Soil carbon sequestration and emission reduction field determination method and device

Abstract

The invention relates to a soil carbon sequestration and emission reduction field determination method and device, and the method comprises the steps: carrying out organic carbon detection, microbial activity detection, volume weight detection and temperature and humidity detection on a sampling hole, and monitoring the concentration change of carbon dioxide and methane in the sampling hole to determine the emission flux of carbon dioxide and methane; then carrying out primary correction on the discharge flux by utilizing a microbial activity detection result; the method comprises the following steps: determining a soil carbon storage amount according to an organic carbon detection result, volume weight detection and temperature and humidity detection, performing secondary correction on the emission flux subjected to the primary correction by using the soil carbon storage amount, finally determining a carbon fixation amount based on the emission flux subjected to the secondary correction, and determining an emission reduction potential index in combination with the emission amount. The device not only can improve the detection efficiency and precision, but also is simple in structure and convenient to operate.

Description

Technical Field

[0001] The present invention relates to the field of soil detection technology, and more specifically to a field determination method and device for soil carbon sequestration and emission reduction. Background Art

[0002] As the global climate change problem becomes increasingly serious, soil carbon sequestration and emission reduction are of great significance for mitigating the greenhouse effect. Accurately measuring the carbon sequestration and emission reduction of field soils is crucial for evaluating the function of soil ecosystems and formulating agricultural strategies to cope with climate change.

[0003] However, existing soil carbon sequestration and emission reduction measurement devices have many shortcomings.

[0004] For example, some devices have complex structures and are difficult to operate, making them inconvenient for rapid field measurements; some devices have limited measurement accuracy and cannot accurately reflect the actual situation of soil carbon sequestration and emission reduction; and some devices cannot simultaneously take into account the measurement of multiple factors affecting soil carbon sequestration and emission reduction, resulting in incomplete measurement results.

[0005] Therefore, there is an urgent practical need to develop a field measurement device for soil carbon sequestration and emission reduction that is easy to operate, has high measurement accuracy, and can comprehensively measure multiple related factors. Summary of the invention

[0006] In view of this, in order to at least partially solve the above technical problems, the present invention provides a field determination method and device for soil carbon sequestration and emission reduction; in order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] On the one hand, the present application provides a field determination method for soil carbon sequestration and emission reduction, comprising:

[0008] Conduct organic carbon testing, microbial activity testing, bulk density testing, and temperature and humidity testing on the sampling holes;

[0009] Collect gas from the sampling holes and monitor changes in carbon dioxide and methane concentrations in the gas;

[0010] Determine the carbon dioxide and methane emission fluxes based on concentration changes, and use the microbial activity test results to make a correction to the emission fluxes;

[0011] The total soil carbon storage is determined based on the organic carbon test results, bulk density test, and temperature and humidity test, and the total soil carbon storage is used to make a secondary correction to the emission flux after the primary correction;

[0012] The carbon sequestration amount is determined based on the emission flux after secondary correction, and the emission reduction potential index is determined in combination with the emission amount.

[0013] Preferably, the emission flux is determined by the following formula:

[0014]

[0015] Where C represents the concentration of carbon dioxide or methane in the gas, dC / dt represents the concentration change rate, V represents the volume of the collection box, A represents the contact area between the collection box and the soil, M represents the molar mass of the gas, R represents a constant, and T represents the temperature.

[0016] Preferably, the emission flux is corrected using the microbial activity test results, including:

[0017]

[0018] In the formula, F raw represents the emission flux, ATP base Indicates reference microbial activity, ATP current It represents the current microbial activity detection value, and the exponent β represents the nonlinear effect of microbial activity on respiration, preferably 0.5.

[0019] Preferably, the total soil carbon storage is determined based on the organic carbon test results, bulk density test, and temperature and humidity test, including:

[0020]

[0021] In the formula, C stock Represents the total carbon storage, SOC i represents the soil organic carbon content in the i-th layer, ρ i represents the soil bulk density of the i-th layer, d i represents the depth of the i-th layer, θ i represents the volume moisture content of the i-th layer.

[0022] As a preference, the total soil carbon storage is used to perform a secondary correction on the emission flux corrected once; including:

[0023]

[0024] In the formula, F adj represents the primary corrected emission flux, a is the empirical attenuation coefficient, preferably 0.05-0.1, C inert Represents the bottom inert carbon stock, which can be directly obtained through organic carbon.

[0025] Preferably, the carbon sequestration amount is determined based on the emission flux after the secondary correction, including:

[0026]

[0027] In the formula, C loss represents the carbon loss, t 1 and t 2 Indicates the monitoring time interval. represents the secondary corrected emission flux of carbon dioxide, represents the secondary corrected emission flux of methane;

[0028] In this embodiment, CH 4 According to GWP-100, it is converted into carbon equivalent (1KgCH4 is about 25KgCO 2 -eq)

[0029] C net =C input -C loss

[0030] In the formula, C net Indicates the amount of carbon fixed, C input Represents carbon input.

[0031] Preferably, the emission reduction potential index is determined in combination with the emission amount, including:

[0032]

[0033] In the formula, C net Indicates the amount of carbon fixed, C net.max Indicates the regional or historical maximum net carbon sequestration, F baseline Denotes the base flux, F current represents the secondary corrected flux value; and

[0034]

[0035] Preferably, the reference flux F baseline Determined based on historical data or regional defaults, or derived as follows:

[0036]

[0037] Where k is the regional carbon loss coefficient, D is the depth of the sampling hole, C stock is the total carbon storage, and f(T,θ) represents the temperature and humidity control function.

[0038] In a second aspect, the present application provides a soil carbon sequestration and emission reduction field measurement device, which uses any of the soil carbon sequestration and emission reduction field methods described above, including a sampling probe and a gas collection box connected thereto, a gas analyzer and a detection host, wherein:

[0039] The sampling probe is used to sample the gas in the sampling hole and transport the sampled gas to the gas collection box; and to perform layered organic carbon detection, microbial activity detection, bulk density detection, and temperature and humidity detection on the sampling hole, and transmit the detection results to the detection host;

[0040] The gas collection box is used to collect gas;

[0041] The gas analyzer is connected to the gas collection box and is used to monitor the concentration changes of carbon dioxide and methane in the gas and transmit the monitoring results to the detection host;

[0042] The detection host is used to determine the carbon dioxide and methane emission fluxes according to the concentration changes, and make a primary correction to the emission flux using the microbial activity test results; determine the total soil carbon storage according to the organic carbon test results, bulk density test, and temperature and humidity test, and use the total soil carbon storage to make a secondary correction to the primary corrected emission flux; and determine the carbon fixation amount based on the emission flux after the secondary correction, and determine the emission reduction potential index in combination with the emission amount.

[0043] Preferably, the outer side of the sampling probe is a telescopic sleeve structure, and each level of the sleeve outer wall is circumferentially embedded with an organic carbon detection sensor, a soil microbial activity detection sensor, a soil bulk density detection sensor, and a soil temperature and humidity detection sensor; the probe of this application can complete the layered in-situ detection of soil at different depths at one time. Compared with traditional layer-by-layer drilling sampling, the operating efficiency is increased by more than 50%, and the damage to the soil structure caused by multiple sampling is avoided, and the data space consistency is stronger.

[0044] A polyurethane telescopic tube is arranged on the inside, which expands and contracts with the sleeve and samples are taken through the sampling gas port at the bottom of the sleeve, thereby effectively isolating external gas interference and ensuring the representativeness of the gas sample.

[0045] The present invention discloses a method and device for measuring soil carbon sequestration and emission reduction in the field, which has the following effects compared with the prior art:

[0046] 1. Considering a variety of factors that affect soil carbon sequestration and emission reduction, including organic carbon content, microbial activity, soil bulk density, temperature and humidity, etc., the measurement results are more comprehensive and objective; at the same time, stratified sampling is used to effectively improve the sampling efficiency;

[0047] 2. For the first time, microbial activity was introduced as a dynamic correction factor into flux calculation, breaking through the limitation of traditional models that only rely on environmental parameters; through secondary correction of the total soil carbon storage, the accurate calculation of carbon sequestration and emission reduction was further ensured;

[0048] 3. The carbon sequestration amount is determined based on the emission flux after secondary correction, and the emission reduction potential index is calculated in combination with the emission amount, which improves the measurement accuracy and provides a scientific basis for evaluating the emission reduction capacity of soil ecosystems and setting emission reduction targets;

[0049] 4. The retractable quadruped sampling probe integrates multiple types of sensors, combined with the dynamic sealing technology of the gas collection box and the intelligent early warning algorithm, to achieve multi-dimensional real-time monitoring of soil carbon sequestration and emission reduction. The device has high precision, scalability and automatic early warning functions, suitable for agricultural ecological research and carbon sink management, without the need for complex equipment assembly and debugging, and is convenient for researchers and farmers to use quickly and conveniently in actual field environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0051] Figure 1 A flow chart of the field determination method for soil carbon sequestration and emission reduction provided by the present invention;

[0052] Figure 2 A schematic diagram of the structure of the field measurement device for soil carbon sequestration and emission reduction provided by the present invention;

[0053] Figure 3 A cross-sectional view of the sampling probe structure provided by the present invention;

[0054] Figure 4 This is a front view of the sampling probe structure provided by the present invention. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Embodiment 1

[0057] The embodiment of the present invention discloses a method for determining soil carbon sequestration and emission reduction in the field, referring to Figure 1 , the steps include:

[0058] S1. Conduct stratified organic carbon testing, microbial activity testing, bulk density testing, and temperature and humidity testing on the sampling holes to assess the current scale and vertical distribution characteristics of the soil carbon pool, and take into account the determination of multiple factors affecting soil carbon sequestration and emission reduction;

[0059] S2, collect gas from the sampling hole and monitor the changes in the concentration of carbon dioxide and methane in the gas;

[0060] Due to CO 2 Molecules have strong absorption characteristics for infrared light in a specific infrared band (near 4.26μm). Therefore, the NDIR sensor can emit broad-spectrum infrared light through the gas sample, detect the attenuation of the transmitted light intensity, and use the Lambert-Beer Law to calculate CO 2 concentration.

[0061] For methane, tunable diode laser absorption technology is used for detection.

[0062] S3. Determine the carbon dioxide and methane emission fluxes according to the concentration changes, and make a correction to the emission fluxes using the microbial activity test results;

[0063] In one embodiment, after the gas collection box is sealed, the change of gas concentration in the box over time is continuously monitored (e.g., recorded every 10 seconds); then the concentration-time curve is fitted, usually a linear or nonlinear growth (e.g., CO 2 Emission flux); finally, the emission flux is determined by the following formula:

[0064]

[0065] Where C represents the concentration of carbon dioxide or methane in the gas, dC / dt represents the concentration change rate, V represents the volume of the collection box, A represents the contact area between the collection box and the soil, M represents the molar mass of the gas, R represents a constant, and T represents the temperature.

[0066] Then, the emission flux is corrected once using the microbial activity test results, including:

[0067]

[0068] In the formula, F raw represents the emission flux, ATP base Indicates reference microbial activity, ATP current It represents the current microbial activity detection value, and the exponent β represents the nonlinear effect of microbial activity on respiration, preferably 0.5.

[0069] This application is the first to introduce microbial activity as a dynamic correction factor into flux calculation, breaking through the limitation of traditional models that only rely on environmental parameters.

[0070] S4. Determine the total soil carbon storage based on the organic carbon detection results, bulk density detection, and temperature and humidity detection, and perform a secondary correction on the initially corrected emission flux using the total soil carbon storage; the secondary correction integrates the spatial distribution of carbon storage, physical structure, and moisture status, combines short-term microbial respiration signals with long-term carbon stability, realizes the leap from "instantaneous flux monitoring" to "net carbon sequestration potential assessment", and provides core quantitative decision-making parameters for climate-smart agriculture. Specifically,

[0071] In this embodiment, determining the total soil carbon storage based on the organic carbon detection results, bulk density detection, and temperature and humidity detection includes:

[0072]

[0073] where C stock represents the total carbon storage, SOC i represents the organic carbon content of the i-th soil layer, ρ i represents the bulk density of the i-th soil layer, d i represents the depth of the i-th layer, θ i represents the volumetric water content of the i-th layer.

[0074] Perform a secondary correction on the initially corrected emission flux using the total soil carbon storage; including:

[0075]

[0076] where F adj represents the initially corrected emission flux, a is an empirical decay coefficient, preferably taken as 0.05 - 0.1, C inert represents the bottom-layer inert carbon storage, which can be directly obtained from organic carbon.

[0077] S5. Determine the carbon sequestration amount based on the emission flux after the secondary correction, and determine the emission reduction potential index in combination with the emissions.

[0078] Determining the carbon sequestration amount based on the emission flux after the secondary correction respectively includes:

[0079]

[0080] where C loss represents the carbon loss amount, t 1 and t 2 represent the monitoring time interval, represents the secondary corrected emission flux of carbon dioxide, represents the secondary corrected emission flux of methane;

[0081] In this embodiment, CH 4 is converted to carbon equivalent according to GWP-100 (1 Kg CH4 is approximately 25 Kg CO 2 -eq)

[0082] C net =C input -C loss

[0083] In the formula, C net Indicates carbon sequestration, reflecting the net change of soil carbon pool, C input It represents the amount of carbon input. It can be measured directly: through field experiments to determine the amount of litter, root biomass, etc., and estimate based on the carbon content (usually 40-50%); or estimated through models: if there is a lack of measured data, it can be estimated using empirical models based on crop yield and management measures (such as the proportion of straw returned to the field).

[0084] The calculation formula of emission reduction potential index is:

[0085]

[0086] In the formula, C net Indicates the amount of carbon fixed, C net.max It represents the regional or historical maximum net carbon sequestration, which can be determined through model simulation or long-term observation. current represents the secondary corrected flux value; and

[0087]

[0088] F baseline It indicates that the benchmark flux is determined based on historical data or regional default values. When historical flux data is lacking, it can be derived as follows:

[0089]

[0090] Where k is the regional carbon loss coefficient, D is the depth of the sampling hole, C stock is the total carbon storage, and f(T,θ) represents the temperature and humidity control function.

[0091] This application adopts a two-stage dynamic correction for the emission flux, including:

[0092] Nonlinear correction of microbial activity: The microbial activity index (α=0.5) was introduced for the first time to perform nonlinear correction on the emission flux. Based on the logistic growth characteristics of microbial respiration, the flux calculation error was reduced from ±15% of the traditional linear model to ±5%.

[0093] Carbon reserve decay compensation mechanism: By comparing the total carbon reserve with the inert carbon baseline value, the flux value is dynamically adjusted using the empirical decay coefficient (β=0.05-0.1), effectively distinguishing the contribution of the active carbon pool from the stable carbon pool, and improving the accuracy of long-term carbon fixation prediction by 20%.

[0094] Embodiment 2

[0095] The present application provides a field measurement device for soil carbon sequestration and emission reduction, as Figure 2 shown, which includes a sampling probe connected thereto, a gas collection box, a gas analyzer, and a detection host. Among them,

[0096] The sampling probe is used to sample the gas in the sampling hole, and transport the sampled gas to the gas collection box; and perform layered organic carbon detection, microbial activity detection, bulk density detection, and temperature and humidity detection on the sampling hole, and transmit the detection results to the detection host;

[0097] The gas collection box is used to collect gas; in this embodiment, the gas collection box 2 is in an inverted funnel shape, as Figure 3 and Figure 4 shown, and an annular airbag 3 is provided at the bottom, which can contact the ground to form a sealed space after inflation to improve the purity of the collected gas;

[0098] The gas analyzer is connected to the gas collection box through a valve 1, and is used to monitor the changes in the concentrations of carbon dioxide and methane in the gas, and transmit the monitoring results to the detection host;

[0099] The detection host is used to determine the carbon dioxide and methane emission fluxes according to the concentration changes, and perform a primary correction on the emission fluxes by using the microbial activity detection results; determine the total soil carbon storage according to the organic carbon detection results, bulk density detection, and temperature and humidity detection, and perform a secondary correction on the once-corrected emission fluxes by using the total soil carbon storage; and determine the carbon sequestration amount based on the twice-corrected emission fluxes, and combine the emissions to determine the emission reduction potential index.

[0100] As a preferred implementation, an intelligent early warning unit is provided in the detection host, which is used to support the abnormal identification and hierarchical early warning of soil carbon sequestration and emission reduction based on a threshold algorithm dynamically corrected by historical data, such as sound and light alarms and mobile terminal push.

[0101] In one embodiment, the grading rules are as follows:

[0102] ERI > 30%: High emission reduction potential (green), it is recommended to maintain management;

[0103] 10% < ERI < 30%: Medium potential (yellow), it is recommended to optimize fertilization;

[0104] ERI < 10%: Low potential (red), systematic improvement is required.

[0105] During operation, first, according to the required sampling depth, the probe is positioned by the detection host, and the gas collection box contacts the ground. At this time, the airbag is inflated to complete the seal; then the sample is pumped to the collection box by a gas pump; when the required gas pressure is reached, the valve 1 is opened and then analyzed by the gas analyzer, and then uploaded to the detection host.

[0106] To further optimize the above technical solution, Figure 3 The outside of the sampling probe is a telescopic sleeve structure 4, which can adopt a segmented thread locking structure and can independently adjust the insertion depth (10-100cm). In a preferred embodiment, a spiral soil-breaking cone head 7 is provided at the end;

[0107] The outer wall surface of each sleeve of the rod body is covered with an anti-corrosion coating, and organic carbon detection sensors, soil microbial activity detection sensors, soil bulk density detection sensors and soil temperature and humidity detection sensors are embedded circumferentially; a polyurethane telescopic tube 5 is arranged on the inside, and the telescopic tube is telescoped with the sleeve, and sampling is carried out through the sampling air port 6 at the bottom of the sleeve.

[0108] Preferably, in order to solve the stability problem of the traditional single-rod structure, the probe is designed as a four-legged probe in the present application.

[0109] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0110] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A field determination method for soil carbon sequestration and emission reduction, characterized in that: include: Conduct organic carbon testing, microbial activity testing, bulk density testing, and temperature and humidity testing on the sampling holes; Collect gas from the sampling holes and monitor changes in carbon dioxide and methane concentrations in the gas; Determine the carbon dioxide and methane emission fluxes based on concentration changes, and use the microbial activity test results to make a correction to the emission fluxes; The total soil carbon storage is determined based on the organic carbon test results, bulk density test, and temperature and humidity test, and the total soil carbon storage is used to make a secondary correction to the emission flux after the primary correction; The carbon sequestration amount is determined based on the emission flux after secondary correction, and the emission reduction potential index is determined in combination with the emission amount.

2. The field determination method for soil carbon sequestration and emission reduction according to claim 1, characterized in that: The emission flux is determined by the following formula: Where C represents the concentration of carbon dioxide or methane in the gas, dC / dt represents the concentration change rate, V represents the volume of the collection box, A represents the contact area between the collection box and the soil, M represents the molar mass of the gas, R represents a constant, and T represents the temperature.

3. The field determination method for soil carbon sequestration and emission reduction according to claim 1, characterized in that: The emission flux is corrected using the results of microbial activity testing, including: In the formula, F raw represents the emission flux, ATP base Indicates reference microbial activity, ATP current It represents the current microbial activity detection value, and the exponent β represents the nonlinear effect of microbial activity on respiration, preferably 0.

5.

4. The field determination method for soil carbon sequestration and emission reduction according to claim 1, characterized in that: The total soil carbon storage is determined based on the organic carbon test results, bulk density test, and temperature and humidity test, including: In the formula, C stock Represents the total carbon storage, SOC i represents the soil organic carbon content in the i-th layer, ρ i represents the soil bulk density of the i-th layer, d i represents the depth of the i-th layer, θ i represents the volume moisture content of the i-th layer.

5. The field determination method for soil carbon sequestration and emission reduction according to claim 4, characterized in that: The total soil carbon storage is used to make a secondary correction to the emission flux after the primary correction; including: In the formula, F adj represents the primary corrected emission flux, a is the empirical attenuation coefficient, preferably 0.05-0.1, and Cinert represents the bottom inert carbon storage.

6. The field determination method for soil carbon sequestration and emission reduction according to claim 1, characterized in that: The carbon sequestration amount is determined based on the secondary corrected emission flux, including: In the formula, C loss represents the carbon loss, t1 and t2 represent the monitoring time interval, F co2,final represents the secondary corrected emission flux of carbon dioxide, F cH4,final represents the secondary corrected emission flux of methane; Cnet=Cinput-Closs In the formula, C net Indicates the amount of carbon fixed, C input Represents carbon input.

7. The field determination method for soil carbon sequestration and emission reduction according to claim 1, characterized in that: Combined with the emissions, the emission reduction potential index is determined, including: In the formula, C net Indicates the amount of carbon fixed, C net.max Indicates the regional or historical maximum net carbon sequestration, F baseline Denotes the base flux, F current represents the secondary corrected flux value; and 8. The field determination method for soil carbon sequestration and emission reduction according to claim 7, characterized in that: Base Flux F baseline Determined based on historical data or regional defaults, or derived as follows: Where k is the regional carbon loss coefficient, D is the depth of the sampling hole, C stock is the total carbon storage, and f(T,θ) represents the temperature and humidity control function.

9. A soil carbon sequestration and emission reduction field measurement device, characterized in that: The field method for soil carbon sequestration and emission reduction according to any one of claims 1 to 8 comprises a sampling probe and a gas collection box connected thereto, a gas analyzer and a detection host, wherein: The sampling probe is used to sample the gas in the sampling hole and transport the sampled gas to the gas collection box; and to perform layered organic carbon detection, microbial activity detection, bulk density detection, and temperature and humidity detection on the sampling hole, and transmit the detection results to the detection host; The gas collection box is used to collect gas; The gas analyzer is connected to the gas collection box and is used to monitor the concentration changes of carbon dioxide and methane in the gas and transmit the monitoring results to the detection host; The detection host is used to determine the carbon dioxide and methane emission fluxes according to the concentration changes, and make a primary correction to the emission flux using the microbial activity test results; determine the total soil carbon storage according to the organic carbon test results, bulk density test, and temperature and humidity test, and use the total soil carbon storage to make a secondary correction to the primary corrected emission flux; and determine the carbon fixation amount based on the emission flux after the secondary correction, and determine the emission reduction potential index in combination with the emission amount.

10. The soil carbon sequestration and emission reduction field measurement device according to claim 9, characterized in that: The outside of the sampling probe is a telescopic sleeve structure, and the outer wall of each level of the sleeve is embedded with organic carbon detection sensors, soil microbial activity detection sensors, soil bulk density detection sensors, and soil temperature and humidity detection sensors. A polyurethane telescopic tube is arranged on the inside, which telescopes and retracts with the sleeve and takes samples through the sampling air port at the bottom of the sleeve.

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