Hydroponic cultivation device and hydroponic cultivation method

Abstract

To provide a hydroponic cultivation device and a hydroponic cultivation method capable of stably supplying culture solution and oxygen to roots of crops.SOLUTION: A hydroponic cultivation device 1 includes: a tank 2 having a flow path 21; a first liquid absorption mat 6 arranged on a bottom surface 21a of the flow path 21; and a drainage promotion member 7 arranged between the bottom surface 21a and the first liquid absorption mat 6 and having a plurality of ridges 71 and grooves 72 located between the plurality of ridges 71. In the hydroponic cultivation device 1, the tank 2 is installed so that the bottom surface 21a is inclined, and a crop α is arranged on the first liquid absorption mat 6. A supply step of supplying a culture solution β to the flow path 21 to cause the first liquid absorption mat 6 to absorb the culture solution β, and a stop step of stopping the supply of the culture solution β to the flow path 21 are repeated.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a hydroponic cultivation apparatus and a hydroponic cultivation method for hydroponic cultivation of crops such as strawberries. [Background technology]

[0002] Conventionally, the Nutrient Film Technique (NFT) method has been known as one of the hydroponic cultivation methods. In the NFT method, the roots of a crop are placed on a gently sloping flow path, and a thin layer of nutrient solution is poured on the slope to supply nutrient solution and oxygen to the roots of the crop (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 02-023456 Summary of the Invention [Problem to be solved by the invention]

[0004] Among hydroponic cultivation methods, the NFT method is relatively good at supplying oxygen to the roots. However, in the NFT method, root mats are formed by densely packing roots on the surface of the nutrient solution flow path, and when the turgor pressure of the root mat decreases and the nutrient solution accumulates in the root mat, the root mat becomes poorly aerated and oxygen is insufficient. Moreover, in the NFT method, if the supply of nutrient solution stops due to a breakdown in the power supply equipment, the roots cannot be supplied with nutrient solution and the crops die.

[0005] By the way, when strawberries are cultivated by the NFT method, the terminal fruit cluster can be harvested without any problems, but the tree vigor decreases afterwards, and the yield often decreases. This is presumed to be due to the following reasons. That is, it is known that the roots of strawberries function as a storage site for photosynthetic products, and when the terminal fruit cluster is about to be harvested, the photosynthetic products stored in the roots are consumed, causing the roots to wear out, and some of the roots die or rot. This root wear causes the turgor pressure of the root mat to decrease, leading to poor aeration and oxygen deficiency, which further weakens the roots, creating a vicious cycle that is presumed to cause poor growth in the latter half of the harvest season. For this reason, if the roots can be stably supplied with nutrient solution and oxygen, the strawberry yield can be stabilized.

[0006] An object of the present invention is to provide a hydroponic cultivation apparatus and a hydroponic cultivation method capable of stably supplying a culture solution and oxygen to the roots of crops. [Means for solving the problem]

[0007] [1] A hydroponic cultivation device according to the present invention comprises a tank having a flow path, a first liquid-absorbing mat arranged on a bottom surface of the flow path, and a drainage promotion member arranged between the bottom surface and the first liquid-absorbing mat, the drainage promotion member having a plurality of ridges and grooves located between the plurality of ridges.

[0008] In this hydroponic cultivation device, the first liquid absorption mat is placed on the bottom surface of the flow path of the tank, so that the tank is installed so that the bottom surface is inclined, crops are placed on the first liquid absorption mat, and the culture solution is supplied to the flow path to be absorbed by the first liquid absorption mat, so that the culture solution can be supplied from the first liquid absorption mat to the roots of the crop. Even if the supply of the culture solution is stopped, the first liquid absorption mat can maintain a state in which the culture solution is held, so that the culture solution can be continued to be supplied from the first liquid absorption mat to the roots of the crop. Moreover, in this hydroponic cultivation device 1, a drainage promotion member having a plurality of ridges and grooves located between the plurality of ridges is placed between the bottom surface and the first liquid absorption mat, so that when the supply of the culture solution to the flow path is stopped, the culture solution is quickly discharged through the grooves of the drainage promotion member below the first liquid absorption mat. As a result, a space is formed between the first liquid absorption mat and the bottom surface in which the roots of the crop come into contact with the air, so that oxygen in the air can be supplied to the roots of the crop below the first liquid absorption mat. Therefore, by repeatedly supplying and stopping the culture solution to the flow path, the culture solution can be continuously supplied to the roots of the crop from the first liquid absorption mat while intermittently supplying oxygen to the roots of the crop below the first liquid absorption mat, thereby enabling a stable supply of culture solution and oxygen to the roots of the crop.

[0009] [2] The hydroponic cultivation device according to [1] may further include a panel disposed above the bottom surface and having a planting hole. In this hydroponic cultivation device, the panel having the planting hole is disposed above the bottom surface, so that crops can be planted at predetermined positions on the first liquid absorbing mat.

[0010] [3] In the hydroponic cultivation device described in [2], the planting hole may be located above the groove. In this hydroponic cultivation device, since the planting hole is located above the groove, air can be passed through the lower surface of the first liquid absorbing mat at a position facing the crop. This can increase the amount of oxygen supplied to the roots of the crop via the first liquid absorbing mat.

[0011] [4] The hydroponic cultivation device according to any one of [1] to [3] may further include a support device for supporting the tank so that the bottom surface is inclined, a supply device for supplying the culture solution to the flow path, and a recovery device for recovering the culture solution from the flow path. Since the hydroponic cultivation device includes the support device, the tank can be easily installed so that the bottom surface is inclined. Furthermore, since the supply device and the recovery device are included, the culture solution can be easily supplied to and recovered from the flow path.

[0012] [5] In the hydroponic cultivation device according to any one of [1] to [4], the top of each of the plurality of peaks may have a tapered shape. In this hydroponic cultivation device, since the top of each of the plurality of peaks has a tapered shape, the contact area between the drainage promotion member and the first absorbent mat can be reduced. This improves the breathability in the vicinity of the lower surface of the first absorbent mat, and therefore the amount of oxygen supplied to the roots of the crops via the first absorbent mat can be increased.

[0013] [6] In the hydroponic cultivation device according to any one of [1] to [5], the groove may have a first groove extending in the extension direction of the flow path and reaching both ends of the drainage promotion member in the extension direction. In this hydroponic cultivation device, since the groove has the first groove extending in the extension direction of the flow path and reaching both ends of the drainage promotion member in the extension direction, the culture solution can flow on the drainage promotion member along the slope of the bottom surface. This can improve the drainage property of the drainage promotion member.

[0014] [7] In the hydroponic cultivation device according to any one of [1] to [6], the groove portion may have a second groove portion extending in the width direction of the flow path and reaching both ends of the drainage promotion member in the width direction. In this hydroponic cultivation device, since the groove portion has the second groove portion extending in the width direction of the flow path and reaching both ends of the drainage promotion member in the width direction, the culture solution can flow in the width direction on the drainage promotion member. This can improve the drainage property of the drainage promotion member.

[0015] [8] In the hydroponic cultivation device according to any one of [1] to [7], the drainage promotion member may have a through hole formed in the groove. In this hydroponic cultivation device, since the drainage promotion member has the through hole, the culture solution flowing through the groove can be discharged to the outside of the groove at an earlier stage. This can improve the drainage property of the drainage promotion member.

[0016] [9] In the hydroponic cultivation device according to any one of [1] to [8], the depth of the groove may be 0.3 cm or more and 5 cm or less. In this hydroponic cultivation device, since the depth of the groove is 0.3 cm or more and 5 cm or less, it is possible to improve the drainage performance of the drainage promotion member while preventing the drainage promotion member from becoming large.

[0017]

[10] In the hydroponic cultivation device according to any one of [1] to [9], the thickness of the drainage promotion member may be more than 0.3 cm and not more than 5.2 cm. In this hydroponic cultivation device, since the thickness of the drainage promotion member is more than 0.3 cm and not more than 5.2 cm, it is possible to improve the drainage performance of the drainage promotion member while preventing the drainage promotion member from becoming large.

[0018]

[11] In the hydroponic cultivation device according to any one of [1] to

[10] , the first liquid absorption mat and the liquid drainage promotion member may be located to one side in the width direction of the flow path. In this hydroponic cultivation device, since the first liquid absorption mat and the liquid drainage promotion member are located to one side in the width direction of the flow path, the width of the flow path between the first liquid absorption mat and the liquid drainage promotion member and the side surface of the flow path is widened. This reduces the flow resistance of the culture solution flowing on the bottom surface, and therefore it is possible to prevent the culture solution from accumulating in the flow path.

[0019]

[12] The hydroponic cultivation device according to any one of [1] to

[11] may further include a second liquid-absorbing mat disposed between the bottom surface and the drainage promotion member. In this hydroponic cultivation device, the second liquid-absorbing mat is disposed between the bottom surface and the drainage promotion member, and the second liquid-absorbing mat absorbs the culture solution, thereby promoting the movement of the culture solution flowing on the bottom surface. This makes it possible to prevent the culture solution from accumulating in the flow path.

[0020]

[13] The hydroponic cultivation device according to any one of [1] to

[12] may further include a root-proof water-permeable sheet that divides the space in the flow path into an area including the bottom surface and the drainage promotion member and an area not including the bottom surface and the drainage promotion member. Since the space between the bottom surface and the drainage promotion member has poor ventilation, when a root mat is formed, it is likely to become oxygen-deficient. However, in this hydroponic cultivation device, the root-proof water-permeable sheet divides the space in the flow path into an area including the bottom surface and the drainage promotion member and an area not including the bottom surface and the drainage promotion member, so that it is possible to prevent the roots of the crop from growing between the bottom surface and the drainage promotion member. This makes it possible to prevent a root mat from being formed between the bottom surface and the drainage promotion member, which causes oxygen deficiency.

[0021]

[14] A hydroponic cultivation method using the hydroponic cultivation device described in any one of [1] to

[13] , comprising repeatedly setting a tank with an inclined bottom, placing crops on a first liquid absorption mat, and supplying culture solution to a flow path to allow the first liquid absorption mat to absorb the culture solution, and stopping a supply of culture solution to the flow path.

[0022] In this hydroponic cultivation method, by repeating the supply process and the stop process, it is possible to continue the supply of culture solution from the first liquid absorption mat to the roots of the crop while intermittently supplying oxygen to the roots of the crop below the first liquid absorption mat, thereby enabling a stable supply of culture solution and oxygen to the roots of the crop. Effect of the Invention

[0023] According to the present invention, a nutrient solution and oxygen can be stably supplied to the roots of crops. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram of a hydroponic cultivation device according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a plan view of a hydroponic cultivation device according to a first embodiment. [Diagram 3] 3 is a cross-sectional view taken along line III-III shown in FIG. 2. [Figure 4]FIG. 4 is a plan view of the hydroponic cultivation device with the panel and the first liquid absorbing mat removed. [Diagram 5] 5 is a cross-sectional view taken along line VV shown in FIG. [Figure 6] 6 is a cross-sectional view taken along line VI-VI shown in FIG. [Figure 7] 7(a), 7(b) and 7(c) are cross-sectional views showing examples of the top of the drainage member. [Figure 8] FIG. 11 is a cross-sectional view of the hydroponic cultivation apparatus in a supplying step. [Figure 9] FIG. 11 is a cross-sectional view of the hydroponic cultivation device in a stopping process. [Figure 10] FIG. 4 is a cross-sectional view of a hydroponic cultivation device according to a second embodiment. [Figure 11] FIG. 11 is a cross-sectional view of a hydroponic cultivation device according to a third embodiment. [Figure 12] FIG. 13 is a cross-sectional view of a hydroponic cultivation device according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, embodiments of a hydroponic cultivation apparatus and a hydroponic cultivation method according to the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted.

[0026] [First embodiment] Fig. 1 is a schematic diagram of a hydroponic cultivation device according to this embodiment. Fig. 2 is a plan view of the hydroponic cultivation device according to the first embodiment. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. As shown in Figs. 1 to 3, the hydroponic cultivation device 1 according to this embodiment includes a tank 2, a support device 3, a supply device 4, a recovery device 5, a first liquid-absorbent mat 6, a drainage promotion member 7, a second liquid-absorbent mat 8, and a panel 9.

[0027] The tank 2 has a flow path 21 for hydroponic cultivation of the crop α. The flow path 21 is a flow path for a culture solution β (see FIG. 8), also called a channel or the like. The flow path 21 extends linearly. The direction in which the flow path 21 extends is called an extension direction D1. The crop α is not particularly limited, and may be, for example, strawberries, tomatoes, green peppers, paprika, melons, cucumbers, roses, chrysanthemums, etc. The culture solution β is a liquid containing water and nutrients necessary for the cultivation of the crop α.

[0028] The tank 2 is composed of a bottom wall 22 forming a bottom surface 21a of the flow path 21, a side wall 23 forming a side surface 21b on one side of the flow path 21, and a side wall 24 forming a side surface 21c on the other side of the flow path 21. The bottom wall 22 has a cross section extending in the width direction D2 of the flow path 21, for example, and extends in the extension direction D1. The width direction D2 is a direction perpendicular to the extension direction D1. The side wall 23 and the side wall 24 are erected from an end of the bottom wall 22 in the width direction D2 so as to face each other in the width direction D2, for example. Each of the side wall 23 and the side wall 24 has a cross section extending in the height direction D3 of the flow path 21, for example, and extends in the extension direction D1. The height direction D3 is a direction perpendicular to the extension direction D1 and the width direction D2. The bottom surface 21a of the flow path 21 is formed in a flat shape. In addition, one end of the bottom surface 21a in the extension direction D1 is referred to as the first end 21d, and the other end of the bottom surface 21a in the extension direction D1 is referred to as the second end 21e. In FIG. 1, the right end of the bottom surface 21a is the first end 21d, and the left end of the bottom surface 21a is the second end 21e.

[0029] The support device 3 supports the tank 2 so that the bottom surface 21a of the flow path 21 is inclined in the extension direction D1. Specifically, the support device 3 supports the tank 2 so that the bottom surface 21a becomes lower from the first end 21d side toward the second end 21e side. The gradient of the bottom surface 21a is, for example, about 1 / 75 to 1 / 100. The support device 3 is, for example, composed of a plurality of supports having different heights. In FIG. 1, the support device 3 is composed of two supports having different heights, the higher support supports the vicinity of the first end 21d of the tank 2, and the lower support supports the vicinity of the second end 21e of the tank 2. The support device 3 may support the tank 2 so that the gradient of the bottom surface 21a can be changed.

[0030] The supply device 4 supplies the culture solution β onto the bottom surface 21a of the flow path 21. The supply device 4 has a supply pipe 4b having a discharge port 4a formed therein through which the culture solution β is discharged, and a pump (not shown) that sends the culture solution β to the supply pipe 4b. The discharge port 4a is disposed at a position where the culture solution β can be supplied onto the first end 21d of the flow path 21 or onto the bottom surface 21a in the vicinity of the first end 21d. The culture solution β supplied to the flow path 21 flows on the bottom surface 21a from the first end 21d side to the second end 21e side due to the inclination of the bottom surface 21a.

[0031] The recovery device 5 recovers the culture solution β from the flow path 21. The recovery device 5 has a recovery pipe 5b formed with a recovery port 5a for receiving the culture solution β, and a storage tank (not shown) for storing the culture solution β recovered by the recovery pipe 5b. The recovery device 5 can recover the culture solution β that has dropped from the second end 21e, for example, by arranging the recovery port 5a below the bottom surface 21a near the second end 21e. In addition, the recovery device 5 can recover the culture solution β from above the bottom surface 21a, for example, by having the recovery port 5a be an opening formed in the bottom surface 21a of the flow path 21. Note that, between the recovery device 5 and the supply device 4, a circulation flow path (not shown) for supplying the culture solution β recovered by the recovery device 5 to the supply device 4, and a filter (not shown) for removing impurities from the culture solution β recovered by the recovery device 5 may be provided.

[0032] 2 and 3, the first liquid-absorbent mat 6 is a mat placed on the bottom surface 21a of the flow path 21. The first liquid-absorbent mat 6 has a liquid-absorbency that allows it to absorb and hold the culture solution β by capillary action (capillary absorption) or the like when it comes into contact with the culture solution β.

[0033] Fig. 4 is a plan view of the hydroponic cultivation device with the panel and the first liquid absorbing mat removed. As shown in Figs. 2 to 4, the drainage promotion member 7 is a member disposed between the bottom surface 21a and the first liquid absorbing mat 6. The drainage promotion member 7 is a member for promoting the drainage of the culture solution β below the first liquid absorbing mat 6. The drainage promotion member 7 has a plurality of ridges 71, grooves 72 located between the plurality of ridges 71, and through holes 73 formed in the grooves 72.

[0034] The multiple ridges 71 are portions that contact the first absorbent mat 6 and support the first absorbent mat 6. The multiple ridges 71 are arranged in the extension direction D1 and the width direction D2. That is, the multiple ridges 71 are arranged in the extension direction D1, and the multiple ridges 71 are arranged in the width direction D2.

[0035] FIG. 5 is a cross-sectional view taken along line VV in FIG. 4. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4. As shown in FIGS. 4 to 6, the groove portion 72 has a plurality of first groove portions 74 extending in the extension direction D1 to both ends of the drainage promotion member 7 in the extension direction D1, and a plurality of second groove portions 75 extending in the width direction D2 to both ends of the drainage promotion member 7 in the width direction D2. That is, each of the plurality of first groove portions 74 extends in the extension direction D1 from the tip of the other side of the drainage promotion member 7 in the extension direction D1 to the tip of the other side of the drainage promotion member 7 in the extension direction D1. Also, each of the plurality of second groove portions 75 extends in the width direction D2 from the tip of one side of the drainage promotion member 7 in the width direction D2 to the tip of the other side of the drainage promotion member 7 in the width direction D2. The plurality of first groove portions 74 and the plurality of second groove portions 75 are perpendicular to each other.

[0036] The depth D of the groove 72 is, for example, 0.3 cm to 5 cm, preferably 0.4 cm to 3.5 cm, and more preferably 0.6 cm to 2 cm. The depth D of the groove 72 is the dimension in the height direction D3 and is also the height of each of the multiple ridges 71.

[0037] 7(a), 7(b) and 7(c) are cross-sectional views showing examples of the top of the drainage member. The top 71a of each of the multiple peaks 71 may be formed in a dome shape as shown in FIG. 7(a), may be formed in a pyramidal shape such as a cone or a square pyramid as shown in FIG. 7(b), or may be formed in a columnar shape such as a cylinder or a square prism as shown in FIG. 7(c). From the viewpoint of reducing the contact area between the first liquid-absorbent mat 6 and the multiple peaks 71, the top 71a preferably has a tapered shape as shown in FIG. 7(a) or FIG. 7(b). Having a tapered shape means that the top 71a is formed to be thinner toward the tip (apex). From the same viewpoint, the top 71a preferably does not have a plane parallel to the extension direction D1 and the width direction D2 as shown in FIG. 7(a) or FIG. 7(b). In the present embodiment, the top 71a is described as having a tapered shape as an example.

[0038] Each of the plurality of ridges 71 may be solid, but from the viewpoint of weight reduction, it is preferable that each of the ridges 71 is hollow. The drainage promotion member 7 in which each of the plurality of ridges 71 is hollow can be manufactured by, for example, sheet molding using a thermoplastic resin.

[0039] 5 and 6, the thickness T of the drainage promotion member 7 is, for example, more than 0.3 cm and not more than 5.2 cm, preferably more than 0.4 cm and not more than 3.7 cm, and more preferably more than 0.6 cm and not more than 2.2 cm. More than 0.3 cm means greater than 0.3 cm. The thickness T of the drainage promotion member 7 is the dimension in the height direction D3, and is also the dimension obtained by adding the height of each of the multiple ridges 71 to the thickness of the drainage promotion member 7.

[0040] 2 to 4, the second absorbent mat 8 is a mat disposed between the bottom surface 21a of the flow path 21 and the drainage promotion member 7. The second absorbent mat 8 has, for example, the same absorbency as that of the first absorbent mat 6.

[0041] The first absorbent mat 6, the drainage promotion member 7, and the second absorbent mat 8 are formed smaller in the width direction D2 than the bottom surface 21a, and are arranged toward one side of the flow path 21 in the width direction D2. Specifically, the first absorbent mat 6, the drainage promotion member 7, and the second absorbent mat 8 are arranged toward the side surface 21b on the bottom surface 21a, and the flow path width between the first absorbent mat 6, the drainage promotion member 7, and the second absorbent mat 8 and the side surface 21c is wide. Since the first absorbent mat 6, the drainage promotion member 7, and the second absorbent mat 8 become flow resistance of the culture solution β flowing on the bottom surface 21a, most of the culture solution β flows through the area on the bottom surface 21a where the first absorbent mat 6, the drainage promotion member 7, and the second absorbent mat 8 are not arranged, and is absorbed by the first absorbent mat 6 and the second absorbent mat 8 from the area.

[0042] The first and second absorbent mats 6 and 8 are formed wider in the width direction D2 than the drainage promotion member 7, and protrude on both sides in the width direction D2 from the drainage promotion member 7. An end of the first absorbent mat 6 on the side surface 21c hangs down from the drainage promotion member 7, and a tip of the first absorbent mat 6 on the side surface 21c is located lower than the upper end of the drainage promotion member 7 (the upper ends of the multiple ridges 71).

[0043] The panel 9 is disposed above the bottom surface 21a. The panel 9 is disposed above the bottom surface 21a, for example, by being placed so as to span the upper ends of the side walls 23 and 24. The panel 9 is formed with a plurality of planting holes 91 for planting the crop α. The panel 9 is capable of, for example, hanging the crop α inserted into the planting holes 91, thereby causing the crop α to collide with a predetermined position. For example, the root ball of the crop α from which the pot has been removed is inserted into the planting holes 91. The root ball of the crop α may be one from which the soil has been removed, or one from which the soil has not been removed. When the panel 9 is disposed above the bottom surface 21a, each of the plurality of planting holes 91 is located above the groove portion 72 of the drainage promotion member 7. Therefore, the crop α planted through the planting holes 91 is located above the groove portion 72 of the drainage promotion member 7.

[0044] Next, a hydroponic cultivation method according to this embodiment will be described. The hydroponic cultivation method according to this embodiment is a method for hydroponic cultivation of a crop α using the hydroponic cultivation apparatus 1 described above.

[0045] In the hydroponic cultivation method according to the present embodiment, first, as shown in Figs. 1 to 3, the hydroponic cultivation device 1 is installed so that the bottom surface 21a of the tank 2 is inclined. When installing the hydroponic cultivation device 1, the tank 2 is installed by the support device 3 so that the bottom surface 21a becomes lower at a gradient of about 1 / 75 to 1 / 100 from the first end 21d side toward the second end 21e side. In addition, the second liquid absorption mat 8, the drainage promotion member 7, and the first liquid absorption mat 6 are layered in this order on the bottom surface 21a of the tank 2 near the side surface 21b. In addition, the panel 9 is installed in the tank 2 so that the planting hole 91 of the panel 9 is positioned above the groove portion 72 of the drainage promotion member 7.

[0046] Next, the root ball of the crop α is inserted into the planting hole 91 of the panel 9 to place the crop α on the first liquid absorption mat 6, and the roots of the crop α are brought into contact with the first liquid absorption mat 6. Thereafter, the supplying process and the discharging process described below are repeated.

[0047] FIG. 8 is a cross-sectional view of the hydroponic cultivation device in the supplying step. As shown in FIG. 8, in the supplying step, the culture solution β is supplied to the flow path 21 to absorb the culture solution β into the first liquid absorption mat 6. To explain in detail, in the supplying step, the culture solution β is supplied onto the bottom surface 21a by the supplying device 4. Then, the culture solution β supplied to the flow path 21 flows from the first end 21d side to the second end 21e side on the bottom surface 21a due to the inclination of the bottom surface 21a, and is collected by the collecting device 5. At this time, the culture solution β is supplied onto the bottom surface 21a to such an extent that the liquid level of the culture solution β is at the position of the first liquid absorption mat 6, and the culture solution β flowing on the bottom surface 21a is absorbed into the first liquid absorption mat 6 and the second liquid absorption mat 8. As a result, the culture solution β is supplied from the first liquid absorption mat 6 to the roots of the crop α, and oxygen in the air above the first liquid absorption mat 6 is supplied to the roots of the crop α. In addition, the roots of the crop α grow to below the first liquid absorbing mat 6, for example by penetrating through the first liquid absorbing mat 6, and the culture solution β flowing on the bottom surface 21a is supplied to the roots of the crop α below the first liquid absorbing mat 6.

[0048] FIG. 9 is a cross-sectional view of the hydroponic cultivation device in the stop step. As shown in FIG. 9, in the stop step, the supply of the culture solution β to the flow path 21 is stopped. To explain in detail, in the stop step, the supply of the culture solution β to the bottom surface 21a of the flow path 21 by the supply device 4 is stopped. Then, the liquid level of the culture solution β flowing on the bottom surface 21a drops, and the excess culture solution β in the first liquid-absorbent mat 6 and the excess culture solution β below the first liquid-absorbent mat 6 are discharged to the outside of the drainage promotion member 7 through the groove portion 72. The excess culture solution β in the first liquid-absorbent mat 6 is, for example, the culture solution β absorbed in excess of the retention limit of the first liquid-absorbent mat 6, and is the culture solution β discharged from the first liquid-absorbent mat 6 by gravity. The excess culture solution β below the first liquid-absorbent mat 6 is the culture solution β between the drainage promotion member 7 and the first liquid-absorbent mat 6. As a result, a space is formed between the first liquid absorption mat 6 and the second liquid absorption mat 8 where the roots of the crop α are exposed to the air, and oxygen in the air is supplied to the roots of the crop α below the first liquid absorption mat 6. On the other hand, even if the supply of the culture solution β is stopped, the culture solution β continues to be supplied from the first liquid absorption mat 6 and the second liquid absorption mat 8 to the roots of the crop α because the culture solution β is held in the first liquid absorption mat 6 and the second liquid absorption mat 8.

[0049] Here, if the culture solution β is continuously supplied to the flow path 21, the roots of the crop α that have grown below the first liquid absorbing mat 6 will remain submerged in the culture solution β and will not be supplied with oxygen. In particular, a root mat of the roots of the crop α is likely to form below the first liquid absorbing mat 6, and this root mat will also remain submerged in the culture solution β and will not be supplied with oxygen. Therefore, after the supplying process is performed for a predetermined period of time, a stopping process is performed to prevent the roots of the crop α from becoming oxygen-deficient. In addition, after the stopping process is performed for a predetermined period of time, a supplying process is performed again to prevent the roots of the crop α from becoming nutrient-deficient. The supplying process and the stopping process are repeated to perform hydroponic cultivation of the crop α.

[0050] As described above, in the hydroponic cultivation device 1 according to this embodiment, the first liquid absorbing mat 6 is disposed on the bottom surface 21a of the flow path 21 of the tank 2, so that the tank 2 is installed so that the bottom surface 21a is inclined, the crop α is disposed on the first liquid absorbing mat 6, and the culture solution β is supplied to the flow path 21 to be absorbed by the first liquid absorbing mat 6, so that the culture solution β can be supplied from the first liquid absorbing mat 6 to the roots of the crop α. Even if the supply of the culture solution β is stopped, the first liquid absorbing mat 6 can maintain the state in which it holds the culture solution β, so that the culture solution β can be continuously supplied from the first liquid absorbing mat 6 to the roots of the crop α. Moreover, in this hydroponic cultivation device 1, the drainage promotion member 7 having a plurality of ridges 71 and grooves 72 located between the plurality of ridges 71 is disposed between the bottom surface 21a and the first liquid absorbing mat 6, so that when the supply of the culture solution β to the flow path 21 is stopped, the culture solution β is quickly discharged below the first liquid absorbing mat 6 through the grooves 72 of the drainage promotion member 7. As a result, a space is formed between the first liquid absorbing mat 6 and the bottom surface 21a where the roots of the crop α are exposed to air, and oxygen in the air can be supplied to the roots of the crop α below the first liquid absorbing mat 6. Therefore, by repeatedly starting and stopping the supply of the culture solution β to the flow path 21, the supply of the culture solution from the first liquid absorbing mat 6 to the roots of the crop α can be continued while intermittently supplying oxygen to the roots of the crop α below the first liquid absorbing mat, and therefore the culture solution β and oxygen can be stably supplied to the roots of the crop α.

[0051] In addition, in this hydroponic cultivation device 1, the second absorbent mat 8 is disposed between the bottom surface 21a and the drainage promotion member 7, and therefore the culture solution β is absorbed into the second absorbent mat 8, thereby promoting the movement of the culture solution β flowing on the bottom surface 21a. Therefore, the culture solution β can be prevented from accumulating in the flow path 21.

[0052] Furthermore, in this hydroponic cultivation device 1, since the panel 9 having the planting holes 91 is disposed above the bottom surface 21a, crops can be planted at predetermined positions on the first liquid absorbing mat 6.

[0053] In addition, in this hydroponic cultivation device 1, since the planting holes 91 are located above the grooves 72, air can be passed through the lower surface 6a of the first liquid absorption mat 6 at a position facing the crop α. This makes it possible to increase the amount of oxygen supplied to the roots of the crop α via the first liquid absorption mat 6.

[0054] In addition, since the hydroponic cultivation device 1 includes the support device 3, the tank 2 can be easily installed so that the bottom surface 21a is inclined. Furthermore, since the supply device 4 and the recovery device 5 are provided, the culture solution β can be easily supplied to and recovered from the flow path 21.

[0055] In addition, in this hydroponic cultivation device 1, the apex 71a of each of the multiple peaks 71 has a tapered shape, which can reduce the contact area between the drainage promotion member 7 and the first liquid absorption mat 6. This improves the breathability in the vicinity of the lower surface 6a of the first liquid absorption mat 6, so that the amount of oxygen supplied to the roots of the crop α via the first liquid absorption mat 6 can be increased.

[0056] In addition, in this hydroponic cultivation device 1, the groove portion 72 has the first groove portion 74 that extends in the extension direction D1 of the flow path 21 and reaches both ends of the drainage promotion member 7 in the extension direction D1, so that the culture solution β can flow along the inclination of the bottom surface 21a on the drainage promotion member 7. This can improve the drainage property of the drainage promotion member 7.

[0057] In addition, in this hydroponic cultivation device 1, the groove portion 72 has the second groove portion 75 that extends in the width direction D2 of the flow path 21 and reaches both ends of the drainage promotion member 7 in the width direction D2, so that the culture solution β can flow in the width direction D2 on the drainage promotion member 7. This can improve the drainage property of the drainage promotion member 7.

[0058] In addition, in this hydroponic cultivation device 1, since the drainage promotion member 7 has the through-holes 73 formed in the grooves 72, the culture solution β flowing through the grooves 72 can be discharged to the outside of the grooves 72 at an earlier stage. This can improve the drainage properties of the drainage promotion member 7.

[0059] Furthermore, in this hydroponic cultivation device 1, the depth D of the groove portion 72 is 0.3 cm or more and 5 cm or less, preferably 0.4 cm or more and 3.5 cm or less, and more preferably 0.6 cm or more and 2 cm or less, so that the drainage performance of the drainage promotion member 7 can be improved while preventing the drainage promotion member 7 from becoming large.

[0060] Furthermore, in this hydroponic cultivation device 1, the thickness T of the drainage promotion member 7 is greater than 0.3 cm and less than 5.2 cm, preferably greater than 0.4 cm and less than 3.7 cm, and more preferably greater than 0.6 cm and less than 2.2 cm, thereby improving the drainage properties of the drainage promotion member 7 while preventing the drainage promotion member 7 from becoming larger.

[0061] In addition, in this hydroponic cultivation device 1, the first liquid absorption mat 6, the drainage promotion member 7, and the second liquid absorption mat 8 are located closer to the side surface 21b of the flow path 21, so that the width of the flow path between the first liquid absorption mat 6, the drainage promotion member 7, and the second liquid absorption mat 8 and the side surface 21c becomes wider. This reduces the flow resistance of the culture solution β flowing on the bottom surface 21a, so that the culture solution β can be prevented from accumulating in the flow path 21.

[0062] In the hydroponic cultivation method of this embodiment, by repeating the supply process and the stop process, it is possible to continuously supply the culture solution to the roots of crop α from the first liquid absorption mat 6 while intermittently supplying oxygen to the roots of crop α below the first liquid absorption mat, thereby enabling a stable supply of culture solution and oxygen to the roots of crop α.

[0063] [Second embodiment] Next, a second embodiment will be described. The second embodiment is basically the same as the first embodiment, and differs from the first embodiment only in that the hydroponic cultivation device does not include the second liquid-absorbing mat. Therefore, only the differences from the first embodiment will be described below, and the same points as the first embodiment will be omitted.

[0064] Fig. 10 is a cross-sectional view of a hydroponic cultivation apparatus according to a second embodiment. As shown in Fig. 10, a hydroponic cultivation apparatus 1A according to this embodiment includes a tank 2, a support device 3, a supply device 4, a recovery device 5, a first liquid-absorbing mat 6, a drainage promotion member 7, and a panel 9, but does not include a configuration corresponding to the second liquid-absorbing mat 8 of the hydroponic cultivation apparatus 1 according to the first embodiment. In other words, the drainage promotion member 7 is disposed directly above the bottom surface 21a of the tank 2, and no liquid-absorbing mat is disposed between the bottom surface 21a and the drainage promotion member 7.

[0065] The hydroponic cultivation method according to the second embodiment is similar to the hydroponic cultivation method according to the first embodiment, except that the hydroponic cultivation apparatus 1A is used instead of the hydroponic cultivation apparatus 1.

[0066] In this manner, in the hydroponic cultivation apparatus 1A according to the present embodiment, the drainage promotion member 7 is disposed directly above the bottom surface 21a, and no liquid-absorbing mat is disposed between the bottom surface 21a and the drainage promotion member 7. Therefore, when the supply of the culture solution β to the flow path 21 is stopped, the culture solution β can be quickly drained even between the bottom surface 21a and the drainage promotion member 7. Therefore, even if a root mat of the roots of the crop α is formed between the bottom surface 21a and the drainage promotion member 7, stopping the supply of the culture solution β to the flow path 21 quickly improves the breathability of the root mat, and oxygen can be supplied to the root mat.

[0067] [Third embodiment] Next, a third embodiment will be described. The third embodiment is basically the same as the first embodiment, and differs from the first embodiment only in that the hydroponic cultivation device further includes a root-proof water-permeable sheet. Therefore, only the differences from the first embodiment will be described below, and the same points as the first embodiment will be omitted.

[0068] Fig. 11 is a cross-sectional view of a hydroponic cultivation device according to a third embodiment. As shown in Fig. 11, a hydroponic cultivation device 1B according to this embodiment includes a tank 2, a support device 3, a supply device 4, a recovery device 5, a first liquid-absorbent mat 6, a drainage promotion member 7, a second liquid-absorbent mat 8, a panel 9, and a root-barrier water-permeable sheet 10.

[0069] The root-proof and water-permeable sheet 10 is a sheet that allows the permeation of liquids such as the nutrient solution β while preventing the penetration of the roots of the crop α. The root-proof and water-permeable sheet 10 is attached to the tank 2 so as to divide the space in the flow path 21 into an area including the bottom surface 21a and the drainage promotion member 7 and an area not including the bottom surface 21a and the drainage promotion member 7. More specifically, the root-proof and water-permeable sheet 10 passes between the drainage promotion member 7 and the first liquid-absorbing mat 6, and both ends of the sheet are hung on the side walls 23 and 24. The root-proof and water-permeable sheet 10 is also sandwiched between the side walls 23 and 24 and the panel 9.

[0070] The hydroponic cultivation method according to the third embodiment is similar to the hydroponic cultivation method according to the first embodiment, except that the hydroponic cultivation apparatus 1B is used instead of the hydroponic cultivation apparatus 1.

[0071] Since the gap between the bottom surface 21a and the drainage promotion member 7 has poor breathability, oxygen deficiency is likely to occur when a root mat is formed. However, in the hydroponic cultivation device 1B according to the present embodiment, the root-proof water-permeable sheet 10 divides the space in the flow path 21 into an area including the bottom surface 21a and the drainage promotion member 7 and an area not including the bottom surface 21a and the drainage promotion member 7, so that the roots of the crop α can be prevented from growing between the bottom surface 21a and the drainage promotion member 7. This makes it possible to prevent a root mat from being formed between the bottom surface 21a and the drainage promotion member 7, resulting in oxygen deficiency.

[0072] [Fourth embodiment] Next, a fourth embodiment will be described. The fourth embodiment is basically the same as the third embodiment, and differs from the third embodiment only in the arrangement of the root-proof water-permeable sheet. Therefore, only the differences from the third embodiment will be described below, and the same points as the third embodiment will be omitted.

[0073] Fig. 12 is a cross-sectional view of a hydroponic cultivation device according to a fourth embodiment. As shown in Fig. 12, a hydroponic cultivation device 1C according to this embodiment includes a tank 2, a support device 3, a supply device 4, a recovery device 5, a first liquid-absorbent mat 6, a drainage promotion member 7, a second liquid-absorbent mat 8, a panel 9, and a root-barrier water-permeable sheet 10.

[0074] As in the third embodiment, the root-proof / water-permeable sheet 10 is attached to the tank 2 so as to divide the space within the flow path 21 into an area including the bottom surface 21a and the drainage promotion member 7 and an area not including the bottom surface 21a and the drainage promotion member 7. However, unlike the third embodiment, the root-proof / water-permeable sheet 10 passes over the first liquid-absorbing mat 6, and both ends thereof are hung on the side walls 23 and 24. Therefore, the crop α is placed on the root-proof / water-permeable sheet 10.

[0075] The hydroponic cultivation method according to the fourth embodiment is similar to the hydroponic cultivation method according to the third embodiment, except that the hydroponic cultivation apparatus 1C is used instead of the hydroponic cultivation apparatus 1B.

[0076] In this way, in the hydroponic cultivation apparatus 1C according to this embodiment, the root-proof water-permeable sheet 10 passes over the first liquid absorption mat 6, so that the roots of the crop α can be prevented from growing between the drainage promotion member 7 and the first liquid absorption mat 6. This prevents the formation of a root mat between the drainage promotion member 7 and the first liquid absorption mat 6, improving the breathability in the vicinity of the lower surface 6a of the first liquid absorption mat 6 and increasing the amount of oxygen supplied to the roots of the crop α through the first liquid absorption mat 6. Moreover, the root-proof water-permeable sheet 10 can be hung on the side walls 23 and 24 so as to cover the entire second liquid absorption mat 8, the drainage promotion member 7, and the first liquid absorption mat 6, so that the root-proof water-permeable sheet 10 can be easily installed.

[0077] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0078] For example, in the above embodiment, a single drainage promotion member is disposed between the bottom surface and the first absorbent mat, but multiple drainage promotion members may be disposed between the bottom surface and the first absorbent mat by stacking them together. In this case, the multiple drainage promotion members to be stacked together may be the same as each other or different from each other. [Explanation of symbols]

[0079] 1...hydroponic cultivation device, 1A...hydroponic cultivation device, 1B...hydroponic cultivation device, 1C...hydroponic cultivation device, 2...tank, 21...flow path, 21a...bottom surface, 21b...side surface, 21c...side surface, 21d...first end, 21e...second end, 22...bottom wall, 23...side wall, 24...side wall, 3...support device, 4...supply device, 4a...discharge port, 4b...supply pipe, 5...recovery device, 5a...recovery port, 5b...recovery pipe, 6...first liquid absorption mat, 6a...lower surface, 7...drainage promotion member, 71...ridge portion, 71a...top portion, 72...groove portion, 73...through hole, 74...first groove portion, 75...second groove portion, 8...second liquid absorption mat, 9...panel, 91...planting hole, 10...root-proof water-permeable sheet, D1...extension direction, D2...width direction, D3...height direction, α...crop, β...culture solution.

Claims

1. A vessel having a flow path; a first absorbent mat disposed on a bottom surface of the flow channel; a drainage promotion member disposed between the bottom surface and the first absorbent mat, the drainage promotion member having a plurality of ridges and grooves located between the plurality of ridges; Hydroponic cultivation equipment.

2. a panel disposed above the bottom surface and having an implantation hole; The hydroponic cultivation apparatus according to claim 1.

3. The planting hole is located above the groove portion. The hydroponic cultivation apparatus according to claim 2.

4. a support device for supporting the tank so that the bottom surface is inclined; A supply device for supplying a culture medium to the flow path; A recovery device for recovering the culture solution from the flow path is further provided. The hydroponic cultivation apparatus according to claim 1.

5. Each of the peaks has a tapered shape. The hydroponic cultivation apparatus according to claim 1.

6. The groove portion has a first groove portion extending in an extension direction of the flow path and reaching both ends of the drainage promotion member in the extension direction. The hydroponic cultivation apparatus according to claim 1.

7. The groove portion has a second groove portion extending in a width direction of the flow path and reaching both ends of the drainage promotion member in the width direction. The hydroponic cultivation apparatus according to claim 1.

8. The drainage promotion member has a through hole formed in the groove portion. The hydroponic cultivation apparatus according to claim 1.

9. The depth of the groove is 0.3 cm or more and 5 cm or less. The hydroponic cultivation apparatus according to claim 1.

10. The thickness of the drainage promotion member is more than 0.3 cm and not more than 5.2 cm. The hydroponic cultivation apparatus according to claim 1.

11. The first absorbent mat and the drainage promotion member are positioned to one side in the width direction of the flow path. The hydroponic cultivation apparatus according to claim 1.

12. Further, a second absorbent mat is disposed between the bottom surface and the drainage promotion member. The hydroponic cultivation apparatus according to claim 1.

13. Further provided is a root-proof water-permeable sheet that divides the space in the flow path into an area including the bottom surface and the drainage promotion member and an area not including the bottom surface and the drainage promotion member. The hydroponic cultivation apparatus according to claim 1.

14. A hydroponic cultivation method using the hydroponic cultivation device according to any one of claims 1 to 13, The tank is installed so that the bottom surface is inclined, and crops are placed on the first liquid absorbing mat; a supplying step of supplying a culture solution to the flow path and causing the first liquid-absorbent mat to absorb the culture solution, and a stopping step of stopping the supply of the culture solution to the flow path are repeated. Hydroponic cultivation methods.

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