Paddy field weeder and paddy field weeding method

Abstract

We provide weeders and other equipment for removing weeds such as barnyard grass and monocotyledonous grass from rice paddies. [Solution] A paddy field weeder 101a has substantially spherical outer cases 21a, 22a, a rotation mechanism provided inside the outer cases 21a, 22a, and a plurality of annular convex portions 31a provided on the outer cases 21a, 22a. The weeder 101a can have a bridging portion that spans the recessed portion on the inside of the annular convex portion 31a. Also, a paddy field weeding method using the weeder 101a includes introducing the weeder 101a into the paddy field after rice planting and moving the weeder 101a within the paddy field to remove weeds.

Description

[Technical Field]

[0001] The present invention relates to a weeder for paddy fields and a method for weeding paddy fields. [Background technology]

[0002] Japan has many irregularly shaped rice paddies, such as terraced rice paddies and small paddies in mountainous and hilly areas. In these types of paddies, weeding with large machinery can be difficult. At the same time, there is a strong demand for organic farming, which reduces the use of chemical pesticides. However, mountainous and hilly areas where rice paddies such as terraced rice paddies and small paddies are cultivated are particularly affected by depopulation and an aging population, and some areas are experiencing serious labor shortages. In addition, weeding by hand during the hot days is inefficient.

[0003] One of the barriers to implementing organic rice cultivation is the overgrowth of weeds such as barnyard grass and Monochoria vaginalis. To address this, various technologies have been introduced, including mechanical methods such as robots, biological weed control using ducks, and cultural weed suppression. Recently, the development of autonomous weeding robots that utilize robotics and information and communication technology has progressed, and robots for paddy fields in prepared plots are now commercially available. However, there are few examples of the development of robots suitable for small-area paddy fields such as terraced rice fields.

[0004] One approach being considered is to remove weed seeds and germinated weeds from the soil in rice paddies while simultaneously stirring and muddying the soil to reduce the time available for photosynthesis and suppress weed growth.

[0005] For example, Patent Document 1 discloses a paddy field weeding robot that has left and right wheels that are independently controlled to rotate, and a main body that has a control unit that controls the rotation of at least the left and right wheels, and each of the left and right wheels is composed of a thin disk and a number of rods that are fixed at one end at predetermined intervals along the periphery of the thin disk and are parallel to the axial direction of the thin disk.

[0006] Patent Document 2 discloses a weed control device that controls weeds by floating and moving on the water surface. The device has a motor and a power supply housed in a waterproof main body case, and is equipped with wheels and a stirring wire driven by the motor. The motor rotates with electricity supplied from the power supply, and the device moves using the wheels and stirs mud on the surface of the soil using the stirring wire.

[0007] Patent Document 3 discloses a paddy field soil tillage body having an approximately spherical outer surface with a tilling section provided on the outer surface, characterized in that the tilling section is formed from a rigid body. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-053894 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-52276 [Patent Document 3] Japanese Patent Publication No. 2021-114947 Summary of the Invention [Problem to be solved by the invention]

[0009] The maintenance and utilization of rice terraces and small paddy fields requires a significant reduction in labor hours and lighter labour, and there is a particular need for the development of technology to reduce the labour required for weeding in paddy fields, which takes a long time in hot weather. Although paddy field weeding robots such as those in Patent Documents 1 and 2 have been disclosed, they are not always able to remove weeds from the appropriate direction in paddy fields, and may not be able to handle the complex shapes of rice terraces and small paddy fields.

[0010] The weed remover in Patent Document 3 is a sphere with protrusions on its outer periphery, which moves in various directions within a paddy field, digging up and stirring the soil with the protrusions, thereby removing weeds. However, as the weed remover moves and knocks over the rice plants, the protrusions hit the rice plants, causing a significant impact on the rice.

[0011] Under these circumstances, an object of the present invention is to provide a weeder and a weeding method for removing weeds in paddy fields. [Means for solving the problem]

[0012] The present inventors have conducted extensive research to solve the above problems and have found that the following inventions meet the above objectives, thereby completing the present invention.

[0013] <1> A paddy field weeder having a substantially spherical outer case, a rotation mechanism provided inside the outer case, and a plurality of annular protrusions provided on the outer case. <2> The annular projection has a bridge portion that bridges the recessed portion on the inside thereof. <1> 2. A paddy field weeder according to claim 1. <3> the bridge portion is linear or strip-shaped, one or two bridge portions are provided per one annular convex portion, and two or more openings are formed in the concave portion on the inside of the annular convex portion; The annular convex portion has a detachable portion to which a bridging member can be attached and detached. <2> 2. A paddy field weeder according to claim 1. <4> the annular protrusion is 3 mm or more higher outward than the outer circumferential surface of the outer case and has flexibility; <1> ~ <3> 10. The paddy field weeder according to claim 9, wherein the paddy field weeder is a weeder for weeding rice paddies. <5> The annular protrusion is a part of a member that can be attached to and detached from the outer case. <1> ~ <4> 10. The paddy field weeder according to claim 9, wherein the paddy field weeder is a weeder for weeding rice paddies. <6> A method for weeding rice paddies using a rice paddy weeder having a substantially spherical outer case, a rotation mechanism provided inside the outer case, and a plurality of annular protrusions provided on the outer case, wherein after rice planting, the weeder is brought into the rice paddy and moved within the rice paddy to remove weeds. [Effects of the Invention]

[0014] According to the present invention, weeds in paddy fields can be removed. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of a weeder according to a first embodiment of the present invention. FIG. [Figure 2] 1 is an image of a manufacturing example of a weeder of the present invention. [Figure 3] 1 is an enlarged image of a manufacturing example of an annular convex portion of a weeder according to the present invention. [Figure 4] 1 is a perspective outline view of a member for an annular convex portion that can be used in the weeder of the present invention. FIG. [Figure 5] FIG. 1 is a schematic front view of a member for an annular convex portion that can be used in the weeder of the present invention. [Figure 6] 1 is an image of a manufacturing example of a member for an annular convex portion that can be used in the weeder of the present invention. [Figure 7] 1 is an image showing a manufacturing example of a bridge portion that can be attached to the annular convex portion of the present invention. [Figure 8] 1 is an image showing an example of a rotation mechanism of a weeder of the present invention. [Figure 9] 10 is an image of a weeder according to a second embodiment of the present invention. [Figure 10] 10 is an image of a weeder according to a third embodiment of the present invention. [Figure 11] 10 is an image of a weeder according to a fourth embodiment of the present invention. [Figure 12] 1 is an image showing an example of a state in which the weeder of the present invention is used in a paddy field. [Figure 13] FIG. 1 is a schematic diagram for explaining a test schedule of an example. [Figure 14] 1 is a graph illustrating test results of examples. DETAILED DESCRIPTION OF THE INVENTION

[0016] The following describes in detail an embodiment of the present invention, but the following description of the constituent elements is one example (typical example) of an embodiment of the present invention, and the present invention is not limited to the following content unless the gist of the present invention is changed. Note that when the expression "to" is used in this specification, it is used as an expression that includes the numerical values before and after it.

[0017] [Weeder of the present invention] The weeder of the present invention is a weeder for paddy fields having a substantially spherical outer case, a rotation mechanism provided inside the outer case, and a plurality of annular protrusions provided on the outer case.

[0018] [Weeding method of the present invention] The weeding method of the present invention is a method for weeding rice paddies using a rice paddy weeder having a substantially spherical outer case, a rotating mechanism provided inside the outer case, and a plurality of annular protrusions provided on the outer case, in which the weeding method involves bringing the weeding machine into the rice paddy after rice planting and moving the weeding machine within the rice paddy to remove weeds.

[0019] In the present application, the weeding method of the present invention can also be carried out using the weeder of the present invention, and the corresponding configurations in the present application can be used mutually.

[0020] [First embodiment] Fig. 1 is a schematic diagram of a weeder according to a first embodiment of the present invention. Fig. 2 is an image of a manufacturing example of a weeder similar to the weeder of Fig. 1. Fig. 3 is an enlarged image of the annular convex portion of the weeder of the present invention.

[0021] As shown in FIG. 1, a weeder 101a has an outer case 21a, an outer case 22a, and a plurality of annular protrusions 31a. FIG. 2 is an image of a manufacturing example of a weeder 101 similar to the weeder 101a of FIG. 1. The weeder 101 has an outer case 21, an outer case 22, and a plurality of annular protrusions 31. FIG. 3 is an enlarged image of the annular protrusions 31 of the weeder 101a. The annular protrusions 31 have a protrusion 311 and a recess 312. A bridging portion 313 can be provided on the annular protrusions 31 so as to span the annular protrusions 31.

[0022] [Weeding machine] The weeder is spherical. It has an internal rotating mechanism, and when placed in a rice paddy and rotated, it stirs up the surface of the soil, pulling out and removing weeds such as barnyard grass and Monochoria vaginalis immediately after germination. Because the weeder is spherical, it can move in various directions, allowing it to weed in a way that suits the shape of even rice paddies with complex shapes, such as terraced rice paddies and small rice paddies. It is also easy to handle and can be easily switched between applications in rice paddies, making it possible to adjust the appropriate weeding time and frequency to maximize the weed-killing effect depending on the type of weed.

[0023] [External case] The outer case is the basic shape of the weeder, which is a spherical body, and is a case that houses the internal rotation mechanism. The outer case may have portions with projections and recesses related to the annular projection, but is generally spherical overall.

[0024] The external case may further include a housing case for the inner rotation mechanism, or the housing case for the rotation mechanism may also serve as the external case. The weeder has an annular convex portion on the outer surface of the external case. The external case may be formed as an integral unit with the annular convex portion disposed from the beginning (see Figures 6 and 8). Alternatively, the external case may have a detachable mounting portion for mounting a member for forming the annular convex portion (see Figures 1 to 3, etc.). Alternatively, the external case may be a substantially spherical body that is attached using a mounting member for attaching the annular convex portion.

[0025] The outer case can be a molded body made of any material such as various resins. Preferably, the outer case is made of a flexible material, which can serve as a protective cover for the weeder and reduce the burden on the rice plants when weeding.

[0026] The outer case can be appropriately designed taking into consideration the usage environment, total weight, etc., and can be, for example, about 20 cm to 50 cm in diameter, or about 25 cm to 35 cm in diameter. If it is too small, it may be difficult to reach the roots of weeds, resulting in insufficient weed-killing effect or taking a long time to kill weeds. If it is too large, it may cause a heavy burden on the rice plants or be difficult to handle.

[0027] [Annular convex part] The weeder has an annular convex portion. The annular convex portion is higher outward than the spherical surface of the outer case, and has a concave center, giving it a caldera-like shape. This annular convex portion allows the weed puller to scrape out weed seeds and germinated weeds from the soil as it moves through the rice paddy. The annular convex portion also increases the contact area with the rice paddy soil as it moves, and water flows into the central concave portion, resulting in an excellent agitation effect. This prevents excessive concentration of force in one area, such as a mountain-shaped protrusion, and increases the contact area and frequency with the soil while minimizing damage to the rice plants, allowing for efficient weed removal of weeds with poor rooting.

[0028] The annular convex portion can be a molded body made of any material, such as various resins. The annular convex portion is preferably made of a flexible material. The annular convex portion frequently comes into contact with rice plants, but using a flexible material can reduce the burden on the rice plants during weeding. As a flexible material, so-called rubber-like resins can be used. For example, thermoplastic elastomers can be used, and a more specific example is polyurethane-based thermoplastic elastomers (TPU).

[0029] A plurality of annular protrusions are provided on the outer case. The number of annular protrusions is appropriately designed depending on the sizes of the weed cutter and the outer case, the sizes of the annular protrusions, etc. The number of annular protrusions can be, for example, 6 or more, 8 or more, 10 or more, 15 or more, etc. There is no particular upper limit to the number of annular protrusions, but an upper limit of 50 or less, 40 or less, 30 or less, etc. may be set in consideration of limitations on available placement locations, moldability, etc.

[0030] The positions where the annular protrusions are provided are designed as appropriate depending on the size of the outer case, the size of the annular protrusions, etc. They can be provided evenly around the outer case so that they can come into contact with the soil from various directions and remove weeds when moving through the paddy field, and may be provided at positions corresponding to the vertices of a regular polygon, arranged in line symmetry or point symmetry, arranged periodically on multiple meridians of a sphere, or arranged irregularly.

[0031] The size of the annular convex portion can be about 3 cm to 7 cm, or about 4 cm to 6 cm in diameter, which is the longest distance between both ends of the convex portion. The height and width of the convex portion can be about 3 mm to 15 mm, or about 8 mm to 12 mm. The recessed hole in the center of the annular convex portion can have a diameter of about 2.0 cm to 5.0 cm, or about 2.5 cm to 4.0 cm, and a depth of about 0.5 cm to 2.0 cm, or about 0.8 cm to 1.5 cm, depending on the shape of the annular convex portion.

[0032] [Annular convex part] Depending on the shape of the outer case, the annular protrusion may be a detachable annular protrusion member. Such a detachable shape makes it easy to adjust the placement frequency of the annular protrusions, change the shape of the annular protrusions during use, and perform maintenance on the annular recesses, etc.

[0033] The method for attaching and detaching the annular convex portion member can be adjusted as appropriate depending on the shape of the outer case, etc., but it may be one that screws onto the outer case, one that can be fitted together, or one that is fixed with a fixing tool (see Figure 10).

[0034] [Bridge part] The bridging portion is a portion that bridges the recessed portion inside the annular convex portion. It is preferable that the annular convex portion is provided with a bridging portion. The bridging portion may be provided on all or some of the annular convex portions of the weeder. By providing a bridging portion, the scraping force and agitation properties during rotation can be changed, so that the weeding ability can be adjusted according to the condition of the paddy field, the type of weed, the properties of the soil, the growth stage, etc.

[0035] When a bridging section is provided, the recessed portion inside the annular convex portion is separated at the top, which is thought to function as follows: When rotating, this separated portion becomes an opening-like portion that functions as an inlet and outlet side for soil, water, muddy water, etc., using the recessed portion as a flow path. The simple flow path-like portion of the inlet and outlet opening structure formed by the recessed portion and bridging section becomes an area where the flow differs from the surrounding area when the weeder rotates. This flow scrapes out soil and stirs muddy water, making it easier for weeds to float up. Furthermore, when weeds get in between the recessed portion and the bridging section, they can be caught and removed.

[0036] The bridging portion may have any shape that can span the annular convex portion, and for example, a linear, rod-like, or strip-like shape can be used. One or more bridging portions may be provided on one annular convex portion. When two or more bridging portions are provided, the bridging portions may intersect with each other in a cross shape, or may be parallel or V-shaped and not intersect with each other.

[0037] The bridge portion can be made detachable by providing a detachable portion on the annular convex portion, like attachment portion 339 (see FIG. 6). By making it detachable, it becomes easier to set the presence or absence of the bridge portion and the state of the bridge to any state.

[0038] The cross-linked portion is preferably flexible. Depending on the shape of the cross-linked portion, the cross-linked portion may have a shape that protrudes outward from the annular convex portion. This makes it easier for the cross-linked portion to come into contact with the rice plants, but in order to reduce the burden on the rice plants when the cross-linked portion comes into contact with the rice plants, the cross-linked portion is preferably formed from a flexible material.

[0039] Fig. 4 is a schematic perspective view of a member for an annular convex portion that can be used in the weeder of the present invention. Fig. 5 is a schematic front view of a member for an annular convex portion that can be used in the weeder of the present invention. Fig. 6 is a schematic view of a member for an annular convex portion that can be used in the weeder of the present invention.

[0040] 4(a) is attached with bridging portions 3231a and 3232a. The annular convex portion member 32a is attached to the outer case by the detachable portion 324a to form an annular convex portion. The annular convex portion member 32a has a convex portion 321a that becomes convex in the weeder and a concave portion 322a.

[0041] The annular convex portion member 33a in Fig. 4(b) has a bridging portion 333a attached. The annular convex portion member 33a is attached to the outer case by a detachable portion 334a to form an annular convex portion. The annular convex portion member 33a has a convex portion 331a that becomes convex in the weeder and a concave portion 332a.

[0042] FIG. 5(a) is a front view of the annular convex portion member 33a in FIG. 4(b). FIG. 5(b) is a cross-sectional view of the annular convex portion member 33a. When the convex portion 331a of the annular convex portion member 33a is attached to the external case, the upper detachable portion 3341a of the detachable portion 334a is aligned with the spherical surface of the external case. The height h1 between the upper detachable portion 3341a and the convex portion 331a is the height of the annular convex portion. The annular convex portion member 33a is attached to a bridging portion 333a. As shown in FIG. 5(b), the recess 332 can be considered to be separated by the bridging portion 333a. When rotated in a rice paddy, muddy water and soil flow from the recess 3321a side into the recess 332a and out the recess 3322a side. This flow is expected to remove weeds by increasing the water flow and stirring force, or by scraping off the weeds with the bridge portion 333a.

[0043] Figure 6 shows an example of manufacturing an annular convex member. Figure 6(a) is similar to annular convex member 32a, and has a convex portion 321, a recessed portion 322, a bridging portion 3231, a bridging portion 3232, and a detachable portion 324. Figure 6(b) is similar to annular convex member 33a, and has a convex portion 333, a recessed portion 332, a bridging portion 333, and a detachable portion 334. An annular convex member 33 is provided with an attachment portion 339 to which a bridging member can be attached.

[0044] [Bridge section components] Fig. 7 is a schematic diagram showing an example of a bridging part that can be attached to the annular convex part of the present invention. The bridging part can have a shape such as that shown in Fig. 7. Both ends of these are parts that are fitted into the attachment parts of the annular convex part for attachment, and the central part becomes the bridging part in the weeder.

[0045] [Rotation mechanism] The weeder has a rotation mechanism inside. Figure 8 is an image showing an example of the rotation mechanism of the weeder of the present invention. Figure 8 shows an internal structure 81 provided inside the weeder 101, in which a rotation mechanism 83 is arranged inside hemispherical cases 821 and 822 fixed by fixing parts 823.

[0046] This rotation mechanism is a mechanism that can move a rotating body in various directions. This mechanism has a control unit, a drive unit, a power source, etc., and can also have sensors as appropriate. The rotation direction can be forward rotation, reverse rotation, rotation around a vertical axis, etc. For example, a commercially available spherical robot such as a wireless charging type can be used. In addition, an internal rotation mechanism such as that disclosed in Japanese Patent Application Laid-Open No. 2021-114947 can also be used. Furthermore, this structure can be similar to that of the commercially available "Sphero (trademark) BOLT," for example.

[0047] The weeder is roughly spherical in shape due to the shape of the outer case, and can move in various directions. This mobility is used to weed rice paddies under various conditions while knocking down rice plants. This movement also makes it possible to weed between rice plants.

[0048] [Example of using a weeder] Weeders weigh approximately 2 kg to 10 kg or approximately 3 kg to 6 kg, depending on the size, purpose, and design. This allows for easy transport and installation. Depending on the condition of the paddy field, weeders can be designed to move in water approximately 5 cm to 12 cm or approximately 6 cm to 10 cm deep, so that they are close to the soil. It is preferable that the weeder be waterproof, with the structure of the external case and internal housing case making the rotating mechanism less susceptible to water. Furthermore, this waterproof design may be airtight, and buoyancy may be adjusted; if the weeder floats too much, weights may be added or the weight of the components may be adjusted. The weeder's travel speed may be approximately 20 cm / s to 2 m / s or approximately 30 cm / s to 1.2 m / s.

[0049] The weeder has a built-in battery to power the rotation mechanism, and the operation time can be adjusted depending on the specifications of this battery, the size of the rice paddy to be weeded, the weeding season, etc. In addition, it may be equipped with a function to automatically return home or emit a warning signal when it detects a drop in battery voltage.

[0050] The weeder may be designed to operate automatically according to the shape of the paddy field by memorizing or inputting the shape of the paddy field, or it may be designed to be moved by an operator using a remote controller. The rotation mechanism may include a control unit, a communication unit, a memory unit, etc. for such operational control.

[0051] [Second embodiment] 9 is a schematic diagram of a weeder according to a second embodiment of the present invention. Weeder 102 has an annular convex portion 41 integrally molded with an outer case, and annular convex portion 41 is shaped to allow a vinyl rope to be fixed thereto, with the vinyl rope attached as a bridging portion. The internal structure of the rotation mechanism and other components of weeder 102 can be similar to that of weeder 101.

[0052] [Third embodiment] FIG. 10 is a schematic diagram of a weeder according to a third embodiment of the present invention. The weeder 103 is configured to use a structure equivalent to the storage case of the rotation mechanism of the weeder 101 as an external case. The fixing member 61 has holes for attaching the annular convex portion member 51. The fixing member 61 is a rubber band-like member that forms a ring that matches the size of the storage case. By attaching the fixing member 61 to the storage case and attaching the annular convex portion member 51 to the holes in the fixing member 61, it is possible to create a configuration in which an annular convex portion is provided on the storage case that serves as the external case. Using such a fixing member 61 has advantages such as a lightweight external case, ease of molding, and ease of attachment and detachment.

[0053] [Fourth embodiment] 11 is a schematic diagram of a weeder according to a fourth embodiment of the present invention. As shown in weeder 104, the bridge portion and the structure for providing the bridge portion may be omitted as appropriate, and an annular convex portion 71 may be provided.

[0054] [Weeding method] The weeding method for paddy fields using a weeder can be used after rice seedlings have been transplanted into the paddy field, i.e., after rice planting. The best time to perform weeding is after the rice has taken root, for example, three days after transplanting the seedlings. In particular, weeding effectiveness can be improved by using the weeder on a schedule set according to the type of weed between one and four weeks after transplanting the seedlings. Figure 12 is an image showing the weeder of the present invention placed in a paddy field.

[0055] Weeds targeted for weed control include various weeds that grow in rice paddies, such as Monochoria vaginalis and Barnyardgrass. These are wild and tend to grow naturally even after flooding. Rice seedlings are grown for a certain period of time before being planted in paddy fields that are suitable for rice. Because rice seedlings are larger than weeds when they are first transplanted into paddy fields, weeds are well-rooted and larger from the beginning than naturally-occurring weeds. When weeds are first transplanted into paddy fields, scraping or stirring the soil and muddy water with a weeder selectively lifts small, weakly rooted weeds. These weeds are then removed by moving or replacing the water in the paddy. While the weeder moves in a manner that tramples on the rice plants, its circular convexity limits its impact on the rice plants, which can withstand the contact with the weeder and return to their normal growth state within a short period of time after weeding.

[0056] The weeding time depends on the size of the paddy field, but for example, 2 (1a) is the standard area, and you can continue driving until the battery runs low. 2 (1a) In the above, the travel area may be divided using a beacon, and weeding may be performed in each area, and after a certain period of weeding has been completed, the robot may move to another area. [Example]

[0057] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not changed.

[0058] 1. Design of a weeder (spherical robot) A test was conducted in a paddy field using a weeder similar in shape to the weeder shown in Figure 11. The weeder used consisted of an outer case and a ring-shaped protrusion (caldera section) molded as a single unit using PLA resin. The weeder used employed an autonomous mobile rotation mechanism based on the internal rotation mechanism disclosed in JP 2021-114947 A. The weeder used in the test weighed approximately 5 kg and was approximately 30 cm in diameter. The ring-shaped protrusion was approximately 5 cm in diameter, with a step of approximately 1 cm between it and the outer case. 24 ring-shaped protrusions were evenly and irregularly arranged.

[0059] 2. Materials and Methods The test will be conducted from June to August 2024 in a rice paddy (300m 2 The experiment was conducted in the Aigamo area (110m) where Aigamo ducks were released throughout the day in the paddy field. 2 ) and a robot area (70m) where a spherical robotic weeder was in operation. 2 On June 4th, 24-day-old potted seedlings (Nikomaru variety: 4-5 leaf stages, approximately 25cm tall) were transplanted at 30cm x 30cm intervals, with 3-5 plants per plant, and the water depth was maintained at 7-11cm. Seven days after transplanting (June 11th), three 7-day-old male Aigamo ducklings (Satsuma black ducks) were released into the Aigamo area, surrounded by a 100cm-high net fence (Figure 13).

[0060] In the Aigamo area, there is about 1m 2 A covered resting area was provided, and ducks were fed 30-240g of water-based pellet feed per bird per day in accordance with their growth. Meanwhile, in the robotic area, two spherical robotic weeders with a diameter of 25cm were operated for 9 hours each between days 7-20 (June 11-24) and days 43-57 (July 17-31) after rice planting (hereinafter referred to as treatments 1 and 2) (Figure 13). Figure 13 is a schematic diagram illustrating the test schedule of this example.

[0061] In the first and second treatments, the turbidity of the water on the paddy field was evaluated using a magnetic transparency meter (Kansai Kako Co., Ltd.) immediately after the operation of the spherical robotic weeder had finished. Nets were also placed at the drainage outlets of each plot, and weeds remaining there were periodically collected and then classified into barnyard grass, Monochoria vaginalis, and others, and the number of weeds was counted. Three protective cages (1.2m x 1.2m) were set up in each plot, which the ducklings and the spherical robotic weeder could not enter, and 0.5m x 0.5m quadrats (0.25m) were placed inside (untreated) and outside (treated) on the 22nd day (6 / 26) and 78th day (8 / 21) after transplanting. 2 ) was used to remove all weeds within the boxes in three locations in each plot, classifying them into barnyard grass, Monochoria vaginalis, and others, and counting the number of weeds. At the end of the experiment (August 21st), 100 rice plants that had been selected in advance in each plot were investigated to see if any plants were missing. Statistical analysis of the results was performed by comparing the transparency and the number of weeds collected at the drainage outlet between the Aigamo and robot plots, and the number of Monochoria vaginalis plants inside and outside the protective cage in each plot using a U-test.

[0062] 3. Results and Discussion The paddy fields tested showed abundant germination of Monochoria vaginalis. In the first treatment, the spherical robotic weeder operated smoothly within the paddy field, stirring up the soil surface and causing the water to become muddy. Figure 11 shows the transparency of the water immediately after the spherical robotic weeder stopped operating. The transparency in the robotic area was 6.9 cm (n9), significantly lower than the duck area's 21.1 cm (n9) (P<0.01). However, in the second treatment, the rice growth hindered the operation of the spherical robotic weeder, causing almost no water to become muddy, and the transparency was significantly higher than in the duck area (P<0.01).

[0063] The amount of weeds collected at the drainage outlet during the operation period of the spherical robot-shaped weeder is shown in Table 1 (weeds collected at the drainage outlet during the operation period of the spherical robot). In the first treatment, the water in the rice paddy became cloudy and many Monochoria vaginalis were observed floating to the surface. On the morning of the 12th June, seven days after rice planting (11th June), when the spherical robot-shaped weeder was first operated, 5,307 Monochoria vaginalis were collected (414 in the Aigamo area).

[0064] In the first treatment, an average of 165 Monochoria vaginalis, 2 Echinochloa spp., and 7 other weeds were collected in the duck area, while 1110, 3, and 8 were found in the robot area, respectively. There was a tendency for the number of Monochoria vaginalis to be higher in the robot area than in the duck area (P<0.1). In the second treatment, the number of weeds collected in both the duck and robot areas decreased compared to the first treatment, and no significant difference was observed between the two areas.

[0065] In the robot section, the spherical robotic weeder was observed knocking down the rice plants during the first treatment. However, the rice plants were observed to be standing up the day after treatment, and no missing stalks were found in the investigation conducted at the end of the test (August 21st).

[0066] Figure 14 is a graph for explaining the test results of the example. In Figure 14, a, b: P<0.01 (t-test). Also, the lower the transparency value, the greater the degree of turbidity.

[0067] [Table 1]

[0068] The number of weeds that appeared inside and outside the protective cage in each area is shown in Table 2 (Effect of spherical robot operation on weed emergence). In the test paddy fields, there was little emergence of barnyard grass throughout the test period. As for Monochoria vaginalis, there were 184 weeds / 0.25m inside the protective cage in the Aigamo duck area on the 22nd day after rice planting (6 / 26). 2 , 78 strands / 0.25m on the outside 2However, this decreased after the release of Aigamo ducks (P<0.05).

[0069] In the robot area, the inside (270 pieces / 0.25m 2 ) compared to the outer (8 pieces / 0.25m 2 ) significantly reduced the occurrence of Monochoria vaginalis, and the weeding effect of the spherical robotic weeder was significant (P<0.05).

[0070] In the duck plot, as the ducks grew older, the water in the paddy field became more turbid and weeds began to float up. On the 78th day after planting (August 21st), there were significantly fewer weeds outside the protective cage than inside (P<0.05), demonstrating a significant weed-killing effect. In the robot plot, almost no weed-killing effect was observed after the second treatment (Figure 14 and Table 1), but the number of weeds outside was significantly lower than inside (P<0.05), suggesting that the weed-killing effect from the first treatment continued.

[0071] [Table 2]

[0072] Comparison with ducklings showed that the weed-killing effect of the spherical robotic weeder was particularly pronounced in the early stages of rice growth (1-2 weeks after transplanting). [Industrial Applicability]

[0073] The present invention can be used for weed control in rice paddies such as terraced rice paddies and small rice paddies, and is therefore industrially useful. [Explanation of symbols]

[0074] 101a, 101, 102, 103, 104 Weeding machine 21a, 22a, 21, 22 outer case 31a, 31, 41, 51, 71 Annular convex part 32a, 33a, 32, 33 Annular protrusion members 311a, 321a, 311, 321 convex parts 312a, 322a, 332a, 312, 322, 332 recesses 313a, 3231a, 3232a, 331a, 313, 3231, 3232, 331 Crosslinked part 324a, 334a, 324, 334 Detachable parts 339a, 339 mounting part 61 Fixtures 81 Internal parts 821, 822 Storage Case 823 Fixed part 83 Rotation mechanism

Claims

1. a substantially spherical outer case; a rotation mechanism provided inside the outer case; a plurality of annular protrusions provided on the outer case; Paddy field weeder.

2. 2. The weeder for paddy fields according to claim 1, further comprising a bridging portion that bridges the recessed portion on the inside of the annular protrusion.

3. the bridge portion is linear or strip-shaped, one or two bridge portions are provided per one annular convex portion, and two or more openings are formed in the concave portion on the inside of the annular convex portion; 3. The weeder for paddy fields according to claim 2, wherein the annular convex portion has a detachable portion to which a bridging member can be attached and detached.

4. 3. The paddy field weeder according to claim 1, wherein the annular convex portion is outwardly higher than the outer peripheral surface of the outer case by 3 mm or more and has flexibility.

5. 5. A paddy field weeder according to claim 4, wherein the annular projection is a part of a member that can be attached to and detached from the outer case.

6. A method for weeding rice paddies using a rice paddy weeder having a substantially spherical outer case, a rotation mechanism provided inside the outer case, and a plurality of annular protrusions provided on the outer case, comprising: A method for weeding a paddy field, comprising: after rice planting, introducing the weeder into the paddy field and moving the weeder within the paddy field to remove weeds.

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