AU2016365988A1

AU2016365988A1 - Hydroponic culture member and hydroponic culture method

Info

Publication number: AU2016365988A1
Application number: AU2016365988A
Authority: AU
Inventors: Mitsuo INAYAMA
Original assignee: Mitsubishi Chemical Agri Dream Co Ltd
Current assignee: Mitsubishi Chemical Agri Dream Co Ltd
Priority date: 2015-12-07
Filing date: 2016-09-27
Publication date: 2018-05-31
Also published as: CN111328693A; CN108289426A; JP2017104023A; WO2017098776A1; JP6657884B2; CN111328693B; CN108289426B

Abstract

Provided are a hydroponic culture member and a hydroponic culture method whereby a leaf vegetable or a fruit vegetable with stable qualities can be cultured and the yield can be increased. The hydroponic culture member 1 comprises a culture bed tank 2, a planting panel board 3, a convex member 4, a waterproof sheet 5 and a hydrophilic sheet 6. A seedling root pot 7 is placed on the convex member 4 through a planting hole 3a of the planting panel board 3. Then, a culture solution is made to flow on the bottom face 2b of the culture bed 2 so that a plant is grown. From a venting space 8 located between a drainage channel 2e and the convex member 4, air (oxygen) is supplied to the roots.

Description

DESCRIPTION

Title of Invention: SOILLESS CULTURE APPARATUS AND SOILLESS

CULTURE METHOD

Technical Field [0001] The present invention relates to a soilless culture apparatus for plants and a soilless culture method for plants using the same, and more particularly relates to a soilless culture apparatus and a soilless culture method that appropriately supply oxygen to roots even when plants whose roots are densely grown are cultured.

Background Art [0002] Conventionally, leaf vegetables and fruit vegetables have been cultured mainly by open-field culture and greenhouse culture. However, these culture methods have problems such that vegetables cannot be stably produced due to unreasonable weather and damage from repeated culture, culture locations are limited due to weather and conditions of agricultural water, and loads on natural environment due to outflow of nutrients.

[0003] In recent years, leaf vegetables and fruit vegetables are being tried to be cultured by water culture using a nutrient solution or the like. The water culture has merits such that vegetables can be stably produced under any weather conditions, the culture locations are not limited, and the outflow of nutrients is small. PTL 1 (Japanese Patent Publication 2006-136311 A) discloses a technique of water culture using a nutrient solution, and more particularly discloses a culture method capable of stably growing crops by performing culture while a nutrient solution is supplied in an extent of wetting a water-holding sheet laid on a bottom surface of a culture bed.

[0004] In the soilless culture method, it is important to appropriately supply a nutrient solution and oxygen to roots. However, roots of plants may be grown in a dense state in a growing space for roots, and oxygen may not be sufficiently supplied. The method of improving these, PTL 2 (Japanese Patent Publication 2000-50754 A) discloses a method of adjusting a space between a water culture bet body and a lid in accordance with the growth state of roots.

[0005] However, the method of PTL 2 has problems such that the height of the lid has to be adjusted frequently in accordance with the growth state of roots, special knowledge relating to the growth of roots of plants to be cultured is required, and the height adjusting work is troublesome work.

Also, the method has a problem, in a case of plants, such as cucumbers, whose roots extend and are densely grown in a mat form, the plants are grown slowly. An area where roots are actively grown (hereinafter, also referred to as root system development layer) is mainly an area where a nutrient solution is supplied, that is, a lower zone of roots in the mat form. Hence, with the method in PTL 2, it is expected that oxygen is not sufficiently supplied to the lower zone of the mat form (root system development layer).

[0006] PTL 1: Japanese Patent Publication 2006-136311 A

PTL 2: Japanese Patent Publication 2000-50754 A [0007] As described above, in water culture using a nutrient solution, it is important to appropriately supply oxygen to the root system development layer. When plants, such as cucumbers, whose roots are actively grown and hence densely grown in a mat form in a culture bed, are cultured, it is difficult to supply oxygen by an appropriate amount to a root system development layer zone. When fruit vegetables and so forth are cultured, the culture period is long, and the roots are markedly densely grown. Hence it is difficult to supply oxygen by an appropriate amount.

Summary of Invention [0008] It is an object of the present invention to provide a soilless culture apparatus and a soilless culture method capable of culturing leaf vegetables, fruit vegetables, etc., with stable qualities and capable of increasing the harvested yield.

[0009] As the results of studies in light of the abovedescribed problems, the inventors found that, regarding roots densely grown in a mat form (hereinafter, also referred to as root system), a lower layer part of the root system being in contact with a nutrient solution (root system development layer) is markedly grown, and the roots are developed so as to push up the entire root system.

Further, the inventors found that the above-described problems can be addressed by effectively supplying oxygen to the root system development layer in which the roots are markedly grown.

[0010] The soilless culture apparatus of the present invention comprises a culture bed having a bottom surface with a gradient; and a planting panel board arranged above the culture bed and having a plurality of planting holes.

The bottom surface of the culture bed having a drain groove.

A hydrophilic sheet is arranged to cover the drain groove, and a ventilation space is formed between the hydrophilic sheet and a bottom surface of the drain groove.

[0011] The soilless culture method of the present invention comprises arranging seedling root balls through the planting holes of the soilless culture apparatus of the present invention; and causing a nutrient solution to flow on the bottom surface of the culture bed; and hence growing plants .

[0012] In one aspect of the present invention, a protruding member for placing a seedling root ball is arranged below the planting holes and above the bottom surface of the culture bed, and the hydrophilic sheet overlaps an upper surface of the protruding member. The protruding member and the culture bed may be integral, or may be separate.

[0013] In one aspect of the present invention, the protruding member is arranged to bridge the drain groove, and the ventilation space is defined below the protruding member .

[0014] In one aspect of the present invention, a communicating portion that allows water and gas to pass therethrough is present at a contact portion between the bottom surface of the culture bed and the protruding member.

[0015] In one aspect of the present invention, the protruding member has an opening.

[0016] In one aspect of the present invention, a waterproof sheet is provided on the bottom surface of the culture bed, and the hydrophilic sheet is arranged above the waterproof sheet.

Advantageous Effects of Invention [0017] In the soilless culture apparatus according to the present invention, the planting panel board having the many planting holes is arranged above the culture bed having the bottom surface with the gradient, the bottom surface of the culture bed has the drain groove, the hydrophilic sheet is arranged on the upper surface of the drain groove, and the ventilation space is defined between the hydrophilic sheet and the bottom surface of the drain groove. The nutrient solution and oxygen can be efficiently supplied to the root system development layer with the dense roots. Accordingly, by using the soilless culture apparatus according to the present invention, a plant whose roots grow fast and easily form a root system can be cultured well.

[0018] Accordingly, with the present invention, a soilless culture apparatus and a soilless culture method capable of culturing leaf vegetables, fruit vegetables, etc., with stable qualities and capable of increasing the harvested yield are provided.

[0019] The soilless culture apparatus according to the present invention preferably includes the waterproof sheet on the bottom surface of the culture bed. By providing the waterproof sheet on the bottom surface of the culture bed, the nutrient solution can be prevented from leaking from the culture bed. Also, even when a plurality of culture beds are connected and used for culture, the nutrient solution can be prevented from leaking from the connection portion. Brief Description of Drawings [0020] [Fig. 1] Fig. 1 is a cross-sectional perspective view of a soilless culture apparatus according to an embodiment.

[Fig. 2] Fig. 2 is a cross-sectional view of the soilless culture apparatus according to the embodiment.

[Fig. 3] Fig. 3 is a perspective view of a culture bed [Fig. 4] Fig. 4 is a perspective view of a protruding member .

[Fig. 5] Fig. 5 is a plan view of a culture system according to the embodiment.

Description of Embodiments [0021] The present invention is described in further detail below; however, the present invention is not limited to the following embodiment.

[0022] Fig. 1 is a cross-sectional perspective view illustrating a soilless culture apparatus according to an embodiment, and Fig. 2 is an enlarged cross-sectional view of part of Fig. 1. Fig. 2 also illustrates roots extending from a seedling root ball and grown densely. Figs. 3 and 4 are perspective views of a culture bed and a protruding member .

[0023] A soilless culture apparatus 1 includes a culture bed 2 and a planting panel board 3 made of expanded plastic such as expanded polystyrene, a protruding member 4, a waterproof sheet 5, and a hydrophilic sheet 6.

[0024] As illustrated in Fig. 3, the culture bed 2 has a long box shape extending in one direction and having an upper surface being open, and has a U-like cross-sectional shape including a pair of long side walls 2a, 2a and a base portion 2b.

[0025]

Crossing-angle edge portions between upper end surfaces and inner side surfaces of the long side walls 2a,

2a are cut step portions 2d, and side edges of the planting panel board 3 are engaged with the step portions 2d.

[0026] A drain groove 2e is provided in an upper surface of the base portion 2b (a bottom surface of the culture bed

2), and extends in a longitudinal direction of the culture bed 2 .

[0027] The upper surface of the base portion 2b (the bottom surface of the culture bed 2) of the culture bed 2 according to this embodiment does not have a gradient, and the body of the culture bed 2 is disposed with a gradient.

However, the upper surface of the base portion 2b (the bottom surface of the culture bed 2) may have a gradient, and the culture bed 2 may be disposed horizontally.

[0028] In this embodiment, only one drain groove 2e is provided at the center in a width direction of the base portion 2b. However, the number of drain grooves 2e may be two or larger, and may be appropriately set in accordance with the required supply amounts of a nutrient solution and oxygen. The number of drain grooves 2e is preferably one for every 100 to 700 mm, more preferably one for every 200 to 600 mm, and further preferably one for every 300 to 500 mm in a width W₂ direction of the culture bed 2.

[0029] A depth H3 of the drain groove 2e can be appropriately set in accordance with the amount of the nutrient solution to be supplied and the gradient of the culture bed, as long as a depth sufficient for a flow of a nutrient solution L and a space sufficient for supplying oxygen in a humid atmosphere can be ensured. Regarding the productivity and the cost of members, the depth H3 of the drain groove 2e is preferably in a range from 10 to 50 mm, more preferably in a range from 15 to 40 mm, and further preferably in a range from 15 to 35 mm.

[0030] A width Wi of the drain groove 2e can be appropriately set in accordance with the amount of the nutrient solution to be supplied and the gradient of the culture bed, as long as a depth sufficient for a flow of the nutrient solution L and a space sufficient for supplying oxygen in a humid atmosphere can be ensured. Regarding the productivity and the cost of members, the width Wi of the drain groove 2e is preferably in a range from 30 to 200 mm, more preferably in a range from 40 to 180 mm, and further preferably in a range from 50 to 150 mm.

[0031] The lengths of the culture bed 2 and the planting panel board 3 are, for example, in a range from about 1000 to 3000 mm; however, it is not limited thereto.

[0032] The planting panel board 3 has a plurality of planting holes 3a provided at intervals in the longitudinal direction. The planting holes 3a are located above the protruding member 4. In the illustrated embodiment, onlyone drain groove 2e is provided, and one row of the planting holes 3a is provided; however, a plurality of drain grooves

2e may be provided, and a plurality of rows of the planting holes 3a may be provided. Further, the position of the drain groove 2e and the positions of the planting holes 3a do not have to be in the same line.

[0033] The waterproof sheet 5 is provided to cover the upper end surfaces and inner side surfaces of the long side walls 2a, 2a, the upper surface of the base portion 2b, and a bottom surface and both side surfaces of the drain groove

2e of the culture bed 2.

[0034] The protruding member 4 is provided to bridge the drain groove 2e. In this embodiment, the protruding member has a body portion 4c having a substantially semicircular cylindrical shape, and flange portions 4a protruding outward from both side edges in the longitudinal direction of the body portion 4c. The body portion 4c has a plurality of openings 4b provided at intervals in the longitudinal direction at positions near the flange portions 4a.

[0035] The shape of the body portion 4c is not limited to the semicircular cylindrical shape, and may have a semiellipsoidal cross-sectional shape or a downward-facing angular C-like cross-sectional shape. The shapes of the openings 4b each are not particularly limited as long as the shape allows the nutrient solution and the air to pass therethrough, and may have, for example, a circular shape, an ellipsoidal shape, or a slit shape.

[0036] The positions of the openings 4b are not particularly limited; however, may be preferably set at a height in a range from 5 to 50 mm, more particularly in a range from 5 to 40 mm, and further particularly in a range from 5 to 30 mm from the flange portions 4a.

[0037] After the waterproof sheet 5 is laid, the protruding member 4 is arranged so that the body portion 4c bridges the drain groove 2e and the flange portions 4a, 4a extend along edge portions of the drain groove 2e.

Communicating portions 4d through which liquid and the air pass are formed between the flange portions 4a and the waterproof sheet 5 below the flange portions 4a, due to a bending of the protruding member 4 and a wrinkle of the waterproof sheet 5. To increase the height of the communicating portions 4d, spacers may be arranged, or protrusions may be provided on lower surfaces of the flange portions 4a. A space surrounded by the protruding member 4 and the drain groove 2e is defined as a ventilation space 8 [0038] The height of the protruding member 4 is not particularly limited, and may be appropriately set in accordance with the height of a space S between the culture bed 2 and the planting panel board 3 and the plants to be cultured. However, a height Hi from the top of the protruding member 4 to a lower surface of the planting panel board 3 is preferably in a range from 20 to 100 mm, and more preferably in a range from 20 to 80 mm.

[0039] A height H2 between the base portion 2b of the culture bed 2 and the planting panel board 3 may be appropriately set in accordance with the type of plants to be cultured and the culture period. With regard to the productivity and the cost of materials, the height H2 is preferably in a range from about 50 to 150 mm.

[0040] The hydrophilic sheet 6 is provided to cover the upper end surfaces and inner side surfaces of the long side walls 2a, and the upper surface of the base portion 2b other than the drain groove 2e of the culture bed 2, as well as the upper surface of the protruding member 4. The material of the hydrophilic sheet 6 is not particularly limited as long as the material allows the air to transmit therethrough, can draw up the solution by capillary action, and inhibits roots from passing therethrough. For example, the material may be non-woven fabric, paper, or cloth. The hydrophilic sheet may be one commercially available as a root-shielding sheet.

[0041] A plurality of the soilless culture apparatuses 1 thus configured are joined with one another, and define a culture bed row 10 (Fig. 5) with a length in a range from 10 to 100 m. The waterproof sheet 5 is continuously laid over the respective culture beds 2 . Accordingly, water is prevented from leaking from the joint surfaces between the culture beds 2.

[0042] A seedling root ball 7 is placed on the protruding member 4 through each of the planting holes 3a of the planting panel board 3 provided to cover each of the culture beds 2, a nutrient solution is caused to flow on the bottom surface 2b of the culture bed 2, and hence plants are grown.

Accordingly, roots 7r (Fig. 2) extend from the seedling root ball 7 into the growing space S surrounded by the long side walls 2a, 2a, the base portion 2b, and the planting panel board 3.

[0043] Since the protruding member 4 is used, the growing space S between the culture bed 2 and the planting panel board 3 can be an appropriate space. Also, since the seedling root ball 7 is not exposed to the flow of the nutrient solution, a culture medium of the seedling root ball 7 is not broken or does not flow out.

[0044] Since the protruding member 4, the drain groove 2e, and the hydrophilic sheet 6 are arranged, the flow of the nutrient solution flowing on the bottom surface of the culture bed 2 is not disturbed by the growth of the roots of the plants to be cultured, or the nutrient solution is not retained. That is, by causing the retained nutrient solution to flow into the drain groove 2e, the nutrient solution is not retained, the roots of the plants to be cultured are not immersed in the nutrient solution and hence insufficiency in oxygen is prevented, and the nutrient solution can be supplied to the roots of the plants by an appropriate amount.

[0045] Oxygen (air) in the drain groove 2e and the ventilation space 8 can be efficiently supplied to the root system development layer R of the roots densely grown in the root growing space S from the ventilation space 8 through the communicating portions 4d, the openings 4b, and the hydrophilic sheet 6.

[0046] With the soilless culture method according to the present invention, roots having two different forms and functions can be generated, the roots including roots in the water grown in water and roots in the humid air held in a humid atmosphere and having many hair roots. The roots in the water absorb nutrients and water mainly from a nutrient solution, and the roots in the humid air directly absorb oxygen mainly from a humid atmosphere.

[0047] The root system of plants grown by the soilless culture method according to the present invention may be a root system having a zone mainly occupied by roots in the water, a zone mainly occupied by roots in the humid air, and a zone with roots in the water and roots in the humid air mixed. Further, by efficiently supplying oxygen to the zone with roots in the water and roots in the humid air mixed and the zone mainly occupied by roots in the water, insufficiency in dissolved oxygen can be prevented even when the roots are densely grown, and the harvested yield can be increased.

[0048] The soilless culture apparatus according to the present invention is particularly suitable for a Nutrient Film Technique (hereinafter, also referred to as NFT) in which the depth of water is small and oxygen is easily supplied to roots.

[0049] The present invention can be used preferably for culture of fruit vegetables in which many roots are grown, more preferably for culture of plants of Cucurbitaceae, and further preferably for culture of cucumbers.

[0050] Fig. 5 is a plan view of a hydroponic culture system according to the embodiment of the present invention.

[0051] In Fig. 5, a plurality of culture beds 2 are connected in series in a greenhouse to form a culture bed row 10. A plurality of culture bed rows 10 are arrayed in a plurality of rows (in the figure, four rows) to form a culture bed group 20. A plurality of culture bed groups 20 are arranged in parallel. In one culture bed row 10, the plurality of culture beds 2 are arrayed in series, and the waterproof sheet 5 is disposed over the respective culture beds 2. Accordingly, water is prevented from leaking from the joint surfaces between the culture beds 2 . The number of culture beds 2 forming one culture bed row 10 is in a range from about 5 to 100; however, it is not limited thereto .

[0052] Each culture bed row 10 is disposed with a gradient in a range from about 1/80 to 1/200 to have a flow gradient from one end portion to the other end portion in the longitudinal direction. One sub-tank 33 is provided for one culture bed group 20.

[0053] The hydroponic culture system includes a main tank that stores a nutrient solution. The main tank 26 is supplied with liquid nutrients and water from pipes 24, 25 having supply control valves 24a, 25a, and a nutrient solution with a predetermined density is prepared. The nutrient solution with the predetermined density prepared in the main tank 26 is distributed and supplied to each subtank 33 via a pump 27, a pipe 28, a three-way valve 29, a flowmeter 30, and a ball tap 31. The three-way valve 29 is connected to a water supply pipe 32. By switching the three-way valve 29, water from the pipe 32 can be supplied to the sub-tank 33.

[0054] The solution in the sub-tank 33 is supplied to each culture bed row 10 via a pump 34, a pipe 35, and a valve 36.

[0055] The nutrient solution prepared in the main tank 26 is supplied to and stored in the sub-tank 33, and hence the nutrient solution with the uniform density prepared in the main tank 26 can be constantly supplied to each culture bed row 10.

[0056] In Fig. 5, the nutrient solution used by one culture bed group 20 is returned to the sub-tank 33 of the culture bed group 20 via a pipe 37 and the nutrient solution is circulated. The sub-tank 33 is additionally supplied with the nutrient solution from the main tank 26 or the water from the pipe 32 by the ball tap 31, and the liquid level of the nutrient solution in the sub-tank 33 is maintained to be constant.

[0057] As illustrated in Fig. 5, since the sub-tank 33 is provided for each culture bet tank group 20, the sub-tank 33 can manage the nutrient solution for culture by a relatively small amount. When harvesting is completed, it is preferable to discard the nutrient solution used in one culture bed group 20, and start culture with a new nutrient solution .

[0058] Accordingly, vegetables to be cultured in the next period can be stably cultured without influences of secretion (such as organic acid) flowing out from roots or dropping of epidermal cells of the roots flowing into the nutrient solution by culture in the previous period.

[0059] In Fig. 5, steps can be individually advanced on the culture bed group 20 basis, such that while culturing is continued in part of the culture bed groups 20, cleaning is performed in another culture bed group 20 (cleaning after harvesting is completed).

[0060] Even when disease germs appear in one culture bed group 20, infection of the disease germs to another culture bet tank group 20 can be prevented. That is, since the nutrient solution is not returned to the main tank 26, pollution is stopped in the closed circuit (culture bed group 20) through which the nutrient solution is circulated.

[0061] In a later culture period for leaf vegetables and fruit vegetables cultured in each culture bed group 20, by switching from supply with the nutrient solution to supply with the water, the nutrient density of the nutrient solution that is circulated between the sub-tank 33 and the culture bed row 10 can be decreased. Consequently, in the later culture period, the amount of nitric acid in a plant body can be gradually decreased, and leaf vegetables and fruit vegetables can be harvested in a state in which the amount of nitric acid is reduced.

[0062] When taken into a human body, nitric acid in a plant body is bound to amide nitrogen and nitrosamine is generated. By decreasing the nutrient density of the nutrient solution in the later culture period, the density of nitric acid in a plant body can be decreased. Also, in the later culture period, by decreasing the densities of nitrogen, phosphoric acid, and potassium in the used nutrient solution, loads on environment can be markedly decreased when the nutrient solution is discarded after harvesting is completed.

EXAMPLES [0063] [EXAMPLE 1]

Five culture beds 2 illustrated in Figs. 1 to 4 were arrayed in series to form a culture bed row 10 having a length of 10 m. Four culture bed rows 10 were disposed in parallel to form a culture bed group 20. One set of culture bed groups 20 was disposed, and hence the culture system illustrated in Fig. 5 was formed. By using the system, cucumbers were cultured under the following conditions. A nutrient solution with a nutrient solution concentration of

EC 2.0 dS/m at a nutrient temperature of 20°C was used. The results of harvesting were shown in Table 1.

[0064] Cultivation area: 60 m²

Number of seedlings: 80 (0.75 m²/seedling)

of culture bed
Hi:	50	mm
H₂:	100	mm
H₃:	20	mm
Wi :	100	mm
W₂:	400	mm

Gradient of culture bed: 1/100

Supply amount of nutrient solution: 10 litters/min [0065] [Table 1]

Seeding	Planting	Harvesting period	Yield (t/10 ares)
Mid-Au gust	Early September	October to December	15
Mid-January	Early February	March to June	20
Mid-June	Early July	August to September	10

[0066] Regarding the results in Table 1, by culturing cucumbers by using the soilless culture apparatus according to the present invention, cucumbers could be harvested by about 45 t as the harvested yield per 10 ares for one year.

As compared with the average harvested yield of 20 to 25 t/10 ares of cucumbers by soil culture, culture using the soilless culture apparatus according to the present invention provided a large harvested yield.

[0067] While the present invention has been described in detail by using the specific aspect, it is obvious to persons skilled in the art to be able to make various modifications without departing from the intension and scope of the present invention.

This application is based on Japanese Patent

Application No. 2015-238746 filed December 7, 2015, which is hereby incorporated by reference herein in its entirety.

Reference Signs List [0068] 1 soilless culture apparatus culture bed bottom surface drain groove planting panel board planting hole protruding member opening communicating portion waterproof sheet hydrophilic sheet seedling root ball ventilation space culture bed row culture bed group main tank three-way valve flowmeter ball tap

Claims

CLAIMS [Claim 1]

A soilless culture apparatus comprising:

a culture bed having a bottom surface with a gradient;

and a planting panel board arranged above the culture bed and having a plurality of planting holes, the bottom surface of the culture bed having a drain groove, wherein a hydrophilic sheet is arranged to cover the drain groove, and wherein a ventilation space is formed between the hydrophilic sheet and a bottom surface of the drain groove.
[Claim 2]

The soilless culture apparatus according to claim 1, wherein a protruding member for placing a seedling root ball is arranged below the planting holes and above the bottom surface of the culture bed, and the hydrophilic sheet overlaps an upper surface of the protruding member.
[Claim 3]

The soilless culture apparatus according to claim 2, wherein the protruding member is arranged to bridge the drain groove, and wherein the ventilation space is defined below the protruding member.
[Claim 4]

The soilless culture apparatus according to claim 2 or

3, wherein a communicating portion that allows water and gas to pass therethrough is present at a contact portion between the bottom surface of the culture bed and the protruding member .
[Claim 5]

The soilless culture apparatus according to any one of claims 2 to 4, wherein the protruding member has an opening.
[Claim 6]

The soilless culture apparatus according to any one of claims 1 to 5, wherein a waterproof sheet is provided on the bottom surface of the culture bed, and the hydrophilic sheet is arranged above the waterproof sheet.
[Claim 7]

A soilless culture method comprising: arranging seedling root balls through the planting holes of the soilless culture apparatus according to any one of claims 1 to 6; and causing a nutrient solution to flow on the bottom surface of the culture bed; and hence growing plants.
[Claim 8]

The soilless culture method according to claim 7, wherein the plants are plants of cucurbitaceae.

1/5 £ 2e

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