Method for partitioning cultivated land soil in high background area

Abstract

The invention relates to the technical field of soil zoning, and discloses a high background area cultivated land soil zoning method, which comprises the following steps: uniformly dividing a target area into a plurality of sampling areas; agricultural product samples in the sampling area are collected, and the heavy metal content value of each agricultural product sample is obtained; counting whether the heavy metal content value of each agricultural product sample is greater than a first threshold value, if the heavy metal content values of more than 93% of the agricultural product samples are greater than the first threshold value, marking the agricultural product samples as a negative list, otherwise, marking the agricultural product samples as a positive list; the positive list and the negative list are respectively replaced by a number '0' and a number '1'; establishing a color mapping function according to the data of each sampling area; performing kernel density estimation on the data of each sampling area; drawing a thermodynamic diagram for the color mapping function and the data subjected to kernel density estimation through ArcGIS; and performing cultivated land partitioning on the target area according to a result of the thermodynamic diagram. The problem that cultivated land is inconvenient to divide in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the technical field of soil zoning, and more particularly to a method for zoning cultivated land soil in a high background area. Background Art

[0002] Soil high background areas refer to areas where the content of certain elements or compounds in the soil is higher than the normal background value, which may pose a potential threat to crop growth and human health. With the influence of human activities, some areas that are usually considered to have a low risk of exceeding the standard for crops have also seen agricultural products.

[0003] Southwest my country is home to a large area of ​​carbonates, black shales and basalts, making it one of the richest mineral resource regions in my country. However, this has also led to the fact that the content of heavy metal elements in regional farmland soil is significantly higher than the national average, and the soil heavy metal point exceeding standard rate ranks first in the country. It is a typical geological high background area in my country. The amount of heavy metal enrichment in crops has the most direct relationship with the content and form of heavy metals in the soil.

[0004] According to the Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (GB15618-2018), the current screening and classification of cultivated land soil pollution risks is mainly through comparing the heavy metal content in cultivated land soil with the agricultural land soil pollution risk screening value and control value. This is because different crop types have great differences in the absorption and accumulation of heavy metals, and the occurrence forms and environmental risks of heavy metals in soils in geological high background areas are significantly different from those in human-polluted areas.

[0005] The existing soil high background area zoning is mainly to determine whether the area is a controlled area or a cultivable area directly after the inspection personnel inspect the cultivated land. This method cannot directly observe the distribution of high background areas in the target area, and it is not convenient to classify the cultivated land. Summary of the invention

[0006] The present application provides a method for zoning cultivated land soil in high background areas, aiming to solve the problem that the prior art is inconvenient for categorizing cultivated land.

[0007] In one embodiment, a method for zoning cultivated land soil in a high background area is provided, comprising the following steps: The target area is evenly divided into multiple sampling areas; Collaboratively collecting soil and agricultural product samples in the sampling area, where the number of the same agricultural product sample is multiple, and obtaining the heavy metal content value of each of the soil and agricultural product samples; Counting whether the heavy metal content value of each of the agricultural product samples is greater than a first threshold value, if more than 93% of the agricultural product samples have a heavy metal content value greater than the first threshold value, marking the agricultural product samples as a negative list, otherwise marking the agricultural product samples as a positive list; Marking the negative list and the positive list on the corresponding sampling areas; The positive list and the negative list are replaced by the number “0” and the number “1” respectively; Counting the data of each sampling area and superimposing the data, and establishing a color mapping function according to the data of each sampling area; Performing kernel density estimation on the data of each sampling area; The color mapping function and the data after kernel density estimation were used to draw a heat map through ArcGIS; The target area is partitioned into cultivated land areas according to the results of the heat map.

[0008] In one embodiment, the types of heavy metals include: cadmium, arsenic, chromium, lead, and mercury.

[0009] Specifically, when the heavy metal content of any type of the agricultural products exceeds the first threshold, the heavy metal content value of the agricultural product sample is considered to be greater than the first threshold.

[0010] In one embodiment, the types of agricultural products in the agricultural product sample include: wheat, rice, corn, pepper, ginseng fruit, etc.

[0011] In one embodiment, the number of each type of agricultural product samples is at least 10.

[0012] In one embodiment, the agricultural product samples are collected over a period of at least two years.

[0013] In one embodiment, the color mapping function is: ; Wherein, C represents the color value, and its value range is: [0, 255]; R represents the data value, and its value range is: [0, n]; and the value of n is the maximum value of the sampling area data within the target area.

[0014] Specifically, assuming the data range is [0, 100] and the color range is [0, 255], calculate the color value corresponding to the data value 50: Substitute the values:

[0015] Calculation: C = 127.5 Therefore, a data value of 50 corresponds to a color value of 127.5.

[0016] In one embodiment, the kernel density estimation is performed using the following function: ; Then scale the K(x) function by bandwidth h to get the following function: , where x is the corresponding data in each sampling area after statistics; h is the bandwidth, and h>0.

[0017] In one solution, the sampling areas corresponding to the positive list are all safe planting areas. The sampling areas corresponding to the negative list are judged whether the predetermined metal content of the soil in the area is greater than a second threshold. If so, the corresponding sampling areas are used as control areas; if not, the corresponding sampling areas are used as safe planting areas.

[0018] Specifically, soil content less than the second threshold is safe arable land and is marked with the number 0; soil content greater than the second threshold is key controlled arable land and is marked with the number 1.

[0019] In one embodiment, the predetermined metal types include: cadmium, arsenic, chromium, lead, and mercury.

[0020] In one embodiment, the ArcGIS is a geographic information system.

[0021] Beneficial effects of this application: This application improves the accuracy of arable land classification by conducting coordinated soil and crop sample collection and monitoring and threshold comparison in the target area.

[0022] By replacing the positive list and the negative list with the number "0" and the number "1" respectively, a computer-recognizable text is formed, which facilitates subsequent data processing by the computer, reduces the workload of staff, and improves the efficiency of arable land zoning.

[0023] After drawing a heat map through ArcGIS using the color mapping function and the data after kernel density estimation, the staff can intuitively and clearly know the distribution of the positive list and the negative list through the heat map, and can quickly understand the distribution of heavy metals in the soil in the high background area, and can quickly classify the cultivated land, that is, quickly divide the cultivated land that can be safely planted and the cultivated land that can be controlled. At the same time, the heat map can help the staff quickly determine the area between the cultivated land that can be safely planted and the cultivated land that can be controlled, and conduct further testing on it. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 This is a flow chart of a method for zoning cultivated land soil in a high background area in an embodiment of the present application; Figure 2 This is a heat map of safe planting of crops on the negative list of cultivated land in the high background area of ​​Shilin County in one embodiment of the present application. DETAILED DESCRIPTION

[0026] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application rather than all embodiments, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0031] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0032] The present application makes improvements and innovations and proposes the following embodiments.

[0033] In some embodiments, see Figure 1 , provides a method for zoning cultivated land soil in a high background area, comprising the following steps: S1. Evenly divide the target area into multiple sampling areas; S2. Collect soil and agricultural product samples in the sampling area, and the number of the same agricultural product samples is multiple, and obtain the heavy metal content value of each agricultural product sample; S3. Count whether the heavy metal content value of each agricultural product sample is greater than the first threshold value. If the heavy metal content value of more than 93% of the agricultural product samples is greater than the first threshold value, the agricultural product samples are marked as a negative list, otherwise the agricultural product samples are marked as a positive list; S4. Mark the negative list and the positive list on the corresponding sampling areas; the positive list and the negative list are replaced by the number "0" and the number "1" respectively; S5, counting the data of each sampling area and superimposing the data, and establishing a color mapping function according to the data of each sampling area; S6. Perform kernel density estimation on the data of each sampling area; S7, using ArcGIS to draw a heat map of the data after the color mapping function and kernel density estimation; S8. Divide the target area into cultivated land zones according to the results of the heat map.

[0034] Sampling is carried out by evenly dividing the target area into sampling areas, thereby improving the accuracy of cultivated land division.

[0035] By replacing the positive list and the negative list with the number "0" and the number "1" respectively, a computer-recognizable text is formed, which facilitates subsequent data processing by the computer, reduces the workload of staff, and improves the efficiency of arable land zoning.

[0036] After drawing a heat map through ArcGIS using the color mapping function and the data after kernel density estimation, the staff can intuitively and clearly know the distribution of the positive list and the negative list through the heat map, which is convenient for the staff to divide the cultivated land areas, facilitate management and decision-making.

[0037] In some embodiments, the types of heavy metals include: cadmium, arsenic, chromium, lead, and mercury. These heavy metals are the main heavy metals that have a greater impact on humans and are also common heavy metals in high-background farmland.

[0038] In some embodiments, the types of agricultural products in the agricultural product sample include: wheat, rice, corn, pepper, and ginseng fruit.

[0039] Specifically, when the content of any type of heavy metal in any agricultural product exceeds the first threshold, the heavy metal content value of the agricultural product sample is considered to be greater than the first threshold; the first thresholds for cadmium, arsenic, chromium, lead, and mercury content are shown in Table 1 below:

[0040] The first threshold is set according to "GB 2762-2005 Limits of Contaminants in Food" and "National Food Safety Standard Limits of Contaminants in Food" (GB 2762-2017), and is in line with national standards.

[0041] In some embodiments, the number of agricultural product samples of each type is at least 10. The number of samples under this value can better meet the kernel density estimation, so that the data after scaling is not distorted, and the color transition of the drawn heat map is smooth.

[0042] In some embodiments, the agricultural product samples are collected for at least two years. Only by collecting data for two years can more realistic data information be obtained, which facilitates more accurate division of cultivated land. Through two years of continuous monitoring, the cultivated land area is dynamically adjusted, and the plantable area is dynamically updated and accurately judged.

[0043] In some embodiments, the color mapping function is: ; Where C represents the color value, and its value range is: [0, 255]; R represents the data value, and its value range is: [0, n]; n is the maximum value of the sampling area data in the target area. n is a natural number.

[0044] The color mapping function can more intuitively show the data of each sampling area. When the color mapping function is used with ArcGIS to draw a heat map, the distribution of the positive list and negative list in the high background area can be intuitively seen, which is convenient for the subsequent division of cultivated land.

[0045] Specifically, assuming the data range is [0, 100] and the color range is [0, 255], calculate the color value corresponding to the data value 50: Substitute the values:

[0046] Calculation: C = 127.5 Therefore, a data value of 50 corresponds to a color value of 127.5.

[0047] In some embodiments, kernel density estimation is performed using the following function: ; Then scale the K(x) function by bandwidth h to get the following function: , where x is the corresponding data in each sampling area after statistics; h is the bandwidth, and h>0.

[0048] By scaling the K(x) function according to the bandwidth h and then drawing the data through ArcGIS, the color transition of the heat map can be smoother. At the same time, too large an h value will also distort the data.

[0049] Specifically, the value range of h is 6>h>0. The value of h is determined by the staff according to the actual situation.

[0050] In some embodiments, the sampling areas corresponding to the negative list are collected and it is determined whether the predetermined metal content of the soil, parent rock, and parent material in each sampling area is greater than the second threshold. If so, the corresponding sampling area is used as a control area; if not, the corresponding sampling area is used as a planting area. By testing the corresponding heavy metal content value of the soil in the sampling area, it is convenient to divide the cultivated land more reasonably in the future.

[0051] Among them, the sampling areas corresponding to the positive list are all safe planting areas. Even if the heavy metal content in the soil in the sampling areas corresponding to the positive list exceeds the standard, it is still a positive list.

[0052] Specifically, soil content less than the second threshold is safe for planting and is marked with the number 0; soil content greater than the second threshold is key controlled land and is marked with the number 1. For the negative list, soil metal content is tested and the sampling area is divided more accurately, so that the heat map generated later can more accurately express the planting area and the controlled area.

[0053] Specifically, in the negative list, even if the metal content of the soil, parent rock, or parent material is greater than the second threshold, it can be considered a plantable area.

[0054] In some embodiments, the predetermined metal types include: cadmium, arsenic, chromium, lead, and mercury.

[0055] Specifically, the soil-crop collaborative monitoring data is used to calculate the crop enrichment coefficient, and the ranking method is used to derive the soil threshold based on crop safety production. The reference value of the second threshold is shown in the following table:

[0056] Among them, the others in Table 2 refer to dry land other than paddy fields.

[0057] The second threshold value set in Table 2 is reasonably set and can cover more paddy fields and other cultivated land. At the same time, the pH value parameter is introduced to facilitate more reasonable detection and zoning.

[0058] In some embodiments, ArcGIS is a geographic information system.

[0059] Specifically, the color correspondence function and kernel density estimation are entered into ArcGIS in a program. Through this system, the staff only needs to input the corresponding data (digital 0 or 1) of the corresponding sampling area into the system, and then select the appropriate bandwidth h value to generate a suitable heat map. The map output efficiency is high, which reduces the labor intensity of the staff.

[0060] The staff used the generated heat map to divide the cultivated areas and control areas on the heat map.

[0061] In one embodiment, Shilin County is located in a typical high-background soil area. 614 major agricultural products were collected in Shilin County for two consecutive years, including wheat, rice, corn, pepper, ginseng fruit, etc. The cadmium, arsenic, chromium, lead, and mercury elements in the agricultural products were tested. After comparing with the first threshold of the corresponding agricultural products, 414 agricultural products did not exceed the heavy metal content, and 73 agricultural products exceeded the heavy metal content. At the same time, the areas where the heavy metal products were located were also tested for cadmium, arsenic, chromium, lead, nickel, zinc, copper, and mercury in the soil. And the method of this application was used to draw the following Figure 2 Heat map shown.

[0062] in, Figure 2 The green part is the arable area, the yellow part is the controlled area, and the redder the color, the more serious the excessive heavy metal content.

[0063] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for zoning cultivated land soil in high background areas, characterized in that: The steps include: The target area is evenly divided into multiple sampling areas; Collecting soil and agricultural product samples in the sampling area, where the number of the agricultural product samples is multiple, and obtaining the heavy metal content value of each of the agricultural product samples; Counting whether the heavy metal content value of each of the agricultural product samples is greater than a first threshold value, if more than 93% of the agricultural product samples have a heavy metal content value greater than the first threshold value, marking the agricultural product samples as a negative list, otherwise marking the agricultural product samples as a positive list; Marking the negative list and the positive list on the corresponding sampling areas; The positive list and the negative list are replaced by the number "0" and the number "1" respectively; Counting the data of each sampling area and superimposing the data, and establishing a color mapping function according to the data of each sampling area; Performing kernel density estimation on the data of each sampling area; Using ArcGIS to draw a heat map of the color mapping function and the data after kernel density estimation; The target area is partitioned into cultivated land areas according to the results of the heat map.

2. The method for zoning cultivated land soil in high background area according to claim 1, characterized in that: The types of heavy metals include: cadmium, arsenic, chromium, lead and mercury.

3. The method for zoning cultivated land soil in high background area according to claim 1, characterized in that: The types of agricultural products in the agricultural product samples include: wheat, rice, corn, pepper, and ginseng fruit.

4. The method for zoning cultivated land soil in high background area according to claim 3, characterized in that: The number of each type of agricultural product samples is at least 10.

5. The method for zoning cultivated land soil in high background area according to claim 4, characterized in that: The agricultural product samples are collected over a period of at least two years.

6. The method for zoning cultivated land soil in high background area according to any one of claims 1 to 5, characterized in that: The color mapping function is: ; Wherein, C represents the color value, and its value range is: [0, 255]; R represents the data value, and its value range is: [0, n]; and the value of n is the maximum value of the sampling area data within the target area.

7. The method for zoning cultivated land soil in high background area according to claim 6, characterized in that: The kernel density estimation is performed using the following function: ; Then scale the K(x) function by bandwidth h to get the following function: , where x is the corresponding data in each sampling area after statistics; h is the bandwidth, and h>

0.

8. The method for zoning cultivated land soil in high background area according to claim 1, characterized in that: The sampling areas corresponding to the positive list are all safe planting areas. Soil sampling is carried out on the sampling areas corresponding to the negative list, and it is detected whether the content of the predetermined metal in the soil sample is greater than the second threshold. If so, the corresponding sampling area is used as a controlled area; if not, the corresponding sampling area is used as a planting area.

9. The method for zoning cultivated land soil in high background area according to claim 8, characterized in that: The predetermined metal types include: cadmium, arsenic, chromium, lead, and mercury.

10. The method for zoning cultivated land soil in high background area according to claim 1, characterized in that: The ArcGIS is a geographic information system.

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