JP7571605B2 - Nutrient solution cultivation system and nutrient solution cultivation method - Google Patents

Description

The present invention relates to a hydroponic cultivation system for plants and a hydroponic cultivation method using this system.

In recent years, attempts have been made to cultivate leafy and fruit vegetables using hydroponic cultivation methods that use nutrient solutions. Hydroponic cultivation has the advantage of being able to produce vegetables stably without being affected by the weather, not being limited to certain cultivation locations, and allowing for cultivation with minimal fertilizer runoff.

One hydroponic cultivation device has a cultivation bed that is inclined to create a water flow gradient, a nutrient solution tank that stores nutrient solution, a supply line with a pump that supplies nutrient solution from the nutrient solution tank to the cultivation bed, and a return line that returns the nutrient solution from the cultivation bed to the nutrient solution tank (Patent Document 1).

The bottom surface of the cultivation bed in Patent Document 1 is provided with a convex member extending in the direction of the flow gradient, and the seedling root ball is placed on the convex member. The nutrient solution flows down along the side part of the convex member and does not directly contact the seedling root ball. This prevents the culture medium in the seedling root ball from being washed away by the nutrient solution.

In the nutrient solution cultivation system of Patent Document 1, a hydrophilic sheet is laid to cover the bottom surface of the cultivation bed and the protruding members, and the nutrient solution is allowed to soak into the hydrophilic sheet. This allows the medium part of the seedling root ball to also be soaked with the nutrient solution, allowing the plant to grow.

JP 2017-104023 A

In a hydroponic cultivation system that uses a hydrophilic sheet, tasks such as installing, removing, cleaning, and disinfecting the hydrophilic sheet are required.

The objective of the present invention is to provide a hydroponic cultivation system and cultivation method that can efficiently cultivate plants without using a hydrophilic sheet.

The gist of the present invention is as follows:

[1] A hydroponic cultivation system having a cultivation bed and a cultivation bench,
The cultivation bench has a slope on the upper surface,
The cultivation bed is installed on the upper surface of the cultivation bench, so that the bottom surface of the cultivation bed has a slope;
A convex stripe extending in a gradient direction is provided on a bottom surface of the cultivation bed, and an upper surface of the convex stripe is substantially horizontal;
A hydroponic cultivation system characterized in that a dam for storing nutrient solution is provided in the cultivation bed so that the upper surfaces of the protrusions are submerged in the nutrient solution.

[2] A hydroponic cultivation system according to [1], in which the difference between the level of the nutrient solution stored by the weir and the level of the upper surface of the ridge is 1 to 10 mm.

[3] A hydroponic cultivation system according to [1] or [2], in which the ridges are provided in multiple rows.

[4] A hydroponic cultivation system according to any one of [1] to [3], in which a waterproof sheet is provided to cover the bottom surface of the cultivation bed, but no hydrophilic sheet is provided.

[5] A hydroponic cultivation system according to any one of [1] to [4], comprising a planting panel plate having a plurality of planting holes arranged on the cultivation bed, each planting hole being positioned above the ridge.

[6] A hydroponic cultivation method using any one of the hydroponic cultivation systems [1] to [5].

[7] A method of hydroponics using the hydroponics system of [5], in which the seedling root balls are placed on the ridges through the planting holes in the planting panel, and the lower part of the seedling root ball is immersed in the nutrient solution stored in the cultivation bed to cultivate the plants.

The hydroponic cultivation system and cultivation method of the present invention does not require laying a hydrophilic sheet on the cultivation bed, eliminating the need for tasks such as installing, removing, cleaning, and disinfecting the hydrophilic sheet, and allowing plants to be cultivated efficiently.

FIG. 2 is a cross-sectional perspective view of a cultivation bed of the nutrient solution cultivation system according to the embodiment. FIG. 2 is a cross-sectional view of the cultivation bed taken along line II-II in FIG. FIG. 2 is a cross-sectional view of the cultivation bed taken along line III-III in FIG. FIG. 2 is a cross-sectional perspective view of a cultivation bed. FIG. 1 is a schematic plan view of a hydroponic cultivation system.

The following describes an embodiment with reference to Figures 1 to 5. In the present invention, the "nutrient solution" is not particularly limited as long as it is water used for plant cultivation, but it is preferable that the "nutrient solution" is water that contains any fertilizer component such as nitrogen, phosphoric acid, or potassium.

As shown in FIG. 1, this hydroponic cultivation system 1 has a cultivation bed 2 and a planting panel board 3 made of foamed plastic such as polystyrene foam, and a waterproof sheet (not shown) laid on the cultivation bed 2. No hydrophilic sheet is used.

The bottom surface of the cultivation bed 2 is provided with a ridge 2t extending in the longitudinal direction of the cultivation bed 2. In this embodiment, multiple parallel ridges 2t are provided, but a single ridge may also be provided. A plant (seedling root pot 9) is placed on the ridge 2t.

A seedling root ball is a net-like growth of the roots of plants grown in individual pots or cell trays, enveloping the medium. When the roots have grown sufficiently and are tightly wound, the seedlings can be transplanted even after being removed from the pots or cell trays, as the root ball protects the medium and prevents it from crumbling. The medium may be granular.

The cultivation bed 2 is a long box-like shape that extends in one direction with an open top, and has an upwardly facing U-shaped cross section with a pair of long side walls 2a, 2a and a bottom plate portion 2b.

The intersection edge between the upper end faces of the long side walls 2a, 2a and the inner surface forms a notched step 2d, with which the side edge of the planting panel plate 3 engages.

The cultivation bed 2 of this embodiment is installed on a cultivation bench (not shown) with a gradient so that the upper surface of the bottom plate portion 2b (the surface of the bottom surface of the cultivation bed 2 other than the convex strips 2t) has a gradient (flow gradient) in the longitudinal direction, and the upper surface of the convex strips 2t is installed approximately horizontally. Therefore, the convex strip height _h1 on the downstream side of the flow gradient shown in Figure 4 is larger than the convex strip height _h2 on the upstream side. The upper surface of the convex strips 2t is preferably horizontal, but may have a very slight gradient (within 1/66).

The width w ₁ (FIG. 4) of the ridges 2t is preferably 15 to 55 mm, particularly preferably 25 to 45 mm, and the interval w ₂ between the ridges 2t is preferably 60 to 90 mm, particularly preferably 65 to 85 mm.

To allow water to flow over the bottom plate portion 2b of the cultivation bed 2 other than the ridges 2t, it is preferable that the gradient of the cultivation bench is 1/70 to 1/150, and more preferably 1/75 to 1/120.

The weirs 2f are provided at intervals in the longitudinal direction of the cultivation bed 2. The weirs 2f extend in the width direction of the cultivation bed 2. The interval between the weirs 2f is preferably 0.8 to 1.2 m, and more preferably 0.9 to 1.1 m.

The height of the weir 2f is set so that the convex strip 2t is submerged in the liquid that accumulates upstream of the weir 2f in terms of the flow gradient. Preferably, the distance between the top surface of the convex strip 2t and the liquid surface (the water depth at the top surface of the convex strip 2t) is 1 to 5 mm, particularly 1 to 3 mm. This configuration makes it suitable for use in growing seedlings after planting.

The longitudinal length of the cultivation bed 2 and the planting panel board 3 is not limited, but is preferably 5 m or more, and more preferably 10 m or more. The length is preferably 50 m or less, and more preferably 30 m or less.

The planting panel plate 3 has a number of planting holes 3a spaced apart in the longitudinal direction above each ridge 2t. The longitudinal spacing between the planting holes 3a can be designed appropriately depending on the type of plant being cultivated, but is not limited to a specific value. For example, a spacing of 60 to 100 mm is preferable, and in particular, a spacing of 75 to 90 mm is preferable. In the illustrated embodiment, five ridges 2t are provided, resulting in five rows of planting holes 3a, but the number of ridges 2t and the number of planting holes 3a are not limited to this.

The shape of the planting hole 3a may be cylindrical as shown in the figure, or may be prismatic or of other shapes.

The waterproof sheet (not shown) is provided to cover the upper end and inner surfaces of the long side walls 2a, 2a of the cultivation bed 2, and the upper surface of the bottom plate portion 2b. The waterproof sheet is laid continuously from the upstream end of the flow gradient of the cultivation bed 2 to the downstream end. The waterproof sheet is laid so as to climb over the weir 2f.

The cultivation beds 2 may be connected in series by butting them together. In this case, the waterproof sheet is laid continuously across each cultivation bed 2. This prevents water leakage from the butting surfaces between the cultivation beds 2.

A drainage channel member 5 (Figs. 2 and 3) is installed at the downstream end of the most downstream cultivation bed 2. The nutrient solution that overflows the weir 2f at the most downstream end flows into the drainage channel member 5.

In one embodiment of the present invention, the seedling root ball 9 is placed on the ridge 2t through the planting hole 3a of the planting panel plate 3 covering each cultivation bed 2, and the lower part of the seedling root ball 9 is immersed in the nutrient solution stored in the cultivation bed 2 to cultivate the plant P in a nutrient solution hydroponic system. Flooded solution hydroponic system is a method of immersing the roots in nutrient solution. It is preferable to immerse the lower part of the seedling root ball 9 in the nutrient solution by about 1 to 10 mm, and particularly about 1 to 5 mm. In this way, in nutrient solution hydroponic system, if a slope is provided on the cultivation bench and the bottom plate part 2b of the cultivation bed has a slope, when the cultivation bed is washed after the end of cultivation, the dirty water after washing is drained along the slope, making washing easier.

By setting the cultivation bed 2 on the cultivation bench so that the top surface of the ridges 2t is horizontal, the depth of water submersion in each seedling root ball 9 becomes uniform. At this time, by setting the height ratio of the submerged portion of the seedling root ball 9 to the portion that is maintained in the moist space, which is the space between the planting panel plate 3 and the water surface, to 1:10 to 1:5, in addition to the area where nutrient solution is supplied to the seedling root ball 9, an area where moist roots are generated from the seedling root ball 9 is secured, and the growth of moist roots becomes stable. In addition, the cultivation bed bottom plate portion 2b between the ridges 2t is set to have a flow gradient, so that the nutrient solution flows slowly over the cultivation bed 2 according to the flow gradient without stagnating.

This makes it difficult for the culture medium in the seedling root ball 9 to be washed away by the nutrient solution, and stable cultivation can be achieved. In particular, in liquid-filled hydroponic cultivation, the bottom surface of the cultivation bed is not usually set to have a slope, so that the culture medium in the seedling root ball does not become easily washed away due to the slope, as described above, and there is no need to provide such a convex strip 2t. In addition, by setting the amount of nutrient solution held between adjacent weirs 2f, 2f to 10 to 15 L and setting the amount of nutrient solution supplied to 2 to 5 L/min, the entire amount of nutrient solution is exchanged in 3 to 5 minutes, and contamination of the nutrient solution (such as proliferation of microorganisms) can be suppressed. The average flow rate of the nutrient solution between adjacent weirs 2f, 2f is preferably 2 to 12 L/min, and particularly 5 to 10 L/min. By being within the above range, the flow rate is different between the convex strips 2t on the top of the convex strips 2t and the convex strips 2t on the bottom surface of the cultivation bed, making it even more difficult for the culture medium in the seedling root ball 9 to be washed away.

By arranging a nutrient solution circulation mechanism having a tank, piping, pump, etc. in the above-mentioned cultivation bed, a nutrient solution cultivation system can be created. Figure 5 is a plan view showing an example of a nutrient solution cultivation system.

In FIG. 5, a number of cultivation beds 2 are connected in series inside a greenhouse to form a cultivation bed row 10, and these cultivation bed rows 10 are arranged in a number of rows (four rows in the figure) to form a cultivation bed group 20. In one cultivation bed row 10, a number of cultivation beds 2 are arranged in series, and a waterproof sheet is laid across each cultivation bed 2. This prevents water leakage from the joints between the cultivation beds 2. The number of cultivation beds 2 that make up one cultivation bed row 10 is about 5 to 100, but is not limited to this.

Each row of cultivation beds 10 is installed on a cultivation bench (not shown) so that the bottom plate portion 2b of the cultivation bed 2 other than the convex strips 2t has a flow gradient from one end to the other end in the longitudinal direction.

One tank 33 is installed in association with each group of cultivation beds 20. This nutrient solution cultivation system has a tank 33 that stores the circulating nutrient solution, and the nutrient solution in the tank 33 is supplied to each row of cultivation beds 10 via a pump 34, piping 35, and valve 36.

In order to supply the tank 33 with an amount of water equivalent to the amount of nutrient solution absorbed by the plants, a raw water tank (not shown), a supply control valve 25a, and piping 25 are provided, and the amount of water supplied to the tank 33 is controlled by a ball tap 31, which is a float valve, so that the amount of liquid stored in the tank 33 is always constant.

An outflow channel 37 is provided so that the nutrient solution returns to the tank 33 from the drainage channel member 5 at the end of each row of cultivation beds 10.

In this nutrient solution cultivation system, a tank (not shown) for storing concentrated liquid fertilizer, a supply control valve 24a for supplying the liquid fertilizer, and piping 24 are provided to supply liquid fertilizer to tank 33. The total fertilizer concentration of the circulating nutrient solution is represented by electrical conductivity (EC). Tank 33 is equipped with a sensor unit that measures the EC value, and concentrated liquid fertilizer is replenished when the EC of the nutrient solution in tank 33 falls below a certain value. Note that the system for supplying liquid fertilizer to the nutrient solution cultivation system preferably replenishes liquid fertilizer from two tanks that store two or more types of concentrated liquid fertilizer.

This nutrient solution cultivation system does not use a hydrophilic sheet, so there is no need to install, remove, clean, disinfect, or otherwise dispose of the hydrophilic sheet, and plant P can be cultivated efficiently.

REFERENCE SIGNS LIST 1 Nutrient solution cultivation system 2 Cultivation bed 2b Bottom plate 2f Weir 2t Convex strip 3 Planting panel 3a Planting hole 9 Seedling root ball 10 Cultivation bed row 20 Cultivation bed tank group 31 Ball tap 33 Tank 34 Pump

Claims (7)

A hydroponic cultivation system having a cultivation bed and a cultivation bench,
The cultivation bench has a slope on the upper surface,
The cultivation bed is installed on the upper surface of the cultivation bench, so that the bottom surface of the cultivation bed has a slope;
A convex stripe extending in a gradient direction is provided on a bottom surface of the cultivation bed, and an upper surface of the convex stripe is substantially horizontal;
A hydroponic cultivation system characterized in that a dam for storing nutrient solution is provided in the cultivation bed so that the upper surfaces of the protrusions are submerged in the nutrient solution. The nutrient solution cultivation system of claim 1, wherein the difference between the level of the nutrient solution stored by the weir and the level of the upper surface of the ridge is 1 to 10 mm. The hydroponic cultivation system of claim 1 or 2, in which the ridges are provided in multiple rows. A nutrient solution cultivation system according to any one of claims 1 to 3, in which a waterproof sheet is provided to cover the bottom surface of the cultivation bed, but no hydrophilic sheet is provided. A hydroponic cultivation system according to any one of claims 1 to 4, comprising a planting panel plate having a plurality of planting holes arranged on the cultivation bed, each planting hole being positioned above the ridge. A nutrient solution cultivation method using the nutrient solution cultivation system according to any one of claims 1 to 5. 6. A nutrient solution cultivation method using the nutrient solution cultivation system of claim 5, comprising the steps of: placing seedling root balls on the convex ridges through the planting holes in the planting panel plate; and immersing the lower part of the seedling root ball in the nutrient solution stored in the cultivation bed to cultivate the plants.

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