A non-destructive detection method and system for heavy metal pollution of oil tea trees

Abstract

The present invention relates to the technical field of soil remediation, and specifically relates to a non-destructive detection method and system for heavy metal pollution in oil tea plantations, including: obtaining the daily sample spectrograms of the oil tea plantations and selecting several soil improvement days therefrom; obtaining the content of each heavy metal in the daily samples according to the daily sample spectrograms; obtaining the characteristic distances of each soil improvement day according to the content of each heavy metal in the daily samples; obtaining the primary pH value reduction of the soil improvement days according to the characteristic distances of adjacent soil improvement days; and correcting the primary pH value reduction of the soil improvement days according to the characteristic distances of each day between adjacent soil improvement days to obtain the pH value reduction of the soil improvement days. By detecting the content of various heavy metals in the soil of the oil tea plantations and combining with the absorption rate of heavy metals by the oil tea trees, the present invention gradually solidifies the heavy metals in the soil and avoids affecting the normal growth of the oil tea trees when improving the soil quality.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and particularly relates to a method and system for non-destructive detection of heavy metal pollution in oil tea trees. Background Art

[0002] Heavy metals in the soil of oil tea gardens can hinder the root development of oil tea trees in the oil tea gardens, inhibit the photosynthesis of oil tea trees, and at the same time, heavy metals in the soil of oil tea gardens can also inhibit the activity of beneficial microorganisms in the soil, thereby endangering the growth and development of oil tea trees. Therefore, it is necessary to detect the heavy metal content in the soil of oil tea gardens and improve the soil quality of oil tea gardens. However, when improving the soil quality by spreading acidifying agents in the traditional way, the impact on the oil tea trees in the oil tea gardens is not considered. Since when the pH value of the soil suddenly changes significantly, it will damage the roots of the oil tea trees and affect the absorption of nutrients by the oil tea trees. At the same time, it will also change the microbial community in the soil, resulting in a decrease in the activity of beneficial microorganisms in the soil, and further endangering the growth and health of oil tea trees; that is, the traditional method of improving soil quality will endanger the growth and health of oil tea trees. Summary of the Invention

[0003] The present invention provides a method and system for non-destructive detection of heavy metal pollution in oil tea trees to solve the existing problem: the traditional method of improving soil quality will endanger the growth and health of oil tea trees.

[0004] The method and system for non-destructive detection of heavy metal pollution in oil tea trees of the present invention adopt the following technical solutions:

[0005] An embodiment of the present invention provides a method for non-destructive detection of heavy metal pollution in oil tea trees, and the method includes the following steps:

[0006] Obtain the daily sample spectrograms of the oil tea garden and select several soil improvement days therefrom;

[0007] According to the daily sample spectrograms, obtain the content of each heavy metal in the daily samples;

[0008] According to the content of each heavy metal in the daily samples and the content of each heavy metal in all the previous samples, construct the daily sample space, obtain several cluster classes in the daily sample space; according to the several cluster classes in the sample space of each soil improvement day, obtain the characteristic distance of each soil improvement day; according to the characteristic distances of adjacent soil improvement days, obtain the primary pH value reduction of the soil improvement day;

[0009] According to the characteristic distances of each day between adjacent soil improvement days, obtain the change fitting line of the soil improvement day; according to the change fitting line of the soil improvement day, correct the primary pH value reduction of the soil improvement day to obtain the pH value reduction of the soil improvement day.

[0010] Preferably, the method for obtaining the daily sample spectrogram of the oil tea garden and selecting several soil improvement days therefrom includes the following specific steps:

[0011] For the th day, randomly select sampling points in the oil tea garden. At each sampling point in the oil tea garden, collect grams of soil. Place the collected soil in a fume hood to air-dry, grind the air-dried soil with a mortar to obtain soil powder, and filter the soil powder with a purpose sieve to obtain the test sample for the th day. Use a spectrometer to detect the test sample for the th day to obtain the sample spectrogram for the th day; the , and are respectively the preset number of sampling points, the quality of soil collection, and the sieve specification;

[0012] Preset a soil improvement cycle , and record the date of the 1st day and every days after the 1st day as soil improvement days.

[0013] Preferably, the method for obtaining the content of each heavy metal in the daily sample according to the daily sample spectrogram includes the following specific steps:

[0014] For the content of the th heavy metal in the sample for the th day; obtain the characteristic wavelength band of the th heavy metal and set the content limit of the th heavy metal; obtain the spectrogram when the content of the th heavy metal in the oil tea garden soil is the content limit and record it as the reference spectrogram. Denote the curve segment in the reference spectrogram corresponding to the characteristic wavelength band of the th heavy metal as the reference curve segment; according to the curve segment in the sample spectrogram for the th day corresponding to the characteristic wavelength band of the th heavy metal, combined with the reference curve segment and the content limit, obtain the content of the th heavy metal in the sample for the th day.

[0015] Preferably, the method for obtaining the content of the th heavy metal in the sample for the th day includes the following specific calculation formula:

[0016]

[0017] In the formula, represents the The content of the th heavy metal in the sample of the day; represents the limit value of the content of the th heavy metal; represents the definite integral of the curve segment of the characteristic band of the th heavy metal in the sample spectrogram of the day; represents the definite integral of the reference curve segment;

[0018] Preferably, the specific method for constructing the sample space of each day and obtaining several clusters in the sample space of each day according to the content of each heavy metal in the sample of each day and the content of each heavy metal in all previous samples is as follows:

[0019] Construct an N-dimensional sample space, where N is the number of heavy metal types; for the th day, the samples of the th day and the samples before the th day are recorded as target samples. According to the content of each heavy metal in each target sample, all target samples are placed into the sample space, and each target sample is used as a data point in the sample space to obtain the sample space of the th day;

[0020] Use the DBSCAN clustering algorithm to cluster the data points in the sample space of the th day. The distance metric uses the Euclidean distance between data points to obtain several clusters in the sample space of the th day.

[0021] Preferably, the specific method for obtaining the characteristic distance of each soil improvement day according to several clusters in the sample space of each soil improvement day includes:

[0022] For the th soil improvement day, the cluster in the sample space of the th soil improvement day that contains the data point corresponding to the th soil improvement day is recorded as the target cluster in the sample space of the th soil improvement day, and the distance between the center of the target cluster in the sample space of the th soil improvement day and the origin of the sample space is recorded as the characteristic distance of the th soil improvement day.

[0023] Preferably, the specific calculation formula for obtaining the primary pH value reduction of the soil improvement day according to the characteristic distances of adjacent soil improvement days is:

[0024]

[0025] In the formula, represents the primary pH reduction value on the th soil improvement day; represents the pH reduction value on the th soil improvement day; represents the characteristic distance on the th soil improvement day; represents the characteristic distance on the th soil improvement day; represents the characteristic distance on the th soil improvement day; represents the characteristic distance on the th soil improvement day; represents traversing the differences in characteristic distances between all adjacent soil improvement days before the th soil improvement day and taking the maximum value function.

[0026] Preferably, the method for obtaining the change fitting line of the soil improvement day according to the characteristic distance between adjacent soil improvement days specifically includes:

[0027] For any soil improvement day, record the date between the previous soil improvement day and the current soil improvement day as the change day, and obtain the characteristic distance of each change day;

[0028] Taking the date as the horizontal axis and the characteristic distance of the change day as the vertical axis, construct a rectangular coordinate system, and place each change day as a coordinate point into the rectangular coordinate system to obtain the change scatter plot of the soil improvement day; use the least squares method to perform linear fitting on the change scatter plot of the soil improvement day to obtain the change fitting line of the soil improvement day.

[0029] Preferably, the method for correcting the primary pH reduction value of the soil improvement day according to the change fitting line of the soil improvement day to obtain the pH reduction value of the soil improvement day specifically includes:

[0030] For any soil improvement day, correct the primary pH reduction value of the soil improvement day according to the root mean square error of the change fitting line of the soil improvement day and the slope of the change fitting line of the soil improvement day to obtain the pH reduction value of the soil improvement day. The specific calculation formula is:

[0031]

[0032] In the formula, represents the pH reduction value of the soil improvement day; represents the primary pH reduction value of the soil improvement day; Denote the root mean square error of the change fitting line of the soil improvement date; Denote the slope of the change fitting line of the soil improvement date; Denote the sigmoid function.

[0033] Another embodiment of the present invention provides a non-destructive detection system for heavy metal pollution of oil tea trees, including a memory, a processor, and a computer program stored in the memory and operable on the processor. When the processor executes the computer program, the steps of any one of the above-mentioned non-destructive detection methods for heavy metal pollution of oil tea trees are implemented.

[0034] The beneficial effects of the technical solution of the present invention are as follows: In this application, by obtaining the daily sample spectrograms of the oil tea garden and selecting several soil improvement dates therefrom; according to the daily sample spectrograms, obtaining the content of each heavy metal in the daily samples; according to the content of each heavy metal in the daily samples, obtaining the characteristic distance of each soil improvement date. The characteristic distance of the soil improvement date represents the content of various heavy metals in the samples of the soil improvement date. The larger the characteristic distance, the greater the content of various heavy metals in the corresponding samples. When the difference in the characteristic distance between adjacent soil improvement dates is larger, it indicates that the oil tea tree absorbs more heavy metals from the soil, and there are more heavy metals not solidified in the soil. Therefore, it is more necessary to reduce the pH value of the soil to solidify the heavy metals in the soil and prevent the heavy metals from being absorbed by the oil tea tree.

[0035] According to the daily characteristic distances between adjacent soil improvement dates, obtain the change fitting line of the soil improvement date. The smaller the slope of the change fitting line of the soil improvement date, the more heavy metals the oil tea tree absorbs during this period, and the more it will harm the health of the oil tea tree. Then, the greater the decrease in its pH value should be made. And the larger the value of the root mean square error of the change fitting line of the soil improvement date, the greater the difference in the amount of heavy metals absorbed by the oil tea tree from the soil every day, that is, it indicates that the oil tea tree has been harmed by the heavy metals in the soil and cannot stably absorb energy from the soil. Then, the greater the decrease in its pH value should be made; according to the change fitting line of the soil improvement date, correct the primary pH value decrease value of the soil improvement date to obtain the pH value decrease value of the soil improvement date, so as to gradually solidify the heavy metals in the soil and avoid affecting the normal growth of the oil tea tree when improving the soil quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 The flowchart of the steps of a non-destructive detection method for heavy metal pollution of Camellia oleifera trees according to the present invention. Specific embodiments

[0038] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following combines the accompanying drawings and preferred embodiments to detail the specific embodiments, structures, features and effects of a non-destructive detection method and system for heavy metal pollution of Camellia oleifera trees according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0040] The following specifically describes the specific solutions of a non-destructive detection method and system for heavy metal pollution of Camellia oleifera trees provided by the present invention with reference to the accompanying drawings.

[0041] Please refer to Figure 1 , which shows the flowchart of the steps of a non-destructive detection method for heavy metal pollution of Camellia oleifera trees provided by an embodiment of the present invention. The method includes the following steps:

[0042] Step S001: Obtain the daily sample spectrograms of the Camellia oleifera orchard and select several soil improvement days from them.

[0043] It should be noted that the ultimate goal of this embodiment is to prevent Camellia oleifera trees from absorbing excessive heavy metals during growth, resulting in shortened root lengths, reduced root weights and leaf weights of Camellia oleifera trees, seriously endangering the health of Camellia oleifera trees. At the same time, heavy metals will also affect the photosynthesis of Camellia oleifera trees, thus hindering the growth and development of Camellia oleifera trees and reducing the environmental adaptability of Camellia oleifera trees; therefore, this embodiment proposes a non-destructive detection method for heavy metal pollution of Camellia oleifera trees, while detecting the heavy metal content in the soil of the Camellia oleifera orchard, gradually improving the degree of heavy metal pollution in the Camellia oleifera orchard.

[0044] It should be further noted that an acidic environment can promote the conversion of heavy metals into insoluble precipitates, thereby reducing the absorption of heavy metals by Camellia oleifera in the oil tea garden. The acidic environment can increase the activity of antioxidant enzymes in plants and reduce the oxidative stress caused by heavy metals. At the same time, acidifying the soil can improve the living environment of the microbial community in the soil, contribute to the transformation and fixation of heavy metals, and further reduce the harm of heavy metals. However, in the process of improving the soil quality of the oil tea garden, if the pH value of the soil is suddenly changed significantly, it will damage the root system of Camellia oleifera and affect its absorption of nutrients. At the same time, it will also change the microbial community in the soil, resulting in a decrease in the activity of beneficial microorganisms in the soil, and thus endangering the growth and health of Camellia oleifera. Therefore, the improvement of soil quality by reducing the pH value of the soil should be carried out slowly to ensure the healthy growth of Camellia oleifera.

[0045] Specifically, for the th day, randomly select sampling points in the oil tea garden. At each sampling point in the oil tea garden, collect grams of soil. Put the collected soil in a fume hood to air dry, grind the air-dried soil with a mortar to obtain soil powder, and filter the soil powder with a purpose sieve to obtain the test sample for the th day. Use a spectrometer to detect the test sample for the th day to obtain the sample spectrogram for the th day. Similarly, obtain the sample spectrogram for each day; the , and are respectively the preset number of sampling points, the quality of soil collection, and the sieve specification. The specific values of , and can be set according to the actual situation by yourself, and there is no hard requirement in this embodiment. In this embodiment, , , are used as examples for description. The specific process of collecting the spectrogram by the spectrometer is a well-known prior art, so it will not be elaborated in this embodiment.

[0046] Furthermore, preset an initial pH value reduction and a soil improvement period . The specific values of and can be set according to the actual situation by yourself, and there is no hard requirement in this embodiment. In this embodiment, , are used for description; starting from the 1st day, after obtaining the sample spectrogram for the 1st day, by spreading acidic substances on the soil of the oil tea garden, make the pH value of the soil in the oil tea garden decrease by , and every After obtaining the spectrogram, the pH value of the soil in the oil tea garden is reduced according to the previously collected spectrograms, thereby gradually improving the soil quality of the oil tea garden, and the date of reducing the pH value of the soil in the oil tea garden is recorded as the soil improvement date; the spreading of acidic substances on the soil in the oil tea garden includes: ferrous sulfate, aluminum sulfate, acetic acid, etc., and there are no rigid requirements in this embodiment, and it can be specifically set according to the actual situation; the subsequent content is the processing process of obtaining the pH reduction value for each soil improvement date.

[0047] It should be noted that by acidifying the soil contaminated by heavy metals, the binding rate of heavy metals in the soil with minerals or organic substances in the soil can be increased, making the heavy metals in the soil easier to be fixed, thereby reducing the absorption of heavy metals by the oil tea trees in the oil tea garden and reducing the toxicity of heavy metals in the soil to plants.

[0048] Thus, the sample spectrograms for each day are obtained.

[0049] Step S002: According to the sample spectrograms for each day, obtain the content of each heavy metal in the sample for each day.

[0050] It should be noted that as a non-destructive detection method for heavy metal pollution of oil tea trees, in this embodiment, specifically, by detecting the heavy metal content in the soil of the oil tea garden to improve the soil quality of the oil tea garden, it is first necessary to obtain the content of various heavy metals in the sample for each day. And the heavy metals in the sample will absorb light in specific bands, and there are differences in the bands of light absorbed by different heavy metals, so based on this, the content of heavy metals in the sample can be obtained.

[0051] Preferably, in a specific embodiment of the present invention, for the th day sample, the content of the th heavy metal; obtain the characteristic band of the th heavy metal and set the content limit value of the th heavy metal. The content limit value of the th heavy metal can be set according to actual requirements. In this embodiment, it is set according to the requirements in the "Soil Environmental Quality Standards for Agricultural Land (Third Draft for Soliciting Opinions)"; obtain the spectrogram when the content of the th heavy metal in the soil of the oil tea garden is the content limit value and record it as the reference spectrogram, and record the curve segment in the reference spectrogram located in the characteristic band of the th heavy metal as the reference curve segment; according to the curve segment in the sample spectrogram of the th day located in the characteristic band of the th heavy metal, combined with the reference curve segment and the content limit value, obtain the content of the th heavy metal in the th day sample. The specific calculation formula is:

[0052]

[0053] In the formula, represents the content of the th heavy metal in the sample on the th day; represents the content limit of the th heavy metal; represents the definite integral of the curve segment in the characteristic wavelength band of the th heavy metal in the sample spectrum on the th day; represents the definite integral of the reference curve segment; represents the hyperbolic tangent function, which is used to map the calculation result to the range of (-1, 1) in this embodiment.

[0054] It should be further noted that the characteristic wavelength band of the th heavy metal represents the specific wavelength band of the light absorbed by the th heavy metal; the reference curve segment represents the spectral curve at the characteristic wavelength band of the th heavy metal when the content of the th heavy metal in the sample reaches the content limit; and when the area (definite integral of the curve segment) enclosed by the curve segment in the characteristic wavelength band of the th heavy metal in the sample spectrum on the th day and the horizontal axis is greater than the area (definite integral of the curve segment) enclosed by the reference curve segment and the horizontal axis, it indicates that the content of the th heavy metal in the sample spectrum on the th day is greater than the content limit of the th heavy metal, and thus the content of various heavy metals in the sample is obtained in this way.

[0055] Thus, the content of each heavy metal in the sample of each day is obtained.

[0056] Step S003: According to the content of each heavy metal in the sample of each day and the content of each heavy metal in all its previous samples, construct the sample space of each day, and obtain several clusters in the sample space of each day; according to several clusters in the sample space of each soil improvement day, obtain the characteristic distance of each soil improvement day; according to the characteristic distances of adjacent soil improvement days, obtain the primary pH value reduction of the soil improvement day.

[0057] It should be noted that usually soil is always contaminated by multiple heavy metals, and there are differences in the effects of different heavy metals on plants growing in the soil. For example, the microbial biomass carbon and nitrogen in soil contaminated by heavy metals such as copper, zinc, chromium, and lead are significantly negatively correlated with the contents of copper, zinc, chromium, and lead, while chromium will seriously affect the bacterial community structure in the soil. Therefore, in this embodiment, the contents of each heavy metal in the daily samples are used to cluster the samples to reflect the contents of various heavy metals in different samples.

[0058] Preferably, in a specific embodiment of the present invention, an N-dimensional sample space is constructed, where N is the number of heavy metal types; for the th day, the samples before the th day and the th day are denoted as target samples. According to the content of each heavy metal in each target sample, all target samples are placed into the sample space, and each target sample is used as a data point in the sample space to obtain the sample space on the th day.

[0059] Furthermore, the DBSCAN clustering algorithm is used to cluster the data points in the sample space on the th day, and the Euclidean distance between data points is used as the distance metric to obtain several clusters in the sample space on the th day. Since the DBSCAN clustering algorithm is a well-known existing technology, it will not be elaborated in this embodiment.

[0060] Similarly, several clusters in the sample space of each day are obtained.

[0061] It should be noted that the samples in the cluster have similar metal contents; and the acidic environment will increase the degree of combination between heavy metal elements and organic matter in the soil. As a soluble organic mixture with rich functional groups and complex structures, the change in the content of organic matter will have a huge impact on the morphological changes of heavy metals in the soil. It can provide adsorption sites for heavy metals, which is conducive to the solidification of heavy metals in the soil, thereby reducing the absorption of heavy metals by plants and weakening the impact of heavy metals on Camellia oleifera trees in the oil tea orchard.

[0062] It should be further noted that when acidifying the soil to solidify heavy metals in the soil, the content of heavy metals in the soil is not reduced, but the absorption of heavy metals by Camellia oleifera trees is avoided. When the content of heavy metals in the soil decreases, it means that the heavy metals in the soil are absorbed by Camellia oleifera trees. Therefore, when the content of heavy metals in the soil decreases after acidifying the soil, it means that there are heavy metals in the soil that have not been solidified and are absorbed by Camellia oleifera trees, and the heavy metals in the soil need to be further solidified.

[0063] Preferably, in a specific embodiment of the present invention, for Soil Improvement Day The sample space of the soil improvement day contains The cluster of data points corresponding to the soil improvement day is recorded as The target clusters in the sample space of the soil improvement day are The distance between the target cluster center and the origin of the sample space in the sample space of the soil improvement day is recorded as characteristic distance of soil improvement days;

[0064] Furthermore, for the Soil improvement day, according to and The characteristic distance of the soil improvement day, combined with the The pH value decreased by the soil improvement day, and the The specific calculation formula for the reduction of primary pH value on soil improvement day is:

[0065]

[0066] In the formula, Indicates Primary pH reduction per soil improvement day; Indicates pH reduction value per soil improvement day; Indicates characteristic distance of soil improvement days; Indicates characteristic distance of soil improvement days; Indicates characteristic distance of soil improvement days; Indicates characteristic distance of soil improvement days; Expressing the The differences in characteristic distances of all adjacent soil improvement days before the soil improvement day are traversed, and the maximum value function is taken.

[0067] It should be noted that the characteristic distance of the soil improvement day represents the content of various heavy metals in the samples on the soil improvement day. The larger the characteristic distance, the greater the content of various heavy metals in the corresponding samples. The larger the value is, the more heavy metals the tea oil tree absorbs from the soil, and the more heavy metals that are not solidified in the soil. Therefore, it is more necessary to lower the pH value of the soil to solidify the heavy metals in the soil and prevent the heavy metals from being absorbed by the tea oil tree.

[0068] Thus, the primary pH reduction value on each soil improvement day was obtained.

[0069] Step S004: Obtain the change fitting line of the soil improvement date according to the characteristic distance of each day between adjacent soil improvement dates; according to the change fitting line of the soil improvement date, correct the primary pH value reduction of the soil improvement date to obtain the pH value reduction of the soil improvement date.

[0070] It should be noted that during the process of improving the soil quality of the oil tea garden, if the pH value of the soil is suddenly changed significantly, it will damage the root system of the oil tea tree and affect the absorption of nutrients by the oil tea tree. Moreover, the microbial community in the soil will also change accordingly, resulting in a decrease in the activity of beneficial microorganisms in the soil, which will further endanger the growth and health of the oil tea tree. Also, due to the differences in the ability of plants to absorb heavy metals in the soil during their growth, in order to avoid excessive adjustment of the soil pH value and cause adverse effects on the growth of plants, the adjustment of the pH value should be corrected.

[0071] Preferably, in a specific embodiment of the present invention, for any soil improvement date, the date between the previous soil improvement date and the current soil improvement date of the soil improvement date is recorded as the change date (the change date includes the soil improvement date and the previous soil improvement date of the soil improvement date), and the characteristic distance of each change date is obtained; since the process of obtaining the characteristic distance of the change date is the same as that of obtaining the characteristic distance of the soil improvement date, it will not be elaborated in this embodiment.

[0072] Further, taking the date as the horizontal axis and the characteristic distance of the change date as the vertical axis, a rectangular coordinate system is constructed. Each change date is used as a coordinate point and placed in the rectangular coordinate system to obtain the change scatter plot of the soil improvement date; the least squares method is used to perform linear fitting on the change scatter plot of the soil improvement date to obtain the change fitting line of the soil improvement date; since the least squares method is a well-known existing technology, it will not be elaborated in this embodiment.

[0073] It should be further noted that the change fitting line of the soil improvement date represents the change in the content of various heavy metals in the soil every day during the period between two adjacent soil improvement dates. When the slope of the fitting line is smaller, it indicates that the oil tea tree absorbs more heavy metals during this period, which will more endanger the health of the oil tea tree. Therefore, the greater the reduction amplitude of its pH value should be. Thus, the pH value reduction of the soil improvement date can be obtained based on this.

[0074] Preferably, in a specific embodiment of the present invention, for any soil improvement date, the primary pH value reduction of the soil improvement date is corrected according to the root mean square error of the change fitting line of the soil improvement date and the slope of the change fitting line of the soil improvement date to obtain the pH value reduction of the soil improvement date. The specific calculation formula is:

[0075]

[0076] In the formula, represents the pH value reduction of the soil improvement day; represents the primary pH value reduction of the soil improvement day; represents the root mean square error of the change fitting line on the soil improvement day; represents the slope of the change fitting line on the soil improvement day; represents the sigmoid function, which is used for normalization processing in this embodiment.

[0077] It should be further noted that the larger the value of the root mean square error of the change fitting line on the soil improvement day, the greater the difference in the amount of heavy metals absorbed by the oil tea tree from the soil every day, that is, it indicates that the oil tea tree has been harmed by heavy metals in the soil and cannot stably absorb energy from the soil. Therefore, the larger the root mean square error of the change fitting line on the soil improvement day, the greater the increase in the pH value reduction should be; and because the smaller the slope of the change fitting line on the soil improvement day, the greater the increase in the pH value reduction should be; therefore the larger the value of , the greater the increase in the pH value reduction should be.

[0078] Furthermore, a soil improvement termination threshold is preset , The specific value of can be set according to the actual situation and is not strictly required in this embodiment. In this embodiment, it is described with When it comes to the th soil improvement day, the improvement of the oil tea garden soil is completed, and the heavy metals in the oil tea garden soil are solidified.

[0079] Another embodiment of the present invention provides an oil tea tree heavy metal pollution non-destructive detection system, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements an oil tea tree heavy metal pollution non-destructive detection method in steps S001 to S004.

[0080] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A nondestructive detection method for heavy metal pollution in oil tea trees, characterized in that: The method comprises the following steps: Obtain the daily sample spectra of the oil tea garden and select several soil improvement days from them; According to the daily sample spectra, the content of each heavy metal in the daily samples is obtained; According to the content of each heavy metal in the daily sample and the content of each heavy metal in all previous samples, the daily sample space is constructed to obtain several clusters in the daily sample space; according to the several clusters in the sample space of each soil improvement day, the characteristic distance of each soil improvement day is obtained; according to the characteristic distances of adjacent soil improvement days, the primary pH value reduction value of the soil improvement day is obtained; According to the daily characteristic distances between adjacent soil improvement days, a fitting straight line of changes on the soil improvement day is obtained; according to the fitting straight line of changes on the soil improvement day, the primary pH value reduction value on the soil improvement day is corrected to obtain the pH value reduction value on the soil improvement day; The specific calculation formula for obtaining the primary pH value reduction value on the soil improvement day according to the characteristic distance between adjacent soil improvement days is as follows: In the formula, Indicates Primary pH reduction per soil improvement day; Indicates pH reduction value per soil improvement day; Indicates characteristic distance of soil improvement days; Indicates characteristic distance of soil improvement days; Indicates characteristic distance of soil improvement days; Indicates characteristic distance of soil improvement days; Indicates The differences in characteristic distances of all adjacent soil improvement days before the soil improvement day are traversed, and the maximum value function is taken; The specific method of obtaining the change fitting straight line of the soil improvement day according to the daily characteristic distance between adjacent soil improvement days includes: For any soil improvement day, the date between the last soil improvement day and the soil improvement day is recorded as a change day, and the characteristic distance of each change day is obtained; A rectangular coordinate system is constructed with the date as the horizontal axis and the characteristic distance of the change day as the vertical axis, and each change day is taken as a coordinate point and placed in the rectangular coordinate system to obtain a scatter plot of the change of the soil improvement day; a linear fitting is performed on the scatter plot of the change of the soil improvement day using the least squares method to obtain a fitting straight line of the change of the soil improvement day; The method of fitting a straight line according to the change of the soil improvement day, correcting the primary pH value reduction value on the soil improvement day, and obtaining the pH value reduction value on the soil improvement day includes the following specific methods: For any soil improvement day, the primary pH value reduction value on the soil improvement day is corrected according to the root mean square error of the change fitting line on the soil improvement day and the slope of the change fitting line on the soil improvement day to obtain the pH value reduction value on the soil improvement day. The specific calculation formula is: In the formula, represents the pH reduction value on the soil improvement day; represents the primary pH reduction on the soil improvement day; The root mean square error of the fitted straight line representing the variation of the soil improvement day; The slope of the fitted straight line representing the change of the soil improvement day; Represents the sigmoid function.

2. According to claim 1, a nondestructive detection method for heavy metal pollution in oil tea trees is characterized in that: The specific method of obtaining the sample spectrum of the oil tea garden every day and selecting several soil improvement days therefrom includes: For Day, randomly selected in the tea garden sampling points, and samples were collected at each sampling point in the oil tea garden. The collected soil was placed in a fume hood to air dry, and the air-dried soil was ground with a mortar to obtain soil powder. The purpose sieve filters the soil powder to obtain the The samples to be tested on the day are detected by spectrometer. The samples to be tested on the day are obtained Sample spectrum of the day; , as well as They are the preset number of sampling points, soil collection quality, and sieve specifications; Preset a soil improvement cycle , on the first day and every The date of the day is recorded as the soil improvement day.

3. According to claim 1, a nondestructive detection method for heavy metal pollution in oil tea trees is characterized in that: The specific method of obtaining the content of each heavy metal in the sample every day according to the sample spectrum every day is as follows: For In the sample of the day heavy metal content; obtain the The characteristic band of heavy metals and set the The content limit of the heavy metals in the oil tea garden soil The spectrum when the heavy metal content is at the content limit is recorded as the reference spectrum. The curve segment of the characteristic wave band of the heavy metal is recorded as the reference curve segment; In the sample spectrum of the day, The curve segment of the characteristic wave band of the heavy metal is combined with the reference curve segment and the content limit to obtain the In the sample of the day Heavy metal content.

4. According to claim 3, a nondestructive detection method for heavy metal pollution in oil tea trees is characterized in that: The acquisition In the sample of the day The specific calculation formula for the content of heavy metals is as follows: In the formula, Indicates In the sample of the day Heavy metal content; Indicates Content limits of various heavy metals; Indicates In the sample spectrum of the day, The definite integral of the curve segment of the characteristic band of the heavy metal; represents the definite integral of the reference curve segment; represents the hyperbolic tangent function.

5. According to claim 1, a nondestructive detection method for heavy metal pollution in oil tea trees is characterized in that: The method of constructing a daily sample space according to the content of each heavy metal in the daily sample and the content of each heavy metal in all previous samples, and obtaining several clusters in the daily sample space, includes the following specific methods: Construct an N-dimensional sample space, where N is the number of heavy metal types; Day, will Heaven and Earth The samples before the day are recorded as target samples. According to the content of each heavy metal in each target sample, all target samples are placed in the sample space, and each target sample is used as a data point in the sample space to obtain the first Sample space of day; Using DBSCAN clustering algorithm The data points in the sample space of the first day are clustered, and the distance metric is the Euclidean distance between the data points. Several clusters in the sample space of the day.

6. A nondestructive detection method for heavy metal pollution in oil tea trees according to claim 1, characterized in that: The specific method of obtaining the characteristic distance of each soil improvement day according to the plurality of clusters in the sample space of each soil improvement day includes: For Soil Improvement Day The sample space of the soil improvement day contains The cluster of data points corresponding to the soil improvement day is recorded as The target clusters in the sample space of the soil improvement day are The distance between the target cluster center and the origin of the sample space in the sample space of the soil improvement day is recorded as Characteristic distance of soil improvement days.

7. A nondestructive detection system for heavy metal pollution in oil tea trees, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is executed by a processor, the steps of a nondestructive detection method for heavy metal pollution in oil tea trees as described in any one of claims 1 to 6 are implemented.

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