Multi-point synchronous diffusion type soil organic carbon stability measuring system

Abstract

Belonging to the technical field of soil organic carbon determination, the invention discloses a multi-point synchronous diffusion type soil organic carbon stability determination system, which comprises: at least one soil breathing chamber for covering a to-be-measured soil or culture container to form a gas collection space; the at least one CO2 sensor is arranged in the soil breathing chamber, is communicated with the gas collecting space and is used for detecting the CO2 concentration in the gas collecting space; by designing the special field soil breathing chamber base and the indoor soil breathing chamber base, the same set of core sensing and collecting system can be seamlessly adapted to the natural soil surface and the laboratory standard container. It is ensured that an indoor control experiment and field in-situ observation can adopt identical measurement standards and equipment, the consistency and comparability of research data are improved, and experiment configuration is simplified.

Description

Technical Field

[0001] This invention relates to the field of soil organic carbon determination technology, specifically a multi-point synchronous diffusion soil organic carbon stability determination system. Background Technology

[0002] Soil organic carbon is a core component of the global carbon cycle. Its stability and turnover dynamics directly affect the carbon source / sink functions of terrestrial ecosystems and have a crucial impact on global climate change. Therefore, high-precision and high-efficiency monitoring of soil respiration flux is a fundamental technical requirement for assessing soil organic carbon stability and predicting ecosystem carbon balance.

[0003] Currently, the measurement of soil respiration both domestically and internationally mainly relies on soil respiration measurement systems based on infrared gas analysis technology. These mainstream systems typically consist of three main parts: a control module, a gas analysis module, and a sampling module. Their basic principle is pump-assisted sampling, where a pump continuously draws the gas accumulated in the respiration chamber to the gas analysis module for CO2 concentration measurement. The soil respiration flux is then calculated based on the gas flow rate, concentration changes, and the area of ​​the respiration chamber.

[0004] Although the aforementioned technologies have been widely adopted, those skilled in the art recognize in practice that existing solutions still have unresolved shortcomings, particularly when addressing the needs of multi-scenario, long-term, and high spatial resolution system observations. Their application scenarios are limited, making them incompatible with both indoor and outdoor observations. Most existing commercial systems are designed for in-situ field observations, and their respiration chamber structures and power supply schemes are difficult to directly adapt to controlled culture experiments in the laboratory. Conversely, the static alkali absorption method or small airtight chamber method commonly used in indoor cultures cannot be used in the field. This scenario fragmentation prevents the use of the same standards and equipment to obtain comparable indoor and field data for the same research project, affecting the consistency and efficiency of the research.

[0005] Furthermore, pump-assisted sampling relies on a gas pump to maintain a constant flow rate in the gas path. Pressure fluctuations generated by the pump's operation can disrupt gas exchange in soil pores, introducing systematic errors. More importantly, the gas pump is the main energy-consuming component of the system, and its continuous operation results in enormous power consumption, severely limiting the system's ability to conduct long-term, continuous, unattended monitoring in the field without mains power. This often necessitates the use of large batteries or frequent power supply replacements, increasing observation costs and operational complexity. Traditional equipment is mostly single-channel or limited-channel designed, and in experimental designs requiring spatial repetition or multi-processing comparisons, it can only be achieved through serial measurements or the deployment of multiple independent devices. Serial measurements lead to time asynchrony of data from different locations, making it impossible to capture the true respiratory response under the same environmental driving factors; deploying multiple devices is costly and cumbersome for data integration. Therefore, existing technologies are insufficient to meet the growing demand in ecological research for high-precision, multi-location, long-term synchronous continuous observation.

[0006] Therefore, we propose a multi-point synchronous diffusion soil organic carbon stability measurement system to alleviate or solve the above problems.

[0007] The information disclosed above in this background section is only for enhancing the understanding of the background section of this invention, and therefore may include prior art that is not known to those skilled in the art. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a multi-point synchronous diffusion soil organic carbon stability measurement system, which solves the problems in existing technologies such as difficulty in adapting to multiple indoor and outdoor scenarios, low power consumption for long-term continuous monitoring, and multi-point synchronous high-precision data acquisition.

[0009] To achieve the above objectives, the present invention provides a multi-point synchronous diffusion soil organic carbon stability measurement system, comprising:

[0010] At least one soil breathing chamber is used to cover the soil to be tested or the culture container to form a gas collection space;

[0011] At least one CO2 sensor is installed in the soil breathing chamber and communicates with the gas collection space to detect the CO2 concentration in the gas collection space;

[0012] The data acquisition controller communicates with the CO2 sensor to synchronously acquire and process CO2 concentration data from multiple measurement points.

[0013] The power supply unit provides power to the CO2 sensor and the data acquisition controller.

[0014] A data display, which is communicatively connected to the data acquisition controller, is used to display and / or export the CO2 concentration data in real time;

[0015] In this system, the gas in the gas collection space exchanges with the gas on the surface of the soil to be tested through natural diffusion, and the system measures the soil organic carbon stability by monitoring the change in CO2 concentration in the gas collection space.

[0016] Preferably, the soil breathing chamber includes a field soil breathing chamber for field measurements and / or an indoor soil breathing chamber for indoor measurements;

[0017] The field soil breathing chamber includes a first base that can be inserted into or pressed into natural soil and a first cavity that can be sealed to the first base;

[0018] The indoor soil breathing chamber includes a second base for sealing a standard culture container and a second cavity that is sealably connected to the second base.

[0019] Preferably, the first base has a conical spike for inserting into the soil on the side away from the first cavity.

[0020] Preferably, the second base is provided with a sealing ring that matches the port of the second cavity.

[0021] Preferably, the data acquisition controller includes a multi-channel signal input interface, a synchronous clock module, a data storage module, and a communication module, and is capable of synchronously and continuously recording CO2 concentration time series data at at least two measurement points.

[0022] Preferably, the power supply unit is a rechargeable battery pack.

[0023] A method for determining the stability of soil organic carbon includes the following steps:

[0024] S1: Deploy the soil breathing chamber at the test site to form a closed or semi-closed gas collection space;

[0025] S2: Through natural diffusion, CO2 released by soil respiration accumulates in the gas collection space and reaches a dynamic equilibrium;

[0026] S3: Real-time detection of CO2 concentration within the gas collection space using a CO2 sensor;

[0027] S4: The CO2 concentration change data from multiple test points are synchronously collected and recorded through the data acquisition controller;

[0028] S5: Based on CO2 concentration change data, calculate soil respiration flux and then assess soil organic carbon stability.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] This invention, through the design of dedicated outdoor and indoor soil breathing chamber bases, enables the same core sensing and acquisition system to seamlessly adapt to natural soil surfaces and standard laboratory containers. This ensures that indoor controlled experiments and in-situ field observations can utilize the exact same measurement standards and equipment, improving the consistency and comparability of research data and simplifying experimental setup.

[0031] This invention abandons the traditional active pump sampling method, utilizing the principle of natural diffusion of gas molecules to balance the CO2 released from the soil within the breathing chamber. This avoids systematic errors caused by pressure disturbances from pump operation affecting the soil microenvironment and gas exchange process, thus improving the accuracy and reliability of measurements. Simultaneously, the system has extremely low overall power consumption, requiring only a small battery pack to support continuous, unattended monitoring for weeks or even months, making it particularly suitable for long-term observation in remote field areas, significantly reducing operation and maintenance costs and energy dependence.

[0032] The data acquisition controller of this invention incorporates a multi-channel interface and a synchronous clock, enabling it to drive and synchronously acquire CO2 sensor signals from multiple distributed locations. This allows researchers to simultaneously acquire soil respiration data from different treatments and locations, accurately capturing instantaneous response differences under the same environmental conditions. Combined with a high-precision 1-2 ppm CO2 sensor, this system can generate high-quality, high spatiotemporal resolution carbon flux time-series data, providing unprecedented technical means for in-depth analysis of the heterogeneity and patterns of soil organic carbon dynamics.

[0033] This invention adopts an integrated design of data acquisition, control, power supply, and display, which allows non-professionals to operate it after simple training, and is conducive to its promotion and application in various ecosystem monitoring networks, demonstration projects, and field stations.

[0034] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0035] Figure 1 This is a structural diagram of the multi-point synchronous diffusion soil organic carbon stability measurement system of the present invention.

[0036] Figure 2 This is a schematic diagram of the structure of the field soil breathing chamber in this invention.

[0037] Figure 3 This is a schematic diagram of the structure of the indoor soil breathing chamber in this invention.

[0038] Explanation of reference numerals in the attached drawings: 1. Soil breathing chamber; 1A. Indoor soil breathing chamber; 1-1. First base; 1-2. First cavity; 1B. Outdoor soil breathing chamber; 1-3. Second base; 1-4. Second cavity; 2. CO2 sensor; 3. Data acquisition controller; 4. Data display; 5. Cable transmission line. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. It should be noted that the drawings are schematic and not illustrated to scale. For clarity and convenience, the relative sizes and proportions of the parts shown in the drawings have been exaggerated or reduced in size. Any size is only illustrative and not limiting.

[0040] Example 1

[0041] This embodiment provides a multi-point synchronous diffusion soil organic carbon stability measurement system, such as... Figure 1 As shown, it includes a soil breathing chamber 1, a CO2 sensor 2, a data acquisition controller 3, a power supply unit, and a data display 4.

[0042] The soil breathing chamber is the core component of this system that comes into direct contact with the object being tested. Its function is to create a localized gas collection space where CO2 released from soil respiration can accumulate. This system is compatible with two designs to suit different scenarios.

[0043] Firstly, the outdoor soil breathing chamber 1B, such as Figure 2 As shown, it is specifically designed for complex terrain in the field. It includes a first base 1-1 and a first cavity 1-2 that can be sealed and fastened to it. The bottom edge of the first base 1-1 has a ring of conical spikes. During deployment, the conical spikes are manually pressed or stepped into the soil, thus forming a basic seal between the base 11 and the natural soil surface. The first cavity 1-2 is a transparent or semi-transparent cover with a sensor interface pre-installed at the top. This ensures that the measuring chamber can be quickly and stably established in the field without an external power supply or pumping device.

[0044] Secondly, the indoor soil breathing chamber 1A, such as Figure 3 As shown, it is specifically designed for standard laboratory culture containers. It includes a second base 1-3 and a second cavity 1-4. The second base 1-3 is a flat, ring-shaped structure with a sealing ring on its lower surface. In use, the second base 1-3 is placed stably on the opening of the culture container containing the soil sample, and the sealing ring provides a soft seal. The second cavity 1-4 is also fastened onto the base 1-3, forming a closed space. This design allows for quick integration with standardized laboratory equipment, facilitating culture experiments under controlled conditions.

[0045] CO2 sensor 2 is the sensing unit of this system. In this embodiment, a high-precision CO2 sensor based on the non-dispersive infrared principle is used, with a measurement accuracy of 1-2 ppm. Sensor 2 is fixedly installed at the top of the cavity inside the soil breathing chamber via a waterproof connector, with its probe directly exposed to the gas collection space for real-time monitoring of CO2 concentration changes. Sensor 2 is connected to the data acquisition controller 3 via a shielded cable transmission line 5.

[0046] The data acquisition controller 3 is responsible for coordinating and controlling the entire measurement process. Internally, it includes:

[0047] Multi-channel signal input interface: It can connect multiple CO2 sensors 2 at the same time, that is, it corresponds to multiple independent measurement points.

[0048] Synchronization clock module: Stamps all data channels with a unified and accurate timestamp, ensuring that data from multiple points is strictly synchronized in time.

[0049] Data storage module: Used to continuously store the CO2 concentration time series data collected from each channel.

[0050] Main control MCU and communication module: The main control MCU polls each sensor channel according to a preset sampling interval. The communication module can be a wired or wireless module, used to upload data to a remote server or receive commands.

[0051] In this embodiment, the power supply unit employs a high-capacity lithium-ion rechargeable battery pack. Due to its low-power design, this battery pack can provide continuous field power for systems including multiple sensors and controllers for weeks to months. The battery pack is equipped with a solar panel charging interface for recharging.

[0052] The data display 4 serves as the human-computer interaction interface, and in this embodiment, it is a portable touchscreen or tablet computer. It is connected to the data acquisition controller 3 via a data cable or wireless network, and can display the CO2 concentration at each location in real time in digital and graphical form. It also has data query, export, and simple chart analysis functions.

[0053] Working principle: In field plots, operators insert multiple field soil respiration chambers 1B into soil samples at different locations; in the laboratory, indoor soil respiration chambers 1A are placed on multiple culture containers. All CO2 sensors 2 are connected to the data acquisition controller 3 via cable transmission lines 5. After the controller 3 is powered on, it begins to synchronously collect CO2 concentration data at all points according to a set frequency. The accumulation of gas in the respiration chambers relies entirely on the natural diffusion of CO2 produced by soil respiration, without any forced airflow interference. Data is stored in real time and can be viewed on the data display 4. By analyzing the rate of change of CO2 concentration at each point over time, the soil respiration flux can be calculated as a key indicator for assessing soil organic carbon stability.

[0054] Example 2

[0055] This embodiment provides a method for measurement using the system described in Embodiment 1, and the specific steps are as follows:

[0056] S1: According to the experimental design, multiple test sites were selected in the target area. For field sites, after clearing surface debris, the base 11 of the field soil respiration chamber 1B was pressed into the soil; for indoor samples, the base 13 of the indoor soil respiration chamber 1A was sealed and placed on the culture container. Subsequently, the corresponding chambers were closed, and the CO2 sensors 2 in each respiration chamber were connected to the data acquisition controller 3 via cable transmission line 5.

[0057] S2: After the soil breathing chamber is closed, CO2 released by soil microorganisms and root respiration enters the chamber through natural diffusion. The system is allowed to stand for a short period of time to allow the initial gas to mix evenly. Then, the data acquisition controller 3 automatically begins to record the initial CO2 concentration at all points and initiates synchronous continuous monitoring.

[0058] S3: Within the preset measurement period, the data acquisition controller 3 uses its internal synchronous clock as a reference to periodically and synchronously acquire CO2 concentration readings from all connected channels and save them together with precise timestamps.

[0059] S4: After the measurement is completed, the data is displayed on the data display 4 or exported to a computer. The data is then processed using specialized software. The core task is to calculate the slope of CO2 concentration change over time at each location, and then, combined with the volume of the respiration chamber, soil area, and ambient temperature and pressure data, calculate the soil respiration flux at each location using the principles and formulas of static chamber or gas chromatography.

[0060] S5: By comparing soil respiration flux data from different treatments, locations, or time series, soils with lower organic carbon stability exhibit higher respiration fluxes under the same environmental conditions. Long-term synchronous monitoring allows for the analysis of dynamic patterns in carbon flux, thereby assessing the stability and turnover rate of the soil organic carbon pool, and serving research on ecosystem carbon cycling and assessment of carbon neutrality potential.

[0061] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0062] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multipoint simultaneous diffusion type soil organic carbon stability measurement system, characterized by, include: At least one soil breathing chamber is used to cover the soil to be tested or the culture container to form a gas collection space; At least one CO2 sensor is installed in the soil breathing chamber and communicates with the gas collection space to detect the CO2 concentration in the gas collection space; The data acquisition controller communicates with the CO2 sensor to synchronously acquire and process CO2 concentration data from multiple measurement points. The power supply unit provides power to the CO2 sensor and the data acquisition controller. A data display, which is communicatively connected to the data acquisition controller, is used to display and / or export the CO2 concentration data in real time; In this system, the gas in the gas collection space exchanges with the gas on the surface of the soil to be tested through natural diffusion, and the system measures the soil organic carbon stability by monitoring the change in CO2 concentration in the gas collection space.

2. The multi-point synchronous diffusion soil organic carbon stability measurement system according to claim 1, characterized in that: The soil breathing chamber includes a field soil breathing chamber for field measurements and / or an indoor soil breathing chamber for indoor measurements. The field soil breathing chamber includes a first base that can be inserted into or pressed into natural soil and a first cavity that can be sealed to the first base; The indoor soil breathing chamber includes a second base for sealing a standard culture container and a second cavity that is sealably connected to the second base.

3. The multi-point synchronous diffusion soil organic carbon stability measurement system according to claim 2, characterized in that: The first base has a conical spike on the side away from the first cavity for inserting into the soil.

4. The multi-point synchronous diffusion soil organic carbon stability determination system according to claim 2, characterized in that: The second base is provided with a sealing ring that matches the port of the second cavity.

5. The multi-point synchronous diffusion soil organic carbon stability measurement system according to claim 1, characterized in that, The data acquisition controller includes a multi-channel signal input interface, a synchronous clock module, a data storage module, and a communication module, and is capable of synchronously and continuously recording CO2 concentration time series data at at least two measurement points.

6. The multi-point synchronous diffusion soil organic carbon stability measurement system according to claim 1, characterized in that, The power supply unit is a rechargeable battery pack.

7. A method for determining the stability of soil organic carbon, using the system as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Deploy the soil breathing chamber at the test site to form a closed or semi-closed gas collection space; S2: Through natural diffusion, CO2 released by soil respiration accumulates in the gas collection space and reaches a dynamic equilibrium; S3: Real-time detection of CO2 concentration within the gas collection space using a CO2 sensor; S4: The CO2 concentration change data from multiple test points are synchronously collected and recorded through the data acquisition controller; S5: Based on CO2 concentration change data, calculate soil respiration flux and then assess soil organic carbon stability.

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