AU2017274915A1

AU2017274915A1 - Cultivation system and cultivation method for Solanaceae seedlings

Info

Publication number: AU2017274915A1
Application number: AU2017274915A
Authority: AU
Inventors: Junya Fuse; Akio Nakaminami; De Wu
Original assignee: Mitsubishi Chemical Agri Dream Co Ltd
Current assignee: Mitsubishi Chemical Aqua Solutions Co Ltd
Priority date: 2016-06-02
Filing date: 2017-05-23
Publication date: 2018-12-20
Also published as: CN109152337B; JP2022022299A; JP7129906B2; JPWO2017208906A1; AU2017274915A8; JP7238947B2; CN109152337A; WO2017208906A1

Abstract

Provided are a cultivation system and a cultivation method whereby

Description

DESCRIPTION

Title of Invention: APPARATUS AND METHOD FOR CULTIVATING

SOLANACEOUS SEEDLINGS

Technical Field [ 0001] The present invention relates to a cultivation apparatus and a cultivation method for cultivating solanaceous seedlings. More specifically, the present invention relates to a cultivation apparatus and a cultivation method for minimizing the occurrence of plant disorders in cultivating solanaceous seedlings.

Background Art [ 0002] Traditionally, horticultural farmers have produced seedlings of various plants in-house in most cases. However, since producing seedlings of various plants requires a high level of skill, great care, and complex work, the horticultural farmers have shifted to using purchased seedlings. This is associated with recent acceleration of aging in farming population, labor shortages in farming, and corporatization and scale expansion of horticultural farming.

At the same time, there has been a growing number of specialized farmers devoted exclusively to producing horticultural crops, as well as the tendency toward saving farming labor through the use of purchased seedlings. In such circumstances, the demand for purchased seedlings has increased in recent years. In response to this, there has been an increase not only in the number of farmers specialized

10892434_1 (GHMatters) P110181.AU exclusively in producing seedlings, but also in the number of companies in the business of producing seedlings.

[ 0003] Regardless of the type of seedling producer (e.g., specialized farmers or large-scale companies), seedlings have been generally produced, for example, (A) outdoors using natural light, (B) in greenhouses using natural light, or (C) in a closed environment (see, e.g., Patent Literature 1 or 2). Production of seedlings with the methods (A) and (B) has been highly dependent on weather or climate, particularly the amount of solar radiation. For example, strong sunlight and high temperatures in summer make seedling production difficult To avoid this, seedlings of some plants need to be grown in high-altitude, cold-climate regions. In the method (B), strong sunlight in summer causes higher temperatures in greenhouses. This makes smooth production of seedlings difficult, lowers the commercialization ratios of seedlings and the operating ratios of greenhouses, and leads to increased costs of seedling production. Thus, seedling production and seedling quality are easily affected by weather or climate conditions.

[ 0004] The seedling production method (C) is a method in which, in a structure enclosed by insulating walls which do not allow passage of natural light therethrough, seedlings of high quality are produced in an artificial closed environment equipped with an air-conditioning unit, an artificial light source, a carbon dioxide fertilizer applicator, and an irrigation device. In the closed environment, various

10892434_1 (GHMatters) P110181.AU environmental conditions (e.g., quality of light, light irradiation irradiance, irradiation time, temperature, humidity, carbon dioxide concentration, amount of irrigation water, and concentration of applied fertilizer) in a space required for seedling production can be regulated at levels optimal for the growth of seedlings.

[ 0005] In cultivation of solanaceous seedlings, the production method (C) has come into wide use in recent years.

At the same time, however, more and more occurrences of various plant disorders have begun to be reported. In particular, as a plant disorder with no known cause, a socalled Intumescence has begun to be reported. Intumescence is a physiological plant disorder in which bump-like protrusions develop on surface of leaves and stems of affected plants .

[ 0006] Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2001-346450

Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2008-212078 Summary of Invention [ 0007] An object of the present invention is to solve the problems described above and provide a seedling cultivation apparatus and a seedling cultivation method by which the occurrence of plant disorder Intumesence can be minimized and stable production of high-quality solanaceous seedlings can be ensured.

10892434_1 (GHMatters) P110181.AU [ 0008] As a result of studies conducted to solve the problems described above, the present inventors have found that the occurrence of intumesence on leaves and stems of solanaceous seedlings can be minimized by using light devices that include solid-state light sources configured to emit light in a wavelength range from at least 450 nm to 660 nm on a seedling cultivation surface and produces a UV irradiance of 2.5 qW/cm² or more in a wavelength range from 295 nm to less than 320 nm. The present invention is based on this knowledge and summarized as follows.

[ 0009] [ 1] A seedling cultivation apparatus that is a cultivation apparatus for cultivating solanaceous seedlings, the cultivation apparatus comprising a light device, wherein the light device includes a solid-state light source that emits light in a wavelength range at least from

450 nm to 660 nm; and the light device irradiates UV rays of 2.5 qW/cm² or more in a wavelength range from 295 nm to less than 320 nm on a seedling cultivation surface.

[ 0010] [ 2] The seedling cultivation apparatus according to [ 1] , wherein a photosynthetic photon flux density of the light device, measured on the seedling cultivation surface, is 50 qmol/m²/sec or more.

[ 0011] [ 3] The seedling cultivation apparatus according to [ 1] or [ 2] , wherein the cultivation apparatus is installed in a

10892434_1 (GHMatters) P110181.AU closed structure, the cultivation apparatus further comprising: an air-conditioning unit configured to provide air conditioning in the closed structure; and an irrigation device configured to water the seedlings.

[ 0012] [ 4] The seedling cultivation apparatus according to [ 3] , wherein a humidity in the closed structure ranges from 30% to

100%.

[ 0013] [ 5] The seedling cultivation apparatus according to any one of [1] to [ 4] , wherein the light device produces a UV irradiance of 500 qW/cm² or less in a wavelength range from 295 nm to less than 320 nm on the seedling cultivation surface.

[ 0014] [ 6] The seedling cultivation apparatus according to any one of [1] to [ 5] , wherein a ratio I1/I2 of a UV irradiance Ii to a light irradiance I2 ranges from 0.0001 to 0.01, the UV irradiance Ii being produced on the seedling cultivation surface in a wavelength range from 295 nm to less than 320 nm by the light device, the light irradiance I2 being produced on the seedling cultivation surface in a wavelength range from 450 nm to less than 660 nm by the light device.

[ 0015] [ 7] A seedling cultivation method for cultivating solanaceous seedlings by using the seedling cultivation apparatus according to any one of [1] to [ 6] .

[ 0016] [ 8] The seedling cultivation method according to [ 7] , wherein the seedlings are seedlings of tomatoes, bell peppers, or eggplants.

10892434_1 (GHMatters) P110181.AU

Advantageous Effects of Invention [ 0017] A cultivation apparatus for cultivating solanaceous seedlings according to the present invention can minimize the occurrence of intumesence on leaves and stems of solanaceous seedlings and ensure stable production of high-guality seedlings .

Brief Description of Drawings [ 0018] Figs, la and lb are horizontal sectional views of a plant cultivation apparatus according to an embodiment. Fig. la is a sectional view taken along a line Ia-Ia in Fig.2b. Fi lb is a sectional view taken along a line Ib-Ib in Fig.2b.

Fig. 2a is a sectional view taken along a line Ila-IIa in

Fig. la. Fig. 2b is a sectional view taken along a line IlbIlb in Fig. la.

Fig. 3 is a front view of the plant growth module of multistage rack type according to the embodiment.

Fig. 4 is a sectional view taken along a line IV-IV in Fig

3.

Fig.	5	is	a	plan view of a tray	used in	the plant
cultivation	apparatus of multistage	rack type	according to the
embodiment.
Fig.	6	is	a	perspective view of	the tray	of Fig. 5.
Fig.	7	is	a	sectional view taken along a	line VII-VII in
Fig. 5.
Fig.	8	is	a	bottom view of an artificial	lighting device.
Fig.	9 is	a	sectional view taken	along a	line IX-IX in Fig

10892434_1 (GHMatters) P110181.AU .

Fig. 10 is a sectional view of a tray used in a plant cultivation apparatus of multistage rack type according to another embodiment.

Description of Embodiments [ 0019] A seedling cultivation apparatus of the present invention is for cultivating solanaceous seedlings and includes a light device. The light device includes a solidstate a light source configured to emit light in a wavelength range at least from 450 nm to 660 nm, and produces a UV irradiance of 2.5 qW/cm² or more in a wavelength range from 295 nm to less than 320 nm on a seedling cultivation surface.

In the present invention, the term light (e.g., UV light) irradiance on the seedling cultivation surface (which may hereinafter be referred to as UV irradiance on the cultivation surface or light irradiance on the cultivation surface) refers to a value obtained by measurement at the position of seedling leaves, with a light receiving surface of a spectroradiometer placed horizontally and facing upward.

The irradiation time during which the light device irradiates the seedlings with light is preferably about 8 to 20 hours per day, and particularly preferably about 12 to 18 hours per day.

[ 0020] Examples of the solanaceous plants include tomatoes, eggplants, and peppers (such as green bell peppers, bell peppers of other colors, shishito peppers, chili peppers,

10892434_1 (GHMatters) P110181.AU

- 8 habanero peppers, and jalapeno peppers). The seedling cultivation apparatus described above is suitable for use in cultivating tomatoes, green bell peppers, and eggplants, particularly tomatoes.

[ 0021] The UV irradiance on the cultivation surface, produced in a wavelength range from 295 nm to less than 320 nm by the light device used in the seedling cultivation apparatus of the present invention, is 2.5 qW/cm² or more, preferably 3.0 qW/cm² or more, more preferably 4.0 qW/cm² or more, still more preferably 6.0 qW/cm² or more, and particularly preferably 10 qW/cm² or more. When the UV irradiance on the cultivation surface in a wavelength range from 295 nm to less than 320 nm is in any of the ranges described above, it is possible to minimize the occurrence of intumesence on leaves and stems of solanaceous seedlings and ensure stable production of normal seedlings .

[ 0022] The maximum UV irradiance on the cultivation surface in a wavelength range from 295 nm to less than 320 nm is not limited to a specific value. However, to prevent ultraviolet radiation from damaging seedlings and protect workers' eyes and skin from ultraviolet radiation during cultivation operations, the maximum UV irradiance is preferably 500 qW/cm²or less, more preferably 400 qW/cm² or less, still more preferably 300 qW/cm² or less, and particularly preferably 200 qW/cm² or less.

[ 0023] The UV irradiance on the cultivation surface,

10892434_1 (GHMatters) P110181.AU produced at a wavelength of 320 nm or more (specifically in a wavelength range from 320 nm to less than 340 nm) by the light device used in the seedling cultivation apparatus of the present invention, is preferably 0.5 pW/cm² or more, more preferably 1.0 pW/cm² or more, still more preferably 1.5 pW/cm²or more, and particularly preferably 2.0 pW/cm² or more. When the UV irradiance on the cultivation surface in a wavelength range from 320 nm to less than 340 nm is in any of the ranges described above, it is possible to more effectively reduce the occurrence of intumesence on leaves and stems of seedlings.

[ 0024] The maximum UV irradiance on the cultivation surface in a wavelength range from 320 nm to less than 340 nm is not specifically defined. However, to protect workers' eyes and skin during cultivation operations, the maximum UV irradiance is preferably 300 pW/cm² or less, more preferably 250 pW/cm² or less, and still more preferably 200 pW/cm² or less.

[ 0025] The UV irradiance on the cultivation surface, produced at a wavelength of less than 295 nm (specifically in a wavelength range from 280 nm to less than 295 nm) by the light device used in the seedling cultivation apparatus of the present invention, is preferably 5.0 pW/cm² or less, more preferably 3.0 pW/cm² or less, still more preferably 1.5 pW/cm²or less, and particularly preferably 1.0 pW/cm² or less. When the UV irradiance on the cultivation surface in a wavelength range from 280 nm to less than 295 nm is in any of the ranges described above, it is possible to minimize the occurrence of

10892434_1 (GHMatters) P110181.AU

UV-related disorders, such as rolling, crinkling, and death of leaves, caused by damage done to seedlings by ultraviolet radiation .

[ 0026] The minimum UV irradiance on the cultivation surface in a wavelength range from 280 nm to less than 295 nm is not limited to a specific value. The closer the minimum UV irradiance is to zero, the more desirable it is.

[ 0027] The light irradiance on the cultivation surface, produced in a wavelength range from 450 nm to 660 nm by the light device used in the seedling cultivation apparatus of the present invention, is preferably 4000 qW/cm² or more, more preferably 4500 qW/cm² or more, still more preferably 5000 qW/cm² or more, and particularly preferably 6000 qW/cm² or more It is preferable, in the 450 nm to 660 nm wavelength range, that there be no wavelength range where the light irradiance is zero. When the light irradiance on the cultivation surface in a wavelength range from 450 nm to 660 nm is in any of the ranges described above, it is possible to minimize the occurrence of intumesence on leaves and stems of seedlings, prevent abnormalities in seedling morphogenesis, and ensure stable production of normal seedlings.

[ 0028] The maximum light irradiance on the cultivation surface in a wavelength range from 450 nm to 660 nm is not limited to a specific value. However, to minimize the occurrence of plant disorder, such as leaf scorch, the maximum light irradiance is preferably 60000 qW/cm² or less, more

10892434_1 (GHMatters) P110181.AU preferably 50000 qW/cm² or less, still more preferably 40000 qW/cm² or less, and particularly preferably 30000 qW/cm² or less .

[ 0029] A ratio K of a UV irradiance Ii on the cultivation surface produced in a wavelength range from 295 nm to less than 320 nm by the light devices used in the seedling cultivation apparatus of the present invention, to a light irradiance I2 on the cultivation surface produced in a wavelength range from 450 nm to 660 nm by the light devices used in the seedling cultivation apparatus of the present invention, preferably ranges from 1/10000 to 1/100, that is, from 0.0001 to 0.01. Having the ratio K in this range is desirable, because this makes it possible to minimize the occurrence of intumesence on leaves and stems of seedlings, prevent abnormalities in seedling morphogenesis, and ensure more reliable production of normal seedlings. The ratio K is expressed by the equation,

K = I1/I2.

[ 0030] The light device used in the seedling cultivation apparatus of the present invention includes a solid-state light source that emits light in a wavelength range from at least 450 nm to 660 nm. The solid-state light source preferably has a first emission peak wavelength in the 400 nm to 480 nm range. By having the first emission peak wavelength in the 400 nm to 480 nm range, internode elongation of seedlings can be suppressed and seedlings with short and

10892434_1 (GHMatters) P110181.AU strong hypocotyls can be grown.

[ 0031] The solid-state light source preferably has a second emission peak wavelength in the 500 nm to 620 nm range, more preferably in the 500 nm to 610 nm range, and still more preferably in the 500 nm to 600 nm range. The half-width of the second emission peak wavelength is preferably 100 nm or more, more preferably 120 nm or more, and still more preferably 140 nm or more. When the solid-state light source has the second emission peak wavelength in any of the ranges described above, it is possible to prevent abnormalities in seedling morphogenesis and ensure more efficient production of normal seedlings.

[ 0032] The seedling cultivation apparatus of the present invention may include a light device of any type, as long as at least some of them are configured to emit UV light described above. For example, all the light devices used may be light devices with the UV irradiation capability described above, or only some of the light devices used may have the UV irradiation capability and all the remaining light devices may have no UV irradiation capability. The seedling cultivation apparatus may use light devices that emit high-irradiance UV light, together with light devices that emit low-irradiance UV light or no UV light.

[ 0033] In the seedling cultivation apparatus of the present invention, the photosynthetic photon flux density measured on the seedling cultivation surface is preferably 50 qmol/m²/sec

10892434_1 (GHMatters) P110181.AU or more, more preferably 100 qmol/m²/sec or more, and still more preferably 200 qmol/m²/sec or more. Setting the photosynthetic photon flux density to at least the minimum value described above is desirable, because it is possible to ensure more efficient photosynthesis of seedlings and further reduce the occurrence of intumesence.

[ 0034] Light devices used in the seedling cultivation apparatus of the present invention are not limited to specific types. For example, fluorescent lamps, organic EL devices (which are solid-state light sources), lasers, and LEDs, can also be used as the light devices. To reduce power consumption and facilitate finer wavelength control, however, it is preferable to use LEDs.

[ 0035] It is preferable that the cultivation apparatus is installed in a closed structure, includes an air-conditioning unit that provides air conditioning in the closed structure, and includes an irrigation device that waters the seedlings.

[ 0036] The humidity in the closed structure preferably ranges from 30% to 100%, more preferably ranges from 40% to

99%, and still more preferably ranges from 40% to 95%. By setting the humidity in the closed structure in any of the ranges described above, various plant disorders that develop in solanaceous seedlings can be minimized.

[ 0037] In one embodiment of the present invention, a seedlings cultivation apparatus includes a growth module that is opened at a front surface. In the growth module, seedlings

10892434_1 (GHMatters) P110181.AU cultivation racks are arranged in multiple stages in an updown direction to form cultivation spaces.

[ 0038] A preferred embodiment of the plant cultivation apparatus will be described with reference to Figs, la to 9 and Fig. 10. As illustrated in Figs, la to 2b, a plurality (six in a illustrated example) of multistage typed plant cultivation shelves (growth modules) 3 to 8 each having a box shape are installed in a room of a closed structure 1, which is surrounded by heat-insulating wall surfaces and is completely light-shielded. The room of the structure 1 is rectangular when viewed in plan, and a door 2 is provided in one wall surface li extending in a widthwise direction.

[ 0039] In this embodiment, the three multistage typed plant cultivation shelves 3 to 5 are arranged in line with their open front surfaces facing in the same direction, and the three multistage shelf type plant cultivation apparatuses 6 to 8 are arranged in line with their open front surfaces facing in the same direction. Thus, two rows of the multistage shelf type plant cultivation apparatuses are arranged in the room with their open front surfaces opposing to each other. In the following, a direction in which the rows of the multistage shelf type plant cultivation apparatuses 3 to 5 and 6 to 8 extend (i.e., a lengthwise direction of the room) is called a

Y-direction, and the widthwise direction of the room (i.e., a direction in which the multistage typed plant cultivation shelves 3 to 5 and the multistage typed plant cultivation

10892434_1 (GHMatters) P110181.AU shelves 6 to 8 are opposed to each other) is called an Xdirection depending on cases. A space A allowing one or more workers to perform work is formed between the two rows of the multistage typed plant cultivation shelves 3 to 5 and 6 to 8. A space B having a width of about 50 to 500 mm is formed between lengthwise wall surfaces lj, lk of the room and rear surfaces of the multistage typed plant cultivation shelves 3 to 8, thus forming a path for air having passed through the multistage typed plant cultivation shelves 3 to 8.

[ 0040] Respective one ends of the rows of the multistage typed plant cultivation shelves 3 to 5 and 6 to 8 are in contact with a structure wall surface lh on the opposite side to the door 2. The respective other ends of the rows of the multistage typed plant cultivation shelves 3 to 5 and 6 to 8 are slightly apart from the wall surface li on the same side as the door 2.

[ 0041] In the case where warmed-up air flows into the space A through a gap space formed adjacent to the wall surface li on the same side as the door 2, an air baffle plate for suppressing such a flow of the warmed-up air may be disposed at an appropriate place.

[ 0042] Preferably, an air curtain is installed inside the door 2 through which the workers come in and out of the room, so that outdoor air does not enter the room when the workers come in and out of the room.

[ 0043] As illustrated in Figs. 3 and 4, each of the

10892434_1 (GHMatters) P110181.AU multistage typed plant cultivation shelves 3 to 8 is a boxshaped structure, which is opened at its front surface and which includes a pedestal 3c, right and left side panels 3a, a rear panel 3b on the rear side, and a top panel 3e defining a ceiling portion. Inside the box-shaped structure, a plurality of seedling cultivation racks 12 is arranged in multiple stages at certain intervals in the vertical direction.

[ 0044] Each of the multistage typed plant cultivation shelves 3 to 8 has a height of about 2000 mm, i.e., such a height as allowing the workers to carry out the operations on all the stages. Preferably, a width of the seedling cultivation rack 12 is set to such a value, e.g., about 1000 mm to 2000 mm, that a plurality of resin-made plug trays, each containing several tens to several hundreds cells (small pots) arrayed in a grid pattern, can be placed side by side, and that the temperature and the humidity in an upper space above each rack 12 can be adjusted to be kept constant. Furthermore, preferably, a depth of the seedling cultivation rack 12 is set to 500 mm to 1000 mm. A plurality of cell trays 40 (see Fig. lb) are substantially horizontally placed on each plant cultivation rack 12. In general, dimensions of one plug tray are about 300 mm in width and about 600 mm in length.

[ 0045] The seedling cultivation rack 12 in the lowermost stage is placed on the pedestal 3c. Levelness of the seedling cultivation rack 12 can be adjusted by an adjuster (not illustrated) that is provided on the pedestal 3c.

10892434_1 (GHMatters) P110181.AU [ 0046] An irrigation device 30, described later, is provided in each seedling cultivation rack 12.

[ 0047] Artificial lighting units 13 are disposed at respective lower surfaces of the seedling cultivation racks 12 in the second or higher stages and of the top panel 3e such that light from each artificial lighting device 13 is applied to plants growing in the plug trays 40 on the seedling cultivation rack 12 positioned just under the relevant artificial lighting device 13. In this embodiment, the artificial lighting device 13 except for one in the uppermost stage is mounted to a lower surface of an irrigation tray 31 (described later).

[ 0048] Figs. 8 and 9 illustrate details of structure of the artificial lighting device 13. Fig. 8 is a bottom view of the artificial lighting device 13, and Fig. 9 is a sectional view taken along a line IX-IX in Fig. 8. In the artificial lighting device 13, plural pairs (six in this embodiment) of sockets

13b are mounted to a lower surface of a box 13a, and both ends of a fluorescent lamp 13c are fitted to each pair of sockets

13b and 13b. A switch 13s is further attached to the lower surface of the box 13a.

[ 0049] A box 13a is a box-like body having an upper plate

13d and a lower plate 13e. The lower plate 13e serves also as a reflecting plate that reflects light from the fluorescent lamp 13c. A power supply unit 13g incorporating electric circuit components 13f, such as a stabilizer, an inverter, a

10892434_1 (GHMatters) P110181.AU constant current circuit, a constant voltage circuit, a current limiting resistance, etc., is disposed in the box 13a. In this embodiment, three power supply units 13g are arranged between the fluorescent lamps 13c, i.e., between the fluorescent lamps 13c in first and second lines, between the fluorescent lamps 13c in third and fourth lines, and between the fluorescent lamps 13c in fifth and sixth lines. The power supply units 13g are each mounted to the lower plate 13e of the box 13a. A gap of about 3 to 30 mm is left between each power supply unit 13g and the upper plate 13d of the box 13a.

In the artificial lighting device 13 of this embodiment, heat generated from the power supply unit 13g is transferred to the lower plate 13e and then dissipated from the lower plate 13e.

In other words, the generated heat is transferred to air flowing through a seedling cultivation space under the artificial lighting device 13. Heat generated from each fluorescent lamp 13c is also transferred to that flow of air.

[ 0050] Because the gap is present between the power supply unit 13g and the box upper plate 13d, an amount of heat transferred from the power supply unit 13g to the upper plate 13d is very small. Therefore, the nutrient solution flowing on the irrigation tray 31 and the rhizosphere of the plants put in the plug tray 40 are prevented from being heated by the heat from the artificial lighting devices 13.

[ 0051] As illustrated in Fig. 4, ventilation openings are formed in the rear panel 3b behind respective spaces (seedling

10892434_1 (GHMatters) P110181.AU cultivation spaces) between adjacent two of the seedling cultivation racks 12 and between the seedling cultivation rack 12 in the uppermost stage and the top panel 3e, and air fans 15 are mounted respectively to the ventilation openings.

[ 0052] By arranging the air fans 15 at a back side of each seedling cultivation space, air flows uniformly in the seedling cultivation spaces, which is preferable.

[ 0053] An air-conditioning unit 9 with the function of adjusting temperature and humidity of the air in the room and circulating the air, which has been adjusted in temperature and humidity to be matched with setting conditions, is installed in an upper portion of the room. The airconditioning unit 9 includes an air-conditioning unit body (air conditioner) 9A eguipped with a heat exchanger, and an air guide panel 10 mounted to a lower surface of the airconditioning unit body 9A. A compressor for the airconditioning unit body 9A is installed outside the structure 1 [ 0054] In this embodiment, the air-conditioning unit body 9A is positioned in a central region of the upper portion of the room when viewing the room in plan. An inlet 9a of the airconditioning unit body 9A is provided in the lower surface of the air-conditioning unit body 9A, and an aperture 10a is formed in the air guide panel 10 at a position overlapping the inlet 9a.

[ 0055] The air-conditioning unit body 9A is mounted to a ceiling It of the structure and has a structure that its

10892434_1 (GHMatters) P110181.AU lateral surfaces are exposed to the interior of the room. An air outlet 9b is provided in each of four lateral surfaces of the air-conditioning unit body 9A.

[ 0056] A portion of the air guide panel 10 around the aperture 10a is overlapped with a portion of the airconditioning unit body 9A around the inlet 9a. The aperture 10a has a size equal to or larger than that of the inlet 9a.

[ 0057] The air guide panel 10 is supported to the ceiling It with suspending attachments (not illustrated).

[ 0058] One end of the air guide panel 10 in the Y-direction is in contact with the wall surface lh. The other end of the air guide panel 10 in the Y-direction extends up to a position closer to the wall surface li than the multistage typed plant cultivation shelves 3 to 5 and 6 to 8, but it is slightly apart from the wall surface li. An upright plate lOr is erectly provided along an overall side of the air guide panel 10 at the other end, and an upper end of the upright plate lOr is in contact with the ceiling It.

[ 0059] The air guide panel 10 extends in the X-direction up to a region between the ceiling It and upper surfaces of the multistage typed plant cultivation shelves 3 to 8.

[ 0060] As illustrated in Fig. 2a, both ends of the air guide panel 10 in the X-direction are positioned vertically above the front surfaces of the multistage typed plant cultivation shelves 3 to 5 and the multistage typed plant cultivation shelves 6 to 8 on the side closer to the space A, or

10892434_1 (GHMatters) P110181.AU positioned rearward of those front surfaces, namely away from those front surfaces toward the space B. A horizontal distance L between each of both the ends of the air guide panel 10 in the X-direction and corresponding one of the front surfaces of the multistage typed plant cultivation shelves 3 to 5 and 6 to 8 may be 0 mm, but it is preferably not less than 30 mm, more preferably not less than 40 mm, even more preferably not less than 90 mm, and still even more preferably not less than 140 mm.

[ 0061] In this embodiment, spaces between both the ends of the air guide panel 10 in the X-direction and the ceiling li serve as blow-off openings 9f of the air-conditioning unit 9. When viewing the plant cultivation shelves in plan, the blowoff openings 9f may be overlapped with the front surfaces of the multistage typed plant cultivation shelves 3 to 8, but they are preferably positioned rearward of those front surfaces through the distance L.

[ 0062] In this embodiment, the inlet 9a of the airconditioning unit body 9A serves as an intake opening of the air-conditioning unit 9. When viewing the plant cultivation shelves in plan, the intake opening is positioned forward of the front surfaces of the multistage typed plant cultivation shelves 3 to 8, namely on the side closer to the space A.

[ 0063] Air circulation flows denoted by arrows in Fig. 2a are generated in the room by operating air fans 15. More specifically, air having been adjusted in temperature and

10892434_1 (GHMatters) P110181.AU humidity by the air-conditioning unit 9 is sucked into seedling cultivation spaces in stages of seedling cultivation racks 12 from the space A on the open front side of the multistage typed plant cultivation shelves 3 to 8, and is discharged to the rear side of rear panels 3b through the air fans 15. Then, the air rises through the space B between the rear side of the rear panels 3b and the structure wall surfaces, and passes through spaces C above the multistage typed plant cultivation shelves 3 to 8 to be mixed with the air blown out from the air-conditioning unit 9 and adjusted in temperature and humidity. Then, the mixed air is blown out toward the space A on the open front side of the multistage typed plant cultivation shelves s 3 to 8 again after passing between the air guide panel 10 and the multistage typed plant cultivation shelves 3 to 8.

[ 0064] Part of the air going to flow into the space A after passing between the air guide panel 10 and the multistage typed plant cultivation shelves 3 to 8 is sucked into the inlet 9a of the air-conditioning unit body 9A through the aperture 10a. After being adjusted in temperature and humidity, the sucked air is blown out from the blow-off openings 9f through the outlets 9b.

[ 0065] As illustrated in Figs, la to 2b, when the two rows of the multistage typed plant cultivation shelves 3 to 5 and the multistage typed plant cultivation shelves 6 to 8 are arrayed such that a working space is formed between the two

10892434_1 (GHMatters) P110181.AU rows, the working space serves also as the space A for air circulation, and effective circulation flows are formed.

[ 0066] When the circulation flows pass through the seedling cultivation spaces in the multistage typed plant cultivation shelves 3 to 8, water vapor evaporated from the irrigation device, culture media, the plants, etc. and the heat released from the artificial lighting devices 13 are entrained with the circulation flows. By circulating the circulation flows at the temperature and the humidity adjusted by the air-conditioning unit 9 at all times, the inside of the room can be kept as environment at the temperature and the humidity optimum for growth of the plants. A flow speed of the air flowing through the seedling cultivation spaces is preferably 0.1 m/sec or higher, more preferably 0.2 m/sec or higher, and even more preferably 0.3 m/sec or higher. If the speed of the air flow is too fast, there would be a risk that a problem occurs in growth of the plants. Therefore, the flow speed of the air is preferably 2.0 m/sec or lower.

[ 0067] While, in this embodiment, the air flow is streamed from the front surface of the seedling cultivation space to the rear-side space B of the rack through the fans 15 in a state under negative pressure, the air flow may be streamed conversely from the rear surface side to the front surface side of the rack in a state under positive pressure. However, a more uniform air flow is obtained in the seedling cultivation space by causing the air flow to stream from the

10892434_1 (GHMatters) P110181.AU front surface side to the rear surface side of the rack in a state under negative pressure.

[ 0068] In this embodiment, a rack plate of each seedling cultivation rack 12 is constituted by the irrigation tray 31 of the irrigation device (subirrigation device) 30, and irrigation is effectuated from a bottom surface of the plug tray 40 that is placed on the irrigation tray 31. An example of a structure of the irrigation device 30 will be described below with reference to Figs. 5 to 7. Fig. 5 is a plan view of the irrigation device, Fig. 6 is a perspective view thereof, and Fig. 7 is a sectional view taken along a line VII-VII in Fig. 5.

[ 0069] The irrigation device 30 includes the rectangular irrigation tray 31 having sidewalls 31a, 31b and 31c that are erected respectively at a rear side and left and right lateral sides of a lower plate 31d. A drain pit 32 in continuity with the lower plate 31d of the irrigation tray 31 is formed along a front side of the irrigation tray 31 where there is no sidewall, and aide drain opening 32a is formed at one end of the drain pit 32. The drain pit 32 and the lower plate 31d are partitioned by a dam 34, and the nutrient solution flows out into the drain pit 32 from cutouts 34a that are formed at both ends of the dam 34. Furthermore, a feed pipe 33 for supplying the nutrient solution into the irrigation tray 31 is disposed to extend along the sidewall 31a erected at the rear side of the irrigation tray 31. The nutrient solution is supplied onto

10892434_1 (GHMatters) P110181.AU the tray 31 through a plurality of small holes 33a formed in the feed pipe 33.

[ 0070] A plurality of ribs 35, each having a height of about 7 mm, is disposed on an upper surface of the lower plate 31d of the irrigation tray to extend toward the drain pit 32 parallel to each other. The plug tray 40 is placed on the ribs

35.

[ 0071] The irrigation device 30 is dimensioned, as illustrated in Fig. 4, such that when the irrigation trays 31 are placed on the seedling cultivation racks 12 of the multistage typed plant cultivation shelves 3 to 6, the drain pits 32 are positioned to project from the open front surfaces of the plant cultivation shelves 3 to 8. With the drain pits 32 projecting from the open front surfaces of the plant cultivation shelves, it is easier to collect the nutrient solution drained through the drain openings 32a of the drain pits 32 of the irrigation trays 31 placed in the seedling cultivation rack 12 of each stage, and to drain the nutrient solution to the outside of the structure 1.

[ 0072] When the nutrient solution is continuously supplied through the small holes 33a formed in the feed pipe 33 of the irrigation device 30, the nutrient solution is stemmed by the dam 34 and is pooled up to a predetermined level. While the nutrient solution is supplied from the feed pipe 33, the nutrient solution flows out to the drain pit 32 through the cutouts 34a a little by a little. A pooled state of the

10892434_1 (GHMatters) P110181.AU nutrient solution is preferably maintained in the irrigation tray 31 at a level of, e.g., about 10 to 12 mm by adjusting supply rate of the nutrient solution and drain rate of the nutrient solution of the cutouts 34a. The water is sucked up by the capillary action to the culture medium in each cell 41 through cell holes 42, which are formed in the bottom surface of each cell 41 in the cell tray 40 placed on the ribs 35, such that the culture media in all the cells 41 are brought into a water saturated state in a short time.

[ 0073] The artificial lighting device 13 is mounted to a lower surface of the lower plate 31d of the irrigation tray 31 While, in this embodiment, the upper plate 13d of the box 13a of the artificial lighting device 13 is directly contacted with the lower surface of the irrigation tray 31, a spacer or a heat insulating material may be interposed therebetween.

[ 0074] In the irrigation device 30 of this embodiment, as illustrated in Fig. 7, an upper surface of the lower plate 31d of the irrigation tray 31 is inclined toward the drain pit 32. Therefore, when the irrigation is stopped, the nutrient solution can be drained to the drain pit 32 in a short time.

In the case of inclining the upper surface of the lower plate 31d, the cell tray 40 placed on the ribs 35 can be horizontally held by gradually changing the height of each rib such that a top 35a of the rib lies horizontally.

[ 0075] Fig. 10 illustrates another example of the irrigation device used in the present invention. The same members as

10892434_1 (GHMatters) P110181.AU those in Figs. 5 to 7 are denoted by the same reference signs. In an irrigation device 30' illustrated in Fig. 10, when the cell tray 40 is placed on the lower plate 31d of the irrigation tray 31, an under tray 50 is interposed between the lower plate 31d and the plug tray 40. The under tray 50 has rigidity at such a level as being able to support the plug tray 40 including the cells 41 in each of which the culture medium is put. A plurality of small holes 51 is formed in a bottom surface of the under tray 50, and a plurality of projections 52 is formed on the rear side of the under tray 50 The projections 52 function as gap holding means for holding a gap between the lower plate 31d and the bottom surface of the cell tray 40 when the cell tray 40 is accommodated in the irrigation tray 31 together with the under tray 50.

[ 0076] Also in the irrigation device 30' of Fig. 10, when the nutrient solution is supplied from the feed pipe 33 of the irrigation device 30' and is pooled up to a predetermined level, the nutrient solution is introduced into the under tray through the small holes 51 of the under tray 50. The water is then sucked up by the capillary action to the culture medium in each cell 41 through the cell holes 42, which are formed in the bottom surface of each cell 41 in the plug tray .

[ 0077] Furthermore, in Fig. 10, the artificial lighting device 13 is similarly mounted to the lower surface of the lower plate 31d of the irrigation tray 31.

10892434_1 (GHMatters) P110181.AU [ 0078] As in the above-described embodiment, the plug tray 40 placed on the irrigation tray 31 is constituted as a unitary tray shape including several tens to several hundreds cells 41 arrayed in a grid pattern, and dimensions of one plug tray are about 300 mm in width and about 600 mm in length. However, the present invention is not limited to the abovedescribed arrangement.

[ 0079] To artificially supply carbon dioxide consumed by seedlings for photosynthesis, as illustrated in Figs, la and lb, a liguefied carbon dioxide cylinder 16 is installed outside the structure 1. The carbon dioxide is supplied from the liguefied carbon dioxide cylinder 16 such that a concentration of the carbon dioxide in the room, measured using a carbon dioxide concentration meter, is held constant.

[ 0080] By employing the above-described seedlings cultivation apparatus to cultivate seedlings, it is possible to automatically adjust environment conditions, such as a guantity of light, temperature, humidity, carbon dioxide, and water, which are suitable for the growth of the seedlings. Since all the seedlings on the seedling cultivation racks can be grown under the same environment, uniformity in guality of the cultivated seedlings can be increased.

[ 0081] In this embodiment, since the blow-off openings 9f of the air-conditioning unit 9 are positioned rearward of the front surfaces of the multistage typed plant cultivation shelves 3 to 8 through 30 mm or more, the air warmed up while

10892434_1 (GHMatters) P110181.AU passing through the multistage typed plant cultivation shelves 3 to 8 (cultivation modules) and the air cooled down by the air-conditioning unit 9 flow into the space A in a state mixed together. As a result, the air flowing into the space A becomes air having a uniform temperature, and is then taken into the multistage typed plant cultivation shelves 3 to 8.

[ 0082] If the air cooled by the air-conditioning unit 9 directly flows into the space A, air being partly cold would be taken into the multistage typed plant cultivation shelves 3 to 8 through the front surfaces. Therefore, a temperature variation would occur among the multistage typed plant cultivation shelves 3 to 8, and growth of plants would be not uniform.

[ 0083] In this embodiment, since the air-conditioning unit body 9A and the air guide panel 10 are integrated with each other, an advantageous structure is obtained in that there is no need of installing many lines of duct piping, etc.

[ 0084] In the above-described the multistage typed plant cultivation shelves, the heat generated from the artificial lighting device 13 is transferred to the box lower plate 13e, which serves also as the reflecting plate, and is further transferred from the lower plate 13e to the air flowing through the seedling cultivation space. An amount of the heat transferred from the artificial lighting device 13 to the irrigation tray 31 on the upper side is very small. Accordingly, the temperature of the nutrient solution residing

10892434_1 (GHMatters) P110181.AU on the irrigation tray 31 can be controlled to be kept within a predetermined range.

[ 0085] In the present invention, a ratio Wb/Wa of a total cooling capacity (Wb) of all the air-conditioning units 9 to a total power consumption (Wa) of all the illumination devices (i.e., the fluorescent lamps 13c in the above-described embodiment) is preferably not less than 1 and not more than 5, more preferably not less than 1 and not more than 4, even more preferably not less than 1 and not more than 3, and most preferably not less than 1 and not more than 2. By setting Wb/Wa to fall in the above-mentioned range, the environments in the closed space can be kept appropriate and constant, and environmental changes caused by turning-on/off of the airconditioning units can be held smaller. Wb/Wa cab be expressed by the following formula A on an assumption that a power consumption of one illumination device such as the fluorescent lamp is denoted by Ws, the number of the illumination devices is denoted by n, and a cooling capacity of one airconditioning unit is denoted by Wk, and the number of the installed air-conditioning units is denoted by m.

[008 6] A = Wb/Wa = (Wk x m)/(Ws x n) m: number of air-conditioning units n: number of illumination devices [ 0087] The above-described embodiment is one example of the present invention, and the present invention is not limited to

10892434_1 (GHMatters) P110181.AU the above-described embodiment. For instance, the size of the room of the closed structure and the number of the multistage typed plant cultivation shelves to be installed may be other than those described above. The air-conditioning unit body may be installed at a position other than the central region. The air-conditioning unit body may be installed two or more, but the number of the air-conditioning unit bodies is preferably as small as possible.

Examples [ 0088] Examples and Comparative Examples will now be described. In Examples and Comparative Examples described below, a seedling cultivation apparatus having the structure illustrated in Fig. la to Fig. 9 was used to cultivate tomato seedlings, with the humidity in the closed structure set in the 30% to 100% range.

[ 0089] [Measurement of UV Irradiance, Light Irradiance, and Photosynthetic Photon Flux Density]

The UV irradiance, light irradiance, and photosynthetic photon flux density on the cultivation surface in each wavelength range were measured using a spectroradiometer (product name: S-2431 model II) produced by Soma Optics Ltd.

The measurement was made at the position of seedling leaves, with a light receiving surface of the spectroradiometer placed horizontally and facing upward.

[ 0090] [ Evaluation of Seedling Growth]

By using the seedling cultivation apparatus including

10892434_1 (GHMatters) P110181.AU light devices under the conditions shown in Table 1, tomato seedlings were grown for 12 days under illumination for 16 hours per day. Evaluation of how the seedlings had been grown was made on the basis of the following criteria. The result is shown in Table 1.

VG (very good): No occurrence of intumesence is observed;

G (good): Occurrence of mild intumesence is observed in some seedlings (Protruding galls develop on leaves of some seedlings, but they are of low severity. No severe leaf yellowing or leaf drop is observed); and

NG (not good or poor): Intumesence develops in many seedlings and severe symptoms are observed (Protruding galls develop on leaves of many seedlings. Crinkling and severe yellowing of leaves and leaf drop are observed).

[ 0091] <Examples 1 to 7, Comparative Examples 1 to 4>

Tomato seedlings were cultivated on two five-stage threeshelf multistage-type plant cultivation shelves 3 (dimensions of cell trays 40: 60 cm long, 30 cm wide) installed in a completely closed space in the closed structure 1 (inside dimensions: 450 cm long, 300 cm wide, 240 cm high). An airconditioning unit with a cooling capacity of 14 kW was installed. Light devices, each having wavelength characteristics shown in Table 1 on a plant cultivation surface, were used. The result is shown in Table 1.

10892434_1 (GHMatters) P110181.AU [ 0092] [ Table 1]

was no occurrence of intumesence and seedlings were grown very successfully. In Examples 3 to 6, although there was some occurrence of intumesence, the symptoms were not severe enough to lead to leaf yellowing or leaf drop and remained mild. On the other hand, poor results were obtained in Comparative Examples 1 to 4 where the UV intensities on the cultivation surface in a wavelength range from 295 nm to less than 320 nm were lower than 2.5 qW/cm². Specifically, in Comparative Examples 1, 2, and 4, there was occurrence of intumesence, and severe plant disorders which led to leaf yellowing or leaf drop were observed. In Comparative Example 3, leaves crinkled and died due to high ultraviolet irradiance at a wavelength of less than 295 nm, in addition to the condition described above [ 0094] The above-described embodiments are examples of the present invention, and the present invention may have other embodiments .

This application claims the benefit of Japanese Patent Application No. 2016-111043 filed on June 2, 2016, which is hereby incorporated by reference herein in its entirety.

[ 0095] closed structure

3-8 multistage typed plant cultivation shelves 3a side panel 3b backside panel

3c pedestal

3e top panel

10892434_1 (GHMatters) P110181.AU air-conditioning unit

9A air-conditioning unit main body

9a inlet

9b outlet

9f blow-off opening air guide panel

10a aperture seedling cultivation rack artificial lighting device

13a box

13b socket

13c fluorescent lamp

13d upper plate

13e lower plate

13f electric circuit components 13g power supply unit

13s switch air fan liquefied carbon dioxide cylinder 30, 30' irrigation device irrigation tray

31d lower plate drain pit

32a drain opening feed pipe

33a small hole

10892434_1 (GHMatters) P110181.AU

34	dam
34a	cutout
35	rib
40	plug tray
41	cell
42	cell hole
50	under tray
51	small hole
52	proj ection

10892434_1 (GHMatters) P110181.AU

Claims

CLAIMS [ Claim 1]

A seedling cultivation apparatus that is a cultivation apparatus for cultivating solanaceous seedlings, the cultivation apparatus comprising a light device, wherein the light device includes a solid-state light source that emits light in a wavelength range at least from

450 nm to 660 nm; and the light device irradiates UV rays of 2.5 pW/cm² or more in a wavelength range from 295 nm to less than 320 nm on a seedling cultivation surface.

[ Claim 2]

The seedling cultivation apparatus according to Claim 1, wherein a photosynthetic photon flux density of the light device, measured on the seedling cultivation surface, is 50 pmol/m²/sec or more.

[ Claim 3]

The seedling cultivation apparatus according to Claim 1 or 2, wherein the cultivation apparatus is installed in a closed structure, the cultivation apparatus further comprising: an air-conditioning unit configured to provide air conditioning in the closed structure; and an irrigation device configured to water the seedlings.

[ Claim 4]

The seedling cultivation apparatus according to Claim 3,

10892434_1 (GHMatters) P110181.AU wherein a humidity in the closed structure ranges from 30% to

100%.

[ Claim 5]

The seedling cultivation apparatus according to any one of Claims 1 to 4, wherein the light device produces a UV irradiance of 500 qW/cm² or less in a wavelength range from 295 nm to less than 320 nm on the seedling cultivation surface.

[ Claim 6]

The seedling cultivation apparatus according to any one of Claims 1 to 5, wherein a ratio I1/I2 of a UV irradiance Ii to a light irradiance I2 ranges from 0.0001 to 0.01, the UV irradiance Ii being produced on the seedling cultivation surface in a wavelength range from 295 nm to less than 320 nm by the light device, the light irradiance I2 being produced on the seedling cultivation surface in a wavelength range from 450 nm to less than 660 nm by the light device.

[ Claim 7]

A seedling cultivation method for cultivating solanaceous seedlings by using the seedling cultivation apparatus according to any one of Claims 1 to 6.

[ Claim 8]

The seedling cultivation method according to Claim 7, wherein the seedlings are seedlings of tomatoes, bell peppers, or eggplants.