Plant cultivation equipment

Abstract

To provide a culture apparatus capable of remarkably improving utilization efficiency of a nutrient solution containing a fertilizer and water by carrying out speed control by non-circulation in which the nutrient solution is adjusted to the fertilizer having a proper concentration without being circulated and applied.SOLUTION: A plant cultivation apparatus of the present invention is a plant cultivation apparatus in a closed plant factory for cultivating a plant indoors where sunlight is blocked, the plant cultivation apparatus including a cultivation tray configured to hold a nutrient solution containing water and a fertilizer and to hold a plant whose roots are soaked in the nutrient solution, and a nutrient solution tank configured to supply an additional nutrient solution to the cultivation tray, wherein the nutrient solution in the cultivation tray is held in the cultivation tray without being circulated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a plant cultivation device used for performing hydroponics without using soil in a plant factory or the like. [Background technology]

[0002] In closed plant factories and other facilities where sunlight is blocked and artificial light such as LED light sources is used to grow plants, hydroponics, which uses a nutrient solution instead of soil, has become the norm. Hydroponics include a spray method in which the nutrient solution is directly sprayed onto the roots of plants in a mist using a spray nozzle, but the mainstream method is a circulation method in which the nutrient solution is circulated by running it through pool-like channels called cultivation beds (or cultivation trays) that are several to 20 meters long. For example, Patent Document 1 discloses a nutrient solution supplying device for a conventional plant cultivation facility.

[0003] This recirculating hydroponic system uses a pump to supply fertilizer dissolved in water to the plant roots through a supply nozzle on the surface of the cultivation bed, circulating the solution throughout the cultivation bed. This facilitates direct fertilizer absorption by the roots and also provides dissolved oxygen, promoting plant growth. However, because the roots are constantly moving due to the flow of the nutrient solution, plant waste and allelopathic substances leach from the roots into the cultivation bed. If these substances accumulate, they can inhibit plant growth and lead to contamination of the cultivation bed. For this reason, the nutrient solution in the cultivation beds must be periodically renewed (replaced). A recirculating nutrient solution tank is installed to hold a volume of renewal nutrient solution equivalent to the volume of the cultivation bed. In large-scale facilities, tens of tons of nutrient solution must be discharged at a time for renewal, resulting in a waste of water resources and significant environmental risks, such as the nitrogen and phosphate fertilizers contained in the nutrient solution contributing to eutrophication.

[0004] Furthermore, automation has recently been implemented in large-scale plant factories to compensate for labor shortages. One method of automation is to use cultivation trays with short cultivation bed lengths of approximately 1.5 m, which are easily transportable, and to transport these cultivation trays while circulating nutrient solution in the same manner as described above. This method aims to improve work efficiency by transporting the cultivation trays according to the growth of the plants. However, automation presents challenges, such as spurting nutrient solution from the supply port of the cultivation tray or spilling the nutrient solution from the cultivation tray during transport because the trays are still in nutrient solution, which can cause breakdowns in the automated machinery.

[0005] Furthermore, spillage of the nutrient solution can lead to contamination of the plants being cultivated, and problems arise in terms of hygiene management, such as an increase in the number of live bacteria, which means that the space where the cultivation trays are placed needs to be cleaned frequently, resulting in other issues such as an increased workload. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-021065 Summary of the Invention [Problem to be solved by the invention]

[0007] In order to solve the above problems, the present invention provides a new hydroponic cultivation method that does not circulate nutrient solution and a cultivation device used for the method, which dramatically improves the efficiency of fertilizer and water use in a closed plant factory where plants are cultivated using artificial light such as an LED light source in a room that is shielded from sunlight.

[0008] In contrast to the conventional circulation-type concentration control in plant cultivation in plant factories, in which the nutrient solution is circulated and the concentration is controlled based on EC (electrical conductivity), the present invention aims to dramatically improve the utilization efficiency of the nutrient solution containing fertilizer and water and to make it easier to transport cultivation trays during automation by using a non-circulation-type speed control in which the nutrient solution is not circulated but is adjusted to an appropriate concentration and applied. [Means for solving the problem]

[0009] A plant cultivation device according to one embodiment of the present invention includes: A plant cultivation device in a closed plant factory that cultivates plants indoors while shielding from sunlight, A cultivation tray that holds a nutrient solution containing water and fertilizer and holds plants with their roots immersed in the nutrient solution; a nutrient solution tank for supplying additional nutrient solution to the cultivation tray; The nutrient solution in the cultivation tray is retained in the cultivation tray without being circulated. It is a plant cultivation device.

[0010] This type of cultivation device and cultivation method using the same device eliminates the need to prepare circulating nutrient solution, which reduces the amount of nutrient solution used by about half compared to conventional circulation-type cultivation devices and methods. In addition, the amount of waste solution discharged can be reduced or eliminated, providing an environmentally friendly cultivation device and method.

[0011] In the above-mentioned cultivation device, preferably, Further, a control unit is provided to control the supply of additional nutrient solution from the nutrient solution tank to the cultivation tray. The control unit supplies the additional nutrient solution from the nutrient solution tank to the cultivation tray at a predetermined timing.

[0012] According to such a cultivation device and a cultivation method using the same device, it is possible to provide a plant cultivation device and method that can manage the nutrient solution relatively easily compared to conventional methods.

[0013] In the above cultivation device, preferably, the electrical conductivity of the nutrient solution and the additional nutrient solution is approximately twice that of the nutrient solution in a conventional circulation-type cultivation device that circulates water in the cultivation tray.

[0014] In the above cultivation device, preferably, the electrical conductivity of the nutrient solution and the additional nutrient solution is 2.0 m S / cm or more and 2.4 m S / cm or less.

[0015] According to such a cultivation device and a cultivation method using the same device, in the cultivation device of the present invention different from the conventional circulation-type cultivation device, it is possible to appropriately manage the ratio of fertilizers and the like contained in the nutrient solution.

[0016] In the above cultivation device, preferably, the nutrient solution tank can supply two or more of the additional nutrient solutions having different fertilizer concentrations and / or compositions to the cultivation tray, and the control unit supplies any one of the two or more additional nutrient solutions to the cultivation tray at a predetermined timing according to the growth of the plants held in the cultivation tray.

[0017] According to such a cultivation device and a cultivation method using the same device, it is possible to appropriately manage the ratio of fertilizers and the like contained in the nutrient solution.

Advantages of the Invention

[0018] According to the plant cultivation device of one embodiment of the present invention, compared with the conventional circulation-type cultivation device and method, since there is no need to prepare a nutrient solution for circulation, the amount of nutrient solution used can be reduced to about half. In addition, it is possible to reduce or eliminate the amount of waste liquid discharged. [[ID=3**]]

Brief Description of the Drawings

[0019] [Figure 1] It is a conceptual diagram of a plant cultivation device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that the embodiment described below is merely a specific example for carrying out the present invention, and is not to be construed as limiting the present invention.

[0021] As described above, the plant cultivation device of this embodiment is a new hydroponic cultivation method that does not circulate nutrient solution and dramatically improves the efficiency of fertilizer and water use in a closed plant factory where plants are cultivated using artificial light such as an LED light source in a room that is shielded from sunlight, and is also a cultivation device used for this method.

[0022] As shown in FIG. 1 , a plant cultivation device 1 in this embodiment includes a cultivation tray 2, a nutrient solution tank 3, and a control unit 4. In a plant factory, a large number of cultivation trays 2 are arranged in a cultivation area of ​​a cultivation shelf, and each of these cultivation trays 2 is movable using an arm or the like. When supplying nutrient solution (additional nutrient solution, described below) to the cultivation tray 2, the cultivation tray 2 is moved to a nutrient solution supply area where the nutrient solution tank 3 and the control unit 4 are arranged. In the nutrient solution supply area, nutrient solution is supplied from the nutrient solution tank 3 under the control of the control unit 4, and then the cultivation tray 2 is returned to the cultivation area where it was originally placed. This configuration eliminates the need to provide a nutrient solution tank 3 or the like for each cultivation tray 2, enabling space-saving and efficient arrangement and providing various advantages, such as easier management of the nutrient solution.

[0023] The cultivation tray 2 used for cultivation is, for example, approximately 70 cm wide, 130 cm long, and 5 cm deep. Nutrient solution 21 is poured into the cultivation tray 2, and the nutrient solution 21 is retained for the cultivation of the target plants 23. A cultivation panel 22 formed with an array of multiple holes, each approximately 2.5 cm in diameter, for planting the plants 23 is provided on top of the cultivation tray 2. In one example of a plant factory, many of these cultivation devices 1 are arranged vertically and horizontally on cultivation shelves, and artificial light sources such as LEDs are irradiated from above the plants 23, and cultivation is carried out indoors with constant controlled temperature, humidity, and carbon dioxide concentration.

[0024] In the nutrient solution supply area, nutrient solution is supplied to the cultivation tray 2 through a nozzle from a nutrient solution tank 3 containing nutrient solution prepared to an appropriate fertilizer concentration under the control of a control unit 4, which functions as an automatic nutrient solution supply device. The control unit 4 is, for example, a semiconductor device such as a microcomputer or a computer such as a PC running predetermined software. For convenience, the nutrient solution held and supplied by the nutrient solution tank 3 is sometimes referred to as "additional nutrient solution" to distinguish it from the nutrient solution 21 held in the cultivation tray 2 at the beginning of cultivation. The cultivation tray 2 holds the nutrient solution 21 to be supplied to plants 23, just like a conventional cultivation bed. However, because it is smaller in size than a conventional cultivation bed, it is referred to as a "cultivation tray," and there is no significant difference between the two. Because of its relatively small size, the cultivation tray 2 can be transported relatively easily between the cultivation area and the nutrient solution supply area.

[0025] The nozzle of the nutrient solution tank 3 is equipped with a water level sensor, which allows additional nutrient solution to be supplied to the cultivation tray 2 so as to maintain the desired water level. However, the nutrient solution tank 3 does not supply additional nutrient solution to the cultivation tray 2 as needed to maintain the water level, but rather supplies a predetermined amount of additional nutrient solution to the cultivation tray 2 at a predetermined timing, as described below.

[0026] A plurality of nutrient solution tanks 3 are provided to change the concentration and / or composition of the fertilizer contained in the supplemental nutrient solution to be supplied according to the growth stage of the plant 23. Specifically, as shown in this embodiment, two nutrient solution tanks 31 and 32 are provided. For appropriate management of the plant 23, for example, it is preferable to divide the concentration and / or composition of the fertilizer contained in the nutrient solution 21 into three or more stages, as described below. That is, it is preferable that the cultivation device 1 is configured to include two or more nutrient solution tanks 3 so that the nutrient solution 21 is first supplied to the cultivation tray 2 and then two types of supplemental nutrient solution can be automatically supplied to the cultivation tray 2 at predetermined times. Note that the configuration and method are not limited to these, and the configuration and method may be changed depending on the plant 23 to be cultivated. The concentration and / or composition of the fertilizer in the nutrient solution 21 or the supplemental nutrient solution is sometimes referred to as the "fertilizer concentration."

[0027] The control unit 4 controls the supply of additional nutrient solution from the nutrient solution tank 3 to the cultivation tray 2 at a predetermined timing, for example. More specifically, for example, the control unit 4 measures the number of days since the start of cultivation using an internal timer or an external timer, and supplies a predetermined amount of additional nutrient solution from the nutrient solution tank 31 to the cultivation tray 2 10 days after the start of cultivation, and then supplies a predetermined amount of additional nutrient solution from the nutrient solution tank 32 to the cultivation tray 2 7 days later. As described above, when additional nutrient solution is supplied from the nutrient solution tank 31 or 32 to the cultivation tray 2, the cultivation tray 2 is moved from the cultivation area to the nutrient solution supply area. That is, the cultivation tray 2 is moved to the nutrient solution supply area at a first timing and supplied with additional nutrient solution (first additional nutrient solution) from the nutrient solution tank 31, and at a second timing and supplied with additional nutrient solution (second additional nutrient solution) from the nutrient solution tank 32. At the start of cultivation, the cultivation tray 2 is manually supplied with nutrient solution 21 suitable for the initial stage of cultivation. The supply (replenishment) of the nutrient solution 21 to the cultivation tray 2 is not carried out at any other times than the above.

[0028] In conventional circulating hydroponic systems, the nutrient solution is circulated, causing a flow of the nutrient solution within the nutrient solution, and plants absorb the necessary fertilizer components from this flowing nutrient solution through their roots. On the other hand, in the cultivation device 1 of this embodiment, which employs a non-circulating cultivation method in which the nutrient solution 21 is not circulated, the nutrient solution does not circulate or flow, resulting in a decrease in the amount of nutrient solution absorbed by the roots. To compensate for this behavior, in the cultivation device 1 of this embodiment, the fertilizer concentration of the nutrient solution 21 and the additional nutrient solution supplied from the nutrient solution tank 3 is increased to about twice that of the conventional circulating system.

[0029] Specifically, in a conventional circulation system, the fertilizer concentration of the nutrient solution 21 is adjusted by measuring the electrical conductivity (EC) of the nutrient solution 21 with a sensor, and when the electrical conductivity (EC) is 1 m The control unit controlled the pressure to about S / cm.

[0030] On the other hand, in the cultivation device 1 of this embodiment, the electrical conductivity (EC) of the nutrient solution 21 and the additional nutrient solution in the nutrient solution tank 3 is set to 2.2 m ±0.2 centered on S / cm m S / cm, 2.0 m S / cm or more 2.4 m The fertilizer concentration of the additional nutrient solution supplied from the nutrient solution tank 3 and the fertilizer concentration of the nutrient solution 21 are controlled by the control unit 4 to be about twice that of the conventional circulation system. The fertilizer concentration of the additional nutrient solution in the nutrient solution tank 3 is prepared to be appropriate for each growth stage of the plant 23, so that additional nutrient solution can be supplied in accordance with the growth of the plant 23.

[0031] As a result, in the cultivation device 1 of this embodiment, the plant 23 can absorb an appropriate amount of fertilizer components through its roots, and the plant 23 can grow at the same rate as in the conventional case.

[0032] [An example of a method for cultivating leaf lettuce using the cultivation device 1] In the non-circulating cultivation method of the cultivation apparatus 1 of this embodiment, the amount of nutrient solution 21 in the cultivation tray 2 is not kept constant, and therefore, the amount of nutrient solution 21 decreases as the plants 23 grow. In the early stages of cultivation after planting the plants 23, the decrease in the amount of nutrient solution 21 is gradual because the plants 23 are still small. For example, when leaf lettuce is cultivated using this method, it is not necessary to add nutrient solution 21 until around the 10th day. After about the 7th to 10th day, nutrient solution (additional nutrient solution) prepared to a concentration and composition suitable for the middle stage of cultivation is supplied to the cultivation tray 2 from the nutrient solution tank 3, and cultivation is continued. In the middle stage of cultivation, the amount of nutrient solution 21 decreases within about 5 to 7 days, and at this timing, nutrient solution (additional nutrient solution) prepared to a concentration and composition suitable for the later stage of cultivation is supplied from the nutrient solution tank 3 to the cultivation tray. In the later stage of cultivation, leaf lettuce grows exponentially, and reaches a harvest size exceeding 100 g fresh weight in about 3 to 5 days. At this time, only a small amount of the nutrient solution 21 remains in the cultivation tray 2.

[0033] In the example of leaf lettuce grown using the non-recycle method of this embodiment, the stems above ground tend to be thicker and the overall shape is sturdy, whereas in the case of the conventional recycle method, the stems tend to be leggy, resulting in different plant shapes.

[0034] Furthermore, with this non-circulating system, the nutrient solution 21 is always stationary and the water level of the nutrient solution 21 drops (changes) as the plant grows, resulting in the development of many root hairs. Furthermore, as the roots do not move, there is less stress, making it difficult for waste products to elute from the roots, and the roots remain white; therefore, the phenomenon of roots turning brown and waste products eluting into the nutrient solution 21, which is seen with the circulating system, are not observed.

[0035] Thus, the cultivation device 1 according to one embodiment of the present invention is a cultivation device for plants in a closed plant factory where plants are cultivated indoors shielded from sunlight, and includes a cultivation tray 2 and a nutrient solution tank 3. The cultivation tray 2 holds a nutrient solution 21 containing water and fertilizer, and holds plants 23 with their roots immersed in the nutrient solution 21. The nutrient solution tank 3 supplies additional nutrient solution to the cultivation tray 2. The nutrient solution 21 in the cultivation tray 2 is held in the cultivation tray 2 without being circulated.

[0036] The cultivation device 1 further includes a control unit 4 that controls the supply of additional nutrient solution from the nutrient solution tank 3 to the cultivation tray 2. The control unit 4 supplies the additional nutrient solution from the nutrient solution tank 3 to the cultivation tray 2 at a predetermined timing that has been set in advance.

[0037] In addition, in the above-mentioned cultivation device 1, the electrical conductivity of the nutrient solution 21 and the additional nutrient solution is set to be approximately twice the electrical conductivity of the nutrient solution in a conventional circulation-type cultivation device that circulates water in the cultivation tray. m S / cm or more 2.4 m It is preferable to set it to S / cm or less.

[0038] In the above-described cultivation device 1, the nutrient solution tank 3 includes a first nutrient solution tank 31 that holds a first additional nutrient solution, and a second nutrient solution tank 32 that holds a second additional nutrient solution that has a different fertilizer concentration and / or composition from the first additional nutrient solution. The control unit 4 supplies the first additional nutrient solution from the first nutrient solution tank 31 to the cultivation tray 2 at a first timing in accordance with the growth of the plants 23 held in the cultivation tray 2, and supplies the second additional nutrient solution from the second nutrient solution tank 32 to the cultivation tray 2 at a second timing.

[0039] According to the cultivation apparatus 1 of the present invention and the cultivation method using the same apparatus, the cultivation trays 2 are independent of each other, and a non-circulating system is used in which the nutrient solution 21 is not circulated, and the rate at which the nutrient solution 21 is appropriately replenished according to the growth of the plants 23 is managed, so that the remaining amount of nutrient solution 21 can be reduced to almost zero at the time of harvest, and the nutrient solution 21 can be used without waste. Therefore, the amount of nutrient solution 21 used is less than half that of conventional circulating cultivation systems, and furthermore, no wastewater is produced, making this an environmentally friendly cultivation system. [Explanation of symbols]

[0040] 1...Cultivation equipment 2. Cultivation tray 21...Nutrient solution 22...Cultivation panel 23...plant 3, 31, 32, nutrient solution tank 4...Control device

Claims

1. A plant cultivation device in a closed plant factory that cultivates plants indoors while shielding from sunlight, A cultivation tray that holds a nutrient solution containing water and fertilizer and holds plants with their roots immersed in the nutrient solution; a nutrient solution tank for supplying additional nutrient solution to the cultivation tray; The nutrient solution in the cultivation tray is kept stationary in the cultivation tray without being circulated, Further, a control unit is provided to control the supply of additional nutrient solution from the nutrient solution tank to the cultivation tray. the control unit supplies the additional nutrient solution from the nutrient solution tank to the cultivation tray at a predetermined timing, The nutrient solution tank includes a first nutrient solution tank that holds a first additional nutrient solution, and a second nutrient solution tank that holds a second additional nutrient solution that has a fertilizer concentration and / or composition different from that of the first additional nutrient solution, the control unit supplies the first additional nutrient solution from the first nutrient solution tank to the cultivation tray at a first timing in accordance with the growth of the plant held in the cultivation tray, and supplies the second additional nutrient solution from the second nutrient solution tank to the cultivation tray at a second timing; The first additional nutrient solution and the second additional nutrient solution are nutrient solutions each prepared to an appropriate fertilizer concentration. Plant cultivation equipment.

2. The electrical conductivity of the nutrient solution and the additional nutrient solution is approximately twice the electrical conductivity of the nutrient solution in a conventional circulation-type cultivation device that circulates water in the cultivation tray. The plant cultivation device according to claim 1.

3. The electrical conductivity of the nutrient solution and the additional nutrient solution is 2.0 mS / cm or more and 2.4 mS / cm or less; The plant cultivation device according to claim 1.

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