JP2000106770A - Negative pressure difference irrigation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject system designed to easily control the water feed to and water discharge from soil. SOLUTION: This negative pressure difference irrigation system is so designed as to embed a porous pipe 2 into soil 1, saturate the inside of the porous pipe 2 with water from a water reservoir, and by the aid of the negative pressure difference between the soil in contact with the porous pipe 2 and the inside of the porous pipe 1, either leaching the water inside the porous pipe 2 into the soil 1 or taking the water in the soil 1 into the porous pipe 2 is performed, wherein such a means so to automatically set the level in the water reservoir constant through raising/lowering the water level is furnished so as to be vertically movable, and by moving the means vertically, the height difference between the porous pipe 2 and the level in the water reservoir is ensured to be regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a negative pressure differential irrigation system.

[0002]

2. Description of the Related Art In order to grow plants well, it is extremely important to properly control water supply and drainage and to always maintain the root zone at an appropriate humidity. Negative pressure differential irrigation is one of the water-saving irrigation methods for efficiently using water when growing plants. This method was first introduced by BE Livingstone in 1934, and its principle was to saturate a porous tube buried in soil with water and to reduce the water pressure in the tube to a negative pressure. Irrigation is performed by the difference between the negative pressure of the soil in contact with the porous pipe and the negative pressure in the pipe.

In this negative pressure differential irrigation system, the method of controlling the amount of water supplied to the soil or the amount of drainage from the soil is as follows: (1) Changing the performance of the porous pipe. (Change porosity, pipe thickness, wall thickness, length, etc.) (2) Change the installation density of porous pipes in the soil. (3) Various methods have been tried, such as changing the depth at which the porous tube is buried.

However, in these methods, once the porous pipe is installed in the soil, it is difficult to change the conditions thereafter. Therefore, the present inventors examined whether the amount of water supply and drainage can be controlled relatively easily by changing the set negative pressure value (the difference between the position of the pipe and the water level of the water supply and drainage tank). As a specific method, several bricks were placed under the water supply / drainage tank, and the water level was changed by increasing or decreasing the number of the bricks, or the tank was moved up and down with a jackie or the like, but this was not a good solution.

[0005]

Therefore, as a result of various investigations to find a method for more easily controlling the amount of water supply and drainage, a structure in which the ball tap and the like can be moved up and down in a tank by a method of keeping the water level constant by a ball tap and the like. As a result, the present inventors have found that the water level in the tank can be easily adjusted, and have reached the present invention.

[0006]

That is, the gist of the present invention is to embed a porous pipe in soil, saturate the inside of the porous pipe with water from a water storage section, and reduce the negative pressure of the soil in contact with the porous pipe. And a negative pressure difference irrigation system configured to allow water in the porous tube to leach into the soil or to take in soil water into the porous tube due to the difference in the negative pressure in the porous tube. A means for automatically keeping the water level of the water storage section constant is provided so as to be movable in the vertical direction, and by moving the means in the vertical direction, the height difference between the porous pipe and the water level of the water storage section is adjusted. A negative pressure differential irrigation system configured as described above.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, in the present invention, a porous tube is buried in soil. The soil is usually a natural soil, and a so-called artificial soil such as a culture soil is also common.However, even if it does not contain organic matter, it can be used for plant cultivation by the negative pressure difference irrigation system of the present invention. Not restricted.

[0008] In the present invention, a porous pipe is buried in the soil. The embedding depth is not particularly limited, and is usually preferably about 5 to 50 cm from the soil surface. If it is too shallow, it is unfavorable because it is easily affected by the temperature of the ground surface and water evaporates easily. If it is too deep, it is difficult to reach the root zone of the plant, which is not preferable. In general, the material of the porous tube is preferably ceramic, concrete, or porous glass. However, a sintered material of a metal, a porous molded body made of plastics such as polyethylene, polypropylene, and rubber, and a material that can be used as a filter material Can be used. A hydrophilic material or a material subjected to a hydrophilization treatment is preferable from the viewpoint of allowing water vapor or water to pass through. These porous materials have a pore size of 0.01-20.
It is desirable to have pores in the range of about 0 μm. If the pores are finer than this, clogging is likely to occur during use, and the flow resistance of the fluid is large, so that the flow of water is poor. It tends to flow in and maintain a negative pressure. A particularly desirable pore diameter is in the range of about 0.1 to 50 μm, and a pore diameter distribution is particularly preferable. In particular, a cylinder having a pore diameter of about 10 μm obtained by molding and firing porcelain clay having a large amount of quartz is preferable.

[0009] These porous materials are usually formed into a cylindrical shape and used as a porous tube. The inner diameter, wall thickness, and length are not particularly limited, but if it is too small, the resistance when flowing water is large, and if it is too large, a large amount of water is circulated in order to flush out bubbles generated or mixed inside. It is necessary to make it. Therefore, usually, the inner diameter is about 3 to 100 mm, preferably 5 to 50 mm, the wall thickness is about 1 to 30 mm, preferably 3 to 15 mm, and the length is not particularly limited. Those that are poor and are easily damaged by flexural stress can be made shorter, and those that are more flexible such as plastic materials can be made longer to reduce the number of connection points. In order to connect a plurality of porous pipes, it is common to use a tube such as polyvinyl chloride or polyethylene, or a pipe material, and it is convenient to use a metal pipe, a pipe connector, or the like.

At the time of connection, it is preferable to use a tube or the like having a smooth inside, and furthermore, to prevent a sudden change in the tube diameter so that pressure loss is hardly generated. In general, the arrangement of the porous tubes is such that a plurality of porous tubes are arranged in one row or a plurality of rows are arranged in parallel. In the present invention, a water reservoir for supplying water to the porous tube is provided, and the type of water is not limited as long as the water is suitable for growing plants. In this case, a fertilizer or the like can be dissolved if necessary.

The supply of water to the water storage section can be appropriately performed, for example, from a water supply port provided above the liquid level of the water storage section. Further, water can be circulated from a water receiving portion provided downstream of the porous pipe and supplied to the water storage portion. Also,
The water storage unit and the water receiving unit can also be used. By conducting water from the water storage section, water is saturated in the water flow path between the porous pipe and the piping material and the water storage section, and when the on-off valve is closed, the water is in a stationary state between the on-off valve and the water receiving tank. And the pressure in the tube becomes negative.

For setting the negative pressure, generally, for example, a water storage tank is provided at a position lower than the surface on which the porous pipe is laid, usually 10 cm to 3 m, and the flow of water by the siphon is adjusted. Then, adjust the height of the end of the open end to adjust the negative pressure and the flow rate of water generated in the pipe.If the water tank is installed higher than the surface where the porous pipe is laid, attach a control valve. For example, a method of adjusting the flow of water to a negative pressure by adjusting the flow of water.

In the present invention, by adopting such a configuration, the water in the porous tube is leached into the soil by the difference between the negative pressure of the soil in contact with the porous tube and the negative pressure in the porous tube. Alternatively, the water in the soil can be taken into the porous tube. According to the present invention, in such a negative pressure differential irrigation system, means for automatically keeping the water level of the water storage section constant by raising and lowering the water level is provided so as to be movable in the vertical direction, and the means is moved in the vertical direction. By doing so, the height difference between the porous pipe and the water level in the water storage section is adjusted.

That is, as means for automatically keeping the water level constant by raising and lowering the water surface, there is an adjusting means such as a ball tap. According to these means, the water level of the water storage section automatically becomes constant, but in the present invention, this means itself is configured to be movable in the vertical direction. That is, for example, in the case of a ball tap, the ball tap is fixed by a fixing bar, and the fixing can be performed by a screw, for example. Then, the fixing screw is loosened so that the fixing screw can be fixed at any position that is continuous or discontinuous in the vertical direction.

The vertical position is set in such a range that the height difference (Δh) between the porous pipe and the water level in the water reservoir is usually 5 to 100 cm. When the soil is dried, the water can be leached into the soil with a large amount of water in the porous pipe by moving the means upward as appropriate to raise the water level of the water storage section and reduce the height difference. . On the other hand, when the soil is in a wet state, the water in the porous tube can be appropriately moved downward to reduce the leaching of the water in the porous tube into the soil water, or the soil water can be taken into the porous tube.

FIG. 1 shows an embodiment of the negative pressure difference irrigation system of the present invention. In FIG. 1, reference numeral 1 denotes soil for plant cultivation, in which a plurality of porous tubes 2 are buried. The porous tube 2 is connected to a water storage tank 6 (provided at a position lower than the porous tube 2) by conduits 3 and 3 '(the conduit 3 is provided with a valve 4).
The conduit 3 is connected via a valve 4 to a measuring tank 5 provided above and a water supply port of a ball tap. The ball tap 7 is attached to a jig fixing rod 8 fixed in the water storage tank 6 with a lid at an upper portion thereof by a screw so as to be movable at an arbitrary position.

Reference numeral 9 denotes an overflow port of the water storage tank 6.
In this system, when the valves 4 and 4 'are opened and water is supplied from the measuring tank 5, the water supply into the water storage tank 6 is stopped at a constant water level by the ball tap 7. Then, when the valve 4 'is closed, the water in the water storage tank 6 is in communication with the porous body 2 through the conduits 3 and 3', and thus water is supplied to the soil or drained from the soil by negative pressure differential irrigation. When it is necessary to increase the amount of water supply, the mounting position of the ball tap 7 may be moved upward as needed. On the other hand, when the amount of drainage needs to be increased, the mounting position of the ball tap 7 may be moved downward appropriately. Let it.

[0018]

According to the negative pressure difference irrigation system of the present invention, the amount of water supplied to the soil or the amount of drainage from the soil can be easily controlled.

[Brief description of the drawings]

FIG. 1 shows one embodiment of a negative pressure differential irrigation system of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Soil 2 Porous pipe 3,3 'conduit 4,4' valve 5 Measuring tank 6 Water tank 7 Ball tap 8 Jig fixing rod 9 Overflow port

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takaharu Yamamoto 1-1 Kurosaki Castle Stone, Yawata Nishi-ku, Kitakyushu City, Fukuoka Prefecture Inside the Kurosaki Office of Mitsubishi Chemical Corporation (72) Inventor Takashi Matsumoto 1 Kurosaki Castle Stone, Yawata-Nishi-ku, Kitakyushu City, Fukuoka Prefecture No. 1 Kurosaki Office of Mitsubishi Chemical Corporation

Claims (1)

[Claims] 1. A porous tube is buried in soil, the inside of the porous tube is saturated with water from a water reservoir, and the difference between the negative pressure of the soil in contact with the porous tube and the negative pressure in the porous tube is caused by the difference. Pressure differential irrigation system configured to bleed the water in the porous pipe into the soil or take in the soil water into the porous pipe, and automatically keep the water level in the water reservoir constant by raising and lowering the water level A negative pressure differential irrigation system, wherein the means is provided so as to be movable up and down, and the means is moved up and down to adjust the height difference between the porous tube and the water level in the reservoir.