A method and system for evaluating soil conservation and carbon sequestration capacity of a small watershed

Abstract

This application provides a method and system for assessing the soil conservation and carbon sequestration capacity of a small watershed, belonging to the field of soil and water conservation technology. The method includes: obtaining monitoring data of the small watershed during a baseline period before the implementation of soil and water conservation measures and during an assessment period after implementation, wherein the baseline period and the assessment period are of the same length; determining the in-situ and ex-situ soil conservation and carbon sequestration amounts of the small watershed based on the monitoring data; and determining the total soil conservation and carbon sequestration amount of the small watershed based on the in-situ and ex-situ soil conservation and carbon sequestration amounts. This application quantifies the erosion reduction and carbon sequestration benefits through in-situ soil conservation and carbon sequestration benefits through ex-situ soil conservation, thus overcoming the shortcomings of existing methods that cannot accurately calculate the carbon neutrality contribution of small watersheds due to limitations in assessment scale, and overcoming the problem of systematically underestimated assessment results.

Description

Technical Field

[0001] This application relates to the field of soil and water conservation technology, and in particular to a method and system for assessing the soil conservation and carbon sequestration capacity of a small watershed. Background Technology

[0002] In the context of global climate change response, the scientific and accurate quantification of the contribution of soil and water conservation projects to carbon sinks in terrestrial ecosystems is of significant technical importance for objectively evaluating the effectiveness of these efforts and supporting relevant policy formulation. Among these efforts, the systematic management of soil erosion in small watersheds plays a crucial role in reducing soil erosion intensity, enhancing the stability of terrestrial ecosystems, and strengthening their carbon sink capacity. Therefore, quantifying the soil conservation and carbon sequestration capacity generated by soil erosion control in small watersheds is both an objective necessity for objectively evaluating the effectiveness of watershed soil erosion control and a practical requirement for quantifying the contribution of soil and water conservation to carbon neutrality. This can provide methodological basis and data support for assessing the carbon neutrality contribution of soil and water conservation.

[0003] Small watersheds are complex hydrological systems that include various geomorphic units and soil and water conservation measures. However, existing methods for assessing soil carbon sequestration capacity evaluate isolated plots as units. Their assessment mechanisms only focus on the soil carbon sinks retained in place due to reduced erosion, ignoring the cumulative effect of multiple soil and water conservation measures within the small watershed. This limitation of the assessment scale makes it impossible to accurately calculate the contribution of soil and water conservation to carbon neutrality in small watersheds, resulting in systematic biases in the final assessment results. Summary of the Invention

[0004] This application provides a method and system for assessing the soil conservation and carbon sequestration capacity of small watersheds, aiming to solve the problem that existing methods for assessing soil conservation and carbon sequestration capacity cannot accurately calculate the carbon neutrality contribution of soil and water conservation in small watersheds, resulting in systematic bias in the final assessment results.

[0005] Firstly, this application provides a method for assessing the soil conservation and carbon sequestration capacity of a small watershed, including: The monitoring data of the small watershed are obtained during the baseline period before the implementation of soil and water conservation measures and the evaluation period after the implementation, wherein the baseline period and the evaluation period are of the same length; Based on the monitoring data, the in-situ and ex-situ soil carbon sequestration amounts in the small watershed were determined. The total amount of soil and carbon sequestration in the small watershed is determined based on the in-situ soil and carbon sequestration amount and the ex-situ soil and carbon sequestration amount. The in-situ soil carbon sequestration capacity represents the amount of carbon fixed by the soil that is retained in place due to the decrease in the soil erosion modulus; the ex-situ soil carbon sequestration capacity represents the amount of carbon mineralization loss avoided by the soil that was eroded during the assessment period and intercepted in the small watershed due to the decrease in the sediment transport ratio.

[0006] In one embodiment, the monitoring data includes the soil erosion modulus and sediment transport ratio of the small watershed corresponding to the baseline period and the assessment period; the small watershed includes untreated plots and treated plots, wherein the treated plots are plots for which soil and water conservation measures are implemented during the assessment period; Accordingly, determining the ex-situ soil carbon sequestration amount of the small watershed based on the monitoring data includes: The comprehensive organic carbon content of the small watershed during the assessment period is determined based on the soil organic carbon content of the treated plots and the soil organic carbon content of the untreated plots during the assessment period. The ex-situ soil carbon sequestration amount is obtained based on the soil organic carbon mineralization ratio during the soil erosion process, the first difference between the sediment transport ratio during the baseline period and the sediment transport ratio during the assessment period, the area of ​​the small watershed, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content.

[0007] In one embodiment, determining the in-situ soil carbon sequestration of the small watershed based on the monitoring data includes: The in-situ soil carbon sequestration amount is obtained based on the soil organic carbon content of the treated plot during the assessment period, the area of ​​the small watershed, and the second difference between the soil erosion modulus of the baseline period and the soil erosion modulus of the assessment period.

[0008] In one embodiment, determining the total soil and carbon sequestration of the small watershed based on the in-situ soil and carbon sequestration amount and the ex-situ soil and carbon sequestration amount includes: Determine the sum of the in-situ soil-conserving carbon fixation amount and the ex-situ soil-conserving carbon fixation amount; The total amount of carbon sequestration in soil conservation is obtained by correcting the sum using the risk factors of soil and water conservation measures.

[0009] In one embodiment, obtaining the ex-situ soil carbon sequestration amount based on the soil organic carbon mineralization ratio during soil erosion, a first difference between the sediment transport ratio during the baseline period and the sediment transport ratio during the assessment period, the area of ​​the small watershed, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content includes: The soil organic carbon mineralization ratio, the first difference, the area of ​​the small watershed, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content are multiplied to obtain the ex-situ soil carbon sequestration amount.

[0010] In one embodiment, the in-situ soil carbon sequestration is obtained based on the soil organic carbon content of the treated area during the assessment period, the area of ​​the small watershed, and a second difference between the soil erosion modulus of the baseline period and the soil erosion modulus of the assessment period, including: The soil organic carbon content of the treated plot, the area of ​​the small watershed, and the second difference are multiplied together to obtain the in-situ soil carbon sequestration amount.

[0011] In one embodiment, determining the combined organic carbon content of the small watershed during the assessment period based on the soil organic carbon content of the treated plot and the untreated plot includes: The area of ​​the treated land and the weight of the untreated land are determined based on the area of ​​the treated land and the area of ​​the untreated land, respectively. The weighted average of the soil organic carbon content of the treated plot and the soil organic carbon content of the untreated plot is determined based on the weights, and is taken as the comprehensive organic carbon content.

[0012] Secondly, this application also provides a soil conservation and carbon sequestration capacity assessment system for small watersheds, comprising: The monitoring data acquisition module is used to acquire monitoring data of the small watershed during the baseline period before the implementation of soil and water conservation measures and the evaluation period after the implementation, wherein the baseline period and the evaluation period have the same duration; The first soil carbon sequestration determination module is used to determine the in-situ and ex-situ soil carbon sequestration of the small watershed based on the monitoring data. The in-situ soil carbon sequestration represents the amount of carbon fixed by the soil retained in place due to the decrease in the soil erosion modulus. The ex-situ soil carbon sequestration represents the amount of carbon mineralization loss avoided by the soil that was eroded during the assessment period and intercepted in the small watershed due to the decrease in the sediment transport ratio. The second soil conservation and carbon sequestration determination module is used to determine the total amount of soil conservation and carbon sequestration in the small watershed based on the in-situ soil conservation and carbon sequestration amount and the ex-situ soil conservation and carbon sequestration amount.

[0013] Thirdly, this application also provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements any of the above-mentioned methods for assessing the soil conservation and carbon sequestration capacity of small watersheds.

[0014] Fourthly, this application also provides a non-transitory computer-readable storage medium storing a computer program, which, when executed by a processor, implements any of the above-mentioned methods for assessing the soil conservation and carbon sequestration capacity of small watersheds.

[0015] Fifthly, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements any of the above-mentioned methods for assessing the soil conservation and carbon sequestration capacity of small watersheds. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is one of the flowcharts illustrating the method for assessing the soil conservation and carbon sequestration capacity of small watersheds provided in this application; Figure 2 This is the second flowchart of the method for assessing the soil conservation and carbon sequestration capacity of small watersheds provided in this application; Figure 3 This is a schematic diagram of the process for determining the ex-situ soil conservation and carbon sequestration of the small watershed based on the monitoring data provided in this application; Figure 4 This is a schematic diagram of the process for determining the total amount of soil and carbon sequestration in the small watershed based on the in-situ soil and carbon sequestration amount and the ex-situ soil and carbon sequestration amount provided in this application. Figure 5 This is a schematic diagram of the structure of the soil conservation and carbon sequestration capacity assessment system for small watersheds provided in this application; Figure 6 This is a schematic diagram of the structure of the electronic device provided in this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that, in the description of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0020] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, without limiting the number of objects; for example, a first object can be one or more. Furthermore, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects have an "or" relationship.

[0021] Small watersheds are the basic unit for soil and water conservation. Each small watershed contains diverse landforms, and different landforms require different soil and water conservation measures. Therefore, soil and water conservation in small watersheds involves multiple measures. However, current assessments of soil conservation and carbon sequestration capacity are based on individual land parcels with specific soil and water conservation measures, which deviates from the practical reality of soil and water conservation being based on small watersheds. This makes it difficult to generalize and apply the assessment results.

[0022] Current methods for assessing soil carbon sequestration capacity evaluate isolated plots of land. Their assessment mechanisms focus solely on soil carbon sinks retained in situ due to reduced erosion, neglecting the cumulative effects of multiple soil and water conservation measures within a small watershed. Specifically, due to the implementation of various soil and water conservation measures within a small watershed, sediment transported from one plot may be intercepted by downstream plots, leading to a decrease in the sediment transport ratio within the watershed. This, in turn, reduces the actual mineralization of organic carbon during soil erosion and transport. Current methods fail to consider this cumulative effect, resulting in underestimated assessments.

[0023] Based on the above, this application provides a method and system for assessing the soil conservation and carbon sequestration capacity of small watersheds, which will be described in detail below with reference to the accompanying drawings.

[0024] The soil conservation and carbon sequestration capacity of a small watershed refers to the overall process within a small watershed that improves soil erosion resistance, retains soil, maintains soil organic carbon stability, and reduces soil organic carbon erosion, transport, mineralization, and loss through engineering, planting, and cultivation measures that have soil and water conservation functions.

[0025] It should be noted that the method for assessing the soil conservation and carbon sequestration capacity of small watersheds provided in this application is based on a system for assessing the soil conservation and carbon sequestration capacity of small watersheds. This method quantifies the erosion reduction and carbon sequestration benefits by measuring the amount of in-situ soil conservation and carbon sequestration, and quantifies the interception and carbon sequestration benefits by measuring the amount of ex-situ soil conservation and carbon sequestration. This method overcomes the shortcomings of existing methods that cannot accurately calculate the contribution of soil and water conservation to carbon neutrality in small watersheds due to the limitations of the assessment scale, and overcomes the problem of the systematic underestimation of the assessment results. This makes the assessment results more scientific and complete, and can more accurately reflect the actual contribution of soil and water conservation measures in small watersheds to carbon neutrality.

[0026] This application describes the method for assessing the soil conservation and carbon sequestration capacity of small watersheds using a small watershed soil conservation and carbon sequestration capacity assessment system as an example.

[0027] Figure 1 This is one of the flowcharts illustrating the method for assessing the soil conservation and carbon sequestration capacity of small watersheds provided in this application. For example... Figure 1 As shown, the method for assessing the soil carbon sequestration capacity of small watersheds provided in this application includes: S110: Obtain monitoring data for the small watershed during the baseline period before the implementation of soil and water conservation measures and the assessment period after implementation.

[0028] The reference period and the assessment period are of the same length to ensure that the data in the two periods are comparable and to eliminate assessment errors caused by seasonal or interannual climate fluctuations.

[0029] A small watershed is a complex hydrological system containing multiple geomorphic units. Therefore, different soil and water conservation measures can be taken for different geomorphic units within a small watershed. Thus, the assessment result of the soil conservation and carbon sequestration capacity of a small watershed is the comprehensive carbon sequestration benefit brought about by the superposition of multiple soil and water conservation measures.

[0030] Before assessing the soil conservation and carbon sequestration capacity of a small watershed, it is necessary to define the boundary of the watershed to be assessed and determine its area A. Subsequently, a survey should be conducted on the land use types, soil and water conservation measures, and the layout of hydrological control stations within the watershed to identify a list of all soil and water conservation measures with soil conservation and carbon sequestration functions. Then, based on this list, a detailed investigation of soil erosion control should be carried out to determine the implementation time of comprehensive soil erosion control projects, thereby establishing a baseline period and an assessment period. Remote sensing imagery, dynamic soil erosion monitoring data, and hydrological and sediment data from hydrological control stations should be collected for both the baseline and assessment periods to obtain monitoring data.

[0031] The baseline period is a time interval that represents the original or background state of a small watershed before comprehensive soil and water conservation measures are implemented. The year preceding the start of the project can be set as the baseline period. For example, if a small watershed begins implementing a national key soil and water conservation project in 2011, then the entire year of 2010 would be set as the baseline period.

[0032] The assessment period is a time interval that represents a small watershed after a period of management and after soil and water conservation measures have produced stable benefits. The current year of assessment can be set as the assessment period. For example, to assess the management effectiveness up to 2024, the entire year of 2024 can be set as the assessment period.

[0033] The monitoring data includes various types of raw or preprocessed information required for steps S120 and S130. The methods for obtaining monitoring data can be diverse. For example, it can be directly read from the water and soil conservation monitoring database of the water resources department or the historical database of hydrological stations; it can also be obtained by processing satellite remote sensing images of a specific time period and combining them with Geographic Information System (GIS) analysis; or it can be the result of integrating field surveys and sample collection and analysis.

[0034] These monitoring data may include, but are not limited to: watershed land use maps, vegetation cover data, digital elevation models, rainfall data, runoff and sediment transport data observed at hydrological stations, and organic carbon content measurements from soil samples. Through comprehensive analysis and model calculations of this basic monitoring data, core parameters required for assessment can be further derived, such as soil erosion modulus and sediment transport ratio.

[0035] S120: Determine the in-situ and ex-situ soil carbon sequestration amounts in the small watershed based on the monitoring data.

[0036] The in-situ soil carbon sequestration capacity represents the amount of carbon fixed by the soil that is retained in place due to the decrease in the soil erosion modulus; the ex-situ soil carbon sequestration capacity represents the amount of carbon mineralization loss avoided by the soil that was eroded during the assessment period and intercepted in the small watershed due to the decrease in the sediment transport ratio.

[0037] Specifically, by implementing soil and water conservation measures such as terracing and planting trees and grasslands, surface runoff can be directly slowed down and soil erosion resistance increased, i.e., the soil erosion modulus is reduced. This allows topsoil that would otherwise be lost to water erosion to be retained in its original location. Since topsoil is usually rich in organic carbon, the amount of organic carbon contained in this successfully retained soil constitutes the in-situ soil carbon sequestration. Specifically, the in-situ soil carbon sequestration can be determined based on the change in the soil erosion modulus of a small watershed.

[0038] Due to natural factors such as rainfall, soil erosion occurs to some extent within small watersheds. These eroded soil particles enter the water flow and begin to be transported. Thanks to the presence of comprehensive management measures within the small watershed (such as silt-retaining dams, dikes, and vegetation buffer zones), most of the eroded soil is intercepted and deposited in gullies, dammed areas, or slope toes before reaching the watershed outlet. This leads to a decrease in the overall watershed system's sediment transport capacity, i.e., a reduction in the sediment transport ratio, shortening the transport distance of eroded soil, and thus reducing carbon loss caused by soil organic carbon transport and mineralization.

[0039] According to the principles of soil biogeochemistry, soil organic carbon, during its long-distance and long-term transport with water flow, comes into full contact with water and air, undergoes mineralization and decomposition, and is released into the atmosphere as greenhouse gases such as carbon dioxide. By intercepting eroded soil and depositing it over a short distance within a small watershed, the transport path and time are greatly shortened, effectively avoiding the mineralization loss of this portion of organic carbon during transport. This successfully avoided carbon loss constitutes the ex-situ soil carbon sequestration. Specifically, the ex-situ soil carbon sequestration can be determined based on the change in the sediment transport ratio within the small watershed.

[0040] S130: Determine the total amount of soil and carbon sequestration in the small watershed based on the in-situ soil and carbon sequestration amount and the ex-situ soil and carbon sequestration amount.

[0041] Specifically, the in-situ and ex-situ soil carbon sequestration amounts can be mathematically aggregated, for example, by direct summation, to determine the total soil carbon sequestration amount. The total soil carbon sequestration amount can comprehensively reflect the overall carbon sequestration benefits of integrated small watershed management in terms of both erosion reduction and sediment interception.

[0042] This application's embodiments quantify the carbon sequestration and erosion reduction benefits by using in-situ soil conservation carbon sequestration and quantify the carbon interception and sequestration benefits by using ex-situ soil conservation carbon sequestration. This overcomes the shortcomings of existing methods that cannot accurately calculate the carbon neutrality contribution of soil and water conservation in small watersheds due to limitations in the assessment scale. It also overcomes the problem of the assessment results being systematically too small, making the assessment results more scientific and complete, and able to more accurately reflect the actual contribution of soil and water conservation measures in small watersheds to carbon neutrality.

[0043] In one possible implementation, the monitoring data includes the soil erosion modulus and sediment transport ratio of the small watershed corresponding to the baseline period and the assessment period. The small watershed includes untreated plots and treated plots, wherein the treated plots are those for which soil and water conservation measures were implemented during the assessment period.

[0044] Accordingly, please combine Figure 2 and Figure 3 In step S120, determining the ex-situ soil carbon sequestration amount in the small watershed based on the monitoring data includes: S310: Determine the comprehensive organic carbon content of the small watershed during the assessment period based on the soil organic carbon content of the treated plot and the untreated plot.

[0045] Specifically, based on the land use type of the small watershed and the identification results of the carriers of soil and water conservation measures, soil samples (0-30cm) of the topsoil of treated and untreated plots were collected (mainly involving cultivated land, orchards, forest land, grassland, etc.), and the soil organic carbon content was measured to obtain the soil organic carbon content of the treated plots and the untreated plots during the assessment period.

[0046] In one possible implementation, the arithmetic mean of the soil organic carbon content at each location on the treated plot during the assessment period is taken as the soil organic carbon content of the treated plot during the assessment period.

[0047] In one possible implementation, the comprehensive organic carbon content is determined by assigning corresponding weights to the contributions of treated and untreated plots to the total sediment yield of the small watershed, and then using a weighted method.

[0048] Therefore, the total organic carbon content can characterize the average organic carbon content level of soils in the entire small watershed that have undergone erosion and entered the transport process during the assessment period.

[0049] S320: The ex-situ soil carbon sequestration amount is obtained based on the soil organic carbon mineralization ratio during the soil erosion process, the first difference between the sediment transport ratio during the baseline period and the sediment transport ratio during the assessment period, the area of ​​the small watershed, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content.

[0050] The soil organic carbon mineralization ratio characterizes the proportion of soil organic carbon that decomposes into gaseous carbon dioxide during water transport. A fixed ratio can be preset based on previous research findings or industry recommendations for the region; for example, it can be preset to 0.2, meaning that 20% of organic carbon is considered to be mineralized during natural transport. The first difference quantifies the degree of improvement in sediment interception capacity brought about by comprehensive small watershed management. The larger the difference, the higher the sediment interception efficiency of the management measures. The soil erosion modulus for the assessment period characterizes the amount of soil erosion occurring per unit area and per unit time within the small watershed during the assessment period.

[0051] By comprehensively considering the soil organic carbon mineralization ratio, the first difference, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content, the amount of sediment successfully intercepted due to the reduced sediment transport ratio during the assessment period is quantified as the amount of carbon mineralization loss avoided by intercepting this portion of sediment.

[0052] The embodiments of this application obtain the amount of ex-situ soil carbon sequestration by comprehensively evaluating the reduction in soil erosion modulus, sediment transport ratio, soil carbon content, and carbon mineralization ratio over a comprehensive evaluation period. Through a clear and operable quantitative path, the feasibility of the evaluation method is significantly enhanced.

[0053] In one possible implementation, step S320, which involves obtaining the ex-situ soil carbon sequestration based on the soil organic carbon mineralization ratio during soil erosion, the first difference between the sediment transport ratio during the baseline period and the sediment transport ratio during the assessment period, the area of ​​the small watershed, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content, includes: The soil organic carbon mineralization ratio, the first difference, the area of ​​the small watershed, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content are multiplied to obtain the ex-situ soil carbon sequestration amount.

[0054] Specifically, the amount of carbon sequestration in ex-situ soil is calculated using the following formula: C S = M E ·A · (SDR) B -SDR E SOC A ·P (1) In the formula, C S The amount of carbon sequestration in situ in a small watershed is expressed in tC. M E To assess the soil erosion modulus of a small watershed over a given period, the average soil erosion modulus at various locations within the watershed during that period is typically taken, in t / km². 2 ·a; SDR B The sediment transport ratio of the small watershed during the baseline period is dimensionless. SDR E Dimensionless; A is the area of ​​the small watershed, in km². 2 ; SOC A To assess the overall organic carbon content of the small watersheds during the specified period, % . P represents the proportion of soil organic carbon mineralization during the soil erosion process, and is generally taken as 0.2.

[0055] in, SDR B =S B / M B (2) SDR E =S E / M E (3) In the formula, S B S E The annual sediment load of the small watershed is calculated by summing the daily sediment load observed at the outlet hydrological station of the small watershed, respectively, for the baseline period and the assessment period. The unit is t (tons).

[0056] If hydrological data is unavailable, the sediment transport ratio of the small watershed during the baseline period is SDR. B and the sediment transport ratio (SDR) of small watersheds during the assessment period E The sediment transport ratio can be obtained by referring to the values ​​of other small watersheds in the same or similar years in the same type of area.

[0057] Soil erosion modulus M in the small watershed during the assessment period E It can be obtained through field measurements, calculations using general soil loss equations, or dynamic monitoring data on soil and water loss from water conservancy departments.

[0058] Among them, the soil erosion modulus M during the assessment period E Multiplying this by the area A of the small watershed yields the total annual mass of soil entering the transport process across the entire small watershed during the assessment period. First Difference (SDR) B -SDR E This characterizes the degree of improvement in the interception capacity of the small watershed system. The first difference is multiplied by the total annual mass of soil entering the transport process throughout the entire small watershed during the assessment period to obtain the soil mass retained within the small watershed due to the interception effect of soil and water conservation measures; that is, the portion of the total erosion and sediment yield that was successfully intercepted due to soil and water conservation. The intercepted soil is then compared with the total organic carbon (SOC) content. A Multiply to obtain the total mass of organic carbon contained in the intercepted soil.

[0059] The proportion of soil organic carbon mineralization P during the soil erosion process represents the share of organic carbon lost due to decomposition during natural transport. Therefore, by multiplying the total mass of organic carbon mentioned above by the proportion of soil organic carbon mineralization P during the soil erosion process, we can obtain the amount of mineralization loss avoided by the intercepted organic carbon, which is the amount of ex-situ soil carbon sequestration.

[0060] The embodiments of this application clearly reveal the logical relationship and quantitative path between soil erosion, interception capacity improvement, soil carbon content and carbon mineralization loss rate during the assessment period by multiplying various parameters, making the assessment results highly transparent, reproducible and scientifically based.

[0061] In one possible implementation, step S310, determining the comprehensive organic carbon content of the small watershed during the assessment period based on the soil organic carbon content of the treated plot and the untreated plot during the assessment period, includes: S311: Determine the area of ​​the treated land and the weight of the untreated land based on the area of ​​the treated land and the area of ​​the untreated land, respectively.

[0062] Specifically, spatial distribution information of land use types within the small watershed is obtained from monitoring data, and the total area of ​​treated and untreated land within the small watershed is calculated using a Geographic Information System (GIS). Subsequently, the weights of these two area values ​​are determined.

[0063] In one possible implementation, the proportion of each type of land parcel's area to the total area of ​​the small watershed (i.e., the sum of the areas of treated and untreated parcels) is used as the weight of that type of land parcel. These two weights objectively reflect the importance of different types of land parcels in the overall spatial composition of the small watershed.

[0064] S312: Based on the weights, determine the weighted average of the soil organic carbon content of the treated plot and the soil organic carbon content of the untreated plot, and use it as the comprehensive organic carbon content.

[0065] The final result obtained by weighted averaging can represent the average carbon content level of the soil in the entire small watershed, that is, the comprehensive organic carbon content.

[0066] This application's embodiment calculates the comprehensive organic carbon content by weighted averaging the areas of treated and untreated plots. This fully considers the spatial proportion differences of different land use types within the small watershed, enabling the calculated comprehensive organic carbon content to more accurately reflect the average carbon content of eroded soils within the small watershed, thus improving the accuracy and reliability of subsequent ex-situ soil conservation and carbon sequestration calculations.

[0067] In one possible implementation, step S120, determining the in-situ soil carbon sequestration of the small watershed based on the monitoring data, includes: The in-situ soil carbon sequestration amount is obtained based on the soil organic carbon content of the treated plot during the assessment period, the area of ​​the small watershed, and the second difference between the soil erosion modulus of the baseline period and the soil erosion modulus of the assessment period.

[0068] The area of ​​a small watershed is the total catchment area of ​​the small watershed determined by tools such as Geographic Information System (GIS), and this area defines the spatial scope of this assessment.

[0069] The second difference quantifies the effectiveness of integrated small watershed management in suppressing soil erosion at its source. If the second difference is positive, the soil erosion intensity after management is significantly lower than before management.

[0070] By combining the soil organic carbon content of the treated plot during the assessment period, the area of ​​the small watershed, and the second difference, the amount of carbon fixed by the soil retained in place due to the reduction of the soil erosion modulus is obtained, i.e., the in-situ soil carbon sequestration amount.

[0071] This application embodiment reflects the erosion reduction effect of the treatment measures by using the difference between the soil erosion modulus of the baseline period and the evaluation period. It also converts the erosion reduction effect into the amount of carbon fixed by the soil retained in place due to the erosion reduction by using the soil organic carbon content and the area of ​​the small watershed. This makes the calculation logic of in-situ carbon fixation clear and the data traceable, thus improving the practicality and scientific nature of in-situ carbon fixation.

[0072] In one possible implementation, the in-situ soil carbon sequestration is obtained based on the soil organic carbon content of the treated area during the assessment period, the area of ​​the small watershed, and a second difference between the soil erosion modulus of the baseline period and the soil erosion modulus of the assessment period, including: The soil organic carbon content of the treated plot, the area of ​​the small watershed, and the second difference are multiplied together to obtain the in-situ soil carbon sequestration amount.

[0073] Specifically, the in-situ soil carbon sequestration capacity is determined using the following formula: C A =(M B -M E )·A·SOC M (4) In the formula, C A The amount of carbon sequestration in situ, expressed in tC. M B The soil erosion modulus of the small watershed during the baseline period is usually taken as the average value of the soil erosion modulus at various locations within the small watershed during the baseline period, expressed in t / km². 2 ·a; SOC M The average soil organic carbon content of the treated plots during the assessment period is %.

[0074] Among them, the soil erosion modulus M of the small watershed during the reference period B It can be obtained through field measurements, calculations using general soil loss equations, or dynamic monitoring data on soil and water loss from water conservancy departments.

[0075] Specifically, the second difference (M) B -M E The second difference (M) represents the reduction in soil erosion intensity per unit area. B -M E Multiplying the area A of the small watershed by the result is the total amount of soil erosion reduced annually across the entire small watershed due to the implementation of soil and water conservation measures, i.e. the soil quality successfully preserved in situ, thus quantifying the direct erosion reduction effect of the control measures.

[0076] Since the soil retained in situ is located on the remediation plot, the organic carbon content of the remediation plot represents the actual condition of this soil and is used as the basis for calculation. The mass of the soil retained in situ is multiplied by the organic carbon content of the soil in the remediation plot during the assessment period to convert the mass of the retained soil into the mass of organic carbon contained therein, i.e., in-situ soil carbon sequestration, which characterizes the amount of organic carbon directly fixed in situ by preventing soil erosion due to remediation measures.

[0077] The embodiments of this application clearly reveal the quantitative relationship between the three core elements of soil erosion reduction, scope of effect, and carbon content of the preserved soil. Through mathematical calculation models, the assessment of in-situ soil carbon sequestration is implemented from the conceptual level to the calculation execution level, so that the assessment results have clear physical meaning and reproducibility.

[0078] In one possible implementation, please combine Figure 2 and Figure 4 In step S130, determining the total soil and carbon sequestration of the small watershed based on the in-situ soil and carbon sequestration amount and the ex-situ soil and carbon sequestration amount includes: S1310: Determine the sum of the in-situ soil carbon fixation amount and the ex-situ soil carbon fixation amount.

[0079] Summing these two values ​​arithmetically yields a theoretical total carbon sequestration benefit that does not consider long-term risks. This sum represents the potential carbon sequestration benefits of soil and water conservation measures in terms of both erosion reduction and interception during the assessment period.

[0080] S1320: The sum is corrected using the risk factors of soil and water conservation measures to obtain the total amount of soil carbon sequestration.

[0081] Specifically, the formula for calculating the total amount of carbon sequestration in soil is as follows: C B = (C) A + C S )·(1 -P RISK (5) In the formula, C B The total amount of soil carbon sequestration in a small watershed is expressed in tC (tons of carbon). P RISK The risk factor is the non-permanent risk reduction rate of soil conservation function caused by factors such as damage to soil and water conservation measures in small watersheds.

[0082] A risk factor for soil and water conservation measures is one or a set of parameters used to quantify the probability of performance degradation or complete failure of a soil and water conservation project during its design life. Determining this risk factor can be a comprehensive process, calculated based on multi-source information stored in a database. For example, the risk factor can be related to the type of measure (e.g., engineering measures such as silt-retaining dams may have different failure modes and risk curves compared to vegetation measures); it can also be related to the age of the measure (aging engineering structures have a higher risk of failure); and it can also be related to the climate and geological conditions of the region (e.g., measures located in areas with heavy rainfall or frequent geological activity have a higher risk). This risk factor can be expressed as a value between 0 and 1 (e.g., 1%), with a higher value indicating a higher risk of measure failure or performance degradation.

[0083] By using this risk factor to correct the potential carbon sequestration benefits in both dimensions, the potential benefits that may not be realized due to potential risks are subtracted from the theoretical maximum benefits, thus obtaining a more robust and reliable assessment result in a statistical sense.

[0084] The embodiments of this application modify the theoretical carbon sequestration benefits through risk factors, so that the final evaluation result is no longer a static, idealized value, but a dynamic and prudent expected value that takes into account the long-term operational stability and actual uncertainties of soil and water conservation measures, which greatly enhances the scientificity and credibility of the evaluation results.

[0085] Based on the above, this application also provides a soil conservation and carbon sequestration capacity assessment system for small watersheds. The soil conservation and carbon sequestration capacity assessment system for small watersheds can be used in conjunction with the aforementioned method for assessing soil conservation and carbon sequestration capacity for small watersheds.

[0086] As an example, such as Figure 5 As shown, the soil and carbon sequestration capacity assessment system for small watersheds provided in this application includes: The monitoring data acquisition module 510 is used to acquire monitoring data of the small watershed during the baseline period before the implementation of soil and water conservation measures and the evaluation period after the implementation, wherein the baseline period and the evaluation period have the same duration. The first soil carbon sequestration determination module 520 is used to determine the in-situ and ex-situ soil carbon sequestration of the small watershed based on the monitoring data. The in-situ soil carbon sequestration represents the amount of carbon fixed by the soil retained in place due to the decrease in the soil erosion modulus. The ex-situ soil carbon sequestration represents the amount of carbon mineralization loss avoided by the soil that was eroded during the assessment period and intercepted in the small watershed due to the decrease in the sediment transport ratio. The second soil conservation and carbon sequestration determination module 530 is used to determine the total amount of soil conservation and carbon sequestration in the small watershed based on the in-situ soil conservation and carbon sequestration amount and the ex-situ soil conservation and carbon sequestration amount.

[0087] This application's embodiments quantify the carbon sequestration and erosion reduction benefits by using in-situ soil conservation carbon sequestration and quantify the carbon interception and sequestration benefits by using ex-situ soil conservation carbon sequestration. This overcomes the shortcomings of existing methods that cannot accurately calculate the carbon neutrality contribution of soil and water conservation in small watersheds due to limitations in the assessment scale. It also overcomes the problem of the assessment results being systematically too small, making the assessment results more scientific and complete, and able to more accurately reflect the actual contribution of soil and water conservation measures in small watersheds to carbon neutrality.

[0088] Figure 6 This is a schematic diagram of the structure of the electronic device provided in this application, such as... Figure 6As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630, and a communication bus 640, wherein the processor 610, the communication interface 620, and the memory 630 communicate with each other via the communication bus 640. The processor 610 can call logical instructions in the memory 630 to execute a method for assessing the soil conservation and carbon sequestration capacity of a small watershed, the method including: The monitoring data of the small watershed are obtained during the baseline period before the implementation of soil and water conservation measures and the evaluation period after the implementation, wherein the baseline period and the evaluation period are of the same length; Based on the monitoring data, the in-situ and ex-situ soil carbon sequestration amounts in the small watershed were determined. The total amount of soil and carbon sequestration in the small watershed is determined based on the in-situ soil and carbon sequestration amount and the ex-situ soil and carbon sequestration amount. The in-situ soil carbon sequestration capacity represents the amount of carbon fixed by the soil that is retained in place due to the decrease in the soil erosion modulus; the ex-situ soil carbon sequestration capacity represents the amount of carbon mineralization loss avoided by the soil that was eroded during the assessment period and intercepted in the small watershed due to the decrease in the sediment transport ratio.

[0089] Furthermore, the logical instructions in the aforementioned memory 630 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0090] On the other hand, this application also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions, and when the program instructions are executed by a computer, the computer is able to execute the method for assessing the soil conservation and carbon sequestration capacity of small watersheds provided in the above embodiments. The method includes: The monitoring data of the small watershed are obtained during the baseline period before the implementation of soil and water conservation measures and the evaluation period after the implementation, wherein the baseline period and the evaluation period are of the same length; Based on the monitoring data, the in-situ and ex-situ soil carbon sequestration amounts in the small watershed were determined. The total amount of soil and carbon sequestration in the small watershed is determined based on the in-situ soil and carbon sequestration amount and the ex-situ soil and carbon sequestration amount. The in-situ soil carbon sequestration capacity represents the amount of carbon fixed by the soil that is retained in place due to the decrease in the soil erosion modulus; the ex-situ soil carbon sequestration capacity represents the amount of carbon mineralization loss avoided by the soil that was eroded during the assessment period and intercepted in the small watershed due to the decrease in the sediment transport ratio.

[0091] In another aspect, this application also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, is implemented to perform the soil conservation and carbon sequestration capacity assessment method for small watersheds provided in the above embodiments, the method comprising: The monitoring data of the small watershed are obtained during the baseline period before the implementation of soil and water conservation measures and the evaluation period after the implementation, wherein the baseline period and the evaluation period are of the same length; Based on the monitoring data, the in-situ and ex-situ soil carbon sequestration amounts in the small watershed were determined. The total amount of soil and carbon sequestration in the small watershed is determined based on the in-situ soil and carbon sequestration amount and the ex-situ soil and carbon sequestration amount. The in-situ soil carbon sequestration capacity represents the amount of carbon fixed by the soil that is retained in place due to the decrease in the soil erosion modulus; the ex-situ soil carbon sequestration capacity represents the amount of carbon mineralization loss avoided by the soil that was eroded during the assessment period and intercepted in the small watershed due to the decrease in the sediment transport ratio.

[0092] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0093] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for assessing the soil conservation and carbon sequestration capacity of a small watershed, characterized in that, include: The monitoring data of the small watershed are obtained during the baseline period before the implementation of soil and water conservation measures and the evaluation period after the implementation, wherein the baseline period and the evaluation period are of the same length; Based on the monitoring data, the in-situ and ex-situ soil carbon sequestration amounts in the small watershed were determined. The total amount of soil and carbon sequestration in the small watershed is determined based on the in-situ soil and carbon sequestration amount and the ex-situ soil and carbon sequestration amount. The in-situ soil carbon sequestration capacity represents the amount of carbon fixed by the soil that is retained in place due to the decrease in the soil erosion modulus; the ex-situ soil carbon sequestration capacity represents the amount of carbon mineralization loss avoided by the soil that was eroded during the assessment period and intercepted in the small watershed due to the decrease in the sediment transport ratio.

2. The method for assessing the soil conservation and carbon sequestration capacity of a small watershed according to claim 1, characterized in that, The monitoring data includes the soil erosion modulus and sediment transport ratio of the small watershed corresponding to the baseline period and the assessment period; the small watershed includes untreated plots and treated plots, and the treated plots are plots where soil and water conservation measures are implemented during the assessment period; Accordingly, determining the ex-situ soil carbon sequestration amount of the small watershed based on the monitoring data includes: The comprehensive organic carbon content of the small watershed during the assessment period is determined based on the soil organic carbon content of the treated plots and the soil organic carbon content of the untreated plots during the assessment period. The ex-situ soil carbon sequestration amount is obtained based on the soil organic carbon mineralization ratio during the soil erosion process, the first difference between the sediment transport ratio during the baseline period and the sediment transport ratio during the assessment period, the area of ​​the small watershed, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content.

3. The method for assessing the soil conservation and carbon sequestration capacity of a small watershed according to claim 2, characterized in that, The determination of in-situ soil carbon sequestration in the small watershed based on the monitoring data includes: The in-situ soil carbon sequestration amount is obtained based on the soil organic carbon content of the treated plot during the assessment period, the area of ​​the small watershed, and the second difference between the soil erosion modulus of the baseline period and the soil erosion modulus of the assessment period.

4. The method for assessing the soil conservation and carbon sequestration capacity of a small watershed according to claim 1, characterized in that, The determination of the total soil and carbon sequestration amount of the small watershed based on the in-situ soil and carbon sequestration amount includes: Determine the sum of the in-situ soil-conserving carbon fixation amount and the ex-situ soil-conserving carbon fixation amount; The total amount of carbon sequestration in soil conservation is obtained by correcting the sum using the risk factors of soil and water conservation measures.

5. The method for assessing the soil conservation and carbon sequestration capacity of a small watershed according to claim 2, characterized in that, The method for obtaining the ex-situ soil carbon sequestration capacity based on the soil organic carbon mineralization ratio during soil erosion, the first difference between the sediment transport ratio during the baseline period and the sediment transport ratio during the assessment period, the area of ​​the small watershed, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content includes: The soil organic carbon mineralization ratio, the first difference, the area of ​​the small watershed, the soil erosion modulus during the assessment period, and the comprehensive organic carbon content are multiplied to obtain the ex-situ soil carbon sequestration amount.

6. The method for assessing the soil conservation and carbon sequestration capacity of a small watershed according to claim 3, characterized in that, The in-situ soil carbon sequestration is obtained based on the soil organic carbon content of the treated area during the assessment period, the area of ​​the small watershed, and the second difference between the soil erosion modulus of the baseline period and the soil erosion modulus of the assessment period, including: The average soil organic carbon content of the treated plot during the assessment period, the area of ​​the small watershed, and the second difference are multiplied to obtain the in-situ soil carbon sequestration amount.

7. The method for assessing the soil conservation and carbon sequestration capacity of a small watershed according to claim 2, characterized in that, The comprehensive organic carbon content of the small watershed during the assessment period is determined based on the soil organic carbon content of the treated plots and the untreated plots during the assessment period, including: The area of ​​the treated land and the weight of the untreated land are determined based on the area of ​​the treated land and the area of ​​the untreated land, respectively. The weighted average of the soil organic carbon content of the treated plot and the soil organic carbon content of the untreated plot is determined based on the weights, and is taken as the comprehensive organic carbon content.

8. A system for assessing the soil conservation and carbon sequestration capacity of a small watershed, characterized in that, include: The monitoring data acquisition module is used to acquire monitoring data of the small watershed during the baseline period before the implementation of soil and water conservation measures and the evaluation period after the implementation, wherein the baseline period and the evaluation period have the same duration; The first soil carbon sequestration determination module is used to determine the in-situ and ex-situ soil carbon sequestration of the small watershed based on the monitoring data. The in-situ soil carbon sequestration represents the amount of carbon fixed by the soil retained in place due to the decrease in the soil erosion modulus. The ex-situ soil carbon sequestration represents the amount of carbon mineralization loss avoided by the soil that was eroded during the assessment period and intercepted in the small watershed due to the decrease in the sediment transport ratio. The second soil conservation and carbon sequestration determination module is used to determine the total amount of soil conservation and carbon sequestration in the small watershed based on the in-situ soil conservation and carbon sequestration amount and the ex-situ soil conservation and carbon sequestration amount.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for assessing the soil conservation and carbon sequestration capacity of a small watershed as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium, wherein a computer program is stored on the non-transitory computer-readable storage medium, characterized in that, When the computer program is executed by the processor, it implements the method for assessing the soil conservation and carbon sequestration capacity of a small watershed as described in any one of claims 1 to 7.

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