Plant cultivation device and method

Abstract

Provided is a plant cultivation device with which it is possible to adequately apply air (air current) to plants cultivated in a cultivation bed. A conveying device 10 for cultivation beds 4 is installed on multiple vertical levels. The length direction of the cultivation beds 4 is set to be orthogonal to the conveying direction of the conveying device 10. Blower ducts 23, 24 are provided so as to apply an air current from above to plants in the cultivation beds 4 on each level of the conveying device 10. Spaces for passing the air current below are provided between the cultivation beds 4 conveyed by the conveying device 10.

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for cultivating plants. [Background technology]

[0002] Patent Document 1 describes a plant cultivation device for cultivating plants such as vegetables, in which cultivation bed transport units are installed in multiple levels, one above the other, and the cultivation beds are moved sequentially.

[0003] In Patent Document 1, a roughly rectangular lighting and ventilation panel is arranged to cover the top of multiple cultivation beds in each transport section, and air is blown toward the plants from a ventilation pipe or fan installed in this lighting and ventilation panel (paragraphs 0016 and 0020, Figure 2 of the patent document).

[0004] Patent Document 2 describes a plant cultivation device in which seedling raising shelves are arranged in multiple levels. In Patent Document 2, a back panel is provided at the rear of the seedling raising space between each seedling raising shelf, and this back panel is provided with vents, and an air fan is installed in this vent. By operating the air fan, airflow is supplied to the seedling raising space through the vents. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-216685 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-55720 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 2, the air current flows from the rear to the front within the seedling raising space, so it is difficult for the air current to get into the gaps between adjacent cultivation beds on the same plane.

[0007] In Patent Document 1, air is blown onto the plants from air ducts or fans installed on lighting and air-blowing panels above each transport section (Patent Document 1, paragraph 0020, line 4), but because these lighting and air-blowing panels are installed at each transport section, the air blown onto the plants flows sideways after hitting the plants, and hardly gets into the spaces between adjacent cultivation beds on the same plane.

[0008] As described above, in conventional plant cultivation devices, most of the wind flows above the plants, making it difficult for the wind to directly hit the growing points of vegetables and other plants, and reducing the uniformity of the air currents (wind) around the plants, which could lead to growth disorders such as chip burn.

[0009] In one aspect, the present invention aims to provide a plant cultivation device and method that can provide sufficient wind (airflow) to plants cultivated in a cultivation bed.

[0010] Another object of the present invention, in one aspect, is to provide a plant cultivation device and method in which the influence of shading of lighting by an air outlet duct for sending air currents is small.

[0011] Another object of the present invention is to provide a plant cultivation device and method that allows for a long distance between the lighting and the cultivation surface.

[0012] Another object of the present invention, in one aspect, is to provide a plant cultivation device and method that can improve temperature uniformity in a cultivation section that has a long width and depth and a wide surface. [Means for solving the problem]

[0013] The present invention has the following gist.

[0014] [1] A conveying unit equipped with a conveying device for conveying a plurality of cultivation beds is provided, A plant cultivation device provided with a blower means for blowing air toward the plants in the cultivation beds on the conveying device, The conveying section has two or more stages, The air blower is provided at each stage of the conveying section, A plant cultivation device characterized in that the conveying device is provided with a space for allowing the air current to pass between the cultivation beds and through the bottom surface of the conveying device.

[0015] [2] The plant cultivation device according to [1], wherein the cultivation beds are spaced apart from one another by 40 to 500 mm.

[0016] [3] The plant cultivation device of [1] or [2], wherein the air blowing means comprises an air conditioner that draws in air from the cultivation room in which the plant cultivation device is installed and conditioned air at a predetermined temperature range, and an outlet duct that supplies conditioned air that is a mixture of the conditioned air from the air conditioner and the air from the cultivation room and blows the conditioned air toward the cultivation bed.

[0017] [4] The plant cultivation device according to [3], wherein the blow-out duct is installed along the conveying direction of the conveying device.

[0018] [5] The plant cultivation device according to any one of [1] to [4], wherein the conveying units are installed in multiple vertical stages.

[0019] [6] The plant cultivation device according to any one of [1] to [5], wherein the longitudinal direction of the cultivation bed is a direction intersecting the transport direction of the transport device.

[0020] [7] A conveying section is provided with a conveying device for the cultivation bed; A plant cultivation device provided with a blower means for blowing airflow from above onto plants in a cultivation bed on a conveying device, a lighting device for irradiating light onto the plants in the cultivation bed; A plant cultivation device in which an air outlet duct is arranged between at least some of the lights.

[0021] [8] The conveying section has two or more stages, The air blower is provided at each stage of the conveying section, The plant cultivation device according to [7], wherein the conveying section and the conveying device are provided with a space for allowing the airflow to pass between the cultivation beds and through the bottom surface of the conveying section.

[0022] [9] A plant cultivation device in which lighting is installed along the direction of the air outlet duct and the PPF output of the lighting per 1 m is 150 μmol / s or more.

[0023]

[10] A cultivation bed and the lighting device disposed above the cultivation bed, The PPFD value on the top surface of the cultivation bed is 100 to 1000 μmol / m 2 A plant cultivation device according to any of [7] to [9].

[0024]

[11] The plant cultivation device according to any one of [7] to

[10] , wherein the height from the top surface of the cultivation bed to the lighting is 300 to 1500 mm.

[0025]

[12] A plant cultivation device according to any one of [7] to

[11] , wherein the upper limit of the spacing (y) between the lights is calculated from the height (x) from the top surface of the cultivation bed to the light and the half value (θ) of the half value angle 2θ of the light using the following formula (1):

[0026]

number

[0027] In formula (1), y: Lighting installation interval [cm], x: Height from the top of the cultivation bed to the lighting [cm] θ: Half value of the illumination half-value angle 2θ [°].

[0028]

[13] The plant cultivation device according to any one of [7] to

[12] , wherein the lighting is an LED lighting, and the installation range of the air outlet duct is outside the light distribution range of the half-value angle 2θ of the LED lighting.

[0029]

[14] A plant cultivation device according to any one of [7] to

[13] , characterized in that the cross-sectional area (S) of the air outlet duct has an upper limit of a value calculated by the following formula (2) from the effective width (a) above the lighting, the installation interval (y) of the lighting, and the half-value of the half-value angle (θ) of the lighting:

[0030]

number

[0031] In formula (2), S: Cross-sectional area of ​​the outlet duct [cm 2 ], a: Effective width above the light source [cm] y: Lighting installation interval [cm], θ: Half value of the illumination half-value angle 2θ [°].

[0032]

[15] The plant cultivation device according to any one of [7] to

[14] , wherein the cross section of the air outlet duct is approximately circular, and the upper limit of the diameter (R) of the air outlet duct is calculated from the effective width (a) above the lighting and the installation interval (y) of the lighting by the following formula (3):

[0033]

number

[0034] In formula (3), R: diameter of the outlet duct [cm], a: Effective width above the light source [cm] y: Lighting installation interval [cm], θ: Half value of the illumination half-value angle 2θ [°].

[0035]

[16] The plant cultivation device according to any one of [1] to

[15] , wherein the cultivation bed is covered with a cultivation plate having planting holes.

[0036]

[17] The plant cultivation device according to

[16] , wherein the planting holes are arranged in a row in the longitudinal direction of the cultivation bed.

[0037]

[18] A plant cultivation device in which the temperature difference between the cultivation beds on each level is within ±1°C.

[0038]

[19] A plant cultivation device according to any one of [1] to

[18] , wherein both the vertical and horizontal dimensions of one cultivation surface are 2m or more.

[0039]

[20] A plant cultivation method for cultivating plants using the plant cultivation device according to any one of [1] to

[19] .

[0040]

[21] The plant cultivation method according to

[20] , wherein the plant is a leafy vegetable such as a member of the Asteraceae family, such as frilled lettuce, batavia, and lettuce, a member of the Brassicaceae family, such as komatsuna and bok choy, a member of the Amaranthaceae family, such as spinach, a member of the Rosaceae family, such as strawberry, or a member of the Solanaceae family, such as tomato. [Effects of the Invention]

[0041] According to one aspect of the present invention, conditioned air can be directly supplied to the area surrounding the growing point of plants in a cultivation bed. This prevents growth disorders such as tip burn and increases harvest weight. Furthermore, the cultivation environment for each plant is made uniform, allowing plants of consistent quality to be cultivated.

[0042] In addition, in one aspect of the present invention, the effect of shading lighting by an air outlet duct for distributing airflow can be reduced, allowing air to be blown from above the plant body, resulting in a larger cultivation surface.

[0043] According to one aspect of the present invention, the temperature uniformity in the cultivation area can be improved by increasing the distance between the plants and the lighting and the air duct. [Brief explanation of the drawings]

[0044] [Figure 1] 2. FIG. 3 is a cross-sectional view of the plant cultivation device according to the embodiment, taken along line II in FIG. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a schematic perspective view showing the configuration of a transport device and a cultivation bed. [Figure 4] FIG. 2 is a schematic perspective view showing the relationship between the cultivation bed and the duct. [Figure 5] FIG. [Figure 6] FIG. 10 is an explanatory diagram illustrating a calculation formula. DETAILED DESCRIPTION OF THE INVENTION

[0045] Hereinafter, a plant cultivation device according to an embodiment will be described with reference to the drawings. Note that, as described above, Fig. 3 is a schematic perspective view showing the configuration of the conveying device and the cultivation bed, but in Fig. 3, the length of the cultivation bed is illustrated shorter than the actual length, and the actual cultivation bed is longer than shown in Fig. 3.

[0046] As shown in FIGS. 1 and 2, two conveying units for conveying a plurality of cultivation beds 4 are installed in a cultivation room 3 surrounded by walls 1 and a ceiling 2, one above the other. Each conveying unit is equipped with a conveying device 10 for conveying a plurality of cultivation beds 4. The conveying unit may include a drive unit for the conveying device in addition to the conveying device 10. In this embodiment, the drive unit includes a cylinder 13, which will be described later. The upper side of each conveying device 10 is equipped with a blowing means for sending airflow toward the plants. In this embodiment, above each conveying device 10, blowing ducts 23 and 24 for air (airflow) and lighting 28 are installed as blowing means. As shown in FIG. 2, conditioned air conditioned to a predetermined temperature by an air conditioner 20 is supplied to the blowing duct 23 via a main duct 21. In this embodiment, the air conditioner 20 is further included as a blowing means. The air conditioner 20 conditioned the air in the cultivation room in which the plant cultivation device is installed to a predetermined temperature range.

[0047] The conveying device 10 is provided to convey the cultivation bed 4 from left to right in Fig. 1 on the upper side, and from right to left in Fig. 1 on the lower side. The conveying device 10 is disposed below one end side and the other end side in the longitudinal direction of the cultivation bed 4. The conveying device 10 may be disposed from one end side to the other end side in the longitudinal direction of the cultivation bed 4, or from the other end side to one end side.

[0048] An elevation table 30 is installed to transfer the cultivation bed 4, which has been transported to the right end of Fig. 1 by the upper-stage transport device 10, to the lower-stage transport device 10. The elevation table 30 can be raised and lowered between the upper-stage and lower-stage transport devices 10 by a drive machine (not shown).

[0049] As will be described in detail later, the cultivation bed 4 is configured so that seedlings are inserted into planting holes 6 provided in the cultivation plate 5 and hydroponically cultivated with liquid fertilizer.

[0050] Each conveying device 10, the outlet ducts 23, 24, and the lighting 28 are supported by a frame 8 (Fig. 2). The frame 8 also supports a liquid supply pipe 40 (Figs. 2 and 3) for supplying liquid fertilizer to one end of each cultivation bed 4, and a trough-shaped drainage tray 42 (Figs. 2 and 3) for receiving liquid fertilizer flowing out from the other end of each cultivation bed 4.

[0051] Liquid fertilizer in a liquid fertilizer tank (not shown) can be supplied to one end of a liquid fertilizer supply pipe 40 by a pump.

[0052] In this embodiment, the cultivation bed 4 is a long, gutter-shaped bed with an open top, and its cross section perpendicular to the longitudinal direction is an upward U-shape. In this embodiment, the cultivation bed 4 is arranged in a direction intersecting the transport direction of the transport device 10. It is preferable that the cultivation bed 4 is arranged in a perpendicular direction. The cultivation bed 4 is not limited to a long bed, and may have a shape in which the width and depth are approximately the same.

[0053] Liquid fertilizer is supplied to one end of the cultivation bed 4 from a liquid supply pipe 40 via a nozzle 41. The bottom surface of the cultivation bed 4 has a flow gradient from the one end to the other end in the longitudinal direction, and the liquid fertilizer flows from the one end to the other end within the cultivation bed 4 and flows out into a drainage tray 42.

[0054] The drainage tray 42 is installed so as to have a flow gradient. The liquid fertilizer flowing out from the downstream end of the drainage tray 42 is returned to the liquid fertilizer tank via a collecting pipe (not shown).

[0055] A lid-shaped cultivation plate 5 is attached to the top surface of the cultivation bed 4. The cultivation plate 5 has a large number of planting holes 6 spaced apart in the longitudinal direction. In this embodiment, the planting holes 6 are arranged in a single row in the longitudinal direction of the cultivation plate 5, but they may also be arranged in two or more rows.

[0056] The planting holes 6 penetrate the cultivation plate 5. Young seedlings (not shown) are inserted into the planting holes 6 from above. The seedlings are inserted into the planting holes 6 so that the roots of the seedlings come into contact with the liquid fertilizer flowing along the bottom of the cultivation bed 4.

[0057] The cultivation beds 4 are slidably arranged on guide rails 18 extending in the conveying direction. As shown in Figures 3 and 5, the conveying device 10 that moves the cultivation beds 4 on the guide rails 18 in the conveying direction includes a rod 11 having a U-shaped cross section perpendicular to the longitudinal direction, claws 12 provided on the rod 11, and a cylinder (an air cylinder in this embodiment) 13 that reciprocates the rod 11 in the longitudinal direction. One end of the rod 11 is connected to a piston rod 13a of the cylinder 13. The claws 12 are provided at intervals in the longitudinal direction of the rod 11.

[0058] The claw 12 is tiltably attached to the rod 11 by a pivot pin 14. The claw 12 is in a position where it protrudes from the upper surface of the rod 11 due to the weight of the part below the pivot pin 14.

[0059] When the rod 11 moves in the conveying direction (forward movement direction) due to the protrusion of the piston rod 13a, the claws 12 come into contact with the lower part of the side surface of the cultivation bed 4. Then, as the rod 11 moves forward, the cultivation bed 4 is pushed by the claws 12 and moves forward.

[0060] The claws 12 are inclined toward the downstream side of the conveying direction of the cultivation bed 4, and when the piston rod 13a is retracted and the rod 11 moves in the opposite conveying direction (returning direction), the claws 12 rotate (tilt) around the axis pin 14 so as to slip under the cultivation bed 4, so that the claws 12 do not protrude from the rod 11, and the rod 11 retracts without the claws 12 getting caught on the cultivation bed 4.

[0061] As described above, this embodiment employs an intermittent movement mechanism in which each cultivation bed 4 moves downstream in the conveying direction by the stroke length of the piston rod 13a for each protruding stroke of the piston rod 13a of the cylinder 13. The stopping position of the cultivation bed 4 is below each liquid supply nozzle 41.

[0062] Each liquid supply nozzle 41 is provided with a valve, which opens to discharge liquid fertilizer from the nozzle 41 only when the cultivation bed 4 is stopped below the nozzle 41. When the cultivation bed 4 is moving, the valve closes to stop discharge.

[0063] In each transport section, the cultivation beds 4 are transported so that a predetermined interval D (FIG. 3) is provided between the cultivation beds 4 transported on the transport device 10. The interval D is preferably 40 to 500 mm. Specifically, the appropriate spacing varies depending on the type of plant and the early to late stages of cultivation, but for leaf lettuce, approximately 45mm to 90mm is suitable in the early stages of cultivation, 90mm to 135mm in the middle stages of cultivation, and 135mm to 180mm in the late stages of cultivation.

[0064] In this embodiment, as shown in Figure 1, the distance D between the conveying sections on the lower level is greater than the distance D between the conveying sections on the upper level. This is because the plants grow more on the lower level than on the upper level.

[0065] When leafy vegetables, particularly leaf lettuce, are grown in two tiers, the upper tier conveyor corresponds to the early to mid-cultivation stage. Therefore, the spacing D is the same as that from the early to mid-cultivation stage, and is preferably about 45 mm to 135 mm. The lower tier conveyor corresponds to the mid-cultivation stage to the late cultivation stage, and the spacing D is the same as that from the mid-cultivation stage to the late cultivation stage, and is preferably about 90 mm to 180 mm. Note that, depending on the type of plant, leafy vegetables with spreading leaves, such as leaf lettuce and salad greens, have a spacing of 45 mm to 180 mm. Leafy vegetables with upright leaves, such as green onions and arugula, do not require a significant change in spacing from the early to late cultivation stages, and therefore are preferably about 45 mm from the early to late cultivation stages.

[0066] The blow-out duct 23 is disposed above the upper conveying section, and the blow-out duct 24 is disposed above the lower conveying section and below the upper conveying section. The blow-out duct 23 extends along the conveying direction of the cultivation bed 4. In this embodiment, three blow-out ducts 23, 24 are provided, but it is preferable to select an appropriate number according to the width of the cultivation bed 4, and one or more blow-out ducts may be provided.

[0067] The conditioned air from the air conditioner 20 is blown downward from the main duct 21 through the air outlet 22, and most of it is sucked into the air outlet 23, flows through the air outlet 23, and is blown downward from each air outlet 23a. At this time, since the air outlet 22, the air outlet 23, and the air outlet 24 are installed separately, in addition to the conditioned air from the air conditioner 20, ambient air is sucked into the air outlet 23 and the air outlet 24. As a result, the conditioned air becomes conditioned air whose temperature and humidity have been adjusted. The air outlets 23 and 24 blow conditioned air, which is a mixture of the conditioned air and the air in the cultivation room, toward the cultivation beds.

[0068] It is desirable that the intake air volume of the blower 25 be about three times the discharge air volume of the air conditioner 20. By mixing the air blown out from the air conditioner with the surrounding air and raising the temperature of the air sent into the duct above the dew point temperature outside the duct, condensation on the surface of the duct can be prevented, and condensation water can be prevented from dripping onto the plants being grown. In addition, since the temperature inside the air duct can be made close to the temperature inside the cultivation room, condensation and its adverse effects on the plants are less likely to occur.

[0069] Most of the conditioned air blown out from the air outlet 23a hits the plants in the upper cultivation beds 4 and passes through the spaces between the cultivation beds 4 to the lower ones. At this time, most of the conditioned air passes through a space provided on the bottom surface of the conveying device 10. In this embodiment, the space provided on the bottom surface of the conveying device 10 is shared with the space of the conveying section, and most of the conditioned air passes through the bottom surface of the conveying section. This prevents moisture transpired from the plants from remaining between the leaves, making it easier to suppress tip burn. Furthermore, the leaf surface boundary layer is separated, improving carbon dioxide absorption by plants.

[0070] The conditioned air that reaches the end of the outlet duct 23 without being blown out from the outlet 23a stops at the end of the outlet duct 23, and the pressure inside the outlet duct 23 is maintained.

[0071] Most of the conditioned air blown out from the air outlets 23a, 24a hits the plants in the cultivation beds 4 on the lower level, accompanied by the airflow blowing through from the upper level, passes through the spaces between the cultivation beds 4 and the floor FL, and returns along the floor FL to the air conditioner 20. This space does not only mean that the cultivation beds 4 are arranged with a gap between them, but also means that the conditioned air can pass through the spaces between the cultivation beds 4 and reach below the cultivation beds 4.

[0072] In this way, the conditioned air blown out from each air outlet 23a, 24a not only hits the plants in the cultivation beds 4 from above, but also passes downward through the spaces between the cultivation beds 4, so that the air sufficiently hits the growing points of the plants and also reduces the temperature difference on the cultivation beds. This suppresses growth disorders such as tip burn, allowing for the efficient cultivation of high-quality plants. Furthermore, suppressing growth disorders allows for a longer growth period, resulting in plants with a higher harvest weight.

[0073] The main duct 21 extends along the upper portion of the wall 1 of the cultivation room 3 in a direction intersecting the conveying direction, preferably perpendicular thereto. The main duct 21 is provided with a plurality of air outlets 22 so as to blow out conditioned air downward or diagonally downward. As shown in FIG. 2, each air outlet 22 is disposed above or near the front of one end of the outlet duct 23, spaced apart from the inlet of the outlet duct. Similarly, an air outlet for blowing out conditioned air is also provided above or near the front of one end of the outlet duct 24.

[0074] A blower 25 for sending conditioned air into each outlet duct is provided on one end side (the left end side in FIG. 1) of each outlet duct .

[0075] A blower 26 for sending conditioned air into the outlet duct 24 is provided on the other end side (the right end side in FIG. 1) of the outlet duct 24.

[0076] The air outlet ducts 23 and 24 may be configured to allow the conditioned air to flow in the same direction, but it is preferable to have the conditioned air flow in opposite directions, as this allows air from distant locations within the cultivation room to be sent to the blower, creating air currents in opposite directions within the cultivation room, preventing air from stagnating within the cultivation room and improving the temperature uniformity of the entire system.

[0077] The air outlets 23, 24 have air outlets 23a, 24a on their undersides. When the air outlets 23, 24 are projected onto the cultivation surface, a plurality of air outlets 23a, 24a are arranged below and diagonally downward from the air outlet ducts 23, 24, up to half the height of the air outlet ducts 23, 24, so as to be symmetrical about the longitudinal axis of the air outlet ducts 23, 24. The arrangement of the air outlets 23a, 24a at a certain position in the longitudinal direction of the air outlet ducts 23, 24 is called the arrangement pattern. It is preferable that the air outlets 23a, 24a of the air outlet ducts 23, 24 be arranged in different regular arrangement patterns in the longitudinal direction. By using different regular arrangement patterns, the uniformity of the air supplied to the plants can be improved.

[0078] The opening diameter of the air outlets 23a, 24a is preferably about 10 mm to 30 mm. By setting it within this range, air will be blown out radially from the air outlets, so that the air can be sent from above the plants. Note that the wind speed is determined by the area and air volume of the air outlets 23a, 24a, so the opening area, which is the total of the air outlets, is determined by the air volume of the blower. However, the total opening area of ​​the air outlets 23a, 24a is set to 1,500 to 40,000 m. 2 Especially 4,000 to 10,000 m 2 This reduces the effect of pressure loss and allows uniform conditioned air to be supplied to the plant body in the longitudinal direction. Although the air outlets 23a and 24a are circular, this is not limiting. In the case of a non-circular air outlet, it is preferable that the opening area is approximately the same as the opening area of ​​the circular air outlets 23a and 24a.

[0079] The distance (center-to-center distance) between adjacent air outlets 23a is preferably 100 mm to 200 mm, particularly preferably 150 mm to 170 mm.

[0080] The speed of the conditioned air blown out from the air outlets 23a, 24a is preferably 0.2 to 1.0 m / s, more preferably 0.2 to 0.4 m / s. The wind speed of the conditioned air passing between the cultivation beds 4 is preferably 0.1 to 0.5 m / s, more preferably 0.1 to 0.2 m / s. By keeping the wind speed within this range, the wind speed does not place a burden on the growth of the plants, reducing damage to the plants. The wind speed is measured 50 mm above the planting holes 6 using an anemometer installed in a direction that allows the wind flow from above to be measured.

[0081] In this embodiment, the lighting 28 of the present invention is a linear light source. The light source of the lighting 28 may be a linear light source composed of tens to hundreds of LED chips forming point light sources, or a linear light source composed of COB-type LEDs integrated into a long, linear array. The linear light source may be composed of multiple bulb-shaped lighting fixtures arranged in series, or multiple rows of multiple light sources arranged in a line. The shape of the light source is not particularly limited, but a rod-like shape is preferable because it can be easily installed in a position that does not interfere with the blow-out ducts 23 and 24, and minimizing the height reduces the overall height of the device. The lighting 28 is arranged to extend from one end to the other end of the transport section. At least some of the lighting fixtures are arranged between the blow-out ducts 23 or 24.

[0082] It is preferable that part or all of the blowout ducts 23 and / or 24 be installed below the height of the lower surface of the lighting 28 and outside the orientation range of the half-value angle 2θ of the lighting 28. When installed in such a positional relationship, dead space is unlikely to be created in the vertical direction inside the device, making it easier to make effective use of the space.

[0083] The lights 28 are installed in parallel with the respective air outlet ducts 23, 24, and on the upper level side, a total of four lights 28 are provided between the air outlet ducts 23 and on the outside thereof. On the lower level side, a total of four lights 28 are provided between the air outlet ducts 24 and on the outside thereof. Such lights 28 and the positional relationship between the lights 28 and the air outlet duct 23 or 24 may be used in combination with the aforementioned plant cultivation device in which a space is provided for allowing airflow to pass below the cultivation bed.

[0084] By using LED lighting as the lighting 28, the lighting can be spaced widely apart, allowing air outlet ducts to be installed between the lighting, thereby minimizing the impact of shading caused by the air outlet ducts.

[0085] As shown in the figure, by installing a small number of lights and setting the PPF output of the lights per meter to 150 μmol / s or more, the few lights can be installed with a large gap between them, allowing each plant to be illuminated approximately evenly. The PPF output value of the lights per meter is preferably 200 μmol / s or more, even more preferably 250 μmol / s or more, particularly preferably 300 μmol / s or more, and most preferably 350 μmol / s or more. PPF stands for photosynthetic photon flux, and PPF output represents the amount of photons emitted per second from a lighting fixture. For general lighting fixtures, this corresponds to the total luminous flux (lm: lumens) of the lighting fixture, which indicates the performance of the lighting fixture itself.

[0086] Such lighting is preferably applied to the aforementioned plant cultivation device in which a space is provided between adjacent cultivation beds in the conveying direction to allow airflow to pass below the cultivation beds, and to a plant cultivation device in which an air outlet duct is provided between at least some of the lighting. By applying this to these plant cultivation devices, the distance between the lighting 28 and the cultivation bed 4 can be increased, ultimately improving temperature uniformity. Furthermore, it is possible to create a plant cultivation device in which the cultivation surface is wide in two different directions.

[0087] The PPFD on the upper surface of the cultivation bed 4 is 100 to 1000 μmol / m 2 / s. 120~500μmol / m 2 / s is more preferable, and 150 to 300 μmol / m 2 / s is more preferable. The average PPFD may be used as the PPFD. The average PPFD is the arithmetic mean of all measurement points.

[0088] PPFD is the number of photons that reach a light receiving surface per unit area per second, and in general lighting, it corresponds to illuminance (Lx: lux), which indicates the brightness at the light receiving surface. PPFD is measured by installing a photosynthetic photon flux density sensor at the measurement point and turning off surrounding lights to ensure that no light other than the lighting 28 enters.

[0089] The height from the upper surface of the cultivation bed 4 to the lighting is preferably within the range of y / tan θ to 2y / tan θ, where y is the installation interval of the lighting and 2θ is the half-value angle of the lighting. Specific heights are preferably 300 to 1500 mm, more preferably 400 to 1300 mm, even more preferably 500 to 1100 mm, and particularly preferably 600 to 900 mm. By keeping the height within the above range, it is possible to maintain lighting efficiency while achieving a uniform distribution of PPFD on the cultivation surface.

[0090] The upper limit of the distance y between the lights 28 can be calculated using the following formula (1) using the half-value angle of the light (θ) of 2θ and the height (x) from the top surface of the cultivation bed 4 to the light 28, as shown in Figure 6.

[0091]

number

[0092] In equation (1), y is the distance between the lights [cm], x is the height from the top of the cultivation bed to the light [cm], and θ is the half-value of the light's half-angle 2θ [°].

[0093] The installation interval of the lights means the distance between the centers of the lights, and the center of the lights in the longitudinal and width directions is used as the interval between rod-shaped lights. The height (x) from the top surface of the cultivation bed to the light is the height from the top surface of the cultivation bed 4 to the surface of the cover on the illuminated side of the light. When the light does not have a cover, the height (x) from the top surface of the cultivation bed to the light is the height from the top surface of the cultivation bed 4 to the light source of the light.

[0094] By setting the upper limit of the interval y between the lights 28 to the value obtained from the formula (1), the light that falls on the plant body can be made uniform.

[0095] The half-value angle 2θ of the illumination is preferably within the range of 120°±30°.

[0096] The installation range of the blowout ducts 23 and 24 is outside the light distribution range of the lighting at half-value angle 2θ. The lighting 28 is preferably an LED lighting.

[0097] The area outside the light distribution range of the half-value angle 2θ of the LED lighting is the area surrounded by lines AE, EF, FB, AD, and BC in Figure 6, and its area is expressed by the following formula (2). Lines AD and BC indicate the half-value angle 2θ of the lighting 28. The half-value angle 2θ is the angle measured based on the central axis of the light emitted from the light source, and is the angle at which the brightness is half that of the central axis of the light source.

[0098] By placing the installation range of the blow-out duct outside the light distribution range of the half-value angle 2θ of the lighting, it is possible to uniformly supply irradiated light and conditioned air to the plants, and obtain uniform light distribution, temperature distribution, and humidity distribution throughout the entire system. Furthermore, the width and depth of the system can be set longer than conventional systems. As a result of the uniform temperature and humidity distribution, it is possible to obtain homogeneous, high-quality plants.

[0099] The upper limit of the cross-sectional area (S) of the air outlet duct is calculated from the effective width (a) above the light source of the lighting, the installation interval (y) of the lighting, and the half value (θ) of the half-value angle 2θ of the lighting, using the following formula (2).

[0100] The effective width (a) above the light source of the lighting is from the outer surface of the cover on the illuminated side of the lighting to the lighting installation position. Also, if multiple blow-out ducts are installed at one location, the cross-sectional area (S) is the total cross-sectional area of ​​the multiple blow-out ducts at that location. When there is no cover on the illuminated side, the effective width (a) is the distance from the light source of the lighting to the lighting installation position.

[0101]

number

[0102] In equation (2), S is the cross-sectional area of ​​the outlet duct [cm 2 ], a: effective width above the light source of the lighting [cm], y: lighting installation interval [cm], θ: half value of the lighting half-value angle 2θ [°].

[0103] When the cross section of the air outlet duct is approximately circular, the upper limit of the diameter (R) of the air outlet duct can be calculated from the effective width (a) above the light source of the lighting and the installation interval (y) of the lighting using the following formula (3).

[0104] By making the diameter of the air outlet duct equal to or less than the value calculated by equation (3), the air outlet duct can be installed in a position where it does not block the light emitted from the lighting within the range of the half-value angle 2θ.

[0105]

number

[0106] In equation (3), R is the diameter of the air outlet duct [cm], a is the effective width above the light source of the lighting [cm], y is the distance between the lighting fixtures [cm], and θ is the half value of the lighting half-value angle 2θ [°].

[0107] The diameter of the blowout duct is preferably 10 cm or more, more preferably 15 cm or more, and even more preferably 20 cm or more. By having the diameter equal to or greater than the lower limit, it becomes easier to adjust the air volume.

[0108] When the diameter of the air outlet duct is expressed by the following mathematical formula (4), where R [cm] and L [cm] are the diameter and length, respectively, the coefficient b is preferably 0.433 or greater, more preferably 0.577 or greater, and even more preferably 0.7 or greater. By setting the diameter of the air outlet duct to a value equal to or greater than the lower limit of the length of the air outlet duct installed above the cultivation surface, it becomes easier to provide uniform airflow to the plants while maintaining the efficiency of the fan installed in the air outlet duct.

[0109]

number

[0110] In the plant cultivation device configured as described above, with the air conditioner 20 operating and the light 28 on, the cultivation bed 4 in which the seedlings are planted is placed at the entrance side (left side in Fig. 1) of the upper conveying section by hand or by a conveying machine, and is then intermittently conveyed to the right in Fig. 1 by the upper conveying device 10. The cultivation bed 4 moves intermittently by one stroke of the piston rod 13a.

[0111] The cultivation bed 4 that has moved to the right end of the upper-side conveying device 10 is transferred to the lower-side conveying device 10 by the lifting table 30, and is then intermittently moved sequentially from the right end to the left end of Figure 1 by the lower-side conveying device 10.

[0112] During this time, liquid fertilizer is supplied to each cultivation bed 4 through the liquid fertilizer supply pipe 40 and the nozzle 41.

[0113] In the plant cultivation device of the present invention, the temperature difference on each cultivation bed is within the range of ±1°C. By reducing the temperature difference between the conditioned air at the inlet and end of the air supply ducts 23 and 24, the temperature difference on the cultivation bed can be reduced to within ±1°C. In conventional plant factories, the only way to expand the shape of the cultivation surface was to expand it longitudinally. In contrast, the method of the present application makes it possible to expand it in both the longitudinal and lateral directions, thereby realizing a cultivation device with a wide cultivation surface. Furthermore, by expanding the cultivation surface in both the longitudinal and lateral directions, the proportion of the peripheral area is reduced, improving the light utilization efficiency of the lighting.

[0114] Such a plant cultivation device is preferably applied to the aforementioned plant cultivation device in which a space is provided between adjacent cultivation beds in the conveying direction to allow airflow to pass below the cultivation beds, a plant cultivation device in which an outlet duct is arranged between at least some of the lights, and a plant cultivation device in which the PPF output per 1 m of the lights is 150 μmol / s or more.

[0115] The wind speed of the conditioned air inside the air ducts 23, 24 is preferably 10 m / s to 60 m / s, particularly 30 m / s to 40 m / s, although this depends on the diameter of the air ducts 23, 24. For example, if the diameter of the air ducts 23, 24 is 0.16 m to 0.25 m, the wind speed inside the air ducts 23, 24 is 31 m / s to 38 m / s, and if the diameter of the air ducts 23, 24 is 0.14 m to 0.45 m, the wind speed is preferably 5 m / s to 60 m / s, particularly 7 m / s to 40 m / s. For example, if the length of the air duct is 10 m, the time it takes for the air to travel from the fans 25, 26 to the end of the air duct is very short, about 0.3 seconds, and therefore the temperature difference between the entrance and end of the air duct can be made extremely small.

[0116] The air volume of the fans 25 and 26 is 0.1 m 3 / s~2.5m 3 / s, preferably 0.3m 3 / s~2.2m 3 / s, more preferably 0.5m 3 / s~2.0m 3 / s, more preferably 0.7m 3 / s~1.8m 3 / s, particularly preferably 0.8 m 3 / s~1.6m 3 Depending on the variety of leafy vegetable, there may be cases where growth disorders such as tip burn do not occur even if the air volume is outside the optimum range, and in such cases, a fan with an air volume outside the optimum range may be installed. The airflow rates of the fans 25 and 26 can be considered to be approximately equal to the airflow rate that hits the vegetables, since it is considered that the entire amount of air will hit the vegetables through the air ducts 23 and 24 unless the airflow rate is excessive.

[0117] Furthermore, if the air outlet ducts 23 and 24 are located outside the range of the light distribution angle of the lighting, it is possible to reduce the effect of the air outlet ducts 23 and 24 receiving light from the lighting and increasing the temperature of the air flowing through the air outlet ducts 23 and 24. Therefore, there is almost no change in the temperature of the conditioned air from the time it enters through the fans 25 and 26, passes through the air ducts 23 and 24, and exits through the air outlets 23a and 24b. This reduces the temperature difference on the cultivation bed.

[0118] The temperature difference mentioned above can be obtained by measuring the temperature by placing temperature sensors on the cultivation bed at intervals of 5 to 10 m in the longitudinal direction of the cultivation bed and at intervals of 2 to 5 m in the transverse direction of the cultivation bed, and calculating the difference between the maximum and minimum values ​​at each level.

[0119] In the cultivation device of the present invention, the length and width of one cultivation surface are both 2 m or more. Conventional plant cultivation devices use a system that blows air from the side of the plants, so in order to provide the necessary amount of airflow to the plants without damaging them, the airflow direction must be short, and the only way to increase the cultivation surface area was to design it longer. The plant cultivation device of the present application can uniformly blow air and irradiate light, thereby improving the uniformity of temperature distribution, light intensity, and wind strength, and realizing a cultivation device with a wide cultivation surface that is long both vertically and horizontally. Furthermore, by making the cultivation surface wide both vertically and horizontally, the proportion of the peripheral area is reduced, thereby improving the light utilization efficiency of the lighting.

[0120] In the above embodiment, the transport units are installed in multiple levels, but the transport units may be arranged in one level, or in three or more levels, for example, 3 to 10 levels. By dividing the early, middle, and late stages of plant cultivation into two levels, the transportation of the cultivation beds 4 can be started and finished from the same side of the system, and the entire system can be designed compactly, so it is preferable to have an even number of levels.

[0121] In the above embodiment, the transport device is arranged in two levels, one above the other, but the number of levels is not limited to two, and may be one level, or three or more levels, for example, 3 to 10 levels. By dividing the early, middle, and late stages of plant cultivation into two levels, the start and end of transport of the cultivation beds 4 can be performed from the same side of the system, and the entire system can be designed compactly, so it is preferable to have an even number of levels.

[0122] In the above embodiment, the cultivation bed is moved from the upper level to the lower level, but the opposite may also be true.

[0123] In the above embodiment, the cultivation bed 4 is moved intermittently by the cylinder 13, but a power mechanism other than a cylinder may be used. Also, the cultivation bed 4 may be moved by other moving mechanisms such as a chain moving mechanism. The cultivation bed 4 may be moved continuously instead of intermittently.

[0124] This plant cultivation device is suitable for cultivating leafy vegetables such as Asteraceae such as frill lettuce, batavia, and salad greens, Brassicaceae such as komatsuna and bok choy, and Amaranthaceae such as spinach, as well as fruit vegetables such as Rosaceae such as strawberries and Solanaceae such as tomatoes, but is not limited to these.

[0125] In the above embodiment, the lights 28 are placed between each of the air outlet ducts 23 and 24 and on both sides of them, and a total of (N+2) lights 28 are installed, which is the number N of air outlet ducts plus 2, but more lights may also be installed.

[0126] In the above embodiment, a line light source is exemplified as the illuminator 28, but the illuminator 28 may be a point light source or a surface light source. The width of the illuminator 28 is preferably half the value of y in the above formula (1), that is, y / 2 or less. From the viewpoint of preventing the light from the illuminator 28 from being blocked by a point light source or the blowout duct 23 and resulting in inefficient use of the light from the illuminator, the width of the illuminator 28 is more preferably y / 4 or less.

[0127] The distance between the ends of the lights 28 is preferably half the value of y in the above-mentioned formula (1), i.e., y / 2 or less. The distance between the ends of the lights 28 is the distance between the ends of the two lights 28 that are closest to the discharge duct 23, with the discharge duct 23 in between. When the lights 28 are not continuous in the direction along the discharge duct 23, the distance between the ends of the lights 28 that are closest to the two lights 28 that are closest in the direction along the discharge duct 23 is also the distance between the ends of the lights 28. From the viewpoint of preventing the light from the lights 28 from being blocked by the discharge duct 23 as a point light source or the discharge duct 23 and resulting in inefficient use of light from the lights, the distance between the ends of the lights 28 is more preferably y / 4 or less. [Example]

[0128] [Basic conditions] The basic conditions were a cultivation bed tank with a slope of 1 / 80, a planting panel with six planting holes, and a nutrient solution (concentration of EC 2.0 dS / m, temperature of 20°C) supplied to the bottom of the cultivation bed tank at a flow rate of 0.6 liters per minute to cultivate frill lettuce and batavia. The cultivation area was 1300 mm wide and 1800 mm deep.

[0129] [Evaluation method] (1) Incidence of chip burn The harvested plants were peeled by hand to expose the growing point, allowing visual inspection of tip burn near the growing point. The presence or absence of tip burn was confirmed visually, and tip burn was determined to have occurred if the outer leaves of the plant or the outer leaves near the growing point turned brown or black. The incidence of tip burn was evaluated as the percentage of plants that had tip burn in at least one location per plant as a percentage of the total number of plants cultivated. (2) Harvested weight At the time of harvest, the top of the medium was cut with scissors, and any dead or discolored leaves were removed one by one, and the remaining part was then placed on a scale and weighed.

[0130] Example 1 The cultivation bed was a cultivation trough (75 mm wide, 1300 mm deep, 60 mm high), and the height from the top of the cultivation trough to the lighting was 800 mm. Two LED lights, each 1.25 m long and consuming 200 W, were used as lighting. The half-power angle 2θ of the LED lights was 120°, the PPF output was 500 μmol / s, and the average PPFD value was 200 μmol / m 2 The LED lights were spaced 800 mm apart. PPFD was measured at 10 cm intervals using a PPFD sensor (LI-COR Photon Sensor LI-190R) placed 35 mm above the top of the cultivation trough, and the average value was measured.

[0131] The wind speed of the conditioned air hitting the plants was set within the range of 0.2 m / s to 1.0 m / s, and the wind direction was set to flow uniformly from above the vegetables.Furthermore, by providing space between the cultivation gutters for the airflow to pass through, vertical wind flow was ensured. The wind speed was measured using a hot wire anemometer (Anemocheck Anemometer Model 6413, manufactured by Nippon Kanomax Co., Ltd.).

[0132] The sowing and seedling raising took 20 days, and the cultivation took 25 days, for a total cultivation period of 45 days, after which the harvest was carried out.

[0133] The incidence of tip burn and harvest weight of the plants cultivated in this manner were measured. The results are shown in Table 1.

[0134] <Comparative Example 1> Plants were cultivated and harvested in the same manner as in Example 1, except for the following changes in conditions.

[0135] The cultivation bed was a flat-type cultivation planter (300mm wide, 1300mm deep, 50mm high) with a bottom plate at the bottom of the shelf, with two rows of cultivation, and the height from the top of the cultivation trough to the lighting was 200mm. For lighting, 10 LED lights, each 1250mm long and consuming 20W of power, were used. The half-value angle 2θ of the LED lights was 120°, the PPF output was 50μmol / s, and the average PPFD was 200μmol / m 2 The LED lights were spaced 200 mm apart.

[0136] The wind speed of the conditioned air hitting the plants was set to 0.1 m / s or more, and the wind direction was set to the side of the vegetables. No space was provided between the cultivation gutters for airflow.

[0137] The sowing took place over 8 days, the seedling raising took 14 days, and the cultivation took 13 days, for a total cultivation period of 35 days, after which the harvest was carried out. The results are shown in Table 1.

[0138] [Table 1]

[0139] As shown in Table 1, it was demonstrated that the method of the present invention resulted in a harvest weight per plant that was 262 g / plant (390 g / plant - 128 g / plant) higher for frill lettuce and 214 g / plant (341 g / plant - 127 g / plant) higher for Batavia than the conventional method.

[0140] This is because the incidence of vegetable tip burn is low, allowing for longer cultivation periods than with conventional methods.

[0141] Furthermore, the daily growth weight, calculated by dividing the harvest weight by the number of cultivation days, was 8.67 g / day / plant for frill lettuce and 7.58 g / day / plant for batavia using the method of the present invention, while the growth weights using the conventional method were 3.66 g / day / plant for frill lettuce and 3.63 g / day / plant for batavia, demonstrating that the method of the present invention was superior.

[0142] <Example 2> The cultivation surface was 5m wide and 12m long, and the height from the highest point of cultivation bed 4 to the bottom of the lighting was 800mm. The cultivation surface was divided into two levels, an upper and a lower level. Nine LED lights, each 1.25m long and with a PPF output of 500μmol / s, were installed in series per level. Each level had four rows spaced 1.3m apart, and three 12m long, 30cm diameter air outlet ducts were installed. Temperature was measured daily using this cultivation device. Nine measurement positions on the cultivation surface were set up, C1 to C9. The measurement positions on the upper level were C1 to C5, and those on the lower level were C6 to C9.

[0143] Measurements were taken near the center of the cultivation surface for C1, near the four corners for C2 to C5, and near the four corners for C6 to C9. Specifically, measurements were taken at positions C1, 0 m wide, 7 m long, and 0.8 m high from the edge of the upper cultivation frame; C2, 0 m wide, 2.5 m long, and 0 m high; C3, 0 m wide, 13 m long, and 0 m high; C4, 5 m wide, 2.5 m long, and 0 m high; and C5, 13 m long, 5 m wide, and 0 m high. C6 was measured at a position 0m wide, 2.5m long and 0m high from the edge of the lower cultivation frame, C7 at a position 0m wide, 13m long and 0m high, C8 at a position 5m wide, 2.5m long and 0m high, and C9 at a position 5m wide, 13m long and 0m high.

[0144] The maximum temperature difference in the upper row was 1.6°C, the minimum was 0.4°C, and the average temperature difference was 0.97°C. The maximum temperature difference in the lower row was 1.8°C, the minimum was 0.2°C, and the average temperature difference was 1.1°C. Therefore, the temperature difference in each row was within ±0.90°C and ±1°C.

[0145] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2020-180146 filed on October 28, 2020, and Japanese Patent Application No. 2021-030534 filed on February 26, 2021, both of which are incorporated by reference in their entireties. [Explanation of symbols]

[0146] 1. Wall 2. Ceiling 3 Cultivation room 4. Growing beds 5 Cultivation board 6 planting holes 8 frames 10. Conveyor 11 Rod 12 nails 13 cylinders 18 Guide rail 20 Air conditioner 21 Main duct 23,24 Air outlet duct 30 Lift table 40 Liquid supply pipe 42 Drainage tray

Claims

1. A conveying section equipped with a conveying device for the cultivation beds is installed, A plant cultivation device provided with an air blowing means for blowing airflow toward the plants in the cultivation beds on the conveying device, The conveying unit is installed in two or more stages, This plant cultivation device is characterized in that a space is provided to allow the airflow that has blown through from the upper stage side and hits the plants in the cultivation beds on the lower stage side to pass between the cultivation beds adjacent in the conveying direction and pass through the bottom surface of the conveying device.

2. 2. The plant cultivation device according to claim 1, wherein the cultivation beds are spaced apart from one another by 40 to 500 mm.

3. The plant cultivation device of claim 1 or 2, wherein the air blowing means comprises an air conditioner that draws in air from a cultivation room in which the plant cultivation device is installed and conditioned air at a predetermined temperature range, and an outlet duct that supplies conditioned air that is a mixture of the conditioned air from the air conditioner and the air from the cultivation room and blows the conditioned air toward the cultivation bed.

4. The plant cultivation device according to claim 3, wherein the air outlet duct is installed along the conveying direction of the conveying device.

5. The plant cultivation device according to any one of claims 1 to 4, wherein the transport units are installed in multiple stages, one above the other.

6. 6. The plant cultivation device according to claim 1, wherein the longitudinal direction of the cultivation bed is a direction intersecting with the transport direction of the transport device.

7. 7. The plant cultivation device according to claim 1, wherein the cultivation bed is covered with a cultivation plate having planting holes.

8. 8. The plant cultivation device according to claim 7, wherein the planting holes are arranged in a row in the longitudinal direction of the cultivation bed.

9. 9. The plant cultivation device according to claim 1, wherein both the length and width of one cultivation surface are 2 m or more.

10. A plant cultivation method using the plant cultivation device according to any one of claims 1 to 9.

11. 11. The plant cultivation method according to claim 10, wherein the plant is a leafy vegetable such as a member of the Asteraceae family, such as frilled lettuce, batavia, or salad greens, a member of the Brassicaceae family, such as komatsuna or bok choy, or a member of the Amaranthaceae family, such as spinach, a member of the Rosaceae family, such as strawberry, or a member of the Solanaceae family, such as tomato.

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