JP2001305126A - Lysimeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lysimeter which is made to be handled easily by preventing the overflow, etc., of collected water. SOLUTION: This lysimeter which is buried in the ground (2) to collect water and used for the measurement of the quantity, physical property values, etc., of the collected water is provided with a water collecting means (water collecting section 4), sensors (electric conductivity sensor 24, pH sensor 26, temperature sensor 28, water level gauge 30, and water level sensor 34), draining means (a drain port 10, a pipe 12, and a solenoid valve 36), a returning means (reducing section 14), etc. This lysimeter, can prevent the overflow of the collected water from the water collecting means by making the collected water to be automatically discharged from the collecting means when the water level in the collecting means reaches a prescribed level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lysimeter which is installed in a field or the like and is used for monitoring the amount of fertilizer runoff.

[0002]

2. Description of the Related Art A lysimeter collects underground water and measures its components. The use of the lysimeter makes it possible to easily and automatically measure the amount of water (ie, soil water) and physical properties (electrical conductivity, ions, etc.) that move underground.

[0003]

The lysimeter has a tank for storing underground water, and this tank is buried by digging a field or the like. In addition, some conventional simple lysimeters pump water collected inside by a pump or the like, but there is a problem in that if the timing of the pumping is wrong, water overflows and it takes time to process.

[0004] Therefore, an object of the present invention is to provide a lysimeter which prevents the accumulated water from overflowing and is easy to handle.

[0005]

A lysimeter according to the present invention is a lysimeter buried underground (2) for storing water in the ground and used for measuring the amount of water, physical properties, and the like.
Water storage means (water storage unit 4), sensor (electric conductivity sensor 2)
4, pH sensor 26, temperature sensor 28, water level gauge 30, water level sensor 34), drainage means (drain port 10, pipe 12,
An electromagnetic valve 36) and a reducing means (reducing unit 14) are provided, and when the water level of the water storage means reaches a predetermined level, drainage is automatically enabled to prevent overflow from the water storage means.

The lysimeter of the present invention according to claim 1 is
A lysimeter that is buried in the ground to collect water in the ground, and is used for measuring the amount of water, physical properties, and the like.
Water storage means (water storage unit 4) buried in the ground to store underground water
A sensor (electrical conductivity sensor 24, pH sensor 26, temperature sensor 28, water level sensor 34, water level meter 30) installed in the water storage means and a water level of the water storage means at a predetermined level. It is characterized by having drainage means (drainage port 10, pipe 12, solenoid valve 36) for discharging water when it exceeds. That is, underground water flows into the water storage means buried underground, and the water is stored. The water stored in the water storage means comes into contact with a sensor installed in the water storage means, and the amount of water and physical properties are measured. Various physical properties such as electrical conductivity, pH, temperature, and ions exist. Therefore, a sensor corresponding to the physical property value to be measured is installed in the sensor. Then, when the water level of the water storage means exceeds a predetermined level, the water is drained from the drainage means and returned to the ground. Therefore, there is no overflow from the water storage means as in the prior art, and there is no need for time-consuming drainage, and the handling is simple.

According to a second aspect of the present invention, there is provided a reduction means (reduction unit 14) for reducing the wastewater from the drainage means into the ground. That is, the wastewater from the drainage means is returned to the ground through the reduction means.

The lysimeter of the present invention according to claim 3 is
The water storage means is provided with a filter (6) for selectively collecting only the water from the ground to collect water.
That is, a filter is provided in the water storage means, and only underground water (soil water) is selectively collected. Therefore, no contaminants such as soil settle in the water storage means, the occurrence of measurement errors can be prevented, and the maintenance and management thereof can be facilitated.

The lysimeter of the present invention according to claim 4 is
The water storage means is provided with a ventilation means (a ventilation pipe 9). That is, by allowing the water storage means to communicate with the outside air by the ventilation means, the internal pressure of the water storage means can be kept constant, and the water collecting function of the water storage means can be stabilized.

The lysimeter of the present invention according to claim 5 is
Water level detecting means (water level meter 3) for detecting the water level of the water storage means.
0, a water level sensor 34). That is, if the water level of the water storage means is detected, it is possible to grasp the amount of water moving underground and the measurement timing of the physical property value of water. And
When the predetermined level is reached, the drainage point can be clearly grasped.

The lysimeter of the present invention according to claim 6 is
It is characterized in that a siphon (pipe 12) for connecting the bottom of the water storage means and the reduction means to the drainage means and draining when the water level of the water storage means exceeds a predetermined level. That is, if a siphon is used, the water level of the water storage means can be maintained at a predetermined level set by the siphon without requiring a complicated drainage mechanism.

The lysimeter of the present invention according to claim 7 is
A filter (2) that allows only the water to pass through the reducing means.
0) is installed. That is, since only water is passed by the filter, the water in the water storage means can be returned to the ground from the reduction means.

The lysimeter of the present invention according to claim 8 is
The reduction means is provided with a ventilation means (a ventilation pipe 22). That is, by allowing the reducing means to communicate with the outside air through the ventilation means, the internal pressure of the reducing means can be kept constant, and the drainage function of the reducing means can be stabilized.

The lysimeter of the present invention according to claim 9 is:
An electromagnetic valve is provided in the water storage means, and when the water level of the water storage means exceeds a predetermined level, the electromagnetic valve is opened to drain water. That is, an electromagnetic valve for adjusting drainage is installed in the water storage means, closed in a normal state, and opened when the water level of the water storage means exceeds a predetermined level, so that the water level of the water storage means can be maintained at a predetermined level or less, and the water overflows. Can be prevented.

According to a tenth aspect of the present invention, the lysimeter according to the present invention is provided with water intake guide means on the upper side of the water storage means, and increases the water intake area of the water intake guide means at the same or any ratio as the diameter cross-sectional area of the water storage means. Alternatively, it is characterized by being set small. That is, if the water intake guide means is provided on the upper side of the water storage means, and the water intake area of the water intake guide means is larger than the diameter cross-sectional area of the water storage means, the water intake time when the water content is small can be shortened, Is smaller than the diameter cross-sectional area of the water storage means, the speed of the water intake time when the amount of water is large can be suppressed. Then, by setting the size of both to an optimal ratio, the amount of water flowing into the water storage means can be apparently adjusted.

An eleventh aspect of the present invention is the lysimeter according to the present invention, wherein each of the water storage means and the reduction means has the same or arbitrary ratio in the sectional area or height or volume of the reducing means. That is, if the diameter sectional areas or the heights or volumes of the water storage means and the reduction means are set to the same or different ratios in accordance with the characteristics of the soil, efficient measurement can be performed.

[0017]

FIG. 1 shows a lysimeter according to a first embodiment of the present invention. This lysimeter is provided with a water storage unit 4 as a water storage means for temporarily storing water in order to measure the physical property value and flow rate of water (soil water) moving underground 2, that is, soil. The part 4 is a bottomed cylindrical body formed of a water-resistant member, and its bottom surface is formed in a mortar shape. A filter 6 also serving as a lid is provided on the upper side of the water storage section 4, and the filter 6 is used to operate the water storage section 4.
Forms a closed space underground 2. The filter 6 is a means for blocking the soil and selectively passing only the water 8. Also,
The reason why the bottom of the water storage unit 4 is formed in a mortar shape is to facilitate drainage.

On the upper side of the water storage section 4, a ventilation pipe 9 is provided as ventilation means, and the other end of the ventilation pipe 9 is guided from the underground 2 to the ground and is open to the outside air. That is, since the internal pressure of the water storage unit 4 is open to the outside air, the water 8 is not restricted without entering the water storage unit 4.
Can be stabilized. The ventilation pipe 9 may be provided with a filter as a means for preventing intrusion of dust.

A drain port 10 is formed on the bottom of the water storage section 4 as a drain means. One end of a pipe 12 is connected to the drain port 10 as a drain means. Reduction unit 14 as reduction means for reducing to
It is attached to the upper side of. The curved portion 16 is formed by arranging the middle portion of the pipe 12 in parallel with the water storage portion 4 and bending the pipe 12 into a U-shape. The pipe 12 forms a siphon, and has a predetermined level L
e is set by the height of the bending portion 16. That is,
When the water level in the water storage unit 4 exceeds the predetermined level Le, the water 8 is passed through the pipe 12 as shown by arrows A and B,
Drained to the side.

The reducing section 14 is means for temporarily storing the water 8 drained from the water storage section 4 and returning the water 8 to the underground 2. A filter 20 that blocks soil and the like and allows only the water 8 to pass easily is installed in the reducing unit 14. A ventilation pipe 22 is provided on the upper side of the reducing section 14 as ventilation means. The other end of the ventilation pipe 22 is guided from the underground 2 to the ground and is open to the outside air. That is, since the internal pressure of the reduction unit 14 is open to the outside air, the drainage to the reduction unit 14 is not restricted and the drainage is stabilized. The ventilation pipe 22 may be provided with a filter as a means for preventing intrusion of dust.

Various sensors are installed in the water storage section 4 as means for measuring the physical property value and flow rate of the water 8 moving in the soil. In this embodiment, the electric conductivity sensor 2 is used.
4. A water level gauge 30 is installed as a means for measuring the flow rate, such as a pH sensor 26, a temperature sensor 28 and the like. Water level meter 3
The installation purpose of 0 is a means for measuring the water amount and the measurement timing, and since the pipe 12 constituting the siphon is installed, in this case, the water level control is performed by the siphon,
The water level gauge 30 as a means for obtaining the control information becomes unnecessary and may be omitted. And each of these sensors 2
The detection outputs of 4-28 and the water level gauge 30 are applied to a control unit 32 constituted by an electronic circuit or a sequence circuit as a control means, a computer, or the like. The control unit 32 is a means for calculating and processing a measured value, and the measured value can be displayed on a display (not shown) or printed.

The operation of the lysimeter will be described. In the water storage section 4, only the water 8 in the underground 2 flows through the filter 6 which also serves as a lid, and only the water 8 invades the water storage section 4.
The air inside is released from the ventilation pipe 9 to the outside air. The water 8 that has flowed into the water storage unit 4 accumulates up to a predetermined water level, that is, a predetermined level Le by a siphon formed of the pipe 12.

When the water level becomes equal to or higher than the predetermined level Le according to the siphon principle, the water 8 is discharged to the reducing section 14 until the water storage section 4 becomes empty. In this embodiment, the water level gauge 30 can detect that the sensors 24 to 28 installed in the water storage unit 4 have reached the water level at which they work effectively.

In the reducing section 14, since the water 8 discharged from the water storage section 4 does not immediately penetrate into the soil, the water 8
Is temporarily stored and gradually returned to the underground 2. At this time, even if a large amount of water 8 temporarily enters due to the air bleeding of the ventilation pipe 22, the drainage capacity of the pipe 12 as the drainage means is not affected.

In the control unit 32, the water level gauge 30 can detect that the sensors 24 to 28 installed in the water storage unit 4 are at or above the effective water level, and measure the water 8 in that case. In addition, the water level meter 30 can recognize whether the water storage unit 4 is full or empty from the time measurement by the timer and the water level at the timing of whether or not the water can be detected by the drainage by the pipe 12, and the change and the timer indicate the water 8, that is, the water 8. And the flow rate of soil water can be measured.

Next, the measurement control will be described. FIG. 2 shows the control algorithm. In the initial state, the water 8 is not in the water storage unit 4. In this case, the continuous water level of the water storage unit 4 is detected in the water level meter 30, and the measured water levels h0, h1, and h2 (h0 <h1 <h2) are set. In step S1, the detected water level from the water level gauge 30 is fetched, and it is determined whether or not the water level is equal to or lower than the measured water level h0. When the measured water level becomes equal to or higher than h0, step S2 is performed.
Then, the physical property value at the measurement water level h0 is measured. In this measurement, the physical properties of the water 8 are measured from detection outputs of the electric conductivity sensor 24, the pH sensor 26, the temperature sensor 28, and the like.

After this measurement, it is determined in step S3 whether the measured water level is equal to or lower than h1. When the measured water level is equal to or higher than h1, the process proceeds to step S4, and the physical property value is measured at the measured water level h1. In this measurement, the electric conductivity sensor 24, p
A physical property value of the water 8 is measured from detection outputs of the H sensor 26, the temperature sensor 28, and the like.

After the measurement, it is determined in step S5 whether or not the measured water level is equal to or lower than h2. When the measured water level is equal to or higher than h2, the process proceeds to step S6, and the physical property value is measured at the measured water level h2. In this measurement, the electric conductivity sensor 2
4. Measure physical properties of the water 8 from detection outputs of the pH sensor 26, the temperature sensor 28, and the like.

Next, in step S7, it is determined whether or not the measured water level is 0. If the measured water level is 0, the flow proceeds to step S8, where the flow rate is counted, and the flow returns to step S1. Then, when the water level exceeds the predetermined level Le, the water 8 in the water storage unit 4 is returned to the reduction unit 14 through the pipe 12 constituting the siphon.
And is returned to the underground 2 through the reduction unit 14.

Next, FIG. 3 shows a second embodiment of the lysimeter of the present invention. In this embodiment, a water level sensor 34 as a water level detection means is installed in the middle of the pipe 12 constituting the siphon, the water level of the water storage section 4 is detected through the pipe 12, and the detection output is input to the control section 32. It was made. In this case, the water level sensor 34 as means for obtaining water level information for drainage control is unnecessary, but if the water level sensor 34 is installed, it is higher than the water level at which the sensors 24 to 28 installed in the water storage section 4 work effectively. Can be used to detect that

The measurement control will be described. FIG.
The control algorithm is shown, and the water 8 is not in the water storage unit 4 in the initial state. Step S1
In step 1, the detected water level from the water level sensor 34 is fetched, and it is determined whether or not the water level is equal to or lower than the measured water level. If the measured water level is equal to or higher than the measured water level, the process proceeds to step S12 to measure physical property values. In this measurement, the physical properties of the water 8 are measured from detection outputs of the electric conductivity sensor 24, the pH sensor 26, the temperature sensor 28, and the like. In this case, the number of the water level sensors 34 may be plural, and in that case, the control is performed as shown in the flowchart of FIG.

After this measurement, it is determined in step S13 whether or not the measured water level is lower than the measured water level. If the measured water level is lower than the measured water level, the flow proceeds to step S14 to count the flow rate.
Return to 11. Then, when the water level exceeds a predetermined level Le, the water reservoir 4 through the pipe 12 constituting the siphon.
The water 8 is drained to the reduction unit 14 and returned to the underground 2 through the reduction unit 14.

Next, FIG. 5 shows a third embodiment of the lysimeter of the present invention. In this embodiment, a solenoid valve 36 for opening and closing the drain port 10 is provided as a drain unit,
The opening and closing of the solenoid valve 36 is opened and closed by the control unit 32 as control means under certain conditions. In this case, since the drainage control is performed by the electromagnetic valve 36, the measured value of the water level gauge 30 is used as the water level information.

The control operation will be described. FIG.
The control algorithm is shown, and the water 8 is not in the water storage unit 4 in the initial state. Step S2
In step 1, the detected water level from the water level gauge 30 is fetched, and it is determined whether the water level is equal to or lower than the measured water level. If the measured water level is equal to or higher than the measured water level, the process proceeds to step S22 to measure physical property values. In this measurement, the electric conductivity sensor 24, the pH sensor 26,
The physical property value of the water 8 is measured from the detection output of the temperature sensor 28 and the like.

After this measurement, in step S23, the flow rate is counted, and the solenoid valve 36 is opened to drain water. The water 8 in the water storage section 4 moves to the reduction section 14 and is returned to the underground 2 through the reduction section 14.

In step S24, after waiting for a predetermined time, that is, after the time required for drainage has elapsed, step S25 is performed.
Then, the electromagnetic valve 36 is closed, and the process returns to step S21.

FIG. 7 shows a lysimeter according to a fourth embodiment of the present invention. In this embodiment, a pipe 38 is connected to the bottom side of the water storage unit 4, and the pipe 38 is guided to the ground to be connected to a water level gauge 40 as a water level detection unit, so that the water level of the water storage unit 4 can be visually checked. Things. That is, the pipe 38 of the water level gauge 40 is bent into an N-shape and a scale plate 42 is also provided. Water 44 is contained in the pipe 38, and the movement amount of the trapped air 46 is reduced by the water 44. Is displayed as the movement of the end of. This display value indicates the water level.

Further, a vent pipe 9 is connected to the water storage section 4 to open it to the outside air, and a drain pipe 48 is connected to the bottom side thereof, and the other end is guided to the ground.
Water 8 can be removed. If a pump (not shown) is connected to the pipe 48, the pump can be driven to drain the water 8 from the water storage unit 4 as needed or when the predetermined level Le is reached.

According to such a lysimeter, the level of the water 8 stored in the water storage section 4 can be visually recognized by the water level gauge 40, and the timing of pumping and the amount of stored water can be confirmed from the outside. Inconveniences such as flooding can be prevented.

FIG. 8 shows a lysimeter according to a fifth embodiment of the present invention. The amount of soil water flowing into the lysimeter varies greatly due to various factors such as soil and precipitation. In order to cope with such a factor, in this embodiment, a water intake guide section 50 as a funnel-shaped water intake guide means is provided above the water storage section 4. That is, the filter 6 is installed on the upper surface of the water intake guide section 50 to form a water intake surface, and if this water intake area is S ₁ ,
Diameter cross-sectional area S ₂ of the same or any ratio of the water storage unit 4 (S ₂
/ S ₁ = N).

In the underground 2 where the lysimeter is installed, it takes time to reach a measurable water level, that is, a water intake time, in a place where soil water is small, and the number of times of measurement is reduced. If S ₁ > S ₂ , for example, S ₁ = 2S ₂ , then 2
Soil water accumulates in the water storage unit 4 at twice the speed, so that the water intake time or the measurement time can be shortened, and the number of measurements can be increased.

FIG. 9 shows a lysimeter of the present invention.
6 shows the sixth embodiment. Soil flowing into lysimeter
The amount of loin water varies greatly due to various factors such as soil and precipitation.
Therefore, in this embodiment, in order to respond to the factor,
Water intake guide means formed in an inverted funnel shape on the upper part of the water storage part 4;
The water intake guide part 52 is installed. That is,
The filter 6 is installed on the upper surface of the water intake guide part 52 to take water.
And the intake area is S₁Then, water storage
Diameter cross section S of part 4_TwoAnd any ratio (S_Two/ S ₁= 1 /
N) to set small.

In the underground 2 where the lysimeter is installed, the time required to reach a measurable water level becomes short in a place where there is a lot of soil water. For example, if S ₂ / S ₁ = １ ／, it takes 2 minutes. Soil water accumulates in the water storage section 4 at the speed of 1 and the water intake time can be suppressed.

As shown in the fifth and sixth embodiments,
By setting S ₁ and S ₂ to an optimal ratio, the flow rate of soil water flowing into the water storage unit 4 can be apparently adjusted.

Next, another embodiment of the present invention will be described. The shape of the water storage section 4 does not need to be cylindrical, and the bottom does not need to be an inverted conical shape, and the level of the drain port for drainage may be lower than the other.

If there is an open space outside each sensor installation position, the reducing section 14 can be omitted by directly guiding the ventilation pipe 22 to the open space. Further, it is not necessary to install the reduction unit 14 below the water storage unit 4. For example, if there is a well-drained soil nearby, it may be installed there. Further, the size can be arbitrarily set according to the flow rate of the soil water.

The control unit 32 may be buried in the ground, or may be installed at a place visible on the surface of the ground.
When installed on the surface of the earth, it is possible to provide a function of displaying measured values. Further, if a data transfer function is provided, data can be transferred to a computer by wire or wireless (including a telephone line and a mobile phone), and the detected data can be effectively used.

The diameter cross-sectional area or the height or volume of each of the water storage section 4 and the reduction section 14 may be set to the same or any ratio. That is, if the diameter cross-sectional areas or the heights or volumes of the water storage unit 4 and the reduction unit 14 are set to the same or different ratios in accordance with the characteristics of the soil, efficient measurement can be performed.

[0049]

As described above, according to the present invention,
The amount of water that moves in the ground can be measured by a sensor, and the amount and physical properties (electrical conductivity, ions, etc.) can be easily and automatically measured.
For example, it can be drained by the principle of siphon,
The setting of the water level can be easily changed by changing the height of the upper part of the pipe, and the water can be easily drained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a lysimeter of the present invention.

FIG. 2 is a flowchart illustrating a control algorithm.

FIG. 3 is a diagram showing a lysimeter according to a second embodiment of the present invention.

FIG. 4 is a flowchart illustrating a control algorithm.

FIG. 5 is a diagram showing a third embodiment of the lysimeter of the present invention.

FIG. 6 is a flowchart illustrating a control algorithm.

FIG. 7 is a diagram showing a lysimeter according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a fifth embodiment of the lysimeter of the present invention.

FIG. 9 is a diagram showing a lysimeter according to a sixth embodiment of the present invention.

[Explanation of symbols]

 2 Underground 4 Water storage unit (water storage unit) 6 Filter 9 Ventilation pipe (ventilation unit) 10 Drain outlet (drainage unit) 12 Pipe (drainage unit, siphon) 14 Reduction unit (reduction unit) 20 Filter 22 Ventilation pipe (ventilation unit) 24 Electric conductivity sensor 26 pH sensor 28 Temperature sensor 30 Water level gauge (water level detecting means) 34 Water level sensor (water level detecting means) 36 Solenoid valve (draining means)

Claims (11)

[Claims] 1. A lysimeter buried in the ground to store underground water and used for measuring the amount of water, physical properties, and the like, and a water storage means buried in the ground to store underground water; A lysimeter comprising: a detecting means installed in the water storage means for detecting characteristics of water; and a drainage means for discharging water when the water level of the water storage means exceeds a predetermined level. 2. The lysimeter according to claim 1, further comprising a reduction means for reducing wastewater from said drainage means into the ground. 3. The lysimeter according to claim 1, wherein a filter for selectively collecting only the water from the underground and collecting water is provided in the water storage means. 4. The lysimeter according to claim 1, wherein said water storage means is provided with a ventilation means. 5. The lysimeter according to claim 1, further comprising a water level detection means for detecting a water level of said water storage means. 6. A siphon that connects the bottom of the water storage means and the reduction means and drains when the water level of the water storage means exceeds a predetermined level is used as the drainage means. The lysimeter according to claim 1. 7. The lysimeter according to claim 1, wherein a filter that allows only the water to pass is provided in the reducing unit. 8. The lysimeter according to claim 1, wherein said reducing means includes a ventilation means. 9. The lysimeter according to claim 1, wherein the water storage means is provided with an electromagnetic valve, and when the water level of the water storage means exceeds a predetermined level, the electromagnetic valve is opened to drain water. 10. A water intake guide means is provided on an upper side of the water storage means, and an intake area of the water intake guide means is set to be larger or smaller at the same or any ratio as the diameter cross-sectional area of the water storage means. The lysimeter according to claim 1. 11. The lysimeter according to claim 1, wherein each of the water storage means and the reduction means has the same or arbitrary ratio in the sectional area or height or volume of the reducing means.