A method and system for detecting soil salt crust in coastal areas

Abstract

The present invention relates to the technical field of salt crust detection, and discloses a method and system for detecting soil salt crust in coastal areas. The method comprises: obtaining the soil surface albedo of a target detection area to determine whether the target detection area is an area with high coverage of soil salt crust; if it is determined to be an area with high coverage of soil salt crust, collecting several groups of soil salt crust samples; scanning the soil salt crust samples using a CT scanner to obtain porosity vertical distribution data, and then determining the first salt crust thickness of the soil salt crust samples; detecting the soil salt crust samples using a spectrometer to obtain spectral vertical distribution data, and then determining the second salt crust thickness of the soil salt crust samples; and determining the soil salt crust thickness in the target detection area based on the first salt crust thickness and the second salt crust thickness. By combining porosity data and spectral data, the present invention can more accurately assess the thickness of the soil salt crust, thereby improving the accuracy of detection.

Description

Technical Field

[0001] The present invention relates to the technical field of salt crust detection, and in particular to a method and system for detecting soil salt crust in coastal areas. Background Art

[0002] Soil salt crusts are common in coastal areas. Salt crusts are a unique surface structure formed by the accumulation and crystallization of salt in the soil. They have significant impacts on the ecological environment, agricultural production, and infrastructure development in coastal areas. For example, in agriculture, salt crusts can affect seed germination and crop growth; in infrastructure, they can cause salt corrosion damage to roads and building foundations. However, traditional methods for detecting soil salt crusts often have limitations. Some methods may not be able to quickly and accurately determine areas with high salt crust coverage in the field. Furthermore, when measuring salt crust thickness, a single technique may not be able to fully and accurately determine its true thickness. Because salt crusts have a complex structure and composition, different measurement methods may be subject to interference from multiple factors, resulting in errors. Therefore, a more accurate and efficient method for detecting soil salt crusts in coastal areas that comprehensively considers multiple factors is needed. Summary of the Invention

[0003] The purpose of the present invention is to provide a method and system for detecting soil salt crust in coastal areas, aiming to solve the above problems.

[0004] The present invention provides a method for detecting soil salt crust in coastal areas, comprising:

[0005] Obtaining the soil surface albedo of the target detection area, and determining whether the target detection area is an area with high coverage of soil salt crust according to the soil surface albedo;

[0006] If the target detection area is determined to be an area with high coverage of soil salt crust, a ring knife is used to collect several groups of soil salt crust samples;

[0007] Scanning the soil salt crust sample using a CT scanner to obtain porosity vertical distribution data of the soil salt crust sample, and determining the first salt crust thickness of the soil salt crust sample based on the porosity vertical distribution data;

[0008] Detecting the soil salt crust sample using a spectrometer to obtain spectral vertical distribution data of the soil salt crust sample, and determining the second salt crust thickness of the soil salt crust sample based on the spectral vertical distribution data;

[0009] The soil salt crust thickness in the target detection area is determined according to the first salt crust thickness and the second salt crust thickness.

[0010] Preferably, determining whether the target detection area is an area with high coverage of soil salt crust according to the soil surface albedo includes:

[0011] Acquiring soil surface moisture content and a surface area of ​​the target detection region, and determining a salt-free soil surface albedo of the salt-free soil based on the soil surface moisture content;

[0012] Based on the surface area of ​​the target detection area, determining the salt crust coverage area of ​​the target detection area according to the soil surface albedo and the salt-free soil surface albedo;

[0013] Determining the salt crust coverage ratio of the target detection area according to the salt crust coverage area;

[0014] Based on the salt crust coverage ratio, it is determined whether the target detection area is a soil salt crust high coverage area.

[0015] Preferably, obtaining the soil surface moisture content in the target detection area and determining the salt-free soil surface albedo of the salt-free soil based on the soil surface moisture content includes:

[0016] Collect salt-free soil surface samples in the target detection area and determine the soil surface moisture content in the target detection area using direct measurement method;

[0017] The albedo of the salt-free soil surface is determined based on the range of soil surface moisture content;

[0018] Among them, if the soil surface moisture content is less than 0.1, the surface albedo of salt-free soil is 0.25;

[0019] If 0.1≤soil surface moisture content<0.25, then the albedo of salt-free soil surface is 0.35-soil surface moisture content;

[0020] If the soil surface moisture content is ≥0.25, the surface albedo of salt-free soil is 0.1.

[0021] Preferably, based on the surface area of ​​the target detection area, when determining the salt crust coverage area of ​​the target detection area according to the soil surface albedo and the salt-free soil surface albedo, the salt crust coverage area is determined by the following formula:

[0022] ;

[0023] Among them, A SC represents the area covered by salt crust, A C represents the surface area of ​​the target detection area, α SC represents the soil surface albedo, α C represents the surface albedo of salt-free soil, and a represents the fitting coefficient.

[0024] Preferably, determining the first salt crust thickness of the soil salt crust sample according to the porosity vertical distribution data comprises:

[0025] Based on the porosity vertical distribution data, the porosity change rate between the porosity value of each layer and the porosity value of the adjacent next layer is determined, the difference ratio of adjacent porosity change rates is determined, the maximum value of the difference ratio is determined, and the number of layers of soil salt crust samples corresponding to the maximum value of the difference ratio is obtained. The depth corresponding to the number of layers is set as the first salt crust thickness of the soil salt crust sample.

[0026] Preferably, determining the first salt crust thickness of the soil salt crust sample according to the porosity vertical distribution data comprises:

[0027] Set the thickness of the soil salt crust sample to h, and set the number of layers of the soil salt crust sample in order from top to bottom;

[0028] Calculate the mean porosity of layers 1 to n and the mean porosity of layers n+1 to h;

[0029] If the mean porosity values ​​of layers 1 to 2, 1 to 3, ..., and 1 to n are different, and the mean porosity values ​​of layers n+1 to h, n+2 to h, ..., and h-1 to h are the same, then the depth corresponding to layer n is determined as the thickness of the first salt crust of the soil salt crust sample.

[0030] Preferably, determining the second salt crust thickness of the soil salt crust sample according to the spectral vertical distribution data comprises:

[0031] determining a soil crust index of each layer of soil salt crust sample according to the spectral vertical distribution data;

[0032] Determine the soil crust index setting range based on the soil crust index of salt-free soil;

[0033] Determine from top to bottom whether the soil crust index of each layer of soil salt crust sample is within the set range of the soil crust index. If it is within the range, determine that the depth of the previous layer corresponding to the time when the soil crust index of the soil salt crust sample is within the set range of the soil crust index is the second salt crust thickness of the soil salt crust sample.

[0034] Preferably, when determining the soil crust index of each layer of soil salt crust sample based on the spectral vertical distribution data, the soil crust index is determined according to the following formula:

[0035] ;

[0036] Where SC represents the soil crust index, R represents the red light band reflectance, G represents the green light band reflectance, L represents the correction coefficient for the difference between R and G, and GRNIR represents the average value of the red light band, green light band, and near-infrared band.

[0037] Preferably, determining the soil salt crust thickness in the target detection area according to the first salt crust thickness and the second salt crust thickness includes:

[0038] An average value of the first salt crust thickness and the second salt crust thickness is determined, and the average value is set as the soil salt crust thickness of the target detection area.

[0039] The present invention also discloses a coastal area soil salt crust detection system, which is used to apply the coastal area soil salt crust detection method, comprising:

[0040] a salt crust area determination module, configured to obtain a soil surface albedo of a target detection area, and determine whether the target detection area is an area with high coverage of soil salt crust according to the soil surface albedo;

[0041] The soil salt crust sampling module is configured to collect several groups of soil salt crust samples using a circular knife if the target detection area is determined to be an area with high coverage of soil salt crust;

[0042] a porosity data processing module configured to scan the soil salt crust sample using a CT scanner to obtain vertical porosity distribution data of the soil salt crust sample, and determine a first salt crust thickness of the soil salt crust sample based on the vertical porosity distribution data;

[0043] a spectral data processing module configured to detect the soil salt crust sample using a spectrometer to obtain spectral vertical distribution data of the soil salt crust sample, and determine the second salt crust thickness of the soil salt crust sample based on the spectral vertical distribution data;

[0044] The salt crust thickness determination module is configured to determine the soil salt crust thickness in the target detection area according to the first salt crust thickness and the second salt crust thickness.

[0045] Compared with existing technologies, the present invention offers the advantage of determining areas with high salt crust coverage by measuring soil surface albedo. This method allows for rapid preliminary assessments in natural field conditions. Compared with traditional point-by-point sampling and analysis methods, it more efficiently identifies areas requiring detailed testing, saving significant manpower and time, and improving detection efficiency.

[0046] A CT scanner was used to scan soil salt crust samples to obtain vertical porosity distribution data to determine the thickness of the first salt crust. CT scanning clearly reveals the internal structural details of the sample and is very effective for analyzing the relationship between porosity changes and salt distribution within the salt crust, thereby accurately determining the thickness of the salt crust at the level of porosity variation. A spectrometer was used to examine the soil salt crust samples to obtain vertical spectral distribution data to determine the thickness of the second salt crust. A spectrometer can detect the absorption and reflection characteristics of different components in the salt crust. Because salt and other substances have different spectral responses, the vertical spectral distribution can accurately identify the boundaries of the salt crust and determine its thickness. The thickness of the soil salt crust in the target area is determined by combining the thickness of the first and second salt crusts, avoiding the interference and errors that may be encountered with a single measurement method. Different measurement methods measure salt crust thickness from different perspectives (internal structure and spectral characteristics), verifying and complementing each other, significantly improving the accuracy and reliability of salt crust thickness measurements. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0048] Figure 1 The present invention is a flow chart of a method for detecting soil salt crust in coastal areas.

[0049] Figure 2 This is a functional block diagram of a soil salt crust detection system for coastal areas according to the present invention. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0051] like Figure 1 As shown, the present invention provides a method for detecting soil salt crust in coastal areas, comprising: obtaining the soil surface albedo of a target detection area, and determining whether the target detection area is a soil salt crust high coverage area according to the soil surface albedo.

[0052] If the target detection area is determined to be an area with high coverage of soil salt crust, a ring knife is used to collect several groups of soil salt crust samples.

[0053] The soil salt crust sample is scanned by using a CT scanner to obtain vertical porosity distribution data of the soil salt crust sample, and the first salt crust thickness of the soil salt crust sample is determined according to the vertical porosity distribution data.

[0054] The soil salt crust sample is detected by using a spectrometer to obtain spectral vertical distribution data of the soil salt crust sample, and the second salt crust thickness of the soil salt crust sample is determined according to the spectral vertical distribution data.

[0055] The soil salt crust thickness in the target detection area is determined according to the first salt crust thickness and the second salt crust thickness.

[0056] By combining vertical porosity and spectral distribution data, this method can more accurately assess the thickness of soil salt crusts, improving detection precision. Furthermore, the use of modern instruments such as CT scanners and spectrometers improves detection efficiency and accuracy, providing strong technical support for the research and management of soil salt crusts in coastal areas.

[0057] In some embodiments of the present application, determining whether the target detection area is an area with high coverage of soil salt crust is determined based on the soil surface albedo, including: obtaining the soil surface moisture content and the surface area of ​​the target detection area, and determining the salt-free soil surface albedo of the salt-free soil based on the soil surface moisture content; determining the salt crust coverage area of ​​the target detection area based on the soil surface albedo and the salt-free soil surface albedo based on the surface area of ​​the target detection area; determining the salt crust coverage ratio of the target detection area based on the salt crust coverage area; and determining whether the target detection area is an area with high coverage of soil salt crust based on the salt crust coverage ratio.

[0058] It can be understood that by introducing the parameter of soil surface albedo, the salt crust coverage of the target detection area can be evaluated more accurately. First, by obtaining the soil surface moisture content and the surface area of ​​the target detection area, the salt-free soil surface albedo of the salt-free soil can be calculated. This step provides basic data for the subsequent calculation of the salt crust coverage area. Then, by combining the soil surface albedo and the salt-free soil surface albedo, the salt crust coverage area of ​​the target detection area can be accurately determined. This data is of great significance for evaluating the distribution of salt crusts. Furthermore, the salt crust coverage ratio is calculated based on the salt crust coverage area, which can intuitively reflect the degree of salt crust coverage in the target detection area. Finally, based on the salt crust coverage ratio, it can be determined whether the target detection area is an area with high soil salt crust coverage.

[0059] In this embodiment, the soil surface albedo can be obtained by:

[0060] (1) Laboratory measurement

[0061] Principle: Under controlled conditions, a light source is used to simulate solar radiation and measure the reflectivity of soil samples in the target detection area.

[0062] Steps: Collect a soil sample and ensure the surface is flat. Use a spectrometer or spectrophotometer to measure the reflectance of the soil surface in a specific wavelength band (e.g., visible light, near-infrared).

[0063] Calculate albedo: Albedo = reflected radiation flux / incident radiation flux.

[0064] Optional: Spectrometers, such as UV-VIS-NIR spectrometers, can measure multi-band reflectance. Spectrophotometers, for single-band or multi-band reflectance measurements. Integrating spheres, for evenly illuminating the sample and collecting reflected light to improve measurement accuracy.

[0065] (2) Field measurement

[0066] Principle: In a natural environment, the reflectance of the soil surface is directly measured using a portable instrument.

[0067] Steps: Select a representative sample plot and ensure the soil surface is flat and unobstructed. Use a portable spectrometer or albedo meter to measure the reflectance of the soil surface in a vertical direction. Record environmental parameters such as solar altitude and weather conditions for subsequent calibration.

[0068] Optional: Portable spectrometers, such as the ASD FieldSpect®, can quickly measure multi-band reflectance. Albedo meters, specifically designed to measure surface albedo, typically include multiple bands (such as visible light and near-infrared). Sun photometers, used to measure incident solar radiation and calculate albedo based on reflectance.

[0069] In some embodiments of the present application, the soil surface moisture content of the target detection area is obtained, and the salt-free soil surface albedo of the salt-free soil is determined based on the soil surface moisture content, including: collecting salt-free soil surface samples in the target detection area, and determining the soil surface moisture content of the target detection area by direct measurement; determining the salt-free soil surface albedo of the salt-free soil according to the range of soil surface moisture content; wherein, if the soil surface moisture content is less than 0.1, the salt-free soil surface albedo is 0.25; if 0.1≤soil surface moisture content<0.25, the salt-free soil surface albedo is 0.35-soil surface moisture content; if the soil surface moisture content is ≥0.25, the salt-free soil surface albedo is 0.1.

[0070] In this embodiment, the soil surface moisture content can be obtained by:

[0071] The direct measurement method is to collect soil samples and directly measure their mass or volume water content, including the drying method and alcohol combustion method.

[0072] Drying method:

[0073] Collect a soil surface sample (usually 0-5 cm or 0-10 cm). Weigh the wet soil. Dry the sample in an oven (105°C) to a constant weight, then weigh the dry soil. Calculate the moisture content:

[0074] Moisture content (%) = (wet soil mass − dry soil mass) / dry soil mass × 100%.

[0075] Alcohol combustion method:

[0076] Collect a soil sample and weigh the wet soil. Add alcohol and burn it to evaporate the water, then weigh the dry soil. Calculate the water content.

[0077] In some embodiments of the present application, when determining the salt crust coverage area of ​​the target detection area based on the surface area of ​​the target detection area and according to the soil surface albedo and the salt-free soil surface albedo, the salt crust coverage area is determined by the following formula:

[0078] ;

[0079] Among them, A SC represents the area covered by salt crust, A C represents the surface area of ​​the target detection area, α SC represents the soil surface albedo, α C represents the surface albedo of salt-free soil, and a represents the fitting coefficient.

[0080] As can be seen, this method can accurately and rapidly assess the coverage of soil salt crusts in coastal areas, providing a scientific basis for monitoring and managing soil salinization. Compared to traditional soil salt crust detection methods, this method not only improves detection efficiency but also reduces labor and material costs. Furthermore, by introducing the fitting coefficient a, the accuracy of salt crust coverage calculations is further improved, making the detection results more reliable.

[0081] In some embodiments of the present application, the first salt crust thickness of the soil salt crust sample is determined according to the porosity vertical distribution data, including: based on the porosity vertical distribution data, determining the porosity change rate between the porosity value of each layer and the porosity value of the adjacent next layer, determining the difference ratio of adjacent porosity change rates, determining the maximum value of the difference ratio, obtaining the number of layers of the soil salt crust sample corresponding to the maximum value of the difference ratio, and setting the depth corresponding to the number of layers as the first salt crust thickness of the soil salt crust sample.

[0082] As can be seen, this solution can accurately quantify the thickness of soil salt crusts, providing key data support for in-depth research on the issue. Traditional methods often rely on manual observation and empirical judgment, making it difficult to accurately measure salt crust thickness. However, this technical solution, through the analysis of vertical porosity distribution data, achieves an objective and accurate assessment of salt crust thickness. This not only improves the scientific nature of soil salinization research but also provides a more precise reference for soil salinization control.

[0083] For example: the porosity data from top to bottom are (2, 3, 4, 5, 6, 7, 8, 8, 8, 8), and the porosity change rate corresponding to each layer is -50.00, -33.33, -25.00, -20.00, -16.67, -14.29, 0.00, 0.00, 0.00 (%). The maximum value of the difference ratio of adjacent porosity change rates is 1, that is, the depth corresponding to the sixth layer is the thickness of the first salt crust of the soil salt crust sample.

[0084] In some embodiments of the present application, the first salt crust thickness of the soil salt crust sample is determined according to the porosity vertical distribution data, including: setting the thickness of the soil salt crust sample to h, and setting the number of layers of the soil salt crust sample in order from top to bottom; calculating the porosity mean of 1~n layers and the porosity mean of n+1~h layers; if the porosity mean of 1~2 layers, the porosity mean of 1~3 layers,..., and the porosity mean of 1~n layers are different, and the porosity mean of n+1~h layers, the porosity mean of n+2~h layers,..., and the porosity mean of h-1~h layers are the same, then determining the depth corresponding to layer n as the first salt crust thickness of the soil salt crust sample.

[0085] It is clear that this solution can quickly and accurately determine the thickness of soil salt crusts in actual field environments, greatly improving detection efficiency. This not only saves manpower and material resources, but also improves the accuracy and reliability of measurements.

[0086] In some embodiments of the present application, the second salt crust thickness of the soil salt crust sample is determined according to the spectral vertical distribution data, including: determining the soil crust index of each layer of soil salt crust sample according to the spectral vertical distribution data; determining the soil crust index setting range according to the soil crust index of salt-free soil; judging in order from top to bottom whether the soil crust index of each layer of soil salt crust sample is within the soil crust index setting range, and if it is within the range, determining that the depth of the previous layer corresponding to the number of layers when the soil crust index of the soil salt crust sample is within the soil crust index setting range is the second salt crust thickness of the soil salt crust sample.

[0087] In some embodiments of the present application, when determining the soil crust index of each layer of soil salt crust sample based on the spectral vertical distribution data, the soil crust index is determined according to the following formula:

[0088] ;

[0089] Where SC represents the soil crust index, R represents the red light band reflectance, G represents the green light band reflectance, L represents the correction coefficient for the difference between R and G, and GRNIR represents the average value of the red light band, green light band, and near-infrared band.

[0090] In this embodiment, the soil crust index of each layer of soil salt crust sample is calculated using spectral vertical distribution data. The soil crust index is an indicator that evaluates the degree of salt crust formation on the soil surface by analyzing the spectral characteristics of the soil sample. The normal range of the soil crust index for salt-free soil is determined. This range is set based on the spectral characteristics of salt-free soil to distinguish between soil with and without salt crust. Starting from the top layer of the soil sample, the soil crust index of each layer is determined layer by layer to determine whether it falls within the set range of the soil crust index for salt-free soil. This judgment process is performed by comparing the soil crust index of each layer with the soil crust index range for salt-free soil. If the soil crust index of a layer falls within the set range, then the depth of the layer above this layer is the second salt crust thickness of the soil salt crust sample. This means that the soil crust within the depth range from the soil surface to the previous layer is a salt crust.

[0091] In some embodiments of the present application, determining the soil salt crust thickness in the target detection area according to the first salt crust thickness and the second salt crust thickness includes:

[0092] An average value of the first salt crust thickness and the second salt crust thickness is determined, and the average value is set as the soil salt crust thickness of the target detection area.

[0093] like Figure 2 As shown, the present invention also discloses a soil salt crust detection system in coastal areas, which is used to apply the above-mentioned soil salt crust detection method in coastal areas, including: a salt crust area determination module, which is configured to obtain the soil surface albedo of the target detection area, and determine whether the target detection area is a soil salt crust high coverage area based on the soil surface albedo.

[0094] The soil salt crust sampling module is configured to use a circular knife to collect several groups of soil salt crust samples if the target detection area is determined to be an area with high coverage of soil salt crust.

[0095] The porosity data processing module is configured to scan the soil salt crust sample using a CT scanner to obtain vertical porosity distribution data of the soil salt crust sample, and determine the first salt crust thickness of the soil salt crust sample based on the vertical porosity distribution data.

[0096] The spectral data processing module is configured to detect the soil salt crust sample using a spectrometer to obtain spectral vertical distribution data of the soil salt crust sample, and determine the second salt crust thickness of the soil salt crust sample according to the spectral vertical distribution data.

[0097] The salt crust thickness determination module is configured to determine the soil salt crust thickness in the target detection area according to the first salt crust thickness and the second salt crust thickness.

[0098] This invention can accurately and rapidly determine the thickness of soil salt crusts in coastal areas, improving detection efficiency. Furthermore, by combining multiple detection methods, such as CT scanning and spectrometer testing, it can comprehensively assess the physical and chemical properties of soil salt crusts, providing a scientific basis for subsequent soil management and improvement. Furthermore, the detection system offers advantages such as ease of operation and wide applicability, making it suitable for different types of coastal soil salt crust detection needs.

[0099] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0100] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0101] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0102] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for detecting soil salt crust in coastal areas, characterized in that: include: Obtaining the soil surface albedo of the target detection area, and determining whether the target detection area is an area with high coverage of soil salt crust according to the soil surface albedo; If the target detection area is determined to be an area with high coverage of soil salt crust, a ring knife is used to collect several groups of soil salt crust samples; Scanning the soil salt crust sample using a CT scanner to obtain porosity vertical distribution data of the soil salt crust sample, and determining the first salt crust thickness of the soil salt crust sample based on the porosity vertical distribution data; Detecting the soil salt crust sample using a spectrometer to obtain spectral vertical distribution data of the soil salt crust sample, and determining the second salt crust thickness of the soil salt crust sample based on the spectral vertical distribution data; The soil salt crust thickness in the target detection area is determined according to the first salt crust thickness and the second salt crust thickness.

2. The method for detecting soil salt crust in coastal areas according to claim 1, wherein Determining whether the target detection area is an area with high soil salt crust coverage according to the soil surface albedo includes: Acquiring soil surface moisture content and a surface area of ​​the target detection region, and determining a salt-free soil surface albedo of the salt-free soil based on the soil surface moisture content; Based on the surface area of ​​the target detection area, determining the salt crust coverage area of ​​the target detection area according to the soil surface albedo and the salt-free soil surface albedo; Determining the salt crust coverage ratio of the target detection area according to the salt crust coverage area; Based on the salt crust coverage ratio, it is determined whether the target detection area is a soil salt crust high coverage area.

3. The method for detecting soil salt crust in coastal areas according to claim 2, wherein: Acquiring the soil surface moisture content of the target detection area, and determining the salt-free soil surface albedo of the salt-free soil based on the soil surface moisture content, including: Collect salt-free soil surface samples in the target detection area and determine the soil surface moisture content in the target detection area using direct measurement method; The albedo of the salt-free soil surface is determined based on the range of soil surface moisture content; Among them, if the soil surface moisture content is less than 0.1, the surface albedo of salt-free soil is 0.25; If 0.1≤soil surface moisture content<0.25, then the albedo of salt-free soil surface is 0.35-soil surface moisture content; If the soil surface moisture content is ≥0.25, the surface albedo of salt-free soil is 0.

1.

4. The method for detecting soil salt crust in coastal areas according to claim 3, wherein: When determining the salt crust coverage area of ​​the target detection area based on the surface area of ​​the target detection area and according to the soil surface albedo and the salt-free soil surface albedo, the salt crust coverage area is determined by the following formula: ； Among them, A SC represents the area covered by salt crust, A C represents the surface area of ​​the target detection area, α SC represents the soil surface albedo, α C represents the surface albedo of salt-free soil, and a represents the fitting coefficient.

5. The method for detecting soil salt crust in coastal areas according to claim 1, wherein: Determining the first salt crust thickness of the soil salt crust sample according to the porosity vertical distribution data includes: Based on the porosity vertical distribution data, the porosity change rate between the porosity value of each layer and the porosity value of the adjacent next layer is determined, the difference ratio of adjacent porosity change rates is determined, the maximum value of the difference ratio is determined, and the number of layers of soil salt crust samples corresponding to the maximum value of the difference ratio is obtained. The depth corresponding to the number of layers is set as the first salt crust thickness of the soil salt crust sample.

6. The method for detecting soil salt crust in coastal areas according to claim 1, wherein: Determining the first salt crust thickness of the soil salt crust sample according to the porosity vertical distribution data includes: Set the thickness of the soil salt crust sample to h, and set the number of layers of the soil salt crust sample in order from top to bottom; Calculate the mean porosity of layers 1 to n and the mean porosity of layers n+1 to h; If the mean porosity values ​​of layers 1 to 2, 1 to 3, ..., and 1 to n are different, and the mean porosity values ​​of layers n+1 to h, n+2 to h, ..., and h-1 to h are the same, then the depth corresponding to layer n is determined as the thickness of the first salt crust of the soil salt crust sample.

7. The method for detecting soil salt crust in coastal areas according to claim 1, wherein: Determining the second salt crust thickness of the soil salt crust sample according to the spectral vertical distribution data includes: determining a soil crust index of each layer of soil salt crust sample according to the spectral vertical distribution data; Determine the soil crust index setting range based on the soil crust index of salt-free soil; Determine from top to bottom whether the soil crust index of each layer of soil salt crust sample is within the set range of the soil crust index. If it is within the range, determine that the depth of the previous layer corresponding to the time when the soil crust index of the soil salt crust sample is within the set range of the soil crust index is the second salt crust thickness of the soil salt crust sample.

8. The method for detecting soil salt crust in coastal areas according to claim 7, wherein: When determining the soil crust index of each layer of soil salt crust sample based on the spectral vertical distribution data, the soil crust index is determined according to the following formula: ； Where SC represents the soil crust index, R represents the red light band reflectance, G represents the green light band reflectance, L represents the correction coefficient for the difference between R and G, and GRNIR represents the average value of the red light band, green light band, and near-infrared band.

9. The method for detecting soil salt crust in coastal areas according to claim 1, wherein: Determining the soil salt crust thickness in the target detection area according to the first salt crust thickness and the second salt crust thickness includes: An average value of the first salt crust thickness and the second salt crust thickness is determined, and the average value is set as the soil salt crust thickness of the target detection area.

10. A coastal area soil salt crust detection system, used for applying the coastal area soil salt crust detection method according to any one of claims 1 to 9, characterized in that: include: a salt crust area determination module, configured to obtain a soil surface albedo of a target detection area, and determine whether the target detection area is an area with high coverage of soil salt crust according to the soil surface albedo; The soil salt crust sampling module is configured to collect several groups of soil salt crust samples using a circular knife if the target detection area is determined to be an area with high coverage of soil salt crust; a porosity data processing module configured to scan the soil salt crust sample using a CT scanner to obtain vertical porosity distribution data of the soil salt crust sample, and determine a first salt crust thickness of the soil salt crust sample based on the vertical porosity distribution data; a spectral data processing module configured to detect the soil salt crust sample using a spectrometer to obtain spectral vertical distribution data of the soil salt crust sample, and determine the second salt crust thickness of the soil salt crust sample based on the spectral vertical distribution data; The salt crust thickness determination module is configured to determine the soil salt crust thickness in the target detection area according to the first salt crust thickness and the second salt crust thickness.

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