Ground monitoring method for water and soil loss and carbon loss of road slope

Abstract

The invention discloses a ground monitoring method for water and soil loss and carbon loss of a road slope, and belongs to the field of ecological monitoring. The method comprises the following steps: setting an engineering disturbance area and a natural contrast area according to regional water and soil loss, vegetation coverage and altitude gradient, and arranging an erosion pile sample plot to form a contrast observation network; removing impurities on the surface layer of the sample plot, collecting a soil sample, obtaining volume-weight data, and recording environmental parameters such as geographic position, altitude and gradient; the method comprises the following steps: pretreating a soil sample, measuring organic carbon content and volume weight, and obtaining carbon components and physical parameters; the exposed height of the erosion pile is measured regularly, erosion / accumulation modulus is calculated, and a space-time database is established in combination with weather, disturbance events and the like; and based on the erosion / accumulation data and the physical and chemical parameters, constructing a model to quantify carbon loss and carbon sequestration caused by water and soil loss. According to the method, through contrast point distribution, high-frequency observation and multi-parameter analysis, whole-process dynamic monitoring of complex terrain carbon migration is achieved, and the method is suitable for accurate evaluation of water and soil loss induced carbon loss in the field of ecological monitoring.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ecological monitoring, in particular to a ground monitoring method for carbon loss caused by water and soil loss of road slope. BACKGROUND

[0002] Water and soil loss, as a global ecological and environmental problem, refers to the geological process of soil and its parent material erosion, transportation and re-deposition under the combined action of natural factors (such as gravity, water flow, wind force) and human activities. This phenomenon is particularly prominent in mountainous and hilly areas with significant topographic relief, concentrated rainfall, and complex terrain with low vegetation coverage, not only leading to land degradation and decline in agricultural productivity, but also easily inducing disasters such as mountain torrents and mudslides, posing a direct threat to ecological safety and sustainable development of human society. As a core indicator of terrestrial ecosystem change, water and soil loss is closely related to topography, climate conditions and land use patterns, and its dynamic process deeply affects the evolution of landform, the maintenance of ecological balance and the optimization of land resources, and has irreplaceable scientific value in the assessment of ecological services.

[0003] With the intensification of global climate change and the promotion of the "double carbon" target, the dynamic balance of soil carbon pool, as the largest organic carbon storage carrier of terrestrial ecosystem, has attracted increasing attention on its impact on carbon cycle. For a long time, the role of water and soil loss on soil carbon storage and carbon cycle process has been underestimated, and the loss and spatial redistribution of organic carbon caused by surface soil erosion directly changes the structure of regional carbon pool, and further affects the carbon sink capacity of terrestrial ecosystem. Therefore, precise monitoring of carbon loss during water and soil loss is not only the basis for soil resource protection, ecological restoration and sustainable agricultural development, but also the key link connecting "soil-ecology-climate-agriculture", and its technical role runs through the whole chain from basic scientific cognition to application practice, providing an integrated solution of "measurement-evaluation-control" for solving the coordination problem of ecological protection and sustainable development.

[0004] Currently, the monitoring technology research on water and soil loss and the induced carbon loss mainly focuses on soil erosion modulus calculation, carbon storage determination and carbon cycle model construction, etc.

[0005] Although traditional monitoring methods (such as erosion gully measurement and soil sampling analysis) provide data support for basic research, they have significant technical bottlenecks. On the one hand, there is a lack of continuous dynamic monitoring capability at the regional scale, making it difficult to reveal the spatial heterogeneity of soil carbon loss at multiple spatiotemporal scales. Because: traditional methods (such as erosion gully measurement and soil sampling) rely on manual point observation, the number of sampling points is limited and the spatial distribution is discrete, making it difficult to cover micro-geomorphic units (such as steep slopes, valleys, and accumulation fans) in complex terrain, resulting in time series data gaps and the inability to capture the carbon loss mutation process triggered by short-duration strong erosion events such as heavy rain and snowmelt. In addition, the distribution of soil carbon itself has high spatial heterogeneity (affected by soil parent material, vegetation type, human activity, etc.), and traditional sampling methods are based on the assumption of "homogenization", using limited sample points to estimate the overall situation of the region, which may mask local carbon loss hotspots (such as concentrated erosion in engineering disturbance areas) due to sample bias. For example, in mountainous areas, the carbon loss rate of different slope directions and slopes may differ by several times, but traditional methods are difficult to quantify such micro-differences. In addition, traditional methods focus on physical measurement of soil erosion modulus (such as sediment volume), and the monitoring of carbon loss is only indirectly calculated through "post-determination" of soil organic carbon content, lacking dynamic tracking of carbon form transformation (such as the differentiation of particulate carbon and dissolved carbon) in the process of erosion-transportation-deposition. This "heavy physics, light chemistry" monitoring mode makes it impossible to reveal the migration and transformation rules of carbon loss in different geomorphic units (such as erosion area, transition area, and deposition area). On the other hand, these traditional methods pay too much attention to physical erosion processes and lack sufficient analysis of the coupling mechanism between soil erosion and soil carbon migration and transformation.

[0006] In recent years, although the development of remote sensing (RS), geographic information system (GIS) and numerical simulation technology has improved the regional monitoring capability, the emerging model simulation and data assimilation method provides theoretical support for large-scale carbon flux estimation. However, in complex terrain conditions such as mountainous areas and engineering disturbed areas, there are still problems such as insufficient monitoring accuracy, low spatio-temporal resolution and lack of ground verification data, and a systematic and efficient soil erosion carbon loss monitoring technology system has not yet been formed. This mainly reflects that: the remote sensing technology is limited, the mountainous terrain shadow, cloud and fog and the vegetation sheltering lead to spectral distortion and data blank; the contradiction between the traditional remote sensing resolution and coverage range is difficult to capture small-scale variation. The model simulation defects, the complex terrain parameter spatial heterogeneity is high, and the traditional sampling is difficult to obtain accurately; the model simplifies the micro-topography and the chemical mechanism of carbon migration, and the dynamic boundary of the engineering disturbed area breaks the fixed assumption, and the error is significant. The ground monitoring is limited, the discrete point data is difficult to represent the regional law, the high-frequency observation cost is high, the implementation is difficult, and the traditional sampling is easy to damage the ecology. The data fusion bottleneck, the spatio-temporal scale of remote sensing and ground data is not matched, the heterogeneous cooperation is poor, and real-time dynamic calibration is lacking, which affects the modeling accuracy. The mechanism cognition blank, the nonlinear characteristics of carbon loss (coupled with the particle size of sediment) and the spatial redistribution process are ignored, and there is a lack of unified monitoring specification, and the regional evaluation lacks scientific benchmarks.

[0007] In other words, for the ground monitoring technology of road slope soil erosion carbon loss, remote sensing and GIS technology has multiple bottlenecks: the pixel scale of medium and low resolution remote sensing (such as Landsat) is large (30 meters to kilometer level), which is difficult to capture small-scale carbon loss characteristics; high-resolution remote sensing (such as unmanned aerial vehicle) has insufficient coverage and high cost, and cloud cover and vegetation cover lead to discontinuous data in mountainous areas. Related models (such as RUSLE, InVEST) rely on terrain, vegetation and other parameters, which have significant errors in complex terrain, ignore the vertical differentiation of soil organic carbon, and the prediction ability of human disturbance area decreases. The multi-source data fusion has the problems of non-uniform spatio-temporal benchmark and scale mismatch, and there is no universal method for heterogeneous data registration and weight distribution, so the reliability of the fusion result is low.

[0008] In view of the lack of existing technology for accurate monitoring of carbon loss induced by soil erosion in complex geographical environment such as road slope, it is urgent to develop a monitoring method with high precision, high spatio-temporal resolution and regional representativeness to meet the technical needs of dynamic monitoring of soil carbon pool. SUMMARY

[0009] In order to alleviate or partially alleviate the above technical problems, the solution of the present application is as follows:

[0010] A ground monitoring method for road slope soil erosion carbon loss, comprising the following steps:

[0011] Step S1: Preselect observation points according to regional soil erosion distribution, vegetation coverage and altitude gradient, wherein the gradient division basis is 100-meter altitude difference for regions with mountain altitude greater than 500 meters and 50-meter altitude difference for regions with mountain altitude less than 500 meters, and an engineering disturbance area and a natural control area are set at each altitude gradient, the slope difference between the two is ≤±2°, and the aspect difference is ≤±10°, the engineering disturbance area is a stable slope with excavation duration ≥1 year; the size of each monitoring plot in the engineering disturbance area and the natural control area is 5m x 20m, and a plurality of erosion stakes are arranged at an interval of every 2.5m in the width direction and every 4m in the length direction;

[0012] Step S2: After removing the surface vegetation, litter and rocks in the monitoring plot, 0-20cm soil layer samples with a total amount of ≥500g are collected by uniformly arranging points in the plot, and soil samples are simultaneously collected by the cutting ring method for bulk density determination; the environmental parameters such as geographic location, altitude, slope, aspect and vegetation coverage of the plot are recorded; the five-point waffle or chessboard point arrangement method is used for the collection of the soil samples to avoid the root dense area to ensure the representativeness of the samples; the cutting ring sample needs to be vertically pressed into the soil, and after the excess soil body is cut off, it is sealed and stored for analysis and detection within 24 hours;

[0013] Step S3: After the collected soil samples are naturally dried, plant roots and gravel with particle size >2mm are removed, and after fine grinding through a 0.15mm sieve, the samples are divided for determination of the soil organic carbon content of each quarter; the cutting ring method is used to determine the soil bulk density, and the potassium dichromate oxidation-external heating method is used to determine the soil organic carbon content;

[0014] Step S4: Within the continuous observation period, the newly exposed height of all erosion stakes is measured every quarter, and the erosion / deposition modulus is calculated, and the observation date, weather and potential impact events are recorded simultaneously to establish a spatio-temporal database of the erosion process;

[0015] Step S5: Calculate the carbon loss based on the physical parameters.

[0016] Further, in step S1, it further includes: marking the erosion stake number, recording the initial exposed height and the initial condition of the soil, the observation period is every 3 months, and the weather and potential impact events are recorded simultaneously.

[0017] Further, in step S3, the cutting ring method is used to determine the soil bulk density, which specifically includes: weighing the empty cutting ring and the cutting ring with wet soil, after being saturated with water and dried and balanced, it is dried to constant weight, and the parameters such as soil moisture content, volume moisture content, bulk density and porosity are calculated.

[0018] Further, the soil organic carbon content is determined by potassium dichromate oxidation-external heating method in step S3, which specifically includes: weighing the sieved and air-dried soil sample, sequentially adding potassium dichromate solution, concentrated sulfuric acid and silver sulfate, boiling in an oil bath at 170-180℃ for 5 min, after cooling, using o-phenanthroline as an indicator, titrating with ferrous sulfate until the brown red end point, and calculating the organic carbon content according to the titration volume.

[0019] Further, in step S5, the physical parameters include: observed plot area, cumulative erosion or deposition depth, soil bulk density, soil organic carbon content, soil sampling depth, and organic carbon oxidation coefficient.

[0020] Further, the soil organic carbon content is equal to

[0021] wherein SOC1 is the soil organic carbon content in the first quarter, SOC2 is the soil organic carbon content in the second quarter, the second quarter is the next quarter of the first quarter, H is the soil sampling depth, H is the cumulative erosion or deposition depth.

[0022] Further, the carbon loss is calculated based on the physical parameters in step S5, specifically:

[0023] Slope carbon loss amount suitable for erosion area ;

[0024] Slope carbon loss oxidation amount ;

[0025] Slope carbon sequestration amount suitable for deposition area or natural control area ;

[0026] Slope carbon sequestration oxidation amount ;

[0027] Carbon loss caused by water and soil loss on the same elevation slope ;

[0028] wherein A is the observed plot area, BD is the soil bulk density, SOC is the soil organic carbon content, and H is the soil sampling depth, H is the cumulative erosion or deposition depth, P se is the organic carbon oxidation coefficient.

[0029] Further, the step S1 further includes:

[0030] For regular observation, the steel rod exposure height is measured every 3 months, clear and sunny weather is selected, the steel ruler is used to measure the vertical distance from the ground surface to the top end of the steel rod, and the average value is obtained by repeating the measurement 3 times;

[0031] For the encrypted observation, within 48 hours after the rainstorm with daily rainfall of 50mm or more and the strong erosion event of snowmelt, temporary observation is increased to record the abnormal erosion amount, wherein,

[0032] The erosion stake is the steel drill.

[0033] Further, in the step S4, the environmental factors recorded synchronously every quarter further include: observation date, weather conditions including temperature, humidity and rainfall intensity, potential impact events including construction, grazing and pest and disease, and appearance inspection of the steel drill including whether to be inclined, displaced or damaged.

[0034] Further, the soil bulk density is the arithmetic mean of the soil bulk density of the first quarter and the soil bulk density of the second quarter.

[0035] The present application has the following innovative breakthroughs: (a) A high-density spatio-temporal sampling network is used to arrange erosion stake fixed plots based on altitude gradient (100m in high mountain area and 50m in low mountain area) and disturbance type, to cover the spatial scale of "point-line-surface", to capture the surface erosion / accumulation change and carbon content dynamics with high precision, and to solve the problem of insufficient representativeness of traditional point data. (b) A multi-source data coupling analysis technology is used to integrate the erosion physical process (erosion modulus and topographic parameter) and the carbon chemical process (organic carbon component and soil bulk density), to construct a "process-mechanism" coupling model through a time series weighting formula and a partitioned quantitative method, to quantify the carbon loss-deposition balance of different geomorphic units, and to break through the limitation of traditional models on a single physical process. (c) A scale expansion and dynamic calibration system is combined with a quarterly observation frequency to realize the expansion of carbon loss evaluation from plot scale to regional scale, to solve the problem of "point difficult to expand to surface", and to integrate the latest observation data in real time to dynamically calibrate the model parameters, and to improve the monitoring accuracy and timeliness under complex terrain.

[0036] The technical scheme of the present application has one or more of the following beneficial technical effects:

[0037] (1) It has precise dynamic monitoring and quantification capability. Through high-frequency ground plot observation (quarterly period) and erosion stake grid arrangement (5m*20m), the limitation of low spatio-temporal resolution of traditional remote sensing / GIS is broken through, the ultra-high precision tracking of carbon loss in complex terrain (roadside slope and engineering disturbance area) is realized, and the monitoring problem in high variability area is solved.

[0038] (2) It improves the monitoring efficiency and ecological friendliness. Gradient control points (altitude gradient + disturbance / natural control area) are used to reduce more than 30% of invalid monitoring investment and reduce field work; standardized operation process easy to popularize and apply avoids secondary disturbance to ecological environment caused by large-area sampling, and is suitable for long-term monitoring in ecologically sensitive areas.

[0039] (3) High practical value and easy to promote. The "point-line-surface" integrated monitoring network is constructed, and high-precision spatio-temporal dynamic data are output, which provides core technical support for ecological restoration effectiveness evaluation, regional "double carbon" target accounting and land use optimization. The standardized process of the application can be directly applied to complex topography such as highland mountainous area and typical river basin.

[0040] (4) The continuous monitoring of ground erosion pile and high-frequency soil physical and chemical analysis are innovatively combined, which breaks through the spatio-temporal limitations of traditional single physical measurement or low-frequency sampling, and realizes the whole process and high-resolution dynamic quantification of road slope soil and water loss and induced carbon loss.

[0041] In summary, the application realizes "continuous dynamic monitoring" and "multi-scale heterogeneity analysis" by "ground measured high-precision data anchoring + model simulation spatio-temporal extension", and provides key technical support for soil carbon stock evaluation, ecological restoration and "double carbon" target landing.

[0042] In addition, other beneficial effects of the application will be mentioned in the specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a flow chart of the ground monitoring method of road slope soil and water loss carbon loss of the application;

[0044] Figure 2 is a soil bulk density change graph of different sample plots at different periods;

[0045] Figure 3 is a soil organic carbon content change graph of different sample plots at different periods;

[0046] Figure 4 is a soil erosion depth change graph of different sample plots at different periods;

[0047] Figure 5 is a slope SOC accumulation and loss comparison graph of different sample plots;

[0048] Figure 6 is a slope soil and water loss sample plot carbon loss comparison graph. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the application clearer, the technical scheme in the application will be described clearly and completely below in combination with the drawings in the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0050] In order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the terms "first", "second", etc. are used to distinguish the same or similar items with basically the same functions and effects. Those skilled in the art can understand that the terms "first", "second", etc. do not limit the quantity and execution order.

[0051] Figure 1 is a flow chart of the ground monitoring method for carbon loss of road slope soil erosion according to the present application. As an exemplary embodiment of the present application, the ground monitoring method for carbon loss of road slope soil erosion according to the present application comprises the following steps:

[0052] Step S1: Pre-select observation points according to regional soil erosion distribution, vegetation coverage and altitude gradient, wherein the altitude gradient is divided by 100 meters of altitude difference for mountainous areas with an altitude of more than 500 meters, and by 50 meters of altitude difference for mountainous areas with an altitude of less than 500 meters, and engineering disturbance areas and natural control areas are set at each altitude gradient, with a slope difference of ≤±2° and a slope direction difference of ≤±10°, the engineering disturbance area is a stable slope with an excavation duration of ≥1 year; the size of each monitoring plot in the engineering disturbance area and the natural control area is not greater than 5m x 20m, and a plurality of erosion stakes are arranged at an interval of every 2.5m in the width direction and every 4m in the length direction; the erosion stakes are marked with numbers, the initial exposed height and the initial soil condition are recorded, the observation period is every 3 months, and the weather and potential impact events are recorded synchronously.

[0053] Specifically, before the field monitoring is implemented, the remote sensing preprocessing (such as Landsat image interpretation) is combined with the site reconnaissance, the regional soil erosion intensity classification (based on the USLE model), the vegetation coverage (NDVI inversion) and the altitude distribution characteristics are comprehensively analyzed, and the soil erosion active area is circled as a candidate monitoring area. For example, for a mountain with an overall altitude of ≥500 meters, the altitude gradient is divided by 100 meters of altitude difference; for a low mountain and hilly area with an altitude of <500 meters, the altitude gradient is divided by 50 meters of altitude difference, so as to ensure that each gradient contains typical micro-landform units (such as steep slopes, gentle slopes and valleys).

[0054] In each altitude gradient, an engineering disturbance area and a natural control area are set: the engineering disturbance area: select areas with significant human disturbance such as road slopes and mine spoil sites, requiring a slope excavation duration of ≥1 year (to ensure stable erosion process), a slope range of 20°~45°, and a slope direction mainly being a sunny slope (south slope) or a shady slope (north slope) to avoid the interference of light difference caused by mixed sunny and shady slopes on the monitoring results. The natural control area: in the same altitude gradient, select natural slopes with a straight-line distance of ≤500 meters from the engineering disturbance area, ensure that the slope is within an error range of ±2° and the slope direction is within an error range of ±10°, the vegetation type is mainly original herbaceous / shrub, and recent human disturbance (such as reclamation and deforestation) is excluded.

[0055] Then set the sample plot grid and erosion stake layout. For sample plot specifications, each monitoring sample plot is 5 meters (slope width) x 20 meters (slope length) in size, and the boundaries are marked along the contour line, which can be marked with a GPS positioning instrument (accuracy ≤ 1 meter) to mark the coordinates of the four corners. For the erosion stake array, a 1.2 cm diameter, 50 cm long stainless steel drill (surface rust treatment) is evenly laid out with a horizontal spacing of 2.5 meters and a vertical spacing of 4 meters, a total of 18. The drill is perpendicular to the slope normal direction and is punched into the soil layer to ensure that the top is flush with the ground, and the verticality is calibrated using a level (deviation ≤ 1°).

[0056] Further, the top of the drill is sprayed with fluorescent red paint, numbered by row (A~E) and column (1~5) (such as A1, B3), and a special record form is used to record in detail:

[0057] (1) Stake coordinates (longitude, latitude, and elevation);

[0058] (2) Depth of soil penetration (ensure that the drill penetrates the soil by ≥30 cm);

[0059] (3) Surface soil type (such as sandy loam, clay loam);

[0060] (4) Installation date and on-site photos (including panoramic and close-up, resolution ≥300DPI).

[0061] In addition, long-term monitoring safeguards can also be set up, for example, which can include a warning system: a 1.2-meter-high rust-resistant metal fence is set up at the boundary of the sample plot, and a reflective warning post is installed every 5 meters, marked with the words "ecological monitoring area, do not destroy", to prevent human interference.

[0062] The present application also sets up a dynamic observation cycle, mainly divided into regular observation and intensive observation. For regular observation, the exposed height of the drill is measured every 3 months (quarterly), and clear and sunny weather is selected, and a steel ruler (accuracy 1 mm) is used to measure the vertical distance from the ground surface to the top of the drill, and the measurement is repeated 3 times to take the average value. For intensive observation, within 48 hours after heavy rain (daily rainfall ≥50 mm), snowmelt and other strong erosion events, temporary observation is increased, and abnormal erosion is recorded.

[0063] In addition, the present application also synchronously records environmental factors, that is, the "on-site record form" needs to be filled in each time of observation, for example, the content can include: observation date, weather conditions (temperature, humidity, rainfall intensity); potential impact events (such as construction, grazing, pest and disease); drill appearance inspection (whether inclined, displaced, damaged).

[0064] After the first installation is completed, the initial terrain point cloud data of the sample plot is obtained by three-dimensional laser scanning (accuracy ± 2mm), a digital surface model (DSM) is established, and it is used as the basis for subsequent erosion / deposition calculation. At the same time, the soil profile data (0~50cm) of the center position of the sample plot is collected, the mechanical composition (sieve analysis method) and pH value are measured, and it is used for later model parameter calibration.

[0065] The present application designs by altitude gradient-disturbance type two-dimensional control, combines high-density grid distribution points and multi-source reference data (terrain, soil, weather), and constructs a traceable and repeatable erosion monitoring system, which provides basic support for spatial and temporal differentiation analysis of carbon loss.

[0066] Step S2: After removing the surface vegetation, litter and rocks in the monitoring sample plot, 0~20cm soil layer, total weight ≥500g of loose soil samples are collected in the sample plot, and soil samples are collected by the cutting ring method for bulk density determination; The environmental parameters such as geographical position, altitude, slope, slope direction and vegetation coverage of the sample plot are recorded; The five-point waffle or chessboard distribution method is used for loose soil sample collection to avoid root dense areas to ensure sample representativeness; The cutting ring sample needs to be vertically pressed into the soil, and after cutting off the excess soil, it is sealed and stored, and the analysis and detection are completed within 24 hours.

[0067] Specifically, first of all, the ground needs to be pretreated and the sampling area needs to be planned. Before formal sampling, use a stainless steel rake to gently remove the surface vegetation, litter and rocks with a particle size of >5cm in the sample plot, and avoid using iron tools to damage the soil structure. For steep slope sample plots with a slope of >25°, use rope fixation + ladder type operation to ensure safety. The removal range needs to cover the entire 5m×20m sample plot, exposing the fresh soil surface, while retaining the surface microtopography (such as small soil mounds, shallow gullies) to maintain the original erosion conditions.

[0068] Secondly, the soil sample collection technology is standardized. For loose soil sample collection, the main design is the distribution method, sampling depth and special area treatment. Regarding the distribution method, the five-point waffle sampling method (suitable for flat terrain areas) or the chessboard sampling method (suitable for broken terrain areas) is used, and 5~9 sampling points are evenly distributed in the sample plot, with a distance of ≥2m between each point. Regarding the sampling depth, a stainless steel soil drill is used to vertically drill into the soil, and 0~20cm soil layer samples are collected, about 100g of soil sample is collected at each point, and after mixing, roots, insects and stones with a particle size of >2mm are removed, and then they are packed into polyethylene sealed bags with unique labels, with a total weight of ≥500g. Regarding the special area treatment, 1~2 additional sampling points are added in the slope cracks and accumulation fans of the engineering disturbance area, and they are separately marked as "disturbance encryption samples".

[0069] For the collection of cutting ring samples, a stainless steel cutting ring with a volume of 100 cm³ can be used, which is sterilized in advance with alcohol. A flat area without root system distribution is selected, and the cutting ring is pressed vertically into the soil until it is fully embedded. The excess soil at both ends of the cutting ring is cut off to ensure that it is flush with the cutting ring. The cutting ring is sealed at both ends with plastic wrap after weighing, and then placed in a thermos box (4°C) containing ice bags. The laboratory measurements should be completed within 24 hours.

[0070] Regarding the accurate measurement of environmental parameters, the geographical location, altitude and slope, slope direction, and vegetation parameters are involved. Specifically, the coordinates (latitude and longitude) of the sample plot center can be measured using a Trimble GPS receiver (accuracy ± 2 cm) to six decimal places.

[0071] For example, the altitude can be measured by the built-in barometric altimeter of the GPS (error ± 1 m), and the slope can be measured at three representative locations in the sample plot using an electronic slope meter (accuracy ± 0.1°), and the average value is taken.

[0072] For example, the main slope direction can be measured using a compass (accuracy ± 5°), and the vegetation coverage of the sample plot can be recorded simultaneously (estimated using the grid method with a grid size of 1 m x 1 m), the dominant species name and height.

[0073] Further, to control the quality of sampling, parallel samples can be set, and field records can be made.

[0074] Specifically, one parallel sample (repeated sampling) can be set for every 10 sample plots for precision verification of laboratory analysis, and the relative deviation of the parallel sample should be less than 10%.

[0075] When recording in the field, waterproof paper records or mobile terminal APPs can be used to record the following example information in real time: sample plot number, sampling date, and sampler's signature; soil color (described by Munsell color card), texture (initially judged by hand); abnormal conditions (such as soil compactness, odor, and pollution marks).

[0076] During transportation and storage, the sample bags and cutting rings should be placed in shockproof foam boxes to avoid soil layering caused by violent shaking. The temperature should be maintained at ≤25°C and the humidity should be maintained at ≤60% during transportation.

[0077] Finally, a three-in-one traceability system for sample location and environmental parameters is established. A label containing a QR code is attached to the sample bag, and scanning the code can jump to the database to view the GPS point, sampling time, and environmental parameters of the sample. A video of the sampling site is also taken simultaneously (resolution ≥1080P) to record the sampling sequence and point distribution as original data for archiving.

[0078] The application ensures the representativeness, accuracy and traceability of collected data by standardizing a sampling process, synchronously measuring multiple parameters and controlling the whole chain quality, and provides reliable basic input parameters for subsequent carbon loss models.

[0079] Step S3: After the collected soil sample is naturally dried, plant roots and gravel with a particle size greater than 2 mm are removed, the soil sample is finely ground through a 0.15 mm sieve, and the soil sample is sampled for determination of the soil organic carbon content in each quarter; the soil bulk density is determined by the cutting ring method, specifically including: the mass of the empty cutting ring and the cutting ring with wet soil is weighed, the cutting ring is soaked with water to saturation, dried and balanced, and then baked to constant weight, and the soil mass water content, volume water content, bulk density and porosity are calculated; the soil organic carbon content is determined by the potassium dichromate oxidation-external heating method: the sieved and dried soil sample is weighed, potassium dichromate solution, concentrated sulfuric acid and silver sulfate are added in turn, and boiled in an oil bath at 170-180°C for 5 minutes, then cooled, and titrated with ferrous sulfate as an indicator until the end point of brown red, and the organic carbon content is calculated according to the titration volume.

[0080] Specifically, first, the soil sample is pretreated, including: the collected loose soil sample is placed in a ventilated cool place and naturally dried (temperature ≤ 30°C, avoiding direct sunlight), and the drying time is usually 3-7 days, until the soil particles are completely loose and easy to break. Then, the plant roots (length > 1 cm), insect bodies and gravel with a particle size greater than 2 mm are picked out one by one using a stainless steel tweezers, ensuring that the soil sample purity is greater than 95%. Finally, the dried soil sample is placed in an agate mortar and gently ground with a wooden pestle until there are no obvious lumps, and the soil sample is sieved through a 0.15 mm aperture nylon sieve (corresponding to 100 mesh), the sieved soil sample is loaded into a ground glass bottle, and the label "sieved sample" is attached. The residual soil sample is saved separately and labeled as "coarse particles".

[0081] Then, the soil bulk density is determined, preferably by the cutting ring method. For example, the instruments used include: a stainless steel cutting ring (volume 100 cm³), an electronic balance (accuracy 0.01 g), a flat-bottomed basin, an oven (temperature control accuracy ±1°C), and a desiccator.

[0082] After the mass of the empty cutting ring (m1, g) is weighed, the cutting ring is vertically pressed into the soil at the sampling point (avoiding the roots), the cutting ring is completely inserted into the soil, the cutting ring with soil is dug out, the excess soil at both ends of the cutting ring is cut off with a soil cutting knife, and the soil sample is leveled with the cutting ring, and the mass of the cutting ring with wet soil (m2, g) is weighed.

[0083] The bottom cover of the cutting ring is removed, the filter paper bottom cover with mesh is retained, the cutting ring is placed in a flat-bottomed basin, distilled water is poured into the cutting ring to the upper edge, the soil is soaked for 12 hours to fully saturate with water, the outer wall is wiped dry after being taken out, and the mass of the saturated wet soil (m3, g) is weighed.

[0084] Remove the bottom cover, place the ring knife in a flat dish with dry sand, dry at room temperature (20±2℃) for 2 hours, and weigh the dry mass (m4, g).

[0085] Put the ring knife into the oven and dry at 105±2℃ until constant weight (usually 12-24 hours), then take it out and place it in a desiccator to cool for 30 minutes, and weigh the dried soil mass (m5, g).

[0086] Then, calculate the following parameters: soil bulk density (ρb, g / cm³): ρb=m5 / 100; mass water content (θm, %): θm=[(m2-m5) / m5]×100; volume water content (θv, %): θv=θm×ρb; porosity (n, %): n=(1-ρb / ρs)×100 (ρs takes 2.65 g / cm³, which is the default value of soil particle density).

[0087] Then, determine the soil organic carbon (SOC) content, preferably by potassium dichromate oxidation plus heating method.

[0088] The reagents used here mainly include: 0.8000 mol / L potassium dichromate solution: weigh 39.224 g K2Cr2O7 and dissolve in distilled water, make up to 1000 mL; concentrated sulfuric acid (H2SO4, analytical pure, density 1.84 g / mL), which needs to be cooled to room temperature in advance; o-phenanthroline indicator: weigh 1.485 g o-phenanthroline and 0.695 g FeSO4·7H2O and dissolve in 100 mL distilled water, the solution is brown red.

[0089] As for the operation steps, they include: a). Weighing: 0.2-0.5 g of air-dried soil sample (0.15 mm sieve) is weighed (to 0.0001 g) by the reduction method and placed in a 250 mL hard glass test tube. 0.1 g of silver sulfate powder (catalyze chloride ions) is added. b). Liquid oxidation: 5.00 mL of 0.8000 mol / L potassium dichromate solution is accurately added with a pipette, and 5.00 mL of concentrated sulfuric acid is slowly injected (along the wall of the test tube to avoid violent reaction). Immediately shake the soil sample to disperse it, and the solution should be orange yellow or orange red (if it is green, it indicates that the soil sample has too high organic matter content, and the sample weight needs to be reduced for retesting). c). Oil bath heating: the test tube is placed in a preheated oil bath at 185-190℃, ensuring that the liquid surface of the test tube is lower than the oil surface, and the solution is maintained at boiling for 5 minutes (the timing starts from the boiling of the solution in the test tube). During this period, the test tube is gently shaken to ensure uniform reaction, and the temperature in the oil bath should be controlled at 170-180℃. d). Cooling titration: the test tube is removed and cooled to room temperature, and the solution is transferred to a 250 mL conical flask. The inner wall of the test tube is rinsed with distilled water for 3 times, and the total volume in the conical flask is about 80 mL. 3-4 drops of phenanthroline indicator are added, and the solution is titrated with 0.2 mol / L ferrous sulfate solution. The color of the solution changes from orange yellow to blue green to brown red, which is the end point. The titration volume (V, mL) is recorded.

[0090] In addition, a blank experiment step can also be selected: the same amount of calcined soil (to eliminate organic matter) is operated according to the above steps, and the blank titration volume (V0, mL) is recorded.

[0091] The soil organic carbon content (g / kg) can be calculated according to the following formula: [(V0-V) x 0.8000 x 0.003 x 1.724 x 1.1] / sample weight (g). The correction coefficient: 1.724 is the conversion coefficient of soil organic carbon to organic matter, and 1.1 is the oxidation correction coefficient (assuming the oxidation rate of potassium dichromate is 90%).

[0092] Finally, as for the quality control and data recording, 10% of the samples in each batch are set as parallel samples, and the relative deviation should be less than 5%, otherwise the samples need to be retested.

[0093] At the same time, the sample number, sample weight, titration volume, blank value, analysis date and operator are also recorded, and the titration process image data (such as the color photo of the titration end point) is saved.

[0094] It is worth mentioning that the concentrated sulfuric acid operation should be carried out in a fume hood with anti-corrosion gloves; when the oil bath is heated, open flames should be avoided to prevent the oil bath medium from splashing out.

[0095] The application ensures the accuracy of soil physical properties and carbon component data by standardizing the pretreatment process, calibrating precision instruments and a double-parallel quality control system, provides key input parameters for carbon loss models, and improves the measurement accuracy of high-organic-matter soil through a silver sulfate catalysis and oxidation correction mechanism.

[0096] Step S4: During the continuous observation period, the newly exposed height of all erosion stakes is measured every quarter, and the erosion / deposition modulus is calculated, and the observation date, weather and potential impact events are recorded simultaneously to establish a spatio-temporal database of the erosion process.

[0097] Specifically, during the continuous observation period (≥1 year, every quarter), the newly exposed height of 18 erosion stakes is measured using a steel ruler (accuracy ±1 mm), and each measurement is repeated three times to obtain the average value.

[0098] Further, the average erosion / deposition thickness and the erosion / deposition modulus, which can dynamically reflect the spatio-temporal variation characteristics of slope soil erosion process, are calculated.

[0099] The erosion modulus (Soil Erosion Modulus, SEM) refers to the amount of soil erosion or deposition per unit area per unit time, and is a core indicator for measuring the intensity of soil erosion on the ground surface, with a unit of t / (hm 2 ·a) (tons per hectare per year), which physically means the amount of soil mass change per hectare of land within a year due to erosion (or deposition).

[0100] In the present application, the erosion / deposition modulus = (average erosion / deposition thickness × soil bulk density × 10 4 ) / observation period, wherein the unit of the observation period is years.

[0101] In addition, the observation date, weather and potential impact events (such as heavy rain, engineering disturbance) are recorded simultaneously to establish a spatio-temporal database of the erosion process, which dynamically reflects the seasonal variation characteristics of slope soil erosion.

[0102] Step S5: Calculate carbon loss based on physical parameters.

[0103] The slope erodes or deposits with natural and engineering disturbances, and the surface soil is eroded and taken away, i.e. carbon loss (lost carbon), or material deposition leads to short-term carbon sequestration (deposited carbon). The former is a carbon source and the latter is a carbon sink, and both are quantified in the present application.

[0104] To realize the quantitative evaluation of carbon flux on slope scale, the present application proposes the following carbon loss model based on the calculation of physical parameters. The model comprehensively considers five core variables of slope area (observation plot area), soil erosion thickness (cumulative erosion or deposition depth), soil bulk density, soil organic carbon content and oxidation conversion coefficient (organic carbon oxidation coefficient), to realize the quantitative calculation of carbon loss and carbon sequestration in a simple and measurable manner. Specifically, it involves:

[0105] (1) SOC content calculation based on weighting

[0106] Since SOC (soil organic carbon) varies in different seasons, h is the total reduction thickness in a certain period, and the SOC or average value in a certain season cannot be simply used, the present application uses a time-weighted SOC to represent the average SOC concentration changing with time, so as to reflect the real carbon loss:

[0107]

[0108] (2) Take the seasonal average of bulk density

[0109] Soil bulk density (BD) as a core parameter reflecting the compaction state and physical structure of soil, is relatively limited in the short term by natural and engineering disturbance, and the change amplitude between seasons is usually small. A large number of measured results and related literature show that under the condition of no severe disturbance or special rainfall event, the seasonal change rate of soil bulk density is generally less than 5%. Therefore, in the process of carbon loss calculation, for the carbon loss or sequestration dynamics between two seasons, the present application uses the arithmetic mean of the bulk densities of the two seasons before and after, which can not only reflect the small changes of soil state, but also avoid the accidental errors of single point data. This processing simplifies the parameter input, enhances the applicability and practicability of the carbon loss quantitative model, and at the same time ensures the scientificity and representativeness of the calculation results.

[0110] (3) Calculation formula of slope carbon loss and sequestration

[0111] Slope carbon loss calculation formula (applicable to erosion area):

[0112]

[0113] Slope carbon loss oxidation amount:

[0114]

[0115] Slope carbon sequestration calculation formula (applicable to deposition area or natural control area):

[0116]

[0117] Slope carbon sequestration oxidation amount (applicable to deposition area or natural control area):

[0118]

[0119] The formula for calculating carbon loss caused by water and soil loss on the same elevation slope is:

[0120]

[0121] Parameter description:

[0122] SOC w : Weighted SOC content (unit: g / kg), SOC1 is the SOC content of the first quarter, SOC2 is the SOC content of the second quarter, the second quarter is the next quarter of the first quarter, and the soil organic carbon content is determined by potassium dichromate oxidation-external heating method;

[0123] H: The depth of soil sampling, the value is 0.2 (unit: m);

[0124] H: Cumulative erosion or accumulation depth (unit: m), calculated by the difference in the exposed height of the erosion stake, positive value indicating erosion, negative value indicating accumulation;

[0125] A: Observation plot area (unit: m²), in this study, each plot area is 5m x 20m, i.e. 100 m²;

[0126] BD: Soil bulk density (unit: g / cm³), determined by the cutting ring method, reflecting the mass of soil per unit volume;

[0127] P se : Organic carbon oxidation coefficient, representing the proportion of organic carbon oxidized and released as CO2 during soil transport and disturbance, taking a value of 0.2 based on previous research and the principle of conservatism.

[0128] The above series of formulas can convert the surface soil carbon migration of different types of slope areas into quantifiable carbon loss or carbon sequestration values, accurately revealing the spatial distribution pattern of carbon loss-carbon sink under different disturbance scenarios. The change in the exposed height of the erosion stake is used to determine the direction of carbon migration: an increase in height corresponds to carbon loss (positive value), and a decrease in height corresponds to accumulation carbon sequestration (negative value). The carbon loss model represented by the formula is simple in structure based on physical parameters, avoiding the complexity of distributed models, and is suitable for carbon effect evaluation and carbon sink engineering planning in multiple scenarios such as before and after engineering, disturbance and recovery, and regional comparison.

[0129] The application creatively fuses continuous monitoring of ground erosion pile and high-frequency soil physical and chemical analysis, breaks through the time and space limitations of traditional single physical measurement or low-frequency sampling, and realizes the whole process and high-resolution dynamic quantification of road slope water and soil loss and induced carbon loss. The "time-weighted average SOC and bulk density coupling" method is proposed to enhance the scientificity and regional applicability of the model, which can accurately analyze the spatial heterogeneity characteristics of carbon loss / sequestration in erosion and accumulation areas. The technical system has the advantages of standardized operation, traceable data, strong regional adaptability, etc., and is especially suitable for long-term continuous monitoring in plateau mountainous and complex engineering disturbed areas, providing a standardized technical solution for the research on carbon migration on the earth's slope, ecological restoration engineering and carbon neutral strategy evaluation.

[0130] Examples are described:

[0131] Research site 1 is located in the eastern edge of the Qinghai-Tibet Plateau in western Sichuan, belonging to the sub-temperate plateau humid climate zone, with obvious vertical difference, forming a unique plateau continental monsoon climate. The annual average temperature is about 7℃, the extreme minimum temperature is-14℃, the extreme maximum temperature is 29℃, the annual sunshine hours is 1738 hours, and the frost-free period is 177 days. The area has abundant rainfall in summer and frequent snowfall in winter. The annual average temperature and annual average precipitation are 5.6°C and 950 mm respectively. The vegetation types are mainly divided into meadow, shrub, forest and other categories according to the altitude from low to high. The soil types have vertical zonation characteristics, and from low to high, the main zonal soils are brown soil, brown soil, alpine meadow soil, alpine meadow soil, alpine cold desert soil, and perennial snow belt.

[0132] Research site 2 is located in the eastern edge of the Qinghai-Tibet Plateau. The area is located in the three rivers and one river area (Angqu, Zhaqu, Sequ, Lancang River), which means "water convergence" in Tibetan language, belonging to the plateau sub-temperate sub-humid climate, with mild and humid climate in summer and dry and cold climate in winter, small annual temperature difference and large daily temperature difference. The annual average sunshine hours is 2100-2700 hours, the annual frost-free period is 46-162 days, the annual precipitation is 477.7 mm, which concentrates in May-September. The annual average temperature is 7.6℃, the annual rainfall is 400-600 mm, and the frost-free period is 80-127 days. The average precipitation is 477.7 mm, mainly concentrated in June-September, accounting for 74.9% of the annual rainfall. The vegetation type belongs to the plateau mountain cold-temperate coniferous forest belt, and the surrounding vegetation types are mainly xerophytic thorny shrubs and herbaceous plants, with whiteflower, rose and raspberry as the main shrubs; the grasses are mainly artemisia, fern, and herbaceous grasses. The soil is mainly gray-brown soil, with soil layer thickness of 0.1m~2.50m, belonging to the eastern Tibetan brown soil and brown soil zone, and the representative soil structure is the plateau forest alpine meadow soil belt spectrum, with main soil types of brown soil, brown soil, brown soil, acid brown soil, gray soil, brown soil, black soil, grass soil and cold soil.

[0133] The example selects two typical subalpine forest shrubs in two regions, with disturbed slope surfaces under road construction as the research object. Different altitude gradient slopes are set up, with natural state slopes at the same altitude as the control. Erosion stake plots are set up, and the road engineering slope excavation lasts more than 1 year to form a stable slope. Each monitoring plot is 5 meters x 20 meters in area, with 18 stakes set up every 2.5 meters in the width direction and every 4 meters in the length direction. The 1.2 cm diameter, 50 cm long steel pegs are driven vertically into the slope or platform, with the peg cap flush with the slope or platform, and the exposed part of the ground is sprayed with red paint and numbered and registered. Every 3 months, the exposed ground height of the peg cap is observed. During the installation of the erosion stakes, avoid disturbing the surrounding soil and reduce the impact on the natural erosion process. Ensure the verticality of the erosion stakes to reduce measurement errors. Record the specific location, installation date, and soil conditions of each erosion stake. Set up warning signs around the erosion stakes to prevent human damage. Record all the spatial information, soil conditions, and observation environment of the erosion stakes, and take photos with a camera to assist in analysis.

[0134] The monitoring task is heavy, with WBQ and KD in two regions. In the research area KD, 6 altitude gradients are arranged, totaling 12 observation plots, with a height difference of 100-120m between the two plots. In the research area WBQ, 3 altitude gradients are arranged, totaling 6 observation plots, with a height difference of 50m between the two plots.

[0135] Figure 2 is a soil bulk density change chart for different plots at different times, which specifically shows the soil bulk density change characteristics of each monitoring plot in August 2024, November 2024, and March 2025. The monitoring results show that the soil bulk density of most plots changes little within half a year, and the soil bulk density values are stable between seasons in the short term, with an average change of not more than 0.05 g / cm³, reflecting the inertial characteristics of the physical structure of the slope soil after engineering disturbance. The disturbed area plots have a significantly higher bulk density than the natural control area due to previous mechanical rolling, construction disturbance, and other factors, with an average increase of 0.10-0.15 g / cm³, but as vegetation restoration and soil biological activity gradually increase, the bulk density of some plots shows a slow downward trend, reflecting the gradual loosening of soil structure and the positive effects of ecological restoration. The bulk density of most plots remains at a high level after disturbance, but there is no significant decrease or increase.

[0136] Further comparison found that even in the rainy season or after the construction period, the seasonal fluctuation of soil bulk density at short time scale was still limited, which was consistent with the previous understanding of the short-term stability of soil bulk density on slope. The study believed that the change of bulk density was mainly affected by long-term cumulative disturbance and soil structure evolution, rather than seasonal climate or short-term rainfall events. Therefore, in the quantitative estimation of slope carbon loss, the arithmetic mean of the bulk density of the two quarters before and after was selected as the calculation parameter, which could not only reflect the slow evolution of soil physical state, but also avoid the uncertainty introduced by single-point abnormal value. The relevant measured data showed that the use of average value processing could ensure the scientificity and representativeness of carbon loss estimation, simplify the model parameters, and improve the calculation efficiency. Overall, the dynamic stability of soil bulk density provided reliable support for the accurate estimation of slope SOC content change and carbon loss model.

[0137] Figure 3 is a graph showing the changes of soil organic carbon content in different plots at different times. It specifically shows the changes of soil organic carbon (SOC) content in different monitoring plots in August 2024 and November 2024. Overall, the SOC content in the disturbed area of the road slope and the natural control area showed obvious spatial and temporal differentiation and dynamic change. The SOC content in most disturbed plots was at a high level at the beginning of the monitoring (August 2024), and decreased significantly in November 2024 due to factors such as rainfall-induced soil erosion. The SOC content in some plots decreased by more than 5%. For example, in typical disturbed areas such as WBQ-3 and KD-5, the SOC content decreased from 35.2 g / kg to 31.1 g / kg, while the natural control plots showed stable or slightly increased SOC content, indicating that natural recovery and vegetation reconstruction had a significant effect on SOC maintenance. The seasonal decline of slope SOC is mainly related to rainfall erosion and surface soil transport, while the increase at the end of the season reflects the combined effect of organic matter accumulation and surface vegetation growth recovery.

[0138] Figure 4 is a graph showing the changes of soil erosion depth in different plots at different times. The graph reflects the changes of erosion and deposition depth in typical slope plots from August 2024 to March 2025. Based on the erosion stake observation method, it can accurately capture the dynamic process of slope material migration. The monitoring results showed that the erosion rate in the engineering disturbed area was much higher than that in the natural control area, with a maximum quarterly average erosion depth of more than 0.5 cm. For example, in KD-5 and WBQ-3, the cumulative erosion from August 2024 to November 2024 reached 1.8 cm.

[0139] The spatial difference of erosion / accumulation is closely related to slope, slope direction, vegetation coverage and rainfall. In the disturbed area, due to the lack of vegetation, soil exposure and severe slope disturbance, surface soil loss occurs easily during the rainy season, resulting in a significant increase in erosion depth. In the control area, due to the good surface vegetation and stable soil structure, the erosion rate is significantly lower than that in the engineering area, and on the contrary, soil accumulation occurs. This result further shows that the slope material migration is the basic dynamic process of SOC loss and carbon loss.

[0140] Figure 5 Fig. 1 is a comparison diagram of SOC accumulation and loss in different plots, which specifically shows the quantitative results of SOC loss and accumulation of different plot slopes in the WBQ and KD areas in the study area within half a year. All data are the quarterly erosion and accumulation thickness monitored by the erosion pile method, combined with the physicochemical property index, and the calculation of SO soil carbon loss and accumulation is completed according to the series of formulas in the present application.

[0141] The SOC loss amount in the erosion area of the WBQ area is significantly higher than the SOC accumulation amount in the accumulation area. In the WBQ area, such as WBQ-3, WBQ-5 and the like, the half-year SOC loss amount is higher than 0.08 kg / 100 m², which is much higher than the SOC sequestration level of the accumulation area (mostly 0.01-0.03 kg / 100 m²). This reflects that the soil and water loss intensity of the slope surface in this area is large, the rainfall convergence is concentrated, and the surface soil loss is intensified. Although the accumulation area shows a certain SOC net sequestration, the overall compensation range is limited, and it is difficult to offset the high-intensity carbon loss in the erosion area.

[0142] The SOC sequestration amount in the accumulation area of the KD area is higher than the SOC loss amount in the erosion area. The SOC accumulation amount in most natural areas (such as KD-2, KD-4 and the like) is significantly higher than the SOC loss amount in the erosion area of the same area, and the half-year SOC net sequestration amount can reach 0.04-0.06 kg / 100 m², and the loss amount in the erosion area is relatively low. The reason is analyzed, the slope of the KD area is gentle and the terrain is closed, which is easy to form the downward migration and collection of silt and organic carbon.

[0143] The WBQ area has less snow in winter, low vegetation coverage, and high SOC loss rate; the KD area has more rainfall, high vegetation coverage, and closed terrain. This partition comparison not only reveals the regulation effect of different engineering areas on regional SOC migration, but also provides targeted decision-making reference for ecological restoration and carbon management in different areas. The advantage of the method of the present application is that it can accurately distinguish the carbon loss and carbon sequestration of different spatial units of the slope surface, realize the spatial heterogeneity of the SOC migration flux and the dual revelation of the total amount of the region.

[0144] Figure 6is a slope soil and water loss sample plot carbon loss comparison chart, specifically, the slope comprehensive carbon loss quantitative results of each monitoring sample plot within half a year (about 180 days). All SOC loss and accumulation data are based on the erosion / accumulation thickness monitored by the erosion pile, combined with the measured SOC content and soil bulk density in each quarter, and the dynamic quantification is carried out by using the time-weighted average of SOC concentration and bulk density. The analysis results show that:

[0145] The SOC loss amount in the erosion area of the slope within half a year is generally between 0.07 and 0.10 kg / 100 m², and the carbon loss value of some high disturbance sample plots such as WBQ-5 is significantly higher than the regional average, reaching more than 0.09 kg / 100 m². This value is significantly higher than the accumulation area and the historical natural slope background in the same region, reflecting that the soil organic carbon pool of the slope is continuously outflowed due to soil and water loss in the disturbance area of road engineering construction, which is the main driving force of regional carbon loss.

[0146] Further statistics of the total SOC loss amount of all sample plots in the erosion area show that the average SOC loss per unit area in the erosion area within half a year is 0.085 kg / 100 m², and the annualized value is 0.17 kg / 100 m², which is in the medium-low range of the slope SOC migration rate in the same type of engineering area in China (related literatures report that it is 0.08~0.25 kg / 100 m²). In terms of spatial distribution, the carbon loss amount in the erosion area is closely related to the erosion depth, the initial content of SOC and the surface disturbance intensity, and the loss is most concentrated in the middle and foot of the slope.

[0147] The comprehensive analysis shows that the slope erosion area is the core area of regional soil carbon loss, and its carbon loss level has an important influence on the slope carbon balance, the safety of the watershed carbon sink and the regional carbon peak and carbon neutralization target. The method significantly improves the scientificity and quantification level of carbon loss monitoring. The method of the present application provides high-precision and practical basic data and basis for risk assessment of carbon loss in the erosion area, evaluation of engineering repair effect and determination of ecological compensation quota.

[0148] In order to better illustrate the present application, numerous specific details are given in the foregoing specific embodiments. Those skilled in the art should understand that the present application can also be implemented without some specific details. In some examples, methods, means, elements and circuits familiar to those skilled in the art are not described in detail, in order to highlight the main idea of the present application.

[0149] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of ground monitoring of carbon loss from road side slope soil erosion, characterized by, The method comprises the following steps: Step S1: Preselect observation points according to regional soil erosion distribution, vegetation coverage and altitude gradient, wherein a 100-meter altitude difference is taken as the gradient division basis for regions with mountain altitudes greater than 500 meters, and a 50-meter altitude difference is taken as the gradient division basis for regions with mountain altitudes less than 500 meters, and an engineering disturbance area and a natural control area are set at each altitude gradient, and the slope difference between the two is less than or equal to ±2°, and the aspect difference is less than or equal to ±10°, and the engineering disturbance area is a stable slope with an excavation duration of more than 1 year; the size of each monitoring sample site in the engineering disturbance area and the natural control area is 5m x 20m, and a plurality of erosion stakes are arranged at an interval of every 2.5m in the width direction and every 4m in the length direction; Step S2: After removing the surface vegetation, litter and rocks in the monitoring sample site, evenly distribute points in the sample site to collect 0~20cm soil layer, total amount≥500g of loose soil samples, and simultaneously collect soil samples by the cutting ring method for bulk density determination; record the environmental parameters such as the geographical position, altitude, slope, aspect and vegetation coverage of the sample site; the loose soil sample collection adopts a five-point quincunx or chessboard point distribution method to avoid root dense areas to ensure sample representativeness; the cutting ring sample needs to be vertically pressed into the soil, and after cutting off the excess soil body, it is sealed and stored, and the analysis and detection are completed within 24 hours; Step S3: After the collected soil samples are naturally dried, plant roots and stones with a particle size greater than 2mm are removed, and after fine grinding through a 0.15mm sieve, the samples are divided for determination of the soil organic carbon content of each quarter; the soil bulk density is determined by the cutting ring method, and the soil organic carbon content is determined by the potassium dichromate oxidation-external heating method; Step S4: During the continuous observation period, the newly exposed height of all erosion stakes is measured every quarter, and the erosion / deposition modulus is calculated, and the observation date, weather and potential impact events are recorded simultaneously, and a time and space database of the erosion process is established; Step S5: Calculate the carbon loss based on the physical parameters.

2. The ground monitoring method for carbon loss of road slope soil erosion according to claim 1, wherein: In step S1, it further comprises: marking the erosion stake number, recording the initial exposed height and soil initial condition, observing once every 3 months, and recording the weather and potential impact events simultaneously.

3. The ground monitoring method for carbon loss of road slope soil erosion according to claim 2, wherein: In step S3, the soil bulk density is determined by the cutting ring method, which specifically comprises: weighing the empty cutting ring and the cutting ring with wet soil, after being saturated by water absorption, dried and balanced, and then baked to constant weight, the soil mass moisture content, volume moisture content, bulk density and porosity parameters are calculated.

4. The ground monitoring method for carbon loss of road slope soil erosion according to claim 3, wherein: In step S3, the soil organic carbon content is determined by the potassium dichromate oxidation-external heating method, which specifically comprises: weighing the sieved and dried soil sample, sequentially adding potassium dichromate solution, concentrated sulfuric acid and silver sulfate, boiling in an oil bath at 170~180℃ for 5min, cooling, using phenanthroline as an indicator, titrating with ferrous sulfate until the brown-red end point, and calculating the organic carbon content according to the titration volume.

5. The ground monitoring method for carbon loss of road slope soil erosion according to claim 4, wherein: In step S5, the physical parameters include: observed plot area, cumulative erosion or deposition depth, soil bulk density, soil organic carbon content, soil sampling depth, and organic carbon oxidation coefficient.

6. The method of claim 5, wherein the method further comprises: The soil organic carbon content is equal to where SOC1is the soil organic carbon content of the first quarter, SOC2is the soil organic carbon content of the second quarter, the second quarter being the next quarter after the first quarter; H is the depth of soil sampling, H is the cumulative erosion or deposition depth.

7. The method of claim 6, wherein the method further comprises: The step S5 calculates the carbon loss based on the physical parameters, specifically: Carbon loss from slopes in eroded areas ; Slope carbon loss oxidation amount ; Carbon sequestration in slope of deposition area or natural control area ; Carbon sequestration and oxidation on slopes ; Carbon loss due to water and soil loss from the same slope aspect ; Where A is the area of the observed plot, BD is the soil bulk density, SOC is the soil organic carbon content, and H is the depth of soil sampling, H is the cumulative erosion or deposition depth, P se is the oxidation coefficient of organic carbon.

8. The method of claim 7, wherein the method further comprises: The step S1 further comprises: For regular observation, the exposed height of the steel drill is measured every 3 months, and sunny and rainless weather is selected. The steel ruler is used to measure the vertical distance from the ground surface to the top of the steel drill, and the measurement is repeated 3 times to take the average value; For intensive observation, temporary observation is increased within 48 hours after heavy rain and strong erosion events such as snowmelt, and abnormal erosion amount is recorded; wherein, The erosion stake is the steel drill.

9. The method of claim 8, wherein the method further comprises: In step S4, the environmental factors recorded synchronously every quarter further include: observation date, weather conditions including temperature, humidity, and rainfall intensity; potential impact events including construction, grazing, and pest damage; and steel drill appearance inspection including whether it is tilted, displaced, or damaged.

10. The method of claim 7, wherein the method further comprises: The soil bulk density is the arithmetic mean of the first quarter soil bulk density and the second quarter soil bulk density.

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