Soil column test device and method for plant root zone micro-ecological simulation research

Abstract

The invention discloses a soil column test device and method for plant root zone micro-ecology simulation research. The soil column test device comprises a soil column test model module and a solution collection module. The soil column experimental model module comprises a soil filling container with an upper cover and a lower cover, a plant root simulation device, a simulated root exudate sampling device, a soil oxidation-reduction potential monitoring device and a gas collection device, and the solution collection module is used for collecting liquid in the simulation process. According to the device, the plant root simulating device, the root exudate simulating and sampling device, the soil oxidation-reduction state monitoring device and the gas and soil solution collecting device are integrated, so that comprehensive simulation and monitoring of multiple factors of a plant root zone are realized. The device is low in processing cost, convenient to use and easy to operate, all parts are detachable and reusable, multiple pieces of environmental parameter information can be obtained, and the device has important significance on plant root zone micro-ecology research.

Description

Technical Field

[0001] This invention relates to the field of soil and plant root zone microecology simulation technology, and more specifically to a soil column test device and method for plant root zone microecology simulation research. Background Technology

[0002] The rhizosphere microenvironment, a complex reaction zone composed of soil, roots, and microorganisms, is a key hub for material cycling and energy flow, and has become a research focus in botany, ecology, and environmental science. Plant root growth is complex, influenced not only by external environmental conditions such as soil moisture, but also by the metabolites secreted by roots at different growth stages, which affect the physicochemical properties of the rhizosphere soil and the mineralization and transformation of soil organic carbon. Previous studies on the rhizosphere heat zone typically employed the "root-shaking method" to directly collect soil samples from the plant's rhizosphere, or used rhizosphere ecological simulation devices. Rhizosphere simulation devices effectively overcome the limitations of complex rhizosphere environments and difficult soil sample collection in the field; they can also meet the needs of researching the impact of single or different root exudates on the ecological environment of the rhizosphere soil.

[0003] In the prior art, the utility model patent with authorization announcement number CN207264658U discloses a device for simulating plant roots and rhizosphere ecology, which realizes the simulation of root secretion process and cultivation of rhizosphere soil samples, and facilitates the collection of rhizosphere soil samples; the patent document with publication number CN118534091A proposes a rhizosphere ecology simulation device and a method for injecting simulated root secretions. By connecting an external air pump to a cylindrical soil storage container, a simplified rhizosphere ecology simulation device is constructed, reducing operating costs.

[0004] However, the existing devices and methods still have the following problems: (1) They are mainly for dryland soils and do not consider the impact of soil moisture on the microecology of plant root zones. Due to the limitations of device combination and ventilation holes, soil moisture regulation is not possible, especially the impact of simulated flooding environment on soil and microorganisms; (2) They lack gas collection devices and ignore the emission process of greenhouse gases in root zone soil under the joint action of plants and microorganisms; (3) They cannot collect soil solution samples, or the collection process is complicated and difficult to operate.

[0005] Therefore, how to provide a simulation testing device that is easy to operate and can meet different experimental needs is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a root zone micro-ecological simulation device that integrates soil moisture regulation, greenhouse gas collection and soil solution collection. It can effectively simulate the real soil moisture environment and plant root secretion function, obtain gas emissions and soil-related data in real time, and has high repeatability and flexibility, which can meet different experimental conditions and needs.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] Firstly, this invention provides a soil column test device for simulating the microecology of plant root zones, including a soil column test model module and a solution collection module;

[0009] The soil column experimental model module includes a soil filling container with a matching upper and lower cover. A plant root simulation device is installed inside the soil filling container. The plant root simulation device is connected to a simulated root exudate sampling device. The soil filling container is also connected to a soil redox potential monitoring device and a gas collection device.

[0010] The solution collection module includes a partition bracket and a collection bottle. The partition bracket is provided with a groove for matching and installing the bottom of the backfill container. The collection bottle is connected to the backfill container.

[0011] Preferably, the top cover is provided with a detection hole, a connection hole and a gas sampling hole to facilitate the connection and communication between the various functional components and the filling container.

[0012] Preferably, the simulated root exudate sampling device includes a sampling plastic tubing, a sampling connector, and a sampler;

[0013] The sample injector is connected to the sample injection plastic tubing via the sample injection connector, and the sample injection plastic tubing is connected to the plant root simulation device;

[0014] The sample injection plastic tubing passes through the connection hole on the top cover and is connected at both ends to the plant root simulation device and the sample injection connector, respectively, and the sample injection plastic tubing is relatively sealed to the connection hole.

[0015] Preferably, the plant root simulation device includes a simulated root permeation section and a simulated root extension tube connected to the top of the simulated root permeation section via a simulated root interface, the top of the simulated root extension tube being connected to the sample injection plastic tubing.

[0016] Preferably, the soil redox potential monitoring device includes an Eh probe and an Eh meter, the Eh probe and the Eh meter are connected by a wire, and the Eh probe is inserted into the backfill container.

[0017] Furthermore, the wire passes through the detection hole on the top cover, and the wire and the detection hole are relatively sealed.

[0018] Preferably, the gas collection device includes a Luer interface three-way valve, a syringe, and a pre-vacuumed glass gas collection tube; one end of the Luer interface three-way valve is connected to the backfill container via a rubber tube, and the other two ends are respectively connected to the syringe and the pre-vacuumed glass gas collection tube.

[0019] Furthermore, one end of the Luer interface three-way valve is connected to the backfill container through a rubber tube passing through the air sampling hole, and the rubber tube and the air sampling hole are relatively sealed.

[0020] Preferably, the filling container is a hollow cylinder, which can be made of PVC material. The upper cover and the lower cover are both equipped with sealing rings at the connection points with the filling container to increase the airtightness of the soil column.

[0021] Furthermore, the cylindrical soil filling container has an inner diameter of 800mm and a height of 300mm to meet the soil filling height (approximately 20cm) required in studies simulating farmland topsoil and to leave sufficient upper space for gas collection.

[0022] Preferably, the lower cover is provided with a drainage hole, the drainage hole is covered with a nylon membrane, and the collection bottle and the soil filling container are connected through the drainage hole.

[0023] Furthermore, the drainage hole diameter can be 7mm, and the nylon membrane pore diameter can be 25μm, to prevent soil particles from flowing out with the water flow.

[0024] Preferably, the collection bottle and the drainage hole are connected by a water guide pipe, and the water guide pipe is equipped with a two-way valve, which can control the collection time and frequency of the soil solution in real time.

[0025] Preferably, the partition bracket is made of transparent material and has an open structure at the bottom to facilitate observation of soil solution collection and quick replacement of the solution collection bottle; the groove is provided with a hole for the water guide pipe to pass through.

[0026] Furthermore, the partition bracket is made of transparent acrylic material, and the geometry of the groove is adapted to the outline of the lower cover to increase the stability of the device during the cultivation process, and the circular hole in the groove facilitates the passage of the water pipe.

[0027] This invention also provides a soil column test method for simulating the microecology of plant root zones, using the apparatus described above, and including the following steps:

[0028] S1. Assemble the filling container and the lower cover, fill the container with the test soil sample and adjust the moisture content to the predetermined value;

[0029] S2. Insert the relevant parts of the soil redox potential monitoring device and the plant root simulation device into the soil to a preset depth, connect the plant root simulation device with the simulated root exudate sampling device, and connect the gas collection device with the soil filling container.

[0030] S3. After tightening the filling container and the top cover, ensure airtightness;

[0031] S4. Install the assembled soil column experimental model module into the groove of the partition bracket, and connect the lower end of the filling container to the collection bottle;

[0032] S5. Load the pre-prepared simulated root exudate solution into the simulated root exudate injection device, and slowly push the solution into the device at the required flow rate for the experiment;

[0033] S6. Real-time monitoring of soil redox status using a soil redox potential monitoring device;

[0034] S7. The gas inside the backfill container is replaced or collected by a gas collection device, and the collection time and frequency of the soil solution are controlled in real time by controlling the opening and closing of the collection bottle.

[0035] S8. When collecting soil samples in a destructive manner, first unscrew the top cover, remove the soil redox potential monitoring device and the plant root simulation device from the soil, and use a hollow soil sampler with an inner diameter a few millimeters wider than the plant root simulation device to collect rhizosphere soil. Then, collect non-rhizosphere soil according to the experimental requirements.

[0036] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a soil column test device and method for plant root zone microecological simulation research, which has the following beneficial effects:

[0037] This device innovatively combines a cylindrical soil-filling container, simulated plant roots, and a simulated root exudate sampling device to realistically simulate the dynamic impact of root exudates on the rhizosphere microecology under different soil moisture conditions. This design not only improves the controllability of experimental conditions but also ensures the reliability and repeatability of experimental results.

[0038] This device integrates a soil redox potential monitoring device, a gas sampling device, and a soil solution collection device, enabling multi-dimensional research on soil carbon turnover processes. It can simultaneously acquire soil Eh values, greenhouse gas emission fluxes, and water and solute migration data, significantly improving the comprehensiveness and accuracy of the research data.

[0039] This device adopts a modular design, is easy to operate, and its components can be quickly disassembled and assembled, are reusable, and can be adjusted according to different experimental conditions and needs, which improves the flexibility of root zone microecological research experiments and better simulates real natural environmental conditions. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0042] Figure 2 This is a top view of the upper and lower covers of the soil filling container of the present invention;

[0043] Figure 3 This is a schematic diagram of the plant root simulation device and the simulated root exudate sampling device of the present invention.

[0044] Figure 4 This is a schematic diagram of the gas collection device of the present invention;

[0045] Figure 5 This is a top view of the partition bracket structure of the present invention;

[0046] In the diagram: 1. Soil column experimental model module; 11. Soil filling container; 12. Top cover; 121. Detection hole; 122. Connection hole; 123. Air intake hole; 124. Rubber hose; 13. Bottom cover; 131. Drainage hole; 132. Nylon membrane; 133. Water guide pipe; 134. Two-way valve; 14. Plant root simulation device; 141. Simulated root infiltration section; 142. Simulated root interface; 143. Simulated root extension pipe; 15. Model 151. Root exudate sampling device; 152. Sampling plastic tubing; 153. Sampling connector; 154. Sampler; 16. Soil redox potential monitoring device; 161. Eh probe; 162. Eh meter; 17. Gas collection device; 171. Luer interface three-way valve; 172. Syringe; 173. Pre-vacuumed glass gas collection tube; 2. Solution collection module; 21. Partition bracket; 211. Groove; 22. Collection bottle. Detailed Implementation

[0047] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] like Figure 1-5 As shown, the soil column test device for simulating the microecology of plant root zones includes a soil column test model module 1 and a solution collection module 2.

[0050] The soil column experimental model module 1 includes a cylindrical soil filling container 11, which has a matching upper cover 12 and lower cover 13. A plant root simulation device 14 is installed inside the soil filling container 11. The plant root simulation device 14 is connected to a simulated root exudate sampling device 15. The soil filling container 11 is also connected to a soil redox potential monitoring device 16 and a gas collection device 17.

[0051] The solution collection module 2 includes a partition bracket 21 and a collection bottle 22. The partition bracket 21 is provided with a groove 211 for matching installation at the bottom of the backfill container 11. The collection bottle 22 is connected to the backfill container 11.

[0052] The upper cover 12 is provided with a detection hole 121, a connection hole 122, and a gas sampling hole 123. The diameter of the detection hole 121 is 16mm, the diameter of the connection hole 122 is 4mm, and the diameter of the gas sampling hole 123 is 7mm. In the specific implementation process, the diameter and number of functional interfaces can be further adjusted according to the changes in the monitoring index requirements to meet the wiring and passage requirements of each device module. This embodiment only lists one case.

[0053] The simulated root exudate sampling device 15 includes a sampling plastic tubing 151, a sampling connector 152, and a sampler 153;

[0054] The injector 153 is connected to the injection plastic tubing 151 via the injection connector 152, and the injection plastic tubing 151 is connected to the plant root simulation device 14;

[0055] The sample injection plastic tubing 151 passes through the connection hole 122 on the upper cover 12 and is connected to the plant root simulation device 14 and the sample injection connector 152 at both ends respectively. After the sample injection plastic tubing 151 and the connection hole 122 are assembled, a sealing material is used to achieve a relative seal.

[0056] The plant root simulation device 14 includes a simulated root penetration section 141 and a simulated root extension tube 143 connected to the top of the simulated root penetration section 141 via a simulated root interface 142. The top of the simulated root extension tube 143 is connected to the sample injection plastic tubing 151.

[0057] In this embodiment, the simulated root penetration section 141 is made of a hydrophilic porous polyester material with a length of 10cm, an outer diameter of 2.5mm, and an average pore size of 0.15μm, which can diffuse the simulated root exudate solution at a controllable rate and release it evenly into the soil.

[0058] The soil redox potential monitoring device 16 includes an Eh probe 161 and an Eh meter 162. The Eh probe 161 and the Eh meter 162 are connected by a wire. The Eh probe 161 is inserted into the backfill container 11.

[0059] The wire passes through the detection hole 121 on the upper cover 12, and the wire and the detection hole 121 are relatively sealed with a sealing material after assembly;

[0060] The gas collection device 17 includes a Luer interface three-way valve 171, a syringe 172, and a pre-vacuumed glass gas collection tube 173; one end of the Luer interface three-way valve 171 is connected to the backfill container 11, and the other two ends are respectively connected to the syringe 172 and the pre-vacuumed glass gas collection tube 173.

[0061] One end of the Luer interface three-way valve 171 is connected to the backfill container 11 through a rubber tube 124 passing through the air sampling hole 123. After the rubber tube 124 and the air sampling hole 123 are assembled, a sealing material is used to achieve a relative seal.

[0062] The filling container 11 is a hollow cylinder, which can be made of PVC material. In this embodiment, the cylindrical filling container 11 is a hollow cylinder made of PVC material, with an inner diameter of 800mm and a height of 300mm, in order to meet the filling height requirement (about 20cm) and leave enough space at the top for gas collection. The upper cover 12 and the lower cover 13 are both equipped with sealing rings at the connection points with the filling container 11.

[0063] The lower cover 13 is provided with a drainage hole 131, and the drainage hole 131 is covered with a nylon membrane 132. The collection bottle 22 and the filling container 11 are connected through the drainage hole 131. The diameter of the drainage hole 131 can be 7 mm, and the diameter of the nylon membrane 132 is 25 μm.

[0064] The collection bottle 22 is connected to the drain hole 131 by a water guide pipe 133, and a two-way valve 134 with a switch is provided on the water guide pipe 133.

[0065] The partition bracket 21 is made of transparent material, and the groove 211 is provided with a hole for the water guide pipe 133 to pass through;

[0066] In this embodiment, the inner diameter of the groove 211 is 104mm and the depth is 25mm. Its geometric dimensions are adapted to the outer contour of the lower cover 13. Nine grooves 211 are provided on the partition bracket 21, arranged in a matrix of three rows and three columns. The inner diameter of the hole through which the water guide pipe 133 passes is 10mm, and the hole and the water guide pipe 133 are relatively sealed.

[0067] The partition bracket 21 is made of 4mm thick transparent acrylic sheet with a bending strength ≥50MPa, which can meet the load-bearing requirements of multi-soil column parallel experiments. The lower part of the partition bracket 21 has an open structure, which makes it easy for the experimenters to observe the collection status of the soil solution in real time and can realize the quick replacement operation of the collection bottle 22.

[0068] Those skilled in the art will understand that the size of the partition bracket 21 and the number of grooves 211 can be expanded into an N×M matrix (N and M are positive integers), and the number of supporting soil column experimental model modules 1 can be adjusted accordingly to meet the needs of parallel experiments of different scales.

[0069] The specific method of using the soil column test device disclosed above for plant rhizosphere microecological simulation research is as follows:

[0070] S1. Tightly assemble the cylindrical filling container 11 and the lower cover 13, close the two-way valve 134 of the water pipe 133, then fill the container with the test soil sample and adjust the moisture content to the predetermined value.

[0071] S2. Connect the Eh probe 161 to the terminal device Eh meter 162 via wires, and nest the simulated root exudate sampling device 15 to the top of the plant root simulation device 14 to confirm that a sealed fluid channel is formed; seal the first port of the Luer interface three-way valve 171 to the upper end of the rubber tube 124, connect the second port to the syringe 172, and detachably connect the third port to the pre-vacuumed glass gas sampling tube 173 to form a multi-channel gas transmission system;

[0072] S3. Insert the Eh probe 161 vertically into the soil through the probe hole 121 of the upper cover 12 to the preset monitoring depth; pass the pre-assembled plant root simulation device 14 and simulated root exudate sampling device 15 through the connection hole 122, so that the simulated root penetration section 141 is completely buried in the soil and the simulated root interface 142 is flush with the soil surface; connect the gas collection device 17 to the gas collection hole 123 through the rubber tube 124 to achieve airtight connection;

[0073] S4. Tightly assemble the cylindrical soil filling container 11 with the top cover 12, and seal the detection hole 121, connection hole 122 and gas sampling hole 123 with sealing material;

[0074] S5. Install the assembled soil column experimental model module 1 into the groove 211 of the partition bracket 21, and pass the water pipe 133 through the circular hole of the groove 211, with its lower end connected to the collection bottle 22.

[0075] S6. Load the pre-prepared simulated root exudate solution into the injector 153, and slowly push the solution into the device at the required flow rate for the experiment;

[0076] S7. The soil redox state is monitored in real time through the Eh probe 161 and the external terminal device Eh meter 162;

[0077] S8. By adjusting the valve opening and closing state of the Luer interface three-way valve 171, selectively perform the following operations: a. Gas replacement mode: open the syringe 172 passage and replace the gas in the soil column device by reciprocating injection; b. Gas collection mode: switch to the glass gas collection tube 173 passage and use negative pressure to quantitatively collect the target gas in the soil column device into the pre-vacuumed glass gas collection tube 173.

[0078] S9. By adjusting the valve size and on / off state of the two-way valve 134, the collection time and frequency of soil solution can be controlled in real time;

[0079] S10. When collecting soil samples in a destructive manner, first unscrew the top cover 12, remove the Eh probe 161 and the plant root simulation device 14 from the soil, and use a hollow soil sampler with an inner diameter several millimeters wider than the plant root simulation device 14 to collect rhizosphere soil. Then, collect non-rhizosphere soil according to the experimental requirements.

[0080] In summary, the soil column test device disclosed in this application for simulating the microecological environment of plant rhizosphere can accurately simulate the microecological environment of plant rhizosphere, realize the controllable injection of root exudates, dynamic collection of soil solution, real-time monitoring of redox potential and precise collection of root zone gas, and provide an efficient and reliable experimental platform for the study of plant rhizosphere microecology.

[0081] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A soil column test device for simulating the microecology of plant rhizospheres, characterized in that, It includes a soil column experimental model module (1) and a solution collection module (2); The soil column experimental model module (1) includes a soil filling container (11), which has a matching upper cover (12) and lower cover (13). A plant root simulation device (14) is installed inside the soil filling container (11), which is connected to a simulated root exudate injection device (15). The soil filling container (11) is also connected to a soil redox potential monitoring device (16) and a gas collection device (17). The solution collection module (2) includes a partition bracket (21) and a collection bottle (22). The partition bracket (21) is provided with a groove (211) for matching installation at the bottom of the backfill container (11). The collection bottle (22) is connected to the backfill container (11).

2. The soil column test device for simulating the microecology of plant root zones according to claim 1, characterized in that, The simulated root exudate sampling device (15) includes a sampling plastic tubing (151), a sampling connector (152), and a sampler (153); The injector (153) is connected to the injection plastic tubing (151) via the injection connector (152), and the injection plastic tubing (151) is connected to the plant root simulation device (14).

3. The soil column test device for simulating the microecology of plant root zones according to claim 2, characterized in that, The plant root simulation device (14) includes a simulated root penetration section (141) and a simulated root extension tube (143) connected to the top of the simulated root penetration section (141) via a simulated root interface (142). The top of the simulated root extension tube (143) is connected to the sample injection plastic tubing (151).

4. The soil column test device for simulating the microecology of plant root zones according to claim 1, characterized in that, The soil redox potential monitoring device (16) includes an Eh probe (161) and an Eh meter (162). The Eh probe (161) and the Eh meter (162) are connected by a wire. The Eh probe (161) is inserted into the backfill container (11).

5. A soil column test device for simulating the microecology of plant root zones according to claim 1, characterized in that, The gas collection device (17) includes a Luer interface three-way valve (171), a syringe (172), and a pre-vacuumed glass gas collection tube (173); one end of the Luer interface three-way valve (171) is connected to the backfill container (11) through a rubber tube (124), and the other two ends are connected to the syringe (172) and the pre-vacuumed glass gas collection tube (173), respectively.

6. A soil column test device for simulating the microecology of plant root zones according to claim 1, characterized in that, The filling container (11) is a hollow cylinder, and the upper cover (12) and the lower cover (13) are both equipped with sealing rings at the connection points with the filling container (11).

7. A soil column test device for simulating the microecology of plant root zones according to claim 1, characterized in that, The lower cover (13) is provided with a drainage hole (131), and the drainage hole (131) is covered with a nylon membrane (132). The collection bottle (22) and the filling container (11) are connected through the drainage hole (131).

8. A soil column test device for simulating the microecology of plant root zones according to claim 7, characterized in that, The collection bottle (22) is connected to the drain hole (131) by a water guide pipe (133), and a two-way valve (134) is provided on the water guide pipe (133).

9. A soil column test device for simulating the microecology of plant root zones according to claim 8, characterized in that, The partition bracket (21) is made of transparent material and has an open structure at the bottom. The groove (211) has a hole for the water pipe (133) to pass through.

10. A soil column test method for simulating the microecology of plant rhizosphere, characterized in that, The apparatus according to any one of claims 1-9 comprises the following steps: S1. Assemble the filling container (11) and the lower cover (13), fill the container with the test soil sample and adjust the moisture content to the predetermined value; S2. Insert the relevant parts of the soil redox potential monitoring device (16) and plant root simulation device (14) into the soil to a preset depth, connect the plant root simulation device (14) with the simulated root exudate sampling device (15), and connect the gas collection device (17) with the soil filling container (11). S3. After tightening and assembling the backfill container (11) and the top cover (12), ensure airtightness; S4. Install the assembled soil column experimental model module (1) into the groove (211) of the partition bracket (21), and connect the lower end of the filling container (11) to the collection bottle (22); S5. Load the pre-prepared simulated root exudate solution into the simulated root exudate injection device (15), and slowly push the solution into the device according to the required flow rate for the experiment; S6. The soil redox potential monitoring device (16) is used to monitor the soil redox state in real time; S7. The gas in the backfill container (11) is replaced or collected by the gas collection device (17), and the collection time and frequency of the soil solution are controlled in real time by controlling the switch of the collection bottle (22). S8. When collecting soil samples in a destructive manner, first unscrew the top cover (12), remove the soil redox potential monitoring device (16) and the plant root simulation device (14) from the soil, and use a hollow soil sampler with an inner diameter a few millimeters wider than the plant root simulation device (14) to collect rhizosphere soil. Then collect non-rhizosphere soil according to the experimental requirements.

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