Methane emission reduction device

Abstract

A methane generation reduction device is provided that can reduce the amount of methane generated by anaerobic fermentation in paddy field soil. [Solution] The methane generation reduction device of the present invention comprises a boat body 2 that floats on the water, a propulsion device 4 that propels the boat body, a control unit 22 that controls the unmanned navigation of the boat body on the water surface, a soil action unit 10 that is suspended from the boat body toward the soil on the water bottom, and an oxygen supply unit 12 that is suspended from the boat body toward the water.

Description

[Technical field]

[0001] This invention relates to a methane emission reduction device that reduces methane emission in rice paddies. [Background technology]

[0002] As shown in Patent Document 1, it is known that methane is emitted from paddy fields where rice is cultivated. In a flooded paddy field A, the oxygen in the water and soil is quickly used up by aerobic fermentation of organic matter. When oxygen is lacking in the soil, the amount of carbon dioxide and organic acids in the soil increases rapidly, and the lack of oxygen causes the organic matter in the soil to transition from aerobic fermentation to anaerobic fermentation, producing methane, ammonia, etc.

[0003] Methane generated in this way is known as a greenhouse gas, and there is a demand to curb its generation. According to a survey by the National Institute for Environmental Studies, it is said that approximately 40% of methane emissions in Japan come from rice paddies, and efforts are being made to reduce methane emissions from rice paddies. For example, in order to reduce methane emissions from rice paddies, it is being considered to extend the "mid-season drainage" period, during which water is drained from the paddies, thereby reducing the amount of methane generated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2024-048398 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a problem in that if the period during which water is drained from rice paddies is extended too long, it can have a negative impact on rice growth and reduce rice yields. Therefore, the inventors conducted intensive research into a device that could reduce methane emissions without extending the "mid-drying" period.

[0006] The present invention has been made to solve these problems, and its object is to provide a methane generation reduction device that can reduce the amount of methane generated by anaerobic fermentation in paddy field soil. [Means for solving the problem]

[0007] In order to achieve the above-mentioned objective, according to one embodiment of the present invention, a methane generation reduction device for reducing methane generation from rice paddy soil comprises a boat body that floats on the water, a propulsion device that propels the boat body, a control unit that controls the unmanned navigation of the boat body on the water surface, a soil action unit that is suspended from the boat body toward the soil at the bottom of the water, and an oxygen supply unit that is suspended from the boat body toward the water. According to one embodiment of the present technology configured in this manner, the boat includes a propulsion device for propelling the boat body, a control unit for controlling the unmanned navigation of the boat body on the water surface, a soil action unit suspended from the boat body toward the soil at the bottom of the water, and an oxygen supply unit suspended from the boat body toward the water. This allows the boat body to navigate unmanned on the water surface, and the soil action unit can act on the soil at the bottom of the water, for example, by stirring it, while the oxygen supply unit can supply oxygen. Therefore, the amount of methane generated by anaerobic fermentation in the soil of the paddy field can be reduced. In addition, the boat body can be navigated unmanned on the water surface, and methane generation reduction work can be efficiently performed on a relatively wide area of ​​paddy fields, without the worker having to work while walking back and forth in the mud of the paddy field. Therefore, heavy labor by the worker can be prevented. In addition, for example, the amount of methane generated from paddy fields can be reduced by implementing the present technology, even without extending the mid-drying period of the paddy field.

[0008] According to one embodiment of the present invention, preferably, the oxygen supply section is arranged to extend along the soil working section. According to one embodiment of the present technology configured as described above, the oxygen supply unit is arranged to extend along the soil action unit. This makes it easier for the oxygen supply unit to supply oxygen to the soil in accordance with the action of the soil action unit on the soil, for example, stirring. This makes it possible to further reduce the amount of methane generation in the soil of the paddy field.

[0009] According to one embodiment of the present invention, the oxygen supply preferably comprises a flexible air stone tube, the air stone tube extending along the soil working portion. According to one embodiment of the present technology configured as described above, the oxygen supply unit includes a flexible air stone tube. This allows the flexible air stone tube to easily follow the movement of the soil action unit. This allows the oxygen supply unit to more easily supply oxygen to the soil.

[0010] According to one embodiment of the present invention, preferably, the soil-working portion includes a plurality of cylindrical portions connected to each other, and is formed to be bendable at the connecting portions of the cylindrical portions. According to one embodiment of the present technology configured in this manner, the soil action part is formed by connecting a plurality of cylindrical parts in a series and being bendable. This makes it easier to stir the soil that has settled at the bottom of the paddy field by the ends of the cylinders, and also makes it easier for the soil action part to bend along the oxygen supply part. Even if the boat body is bent, the soil action part can be easily bent along the oxygen supply part, making it easier for the oxygen supply part to supply oxygen to the soil. This makes it possible to further reduce the amount of methane generated in the paddy field soil.

[0011] According to one embodiment of the present invention, preferably, the air stone tube of the oxygen supply section extends through the cylindrical section of the soil working section. According to one embodiment of the present technology configured in this manner, the air stone tube extends so as to pass through the cylindrical portion of the soil working part. This allows the soil working part to agitate the soil that has settled at the bottom of the paddy field while the air stone tube passing through the cylindrical portion can relatively efficiently introduce oxygen. In addition, the air stone tube is easily protected by the cylindrical portion during agitation, and the air stone tube is less likely to be damaged by rubbing against the soil, etc.

[0012] According to one embodiment of the present invention, preferably, a plurality of the soil action parts are attached in a line in the width direction of the boat body at the rear of the boat body, and the air stone tube is arranged so as to pass through the cylinder of the soil action part. According to one embodiment of the present technology configured in this manner, a plurality of the soil action parts are attached to the rear of the boat body in a line in the width direction of the boat body, and the air stone tube is arranged so as to pass through the cylinder of the soil action part. This allows the soil in the paddy field to be effectively stirred by arranging a plurality of soil action parts, and allows the air stone tube to be arranged together with each soil action part to efficiently supply oxygen to the soil. This further reduces the amount of methane generation in the paddy field soil.

[0013] According to an embodiment of the present invention, the oxygen supply unit preferably includes an air pump device for supplying air, and oxygen is supplied by the air supplied from the air pump device. According to one embodiment of the present technology configured as above, the oxygen supply unit includes an air pump device that supplies air, and oxygen is supplied by the air supplied from the air pump device. Therefore, it is possible to easily supply oxygen to the soil with a relatively simple configuration, and to further reduce the amount of methane generation in the soil of the paddy field.

[0014] According to one embodiment of the present invention, the propulsion device preferably comprises a plurality of propeller devices rotating in the air. According to one embodiment of the present technology configured as described above, the propulsion device includes a plurality of propeller devices that rotate in the air. This makes it easier to navigate the boat body in the paddy field by making it less likely to entangle rice plants and damage them than with a propeller device in the water. In addition, by providing a plurality of propeller devices, steering is possible by utilizing the thrust difference of the propeller devices in the air, even if the rudder in the water is omitted. Effect of the Invention

[0015] The methane generation reduction device of this invention can reduce the amount of methane generated by anaerobic fermentation in paddy field soil. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing the configuration of a methane generation reduction device according to an embodiment of the present invention; [Diagram 2] 1 is a perspective view of an apparatus for reducing methane emissions according to an embodiment of the present invention; [Diagram 3] 1 is a schematic diagram showing the configuration of a soil action unit and an oxygen supply unit of a methane production reduction device according to an embodiment of the present invention; [Figure 4] 2 is a perspective view showing the structure of a soil action unit and an oxygen supply unit of a methane generation reducing device according to an embodiment of the present invention; FIG. [Diagram 5] 1 is a top view of an apparatus for reducing methane emissions according to an embodiment of the present invention; FIG. [Figure 6] 4 is a map showing the oxygen concentration measured by an underwater oxygen concentration meter of the methane generation reducing device according to the embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a methane generation reducing device according to an embodiment of the present invention will be described with reference to the accompanying drawings. First, Fig. 1 is a schematic diagram showing the configuration of a methane generation reduction device according to an embodiment of the present invention. Fig. 2 is a perspective view showing a methane generation reduction device according to an embodiment of the present invention. Fig. 3 is a schematic diagram showing the configuration of a soil action unit and an oxygen supply unit of a methane generation reduction device according to an embodiment of the present invention. Fig. 4 is a perspective view showing the structure of a soil action unit and an oxygen supply unit of a methane generation reduction device according to an embodiment of the present invention. Fig. 5 is a top view of a methane generation reduction device according to an embodiment of the present invention. Fig. 6 is a map showing the oxygen concentration measured by an underwater oxygen concentration meter of a methane generation reduction device according to an embodiment of the present invention. Note that in Fig. 2, the oxygen supply unit 12 is omitted in order to clearly show the boat body 2 and the propulsion device 4 described later. In the following description of one embodiment of the present invention, the direction in which the front of the boat body faces is referred to as the forward side, the direction opposite the front of the boat body is referred to as the rear side, the right hand side when looking forward from the rear of the boat body is referred to as the right side, and similarly, the left hand side when looking forward from the rear of the boat body is referred to as the left side.

[0018] As shown in Fig. 1, a methane generation reducing device 1 according to one embodiment of the present invention reduces or inhibits methane generation from soil S in a paddy field A filled with water W. The paddy field A is a paddy field in which rice plants B are cultivated. The paddy field A is filled with water W (water is stored to a certain depth). The rice plants B represent rice plants in a state of growth after planting and before mid-season drying. It is known that oxygen in the water and soil of flooded paddy field A is quickly used up. When oxygen is lacking in soil S, the amount of carbon dioxide and organic acids in soil S increases rapidly, and the lack of oxygen causes the organic matter in the soil to shift from aerobic fermentation to anaerobic fermentation, producing methane M. For example, rice straw that has fallen in paddy field A and remnants of the previous year, such as rice stalks left after harvesting, can generate large amounts of methane M.

[0019] Generally, a method for reducing or suppressing the generation of methane M and other gases is known to be to drain the water from paddy field A for a certain period of time. By draining the water and exposing the soil to air, the reduced state of the soil is switched to an oxidized state, suppressing the generation of methane M and other gases. The researchers of this invention conducted extensive research into a device that would reduce or inhibit the methane generation from soil S in paddy field A, and discovered this invention. The methane generation reduction device 1 of the present technology has the effect of reducing or suppressing the generation of methane M, etc., and therefore can also shorten the mid-drying period. Furthermore, the methane generation reduction device 1 can reduce or suppress the generation of methane M, etc. before and after mid-drying in addition to mid-drying.

[0020] As shown in Figure 1, the methane generation reduction device 1 comprises a boat body 2 extending from bow to stern, a propulsion device 4 for propelling the boat body 2, a soil action unit 10 (chain mechanism) suspended from the boat body 2 toward the soil on the bottom of the water, an oxygen supply unit 12 (oxygen introduction unit) suspended from the boat body 2 toward the water, and a control unit 22 for controlling the unmanned navigation of the boat body 2 on the water surface.

[0021] The boat body 2 forms a boat that sails unmanned without any person on board. For example, the boat body 2 does not have enough buoyancy to carry an adult person (for example, about 70 kg). The boat body 2 forms a buoyant body that floats on the water. The boat body 2 forms a radio-controlled small vessel. The boat body 2 is formed to a size that generates buoyancy that allows the propulsion device 4 that generates the propulsive force of the boat body 2, the control unit 22, the soil action unit 10, and the oxygen supply unit 10 to be mounted on the water. The boat body 2 is formed to a size of, for example, about 0.3 m x about 0.3 m (0.09 square meters), and is formed to a size of, for example, less than .1 square meter when viewed from above.

[0022] The boat body 2 navigates over the paddy field A, which is filled with water and where rice plants B are growing. The boat body 2 has a flat bottom surface that is relatively parallel to the water surface so that it can run over the rice plant B. Since the boat body 2 has a relatively flat bottom surface, it is less likely to damage the rice plant when it runs over the rice plant, and the boat body 2 is less likely to get entangled in the rice plant or weeds. The rice plant B is in a state of growth before mid-season drying after planting, and since it bends relatively flexibly, the boat body 2 can often run over the rice plant B, which is in an environment where it often stands up again and stands on its own after being run over. Research results have been reported that rice plants that have been knocked over once grow stronger, and tillering is promoted, resulting in an increase in harvest. If the boat body 2 cannot run over the rice plant B due to its growth state, the boat body 2 can achieve a certain degree of effect of the present technology by sailing around the rice plant B.

[0023] The propulsion device 4 is provided on the boat body 2. The propulsion device 4 includes a base 6 formed to rise from the boat body 2 approximately at the center in the fore-and-aft direction of the boat body 2, and a propeller device 8 that rotates a propeller in the air above the boat body 2. The propulsion device 4 includes a plurality of propeller devices 8 that rotate in the air.

[0024] The base 6 extends vertically upward from the boat body 2. The base 6 is formed in a rectangular frame shape when viewed from the front. The base 6 is formed so as to extend to a height within a range of about 10 cm to about 20 cm from the water surface.

[0025] As shown in FIG. 2, the propeller device 8 is attached to the top of the base 6 facing forward. The propeller device 8 includes a first propeller device 8a arranged on the right side when viewed from the rear of the propulsion device 4 to the front, and a second propeller device 8b arranged on the left side when viewed from the front. The first propeller device 8a and the second propeller device 8b are arranged side by side in the width direction of the boat body 2. The propeller device 8 includes a motor 8c (see FIG. 1) whose rotation speed and rotation direction can be controlled, and the motor 8c can drive the propeller in a forward rotation and a reverse rotation opposite to the forward rotation. By freely controlling the rotation speed of the left and right motors 8c, a difference in propulsive force is generated between the first propeller device 8a and the second propeller device 8b, and the boat body 2 can be rotated and a pivot turn can be performed. For example, one motor may be driven and the other motor may be stopped. In addition, a pivot turn can be performed by rotating one of the motors in the reverse direction. Since the propulsion device 4 is installed in the air above the boat body 2, it is possible to prevent damage to the rice and also to prevent traffling, such as the rice becoming entangled in the propulsion device 4. Although the propulsion device 4 makes it possible to omit a rudder installed underwater, the boat body 2 may be provided with a rudder underwater.

[0026] The diameter of the propeller of the propeller device 8 is within a range of about 30 cm to about 50 cm. In addition, the motor 8c is configured so that the average rotation speed during normal straight-line running is within a range of about 4000 rpm to about 12000 rpm.

[0027] As shown in Figures 1, 3 and 4, the soil action part 10 extends from the boat body 2 so as to hang down into the water W towards the soil S on the bottom of the water. The soil action part 10 forms, for example, a chain mechanism (chain portion) in which hollow cylinders (cylindrical portions) are linked. The edges of the cylinders of the chain form the cylindrical portion 10b, which is the action part, and the soil S is stirred by the cylindrical portion 10b.

[0028] As shown in FIG. 1, the soil action part 10 is attached to the rear of the boat body 2. The soil action part 10 is formed to have a length that reaches at least from the boat body 2 to the soil S at the bottom of the water. For example, the length of the soil action part 10 is a length obtained by adding a predetermined length L1 (for example, 20 cm) to the height H1 from the soil S at the bottom of the water to the water surface. The length of the soil action part 10 is within a range of about 20 cm to about 40 cm. When the boat body 2 sails, the action part 10a of the predetermined length L1 of the soil action part 10 acts to stir the soil in the soil S at the bottom of the water. The predetermined length L1 is arranged almost horizontally with the soil and acts to scrape the soil. For example, the cylindrical edge part of the soil action part 10 scrapes the surface layer of the ground and stirs the water and soil near the bottom. For example, the end of the hollow metal cylinder forms a slightly pointed edge part due to the end of the metal plate. The length of the action part 10a is within a range of about 3 cm to about 30 cm. In the present embodiment as shown in Figures 3 and 4, the chain mechanism is formed by connecting hollow cylinders, but the soil action part 10 may be formed to have a chain mechanism such as a chain-like or other shaped chain. For example, in Figure 2, a chain mechanism (chain part) using a chain is formed as a modified example.

[0029] As shown in FIG. 5, a plurality of soil action units 10 are attached to the rear of the boat body 2 in a top view, lined up in the width direction of the boat body 2.

[0030] As shown in FIG. 3, the soil action part 10 includes a plurality of cylinders 10b connected by a chain mechanism. The connecting part 10c of the cylinder 10b is connected to the connecting part 10c of another cylinder, and is formed to bendable at the connecting part of the cylinder. The cylinder 10b is formed in a hollow tubular shape. The connecting part 10c connects the ends of the adjacent cylinders with a string-like flexible member, for example. Therefore, the soil action part 10 is formed to be bendable at the connecting part 10c like a snake. The soil action part 10 is hung from the boat body 2 toward the rear under the water surface. The soil action part 10 is attached from the rear part of the boat body 2 toward the rear, in a direction generally parallel to the supply part 16. The soil action part 10 is formed so that the angle can be freely changed (can be freely bent) according to the traveling direction of the boat body 2. The soil action part 10 is indicated by a dashed line in FIG. 1 in order to distinguish it from the supply part 16 described later. The chain mechanism may be formed by connecting members of other shapes instead of the cylinder 10b. That is, the soil action parts are connected by connecting parts that become nodes to form a chain mechanism. For example, the soil action parts may be formed with protrusions or claw-like parts, or may have holes. The chain mechanism may be formed of a so-called box chain (Venetian chain) having links with a square outer shape. For example, by forming the chain mechanism with a box chain, a stronger stirring action can be generated by the corners of the chain.

[0031] As shown in FIG. 1, the oxygen supply unit 12 includes an oxygen supply device 14 provided on the boat body 2, and a supply unit 16 that supplies oxygen from the oxygen supply device 14 into the water. The oxygen supply device 14 is electrically connected to a battery and a control unit provided on the boat body 2. The timing and amount of oxygen supplied by the oxygen supply device 14 are electrically controlled by the control unit. The oxygen supply device 14 may be an air pump device that supplies air (atmosphere). Oxygen can be supplied by supplying air (atmosphere) using an air pump. The oxygen supply device 14 functions as the oxygen supply unit even when air is introduced. The oxygen supply device 14 may be equipped with, for example, a high-pressure oxygen tank and supply oxygen from the tank. The oxygen supply device 14 may also be equipped with, for example, an electric oxygen generator.

[0032] The supply unit 16 of the oxygen supply unit 12 hangs from the boat body toward the rear, below the water surface. The supply unit 16 is attached from the rear of the boat body 2 toward the rear, in a direction generally parallel to the soil action unit 10. The supply unit 16 is formed so that its angle can be freely changed (it can be freely bent) according to the traveling direction of the boat body 2.

[0033] The supply unit 16 of the oxygen supply unit 12 forms, for example, an air stone tube. The supply unit 16 supplies air C in the form of bubbles into the water. The air C in the form of bubbles contains oxygen. The air stone tube has many holes formed on its outer circumference, through which oxygen (air) is supplied to the outside. The supply unit 16 is arranged so as to extend along the soil action unit 10. When the supply unit 16 is formed by an air stone tube, the air stone tube is arranged so as to extend along the soil action unit 10. The air stone tube of the supply unit 16 extends so as to pass through the cylinder 10b of the chain mechanism. The air stone tube of the supply unit 16 extends through a plurality of cylinders 10b. The air stone tube of the supply unit 16 can be easily bent to match the soil action unit 10, so it can be installed in combination with the soil action unit 10. The air stone tube is, for example, a vinyl tube, and has flexibility. In order to simplify the drawing, only the section 16a of the air stone tube with a predetermined diameter is shown in Fig. 3. As shown in Fig. 6, the air stone tube with a predetermined diameter continues in section 16b, and the end of section 16b of the supply unit 16 is connected to the oxygen supply device 14. The diameter and shape of the supply unit 16 may be changed in section 16b.

[0034] The supply unit 16 is not limited to a tube type, and may be formed by connecting a round columnar air stone to an air pipe tube. The air stone portion is difficult to bend according to the soil action unit 10, but has certain advantages such as being relatively inexpensive and unlikely to damage rice plants even if it hits them. The average pore size of the air stone portion of the supply unit 16 can be formed to be within the range of 0.01 mm to 0.03 mm, for example, approximately 0.02 (20 microns). The supply unit 16 may be configured to mainly generate air bubbles smaller than about 100 μm in diameter, for example, microbubbles with a diameter in the range of about 1 μm to 60 μm, or nanobubbles with a diameter in the range of about 1 μm to 3 μm. In this case, the supply unit 16 may be equipped with a high-pressure compressor, a microbubble supply device, or a nanobubble supply device as necessary.

[0035] In the supply part 16, for example, many air holes are formed along the entire circumference of the supply part from the section 16b at the base to the section 16a penetrating the cylinder along the length direction of the air stone tube. In the supply part 16, the air holes may be formed mainly near the section 16a on the cylinder side, for example, near the cylinder 10b (for example, a portion about 30 cm long from the tip of the supply part 16). The supply part 16 is formed to a length shorter than the soil action part 10.

[0036] As shown in FIG. 1, the methane generation reduction device 1 further includes a battery 18 that supplies electricity to each device on the boat body 2, a communication device 20 that communicates with the outside, and an operation unit 24 for controlling the control unit 22 at a location separated from the boat body 2.

[0037] The battery 18 is electrically connected to the control unit 22, the propulsion device 4, the oxygen supply unit 12, etc. The battery 18 supplies electricity to the control unit 22, the propulsion device 4, the oxygen supply unit 12, the communication device 20, etc. The communication device 20 is connected to a control unit 22 and can receive command signals from an external operation unit 24 and can transmit command signals from the control unit 22 to the operation unit 24 .

[0038] The operation unit 24 is formed by an electronic device operated by a user, for example, a controller. The operation unit 24 transmits a command signal to the communication device 20, and can move the boat body 2 forward, turn right, turn left, and move backward through the control of the propulsion device 4. The operation unit 24 may move the boat body 2 forward, turn right, turn left, and move backward through a user interface displayed on a screen of a smartphone or the like. The operation unit 24 may be configured by a program or the like provided on a server or a PC. The operation unit 24 is electrically connected to the control unit 22 and can control the control unit 22. The operation unit 24 can also control the start and stop of the supply of oxygen from the oxygen supply device 14 through the control unit 22. Note that some of the functions of the control unit 22 may be provided on the operation unit 24 side. The operation unit 24 may be omitted, and in that case, the boat body 2 may be controlled by automatic control based on the judgment of the control unit 22 itself, and oxygen may be supplied into the water.

[0039] The methane generation reducing device 1 may further include an underwater oxygen concentration meter 28 that measures the oxygen concentration in the water. The underwater oxygen concentration meter 28 has a function of measuring the oxygen concentration in the water. Since the underwater oxygen concentration meter 28 can measure the oxygen concentration in the water, it can distinguish areas of low oxygen concentration in the water. Furthermore, as shown in FIG. 6, the methane generation reduction device 1 can store and display the oxygen concentration measured by the underwater oxygen concentration meter 28 by region in the map E showing the paddy field A. For example, in FIG. 7, the region L where the oxygen concentration measured by the underwater oxygen concentration meter 28 is low is shown by a dashed dotted line). Conversely, for example, the region H where the oxygen concentration measured by the underwater oxygen concentration meter 28 is high is shown by a dashed dotted line). Therefore, the methane generation reduction device 1 can control the boat body 2 to focus on sailing through the region L where the oxygen concentration is low, thereby efficiently reducing methane generation.

[0040] The control unit 22 is disposed on the boat body 2. The control unit 22 controls the unmanned navigation of the boat body 2. Unmanned navigation means that no person is on board the boat body 2 while the boat is traveling. The control unit 22 constitutes a control unit for the navigation of the boat body 2 and also constitutes a control unit for oxygen supply by the methane generation reduction device 1. Thus, the control unit 22 has a function of reducing methane generation from the soil S of the paddy field A.

[0041] The control unit 22 is electrically connected to, for example, the propulsion device 4, the propeller device 8, the soil action unit 10, the oxygen supply unit 12, the battery 18, the communication device 20, the operation unit 24, the underwater oxygen concentration meter 28, etc., and has a function of controlling the connected devices. The control unit 22 has a built-in CPU, memory, etc., and controls the connected devices based on a predetermined control program recorded in the memory, etc. The electrical connection between the control unit 22 and other devices may be entirely or partially connected by wireless communication such as infrared communication or other methods. The control unit 22 may be electrically connected to an external control unit of the boat body 2, for example, the operation unit 24, via the Internet. A part of the control unit 22 may be located physically away from the boat body 2, or may be provided in the form of a program on a server via the Internet. For example, a part of the control unit 22 may be provided on the operation unit 24 side. The control unit 22 is not limited to a unit that receives commands from the outside and performs predetermined control, but may also navigate the boat main body 2 and supply oxygen into the water, etc., based on the judgment of its own control program. The control unit 22 has a program and function for navigation of the boat main body 2. The control unit 22 also has a program and function for supplying oxygen into the water, etc., by the oxygen supply unit 24, etc.

[0042] For example, the control unit 22 is equipped with an automatic driving function that enables the boat body 2 to automatically drive throughout almost the entire working area D of the paddy field A in which the boat body 2 is being worked, thereby carrying out work to reduce methane generation. As shown in FIG. 6, the control unit 22 stores a map E of the paddy field A to be worked on. For example, the control unit 22 can set a virtual marker N for GPS to specify the outer edge of the paddy field A (the outer edge of the working area D) on the map E. For example, four virtual markers N can be set in FIG. 6. Then, an area surrounded by the virtual markers N, for example, an area shown by a dashed line in FIG. 6, can be set as the working area D. The control unit 22 can automatically run the boat body 2 in the working area D by a predetermined method. The control unit 22 can automatically run the boat body 2 so as to run substantially evenly throughout the entire working area D. The course to run within the working area D can be determined by the judgment of the control unit 22. The course to run may be set in advance to run the entire working area D. The control unit 22 may run the boat body 2 multiple times with a focus on a portion of the paddy field A. For example, the control unit 22 may automatically run the boat body 2 so as to run multiple times through an area L with a low oxygen concentration within the working area D. Furthermore, the control unit 22 can use the automatic driving function to once have the boat body 2 travel almost entirely within the paddy field A, and then travel again for the second and third rounds, etc., so that the boat body 2 travels almost entirely within the paddy field A. In this way, after starting to travel within the paddy field A, the control unit 22 can travel within the work area D at its own discretion, without receiving commands such as its own travel course from the outside.

[0043] For example, the control unit 22 may cause the boat body 2 to travel within the paddy field A in response to a command from a user operating the operation unit 24. In this case, the boat body 2 can be operated based on external control, like a radio-controlled boat. Thus, the soil of the paddy field A can be stirred in the area where the boat body 2 travels, making it easier for the oxygen supply unit to supply oxygen to the soil.

[0044] 6, the control unit 22 stores a map E of the paddy field A to be worked on. The control unit 22 may use the map E to control the boat body 2, or may add distribution information of the underwater oxygen concentration to the map E. For example, a user operating the operation unit 24 may travel the boat body 2 intensively through a part of the area L in the paddy field A where the oxygen concentration in the water is low, while looking at information on the underwater oxygen concentration on the map E.

[0045] The control unit 22 has a methane generation reduction function that can execute a methane generation reduction operation. According to the methane generation reduction function, the control unit 22 drives the oxygen supply device 14 and causes the supply unit 16 to supply oxygen into the water. The control unit 22 executes the methane generation reduction function while the boat body 2 is traveling, and can execute a methane generation reduction operation.

[0046] According to one embodiment of the present technology configured as described above, the boat body 2 includes a propulsion device 4 for propelling the boat body 2, a control unit 22 for controlling the unmanned navigation of the boat body 2 on the water surface, a soil action unit 10 suspended from the boat body 2 toward the soil at the bottom of the water, and an oxygen supply unit 12 suspended from the boat body 2 toward the water. This allows the boat body 2 to navigate unmanned on the water surface, and the soil action unit 10 to act on the soil at the bottom of the water, for example, to stir it, while supplying oxygen by the oxygen supply unit 12. This can reduce the amount of methane generated by anaerobic fermentation in the soil of the paddy field. In addition, the boat body 2 can be autonomously navigated on the water surface, and methane generation reduction work can be efficiently performed on a relatively wide area of ​​paddy fields, without the worker having to work while walking back and forth in the mud of the paddy field. This can prevent heavy labor for the worker. In addition, by implementing the present technology, the amount of methane generated from paddy fields can be reduced, for example, without extending the mid-drying period of the paddy field.

[0047] According to one embodiment of the present technology configured in this manner, the oxygen supplying unit 12 is disposed so as to extend along the soil working unit 10. This makes it easier for the oxygen supplying unit 12 to supply oxygen to the soil in accordance with the action on the soil by the soil working unit 10, for example, stirring. This makes it possible to further reduce the amount of methane generation in the soil of the paddy field.

[0048] According to one embodiment of the present technology configured as described above, the oxygen supply unit 12 includes a flexible air stone tube. This allows the flexible air stone tube to easily follow the movement of the soil action unit 10. This allows the oxygen supply unit 12 to more easily supply oxygen to the soil.

[0049] According to one embodiment of the present technology configured in this manner, the soil action part 10 is formed so that the plurality of cylindrical parts 10b are connected in series and can be bent. This makes it easier to stir the soil that has settled at the bottom of the paddy field by the end of the cylinder, and also makes it easier for the soil action part 10 to bend along the oxygen supply part 12. Even if the boat body 2 is bent, the soil action part 10 can be easily bent along the oxygen supply part 12, making it easier for the oxygen supply part 12 to supply oxygen to the soil. This makes it possible to further reduce the amount of methane generated in the paddy field soil.

[0050] According to one embodiment of the present technology configured in this manner, the air stone tube extends so as to pass through the cylindrical portion 10b of the soil working unit 10. As a result, while the soil working unit 10 stirs the soil that has settled at the bottom of the paddy field, oxygen can be relatively efficiently introduced through the air stone tube passing through the cylindrical portion. In addition, the air stone tube is easily protected by the cylindrical portion during stirring, and the air stone tube is less likely to be damaged by rubbing against the soil, etc.

[0051] According to one embodiment of the present technology configured in this manner, a plurality of the soil action parts 10 are attached to the rear of the boat body 2 in a line in the width direction of the boat body 2, and the air stone tube is arranged so as to pass through the cylinder of the soil action part 10. In this way, by arranging a plurality of the soil action parts 10, the soil of the paddy field can be effectively stirred, and by arranging the air stone tubes together with each of the soil action parts 10, oxygen can be efficiently supplied to the soil. Therefore, the amount of methane generation in the paddy field soil can be further reduced.

[0052] According to one embodiment of the present technology configured as described above, the oxygen supply unit 12 includes an air pump device that supplies air, and oxygen is supplied by the air supplied from the air pump device. Therefore, oxygen can be easily supplied to the soil with a relatively simple configuration, and the amount of methane generation in the soil of the paddy field can be further reduced.

[0053] According to one embodiment of the present technology configured as described above, the propulsion device 4 includes a plurality of propeller devices 8 that rotate in the air. This makes it difficult for rice plants to be entangled and damaged compared to underwater propeller devices, making it easier to navigate the boat body 2 in paddy fields. Furthermore, by providing multiple propeller devices, even if the underwater rudder is omitted, steering is possible by utilizing the thrust difference between the propeller devices in the air. [Explanation of symbols]

[0054] 1: Methane emission reduction device 2: Boat body 4: Propulsion device 8: Propeller device 10: Soil action part 10b: Cylindrical part 12: Oxygen supply unit 16: Supply section

Claims

1. A methane generation reduction device that reduces methane generation from rice paddy soil, The boat body that floats on the water, A propulsion device for propelling the boat body; A control unit that controls unmanned navigation of the boat body on the water surface; A soil action part that is suspended from the boat body toward the soil on the bottom of the water; and an oxygen supply unit suspended from the boat body into the water.

2. The methane generation reducing device according to claim 1 , wherein the oxygen supply section is disposed so as to extend along the soil action section.

3. 3. The methane production reduction device of claim 2, wherein the oxygen supply portion comprises a flexible air stone tube, the air stone tube extending along the soil working portion.

4. The methane generation reducing device according to claim 3 , wherein the soil interaction portion comprises a plurality of cylindrical portions connected together, and the cylindrical portions are formed so as to be bendable at the connecting portions.

5. 5. The methane generation reducing apparatus according to claim 4, wherein the air stone tube of the oxygen supply section extends through the cylindrical section of the soil working section.

6. 6. The methane generation reduction device as described in claim 5, wherein a plurality of the soil action parts are attached in a line in the width direction of the boat body at the rear of the boat body, and the air stone tube is arranged so as to pass through the cylinder of the soil action part.

7. The methane generation reducing device according to claim 6 , wherein the oxygen supplying section includes an air pump device for supplying air, and oxygen is supplied by the air supplied from the air pump device.

8. The methane production reduction device of claim 7 , wherein the propulsion device comprises a plurality of propeller devices that rotate in air.

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