apparatus in the interruption time of Embodiment 1. FIG. It is a figure which shows an example of the relationship between the growth state of the root of the plant in the cultivation tank of Embodiment 1, and the water level of liquid fertilizer. It is a schematic diagram which shows the external appearance of the plant cultivation apparatus in Embodiment 2. It is a cross-sectional schematic diagram which shows an example of a structure of the plant cultivation apparatus in Embodiment 2. FIG. It is a plane schematic diagram of the plant cultivation apparatus in Embodiment 2. It is explanatory drawing of the relationship between the water level of the liquid fertilizer of the cultivation tank in Embodiment 2, and the growth of the root of a plant. It is explanatory drawing of the relationship between the water level of the liquid fertilizer of the cultivation tank in Embodiment 2, and the growth of the root of a plant. It is explanatory drawing of the relationship between the water level of the liquid fertilizer of the cultivation tank in Embodiment 2, and the growth of the root of a plant. It is an upper surface schematic diagram of the cultivation tank which shows the fluid state of the liquid manure in Embodiment 2. FIG. It is a plane schematic diagram of the plant cultivation apparatus in Embodiment 3.

  Each of the embodiments described below shows a specific example of the present disclosure. Numerical values, shapes, components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present disclosure. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements. In all the embodiments, the contents can be combined.

(Embodiment 1)
Below, the plant cultivation apparatus 1 in Embodiment 1 is demonstrated, referring drawings.

[Configuration of plant cultivation apparatus 1]
FIG. 1 is a schematic diagram showing an appearance of a plant cultivation apparatus 1 according to the first embodiment. FIG. 2 is a schematic cross-sectional view illustrating an example of the configuration of the plant cultivation apparatus 1 according to the first embodiment. FIG. 3 is a schematic plan view of the plant cultivation device 1 according to the first embodiment. The cross-sectional schematic diagram shown in FIG. 2 corresponds to the X1-X2 cross section in FIG. The plan view shown in FIG. 3 corresponds to a view when the cover 12 of the plant cultivation apparatus 1 in FIG.

  The plant cultivation device 1 is a hydroponic plant cultivation device that cultivates the plant 6 by immersing the root of the plant 6 in liquid fertilizer. Here, the plant 6 to be cultivated is a vegetable such as a tomato or a foliage plant, but is not limited thereto and may be any plant that can be cultivated by a hydroponic method. Moreover, liquid fertilizer is a liquid fertilizer and contains nutrients for cultivation in water.

  As shown in FIGS. 1 and 2, the plant cultivation apparatus 1 includes a plant holding unit 5, a cultivation tank 2 having a plurality of drain holes 13, a storage tank 7, a pump 17, and a pump control unit 19. .

[Plant holding part 5]
The plant holding unit 5 is a planting pot that holds the plant 6 and can pass the roots extended from the plant 6 to the outside. In the present embodiment, the plant holding unit 5 is planted with a plant 6 that is a hydroponic vegetable such as a tomato. More specifically, the plant holding unit 5 stores a sponge or the like serving as a medium, and holds the root of the plant 6 to be cultivated, so that the plant 6 is planted. The bottom part and the side part of the plant holding part 5 are opened. The plant holding unit 5 is placed in the cultivation tank 2 via the pot placement unit 4, and in accordance with the growth of the plant 6, the prosperous root extending from the root part of the plant 6 is grown through the opening. 2 can communicate.

[Cultivation tank 2]
The cultivation tank 2 is a tank on which the plant holding unit 5 is placed and can store liquid fertilizer. The cultivation tank 2 has a plurality of drain holes for adjusting the water level of liquid fertilizer. The cultivation tank 2 has a bottom surface 2 a that receives roots extending from the plant 6 and a side wall 2 b that surrounds the plant holding unit 5. Here, the distance from the plant holding part 5 to the side wall 2b may be a distance that can be reached by a root extending from the plant 6. Moreover, the cultivation tank 2 may have a root-proof permeable sheet 18 that prevents the roots of the plant 6 from entering the plurality of drain holes 13.

  In this Embodiment, as shown in FIG.2 and FIG.3, for example, the cultivation tank 2 is a box-shaped container having a concave cross section in which side walls 2b are erected on four sides of a substantially rectangular bottom surface 2a, and liquid fertilizer is provided. Can be stored. The lower end of the cultivation tank 2 is held in the storage tank 7 by a holding member (not shown).

  Moreover, the some drainage hole 13 is provided in the side wall 2b of the cultivation tank 2, and the pot mounting part 4 is provided in the center part of the bottom face 2a. The cultivation tank 2 adjusts the water level of the liquid fertilizer with a plurality of drain holes 13 and places the plant holding part 5 via the pot placement part 4. As shown in FIG. 1, the cultivation tank 2 further includes a water supply pipe 14, a water level limiting drain 15, and a root-proof permeable sheet 18.

<Pot placement part 4>
The pot mounting part 4 is provided in the center part of the cultivation tank 2, as shown in FIG. In other words, the pot placement unit 4 is provided at a position surrounded by the side walls 2b on the four sides of the cultivation tank 2, and the plant holding unit 5 is placed thereon. The height of the pot mounting part 4 is such that the bottom part of the placed plant holding part 5 is immersed in liquid manure, and the stem part of the plant 6 planted in the plant holding part 5 is from the upper end of the cultivation tank 2. Is also provided to extend upward.

<Multiple drain holes 13>
The some drainage hole 13 is formed in the cultivation tank 2, and adjusts the water level of the said liquid manure by draining at least one part of the liquid manure.

  In the present embodiment, the plurality of drain holes 13 are formed at a predetermined pitch in the horizontal direction. That is, as shown in FIGS. 1 to 3, the plurality of drain holes 13 are provided at a predetermined pitch at substantially the same height from the bottom surface 2 a in the lower part of the side wall 2 b of the cultivation tank 2. The plurality of drain holes 13 can discharge most of the liquid fertilizer in the cultivation tank 2 and expose all the roots of the plant 6, regardless of the state of the plant 6, and the bottom surface 2 a of the cultivation tank 2. It is provided at a low height position. In addition, the some drainage hole 13 may be provided in the bottom face 2a of the cultivation tank 2, and may be provided in the bottom face 2a and the side wall 2b of the cultivation tank 2. Moreover, the several drainage hole 13 may be formed in the predetermined pitch from the bottom face 2a of the cultivation tank 2 to the predetermined multi-step height.

  Thus, the plurality of drain holes 13 can discharge most of the liquid fertilizer in the cultivation tank 2 and expose all the roots of the plant 6 during the interruption time in which the operation of the pump 17 described later is interrupted. Further, in the plurality of drain holes 13, the discharge of the liquid fertilizer in the cultivation tank 2 and the supply of the liquid fertilizer to the cultivation tank 2 by the pump 17 may be made the same during the circulation time when the pump 17 described later operates. it can.

<Water supply pipe 14>
The water supply pipe 14 is disposed so as to be located in the upper part inside the cultivation tank 2. In the example shown in FIGS. 1 to 3, the tip of the water supply pipe 14 is located in the vicinity of the plant holding unit 5. The water supply pipe 14 is connected to a connection pipe 16 provided outside the cultivation tank 2. The water supply pipe 14 supplies the liquid fertilizer supplied from the storage tank 7 via the connection pipe 16 to the cultivation tank 2 when the pump 17 is operated.

  1 to 3, the tip of the water supply pipe 14 is provided so as to be located in the vicinity of the plant holding unit 5, but is not limited thereto, and is provided so as to be located in the vicinity of the side wall 2 b. May be. The aspect of the water supply pipe 14 is not limited as long as the liquid fertilizer fed from the storage tank 7 via the connection pipe 16 can be supplied to the cultivation tank 2 when the pump 17 is operated.

<Water level limiting drain 15>
The water level limiting drain 15 is erected at one corner of the bottom surface 2 a of the cultivation tank 2. In this Embodiment, as shown in FIG.1 and FIG.3, the drain port 15 for water level restrictions is standingly arranged in the lower left corner part of the bottom face 2a of the cultivation tank 2 in planar view. Further, the water level limiting drain 15 is a hollow tube member and has an inner hole provided for drainage, which is an inner hole that penetrates the bottom surface 2 a and communicates with the inside of the storage tank 7. The height of the water level limiting drain 15 is provided in accordance with a predetermined level of liquid fertilizer in the cultivation tank 2.

  As a result, the water level restriction drain port 15 is larger in the amount of liquid fertilizer supplied into the cultivation tank 2 than the amount of drainage discharged through the plurality of drain holes 13, and the water level in the cultivation tank 2 is increased. When the limit water level is exceeded, excess liquid fertilizer can be discharged into the storage tank 7 through the inner hole.

  In addition, if the water level restriction drain 15 is erected at the corner of the bottom surface 2a of the cultivation tank 2, it is erected not only at the lower left corner but also at the upper left corner, upper right corner, and lower right corner. It may be.

<Root-proof permeable sheet 18>
The root-proof permeable sheet 18 is an example of a root-preventing tool that prevents the roots of the plant 6 from entering the plurality of drain holes 13.

  In the present embodiment, the root-proof permeable sheet 18 is laid on the bottom surface 2 a of the cultivation tank 2 and the inner surfaces of the side walls 2 b so as to cover the plurality of drain holes 13. The root-proof water-permeable sheet 18 is, for example, a sheet-like member having water permeability provided with a predetermined mesh opening, and suppresses the passage of the roots of the plant 6 while allowing the liquid fertilizer to pass therethrough. That is, the root-proof water-permeable sheet 18 is laid on the inner surface of the cultivation tank 2, thereby preventing the root of the plant 6 from entering the drain holes 13 without hindering the functions as the plurality of drain holes 13.

[Storage tank 7]
The storage tank 7 is a tank capable of storing at least a part of the liquid fertilizer drained from the plurality of drain holes 13 of the cultivation tank 2. The storage tank 7 is arrange | positioned under the cultivation tank 2, and arrange | positions the at least lower end part of the cultivation tank 2 inside.

  In this Embodiment, the storage tank 7 is arrange | positioned under the cultivation tank 2, and can accumulate the liquid fertilizer drained from the cultivation tank 2 with the liquid fertilizer prepared previously. More specifically, the storage tank 7 is a rectangular parallelepiped box-shaped container, and has a rectangular bottom portion 7a and side walls 7b erected on four sides of the bottom portion 7a. The storage tank 7 holds at least the lower end portion of the cultivation tank 2 inside by a holding member (not shown), and secures a space for storing liquid manure between the bottom 7 a and the bottom surface 2 a of the cultivation tank 2.

  Thus, the storage tank 7 can make the whole height of the plant cultivation apparatus 1 low by setting it as the structure which overlaps a part of cultivation tank 2. FIG. Thereby, it becomes possible to arrange | position the several plant cultivation apparatus 1 in multiple steps using a shelf etc., and can realize the plant cultivation apparatus 1 excellent in area productivity.

  The storage tank 7 preferably further has a cover 12.

<Cover 12>
The cover 12 removably covers the storage tank 7 and can be enclosed by one bottom 7a and four side walls 7b of the storage tank 7. Thereby, not only can the root area of the plant 6 in the cultivation tank 2 be kept at a constant humidity such as a humidity of 100%, but also the root of the plant 6 and the liquid fertilizer can be prevented from being exposed to light. By preventing the liquid fertilizer from being exposed to light, it is possible to prevent the occurrence of unintended things in the liquid fertilizer, such as the occurrence of blue sea bream.

  Further, the cover 12 is provided with an opening 12 a at a position corresponding to the mounting position of the plant holding unit 5.

  The opening 12 a provided in this way can extend the stem of the plant 6 planted in the plant holding unit 5 placed in the cultivation tank 2 upward. Therefore, the size of the opening 12 a is larger than the stem portion of the plant 6 and smaller than the diameter of the plant holding portion 5. The size of the opening 12a is preferably as small as possible so that light does not enter the root region of the plant 6 from the opening 12a.

  Further, the cover 12 can be removed when the growth of the plant 6 is not progressing, but can not be removed when the growth of the plant 6 is advanced, but can be shifted. In addition, the cover 12 may be formed so that it can be divided into two at the center, and can be removed even when the plant 6 grows. By removing or shifting the cover 12, it is possible to check the supply state of liquid fertilizer in the cultivation tank 2, the state of drainage, and the state of the root of the plant 6. Moreover, by removing the cover 12 when necessary, operations such as cleaning the inside of the storage tank 7 and the cultivation tank 2 can be performed efficiently.

  The cover 12 and the storage tank 7 each form a heat insulating structure. This is independent of changes in ambient temperature.

[Pump 17]
The pump 17 is intermittently operated by the pump control unit 19. The pump control unit 19 adjusts the ratio of the interruption time, which is the time for interrupting the operation of the pump 17 to the circulation time, which is the time for the pump 17 to operate, according to the growth of the plant 6. During operation, the pump 17 circulates the liquid manure by supplying at least a part of the liquid manure stored in the storage tank to the cultivation tank 2.

  In the present embodiment, the pump 17 is disposed on the upper surface of the bottom 7 a of the storage tank 7 and is connected to the connecting pipe 16. In addition, a timer set by the pump control unit 19 is connected to the power source of the pump 17. In operation, the pump 17 feeds the liquid fertilizer stored in the storage tank 7 to the connecting pipe 16. Thus, the pump 17 can supply liquid manure to the cultivation tank 2 from the water supply pipe 14 connected to the connection pipe 16 and circulate the liquid manure during operation. On the other hand, the pump 17 does not feed the liquid fertilizer stored in the storage tank 7 to the connecting pipe 16 when the operation is stopped. That is, the state in which the liquid fertilizer in the cultivation tank 2 is discharged from the drain hole 13 to the storage tank 7 is maintained, and the level of the liquid fertilizer in the cultivation tank 2 can be lowered.

[Pump control unit 19]
FIG. 4 is a diagram illustrating an example of the intermittent operation in the first embodiment.

  The pump control unit 19 performs control to cause the pump 17 to operate intermittently. The pump control unit 19 adjusts the ratio of the interruption time to the circulation time in the pump 17 according to the growth of the plant 6. Here, the interruption time should just be more than the time adjusted by the some drainage hole 13 of the cultivation tank 2 to the water level of the liquid manure which the whole root of the plant 6 exposes. The pump control unit 19 may perform control to intermittently operate the pump 17 so that the ratio of the interruption time to the circulation time increases as the root growth of the plant 6 progresses. In addition, the pump control unit 19 performs control to intermittently operate the pump 17 by increasing the ratio of the interruption time to the circulation time in the direction after the flower of the plant 6 blooms than before the flower of the plant 6 blooms. Also good.

  In the present embodiment, the pump control unit 19 is realized by a computer having a memory or the like, and controls on / off of the power supply of the pump 17 by a timer (not shown) connected to the power supply of the pump 17. Control to operate intermittently. The pump controller 19 may be a timer itself connected to the power source of the pump 17. The pump control unit 19 sets the interruption time to a time that is adjusted to the liquid level of the liquid manure where all the roots of the plant 6 are exposed by the plurality of drain holes 13 of the cultivation tank 2, and according to the growth of the plant 6. Adjust the ratio of interruption time to circulation time.

  For example, as shown in FIG. 4, the pump control unit 19 sets a timer connected to the power source of the pump 17 so that the circulation time is 10 minutes and the interruption time is 10 minutes before the flower of the plant 6 blooms. Set. On the other hand, after the flower of the plant 6 blooms, the pump control unit 19 sets a timer connected to the power source of the pump 17 so that the circulation time is 3 minutes and the interruption time is 12 minutes. In this way, the pump control unit 19 performs control to intermittently operate the pump 17 by increasing the ratio of the interruption time to the circulation time in the direction after the flower of the plant 6 blooms than before the flower of the plant 6 blooms. Do. The pump control unit 19 may perform control to intermittently operate the pump 17 so that the ratio of the interruption time to the circulation time increases as the root growth of the plant 6 progresses.

  As mentioned above, the temperature rise of liquid manure can be suppressed by adjusting the said ratio according to the growth of the plant 6. FIG. This is because, during the circulation time, while the liquid fertilizer is circulating, the temperature of the circulating liquid fertilizer gradually rises due to the heat generated by the pump 17, whereas during the interruption time, the temperature of the liquid fertilizer decreases because there is no heat source. That is, even when part of the heat generated by the pump 17 is transmitted to the cultivation tank 2 together with the liquid fertilizer and the temperature of the liquid fertilizer in the cultivation tank 2 rises, the operation of the pump 17 is stopped until the temperature of the liquid fertilizer returns to the original temperature. Thus, the pump can be operated again after the original temperature is reached.

  And if the rise in the temperature of liquid fertilizer can be suppressed, since the respiration of the plant 6 can be suppressed, it can be connected to the elimination of oxygen deficiency and the improvement of the photosynthetic efficiency of the plant 6 which is a root growth system.

  Furthermore, adjusting the ratio according to the growth of the plant 6 also means adjusting the stress on the plant 6, and considering the balance between the reproductive growth of the plant 6 and the vegetative growth, the liquid fertilizer is applied at an appropriate temperature. It can be circulated. This is because the temperature of the liquid fertilizer is stabilized if the circulation time is set sufficiently short and the interruption time is set sufficiently long with respect to the temperature change of the liquid fertilizer (heat capacity of the liquid fertilizer). That is, by appropriately setting the circulation time and the interruption time, an increase in the average temperature of the liquid fertilizer by the pump 17 can be suppressed according to the growth stage of the plant 6. Thereby, not only can the decrease of dissolved oxygen in the liquid fertilizer of the cultivation tank 2 be suppressed, but also the respiration of the plants accommodated in the cultivation tank 2 is suppressed, so that the oxygen shortage is eliminated and the photosynthesis efficiency can be improved. .

  Moreover, the pump control part 19 sets interruption time more than the time adjusted by the some drainage hole 13 of the cultivation tank 2 to the water level of the liquid manure which all the roots of the plant 6 expose. Thereby, the liquid level of liquid fertilizer falls to the height with the some drainage hole 13 in the cultivation tank 2, and the whole root of the plant 6 can be exposed in interruption time.

  As a result, liquid fertilizer in the root area of dense plant 6 with poor fluidity can be forcibly drained, so that not only the root surface is exposed to air, but also nutrient balance is taken during recirculation and liquid fertilizer with high dissolved oxygen concentration is poured. Can do. Therefore, the liquid fertilizer with balanced nutrients can be brought into uniform contact with the entire root and variation in the growth state can be suppressed.

  Further, the pump control unit 19 may set the interruption time before the time when the root of the plant 6 is withered more than the above time.

  Thereby, since the whole root of the plant 6 is exposed during the interruption time and water absorption can be suppressed for the plant 6 by maintaining the state, the plant 6 that is a hydroponic vegetable such as tomato is used. The actual sugar content can be improved.

  In addition, the growth stage of the plant 6 may be confirmed visually by the manager or the user of the cultivation tank 2, and the root of the plant 6 planted in the plant holding unit 5 is photographed by a photographing means such as a camera. You may confirm it. Of course, it is also possible to automatically analyze an image photographed by a photographing means such as a camera and feed back the result of determining the growth stage of the plant 6 to the pump control unit 19. In this case, the pump control unit 19 may change the setting of the timer connected to the power source of the pump 17, that is, the circulation time and the interruption time, based on the feedback. Moreover, you may determine the growth stage of the plant 6 using the float sensor floated on the liquid fertilizer of the cultivation tank 2. FIG.

[Operation of plant cultivation apparatus 1]
Next, operation | movement of the plant cultivation apparatus 1 in Embodiment 1 mentioned above is demonstrated.

  FIG. 5A is a flowchart illustrating an example of the operation of the plant cultivation apparatus 1 according to Embodiment 1. FIG. 5B is a flowchart illustrating an example of intermittent operation control of the plant cultivation apparatus 1 according to Embodiment 1. In FIG. 5B, elements similar to those in FIG. 5A are denoted by the same reference numerals. FIG. 6 is an explanatory diagram of the water level of the liquid fertilizer of the plant cultivation apparatus 1 during the circulation time according to the first embodiment. FIG. 7 is an explanatory diagram of the water level of liquid fertilizer in the plant cultivation device 1 during the interruption time of the first embodiment. 6 and 7, the same elements as those in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown to FIG. 5A, in the plant cultivation apparatus 1, the water level of liquid manure is adjusted by draining at least one part of liquid manure to the storage tank 7 to the several drainage hole 13 formed in the cultivation tank 2 (S12). . More specifically, the administrator or robot of the plant cultivation apparatus 1 first pours liquid fertilizer into the cultivation tank 2 to accumulate the liquid fertilizer, and then stores at least a part of the liquid fertilizer in the plurality of drain holes 13. The water level of liquid fertilizer is adjusted by draining into the tank 7.

  Next, the ratio of the interruption time to the circulation time is adjusted according to the growth of the plant 6 (S13). More specifically, the administrator or the robot of the plant cultivation apparatus 1 sets the circulation time and interruption time according to the growth stage of the plant 6 held in the plant holding unit 5 and the timer connected to the power source of the pump 17. Thus, the ratio of the interruption time to the circulation time is adjusted. And control of the intermittent operation | movement which operates or interrupts the pump 17 is started.

  Here, when the intermittent operation of the pump 17 is an operation, that is, a circulation time (circulation time in S14), the liquid fertilizer is supplied to the cultivation tank 2 by causing the pump 17 to supply a part of the liquid manure stored in the storage tank 7. Circulate (S15). More specifically, in the plant cultivation device 1 of the circulation time, for example, as shown in FIG. 6, the discharge of the liquid fertilizer 21 in the cultivation tank 2 and the supply of the liquid fertilizer 22 in the storage tank 7 to the cultivation tank 2 by the pump 17 The liquid fertilizer 21 is circulated while the water level of the liquid fertilizer 21 is kept constant.

  On the other hand, when the intermittent operation of the pump 17 is interrupted (stopped), that is, the interrupt time (interruption time in S14), the process proceeds to S12, and the liquid fertilizer 21 is drained into the plurality of drain holes 13 of the cultivation tank 2, thereby causing the liquid fertilizer water level To adjust. More specifically, in the plant cultivation apparatus 1 at the interruption time, for example, as shown in FIG. 7, only the liquid fertilizer 21 is discharged from the cultivation tank 2, and the liquid level of the liquid fertilizer 21 is lowered, for example, all discharged. All the roots of the plant 6 are exposed.

  Here, an example of intermittent operation control, that is, an example of detailed operations in S13 and S14, will be described with reference to FIG. 5B.

  In S13, the administrator or robot of the plant cultivation apparatus 1 confirms the growth of the plant 6 held in the plant holding unit 5 (S131), and the ratio of the interruption time to the circulation time (that is, the circulation time / interruption time) It is confirmed whether the setting is appropriate (S132).

  If the setting is appropriate in S132 (YES in S132), the process proceeds to S134 described later. On the other hand, if the setting is not appropriate (YES in S132), the circulation time and the interruption time are set according to the growth of the plant 6 held in the plant holding unit 5 (S133).

  Next, the administrator or robot of the plant cultivation apparatus 1 turns on the power switch of the pump 17 (described as pump output SW in the figure) (S134). In addition, since the switch of the power supply of the pump 17 is always ON during cultivation, S134 becomes control which performs only cultivation start.

  Next, in S14, if the circulation time set in the timer connected to the power source of the pump 17 has not elapsed (NO in S141), the pump 17 continues to operate (S142). Thereby, in the plant cultivation apparatus 1, liquid fertilizer is pumped from the storage tank 7 and supplied to the cultivation tank 2, while being drained from the plurality of drain holes 13 to the storage tank 7. At this time, the water level of the cultivation tank 2 rises until the supply speed = drainage speed.

  On the other hand, if the circulation time set in the timer connected to the power source of the pump 17 has elapsed in S14 (YES in S141), the process proceeds to S143.

  In S143, if the interruption time set in the timer connected to the power source of the pump 17 has not elapsed (NO in S143), the pump 17 interrupts or stops the operation (S144). Thereby, in the plant cultivation apparatus 1, while pumping up the liquid manure from the storage tank 7 to the cultivation tank 2 is stopped, draining from the plurality of drain holes 13 to the storage tank 7 is continued. As a result, the water level of the cultivation tank 2 falls to the vicinity of the plurality of drain holes 13, and the entire root of the plant 6 is exposed from the water surface.

  On the other hand, if the interruption time set in the timer connected to the power source of the pump 17 has elapsed in S143 (NO in S141), the process proceeds to S141.

  Thus, in the plant cultivation apparatus 1, the intermittent operation of the pump 17 is controlled.

[Effects]
As mentioned above, according to Embodiment 1, the plant cultivation apparatus 1 which can suppress the temperature rise of liquid fertilizer and the oxygen shortage in a root surface is realizable by operating the pump which circulates liquid fertilizer intermittently.

  More specifically, the plant cultivation apparatus 1 in the present embodiment is a plant cultivation apparatus that cultivates the plant 6 by immersing the root of the plant 6 in the liquid fertilizer 21, holds the plant 6, and A plant holding part 5 capable of passing the extended root to the outside, and a bottom surface 2a for receiving the root extended from the plant 6 in which the plant holding part 5 is placed and the cultivation tank 2 is capable of storing the liquid fertilizer 21. And a cultivation tank 2 having a side wall 2b surrounding the plant holding part 5, and a plurality of drain holes 13 formed in the cultivation tank 2 to adjust the water level of the liquid fertilizer 21 by draining at least a part of the liquid fertilizer 21; The storage tank 7 capable of storing the at least a part (liquid fertilizer 22) drained from the plurality of drain holes 13 and supplying the at least a part stored in the storage tank 7 to the cultivation tank 2 A pump 17 for circulating 21 and a pump Comprises 17 pump control unit 19 performs control to intermittently operate the, the. And the pump control part 19 adjusts the ratio of the interruption time which is the time which interrupts the operation | movement of the pump 17 with respect to the circulation time which is the time which operates the pump 17, according to the growth of the plant 6. FIG.

  According to this configuration, even when part of the heat generated by the pump 17 is transmitted to the cultivation tank 2 together with the liquid fertilizer 22 and the temperature of the liquid fertilizer 21 in the cultivation tank 2 rises, the temperature of the liquid fertilizer 21 returns to the original temperature. The operation of the pump 17 can be stopped and the operation of the pump can be performed again after reaching the original temperature. That is, the temperature rise of the liquid manure 21 can be suppressed by intermittently operating the pump 17 that circulates the liquid manure 21. In the circulation time, while the liquid fertilizer 21 is circulating, the temperature of the circulating liquid fertilizers 21 and 22 gradually increases due to the heat generated by the pump 17, while in the interruption time, the temperature of the liquid fertilizers 21 and 22 decreases because there is no heat source. Because.

  And since the raise of the temperature of the liquid fertilizer 21 can be suppressed, a dissolved acidity density | concentration does not fall and the respiration rate in the root of the plant 6 can also be optimized, It can lead to improvement of photosynthesis efficiency. Moreover, the stress to the root by intermittent circulation makes the growth balance of the plant 6 reproductive growth> vegetative growth. Thereby, it can lead to the improvement of the quality and yield of a fruit, and the cultivation period extension in a limited area.

  Furthermore, according to the growth stage of the plant 6, by appropriately setting the circulation time or the interruption time of the interruption time with respect to the circulation time or both, that is, the circulation time and the interruption time according to the growth of the plant 6, An increase in the average temperature of the liquid fertilizers 21 and 22 by the pump 17 can be suppressed.

  Adjusting the ratio also means adjusting the stress on the plant 6, and the liquid fertilizer 21 can be circulated at an appropriate temperature while considering the balance between the reproductive growth of the plant 6 and vegetative growth. This is because the temperature of the liquid manures 21 and 22 is stabilized if the circulation time is set sufficiently short and the interruption time is set sufficiently long with respect to the temperature change of the liquid manures 21 and 22 (heat capacity of the liquid manures 21 and 22).

  Thereby, not only can the decrease in the dissolved oxygen concentration due to the temperature rise of the liquid fertilizers 21 and 22 be suppressed, but the root respiration will not increase, and the photosynthetic efficiency can be improved.

  Here, for example, the interruption time is equal to or longer than the time when the plurality of drain holes 13 adjust the water level of the liquid fertilizer 21 at which all the roots of the plant 6 are exposed.

  Thereby, most of the liquid fertilizer 21 in the cultivation tank during the interruption time can be discharged, and all the roots of the plant 6 can be exposed. That is, the liquid fertilizer 21 in the root area of the plant 6 whose fluidity is poor and the nutrient balance is lost and the dissolved oxygen concentration is reduced is forcibly drained, and the surface of the whole root is exposed to the air. Can breathe at a concentration. And the liquid fertilizer 22 which melt | dissolved uniformly without reducing the concentration of dissolved oxygen at the time of recirculation, and was able to maintain the nutrient balance can be poured as the liquid fertilizer 21. Thereby, the liquid fertilizer 21 with high dissolved oxygen concentration and well-balanced nutrients can be uniformly contacted with the whole root uniformly, and the growth failure of the plant 6 due to oxygen deficiency and nutrient deficiency can be suppressed.

  Here, it demonstrates as an example that the liquid fertilizer 21 with high dissolved oxygen concentration and well-balanced nutrients can be uniformly and uniformly contacted with the whole root. FIG. 8 is a diagram illustrating an example of a relationship between the root growth state of the plant 6 and the liquid level of liquid fertilizer in the cultivation tank 2 of the first embodiment.

  For example, as shown in FIG. 8, it is assumed that the root 6 a grows with the growth of the plant 6, reaches a position exceeding the height of the plurality of drain holes 13, and closes the plurality of drain holes 13. In this case, depending on the root region of the plant 6, the fluidity of the liquid fertilizer 21 is poor and the nutrient balance of the liquid fertilizer 21 is lost, or the dissolved oxygen concentration of the liquid fertilizer 21 is decreased. In hydroponics, nutrients and oxygen necessary for plant growth need to be supplied to the root 6a through the liquid fertilizer 21, so that the root 6a grows and grows as the plant 6 grows. It is necessary to bring the liquid fertilizer 21 into contact with each part as uniformly as possible. However, in this state as shown in FIG. 8, it is difficult to induce the flow of the liquid fertilizer 21, and it is difficult to make the liquid fertilizer 21 contact the entire root of the plant 6 evenly, and the supply of nutrients and oxygen to the root 6a of the plant 6 is uniform. Not done. As a result, oxygen deficiency and nutrient deficiency in the root 6a can cause plant 6 disease and root rot.

  On the other hand, in the plant cultivation apparatus 1 according to the first embodiment, for example, as described with reference to FIG. 7, only the discharge of the liquid fertilizer 21 in the cultivation tank 2 is performed during the interruption time, and the water level of the liquid fertilizer 21 is lowered. All the roots 6a of the plant 6 can be exposed, for example, by discharging the whole. Thereby, the surface of the whole root 6a can be exposed to air. Moreover, at the time of subsequent recirculation (circulation time), in the plant cultivation apparatus 1, as demonstrated, for example in FIG. 6, in the cultivation tank 2, oxygen concentration melt | dissolved uniformly and the nutrient balance was taken. Liquid fertilizer 21 is poured and circulated. Therefore, nutrients and oxygen can be uniformly supplied to the entire root 6a of the plant 6.

  Further, for example, the pump control unit 19 may perform control to perform intermittent operation so that the ratio of the interruption time to the circulation time increases as the root growth of the plant 6 progresses.

  Thus, adjusting the ratio according to the growth of the plant 6 is also adjusting the stress on the plant 6, and considering the balance between the reproductive growth and the vegetative growth of the plant 6 at an appropriate temperature. The liquid fertilizer 21 can be circulated. Therefore, not only can the decrease in the dissolved oxygen concentration of the liquid fertilizer 21 in the cultivation tank 2 be suppressed, but sufficient oxygen can be supplied to the entire root accommodated in the cultivation tank 2. Moreover, according to the growth of the plant 6, a root respiration rate can be optimized and photosynthesis efficiency can be improved.

  In addition, for example, the pump control unit 19 may perform an intermittent operation in which the ratio of the interruption time to the circulation time is increased after the flower of the plant 6 is bloomed than before the flower of the plant 6 is bloomed. .

  Thus, adjusting the ratio according to the growth of the plant 6 is also adjusting the stress on the plant 6, and considering the balance between the reproductive growth and the vegetative growth of the plant 6 at an appropriate temperature. The liquid fertilizer 21 can be circulated. Therefore, not only can the decrease in the dissolved oxygen concentration of the liquid fertilizer 21 in the cultivation tank 2 be suppressed, but sufficient oxygen can be supplied to the entire root accommodated in the cultivation tank 2. Moreover, according to the growth of the plant 6, a root respiration rate can be optimized and photosynthesis efficiency can be improved.

  Further, for example, the cultivation tank 2 may further include a root-proof permeable sheet 18 that prevents the roots of the plant 6 from entering the plurality of drain holes 13.

  Thereby, the approach of the root of the plant 6 into the drainage hole 13 can be prevented without inhibiting the function as the plurality of drainage holes 13.

  Further, for example, the storage tank 7 may be disposed below the cultivation tank 2 and at least the lower end portion of the cultivation tank 2 may be disposed inside.

  Thus, the storage tank 7 can make the whole height of the plant cultivation apparatus 1 low by setting it as the structure which overlaps a part of cultivation tank 2. FIG. Thereby, it becomes possible to arrange | position the several plant cultivation apparatus 1 in multiple steps using a shelf etc., and can realize the plant cultivation apparatus 1 excellent in area productivity.

  Further, for example, the distance from the plant holding unit 5 to the side wall 2b may be a distance that can be reached by the roots extending from the plant 6.

(Embodiment 2)
Next, the plant cultivation apparatus 1A in Embodiment 2 will be described. Hereinafter, a description will be given focusing on differences from the first embodiment.

[Configuration of plant cultivation apparatus 1A]
FIG. 9 is a schematic diagram illustrating an appearance of the plant cultivation apparatus according to the second embodiment. FIG. 10 is a schematic cross-sectional view showing an example of the configuration of the plant cultivation apparatus 1A in the second embodiment. FIG. 11 is a schematic plan view of the plant cultivation apparatus 1A in the second embodiment. In addition, the same code | symbol is attached | subjected to the element similar to FIGS. 1-3. The cross-sectional schematic diagram shown in FIG. 10 corresponds to the X3-X4 cross section in FIG. The plan view shown in FIG. 11 corresponds to the view when viewed from above with the cover 12A of the plant cultivation apparatus 1A in FIG. 10 and 11, the first direction is a direction in which a later-described water supply pipe 14 </ b> A is extended, and a direction orthogonal to the first direction is defined as a second direction.

  Similar to the plant cultivation device 1, the plant cultivation device 1 </ b> A is a hydroponic plant cultivation device that cultivates the plant 6 by immersing the roots of the plant 6 in liquid fertilizer. As shown in FIGS. 9 and 10, the plant cultivation apparatus 1 </ b> A includes a plant holding unit 5, a cultivation tank 2 having a plurality of drain holes 13, a storage tank 7, a pump 17 </ b> A, and a pump control unit 19. .

  Compared with the plant cultivation apparatus 1 of Embodiment 1, the plant cultivation apparatus 1A is a part of the configuration of the cultivation tank 2, the arrangement position of the pump 17A, a part of the configuration of the cover 12A, and the cover 12A is cultivated. The difference is that the tank 2 is detachably covered. Compared with the cultivation tank 2 of the first embodiment, the cultivation tank 2 of the present embodiment has a configuration of the water supply pipe 14A, a configuration of the plurality of drain holes 13, and a point where the cover 12A is detachably covered, The position of the water level limiting drain 15A is different. Moreover, the cultivation tank 2 of this Embodiment is hold | maintained by the holding member (not shown) in the state which made the upper part of the cultivation tank 2 protrude from the upper surface where the upper end part of the side wall 7b was open | released in the storage tank 7. It is different. The liquid fertilizer in the storage tank 7 is preferably kept at a constant humidity such as 100% humidity and at a constant temperature so that it is not exposed to light and does not evaporate. Therefore, it is preferable to further include a cover (not shown) that covers the storage tank 7 on the outer periphery of the cultivation tank 2. Further, the cover 12A may cover the entire storage tank 7 including the cultivation tank 2. The form of the cover is not limited.

[Cover 12A]
The cover 12A can removably cover the cultivation tank 2 and can be enclosed by one bottom surface 2a and four side walls 2b of the cultivation tank 2. Thereby, not only can the root area of the plant 6 in the cultivation tank 2 be kept at a constant humidity such as a humidity of 100%, but also the root of the plant 6 and the liquid fertilizer can be prevented from being exposed to light. By preventing the liquid fertilizer from being exposed to light, it is possible to prevent the occurrence of unintended things in the liquid fertilizer, such as the occurrence of blue sea bream.

  The cover 12 </ b> A has an opening 12 b at a position corresponding to the placement position of the plant holding unit 5. The opening 12b is provided in a circular shape unlike the rectangular shape of the opening 12a of the cover 12 of the first embodiment, but the shape of the opening 12b is not limited to the circular shape.

  The opening part 12b provided in this way can extend the stem part of the plant 6 planted in the plant holding part 5 placed in the cultivation tank 2 upward. Therefore, the size of the opening 12 b is larger than the stem portion of the plant 6 and smaller than the diameter of the plant holding portion 5. The size of the opening 12b is preferably as small as possible so that light does not enter the root region of the plant 6 from the opening 12b.

  Further, the cover 12A can be removed when the growth of the plant 6 is not progressing, while it cannot be removed when the growth of the plant 6 is progressing, but can be shifted. In addition, the cover 12 may be formed so that it can be divided into two at the center, and can be removed even when the plant 6 grows. By removing or shifting the cover 12, it is possible to check the supply state of liquid fertilizer in the cultivation tank 2, the state of drainage, and the state of the root of the plant 6. Moreover, by removing the cover 12 when necessary, it is possible to efficiently perform operations such as confirmation of the supply state and drainage state of the liquid fertilizer in the cultivation tank 2 and the internal cleaning, as in the first embodiment.

[Water level limiting drain 15A]
The water level limiting drain port 15 </ b> A is erected at one corner of the bottom surface 2 a of the cultivation tank 2. In the example shown in FIGS. 9 and 10, the water level restriction drain 15 </ b> A is erected on the upper left corner of the bottom surface 2 a of the cultivation tank 2 in plan view. The water level limiting drain 15 </ b> A is an inner hole 151 provided for drainage, and has an inner hole 151 that penetrates the bottom surface 2 a and communicates with the inside of the storage tank 7. Since others are the same as those described in the first embodiment, the description thereof is omitted.

[Multiple drain holes 13]
The plurality of drain holes 13 are formed in the cultivation tank 2 as in the first embodiment, and adjust the water level of the liquid manure by draining at least a part of the liquid manure.

  In this Embodiment, the some drainage hole 13 is formed along the horizontal direction in the cultivation tank 2 for every several position of the height direction in the cultivation tank 2. As shown in FIG. For example, as shown in FIGS. 9 and 10, the plurality of drain holes 13 are formed at a predetermined pitch (almost) at a height of a predetermined plurality of steps (here, three steps) from the bottom surface 2 a to the lower portion of the side wall 2 b of the cultivation tank 2. At equal intervals). In other words, the plurality of drain holes 13 includes a plurality of lower drain holes 13a, a plurality of middle drain holes 13b, and a plurality of upper drain holes 13c.

  The plurality of drain holes 13 at any one of the plurality of lower drain holes 13a, the plurality of middle drain holes 13b, and the plurality of upper drain holes 13c are arranged in the installation state such as the inclination of the cultivation tank 2 and the cultivation tank 2 Regardless of the fluctuation of the water level of the liquid fertilizer 21, the liquid fertilizer 21 is positioned below the liquid surface 21 a. Hereinafter, in FIG. 12A, FIG. 12B, and FIG. 12C, in the plant cultivation apparatus 1A of the circulation time, the relationship between the water level of the liquid fertilizer 21 stored in the cultivation tank 2 and the plurality of drain holes 13 is determined as the growth of the root 6a of the plant 6. Explain according to the stages.

  12A, 12B and 12C are explanatory diagrams of the relationship between the water level of the liquid fertilizer 21 in the cultivation tank 2 and the growth of the root 6a of the plant 6 in Embodiment 2. FIG.

  In FIG. 12A, the root 6 a of the plant 6 in the initial state is shown, and the state where the root 6 a of the plant 6 has not reached the vicinity of the side wall 2 b of the cultivation tank 2 is shown. That is, in the growing state of the plant 6 shown in FIG. 12A, the drainage 21d (arrow c) from the plurality of lower drainage holes 13a at the lowest stage is not obstructed by the root 6a at all, so the amount of drainage from the plurality of lower drainage holes 13a. Is defined by the water level of the liquid fertilizer 21 in the cultivation tank 2.

  In this case, since the supply amount of the liquid fertilizer 22 supplied from the water supply pipe 14A to the cultivation tank 2 and the drainage amount from the plurality of lower drainage holes 13a are balanced, the water level of the liquid fertilizer 21 in the cultivation tank 2 is the water level L1. Converge to. In other words, in the growing state of the plant 6 shown in FIG. 12A, the liquid fertilizer 22 is supplied from the water supply pipe 14A so that the water level L1 is higher than the plurality of lower drain holes 13a and lower than the plurality of middle drain holes 13b. The amount is set. As a result, bubbles 21c, which will be described later, that is, bubbles 21c generated below the liquid surface 21a by the discharge liquid 21b from the water supply pipe 14A can reach the periphery of the root 6a.

  FIG. 12B shows the root 6a of the plant 6 in a state in which the growth state of the plant 6 has progressed from the initial state shown in FIG. 12A. The root 6a of the plant 6 grows by growth and a plurality of lower drains at the lowest stage. A state in which the hole 13a is almost blocked is shown. That is, in the growth state of the plant 6 shown in FIG. 12B, the drainage 21d from the plurality of lower drainage holes 13a is inhibited and the amount of liquid decreases, and the water level of the liquid fertilizer 21 in the cultivation tank 2 rises. The drainage of the drainage 21e (arrow d) from the middle drainage hole 13b is started.

  In this case, the amount of liquid fertilizer 22 supplied from the water supply pipe 14A to the cultivation tank 2 is balanced with the amount of drainage from the plurality of lower drainage holes 13a and the plurality of middle drainage holes 13b. The water level converges to the water level L2. In other words, in the growth state of the plant 6 shown in FIG. 12B, the water level L2 is higher than the plurality of middle drain holes 13b and at a height close to the root 6a prospering in the cultivation tank 2. It becomes. Thereby, the bubbles 21c described later can reach the periphery of the root 6a.

  FIG. 12C shows the root 6a of the plant 6 in a state where the growth state of the plant 6 has further progressed from the state shown in FIG. 12B. The root 6a of the plant 6 further grows and a plurality of middle drain holes 13b in the middle stage. The state which has almost blocked is shown. That is, in the growth state of the plant 6 shown in FIG. 12C, the drainage 21e from the plurality of middle drainage holes 13b is inhibited and the amount of liquid is reduced, and the water level of the liquid fertilizer 21 in the cultivation tank 2 further rises. The discharge of the waste water 21f (arrow e) from the plurality of upper drain holes 13c is started.

  In this case, the amount of liquid fertilizer 22 supplied from the water supply pipe 14A to the cultivation tank 2 is balanced with the amount of drainage from the plurality of lower drainage holes 13a, the plurality of middle drainage holes 13b, and the plurality of upper drainage holes 13c. The water level of the liquid fertilizer 21 in the tank 2 converges to the water level L3. In other words, in the growing state of the plant 6 shown in FIG. 12C, the water level L3 is higher than the plurality of upper drainage holes 13c and at a height close to the prosperous root 6a. Thereby, the bubble 21c mentioned later can be reached to the circumference | surroundings of the root 6a.

  In addition, when clogging occurs in the plurality of lower drain holes 13a, the plurality of middle drain holes 13b, and the plurality of upper drain holes 13c for some reason, the liquid fertilizer 21 water level in the cultivation tank 2 has a plurality of upper drain holes 13c. It is also possible to rise beyond the height of. In such a case, when the water level reaches the height of the upper end surface of the water level limiting drain port 15 </ b> A, it overflows from the inner hole 151 and flows down into the storage tank 7. Thereby, the overflow of the liquid manure from the cultivation tank 2 is prevented.

  As described above, the plurality of drain holes 13 make the discharge of the liquid manure in the cultivation tank 2 and the supply of the liquid fertilizer to the cultivation tank 2 by the pump 17 the same during the circulation time in which the pump 17 operates. On the other hand, the plurality of drain holes 13 allow most of the liquid fertilizer 21 in the cultivation tank 2 to be discharged during the interruption time in which the operation of the pump 17A is interrupted, as in the first embodiment, and the roots of the plants 6 are discharged. All of 6a may be exposed. In the present embodiment, one of the plurality of drain holes 13 is mainly used for draining the liquid fertilizer 21 depending on the growth state of the six roots 6a of the plant. For this reason, whether the growth stage of the plant is mainly used for drainage of the liquid fertilizer 21, not the root 6 a of the plant 6 planted in the plant holding unit 5, and the drainage holes 13 in a plurality of stages. You can substitute by confirming. That is, the pump 17 </ b> A may be operated intermittently according to the water level of the liquid fertilizer 21 as the growth of the plant 6.

  Further, the water level of the liquid fertilizer 21 may be determined by a float sensor floating on the liquid fertilizer 21 by visual observation or photographing means such as a camera as in the first embodiment.

<Water supply pipe 14A>
14 A of water supply pipes are arrange | positioned above the cultivation tank 2, and the liquid level of the liquid fertilizer 21 collected in the cultivation tank 2 is dropped by dropping a part of the liquid fertilizer 22 stored in the storage tank 7 supplied by the pump 17A. It is an example of the bubble generation part which generates the bubble 21c in 21a. Moreover, 14 A of water supply pipes drop a part of liquid manure 22 on the liquid level 21a above the root extended from the plant 6 between the plant holding part 5 and the side wall 2b.

  In this Embodiment, the water supply pipe 14A is arrange | positioned so that it may be located in the upper part inside the cultivation tank 2. FIG. In the example shown in FIGS. 9 to 11, the water supply pipe 14 </ b> A is arranged in a first direction so that a plurality (here, two) of pipes sandwich the plant holding part 5 in plan view.

  Further, as shown in FIG. 11, the water supply pipe 14A is attached in a state of being laid between two opposing side walls 2b. The water supply pipe 14 </ b> A is attached at a position above the height of the liquid surface 21 a in a state where the liquid fertilizer 21 is accumulated in the cultivation tank 2 at a higher water level than the uppermost upper drainage hole 13 c.

  Moreover, 14 A of water supply pipes are connected with the connection pipe 16 piped outside the cultivation tank 2 similarly to Embodiment 1, and as shown by the arrow a of FIG. Will be sent. Further, on the lower surface of the water supply pipe 14A, a liquid hole (not shown) for discharging the liquid fertilizer 22 fed through the connection pipe 16 as the liquid fertilizer 21 in the form of a thin discharge liquid 21b by the pressure of the pump 17A is predetermined. A plurality of pitches are formed.

  Thus, by disposing the water supply pipe 14A above the liquid surface 21a of the liquid manure 21, one or more liquid holes provided for the water supply pipe 14A to discharge the liquid fertilizer 22 are formed by the root 6a of the plant 6. It is possible to prevent clogging and supply of liquid fertilizer 22 can be performed stably.

  Further, the liquid fertilizer 22 fed to the water supply pipe 14A falls as a discharge liquid 21b from the liquid hole on the lower surface of the water supply pipe 14 toward the liquid surface 21a of the liquid fertilizer 21 accumulated in the cultivation tank 2 (in FIG. 10). Arrow b). And the bubble 21c generate | occur | produces in the liquid level 21a of the liquid manure 21 by fall of the discharge liquid 21b. In other words, the water supply pipe 14A generates bubbles 21c on the liquid surface 21a by discharging and dropping the discharge liquid 21b from the liquid holes.

Thus, since the water supply pipe 14A can generate the bubbles 21c on the liquid surface 21a of the liquid manure 21 accumulated in the cultivation tank 2, the contact area between the liquid fertilizer 21 and the air in the bubbles 21c can be increased. . Thereby, since the oxygen supply amount in the liquid fertilizer 21 can be increased even during the circulation time, the oxygen uptake amount of the root of the plant 6 can be increased, and the growth of the plant 6 can be promoted. That is, since the oxygen supply amount in the liquid fertilizer 21 can be increased and the dissolved oxygen concentration can be made uniform during the circulation time, the variation in the growth state of the plant 6 can be further suppressed.
The

[Pump 17A]
Similarly to the first embodiment, the pump 17A performs an intermittent operation in which the ratio of the interruption time to the circulation time is adjusted by the pump control unit 19 according to the growth of the plant 6.

  In the present embodiment, the pump 17A is arranged at the upper right corner portion of the bottom portion 7a of the storage tank 7 in plan view, as shown in FIGS. Since others are the same as those described in the first embodiment, the description thereof is omitted.

[Flow state of liquid fertilizer 21 in cultivation tank 2]
Next, the flow state of the liquid fertilizer 21 in the cultivation tank 2 will be described with reference to FIG.
FIG. 13 is a schematic top view of the cultivation tank 2 showing the flow state of the liquid fertilizer 21 in the second embodiment.

  As described above, in the plant cultivation apparatus 1A of the circulation time, the supply of the liquid fertilizer 21 into the cultivation tank 2 is performed by dropping the liquid fertilizer 22 as the discharge liquid 21b from the water supply pipe 14A arranged inside the cultivation tank 2. Is called. Moreover, the drainage of the liquid fertilizer 21 from the cultivation tank 2 is performed through the drainage hole 13 formed in the side wall 2b of the cultivation tank 2.

  Therefore, in the cultivation tank 2 of the plant cultivation apparatus 1A of the circulation time, as shown in FIG. 13, the flow (arrow f) of the liquid fertilizer 21 in the direction from the center of the cultivation tank 2 toward each side wall 2b is induced. Here, a plurality of drainage holes 13 are formed at substantially equal intervals at a predetermined height (each of a plurality of predetermined heights) of the four side walls 2b of the cultivation tank 2. This also shows that a substantially uniform flow state is generated in the entire range in the cultivation tank 2.

  Thereby, even if the root of the plant 6 extends from the plant holding part 5 toward the peripheral side wall 2b in the cultivation tank 2 and grows over the entire bottom surface 2a, the liquid fertilizer 21 that flows in the circulation time is supplied to the plant 6. It is possible to make contact with the entire root of the plant evenly and evenly. Therefore, since nutrients and oxygen can be uniformly supplied to the entire root of the plant 6 even during the circulation time, variations in the growth state of the plant 6 can be further prevented.

[Effects]
As mentioned above, according to Embodiment 2, the plant cultivation apparatus 1 which can suppress the temperature rise of liquid manure and the oxygen shortage in a root surface is realizable by operating the pump which circulates liquid manure intermittently. Furthermore, according to the second embodiment, even during the circulation time, the oxygen supply amount in the liquid fertilizer can be increased, and the dissolved oxygen concentration can be made uniform to realize a good growth state.

  More specifically, in the plant cultivation apparatus 1A in the present embodiment, for example, the plurality of drain holes 13 are formed along the horizontal direction in the cultivation tank for each of a plurality of positions in the height direction in the cultivation tank 2. The pump controller 19 may intermittently operate the pump 17 </ b> A according to the water level of the liquid fertilizer 21 as the growth of the plant 6.

  Thereby, in the circulation time, since the liquid fertilizer 21 supplied from the water supply pipe 14A and stored in the cultivation tank 2 is discharged outside the cultivation tank 2 without staying, the dissolved oxygen concentration of the liquid fertilizer 21 in the cultivation tank 2 Can be kept substantially uniform. That is, the liquid fertilizer 21 that flows during the circulation time can be brought into uniform contact with the entire root of the plant 6 almost uniformly. Therefore, since nutrients and oxygen can be uniformly supplied to the entire root of the plant 6 even during the circulation time, it is possible to suppress poor growth of the plant 6 due to lack of oxygen and nutrition.

  Furthermore, by providing such a plurality of drain holes 13, the water level of the liquid fertilizer 21 in the cultivation tank 2 can be sequentially increased in accordance with the growth of the roots of the plant 6.

  More specifically, in the conventional hydroponics, the state in which the root that grows thick with the growth of the plant 6 and increases in thickness cannot be properly immersed in the liquid fertilizer 21. Therefore, the water level of the liquid fertilizer 21 in the cultivation tank 2 is adjusted by a method such as adjusting the amount of water supplied from the water supply pipe 14. On the other hand, in the plant cultivation apparatus 1A in the present embodiment, the cultivation tank 2 has a simple configuration in which a plurality of drain holes 13 formed at a plurality of positions in the height direction are provided on the side wall 2b of the cultivation tank 2. The water level of the liquid fertilizer 21 in the inside can always be maintained appropriately.

  Moreover, for example, the liquid of the liquid fertilizer 21 stored in the cultivation tank 2 by dropping a part of the liquid fertilizer 22 that is disposed above the cultivation tank 2 and stored in the storage tank 7 supplied by the pump 17 </ b> A as the liquid fertilizer 21. A water supply pipe 14A for generating bubbles 21c on the surface 21a may be provided.

  Thus, since the water supply pipe 14A is disposed above the liquid surface 21a of the liquid fertilizer 21, the liquid hole provided for discharging a part of the liquid fertilizer 22 in the water supply pipe 14A has a root 6a of the plant 6. Can be prevented from being blocked. That is, the water supply pipe 14 </ b> A can stably supply the liquid fertilizer 22.

  Furthermore, since the water supply pipe 14A can generate bubbles 21c on the liquid surface 21a of the liquid manure 21 accumulated in the cultivation tank 2, the contact area between the liquid fertilizer 21 and the air in the bubbles 21c can be increased. Thereby, since the oxygen supply amount in the liquid fertilizer 21 can be increased, the oxygen uptake amount of the root of the plant 6 can be increased, and the growth of the plant 6 can be promoted. That is, even during the circulation time, the oxygen supply amount in the liquid fertilizer 21 can be increased and the dissolved oxygen concentration can be made uniform, so that the growth failure of the plant 6 due to oxygen deficiency and nutrient deficiency can be suppressed.

  Here, for example, the water supply pipe 14A may drop a part of the liquid fertilizer 22 on the liquid surface 21a above the root extending from the plant 6 between the plant holding unit 5 and the side wall 2b.

  In this way, the water supply pipe 14 </ b> A can drop the discharge liquid 21 b at a plurality of locations on the liquid surface 21 a above the root extending between the plant holding part 5 and the side wall 2 b as the plant 6 grows. . Thereby, since the water supply pipe 14A can generate the bubbles 21c almost evenly in the liquid fertilizer 21 around the root of the plant 6 extending toward the side wall 2b of the cultivation tank 2, the dissolved oxygen in the liquid fertilizer 21 also in the circulation time. The concentration can be kept uniform.

(Embodiment 3)
Although Embodiment 2 demonstrated that 1 A of plant cultivation apparatuses and the cultivation tank 2 had a substantially square planar shape, it is not restricted to this. This Embodiment demonstrates the case where the plant cultivation apparatus 1B and the cultivation tank 2B have a rectangular planar shape long in one direction. Hereinafter, a description will be given focusing on differences from the second embodiment.

[Configuration of plant cultivation apparatus 1B]
FIG. 14 is a schematic plan view of the plant cultivation apparatus 1B in the third embodiment. Also in FIG. 14, the first direction is a direction in which the water supply pipe 14 </ b> A is extended, and the direction orthogonal to the first direction will be described as the second direction. In addition, the same code | symbol is attached | subjected to the element similar to FIG. 11 etc., and detailed description is abbreviate | omitted.

  The plant cultivation device 1B has a rectangular planar shape that is long in one direction, a point having a plurality of plant holding units 5, and a shape of the cultivation tank 2B, as compared with the plant cultivation device 1A of the second embodiment. And the structure accompanying it and the shape of the cover 12B differ.

[Cover 12B]
The cover 12B detachably covers the cultivation tank 2B, and a plurality of openings 12b are provided at positions corresponding to the mounting positions of the plurality of plant holding units 5. Since others are as described above, the description thereof is omitted.

[Cultivation tank 2B]
In this Embodiment, compared with the cultivation tank 2 of Embodiment 2, the cultivation tank 2B has the point which has a rectangular planar shape long in one direction, and the shape of the water supply pipe 14A is the shape of the cultivation tank 2B. The point which became long in one direction collectively and the point which can hold | maintain the some plant holding part 5 differ.

More specifically, the cultivation tray 2B, as shown in FIG. 14, the side wall 2b ₁ extending in the first direction has a long rectangular shape in plan view than the side wall 2b ₂ extending in a second direction. And the cultivation tank 2B is provided with a plurality of (here, three) pot placement portions 4 (not shown) on which the plant holding portions 5 are placed along the first direction which is the longitudinal direction. Yes.

Further, the two opposing side walls 2b ₁ and 2b ₂ of the cultivation tank 2B are composed of a plurality of lower drain holes 13a, a plurality of middle drain holes 13b, and a plurality of upper drain holes 13c, as in the second embodiment. A plurality of drain holes 13 are formed.

Furthermore, cultivation tray 2B has a water supply pipe 14A mounted in bridged state between two opposing side walls 2b _1. As in the second embodiment, the water supply pipe 14A is arranged in the first direction so that a plurality of (here, two) pipes sandwich the plurality of plant holding parts 5 in a plan view. The length matches the shape.

  Other configurations are the same as described above, and a description thereof will be omitted.

[Storage tank 7B]
In the present embodiment, the storage tank 7B is different from the storage tank 7 of Embodiment 2 in that it has a rectangular planar shape that is long in one direction according to the shape of the cultivation tank 2B.

  More specifically, the storage tank 7B has a rectangular planar shape in which the first direction is longer than the second direction. The storage tank 7B has a function of storing liquid manure drained from the plurality of drain holes 13 of the cultivation tank 2B, similarly to the storage tank 7 in the second embodiment. Other configurations are the same as described above, and thus description thereof is omitted.

[Effects]
As mentioned above, according to Embodiment 3, the plant cultivation apparatus 1B which can suppress the temperature rise of liquid manure and the oxygen shortage in a root surface is realizable by operating the pump which circulates liquid manure intermittently.

Also in the third embodiment, liquid manure supplied from the water supply pipe 14A is located near the center of the second direction in the cultivation tray. 2B, first towards the plurality of drain holes 13 of the side wall 2b ₁ is a long side Flows in two directions. Here, a plurality of drain holes 13 in the side wall 2b ₁ are arranged at a predetermined pitch along the first direction which is the longitudinal direction. For this reason, the flow state of the liquid fertilizer in the second direction in the cultivation tank 2B becomes uniform in the first direction, and the same effect as in the second embodiment can be obtained.

  Also in the third embodiment, the contact area between the liquid fertilizer and the air in the bubbles can be increased. Thereby, since the oxygen supply amount in the liquid fertilizer can be increased even during the circulation time, the oxygen uptake amount of the root of the plant 6 can be increased, and the growth of the plant 6 can be promoted. That is, in the circulation time, the oxygen supply amount in the liquid fertilizer can be increased and the dissolved oxygen concentration can be made uniform, so that the growth failure of the plant 6 due to oxygen deficiency and nutrient deficiency can be suppressed.

[Possibility of other embodiments]
As mentioned above, although the plant cultivation apparatus and the plant cultivation method which concern on 1 aspect of this indication were demonstrated based on embodiment, this indication is not limited to these embodiment. Unless it deviates from the gist of the present disclosure, forms in which various modifications conceived by those skilled in the art have been made in the present embodiment, or forms constructed by combining components in different embodiments are also included in the scope of the present disclosure. .

  The present disclosure also includes the following cases.

  For example, in the second and third embodiments, the water supply pipe 14A including a plurality of pipes is used, but the present invention is not limited to this. For example, a water supply pipe formed by connecting a plurality of pipes into an annular shape may be used.

  Moreover, although the several drainage hole 13 demonstrated as having formed only in the side wall of the cultivation tank in the said embodiment, you may form in both the side wall 2b and the bottom face 2a.

  Moreover, although the said embodiment demonstrated that the storage tank was arrange | positioned directly under the cultivation tank, it is not restricted to this. A storage tank may be arrange | positioned in the position away from the cultivation tank in the horizontal direction, and liquid fertilizer discharged | emitted from the several drainage hole 13 formed in the cultivation tank may be collected by a drainage duct etc., and you may make it collect | recover in a storage tank. .

  In addition, the plant cultivation apparatus and the plant cultivation method according to one embodiment of the present disclosure increase the oxygen supply amount in liquid fertilizer and can achieve a good growth state by making the dissolved oxygen concentration uniform, so that the hydroponic plant It can also be used in plant factories that grow potatoes. Here, a plant factory is a production system that grows vegetables or flowers in a planned and stable manner throughout the year by highly artificially controlling the environmental conditions necessary for plant growth in the facility. In other words, it can be said that the plant factory performs agriculture in an industrial form such as cultivation and production of plants such as vegetables.

  The present disclosure can be used for a plant cultivation apparatus and a plant cultivation method, and particularly used in a plant factory. It can be used for plant cultivation methods.

DESCRIPTION OF SYMBOLS 1, 1A, 1B Plant cultivation apparatus 2, 2B Cultivation tank 2a Bottom surface 2b, 2b ₁ , 2b ₂ , 7b Side wall 4 Pot mounting part 5 Plant holding part 6 Plant 6a Root 7, 7B Storage tank 7a Bottom part 12, 12A, 12B Cover 12a, 12b Opening 13 Drainage hole 13a Lower drainage hole 13b Middle drainage hole 13c Upper drainage hole 14, 14A Water supply pipe 15, 15A Water level limiting drainage 16 Connection pipe 17, 17A Pump 18 Root-proof permeation sheet 21, 22 Liquid fertilizer 21a Liquid level 21c Air bubbles 21d, 21e, 21f Drainage 151 Inner hole

Claims (15)

A plant cultivation apparatus for cultivating a plant by immersing the root of the plant in liquid fertilizer,
A plant holding unit that holds the plant and is capable of passing the roots extended from the plant to the outside;
A cultivation tank in which the plant holding part is placed and is capable of storing the liquid fertilizer and has a bottom surface that receives roots extending from the plant and a side wall that surrounds the plant holding part,
A plurality of drainage holes that are formed in the cultivation tank and adjust the water level of the liquid fertilizer by draining at least a part of the liquid fertilizer;
A storage tank capable of storing the at least part drained from the drain hole;
A pump that circulates the liquid fertilizer by supplying the at least part of the storage tank to the cultivation tank;
A pump control unit that performs control to intermittently operate the pump,
The pump control unit adjusts a ratio of an interruption time that is a time for interrupting the operation of the pump to a circulation time that is a time for performing the operation of the pump according to the growth of the plant.
Plant cultivation equipment. The interruption time is equal to or longer than the time when the drainage hole is adjusted to the water level of the liquid fertilizer where all the roots of the plant are exposed.
The plant cultivation apparatus according to claim 1. The pump controller
As the root growth of the plant progresses, the intermittent operation is controlled so that the ratio of the interruption time to the circulation time increases.
The plant cultivation apparatus of Claim 1 or 2. The pump controller
In the direction after the flowering of the plant than before the flowering of the plant, the control is performed to perform the intermittent operation in which the ratio of the interruption time to the circulation time is increased.
The plant cultivation apparatus of any one of Claims 1-3. The plurality of drain holes are formed along the horizontal direction in the cultivation tank for each of a plurality of positions in the height direction in the cultivation tank,
The pump controller
Depending on the water level of the liquid fertilizer as the growth of the plant, the pump is operated intermittently,
The plant cultivation apparatus of any one of Claims 1-4. The cultivation tank further has a root guard (18) for preventing the root of the plant from entering the drain hole.
The plant cultivation apparatus of any one of Claims 1-5. The storage tank is disposed below the cultivation tank, and at least the lower end of the cultivation tank is disposed inside.
The plant cultivation apparatus of any one of Claims 1-6. The distance from the plant holding part to the side wall is a distance that the root extending from the plant can reach,
The plant cultivation apparatus of any one of Claims 1-7. Furthermore, bubbles are generated on the liquid surface of the liquid fertilizer stored in the cultivation tank by dropping the at least part of the storage tank that is disposed above the cultivation tank and supplied by the pump. With a bubble generator,
The plant cultivation apparatus of any one of Claims 1-8. The bubble generating unit drops the at least a part on the liquid surface above the root extending from the plant between the plant holding unit and the side wall,
The plant cultivation apparatus according to claim 9. A plant cultivation method by a plant cultivation apparatus for cultivating a plant by immersing the root of the plant in liquid fertilizer accumulated in a cultivation tank,
Cultivation tank that holds the plant and is capable of storing the liquid fertilizer on which a plant holding unit that holds the plant and is capable of passing a root extending from the plant to the outside. The liquid fertilizer is drained by draining at least a part of the liquid fertilizer into a plurality of drain holes formed in a cultivation tank having a bottom surface that receives roots extending from the plant and a side wall that surrounds the plant holding part. A water level adjustment step for adjusting the water level;
A control step for performing intermittent operation of the pump;
A circulation step of circulating the liquid manure by causing the pump to supply the cultivation tank with the at least a part of the storage tank that can store the at least a part of the pump drained from the drain hole. Including
In the control step, according to the growth of the plant, the ratio of the interruption time that is the time for interrupting the operation of the pump to the circulation time that is the time for performing the operation of the pump is adjusted.
Plant cultivation method. The interruption time is not less than the time adjusted by the drainage hole to the water level of the liquid manure where all the roots of the plant are exposed.
The plant cultivation method according to claim 11. In the control step,
As the root growth of the plant progresses, the intermittent operation is controlled so that the ratio of the interruption time to the circulation time increases.
The plant cultivation method according to claim 11 or 12. In the control step,
In the direction after the flowering of the plant than before the flowering of the plant, the control is performed to perform the intermittent operation in which the ratio of the interruption time to the circulation time is increased.
The plant cultivation method of any one of Claims 11-13. The plurality of drain holes are formed along the horizontal direction in the cultivation tank for each of a plurality of positions in the height direction in the cultivation tank,
In the control step,
Depending on the water level of the liquid fertilizer as the growth of the plant, the pump is operated intermittently,
The plant cultivation method of any one of Claims 11-14.

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