Hydroponic cultivation device

Abstract

To provide a hydroponic cultivation device that is favorably applicable to root vegetables and achieves high productivity.SOLUTION: A hydroponic cultivation device includes a first unit 100 for allowing the roots of seedlings to grow. The first unit 100 includes: a plurality of nutrient solution tanks 111, 112, 113, 114, 115, which is lined up in one direction with a nutrient solution disposed inside; and a support part that supports a seedbed 10 disposed above the nutrient solution tanks. The distance between the liquid surface of the nutrient solution disposed in each of the nutrient solution tanks and the support part gradually increases from one end to the other end in one direction.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a hydroponic cultivation device.

Background Art

[0002] In agriculture, which has various problems, hydroponic cultivation using liquid fertilizer has attracted attention. However, regarding the hydroponic cultivation of root vegetables, it has hardly been put into practical use yet and has not reached full commercialization.

[0003] Patent Document 1 describes a hydroponic cultivation device applicable to root vegetables. This device includes a nutrient solution storage container and a lid member fixed so as to face the liquid surface of the nutrient solution in the nutrient solution storage container at a certain interval. Only the tip of the main root of the plant supported by the lid member is immersed in the nutrient solution in the nutrient solution storage container, so that the roots of the root vegetable seedlings can be extended and then thickened. Therefore, root vegetables with long and thick roots can be cultivated while being hydroponically cultivated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The hydroponic cultivation device described in Patent Document 1 is by the applicant and is very excellent in that it can be applied to root vegetables. The inventors found points for improvement necessary for more efficiently producing root vegetables with respect to this hydroponic cultivation device and completed the present invention.

[0006] An object of the present invention is to provide a hydroponic cultivation device that can be favorably applied to root vegetables and has high productivity.

Means for Solving the Problems

[0007] The first aspect of the present invention is a hydroponic cultivation device including a root elongation part for growing the roots of seedlings. The root elongation part has a plurality of nutrient solution tanks arranged side by side in one direction with a nutrient solution disposed therein, and a support part for supporting a seedling bed disposed above the nutrient solution tanks. The distance between the water surface of the nutrient solution disposed in each of the nutrient solution tanks and the support part gradually increases from one side to the other side in one direction.

Advantages of the Invention

[0008] The hydroponic cultivation device according to the present invention can be favorably applied to root vegetables and has high productivity.

Brief Description of the Drawings

[0009]

Figure 1

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Modes for Carrying Out the Invention

[0010] Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 8. FIG. 1 is a block diagram of the hydroponic cultivation device 1 according to the present embodiment. The hydroponic cultivation device 1 includes a first unit (root elongation unit) 100 for growing the roots of seedlings to a sufficient length, and a second unit 200 for thickening the grown roots.

[0011] FIG. 2 is a perspective view showing the first unit 100. The first unit 100 includes a frame (support part) 110 and a plurality of nutrient solution tanks installed on the frame 110. A plurality of seedling beds 10 are installed on the upper part of the frame 110, and illumination light for promoting growth is irradiated from illumination (not shown). There is no particular limitation on the specific configuration of the illumination, and a white light source, a combination of a red LED and a blue LED, etc. can be appropriately selected and used.

[0012] FIG. 3 is a schematic diagram showing the configuration of the first unit. The frame 110 is divided into a plurality of sections in one direction (in the present embodiment, the longitudinal direction), and nutrient solution tanks 111, 112, 113, 114, 115 extending across the width direction of the frame are arranged in each section. A nutrient solution containing components necessary for the growth of root vegetables to be grown and water is arranged in each nutrient solution tank, and the upper part is open. The nutrient solution can be obtained, for example, by diluting liquid fertilizer with water. The number of sections in the present embodiment is 5, but this is not essential and can be any desired number.

[0013] In the present embodiment, the five nutrient solution tanks are generally of the same size and generally contain the same amount of nutrient solution, but the installation heights of the nutrient solution tanks are different. More specifically, the nutrient solution tank 111 located at one end in the direction in which the five sections are arranged is installed at the highest position, and the installation position gradually decreases toward the nutrient solution tank 115 located at the other end, and the nutrient solution tank 115 is installed at the lowest position. As a result, the water surface of the nutrient solution arranged in each nutrient solution tank is the highest in the nutrient solution tank 111 and gradually decreases in a stepped manner toward the nutrient solution tank 115. Each nutrient solution tank is connected to different nutrient solution tanks 121, 122, 123, 124, and 125 respectively, and the nutrient solution is circulated by the pump P. Fresh nutrient solution is periodically supplied to each nutrient solution tank, so that the nutrient solution in the nutrient solution tanks 111, 112, 113, 114, and 115 is constantly updated with little change in the water surface position, and the components necessary for the growth of the crops are always maintained at a predetermined amount.

[0014] The seedbed 10 has planar dimensions that can be arranged within one section. In the present embodiment, the planar shape of the seedbed 10 is a rectangle with the long side being approximately the same length as the width of the frame 110 and the short side being approximately the same length as the dimension of each section in the longitudinal direction of the frame 110.

[0015] The process up to the first unit 100 in the cultivation of root vegetables using the hydroponic cultivation device 1 will be described. First, the seedlings of root vegetables are initially grown to a degree that they can be installed on the seedbed 10. There is no particular limitation on the method of cultivation. For example, seeds are sown on a sponge cut to a predetermined size, floated in water to germinate, and the roots are extended to a length that can be installed in the first unit (for example, 50 mm or more). At this time, if the water in which it is floated contains abundant nutrients, the roots are likely to branch. Therefore, it is preferable to use water that does not contain nutrients so that the roots can easily grow in a single state.

[0016] When the roots of the seedlings reach the desired length, the seedlings are installed on the seedbed 10, and the seedbed 10 is installed on the frame 110 located above the nutrient solution tank 111 where the water surface of the nutrient solution is at the highest position. The distance between the seedlings installed on the seedbed 10 and the nutrient solution tank 111 is set such that only the tip of the roots of the seedlings is immersed in the nutrient solution by about several centimeters. In this state, in the first section S1 where the nutrient solution tank 111 is installed, the seedlings are grown. Since only the tip of the roots of the seedlings is immersed in the nutrient solution, the roots increase only in length without branching.

[0017] When the roots of the seedlings reach a predetermined length, the seedling tray 10 is moved to the upper part of the nutrient solution tank 112 adjacent to the nutrient solution tank 111. When moving, it may be slid directly on the frame, or the seedling tray 10 may be lifted upward to avoid interference between the wall surface of the nutrient solution tank 111 and the roots. In parallel, a new seedling tray 10 may be installed in the empty first section S1. In this state, in the second section S2 where the nutrient solution tank 112 is installed, the seedlings are continuously grown. Since the water surface of the nutrient solution tank 112 is at a lower position than the water surface of the nutrient solution tank 111, in the second section S2 as well, only the tip of the root of the seedling is immersed in the nutrient solution. Therefore, the root increases only in its length without branching.

[0018] In this way, by moving the seedling tray 10 to an adjacent section where the water surface of the nutrient solution is lower every time the seedlings are grown for a predetermined period, seedlings with roots that have grown to a length where generally only one root can be installed in the second unit 200 can be easily grown. By sequentially installing new seedling trays 10 in the empty sections, it becomes possible to continuously and efficiently grow the seedlings to be installed in the second unit 200.

[0019] In the first unit 100, the composition and concentration of the nutrients in the nutrient solution may be different for each section. Also, when using a nutrient solution of the same composition in a plurality of sections, one nutrient solution tank may be connected to two or more nutrient solution tanks. That is, the nutrient solution tank and the nutrient solution tank do not necessarily have to be provided in a one-to-one relationship.

[0020] In this embodiment, when the seedlings are grown for a predetermined period in the fifth section S5 where the water surface position of the nutrient solution is the lowest, the seedlings are in a state where they can be installed in the second unit 200, and the growth in the first unit 100 is completed. Subsequently, the second unit 200 will be described.

[0021] FIG. 4 is a perspective view showing the second unit 200. FIG. 5 is a schematic diagram showing the configuration of the second unit 200. As shown in FIGS. 4 and 5, the second unit 200 includes a nutrient solution tank 210 extending in one direction and a support rail 220 disposed above the nutrient solution tank 210.

[0022] The nutrient solution tank 210 is a half-pipe-shaped member that can store nutrient solution inside. As long as this condition is satisfied, a rain gutter for general construction or the like can also be used. The stored nutrient solution may be supplied manually, but it can also be connected to a nutrient solution tank by piping as in the first unit 100, and automatic circulation management using a pump, a filter, etc. can be performed.

[0023] The support rail 220 according to this embodiment is a pair of rails extending substantially parallel to the nutrient solution tank 210. A plurality of rollers 221 are disposed on the upper side of the support rail 220.

[0024] As shown in FIGS. 4 and 5, a seedbed 20 is disposed on the support rail 220. The seedbed 20 has a pair of plates 21 and a stopper 25 disposed on the plate 21. The plate 21 is formed of metal or the like and has a rigidity such that it can maintain a substantially flat state even when a target crop that has grown sufficiently while being spanned over the support rail 220 is supported. The plate 21 of this embodiment is composed of a first plate 21a and a second plate 21b having the same shape and size, and when they are brought close to each other so that the recesses 22 formed at the peripheries abut against each other, a desired number of holes penetrating in the thickness direction of the plate 21 are formed by the recesses 22 of each other.

[0025] The stopper 25 according to this embodiment is configured using two sponges 26 having irregularities on one surface as shown in FIG. 7(a). The sponge 26 is square in plan view and has a first cut 27a reaching from one side of the periphery to the center in plan view and a plurality of second cuts 27b extending with a length that does not reach from the center in plan view to the periphery as shown in FIG. 7(b). When the two sponges 26 are overlapped such that the irregular surfaces face each other, the extending directions of the respective first cuts 27a are different, and the centers in plan view substantially coincide, the stopper 25 is completed.

[0026] Regarding the process related to the second unit 200 in the cultivation of root vegetables using the hydroponic cultivation device 1, an explanation will be given. The seedlings that have grown in the first unit 100 and have roots of sufficient length are removed from the seedbed 10 and placed on the seedbed 20. When installing, pass the boundary part between the root and the stem through the first cut 27a of one sponge 26 and position the seedling near the center in plan view of the sponge. Further, when adjusting by passing the boundary part between the root and the stem through the first cut 27a of another sponge 26 so that the two sponges form the stopper 25, the stopper 25 is attached to the seedling. When placing the stopper 25 on the plate 21 while passing the roots of the seedlings through the holes formed in the plate 21, the seedlings are installed on the seedbed 20.

[0027] When the operator arranges the seedbed 20 to be hung on the support rail 220, only the tip of the root of the seedling (for example, about several centimeters from the tip) is immersed in the nutrient solution in the nutrient solution tank 210. Further, when installing the seedbed 20, if the seedbed 20 already installed is pushed by the plate 21 to be installed next, the seedbed 20 slides on the roller 221 and moves. Therefore, the operator can easily install a plurality of seedbeds 20 on the support rail 220 without large movement. Note that the timing of installing the seedlings on the seedbed can be set as appropriate. That is, as described above, it may be before arranging the seedbed 20 on the support rail 220, or the seedlings may be installed after only the plate 21 is arranged on the support rail 220.

[0028] After installing the seedbed 20, light for growth is irradiated from lighting (not shown) etc., and the seedlings are grown for a predetermined period (for example, about 40 to 50 days in the case of daikon radish). When the root vegetable to be grown is daikon radish etc., by covering the space between the support rail 220 and the nutrient solution tank 210 with a light-shielding curtain etc. to block light, it is possible to suppress the roots from turning green. During growth, except in cases such as when a new seedbed 20 is added, there is no need to move the seedbed 20. During growth in the second unit 200, the seedlings increase in thickness without significantly increasing their root length. Once the roots have reached a sufficient thickness, the operator removes and harvests the crops grown from the seedbed 20. Even if the diameter of the grown roots is larger than the inner diameter of the holes formed in the plate 21, they can be easily removed by separating the first plate 21a and the second plate 21b.

[0029] As described above, in the second unit 200, the process of thickening the roots of a large number of seedlings can be easily carried out from the installation to the harvest of the seedlings. Also, since the nutrient solution tank 210 is in the shape of a half-pipe extending in one direction, a relatively small amount of nutrient solution can be used to grow a large number of seedlings.

[0030] The stopper 25 of the seedbed 20 to which the seedlings are applied is composed of two sponges 26, so the seedlings can be easily passed through the first cut 27a. After the seedlings have passed through the stopper 25, the directions in which the two first cuts 27a extend are different, so it is possible to preferably prevent the seedlings from slipping out. Furthermore, since the second cut 27b is provided, it is possible to suppress the growth of the roots from being hindered by the spread of the second cut 27b. Also, since the two sponges 26 are overlapped with their uneven surfaces facing each other, it is also preferably suppressed that the two sponges constituting the stopper are displaced in the plane direction.

[0031] Regarding the second unit 200 and the seedbed 20, the following changes are also possible. These changes may be made alone or in combination of two or more. · The nutrient solution tank 210 may be divided into a plurality of sections, and nutrient solutions with different nutrient compositions and amounts of nutrients may be arranged for each section. · A circulator may be installed to constantly stir the air in the space between the support rail 220 and the nutrient solution tank 210. By doing so, it is possible to prevent spore colonies of mold from adhering to the surface of the roots during growth. · The stopper of the seedbed may be formed of a material other than sponge (for example, a sheet made of rubber or elastomer). · In the seedbed plate, a lock may be provided to hold the first plate 21a and the second plate 21b in a non-separable state. By doing so, there are advantages such as making it easier to install the seedbed with seedlings on the support rail, and preventing the first plate 21a and the second plate 21b from separating as the roots grow.

[0032] As described above, the hydroponic cultivation device 1 according to the present embodiment enables efficient cultivation and harvesting of a large amount of root vegetables due to various effects exhibited by the first unit 100 and the second unit 200. The hydroponic cultivation device 1 can greatly contribute to the practical implementation of hydroponic cultivation of root vegetables in a profitable manner while it is currently in the process of practical implementation. Since the effects exhibited by the first unit 100 and the effects exhibited by the second unit 200 are not all closely related, a hydroponic cultivation device equipped with only one of the first unit 100 and the second unit 200 can also be expected to sufficiently contribute to the practical implementation of hydroponic cultivation of root vegetables.

[0033] Normally, in the cultivation of root vegetables, the roots are buried in the soil, so it is difficult to monitor the growth status. However, in the cultivation using the hydroponic cultivation device 1, since there is no soil around the growing roots, the growth status can be monitored at any time, and harvesting can be performed at an appropriate timing.

[0034] As another method, as shown in FIG. 8, when a load cell 230 is attached to the lower surface of the seedbed 20 and positioned between the support rails 220, the weight of the crop can be monitored more accurately by subtracting the weight of the seedbed 20 etc. from the output value of the load cell 230. Further, by photographing the roots and leaves of the crop at a predetermined cycle with the camera installed in the second unit 200 and preliminarily obtaining the relationship between the root dimensions calculated based on the image and the weight obtained by the load cell 230, it becomes possible to grasp the growth status of the crop with a certain degree of accuracy using only the obtained images of the roots and leaves. By combining this, the involvement of personnel in crop production using the hydroponic cultivation device 1 can be reduced, and production can be made more efficient.

[0035] The hydroponic cultivation device 1 according to this embodiment has the advantage that it can contribute not only to the efficient production of root vegetables but also to the elucidation of the growth mechanisms of leafy vegetables, root vegetables, and the like. For example, various information that is extremely difficult to obtain in open-field cultivation, such as the relationship between the intensity and wavelength profile of light irradiated on crops and the growth mode (growth amount, growth rate, etc.), the relationship between the components contained in the nutrient solution and the growth mode, and the relationship between temperature, humidity, and the growth mode, can be easily obtained by the hydroponic cultivation device 1. Based on the knowledge obtained from these, it is also expected to optimize various settings in the hydroponic cultivation device, further improve production efficiency, and adjust the shipping timing. This advantage becomes more prominent by providing means for detecting weight such as the load cell described above and means for acquiring images of crops such as cameras. In the studies conducted by the inventors using a load cell and a camera, it has been clarified that the degree of growth of daikon radish is greater in the time zone when light is not irradiated, which is knowledge that has not been known so far. Based on this knowledge, by optimizing the distribution and arrangement of the time zones with and without light irradiation without being restricted by the natural state of approximately 24-hour cycles, it may be possible to increase the production efficiency to a level that is impossible in open-field cultivation.

[0036] Although one embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and it also includes configuration changes, combinations, etc. within the scope not departing from the gist of the present invention.

[0037] For example, in the first unit, if the water surfaces of the plurality of nutrient solution tanks are stepped, it is not necessarily required that the nutrient solution tanks themselves be arranged in a stepped manner. However, arranging the nutrient solution tanks in a stepped manner results in the bottom surfaces of the nutrient solution tanks also being arranged in a stepped manner, which can reduce the amount of nutrient solution used for the entire unit and also reduce the amount of interference between the roots and the nutrient solution tanks when moving the seedbed to the next unit. Therefore, it is preferable to make the water surface of the nutrient solution stepped by arranging the nutrient solution tanks in a stepped manner. In the first unit, the distance between the seedbed and the nutrient solution water surface is the shortest in the section where the seedbed 10 is first installed, and the above-described effect can be achieved if the distance gradually increases as it moves to the adjacent section. Therefore, in addition to the embodiment shown, the following configurations may also be used. · The height of the nutrient solution water surface is the same in all the nutrient solution tanks, but the upper surface of the frame 110 that supports the seedbed gradually increases stepwise. · The upper surface of the frame 110 gradually increases stepwise, and the height of the nutrient solution water surface gradually decreases stepwise. · Both the height of the nutrient solution water surface and the upper surface of the frame 110 gradually increase, but the increase amount of the height of the upper surface of the frame 110 exceeds the increase amount of the height of the nutrient solution water surface. · Both the height of the nutrient solution water surface and the upper surface of the frame 110 gradually decrease, but the decrease amount of the height of the nutrient solution water surface exceeds the decrease amount of the height of the upper surface of the frame 110.

[0038] In the hydroponic cultivation apparatus according to the present invention, as shown in FIG. 9, a plurality of second units 200 may be vertically stacked. Thereby, the yield of crops per unit floor area can be increased, and it is also possible to improve to a level that is impossible in open field cultivation. Of course, it is also possible to stack a plurality of first units 100 in the vertical direction, whereby the seedlings supplied to the second unit 200 can be produced more efficiently.

[0039] The application of the hydroponic cultivation apparatus 1 is not limited to the above-described daikon radish, and is also applicable to other root vegetables such as turnips, burdocks, carrots, and ginseng.

Explanation of Reference Numerals

[0040] 1 Hydroponic cultivation apparatus 10 Seedbed 20 Seedbed 100 First unit (root elongation part) 110 Frame (support part) 111, 112, 113, 114, 115 Nutrient solution tank 200 Second unit 210 Nutrient solution tank 220 support rail

Claims

1. A hydroponic cultivation device comprising a root elongation part for growing the roots of seedlings, wherein the root elongation part includes a plurality of nutrient solution tanks arranged in one direction with nutrient solution disposed therein and arranged side by side, and a support part for supporting a seedling bed disposed above the nutrient solution tanks, and the distance between the water surface of the nutrient solution disposed in each of the nutrient solution tanks and the support part gradually increases from one side to the other side in the one direction. Hydroponic cultivation device.

2. The water surface of the nutrient solution disposed in each of the nutrient solution tanks is in a stepped shape that gradually becomes lower from one side to the other side in the one direction. The hydroponic cultivation device according to Claim 1.

3. The plurality of nutrient solution tanks are arranged at the highest position on one side in the one direction and are arranged to gradually become lower toward the other side. The hydroponic cultivation device according to Claim 2.

4. The hydroponic cultivation device further comprises a second unit where the seedlings grown in the root elongation part are installed, and the second unit includes a nutrient solution tank extending in one direction and a support rail for supporting a seedling bed disposed above the nutrient solution tank, and is configured such that only the tip of the root of the seedling installed on the seedling bed is located in the nutrient solution tank. The hydroponic cultivation device according to Claim 1.

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