A device and method for in-situ detection of seed spacing and seeding depth based on magnetic field induction

Abstract

This invention relates to a device and method for in-situ detection of seeding spacing and depth based on magnetic field induction, belonging to the field of intelligent agricultural machinery equipment technology. It includes a mounting base at the rear end of a precision seeder, a vertical rod mounted on the mounting base, and a cutting shovel at the lower end of the vertical rod. The cutting shovel has two opposing cutting plates, and the opposing sides of the two cutting plates are respectively equipped with multi-dimensional high-precision magnetic sensing modules for detecting magnetic induction intensity information. It also includes a controller and a GPS wireless speed measuring device. The GPS wireless speed measuring device is used to measure the real-time operating speed of the precision seeder. The controller is electrically connected to both the GPS wireless speed measuring device and the multi-dimensional high-precision magnetic sensing modules. This application can solve the problems of current methods for detecting seeding spacing and depth after sowing operations, which rely on manual labor, have poor detection accuracy, and low detection efficiency.

Description

Technical Field

[0001] This invention relates to the field of intelligent agricultural machinery and equipment, specifically to an in-situ detection device and method for seeding spacing and depth based on magnetic field induction. Background Technology

[0002] Sowing is a crucial step in crop production, and the quality of sowing directly affects the final crop yield. The quality of sowing largely depends on the performance of the seeder. Accurately and objectively evaluating the performance of the seeder is the primary task in optimizing and upgrading machinery and ensuring sowing quality.

[0003] There are also methods, both domestically and internationally, to determine seed spacing and sowing depth by measuring the number of seedlings after emergence. The plant spacing is used as the seed spacing, and the vertical length of the stem between the seed and the ground surface is used as the sowing depth. Compared to manual seed removal, this method is relatively convenient for measuring plant spacing. However, seed germination is affected by factors such as seed vigor, soil moisture, and seed-soil contact. Some seeds sown may not germinate normally, meaning that plant spacing cannot completely replace the actual seed spacing of the seeder. Evaluating the seeder's performance by measuring plant spacing is inaccurate. Furthermore, this method requires completely removing the soil around the seedling roots when measuring sowing depth, which is also time-consuming and labor-intensive.

[0004] Because seeds themselves do not possess the characteristics required for conventional detection techniques, and due to the complexity of farmland soil environments, there is limited research in China on in-situ online detection of seed spacing and sowing depth. Existing patent CN202310069844.0 discloses a device and method for in-situ ultrasonic detection of ridge-planted wheat seeds. This invention utilizes an ultrasonic transmitter to emit ultrasonic signals into the soil, and determines the presence of wheat seeds based on the reflected ultrasonic signals. While this method is novel, it requires compressing the soil for testing. Various soil clods, straw, and other impurities significantly affect the propagation of ultrasonic signals, and it can only perform localized sampling, resulting in low detection efficiency and an inability to achieve real-time online detection of seed spacing and depth.

[0005] Patent CN202311244136.2 discloses a method and device for detecting sowing depth and seed spacing. This invention utilizes a hyperspectral camera to identify seeds in the seed furrow in real time, measures the seeder's operating speed using radar, and then obtains the seed spacing; it also uses a depth camera and angle sensor to measure sowing depth in real time. This invention employs machine vision to measure seed spacing and depth, using relatively advanced technology and enabling real-time detection. However, the hyperspectral camera and depth camera used are difficult to adapt to harsh farmland environments, and the device is expensive, making it unsuitable for practical production. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an in-situ detection device and method for seed spacing and sowing depth based on magnetic field induction, in order to solve the problems of current seed spacing and sowing depth detection relying on manual labor, poor detection accuracy, and low detection efficiency.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: an in-situ detection device for seeding spacing and seeding depth based on magnetic field induction, characterized in that it includes a mounting base set at the rear end of a precision seeder, a vertical rod set on the mounting base, and a cutting shovel set at the lower end of the vertical rod. The cutting shovel has two oppositely arranged cutting plates, and the opposite sides of the two cutting plates are respectively provided with multi-dimensional high-precision magnetic sensing modules for detecting magnetic induction intensity information. It also includes a controller and a GPS wireless speed measuring device. The GPS wireless speed measuring device is used to measure the real-time operating speed of the precision seeder, and the controller is electrically connected to the GPS wireless speed measuring device and the multi-dimensional high-precision magnetic sensing modules respectively.

[0008] As a preferred embodiment, the precision seeder is equipped with a tractor at the front for towing the precision seeder, the controller is located inside the tractor, the GPS wireless speed measuring device is located on the top of the tractor, and a human-machine interaction display terminal is also located inside the tractor, which is connected to the controller.

[0009] As a preferred embodiment, the mounting base is hinged to the rear end of the precision seeder, and a parallelogram linkage mechanism is provided on the vertical rod. The rear end of the parallelogram linkage mechanism is provided with depth limiting wheels on both sides of the cutting shovel, and the lower end of the depth limiting wheel is flush with the top of the cutting shovel.

[0010] As a preferred embodiment, a horizontal plate is provided on the vertical pole, and an electric push rod is provided between the horizontal plate and the upper end of the cutting shovel.

[0011] As a preferred embodiment, the multidimensional high-precision magnetic sensor module includes a housing and multiple miniature magnetic sensors disposed within the housing, the multiple miniature magnetic sensors being arranged in a rectangular array.

[0012] This application also provides a method for in-situ detection of seeding spacing and depth based on a magnetic field induction-based in-situ detection device, comprising the following steps:

[0013] S1. Coat the seeds to be sown with iron powder to obtain iron powder coated seeds;

[0014] S2. Magnetize the iron powder-coated seeds to obtain magnetized seeds;

[0015] S3. Sow the magnetized seeds using a precision seeder;

[0016] S4. Calculate the seed spacing:

[0017] The controller receives magnetic induction intensity information from multiple miniature magnetic sensors, determines whether the collected magnetic induction intensity information comes from magnetized seeds, increments the counter by 1 and starts a timer if so, otherwise waits to receive the next magnetic induction intensity information; when the second magnetic induction intensity is received, the timer value is decremented, the time interval Δt between two adjacent seed signals is calculated, the counter variable is set to 1, and the timer is cleared to 0. The seed spacing is then calculated using the following formula:

[0018]

[0019] In the formula, s is the seed spacing in cm, Δt is the time interval between detecting two adjacent seeds in s, and v is the operating speed of the precision seeder in km / h;

[0020] S5. Calculate the sowing depth:

[0021] The controller receives magnetic field strength information from multiple miniature magnetic sensors, compares the magnitudes of the magnetic field strengths, determines the maximum magnetic field strength, and calculates the sowing depth using the following formula:

[0022]

[0023] In the formula, B is the magnetic flux density T, μ0 is the free permeability T·m / A, and μ r T is the relative magnetic permeability of the soil, and m is the magnetic dipole moment, A·m. 2 , Let r be the unit vector pointing from the magnetic seed to the miniature magnetic sensor, and let m be the distance from the magnetized seed to the miniature magnetic sensor.

[0024] As a preferred embodiment, in step S1, ferrite powder or neodymium iron boron powder is used as the coating material, and a coating film-forming agent is used as the binder to coat the seeds with iron powder, thereby obtaining iron powder coated seeds.

[0025] As a preferred option, in step S2, the iron powder-coated seeds are magnetized using a magnetizer to obtain magnetized seeds with a magnetic induction intensity of 5-7 mT on the surface of the magnetized seeds.

[0026] In step S4, determining whether the collected magnetic induction intensity information comes from the magnetization seed includes the following steps:

[0027] S41. Select soil samples from the sowing area, prepare soil samples with different moisture contents, soil organic matter content, and pH values. Place magnetized seeds in soil samples with different depths and soil properties, and use a magnetic induction sensor to measure the magnetic induction intensity of the seeds at different soil properties and depths. Establish a mathematical model between soil properties, detection distance, and magnetic induction intensity, as shown below:

[0028] B = f (SMC, SOM, r) (3)

[0029] In the formula, B is the magnetic induction intensity T, SMC is the soil moisture content, SOM is the soil organic matter content g / kg, and r is the distance from the magnetized seed to the micro magnetic sensor in m.

[0030] S42. Before sowing, the soil properties of the area to be sown are measured to obtain the distance D between the magnetized seed and the micro magnetic sensor, which is between [D1, D2]. The soil properties and the distance D range are input into the prediction model to obtain the distribution range of the magnetic induction intensity of the magnetized seed [B1, B2].

[0031] S44. If the measured magnetic induction intensity of the magnetized seed is between [B1, B2], it is considered a magnetized seed; otherwise, it is considered a magnetic foreign object.

[0032] The beneficial effects of this application are: it enables real-time and precise measurement of the spacing and depth of seeds in the soil during the sowing process, greatly improving the accuracy and efficiency of detection, providing technical support for the accurate evaluation of the quality of the seeder operation, and is of great significance for promoting the innovative research and development and performance improvement of the seeder, thereby ensuring the quality of sowing and promoting increased production and income. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the precision seeder of this application;

[0034] Figure 2 This is the front view of the cutting shovel in this application;

[0035] Figure 3 This is an isometric view of the cutting blade of this application;

[0036] Figure 4 This is a schematic diagram of the installation of the multi-dimensional high-precision magnetic sensing module of this application at the cutting blade.

[0037] Figure 5 This is a schematic diagram of the tractor, precision seeder, and cutting blade used in this application;

[0038] Figure 6 This is a schematic diagram showing the distribution of the miniature magnetic sensor in the multidimensional high-precision magnetic sensing module of this application.

[0039] Figure 7 This is a flowchart illustrating the in-situ detection method for seeding spacing and seeding depth in this application.

[0040] Figure 8 This is a flowchart illustrating the seed spacing calculation for this application;

[0041] Figure 9 This is a flowchart illustrating the calculation of seeding depth in this application;

[0042] Figure 10 This is a schematic diagram showing the positional relationship between the magnetized seed and the micro magnetic sensor in this application.

[0043] Reference numerals: 1. Crossbeam, 2. Fan, 3. Air duct, 4. Parallel four-bar linkage, 5. Seed box, 6. Seed metering device, 7. Motor, 8. Seed guide tube, 9. Double disc furrow opener, 10. Contouring wheel, 11. Soil covering and pressing wheel, 12. Frame, 13. Mounting base, 131. Connecting rod, 14. Vertical rod, 141. Horizontal plate, 15. Electric push rod, 16. Depth limiting spring, 17. Parallelogram linkage mechanism, 171. Upper connecting plate, 172. Lower connecting plate, 173. Middle vertical plate, 174. Inclined part, 18. Depth limiting wheel, 19. Soil cutting shovel, 191. Soil cutting plate, 20. Multi-dimensional high-precision magnetic sensing module, 21. GPS wireless speed measuring device, 22. Controller, 23. Human-machine interaction display terminal, 24. Miniature magnetic sensor. Detailed Implementation

[0044] The following is in conjunction with the appendix Figure 1-10 The present invention will be further described in detail with reference to specific embodiments.

[0045] This application provides an in-situ detection device for seeding spacing and depth based on magnetic field induction, including a mounting base 13 at the rear end of a precision seeder, a vertical rod 14 on the mounting base 13, and a cutting shovel 19 at the lower end of the vertical rod 14. The cutting shovel 19 has two oppositely arranged cutting plates 191. The opposite sides of the two cutting plates 191 are respectively provided with a multi-dimensional high-precision magnetic sensing module 20 for detecting magnetic induction intensity information. It also includes a controller 22 and a GPS wireless speed measuring device 21. The GPS wireless speed measuring device 21 is used to measure the real-time operating speed of the precision seeder. The controller 22 is electrically connected to the GPS wireless speed measuring device 21 and the multi-dimensional high-precision magnetic sensing module 20.

[0046] Specifically, the precision seeder in this application, such as Figure 1 As shown, the precision seeder mainly includes a crossbeam 1, a fan 2, an air duct 3, a parallel four-bar linkage 4, a seed box 5, a seed metering device 6, a motor 7, a seed guide tube 8, a double disc furrow opener 9, a contour wheel 10, a soil covering and pressing wheel 11, and a frame 12.

[0047] Fan 2 is mounted on crossbeam 1. The outlet of fan 2 is connected to the air inlet of seed metering device 6 via air duct 3, providing negative pressure to seed metering device 6. Parallel four-bar linkage 4 is connected to crossbeam 1 to adapt to undulating terrain and provide suitable downforce. Seed box 5 is mounted on frame 12 to supply seeds to seed metering device 6. Seed inlet of seed metering device 6 is connected to seed box 5, seed dispensing port is connected to seed guide pipe 8, air inlet is connected to fan 2 via air duct 3, and motor 7 provides power for the rotation of seed metering device 6. After the seeds in seed box 5 enter seed metering device 6, they are adsorbed by negative pressure airflow. Motor 7 drives seed metering device 6 to rotate, and when it rotates to seed dispensing port, the seeds are dispensed into seed guide pipe 8. Seed guide pipe 8 is connected to seed dispensing port of seed metering device 6, and the seeds reach the seed furrow along the pipe wall of seed guide pipe 8. Double disc furrow opener 9 is installed in front of seed guide pipe 8 to open seed furrows of suitable depth. The contouring wheel 10 is installed on both sides of the double-disc furrow opener 9 to adapt to uneven ground and ensure consistent sowing depth. The soil covering and compaction wheel 11 is installed at the rear of the furrow opener 9 to cover the seed furrows with soil and compact the topsoil.

[0048] During sowing, seeds in seed box 5 fall into seed metering device 6. Seed metering device 6 uses negative pressure airflow to attract seeds and rotates to seed inlet driven by motor 7, feeding seeds into seed guide tube 8. Seeds fall along the inner wall of seed guide tube 8 into seed furrows opened by double disc furrow opener 9. Soil covering and compaction wheel 11 covers and compacts the seed furrows. Alternatively, the precision seeder of this application can also use existing commonly used precision seeders, such as the precision seeder in existing patent CN200320104976.0.

[0049] Mounting base 13 is hinged to the rear end of precision seeder. Mounting base 13 has a connecting rod 131 at the front end, which is hinged to the rear end of precision seeder. A parallelogram linkage mechanism is provided on vertical rod 14. The rear end of the parallelogram linkage mechanism is provided with depth limiting wheels 18 on both sides of cutting shovel 19. The lower end of the depth limiting wheel 18 is flush with the top of cutting shovel 19.

[0050] The parallelogram linkage mechanism includes two symmetrically arranged linkage assemblies. Each linkage assembly includes an upper connecting plate 171, a lower connecting plate 172, and a middle vertical plate 173. One end of the upper connecting plate 171 is hinged to the vertical rod 14, and the other end is hinged to the upper end of the middle vertical plate 173. One end of the lower connecting plate 172 is hinged to the vertical rod 14, and the other end is hinged to the lower end of the middle vertical plate 173. The lower end of the middle vertical plate 173 has an inclined portion 174 that slopes downwards, and a depth-limiting wheel 18 is hinged to the rear end of the inclined portion 174. A depth-limiting spring 16 is provided between the lower connecting plate 172 and the vertical rod 14. The depth-limiting spring 16 is a tension spring and has a first hook and a second hook. The lower connecting plate 172 has a first hook hole that engages with the first hook, and the vertical rod 14 has multiple second hook holes along the vertical direction that engage with the second hook. The cutting shovel 19 is n-shaped and is used to carry the multi-dimensional high-precision magnetic sensing module 20 and cut into the soil.

[0051] A horizontal plate is provided on the vertical rod 14, and an electric push rod 15 is provided between the horizontal plate and the upper end of the cutting shovel 19. The width and depth of the cutting shovel 19 need to be determined according to the agronomic requirements of the crop being sown. Taking corn as an example, when sowing corn, the furrow width of the double disc furrow opener is 30-50mm, and the suitable sowing depth is 40-60mm. Therefore, for corn sowing, the width of the cutting shovel 19 can be designed to be 60mm, and the working depth to be 80mm.

[0052] The multi-dimensional high-precision magnetic sensing module 20 includes a housing and multiple miniature magnetic sensors 24 disposed within the housing, arranged in a rectangular array. The cutting blade 191 has grooves on opposite sides that mate with the housing, and the housing is bolted into these grooves. The lower end of the depth-limiting wheel 18 is flush with the top of the cutting blade 19, ensuring a stable working depth for the cutting blade 19. An electric push rod 15 is mounted on the upper part of the cutting blade, providing sufficient pressure to maintain a constant working depth for the cutting blade 19.

[0053] The multidimensional high-precision magnetic sensor module 20 includes multiple miniature magnetic sensors 24, each 15mm long and 10mm wide. To ensure detection accuracy, two miniature magnetic sensors 24 are arranged horizontally, allowing for two detections of the corn seeds. The longitudinal spacing and number of miniature magnetic sensors 24 are determined based on the minimum external dimensions and sowing depth of the seeds. Taking corn as an example, the minimum external dimension (thickness) of corn is approximately 5mm. Therefore, the maximum longitudinal spacing between two miniature magnetic sensors 24 is 5mm to ensure detection even when the seeds are lying flat. The suitable sowing depth for corn is 40–60mm, so five miniature magnetic sensors 24 can be used, with a maximum detection depth of 80mm.

[0054] Combination Figure 5As shown, the precision seeder has a tractor at its front for towing it. A controller 22 is located inside the tractor and is connected to a multi-dimensional high-precision magnetic sensing module 20 via a signal line. This controller processes the magnetic induction intensity information transmitted by the magnetic sensing module 20. A GPS wireless speed measuring device 21 is located on the top of the tractor. A human-machine interface display terminal 23 is also located inside the tractor and is connected to the controller 22. The human-machine interface device 23 is installed in the tractor cab and is connected to the controller 22 via a wireless serial communication module. The human-machine interface device 23 is used to input soil information of the seeded plot and to display and store real-time information such as seeding spacing, seeding depth, and operating speed sent by the controller. The GPS wireless speed measuring device 4 includes a GPS antenna and a speed data transmission plug. The GPS wireless speed measuring device can acquire the real-time forward speed of the seeder using the GPS antenna 401. It connects to the speed receiving plug of the controller 22 via the speed data transmission plug 402, transmitting the speed signal to the controller 22. The controller 22 is a PLC controller or a microcontroller. Alternatively, the GPS wireless speed measuring device can also be a GPS receiver, a device mounted on the top of the tractor for receiving GPS information. After receiving the GPS information, the speed can be deciphered from it. It should be noted that any parts not detailed in this application are prior art.

[0055] The in-situ detection method for seeding particle size and depth based on a magnetic field induction-based in-situ detection device includes the following steps:

[0056] S1. Coat the seeds to be sown with iron powder to obtain iron powder coated seeds.

[0057] In step S1, ferrite powder or neodymium iron boron powder is used as the coating material, and a coating film-forming agent is used as the binder to coat the seeds with iron powder to obtain iron powder coated seeds.

[0058] S2. Magnetize the iron powder-coated seeds to obtain magnetized seeds.

[0059] Iron powder-coated seeds were magnetized using a magnetizer to obtain magnetized seeds with a surface magnetic induction intensity of 5-7 mT.

[0060] S3. Sowing magnetized seeds using a precision seeder. Magnetized seeds are placed in the seed box 5 of the precision seeder. The controller 22 is activated to control the electric push rod 15 to reach the target stroke, pressing the cutting shovel 19 into the seed furrow to the working depth. The multi-dimensional high-precision magnetic sensing module 20 located on the inner wall of the cutting plate 191 is activated. The GPS wireless speed measuring device 4 is activated to receive the seeder's operating speed in real time. During sowing, the magnetized seeds fall into the seed guide tube 8 through the seed metering device 6, reaching the seed furrow along the inner wall of the seed guide tube 8. The covering and pressing wheel 11 covers and presses the seed furrow. The cutting shovel 19 moves along the seed furrow with the seeder. When the cutting shovel 19 passes the seed, the multi-dimensional high-precision magnetic sensing module 20 measures the magnetic induction intensity of the magnetized seed and sends the magnetic induction intensity information to the controller 22 via a communication line.

[0061] S4. Calculate the seed spacing:

[0062] The controller 22 receives magnetic induction intensity information from multiple miniature magnetic sensors 24, and determines whether the collected magnetic induction intensity information comes from magnetized seeds. Specifically, the controller 22 includes a timer. If yes, the count is incremented by 1 and the timer is started; otherwise, it waits to receive the next magnetic induction intensity information. When the second magnetic induction intensity is received, the timer value is retrieved, the time interval Δt between two adjacent seed signals is calculated, the count variable is set to 1, and the timer is cleared to 0. The seed spacing is calculated using the following formula:

[0063]

[0064] In the formula, s is the seed spacing in cm, Δt is the time interval between detecting two adjacent seeds in s, and v is the operating speed of the precision seeder in km / h.

[0065] S5. Calculate the sowing depth:

[0066] The controller 22 receives magnetic induction intensity information from multiple miniature magnetic sensors 24, compares the magnitudes of the magnetic induction intensity information from the multiple magnetic induction intensity information, determines the maximum magnetic induction intensity, and calculates the sowing depth using the following formula:

[0067]

[0068] In the formula, B is the magnetic flux density T, μ0 is the free permeability T·m / A, and μ r T is the relative magnetic permeability of the soil, and m is the magnetic dipole moment, A·m. 2 , denoted as the unit vector pointing from the magnetic seed to the miniature magnetic sensor 24, and r is the distance m from the magnetized seed to the miniature magnetic sensor 24.

[0069] In step S4, determining whether the collected magnetic induction intensity information comes from the magnetization seed includes the following steps:

[0070] S41. Select soil samples from the sowing area, prepare soil samples with different moisture contents, soil organic matter content, and pH values. Place magnetized seeds in soil samples with different depths and soil properties, and use a magnetic induction sensor to measure the magnetic induction intensity of the seeds at different soil properties and depths. Establish a mathematical model between soil properties, detection distance, and magnetic induction intensity, as shown below:

[0071] B = f (SMC, SOM, r) (3)

[0072] In the formula, B is the magnetic induction intensity T, SMC is the soil moisture content, SOM is the soil organic matter content g / kg, and r is the distance m from the magnetized seed to the micro magnetic sensor 24.

[0073] S42. Before sowing, the soil properties of the area to be sown are measured to obtain the distance D between the magnetized seed and the micro magnetic sensor 24, which is between [D1, D2]. The soil properties and the distance D range are input into the prediction model to obtain the distribution range of the magnetic induction intensity of the magnetized seed [B1, B2].

[0074] S43. If the measured magnetic induction intensity of a magnetized seed is between [B1, B2], it is considered a magnetized seed; otherwise, it is considered a magnetic foreign object.

[0075] The soil properties of the sowing area are measured, and the distance D between the magnetic seeds and the miniature magnetic sensor 22 is determined based on the sowing agronomy of the crop and the size of the cutting shovel. The width of the seed furrow is W1, the distance between the two cutting plates 191 is W2, and the outer shell thickness of the multi-dimensional high-precision magnetic sensing module 20 is W3. Therefore, Taking corn as an example, the width of the cutting shovel 19 is 100mm, the thickness of the cutting plate 191 is 25mm, the distance W2 between the two cutting plates 191 is 50mm, the outer shell thickness of the multi-dimensional high-precision magnetic sensing module 20 is 5mm, and the width of the planting furrow during corn planting is 30mm. That is, the detection distance D between the magnetized seed and the miniature magnetic sensor 22 is between [15, 30]. Figure 10 As shown.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A device for in-situ detection of seed spacing and seeding depth based on magnetic field induction, characterized in that, The system includes a mounting base (13) at the rear end of the precision seeder, a vertical rod (14) on the mounting base (13), and a cutting shovel (19) at the lower end of the vertical rod (14). The cutting shovel (19) has two cutting plates (191) arranged opposite each other. The two cutting plates (191) are respectively provided with multi-dimensional high-precision magnetic sensing modules (20) for detecting magnetic induction intensity information. The system also includes a controller (22) and a GPS wireless speed measuring device (21). The GPS wireless speed measuring device (21) is used to measure the real-time operating speed of the precision seeder. The controller (22) is electrically connected to the GPS wireless speed measuring device (21) and the multi-dimensional high-precision magnetic sensing module (20). The multi-dimensional high-precision magnetic sensing module (20) includes a housing and multiple miniature magnetic sensors (24) arranged in a rectangular array inside the housing. The controller (22) receives magnetic induction intensity information from multiple miniature magnetic sensors (24), compares the magnitudes of the magnetic induction intensity information from the multiple magnetic induction intensity information, determines the maximum magnetic induction intensity, and substitutes the maximum magnetic induction intensity into the following formula to calculate the sowing depth: In the formula, B is the magnetic flux density in tons (T), μ0 is the free permeability in tons (T·m / A), and μ r The relative magnetic permeability of the soil is expressed in T·m / A, where m is the magnetic dipole moment in A·m. 2 , denoted as the unit vector from the magnetic seed to the miniature magnetic sensor (24), and r is the distance from the magnetized seed to the miniature magnetic sensor (24) in meters.

2. The in-situ detection device for seeding spacing and depth based on magnetic field induction according to claim 1, characterized in that, The precision seeder is equipped with a tractor at the front end for towing the precision seeder. The controller (22) is located inside the tractor. The GPS wireless speed measuring device (21) is located on the top of the tractor. The tractor is also equipped with a human-machine interaction display terminal (23), which is connected to the controller (22).

3. The in-situ detection device for seed spacing and seeding depth based on magnetic field induction according to claim 1, characterized in that, The mounting base (13) is hinged to the rear end of the precision seeder. A parallelogram linkage mechanism is provided on the vertical rod (14). The rear end of the parallelogram linkage mechanism is provided with depth limiting wheels on both sides of the cutting shovel (19). The lower end of the depth limiting wheel is flush with the top of the cutting shovel (19).

4. The in-situ detection device for seeding spacing and depth based on magnetic field induction according to claim 1, characterized in that, A horizontal plate (141) is provided on the vertical rod (14), and an electric push rod (15) is provided between the horizontal plate (141) and the upper end of the cutting shovel (19).

5. The method for in-situ detection of seed spacing and seeding depth using the magnetic field induction-based in-situ detection device according to claim 1, comprising the following steps: S1. Coat the seeds to be sown with iron powder to obtain iron powder coated seeds; S2. Magnetize the iron powder-coated seeds to obtain magnetized seeds; S3. Sow the magnetized seeds using a precision seeder; S4. Calculate the seed spacing: The controller (22) receives magnetic induction intensity information from multiple miniature magnetic sensors (24), determines whether the collected magnetic induction intensity information comes from magnetized seeds, increments the counter by 1 and starts the timer if yes, waits to receive the next magnetic induction intensity information if no, and when the second magnetic induction intensity is received, it retrieves the timer value, calculates the time interval Δt between two adjacent seed signals, sets the counter variable to 1, clears the timer to 0, and calculates the seed spacing using the following formula: In the formula, s is the seed spacing in cm, Δt is the time interval between detecting two adjacent seeds in seconds, and v is the operating speed of the precision seeder in km / h. S5. Calculate the sowing depth: The controller (22) receives magnetic induction intensity information from multiple miniature magnetic sensors (24), compares the magnitudes of the magnetic induction intensity information from the multiple magnetic induction intensity information, determines the maximum magnetic induction intensity, and substitutes the maximum magnetic induction intensity into the following formula to calculate the sowing depth: In the formula, B is the magnetic flux density in tons (T), μ0 is the free permeability in tons (T·m / A), and μ r The relative magnetic permeability of the soil is expressed in T·m / A, where m is the magnetic dipole moment in A·m. 2 , denoted as the unit vector from the magnetic seed to the miniature magnetic sensor (24), and r is the distance from the magnetized seed to the miniature magnetic sensor (24) in meters.

6. In the method for in-situ detection of seed spacing and seed depth using the in-situ detection device for seed spacing and seed depth based on magnetic field induction as described in claim 5, in step S1, ferrite powder or neodymium iron boron powder is used as the coating material, and a coating film-forming agent is used as the binder to coat the seeds with iron powder to obtain iron powder coated seeds.

7. In the method for in-situ detection of seed spacing and seed depth using the in-situ detection device based on magnetic field induction according to claim 5, in step S2, the iron powder coated seeds are magnetized using a magnetizer to obtain magnetized seeds, and the magnetic induction intensity on the surface of the magnetized seeds is 5-7 mT.

8. The method for in-situ detection of seed spacing and seed depth using the in-situ detection device based on magnetic field induction according to claim 5, wherein step S4, determining whether the collected magnetic induction intensity information comes from magnetized seeds, includes the following steps: S41. Select soil samples from the sowing area, prepare soil samples with different moisture contents, soil organic matter content, and pH values. Place magnetized seeds in soil samples with different depths and soil properties, and use a magnetic induction sensor to measure the magnetic induction intensity of the seeds at different soil properties and depths. Establish a mathematical model between soil properties, detection distance, and magnetic induction intensity, as shown below: B = f(SMC, SOM, r) (3) In the formula, B is the magnetic induction intensity in T, SMC is the soil moisture content, SOM is the soil organic matter content in g / kg, and r is the distance from the magnetized seed to the micro magnetic sensor (24) in m. S42. Before sowing, the soil properties of the area to be sown are measured to obtain the distance D between the magnetized seed and the micro magnetic sensor (24) in the range of [D1,D2]. The soil properties and the distance D range are input into the prediction model to obtain the distribution range of the magnetic induction intensity of the magnetized seed in the range of [B1,B2]. S43. If the measured magnetic induction intensity of a magnetized seed is between [B1, B2], it is considered a magnetized seed; otherwise, it is considered a magnetic foreign object.

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