A high-precision soil salinity measuring device

Abstract

The application discloses a high-precision soil salt content measuring device, which comprises a shell, a suction filter pipe horizontally arranged on the inner side of the shell, a fixing piece vertically arranged on the inner wall of the shell, one end of the suction filter pipe penetrating the fixing piece and the surface of the shell in sequence, a fixing block arranged at the other end of the suction filter pipe, a guide rod movably arranged in the shell in the vertical direction, the fixing block and the guide rod being connected through a connecting rod, the suction filter pipe being in communication with a negative pressure pipe, an electric conductivity measuring electrode arranged in the suction filter pipe, a water content sensor connected to the upper side of the suction filter pipe, and the water content sensor and the electric conductivity measuring electrode being electrically connected with a controller. The soil extract is extracted by the device in a time-division and layer-by-layer mode, the electric conductivity of the extract is measured by a salt content probe, the measuring precision of the solution electric conductivity is relatively high, and the performance is relatively good; meanwhile, the soil water content sensor is arranged to convert the soil salt content, and the measuring precision is relatively high.

Description

Technical Field

[0001] This invention belongs to the field of soil salinity determination technology, and particularly relates to a high-precision soil salinity determination device. Background Technology

[0002] Soil salinization is one of the major obstacles to agricultural development. High-precision soil salinity monitoring equipment is an important method and means to monitor and predict the spatiotemporal distribution and variation characteristics of soil salinization. It is of great significance for preventing secondary salinization, water-saving irrigation in agriculture, improvement of saline-alkali land, safe utilization of unconventional water, and sustainable agricultural development.

[0003] High-precision monitoring technology and equipment for soil salinity is currently a challenge in the industry. Firstly, existing instruments require continuous close contact with the soil; however, changes in soil moisture cause soil shrinkage and expansion, making it difficult to achieve the ideal state. Secondly, the measured soil volume is insufficient, resulting in weak representativeness of the results, significant influence from spatial soil variability (soil texture and micro-topographic variations, etc.), and poor reproducibility. The existing EM38 geodetic conductivity meter measures the weighted average conductivity of soil layers from 0-150 cm or 0-75 cm, which cannot measure soil salinity in stratified layers or deeper soil layers, failing to meet the requirements for stratified soil salinity measurement most important in scientific research and production practice, especially for monitoring root zone salinity. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a high-precision soil salinity measuring device. This device employs timed, stratified vacuum extraction of soil extract, and uses a salinity probe to measure the conductivity of the extract. The measurement accuracy of the solution conductivity is relatively high, and the performance is good. Simultaneously, a soil moisture sensor is deployed to convert soil salinity, resulting in high measurement accuracy.

[0005] This invention provides the following technical solution:

[0006] A high-precision soil salinity measuring device includes a housing, a horizontally arranged filtration tube inside the housing, a vertically arranged fixing member on the inner wall of the housing, one end of the filtration tube passing through the fixing member and the surface of the housing in sequence, and a fixing block at the other end of the filtration tube. A guide rod capable of moving vertically is arranged inside the housing, and the fixing block and the guide rod are connected by a connecting rod. The filtration tube can be connected to a negative pressure tube. A conductivity measuring electrode is arranged inside the filtration tube, and a moisture sensor is connected to the upper side of the filtration tube. Both the moisture sensor and the conductivity measuring electrode are electrically connected to a controller.

[0007] Preferably, the fixing member is provided with a guide groove, the filter tube is located in the guide groove, the filter tube can move in the guide groove, and the surface of the filter tube is provided with through holes, the through holes including a first through hole provided on the upper surface of the filter tube and a second through hole provided on the front and rear surfaces of the filter tube.

[0008] Preferably, the negative pressure tube is located inside the fixing member, the negative pressure tube is provided with a negative pressure port, the opening of the negative pressure port is located in the guide groove, and the surface of the suction tube is provided with an air extraction port. When the suction tube is extended, the air extraction port is directly opposite the negative pressure port.

[0009] Preferably, a guide member is provided on the inner wall of the housing, and the guide rod is located inside the guide member and can move within the guide member.

[0010] Preferably, the upper end of the housing is provided with a column, the column is connected to a pressure handle, the pressure handle is connected to a pressure block, the upper end of the guide rod is provided with a horizontal plate, and the pressure block can contact the horizontal plate.

[0011] Preferably, the end of the filtration tube is provided with a tapered part, the bottom of the inner side of the filtration tube is provided with an electrode plate support, the conductivity measuring electrode is disposed on the electrode plate support, and the height of the second through holes on the front and rear sides of the filtration tube is higher than the height of the top of the conductivity measuring electrode.

[0012] Preferably, the length of the filter tube is L, and the height of the conical member is h. In order for the filter tube to be smoothly inserted into the soil, h is greater than or equal to 1 / 4L.

[0013] Preferably, the length of the connecting rod is d. When the filter tube is located inside the shell, the angle between the connecting rod and the guide rod is θ, where θ is greater than or equal to 45 degrees. The length of the connecting rod d and the height of the tapered part h satisfy the following relationship: d·(1-sinθ)=m·h, where m ranges from 1 to 3, and the units of d, h, and L are all mm.

[0014] Preferably, a filter screen is provided on the inner wall of the suction pipe, and the filter screen is used to filter the mud and water entering the suction pipe.

[0015] Preferably, a one-way valve is provided at the tail end of the upper surface of the filtration tube. The inlet end of the one-way valve is connected to a first drain pipe, and the other end of the first drain pipe extends to the bottom of the filtration tube. The outlet end of the one-way valve is connected to a second drain pipe, and the other end of the second drain pipe extends to the outside of the housing and is connected to a water pump. The water pump is used to extract the solution from the filtration tube.

[0016] Preferably, a fixing post is provided on the lower surface of the shell, which can be inserted into the soil to increase the stability of the shell during use.

[0017] Preferably, the device further includes a pit shovel, which has a rectangular tubular structure, with an acute angle at the lower end. The width of the pit shovel is greater than or equal to the width of the shell, and the length of the pit shovel is greater than or equal to the length of the shell. The surface of the pit shovel is provided with scale lines.

[0018] Preferably, a high-precision method for determining soil salinity includes the following steps:

[0019] S1: Excavation of the foundation pit. A foundation pit of a certain depth is excavated using a foundation pit shovel. The length and width of the foundation pit should be such that a salt content measuring device can be placed inside.

[0020] S2: Place the salinity measuring device in the pit, ensuring that the end with the filter tube is tightly against the inner wall of the pit. Fill the other three sides of the salinity measuring device with soil to fix it in place.

[0021] S3: The filter tube is in place. Press the handle, and the guide rod moves downward. Under the action of the connecting rod, the filter tube extends and penetrates into the soil.

[0022] S4: Soil moisture content measurement, which involves determining the soil moisture content using a moisture sensor and recording the data;

[0023] S5: Soil solution vacuum filtration. Air is extracted from the filtration tube through a negative pressure tube, creating a negative pressure inside the filtration tube. The solution in the soil enters the filtration tube through the through-holes on the filtration tube. Then, the conductivity of the soil solution is measured by electrodes.

[0024] S6: Determining soil salinity involves converting electrical conductivity to salinity using the formula for salt content calibration, and then combining this with soil moisture content to calculate the actual salinity of the soil.

[0025] Preferably, during the excavation of the foundation pit, the shape of the foundation pit should be kept vertical, and the bottom of the foundation pit should be kept flat so as not to affect the stability of the salt content measuring device. The interval between soil moisture content measurement and vacuum filtration of soil solution is 5-10 minutes.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention provides a high-precision soil salinity measuring device, which uses timed stratified vacuum extraction of soil extract and uses a salinity probe to measure the conductivity of the extract. The measurement accuracy of the solution conductivity is relatively high and the performance is good. At the same time, a soil moisture sensor is set up to convert the soil salinity, and the measurement accuracy is relatively high.

[0028] (2) The present invention provides a high-precision soil salinity measuring device. By setting up multiple sets of vacuum filtration tubes, the vacuum filtration tubes perform vacuum extraction of soil leachate from soil at different heights, thereby realizing the stratified measurement of soil salinity and meeting the requirements of stratified measurement of soil salinity in scientific research and production practice.

[0029] (3) The present invention provides a high-precision soil salinity measuring device. By setting a water pump, the extract in the filter tube can be discharged in time, avoiding the influence of the extract on the next measurement result. The device is relatively convenient to use. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0032] Figure 2 This is a structural diagram of the fastener of the present invention.

[0033] Figure 3 This is a schematic diagram of the suction filter tube of the present invention.

[0034] Figure 4 This is a structural diagram of the internal structure of the suction filter tube of the present invention.

[0035] Figure 5 This is a schematic diagram of the pit shovel structure of the present invention.

[0036] In the diagram: 1. Housing; 2. Filter tube; 3. Moisture sensor; 4. Fixing component; 5. Negative pressure tube; 6. Column; 7. Handle; 8. Pressing block; 9. Horizontal plate; 10. Wire; 11. Guide rod; 12. Guide component; 13. Connecting rod; 14. Fixing block; 15. Negative pressure port; 16. Guide groove; 17. First through hole; 18. Air extraction port; 19. Second through hole; 20. Conductivity measuring electrode; 21. Electrode plate support; 22. Conical component; 23. One-way valve; 24. Pit shovel. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] Example 1:

[0040] like Figure 1-5 As shown, a high-precision soil salinity measuring device includes a housing 1. A horizontally arranged suction tube 2 is mounted inside the housing 1, and the suction tube 2 is under negative pressure to extract leachate from the soil. A fixing member 4 is vertically mounted on the inner wall of the housing 1. One end of the suction tube 2 passes through the fixing member 4 and the surface of the housing 1, respectively. The fixing member 4 supports the suction tube 2, increasing the structural stability of the device. A fixing block 14 is mounted on the other end of the suction tube 2. A guide rod 11 capable of moving vertically is installed inside the housing 1. The fixing block 14 and the guide rod 11 are connected by a connecting rod 13. When the guide rod 11 moves vertically, the connecting rod... Driven by 13, the filtration tube 2 can move to the left or right. The filtration tube 2 can be connected to the negative pressure tube 5, which is connected to an external negative pressure pump. The filtration tube 2 is equipped with a conductivity measuring electrode 20, which is used to measure the conductivity of the extract. A moisture sensor 3 is connected to the upper side of the filtration tube 2. Both the moisture sensor 3 and the conductivity measuring electrode 20 are electrically connected to the controller through wire 10. The moisture sensor 3 is used to measure the soil moisture content. The conductivity of the soil solution is measured by the electrode, and the conductivity is converted into salt content according to the calibration formula of salt content. Then, combined with the soil moisture content, the actual salt content of the soil is calculated.

[0041] The fixing member 4 is provided with a guide groove 16, the filtration tube 2 is located in the guide groove 16, the filtration tube 2 can move in the guide groove 16, the surface of the filtration tube 2 is provided with through holes, the through holes include a first through hole 17 provided on the upper surface of the filtration tube and a second through hole 19 provided on the front and rear surfaces of the filtration tube, the extract in the soil flows into the filtration tube 2 through the through holes.

[0042] The negative pressure pipe 5 is located inside the fixing member 4. A negative pressure port 15 is provided on the negative pressure pipe 5, and the opening of the negative pressure port 15 is located within the guide groove 16. An air extraction port 18 is provided on the surface of the suction pipe 2. When the suction pipe 2 extends, the air extraction port 18 is directly opposite the negative pressure port 5. A sealing gasket is provided at the air extraction port 18 to increase the sealing between the negative pressure port 5 and the air extraction port 18. A guide member 12 is provided on the inner wall of the housing 1, and a guide rod 11 is located within the guide member 12, allowing the guide rod 11 to move within the guide member 12. The guide member 12 serves to guide and limit the movement of the guide rod 11.

[0043] The upper end of the housing 1 is provided with a column 6, the column 6 is connected to a pressure handle 7, and the pressure handle 7 is connected to a pressure block 8. The pressure handle 7 and the column 6 are hinged, and the pressure handle 7 and the pressure block 8 are hinged. The upper end of the guide rod 11 is provided with a horizontal plate 9, and the pressure block 8 can contact the horizontal plate 9. When the pressure handle 7 rotates downward, the pressure block 8 acts on the horizontal plate 9, which can make the guide rod 11 move downward. The end of the filtration tube 2 is provided with a tapered part 22. The tapered part 22 facilitates the insertion of the filtration tube 2 into the soil to extract soil extract. The bottom inner side of the filtration tube 2 is provided with an electrode plate support 21, and the conductivity measuring electrode 20 is set on the electrode plate support 21. The height of the second through holes 19 on the front and rear sides of the filtration tube 2 is higher than the height of the top of the conductivity measuring electrode 20, which facilitates the storage of extract. A filter screen is installed on the inner wall of the filtration tube 2, which is used to filter the mud and water entering the filtration tube 2. Multiple filtration tubes 2 are evenly arranged vertically along the inner wall of the shell 1 to facilitate the layered measurement of soil salinity.

[0044] A one-way valve 23 is provided at the tail end of the upper surface of the filtration tube 2. When the one-way valve is working, the liquid in the one-way valve flows from the inside of the filtration tube 2 to the outside. The inlet end of the one-way valve 23 is connected to a first drain pipe, and the other end of the first drain pipe extends to the bottom of the filtration tube 2. The outlet end of the one-way valve is connected to a second drain pipe, and the other end of the second drain pipe extends to the outside of the housing 1 and is connected to a water pump. The water pump is used to extract the solution in the filtration tube 2 to avoid affecting the next measurement of the extract, and to facilitate multiple extractions of soil extract and measurement of the conductivity of the soil extract.

[0045] The device also includes a pit shovel 24, which has a rectangular tubular structure with an acute angle at the lower end. The width of the pit shovel 24 is greater than or equal to the width of the housing 1, and the length of the pit shovel 24 is greater than or equal to the length of the housing 1. The surface of the pit shovel 24 is provided with scale lines to facilitate understanding the depth of the excavated pit. The pit shovel 24 is used to excavate holes adapted to the device, facilitating the placement of the device into the holes.

[0046] Example 2

[0047] The length of the filter tube is L, and the height of the conical component is h. In order for the filter tube to be smoothly inserted into the soil, h is greater than or equal to 1 / 4L. When h is less than 1 / 4L, the soil resistance to the conical component is greater, and the conical component is not easy to be inserted into the soil. The length of the connecting rod is d. When the filter tube is located inside the shell, the angle between the connecting rod and the guide rod is θ, where θ is greater than or equal to 45 degrees. When θ is less than 45 degrees, the connecting rod and the guide rod are prone to jamming when the guide rod moves downward, resulting in uneven rotation of the connecting rod. When θ is greater than or equal to 45 degrees, the connecting rod can rotate smoothly, allowing the conical part to penetrate smoothly into the soil. The length d of the connecting rod and the height h of the conical part satisfy the following relationship: d·(1-sinθ)=m·h, where m ranges from 1 to 3. The units of d, h, and L are all mm. When m ranges from 1 to 3, combined with the soil hardness, it can ensure that the filter tube is completely inserted into the soil, and the measurement accuracy is high. When m ranges from less than 1, the length of the filter tube penetrating into the soil is small, and the measurement accuracy is poor. When m ranges from greater than 3, the length of the filter tube penetrating into the soil is large, resulting in lower working efficiency.

[0048] Example 3

[0049] A high-precision method for determining soil salinity includes the following steps:

[0050] S1: Excavation of the foundation pit. A foundation pit of a certain depth is excavated using a foundation pit shovel. The length and width of the foundation pit should be such that a salt content measuring device can be placed inside.

[0051] S2: Place the salinity measuring device in the pit, ensuring that the end with the filter tube is tightly against the inner wall of the pit. Fill the other three sides of the salinity measuring device with soil to fix it in place.

[0052] S3: The filter tube is in place. Press the handle, and the guide rod moves downward. Under the action of the connecting rod, the filter tube extends and penetrates into the soil.

[0053] S4: Soil moisture content measurement, which involves determining the soil moisture content using a moisture sensor and recording the data;

[0054] S5: Soil solution vacuum filtration. Air is extracted from the filtration tube through a negative pressure tube, creating a negative pressure inside the filtration tube. The solution in the soil enters the filtration tube through the through-holes on the filtration tube. Then, the conductivity of the soil solution is measured by electrodes.

[0055] S6: Determining soil salinity involves converting electrical conductivity to salinity using the formula for salt content calibration, and then combining this with soil moisture content to calculate the actual salinity of the soil.

[0056] During the excavation of the foundation pit, the shape of the foundation pit should be kept vertical, and the bottom of the foundation pit should be kept flat so as not to affect the stability of the salt content measuring device. The interval between soil moisture content measurement and soil solution vacuum filtration should be 5-10 minutes.

[0057] The device obtained through the above technical solution is a high-precision soil salinity measuring device. In the process of measuring soil salinity, a pit is first dug in the ground, the device is placed in the pit and fixed. Then, the pressure handle 7 is rotated downwards, the guide rod moves downwards, and under the action of the connecting rod 13, the suction tube 2 moves to the left and penetrates into the soil layer. The soil moisture content is measured using the moisture sensor 3. After an interval of 5-10 minutes, the negative pressure pump is started to create a negative pressure environment in the suction tube, extracting the leachate from the soil. The conductivity of the leachate is measured using the conductivity measuring electrode 20. The conductivity is converted to salinity using the formula, and then combined with the soil moisture content to calculate the actual soil salinity. The device uses timed, layered vacuum extraction of the soil leachate and a salinity probe to measure the conductivity of the leachate, resulting in high accuracy and good performance in measuring solution conductivity. Simultaneously, soil moisture sensors are deployed for soil salinity conversion, achieving high measurement accuracy.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations; any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-precision soil salinity measuring device, characterized in that, The device includes a housing (1), on which multiple sets of filtration tubes (2) are arranged horizontally in layers on the inner side. A fixing member (4) is arranged vertically on the inner wall of the housing (1). One end of the filtration tube (2) passes through the fixing member (4) and the surface of the housing (1) in sequence. A fixing block (14) is arranged at the other end of the filtration tube (2). A guide rod (11) that can move in the vertical direction is arranged inside the housing (1). The fixing block (14) and the guide rod (11) are connected by a connecting rod (13). When the guide rod (11) moves in the vertical direction, the filtration tube (2) can move to the left or right under the drive of the connecting rod (13). The filtration tube (2) can be connected to a negative pressure tube (5). A conductivity measuring electrode (20) is arranged inside the filtration tube (2). A moisture sensor (3) is connected to the upper side of the filtration tube (2). The moisture sensor (3) and the conductivity measuring electrode (20) are both electrically connected to the controller. The upper end of the housing (1) is provided with a column (6), the column (6) is connected to a pressure handle (7), the pressure handle (7) is connected to a pressure block (8), the upper end of the guide rod (11) is provided with a horizontal plate (9), and the pressure block (8) can contact the horizontal plate (9); the end of the suction tube (2) is provided with a tapered part (22), the bottom of the inner side of the suction tube (2) is provided with an electrode plate support (21), the conductivity measuring electrode (20) is provided on the electrode plate support (21), and the height of the second through hole (19) on the front and rear sides of the suction tube (2) is higher than the height of the top of the conductivity measuring electrode (20); The length of the filter tube is L, the height of the conical part is h, h≥1 / 4L; the length of the connecting rod is d, and when the filter tube is located inside the shell, the angle between the connecting rod and the guide rod is θ, θ≥45°, and d·(1-sinθ)=m·h, where m takes values ​​from 1 to 3.

2. The high-precision soil salinity measuring device according to claim 1, characterized in that, The fixing member (4) is provided with a guide groove (16), the filter tube (2) is located in the guide groove (16), the filter tube (2) can move in the guide groove (16), the surface of the filter tube (2) is provided with a through hole, the through hole includes a first through hole (17) provided on the upper surface of the filter tube and a second through hole (19) provided on the front and rear surfaces of the filter tube.

3. The high-precision soil salinity measuring device according to claim 2, characterized in that, The negative pressure pipe (5) is located inside the fixing member (4). The negative pressure pipe (5) is provided with a negative pressure port (15). The opening of the negative pressure port (15) is located in the guide groove (16). The surface of the suction pipe (2) is provided with an air extraction port (18). When the suction pipe (2) is extended, the air extraction port (18) is directly opposite the negative pressure port (15).

4. The high-precision soil salinity measuring device according to claim 1, characterized in that, A guide (12) is provided on the inner wall of the housing (1), and the guide rod (11) is located inside the guide (12) and can move inside the guide (12).

5. The high-precision soil salinity measuring device according to claim 1, characterized in that, A filter screen is provided on the inner wall of the filter tube (2), and the filter screen is used to filter the mud and water entering the filter tube (2).

6. A high-precision soil salinity determination method for use in the high-precision soil salinity determination device according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Excavation of the foundation pit. A foundation pit of a certain depth is excavated using a foundation pit shovel. The length and width of the foundation pit should be such that a salt content measuring device can be placed inside. S2: Place the salinity measuring device in the pit, ensuring that the end with the filter tube is tightly against the inner wall of the pit. Fill the other three sides of the salinity measuring device with soil to fix it in place. S3: The filter tube is in place. Press the handle, and the guide rod moves downward. Under the action of the connecting rod, the filter tube extends and penetrates into the soil. S4: Soil moisture content measurement, which involves determining the soil moisture content using a moisture sensor and recording the data; S5: Soil solution vacuum filtration. Air is extracted from the filtration tube through a negative pressure tube, creating a negative pressure inside the filtration tube. The solution in the soil enters the filtration tube through the through-holes on the filtration tube. Then, the conductivity of the soil solution is measured by electrodes. S6: Determining soil salinity involves converting electrical conductivity to salinity using the formula for salt content calibration, and then combining this with soil moisture content to calculate the actual salinity of the soil.

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