JP2012242127A - Soil sensor and soil sensing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply determine the properties of soil.SOLUTION: A soil sensor includes first electrodes 12 to be in direct contact with soil 28, a reference material 16 with water permeability and water retentivity, second electrodes 14 to be in contact with the soil 28 through the reference material 16, and a determination unit 36 that determines properties of the soil 28 on the basis of permittivity of the soil 28 measured using the first electrodes 12 and permittivity of the reference material 16 measured using the second electrodes 14.

Description

  The present invention relates to a soil sensor and a soil sensing method, for example, a soil sensor and a soil sensing method for determining soil quality by measuring the dielectric constant of soil.

  For example, for the purpose of disaster prevention, it is considered effective to measure the amount of water in the soil in order to quickly detect and predict levee breaks and sediment disasters such as rivers and dams. For example, if the amount of water in the soil can be measured in time series, the state of water penetration in the soil can be known. Thereby, a bank break and a sediment disaster can be detected quickly. As a soil sensor, a sensor that measures the relative dielectric constant and conductivity of soil and measures the moisture content of the soil is known (Patent Documents 1 and 2). Using such a sensor, the amount of water in the soil can be measured in time series.

Japanese Patent Laid-Open No. 10-62368 JP 2003-329625 A

  The relationship between the dielectric constant of soil and the amount of water in the soil varies depending on the soil quality. For this reason, in the soil whose soil quality is unknown, a sample of the soil to be measured is collected by excavation such as boring. After analyzing the collected soil, a correlation curve between the dielectric constant of the soil and the amount of water is obtained. Using this correlation curve, the moisture content in the soil is measured from the dielectric constant of the soil. In this case, the cost of collecting and analyzing the soil sample is increased. Moreover, since the soil quality of a soil may change with the collection position of a soil sample, it is difficult to determine the exact soil quality of the position which installed the soil sensor. In some cases, a correlation curve between the soil permittivity and the water content is estimated without taking a soil sample. However, in this case, accurate data cannot be acquired.

  The purpose of the soil sensor and the soil sensing method is to easily determine the soil quality of the soil.

  For example, a first electrode in direct contact with soil, a reference material having water permeability and water retention, a second electrode in contact with the soil through the reference material, and the dielectric of the soil measured using the first electrode A soil sensor comprising: a determination unit that determines soil quality based on a rate and a dielectric constant of the reference material measured using the second electrode.

  For example, the dielectric constant of the soil is measured using a first electrode that is in direct contact with soil, and the dielectric constant of the reference material is measured using a second electrode that is in contact with the soil via a reference material having water permeability and water retention. Then, a soil sensing method is used in which the soil quality of the soil is determined based on the dielectric constant of the soil and the dielectric constant of the reference material.

  According to the soil sensor and the soil sensing method, the soil quality of the soil can be easily determined.

FIG. 1A and FIG. 1B are diagrams illustrating a soil sensor according to the first embodiment. FIG. 2A and FIG. 2B are block diagrams of the main body of the soil sensor according to the first embodiment. FIG. 3A and FIG. 3B are flowcharts illustrating the operation of the main body according to the first embodiment. FIG. 4 is a diagram showing an example of the relationship between the relative dielectric constant of soil and the amount of water in the soil. FIG. 5 is an example of measurement results showing the relationship between the relative permittivity ε0 ^* of the reference material and the relative permittivity ε1 ^* of the soil. FIG. 6 is a block diagram of the main body of the soil sensor according to the second embodiment. FIG. 7 is a flowchart illustrating the operation of the determination unit according to the second embodiment. FIG. 8A and FIG. 8B are schematic diagrams illustrating examples of operations of the determination unit and the calculation unit, respectively. FIG. 9 is a flowchart illustrating the operation of the calculation unit of the soil sensor according to the second embodiment. FIG. 10 is a flowchart illustrating the operation of the determination unit according to the third embodiment. FIG. 11A and FIG. 11B are schematic diagrams illustrating an example of the operation of the determination unit according to the third embodiment.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1A and FIG. 1B are diagrams illustrating a soil sensor according to the first embodiment. FIG. 1A is a schematic diagram of the soil sensor 100, and FIG. 1B is a cross-sectional view of the buried portion 26 of the soil sensor 100. As shown in FIGS. 1A and 1B, the soil sensor 100 includes an embedded part 26 and a main body part 30. The buried part 26 is buried in the soil 28. The main body 30 is installed outside the soil 28. The buried portion 26 includes the first electrode 12, the second electrode 14, the reference material 16, and the support 18. The support 18 is made of, for example, a water-impermeable material, and it is preferable that the support 18 is not submerged. Moreover, it is preferable that at least the surface of the support 18 is an insulator so as not to short-circuit between the first electrodes 12, between the second electrodes, and between the first electrode and the second electrode 14. As the support 18, for example, a resin such as acrylic or Duracon can be used. Further, the support 18 may be obtained by insulating the surface of a metal such as aluminum or iron. Since the support 18 is installed in the soil 28, the support 18 has a cylindrical shape with a sharp tip. The shape of the support 18 may be other shapes.

  A plurality of first electrodes 12 are provided on the surface of the support 18. The first electrode 12 is in direct contact with the soil 28. Further, a plurality of second electrodes 14 are provided on the surface of the support 18. The second electrode 14 is covered with a reference material 16. The reference material 16 is formed of a material having water permeability and water retention. As the reference material 16, for example, cellulose can be used. The second electrode 14 is in contact with the soil 28 via the reference material 16. The first electrode 12 and the second electrode 14 are made of a metal such as gold or copper, for example. The first electrode 12 and the second electrode 14 have a ring shape provided around the support 18. A pair of the first electrode 12 and the second electrode 14 is provided. The shape and number of the first electrode 12 and the second electrode 14 are not limited to these. One or a plurality of the first electrode 12 and the second electrode may be provided. The first electrode 12 and the main body 30 are electrically connected by a cable 20, and the second electrode 14 and the main body 30 are connected by a cable 22.

  The diameter of the support 18 can be 20 mm to 30 mm, for example. The distance between the first electrodes 12 and the distance between the second electrodes 14 in the vertical direction can be set to 5 mm to 10 mm, respectively. The interval between the first electrodes 12 and the vertical width of the second electrode 14 can be 5 mm to 10 mm, respectively. The width in the left-right direction and the length in the vertical direction of the reference material 16 are preferably large enough to measure the dielectric constant of the reference material 16. However, when the reference material 16 is too large, there is a possibility that moisture does not sufficiently penetrate into the reference material 16. The size of the reference material 16 is designed in consideration of the above.

FIG. 2A and FIG. 2B are functional block diagrams of the main body of the soil sensor according to the first embodiment. FIG. 3A and FIG. 3B are flowcharts illustrating the operation of the main body according to the first embodiment. As shown in FIG. 2A, the main body 30 includes a soil dielectric constant measurement unit 32, a reference dielectric constant measurement unit 34, and a determination unit 36. For example, a measuring instrument for measuring capacitance and a CPU (central
Processing Unit) functions as a soil dielectric constant measurement unit 32 and a reference dielectric constant measurement unit 34 by a program or the like. Further, the CPU or the like functions as the determination unit 36.

  The operation of the main body 30 will be described with reference to FIGS. 2 (a) and 3 (a). First, the soil dielectric constant measurement unit 32 is connected to the first electrode 12 by the cable 20 and measures the dielectric constant of the soil 28 using the first electrode 12 (step S10). The reference dielectric constant measurement unit 34 is connected to the second electrode 14 by the cable 22 and measures the dielectric constant of the reference material 16 using the second electrode 14 (step S12). The soil dielectric constant measuring unit 32 and the reference dielectric constant measuring unit 34 measure the capacitance between the first electrodes 12 and the second electrode 14 respectively, and the dielectric constant of the soil 28 and the reference material are measured based on the measured capacitance. A dielectric constant of 16 can be measured. The dielectric constant of the soil 28 and the dielectric constant of the reference material 16 may be measured by other methods using the first electrode 12 and the second electrode 14, respectively. Moreover, step S10 and step S12 may be performed simultaneously, and step S12 may be performed prior to step S10. The determination unit 36 determines the soil quality based on the dielectric constant ε1 of the soil 28 measured using the first electrode 12 and the dielectric constant ε0 of the reference material measured using the second electrode 14 (step S14). . Then exit.

  The operation of another main body 30 will be described with reference to FIGS. 2B and 3B. As shown in FIG. 2B, the main body 30 includes a calculation unit 38 in addition to the main body 30 shown in FIG. The CPU or the like functions as the calculation unit 38. As shown in FIG. 2B and FIG. 3B, the calculation unit 38 calculates the amount of water in the soil 28 based on the soil quality determined by the determination unit 36 and the dielectric constant ε1 of the soil 28. (Step S16). Then, the process ends.

  As mentioned above, a soil sensor provided with the main-body part 30 shown to Fig.2 (a) can determine the soil quality of soil. In addition, the soil sensor provided with the main body 30 shown in FIG. 2B can calculate the moisture content of the soil 28.

FIG. 4 is a diagram showing an example of the relationship between the relative dielectric constant of soil and the amount of water in the soil. In FIG. 4, the solid line F1 indicates the case where the soil is black soil, and the solid line F2 indicates the case where the soil is river sand. As shown in FIG. 4, the relationship between the relative permittivity ε1 ^* of the soil and the moisture content of the soil is greatly different between the black soil and the river sand.

When the volume of moisture contained in the unknown soil volume Vs is Vw, the volume content (water content) W1 of the moisture in the soil is W1 = Vw / Vs. The soil water content W1 is expressed by the following correlation curve using a dielectric constant (or relative dielectric constant) ε1.
W1 = Fn (ε1)
Here, Fn is a correlation curve for each soil.

  Thus, the moisture content in the soil can be calculated by applying the correlation curve Fn to the dielectric constant (or relative dielectric constant). However, the correlation curve Fn differs for each soil type. For this reason, the volume water content W1 cannot be calculated in a state where the soil quality is unknown.

On the other hand, when the volume Vw0 of the moisture contained in the known volume Vs0 of the reference material 16 is set, the volume content (water content) W0 of the moisture of the reference material 16 is W0 = Vw0 / Vs0. The water content W0 of the reference material 16 is expressed using the following correlation curve using a dielectric constant (or relative dielectric constant) ε0.
W0 = F0 (ε0)
Since the correlation curve F0 is known, the water content W0 in the reference material 16 can be calculated using the dielectric constant (or relative dielectric constant) ε0.

  The water content W1 of the soil and the water content W0 of the reference material 16 have a certain correlation for each soil due to the difference in water absorption between the soil and the reference material 16. For example, there is a certain correlation between F1 (ε1) and F0 (ε0).

FIG. 5 is an example of measurement results showing the relationship between the relative permittivity ε0 ^* of the reference material and the relative permittivity ε1 ^* of the soil. In FIG. 5, the measurement point of the black soil is indicated by a black circle, and the measurement point of the river sand is indicated by a white circle. The solid line is a straight line calculated from each point using the least square method. The correlation curve E1 (ε0 ^* , ε1 ^* ) of the relative permittivity ε0 ^* and ε1 ^* of black soil is different from the correlation curve E2 (ε0 ^* , ε1 ^* ) of the relative permittivity ε0 ^* and ε1 ^* of river sand.

  Accordingly, the soil quality of the soil can be estimated by measuring and comparing the dielectric constant ε1 of the soil 28 and the dielectric constant ε0 of the reference material 16. If the soil quality of the soil can be estimated, the moisture content of the soil can be calculated using the correlation curve Fn between the estimated dielectric constant of the soil and the moisture content.

  According to Example 1, as in step S14 of FIG. 3A, the permittivity of the soil 28 measured by the determination unit 36 using the first electrode 12 and the reference material 16 measured using the second electrode 14 are measured. The soil quality of the soil 28 is determined based on the dielectric constant. Thus, the soil quality of the soil 28 can be determined.

  3B, based on the soil quality of the soil 28 determined by the determination unit 36 and the dielectric constant ε1 of the soil 28 measured using the first electrode 12, the soil is determined based on the soil 28. The amount of water in 28 is calculated. Thus, the amount of water in the soil 28 can be calculated.

  FIG. 6 is a block diagram of the main body of the soil sensor according to the second embodiment. As shown in FIG. 6, the main body 30 includes a first storage unit 37 and a second storage unit 39 as compared to FIG. 2 of the first embodiment. The first storage unit 37 and the second storage unit 39 are non-volatile memory or volatile memory, such as a flash memory or a hard disk unit. The first storage unit 37 stores correlation curves En (ε0, ε1) corresponding to a plurality of soil qualities n of the soil. Here, the correlation curve En (ε0, ε1) is a correlation curve between the dielectric constant ε1 of the soil 28 corresponding to the soil quality n of the soil 28 and the dielectric constant ε0 of the reference material 16. The correlation curve En (ε0, ε1) is measured in advance for a plurality of known soil properties and stored in the first storage unit 37. The second storage unit 39 stores a correlation curve Fn between the soil permittivity ε1 and the water content W1 corresponding to the soil quality n. The correlation curve Fn is measured in advance for a plurality of known soil properties and stored in the second storage unit 39. The other configuration of the main body 30 and the buried portion 26 are the same as those in the first embodiment, and a description thereof is omitted.

  FIG. 7 is a flowchart illustrating the operation of the determination unit according to the second embodiment. As shown in FIG. 7, the determination unit 36 acquires the dielectric constant ε1 of the soil 28 from the soil dielectric constant measurement unit 32 (step S20). Next, the determination unit 36 acquires the dielectric constant of the reference material 16 from the reference dielectric constant measurement unit 34 (step S22). Step S20 and step S22 may be performed simultaneously, and step S22 may be performed prior to step S20. The determination unit 36 determines whether the process is finished (step S24). For example, when the determination unit 36 repeats steps S20 and S22 a predetermined number of times every predetermined time, the determination unit 36 determines the end. The predetermined number of times may be two times, for example. It may be 3 times or more. For example, the dielectric constant measurement can be completed earlier by setting the predetermined number of times to two. In order to improve the accuracy of soil determination, it is preferable that the dielectric constant is measured more times. Furthermore, in order to improve the accuracy of soil determination, it is preferable to measure the dielectric constant for different amounts of water. For example, the determination unit 36 may determine Yes when the difference in moisture amount or the difference in dielectric constant is equal to or greater than a predetermined value. If No in step S24, the process returns to step S20.

  In the case of Yes in step S24, the determination unit 36 calculates the correlation curve E between the dielectric constant ε1 of the soil 28 and the dielectric ε0 of the reference material 16 from the obtained dielectric constant ε1 of the soil 28 and the dielectric ε0 of the reference material 16. (Ε0, ε1) is calculated (step S26). The determination unit 36 acquires correlation curves En (ε0, ε1) corresponding to the plurality of soils n from the first storage unit 37 (step S28). The determination unit 36 determines the soil quality corresponding to En (ε0, ε1) having the highest correlation with the correlation curve E (ε0, ε1) among the correlation curves En (ε0, ε1) as the soil quality of the soil 28 (step S30). ).

  FIG. 8A and FIG. 8B are schematic diagrams illustrating examples of operations of the determination unit and the calculation unit, respectively. In FIG. 8A, the horizontal axis represents the dielectric constant ε0 of the reference material 16, and the vertical axis represents the dielectric constant ε1 of the soil 28. Correlation curves E1 to E3 are correlation curves of the dielectric constant ε1 and the dielectric constant ε0 corresponding to the soils 1 to 3 stored in the first storage unit 37. In step S26 of FIG. 7, the determination unit 36 determines the dielectric constant ε1 of the soil 28 measured using the first electrode 12 and the dielectric constant ε0 of the reference material 16 measured using the second electrode 14 for the soil 28 of unknown soil quality. A correlation curve E (ε0, ε1) is calculated. In step S30, the determination unit 36 selects a correlation curve E2 having the highest correlation with the correlation curve E (ε0, ε1) among the correlation curves E1 to E3. In the example of FIG. 8, the soil quality 2 corresponding to the correlation curve E <b> 2 is determined as the soil quality of the soil 28. As the correlation curve having the highest correlation, for example, the correlation curves E1 to E3 having the smallest average distance between the correlation curves E1 to E3 and the correlation curve E (ε0, ε1) may be selected. When the correlation curves E1 to E3 are straight lines, a correlation curve whose slope is closest to the correlation curve E (ε0, ε1) may be selected.

  FIG. 9 is a flowchart illustrating the operation of the calculation unit of the soil sensor according to the second embodiment. As illustrated in FIG. 9, the calculation unit 38 acquires the dielectric constant ε1 of the soil 28 measured from the reference dielectric constant measurement unit 34 (Step S50). The calculation unit 38 acquires the soil quality determined by the determination unit 36 (step S52). The order of steps S50 and S52 may be reversed. The calculation unit 38 acquires a correlation curve Fn corresponding to the soil quality determined by the determination unit 36 from the second storage unit 39 (step S54). The calculation unit 38 calculates the moisture content of the soil from the soil quality and the correlation curve Fn (step S56).

  In FIG. 8B, the horizontal axis is the soil dielectric constant ε1, and the vertical axis is the soil water content W1. Correlation curves F1 to F3 are correlation curves between the dielectric constant ε1 corresponding to the soils 1 to 3 stored in the second storage unit 39 and the water content. In step S54 of FIG. 9, the calculation unit 38 acquires the soil correlation curve F2 determined by the determination unit 36 (step S54). In step S56, the calculation unit 38 uses the correlation curve F2 to calculate the water content W1 ′ corresponding to the dielectric constant ε1 ′ of the soil 28 measured using the first electrode 12.

  According to the second embodiment, as in step S30 of FIG. 7, the determination unit 36 determines the dielectric constant ε1 of the soil 28 measured using the first electrode 12 and the dielectric constant of the reference material 16 measured using the second electrode 14. The soil quality of the soil 28 is determined from the rate ε0 and the correlation curve En. Thereby, since the soil quality is determined using the correlation curve En, the soil quality can be determined more accurately.

  Further, as shown in FIG. 8A, the determination unit 36 has a correlation curve that is most correlated with the measured correlation curve E (ε0, ε1) among the correlation curves En stored in the first storage unit 37. Is determined as the soil quality of the soil 28. Thereby, since the soil of the correlation curve En having the highest correlation with the measured correlation curve E is determined as the soil of the soil 28, the soil can be determined more accurately.

  Further, as shown in FIG. 8B, the calculation unit 38 calculates the soil 28 from the dielectric constant ε1 of the soil 28 measured using the first electrode 12 and the correlation curve Fn stored in the second storage unit 39. Calculate the amount of water. Thereby, the water content in the soil 28 can be calculated more accurately by calculating the water content based on the more accurately determined soil quality.

  The third embodiment is an example in which the determination unit 36 determines the soil quality by a method different from the second embodiment. In the soil sensor of the third embodiment, the structures of the buried portion 26 and the main body portion 30 are the same as those of the second embodiment, and the description thereof is omitted.

  FIG. 10 is a flowchart illustrating the operation of the determination unit according to the third embodiment. As shown in FIG. 10, the determination unit 36 acquires the dielectric constant ε1 of the soil 28 from the soil dielectric constant measurement unit 32 (step S40). Next, the determination unit 36 acquires the dielectric constant ε0 of the reference material 16 from the reference dielectric constant measurement unit 34 (step S42). Step S40 and step S42 may be performed simultaneously, and step S42 may be performed prior to step S40.

  The determination unit 36 acquires correlation curves En (ε0, ε1) corresponding to the plurality of soils n from the first storage unit 37 (step S44). The determination unit 36 extracts a correlation curve E ′ (ε0, ε1) in which at least one of the measured dielectric constant ε1 of the soil 28 and the dielectric constant ε0 of the reference material 16 is within the range from the correlation curve En (ε0, ε1). (Step S46). The determination unit 36 determines the soil quality corresponding to the correlation curve E ′ (ε0, ε1) closest to the point (ε0, ε1) among the extracted correlation curves E ′ (ε0, ε1) as the soil quality of the soil 28. Is determined (step S48). The operation of the calculation unit 38 is the same as that of the second embodiment, and a description thereof is omitted.

  FIG. 11A and FIG. 11B are schematic diagrams illustrating an example of the operation of the determination unit according to the third embodiment. 11A and 11B, the horizontal axis represents the dielectric constant ε0 of the reference material, and the vertical axis represents the dielectric constant ε1 of the soil. First, the 1st example of operation | movement of the determination part 36 of Example 3 is demonstrated using Fig.11 (a). The correlation curves E1 to E3 in FIG. 11A are the same as those in FIG. The range that the dielectric constant ε1 can take in each of the correlation curves E1 to E3 is the range R1 to R3. The measured dielectric constant of the soil 28 is ε1 ′, and the dielectric constant of the reference material is ε0 ′. In step S46 of FIG. 10, the correlation curves within the range of the measured dielectric constant ε1 ′ of the soil 28 are E2 and E3. Therefore, the determination unit 36 extracts correlation curves E1 and E2. In step S <b> 48, the determination unit 36 determines the soil corresponding to the correlation curve E <b> 3 closest to the measured points (ε0 ′, ε1 ′) among the extracted correlation curves E <b> 1 and E <b> 2 as the soil quality of the soil 28. .

  Next, a second example of the operation of the determination unit according to the third embodiment will be described with reference to FIG. Correlation curves E4 to E6 in FIG. 11B are correlation curves of different soil types. The ranges that the dielectric constant ε0 of the reference material 16 can take in the correlation curves E4 to E6 are the ranges R4 to R6. The measured dielectric constant of the soil 28 is ε1 ′, and the dielectric constant of the reference material is ε0 ′. In step S46 in FIG. 10, the correlation curves within the range of the measured dielectric constant ε0 ′ of the reference material 16 are E5 and E6. Therefore, the determination unit 36 extracts correlation curves E5 and E6. In step S <b> 48, the determination unit 36 determines the soil corresponding to the correlation curve E <b> 5 closest to the measured points (ε0 ′, ε1 ′) among the extracted correlation curves E <b> 5 and E <b> 6 as the soil quality of the soil 28. .

  Further, in the correlation curve En stored in the second storage unit 39, the determination unit 36 has the measured dielectric constant ε1 ′ of the soil 28 within a predetermined range, and the measured dielectric constant ε0 ′ of the reference material 16. May extract a correlation curve within a predetermined range.

  According to the third embodiment, as shown in FIG. 11A and FIG. 11B, the determination unit 36 includes the measured dielectric constant ε1 of the soil 28 among the correlation curves stored in the first storage unit 37. 'And a correlation curve in which the dielectric constant ε0' of the reference material 16 falls within a predetermined range are extracted. Among the extracted correlation curves, the soil quality corresponding to the correlation curve that is closest to the measured points (ε0 ′, ε1 ′) is determined as the soil quality of the soil 28. Thereby, the soil quality of the soil 28 can be determined. According to the third embodiment, since the dielectric constant is measured once using the first electrode 12 and the second electrode 14, the soil quality can be determined in a short time.

  In the soil sensor of Example 2 and Example 3, as explained in FIG. 2A and FIG. 3A of Example 1, the soil quality of the soil is determined, and the moisture content of the soil is not calculated. Also good.

In Examples 2 to 3, the example in which the soil quality of the soil 28 is determined from the correlation curve En between the dielectric constant ε1 of the soil and the dielectric constant ε0 of the reference material has been described. As a matter of course, the correlation curve En can be expressed by the relative dielectric constant ε1 ^* of the soil 28 and the relative dielectric constant ε0 ^* of the reference material 16. Further, the correlation curve En can be represented by the capacitance between the first electrodes 12 and the capacitance between the second electrodes 14. Furthermore, in Example 2 to Example 3, the example which determines the moisture content of the soil 28 from the correlation curve Fn of the dielectric constant (epsilon) 1 of soil and the moisture content Vw of soil was demonstrated. As a matter of course, the correlation curve Fn can be represented by the relative dielectric constant ε1 ^* of the soil 28 and the water content W1. Further, the correlation curve Fn can be expressed by the capacitance between the first electrodes 12 and the moisture amount W1.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

The following additional remarks are disclosed regarding the embodiment including Examples 1 to 3.
Appendix 1:
A first electrode in direct contact with the soil, a reference material having water permeability and water retention, a second electrode in contact with the soil through the reference material, and a dielectric constant of the soil measured using the first electrode A soil sensor comprising: a determination unit that determines the soil quality of the soil based on a dielectric constant of the reference material measured using the second electrode.
Appendix 2:
The soil sensor according to supplementary note 1, further comprising a calculating unit that calculates a moisture content in the soil based on the soil quality of the soil determined by the determining unit and the dielectric constant of the soil measured using the first electrode. .
Appendix 3:
A first storage unit that stores a correlation curve between a dielectric constant of the soil corresponding to a soil quality of the soil and a dielectric constant of the reference material; and the determination unit is configured to measure the soil measured using the first electrode. The supplementary note 1 or 2, wherein the soil quality is determined from a dielectric constant, a dielectric constant of the reference material measured using the second electrode, and a correlation curve stored in the first storage unit. Soil sensor.
Appendix 4:
The determination unit includes a correlation between a dielectric constant of the soil measured using the first electrode and a dielectric constant of the reference material measured using the second electrode among the correlation curves stored in the first storage unit. The soil sensor according to appendix 3, wherein the soil corresponding to the curve and the correlation curve having the most correlation is determined as the soil quality of the soil.
Appendix 5:
The determination unit includes at least one of a dielectric constant of the soil measured using the first electrode and a dielectric constant of the reference material measured using the second electrode among the correlation curves stored in the first storage unit. A correlation curve having a predetermined range is extracted, and among the extracted correlation curves, the dielectric constant of the soil measured using the first electrode and the dielectric constant of the reference material measured using the second electrode are: The soil sensor according to supplementary note 3, wherein the soil quality corresponding to the correlation curve having the closest distance to the indicated point is determined as the soil quality of the soil.
Appendix 6:
A second storage unit that stores a correlation curve between the dielectric constant of the soil corresponding to the soil quality of the soil and a moisture content; and the calculation unit uses the soil determined by the determination unit and the first electrode The soil sensor according to supplementary note 2, wherein the moisture content in the soil is calculated from the measured dielectric constant of the soil and the correlation curve.
Appendix 7:
Measuring the dielectric constant of the soil using a first electrode in direct contact with the soil, measuring the dielectric constant of the reference material using a second electrode in contact with the soil through a reference material having water permeability and water retention; The soil sensing method characterized by determining the soil quality of the soil based on the dielectric constant of the soil and the dielectric constant of the reference material.
Appendix 8
The soil sensing method according to appendix 7, wherein the moisture content in the soil is calculated based on the determined soil quality and the dielectric constant of the soil.

DESCRIPTION OF SYMBOLS 12 1st electrode 14 2nd electrode 16 Reference material 18 Support part 26 Burying part 28 Soil 30 Main body part 32 Soil dielectric constant measurement part 34 Reference dielectric constant measurement part 36 Judgment part 37 1st memory | storage part 38 Calculation part 39 2nd memory | storage part

Claims (7)

A first electrode in direct contact with the soil;
A reference material with water permeability and water retention;
A second electrode in contact with the soil via the reference material;
A determination unit that determines the soil quality of the soil based on the dielectric constant of the soil measured using the first electrode and the dielectric constant of the reference material measured using the second electrode;
A soil sensor comprising:   2. The soil according to claim 1, further comprising a calculation unit that calculates a moisture content in the soil based on the soil quality of the soil determined by the determination unit and the dielectric constant of the soil measured using the first electrode. Sensor. A first storage unit that stores a correlation curve between a dielectric constant of the soil corresponding to the soil quality of the soil and a dielectric constant of the reference material;
The determination unit includes a dielectric constant of the soil measured using the first electrode, a dielectric constant of the reference material measured using the second electrode, and a correlation curve stored in the first storage unit. The soil sensor according to claim 1 or 2, wherein the soil quality of the soil is determined.   The determination unit includes a correlation between a dielectric constant of the soil measured using the first electrode and a dielectric constant of the reference material measured using the second electrode among the correlation curves stored in the first storage unit. 4. The soil sensor according to claim 3, wherein the soil quality corresponding to the curve and the correlation curve having the most correlation is determined as the soil quality of the soil.   The determination unit includes at least a dielectric constant of the soil measured using the first electrode and a dielectric constant of the reference material measured using the second electrode among the correlation curves stored in the first storage unit. One of the extracted correlation curves is a predetermined range, and among the extracted correlation curves, the dielectric constant of the soil measured using the first electrode, and the dielectric constant of the reference material measured using the second electrode The soil sensor according to claim 3, wherein the soil quality corresponding to the correlation curve closest to the point indicated by is determined as the soil quality of the soil. A second storage unit for storing a correlation curve between the soil permittivity and the moisture content corresponding to the soil quality;
The said calculation part calculates the moisture content in the said soil from the soil quality which the said determination part determined, the dielectric constant of the said soil measured using the said 1st electrode, and the said correlation curve. Item 2. The soil sensor according to Item 2. Measure the dielectric constant of the soil using the first electrode in direct contact with the soil,
Measure the dielectric constant of the reference material using a second electrode that contacts the soil through a reference material having water permeability and water retention,
The soil sensing method characterized by determining the soil quality of the soil based on the dielectric constant of the soil and the dielectric constant of the reference material.

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