JP5286205B2 - Watering method to soil - Google Patents

Description

  The present invention relates to a method for irrigating soil. More specifically, the present invention relates to a method for irrigating soil using a water pressure difference.

  Many methods for irrigating soil where plants are cultivated have been proposed and put into practical use. One of them is the water-saving irrigation method introduced in 1934 by BE Livingston. The principle is that a porous tube is buried in the soil where plants are cultivated, water is saturated in this porous tube, and when the water pressure of the soil is low, the soil is irrigated, and when the water pressure in the soil is high This is a method of irrigating the soil using a water pressure difference, in which extra water is taken into (sucked into) the porous tube, and has a feature that the amount of water used is small.

Techniques described in Japanese Patent Application Laid-Open Nos. 9-9802, 9-308396, and the like have been proposed as examples of practical application of the water irrigation method using the water pressure difference. According to these proposed methods, gas such as air dissolved in water filled in the water supply system (or water flow system) including porous tubes and conduits becomes bubbles due to environmental changes such as temperature. It has been found that there is a problem that it adheres to the inner surface of the porous tube and closes the pores, and even if there is a pressure difference between the inside and the outside of the porous tube, moisture cannot be supplied to the soil. The present inventors diligently investigated this problem and proposed a method described in Japanese Patent No. 4173228. According to the method described in this patent publication, the remaining bubbles can be almost completely removed by quickly passing water through the water passage system at a water pressure of ² to 3 kg / cm ² , and the inside and outside of the porous tube can be removed. When the pressure difference occurred and the water pressure in the porous tube was high, water could be supplied to the soil.

  However, as a result of further investigations after that, even if the bubbles remaining in the water supply system were almost completely removed, there was a case where a pressure difference did not occur inside and outside the porous tube. As a result of investigating the cause, the following was found. That is, the soil changes due to a sudden change in the external environment, for example, a rapid increase in the outside air temperature, a rapid evaporation of soil water due to air drying (low humidity), and a rapid absorption of soil water by plants in the growing season. It was found that the soil was dried and contracted, and the soil in contact with the surface of the porous tube was peeled off from the surface of the porous tube. Irrigation to the soil using the water pressure difference requires that the soil is in contact with the surface of the porous tube and that the soil is in a state capable of maintaining capillary action. If the soil is peeled off from the surface of the porous tube, irrigation to the soil using the water pressure difference becomes impossible.

JP-A-9-9802 Japanese Patent Laid-Open No. 9-308396 Japanese Patent No. 4173228

  The inventor of the present invention has problems that existed in the above-mentioned prior art, that is, rapid increase in outside air temperature, rapid evaporation of soil water due to air drying (low humidity), soil water caused by plants in the growing season. As a result of diligent research to provide a irrigation technique that enables stable irrigation of soil using a water pressure difference even when a sudden change occurs in the external environment such as rapid absorption, the present invention has been completed.

  In order to solve the above-mentioned problem, in the present invention, a plurality of porous tubes having pores provided on the wall surface are arranged and connected at appropriate positions of a water-permeable conduit not provided with pores on the wall surface. A water pipe is buried in the soil, and both ends of this water pipe are connected to the water tank below the position of the porous pipe. Normally, the water surface of the water tank is the same position (horizontal position) or lower position as the porous pipe. The water pipe is saturated with water from the water tank, the water pressure in the porous pipe is (a), and the water pressure contained in the soil in contact with the porous pipe surface is (b), When (a)> (b), the moisture in the porous tube is exuded to the soil side, and when (a) <(b), the moisture contained in the soil is taken into (sucked into) the porous tube. In the irrigation method using the water pressure difference, the water in the reservoir is intermittently supplied to the reservoir. A method for irrigating soil using water pressure difference, characterized in that the position of the water is slightly higher than the position of the porous tube embedded in the soil and the water pressure in the water tank is made slightly positive To do.

The present invention has a particularly remarkable effect as follows, and its industrial utility value is extremely large.
1. According to the irrigation method to the soil using the water pressure difference according to the present invention, the rapid increase of the outside air temperature, the rapid evaporation of the soil water due to the drying (low humidity) of the air, the soil by the plant in the growing season Even if a sudden change occurs in the external environment due to sudden absorption of water, the soil can be irrigated stably and continuously.
2. According to the irrigation method to the soil using the water pressure difference according to the present invention, it is not necessary to constantly monitor the water level of the water tank, the irrigation work is simple, and there is no concern about excessive irrigation.

It is the schematic which shows an example which is implementing the method of this invention. It is the schematic which shows the other example which is implementing the method of this invention.

  Hereinafter, the present invention will be described in detail. The present invention relates to a method of irrigating water to a plant cultivated in soil. A porous tube (hereinafter simply referred to as a conduit) in which pores penetrating the wall surface are provided at appropriate positions of a conduit (which may be simply referred to as a conduit (A) hereinafter) in which pores are not provided on the wall surface. (It may be described as (B)). A plurality of connected water pipes are buried in the soil, and the water pipe is saturated with water so that water penetrates from the pores of the porous pipe to the outside. The irrigation method uses the permeated water for plant growth and cultivation.

  The soil used in the method of the present invention is usually not particularly limited as long as it can retain moisture between particles and can grow plants, and even natural soil is artificially crushed and mixed. Alternatively, it may be a mixture of artificial soil and natural soil. The soil includes all the soils based on the classification of the “Japan Unified Soil Classification Method”. That is, the soil is classified into soil particles (leki particles, sand particles), fine particles, and high organic particles (peat, black mud) depending on the soil material, but any of them may be used. The particles having a large particle diameter are not limited to single particles but are preferably mixed with sand particles, fine particles (silt, viscous soil, organic soil, volcanic ash clay) and the like. The soil with a lot of lexic particles can be improved to a soil suitable for plant growth by a method of obtaining fine particles and highly organic particles. The soil to which the method of the present invention can be applied is preferably a flat soil having no slope. The soil includes fields and greenhouses with various areas, potted soil with a small area, and planter soil.

  The conduit (A) in which pores are not provided on the wall surface constituting the water pipe constitutes a portion of the water pipe that is not embedded in the soil, and a porous pipe (at a fixed or arbitrary interval in the portion embedded in the soil) B). The conduit (A) is preferably a conduit (tube) manufactured by an extrusion method using a thermoplastic resin as a raw material. Examples of the resin include polyethylene, polypropylene, polyvinyl chloride, polybutene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polycarbonate, and polyamides. Among these, polyvinyl chloride, polyethylene, and polypropylene are preferable. There are no restrictions on the inner diameter, wall thickness, length, etc. of this conduit, but if the inner diameter is too small, the resistance of the water during water feeding is large, and if it is too large, bubbles generated inside the water pipe or the outside of the water pipe It is necessary to circulate a large amount of water in order to discharge air bubbles mixed from the water. The inner diameter and thickness of the conduit vary depending on the soil environment (area, field or greenhouse, soil type, plant type to be cultivated, etc.), but the inner diameter is usually 1 to 50 mm, preferably 3 It is selected in a range of ˜30 mm. The wall thickness is selected in the range of 0.5 to 20 mm, preferably 1 to 10 mm in proportion to the inner diameter of the conduit.

  The pores provided in the wall surface of the conduit (B) function to pass water or water vapor from the inside of the porous tube to the outside of the porous tube or from the outside of the porous tube to the inside of the porous tube. . The material of the porous tube is ceramic, concrete, porous glass, metal sintered body, porous conduit made of thermoplastic resin such as polyethylene, polypropylene, rubber, etc., as well as metal sintered body and filter material Examples of the material that can be formed into a cylindrical shape. Among them, those obtained by molding and firing ceramic clay with a lot of quartz are preferable.

  The pores of the conduit (B) are selected in the range of pore diameters of 0.01 to 200 μm. If it is smaller than the lower limit, clogging is likely to occur during use, and the resistance of the water to be fed is large.If it is larger than the upper limit, the water level in the water tank is significantly lower than the horizontal position of the porous conduit. The air contained in the soil is sucked to easily drop the water in the water pipe into the water storage tank, and the saturated state of the water in the water pipe cannot be maintained. A more preferable range of the pore diameter is 0.1 to 50 μm. The inner diameter, thickness, etc. of the conduit (B) are preferably the same as those of the conduit (A), but they may not be the same. It is preferable to treat the pores with a hydrophilic substance because water and water vapor easily pass through. If the conduit (B) is too short, the operation for connecting to the conduit (A) to form a water pipe becomes complicated, and if it is too long, the cost increases and neither is desirable. Usually, it is selected in the range of 30 to 200 mm.

  The procedure for preparing the water pipe and burying it in the soil is as follows. First, depending on the type of soil in which the water pipe is buried, the type of plant cultivated in the soil, the type, diameter, inner diameter and thickness of the conduit (A) At the same time, the material type, diameter, inner diameter, wall thickness, hole diameter, etc. of the conduit (B) are selected. Next, the only portion of the water pipe that is not embedded in the soil is the conduit (A), and the portion embedded in the soil is the conduit (A) that is alternately or regularly spaced from the conduit (B) with the conduit (A). To be connected to the water. The number of pipes (B) connected to the pipe (A) shall be plural, but the number and interval will depend on the soil environment (area, field or greenhouse, soil type, plant type to be cultivated, etc.) Can be selected as appropriate. It is preferable to use a connection tool at the joint between the conduit (A) and the conduit (B). In addition to connecting the conduit (A) and the conduit (B), the connector functions to adjust both when the diameter, the inner diameter, the wall thickness, and the like are different. The connection tool may be made of thermoplastic resin, metal, or the like.

  What is connected and made long in this way is buried in soil to form a water pipe. In addition to the method of embedding a long water pipe in advance in the soil, the condition of the soil (whether it is flat or erected, the whole area, and if erected, the width and length of the ridge) Etc.) may be connected while adjusting the length of the conduit (A) and the length and number of the conduit (B), and may be sequentially embedded in the soil. The depth at which the water pipe is buried in the soil can be selected as appropriate according to the soil environment (region, field or greenhouse, type of soil, type of plant to be cultivated, etc.). It is selected in the range of 50 to 200 mm.

  The water tank functions to store water for irrigating the soil. Both ends of the water pipe are connected to the water tank below the position of the porous pipe, and the water pipe is saturated with water and connected to the water tank (see FIGS. 1 and 2). The water surface of the water storage tank is maintained at the same position (horizontal position) as the porous pipe or at a slightly lower position. Even if the water level of the water storage tank is lower than the horizontal position of the porous tube, the water saturated in the water supply tube can maintain a saturated state due to the siphon effect.

  In the irrigation method according to the present invention, when the water pressure in the porous tube is (a) and the water pressure contained in the soil in contact with the porous tube surface is (b), (a)> (b) Sometimes, water in the porous tube is leached to the soil side, and when (a) <(b), irrigation using a water pressure difference is made so that the moisture contained in the soil is taken into (sucked into) the porous tube. Is the method. When the water pressure is in the former relationship, water is saturated in the water pipe and the outer surface of the pipe (B) is covered with soil containing moisture even if the water surface of the water tank is lower than the porous pipe. In this state, water oozes into the soil by capillary action and continues to be supplied to the plant roots. When the water pressure is in the latter relationship, the water surface is lower than the porous tube in a state where water is saturated in the water pipe and the outer surface of the conduit (B) is covered with soil containing moisture. When it is, the extra water contained in the soil can be taken into the porous tube (suction) and sent to the water storage tank.

  In the irrigation method according to the present invention, as described above, in a state where water is saturated in the water pipe and the outer surface of the conduit (B) is covered with soil containing moisture, the water oozes to the soil side by capillary action. Water is supplied to the plant roots. Usually, the position of the water surface in the water tank is maintained at the same position (horizontal position) as the position of the porous tube or at a low position. The low position in this case depends on the area of the soil to be irrigated, the type of plant grown and cultivated in the soil, the time of growth (eg, germination or growth period), the size of the water tank, etc. Although it can change suitably according to a condition, it is usually chosen in the range of 10-300 mm. The type of water is not limited as long as it is suitable for plant growth, such as rainwater, river water, groundwater, and tap water. In this case, nutrients necessary for the growth of plants such as fertilizer can be dissolved as necessary. Plants that can be grown and cultivated in soil are not particularly limited, and examples include various vegetables, flowers, fruits, and trees.

When the soil covering the outer surface of the conduit (B) runs out of water, the soil dries and shrinks and delaminates from the outer surface of the conduit (B). It becomes impossible to supply. In the irrigation method according to the present invention, for the purpose of preventing the soil from peeling from the outer surface of the conduit (B), slightly before the soil is detached from the outer surface of the conduit (B) (for example, about half a day to about 2 days). In addition, the position of the water surface in the water tank is intermittently slightly higher than the position (horizontal position) of the conduit (B) buried in the soil, and water is actively moved from the surface of the conduit (B) to the soil side. Let it exude. By doing in this way, it can prevent that a soil peels from the outer surface of a conduit | pipe (B), and can maintain a capillary phenomenon. Slightly higher refers to the soil environment (region, field or greenhouse, soil type, etc.), the area of the soil to be irrigated, the type of plants grown and cultivated in the soil, and the time of growth (emergence or growth phase) Etc.), depending on the size of the water storage tank, etc., and can be changed as appropriate depending on the situation. By making the position slightly higher, a slight positive pressure of about 0.003 to 0.005 kg / cm ² can be obtained.

  As a specific method of intermittently supplying water into the water tank and setting the position of the water surface in the water tank slightly higher than the position of the porous pipe embedded in the soil, (1) In the water tank (2) A method for supplying water at regular intervals by a timer, (3) A method for detecting the soil moisture concentration on the outer surface of the porous tube with a detection device, and supplying water. Etc.

  In the method (1), a water level detector is installed in the water tank. The water level detection device consists of a mechanism that detects the level of the water surface with a water surface sensor and sends a signal to the switch of the electromagnetic valve for water supply when it reaches any of the set positions. Are preferred. The water surface detection sensor may be composed of a pair of sensors that detect a low water level and a high water level (see FIG. 1 described later). When the water level of the water storage tank becomes lower than the set position, the water supply valve is opened to supply water to the water storage tank, and when the water level reaches the set position, the water supply valve is set to close. As the water surface detection sensor, an appropriate sensor can be selected from various commercially available float switches. Another method of the above (1) includes a method of detecting a low water level and a high water level with a floating ball arranged in the water tank, and opening and closing a ball tap valve to supply water to the water tank.

  When the water supply from the ball tap valve in the other method of (1) above is insufficient for the method of supplying water at regular intervals by the timer of (2) above, an automatic irrigation timer is additionally provided to set the time In addition, the set amount of water can be supplied for a set time. Appropriate water supply time, supply time and supply amount, etc. are determined by the area where the soil is located, the nature of the soil, the area of the soil to be irrigated, the type of plants grown and cultivated in the soil, and the time of growth ( It depends on the soil environment such as germination period or growth period), the size of the water tank, etc., and can be determined by experience and prior experiments depending on the situation. As the automatic irrigation timer, an appropriate one can be selected from various commercially available products.

  In the above (3), a moisture concentration detection sensor for detecting the moisture concentration of the coated soil is buried in the outer surface covered soil of the porous tube buried in the soil, thereby detecting the soil moisture concentration, and below the set concentration It is preferable to use a mechanism that sends a signal to the switch of the electromagnetic valve for water supply when it becomes, and opens the electromagnetic valve to supply water for a certain time. The moisture concentration at which the switch is activated and the water supply time can be determined by prior experimentation and experience. As the soil moisture concentration detection sensor, an appropriate sensor can be selected from various commercially available moisture concentration detection sensors.

Hereinafter, the present invention will be described in detail with reference to the drawings. However, the method of the present invention is not limited to the examples described below. FIG. 1 is a schematic view showing an example of carrying out the method of the present invention. In FIG. 1, 1 is a water pipe, 2 is a water storage tank, 3 is plant cultivation soil, 4 is a plant, 5 and 6 are conduits, 7 is a porous pipe, 8 is water, 9 is a horizontal position of the porous pipe, 10 , 11 is a water surface sensor, 10 ′ is the tip position of the lower limit sensor, 11 ′ is the tip position of the upper limit sensor, 12 is a switch of the solenoid valve, and 13 is a solenoid valve. In FIG. 1, a water pipe is formed by connecting a porous pipe 7 having a pore on the wall surface to an appropriate position of a water-permeable conduit 5 having no pore on the wall surface. It is buried in. Both ends of the water supply pipe are connected to the water storage tank 2 by conduits 5 and 6 at a position lower than the horizontal position 9 of the porous pipe 7. In the water tank 2, water 8 is maintained at the same position or a low position as the horizontal position 9 of the porous pipe 7, and the water supply pipe is saturated with the water 8 from the water tank 2. In order to saturate the water 8 in the water pipe, water may be supplied into the water pipe at a pressure of about ² to 3 kg / cm ² and filled while forcibly removing the air.

  Even if the water level in the water tank 2 is lower than the horizontal position 9 of the porous tube 7, the water 8 saturated in the water pipe may remain in the water pipe due to the siphon effect and fall into the water tank 2 as described above. And the saturated state in the water pipe is maintained. When the moisture pressure of the soil 4 in contact with the surface of the porous tube 7 is (b) and the moisture pressure of the porous tube 7 is (a), when (a)> (b), the porous tube 7 7 can be exuded to the soil 4 side from the pores, and water can be supplied to the plants grown and cultivated in the soil 4. When (a) <(b), moisture contained in the soil 4 can be taken into the porous tube 7 (suction), and moisture / humidity in the soil 4 can be adjusted.

  When the water level of the water storage tank 2 falls, in the example shown in FIG. 1, the level of the water level is detected by the pair of water level detection sensors 10 and 11. The lower limit position 10 ′ of the water surface is detected at the tip of the lower limit sensor 10, an ON signal is sent from the switch 12 to the electromagnetic valve 13, the electromagnetic valve 13 is opened, and water is supplied to the water storage tank 2. The upper limit position 11 ′ of the water surface is detected by the tip of the upper limit sensor 11, an OFF signal is sent from the switch 12 to the electromagnetic valve 13, the electromagnetic valve 13 is closed, and the supply of water to the water storage tank 2 is stopped. By doing in this way, the water surface of the water 8 in the water tank 2 can be adjusted to a narrow range across the horizontal position 9 of the porous tube 7. The lower limit position 10 ′ of the lower limit sensor and the upper limit position 11 ′ of the upper limit sensor can be determined by prior experiments and experience, and the horizontal position 9 of the porous tube 7 is sandwiched depending on the size of the water tank 2. Is selected in the range of +50 mm to −300 mm. The water surface sensor may be a float switch as described above.

FIG. 2 is a schematic view showing another example of carrying out the method of the present invention. In FIG. 2, 21 is a water pipe, 22 is a water storage tank, 23 is plant cultivation soil, 24 is a plant, 25 and 26 are conduits, 27 is a porous pipe, 28 is water, 30 is a floating ball, 31 is a ball tap valve, 32 is a ball tap valve support, and 33 is an automatic irrigation timer. In FIG. 2, a water pipe is formed by connecting a porous pipe 27 having a pore on the wall surface to an appropriate location of a conduit 25 that has no pores on the wall surface. It is buried inside. Both ends of the water supply pipe are connected to the water storage tank 22 at lower positions than the porous pipe 27 by conduits 25 and 26. Water 28 is maintained in the water tank 22 at the same position as the horizontal position of the porous tube 27 or at a low position, and the water supply pipe is saturated with the water 28 from the water tank 22. In order to saturate the water 28 in the water pipe, water may be supplied into the water pipe at a pressure of about ² to 3 kg / cm ² and filled while forcibly removing the air.

  In the example shown in FIG. 2, the water level in the water storage tank 22 is normally set so that the floating ball 30 and the ball tap valve 31 are always kept constant in conjunction with each other. However, since the external environment (outside air temperature, humidity, etc.) may change drastically, soil drying and soil shrinkage may occur, so an automatic irrigation timer 33 is provided for the purpose of responding to such a sudden change in the external environment. It is preferable to do this. The automatic irrigation timer 33 is connected to the water pipe 21 and can supply the set amount of water at the set time for the set number of times and the set time. As described above, the irrigation time by the automatic irrigation timer 33, the number of irrigation per day, the irrigation time per time, the irrigation amount, etc. can be determined by experience or prior experiments.

  The method of the present invention is as described above in detail, in addition to fields and greenhouses with various areas, soil on the roof of buildings, pot plants with a small area (pot plants for plant cultivation for greening the walls of buildings) And soil of planters that grow and cultivate plants.

1, 2: 1: Water pipe 2, 22: Water tank 3, 23: Plant cultivation soil 4, 24: Plant 5, 6, 25, 26: Conduit 7, 27: Porous pipe
8, 28: Water 9: Horizontal position of porous tube 10, 11: Water surface lower limit sensor 10 ': Water surface lower limit position 11': Water surface upper limit position 12: Switch of solenoid valve 13: Solenoid valve 30: Floating ball 31: Ball tap Valve 32: Ball tap valve support 33: Automatic watering timer

Claims (5)

  A plurality of porous pipes with pores on the wall surface are placed at appropriate locations on a conduit that does not have pores on the wall surface, and a connected water pipe is buried in the soil. Both ends of the water tank are connected to the water storage tank below the position of the porous pipe, and the water surface of the water storage tank is normally maintained at the same position (horizontal position) or low as the porous pipe. When the water pressure in the porous tube is (a) and the water pressure contained in the soil in contact with the surface of the porous tube is (b), when (a)> (b) In the irrigation method using the water pressure difference in which the moisture in the tube is leached to the soil side, and when (a) <(b), the moisture contained in the soil is taken into (sucked into) the porous tube, The position of a porous tube that supplies water into the reservoir and places the surface of the water in the reservoir in the soil It was slightly higher position than, characterized in that the water pressure in the water tank into a fine positive pressure, irrigation method into the soil using a pressure difference.   The method for irrigating soil using a water pressure difference according to claim 1, wherein the conduit is made of a thermoplastic synthetic resin and has an inner diameter of 1 to 50 mm and a wall thickness of 0.5 to 20 mm.   The porous tube has a pore diameter of 0.01 to 200 µm, an inner diameter of 5 to 50 mm, and a wall thickness of 0.5 to 30 mm, and is applied to the soil using the water pressure difference according to claim 1 or 2. Irrigation method.   The method of irrigating soil using the water pressure difference according to any one of claims 1 to 3, wherein the position of the water surface in the water tank is detected by a water level detection device.   5. The water level detection device according to claim 4, wherein the water level detection device is configured by a mechanism that detects a level of a water surface with a water surface detection sensor and instructs a switch of an electromagnetic valve for water supply to open and close the electromagnetic valve that supplies water. Irrigation method to soil using water pressure difference

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