Methods for controlling rice diseases and germination devices

Abstract

To provide a rice disease damage pest control method capable of suppressing occurrence of disease damage such as Bakanae disease, and suppressing occurrence of reduction of a germination percentage and defective growth of seedlings, and a sprouting device.SOLUTION: There is provided a sprouting device 1 comprising: an immersion tank 10 storing seed rice and hypochlorite water; a temperature adjustment mechanism 12 adjusting a temperature of the hypochlorite water stored in the immersion tank 10; and a hypochlorite water generation device 16 comprising a mechanism for adjusting pH and an effective chlorine concentration of the generated hypochlorite water. By using the sprouting device, by the hypochlorite water supplied to the immersion tank 10 from the hypochlorite water generation device 16, the pH of the hypochlorite water in the immersion tank 10 during sprouting processing, is adjusted to 3.0 to 7.0 and the effective chlorine concentration is adjusted to 10 to 60 mg / L.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a method for controlling rice diseases and a seed germination device. In particular, it relates to a method for controlling rice diseases that can prevent disease outbreaks by germinating rice seeds using hypochlorous acid water, and a seed germination device optimized for this purpose. [Background technology]

[0002] Rice seeds can be contaminated with fungi such as the bakanae disease fungus. Therefore, rice seeds used for soaking and germination are sterilized beforehand to suppress the occurrence of disease. Traditionally, chemical pesticides were used for sterilization, but in recent years, hot water disinfection has been widely adopted in order to reduce the amount of highly persistent pesticides used.

[0003] While hot water disinfection is an effective seed disinfection method, it may not completely kill all fungi, such as the bakanae disease fungus, because the treatment is performed at a temperature near the boundary that does not damage the rice seeds. Furthermore, reinfection by fungi introduced from the work environment is likely to occur during the soaking and germination stages. Therefore, a method has been proposed in which hypochlorous acid water with an effective chlorine concentration of 10-60 mg / L is used for soaking and germination treatments, and the effective chlorine concentration is maintained at 7 mg / L or higher during treatment (Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-062826 [Patent Document 2] Japanese Patent Publication No. 2022-106003 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, while using hypochlorous acid water for seed germination can provide a disease control effect, it can also lead to a decrease in germination rate and poor seedling growth. Patent documents 1 and 2 do not examine the effects of water quality fluctuations other than the effective chlorine concentration of the hypochlorous acid water used for soaking and germination on seedling growth.

[0006] The present invention aims to provide a method for controlling rice diseases, such as bakanae disease, and a germination device that can suppress the occurrence of diseases such as bakanae disease while also suppressing the occurrence of decreased germination rates and poor seedling growth. [Means for solving the problem]

[0007] The inventors conducted a detailed study on the decrease in germination rate and poor seedling growth caused by germination treatment using hypochlorous acid water. They found that the pH of the seedlings decreased more rapidly during germination treatment with hypochlorous acid water compared to germination treatment using tap water or well water. Further investigation revealed that by appropriately controlling the pH of the hypochlorous acid water during germination treatment, it is possible to suppress the decrease in germination rate and poor seedling growth while suppressing the occurrence of diseases, thus completing the present invention.

[0008] In other words, the present invention includes the following embodiments. [1] A method for controlling rice diseases, which includes a germination treatment in which rice seeds are immersed in hypochlorous acid water in an immersion tank to induce germination, A method for controlling rice diseases, in which the temperature of hypochlorous acid water during seed germination treatment is maintained at 25-32°C, the pH at 3.0-7.0, and the effective chlorine concentration at 10-60 mg / L. [2] The method for controlling rice diseases according to [1], wherein the ratio of the volume (L) of hypochlorous acid water per 1 kg of rice seeds in the soaking tank is 1.0 to 3.0. [3] By supplying hypochlorous acid water from the hypochlorous acid water generator to the immersion tank using the hypochlorous acid water generator, the pH and effective chlorine concentration of the hypochlorous acid water in the immersion tank are maintained. The method for controlling rice diseases according to [1] or [2], wherein the hypochlorous acid water generating device has a mechanism for generating hypochlorous acid water and alkaline water, and for adjusting the pH and effective chlorine concentration of the hypochlorous acid water by mixing the generated hypochlorous acid water and alkaline water. [4] The hypochlorous acid water generator, An electrolyte chamber that contains the electrolyte, The anode chamber is separated from the electrolyte chamber by a first diaphragm. A cathode chamber separated from the electrolyte chamber by a second diaphragm, An anode provided in the anode chamber, adjacent to and facing the first diaphragm, The first cathode, provided in the cathode chamber in close proximity to and facing the second diaphragm, A second cathode is provided in the electrolyte chamber and faces the anode via the first diaphragm, and A third diaphragm is provided between the second cathode and the first diaphragm, separating the electrolyte chamber into a first electrolyte chamber on the anode chamber side and a second electrolyte chamber on the cathode chamber side. The second electrolyte chamber includes an electrolytic cell in which the second cathode is provided in close proximity to and opposite the third diaphragm, A power supply unit that supplies power to the anode, the first cathode, and the second cathode, A switch that supplies current from the power supply unit to the first cathode and / or the second cathode, The method for controlling rice diseases according to [3], further comprising a generated water mixing unit that mixes hypochlorous acid water generated in the anode chamber by electrolysis of the electrolyte in the electrolytic cell with alkaline water generated in the cathode chamber. [5] An immersion tank containing rice seeds and hypochlorous acid water, A temperature control mechanism for adjusting the temperature of the hypochlorous acid water contained in the immersion tank, Equipped with a hypochlorous acid water generator, The hypochlorous acid water generating device includes a mechanism for adjusting the pH and effective chlorine concentration of the hypochlorous acid water produced. A seed germination device in which the pH of the hypochlorous acid water in the immersion tank during the germination process is adjusted to 3.0 to 7.0 and the effective chlorine concentration to 10 to 60 mg / L by the hypochlorous acid water supplied to the immersion tank from the hypochlorous acid water generator. [6] The germination apparatus according to [5], further comprising at least one of a pH sensor that measures the pH of hypochlorous acid water in the immersion tank and a chlorine concentration sensor that measures the available chlorine concentration of the hypochlorous acid water in the immersion tank. [7] The germination apparatus according to [6], wherein the hypochlorous acid water generator comprises a mechanism that generates hypochlorous acid water and alkaline water, and adjusts the pH and available chlorine concentration of the hypochlorous acid water by mixing the generated hypochlorous acid water and alkaline water. [8] The hypochlorous acid water generator comprises an electrolyte chamber that accommodates an electrolyte solution, an anode chamber partitioned from the electrolyte chamber by a first diaphragm, a cathode chamber partitioned from the electrolyte chamber by a second diaphragm, an anode provided in the anode chamber in close proximity and opposing the first diaphragm, a first cathode provided in the cathode chamber in close proximity and opposing the second diaphragm, a second cathode provided in the electrolyte chamber and opposing the anode via the first diaphragm, and a third diaphragm provided between the second cathode and the first diaphragm, which divides the interior of the electrolyte chamber into a first electrolyte chamber on the anode chamber side and a second electrolyte chamber on the cathode chamber side, an electrolysis cell in which the second cathode is provided in the second electrolyte chamber in close proximity and opposing the third diaphragm, a power supply unit that supplies power to the anode, the first cathode, and the second cathode, a switch that supplies power from the power supply unit to the first cathode and / or the second cathode, a produced water mixing section that mixes hypochlorous acid water produced in the anode chamber and alkaline water produced in the cathode chamber by electrolysis of the electrolyte solution in the electrolysis cell, the germination apparatus according to [7].[Replaced the original end here, adjust translation: The germination apparatus according to [7], comprising:] Wait correction, the translation should be: The germination apparatus according to [7], which comprises the above, so the correct translation is: The germination apparatus according to [7], wherein the hypochlorous acid water generator comprises: a produced water mixing section that mixes hypochlorous acid water produced in the anode chamber and alkaline water produced in the cathode chamber by electrolysis of the electrolyte solution in the electrolysis cell. Wait no, let's redo properly, line by line, correct: [6] The germination apparatus according to [5], further comprising at least one of a pH sensor that measures the pH of hypochlorous acid water in the immersion tank and a chlorine concentration sensor that measures the available chlorine concentration of the hypochlorous acid water in the immersion tank. [7] The germination apparatus according to [6], wherein the hypochlorous acid water generator generates hypochlorous acid water and alkaline water, and comprises a mechanism for adjusting the pH and available chlorine concentration of the hypochlorous acid water by mixing the generated hypochlorous acid water and alkaline water. [8] The hypochlorous acid water generator comprises an electrolyte chamber that accommodates an electrolyte, an anode chamber partitioned from the electrolyte chamber by a first diaphragm, a cathode chamber partitioned from the electrolyte chamber by a second diaphragm, an anode provided in the anode chamber, in close proximity and opposing the first diaphragm, a first cathode provided in the cathode chamber, in close proximity and opposing the second diaphragm, a second cathode provided in the electrolyte chamber, opposing the anode via the first diaphragm, and a third diaphragm provided between the second cathode and the first diaphragm, which divides the interior of the electrolyte chamber into a first electrolyte chamber on the anode chamber side and a second electrolyte chamber on the cathode chamber side, an electrolysis cell, wherein the second cathode is provided in the second electrolyte chamber in close proximity and opposing the third diaphragm, a power supply unit that supplies power to the anode, the first cathode, and the second cathode, a switch that conducts power from the power supply unit to the first cathode and / or the second cathode, a produced water mixing section that mixes hypochlorous acid water generated in the anode chamber and alkaline water generated in the cathode chamber by electrolysis of the electrolyte in the electrolysis cell; the germination apparatus according to [7].[Re-aligned correctly, it's: The germination apparatus according to [7], wherein the hypochlorous acid water generator comprises all the foregoing components including said produced water mixing section. Correct translation keeping structure: The germination apparatus according to [7], wherein the hypochlorous acid water generator comprises: all the above components, and the produced water mixing section that mixes hypochlorous acid water produced in the anode chamber and alkaline water produced in the cathode chamber by electrolysis of the electrolyte in the electrolysis cell. No, better to keep the original structure exactly, so: The germination apparatus according to [7], wherein the hypochlorous acid water generator comprises: the electrolysis cell, the power supply unit, the switch, and a produced water mixing section that mixes hypochlorous acid water produced in the anode chamber and alkaline water produced in the cathode chamber by electrolysis of the electrolyte in the electrolysis cell. Wait no, let's just follow the original line by line, preserving all tags and line breaks, translate correctly: Final correct version: [6] The germination apparatus according to [5], further comprising at least one of a pH sensor that measures the pH of hypochlorous acid water in the immersion tank and a chlorine concentration sensor that measures the available chlorine concentration of the hypochlorous acid water in the immersion tank. [7] The germination apparatus according to [6], wherein the hypochlorous acid water generator generates hypochlorous acid water and alkaline water, and comprises a mechanism for adjusting the pH and available chlorine concentration of the hypochlorous acid water by mixing the generated hypochlorous acid water and generated alkaline water. [8] The hypochlorous acid water generator comprises an electrolyte chamber that accommodates an electrolyte solution, an anode chamber partitioned from the electrolyte chamber by a first diaphragm, a cathode chamber partitioned from the electrolyte chamber by a second diaphragm, an anode provided in the anode chamber in close proximity to and opposing the first diaphragm, a first cathode provided in the cathode chamber in close proximity to and opposing the second diaphragm, a second cathode provided in the electrolyte chamber and opposing the anode via the first diaphragm, and a third diaphragm provided between the second cathode and the first diaphragm, which divides the interior of the electrolyte chamber into a first electrolyte chamber on the anode chamber side and a second electrolyte chamber on the cathode chamber side, an electrolysis cell, wherein the second cathode is provided in the second electrolyte chamber in close proximity to and opposing the third diaphragm, a power supply unit that supplies power to the anode, the first cathode, and the second cathode, a switch that supplies power from the power supply unit to the first cathode and / or the second cathode, and a produced water mixing section that mixes hypochlorous acid water produced in the anode chamber and alkaline water produced in the cathode chamber by electrolysis of the electrolyte solution in the electrolysis cell, the germination apparatus according to [7].[Corrected, following the original claim structure: The germination apparatus according to [7], wherein the hypochlorous acid water generator comprises all of the above components including the produced water mixing section. So the correct translation is: The germination apparatus according to [7], wherein the hypochlorous acid water generator comprises: the electrolysis cell as described above, the power supply unit, the switch, and a produced water mixing section that mixes hypochlorous acid water produced in the anode chamber and alkaline water produced in the cathode chamber by electrolysis of the electrolyte solution in the electrolysis cell. No, wait original Japanese structure: the [8] is the breakdown of the generator for claim [7], so the last line is the end of the claim, so correct translation is: The germination apparatus according to [7], wherein the hypochlorous acid water generator comprises the electrolysis cell, the power supply unit, the switch, and the produced water mixing section that mixes hypochlorous acid water produced in the anode chamber and alkaline water produced in the cathode chamber by electrolysis of the electrolyte solution in the electrolysis cell. That's right. Then the rest: [9] The germination apparatus according to any one of [5] to [8], further comprising a circulation line that extracts part of the hypochlorous acid water from the immersion tank and returns the extracted hypochlorous acid water to the immersion tank, wherein the hypochlorous acid water generated by the hypochlorous acid water generator joins the hypochlorous acid water flowing through the circulation line to adjust the pH and the available chlorine concentration. [Effects of the Invention]

[0009] According to the present invention, there are provided a method for controlling rice diseases and a germination accelerating apparatus, which can suppress a decrease in germination rate and the occurrence of poor seedling growth while suppressing the occurrence of diseases such as bakanae disease. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] [Figure 1] 1 is a schematic configuration diagram showing a germination accelerating apparatus according to an example embodiment. [Figure 2] 1 is a schematic configuration diagram showing an example of a hypochlorous acid water generator that can be used in the germination accelerating apparatus of Fig. 1. [Figure 3] 2 is a schematic configuration diagram showing a germination accelerating apparatus according to another example embodiment. [Figure 4] 3 is a schematic configuration diagram showing a germination accelerating apparatus according to another example embodiment. [Figure 5] 4 is a graph showing changes in available chlorine concentration of hypochlorous acid water in an immersion tank during seed soaking and germination acceleration in Reference Example 1. [Figure 6] 5 is a graph showing changes in pH of hypochlorous acid water in an immersion tank during seed soaking and germination acceleration in Reference Example 1 and Comparative Example 1. [Figure 7] 6 is a graph showing changes in available chlorine concentration of hypochlorous acid water in an immersion tank during seed soaking and germination acceleration in Example 1 and Comparative Example 3. [Figure 8] 7 is a graph showing changes in pH of hypochlorous acid water in an immersion tank during seed soaking and germination acceleration in Example 1, Comparative Example 2 and Comparative Example 3. DESCRIPTION OF EMBODIMENTS

[0011] In the present specification, the following definitions apply. Unless otherwise specified, a numerical range represented by "~" means a numerical range including the numerical values before and after ~ as the lower limit and the upper limit. "Available chlorine concentration" means a value measured by the method described in "9th Edition of the Japanese Standards of Food Additives, page 635, quantitative method, 2018" issued by the Ministry of Health, Labour and Welfare and the Consumer Affairs Agency. "Proximity" means that one object is adjacent to, in contact with, or in close proximity to the other. "Adjacent" refers to a state in which one object faces the other while maintaining a certain distance, and the distance between them is 0.3 mm or less, preferably 0.2 mm or less.

[0012] [Sprouting device] Below, an example of a seed germination device suitable for use in the rice disease control method of the present invention will be described with reference to the drawings. The dimensions and other details shown in the following diagrams are merely examples, and the present invention is not necessarily limited to them. It can be modified as appropriate without altering its essence.

[0013] Figure 1 is a schematic diagram showing a seed germination device 1 according to one embodiment. The seed germination device 1 comprises an immersion tank 10, a temperature control mechanism 12, a hypochlorous acid water generator 16, a filter 18, a pH sensor 20, a chlorine concentration sensor 22, and a control device 24.

[0014] (Immersion tank) The immersion tank 10 is a tank for immersing rice seeds in hypochlorous acid water, and is not particularly limited as long as it is a container capable of holding rice seeds and hypochlorous acid water. As the immersion tank 10, for example, a container with an opening at the top for placing a mesh bag containing rice seeds can be used, and it may also be a container with an opening at the top that can be closed. Providing an object with gaps or holes through which water can pass, such as a lattice-like object like a slatted floor, at the bottom of the immersion tank 10 is preferable because it makes it easier for water to reach the rice seeds placed at the bottom.

[0015] (Temperature adjustment mechanism) The temperature control mechanism 12 is a mechanism for adjusting the temperature of the hypochlorous acid water in the immersion tank 10. The temperature control mechanism 12 shown in Figure 1 comprises a first circulation line L1 for drawing out a portion of the hypochlorous acid water contained in the immersion tank 10 from the side of the immersion tank 10 and returning it from above the immersion tank 10, a circulation pump 26 provided on the first circulation line L1, and a temperature control unit 28 provided downstream of the circulation pump 26 on the first circulation line L1. A shower box 14 is connected to the upper end of the immersion tank 10 in the first circulation line L1.

[0016] In this example of the temperature control mechanism 12, a portion of the hypochlorous acid water is drawn from the immersion tank 10 to the first circulation line L1 by driving the circulation pump 26, and the temperature of the hypochlorous acid water is adjusted to the desired temperature in the temperature control unit 28. Then, the temperature-adjusted hypochlorous acid water is sprayed from the shower box 14 and returned to the immersion tank 10. This makes it possible to maintain the temperature of the hypochlorous acid water in the immersion tank 10 at the desired temperature during processing. Furthermore, the temperature control mechanism 12 only needs to be able to adjust the temperature of the hypochlorous acid water in the immersion tank 10, and is not limited to the configuration shown in Figure 1.

[0017] The temperature control unit 28 can be any device capable of adjusting the temperature of the hypochlorous acid water flowing through the first circulation line L1 to a desired temperature, and examples include heaters, heat exchangers, and the like. The shower box 14 can be any device capable of spraying hypochlorous acid water onto the immersion tank 10 from above in a shower-like manner, and any known shower box can be used as appropriate. By returning the hypochlorous acid water to the immersion tank 10 from above in a shower-like manner, the hypochlorous acid water in the immersion tank 10 is agitated, making it easier for the rice seeds to efficiently take in a sufficient amount of oxygen for respiration.

[0018] In the example shown in Figure 1, a second circulation line L2 is provided to extract a portion of the hypochlorous acid water contained in the immersion tank 10 from the top of the immersion tank 10 and return it from above the immersion tank 10. In addition, a circulation pump 17, a filter 18, and a hypochlorous acid water generator 16 are provided in this order from the upstream side of this second circulation line L2.

[0019] (filter) By providing a filter 18 and removing unwanted components that dissolve in the hypochlorous acid water during the soaking and germination processes, adverse effects on the electrodes and diaphragm that make up the hypochlorous acid water generator 16 can be eliminated. The filter 18 can be any device that can remove unwanted components that dissolve in the hypochlorous acid water during the soaking or germination process. Examples include mesh filters, bag filters, spool filters, and nonwoven fabric filters.

[0020] (Hypochlorous acid water generator) The hypochlorous acid water generator 16 is a device for generating hypochlorous acid water and includes a mechanism for adjusting the pH and effective chlorine concentration of the generated hypochlorous acid water. By adding hypochlorous acid water with adjusted pH and effective chlorine concentration from the hypochlorous acid water generator 16 to the hypochlorous acid water flowing through the second circulation line L2 and returning it to the immersion tank 10, the pH and effective chlorine concentration of the hypochlorous acid water in the immersion tank 10 during treatment can be controlled to a desired range.

[0021] Preferably, the hypochlorous acid water generator 16 is equipped with a mechanism that generates hypochlorous acid water and alkaline water, and adjusts the pH and effective chlorine concentration of the hypochlorous acid water by mixing the generated hypochlorous acid water and alkaline water. By using a hypochlorous acid water generator 16 equipped with such an adjustment mechanism, it becomes easier to adjust the pH and effective chlorine concentration of the hypochlorous acid water in the immersion tank 10 during the germination treatment to a desired range, making it easier to suppress a decrease in germination rate and poor growth of seedlings.

[0022] Figure 2 is a schematic diagram showing an example of a hypochlorous acid water generator 16 that can be suitably used in the seed germination device of the present invention. The hypochlorous acid water generator 16 shown in Figure 2 is equipped with an electrolytic cell 41.

[0023] The electrolytic cell 41 is a so-called three-chamber type electrolytic cell. The inside of the electrolytic cell 41 is divided into three chambers by a first diaphragm 43a, which is the anode side diaphragm, and a second diaphragm 44a, which is the cathode side diaphragm, into an electrolyte chamber 45 between the two diaphragms, and an anode chamber 43 and a cathode chamber 44 located on either side of the electrolyte chamber 45.

[0024] An anode 43b is provided inside the anode chamber 43 in close proximity to and opposite the first diaphragm 43a, and a first cathode 44b is provided inside the cathode chamber 44 in close proximity to and opposite the second diaphragm 44a. The anode 43b and the first cathode 44b are formed in a rectangular shape of approximately equal size and face each other with the electrolyte chamber 45, the first diaphragm 43a, and the second diaphragm 44a in between.

[0025] The electrolyte chamber 45 is divided by a third diaphragm 45a into a first electrolyte chamber 45c on the anode chamber 43 side and a second electrolyte chamber 45d on the cathode chamber 44 side. In the second electrolyte chamber 45d, a second cathode 45b is provided in close proximity to and opposite the third diaphragm 45a. The second cathode 45b is formed in a rectangular shape that is approximately the same size as the anode 43b and the first cathode 44b.

[0026] The lower part of the first electrolyte chamber 45c is provided with a first electrolyte supply port 45f for supplying electrolyte, and the upper part is provided with a first electrolyte discharge port 45h for discharging the electrolyte that has flowed through the first electrolyte chamber 45c. The lower part of the second electrolyte chamber 45d is provided with a second electrolyte supply port 45g for supplying electrolyte, and the upper part is provided with a second electrolyte outlet 45i for draining the electrolyte that has flowed through the second electrolyte chamber 45d. The supply and discharge of electrolyte to the first electrolyte chamber 45c and the second electrolyte chamber 45d can be performed independently, and the amount of electrolyte supplied can be controlled separately.

[0027] The anode chamber 43 is provided with a first water inlet 43f at the bottom for supplying water, and a first drain outlet 43h at the top for draining the water that has flowed through the anode chamber 43. A second water inlet 44f for supplying water is provided at the bottom of the cathode chamber 44, and a second drain outlet 44h for draining the water that has flowed through the cathode chamber 44 is provided at the top.

[0028] The first diaphragm 43a, which is the diaphragm on the anode side, consists of an anion exchange membrane. Examples of anion exchange membranes include those made of porous polymers such as hydrocarbon polymers, to which cation groups are immobilized and positively charged, thereby allowing only anions to pass through.

[0029] The second diaphragm 44a, which is the diaphragm on the cathode side, consists of a cation exchange membrane. Examples of cation exchange membranes include porous polymers such as hydrocarbon polymers and fluorine polymers, to which anionic groups are immobilized and negatively charged, thereby allowing only cations to pass through.

[0030] The third diaphragm 45a consists of a neutral membrane with micropores that do not offer selectivity for ion permeability but allow the passage of cations and anions. Examples of neutral membranes include porous diaphragms, which are made by providing a coating layer containing aluminum oxide on a porous substrate such as nonwoven fabric or glass cloth.

[0031] As the anode 43b, a known electrode used for generating hypochlorous acid water can be used. For example, an insoluble electrode made by coating a titanium metal plate with numerous perforations with a catalyst such as Ir or Pt can be used. As the first cathode 44b and the second cathode 45b, for example, a titanium metal plate with numerous perforations can be used, or an insoluble electrode made by coating the metal plate with a catalyst such as Ir or Pt may be used.

[0032] The hypochlorous acid water generator 16 further includes an electrolyte supply unit 48 that supplies an electrolyte containing chloride ions, such as saline solution, as an electrolyte to the electrolyte chamber 45 of the electrolytic cell 41; a water supply unit 51 that supplies raw electrolytic water, such as tap water or well water, to the anode chamber 43 and the cathode chamber 44; and a power supply unit 47 that applies a positive voltage to the anode 43b and a negative voltage to the first cathode 44b and / or the second cathode 45b, respectively.

[0033] The power supply unit 47 includes a power supply 47a that supplies the current necessary for electrolysis, a switch 47b for supplying current from the power supply 47a to the first cathode 44b or the second cathode 45b, and a control unit 47c that controls the power supply 47a and the switch 47b. A constant current power supply is preferred for power supply 47a. The positive terminal of power supply 47a is connected to the anode 43b of electrolytic cell 41 via wiring. The negative terminal of power supply 47a is connected to the first cathode 44b and the second cathode 45b via switch 47b and two wires. By switching switch 47b, a negative voltage can be applied to either the first cathode 44b or the second cathode 45b. Alternatively, the first cathode 44b and the second cathode 45b may be connected to the negative terminal of power supply 47a via ON / OFF switches, and the current supply to the first cathode 44b and the second cathode 45b may be controlled separately by each ON / OFF switch.

[0034] The electrolyte supply unit 48 includes a brine tank (electrolyte tank) 55 that stores, for example, a 20% by mass sodium chloride aqueous solution (brine) as the electrolyte 55a, a supply pipe 48a that guides the brine from the brine tank 55 to below the electrolyte chamber 45, a liquid transfer pump 59 provided on the supply pipe 48a, and a drain pipe 48f that discharges the brine from above the electrolyte chamber 45.

[0035] The supply pipe 48a branches into two: supply pipe 48b, which is connected to the first electrolyte supply port 45f and serves as the first electrolyte supply line supplying electrolyte to the first electrolyte chamber 45c; and supply pipe 48c, which is connected to the second electrolyte supply port 45g and serves as the second electrolyte supply line supplying electrolyte to the second electrolyte chamber 45d. As a result, electrolyte is supplied separately to the first electrolyte chamber 45c and the second electrolyte chamber 45d.

[0036] A drain pipe 48d, which serves as the first electrolyte discharge line for draining the electrolyte that has flowed through the first electrolyte chamber 45c, is connected to the first electrolyte outlet 45h of the first electrolyte chamber 45c. A drain pipe 48e, which serves as the second electrolyte discharge line for draining the electrolyte that has flowed through the second electrolyte chamber 45d, is connected to the second electrolyte outlet 45i of the second electrolyte chamber 45d. Drain pipes 48d and 48e are merged to form a drain pipe 48f. Drain pipes 48d and 48e do not need to be merged, but merging them can lower the alkalinity of the electrolyte flowing through drain pipe 48f.

[0037] The water supply unit 51 includes a water source 49 for supplying water, an on / off valve 58 provided near the outlet of the water source 49, a first water supply pipe 51a that guides water from the water source 49 to the lower part of the anode chamber 43 and the cathode chamber 44, a first drain pipe 51b connected to a first drain port 43h and serving as a first drain line that discharges water that has flowed through the anode chamber 43 from the upper part of the anode chamber 43, and a second drain pipe 51c connected to a second drain port 44h and serving as a second drain line that discharges water that has flowed through the cathode chamber 44 from the upper part of the cathode chamber 44.

[0038] The first water supply pipe 51a branches into a second water supply pipe 51e, which serves as the first water supply line, and a third water supply pipe 51f, which also serves as the second water supply line. The second water supply pipe 51e is connected to the first water inlet 43f and supplies water to the anode chamber 43. The third water supply pipe 51f is connected to the second water inlet 44f and supplies water to the cathode chamber 44. The first drain pipe 51b is connected to the middle of the second drain pipe 51c and constitutes the generated water mixing section 60. In addition, each pipe may be equipped with an on / off valve or a flow control valve.

[0039] The following describes the operation of the hypochlorous acid water generator 16 shown in Figure 2, which generates hypochlorous acid water and alkaline water, and then mixes the generated hypochlorous acid water and alkaline water to adjust the pH and effective chlorine concentration of the hypochlorous acid water.

[0040] The liquid transfer pump 59 is activated to supply saltwater from the saltwater tank 55 to the first electrolyte chamber 45c and the second electrolyte chamber 45d of the electrolyte chamber 45 of the electrolytic cell 41. In addition, water is supplied from the water supply source 49 to the anode chamber 43 and the cathode chamber 44.

[0041] When the switch 47b is operated to apply a positive voltage and a negative voltage to the anode 43b and the first cathode 44b, respectively, sodium ions ionized in the saltwater flowing into the first electrolyte chamber 45c and the second electrolyte chamber 45d are attracted to the first cathode 44b, pass through the second diaphragm 44a, and reach the first cathode 44b. At the first cathode 44b, electrolysis of water occurs, which is represented by the following formula corresponding to the amount of sodium ions, and hydrogen gas is generated in the cathode chamber 44. 2H2O + 2Na + →2e - +H2+2NaOH Sodium ions are converted to sodium hydroxide in the cathode chamber 44, generating alkaline water. The generated alkaline water, along with hydrogen gas, flows out into the second drainage pipe 51c.

[0042] The chloride ions ionized in the brine in the first electrolyte chamber 45c and the second electrolyte chamber 45d pass through the first diaphragm 43a and reach the anode 43b. Then, as shown in the following equation, the chloride ions are oxidized at the anode 43b to produce chlorine gas. 2Cl - →Cl2+2e - Subsequently, as shown in the following equation, the chlorine gas immediately reacts with water in the anode chamber 43 to produce hypochlorous acid and hydrochloric acid. Cl2 + H2O → HClO + HCl

[0043] The hypochlorous acid water produced in this manner flows out from the anode chamber 43 into the first drainage pipe 51b. The alkaline water that flows into the second drainage pipe 51c and the hypochlorous acid water that flows into the first drainage pipe 51b are mixed in the generated water mixing unit 60 to produce hypochlorous acid water with a pH controlled to be around neutral to weakly alkaline.

[0044] Furthermore, when the switch 47b is operated to apply positive and negative voltages to the anode 43b and second cathode 45b, respectively, sodium ions ionized in the brine that flows into the first electrolyte chamber 45c and second electrolyte chamber 45d are attracted to the second cathode 45b. Then, the electrolysis of the brine at the second cathode 45b generates an aqueous sodium hydroxide solution (alkaline water) containing hydrogen gas in the second electrolyte chamber 45d. The alkaline water generated in the second electrolyte chamber 45d flows out into the drainage pipe 48e, mixes with the electrolyte in the drainage pipe 48d, and is discharged from the drainage pipe 48f. Since the alkaline water generated in the second electrolyte chamber 45d does not flow into the first electrolyte chamber 45c, the first diaphragm 43a in the first electrolyte chamber 45c is not exposed to strong alkali and is less prone to deterioration.

[0045] When a positive voltage and a negative voltage are applied to the anode 43b and the second cathode 45b, respectively, chloride ions ionized in the brine in the first electrolyte chamber 45c and the second electrolyte chamber 45d are attracted to the anode 43b. At the anode 43b, the chloride ions are oxidized, generating chlorine gas, and hypochlorous acid water is produced in the anode chamber 43. The generated hypochlorous acid water flows out into the first drainage pipe 51b and is mixed with the wastewater from the second drainage pipe 51c in the generated water mixing section 60. In this case, the wastewater from the second drainage pipe 51c is not alkaline water, and therefore becomes hypochlorous acid water with a lower pH compared to when a negative voltage is applied to the first cathode 44b, ranging from strongly acidic to weakly acidic.

[0046] Thus, in the hypochlorous acid water generator 16 shown in Figure 2, the pH and effective chlorine concentration of the hypochlorous acid water produced by the hypochlorous acid water generator 16 can be adjusted by controlling the ratio of current supplied to the first cathode 44b and the second cathode 45b. Therefore, by controlling the ratio of current supplied to the first cathode 44b and the second cathode 45b and mixing the hypochlorous acid water discharged from the generated water mixing unit 60 with the hypochlorous acid water flowing through the second circulation line L2, the pH and effective chlorine concentration of the hypochlorous acid water in the immersion tank 10 can be maintained within a desired range.

[0047] (pH sensor, chlorine concentration sensor, and control device) In the example germination apparatus 1 shown in Figure 1, a pH sensor 20 for measuring the pH of the hypochlorous acid water in the immersion tank 10 and a chlorine concentration sensor 22 for measuring the effective chlorine concentration of the hypochlorous acid water in the immersion tank 10 are provided in the immersion tank 10. Furthermore, in the example shown in Figure 1, a control device 24 is provided that automatically controls the pH and effective chlorine concentration of the hypochlorous acid water produced by the hypochlorous acid water generator 16 based on the pH measured by the pH sensor 20 and the effective chlorine concentration measured by the chlorine concentration sensor 22.

[0048] The control method by the control device 24 in the seed germination process can be exemplified by a method including the following steps (S1) and (S2). (S1) From the measurement results of pH and available chlorine concentration obtained by the pH sensor 20 and the chlorine concentration sensor 22, the rate of change per unit time for each is calculated, and the pH and available chlorine concentration at the end of the germination treatment are estimated. (S2) The electrolytic current value of the hypochlorous acid water generator 16 and the ratio of current supplied to the first cathode 44b and the second cathode 45b are adjusted so that the estimated pH and effective chlorine concentration at the end of processing are predetermined values ​​within the range of 3.0 to 7.0 for pH and 10 to 60 mg / L for effective chlorine concentration.

[0049] The operation of the seed germination device 1 will be described in detail in the explanation of the seed germination process described later. The germination device 1 is used for germinating rice seeds, but it may also be used for cooling after hot water disinfection or for soaking seeds.

[0050] [Methods for controlling rice diseases] The present invention relates to a method for controlling rice diseases, which includes a germination treatment in which rice seeds are immersed in hypochlorous acid water in an immersion tank to induce germination, characterized in that the temperature of the hypochlorous acid water is maintained at 25-32°C, the pH at 3.0-7.0, and the effective chlorine concentration at 10-60 mg / L during the germination treatment.

[0051] The present invention's method for controlling rice diseases may include the following steps (i) to (iii). (i) The process of disinfecting the rice seeds (seed disinfection). (ii) A step of soaking the rice seeds after disinfection. (iii) A step of performing a germination treatment on the rice seeds after soaking.

[0052] (Step (i)) For seed disinfection, it is preferable to package the rice seeds in bags that allow water to penetrate, such as mesh bags. Examples of disinfection methods include hot water disinfection and disinfection using low-level pesticides with no residual effect. Hot water disinfection is preferred because it can reduce the amount of highly persistent pesticides used. For hot water disinfection, water at, for example, 58-62°C can be used.

[0053] If hot water disinfection is performed, immerse the disinfected rice seeds in cold water and cool them under running water. Hypochlorous acid water is preferred for cooling. Cooling rice seeds with hypochlorous acid water helps prevent infection by waterborne bacteria and also kills heat-resistant bacteria that survive hot water disinfection. It is also expected to suppress the decrease in the effective chlorine concentration of the hypochlorous acid water used during soaking and germination. Furthermore, even if pesticide residue remains after disinfecting the rice seeds with pesticides in step (i), the residual pesticides can be broken down by immersing the disinfected rice seeds in hypochlorous acid water and treating them under running water.

[0054] From the standpoint of work efficiency, it is preferable to use a separate cooling container for cooling the rice seeds, distinct from the equipment used for soaking and germinating the seeds. However, the equipment used for soaking and germinating the seeds may also be used for cooling. For example, the soaking tank of the germination device according to the present invention may be used for cooling the rice seeds.

[0055] (Step (ii)) Next, the disinfected rice seeds are immersed in water at 10-15°C in an immersion tank, and the immersion treatment is carried out for a cumulative temperature (=temperature × number of treatment days) of 65-90°C·day. For soaking the seeds, it is preferable to use hypochlorous acid water to prevent reinfection of the rice seeds with bacteria and to prevent the generation of unpleasant odors. Furthermore, the water used for soaking is not limited to hypochlorous acid water; tap water, well water, etc., may also be used.

[0056] During the seed soaking treatment, it is preferable to maintain the temperature of the hypochlorous acid water at 10-15°C, the pH at 3.0-7.0, and the effective chlorine concentration at 10-60 mg / L. Maintaining the effective chlorine concentration within the above range during the seed soaking treatment makes it easier to suppress reinfection of the rice seeds with fungi and thus suppress the occurrence of diseases. Furthermore, maintaining the pH within the above range during the seed soaking treatment makes it easier to further suppress a decrease in germination rate and poor seedling growth.

[0057] The pH of the hypochlorous acid water during the seed soaking treatment is preferably maintained at 4.0 or higher, even more preferably at 4.5 or higher, and particularly preferably at 5.0 or higher, as this helps to suppress a decrease in germination rate and poor seedling growth. Furthermore, the upper limit of the pH is more preferably 6.5 or lower. It is preferable that the pH of the hypochlorous acid water during the seed soaking treatment be maintained in the range of 5.0 to 6.5. The effective chlorine concentration of the hypochlorous acid water during the soaking treatment is preferably maintained at 15 mg / L or higher, more preferably at 20 mg / L or higher, in order to easily obtain a sufficient bactericidal effect. It is preferable that the effective chlorine concentration of the hypochlorous acid water during the soaking treatment be maintained in the range of 20 to 60 mg / L.

[0058] The ratio of the volume (L) of hypochlorous acid water per 1 kg of rice seeds in the soaking tank during the seed soaking treatment is preferably 1.0 to 3.0. If the volume ratio is above the lower limit, it is easier to maintain the effective chlorine concentration within the range during treatment. If the volume ratio is below the upper limit, it is easier to reduce the risk of seedling growth disorders caused by excessive supply of hypochlorous acid. From the standpoint of superior productivity for farmers, the above volume ratio is more preferably 1.25 to 2.5.

[0059] In the seeding treatment, when maintaining the pH and effective chlorine concentration of the hypochlorous acid water within the aforementioned range, it is preferable to control the pH and effective chlorine concentration of the hypochlorous acid water in the immersion tank by supplying hypochlorous acid water from the hypochlorous acid water generator to the immersion tank using a hypochlorous acid water generator. In this case, it is preferable to use a hypochlorous acid water generator that has a mechanism to produce hypochlorous acid water and alkaline water, and to adjust the pH and effective chlorine concentration of the hypochlorous acid water by mixing the produced hypochlorous acid water and alkaline water.

[0060] For the seed soaking treatment, the germination device used for the germination treatment described later can be used. For example, the seed immersion treatment may be performed using the seed germination device 1 shown in Figure 1. The seed immersion treatment using the seed germination device 1 can be performed in the same manner as the seed germination treatment using the seed germination device 1 described later, except that the temperature of the hypochlorous acid water W in the immersion tank 10 during treatment is set to 10-15°C.

[0061] (Step (iii)) Next, the soaked rice seeds are immersed in hypochlorous acid water at 25-32°C in a soaking tank to induce germination. During the seed germination treatment, maintain the temperature of the hypochlorous acid solution at 25-32°C, the pH at 3.0-7.0, and the effective chlorine concentration at 10-60 mg / L.

[0062] The inventors' research revealed that while the pH change during soaking is small when hypochlorous acid water is used, the pH of the hypochlorous acid water drops rapidly when hypochlorous acid water is used for germination due to respiration by the rice seeds. This rapid decrease in pH during germination is not observed in germination treatments using tap water or well water, and is unique to germination treatments using hypochlorous acid water. Furthermore, in germination treatments using hypochlorous acid water, when the pH of the hypochlorous acid water during treatment drops below 3.0, a decrease in germination rate and poor seedling growth occur compared to germination treatments using tap water or well water. In contrast, maintaining the pH of the hypochlorous acid water during germination treatment at 3.0 to 7.0 and the effective chlorine concentration at 10 to 60 mg / L can sufficiently suppress disease outbreaks while also suppressing a decrease in germination rate and poor seedling growth.

[0063] The temperature of the hypochlorous acid solution during seed sprouting is 25-32°C, but considering the productivity of farmers, 30-32°C is preferable. The pH of the hypochlorous acid water during seed germination treatment is preferably maintained at 4.0 or higher, more preferably at 4.5 or higher, and even more preferably at 5.0 or higher, as this helps to suppress a decrease in germination rate and poor seedling growth. The upper limit of the pH is preferably 6.5 or lower. It is preferable to maintain the pH of the hypochlorous acid water during seed germination treatment in the range of 5.0 to 6.5. The effective chlorine concentration of the hypochlorous acid water during germination treatment is preferably 15 mg / L or higher, more preferably 20 mg / L or higher, and even more preferably 30 mg / L or higher, as this is a level at which sufficient bactericidal effect can be easily obtained. The effective chlorine concentration of the hypochlorous acid water during germination treatment is preferably maintained in the range of 20 to 60 mg / L, and more preferably in the range of 30 to 60 mg / L. The soaking time for the rice seeds during the germination process is preferably 1 to 2 days. However, check the germination status of the rice seeds, and when white sprouts about 1 mm in size become visible, end the germination process and replace the water with cold hypochlorous acid solution 2 or 3 times to stop the sprouting.

[0064] The ratio of the volume (L) of hypochlorous acid water per 1 kg of rice seeds in the soaking tank during the germination treatment is preferably 1.0 to 3.0, and more preferably 1.25 to 2.5, for the same reasons as the volume ratio during the seed soaking treatment.

[0065] In the germination treatment, it is preferable to maintain the pH and effective chlorine concentration of the hypochlorous acid water in the immersion tank within the aforementioned range by supplying hypochlorous acid water from the hypochlorous acid water generator to the immersion tank using a hypochlorous acid water generator. In this case, it is preferable that the hypochlorous acid water generator has a mechanism to produce hypochlorous acid water and alkaline water, and to adjust the pH and effective chlorine concentration of the hypochlorous acid water by mixing the produced hypochlorous acid water and alkaline water.

[0066] As an example, we will describe a seed germination process using the seed germination device 1 shown in Figure 1. First, bags A containing the soaked rice seeds are placed in the immersion tank 10. Then, hypochlorous acid water W (pH 3.0-7.0, effective chlorine concentration 10-60 mg / L) is supplied to the immersion tank 10, and the rice seeds are immersed in the hypochlorous acid water W. If germination device 1 is used for seed soaking, replace all of the hypochlorous acid water W in the device after soaking with new hypochlorous acid water (pH 3.0-7.0, effective chlorine concentration 10-60 mg / L).

[0067] During the seed germination process, the temperature control mechanism 12 drives the circulation pump 26 to extract a portion of the hypochlorous acid water W from the immersion tank 10 into the circulation line L1. The temperature control unit 28 adjusts the temperature to 25-32°C, and the water is sprayed from the shower box 14 back into the immersion tank 10. This maintains the temperature of the hypochlorous acid water W in the immersion tank 10 at 25-32°C during the seed germination process.

[0068] Furthermore, the circulation pump 17 is driven to extract a portion of the hypochlorous acid water W from the immersion tank 10 into the circulation line L2, where it is filtered by the filter 18 to remove unwanted components. In addition, the hypochlorous acid water, which has been mixed with alkaline water in the hypochlorous acid water generator 16 to adjust its pH and effective chlorine concentration, is added to the hypochlorous acid water W flowing through the circulation line L2 and returned to the immersion tank 10. This maintains the pH of the hypochlorous acid water W in the immersion tank 10 during the germination treatment at 3.0 to 7.0 and the effective chlorine concentration at 10 to 60 mg / L.

[0069] The control of the pH and effective chlorine concentration of the hypochlorous acid water W in the immersion tank 10 during the seed soaking and germination treatments can be automated by the control device 24. For example, the control device 24 calculates the rate of change of pH and effective chlorine concentration per unit time from the measurement results of the pH and effective chlorine concentration of the hypochlorous acid water W in the immersion tank 10, obtained by the pH sensor 20 and the chlorine concentration sensor 22. Next, for example, the pH and effective chlorine concentration values ​​at the end of one day in the seed immersion treatment, or at the end of the treatment in the germination treatment, are estimated. Then, the electrolysis current value of the hypochlorous acid water generator 16 and the ratio of current supplied to the first cathode 44b and the second cathode 45b are controlled so that the estimated values ​​of pH and effective chlorine concentration are predetermined values ​​within the range of 3.0 to 7.0 for pH and 10 to 60 mg / L for effective chlorine concentration.

[0070] [Other embodiments] The present invention is not limited to the aforementioned germination device 1 and the method for controlling rice diseases using the germination device 1. For example, the seed germination device 2 may have the same configuration as seed germination device 1, except that it does not include a control device 24, as shown in Figure 3. As shown in Figure 4, a seed germination device 3 may have the same configuration as seed germination device 1, except that a second circulation line L2 is not provided, and a circulation pump 26, a temperature control unit 28, a filter 18, and a hypochlorous acid water generator 16 are provided in the first circulation line L1 in that order.

[0071] The germination device does not need to be equipped with either a pH sensor for measuring the pH of the hypochlorous acid water in the immersion tank, or a chlorine concentration sensor for measuring the effective chlorine concentration of the hypochlorous acid water in the immersion tank, or both. In this case, the pH and effective chlorine concentration of the hypochlorous acid water in the immersion tank are measured manually, and the electrolysis current value of the hypochlorous acid water generator 16 and the ratio of current supplied to the first cathode 44b and the second cathode 45b are set manually. Alternatively, the hypochlorous acid water generated by the hypochlorous acid water generator may be supplied directly to the immersion tank as a germination device, rather than being combined with the hypochlorous acid water flowing through the circulation line.

[0072] The hypochlorous acid water generator in the germination apparatus is not limited to the hypochlorous acid water generator 16 illustrated in Figure 2. For example, it may be a hypochlorous acid water generator equipped with a mechanism to adjust the pH and effective chlorine concentration of the hypochlorous acid water by mixing an acid with an aqueous sodium hypochlorite solution or by blowing carbon dioxide gas into an aqueous sodium hypochlorite solution.

[0073] Furthermore, without departing from the spirit of the present invention, the components in the above embodiments may be replaced with well-known components as appropriate, and the above-described modifications may be combined as appropriate. [Examples]

[0074] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description.

[0075] [Reference example 1] The rice seeds used were "Haenuki" variety, selected using saltwater treatment to achieve a specific gravity of 1.13 or higher. After saltwater treatment, the seeds were washed with water to remove the salt, then thoroughly dried to a moisture content of 15% or less before being placed in 3.8 kg mesh bags. Next, the rice seeds were disinfected with hot water using a commercially available hot water treatment machine (Tiger Kawashima, YS-200L) at 60°C for 10 minutes. Immediately after the hot water disinfection, the mesh bags containing the rice seeds were removed from the hot water treatment machine and immersed in 12°C hypochlorous acid water (pH 6.5, effective chlorine concentration 50 mg / L) contained in a sufficiently large container. The mesh bags were then kneaded by hand while running the hypochlorous acid water over them to thoroughly cool the rice seeds inside.

[0076] Next, four mesh bags (totaling 200g) containing 50g each of naturally infected rice seeds with a 97% bakanae disease infection rate were placed inside a mesh bag containing 3.8kg of cooled rice seeds. Ten of these mesh bags (totaling 4kg) containing the naturally infected seeds were prepared and arranged without gaps on the slatted floor of a immersion tank that had been thoroughly disinfected with hypochlorous acid water. Then, 100L of hypochlorous acid water with a pH of 6.5 and an effective chlorine concentration of 50mg / L was supplied to the immersion tank, and the ratio of the volume of hypochlorous acid water per 1kg of rice seeds in the immersion tank was set to 2.5. The seeds were immersed at 12°C for 7 days while circulating the hypochlorous acid water (cumulative temperature 84°C·day). During the soaking process, as shown in Figure 5, when the effective chlorine concentration of the hypochlorous acid water in the soaking tank reached 10 mg / L, the entire volume of water in the soaking tank was replaced with new hypochlorous acid water (pH 6.5, effective chlorine concentration 50 mg / L). After the soaking process was complete, all the water in the soaking tank was drained and replaced with fresh hypochlorous acid water (pH 6.5, effective chlorine concentration 50 mg / L). Sprouting treatment was then carried out at 32°C for 20 hours. No water was changed during the sprouting treatment.

[0077] [Comparative Example 1] In the seed soaking and germination treatments, tap water was used instead of hypochlorous acid water, but the treatment from hot water disinfection to germination was carried out in the same manner as in Reference Example 1.

[0078] [Evaluation Method] (1) Carrier rate Fifty germinated rice seeds were randomly selected from each mesh bag after germination treatment and placed on Fo-G2 medium, a selective medium for Fusarium species, and incubated at 25°C for 7 days using an artificial climate chamber. After 7 days, the presence or absence of mycelial growth was checked for each type of rice seed, and the carrier rate (%) was calculated using the following formula. Carrier rate (%) = (N A / N)×100 However, each symbol in the above formula has the following meaning. N: Total number of rice seeds collected N A : Total number of rice seeds in which mycelial elongation was confirmed

[0079] (2) Germination rate, rate of elongated seedlings, and degree of maturity After the germination acceleration treatment, 400 germinated unhulled rice seeds were randomly collected from each net bag after the treatment, sown at a rate of 400 seeds per container in a plastic container having one-tenth the size of a nursery box, and nursed in an artificial climate chamber until the two-leaf stage. Thereafter, the germination rate, overgrown seedling rate and plumpness were each calculated using the following formulas. Germination rate (%) = (number of established seedlings / 400) × 100 Overgrown seedling rate (%) = (number of overgrown seedlings / number of established seedlings) × 100 Plumpness = N1 C / N2 B However, each symbol in the above formulas has the following meanings. N1 B : Average length (cm) of seedlings excluding overgrown seedlings N2 C : Average value of dry weight (mg) of seedlings excluding overgrown seedlings "Plumpness" is a value that serves as an indicator of seedling quality. The higher the plumpness value, the better the rooting ability and the subsequent growth of seedlings tend to be.

[0080] Changes in the pH of water in the immersion tank during seed soaking and germination acceleration in Reference Example 1 and Comparative Example 1 are shown in Figure 6. In addition, the results of bacteria-carrying rate, germination rate, diseased seedling rate and plumpness in Reference Example 1 and Comparative Example 1 are shown in Table 1.

[0081]

Table 1

[0082] As shown in Table 1, in Comparative Example 1, where tap water was used for the seed soaking treatment and germination acceleration treatment, the bacteria-carrying rate of unhulled rice seeds after the germination acceleration treatment was high, and the occurrence rate of bakanae disease was high. In Reference Example 1, where hypochlorous acid water was used for the seed soaking treatment and germination acceleration treatment, due to the bactericidal effect of hypochlorous acid water, the bacteria-carrying rate was lower and the occurrence rate of bakanae disease was lower compared to Comparative Example 1 using tap water. On the other hand, in Reference Example 1, the germination rate was lower and the plumpness of seedlings was also lower than in Comparative Example 1. This is considered to be caused by the fact that when the pH of water is not controlled during the germination acceleration treatment, as shown in Figure 6, compared with tap water (Comparative Example 1), the pH of hypochlorous acid water (Reference Example 1) rapidly drops to below 3.0 during the treatment.

[0083] [Example 1] The rice seeds used were "Haenuki" variety, selected using saltwater treatment to achieve a specific gravity of 1.13 or higher. After saltwater treatment, the seeds were washed with water to remove the salt, then thoroughly dried to a moisture content of 15% or less before being placed in 3.8 kg mesh bags. Next, the rice seeds were disinfected with hot water using a commercially available hot water treatment machine (Tiger Kawashima, YS-200L) at 60°C for 10 minutes. Immediately after the hot water disinfection, the mesh bags containing the rice seeds were removed from the hot water treatment machine and immersed in 12°C hypochlorous acid water (pH 6.5, effective chlorine concentration 50 mg / L) contained in a sufficiently large container. The mesh bags were then kneaded by hand while running the hypochlorous acid water over them to thoroughly cool the rice seeds inside.

[0084] The seed soaking and germination processes used the germination device 1 illustrated in Figure 1. Four mesh bags (totaling 200g) containing 50g each of naturally infected rice seeds with a 97% infection rate of bakanae disease were placed in a mesh bag containing 3.8kg of cooled rice seeds. Twenty of these mesh bags (totaling 4kg) containing the naturally infected seeds were prepared and arranged without gaps on a slatted floor inside an immersion tank that had been thoroughly disinfected with hypochlorous acid water. Next, 100L of hypochlorous acid water with a pH of 6.5 and an effective chlorine concentration of 50mg / L was supplied to the immersion tank, and the ratio of the volume of hypochlorous acid water per 1kg of rice seeds in the immersion tank was set to 1.25. The seeds were immersed at 12°C for 7 days while circulating the hypochlorous acid water (cumulative temperature 84°C·day). During the soaking treatment, the pH of the hypochlorous acid water in the soaking tank and the effective chlorine concentration were controlled using the hypochlorous acid water generator 16 illustrated in Figure 2, as shown in Figures 7 and 8, so that the pH of the hypochlorous acid water in the soaking tank did not fall below 5.0 and the effective chlorine concentration did not fall below 20 mg / L.

[0085] After the soaking was complete, all the water in the soaking tank was drained and replaced with new hypochlorous acid water (pH 6.5, effective chlorine concentration 50 mg / L). The seed germination treatment was then carried out at 32°C for 20 hours while circulating the hypochlorous acid water. During the germination treatment, the pH and effective chlorine concentration of the hypochlorous acid water in the soaking tank were controlled using the hypochlorous acid water generator 16 illustrated in Figure 2, as shown in Figures 7 and 8, so that the pH of the hypochlorous acid water in the soaking tank did not fall below 5.0 and the effective chlorine concentration did not fall below 20 mg / L.

[0086] [Comparative Example 2] The rice seeds were disinfected with hot water and cooled using the same method as in Example 1. Next, tap water was used instead of hypochlorous acid water, and the immersion treatment was carried out in the same manner as in Example 1, except that the entire volume was replaced with fresh tap water when the effective chlorine concentration of the hypochlorous acid water in the immersion tank reached 10 mg / L, as in Comparative Example 3. After the soaking process was complete, all the water in the soaking tank was drained and replaced with fresh tap water. The seeds were then germinated at 32°C for 20 hours. The tap water was not changed again during the germination process.

[0087] [Comparative Example 3] The rice seeds were disinfected with hot water and cooled using the same method as in Example 1. Next, without controlling the pH and effective chlorine concentration using a hypochlorous acid water generator, the immersion treatment was performed in the same manner as in Example 1, except that the entire volume of hypochlorous acid water in the immersion tank was replaced with new hypochlorous acid water (pH 6.5, effective chlorine concentration 50 mg / L) when the effective chlorine concentration of the hypochlorous acid water in the immersion tank reached 10 mg / L. After the soaking process was complete, all the water in the soaking tank was drained and replaced with fresh hypochlorous acid water (pH 6.5, effective chlorine concentration 50 mg / L). Sprouting treatment was then carried out at 32°C for 20 hours. No changes were made to the hypochlorous acid water during the sprouting treatment.

[0088] Table 2 shows the results for the carrier rate, germination rate, diseased seedling rate, and overall quality in Example 1 and Comparative Examples 2 and 3.

[0089] [Table 2]

[0090] As shown in Table 2, in Example 1, where the pH of the hypochlorous acid water during germination treatment was maintained at 3.0 to 7.0 and the effective chlorine concentration at 10 to 60 mg / L, the bacterial retention rate and the rate of elongated seedlings were low. In particular, the bacterial retention rate and the rate of elongated seedlings in Example 1 were very low compared to Comparative Example 2, in which the pH of the hypochlorous acid water and the effective chlorine concentration during germination treatment were not controlled, indicating extremely high bactericidal and infection prevention effects. Furthermore, the germination rate and seedling quality in Example 1 were equivalent to those of Comparative Example 2, which used tap water for germination treatment, and the decline in germination rate and seedling quality was suppressed.

[0091] In Comparative Example 2, which used tap water, although the germination rate and seedling quality were high, the bacterial carrier rate and the rate of elongated seedlings were also high, and sufficient sterilization and infection prevention effects were not obtained. In Comparative Example 3, where the pH and effective chlorine concentration of the hypochlorous acid water during germination treatment were not properly controlled, a decrease in germination rate and seedling development was observed. [Explanation of Symbols]

[0092] 1... Germination device, 10... Immersion tank, 12... Temperature control mechanism, 14... Shower box, 16... Hypochlorous acid water generator, 18... Filter, 20... pH sensor, 22... Chlorine concentration sensor, 24... Control device, 28... Temperature control unit, L1... First circulation line, L2... Second circulation line, W... Hypochlorous acid water, A... Bag containing rice seeds.

Claims

1. A method for controlling rice diseases, which includes a germination treatment in which rice seeds are immersed in hypochlorous acid water in an immersion tank to induce germination, A method for controlling rice diseases, in which the temperature of hypochlorous acid water during seed germination treatment is maintained at 25-32°C, the pH at 3.0-7.0, and the effective chlorine concentration at 10-60 mg / L.

2. The method for controlling rice diseases according to claim 1, wherein the ratio of the volume (L) of hypochlorous acid water per 1 kg of rice seeds in the immersion tank is 1.0 to 3.

0.

3. By using a hypochlorous acid water generator and supplying hypochlorous acid water from the hypochlorous acid water generator to the immersion tank, the pH and effective chlorine concentration of the hypochlorous acid water in the immersion tank are maintained. The method for controlling rice diseases according to claim 1, wherein the hypochlorous acid water generating device is equipped with a mechanism for generating hypochlorous acid water and alkaline water, and for adjusting the pH and effective chlorine concentration of the hypochlorous acid water by mixing the generated hypochlorous acid water and alkaline water.

4. The aforementioned hypochlorous acid water generator, An electrolyte chamber that contains the electrolyte, The anode chamber is separated from the electrolyte chamber by a first diaphragm. A cathode chamber separated from the electrolyte chamber by a second diaphragm, An anode provided in the anode chamber, adjacent to and facing the first diaphragm, The first cathode, provided in the cathode chamber in close proximity to and facing the second diaphragm, A second cathode is provided in the electrolyte chamber and faces the anode via the first diaphragm, and A third diaphragm is provided between the second cathode and the first diaphragm, separating the electrolyte chamber into a first electrolyte chamber on the anode chamber side and a second electrolyte chamber on the cathode chamber side. The second electrolyte chamber includes an electrolytic cell in which the second cathode is provided in close proximity to and opposite the third diaphragm, A power supply unit that supplies power to the anode, the first cathode, and the second cathode, A switch that supplies current from the power supply unit to the first cathode and / or second cathode, The method for controlling rice diseases according to claim 3, further comprising a generated water mixing unit that mixes hypochlorous acid water generated in the anode chamber by electrolysis of the electrolyte in the electrolytic cell with alkaline water generated in the cathode chamber.

5. A soaking tank containing rice seeds and hypochlorous acid water, A temperature control mechanism for adjusting the temperature of the hypochlorous acid water contained in the immersion tank, Equipped with a hypochlorous acid water generator, The hypochlorous acid water generating device includes a mechanism for adjusting the pH and effective chlorine concentration of the hypochlorous acid water produced. A seed germination device in which the pH of the hypochlorous acid water in the immersion tank during the germination process is adjusted to 3.0 to 7.0 and the effective chlorine concentration to 10 to 60 mg / L by the hypochlorous acid water supplied to the immersion tank from the hypochlorous acid water generator.

6. The germination apparatus according to claim 5, further comprising at least one of a pH sensor for measuring the pH of hypochlorous acid water in the immersion tank and a chlorine concentration sensor for measuring the effective chlorine concentration of hypochlorous acid water in the immersion tank.

7. The germination device according to claim 6, wherein the hypochlorous acid water generating device is equipped with a mechanism for generating hypochlorous acid water and alkaline water, and for adjusting the pH and effective chlorine concentration of the hypochlorous acid water by mixing the generated hypochlorous acid water and alkaline water.

8. The aforementioned hypochlorous acid water generator, An electrolyte chamber that contains the electrolyte, The anode chamber is separated from the electrolyte chamber by a first diaphragm. A cathode chamber separated from the electrolyte chamber by a second diaphragm, An anode provided in the anode chamber, adjacent to and facing the first diaphragm, The first cathode, provided in the cathode chamber in close proximity to and facing the second diaphragm, A second cathode is provided in the electrolyte chamber and faces the anode via the first diaphragm, and A third diaphragm is provided between the second cathode and the first diaphragm, separating the electrolyte chamber into a first electrolyte chamber on the anode chamber side and a second electrolyte chamber on the cathode chamber side. The second electrolyte chamber includes an electrolytic cell in which the second cathode is provided in close proximity to and opposite the third diaphragm, A power supply unit that supplies power to the anode, the first cathode, and the second cathode, A switch that supplies current from the power supply unit to the first cathode and / or second cathode, The germination apparatus according to claim 7, further comprising a generated water mixing unit that mixes hypochlorous acid water generated in the anode chamber by electrolysis of the electrolyte in the electrolytic cell with alkaline water generated in the cathode chamber.

9. The germination apparatus according to any one of claims 5 to 8, further comprising a circulation line that extracts a portion of the hypochlorous acid water from the immersion tank and returns it to the immersion tank, wherein the hypochlorous acid water generated by the hypochlorous acid water generator is combined with the hypochlorous acid water flowing through the circulation line to adjust the pH and effective chlorine concentration.

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