A multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradient

Abstract

The utility model discloses a kind of multilayer profile soil greenhouse gas observation devices that can simulate hydrothermal gradient, including transparent culture cylinder and gradient temperature control component, the transparent culture cylinder is filled with soil column, at least two stratified sampling ports are opened on the lateral wall of the transparent culture cylinder along its height direction, each The stratified sampling port is connected with sampling assembly, the top of the transparent culture cylinder is equipped with top cover unit, the top cover unit has water inlet, the gradient temperature control component is attached with the lateral wall of the transparent culture cylinder, the bottom of the transparent culture cylinder is connected with the bottom plate unit with electronic load cell.The utility model can simulate the hydrothermal environment of different soil layers under indoor conditions accurately, real-time acquisition gas concentration and environmental parameters of each depth, realize the multidimensional dynamic observation to soil greenhouse gas generation, migration and emission process.

Description

Technical Field

[0001] This invention belongs to the field of soil greenhouse gas observation technology, and particularly relates to a multi-layer profile soil greenhouse gas observation device that can simulate hydrothermal gradient. Background Technology

[0002] Soil greenhouse gas (CO2, N2O, CH4) emissions are an important part of global climate change and agricultural carbon and nitrogen cycle research. The emission process is jointly regulated by multiple factors such as soil temperature, moisture, aeration and microbial activity. In order to quantitatively analyze the generation and release mechanisms of soil greenhouse gases under different environmental conditions, static chambers, closed culture tanks or flux monitoring systems are widely used in scientific research and engineering practice for measurement. However, the applicant found that existing devices generally have the following shortcomings: First, the observation level is singular and cannot reflect vertical differences. Currently, most soil greenhouse gas measuring devices can only obtain overall flux data in the soil surface or enclosed space. They lack synchronous observation methods for the distribution of gas concentration in soil layers at different depths. The generation, diffusion and consumption processes of gases inside the soil have obvious vertical stratification characteristics. Measuring only the surface emissions is not enough to reveal the contribution of each layer and the potential gas production mechanism. Second, environmental factors are uncontrollable and it is difficult to simulate real gradients. Traditional devices mostly rely on natural environment or constant temperature culture conditions, which cannot achieve gradient control and dynamic adjustment of temperature and moisture. This results in single experimental conditions and poor repeatability. Especially in arid and semi-arid areas, the spatial heterogeneity of soil hydrothermal conditions is significant. The lack of a controllable simulation system limits the depth of mechanism research. Third, the sampling method is singular, and gas cross-contamination or disturbance between layers is easy. Existing profile gas sampling or buried pipe sampling methods are complicated to operate, which can easily damage the soil structure or cause gas cross-contamination between different layers, affecting the accuracy of gas concentration and spatial representativeness. Fourth, hydrothermal and microenvironment monitoring are not linked. Currently, most culture devices only have a single temperature control or humidification function, lacking synchronous monitoring and automatic recording of multiple parameters such as temperature, moisture, and redox potential, making it difficult to achieve real-time coupled analysis of hydrothermal conditions and gas changes. In other words, current technology lacks a comprehensive observation device that can simulate hydrothermal gradients and simultaneously acquire greenhouse gas concentrations and environmental parameters in soil at different depths under controlled indoor conditions. This deficiency severely restricts the vertical analysis of the soil greenhouse gas generation-transmission-release process and also limits the accuracy of agricultural emission reduction and ecological model parameterization research. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a multi-layer profile soil greenhouse gas observation device that can simulate the hydrothermal gradient. It can accurately simulate the hydrothermal environment of different soil layers under indoor conditions, collect gas concentrations and environmental parameters at each depth in real time, and realize multi-dimensional dynamic observation of the generation, migration and emission process of soil greenhouse gases.

[0004] The objective of this utility model is achieved through the following technical solution: A multi-layer profile soil greenhouse gas monitoring device capable of simulating hydrothermal gradients includes a transparent culture cylinder and a gradient temperature control component. The transparent culture cylinder is filled with a soil column. At least two stratified sampling ports are formed along the height direction on the side wall of the transparent culture cylinder. Each stratified sampling port is connected to a sampling component. A top cover unit is installed on the top of the transparent culture cylinder, and the top cover unit has a water inlet. The gradient temperature control component is attached to the side wall of the transparent culture cylinder. The bottom of the transparent culture cylinder is connected to a base plate unit with an electronic load cell.

[0005] In one embodiment, the gradient temperature control assembly includes a variable temperature ring and a heating belt. The heating belt is attached to the side wall of the transparent culture cylinder, and the variable temperature ring is wound around the bottom of the transparent culture cylinder on its wall to form a temperature gradient from bottom to top.

[0006] In one embodiment, the gradient temperature control assembly includes a variable temperature ring and a heating belt. The heating belt is attached to the side wall of the transparent culture cylinder, and the variable temperature ring is wound around the bottom of the transparent culture cylinder on its wall to form a temperature gradient from bottom to top.

[0007] In one embodiment, the sampler is a stainless steel sampling needle or a Teflon microporous sampling head.

[0008] In one embodiment, the top and bottom of the transparent culture tube are provided with flange interfaces for connecting the top cover unit and the bottom plate unit.

[0009] In one embodiment, the top cover unit is further provided with a main gas intake port and a gas mixing fan, the gas mixing fan being located between the gas intake port and the water inlet.

[0010] In one embodiment, the top cover unit is also provided with a temperature sensor socket and a gas exhaust valve.

[0011] In one embodiment, the gradient temperature control component further includes multiple environmental sensors disposed at different depths of the soil column.

[0012] In one embodiment, the base plate unit further includes a support base, the support base having an embedded heat-insulating pad layer that contacts the transparent culture cylinder.

[0013] In one embodiment, the bottom of the transparent culture tube is also provided with a percolate outlet, which is connected to a collection bottle via a drain pipe.

[0014] The beneficial effects of this utility model are as follows: (1) Compared with traditional devices that only measure the flux of the soil surface or the whole, this device can simultaneously obtain the pore gas concentration at different depths (such as 5cm, 15cm, 30cm, etc.) by opening multiple independent stratified sampling ports on the side wall of the transparent culture cylinder. This enables stratified, fixed-point and timed monitoring of greenhouse gases such as CO2, N2O and CH4, avoiding gas crosstalk between layers. The obtained profile data truly reflects the gas production layer and diffusion gradient, greatly improving the spatial resolution and scientific reliability of the observation.

[0015] (2) By setting up gradient temperature control components, water inlets on the top cover unit and base plate unit with electronic load elements, the vertical distribution of temperature and moisture content can be precisely controlled in an indoor environment. Different temperature (15~35℃) and moisture (40%–80% field capacity) gradients can be set according to experimental needs to realize various scenarios such as drought-humidity and cold-heat. Compared with natural environment observation, the system has high controllability and high repeatability, effectively reduces external interference, and makes the research results more comparable and verifiable.

[0016] (3) Sensor interfaces for temperature, water content, redox potential (Eh) are reserved at different depths. All parameters are recorded in real time through the data acquisition module and correspond precisely with the gas sampling time. This enables dynamic coupling analysis of "environmental factors-microbial processes-gas emissions" and provides experimental support for revealing the driving mechanism of greenhouse gases. (4) The transparent cylinder and detachable end cap are used for easy observation and cleaning; the multiple interfaces are sealed with standard threads and O-rings for easy installation and replacement. The unit can be used independently or multiple units can be connected in parallel to form a gradient experimental platform to meet different research needs. Compared with traditional soil culture tanks, this device has significant advantages in terms of ease of operation and experimental flexibility. (5) Through weighing feedback water replenishment and constant temperature control, the device can stably maintain the target hydrothermal state, so that the soil microenvironment is under repeatable conditions for a long time. Combined with analysis methods such as gas chromatography, it can simultaneously obtain multi-source data such as gas emission flux, profile concentration, leachate nutrients and environmental parameters, forming a complete information chain of greenhouse gas production-migration-release, which can significantly improve the quantitative level of experimental results and provide accurate parameters for greenhouse gas emission models and carbon and nitrogen cycle research. Attached Figure Description The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings. Wherein: Figure 1 A schematic diagram of the structure of this utility model is shown; Figure 2 A schematic diagram of the sampling component of this utility model is shown; Figure 3 A schematic diagram of the structure of the hydrothermal control component of this utility model is shown; Figure 4 A schematic diagram of the top cover unit of this utility model is shown; Figure 5 A schematic diagram of the base plate unit of this utility model is shown; In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.

[0017] Figure label: 1-Transparent culture cylinder, 2-Top cover unit, 3-Layered sampling port, 4-Hydrothermal control component, 5-Bottom plate unit, 6-Control unit, 7-Gas duct, 8-Airtight connector, 9-O-ring seal, 10-Sampler, 11-Connecting pipe, 12-Connecting valve, 13-Gas sampling port, 14-Water inlet, 15-Weighing sensor, 201-Main gas sampling port, 202-Gas mixing fan, 203-Sealing ring, 204-Top cover body, 401-Heating belt, 402-Heating ring, 501-Bearing base, 502-Loading unit, 503-Drain pipe, 504-Insulation pad. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] This invention provides a multi-layer profile soil greenhouse gas observation device that can simulate hydrothermal gradients, such as... Figures 1 to 5 As shown, the device includes a transparent culture cylinder 1 and a gradient temperature control assembly. The transparent culture cylinder 1 is filled with a soil column. At least two layered sampling ports 3 are opened on the side wall of the transparent culture cylinder 1 along its height direction. Each layered sampling port 3 is connected to a sampling assembly. A top cover unit 2 is installed on the top of the transparent culture cylinder 1. The top cover unit 2 has a water inlet 14. The gradient temperature control assembly is attached to the side wall of the transparent culture cylinder 1. The bottom of the transparent culture cylinder 1 is connected to a bottom plate unit 5 with an electronic load cell. Specifically, such as Figure 3 As shown, the gradient temperature control component includes a variable temperature ring and a heating belt 401. The heating belt 401 is attached to the side wall of the transparent culture cylinder 1. The variable temperature ring is wrapped around the bottom of the transparent culture cylinder 1 on its cylinder wall. The variable temperature ring can be a heating ring 402 or a cooling ring to form a temperature gradient from bottom to top. The hydrothermal control component 4 consists of the gradient temperature control component, the weighing sensor 15, and the water adding actuator. It should be noted that, in this embodiment, compared to traditional devices that only measure the flux of the soil surface or the overall soil, this device is placed vertically on the experimental platform and stabilized by a fixed support. Through multiple independent stratified sampling ports 3 opened on the side wall of the transparent culture cylinder 1, the pore gas concentration at different depths (e.g., 5cm, 15cm, 30cm, etc.) can be simultaneously acquired. This enables stratified, point-to-point, and timed monitoring of greenhouse gases such as CO2, N2O, and CH4, avoiding interlayer gas crosstalk. The obtained profile data accurately reflects the gas production layers and diffusion gradients, significantly improving the spatial resolution and scientific reliability of the observations. Simultaneously, through the set gradient temperature control components and the water inlet 14 opened on the top cover unit 2... The base plate unit 5, equipped with an electronic load cell, can precisely control the vertical distribution of temperature and moisture content in an indoor environment. Different temperature (15~35℃) and moisture (40%~80% field capacity) gradients can be set according to experimental needs to simulate various scenarios such as drought-humidity and cold-heat. Compared with natural environment observation, the system has high controllability and high repeatability, effectively reduces external interference, and makes the research results more comparable and verifiable. The inside of the cylinder can be filled with original or prepared soil to simulate different farmland conditions. The device can achieve precise control of environmental factors such as temperature and moisture in an indoor environment and simultaneously sample and analyze soil gases at different depths. In one embodiment, the transparent culture cylinder 1 is a cylindrical structure made of high-strength transparent acrylic material, with a height of 30-50cm, an inner diameter of 10-15cm, and a wall thickness of about 5-8mm. The inner wall of the cylinder is smooth, corrosion-resistant, and pressure-resistant. Flange interfaces are provided at the top and bottom for connection with the top cover unit 2 and the bottom plate unit 5. The cylinder wall has 3-4 layered sampling ports 3 opened in the vertical direction, located at 5cm, 15cm, 30cm from the bottom, respectively. Threaded joints or quick-connect joints are provided on the outside of the sampling ports for easy connection with the sampling components. The transparent culture cylinder 1 is used to contain soil samples, form a soil profile structure, and provide a real medium environment for gas generation and transmission. In one embodiment, such as Figure 2 As shown, the sampling assembly includes a sampler 10 and a gas delivery tube 7. The gas delivery tube 7 is connected to the sampling port. The sampler 10 is connected to the gas delivery tube 7 through an airtight connector 8. The end of the sampler 10 inserted into the soil column has a porous structure. The sampler 10 is inserted into the soil column for about 2-3 cm. The porous structure of the sampler 10 can uniformly collect pore gas in this layer. The gas sampling port 13 at the outer end is connected to the sampling bag or gas chromatograph through a connecting pipe 11. There is a connecting valve 12 between the connecting pipe 11 and the gas sampling port 13 to facilitate gas sampling control. Each interface uses a double O-ring seal 9 to prevent interlayer gas leakage. Through the sampling assembly, gas samples at different depths can be obtained simultaneously, realizing vertical profile observation of greenhouse gases such as CO2, N2O, and CH4. In one embodiment, the sampler 10 is a stainless steel sampling needle or a Teflon microporous sampling head; In one embodiment, such as Figure 4 As shown, the top cover unit 2 includes a top cover body 204 and a main gas sampling port 201 and a gas mixing fan 202 disposed on the top cover body 204. A water inlet 14 is also disposed on the top cover body 204. The gas mixing fan 202 is located between the main gas sampling port 201 and the water inlet 14. The main gas sampling port 201 is used to extract gas samples from the head space after a short period of closure to calculate the overall flux. The water inlet 14 is connected to a micro-injection pump or a burette, which can quantitatively replenish water to the soil surface. The gas mixing fan 202 is installed in the center of the cover and runs at low speed to ensure that the gas is mixed evenly in the head space. Furthermore, the top cover unit 2 is also equipped with a temperature sensor socket and a gas exhaust valve for easy sampling and gas pressure regulation; In one embodiment, the gradient temperature control component also includes multiple environmental sensors set at different depths of the soil column, such as temperature, volumetric water content and redox potential (Eh) probes, to achieve synchronous monitoring of multiple parameters. The temperature setting range is 10~40 ℃ with an error of no more than ±0.5 ℃. The mass inside the container is monitored by an electronic load cell, namely the load cell 502 at the bottom and the water inlet 14 at the top. Evaporation loss is calculated based on real-time mass changes. The preset water content level is maintained by automatic water injection, which can simulate the temperature and water content gradient caused by depth differences in natural soil and maintain long-term stable operation of the experiment. In one embodiment, such as Figure 5 As shown, the base plate unit 5 also includes a support base 501. The support base 501 is embedded with a heat-insulating pad 504 that contacts the transparent culture cylinder 1. The bottom of the transparent culture cylinder 1 is also provided with a percolate outlet. The percolate outlet is connected to a collection bottle through a drain pipe 503. The percolate outlet is connected to the collection bottle to collect dissolved organic carbon and inorganic nitrogen samples, while preventing water accumulation. The heat-insulating pad is embedded in the support base to prevent heat from being conducted outward and affecting gradient stability. In one embodiment, the control unit 6 adopts a microcontroller (MCU) or PLC system, which connects all sensors, electronic load cells and heating / water filling actuators to collect, display and record data in real time, and automatically adjust the heating and water filling frequency to achieve closed-loop control. In one embodiment, the device operates on the following principle: The original soil sample taken from the farmland or experimental area is placed into a transparent culture cylinder, and the layers are lightly pressed to maintain the natural density. Depending on the experimental needs, vegetable waste, straw or fertilizer can be mixed in. After filling, the top cover is installed and sealed. By setting the target temperature gradient (e.g., 30 ℃ for the bottom layer and 20 ℃ for the top layer) and moisture gradient (e.g., humid top layer, moderate middle layer, and dry bottom layer) by the control unit, the hydrothermal control component is activated and runs stably to the preset state. During the experiment, gas samples were extracted through the top main sampling port and each layer sampling port at set time intervals (such as 0, 10, 20, 30 min) for GC analysis. Temperature, water content and Eh data at each depth were recorded simultaneously. If necessary, water was added or the temperature was adjusted through the water inlet to maintain the set conditions. By calculating the gas concentration gradient and headspace flux at each depth, and combining this with changes in environmental factors, the generation rate, diffusion patterns, and control mechanisms of greenhouse gases at different depths were obtained.

[0020] It should be noted that the device uses a detachable transparent culture cylinder as its main body, with multiple independent sampling ports arranged vertically. A multi-hole sampler extracts pore gases at different depths, achieving precise stratified collection of greenhouse gases such as CO2, N2O, and CH4. Each sampling component uses O-rings to effectively prevent interlayer gas cross-contamination, improving the accuracy of profile measurements. The device integrates a bottom load cell and a top water supply unit, using weighing feedback to dynamically maintain soil moisture content. Simultaneously, a settable temperature gradient is formed by the bottom heating ring and the cylinder wall heating belt, thus constructing a hydrothermal dual-control system capable of accurately simulating natural scenarios of wet / dry and warm / cold distribution. Temperature, moisture content, and oxidation levels are pre-set at each depth. The device features a potential sensor interface and a microcontroller for synchronous acquisition of multiple parameters, automatic water replenishment, and closed-loop temperature control. A mixing fan and main sampling port are located at the top, allowing for gas mixing within the head space and measurement of the overall flux under sealed conditions. A leachate collection port at the bottom prevents water accumulation and collects dissolved samples. Compared to existing technologies, this device integrates multi-layer independent sampling, anti-cross-gas sealing, controllable hydrothermal gradient, and synchronous monitoring of environmental factors and gases, significantly improving experimental accuracy and repeatability. It is suitable for research on greenhouse gas emission mechanisms in farmland, vegetable waste return, and fertilization scenarios, possessing advantages such as reasonable structure, high functional integration, strong data coupling, and significant application value. In one embodiment, each sampling port 13 may also be equipped with an infrared gas sensor or a miniature gas analyzer to enable online monitoring; In one embodiment, a metal bracket with casters is also included, with the support base 501 mounted on the metal bracket for easy movement and adjustment within the laboratory.

[0021] In the description of this utility model, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] While specific embodiments of the present invention have been described herein with reference to them, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients, characterized in that, The device includes a transparent culture cylinder and a gradient temperature control assembly. The transparent culture cylinder is filled with a soil column. At least two stratified sampling ports are provided on the side wall of the transparent culture cylinder along its height direction. Each stratified sampling port is connected to a sampling assembly. A top cover unit is installed on the top of the transparent culture cylinder. The top cover unit has a water inlet. The gradient temperature control assembly is attached to the side wall of the transparent culture cylinder. The bottom of the transparent culture cylinder is connected to a base plate unit with an electronic load cell.

2. The multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients according to claim 1, characterized in that, The gradient temperature control component includes a variable temperature ring and a heating belt. The heating belt is attached to the side wall of the transparent culture cylinder, and the variable temperature ring is wrapped around the bottom of the transparent culture cylinder and its wall to form a temperature gradient from bottom to top.

3. The multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients according to claim 1, characterized in that, The sampling assembly includes a sampler and an air guide tube. The air guide tube is connected to the sampling port. The sampler is connected to the air guide tube through an airtight connector. The end of the sampler that is inserted into the soil column has a porous structure.

4. The multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients according to claim 3, characterized in that, The sampler is a stainless steel sampling needle or a Teflon microporous sampling head.

5. A multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients according to claim 1, characterized in that, The transparent culture cylinder is provided with flange interfaces at the top and bottom for connecting the top cover unit and the bottom plate unit.

6. A multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients according to claim 5, characterized in that, The top cover unit is also equipped with a main gas intake port and a gas mixing fan, with the gas mixing fan located between the gas intake port and the water inlet.

7. A multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients according to claim 1 or 6, characterized in that, The top cover unit is also equipped with a temperature sensor socket and a gas exhaust valve.

8. A multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients according to claim 1, characterized in that, The gradient temperature control component also includes multiple environmental sensors installed at different depths in the soil column.

9. A multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients according to claim 1, characterized in that, The base plate unit also includes a support base, which has an embedded heat-insulating pad layer that contacts the transparent culture cylinder.

10. A multi-layer profile soil greenhouse gas observation device capable of simulating hydrothermal gradients according to claim 1, characterized in that, The bottom of the transparent culture tube is also provided with a percolate outlet, which is connected to a collection bottle through a drain pipe.

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