JP6729763B2 - Hydroponic cultivation device and plant cultivation method - Google Patents

Description

The present invention relates to a hydroponic cultivation apparatus for supplying a nutrient solution to a crop to grow a plant in greenhouse cultivation, and a cultivation system using the hydroponic cultivation apparatus.

In house cultivation, in order to cultivate plants efficiently, it is necessary to more accurately grasp and control the cultivation environment, but even now, many cultivation methods are based on past experience, A cultivation method is adopted in which production is performed in consideration of temperature, humidity, sunshine duration and the like.

However, none of them are sufficient, and it has not yet been made clear to prepare a proper cultivation environment. Among these, control of the absorption rate of water and nutrients, photosynthesis, etc. is one that has not been properly controlled and analyzed, although it is known to affect cultivated crops.

The transpiration amount can be measured for each leaf unit of the plant using a transpiration amount measuring device or the like. Commercially available evaporation measuring devices include photosynthetic evaporation measuring device LI-6400 (Meiwa Forsys Co., Ltd.), photosynthetic evaporation measuring device LCpro-SD (EKO Hidehiro Seiki Co., Ltd.), portable photosynthetic evaporation measuring device CIRAS-3 ( TM Systems Co., Ltd.) and others.

However, according to these transpiration amount measuring devices, even if it is possible to measure the transpiration amount in leaves of individual units, it is not possible to accurately measure the transpiration rate of the entire plant while actually growing it in the house. Can not.

For example, in Japanese Patent Laid-Open No. 2004-000146 as a cultivation technique using such a measuring device, in order to make a plant a cultivation environment close to an ideal one, based on each data such as temperature, humidity, and transpiration amount of leaves, A technique using a sensor for detecting a growing state of a plant is disclosed (claim 19, 0008 paragraph, 0032 paragraph, 0079 paragraph).

However, although the sensor that detects the growing state can detect the body temperature of the plant, the surface temperature of the leaves, the transpiration of the leaves, etc., even if this data is converted into the entire environment in the house, It is difficult to convert the transpiration rate of all the plants actually cultivated in Indonesia into real time data.

Japanese Unexamined Patent Publication No. 2015-008699 discloses a processing method in which the state of transpiration of a plant is determined by measuring the time change of the temperature of the cultivation space, and the growth state of the plant is measured. However, although it is possible to judge whether the plant group to be cultivated is transpiring or not, it is difficult to measure the transpiration rate without a time lag.

Japanese Unexamined Patent Application Publication No. 2003-219741 discloses a method for measuring a liquid supply amount for supplying a nutrient solution to a hydroponic bed and a drainage amount discharged from the culture bed in a conventional hydroponic culture. .. However, since this measurement method is a batch-type measurement method in which the nutrient solution is replenished when the amount of the nutrient solution decreases to some extent, the timing at which the plant being cultivated actually evaporates and the measured transpiration There is a problem that the time for plotting the amount is deviated, the transpiration rate cannot be accurately measured, and the environment in the greenhouse cultivation cannot be controlled in a timely manner.

JP 2004-000146 A JP, 2005-008699, A JP, 2003-219741, A

It is an object of the present invention to solve these problems and provide a hydroponic cultivation apparatus capable of accurately measuring the transpiration rate of a cultivated crop, and a cultivation system using the hydroponic cultivation apparatus.

The nutrient solution cultivation apparatus of the present invention comprises a cultivation bed tank, a nutrient solution tank, a device for supplying the nutrient solution from the nutrient solution tank to the cultivation bed tank, and the nutrient solution discharged from the cultivation bed tank. A recovery device for returning to the liquid tank, a liquid supply device for supplying the liquid into the nutrient solution tank so that the amount of the liquid in the nutrient solution tank becomes a prescribed amount, and a liquid supply to the nutrient solution tank by the liquid supply device. A liquid supply speed measuring device for measuring the speed for each predetermined time is provided, and the predetermined time is 30 minutes or less.

The cultivation system of the present invention is a plant cultivation system provided with such a hydroponic cultivation apparatus of the present invention, and uses the measured values of the liquid feeding rate measured by the liquid feeding rate measuring device to set the environment in the greenhouse cultivation. It is provided with environment control means for controlling.

In the process of supplying the nutrient solution from the nutrient solution tank to the cultivation bed tank, returning the nutrient solution discharged from the cultivation bed tank to the nutrient solution tank, and cultivating the plant in the cultivation bed tank, the nutrient solution tank is evaporated by the plants. The liquid inside is about to decrease. The liquid is supplied to the nutrient solution tank by the liquid supply device by the reduced amount.

In the present invention, by measuring the liquid supply rate of the liquid to the nutrient solution tank by the liquid supply apparatus at intervals of 30 minutes or less, the transpiration rate of the plant can be accurately measured with almost no time lag. Based on the transpiration rate measured by this hydroponics device, it is possible to accurately know the absorption rate of water and nutrients, the photosynthetic activity state of leaves, and the like.

This allows more appropriate environmental control in greenhouse cultivation.

Knowing the absorption rate of water and nutrients in greenhouse cultivation is important for managing cultivation. By appropriately controlling the absorption rate of water and nutrients, the quality of cultivated plants can be improved.

Environmental control of plant to be cultivated, such as temperature, humidity, solar radiation, CO ₂ concentration, EC of nutrient solution, pH of nutrient solution, water temperature, etc., based on accurate measurement data of transpiration rate of plant It also becomes possible to establish integrated environmental control technology for cultivation in greenhouses.

It is a typical sectional view of the device of the present invention. It is a typical sectional view explaining the measurement principle by the device of the present invention. It is a top view of the hydroponics device which concerns on embodiment. It is the IV-IV sectional view taken on the line of FIG. It is sectional drawing which shows an example of a cultivation pot. It is a graph which shows the measurement result in an Example.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is an explanatory view schematically showing the hydroponics device of the present invention. FIG. 2 is a conceptual diagram of the measurement of the transpiration amount, and shows a configuration in which the liquid supply device 5 and the liquid supply speed measuring device 6 are omitted from FIG.

The nutrient solution cultivation device of FIG. 1 according to an aspect of the present invention includes at least a cultivation bed tank 1, a nutrient solution tank 2, a device 3 for supplying a nutrient solution from the nutrient solution tank 2 to the cultivation bed tank 1, and the cultivation. To the nutrient solution tank 2, a recovery device 4 for returning the nutrient solution discharged from the bed tank 1 to the nutrient solution tank 2, a liquid supply device (ball tap in this example) 5 for supplying the nutrient solution or water to the nutrient solution tank 2. A liquid supply speed measuring device (a flow meter in this example) 6 for measuring the liquid supply speed is provided.

Since the amount of water evaporated in the process of supplying and collecting the liquid to the cultivation bed tank 1 is significantly smaller than the amount of transpiration, the decrease amount of the nutrient liquid in the nutrient liquid tank 2 is as shown in FIG. Is absorbed from the root area of the plant, flows through the crop, and is approximately equal to the amount transpired from the crop into the atmosphere. Therefore, the transpiration amount is measured by measuring the decrease amount of the liquid in the nutrient solution tank 2.

The method for measuring the amount of decrease in the liquid in the nutrient solution tank 2 is not particularly limited, but instead of directly measuring the amount of the nutrient solution in the nutrient solution tank, as shown in FIG. A liquid supply device 5 such as a ball tap is used so that the liquid level always becomes a fixed value (specified value), and the amount of the nutrient solution supplied to the nutrient solution tank 2 through the liquid supply device 5 is measured by a liquid supply speed measuring device 6 It is possible to accurately measure the amount of transpiration from the cultivated crop by measuring with.

To measure the liquid supply rate, you can use a flow meter that can measure continuously, and record the data at regular intervals. The speed may be measured.

It is important to measure the liquid supply rate at intervals of 30 minutes or less, preferably at intervals of 15 minutes or less, more preferably at intervals of 10 minutes or less, and at intervals of 5 minutes or less. Is more preferable, and measurement at intervals of 3 minutes or less is particularly preferable. The lower limit of the measurement interval of the liquid supply speed is not particularly specified, but the shorter the measurement interval, the better. Since the shorter the measurement interval is, the more expensive the equipment and the running cost are, the measurement interval is longer than 0 second, preferably 0.1 second or more, and particularly preferably 1 second or more.

Since the nutrient solution is supplied to the nutrient solution tank 2 so that the amount of the solution in the nutrient solution tank 2 becomes a specified amount, by measuring the feeding rate to the nutrient solution tank 2 at intervals of 30 minutes or less, It is possible to measure the transpiration rate of a plant cultivated in the cultivation bed tank 1 supplied from the nutrient solution tank 2 with almost no time lag.

The liquid supply speed means the amount of liquid supplied per unit time (unit is, for example, L/min, L/sec, etc.).

For example, in the case where the liquid supply amount is measured once a minutes, and the measured liquid supply amount is b(L), b/L of the nutrient solution tank 2 is kept for a minute until the next measurement. It is calculated that the liquid is supplied at a rate of a (L/min). Therefore, the shorter the measurement interval a, the higher the measurement accuracy of the liquid supply rate, but it is possible to appropriately set the appropriate measurement interval in accordance with the size of the plant area for cultivation. Considering the flow rate fluctuation, the measurement accuracy of the sufficiently high liquid supply rate can be obtained once every 30 minutes or less, and the transpiration rate of the crop can be accurately measured.

3 and 4 show a tomato hydroponics system according to an embodiment of the present invention. FIG. 3 is a plan view and FIG. 4 is a sectional view taken along line IV-IV of FIG.

In FIG. 3, a plurality of cultivation bed tanks 10 are arranged in a row in a house (four rows in the figure) to form a cultivation bed tank group 20, and a plurality of cultivation bed tanks 20 are installed in parallel.

The cultivation bed tank 10 is formed into a shape (for example, a gutter shape or a box shape) having walls in all directions of about 20 m in length, about 30 cm in width, and about 10 cm in height that prevents water from leaking by foam molding. A waterproof sheet is laid on the inner wall surface, and a groove 11 (FIG. 4) is formed over the entire length in the longitudinal direction at the center of the bottom surface. A plurality of cultivation pots 12 are placed on the cultivation bed tank 10 at intervals in the longitudinal direction of the cultivation bed tank 10. In this embodiment, about 200 cultivation pots 12 are arranged in one cultivation bed tank 10, but the number is not limited to this.

The cultivation pot 12 is formed of a synthetic resin such as polyethylene in a cylindrical shape with a bottom, and an opening 13 having a shape of, for example, a circle, an ellipse, a quadrangle, or the like is formed at the bottom thereof. The size of the cultivation pot 12 is appropriately determined, but is usually about 6 to 15 cm in diameter and about 6 to 15 cm in height.

The opening 13 of the cultivation pot 12 is covered with a water-permeable sheet-shaped member 14, and the nutrient solution flowing in the cultivation bed tank 10 penetrates into the cultivation pot 12. In this embodiment, the sheet-shaped member 14 is formed of a mesh that allows the nutrient solution to pass through and does not allow the roots of the plant to pass through. The sheet-shaped member 14 may be fixed to the inner bottom surface of the pot 12 or may be fixed to the outer bottom surface of the pot 12.

The cultivation pots 12 are filled with a plant support 15 having a function of absorbing and retaining a nutrient solution, such as a medium and rock wool such as fine cotton, and one tomato seedling is planted in each cultivation pot 12. Has been done.

A top plate 16 made of a foamed synthetic resin board such as styrofoam is placed on the upper surface of the cultivation bed tank 10 over substantially the entire length of the cultivation bed tank 10 so as to cover the upper surface.

The top plate 16 is provided with a plurality of holes 16a at predetermined intervals in the longitudinal direction, and one cultivation pot 12 is inserted into each hole 16a so as to fit without gaps. There is. The bottom diameter of the cultivation pot 12 is larger than the width of the groove portion 11, and the cultivation pot 12 is placed on the bottom surface of the cultivation bed tank 10 with the opening 13 of the bottom portion positioned on the groove portion 11 and straddling the groove portion 11. It is placed.

Each of the cultivation bed tanks 10 is installed with a gradient of about 1/200 so as to have a flowing water gradient from one end to the other end in the longitudinal direction.

The nutrient solution circulation supply system for circulating and supplying the nutrient solution to each of the cultivation bed tanks 10 will be described below.

As described above, in FIG. 3, the plurality of cultivation bed tanks 10 are arranged in a plurality of rows (four rows in the drawing) to form the cultivation bed tank group 20, and the plurality of cultivation bed tank groups 20 are installed in parallel. One sub-tank 33 is attached to one cultivation bed tank group 20.

The hydroponics system has a parent tank 26 for storing the nutrient solution. Liquid fertilizer and water are supplied to the parent tank 26 from the pipes 24 and 25 equipped with the supply control valves 24a and 25a to prepare a nutrient solution having a predetermined concentration. The nutrient solution having a predetermined concentration prepared in the parent tank 26 is distributed and supplied to each child tank 33 via the pump 27, the pipe 28, the three-way valve 29, the flow meter 30, and the ball tap 31. A water supply pipe 32 is connected to the three-way valve 29, and water is supplied from the pipe 32 to the child tank 33 by switching the three-way valve 29.

The liquid in the child tank 33 is supplied to each cultivation bed tank 10 via the pump 34, the pipe 35, and the valve 36.

By supplying and storing the nutrient solution prepared in the parent tank 26 to the child tank 33, the nutrient solution having a uniform concentration prepared in the parent tank 26 can be always supplied to each cultivation bed tank 10. ..

In FIG. 3, the nutrient solution used in one cultivation bed tank group 20 is returned to the child tank 33 of the cultivation bed tank group 20 through the pipe 37, and the nutrient solution is circulated. The nutrient solution or water from the pipe 32 is additionally supplied to the child tank 33 by the ball tap 31 so that the liquid level of the nutrient solution in the child tank 33 is maintained constant.

When supplying the nutrient solution to the cultivation bed tank 10, the nutrient solution is caused to flow at a flow rate of about 3 to 10 liters per minute, and a water depth of about 5 to 50 mm is constantly maintained from the bottom surface of the cultivation bed tank 10 to provide a cultivation pot. It is preferable to supply at a flow rate so that the lower part of 12 is immersed. The nutrient solution supplied into the cultivation bed tank 10 flows into the inside through the sheet-shaped member 14 from the opening 13 of each cultivation pot 12, so that the nutrient solution is supplied to the rhizosphere in the lower part of the cultivation pot 12. A phase is formed. The nutrients are absorbed from the nutrient solution by the roots of the tomato plants, and the nutrient solution constantly supplied into the cultivation bed tank 10 constantly supplements the nutrients in the cultivation pot 12.

The flow rate of the nutrient solution or water supplied from the parent tank 26 or the pipe 32 to each child tank 33 is measured by the flow meter 30. The detection signal of the flow meter is input to the control device (not shown). The controller obtains the amount of transpiration from the crop in each cultivation bed tank group 20 based on this flow rate signal. Since the amount of water evaporated from the upper surface of the cultivation pot 12 and the steps of supplying and collecting the liquid to the cultivation bed tank group 20 is significantly smaller than the amount of transpiration from each crop, the liquid level in the child tank 33 is always By measuring the amount of nutrient solution or water supplied to the child tank 33 via the ball tap 31 so as to be a fixed position (specified value) with the flow meter 30, the amount of transpiration from the cultivated crop is accurately measured. .. Crop cultivation can be managed based on the transpiration amount thus obtained. For example, the temperature, humidity, solar radiation amount, CO ₂ concentration, EC of the nutrient solution, PH of the nutrient solution, water temperature, switching of the three-way valve 29, and water supply amount of the pump 34 are controlled in the house.

In the latter stage of cultivating leaf vegetables and fruit vegetables cultivated in each cultivation bed tank group 20, the child tank 33 and the cultivation bed tank 10 are switched by switching the supply of the nutrient solution from the pipe 28 to the water supply from the pipe 32. The fertilizer concentration of the circulating nutrient solution can be reduced. As a result, in the latter stage of cultivation, the amount of nitric acid in the plant can be gradually reduced, and leaf vegetables and fruit vegetables can be harvested with the amount of nitric acid reduced.

When the nitric acid in the plant is taken up by the human body, it combines with amide nitrogen to form nitrosamine. By lowering the fertilizer concentration of the nutrient solution in the latter stage of cultivation, the concentration of nitric acid in the plant can be reduced. Also, by reducing the concentrations of nitrogen, phosphoric acid, and potassium in the nutrient solution used in the latter half of the cultivation, the environmental load can be significantly reduced even when the nutrient solution is discarded after the harvest is completed. You can

As the above-mentioned sheet-shaped member 14, various members can be used as long as they have a mesh that allows the nutrient solution to pass therethrough and does not allow the roots of the plant to be cultivated to pass. It is preferable to use a woven fabric having a weft density of 120 (pieces/inch) and a weft density of 70 to 120 (pieces/inch). Such a woven fabric has excellent strength even when used in a nutrient solution for a long period of time. As such a woven fabric, a taffeta woven fabric made of thermoplastic fibers is preferable, and a taffeta woven fabric made of filament yarn made of thermoplastic fibers is more preferable. Specifically, a sheet made of taffeta woven polyester is preferable. Used for.

As a means for integrating the sheet-shaped member 14 into the cultivation pot 12, adhesion with an adhesive, heat welding, or the like can be used. However, if the sheet-shaped member 14 is integrated by heat welding, the sheet-shaped member can be immersed in the nutrient solution for a long period of time. Is not easily peeled off from the pot, and the adhesive strength and durability are maintained, which is preferable.

Further, in the present invention, a fixed reinforcing member can be used when the sheet-shaped member is integrated with the pot by means such as adhesion or heat welding. In this case, the sheet-shaped member is integrated with the fixed reinforcing member in the pot. Be converted. For example, one or a plurality of fixing reinforcing members can be partially provided on a portion where the sheet-shaped member and the pot are integrated (fixing portion (adhesive portion, welding portion, etc.)), and the entire fixing portion can be provided. A fixed reinforcing member may be provided over the entire length. In this embodiment, the sheet-shaped member is fixed to the pot by using the fixing and reinforcing member at a part or the whole of the periphery of the opening. By providing the fixing and reinforcing member, it becomes difficult for the nutrient solution to permeate the fixing portion between the sheet-shaped member and the cultivation pot, so that the adhesive strength can be maintained for a long period of time. In addition, when the sheet-shaped member is difficult to heat-weld to the cultivation pot, good welding strength can be obtained by heat-welding the fixed reinforcing member to the pot through the mesh of the sheet-shaped member. This allows the pot to be used repeatedly, in addition to the complete root zone limiting effect.

Further, in order to maintain good welding strength, it is preferable to increase the number of resin welding portions (portions that actually melt in the resin pool) for welding, and for that purpose, make the thickness of the ring as large as possible. Is preferred. It is particularly preferable that the welding strength is about 30 kg/cm ² .

The material of the fixing and reinforcing member may be the same as or different from the material of the cultivation pot when they are bonded with an adhesive. When heat welding is performed using the fixed reinforcing member, the fixed reinforcing member is preferably made of the same material as the pot or a material having a melting point close to that of the pot for cultivation.

As in the pot 12 ′ shown in FIG. 5, the fixing portions of the sheet-shaped member 14 and the pot 12 ′ can be fixed by being sandwiched by the fixing reinforcing member 18 at the whole or part of the periphery of the opening 13. As an example of such a mode, a recess is provided in the peripheral portion of the opening 13 of the pot 12', and the sheet-shaped member 14 is fixed by sandwiching the sheet-shaped member 14 in the recess. be able to.

When fixing with an adhesive, an adhesive is applied and fixed between the sheet-shaped member and the pot and between the sheet-shaped member and the fixing and reinforcing member. When fixing by heat welding, for example, a sheet-shaped member is placed on the pot so as to block the opening, the fixing and reinforcing member is heat-welded, and the welded portion is pressed against the sheet-shaped member to form a sheet-shaped member. The fixed reinforcing member can be heat-welded to the pot through the mesh of the member.

The following are the experimental results showing the results of accurately measuring the liquid feeding rate and the transpiration rate from the leaves, which were measured in one example of the present invention. In this example, instead of actually measuring the transpiration rate from the leaves, the transpiration flow of the stem was measured, and this value was regarded as the transpiration rate from the leaves.

<Example 1>
Using the system of FIGS. 3 and 4, tomatoes were cultivated under the following conditions, and the transpiration rate and the liquid feeding rate were measured and compared. In addition, only one cultivation bed tank group 20 was used. The cultivation bed tank group 20 is composed of four rows of cultivation bed tanks 10, and 200 tomatoes are arranged in one cultivation bed tank 10.
・Size of cultivation bed tank 10: length 20 m, width 30 cm, height 10 cm
・Cultivated crops: tomato (800 strains)
・Capacity of child tank 33: 500 L
・Flowmeter 30: "VN05" manufactured by Aichi Clock Electric Co., Ltd.
Evaporation flow meter (Sap flow meter): "Sap Flow Logger Flow-4" manufactured by DYNAMAX. Attach to any two tomato stalks in each cultivation bed tank 10.
・Data measurement interval: 1 minute

FIG. 6 shows the liquid supply rate (liquid supply amount per hour per one pot) based on the measurement value of the flow meter 30 and the transpiration flow measured by the sap flow meter in greenhouse cultivation using this device. .. As shown in FIG. 6, it can be seen that the liquid supply rate based on the measurement value of the flow meter 30 and the transpiration flow measured by the Sapp flow meter substantially match. Therefore, it was confirmed that the transpiration rate from the plant can be accurately detected based on the feed rate measurement data of the nutrient solution by the flow meter, without using the Sapp flow meter.

1,10 Cultivation bed tank 2 Nutrient solution tank 5 Liquid supply device 6 Liquid supply speed measuring device 12,12' Cultivation pot 20 Cultivation bed tank group 26 Parent tank 29 Three-way valve 30 Flowmeter 31 Ball tap

Claims (3)

Cultivation bed tank,
A nutrient solution tank,
An apparatus for supplying a nutrient solution from the nutrient solution tank to the cultivation bed tank,
A recovery device for returning the nutrient solution discharged from the cultivation bed tank to the nutrient solution tank,
A liquid supply device for supplying a liquid into the nutrient solution tank so that the amount of the solution in the nutrient solution tank becomes a prescribed amount,
A nutrient solution cultivating device comprising a liquid supply rate measuring device for measuring a liquid supply rate to a nutrient solution tank by the liquid supply device at predetermined time intervals ,
A plurality of cultivation bed tank groups in which a plurality of the cultivation bed tanks are arranged are installed, and the liquid supply speed measuring device is provided for each cultivation bed tank group. .. A parent tank in which liquid fertilizer and water are supplied to prepare a nutrient solution, and a child tank corresponding to the nutrient solution tank in which the nutrient solution prepared in the parent tank is supplied are provided. The hydroponic cultivation apparatus according to 1. It is a cultivation method of the plant using the nutrient solution cultivation device of Claim 1 or 2, Comprising: Based on the liquid supply rate measurement data of the nutrient solution to the said nutrient solution tank measured by the said solution supply rate measuring device. A method for cultivating a plant, which comprises detecting a transpiration rate of the plant cultivated in the cultivation bed tank.

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