JP2003111526A - Paddy field water level-adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paddy field water level-adjusting device which can adjust a paddy field water level in a scope of about 1 m ranging from 20-30 cm on the surface of the paddy field to 70-80 cm under the ground. SOLUTION: This paddy field water level-adjusting device is characterized by comprising an intake pipe 11 whose one end is, under the ground, connected to an under drainage pipe 2 which is laid in the underground of a paddy field 1 and drains irrigation water supplied to the paddy field to a drainage channel 3, and whose downstream side end portion is opened or closed with a sluice 4, a reverse T-shaped joint pipe 6 whose lateral pipe 7 has a vertical cylinder 8 having an upper end placed on the ground surface of the paddy field and through the closed one end portion 7a of whose lateral pipe 7 the other end of the intake pipe 11 is penetrated, an upward pipe 12 which is connected to the other end of the intake pipe 11 in the joint pipe 6, has a smaller diameter than the diameter of the vertical pipe 8 of the joint pipe 6, and is upward elongated in the vertical pipe 8 and whose opened upper end is finished in the midway of the vertical pipe 8, a vertically movable water level-adjusting pipe 13 attached to the upper end of the upward elongated pipe 12, and an operation device 9 which vertically moves the inner water level-adjusting pipe 13 from the upper end of the vertical pipe 8 to adjust the upper end position of the water level-adjusting pipe 13 to a set paddy field water level, and further by connecting the other end 7b of the lateral pipe 7 of the joint pipe 6 to the drainage channel 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paddy field for rice cultivation and a water level adjusting device in a rice field for cultivating various vegetables and flowers by making paddy fields fallow.

[0002]

2. Description of the Related Art In the soil of paddy fields where rice is grown, an underdrain pipe is laid to drain groundwater that has permeated underground into the irrigation water supplied to the rice fields into drainage channels such as U-shaped grooves along the ridges. There is a lock bar at the downstream end of the underdrain pipe to open and close the underdrain pipe. As is well known, Suikan has the structures described in JP-B-60-11942 and JP-A-7-133608 proposed by the present applicant.
Vertical operation of the operation rod vertically descending from the ridge, and the plug provided at the lower end of the operation rod is lowered to close the underdrain pipe, or the plug is pulled up to open the underdrain pipe. Gazette) or a horizontal type in which a plug provided at the downstream end of the underdrain pipe opened to the drainage channel is operated from the inside of the drainage channel to close or open the downstream end of the underdrain pipe (JP-A-7-303272). Gazette).

At the time of planting or growing rice seedlings, the underdrain is closed with a barrel, and the water level of the irrigation water supplied to the rice fields is kept at about 10 cm above the rice field (ground surface of the rice fields), and the rice seedlings are kept. After growing, open the locks, discharge the irrigation water above the paddy field and its groundwater from the underdrain to the drainage channel, dry the paddy field and cut the grown rice.

In order to improve yields by cultivating vegetables and flowers (collectively referred to as plants) in paddy fields that have been made into fallow fields, it is necessary to adapt the water level in the paddy field to the roots of the plants to be cultivated. . In other words, the root water level is deepened for root vegetables and the like, and the root water level is shallow for leaf vegetables such as leaf vegetables, which are different from the plants cultivated until then. In order to cultivate these plants, it is necessary to change the water level in the ground to a level adapted to the depth of roots that the new plants drop into the ground. Also, when growing rice, the water level should be 2 above the rice field.
It is necessary to change the water level by raising it to about 0 cm and submersing the seedlings to protect it from frost, or by lowering the water level in the rice field below the root to promote root development and improve yields, such as mid-drying. There is.

[0005]

The level adjustment of the water level maintained in the rice field described above is performed by adjusting the opening of the underdrain pipe with the above-mentioned lock bar to change the amount of water discharged from the underdrain pipe to the drainage channel. It can be carried out. However, it is impossible to know what the actual water level in the rice field is, even if the opening of the barn is adjusted, and the flow rate of water flowing in the underdrain fluctuates. The level of the water level also changes according to the fluctuation, and the plant under cultivation is killed by being rooted due to overhumidity or dying due to lack of water, resulting in a situation where the harvest amount is less than the desired amount. In addition, deep water of rice seedlings,
It is not possible to keep the level of water in the mid-dried, especially in the mid-dried, accurate.

[0006]

The present invention was developed to solve the above-mentioned problems. Claim 1 is laid underground in a rice field and the irrigation water supplied to the rice field is discharged to a drainage channel. In a water level control device in a rice field where the downstream end of the drainage is attached to an underdrain pipe that is opened and closed by a barn, a water intake pipe with one end connected underground in the middle of the above-mentioned underdrain pipe and a vertical position with the upper end located on the surface of the rice field. A tube provided in the middle of the horizontal tube, and the other end of the water intake tube is embedded in the ground such that the other end of the water intake tube penetrates through the closed one end of the horizontal tube and projects into the inside, and the inside of the joint tube Connected to the other end of the intake pipe with a diameter smaller than the vertical pipe of the joint pipe, rise inside the vertical pipe, and attach it to the upper pipe of the upward pipe where the open upper end ends in the middle of the vertical pipe Vertically adjustable water level control pipe and the water level control pipe inside from the upper end of the vertical cylinder. Move the vertical direction, comprising an operating device and for adjusting the position of the upper end of the water level control pipe to the water level set level of rice field, characterized in that connected to the other end of the horizontal tube of the joint tube to the drainage channel. Further, claim 2 is a water level adjusting device in a rice field, which is laid underground in a rice field and has a downstream end for draining irrigation water supplied to the rice field to a drainage channel, which is attached to a underdrain pipe opened and closed by a barb. Is equipped with a vertical tube located on the surface of the rice field in the middle of the horizontal tube, and one end of the horizontal tube is an inverted T-shaped joint tube embedded underground in the middle of the underdrain pipe, An upward pipe that has a smaller diameter than the vertical pipe of the joint pipe, rises inside the vertical pipe, and has an open upper end that ends in the middle of the vertical pipe, and a vertically movable water level adjustment pipe attached to the upper end of the upward pipe. And an operating device for vertically moving the internal water level adjusting pipe from the upper end of the vertical pipe to adjust the position of the upper end of the water level adjusting pipe to the water level setting level of the rice field, and the lower end of the upward pipe to the joint pipe. Connected to the drain with a connecting pipe that penetrates the closed other end of the And butterflies. Further, in both the apparatus of claim 1 and claim 2, even if the water level adjusting pipe attached to the upper end of the upward pipe is a bellows that can be expanded and contracted in a vertical direction in a bellows type, it can be moved up and down in the upward pipe. It may be a fitted slide tube. In addition, the operating device that adjusts the position of the upper end of the water level adjusting pipe to the water level setting level in the rice field, stands vertically with the lower end fixed to the center of the radial connecting plate provided at the upper end of the water level adjusting pipe. An operation rod protruding upward from the upper end of the cylinder, a fixing plate radially fixed above the inside of the vertical cylinder, the fixing plate through which the operation rod penetrates the central portion, and fixed on the fixing plate, and the hollow portion is operated by the above-mentioned operation. A male screw cylinder through which the rod penetrates, a cap nut that is screwed onto the male screw cylinder from above and engaged with the screw, and located inside the cap nut. Even if it consists of an O-ring that is fixedly fastened from, the lid that opens and closes the upper end of the vertical cylinder, and the male screw cylinder that is fixed on the center of the radial connecting plate provided on the upper end of the water level adjusting pipe, Removably attached to the bottom of the lid Attached and lowered, operating rod penetrating the hollow part of the male screw cylinder and the connecting plate, a cap nut threadedly engaged with the male screw cylinder from above, and located inside the cap nut. It may be composed of an O-ring that is pressed against the operation rod by screwing it in and fixedly tightens the operation rod from the periphery. In this case, it is preferable that the outer surface of the operating rod be provided with a scale indicating the water level.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In each of the embodiments shown in the drawings, 2 is a culvert which is laid underground in a rice field 1 and drains water that has penetrated into the ground and flowed into a pipe to a drainage channel 3 provided along a ridge 5. Showing a pipe, 4 is a lock bar that opens and closes the downstream end of the underdrain pipe,
Although the vertical type described above is shown in the drawing, of course, it may be a horizontal type.

FIG. 1 shows an embodiment of a groundwater level adjusting device in a rice field according to claim 1, and FIG. 2 shows an embodiment of claim 2, which are commonly used in both embodiments and are buried in the ground. The inverted T-shaped joint cylinder 6 includes a horizontal cylinder 7 with both ends closed, and a vertical cylinder 8 that extends vertically upward from the middle of the horizontal cylinder 7 and has its upper end exposed on the ground surface of the rice field or on the ridge 5. It has, for example, a steel pipe or a vinyl chloride pipe joined in a T shape.

In the embodiment of claim 1, one end is connected underground in the middle of the underground conduit 2 and the other end is a horizontal pipe 7 of the joint pipe.
Intake pipe 1 that penetrates through the closed one end 7a and projects into the inside
1, and the diameter is smaller than that of the vertical cylinder 8 of the joint cylinder, the inside of the horizontal cylinder of the joint cylinder is connected to the other end of the water intake pipe 11 to rise inside the vertical cylinder, and the open upper end is the inside of the vertical cylinder. The upward pipe 12 that ends halfway, the vertically movable water level adjustment pipe 13 attached to the upper end of the upward pipe, and the water level adjustment pipe inside the vertical cylinder are moved vertically to move the upper end position of the water level adjustment pipe. An operating device 9 for adjusting the water level setting level of the rice field is provided, and the connecting pipe 14 connects the closed other end of the horizontal tube of the joint tube to the drainage channel 3.

The water intake pipe 11 and the upward pipe 12 may be L-shaped integral pipes, or separate pipes connected to each other by a right-angle elbow inside the horizontal cylinder 7 and below the vertical cylinder 8.

The water that flows upward from the water intake pipe 11 into the upward pipe 12 and the water level adjusting pipe 13 overflows from the upper end of the water level adjusting pipe 13 to the outer periphery of the pipe 13 and the upward pipe 12, and the vertical pipe 8. It flows down in a tubular space 15 formed between the inner circumference and the inner space, and is drained to the drainage channel 3 by a connecting pipe 14 connected to the other end of the horizontal tube.

The water flowing in the underdrain pipe closed by the water bar in this way is used as an intake pipe 11, an upward pipe 12, and a water level adjusting pipe 13.
After flowing upward in the interior, it overflows from the upper end of the water level adjusting pipe 13 and is drained to the drainage channel 3 through the tubular space 15 and the connecting pipe 14. Therefore, the water level in the rice field is the same as the upper end of the water level adjusting pipe 13. Become a level. Therefore, by changing the height of the water level adjusting pipe with the operating device 9, the water level of the rice field can be changed to a desired level. The configuration of the operating device 9 is common to both claim 1 and claim 2, and will be described later.

In the embodiment of claim 2, one end is connected underground in the middle of the underground conduit 2 and the other end is a horizontal pipe 7 of the joint pipe.
The water intake pipe 21 that shallowly projects from the closed one end 7a into the inside of the horizontal cylinder and the diameter smaller than the vertical cylinder 8 of the joint cylinder, rises inside the vertical cylinder, and the open upper end is in the middle of the inside of the vertical cylinder. End of the upward pipe 22, a vertically movable water level adjusting pipe 23 attached to the upper end of the upward pipe, and the internal water level adjusting pipe is moved vertically from the upper end of the vertical cylinder to position the upper end of the water level adjusting pipe. Is connected to the lower end of the upward pipe 22 inside the horizontal tube of the joint cylinder and penetrates through the closed other end of the horizontal cylinder. A pipe 24 connects the upward pipe 22 to the drainage channel 3.

The upward pipe 22 and the connecting pipe 24 may be an L-shaped integral pipe, or may be separate pipes connected to each other by a right-angle elbow inside the horizontal cylinder 7 and below the vertical cylinder 8.

The water flowing from the water intake pipe 21 into the inside of the horizontal cylinder rises in the cylindrical space 25 formed between the outer circumference of the upward pipe 22 and the water level adjusting pipe 23 and the inner circumference of the vertical cylinder 8. Countercurrent, overflowing from the upper end into the water level adjusting pipe 23,
3. Flowing down inside the upward pipe 22, the other end 7b of the horizontal cylinder
It is drained to the drainage channel 3 by the communication pipe 24 which penetrates through

The water flowing in the underdrain pipe closed by the water bar in this way is supplied from the inside of the horizontal cylinder to the upward pipe 22 and the water level adjusting pipe 2.
3 flows upward in a cylindrical space 25 formed by the outer circumference of the vertical cylinder 8 and the inner circumference of the vertical cylinder 8, and then overflows from the upper end of the water level adjusting pipe 23 into the inside of the pipe, and passes through the upward pipe 22 and the connecting pipe 24. Drainage channel 3
The water level in the rice field is at the same level as the upper end of the water level adjusting pipe 23. Therefore, by changing the height of the water level adjusting pipe with the operating device 9, the water level of the rice field can be changed to a desired level.

Attached to the upper ends of the upward pipes 12 and 22,
The vertically movable water level adjusting pipes 13 and 23, which adjust the upper end position by the operating device 9 and determine the water level level of the rice field by the adjusted upper end position, are arranged in the bellows type vertical direction as shown in FIGS. It may be a bellows 31 that can be expanded and contracted, or a plurality of slide tubes 32 that are vertically movably fitted as shown in FIG.

The water level adjusting pipes 13, 2 are operated by the operating device 9.
3. In FIG. 1, in order to move the upper end of the bellows 31 up and down,
The connecting plate 33 is fixed to the upper end of the water level adjusting pipe in the radial direction, for example, in the diametrical direction (see the enlarged view of FIG. 1). Since the connecting plate 33 is fixed in the radial direction, the water rising in the water level adjusting pipe overflows from the upper end into the outer cylindrical space 15 as in the embodiment of FIG. There is no obstacle for the water rising in the cylindrical space 25 to overflow into the water level adjusting pipe from the upper end.

The operating device 9 of FIG. 3 stands vertically with the lower end fixed to the center of the connecting plate 33, and penetrates through the central hole 35 of the lid 34 detachably attached to the upper end of the vertical cylinder 8 on the ground. An operation rod 41 protruding inward, a fixing plate 42 radially fixed above the inside of the vertical cylinder 8 in a radial direction, for example, and through which the operation rod 41 penetrates a central hole, and a hollow portion. A male screw cylinder 43 fixed on the fixing plate in a state of communicating with the central hole of the fixing plate 42, a cap nut 44 threadedly engaged with the male screw cylinder from above, and located inside the cap nut. The male screw cylinder 43 and the cap nut 4
4 and an O-ring 45 arranged between them.

The operating rod 41 standing from the center of the connecting plate 33 passes through the center hole of the fixing plate 42, the hollow portion of the male screw cylinder 43, the O-ring 45, and the inside of the cap nut 44. When the O-ring 45 is tightly screwed into the male screw on the outer periphery of the male screw cylinder by the cap nut, the O-ring 45 is pressed from the surroundings and the operating rod 41 is tightened from the surroundings to grip the operating rod with respect to the fixed plate 42 in a vertically immovable manner. It is preferable that a scale 46 indicating the water level corresponding to the position of the upper end of the water level adjusting tube is written on the operation rod 41 in the vertical direction.

In order to adjust the position of the upper end of the water level adjusting pipe to a predetermined water level, the lid 34 is removed from the upper end of the vertical cylinder 8, the lid is pulled up along the operating rod, and the center hole 35 is moved upward from the upper end of the operating rod. And remove the lid from the upper end of the operating rod.
Then, from the upper end of the vertical cylinder 8, the cap nut 44 is loosened to stop the tightening of the O-ring 45 around the operating rod, and the operating rod is moved up and down along the hollow portion of the male screw cylinder to extend the water level adjusting pipe upward. Or the position of the upper end of the water level adjusting pipe is changed by contracting it downward, and when the position of the upper end of the water level adjusting pipe reaches a desired level, the cap nut 44 is strongly screwed into the male screw cylinder 43 again, and the O-ring 45 is used. Operating rod 41
Is tightened from the periphery to be fixed, and the position of the upper end of the water level adjusting pipe is brought to a desired water level level.

As described above, the operating rod 41 is provided with the scale 46 indicating the water level, and the upper ends of the water level adjusting pipes 13 and 23 are set to desired values depending on which of the scales 46 is positioned on the upper end of the cap nut 44. Being able to reach the water level allows the adjustment work to be done quickly and easily. The range in which the water level can be changed up and down by expanding and contracting the water level control pipe is 30 above the rice field.
From about cm to about 70 cm underground, it may be about 1 m in the vertical direction. When the upper end of the water level control pipe is at the highest position, the water level rises from the rice field surface of the paddy field, and the fallow field is used as a paddy field for rice cultivation again. It is preferable to be able to do so.

When the positions of the upper ends of the water level adjusting tubes 13 and 23 are adjusted to the desired water level in this way, the central hole 35 of the lid 34 is fitted onto the operating rod 41 projecting upward from the upper end of the vertical cylinder 8 so that the operating rod is operated. The lid 34 is pulled down along 41, and the upper end of the vertical cylinder 8 is covered with the lid 34.

In the operating device 9 of FIG. 3 described above, as the positions of the upper ends of the water level adjusting tubes 13 and 23 are raised, the length of the operating rod 41 projecting upward from the central hole of the lid 34 becomes longer, and the ridge 5 It may be a hazard as well as a person passing by on the road, a cultivator traveling on the ridge 5, and the like. Therefore, the operation rod 41 is composed of a plurality of expandable and contractible inner and outer pipe materials which are slidably fitted in the vertical direction, and when the position of the upper end of the water level adjusting pipe is adjusted to a desired water level, It is preferable to shorten the length so that the length protruding upward from the central hole 35 of the lid 34 can be made as short as possible.

The operating device 9 shown in FIG.
Connection plate 3 fixed radially on the upper end of 3, for example diametrically
It penetrates through the center hole of 3 slidably in the vertical direction, and the upper end is
A downward operation rod 51 that is detachably attached to the upper end of the vertical cylinder 8 and is fixed to the central portion of the lid 34 that closes the upper end of the vertical cylinder by bonding or screwing, and a hollow portion above the central hole of the connecting plate 33. A male screw cylinder 52 which is fixed by communicating with each other, and a cap nut 53 which is threadedly engaged with the male screw cylinder 52 so as to cover the male screw cylinder 52 from above.
The O arranged between the male screw cylinder 52 and the cap nut 53
And a ring 54. The operating device of the embodiment shown in FIGS. 1 and 2 has the structure shown in FIG.

The operating rod 51 penetrating the center hole of the connecting plate 33 slidably in the vertical direction is a hollow portion of the male screw cylinder 52, O
The O-ring 54 passes through the ring 54 and the cap nut 53, and when the cap nut 53 is strongly screwed into the male screw on the outer circumference of the male screw cylinder 52, the O ring 54 is pressed from the periphery by the cap nut.
Tighten the operating rod from around and connect the operating rod to the connecting plate 3
It is fixed so that it cannot move vertically with respect to 3. This operation is performed by removing the lid from the upper end of the vertical cylinder and operating rod 5 with the upper end fixed to the lid.
1 is pulled up to extend the water level adjusting tubes 13 and 23 upward, and the connecting plate 33 attached to the upper end of the water level adjusting tube is taken out from the upper end of the vertical cylinder 8. It is preferable that a scale 55 indicating the water level corresponding to the position of the upper end of the water level adjusting pipe is written on the operation rod 51 in the vertical direction.

In order to adjust the positions of the upper ends of the water level adjusting pipes 13 and 23 to a predetermined water level, the lid 34 is removed as shown by the broken line in FIG. 4, and the operating rod 51 is pulled up integrally with the lid to connect the connecting plate. With 33, the upper parts of the water level adjusting pipes 13 and 23 are stretched upward and taken out from the upper end of the vertical cylinder 8, and the cap nut 53
To tighten the O-ring 54 from around the operating rod 51, and move the operating rod up and down along the hollow portion of the male screw cylinder 52 to extend or contract the water level adjusting pipes 13 and 23 downward. By changing the position of the upper end of the water level adjusting pipe by this, when the position of the upper end of the water level adjusting pipe reaches a desired level, the cap nut 53 is strongly screwed into the male screw cylinder 52 again,
The operation rod 51 is tightened from around by the O-ring 54 to fix the water level adjusting pipe and the operation rod, and the position of the upper end of the water level adjusting pipe is set to a desired water level level. Then, the operation rod drawn out of the vertical cylinder and the water level adjusting tube are housed inside the vertical cylinder, and the lid 34 to which the upper end of the operation rod is fixed is put on the upper end of the vertical cylinder. Insert the upper end of the operating rod into this lid 34,
It is preferable that the holding cylinder 36 that is fixed by adhesion or the like be provided downward.

If the operating rod 51 is provided with a scale 55 indicating the water level, which of the scales 55 will be the cap nut 53.
If the upper ends of the water level adjusting pipes 12 and 23 can be brought to the position of a desired water level level depending on whether they are located at the upper end of the, the adjustment work can be performed quickly and easily. The range where the water level control pipe can be expanded and contracted up and down to change the water level up and down is about 30 cm above the rice field and about 70 cm below the ground up to about 1 m in the vertical direction. In this case, it is preferable that the water level rises above the surface of the paddy field so that the fallow field can be used as a paddy field again for rice cultivation.

In the operating device of FIG. 4, the upper end is covered with a lid 34.
In the middle of the operation rod that vertically movably penetrates through the central hole of the connecting plate 33 and the hollow portion of the male screw cylinder 52 fixed on the connecting plate 33, the O-ring is compressed from the periphery by a cap nut. By tightening the operating rod to change and fix the position of the upper end of the water level adjusting pipe, the operating rod does not project above the ridge. Therefore, the operation rod does not trip over and fall, and the progress of agricultural work vehicles such as a cultivator is not hindered.

In the embodiment shown in FIG. 4, the bellows are used for the water level adjusting tubes 13 and 23, but as shown in FIG. 5, a plurality of stages of telescopic slide tubes 3 are provided at the upper ends of the upward tubes 12 and 22.
The operating device of FIG. 4 can also be used when 2-1, 32-2, and 33-3 are used as water level adjusting tubes.
Further, the slide tube that expands and contracts in a plurality of stages can also be used as a water level adjusting tube of the operating device of FIG.

[0031]

As is apparent from the above, according to the present invention,
It is possible to adjust the water level not only in paddy fields where rice is grown, but also in paddy fields that have been made into fallow fields according to the root depth of the plant to be cultivated there. Therefore, without dying the plant by rooting due to overhumidity or dying the plant due to lack of water, it is possible to constantly grow the plant by giving an appropriate amount of water and increasing the yield. To adjust the water level up and down, screw the male rod into which the operating rod penetrates from above, and press the internal O-ring from around to loosen the cap nut that holds the operating rod in the vertical direction. This can be easily changed by moving the operating rod up or down to bring the position of the upper end of the water level adjusting pipe to a position of a predetermined water level and then screwing the cap nut again.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of a water level adjusting device of the present invention and an enlarged view of a part thereof.

FIG. 2 is an explanatory view of another embodiment of the water level adjusting device of the present invention.

FIG. 3 is an enlarged view of an example of an operating device that moves up and down the upper end of a water level adjusting pipe (bellows) according to the present invention.

FIG. 4 is an enlarged view of another example of the operating device for moving the upper end of the water level adjusting pipe (bellows) of the present invention up and down.

FIG. 5 is an enlarged view showing a state in which the upper end of a water level adjusting pipe, which is a slide pipe fitted in a large amount inside and outside, is moved up and down by the operation device of FIG. 4;

[Explanation of symbols]

1 rice field 2 Underdrain 3 tillage channels 4 locks 5 ridges 6 joint cylinder 7 Joint horizontal tube 8 joint vertical cylinder 9 Operating device 11,21 Intake pipe 12,22 Upward tube 13,23 Water level control tube 14,24 connecting pipe 15,25 tubular space 31 Bellows 32-1, 32-2, 32-3 slide tube

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takao Karasawa             2-8-4 Nishishimbashi, Minato-ku, Tokyo Eikichi             Business

Claims (7)

[Claims] 1. A water level adjusting device in a rice field, which is laid underground in a rice field and has a downstream end portion for draining irrigation water supplied to the rice field to a drainage channel, which is attached to a underdrain tube which is opened and closed by a lock bar. In the middle of the, the intake pipe with one end connected underground, and the vertical pipe whose upper end is located on the surface of the rice field are provided in the middle of the horizontal pipe, and the other end of the intake pipe penetrates the closed one end of the horizontal pipe. It is connected to the other end of the water intake pipe in the above-mentioned joint cylinder and an inverted T-shaped joint cylinder that is buried in the ground, and rises inside the above-mentioned vertical cylinder with a smaller diameter than the vertical cylinder of the joint cylinder. Then, the open upper end ends in the middle of the vertical pipe, the vertically movable water level adjustment pipe attached to the upper end of the upward pipe, and the internal water level adjustment pipe vertically from the upper end of the vertical pipe. Move it and adjust the position of the upper end of the water level adjusting pipe to the water level setting level of the rice field. A water level adjusting device in a rice field, comprising the other end of the horizontal cylinder of the joint cylinder connected to a drainage channel. 2. A water level adjusting device for a rice field, which is laid underground in a rice field and has a downstream end for draining irrigation water supplied to the rice field to a drainage channel attached to a underdrain pipe opened and closed by a barb. A vertical cylinder located on the surface of the horizontal cylinder in the middle of the horizontal cylinder, and one end of the horizontal cylinder is underground buried in the middle of the underdrain pipe; A smaller diameter than the vertical tube, rises inside the vertical tube, the open upper end ends in the middle of the vertical tube, and a vertically movable water level adjustment tube attached to the upper end of the upward tube, An operating device for moving the internal water level adjusting pipe in the vertical direction from the upper end of the vertical pipe to adjust the position of the upper end of the water level adjusting pipe to the water level setting level of the rice field, and the lower end of the upward pipe to the side of the joint pipe. Characterized by connecting to the drainage channel with a connecting pipe that penetrates the closed other end of the cylinder A water level control device in the rice field. 3. The water level adjusting device according to any one of claims 1 and 2, wherein the water level adjusting pipe attached to the upper end of the upward pipe is a bellows that can expand and contract in the vertical direction. A water level adjusting device in a rice field. 4. The water level adjusting device according to any one of claims 1 and 2, wherein the water level adjusting pipe attached to the upper end of the upward pipe is fitted to the upward pipe so as to be vertically movable. A water level adjusting device in a rice field, which is a slide pipe. 5. The water level adjusting device according to any one of claims 1 to 4, wherein the operating device for adjusting the position of the upper end of the water level adjusting pipe to the water level setting level in the rice field is the water level. The lower end is fixed vertically to the center of the radial connecting plate provided on the upper end of the adjusting pipe, stands vertically, and the operation rod protruding upward from the upper end of the vertical cylinder and radially fixed above the inside of the vertical cylinder. A fixing plate through which the operation rod penetrates the central portion, fixed on the fixing plate, a male screw cylinder through which the operating rod penetrates the hollow portion, and a cap nut screw-engaged by covering the male screw cylinder from above, A water level adjusting device in a rice field, comprising an O-ring which is located inside the cap nut and which is pressed by screwing the cap nut into a male screw cylinder to immovably tighten the operating rod from the periphery. 6. The water level adjusting device for a rice field according to any one of claims 1 to 4, wherein an operating device for adjusting a position of an upper end of the water level adjusting pipe to a water level setting level of the rice field is provided.
A lid that closes the upper end of the vertical cylinder so that it can be opened and closed, a male screw cylinder that is fixed on the center of a radial connecting plate that is provided at the upper end of the water level adjustment pipe, and a detachably attached lower surface of the lid that lowers. An operating rod that penetrates the hollow portion of the male screw cylinder and the connecting plate, a cap nut that is screw-engaged by covering the male screw cylinder from above, and that is located inside the cap nut, and screw the cap nut into the male screw cylinder. A water level adjusting device in a rice field, which comprises an O-ring that is pressed by an operator to immobilize the operation rod from the periphery. 7. The water level adjusting device for a rice field according to any one of claims 5 and 6, wherein a scale indicating a water level is provided on the outer surface of the operating rod. Water level adjuster.