Hydroponic cultivation system and hydroponic cultivation method

Abstract

The present invention provides a hydroponic cultivation system and method that enable the harvesting of fruits at a higher yield than conventional methods. [Solution] A nutrient solution tank, a cultivation tank for growing plants, a liquid delivery mechanism for sending nutrient solution from the nutrient solution tank to the cultivation tank, piping connecting the nutrient solution tank, the cultivation tank, and the liquid delivery mechanism, and means for monitoring the state of the nutrient solution flowing through the piping and at least one of the inner walls of the piping. A hydroponic cultivation system for growing fruits and vegetables, comprising: a piping system having straight sections and curved sections, at least a portion of the curved sections of the piping being made of a flexible, soft material, and the curved sections of the piping being detachably connected to the straight sections of the piping.

Description

[Technical Field]

[0001] This disclosure relates to a hydroponic cultivation apparatus and a hydroponic cultivation method. [Background technology]

[0002] In recent years, there has been a growing demand for vegetable production in plant factories using artificial light. While production techniques for some leafy vegetables, such as lettuce, have advanced, there is a need to explore cultivation methods for fruiting vegetables like tomatoes.

[0003] For example, Patent Document 1 describes a plant cultivation device comprising a cultivation container arranged in any manner in a room or the like, a drainage and water supply pipe arranged in an appropriate manner in a greenhouse or the like, and a connecting tube that connects the drainage and water supply pipe to the inside of the cultivation container, wherein the connecting tube is made of a flexible tube body and is formed to be detachably connected to a connecting pipe fixed to the drain hole of the cultivation container, and the drainage and water supply pipe is formed to be supplied with plant cultivation liquid pressurized by an appropriate pressure device, and the plant cultivation liquid is supplied to the cultivation container via the connecting tube. Patent Document 2 describes a hydroponic water tank for hydroponics in which a plurality of openings for observation or work are formed in the side wall of the light-shielding water tank for hydroponics, a light-shielding lid is fitted liquid-tightly to these openings, and a light source for illuminating the plants being cultivated is provided inside the water tank. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-38642 [Patent Document 2] Japanese Utility Model Publication No. 7-28340 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the cultivation of fruit vegetables, the growing period is generally longer than that of leafy vegetables, and the accumulation of dirt during cultivation can sometimes lead to a decrease in the yield of harvested fruit.

[0006] One embodiment of this disclosure aims to solve the problem of providing a hydroponic cultivation apparatus and method that can harvest fruit at a higher yield than conventional methods. [Means for solving the problem]

[0007] This disclosure includes the following aspects: <1> Nutrient solution tank and A cultivation tank for growing plants, A nutrient solution transfer mechanism that sends nutrient solution from the nutrient solution tank to the cultivation tank, Piping that connects the nutrient solution tank, the cultivation tank, and the liquid delivery mechanism, Means for understanding the state of the nutrient solution flowing through the pipe and the state of at least one of the inner walls of the pipe, Equipped with, The piping has straight sections and curved sections. At least a portion of the curved section of the piping is formed from a flexible, soft material. The curved section of the piping and the straight section of the piping are connected in a separable manner. A hydroponic system used for cultivating fruits and vegetables. <2> As a means of understanding the condition, the piping is equipped with a viewing window. A removable light-blocking member is provided on the outside of the viewing window. <1> The hydroponic cultivation system described above. <3> Fruit vegetables are plants of the Solanaceae family or the Cucurbitaceae family. <1> or <2> The hydroponic cultivation system described above. <4> The system further includes a light source that irradiates the plant body with artificial light from at least one of its side and top surfaces. <1> ~ <3> A hydroponic cultivation device as described in any one of the following. <5> <1> ~ <4> A hydroponic cultivation method for growing fruit vegetables using a hydroponic cultivation apparatus described in any one of the following, During or after the cultivation period of fruit vegetables, a step of removing the curved portion of the pipe, cleaning the straight portion of the pipe, and cleaning the curved portion of the pipe or replacing the curved portion of the pipe with a new one, a hydroponic cultivation method including these steps. <6> A hydroponic cultivation method for cultivating fruit vegetables using the hydroponic cultivation device according to any one of <1> to <4>, a step of determining the timing of cleaning the pipe based on information obtained using means for grasping the state, a step of removing the curved portion of the pipe during or after the cultivation period of fruit vegetables based on the determination result, cleaning the straight portion of the pipe, and cleaning the curved portion of the pipe or replacing the curved portion of the pipe with a new one, a hydroponic cultivation method including these steps.

Effect of the Invention

[0008] According to one embodiment of the present disclosure, a hydroponic cultivation device and a hydroponic cultivation method capable of harvesting fruits with a higher yield than conventional ones are provided.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing one embodiment of a hydroponic cultivation device according to the present disclosure.

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless specifically stated. The same applies to numerical values and their ranges, which do not limit the present disclosure. In the present disclosure, in the numerical range indicated by using "~", the numerical values described before and after "~" are included as the minimum value and the maximum value, respectively. In the numerical ranges described step by step in this disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. Also, in the numerical ranges described in this disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. In this disclosure, the term "step" includes not only an independent step but also a step whose intended purpose is achieved even if it cannot be clearly distinguished from other steps. In this disclosure, "fruiting vegetables" means plants whose fruits are the harvest.

[0011] [Hydroponic cultivation device] The hydroponic cultivation device according to this disclosure includes a nutrient solution tank, a cultivation tank for cultivating plants, a liquid feeding mechanism for sending the nutrient solution from the nutrient solution tank to the cultivation tank, pipes for connecting the nutrient solution tank, the cultivation tank, and the liquid feeding mechanism to each other, means for grasping at least one of the state of the nutrient solution passing through the pipes and the inner wall of the pipes, the pipes have straight portions and curved portions, at least a part of the curved portion of the pipes is formed of a flexible soft member, the curved portion of the pipes and the straight portion of the pipes are separably connected, and it is used for cultivating fruiting vegetables.

[0012] According to the hydroponic cultivation device according to this disclosure, fruits can be harvested in a higher yield than before.

[0013] In the cultivation of fruit and vegetable crops, the cultivation period is generally longer than that of leafy vegetables, and dirt accumulates during cultivation. Since the nutrient solution contains components necessary for the growth of fruit and vegetable crops, the inside of the pipes is a breeding ground for algae, fungi, etc., and easily accumulates as dirt. The hydroponic cultivation system according to this disclosure is equipped with means for monitoring the condition of the nutrient solution flowing through the pipes and at least one of the inner walls of the pipes, so that dirt inside the pipes that occurs during the cultivation of fruit and vegetable crops can be monitored. Furthermore, since at least a portion of the curved section of the pipes is formed of a flexible soft material, and the curved section and the straight section of the pipes are detachably connected, it is possible to clean or replace the pipes even in the middle of the cultivation period. During the long cultivation period, the inhibition of fruit and vegetable crop growth by dirt inside the pipes is suppressed, and fruit can be harvested at a higher yield than before. In particular, since the cultivation period for fruit and vegetable crops is long, the ability to clean or replace the pipes in the middle of the cultivation period is a major advantage.

[0014] In contrast, Patent Documents 1 and 2 do not contain any technical concept of providing a means for understanding the state of at least one of the nutrient solution flowing through the pipe and the inner wall of the pipe.

[0015] <Fruit vegetables> Fruiting vegetables are not particularly limited and include plants of the Solanaceae family such as tomatoes, eggplants, and bell peppers; plants of the Cucurbitaceae family such as melons, cucumbers, pumpkins, and zucchini; plants of the Fabaceae family such as green beans, peas, and broad beans; plants of the Rosaceae family such as strawberries; plants of the Malvaceae family such as okra; and grasses such as corn.

[0016] In particular, the hydroponic cultivation apparatus according to this disclosure is suitable for cultivating plants of the Solanaceae family or Cucurbitaceae family. The fruit vegetables cultivated in the hydroponic cultivation apparatus according to this disclosure are preferably plants of the Solanaceae family or Cucurbitaceae family, more preferably tomatoes or melons, and even more preferably tomatoes.

[0017] Tomatoes include varieties such as midi tomatoes, cherry tomatoes, and fruit tomatoes. Melons, on the other hand, include varieties such as green-fleshed and red-fleshed netted melons and non-netted melons.

[0018] The following describes the various components of the hydroponic cultivation system related to this disclosure, with reference to Figure 1.

[0019] Figure 1 is a schematic cross-sectional view showing one embodiment of the hydroponic cultivation apparatus according to this disclosure.

[0020] As shown in Figure 1, the hydroponic cultivation apparatus 100 comprises a nutrient solution tank 10, a cultivation tank 21 for cultivating plant bodies 80, a liquid supply mechanism 30 for sending nutrient solution from the nutrient solution tank 10 to the cultivation tank 21, piping (straight pipe 41, curved pipe 42, discharge pipe 43) connecting the nutrient solution tank 10, the cultivation tank 21, and the liquid supply mechanism 30 to each other, a viewing window 50, and a light source 60.

[0021] <Nutrient solution tank> The nutrient solution tank 10 stores nutrient solution for supply to the cultivation tank 21.

[0022] The components contained in the nutrient solution are not particularly limited, but from the viewpoint of promoting plant growth, it is preferable to include at least one selected from the group consisting of nitrogen, phosphorus, potassium, magnesium, calcium, and sulfur. The nutrient solution can be a commercially available liquid fertilizer that has been diluted to the appropriate level.

[0023] <Cultivation tank> The cultivation tank 21 contains a nutrient solution for immersing the roots of the plant body 80. The contained nutrient solution is absorbed from the roots into the plant body. In the hydroponic cultivation system 100 shown in Figure 1, there is only one cultivation tank, but there may be two or more cultivation tanks. For example, multiple cultivation shelves may be provided in the vertical direction, and a cultivation tank may be placed on each cultivation shelf. If there are two or more cultivation tanks, there may be only one nutrient solution tank. The one nutrient solution tank and each cultivation tank may be connected by piping as described later.

[0024] A lid 22 is provided on top of the cultivation tank 21 to cover it. The lid 22 has holes large enough for the stems of the plant bodies 80 to pass through. The number of holes should be determined according to the number of plants to be cultivated in the cultivation tank 21.

[0025] The presence of the lid 22 suppresses light irradiation to the nutrient solution, thereby suppressing the growth of algae, fungi, and other organisms in the cultivation tank 21.

[0026] Furthermore, it is preferable that the surface of the lid 22 opposite to the side facing the cultivation tank 21 has a light-reflecting function. The lid 22 itself may be formed of a light-reflecting material. Alternatively, a light-reflecting material such as a light-reflecting plate or light-reflecting sheet may be attached to the surface of the lid 22.

[0027] Examples of light reflectors include metal plates (such as aluminum plates) and resin plates (white resin plates). Examples of light-reflective sheets include sheets having a metal vapor-deposited film formed by vapor-depositing a metal (such as aluminum) as a light-reflective layer onto a resin sheet (such as polypropylene, polyethylene, or polyethylene terephthalate), sheets having a metal foil (such as aluminum foil) laminated onto the resin sheet as a light-reflective layer, and sheets having a coating film formed by applying a light-reflective paint to the resin sheet as a light-reflective layer.

[0028] The surface of the lid 22 has a light-reflecting function, which allows light shining on the plant body 80 to be reflected back to parts of the plant body 80 other than the roots (i.e., stem, leaves, flowers, fruits, etc.). This can further improve the fruit yield.

[0029] <Liquid delivery mechanism> The liquid delivery mechanism 30 is, for example, a liquid delivery pump, which has the function of delivering nutrient solution from the nutrient solution tank 10 to the cultivation tank 21. In addition, by delivering nutrient solution from the cultivation tank 21 to the nutrient solution tank 10, the nutrient solution can be circulated.

[0030] <Piping> The piping connects the nutrient solution tank 10, the cultivation tank 21, and the liquid delivery mechanism 30 to each other. Combine the straight pipe 41 and the curved pipe 42. As shown in Figure 1, it is preferable that a discharge pipe 43 be placed in the section that supplies nutrient solution to the cultivation tank 21. The arrangement of the straight pipes 41 and curved pipes 42 is not particularly limited, but it is preferable to arrange the straight pipes 41 in the sections where nutrient solution is discharged from the cultivation tank 21, where nutrient solution is supplied to the nutrient solution tank 10, and where nutrient solution is discharged from the nutrient solution tank 10. The curved pipe 42 is preferably positioned between the two straight pipes 41.

[0031] The straight pipe 41 is formed of, for example, a rigid material. Examples of materials for the straight pipe 41 include resins such as polyvinyl chloride and polyolefin resin; and metals such as stainless steel (SUS) and aluminum. When using resin, it is preferable to impart light-shielding properties with pigments, additives, etc. Furthermore, the material of the straight pipe 41 may be only one type, or a combination of multiple types may be used.

[0032] At least a portion of the curved pipe 42 is formed from a flexible, soft material. Examples of materials for the curved piping 42 include resins such as natural rubber, synthetic rubber, and silicone rubber; and metals such as stainless steel (SUS) and aluminum. When using resin, it is preferable to impart light-shielding properties with pigments, additives, etc. The curved piping may also contain reinforcing materials such as fibers or metal, to the extent that it does not impair flexibility. When using metal, it is preferable that it be in the form of a so-called flexible metal hose.

[0033] The straight pipe 41 and the curved pipe 43 are connected in a separable manner. Therefore, it is easy to clean or replace the pipes. In particular, the hydroponic cultivation system described herein is used for cultivating fruit vegetables, and since the cultivation period is longer compared to leafy vegetables, the ease with which the piping can be cleaned or replaced has a significant impact on improving fruit yield.

[0034] <Peephole> As shown in Figure 1, the straight pipe 41 is equipped with a viewing window 50 as a means (hereinafter also referred to as "gathering means") for monitoring the state of the nutrient solution passing through the pipe and the state of at least one of the inner walls of the pipe. The viewing window 50 may be provided in only some of the multiple straight pipes 41, or it may be provided in all of them. Furthermore, the viewing window 50 may be provided in the curved pipe 43, but from the viewpoint of ease of installation, it is preferable that it be provided in the straight pipe 41. The viewing window 50 is not particularly limited as long as it is in a form that allows observation of the state of the nutrient solution passing through the pipe and at least one of the inner walls of the pipe, and is formed of a transparent material that is visible from the outside.

[0035] The presence of the viewing window 50 allows for the assessment of, for example, the clarity of the nutrient solution flowing through the pipe and the presence or absence of foreign matter mixed in the nutrient solution. Furthermore, the presence of the viewing window 50 allows for the assessment of, for example, the presence or absence of foreign matter (e.g., algae) adhering to the inner wall of the pipe and the degree of foreign matter adhering to it.

[0036] This makes it possible to appropriately set the timing for cleaning or replacing the piping. This allows us to minimize the number of cleaning or replacement cycles, thereby reducing damage to plants associated with cleaning or replacing the piping.

[0037] A removable light-shielding member (not shown) is provided on the outside of the viewing window 50. The presence of a light-shielding component suppresses the intrusion of light into the pipe through the viewing window 50, thereby suppressing the growth of algae, bacteria, and other microorganisms inside the pipe. The material of the light-shielding member is not particularly limited and includes, for example, cloth, plastic sheets, and rubber sheets. The light-shielding member may contain additives such as pigments to enhance its light-shielding properties. The material of the light-shielding member may be only one type, or a combination of multiple types.

[0038] <Light source> In the hydroponic cultivation apparatus 100 shown in Figure 1, the light source 60 is located on the side of the plant. Specifically, multiple light sources 60 are arranged at equal intervals along the side of the plant body, parallel to the direction of gravity. By irradiating the plant with artificial light from the side, the size of the plant (especially its height) can be controlled.

[0039] The light source may irradiate the plant with artificial light not only from the side of the plant but also from the top surface of the plant. The light source may irradiate the plant with artificial light from at least one of the side and the top surface. In other words, the light source may be placed on the side of the plant, on the upper vertical side, or both on the side and on the upper vertical side of the plant. From the viewpoint of space utilization efficiency, it is preferable to place the light source on both the side and the upper vertical part of the plant body.

[0040] The light source is not particularly limited and can include, for example, semiconductor light sources such as LEDs (light-emitting diodes) and discharge lamps such as fluorescent lamps. From the viewpoint of suppressing heat generation from the light source and having excellent luminous efficiency, the light source is preferably an LED.

[0041] There may be one type of LED, or there may be two or more types. LEDs may emit visible light such as red, blue, or green, or they may emit ultraviolet light (wavelength 380 nm or less) or infrared light (wavelength 780 nm or more). In particular, LEDs that emit light in the wavelength range of 400nm to 700nm are preferred from the viewpoint of promoting photosynthesis in plants. Furthermore, increasing the fruit yield per plant is important in terms of improving energy efficiency and space utilization efficiency, and from this viewpoint, the combined use of red and blue LEDs is more preferable.

[0042] <Other configurations> The hydroponic cultivation apparatus 100 shown in Figure 1 is equipped with a light source 60, but the hydroponic cultivation apparatus according to this disclosure does not need to be equipped with a light source. The method may involve irradiating the plant with sunlight either directly or by guiding the light.

[0043] If the hydroponic cultivation apparatus according to this disclosure is equipped with a light source, it is preferable that it further includes a mechanism for controlling the light intensity and light-dark cycle of the light source.

[0044] Furthermore, although the hydroponic cultivation apparatus 100 shown in Figure 1 is equipped with a viewing window 50, the grasping means in the hydroponic cultivation apparatus according to this disclosure is not limited to the viewing window. Multiple means may also be combined.

[0045] For example, the monitoring means may be a pH meter, which measures the pH of the nutrient solution flowing through the pipe to understand the state of the nutrient solution. More specifically, if the pH of the nutrient solution changes beyond the acceptable range of pH fluctuations associated with changes in nutrient solution components corresponding to the normal growth of the plant being cultivated, it can be detected as an abnormality. The means of monitoring this condition may be an electrical conductivity meter, which measures the electrical conductivity of the nutrient solution flowing through the pipe to understand the state of the nutrient solution. More specifically, if the electrical conductivity of the nutrient solution changes beyond the permissible range of fluctuations in electrical conductivity associated with changes in the nutrient solution components corresponding to the normal growth of the plant being cultivated, this can be detected as an abnormality. The means of assessment may be an absorbance meter, and the state of the nutrient solution passing through the pipe can be determined by measuring the absorbance of the nutrient solution. More specifically, the accumulation of contaminants in the nutrient solution can be detected by measuring the absorbance at wavelengths characteristic of the contaminant components in the nutrient solution. The means of assessment may be a turbidimeter, and the condition of the nutrient solution passing through the pipe can be understood by measuring its turbidity. More specifically, by measuring the turbidity of the nutrient solution, an increase in insoluble contaminants can be detected. The means of assessment may be a viscometer, and the state of the nutrient solution flowing through the pipe can be determined by measuring its viscosity. More specifically, by measuring the viscosity of the nutrient solution, an increase in fouling components can be detected.

[0046] The hydroponic cultivation apparatus according to this disclosure preferably further includes a mechanism for controlling temperature, humidity, and carbon dioxide concentration.

[0047] Furthermore, a light-reflecting member may be provided at a position opposite the light source, with the plant body in between. Examples of light-reflecting members include reflectors and reflective sheets. The reflective sheet functions as an openable door.

[0048] [Hydroponic cultivation methods] The hydroponic cultivation method relating to this disclosure is a hydroponic cultivation method for cultivating fruit vegetables using the hydroponic cultivation apparatus relating to this disclosure, and includes the steps of removing the curved portion and the straight portion of the piping during or after the cultivation period of the fruit vegetables, and cleaning the straight portion of the piping and cleaning the curved portion of the piping, or replacing the curved portion of the piping with a new one.

[0049] The hydroponic cultivation method described herein is a method for cultivating fruit and vegetable crops using hydroponics.

[0050] Hydroponic methods are not particularly limited and include flooded hydroponics, thin-film hydroponics, spray hydroponics, and drip hydroponics, in which liquid fertilizer is dripped onto the roots or root support.

[0051] In this disclosure, "cultivation period" refers to the period from the start of planting to harvest. "Cultivation process" refers to the process during the cultivation period.

[0052] The start of the cultivation period is, for example, the point at which the plant seedlings obtained in the seedling raising process described later are planted in a predetermined position in the hydroponic cultivation apparatus according to this disclosure.

[0053] <Cultivation process> -Light / dark cycle- The cultivation process preferably includes a step of irradiating the plant with artificial light. During the cultivation process, temperature conditions can be adjusted by irradiating the plants with artificial light. For example, it is possible to adjust the temperature to two or more conditions, such as light-period temperatures and dark-period temperatures. From the viewpoint of cultivation efficiency and achieving high sugar content, the upper limit of the light-period temperature is preferably 29°C or lower, more preferably 28.5°C or lower, and even more preferably 28°C or lower. From the viewpoint of cultivation efficiency and sugar content, the lower limit of the light-period temperature is preferably 15°C or higher, more preferably 20°C or higher, and even more preferably 25°C or higher.

[0054] From the viewpoint of cultivation efficiency and sugar content, the upper limit of the dark period temperature is preferably 25°C or lower, more preferably 23°C or lower, and even more preferably 22°C or lower. From the viewpoint of cultivation efficiency and achieving high sugar content, the lower limit of the dark period temperature is preferably 10°C or higher, more preferably 13°C or higher, and even more preferably 15°C or higher.

[0055] Light and dark temperatures are measured by placing a thermometer 1 cm away from the plant. For example, the THA-3151 temperature and humidity sensor manufactured by T&D Corporation can be used as the thermometer.

[0056] In this disclosure, "light period" means the period during which light is irradiated onto the plant. In this disclosure, "dark period" means the period during which light is not irradiated onto the plant.

[0057] The method for controlling the light and dark temperatures is not particularly limited and can be carried out by conventionally known methods. For example, the light and dark temperatures can be controlled by monitoring them with the thermometer and, if necessary, supplying warm or cold air.

[0058] From the viewpoint of cultivation efficiency and increasing sugar content, the ratio of light period to dark period (light period / dark period) is preferably 0.5 to 5, more preferably 1 to 4, and even more preferably 1 to 3.

[0059] -Light intensity- From the perspective of cultivation efficiency and sugar content, the light intensity of artificial light irradiated onto plants during the cultivation process should be 200 μmol / m². 2 / s~800μmol / m 2 It is preferable that the value is / s, and 250 μmol / m³ 2 / s~600μmol / m 2 It is more preferable to use / s.

[0060] Light intensity is measured by positioning the light-receiving surface of the measuring instrument 1 cm away from the plant and facing the light source. For example, a quantum photonography sensor (LI-COR, LI-190R) can be used as the measuring instrument. If the light sources are positioned in two or more directions from the plant, the sum of the light intensities measured by positioning the measuring instrument towards each light source is used as the light intensity.

[0061] Light intensity can be controlled by changing the type and number of light sources used (LEDs, fluorescent lamps, etc.), changing the distance between the light source and the plant, or by using a dimmable light source.

[0062] -Relative humidity- From the viewpoint of cultivation efficiency and achieving high sugar content, the relative humidity during the cultivation process is preferably controlled to 50% to 80%, and more preferably to 55% to 77%.

[0063] Relative humidity is measured by placing a hygrometer 1 cm away from the plant. For example, the THA-3151 temperature and humidity sensor manufactured by T&D Corporation can be used as a hygrometer.

[0064] The method for controlling humidity is not particularly limited and can be carried out by conventionally known methods. For example, humidity conditions can be controlled by monitoring the humidity of the cultivation environment using the above-mentioned hygrometer and, if necessary, by using an air conditioning system that has humidifying and dehumidifying functions.

[0065] -Carbon dioxide concentration- From the viewpoint of shortening the period until harvest, the carbon dioxide concentration in the cultivation environment during the cultivation process is preferably 300 ppm to 5000 ppm, and more preferably 400 ppm to 3500 ppm.

[0066] Carbon dioxide concentration is measured by placing a carbon dioxide concentration meter 1 cm away from the plant. For example, the LI-850 manufactured by LI-COR can be used as a carbon dioxide concentration meter.

[0067] The method for controlling carbon dioxide concentration is not particularly limited and can be carried out by conventionally known methods. For example, it can be done by monitoring the carbon dioxide concentration in the environment using the carbon dioxide concentration meter mentioned above and using air conditioning equipment, etc., as needed.

[0068] <Pipe removal process> The hydroponic cultivation method described herein includes a step of removing the curved portion of the piping during or after the cultivation period for fruit and vegetable crops.

[0069] Specifically, in the hydroponic cultivation apparatus 100 shown in Figure 1, the curved pipe 42 is removed. For example, the curved pipe 42 can be removed by releasing the connection between the straight pipe 41 and the curved pipe 42.

[0070] The curved pipe 42 may be removed only once or more times during the cultivation period. The timing of the removal may be regular or irregular.

[0071] <Pipe cleaning and replacement process> The hydroponic cultivation method relating to this disclosure includes the steps of cleaning the straight portion of the piping and cleaning the curved portion of the piping, or replacing the curved portion of the piping with a new one.

[0072] Specifically, in the hydroponic cultivation apparatus 100 shown in Figure 1, the straight pipes 41 are cleaned, and the curved pipes 42 are either cleaned or replaced with new ones.

[0073] The method of cleaning the pipes is not particularly limited and may include using pipe cleaning brushes or the like.

[0074] <Washing timing determination process> The hydroponic cultivation method according to this disclosure preferably includes a step of determining the timing for cleaning the piping based on information obtained using a sensing means in the hydroponic cultivation apparatus according to this disclosure. Furthermore, based on the judgment result, it is preferable to remove the curved portion of the piping.

[0075] Specifically, in the hydroponic cultivation method using the hydroponic cultivation apparatus 100 shown in Figure 1, the timing for cleaning the straight pipe 41 is determined based on information obtained through the viewing window 50. When it is determined that it is time to clean the straight pipe 41, the curved pipe 42 is removed.

[0076] The system determines the timing for cleaning the pipes, and based on the determination, sets the cleaning or replacement schedule. This minimizes the number of cleaning or replacement cycles, thereby reducing damage to plants associated with pipe cleaning or replacement.

[0077] In the hydroponic cultivation method using the hydroponic cultivation apparatus 100 shown in Figure 1, the following methods can be used to determine the timing for cleaning the piping. The condition of the inner wall of the piping is checked periodically (for example, every day) through the viewing window 50. The procedure involves checking whether the proportion of the area on the inner wall of the pipe that is covered with foreign matter, within the area visible through the viewing window 50, is equal to or greater than a predetermined threshold (for example, 10%). If the above ratio exceeds a predetermined threshold, it is determined that it is time to clean the piping. If the above percentage is below a predetermined threshold, it is determined that it is not time to clean the pipes.

[0078] Examples of information obtained using the measurement methods include the pH, electrical conductivity, absorbance, turbidity, and viscosity of the nutrient solution.

[0079] Furthermore, when using a pH meter to measure the pH of the nutrient solution flowing through the piping, for example, it is necessary to check whether the pH is below a predetermined threshold (e.g., 4.5). If the pH is below a predetermined threshold, it is determined that it is time to clean the piping. If the pH is above a predetermined threshold, it is determined that it is not time to clean the piping.

[0080] Furthermore, when measuring the electrical conductivity of the nutrient solution flowing through the piping using an electrical conductivity meter, for example, it is necessary to check whether the electrical conductivity exceeds a predetermined range (for example, ±0.5 dS / m from a value considered appropriate based on the growth state of the plant). If the electrical conductivity is within a predetermined range, it is determined that it is time to clean the piping. If the electrical conductivity exceeds a predetermined range, it is determined that it is not time to clean the piping.

[0081] The same determination can be made when detecting contamination of the nutrient solution flowing through the pipes using other parameters such as absorbance.

[0082] As described above, thresholds may be set for each physical property of the nutrient solution, and it may be determined that it is time to clean the piping when the measured value falls outside the threshold. The hydroponic cultivation apparatus according to this disclosure may also be equipped with a sensor that notifies when the measured value falls outside the threshold.

[0083] <Seedling raising process> The hydroponic cultivation method relating to this disclosure may include a seedling cultivation step. In the seedling cultivation step, the plant body after germination is grown into a seedling.

[0084] From the standpoint of cultivation efficiency, seedling cultivation is preferably carried out by hydroponics, and more preferably by flooded hydroponics.

[0085] In the seedling cultivation process, it is preferable to switch between light and dark periods by irradiating the plants with artificial light after germination, and to adjust the temperature conditions during the light and dark periods. For example, it is possible to adjust to two or more temperature conditions, such as light temperature and dark temperature. From the viewpoint of shortening the period until bud formation, the upper limit of the light-period temperature is preferably 29°C or lower, more preferably 28.5°C or lower, and even more preferably 28°C or lower. From the viewpoint of shortening the period until bud formation, the lower limit of the light-period temperature is preferably 15°C or higher, more preferably 20°C or higher, and even more preferably 25°C or higher. From the viewpoint of shortening the period until bud formation, the upper limit of the dark period temperature is preferably 25°C or lower, more preferably 23°C or lower, and even more preferably 22°C or lower. From the viewpoint of shortening the period until bud formation, the lower limit of the dark period temperature is preferably 10°C or higher, more preferably 13°C or higher, and even more preferably 15°C or higher. Furthermore, the artificial light source, wavelength, etc., can be those specified in the cultivation process.

[0086] From the viewpoint of cultivation efficiency and achieving high sugar content, the ratio of light period to dark period (light period / dark period) is preferably 0.3 to 3, and more preferably 0.5 to 2.

[0087] From the viewpoint of cultivation efficiency and sugar content, the relative humidity during the seedling stage is preferably controlled to 50% to 80%, and more preferably to 55% to 77%.

[0088] From the perspective of cultivation efficiency and sugar content, the light intensity of artificial light irradiated onto the seedlings after germination during the seedling stage is 200 μmol / m². 2 / s~800μmol / m 2 It is preferable that the value is / s, and 250 μmol / m³ 2 / s~600μmol / m 2 It is more preferable to use / s.

[0089] Artificial light irradiation may be performed from above the plant body after germination, or from the side, but from the viewpoint of cultivation efficiency and space utilization efficiency, it is preferable to irradiate from above. Furthermore, artificial light may be irradiated from both the side and the top.

[0090] From the viewpoint of shortening the period until harvest, the carbon dioxide concentration in the environment during the seedling stage is preferably 300 ppm to 5000 ppm, and more preferably 400 ppm to 3500 ppm.

[0091] The duration of the seedling cultivation process is not particularly limited, but from the viewpoint of growth after transplanting and shortening the time until bud formation, it is preferably 5 to 40 days, more preferably 10 to 35 days, even more preferably 12 to 30 days, and particularly preferably 15 to 33 days.

[0092] When the seedling cultivation process is carried out using hydroponics, the support structure for supporting the plants after germination is not particularly limited, but it is preferable to use a material that has both appropriate water permeability and water retention properties, and more preferably, a support stand equipped with a urethane sponge, phenolic resin sponge, rock wool, or a water-retaining sheet.

[0093] <Germination Process> The hydroponic cultivation method relating to this disclosure may include a germination step. In the germination step, the seeds of the plant to be used in the germination step are germinated.

[0094] The germination method is not particularly limited and can be carried out by conventionally known methods. For example, it can be carried out by sowing plant seeds on a support that has been thoroughly moistened with water and storing it in a dark place. Examples of suitable supports include those used in the seedling cultivation process.

[0095] Furthermore, it is preferable to select seeds from plant bodies that have germinated that are at a similar stage of growth and raise them as seedlings. This allows for a uniform harvest time for the fruits and improves cultivation efficiency.

[0096] The temperature required for germination varies depending on the type and variety of plant used, but for commercially available seeds, this is generally disclosed as the germination temperature. If the germination temperature is unknown, it can also be determined experimentally. Furthermore, some plant types and varieties require dormancy breaking or other treatments for germination. Some seeds require specific wavelengths of light for germination, others require complete darkness, and some will germinate in either condition. These requirements, like germination temperature, can also be determined.

[0097] The relative humidity during the germination process is preferably 70% to 100%, and particularly preferably 80% to 95%. Maintaining this range prevents the plant from drying out during the germination period, thus promoting good growth.

[0098] The duration required for germination is not fixed, but it is preferably the period from root development to the start of hypocotyl elongation, and is generally several days to about a week. By dedicating this period to germination, the roots can grow sufficiently, while excessive hypocotyl elongation can be avoided, resulting in better seedling growth during the subsequent nursery stage and a shorter time to flowering, which is therefore preferable. [Examples]

[0099] The above embodiments will be described in detail below with reference to examples, but the above embodiments are not limited to these examples.

[0100] <Example 1> (Germination process) Tomato seeds (variety: Momotaro York (registered trademark), manufactured by Takii Seed Co., Ltd.) were sown on a support (a rectangular parallelepiped foamed polyurethane of 5 cm × 5 cm × 2 cm) sufficiently containing pure water, and stored for 3 days in a dark environment at a temperature of 28°C and a relative humidity of 70% to germinate and obtain tomato plants.

[0101] (Seedling raising process) The tomato plants obtained in the above germination process were transplanted into a hydroponic cultivation device equipped with an artificial light irradiation device and a culture solution tank containing a nutrient solution, and seedlings were raised for 20 days by the deep flow technique.

[0102] (Cultivation process) Ten plants obtained in the seedling raising process were planted in the hydroponic cultivation device shown in FIG. 1 and cultivated under the following cultivation conditions. After the flowering of the third inflorescence stage was confirmed, pinching was performed leaving the upper two leaves of the same inflorescence stage. The number of fruits set in each fruit cluster was set to 4 fruits, and when there was excessive fruit setting, they were removed before the fruit diameter exceeded 2 cm. Thereafter, management was continued, and the fruits set in the first to third fruit cluster stages were sequentially harvested and evaluated. In FIG. 1, five light sources are arranged at equal intervals along a direction parallel to the gravitational direction, but in the example, there are 10. Further, a reflection sheet, which is an example of a light reflection member, was provided at a position facing the light source with the tomato plants interposed therebetween. -Cultivation conditions- ·Light-dark cycle (light period / dark period): 16 hours / 8 hours ·Light intensity: 500 μmol / m 2 / s ·Temperature: 27°C (light period) / 19°C (dark period) ·Humidity: 70% ·Carbon dioxide concentration: 1000 ppm ·Liquid fertilizer: Hyponica A solution, B solution

[0103] The nutrient solution used from the time of planting until the flowering of the third inflorescence was a dilution of the above liquid fertilizer with pure water so that the electrical conductivity was 1.2 ds / m (pH 4.8). Subsequently, for the period until the end of cultivation, the above liquid fertilizer was diluted with pure water to achieve an electrical conductivity of 4.0 ds / m (pH 4.7). If the water level in the nutrient solution tank fell below a certain value due to nutrient absorption by plants, pure water was supplied to the tank. In addition, an electrical conductivity meter was installed in the nutrient solution tank, and the electrical conductivity was measured continuously. When the electrical conductivity fell below the above value, equal amounts of Hyponica A solution and B solution were automatically added, thereby controlling the concentration of the nutrient solution based on electrical conductivity. No special control measures were taken regarding pH.

[0104] After planting, the condition of the piping was visually inspected through the viewing window at least once a week. If an accumulation of dirt was observed and it was determined that it was time to clean the piping, the circulation of the nutrient solution was temporarily stopped, the curved pipe was removed, and the dirt inside the pipe was removed. After that, the curved pipe was connected to the straight pipe, and the circulation of the nutrient solution was resumed. Furthermore, the timing for cleaning the pipes was determined to be 1 to 2 times per month.

[0105] After each cultivation period, all piping was removed, dirt was cleaned from inside the pipes, and the cultivation tanks and nutrient solution tanks were cleaned.

[0106] A period of 125 days after sowing and 105 days after transplanting was defined as "one crop." This same cultivation method was repeated four more times to form five crops. Table 1 shows the fruit yields from the first to the fifth crops. The pH of the nutrient solution was measured at the end of each cultivation period.

[0107] <Example 2> Cultivation was carried out in the same manner as in Example 1, except that the curved pipes were removed regularly once a week after planting to remove any dirt from inside the pipes.

[0108] <Comparative Example 1> A hydroponic cultivation system similar in configuration to the one shown in Figure 1 was used, except that the piping connecting the nutrient solution tank, cultivation tank, and liquid delivery mechanism consisted of straight and curved pipes that could not be separated. After each cultivation period, the cultivation tanks and nutrient solution tanks were cleaned. Because the curved piping could not be removed, the inside of the piping was not cleaned.

[0109] [Average yield] The average mass of fruit harvested per plant was calculated and used as the average yield. The evaluation results are shown in Table 1.

[0110] [Table 1]

[0111] As shown in Table 1, in Examples 1 and 2, it was found that high yields of fruit could be obtained from the first to the fifth crop. On the other hand, in Comparative Example 1, it was found that the fruit yield decreased with each subsequent crop. [Explanation of symbols]

[0112] 10 Nutrient solution tanks 21 Cultivation tank 22 Lid 30. Fluid delivery mechanism 41 Straight Piping 42 Curved piping 43 Discharge pipe 50 Peephole 60 light source 80 Plants 100 Hydroponic Growing Systems

Claims

1. Nutrient solution tank and A cultivation tank for growing plants, A liquid supply mechanism that sends nutrient solution from the nutrient solution tank to the cultivation tank, The nutrient solution tank, the cultivation tank, and the liquid supply mechanism are connected to each other by piping, Means for understanding the state of the nutrient solution flowing through the pipe and the state of at least one of the inner walls of the pipe, Equipped with, The aforementioned piping has a straight section and a curved section. At least a portion of the curved section of the aforementioned piping is formed of a flexible, soft material. The curved portion of the piping and the straight portion of the piping are detachably connected. A hydroponic system used for cultivating fruits and vegetables.

2. As a means of understanding the aforementioned state, the piping is equipped with a viewing window, The hydroponic cultivation apparatus according to claim 1, wherein a removable light-shielding member is provided on the outside of the viewing window.

3. The hydroponic cultivation apparatus according to claim 1, wherein the aforementioned fruit vegetables are plants of the Solanaceae family or plants of the Cucurbitaceae family.

4. The hydroponic cultivation apparatus according to claim 1, further comprising a light source that irradiates the plant body with artificial light from at least one of its side and top surfaces.

5. A hydroponic cultivation method for cultivating fruit and vegetable crops using a hydroponic cultivation apparatus described in any one of claims 1 to 4, The process of removing the curved portion of the piping during or after the cultivation period of the aforementioned fruit and vegetable crops, The straight section of the aforementioned piping is cleaned, and, A hydroponic cultivation method comprising the steps of cleaning the curved portion of the piping or replacing the curved portion of the piping with a new one.

6. A hydroponic cultivation method for cultivating fruit and vegetable crops using a hydroponic cultivation apparatus described in any one of claims 1 to 4, A step of determining the timing for cleaning the piping based on information obtained using the means for understanding the aforementioned state, Based on the determination result, the process involves removing the curved portion of the piping during or after the cultivation period of the fruit and vegetable crops, The straight section of the aforementioned piping is cleaned, and, A hydroponic cultivation method comprising the steps of cleaning the curved portion of the piping or replacing the curved portion of the piping with a new one.

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