An in-situ assessment method of carbon sequestration of an ecosystem based on a multi-compartment mineral bag array

Abstract

The present application relates to the technical field of ecosystem carbon sink monitoring, and discloses an in-situ evaluation method for carbon fixation of an ecosystem based on a multi-compartment mineral bag array, which comprises the following steps: preparing a multi-compartment box device, a plurality of compartments are arranged in the box body along the soil depth direction, and the box body and the partition structure are provided with hollow holes for the entry of plant roots, soil solution and microorganisms; standard mineral materials that have been treated to remove carbon and have a baseline value of organic carbon before being buried are packaged into mineral bags and placed in different compartments to form a mineral bag array; a plurality of box devices are buried in the same treatment sample at one time, and the corresponding devices are taken out according to different sampling years; after the mineral bags are recovered, the organic carbon content is measured, the baseline value before being buried is deducted, and the increment of mineral combined organic carbon is obtained; and finally, the formation capacity of the stable carbon pool and the saturation state of the mineral carbon are evaluated according to the multi-year cumulative data and the annual increment sequence.

Description

Technical Field

[0001] This invention relates to the field of ecosystem carbon sink monitoring technology, specifically to an in-situ assessment method for ecosystem carbon sequestration based on a multi-compartment mineral bag array. Background Technology

[0002] Soil organic carbon is an important carbon pool in terrestrial ecosystems. Among them, mineral-bound organic carbon is a relatively stable carbon component, and its formation process is influenced by plant root input, microbial transformation, and the binding capacity of mineral surfaces. In-situ assessment of the stable carbon pool formation capacity of ecosystems is an important basis for judging the carbon sink potential of ecosystems such as grasslands, forests, and farmlands.

[0003] Current methods for assessing soil carbon sequestration typically include soil drilling, profile sampling, total organic carbon (TOC) measurement, or long-term locational observation. While these methods can reflect changes in the soil carbon pool over a certain period, natural soils contain high levels of background organic carbon, and there is significant spatial heterogeneity between different soil layers and sampling locations. Short-term carbon additions are easily diluted by background carbon, and it is difficult to maintain complete consistency between sampling locations across different years.

[0004] Therefore, existing methods struggle to maintain consistency in mineral material type, burial depth, and annual sampling objects under in-situ conditions when assessing the formation process of stable carbon pools. This makes it difficult to obtain the incremental amount of mineral-bound organic carbon, interannual accumulation rate, and mineral carbon saturation trend continuously, sensitively, and comparatively. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an in-situ assessment method for ecosystem carbon sequestration based on multi-compartment mineral bag arrays, thereby resolving the technical problems existing in the prior art.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: An in-situ assessment method for ecosystem carbon sequestration based on multi-compartment mineral bag arrays includes the following steps: S1: Prepare a multi-compartment box device. The multi-compartment box device includes a box body, a partition structure set inside the box body, and an openable transparent cover set on the box body. The partition structure divides the internal space of the box body into multiple compartments along the soil depth direction. The side walls of the box body and the partition structure are provided with perforated holes for plant roots, soil solution and microorganisms to enter. S2: Prepare standardized mineral bags by encapsulating standardized mineral materials with an initial organic carbon content of zero in a water-permeable and solute-permeable mesh bag to form a mineral bag for adsorbing and stabilizing newly introduced organic carbon. S3: Construct a mineral bag array, place multiple mineral bags in different compartments of the multi-compartment box device, and record the burial depth and mineral material type of each mineral bag. S4: Multiple multi-compartment box devices containing mineral bag arrays are buried at one time in the same treatment plot, and the multiple multi-compartment box devices are respectively assigned to different sampling years; S5: Bury the multi-compartment box device in situ in the soil of the ecosystem to be evaluated, so that the main body of the box is in contact with the surrounding soil and the plant roots can enter the main body of the box through the perforated holes and come into contact with the mineral bag. S6: According to the preset annual sampling plan, the corresponding multi-compartment box device is taken out in each sampling year, and the mineral bags in each compartment are recycled by opening the openable transparent cover. S7: Pre-treat the mineral materials in the recovered mineral bags and determine the organic carbon content in the mineral materials. Use the measured organic carbon content as the increment of newly formed mineral-bound organic carbon under this burial time. S8: Based on the increase in mineral-bound organic carbon corresponding to different sampling years, obtain the cumulative data of mineral-bound organic carbon changes with burial time, and calculate the accumulation rate of mineral-bound organic carbon. S9: Based on the accumulated data and accumulation rate, determine whether the accumulation of mineral-bound organic carbon tends to level off, and assess the stable carbon pool formation capacity and mineral carbon saturation status of the ecosystem to be assessed.

[0007] Preferably, the main body of the box is an acrylic box, the main body of the box is arranged along the soil depth direction, and the partition structure divides the internal space of the main body of the box into three compartments, which correspond to the surface soil, the middle soil and the deep soil respectively.

[0008] Preferably, the burial depth of the main body of the box is 30cm, and the three compartments correspond to the soil layers of 0 to 10cm, 10 to 20cm and 20 to 30cm respectively along the soil depth direction; The diameter of the perforated holes on the side wall of the main body of the box is 5 to 8 mm, and the spacing between the holes is 5 mm. The diameter of the perforated holes on the partition structure is 5 to 8 mm.

[0009] Preferably, the openable transparent cover is an integral transparent cover that covers all compartments. The integral transparent cover is connected to the main body of the box by a buckle or screw, and a sealing gasket is provided at the connection. In step S6, after opening the integral transparent cover, all compartments are exposed simultaneously to uniformly collect the mineral bags in different compartments and observe the root distribution in each compartment.

[0010] Preferably, in step S2, the standardized mineral material is selected from one of low-reactivity mineral materials, medium-reactivity mineral materials, and high-reactivity mineral materials; The low-reactive mineral material is a mixture of kaolin and acid-washed quartz sand in a mass ratio of 50:50; The medium reactive mineral material is a mixture of montmorillonite and acid-washed quartz sand in a mass ratio of 50:50; The highly reactive mineral material is hydrated iron oxide-coated quartz sand, or a composite material formed by goethite and montmorillonite.

[0011] Preferably, in step S2, each mineral bag contains 15.0g of standardized mineral material. The mesh bag is a nylon mesh bag with a pore size of 53μm. The mineral bag is 9cm long and 4cm wide. After being sterilized by high-pressure steam at 121℃ for 30min, the mineral bags are used for in-situ burial.

[0012] Preferably, in step S3, the mineral bag array is arranged in any of the following ways: The first arrangement involves placing mineral bags with different reactivity in different compartments of the same multi-compartment box device to simultaneously compare the effects of mineral material type and burial depth on the formation of mineral-bound organic carbon. The second arrangement involves placing the same reactive mineral bags in different compartments of the same multi-compartment box device to compare the differences in the accumulation of mineral-bound organic carbon of the same mineral material at different soil depths.

[0013] Preferably, in step S4, five multi-compartment box devices are buried at one time in the same treatment plot. The five multi-compartment box devices are marked as Y1, Y2, Y3, Y4 and Y5, respectively, and correspond to the destructive sampling in the 1st, 2nd, 3rd, 4th and 5th years, respectively; the distance between two adjacent multi-compartment box devices is not less than 50cm. In step S6, the multi-compartment box device corresponding to Y1 is taken out in the first year, the multi-compartment box device corresponding to Y2 is taken out in the second year, the multi-compartment box device corresponding to Y3 is taken out in the third year, the multi-compartment box device corresponding to Y4 is taken out in the fourth year, and the multi-compartment box device corresponding to Y5 is taken out in the fifth year. Each multi-compartment box device is subjected to destructive sampling only once, so that the mineral bag samples obtained in different years are all independent buried samples.

[0014] Preferably, in step S8, the accumulation rate of mineral-bound organic carbon includes the interannual accumulation rate and the average accumulation rate; The interannual accumulation rate is obtained by subtracting the mineral-bound organic carbon content of the previous sampling year from the mineral-bound organic carbon content of the subsequent sampling year. The average accumulation rate is obtained by dividing the mineral-bound organic carbon content in the nth sampling year by the number of burial years n; In step S9, when the mineral-bound organic carbon continuously increases with the increase of burial time and the annual increment decreases year by year, it is determined that there is a mineral carbon saturation trend. When the mineral-bound organic carbon increases linearly with burial time, it is determined that the mineral carbon saturation state has not yet been reached. The maximum carbon adsorption capacity of the corresponding mineral material was determined by fitting the accumulated data using an adsorption model.

[0015] Preferably, after step S9, there is also a disturbance impact assessment step: comparing the mineral-bound organic carbon increment, mineral-bound organic carbon accumulation rate and mineral carbon saturation state obtained under different treatment plots to assess the impact of one of the treatment factors, namely climate warming, nitrogen addition, drought treatment, grazing treatment, enclosure restoration and reseeding restoration, on the stable carbon pool formation capacity of the ecosystem to be assessed. In the disturbance impact assessment step, the increase in mineral-bound organic carbon is used as the direct response variable, and a multi-factor variance analysis is conducted in combination with the treatment type, mineral material type and burial depth to obtain the differences in the impact of different treatment factors, different mineral material types and different soil depths on the ability to form a stable carbon pool.

[0016] In summary, the present invention has the following main beneficial effects: This application utilizes a multi-compartment chamber device buried in situ in the soil, with standardized mineral bags, treated for carbon removal and possessing baseline organic carbon values ​​before burial, placed in each compartment. This allows plant roots, soil solution, and microorganisms to enter the chamber through perforations and come into contact with the mineral bags, achieving the effect of obtaining the increase in mineral-bound organic carbon under conditions close to the natural rhizosphere environment. Compared to directly collecting natural soil to determine total organic carbon, this application does not use natural soil with high background carbon content and strong spatial heterogeneity as the sole detection object. Instead, it uses standardized mineral materials with clearly defined mineral types and baseline values ​​as carbon-binding carriers. The increase in newly formed mineral-bound organic carbon is determined by the difference between the recovered organic carbon content and the baseline value before burial. This reduces the impact of the soil background organic carbon dilution effect on the identification of short-term carbon sequestration changes and improves the sensitivity and comparability of assessing the stable carbon pool formation capacity under different treatment conditions.

[0017] By dividing the main body of the container into multiple compartments along the soil depth direction and placing mineral bags in different compartments, while simultaneously recording the burial depth and mineral type of each mineral bag, the system effectively distinguishes the contribution of different soil depths and mineral reactivity to the formation of mineral-bound organic carbon within the same in-situ burial system. The multi-compartment structure allows the mineral bags to maintain a relatively stable depth during burial, reducing the problem of inconsistent sampling locations encountered in traditional scattered bag burial or soil drilling sampling. The integrated transparent cover allows all compartments to be exposed simultaneously during annual sampling, facilitating the unified retrieval of mineral bags and observation of root distribution. This reduces human error caused by confusion in the order of operation, exposure time, or numbering of samples from different compartments, establishing a correspondence between depth stratification data, mineral type data, and root observation results.

[0018] By embedding multiple parallel chambers within the same treatment plot and assigning each chamber to a different sampling year, destructive sampling is performed on the corresponding chamber each year. This method achieves the goal of obtaining independent sample sequences over multiple years while minimizing the impact of repeated disturbances. It avoids root damage, soil structure disturbance, changes in microbial communities, and mineral bag displacement caused by repeated opening, backfilling, and reburying of the same chamber, thus ensuring good continuity and comparability of mineral-bound organic carbon data obtained from different years. Furthermore, by using cumulative data and interannual increment sequences to determine whether mineral-bound organic carbon accumulation is slowing down, in-situ assessments can be provided for the formation rate of stable carbon pools in ecosystems, mineral carbon saturation trends, and the impact of different disturbances or restoration measures on carbon sink functions. Attached Figure Description

[0019] Figure 1 This is a flowchart of the method of the present invention.

[0020] Figure 2 This is the reactive mineral diagram of the present invention.

[0021] Figure 3 This is a schematic diagram of the simultaneous installation of the five parallel devices of the present invention.

[0022] Figure 4 This is a schematic diagram of the multi-compartment box device of the present invention. Detailed Implementation

[0023] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 refer to Figure 1-4 An in-situ assessment method for ecosystem carbon sequestration based on multi-compartment mineral bag arrays includes the following steps: S1: Prepare a multi-compartment box device. The multi-compartment box device includes a box body, a partition structure set inside the box body, and an openable transparent cover set on the box body. The partition structure divides the internal space of the box body into multiple compartments along the soil depth direction. The side walls of the box body and the partition structure are provided with perforated holes for plant roots, soil solution and microorganisms to enter. S2: Prepare standardized mineral bags by encapsulating standardized mineral materials with an initial organic carbon content of zero in a water-permeable and solute-permeable mesh bag to form a mineral bag for adsorbing and stabilizing newly introduced organic carbon. S3: Construct a mineral bag array, place multiple mineral bags in different compartments of the multi-compartment box device, and record the burial depth and mineral material type of each mineral bag. S4: Multiple multi-compartment box devices containing mineral bag arrays are buried at one time in the same treatment plot, and the multiple multi-compartment box devices are respectively assigned to different sampling years; S5: Bury the multi-compartment box device in situ in the soil of the ecosystem to be evaluated, so that the main body of the box is in contact with the surrounding soil and the plant roots can enter the main body of the box through the perforated holes and come into contact with the mineral bag. S6: According to the preset annual sampling plan, the corresponding multi-compartment box device is taken out in each sampling year, and the mineral bags in each compartment are recycled by opening the openable transparent cover. S7: Pre-treat the mineral materials in the recovered mineral bags and determine the organic carbon content in the mineral materials. Use the measured organic carbon content as the increment of newly formed mineral-bound organic carbon under this burial time. S8: Based on the increase in mineral-bound organic carbon corresponding to different sampling years, obtain the cumulative data of mineral-bound organic carbon changes with burial time, and calculate the accumulation rate of mineral-bound organic carbon. S9: Based on the accumulated data and accumulation rate, determine whether the accumulation of mineral-bound organic carbon tends to level off, and assess the stable carbon pool formation capacity and mineral carbon saturation status of the ecosystem to be assessed.

[0025] Preparation of multi-compartment box device: A multi-compartment box device is prepared, the multi-compartment box device including a box body, a partition structure, an openable transparent cover, a portable handle and a closed bottom plate.

[0026] The main body of the box is made of acrylic material. Acrylic material has a certain structural strength and transparency, which facilitates the inspection of the internal condition of the box before field installation and also facilitates the observation of root distribution and mineral bag location within the compartment during harvest. The main body of the box is set along the soil depth direction, corresponding to the vertical direction of the device after it is buried in the soil. In one specific implementation, the main body of the box is 30cm deep, 12cm long, and 4cm wide.

[0027] The side walls of the main body of the container are perforated. The purpose of these perforations is to allow plant roots, soil solution, and microorganisms from the surrounding soil to enter the interior of the container after the device is buried, thus placing the mineral bag in in-situ conditions close to the natural rhizosphere environment. In one specific implementation, the diameter of the perforations is 5 to 8 mm, and the spacing between the perforations is 5 mm. This diameter provides a channel for root entry and soil solution exchange without significantly reducing the overall structural strength of the container. The perforations can be located on the four sides of the container or on multiple side walls in contact with the surrounding soil, depending on the burial direction of the device.

[0028] The main body of the container is equipped with a partition structure. This partition structure divides the internal space of the container into multiple compartments along the soil depth direction. In one specific implementation, the partition structure divides the main body into three compartments, corresponding sequentially to soil layers of 0-10cm, 10-20cm, and 20-30cm. Each compartment is 10cm deep, 4cm long, and 4cm wide. The partition structure also features perforations with a diameter of 5-8mm. These perforations allow for limited communication between the root system and the soil solution in adjacent compartments, preventing complete isolation between compartments and deviation from the actual soil environment. Simultaneously, the compartment boundaries maintain the positional stability of the mineral bags at different depths.

[0029] The main body of the container is equipped with an openable transparent cover. Preferably, the openable transparent cover is an integral transparent cover that covers all compartments. The integral transparent cover is connected to the main body of the container via clips or screws, with a sealing gasket at the connection point. The sealing gasket is used to reduce the entry of unwanted soil particles at the edge of the cover, preventing samples from different compartments from mixing at the cover edge. The integral transparent cover design allows all compartments to be exposed simultaneously by opening only one cover during annual sampling, thus enabling the unified retrieval of mineral bags from different compartments and simultaneous observation of root distribution in compartments at different depths. Compared to using separate covers for each compartment, the integral transparent cover reduces the risk of exposure time differences and sample contamination caused by opening each cover individually, and also ensures consistent operating conditions for each compartment during harvest.

[0030] A portable handle is installed on the top of the main body of the container. The portable handle is used to lift the main body of the container as a whole during burial and harvesting. A closed bottom plate is installed at the bottom of the main body of the container. The closed bottom plate is used to support the mineral bags in each compartment and prevent the mineral bags from sliding out from the bottom of the main body of the container when the device is buried in the soil or when the soil is removed.

[0031] In this embodiment, the multi-compartment box device does not function as a closed culture container, but rather as a supporting structure in the in-situ soil with a fixed depth, fixed compartment boundaries, and a uniform recyclable interface. It maintains material exchange with the natural soil environment through perforations, defines the depth of the mineral bags through the partition structure, and ensures consistency in the harvesting process through an integral transparent cover, thereby providing a spatial positioning basis for subsequent determination of the increase in mineral-bound organic carbon.

[0032] Preparation of standardized mineral bags: Prepare standardized mineral bags. Standardized mineral bags consist of mesh bags and standardized mineral materials encapsulated within the mesh bags.

[0033] Standardized mineral materials undergo carbon removal treatment before bagging, and the baseline organic carbon value before burial is determined. This carbon removal treatment aims to reduce the influence of pre-existing measurable organic carbon in the standardized mineral materials on subsequent measurement results. The baseline organic carbon value before burial refers to the organic carbon content measured by the same testing procedure before in-situ burial of the standardized mineral materials. By setting a baseline organic carbon value before burial, the residual background organic carbon in the standardized mineral materials can be avoided from being mistaken for newly formed mineral-bound organic carbon. In actual measurement, even if the organic carbon content before burial is lower than the instrument's detection limit, the detection record is used as the baseline, rather than absolute zero as the sole criterion.

[0034] Standardized mineral materials can be selected from low-reactivity, medium-reactivity, and high-reactivity mineral materials. Low-reactivity mineral materials can be a mixture of kaolin and acid-washed quartz sand in a 50:50 mass ratio. Medium-reactivity mineral materials can be a mixture of montmorillonite and acid-washed quartz sand in a 50:50 mass ratio. High-reactivity mineral materials can be hydrated iron oxide-coated quartz sand or a composite material of goethite and montmorillonite. Low-reactivity, medium-reactivity, and high-reactivity mineral materials have different surface reactivity and organic carbon binding capabilities, used to compare the differences in the contribution of different mineral materials to the formation of stable carbon.

[0035] The mesh bag is a nylon mesh bag with a preset pore size. This preset pore size allows rhizosphere solution, dissolved organic matter, and microorganisms to enter the mesh bag, while limiting the leakage of standardized mineral materials. In one specific embodiment, the mesh bag pore size is 53 μm. To ensure an effective fit between the mesh bag pore size and the standardized mineral materials, the standardized mineral materials can be pre-wetted, mixed, and checked for leakage before bagging. For mineral materials containing fine-grained components, their retention stability in the mesh bag can be improved by mixing, coating, or combining them with acid-washed quartz sand. After the above treatment, the mesh bag allows dissolved organic matter to enter while reducing the risk of standardized mineral materials being lost with water flow or during rinsing.

[0036] Each mineral bag contains 15.0g of standardized mineral material. The mineral bag is 9cm long and 4cm wide. This size matches the compartment dimensions, ensuring the mineral bag remains relatively stable after placement and is less prone to significant movement during backfilling or root growth. After filling, the mineral bags are heat-sealed, ensuring a continuous and complete seal to prevent leakage of the standardized mineral material. The sealed mineral bags are then autoclaved at 121℃ for 30 minutes before use. This sterilization process reduces the impact of pre-packaging microbial variations on the initial state of different mineral bags, ensuring more consistent initial conditions before they are introduced into the soil.

[0037] In this embodiment, the standardized mineral bag serves to provide a carbon-binding carrier with clearly defined mineral types, baseline organic carbon values ​​before burial, and boundaries of material entry. This differs from direct sampling of natural soil, which contains a large amount of background organic carbon and exhibits spatial heterogeneity. The standardized mineral bag can transform the binding process of newly introduced carbon onto standard mineral materials into comparable incremental data.

[0038] Construction of mineral bag arrays: Multiple mineral bags were placed in different compartments of the multi-compartment enclosure to construct a mineral bag array. One mineral bag was placed in each compartment, and the burial depth and mineral type of each mineral bag were recorded.

[0039] The mineral bag array can be arranged in two ways. The first arrangement involves placing mineral bags of varying reactivity in different compartments of the same multi-compartment enclosure. For example, low-reactivity, medium-reactivity, and high-reactivity mineral bags can be placed in compartments 0-10 cm, 10-20 cm, and 20-30 cm, respectively. This arrangement allows for simultaneous comparison of the effects of mineral material type and burial depth on the formation of mineral-bound organic carbon within the same device.

[0040] The second arrangement involves placing bags of the same reactivity in different compartments of the same multi-compartment enclosure. For example, all three compartments could contain bags of highly reactive minerals. This arrangement eliminates the influence of differences in mineral material types and allows for a focused comparison of the accumulation of mineral-bound organic carbon at different soil depths using the same mineral material.

[0041] In practice, the installation record sheet should record the number of each multi-compartment box device, the corresponding treatment plot, the corresponding sampling year, the depth of each compartment, the mineral bag number, the mineral material type, the burial date, and the burial location. These records ensure that subsequently recovered mineral bags accurately correspond to their original depth and mineral type, preventing sample number confusion that could lead to data untraceability.

[0042] Simultaneous installation of multiple parallel devices: Multiple multi-compartment box devices containing mineral bag arrays were buried at one time in the same treatment plot, and the multiple multi-compartment box devices were respectively assigned to different sampling years.

[0043] In one specific implementation, five multi-compartment box devices are buried simultaneously within the same treatment plot. These five devices are labeled Y1, Y2, Y3, Y4, and Y5, corresponding to destructive sampling in the 1st, 2nd, 3rd, 4th, and 5th years, respectively. The distance between adjacent multi-compartment box devices is no less than 50 cm. This distance is used to reduce the mutual influence of root disturbance, soil moisture disturbance, and sampling disturbance between adjacent devices.

[0044] The purpose of burying multiple parallel devices at once is to ensure that devices from different sampling years are buried at the same initial time, in the same treatment plot, and under the same treatment conditions. During annual sampling, each multi-compartment box device is sampled only once, without backfilling or reuse. This avoids root damage, soil structure disturbance, changes in microbial communities, and sample residue problems caused by repeatedly opening the same device. Compared to repeatedly sampling the same device, this embodiment forms a multi-year data sequence through independent devices in each year, ensuring that the data obtained from year 1 to year 5 all originate from independently buried objects that have not been disturbed by sampling in the previous year.

[0045] In different treatment plots, the same number of devices, the same array of mineral bags, and the same annual sampling plan can be used. For example, the same number of multi-compartment boxes can be buried at once in control, warming, grazing, and recovery plots. By keeping the device specifications, mineral material type, burial depth, and sampling year consistent, the increase in mineral-bound organic carbon between different treatments can be made comparable.

[0046] In-situ burial in the wild: In representative plots of the ecosystem to be evaluated, burial chambers were excavated according to the main dimensions of the enclosure. As one specific implementation, the burial chamber was 30 cm deep, 12 cm long, and slightly wider than the main enclosure to accommodate the multi-compartment enclosure device. During excavation, the surrounding soil structure was kept as intact as possible to avoid excessive disturbance to the surrounding root system.

[0047] The multi-compartment box device containing the mineral bag array was placed in the burial chamber, with the top of the box body flush with or nearly flush with the ground surface. During placement, the depth direction of the box body was aligned with the vertical direction of the soil, with the three compartments corresponding to the 0-10cm, 10-20cm, and 20-30cm soil layers, respectively. The integrated transparent cover was closed and secured with clips or screws. The gaps around the box body were then backfilled with in-situ soil, and the backfill was lightly pressed to ensure contact between the sidewalls of the box body and the surrounding soil. No exogenous organic matter was added to the mineral bags during backfilling to ensure that the measured increase in organic carbon primarily originated from in-situ rhizosphere input.

[0048] After installation, a marker pole is installed on or near the top of the container body. The marker pole records the sample plot number, device number, and corresponding sampling year. The marker pole is used to accurately locate the corresponding device during annual sampling and avoids mistakenly sampling multi-compartment container devices from different years.

[0049] During burial, plant roots can enter the interior of the container body through perforations in the side walls and partitions. Roots can grow around the mineral bags, and rhizosphere solution, dissolved organic matter, and microbial transformation products can enter the mineral bags through the mesh openings, coming into contact with the standardized mineral materials and undergoing adsorption, binding, or mineral protection processes. Thus, the standardized mineral materials within the mineral bags can record the increase in newly formed mineral-bound organic carbon at different depths, with different mineral types, and under different treatment conditions.

[0050] Annual destructive sampling and mineral bag recycling: According to the preset annual sampling plan, the corresponding multi-compartment box device is taken out in each sampling year. As a specific implementation, the multi-compartment box device corresponding to Y1 is taken out in the first year, the multi-compartment box device corresponding to Y2 is taken out in the second year, the multi-compartment box device corresponding to Y3 is taken out in the third year, the multi-compartment box device corresponding to Y4 is taken out in the fourth year, and the multi-compartment box device corresponding to Y5 is taken out in the fifth year.

[0051] During sampling, first remove a small amount of soil covering the top of the device and confirm the device number and sampling year. Then, holding the portable handle, remove the multi-compartment device corresponding to the sampling year from the soil as a whole. During removal, try to keep the main body of the device stable and avoid moving the mineral bags in different compartments.

[0052] Place the removed multi-compartment enclosure on a clean tray and open the integrated transparent cover to simultaneously expose all compartments. Observe and record the distribution of plant roots in each compartment, including whether the roots have entered the main body of the enclosure, the main depth of root distribution, whether the roots are entangled in the mineral bags, and the relative density of roots in different compartments. These records are used to help interpret the differences in the increase of mineral-bound organic carbon at different depths.

[0053] Remove the mineral bags sequentially according to their compartment depth. Immediately after removal, place the mineral bags into the corresponding numbered sample bags or sample boxes. The sample number should include at least the treatment plot number, apparatus number, sampling year, compartment depth, and mineral material type.

[0054] In this embodiment, the annual destructive sampling is not a simple repeated sampling step, but rather a combination of multiple parallel devices buried at once to form a multi-year independent sample sequence. Each device corresponds to only one sampling year, and after sampling, it is not returned to the soil for use, thereby avoiding annual disturbances introduced by repeatedly opening the same device.

[0055] To avoid ambiguity caused by absolute zero baseline representation, this embodiment uses the pre-burial organic carbon baseline value for subtraction. The pre-burial organic carbon baseline value was measured from standardized mineral materials of the same batch, mineral type, and treatment process but not buried. The increase in mineral-bound organic carbon at the corresponding burial time is calculated according to the following formula: ; in, Indicates the mineral type as , burial depth is The number of years buried is The increase in mineral-bound organic carbon at that time, expressed in mgC / g mineral; Indicates the mineral type as , burial depth is The number of years buried is The organic carbon content of the recovered sample is measured in mgC / g mineral; Indicates the mineral type as The baseline value of organic carbon, measured before burial, corresponds to the same batch of standardized mineral materials. The unit is mgC / g mineral. Indicates the type of mineral material; Indicates the burial depth or the corresponding compartment depth; Indicates the number of years it has been buried.

[0056] In this application, the increase in mineral-bound organic carbon refers to the increase in organic carbon formed on the mineral surface or related protected sites after inorganic carbon removal, following the entry of rhizosphere solution, dissolved organic matter, and microbial transformation products into the mineral bag during in-situ burial of standardized mineral materials. By subtracting the baseline value of organic carbon before burial, the measurement results can more accurately correspond to the newly formed stable carbon components during burial.

[0057] Obtaining mineral-bound organic carbon accumulation data and interannual increment series: Based on the increase in mineral-bound organic carbon (BOC) for different sampling years, cumulative data on the change of BOC over burial time is obtained. For example, device Y1 provides the BOC increase for year 1, device Y2 provides the BOC increase for year 2, device Y3 provides the BOC increase for year 3, device Y4 provides the BOC increase for year 4, and device Y5 provides the BOC increase for year 5. Since devices Y1 to Y5 are buried in the same treatment plot at once, and each device corresponds to a different sampling year, the above data can constitute multi-year cumulative data under the same treatment conditions.

[0058] An interannual increment sequence is formed based on the difference in mineral-bound organic carbon increments between adjacent sampling years. The interannual increment is calculated using the following formula: ; in, Indicates the mineral type as , burial depth is , No. From the year to the year Interannual increase in mineral-bound organic carbon between years, in mgC / g mineral; Indicates the first The increase in mineral-bound organic carbon obtained during annual sampling; Indicates the first The increase in mineral-bound organic carbon obtained during annual sampling; Indicates the sampling year sequence number, and Greater than 1. When calculating the increment in year 1 relative to pre-burial levels, the increment of mineral-bound organic carbon in year 1 can be used as the cumulative amount for year 1. If the average accumulation rate needs to be calculated, it can be calculated using the following formula: ; in, Indicates the mineral type as , burial depth is The number of years buried is The average accumulation rate over time, expressed in mgC / g mineral / year; This represents the increase in mineral-bound organic carbon over a corresponding number of burial years; Indicates the number of years it has been buried.

[0059] In the above formula, Used to characterize the cumulative formation amount in different years, Used to characterize the amount of new formation between adjacent years. These three metrics are used to characterize the average carbon pool formation capacity per unit time. They correspond to cumulative level, annual variation, and average rate, respectively, and can reflect the ecosystem's capacity to form a stable carbon pool from different perspectives.

[0060] Assessment of stable carbon pool formation capacity and mineral carbon saturation state: Based on cumulative data and interannual increment sequences, the stable carbon pool formation capacity of the ecosystem to be assessed is determined, and the mineral carbon saturation state is determined based on the changing trends of the interannual increment sequences.

[0061] If, in a given treatment plot, under the same mineral material type and burial depth, the increase in mineral-bound organic carbon continuously increases with burial time, it indicates that a stable carbon formation process still exists under that treatment condition. If the interannual increment sequence under that treatment condition remains at a high level, it indicates that the corresponding ecosystem still possesses a strong capacity for stable carbon pool formation. If, among different treatment plots, the increase in mineral-bound organic carbon under a given treatment... , or If the result is significantly higher than the other treatment, it can be determined that the treatment is more conducive to the formation of mineral-bound organic carbon.

[0062] The carbon saturation state of minerals can be determined using interannual increment sequences. When the bound organic carbon in minerals continuously increases with burial time, and the interannual increment sequence shows a decreasing trend, it indicates that the effective sites for the continued binding of new organic carbon on the mineral material are gradually decreasing, confirming a trend towards mineral carbon saturation. When the bound organic carbon in minerals increases approximately linearly with burial time, and the interannual increment between adjacent years does not show a continuously decreasing trend, it can be determined that the mineral carbon saturation state has not yet been reached.

[0063] To avoid misinterpreting abnormal fluctuations in a single year as a saturation trend, in practice, data from multiple consecutive years can be used for judgment. For example, if data from years 2 to 5 is complete, and the data is from the same treatment, depth, and mineral type... , and If the overall trend is downward, the mineral carbon saturation trend can be considered relatively clear. If individual fluctuations occur between years due to abnormal factors such as precipitation, temperature, or root growth, a comprehensive judgment can be made by combining the results of quadrat replications and root observation records.

[0064] In this embodiment, the determination of mineral carbon saturation does not directly rely on the total organic carbon content of natural soil, but rather on the cumulative data and interannual increment sequence of mineral-bound organic carbon formed over time in the in-situ environment by standardized mineral materials. This determination method can avoid the problems of high background organic carbon in natural soil, dilution of short-term changes, and strong spatial heterogeneity among different sampling points.

[0065] Assessment of the impact of carbon sequestration under different treatment conditions: By repeating the above steps in different treatment plots, the ecosystem's ability to form stable carbon pools under different treatment conditions can be compared. For example, the same multi-compartment enclosure and mineral bag array can be set up in natural control plots, warming treatment plots, nitrogen-added treatment plots, grazing treatment plots, enclosure restoration plots, or reseeding restoration plots.

[0066] When making comparisons, it is important to maintain consistency in apparatus specifications, compartment depth, mineral material type, mineral bag quality, mesh bag aperture, burial date, and sampling date among different treatment plots. This way, differences between treatments primarily reflect the impact of treatment conditions on rhizosphere carbon input, microbial transformation, and mineral binding processes, rather than deviations caused by differences in apparatus parameters or sampling procedures.

[0067] For each treated sample plot, calculations can be performed separately for different mineral material types, different compartment depths, and different sampling years. , and When a treatment exhibits a higher increase or average accumulation rate of mineral-bound organic carbon compared to the control treatment, it indicates that the treatment promotes the formation of a stable carbon pool. Conversely, when a treatment exhibits a lower increase or average accumulation rate of mineral-bound organic carbon compared to the control treatment, it indicates that the treatment weakens the ability to form a stable carbon pool.

[0068] The difference evaluation in this embodiment is based on standardized mineral materials in the mineral bag, rather than directly using the total organic carbon of natural soil as the sole indicator. Therefore, even if the total organic carbon of natural soil does not change significantly in the short term, this embodiment can still capture the impact of treatment conditions on the stable carbon formation process by measuring the incremental organic carbon formed on the standardized mineral materials.

[0069] Example 2 Control quadrats, warming treatment quadrats, grazing treatment quadrats, and reseeding restoration quadrats were established within the alpine meadow study area. Multiple replicate quadrats were set up for each treatment. Five multi-compartment boxes were embedded in each quadrat at once, labeled Y1, Y2, Y3, Y4, and Y5, corresponding to destructive sampling from year 1 to year 5, respectively. The distance between adjacent multi-compartment boxes was no less than 50 cm.

[0070] Each multi-compartment enclosure has a main body depth of 30cm and is internally divided into three compartments along the soil depth direction, corresponding to soil layers of 0-10cm, 10-20cm, and 20-30cm, respectively. The main body sidewalls and partition structures are perforated with holes of 5-8mm in diameter. The front of the enclosure features a single, transparent cover that covers all compartments, a portable handle is located at the top, and a closed bottom plate is installed at the bottom.

[0071] The mineral bags are nylon mesh bags with a pore size of 53μm. Each mineral bag contains 15.0g of standardized mineral material. The bags are 9cm long and 4cm wide. The standardized mineral materials are low-reactive, medium-reactive, and high-reactive. The low-reactive mineral material is a mixture of kaolin and acid-washed quartz sand in a 50:50 mass ratio. The medium-reactive mineral material is a mixture of montmorillonite and acid-washed quartz sand in a 50:50 mass ratio. The high-reactive mineral material is hydrated iron oxide-coated quartz sand or a composite material of goethite and montmorillonite.

[0072] In one arrangement, three compartments of the same multi-compartment enclosure hold the same reactive mineral bags to compare the differences in mineral-bound organic carbon accumulation of the same mineral material at different soil depths. Different types of mineral materials can be tested separately in different multi-compartment enclosures to avoid interference from differences in mineral type within the same enclosure on depth distribution analysis.

[0073] During installation, the multi-compartment device is placed in a burial chamber matching its size, ensuring the top of the main body is flush with the ground surface. The integrated transparent cover is closed, and the original soil is backfilled and lightly compacted to ensure contact between the main body of the device and the surrounding soil. One year after burial, the Y1 device is removed for destructive sampling. During sampling, the entire device is removed using a portable handle, the integrated transparent cover is opened, and the three compartments are exposed simultaneously. Mineral bags are then removed from the 0-10cm, 10-20cm, and 20-30cm compartments, respectively.

[0074] After recovering the mineral bags, the standardized mineral materials inside were treated with 1M hydrochloric acid, centrifuged, washed, freeze-dried, and analyzed using an elemental analyzer. The increase in mineral-bound organic carbon was calculated based on the difference between the recovered organic carbon content and the baseline organic carbon value before burial.

[0075] In the one-year field burial results provided, the increase in mineral-bound organic carbon in highly reactive mineral materials was higher than that in low-reactive mineral materials, and the accumulation in the corresponding compartments of the surface soil was higher than that in the corresponding compartments of the deep soil. These results indicate that the multi-compartment mineral bag array of this application can simultaneously reflect the influence of differences in mineral material type and soil depth on the stable carbon formation process. This difference cannot be stably obtained simply by detecting the total organic carbon in natural soil, but depends on the combined setup of standardized mineral bags, fixed-depth compartments, and long-term in-situ burial.

[0076] Example 3 This embodiment provides an implementation method for determining the carbon saturation state of minerals using a five-year continuous burial design.

[0077] Five multi-compartment box devices were buried in the same treatment plot at one time, and the five devices were labeled Y1, Y2, Y3, Y4 and Y5 respectively. The box structure, number of compartments, mineral bag size, mineral material type and burial depth of each device were consistent. Y1 corresponds to the sampling in the first year, Y2 to the sampling in the second year, Y3 to the sampling in the third year, Y4 to the sampling in the fourth year, and Y5 to the sampling in the fifth year.

[0078] Only the corresponding year's apparatus is removed for each sampling year. For example, Y1 is removed in year 1, Y2 in year 2, Y3 in year 3, Y4 in year 4, and Y5 in year 5. The removed apparatus is not put back into the soil. In this way, the data for the five years come from five independent apparatuses, avoiding soil structure disturbance, root damage, and changes in the position of mineral bags caused by repeatedly opening the same apparatus.

[0079] The same pretreatment and organic carbon determination were performed on the recycled mineral bags each year, and the results were calculated. , , , and Calculated based on the difference between adjacent years. , , and .

[0080] when It continues to rise with each passing year, but When the amount gradually decreases over time, it indicates that the standardized mineral material is still forming mineral-bound organic carbon, but the amount of newly formed carbon is gradually decreasing, suggesting that the mineral material is trending towards carbon saturation. It increases almost linearly with the number of years, and If there is no continuous decreasing trend, it can be determined that the mineral material has not yet reached mineral saturation within the current burial period.

[0081] This embodiment combines the simultaneous installation of multiple parallel devices with annual destructive sampling to create a series of independent samples that can be compared across different years. This approach differs from repeatedly sampling soil at the same location to determine total organic carbon, and also from obtaining only one endpoint data point after burying mineral bags in a single year. It can obtain the cumulative curve and interannual increment sequence of mineral-bound organic carbon, thus providing continuous data for determining the formation rate of stable carbon pools and the trend of mineral carbon saturation.

[0082] Example 4 This embodiment provides an implementation method for assessing the impact of ecological restoration measures on the ability of stable carbon pools to form using the method of this application.

[0083] Within the degraded grassland study area, degraded control quadrats, enclosure restoration quadrats, reseeding restoration quadrats, and reseeding and fertilization restoration quadrats were set up. Multiple replicate quadrats were set up for each treatment. Five multi-compartment box devices were buried in each quadrat at one time. The device structure, compartment depth, mineral bag specifications, and sampling year settings were all the same as in Example 1.

[0084] To improve the sensitivity of detecting the impact of restoration measures, highly reactive mineral bags can be placed in each compartment. Highly reactive mineral materials have a strong binding capacity for dissolved organic matter and microbial transformation products, making them suitable for comparing the effects of different restoration measures on the formation capacity of mineral-bound organic carbon. After one year of burial, the Y1 device in each treatment plot was removed, the mineral bags in each compartment were recovered, and the increase in mineral-bound organic carbon was calculated using the same pretreatment and measurement methods.

[0085] When comparing different restoration measures, such as enclosure restoration plots, reseeding restoration plots, or reseeding and fertilization restoration plots... If the increase is higher than that in the degraded control plot, it indicates that the corresponding restoration measures increased the amount of newly formed organic carbon on the standardized mineral material. If the increase in the surface compartment is also higher than that in the deep compartment, the root distribution record can be used to determine whether the restoration measures mainly promoted the formation of stable carbon by increasing the input of surface roots.

[0086] The evaluation object of this embodiment is not the single effect of restoration measures on aboveground vegetation, nor the small changes in total organic carbon in natural soil in the short term, but rather the increase in mineral-bound organic carbon formed by rhizosphere carbon input and mineral binding processes under the action of restoration measures. Since all treatments use the same standardized mineral materials and the same burial structure, the results between different treatments are more comparable.

[0087] Example 5 This embodiment illustrates the technical differences between this application and conventional solutions, and the basis for its implementation in the implementation method.

[0088] Conventional soil carbon monitoring typically involves directly collecting natural soil samples and determining the total organic carbon content. In this method, the background organic carbon content of natural soil is relatively high, and newly added organic carbon in the short term is easily diluted by the background organic carbon. At the same time, soil exhibits spatial heterogeneity in both the horizontal and vertical directions, and the sampling locations in different years are difficult to be completely consistent, resulting in large fluctuations in the results.

[0089] This application uses standardized mineral materials that have undergone carbon removal treatment and have had their pre-burial organic carbon baseline values ​​measured as carbon-binding carriers. After recovery, the increase in mineral-bound organic carbon is obtained by subtracting the baseline. This method transforms the assessment object from the change in total organic carbon in natural soil to the increase in newly formed organic carbon on standardized mineral materials, thereby reducing the impact of background carbon in natural soil on short-term change detection.

[0090] Conventional mineral bag burial schemes may simply involve burying mineral bags directly in the soil to obtain endpoint measurement results at a specific point in time. This method struggles to simultaneously ensure stable mineral bag depth, independent sampling across different years, unified retrieval of samples from different depths, and continuous comparability of data over multiple years. This application utilizes a multi-compartment enclosure to fix the depth of mineral bags, a unified transparent cover for the retrieval of mineral bags from different compartments, and the simultaneous burial of multiple parallel devices with destructive sampling each year to create an annual independent sample sequence. The synergy of these structures and processes enables this application to obtain cumulative data and interannual incremental sequences, rather than just single endpoint data.

[0091] Therefore, the technical solution of this application achieves synergy in at least the following aspects: the multi-compartment box device solves the problem of locating mineral bags at different depths; the standardized mineral bags solve the problem of inconsistency between background carbon and mineral types; the simultaneous installation of multiple parallel devices solves the problem of annual sampling disturbance; annual destructive sampling solves the problem of long-term dynamic data acquisition; and baseline subtraction and interannual increment sequences solve the problem of quantitatively judging the stable carbon pool formation capacity and mineral carbon saturation state. When the above features exist in parallel, a long-term, in-situ, standardized, and comparable ecosystem carbon sequestration assessment process can be formed.

[0092] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for in-situ assessment of ecosystem carbon sequestration based on multi-compartment mineral bag arrays, characterized in that, Includes the following steps: S1: Prepare a multi-compartment box device. The multi-compartment box device includes a box body, a partition structure set inside the box body, and an openable transparent cover set on the box body. The partition structure divides the internal space of the box body into multiple compartments along the soil depth direction. The side walls of the box body and the partition structure are provided with perforated holes for plant roots, soil solution and microorganisms to enter. S2: Prepare standardized mineral bags by encapsulating standardized mineral materials with an initial organic carbon content of zero in a water-permeable and solute-permeable mesh bag to form a mineral bag for adsorbing and stabilizing newly introduced organic carbon. S3: Construct a mineral bag array, place multiple mineral bags in different compartments of the multi-compartment box device, and record the burial depth and mineral material type of each mineral bag. S4: Multiple multi-compartment box devices containing mineral bag arrays are buried at one time in the same treatment plot, and the multiple multi-compartment box devices are respectively assigned to different sampling years; S5: Bury the multi-compartment box device in situ in the soil of the ecosystem to be evaluated, so that the main body of the box is in contact with the surrounding soil and the plant roots can enter the main body of the box through the perforated holes and come into contact with the mineral bag. S6: According to the preset annual sampling plan, the corresponding multi-compartment box device is taken out in each sampling year, and the mineral bags in each compartment are recycled by opening the openable transparent cover. S7: Pre-treat the mineral materials in the recovered mineral bags and determine the organic carbon content in the mineral materials. Use the measured organic carbon content as the increment of newly formed mineral-bound organic carbon under this burial time. S8: Based on the increase in mineral-bound organic carbon corresponding to different sampling years, obtain the cumulative data of mineral-bound organic carbon changes with burial time, and calculate the accumulation rate of mineral-bound organic carbon. S9: Based on the accumulated data and accumulation rate, determine whether the accumulation of mineral-bound organic carbon tends to level off, and assess the stable carbon pool formation capacity and mineral carbon saturation status of the ecosystem to be assessed.

2. The method for in-situ assessment of ecosystem carbon sequestration based on multi-compartment mineral bag arrays according to claim 1, characterized in that, The main body of the box is made of acrylic and is set along the soil depth direction. The partition structure divides the internal space of the main body of the box into three compartments, which correspond to the surface soil, the middle soil and the deep soil, respectively.

3. The method for in-situ assessment of ecosystem carbon sequestration based on multi-compartment mineral bag arrays according to claim 2, characterized in that, The main body of the box is buried at a depth of 30cm, and the three compartments correspond to the soil layers of 0 to 10cm, 10 to 20cm and 20 to 30cm respectively along the soil depth direction. The diameter of the perforated holes on the side wall of the main body of the box is 5 to 8 mm, and the hole spacing is 5 mm (the spacing is changed to 5 mm, otherwise there are too few holes on the side wall). The diameter of the perforated holes on the partition structure is 5 to 8 mm. (The aperture can be the same).

4. The method for in-situ assessment of ecosystem carbon sequestration based on multi-compartment mineral bag arrays according to claim 3, characterized in that, The openable transparent cover is an integral transparent cover that covers all compartments. The integral transparent cover is connected to the main body of the box by buckles or screws, and a sealing gasket is provided at the connection. In step S6, after opening the integral transparent cover, all compartments are exposed simultaneously to uniformly collect the mineral bags in different compartments and observe the root distribution in each compartment.

5. The method for in-situ assessment of ecosystem carbon sequestration based on multi-compartment mineral bag arrays according to claim 4, characterized in that, In step S2, the standardized mineral material is selected from one of low-reactivity mineral materials, medium-reactivity mineral materials, and high-reactivity mineral materials; The low-reactive mineral material is a mixture of kaolin and acid-washed quartz sand in a mass ratio of 50:50; The medium reactive mineral material is a mixture of montmorillonite and acid-washed quartz sand in a mass ratio of 50:50; The highly reactive mineral material is hydrated iron oxide-coated quartz sand, or a composite material formed by goethite and montmorillonite.

6. The method for in-situ assessment of ecosystem carbon sequestration based on multi-compartment mineral bag arrays according to claim 5, characterized in that, In step S2, each mineral bag contains 15.0g of standardized mineral material. The mesh bag is a nylon mesh bag with a pore size of 53μm. The mineral bag is 9cm long and 4cm wide. After being sterilized by high-pressure steam at 121℃ for 30min, the mineral bags are used for in-situ burial.

7. The method for in-situ assessment of ecosystem carbon sequestration based on multi-compartment mineral bag arrays according to claim 6, characterized in that, In step S3, the mineral bag array is arranged in any of the following ways: The first arrangement involves placing mineral bags with different reactivity in different compartments of the same multi-compartment box device to simultaneously compare the effects of mineral material type and burial depth on the formation of mineral-bound organic carbon. The second arrangement involves placing the same reactive mineral bags in different compartments of the same multi-compartment box device to compare the differences in the accumulation of mineral-bound organic carbon of the same mineral material at different soil depths.

8. The method for in-situ assessment of ecosystem carbon sequestration based on multi-compartment mineral bag arrays according to claim 7, characterized in that, In step S4, five multi-compartment box devices are buried at one time in the same treatment plot. The five multi-compartment box devices are marked as Y1, Y2, Y3, Y4 and Y5 respectively, and correspond to the destructive sampling in the 1st, 2nd, 3rd, 4th and 5th years respectively; the distance between two adjacent multi-compartment box devices is not less than 50cm. In step S6, the multi-compartment box device corresponding to Y1 is taken out in the first year, the multi-compartment box device corresponding to Y2 is taken out in the second year, the multi-compartment box device corresponding to Y3 is taken out in the third year, the multi-compartment box device corresponding to Y4 is taken out in the fourth year, and the multi-compartment box device corresponding to Y5 is taken out in the fifth year. Each multi-compartment box device is subjected to destructive sampling only once, so that the mineral bag samples obtained in different years are all independent buried samples.

9. A method for in-situ assessment of ecosystem carbon sequestration based on a multi-compartment mineral bag array according to claim 8, characterized in that, In step S8, the accumulation rate of mineral-bound organic carbon includes the interannual accumulation rate and the average accumulation rate; The interannual accumulation rate is obtained by subtracting the mineral-bound organic carbon content of the previous sampling year from the mineral-bound organic carbon content of the subsequent sampling year. The average accumulation rate is obtained by dividing the mineral-bound organic carbon content in the nth sampling year by the number of burial years n; In step S9, when the mineral-bound organic carbon continuously increases with the increase of burial time and the annual increment decreases year by year, it is determined that there is a mineral carbon saturation trend. When the mineral-bound organic carbon increases linearly with burial time, it is determined that the mineral carbon saturation state has not yet been reached. The maximum carbon adsorption capacity of the corresponding mineral material was determined by fitting the accumulated data using an adsorption model.

10. A method for in-situ assessment of ecosystem carbon sequestration based on a multi-compartment mineral bag array according to claim 9, characterized in that, Step S9 is followed by a disturbance impact assessment step: the increase in mineral-bound organic carbon, the accumulation rate of mineral-bound organic carbon, and the mineral carbon saturation state obtained under different treatment plots are compared to assess the impact of one of the following treatment factors on the ability of the ecosystem to form a stable carbon pool: climate warming, nitrogen addition, drought treatment, grazing treatment, enclosure restoration, and reseeding restoration. In the disturbance impact assessment step, the increase in mineral-bound organic carbon is used as the direct response variable, and a multi-factor variance analysis is conducted in combination with the treatment type, mineral material type and burial depth to obtain the differences in the impact of different treatment factors, different mineral material types and different soil depths on the ability to form a stable carbon pool.

Images