High-phreatic-water-level coal subsidence area slope vegetation configuration method based on ecological restoration effect

Abstract

The invention discloses a high-water-level coal subsidence area slope vegetation configuration method based on an ecological restoration effect, and the method comprises the steps: constructing a soil-microorganism-water body three-dimensional measurement system, employing a vector normalization algorithm to eliminate the dimensional difference through a multi-scale coupling evaluation mechanism, and obtaining the vegetation of a slope in a high-water-level coal subsidence area. The method comprises the following steps: calculating a soil nutrient retention rate (RSFI), calculating a soil bacterial diversity growth rate # imgabs0 # and a downstream ponding area water eutrophication index reduction rate (RTLI) based on a 16SrRNA sequencing result, generating a vegetation ecological restoration index (ERI), and automatically screening a vegetation configuration scheme with soil immobilization, microorganism growth promotion and water quality purification functions. Multi-parameter collaborative quantitative evaluation of the ecological restoration effect of the coal mining subsidence area is achieved, decision support with space-time dynamic adaptability is provided for vegetation spatial layout, and systematicness and accuracy of ecological restoration are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological restoration of coal mining subsidence areas, and specifically, to a method for vegetation configuration on slopes in high water table coal subsidence areas based on the ecological restoration effect. Background Art

[0002] In high water table mining areas, underground mining will cause surface subsidence and water accumulation. There are a large number of slopes around the water accumulation area. Due to the action of gravity, during the concentrated precipitation period in the flood season, the surface soil is severely eroded by water, and the organic matter on the slopes is severely lost with the surface runoff. On the one hand, this leads to the attenuation of the soil's fertilizer and water retention performance on the slopes and a serious decline in the land output capacity. On the other hand, due to a large amount of surface runoff from the slopes flowing into the water body of the water accumulation area, the total phosphorus (TP) and total nitrogen (TN) in the water accumulation area continue to accumulate, and the water body is severely eutrophicated, and the ecology of the water body in the water accumulation area is severely damaged.

[0003] To avoid serious ecological damage, vegetation restoration is an effective method to block, filter, and absorb the soil nutrients on the slopes of coal mining subsidence areas, and it has low cost, is easy to maintain, and uses local materials. However, for different vegetation layout patterns, such as different vegetation combinations and different vegetation planting densities, there are significant differences in the achieved ecological restoration effects. When evaluating the vegetation restoration effect, only the fixation efficiency of vegetation on the soil organic matter (SOC) in the subsidence area slopes is considered, and the bacterial diversity of the slope soil and the degree of eutrophication of the water body in the water accumulation area are not evaluated simultaneously, resulting in a single vegetation configuration on the slopes of coal mining subsidence areas with high water table, and it is necessary to optimize the vegetation configuration for the slopes in high water table coal mining subsidence areas. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for vegetation configuration on slopes in high water table coal subsidence areas based on the ecological restoration effect to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A method for vegetation configuration on slopes in high water table coal subsidence areas based on the ecological restoration effect, including the following steps:

[0006] S1. Set a slope top sample area and a slope bottom sample area in each vegetation configuration unit of the target slope. Set multiple sample plots in each sample area, collect samples in each sample plot and mix them to form a soil sample, measure the contents of soil organic matter, soil available phosphorus, available nitrogen, and available potassium, and analyze the soil bacterial characteristics through 16S rRNA;

[0007] S2. Collect overlying water samples in the downstream water accumulation area corresponding to each vegetation configuration slope surface, and at the same time collect overlying water in the downstream water accumulation area corresponding to the slope surface without vegetation restoration as a control sample, and measure the chlorophyll a, total phosphorus, total nitrogen, transparency, and permanganate index of the samples;

[0008] S3. Use the vector normalization algorithm to perform dimensionality elimination processing on the measured organic matter, available phosphorus, available nitrogen, and available potassium contents in the soil, construct a standardized data set, calculate the soil nutrient index, and establish a model for the soil nutrient retention rate (R SFI );

[0009] S4. Quantify the soil bacterial diversity through the Shannon index algorithm and establish an evaluation model for the growth rate of soil bacterial diversity ;

[0010] S5. According to the water quality indicators measured in step S2, establish an evaluation model for the eutrophication of the water body in the downstream waterlogging area;

[0011] S6. Integrate the model of the soil nutrient retention rate (R SFI ), the evaluation model of the growth rate of soil bacterial diversity and the evaluation model of the eutrophication of the water body in the downstream waterlogging area to construct a vegetation ecological restoration index (ERI) and screen the optimal vegetation configuration mode.

[0012] Preferably, in the step S3, the method for normalizing the measured values is as follows:

[0013]

[0014] where X norm is the normalized value, X i is the measured value, and n is the number of samples.

[0015] Preferably, in the step S3, the method for calculating the soil nutrient index (SFI) is as follows:

[0016] SFI = w1 × SOC norm + w2 × AP norm + w3 × AK norm + w4 × AN normSFI ,

[0017] where SFI is the soil nutrient index (SFI), w1, w2, w3, and w4 are the weight coefficients of each index, SOC norm is the normalized soil organic matter (SOC) value, AP norm is the normalized available phosphorus (AP) value of the soil, AK norm is the normalized available nitrogen (AN) value, and AK norm is the normalized available potassium (AK) value.

[0018] Preferably, in the step S3, the method for establishing a model for the soil nutrient retention rate of the slope is as follows:

[0019] RSFI =(SFI b -SFI t ) / SFI t ×100,

[0020] wherein, SFI t and SFI b respectively represent the soil fertility index (SFI) at the top and bottom of the slope, and R SFI represents the retention rate of soil nutrients by vegetation on the slope.

[0021] Preferably, in the step S4, the method for quantifying soil bacterial diversity by the Shannon index algorithm is:

[0022]

[0023] wherein, H shannon represents the soil bacterial index, Sobs represents the number of OTUs actually observed, m i represents the number of sequences of the i-th OTU, and M represents the total number of sequences.

[0024] Preferably, in the step S4, the method for establishing a model for the growth rate of soil bacterial diversity is:

[0025]

[0026] In the formula, represents the growth rate of soil bacterial diversity from the top to the bottom of the slope, H shannont represents the soil fertility index at the top of the slope, and H shannonb represents the soil fertility index at the bottom of the slope.

[0027] Preferably, in the step S5, the method for establishing an evaluation model for eutrophication of water bodies in the downstream waterlogging area includes:

[0028] S51. Calculate the comprehensive trophic state index (TLI(∑)) according to the water quality indicators measured in step S2

[0029]

[0030] wherein, TLI(∑) represents the comprehensive trophic state index; w z represents the relevant weight of the trophic state index of the z-th parameter; TLI(z) represents the trophic state index of the z-th parameter;

[0031] S52. Calculate the reduction rate of the eutrophication index of the water body in the downstream waterlogging area according to the comprehensive trophic state index (TLI(∑)):

[0032] R TLI =(TLI 对照-TLI 实测 ) / TLI 对照 × 100,

[0033] wherein, TLI 对照 and TLI 实测 respectively represent the eutrophication index of the water body in the downstream water accumulation area corresponding to the control slope and the eutrophication index of the water body in the water accumulation area corresponding to the vegetation restoration slope, and P TLI represents the reduction rate of the eutrophication index of the water body.

[0034] Preferably, the calculation formula for the normalized correlation weight of the z-th parameter in step S7 is:

[0035]

[0036] wherein, r iz represents the correlation coefficient between the z-th parameter and the reference parameter chla; m represents the number of evaluation parameters.

[0037] Preferably, in the said step S6, the method for constructing the vegetation ecological restoration index (ERI) is:

[0038]

[0039] wherein, a1, a2, and a3 respectively represent the weights of the slope soil nutrient retention rate, the growth rate of soil bacterial diversity, and the reduction rate of the eutrophication index of the water body.

[0040] Preferably, in the said S6, the vegetation ecological restoration index (ERI) with the maximum screening result value is the optimal vegetation configuration mode.

[0041] The method for slope vegetation configuration in high water table coal subsidence areas based on ecological restoration effects proposed by the present invention, through a multi-scale coupling evaluation mechanism, uses the vector normalization algorithm to eliminate the dimension difference, calculates the soil nutrient retention rate (R SFI ), calculates the growth rate of soil bacterial diversity based on the 16S rRNA sequencing results and the reduction rate of the eutrophication index of the downstream water accumulation area (R TLI ), generates the vegetation ecological restoration index (ERI), taking into account the role of vegetation in retaining soil nutrients, promoting the improvement of soil microbial diversity, and thus improving the water quality of the water accumulation area, so as to be able to more comprehensively screen the optimal layout mode of slope vegetation in high water table coal mining subsidence areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a flowchart of the method for slope vegetation configuration in high water table coal subsidence areas based on ecological restoration effects according to an embodiment of the present invention;

[0043] Figure 2Schematic diagram of slope layout of sample plots in the method for slope vegetation configuration in coal subsidence areas with high phreatic water level based on ecological restoration effect in the embodiments of the present invention. Detailed implementation manners

[0044] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] Please refer to Figure 1 - Figure 2 , embodiments of the present invention provide a method for slope vegetation configuration in coal subsidence areas with high phreatic water level based on ecological restoration effect, including the following steps:

[0046] As Figure 2 shown, in step S1, on the slope of each vegetation layout in the coal mining subsidence area with high phreatic water level, two sample plots, namely the slope top and the slope bottom, are respectively arranged. Three sample sites are arranged in each sample plot, and three soil sub-samples of 0-15 cm are respectively collected in each sample site and mixed into a soil sample to analyze the contents of soil organic matter (SOC), available phosphorus (AP), available nitrogen (AN), and available potassium (AK) in the soil. At the same time, the 16S rRNA method is used to determine the soil bacterial characteristics.

[0047] In step S2, overlying water samples of 0-20 cm are collected from the downstream water accumulation areas corresponding to the slopes of each vegetation configuration, and at the same time, overlying water is collected from the downstream water accumulation areas corresponding to the slopes without vegetation restoration as a control sample to measure five indexes of the sample, namely chlorophyll a (chla), total phosphorus (TP), total nitrogen (TN), transparency (SD), and permanganate index (CODmn). The layout of the sample sites is as Figure 2 shown.

[0048] In step S3, due to the different dimensions of each index, the vector normalization algorithm is used to eliminate the dimension of the measured contents of organic matter, available phosphorus (AP), available nitrogen (AN), and available potassium (AK) in the soil, construct a standardized data set, calculate the soil nutrient index (SFI), and establish a model for the soil nutrient retention rate (R SFI ) based on this index.

[0049] Specifically, due to the different dimensions of each index, the vector normalization method is used to normalize the contents of soil organic matter (SOC), available phosphorus (AP), available nitrogen (AN), and available potassium (AK) measured in step S1:

[0050]

[0051] Among them, X norm is the normalized value, X i is the measured value, and n is the number of samples;

[0052] In one embodiment, the method for calculating the soil nutrient index (SFI) is as follows:

[0053] SFI = w1 × SOC norm + w2 × AP norm + w3 × AK norm + w4 × AN normSFI

[0054] (Formula 2)

[0055] Among them, SFI is the soil nutrient index (SFI), w1, w2, w3, and w4 are the weight coefficients of each index, and SOC norm is the normalized soil organic matter (SOC) value, AP norm is the normalized available phosphorus (AP) value of the soil, AK norm is the normalized available nitrogen (AN) value, and AK norm is the normalized available potassium (AK) value;

[0056] In one embodiment, the method for calculating the soil nutrient retention rate of the sloping land is as follows:

[0057] R SFI = (SFI b - SFI t ) / SFI t × 100 (Formula 3)

[0058] Among them, SFI t and SFI b respectively represent the soil nutrient index (SFI) at the top and bottom of the slope, and R SFI represents the soil nutrient retention rate of the slope by vegetation;

[0059] In step S4, according to the 16S rRNA sequencing results of the soil bacteria on the sloping land in step S1, the Shannon index of the soil bacteria is calculated.

[0060] Among them, the calculation formula of the Shannon index of the soil bacteria is as follows:

[0061]

[0062] Among them, H shannon represents the soil bacteria index, Sobs represents the number of OTUs actually observed, and m iThe number of sequences of the i-th OTU is denoted as [[ID=]], and M represents the total number of sequences. The number of OTUs refers to the result of clustering sequences with 97% similarity in microbial diversity analysis.

[0063] Based on the obtained Shannon index of soil bacteria, calculate the growth rate of soil bacterial diversity.

[0064]

[0065] Among them, represents the growth rate of soil bacterial diversity from the top to the bottom of the slope, and H shannont represents the soil nutrient index at the top of the slope, and H shannonb represents the soil nutrient index at the bottom of the slope.

[0066] In one embodiment, based on the water quality indicators measured in step S2, establish an evaluation model for water eutrophication in the downstream water accumulation area.

[0067] Specifically, according to the chlorophyll a (chla), total phosphorus (TP), total nitrogen (TN), transparency (SD), and permanganate index (CODmn) in the overlying water sample in step S1, calculate the degree of water eutrophication of the slope land. According to the preferred embodiment, the comprehensive trophic state index method (TLI(∑)) is used to calculate the degree of water eutrophication.

[0068]

[0069] In the formula, TLI(∑) represents the comprehensive trophic state index; w z represents the relevant weight of the trophic state index of the z-th parameter; TLI(z) represents the trophic state index of the z-th parameter.

[0070] Among them, when taking chlorophyll a (chla) as the reference parameter, the calculation formula for the normalized relevant weight of the z-th parameter is:

[0071]

[0072] Among them, r iz represents the correlation coefficient between the z-th parameter and the reference parameter chlorophyll a (chla), and m represents the number of evaluation parameters. The correlation relationships r iz and r iz 2 are shown in Table 1.

[0073] Table 1: Correlation relationships r iz and riz 2 value;

[0074] parameter chla TP TN SD <![CDATA[COD mn > <![CDATA[r iz > 1 0.84 0.82 -0.83 0.83 <![CDATA[r iz 2 > 1 0.7056 0.6724 0.6889 0.6889

[0075] Among them, the nutritional status index of each item is calculated as follows:

[0076] TLI(chla) = 10 × (2.5 + 1.086 ln chla)

[0077] TLI(TP) = 10 × (9.436 + 1.624 ln TP)

[0078] TLI(TN) = 10 × (5.453 + 1.694 ln TN)

[0079] TLI(SD) = 10 × (5.118 - 1.94 ln SD)

[0080] TLI(CODmn) = 10 × (0.109 + 2.661 ln CODmn)

[0081] Among them, the unit of chlorophyll a (chla) is mg / m 3 , and the unit of transparency (SD) is m; the units of other indicators are all mg / L.

[0082] In one embodiment, according to the comprehensive nutritional status index (TLI(∑)) in Formula 6 above, calculate the reduction rate (R TLI ) of the water body eutrophication index, and the specific formula is as follows:

[0083] R TLI = (TLI 对照 - TLI 实测 ) / TLI 对照 × 100 (Formula 7)

[0084] Among them, TLI 对照 and TLI 实测 respectively represent the water body eutrophication index of the water storage area corresponding to the control slope and the water body eutrophication index of the water storage area corresponding to the vegetation restoration slope, and R TLI represents the reduction rate of the water body eutrophication index.

[0085] Combining the above slope soil nutrient retention rate (R SFI ), the growth rate of soil bacterial diversity and the reduction rate (R TLI ) of the water body eutrophication index, comprehensively evaluate the vegetation ecological restoration index (ERI) from three aspects, and screen out the optimal vegetation layout mode for the slopes in the high water table coal mining subsidence area.

[0086] In one embodiment, the calculation formula of the vegetation ecological restoration index (ERI) is as follows:

[0087]

[0088] Among them, a1, a2, and a3 respectively represent the weights of the slope soil nutrient retention rate, the growth rate of soil bacterial diversity, and the reduction rate of water body eutrophication index. In this embodiment, a1, a2, and a3 are 0.4, 0.3, and 0.3 respectively.

[0089] The larger the vegetation ecological restoration index (ERI), the better the vegetation restoration effect. According to the vegetation ecological restoration index (ERI), the optimal slope vegetation layout pattern is screened.

[0090] The embodiment of the present invention discloses a slope vegetation configuration method for high water table coal subsidence areas based on the ecological restoration effect. By constructing a "soil-microorganism-water body" three-dimensional measurement system, the limitation of single-index evaluation is changed. This method uses a multi-scale coupling evaluation mechanism and applies the vector normalization algorithm to eliminate the dimension difference, calculates the soil nutrient retention rate (R SFI ), calculates the growth rate of soil bacterial diversity based on the 16S rRNA sequencing results and the reduction rate of water body eutrophication index in the downstream waterlogging area (R TLI ), generates the vegetation ecological restoration index (ERI), automatically screens the vegetation configuration plan with the functions of soil retention, microorganism promotion, and water quality purification, realizes the multi-parameter collaborative quantitative evaluation of the ecological restoration effect in the coal mining subsidence area, provides decision support with spatio-temporal dynamic adaptability for the vegetation spatial layout, and significantly improves the systematicness and accuracy of ecological restoration.

[0091] The parts not involved in the present invention are the same as or can be implemented by the prior art. Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for slope vegetation configuration in coal subsidence areas with high phreatic levels based on the effect of ecological restoration, characterized in that, It includes the following steps: S1. Set a slope top sample area and a slope bottom sample area in each vegetation configuration unit of the target slope. Set multiple sample plots in each sample area, collect samples in each sample plot respectively and mix them to form soil samples, measure the contents of soil organic matter, available phosphorus, available nitrogen and available potassium in the soil, and analyze the characteristics of soil bacteria through 16S rRNA; S2. Collect overlying water samples in the downstream water accumulation area corresponding to each vegetation configuration slope surface, and at the same time collect overlying water in the downstream water accumulation area corresponding to the slope surface without vegetation restoration as a control sample, and measure the chlorophyll a, total phosphorus, total nitrogen, transparency and permanganate index of the sample; S3. Use the vector normalization algorithm to perform dimensionality elimination processing on the measured organic matter, available phosphorus, available nitrogen, and available potassium contents in the soil, construct a standardized data set, calculate the soil nutrient index, and establish a model for the soil nutrient retention rate (R SFI ) based on the index; S4. Quantify the soil bacterial diversity through the Shannon index algorithm and establish an evaluation model for the growth rate of soil bacterial diversity ; S5. Establish an evaluation model for water body eutrophication in the downstream water accumulation area according to the water quality indexes measured in step S2; S6. Based on the above-mentioned soil nutrient retention rate (R SFI ), the evaluation model of the growth rate of soil bacterial diversity and the evaluation model of water eutrophication in the downstream waterlogging area, construct the vegetation ecological restoration index (ERI) and screen the optimal vegetation configuration pattern.

2. The method for slope vegetation configuration in high water table coal subsidence areas based on ecological restoration effect according to claim 1, characterized in that In step S3, the method for normalizing the measured values is as follows: Among them, X norm is the normalized value, X i is the measured value, and n is the number of samples.

3. The method for slope vegetation configuration in coal subsidence areas with high phreatic levels based on the ecological restoration effect according to claim 2, characterized in that In step S3, the method for calculating the soil nutrient index is as follows: SFI = w1 × SOC norm + w2 × AP norm + w3 × AK norm + w4 × AN normSFI , Among them, SFI is the soil fertility index, and w1, w2, w3, and w4 are the weight coefficients of each index. SOC norm is the normalized soil organic matter value, AP norm is the normalized available phosphorus value of the soil, AK norm is the normalized available nitrogen value, AK norm is the normalized available potassium value.

4. The method for slope vegetation configuration in coal subsidence areas with high phreatic levels based on ecological restoration effects according to claim 3, wherein, In step S3, the method for establishing a model for the soil nutrient retention rate of the slope is as follows: R SFI = (SFI b - SFI t ) / SFI t × 100, Among them, SFI t and SFI b respectively represent the soil nutrient indices at the top and bottom of the slope, and R SFI represents the retention rate of slope soil nutrients by vegetation.

5. The method for slope vegetation configuration in coal subsidence areas with high phreatic levels based on ecological restoration effects according to claim 1, characterized in that In step S4, the method for quantifying soil bacterial diversity through the Shannon index algorithm is as follows: Among them, H shannon represents the soil bacterial index, Sobs represents the number of OTUs actually observed, and m i represents the number of sequences of the i-th OTU, and M represents the total number of sequences.

6. The method for slope vegetation configuration in high water table coal subsidence areas based on ecological restoration effect according to claim 5, characterized in that, In step S4, the method for establishing a model for the growth rate of soil bacterial diversity is as follows: Among them, represents the growth rate of soil bacterial diversity from the top to the bottom of the slope, H shannont represents the soil nutrient index at the top of the slope, H shannonb represents the soil nutrient index at the bottom of the slope.

7. The method for slope vegetation configuration in high water table coal subsidence areas based on ecological restoration effect according to claim 1, characterized in that In step S5, the method for establishing an evaluation model for water body eutrophication in the downstream water accumulation area includes: S51. Calculate the comprehensive trophic state index (TLI(∑)) according to the water quality indexes measured in step S2 Among them, TLI(∑) represents the comprehensive trophic state index; w z represents the relevant weight of the trophic state index of the z-th parameter; TLI(z) represents the trophic state index of the z-th parameter; S52. Calculate the reduction rate of the water body eutrophication index in the downstream water accumulation area according to the comprehensive trophic state index (TLI(∑)); R TLI = (TLI 对照 - TLI 实测 ) / TLI 对照 × 100, Among them, TLI 对照 and TLI 实测 respectively represent the eutrophication index of the water body in the downstream water accumulation area corresponding to the control slope surface and the eutrophication index of the water body in the water accumulation area corresponding to the vegetation restoration slope surface. R TLI represents the reduction rate of the eutrophication index of the water body.

8. The method for slope vegetation configuration in coal subsidence areas with high phreatic levels based on ecological restoration effects according to claim 7, characterized in that, The calculation formula for the relevant weight of normalizing the z-th parameter in step S7 is: where r iz represents the correlation coefficient between the z-th parameter and the reference parameter chla; m represents the number of evaluation parameters.

9. The method for slope vegetation configuration in coal subsidence areas with high phreatic levels based on ecological restoration effects according to claim 1, wherein In step S6, the method for constructing the vegetation ecological restoration index (ERI) is as follows: Among them, a1, a2, and a3 respectively represent the weights of the soil nutrient retention rate of the slope, the growth rate of soil bacterial diversity, and the reduction rate of the water body eutrophication index.

10. The method for slope vegetation configuration in coal subsidence areas with high phreatic levels based on ecological restoration effects according to claim 9, characterized in that: In S6, the vegetation ecological restoration index (ERI) with the maximum screening result value is the optimal vegetation configuration mode.

Images