Coastal region soil salt crust detection method and system

Abstract

The invention relates to the technical field of salt crust detection, and discloses a coastal region soil salt crust detection method and system, and the method comprises the steps: obtaining the soil surface albedo of a target detection region, and determining whether the target detection region is a soil salt crust high coverage region; if the soil salt crust high coverage area is determined, collecting a plurality of groups of soil salt crust samples; scanning the soil salt crust sample by using a CT scanner to obtain porosity vertical distribution data, and further determining a first salt crust thickness of the soil salt crust sample; detecting the soil salt crust sample by using a spectrograph to obtain spectrum vertical distribution data, and further determining a second salt crust thickness of the soil salt crust sample; and determining the soil salt crust thickness of the target detection area according to the first salt crust thickness and the second salt crust thickness. According to the method, the porosity data and the spectral data are combined, so that the thickness of the soil salt crust can be evaluated more accurately, and the detection accuracy is improved.

Description

Technical Field

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

[0002] In coastal areas, the phenomenon of soil salt crust is relatively common. Soil salt crust is a special surface structure formed by the continuous accumulation and crystallization of salts in the soil on the ground surface. It has an important impact on the ecological environment, agricultural production, and infrastructure construction in coastal areas. For example, in agricultural production, salt crust affects seed germination and crop growth; in infrastructure construction, it may cause salt erosion damage to roads, building foundations, etc. However, traditional methods for detecting soil salt crust often have certain limitations. Some methods may be difficult to quickly and accurately determine whether it is a high salt crust coverage area in the field, and for measuring the thickness of salt crust, a single technical means may not be able to comprehensively and accurately obtain its true thickness, because the structure and composition of salt crust are complex, and different measurement methods may be interfered by various factors and generate errors. Therefore, a more accurate, efficient, and comprehensive method for detecting soil salt crust in coastal areas 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, including: Obtaining the soil surface albedo of the target detection area, and determining whether the target detection area is a high soil salt crust coverage area according to the soil surface albedo; If it is determined that the target detection area is a high soil salt crust coverage area, then collecting several groups of soil salt crust samples by using a ring knife; Scanning the soil salt crust samples by using a CT scanner to obtain the vertical distribution data of the porosity of the soil salt crust samples, and determining the first salt crust thickness of the soil salt crust samples according to the vertical distribution data of the porosity; Detecting the soil salt crust samples by using a spectrometer to obtain the vertical distribution data of the spectrum of the soil salt crust samples, and determining the second salt crust thickness of the soil salt crust samples according to the vertical distribution data of the spectrum; Determining the soil salt crust thickness of the target detection area according to the first salt crust thickness and the second salt crust thickness.

[0005] Preferably, determining whether the target detection area is a high soil salt crust coverage area according to the soil surface albedo includes: Acquiring soil surface moisture content and a surface area of the target detection area, 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.

[0006] 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: 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.

[0007] 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: ; 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.

[0008] Preferably, determining the first salt crust thickness of the soil salt crust sample according to the porosity vertical distribution data comprises: 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.

[0009] Preferably, determining the first salt crust thickness of the soil salt crust sample according to the vertical porosity distribution data includes: Set the thickness of the soil salt crust sample as h, and set the number of layers of the soil salt crust sample in the order from top to bottom; Calculate the average porosity of layers 1 to n and the average porosity of layers n + 1 to h; If the average porosity of layers 1 to 2, the average porosity of layers 1 to 3,..., the average porosity of layers 1 to n are different, and the average porosity of layers n + 1 to h, the average porosity of layers n + 2 to h,..., the average porosity of layers h - 1 to h are the same, then determine the depth corresponding to layer n as the first salt crust thickness of the soil salt crust sample.

[0010] Preferably, determining the second salt crust thickness of the soil salt crust sample according to the vertical spectral distribution data includes: Determine the soil crust index of each layer of the soil salt crust sample according to the vertical spectral distribution data; Determine the set range of the soil crust index according to the soil crust index of the salt - free soil; Judge and set whether the soil crust index of each layer of the soil salt crust sample is within the set range of the soil crust index in the order from top to bottom. If it is within the range, then determine the depth of the upper layer corresponding to the layer number when the soil crust index of the soil salt crust sample is within the set range of the soil crust index as the second salt crust thickness of the soil salt crust sample.

[0011] Preferably, when determining the soil crust index of each layer of the soil salt crust sample according to the vertical spectral distribution data, the soil crust index is determined according to the following formula: ; where SC represents the soil crust index, R represents the reflectance in the red light band, G represents the reflectance in the green light band, L represents the correction coefficient of the difference between R and G, and GRNIR represents the average value of the red light band, green light band and near - infrared light band.

[0012] Preferably, determining the soil salt crust thickness of the target detection area according to the first salt crust thickness and the second salt crust thickness includes:<J Determine the average value of the first salt crust thickness and the second salt crust thickness, and set the average value as the soil salt crust thickness of the target detection area.

[0013] The present invention also discloses a soil salt crust detection system for coastal areas, which is used to apply the above - mentioned soil salt crust detection method for coastal areas, and includes: A salt crust area determination module, configured to obtain the soil surface albedo of the target detection area, and determine whether the target detection area is a high - coverage area 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 by using a core sampler if it is determined that the target detection area is a high-coverage area of soil salt crust; The porosity data processing module is configured to scan the soil salt crust samples by using a CT scanner to obtain the vertical distribution data of the porosity of the soil salt crust samples, and determine the first salt crust thickness of the soil salt crust samples according to the vertical distribution data of the porosity; The spectral data processing module is configured to detect the soil salt crust samples by using a spectrometer to obtain the vertical distribution data of the spectrum of the soil salt crust samples, and determine the second salt crust thickness of the soil salt crust samples according to the vertical distribution data of the spectrum; The salt crust thickness determination module is configured to determine the soil salt crust thickness of the target detection area according to the first salt crust thickness and the second salt crust thickness.

[0014] Compared with the prior art, the beneficial effect of the present invention is that by obtaining the soil surface albedo to determine whether it is a high-coverage area of soil salt crust, this method can quickly make a preliminary judgment under natural field conditions. Compared with traditional methods such as point-by-point sampling analysis, it can more efficiently screen out the areas that need to be detected in detail, saving a large amount of manpower and time costs and improving the detection efficiency.

[0015] The CT scanner is used to scan the soil salt crust samples to obtain the vertical distribution data of the porosity to determine the first salt crust thickness. CT scanning can clearly present the internal structural details of the samples, which is very effective for analyzing the relationship between the internal pore changes and the salt distribution in the salt crust, so as to accurately judge the thickness of the salt crust at the level of pore change. The spectrometer is used to detect the soil salt crust samples to obtain the vertical distribution data of the spectrum to determine the second salt crust thickness. The spectrometer can detect the absorption and reflection characteristics of different components in the salt crust on the spectrum. Since salts and other substances have different responses on the spectrum, the boundary of the salt crust can be accurately identified according to the vertical distribution of the spectrum and its thickness can be determined. The soil salt crust thickness of the target detection area is determined by integrating the first salt crust thickness and the second salt crust thickness, avoiding the interference and errors that may be caused by a single measurement method. Different measurement methods measure the salt crust thickness from different angles (internal structure and spectral characteristics), verifying and complementing each other, greatly improving the accuracy and reliability of the salt crust thickness measurement. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other accompanying drawings can be obtained according to the provided drawings without creative efforts.

[0017] Figure 1 It is a schematic flowchart of a method for detecting soil salt crust in coastal areas of the present invention.

[0018] Figure 2 It is a functional block diagram of a soil salt crust detection system in coastal areas of the present invention. Detailed implementation manners

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0020] As Figure 1 shown, the present invention provides a method for detecting soil salt crust in coastal areas, including: obtaining the soil surface albedo of the target detection area, and determining whether the target detection area is a high-coverage area of soil salt crust according to the soil surface albedo.

[0021] If it is determined that the target detection area is a high-coverage area of soil salt crust, a number of soil salt crust samples are collected using a core sampler.

[0022] The soil salt crust samples are scanned using a CT scanner to obtain the vertical distribution data of the porosity of the soil salt crust samples, and the first salt crust thickness of the soil salt crust samples is determined according to the vertical distribution data of the porosity.

[0023] The soil salt crust samples are detected using a spectrometer to obtain the vertical distribution data of the spectrum of the soil salt crust samples, and the second salt crust thickness of the soil salt crust samples is determined according to the vertical distribution data of the spectrum.

[0024] The soil salt crust thickness of the target detection area is determined according to the first salt crust thickness and the second salt crust thickness.

[0025] By combining the vertical distribution data of porosity and the vertical distribution data of spectra, the present invention can more accurately evaluate the thickness of soil salt crusts, improving the detection accuracy. At the same time, the use of modern instruments such as CT scanners and spectrometers for detection improves the detection efficiency and accuracy, providing strong technical support for the research and management of soil salt crusts in coastal areas.

[0026] In some embodiments of the present application, determining whether the target detection area is a high soil salt crust coverage area according to the soil surface albedo includes: obtaining the soil surface water content of the target detection area and the surface area of the target detection area, and determining the albedo of the salt-free soil surface of the salt-free soil based on the soil surface water 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 albedo of the salt-free soil surface; determining the salt crust coverage ratio of the target detection area according to the salt crust coverage area; and determining whether the target detection area is a high soil salt crust coverage area based on the salt crust coverage ratio.

[0027] 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 precisely. First, by obtaining the soil surface water content and the surface area of the target detection area, the albedo of the salt-free soil surface of the salt-free soil can be calculated, which provides basic data for the subsequent calculation of the salt crust coverage area. Then, by combining the soil surface albedo and the albedo of the salt-free soil surface, the salt crust coverage area of the target detection area can be accurately determined, which is of great significance for evaluating the distribution of salt crusts. Further, calculating the salt crust coverage ratio according to the salt crust coverage area can intuitively reflect the salt crust coverage degree of the target detection area. Finally, based on the salt crust coverage ratio, it can be judged whether the target detection area is a high soil salt crust coverage area.

[0028] In this embodiment, the soil surface albedo can be obtained in the following ways: (1) Laboratory measurement Principle: Under controllable conditions, a light source is used to simulate solar radiation, and the reflectance of the soil sample in the target detection area is measured.

[0029] Steps: Collect soil samples to ensure a flat surface. Use a spectrometer or spectrophotometer to measure the reflectance of the soil surface in specific bands (such as visible light, near-infrared).

[0030] Calculate the albedo: Albedo = reflected radiation flux / incident radiation flux.

[0031] Optional: Spectrometer: such as ultraviolet-visible-near-infrared spectrometer (UV-VIS-NIR), which can measure multi-band reflectance. Spectrophotometer: used for single-band or multi-band reflectance measurement. Integrating sphere: used to uniformly illuminate the sample and collect the reflected light to improve the measurement accuracy.

[0032] (2) Field measurement Principle: In the natural environment, a portable instrument is used to directly measure the reflectance of the soil surface.

[0033] Steps: Select a representative plot to ensure that the soil surface is flat and unobstructed. Use a portable spectrometer or albedometer to measure the reflectance of the soil surface in the vertical direction. Record environmental parameters such as the solar altitude angle and weather conditions for subsequent correction.

[0034] Optional: Portable spectrometer: such as ASD FieldSpect®, which can quickly measure multi-band reflectance. Albedometer: specifically used for measuring surface albedo, usually including multiple bands (such as visible light, near infrared). Sun photometer: used for measuring the incident solar radiation and calculating the albedo in combination with the reflectance.

[0035] In some embodiments of the present application, obtaining the water content of the soil surface layer in the target detection area and determining the albedo of the salt-free soil surface based on the water content of the soil surface layer includes: collecting a salt-free soil surface layer sample in the target detection area and using the direct measurement method to determine the water content of the soil surface layer in the target detection area; determining the albedo of the salt-free soil surface according to the range of the water content of the soil surface layer; wherein, if the water content of the soil surface layer < 0.1, the albedo of the salt-free soil surface is 0.25; if 0.1 ≤ the water content of the soil surface layer < 0.25, the albedo of the salt-free soil surface is 0.35 - the water content of the soil surface layer; if the water content of the soil surface layer ≥ 0.25, the albedo of the salt-free soil surface is 0.1.

[0036] In this embodiment, the water content of the soil surface layer can be obtained in the following manner: The direct measurement method is to collect soil samples and directly measure their mass or volume water content, including the drying method and the alcohol combustion method.

[0037] Drying method: Collect soil surface layer samples (usually 0 - 5 cm or 0 - 10 cm). Weigh the mass of the wet soil. Put the sample into an oven (105°C) and dry it to a constant weight, then weigh the mass of the dry soil. Calculate the water content: Water content (%) = (mass of wet soil - mass of dry soil) / mass of dry soil × 100%.

[0038] Alcohol combustion method: Collect soil samples and weigh the mass of the wet soil. Add alcohol and burn it, and then weigh the mass of the dry soil after the water has evaporated. Calculate the water content.

[0039] 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 albedo of the salt - free soil surface, the salt crust coverage area is determined by the following formula: ; where A SC represents the salt crust coverage area, A C represents the surface area of the target detection area, α SC represents the soil surface albedo, α C represents the albedo of the salt - free soil surface, and a represents the fitting coefficient.

[0040] It can be understood that this solution can accurately and quickly evaluate the coverage of soil salt crust in coastal areas, providing a scientific basis for the monitoring and management of soil salinization. Compared with traditional soil salt crust detection methods, this method not only improves the detection efficiency but also reduces the human and material costs. At the same time, by introducing the fitting coefficient a, the accuracy of calculating the salt crust coverage area is further improved, making the detection results more reliable.

[0041] In some embodiments of the present application, determining the first salt crust thickness of the soil salt crust sample according to the vertical distribution data of porosity includes: based on the vertical distribution data of porosity, determining the porosity change rate between the porosity value of each layer and the porosity value of the adjacent lower layer, determining the difference ratio of the adjacent porosity change rates, determining the maximum value of the difference ratio, obtaining the layer number of the soil salt crust sample corresponding to the maximum value of the difference ratio, and setting the depth corresponding to this layer number as the first salt crust thickness of the soil salt crust sample.

[0042] It can be understood that this solution can accurately quantify the thickness of the soil salt crust, providing key data support for in - depth research on the salt crust. Traditional methods often rely on manual observation and empirical judgment and are difficult to accurately measure the thickness of the salt crust. However, this technical solution realizes an objective and accurate evaluation of the salt crust thickness through the analysis of the vertical distribution data of porosity. This not only improves the scientific nature of soil salinization research but also provides a more accurate reference basis for the treatment of soil salinization.

[0043] For example: the porosity data from top to bottom is (2, 3, 4, 5, 6, 7, 8, 8, 8, 8), the corresponding porosity change rate of each layer is - 50.00, - 33.33, - 25.00, - 20.00, - 16.67, - 14.29, 0.00, 0.00, 0.00 (%), and the maximum value of the difference ratio of the adjacent porosity change rates is 1, that is, the depth corresponding to the sixth layer is the first salt crust thickness of the soil salt crust sample.

[0044] In some embodiments of the present application, determining the first salt crust thickness of the soil salt crust sample according to the vertical porosity distribution data includes: setting the thickness of the soil salt crust sample as h, and setting the number of layers of the soil salt crust sample in the order from top to bottom; calculating the porosity mean value of layers 1 to n and the porosity mean value of layers n + 1 to h; if the porosity mean values of layers 1 to 2, 1 to 3,..., 1 to n are different, and the porosity mean values of layers n + 1 to h, n + 2 to h,..., h - 1 to h are the same, then determining the depth corresponding to layer n as the first salt crust thickness of the soil salt crust sample.

[0045] It can be understood that this solution can quickly and accurately determine the thickness of the soil salt crust in the actual field environment, greatly improving the detection efficiency. It not only saves manpower and material resources, but also improves the accuracy and reliability of the measurement.

[0046] In some embodiments of the present application, determining the second salt crust thickness of the soil salt crust sample according to the vertical spectral distribution data includes: determining the soil crust index of each layer of the soil salt crust sample according to the vertical spectral distribution data; determining the soil crust index setting range according to the soil crust index of the salt - free soil; judging and setting whether the soil crust index of each layer of the soil salt crust sample is within the soil crust index setting range in the order from top to bottom. If it is within the range, then determining the depth of the upper layer corresponding to the layer number when the soil crust index of the soil salt crust sample is within the soil crust index setting range as the second salt crust thickness of the soil salt crust sample.

[0047] In some embodiments of the present application, when determining the soil crust index of each layer of the soil salt crust sample according to the vertical spectral distribution data, the soil crust index is determined according to the following formula: ; where SC represents the soil crust index, R represents the reflectance in the red light band, G represents the reflectance in the green light band, L represents the correction coefficient of the difference between R and G, and GRNIR represents the average value of the red light band, green light band and near - infrared light band.

[0048] In this embodiment, using the spectral vertical distribution data, the soil crust index of each layer of soil salt crust sample is calculated. The soil crust index is an index for evaluating the formation degree of soil surface salt crust by analyzing the spectral characteristics of soil samples. The normal range of the soil crust index of salt-free soil is determined. This range is set based on the spectral characteristics of salt-free soil to distinguish between soils with salt crust and those without salt crust. Starting from the top layer of the soil sample, layer by layer downward, it is judged whether the soil crust index of each layer falls within the set range of the soil crust index of salt-free soil. This judgment process is carried out by comparing the soil crust index of each layer with the range of the soil crust index of salt-free soil. If the soil crust index of a certain 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 within the depth range from the soil surface to the layer above, the soil crust is a salt crust.

[0049] In some embodiments of the present application, determining the soil salt crust thickness of the target detection area according to the first salt crust thickness and the second salt crust thickness includes: Determine the average value of the first salt crust thickness and the second salt crust thickness, and set the average value as the soil salt crust thickness of the target detection area.

[0050] As Figure 2 shown, the present invention also discloses a soil salt crust detection system in coastal areas for applying the above-mentioned soil salt crust detection method in coastal areas, including: a salt crust area determination module configured to obtain the soil surface albedo of the target detection area and determine whether the target detection area is a high-coverage area of soil salt crust according to the soil surface albedo.

[0051] A soil salt crust sampling module configured to, if it is determined that the target detection area is a high-coverage area of soil salt crust, collect several groups of soil salt crust samples using a core sampler.

[0052] A porosity data processing module configured to scan the soil salt crust samples using a CT scanner to obtain the vertical distribution data of the porosity of the soil salt crust samples, and determine the first salt crust thickness of the soil salt crust samples according to the vertical distribution data of the porosity.

[0053] A spectral data processing module configured to detect the soil salt crust samples using a spectrometer to obtain the spectral vertical distribution data of the soil salt crust samples, and determine the second salt crust thickness of the soil salt crust samples according to the spectral vertical distribution data.

[0054] A salt crust thickness determination module configured to determine the soil salt crust thickness of the target detection area according to the first salt crust thickness and the second salt crust thickness.

[0055] The present invention can accurately and quickly determine the thickness of soil salt crust in coastal areas, improving the detection efficiency. At the same time, by combining multiple detection means, such as CT scanning and spectrometer detection, the physical and chemical properties of soil salt crust can be comprehensively obtained, providing a scientific basis for subsequent soil management and improvement. In addition, the detection system also has the advantages of simple operation and wide application range, and is suitable for the detection needs of different types of coastal soil salt crust.

[0056] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0057] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one or more flows and / or Figure 1 blocks or multiple blocks.

[0058] These computer program instructions can 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 generate a manufactured article including instruction means, and the instruction means implement the functions specified in Figure 1 one or more flows and / or Figure 1 blocks or multiple blocks.

[0059] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one or more flows and / or Figure 1 blocks or multiple blocks.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or make equivalent substitutions, and any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for detecting soil salt crust in coastal areas, characterized in that, Including: Obtain the soil surface albedo of the target detection area, and determine whether the target detection area is a high soil salt crust coverage area according to the soil surface albedo; If it is determined that the target detection area is a high soil salt crust coverage area, use a core sampler to collect several groups of soil salt crust samples; Use a CT scanner to scan the soil salt crust samples to obtain the vertical distribution data of the porosity of the soil salt crust samples, and determine the first salt crust thickness of the soil salt crust samples according to the vertical distribution data of the porosity; Use a spectrometer to detect the soil salt crust samples to obtain the vertical distribution data of the spectrum of the soil salt crust samples, and determine the second salt crust thickness of the soil salt crust samples according to the vertical distribution data of the spectrum; Determine the soil salt crust thickness of the target detection area 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 a high soil salt crust coverage area according to the soil surface albedo includes: Obtain the soil surface moisture content of the target detection area and the surface area of the target detection area, and determine the albedo of the salt-free soil surface of the salt-free soil based on the soil surface moisture content; Based on the surface area of the target detection area, determine the salt crust coverage area of the target detection area according to the soil surface albedo and the albedo of the salt-free soil surface; Determine the salt crust coverage ratio of the target detection area according to the salt crust coverage area; Based on the salt crust coverage ratio, determine whether the target detection area is a high soil salt crust coverage area.

3. The method for detecting soil salt crust in coastal areas according to claim 2, characterized in that, Obtain the soil surface moisture content of the target detection area, and determine the albedo of the salt-free soil surface of the salt-free soil based on the soil surface moisture content, including: Collect a salt-free soil surface sample of the target detection area, and use the direct measurement method to determine the soil surface moisture content of the target detection area; Determine the albedo of the salt-free soil surface of the salt-free soil according to the range of the soil surface moisture content; Wherein, if the soil surface moisture content < 0.1, the albedo of the salt-free soil surface is 0.25; If 0.1 ≤ soil surface moisture content < 0.25, the albedo of the salt-free soil surface is 0.35 - soil surface moisture content; If the soil surface moisture content ≥ 0.25, the albedo of the salt-free soil surface 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 according to the soil surface albedo and the albedo of the salt-free soil surface based on the surface area of the target detection area, the salt crust coverage area is determined by the following formula: ； Among them, A SC represents the salt crust coverage area, and A C represents the surface area of the target detection area. α SC represents the soil surface albedo, and α C represents the albedo of the salt-free soil surface. a represents the fitting coefficient.

5. The method for detecting soil salt crust in coastal areas according to claim 1, characterized in that, Determining the first salt crust thickness of the soil salt crust samples according to the vertical distribution data of the porosity includes: Based on the vertical distribution data of the porosity, determine the porosity change rate between the porosity values of each layer and the porosity values of the adjacent lower layer, determine the difference ratio of the adjacent porosity change rates, determine the maximum value of the difference ratio, obtain the layer number of the soil salt crust samples corresponding to the maximum value of the difference ratio, and set the depth corresponding to the layer number as the first salt crust thickness of the soil salt crust samples.

6. The method for detecting soil salt crust in coastal areas according to claim 1, characterized in that, Determining the first salt crust thickness of the soil salt crust samples according to the vertical distribution data of the porosity includes: Set the thickness of the soil salt crust samples as h, and set the layer number of the soil salt crust samples in the order from top to bottom; Calculate the average porosity of the 1st to nth layers and the average porosity of the (n + 1)th to hth layers; If the average porosity of the 1st to 2nd layers, the 1st to 3rd layers,..., the 1st to nth layers are different, and the average porosity of the (n + 1)th to hth layers, the (n + 2)th to hth layers,..., the (h - 1)th to hth layers are the same, then determine the depth corresponding to the nth layer as the first salt crust thickness of the soil salt crust sample.

7. The method for detecting soil salt crust in coastal areas according to claim 1, characterized in that, Determine the second salt crust thickness of the soil salt crust sample according to the spectral vertical distribution data, including: Determine the soil crust index of each layer of the soil salt crust sample according to the spectral vertical distribution data; Determine the soil crust index setting range according to the soil crust index of the salt-free soil; Judge and set whether the soil crust index of each layer of the soil salt crust sample is within the soil crust index setting range in the order from top to bottom. If it is within the range, determine the depth of the upper layer corresponding to the layer number when the soil crust index of the soil salt crust sample is within the soil crust index setting range as 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 the soil salt crust sample according to 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 reflectance in the red light band, G represents the reflectance in the green light band, L represents the correction coefficient of the difference between R and G, and GRNIR represents the average value of the red light band, the green light band and the near-infrared band.

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

10. A soil salt crust detection system for a coastal area, which is used to apply the soil salt crust detection method for a coastal area according to any one of claims 1-9, and is characterized in that, Including: A salt crust area determination module, configured to obtain the soil surface albedo of the target detection area, and determine whether the target detection area is a high-coverage area of soil salt crust according to the soil surface albedo; A soil salt crust sampling module, configured to collect several groups of soil salt crust samples by using a core sampler if it is determined that the target detection area is a high-coverage area of soil salt crust; A porosity data processing module, configured to scan the soil salt crust sample by using a CT scanner to obtain the porosity vertical distribution data of the soil salt crust sample, and determine the first salt crust thickness of the soil salt crust sample according to the porosity vertical distribution data; A spectral data processing module, configured to detect the soil salt crust sample by using a spectrometer to obtain the 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; A salt crust thickness determination module, configured to determine the soil salt crust thickness of the target detection area according to the first salt crust thickness and the second salt crust thickness.

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