CN116593500A - Soil water content detection system and method - Google Patents
Soil water content detection system and method Download PDFInfo
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- CN116593500A CN116593500A CN202310562914.6A CN202310562914A CN116593500A CN 116593500 A CN116593500 A CN 116593500A CN 202310562914 A CN202310562914 A CN 202310562914A CN 116593500 A CN116593500 A CN 116593500A
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- soil
- moisture content
- soil moisture
- probe
- reflected wave
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- 239000002689 soil Substances 0.000 title claims abstract description 148
- 238000000034 method Methods 0.000 title claims abstract description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 17
- 238000001514 detection method Methods 0.000 title claims description 37
- 239000000523 sample Substances 0.000 claims description 41
- 238000005070 sampling Methods 0.000 claims description 29
- 238000011088 calibration curve Methods 0.000 claims description 15
- 229910001220 stainless steel Inorganic materials 0.000 claims description 4
- 239000010935 stainless steel Substances 0.000 claims description 4
- 238000004806 packaging method and process Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 abstract description 10
- 238000012544 monitoring process Methods 0.000 description 5
- 238000002310 reflectometry Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000010413 gardening Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N22/00—Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more
- G01N22/04—Investigating moisture content
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
- G01N27/221—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance by investigating the dielectric properties
Abstract
The invention discloses a system and a method for detecting the water content of soil, which relate to the field of soil water content measurement. The method can rapidly and accurately measure the soil moisture content of the target soil, has small damage to the soil, and can realize repeated measurement of the same soil.
Description
Technical Field
The invention relates to the field of soil water content measurement, in particular to a soil water content detection system and method.
Background
The determination of the water content of soil is the basis of investigation and research in the environmental field, is the important point of developing agricultural, hydrologic and water conservancy researches, and is widely applied to the fields of agriculture, forestry, ecology, hydrologic, hydraulic engineering, gardening and the like at present. At present, the soil water content measuring method is more. The drying method is a common and direct method, but the method is time-consuming and labor-consuming, has a certain destructiveness to soil and cannot be used for repeatedly measuring the same soil. Neutron and Y-ray methods are widely used, but these two methods have the problem of inaccurate measurement.
Disclosure of Invention
The invention aims to provide a system and a method for detecting the water content of soil, so as to realize rapid and accurate determination of the water content of the soil.
In order to achieve the above object, the present invention provides the following solutions:
a soil moisture content detection system comprising:
an electromagnetic pulse emitter for generating a detection electromagnetic wave;
the probe is connected with the electromagnetic pulse emitter, inserted into target soil and used for transmitting the detection electromagnetic wave into the target soil;
the sampling oscilloscope is connected with the electromagnetic pulse transmitter and is used for determining the round trip time of the electromagnetic wave according to the first reflected wave and the second reflected wave; the first reflected wave is generated by reflection when the detection electromagnetic wave passes through the top end of the probe, and the second reflected wave is generated by reflection when the detection electromagnetic wave passes through the bottom end of the probe; the electromagnetic pulse transmitter is also used for receiving the first reflected wave and the second reflected wave and transmitting the first reflected wave and the second reflected wave to the sampling oscilloscope;
a processor for determining an apparent permittivity of the target soil according to the round trip time of the electromagnetic wave, and determining a soil moisture content of the target soil according to the apparent permittivity of the target soil and a soil moisture content calibration curve; the soil moisture content calibration curve is obtained by performing linear fitting on the apparent dielectric constants of the soil with a plurality of sampling points and the soil moisture content of the soil with the sampling points.
Optionally, the method further comprises:
and the cable is used for connecting the probe and the electromagnetic pulse emitter.
Optionally, the method further comprises:
and the power supply is respectively connected with the electromagnetic pulse emitter, the sampling oscilloscope and the processor and is used for supplying power to the electromagnetic pulse emitter, the sampling oscilloscope and the processor.
Optionally, the method further comprises:
and the shell is used for packaging the electromagnetic pulse emitter, the sampling oscilloscope and the processor.
Optionally, the probe is made of stainless steel.
Optionally, the length of the probe is 50 mm-80 mm.
Optionally, the measurement temperature of the probe is-40-100 ℃; the measuring range of the probe is 0-100% of volume water content.
Alternatively, the power source is a 24V 12a battery or 220V ac.
The soil moisture content detection method is applied to the soil moisture content detection system and comprises the following steps:
transmitting a detection electromagnetic wave to the target soil and receiving the first reflected wave and the second reflected wave;
determining a round trip time of an electromagnetic wave from the first reflected wave and the second reflected wave;
determining the apparent dielectric constant of the target soil according to the round trip time of the electromagnetic wave;
and determining the soil moisture content of the target soil according to the apparent dielectric constant of the target soil and the soil moisture content calibration curve.
Optionally, determining the apparent dielectric constant of the target soil according to the round trip time of the electromagnetic wave, wherein the specific formula is as follows:
wherein K is α The apparent dielectric coefficient of the target soil; t is the round trip time of the electromagnetic wave; l is the length of the probe; c is the propagation speed of the electromagnetic wave in vacuum.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
according to the soil moisture content detection system provided by the invention, the electromagnetic pulse emitter is utilized to generate the detection electromagnetic wave, the detection electromagnetic wave is transmitted to the target soil by the probe, as the electromagnetic wave is transmitted, a part of the electromagnetic wave is reflected back when transmitted to the top end of the probe due to the difference of the impedance of the cable and the probe, and the rest of the electromagnetic wave is reflected back when reaching the bottom end of the probe, so that the round trip time of the electromagnetic wave can be determined by the sampling oscilloscope according to the first reflected wave and the second reflected wave, the apparent dielectric constant of the target soil can be determined by the processor according to the round trip time of the electromagnetic wave, and the soil moisture content of the target soil can be determined according to the apparent dielectric constant of the target soil and the soil moisture content calibration curve. The method can rapidly and accurately measure the soil moisture content of the target soil based on the Time domain reflectometry (Time-Domain Reflectometry, TDR) technology, has small damage to the soil, and can realize repeated measurement of the same soil.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a block diagram of a soil moisture content detection system provided by the present invention;
fig. 2 is a flowchart of a method for detecting soil moisture content provided by the invention.
Symbol description:
electromagnetic pulse emitter-1, sampling oscilloscope-2, probe-3, cable-4, shell-5.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a system and a method for detecting the water content of soil, so as to realize rapid and accurate determination of the water content of the soil.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
As shown in fig. 1, the soil moisture content detection system provided by the present invention includes: an electromagnetic pulse emitter 1, a probe 3, a sampling oscilloscope 2 and a processor. Wherein, electromagnetic pulse transmitter 1, sampling oscilloscope 2 and treater constitute soil moisture content appearance.
Specifically, the electromagnetic pulse emitter 1 is used for generating a detection electromagnetic wave. The probe 3 is connected to the electromagnetic pulse emitter and inserted into the target soil for transmitting the detected electromagnetic wave into the target soil. Preferably, the frequency of the detected electromagnetic wave is 0.5 GHz-1.5 GHz.
As a specific embodiment, a stainless steel probe is inserted into the target soil. Wherein the probe length is about 50 mm-80 mm; the stainless steel material is adopted, so that the probe is required to be prevented from being corroded when the probe works in a region with high salt content in soil; the measuring range of the probe should be kept at 0-100% of the volume water content; the probe measurement temperature should be kept at-40 to +100 ℃; therefore, the soil moisture content measuring system provided by the invention has higher soil volume moisture content measuring precision and resolution.
In the present embodiment, the probe 3 is used as an induction sensor for detecting soil data inserted into the soil, and the requirement of continuous monitoring is satisfied by temporarily or chronically burying the probe 3 in the soil and connecting it to a soil moisture meter. The soil moisture content meter adopts a TDR technology, calculates the apparent dielectric constant of the soil by monitoring the propagation time of electromagnetic pulse signals in the soil, and calculates the soil moisture content according to the content of each component of the soil and the relation between the dielectric constants.
The sampling oscilloscope 2 is connected with the electromagnetic pulse transmitter and is used for determining the round trip time of electromagnetic waves according to the first reflected wave and the second reflected wave; since a part of electromagnetic waves are reflected back when transmitted to the top end of the probe due to different impedance of the cable and the probe, and the rest of electromagnetic waves are reflected back when reaching the bottom through the probe, the first reflected wave is generated by reflection when the detected electromagnetic waves pass through the top end of the probe, and the second reflected wave is generated by reflection when the detected electromagnetic waves pass through the bottom end of the probe; the electromagnetic pulse transmitter is also used for receiving the first reflected wave and the second reflected wave and transmitting the first reflected wave and the second reflected wave to the sampling oscilloscope.
Specifically, the sampling oscilloscope 2 is composed of a tube amplifier, a scan oscillator, a cathode ray tube, and the like as an instrument for measuring the shape of alternating current or pulse current wave. The sampling oscilloscope 2 can sample in the electromagnetic wave transmission process to obtain a voltage/amplitude time/distance variation value, and further determine the round trip time t of the electromagnetic wave reflected from the top end to the bottom end of the probe.
The processor is used for determining the apparent dielectric constant of the target soil according to the round trip time of the electromagnetic wave and determining the soil moisture content of the target soil according to the apparent dielectric constant of the target soil and a soil moisture content calibration curve; the soil moisture content calibration curve is obtained by performing linear fitting on the apparent dielectric constants of the soil with a plurality of sampling points and the soil moisture content of the soil with the sampling points.
As a specific embodiment, the present invention uses TDR monitoring techniques to determine the apparent permittivity of the target soil. The TDR monitoring technique is shown in the following formula:
by deforming the above formula, the specific formula for calculating the apparent dielectric constant of the target soil is as follows:
wherein K is α The apparent dielectric coefficient of the target soil; t is the round trip time of the electromagnetic wave; l is the length of the probe; c is the propagation speed of the electromagnetic wave in vacuum.
As a specific embodiment, the following factors are generally not considered in the soil moisture content detection process: bulk density, porosity, organic content, etc. The calculation of the soil moisture content is often to linearly fit the apparent dielectric constant of the sampling point soil measured by the TDR with the soil moisture content of the sampling point soil obtained by other methods (such as remote sensing technology, ground penetrating radar, field test, earth measurement, etc.), so as to obtain a soil moisture content calibration curve, and substituting the apparent dielectric constant of the target soil measured by the TDR into the soil moisture content calibration curve, so as to obtain the soil moisture content of the target soil.
The expression of the soil moisture content calibration curve is as follows:
wherein the coefficient alpha 0 ，α 1 ，α 2 ，α 3 Are fitting parameters and are related to soil texture and soil type. θ is the soil moisture content.
Further, the system further comprises: a cable 4; the cable 4 is used to connect the probe 3 and the electromagnetic pulse emitter 1.
Further, the system further comprises: a power supply; the power supply is respectively connected with the electromagnetic pulse emitter 1, the sampling oscilloscope 2 and the processor and is used for supplying power to the electromagnetic pulse emitter 1, the sampling oscilloscope 2 and the processor.
As a specific embodiment, the power source is a 24V 12a battery or 220V ac.
Further, the system further comprises: a housing 5; the housing 5 is used for packaging the electromagnetic pulse transmitter 1, the sampling oscilloscope 2 and the processor.
As a specific embodiment, the housing is compact, and can prevent the collision caused by gaps among the parts inside.
Further, the present invention also provides a soil moisture content detection method, which is applied to the above system, as shown in fig. 2, and includes:
step S1: the detection electromagnetic wave is emitted to the target soil and the first reflected wave and the second reflected wave are received.
Step S2: a round trip time of the electromagnetic wave is determined from the first reflected wave and the second reflected wave.
Step S3: and determining the apparent dielectric constant of the target soil according to the round trip time of the electromagnetic wave.
Step S4: and determining the soil moisture content of the target soil according to the apparent dielectric constant of the target soil and the soil moisture content calibration curve.
In summary, the soil moisture content detection system and method provided by the invention adopt one of the most extensive soil moisture content measurement methods, namely TDR technology, calculate the apparent dielectric constant of the soil by monitoring the propagation time of electromagnetic pulse signals in the soil, and then scientifically and reasonably determine a soil moisture content calibration curve (namely, the relationship between the apparent dielectric constant of the soil and the moisture content of the soil) according to the relationship fit of the dielectric constant and the content of each component of the soil, so that the soil moisture content of the target soil is calculated by utilizing the apparent dielectric constant of the soil moisture content calibration curve and the apparent dielectric constant of the target soil, and the soil moisture content can be rapidly, accurately and automatically measured indoors and outdoors. Compared with the prior art, the invention has the advantages of real-time measurement, no damage to soil and engineering, good accuracy and precision, high measurement speed and the like.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (10)
1. A soil moisture content detection system, comprising:
an electromagnetic pulse emitter for generating a detection electromagnetic wave;
the probe is connected with the electromagnetic pulse emitter, inserted into target soil and used for transmitting the detection electromagnetic wave into the target soil;
the sampling oscilloscope is connected with the electromagnetic pulse transmitter and is used for determining the round trip time of the electromagnetic wave according to the first reflected wave and the second reflected wave; the first reflected wave is generated by reflection when the detection electromagnetic wave passes through the top end of the probe, and the second reflected wave is generated by reflection when the detection electromagnetic wave passes through the bottom end of the probe; the electromagnetic pulse transmitter is also used for receiving the first reflected wave and the second reflected wave and transmitting the first reflected wave and the second reflected wave to the sampling oscilloscope;
a processor for determining an apparent permittivity of the target soil according to the round trip time of the electromagnetic wave, and determining a soil moisture content of the target soil according to the apparent permittivity of the target soil and a soil moisture content calibration curve; the soil moisture content calibration curve is obtained by performing linear fitting on the apparent dielectric constants of the soil with a plurality of sampling points and the soil moisture content of the soil with the sampling points.
2. The soil moisture content detection system of claim 1, further comprising:
and the cable is used for connecting the probe and the electromagnetic pulse emitter.
3. The soil moisture content detection system of claim 1, further comprising:
and the power supply is respectively connected with the electromagnetic pulse emitter, the sampling oscilloscope and the processor and is used for supplying power to the electromagnetic pulse emitter, the sampling oscilloscope and the processor.
4. The soil moisture content detection system of claim 1, further comprising:
and the shell is used for packaging the electromagnetic pulse emitter, the sampling oscilloscope and the processor.
5. The soil moisture content detection system of claim 1, wherein the probe is stainless steel.
6. The soil moisture content detection system of claim 1, wherein the probe has a length of 50mm to 80mm.
7. The soil moisture content detection system of claim 1, wherein the probe has a measured temperature of-40 ℃ to 100 ℃; the measuring range of the probe is 0-100% of volume water content.
8. A soil moisture content detection system according to claim 3 wherein the power source is a 24V 12a battery or 220V ac.
9. A soil moisture content detection method, characterized in that the soil moisture content detection method is applied to the soil moisture content detection system according to any one of claims 1 to 8, comprising:
transmitting a detection electromagnetic wave to the target soil and receiving the first reflected wave and the second reflected wave;
determining a round trip time of an electromagnetic wave from the first reflected wave and the second reflected wave;
determining the apparent dielectric constant of the target soil according to the round trip time of the electromagnetic wave;
and determining the soil moisture content of the target soil according to the apparent dielectric constant of the target soil and the soil moisture content calibration curve.
10. The method for detecting the water content of soil according to claim 9, wherein the apparent permittivity of the target soil is determined according to the round trip time of the electromagnetic wave, and the specific formula is:
wherein K is α The apparent dielectric coefficient of the target soil; t is the round trip time of the electromagnetic wave; l is the length of the probe; c is the propagation speed of the electromagnetic wave in vacuum.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202310562914.6A CN116593500A (en) | 2023-05-18 | 2023-05-18 | Soil water content detection system and method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310562914.6A CN116593500A (en) | 2023-05-18 | 2023-05-18 | Soil water content detection system and method |
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| CN116593500A true CN116593500A (en) | 2023-08-15 |
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| CN202310562914.6A Pending CN116593500A (en) | 2023-05-18 | 2023-05-18 | Soil water content detection system and method |
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- 2023-05-18 CN CN202310562914.6A patent/CN116593500A/en active Pending
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