Methods, systems and storage media for soil testing in areas occupying arable land

Abstract

This invention provides a method, system, and storage medium for soil testing in areas of arable land occupied by construction, belonging to the field of soil testing technology. The method includes: S1: acquiring boundary data and secondary land use category data of the arable land occupied by construction to divide the target testing area into multiple soil testing units; S2: determining the number and location of sampling points based on the area of ​​each soil testing unit, and collecting soil samples according to the sampling points; S3: performing basic testing on the soil samples, and supplementary testing based on pollution risk information and barrier factor information of the corresponding soil testing unit to obtain sample testing results; S4: summarizing the sample testing results according to the soil testing units to generate zonal soil testing results for the target testing area. This invention provides a basis for the classification, disposal, and reuse of soil to be stripped through zonal sampling and differentiated testing.

Description

Technical Field

[0001] This invention relates to the field of soil testing technology, and more specifically to a method, system, and storage medium for soil testing in areas where construction has occupied arable land. Background Technology

[0002] When construction projects occupy arable land, the topsoil within the occupied area is not ordinary construction waste, but rather topsoil resources with reuse value. This portion of soil retains relatively intact land use boundaries, soil layer conditions, and physicochemical properties before construction disturbance. Subsequent investigations and evaluations typically determine whether to strip the topsoil, how to classify and store it, and what suitable reuse destination it should be for. Therefore, conducting soil testing in the occupied arable land area before topsoil stripping is a fundamental step in developing a stripping and utilization plan and a soil disposal plan.

[0003] Current soil testing methods typically involve setting up sampling points according to the surveyed area, and then performing uniform testing on the samples. This approach is feasible for general farmland quality surveys, but scenarios involving construction occupying arable land have stronger boundary and destination constraints. The same construction occupation area may simultaneously contain different arable land types such as paddy fields, irrigated land, and dry land, with differences in utilization status, soil layer thickness, soil texture, and fertility base. If sampling points are only set up according to the overall area, it is easy to mix soils of different types as the same testing object, making it difficult for the test results to support subsequent soil classification, storage, and reuse determination.

[0004] Furthermore, the topsoil to be stripped may be affected by historical land use activities, potential pollution sources in the surrounding area, or soil barrier factors. The pollution risk here does not stem from any construction activity yet, but rather is used to determine whether this portion of the soil can be used for different reuse pathways such as farmland improvement, high-standard farmland construction, reclamation, or greening. If only a fixed testing checklist is used during testing, without supplementing the testing with previous pollution investigation data, pollution history, potential pollution sources, and barrier factor types, soil unsuitable for reuse may be misclassified as usable soil, or soil with reuse value may lack corresponding quality data.

[0005] Therefore, the technical problem that the existing technology urgently needs to solve is: before the construction of cultivated land areas to be stripped and reused, how to form a soil testing method with clear zoning, reasonable sampling points, and test items that can be adjusted according to changes in pollution risk and barrier factors, so as to support the subsequent classification, disposal and reuse destination determination of topsoil. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for soil testing in areas where construction occupies arable land, so as to at least solve the problems of insufficient zoning sampling and weak targeting of testing items in existing testing methods.

[0007] To achieve the above objectives, the first aspect of the present invention provides a method for soil testing in areas where construction has occupied arable land. The method includes: S1: acquiring boundary data of the area where construction has occupied arable land and secondary land use category data of arable land to divide the target testing area into multiple soil testing units; S2: determining the number and location of sampling points according to the area of ​​each soil testing unit, and collecting soil samples according to the sampling points; S3: performing basic testing on the soil samples, and performing supplementary testing based on pollution risk information and barrier factor information of the corresponding soil testing unit to obtain sample testing results; S4: summarizing the sample testing results according to the soil testing units to generate zonal soil testing results for the target testing area.

[0008] A second aspect of the present invention provides a soil testing system for construction-occupied cultivated land areas. The system is used to execute the aforementioned soil testing method for construction-occupied cultivated land areas. The system includes: a division module for acquiring boundary data and secondary land use category data of the construction-occupied cultivated land area to divide the target testing area into multiple soil testing units; a sampling module for determining the number and location of sampling points based on the area of ​​each soil testing unit, and collecting soil samples according to the sampling points; a testing module for performing basic testing on the soil samples, and supplementary testing based on pollution risk information and barrier factor information of the corresponding soil testing unit, to obtain sample testing results; and an output module for summarizing the sample testing results according to the soil testing units to generate zonal soil testing results for the target testing area.

[0009] A third aspect of the present invention provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the above-described method for detecting soil in areas of cultivated land occupied by construction.

[0010] Through the above technical solution, the present invention divides soil testing units according to the construction occupation boundary and the secondary land category of cultivated land, and sets sampling points according to the unit area. This avoids mixed sampling of soils of different land categories and improves the representativeness of the samples for each testing unit. On the basis of basic testing, corresponding testing items are added according to pollution risk and obstacle factors to reduce the omission of pollutants or soil obstacles caused by fixed testing items. Then, the sample testing results are summarized according to soil testing units to form zonal soil testing results corresponding to the land category range and sampling location, providing a testing basis for the quality judgment, classification and disposal, and subsequent reuse planning of the topsoil to be stripped.

[0011] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0012] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of the steps of a method for soil testing in areas of arable land occupied by construction, provided by one embodiment of the present invention; Figure 2 This is a schematic diagram of a soil testing unit and sampling points in an area of ​​cultivated land occupied by construction, provided by one embodiment of the present invention; Figure 3 This is a schematic diagram of hilly farmland sampling points based on contour line zoning and slope runoff relationship provided by one embodiment of the present invention; Figure 4 This is a system structure diagram of a soil detection system for construction-occupied arable land areas provided by one embodiment of the present invention. Detailed Implementation

[0013] like Figure 1 As shown, this invention provides a method for soil testing in areas where construction has occupied arable land. The method includes: Step S1: Obtain the boundary data of the construction-occupied cultivated land area and the secondary land category data of cultivated land to divide the target detection area into multiple soil detection units.

[0014] S2: Determine the number and location of sampling points based on the area of ​​each soil testing unit, and collect soil samples according to the sampling points.

[0015] S3: Perform basic testing on the soil sample, and perform supplementary testing based on the pollution risk information and obstacle factor information of the corresponding soil testing unit to obtain the sample testing results.

[0016] S4: Summarize the sample test results according to the soil testing unit to generate the zoned soil test results for the target testing area.

[0017] Specifically, in step S1, the boundary data of the construction-occupied cultivated land area and the secondary land use category map data of cultivated land are obtained to divide the target detection area into multiple soil detection units. This includes: obtaining the boundary data of the construction-occupied cultivated land area, wherein the boundary data includes the coordinates of the construction-occupied boundary and the closed boundary formed by the construction-occupied boundary coordinates; obtaining the secondary land use category map data of cultivated land that spatially overlaps with the closed boundary, wherein the secondary land use category map data includes the cultivated land map boundary, cultivated land use category type, and map area; and dividing the closed boundary... The cultivated land patches are spatially superimposed with the boundaries of the cultivated land patches, and the cultivated land patches falling within the closed boundaries are cropped to obtain cultivated land detection patches located within the target detection area; the cultivated land detection patches are classified according to their cultivated land type, and cultivated land detection patches with the same cultivated land type are assigned to the same soil detection unit, while cultivated land detection patches with different cultivated land types are assigned to different soil detection units; the cropped areas of each cultivated land detection patch belonging to the same soil detection unit are summed to determine the area of ​​the corresponding soil detection unit.

[0018] In this embodiment of the invention, the boundary data uses the construction and occupation boundary coordinates under a unified coordinate system, and connects them according to the arrangement order of the coordinate points to form a closed boundary, which defines the target detection area. The secondary land use category data of cultivated land is derived from the land use status survey results corresponding to the target area, and includes at least the spatial boundary of each cultivated land category, the cultivated land type, and the original area of ​​each category. The cultivated land type includes paddy fields, irrigated land, and dry land.

[0019] After obtaining the above data, the closed boundary is spatially overlaid with the boundaries of each cultivated land patch. For cultivated land patches completely located within the closed boundary, their original boundaries are retained; for cultivated land patches only partially located within the closed boundary, the overlapping area between the closed boundary and the cultivated land patch is extracted as the cropped cultivated land detection patch; patches located outside the closed boundary are excluded. Thus, all cultivated land detection patches located within the target detection area are obtained.

[0020] Further coarse-grained classification of farmland monitoring patches was performed according to farmland land type. Farmland monitoring patches with the same farmland land type were assigned to the same soil monitoring unit, while farmland monitoring patches with different farmland land types were assigned to different soil monitoring units. A soil monitoring unit is used to characterize a group of monitoring areas with the same farmland land type attribute. It includes both adjacent farmland monitoring patches and farmland monitoring patches that are spatially discontinuous due to separation by roads, ditches, water bodies, or non-farmland patches. The area of ​​the corresponding soil monitoring unit is obtained by summing the cropped areas of all farmland monitoring patches belonging to the same soil monitoring unit.

[0021] For example, within the target detection area, there are two separate paddy field patches and one irrigated land patch. The two paddy field patches are classified into paddy field soil detection units according to the same cultivated land type, and in subsequent steps, they are respectively divided into contiguous paddy field sampling areas A and B based on spatial continuity. The irrigated land patch is classified into irrigated land soil detection units, forming a corresponding contiguous irrigated land sampling area C. Finally, the area of ​​the corresponding unit is determined based on the actual area of ​​the cropped patches within each soil detection unit, providing an area basis for determining the number and location of subsequent sampling points. The above land type and unit division method are used to illustrate this embodiment and do not constitute a limitation on specific land type combinations or the number of units.

[0022] Specifically, in step S2, determining the number and location of sampling points based on the area of ​​each soil testing unit includes: determining the total number of sampling points for each soil testing unit based on its area and a preset area threshold; identifying the spatial continuity between farmland detection patches within the soil testing unit, identifying one or more spatially continuous farmland detection patches as the same contiguous sampling area, thus obtaining one or more contiguous sampling areas corresponding to the soil testing unit; allocating the total number of sampling points to each contiguous sampling area based on the proportion of the area of ​​each contiguous sampling area to the area of ​​the soil testing unit and the spatial separation relationship between the contiguous sampling areas, thus obtaining the number of sampling points corresponding to each contiguous sampling area; generating sampling points within each contiguous sampling area based on the boundary of each contiguous sampling area and the corresponding number of sampling points, and ensuring that the sampling points are located within the boundary range of the corresponding soil testing unit. In this embodiment of the invention, the soil testing unit is used to uniformly organize the testing tasks under the same arable land type, and the contiguous sampling area is used to constrain the specific sampling space. For arable land testing patches that are spatially discontinuous within the same soil testing unit, the total number of sampling points is first determined based on the area of ​​the soil testing unit, and then one or more contiguous sampling areas are formed according to the spatial continuity relationship. The total number of sampling points is then allocated to each contiguous sampling area to avoid concentrating sampling points in a single contiguous area within the soil testing unit.

[0023] The continuity between farmland monitoring patches within each soil testing unit is identified based on their spatial boundaries. Farmland monitoring patches with contiguous boundaries and not separated by roads, ditches, water bodies, or non-farmland patches are grouped into the same contiguous sampling area. Farmland monitoring patches with non-contiguous boundaries, or those that are close in distance but separated by the aforementioned features, form separate contiguous sampling areas. Thus, one or more spatially independent contiguous sampling areas are formed within the same soil testing unit, providing a boundary basis for the spatial allocation of the total number of sampling points.

[0024] The actual area of ​​each soil testing unit is calculated, and the total number of sampling points is determined based on the area of ​​the soil testing units. In this embodiment, the preset area threshold is set to 5 hm².2 Area not greater than 5 hm 2 Each soil testing unit should have one sampling point. The area should be greater than 5 hectares. 2 At that time, for every additional 5 hm of the excess portion 2 An additional sampling point is added to each area interval; portions less than a complete area interval are treated as a single area interval. For example, an area of ​​3 hm²... 2 The soil testing unit has one sampling point with an area of ​​8 hm². 2 The soil testing unit was set up with two sampling points, covering an area of ​​12 hm². 2 The soil testing unit is equipped with three sampling points.

[0025] After determining the total number of sampling points, these points are allocated to contiguous sampling areas within the corresponding soil testing units. When the total number of sampling points is not less than the number of contiguous sampling areas, one sampling point is first allocated to each contiguous sampling area. Then, based on the proportion of the area of ​​each contiguous sampling area to the area of ​​the soil testing unit, the remaining sampling points are allocated to each contiguous sampling area. When the total number of sampling points determined based on the area of ​​the soil testing unit is less than the number of contiguous sampling areas, the number of contiguous sampling areas is determined as the adjusted total number of sampling points, and one sampling point is allocated to each contiguous sampling area. Thus, while maintaining a correspondence between the number of sampling points and the area of ​​the soil testing unit, spatially separated farmland areas each have corresponding sampling points.

[0026] Candidate sampling areas are generated within the boundaries of each contiguous sampling area. The boundaries of the contiguous sampling areas are offset inwards by a preset distance to exclude areas near the boundaries that are significantly affected by road drainage, adjacent land types, or construction disturbances. In this embodiment, the offset distance is set to 5 m. Based on the number of sampling points allocated to each contiguous sampling area, the candidate sampling area is divided into a corresponding number of sub-regions of similar size. Within each sub-region, a location farther from the boundary of that sub-region is selected as a sampling point, ensuring that multiple sampling points are distributed dispersedly within the contiguous sampling area. For narrow, elongated contiguous sampling areas whose width is insufficient to form a 5 m offset area, sampling segments are equidistantly divided along their extension direction, and sampling points are placed within each sampling segment.

[0027] After determining the sampling points, verify whether each sampling point is located within the boundary range of the corresponding contiguous sampling area and soil testing unit. For points falling within roads, ditches, water bodies, or non-cultivated land areas, move them along the interior of their respective sub-regions to the nearest valid cultivated land area. After verification, collect soil samples according to each sampling point, and establish a correspondence between the soil samples and their respective soil testing units, contiguous sampling areas, and sampling points. In other embodiments, the preset area threshold, the number of additional points, and the boundary avoidance distance are determined based on the target area area, the degree of fragmentation of the land parcels, and the applicable soil survey requirements, and are not limited to the specific values ​​mentioned above.

[0028] like Figure 2 Taking a construction project in the suburbs of a certain city that plans to occupy cultivated land as an example, the target detection area is divided into paddy field soil detection units, irrigated land soil detection units, and dry land soil detection units based on the spatial overlay results of the construction occupation boundary and the cultivated land secondary land category patches. The paddy field soil detection unit includes contiguous sampling area A and contiguous sampling area B, separated by field ditches and farm roads; the irrigated land soil detection unit includes contiguous sampling area C; and the dry land soil detection unit includes contiguous sampling area D. After trimming, the areas of contiguous sampling areas A, B, C, and D are approximately 10.8 hm². 2 11.6 hm 2 27.4hm 2 and 4.2 hm 2 .

[0029] The area of ​​the paddy field soil testing unit is 22.4 hm². 2 According to 5 hm 2 Five sampling points were determined based on a preset area threshold, and two and three sampling points were allocated to contiguous sampling areas A and B, respectively, according to their area ratios. Six sampling points were set up for the irrigated land soil testing unit, and one sampling point was set up for the dry land soil testing unit, forming a total of twelve sampling points, P1 to P12. Each sampling point was located within its corresponding contiguous sampling area and maintained a distance of no less than 5 m from roads, ditches, and the boundaries of the soil testing unit. After collecting soil samples at the above locations, the test results of each sample were assigned to the corresponding contiguous sampling area and further summarized to the respective soil testing unit, forming the zonal soil testing results for paddy fields, irrigated land, and dry land.

[0030] In another embodiment, for geological conditions with excessive hills, contour data of a contiguous sampling area is obtained. Based on the contour line elevation values ​​and the spacing between adjacent contour lines, the contiguous sampling area is divided into multiple elevation zones. Slope convergence areas are determined based on the curvature direction and spacing changes of the contour lines. The initial sampling points are adjusted according to the coverage status of each elevation zone over the initial sampling points, and additional sampling points are added downstream of the slope convergence areas that traverse multiple elevation zones to obtain the sampling point locations.

[0031] For hilly farmland areas, after determining the initial number of sampling points allocated to contiguous sampling areas, contour lines and corresponding elevation values ​​within the contiguous sampling areas are obtained. In this embodiment, the contour interval is set to 2m. The contour lines are arranged in descending order of elevation, and based on the intersections of the contour lines with the boundaries of the contiguous sampling areas, the contiguous sampling areas are divided into upper slope zone, middle slope zone, and lower slope zone. Further comparison of the spacing and curvature direction of adjacent contour lines identifies areas where the contour line spacing decreases as areas of increasing slope, and areas where contour lines recede towards the higher elevation side as slope convergence zones.

[0032] The initial sampling points, determined and allocated to the corresponding contiguous sampling areas based on the area of ​​the soil testing units, are matched with each slope zoning zone. When the initial sampling points are concentrated in the same slope zoning zone, and no sampling points are set in other slope zoning zones, the initial sampling point closest to the zoning zone boundary is adjusted to the inner area of ​​the uncovered zone. For the slope surface catchment area that runs through the mid-slope zone and extends to the lower slope zone, an additional sampling point is set downstream of the catchment path to detect local differences in the formation of fine particles and soluble substances carried by slope runoff. The adjusted sampling points maintain a avoidance distance of not less than 3m from gullies, field ridges, and land use boundaries. In other embodiments, the contour interval, the number of slope zoning zones, and the avoidance distance are determined based on the elevation difference, slope length, and map scale of the target area; the above values ​​do not constitute a limitation on the protection scope.

[0033] like Figure 3 As shown, the target detection area is located within hilly farmland. Based on contour lines, the corresponding contiguous sampling area is divided into three zones: upper slope, middle slope, and lower slope, with conventional sampling points P1 to P9 set up for each zone. The elevation of the upper slope zone is no less than 480m, the middle slope zone is between 440m and 480m, and the lower slope zone is below 440m. Further, the slope runoff path is identified based on the contour line curvature and spacing. When a runoff path traverses multiple slope zones and forms a runoff area downstream, an additional sampling point P10 is set within the runoff area after the paths converge. All sampling points are located within the project boundary, the boundary of the corresponding soil detection unit, and the boundary of the contiguous sampling area, maintaining a preset avoidance distance from gullies, field ridges, and land use boundaries to account for soil differences at different slope locations and local depositional differences caused by runoff accumulation.

[0034] Specifically, in step S3, the basic testing of the soil sample includes: recording the soil layer thickness at the corresponding sampling point when collecting the soil sample to obtain the soil layer thickness test result; conducting soil texture testing on the soil sample to obtain the texture test result; conducting pH testing on the soil sample to obtain the pH test result; conducting organic matter testing on the soil sample to obtain the organic matter test result; and associating the soil layer thickness test result, the texture test result, the pH test result, and the organic matter test result with the soil testing unit to which the corresponding soil sample belongs to obtain the basic test result.

[0035] Furthermore, the supplementary detection based on the pollution risk information and barrier factor information of the corresponding soil detection unit includes: acquiring the previous soil pollution survey status, pollution history information, potential pollution source information, and potential soil barrier factor type corresponding to the soil detection unit; determining whether to conduct pollution control index detection on the corresponding soil sample based on the previous soil pollution survey status; determining whether to conduct characteristic pollutant detection on the corresponding soil sample based on the pollution history information and the potential pollution source information; determining the specific barrier factor detection items for the corresponding soil sample from the preset barrier factor detection items based on the potential soil barrier factor type, and conducting specific barrier factor detection on the soil sample; wherein, the preset barrier factor detection items include at least one of gravel content, total water-soluble salt, soil bulk density, cation exchange capacity, and available elements; combining the actual pollution control index detection results, characteristic pollutant detection results, and barrier factor specific detection results into supplementary detection results; when none of the supplementary detections are triggered, an empty result set is used as the supplementary detection results.

[0036] In this embodiment of the invention, basic testing is conducted sequentially according to the sampling points to which the soil samples belong, maintaining the correspondence between sampling points, sample numbers, and soil testing units. Soil layer thickness is measured simultaneously during the sample collection phase. Soil is drilled vertically along the sampling points, and the bottom boundary of the cultivated layer is identified based on continuous changes in soil color, structure, root distribution, and compaction. The vertical distance from the ground surface to the bottom boundary of the cultivated layer is measured to obtain the soil layer thickness test results. For soil samples from the same sampling point, plant residues and obvious stones are removed. After natural air drying, crushing, and sieving, soil texture, pH, and organic matter tests are conducted separately.

[0037] Soil texture testing employed particle composition analysis to determine the mass ratio of sand, silt, and clay particles, and identified the corresponding texture type based on a pre-defined soil texture classification standard. pH testing utilized a soil-water mixture method; in this embodiment, the mass-to-volume ratio of soil to deionized water was set to 1:2.5. After thorough shaking and settling, the pH value of the supernatant was measured. Organic matter testing employed the potassium dichromate oxidation method, determining the soil organic matter content based on the amount consumed in the oxidation reaction. These testing methods are standard practices in the field of soil physicochemical testing. Specific reagent preparation, instrument calibration, and operating conditions were performed according to the corresponding testing standards and will not be elaborated further here. The soil layer thickness, texture type, pH value, and organic matter content were correlated with the corresponding sample number and soil testing unit to form the basic test results.

[0038] After completing the basic testing, the previous pollution survey status, pollution history, potential pollution sources, and types of potential soil barrier factors for each soil testing unit are retrieved. The spatial coverage, sampling depth, detection indicators, and data validity period of existing soil pollution survey data are verified. If the existing soil pollution survey data meets the requirements for the current soil testing unit, the corresponding pollutant detection values, applicable limits, and judgment conclusions are extracted to form inherited pollution detection results. If the existing soil pollution survey data does not meet the requirements or relevant data is missing, pollution control indicator detection is triggered. If there is a history of pollution or potential pollution sources, the detection of characteristic pollutants corresponding to the pollution source is triggered. If there are barrier factors such as excessive gravel, salt accumulation, soil compaction, or abnormal nutrient availability, corresponding specific detection items are determined from gravel content, total water-soluble salts, soil bulk density, cation exchange capacity, and available elements.

[0039] The actual inherited pollution detection results and various supplementary detection results are jointly correlated with the basic detection results to the corresponding soil samples; if the supplementary detection items are not triggered, the corresponding reasons for not triggering are recorded.

[0040] Specifically, supplementary tests include: 1) Pollution control indicator detection.

[0041] Specifically, when the soil testing unit corresponding to the previous soil pollution survey status characterization lacks previous soil pollution survey data, the applicable pollution risk control standard is determined based on the land use attribute of the soil testing unit; according to the pollution risk control standard, the pollution control index for the corresponding soil sample is determined from a preset pollution control index library; the content of the pollution control index is tested on the soil sample to obtain the measured content corresponding to each pollution control index; the pH test result of the soil sample is obtained, and the risk screening value or risk control value corresponding to each pollution control index is determined based on the applicable pollution risk control standard and the pH test result; the measured content is compared with the corresponding risk screening value or risk control value to obtain the pollution control index test result.

[0042] In this embodiment of the invention, the preliminary soil pollution survey status is used to characterize whether the corresponding soil testing unit has existing survey data that can cover the unit's range, sampling depth, and the pollutants to be detected. When the aforementioned survey data is not available, or the existing survey data cannot correspond to the current soil testing unit, pollution control indicator detection is triggered. The land use attribute is determined based on the intended reuse area of ​​the soil sample; when intended for farmland restoration, farmland construction, or farmland quality improvement, agricultural land soil pollution risk control standards are matched; when intended for greening or other uses within the construction land area, corresponding construction land risk control standards are matched.

[0043] The pollution control indicator database records land use attributes, pollutant names, sample pretreatment methods, detection methods, and judgment limits. Pollution control indicators for agricultural land include cadmium, mercury, arsenic, lead, chromium, copper, nickel, and zinc. Soil samples are naturally air-dried, have plant residues removed, are ground, and sieved before being digested according to the detection items. Cadmium, lead, chromium, copper, nickel, and zinc are determined using inductively coupled plasma mass spectrometry (ICP-MS) or inductively coupled plasma atomic emission spectrometry (ICP-AES), while mercury and arsenic are determined using atomic fluorescence spectrometry (AES). The above sample digestion, instrument calibration, and quality control are performed according to the corresponding detection standards, and will not be elaborated further here.

[0044] Further, pH test results from basic testing were obtained. For pollution control indicators with judgment limits set according to pH levels, pH was divided into four intervals: not greater than 5.5, greater than 5.5 and not greater than 6.5, greater than 6.5 and not greater than 7.5, and greater than 7.5. Risk screening values ​​and risk control values ​​for the corresponding intervals were extracted from applicable standards. For indicators that do not change with pH, ​​the corresponding limits were directly extracted. The measured content of each pollution control indicator was compared with the corresponding limit item by item. If it did not exceed the risk screening value, it was recorded as not exceeding the limit; if it exceeded the risk screening value, a risk warning mark was set; and if it reached the risk control value, a control mark was set. Finally, the test values, applicable limits, and judgment marks were associated with the sample number, sampling point, and soil testing unit to form the pollution control indicator test results.

[0045] 2) Specific detection of obstacle factors.

[0046] Specifically, based on preliminary survey data, site reconnaissance records, and basic testing results, potential obstacle factors within the soil testing units are identified, and corresponding specific testing items are determined according to the type of obstacle factor. For testing units with a high distribution of gravel on the surface or in the soil, soil samples are graded and sieved, the mass of gravel with a particle size larger than the specified size is weighed, and the gravel content is determined based on the proportion of gravel mass to the total sample mass. For testing units showing signs of salt accumulation, soil leachate is prepared according to the specified soil-to-water ratio, and the total amount of water-soluble salts in the leachate is determined. For testing units exhibiting soil compaction or compaction, undisturbed soil samples are collected at the corresponding sampling points using the ring sampler method, and the soil bulk density is determined based on the dried mass and ring sampler volume. For testing units with insufficient nutrient retention capacity or a deficiency of micronutrients, the cation exchange capacity and corresponding items in available boron, available manganese, available iron, available zinc, available copper, available sulfur, and exchangeable calcium are measured. The above-mentioned screening, extraction, ring sampling and element determination were all carried out in accordance with the corresponding soil testing standards. The reagent preparation and instrument operation are existing testing technologies and will not be described in detail here.

[0047] The measured results of each specialized testing item are associated with the sample number, sampling point, and soil testing unit to form specialized testing results for obstacle factors. Combined with zoning relationships, the specialized testing results within the same testing unit are used to characterize the gravel, salinity, compaction, and nutrient retention characteristics of the soil to be stripped in that area. When planning the subsequent reuse of the soil, these testing results are compared with the requirements of the intended use area for soil texture, salinity, bulk density, and nutrient conditions. This helps identify soils suitable for direct use, treatment, or unsuitable for agricultural use, providing a basis for the classification, storage, and reuse determination of the soil to be stripped.

[0048] 3) Detection of characteristic pollutants.

[0049] Specifically, when the soil testing unit corresponding to the pollution history information characterization has a history of pollution, or when the soil testing unit corresponding to the potential pollution source information characterization is located within the influence range of a potential pollution source, the corresponding pollution source type is determined; based on the pollution source type, the corresponding characteristic pollutant testing item is matched from a preset characteristic pollutant item library; the content of the characteristic pollutant testing item is tested on the soil sample to obtain the measured content of the characteristic pollutant; the measured content of the characteristic pollutant is compared with the corresponding pollution risk judgment limit to obtain the characteristic pollutant testing result.

[0050] In this embodiment of the invention, the pollution source type is determined based on historical pollution information and potential pollution source information, and a correspondence is established between the pollution source type and the characteristic pollutant detection items. Historical pollution information includes historical production activities, types of raw and auxiliary materials, pollution accident records, and existing detection records; potential pollution source information includes the location of the pollution source, the type of pollution source, the emission location, and the direction of surface runoff. When the soil testing unit has historical pollution records, or is located within the downstream influence range of a potential pollution source, the characteristic pollutant detection items are determined according to the corresponding pollution source type.

[0051] In this embodiment, taking a soil testing unit adjacent to a metal processing and surface treatment site as an example, cadmium, chromium, lead, nickel, copper, and zinc were identified as characteristic pollutants. Soil samples were collected from the 0-20cm soil layer at each sampling point. Five sub-points were selected within a 5m radius around each sampling point, and equal-mass soil samples were collected from each sub-point. After mixing, at least 1kg was retained as the test sample. The test sample was air-dried, and after removing plant residues and obvious gravel, it was passed through a 2mm sieve. A portion of the sample was then ground until it passed through a 0.15mm sieve. 0.2000g of the ground sample was weighed, and 6mL of nitric acid, 2mL of hydrochloric acid, and 2mL of hydrofluoric acid were added for microwave digestion. After digestion, the acid was removed, and the volume was adjusted to 50mL. The measured content of each characteristic pollutant was determined by inductively coupled plasma mass spectrometry. Blank samples, parallel samples, and spiked samples were prepared simultaneously for each batch of samples. The relative deviation of the parallel samples was no more than 20%, and the spiked recovery rate was controlled between 80% and 120%. If the requirements were not met, the sample pretreatment and testing were repeated.

[0052] Based on the secondary land use category of the arable land to which the soil sample belongs and the intended reuse area, corresponding pollution risk assessment limits are determined, and the measured content of each characteristic pollutant is compared with the assessment limits item by item. If all tested items do not exceed the corresponding limits, it is recorded as meeting the corresponding agricultural reuse conditions. If any tested item exceeds the corresponding limit, the exceeding item and the exceeding sampling point are marked, and the corresponding soil testing unit is separated from the direct agricultural reuse destination to avoid mixing with other soils that meet the requirements after stripping and transportation. In other embodiments, oil storage and transportation sources correspond to the detection of petroleum hydrocarbons and polycyclic aromatic hydrocarbons, and pesticide storage sources correspond to the detection of corresponding pesticide residues. The specific items are determined according to the type of pollution source and are not limited to the aforementioned metallic pollutants.

[0053] When pollution control indicator detection, characteristic pollutant detection, and barrier factor-specific detection are not triggered, the empty set is used as the supplementary detection result. The empty set is used to indicate that there are no supplementary detection items to be performed for the corresponding soil detection unit, rather than that the supplementary detection data is missing.

[0054] After obtaining the sample test results, the continuity of pH, organic matter, total water-soluble salts, and particle size distribution at adjacent sampling points within the same soil testing unit is verified. If the change in any indicator at adjacent points exceeds the corresponding mutation threshold, and the change in at least one other indicator at adjacent points also exceeds its corresponding mutation threshold, the corresponding section is identified as a suspected soil transition zone. In this embodiment, the pH mutation threshold is set to 0.8, the organic matter change threshold is set to 5 g / kg, and the total water-soluble salt change threshold is set to 0.5 g / kg. A verification sampling point is set on each side of the suspected soil transition zone, and a validation sampling point is set at the center of the transition zone, and the corresponding abnormal indicators are re-tested. If the validation results still meet the mutation conditions, the original soil testing unit is divided into two sub-units based on the spatial location between the verification sampling points, and sample test results are generated separately for each sub-unit, avoiding the masking of local soil differences within the same testing unit by the overall summary results.

[0055] Specifically, in step S4, the sample test results are summarized according to the soil testing units to generate the zonal soil test results for the target testing area. This includes: using the soil testing unit as the primary index and the contiguous sampling area as the secondary index, collecting soil samples and their test results belonging to the same contiguous sampling area, and then summarizing the test records of each contiguous sampling area to its respective soil testing unit; associating the sample test results with the sampling location of each soil sample to the sampling location within the corresponding soil testing unit according to the sampling point location of each soil sample; organizing the basic test results and supplementary test results within the same soil testing unit according to the test item type to obtain the unit test record; associating the unit test record with the boundary and cultivated land type of the corresponding soil testing unit to generate the zonal soil test results for the target testing area; wherein, the zonal soil test results include the soil testing unit boundary, cultivated land type, contiguous sampling area boundary, contiguous sampling area number, sampling point location, soil sample, test item, test value, and out-of-limit item marker.

[0056] In this embodiment of the invention, after completing the basic and supplementary tests on each soil sample, the soil testing unit number is used as the aggregation index to write the sample number, sampling point, and corresponding sample test results into the soil testing unit to which it belongs. The sample test results retain basic test results such as soil layer thickness, soil texture, pH, and organic matter, as well as specific test results for pollution control indicators, characteristic pollutant indicators, and barrier factors. For soil samples that do not trigger a certain supplementary test item, the reason for not triggering is recorded at the corresponding item location, without replacing the test status with a blank value, thereby distinguishing between three situations: no test, test within limits, and test exceeding limits.

[0057] Based on the coordinates of each sampling point, the test results of each group of samples are associated with the actual sampling location within the soil testing unit. In cases where multiple test items are generated from the same sampling point, each test item is associated with the same sample number and sampling point. In cases where the same soil testing unit contains multiple sampling points, the test values ​​of each sampling point are retained separately, and the original test values ​​from different sampling points are not directly merged. Subsequently, the test results are categorized and organized according to basic testing, pollution control indicator testing, characteristic pollutant testing, and barrier factor-specific testing to form unit test records. The unit test record includes at least the soil testing unit number, sample number, sampling point coordinates, test item name, test value, unit of measurement, applicable judgment limit, and testing status.

[0058] Furthermore, each detected value is matched with its corresponding judgment limit. When a detected value exceeds the judgment limit, an "exceeding limit" marker is set for the corresponding detected item, and the sampling point exceeding the limit is recorded; when the detected value does not exceed the judgment limit, it is recorded as not exceeding the limit. In cases where different sampling points within the same soil testing unit exhibit different judgment states, the independent markers of each sampling point are retained, and the soil testing unit is recorded as having a local anomaly area, avoiding the masking of local pollution or obstacle characteristics by a single aggregated value.

[0059] The unit detection records are associated with the spatial boundaries of the corresponding soil detection units and the secondary land use types of cultivated land to form zonal soil detection results. In this embodiment, the zonal soil detection results adopt a combination of spatial layers and attribute records. The spatial layer represents the boundaries of the soil detection units and the sampling points, while the attribute records represent the sample number, detection items, detection values, and out-of-limit items corresponding to each sampling point. Thus, each detection result can be traced back to a specific sampling point and soil detection unit, and provides a zonal detection basis for the subsequent classification and storage of the soil to be stripped, the isolation of abnormal areas, and the determination of its reuse destination.

[0060] After generating the zonal soil testing results, anomaly boundary correction is performed on soil testing units with excessive items or abnormal obstacle factors. Based on the abnormal sampling points, adjacent normal sampling points, and corresponding contour lines, the variation range of the abnormal indicators along the slope descent direction and the contour line extension direction is determined, and an initial abnormal influence zone is generated starting from the abnormal sampling points. Boundary verification points are set between the boundary of the initial abnormal influence zone and the adjacent normal sampling points, and the corresponding abnormal indicators are re-tested. If the verification result exceeds the judgment limit, the abnormal influence zone is expanded along this direction; if the verification result does not exceed the judgment limit, the location of the verification point is used as the abnormal boundary control point. Verification points are continued to be set along the corresponding direction at a preset verification interval until a verification result that does not exceed the judgment limit is obtained for the first time, and this point is used as the abnormal boundary control point. In this embodiment, the verification interval is set to 20m. Connecting each abnormal boundary control point, the spatial range of the abnormal soil is obtained, and this range is associated with the corresponding testing unit for subsequent individual identification, zonal storage, and re-testing of abnormal soil.

[0061] In one specific implementation, we take the proposed occupation of cultivated land for a road and supporting infrastructure construction project in a hilly area of ​​a basin in Sichuan Province as an example. As shown in Table 1, the target detection area is 111.9 hm². 2 Based on the construction occupation boundaries, the secondary land classification of cultivated land, and the contiguous relationship of land parcels, the area was divided into three soil testing units: paddy field soil testing unit, irrigated land soil testing unit, and dry land soil testing unit. Further, according to the spatial continuity of the land parcels, ten contiguous sampling areas were formed, including four paddy field contiguous sampling areas, two irrigated land contiguous sampling areas, and four dry land contiguous sampling areas. Soil samples were mainly collected from the 0–20 cm soil layer. The soil layer thickness was independently measured at the sampling points using soil profiles or drilling methods, and the sampling coordinates were recorded simultaneously.

[0062] Table 1. Project and Survey Overview ; The number of basic sampling points was determined based on the area of ​​each testing unit, and corrected for the hillside location, runoff path, and potential risk locations. Unit C1 covers the area from the top to the middle of the slope, so one additional slope location sampling point was added; Unit C3 is adjacent to an abandoned agricultural machinery repair shop, so one additional risk area sampling point was added; Unit C4 is located downstream of the hillside runoff, so one additional runoff deposition area sampling point was added. A total of 30 sampling points were ultimately set up, from P01 to P30. The specific soil testing units and sampling point configurations are shown in Table 2.

[0063] Table 2 Soil testing unit and sampling point configuration ; Basic tests were performed on all soil samples, including soil layer thickness, soil texture, pH, and organic matter. Additional tests were conducted on total nitrogen, available phosphorus, available potassium, bulk density, total water-soluble salts, gravel content, and cation exchange capacity, based on potential obstacle factors. Table 3 highlights the nutrient and obstacle factor test results. Original records for basic and pollution tests are separately linked to the sample numbers. The results indicate that no significant obstacles were observed in units A1, A3, and B1; basic test results for unit A2 reflected localized acidification; units A4 (P11 and P12) showed high bulk density; units B2 (P16 and P17) showed high salinity; unit C1 primarily showed low organic matter; unit C2 (P23) simultaneously showed high bulk density, high gravel content, and low organic matter; some sampling points in unit C3 showed compaction or low organic matter. Unit C3 underwent petroleum hydrocarbon testing based on risk information from abandoned agricultural machinery repair points, and unit C4 underwent heavy metal testing based on runoff deposition and upstream stockpiling information. These results were used to identify and delineate localized abnormal areas.

[0064] Table 3. Results of nutrient and barrier factor detection at sampling points ; During the testing process, blank samples, parallel samples, spiked recovery samples, and standard substances were used for quality control. The results are shown in Table 4. The blank samples were all below the method detection limit, the relative deviation of the parallel samples met the testing requirements, the spiked recovery rate was 88.4%–106.7%, and the measured values ​​of the standard substances were within the certificate's allowable range. All quality control results were qualified.

[0065] Table 4 Inspection Quality Control Record ; Finally, the results of basic testing, obstacle factor testing, and pollution testing are collected according to the soil testing units to form the regional soil testing results, which are used to determine the classification and storage of the soil to be stripped, conditioning measures, isolation range of local anomalies, and subsequent reuse destination.

[0066] like Figure 4 As shown, this invention provides a soil testing system for construction-occupied arable land areas. The system includes: a division module for acquiring boundary data and secondary land use category data of the construction-occupied arable land areas to divide the target testing area into multiple soil testing units; a sampling module for determining the number and location of sampling points based on the area of ​​each soil testing unit, and collecting soil samples according to the sampling points; a testing module for performing basic testing on the soil samples, and supplementary testing based on pollution risk information and barrier factor information of the corresponding soil testing units to obtain sample testing results; and an output module for summarizing the sample testing results according to the soil testing units to generate zonal soil testing results for the target testing area.

[0067] The present invention also provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the above-described method for detecting soil in areas of cultivated land occupied by construction.

[0068] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details described above. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe the various possible combinations.

[0069] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the embodiments of the present invention, they should also be regarded as the content disclosed by the embodiments of the present invention.

Claims

1. A method for soil testing in areas where construction has occupied arable land, characterized in that, The method includes: S1: Obtain the boundary data of the construction-occupied cultivated land area and the secondary land category map data of cultivated land to divide the target detection area into multiple soil detection units; S2: Determine the number and location of sampling points based on the area of ​​each soil testing unit, and collect soil samples according to the sampling points; S3: Perform basic testing on the soil sample, and perform supplementary testing based on the pollution risk information and barrier factor information of the corresponding soil testing unit to obtain the sample testing results; S4: Summarize the sample test results according to the soil testing unit to generate the zoned soil test results for the target testing area.

2. The method for soil testing in areas of cultivated land occupied by construction according to claim 1, characterized in that, The acquisition of boundary data for the construction-occupied cultivated land area and secondary land use category data of cultivated land is used to divide the target detection area into multiple soil detection units, including: Obtain boundary data for the area of ​​cultivated land occupied by construction, wherein the boundary data includes the coordinates of the construction occupation boundary and the closed boundary formed by the construction occupation boundary coordinates; Acquire the data of cultivated land secondary land category patches that spatially overlap with the closed boundary, wherein the cultivated land secondary land category patch data includes cultivated land patch boundary, cultivated land category type and patch area; The closed boundary and the cultivated land patch boundary are spatially superimposed, and the cultivated land patches falling within the closed boundary are cropped to obtain cultivated land detection patches located within the target detection area. The cultivated land detection patches are classified according to their cultivated land type. Cultivated land detection patches with the same cultivated land type are assigned to the same soil detection unit, while cultivated land detection patches with different cultivated land types are assigned to different soil detection units. The cropped areas of each cultivated land detection patch belonging to the same soil detection unit are summed to determine the area of ​​the corresponding soil detection unit.

3. The method for soil testing in areas of cultivated land occupied by construction according to claim 1, characterized in that, The process of determining the number and location of sampling points based on the area of ​​each soil testing unit includes: The total number of sampling points for each soil testing unit is determined based on the area of ​​each soil testing unit and the preset area threshold. The spatial continuity relationship between each cultivated land detection patch within the soil detection unit is identified, and one or more spatially continuous cultivated land detection patches are identified as the same contiguous sampling area, thus obtaining one or more contiguous sampling areas corresponding to the soil detection unit; Based on the proportion of the area of ​​each contiguous sampling area to the area of ​​the soil testing unit and the spatial separation relationship between each contiguous sampling area, the total number of sampling points is allocated to each contiguous sampling area to obtain the number of sampling points corresponding to each contiguous sampling area. Based on the boundaries of each contiguous sampling area and the corresponding number of sampling points, sampling points are generated within each contiguous sampling area, and the sampling points are located within the boundary range of the corresponding soil testing unit.

4. The method for soil testing in areas of cultivated land occupied by construction according to claim 1, characterized in that, The basic testing of the soil samples includes: When collecting the soil samples, the soil layer thickness at the corresponding sampling point of the soil sample is recorded to obtain the soil layer thickness detection results; The soil samples were subjected to soil texture testing to obtain the texture testing results; The pH of the soil sample was measured, and the pH results were obtained. The soil sample was subjected to organic matter testing, and the organic matter test results were obtained. The soil layer thickness test results, texture test results, pH test results, and organic matter test results are correlated with the soil test unit to which the corresponding soil sample belongs to obtain the basic test results.

5. The method for soil testing in areas of cultivated land occupied by construction according to claim 1, characterized in that, The supplementary detection based on the pollution risk information and barrier factor information of the corresponding soil detection unit includes: Acquire the previous soil pollution survey status, pollution history information, potential pollution source information, and potential soil barrier factor types corresponding to the soil testing unit; Based on the status of the previous soil pollution survey, determine whether to conduct pollution control index testing on the corresponding soil samples; Based on the pollution history information and the potential pollution source information, determine whether to perform characteristic pollutant detection on the corresponding soil samples; Based on the type of potential soil obstacle factor, specific obstacle factor testing items for the corresponding soil sample are determined from the preset obstacle factor testing items, and the soil sample is subjected to specific obstacle factor testing; wherein, the preset obstacle factor testing items include at least one of gravel content, total water-soluble salt, soil bulk density, cation exchange capacity, and available elements; The actual pollution control indicator detection results, characteristic pollutant detection results, and barrier factor-specific detection results are combined to form supplementary detection results; when none of the supplementary detections are triggered, an empty result set is used as the supplementary detection results.

6. The method for soil testing in areas of cultivated land occupied by construction according to claim 5, characterized in that, The process for detecting the pollution control indicators includes: When the soil testing unit corresponding to the previous soil pollution survey status characterization lacks previous soil pollution survey data, the applicable pollution risk control standard shall be determined according to the land use attribute of the soil testing unit. According to the pollution risk control standards, the pollution control indicators for the corresponding soil samples are determined from the preset pollution control indicator database; The content of the pollution control indicators in the soil samples was detected to obtain the measured content of each pollution control indicator. Obtain the pH test results of the soil samples, and determine the risk screening value or risk control value corresponding to each pollution control indicator based on the applicable pollution risk management standards and the pH test results; The measured content is compared with the corresponding risk screening value or risk control value to obtain the detection result of the pollution control indicator.

7. The method for soil testing in areas of cultivated land occupied by construction according to claim 5, characterized in that, The process for detecting the characteristic pollutants includes: When the soil testing unit corresponding to the pollution history information characterization has a pollution history, or when the soil testing unit corresponding to the potential pollution source information characterization is located within the influence range of the potential pollution source, the corresponding pollution source type is determined. Based on the pollution source type, the corresponding characteristic pollutant detection items are matched from the preset characteristic pollutant item library; The soil sample was subjected to content detection of the characteristic pollutants to obtain the measured content of the characteristic pollutants; The measured content of the characteristic pollutant is compared with the corresponding pollution risk judgment limit to obtain the detection result of the characteristic pollutant.

8. The method for soil testing in areas of cultivated land occupied by construction according to claim 1, characterized in that, The soil testing results are summarized according to the soil testing unit to generate the zonal soil testing results for the target testing area, including: Using soil testing units as the primary index and contiguous sampling areas as the secondary index, soil samples belonging to the same contiguous sampling area and their test results are collected, and then the test records of each contiguous sampling area are summarized to their respective soil testing units. Based on the sampling points of each soil sample, the sample test results are associated with the sampling locations within the corresponding soil testing unit; Based on the type of testing item, the basic testing results and supplementary testing results within the same soil testing unit are organized to obtain the unit testing record; The unit detection records are associated with the boundaries and arable land types of the corresponding soil detection units to generate the zonal soil detection results of the target detection area; The zonal soil testing results include soil testing unit boundaries, cultivated land type, contiguous sampling area boundaries, contiguous sampling area numbers, sampling points, soil samples, testing items, test values, and out-of-limit item markings.

9. A soil testing system for areas where arable land is occupied during construction, characterized in that, The system is used to perform the soil testing method for construction-occupied cultivated land areas as described in any one of claims 1-8, the system comprising: The segmentation module is used to obtain the boundary data of the construction-occupied cultivated land area and the secondary land category map data of cultivated land, so as to divide the target detection area into multiple soil detection units; The sampling module is used to determine the number and location of sampling points based on the area of ​​each soil testing unit, and to collect soil samples according to the sampling points. The detection module is used to perform basic detection on the soil sample and supplementary detection based on the pollution risk information and barrier factor information of the corresponding soil detection unit to obtain the sample detection results. The output module is used to summarize the sample test results according to the soil test unit and generate the zoned soil test results of the target test area.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed on a computer, cause the computer to perform the soil testing method for construction-occupied cultivated land areas as described in any one of claims 1-8.

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