Method for detecting correlation between quality of tetrastigma hemsleyanum and soil components

Abstract

This invention discloses a method for detecting the correlation between the quality of *Trifolium repens* and soil composition, comprising: pre-treating *Trifolium repens* and planting soil under different planting conditions to obtain corresponding test solutions; detecting the content of chemical components in the *Trifolium repens* test solutions and detecting the content of essential elements and trace elements in the planting soil test solutions; determining the weight of corresponding items based on the content of chemical components under corresponding planting conditions using the entropy weight method; evaluating the quality of *Trifolium repens* using the superior-inferior solution distance method based on the weights of each item under corresponding planting conditions; and determining the correlation degree between the quality of *Trifolium repens* and soil composition using the grey relational analysis method. When the correlation degree exceeds a preset threshold, the quality of *Trifolium repens* is considered to have a high correlation with the corresponding elements in the soil composition. This method has high detection accuracy and helps to improve the planting quality of *Trifolium repens*.

Description

Technical Field

[0001] This invention belongs to the field of analytical testing technology, specifically relating to a method for detecting the correlation between the quality of *Trifolium repens* and soil composition. Background Technology

[0002] San Ye Qing is the tuberous root of Tetrastigma hemsleyanum Diels et Gilg, a plant in the Vitaceae family. However, the quality of San Ye Qing medicinal materials on the market varies greatly, and the composition of the soil used for cultivation is closely related to the quality of the medicinal materials.

[0003] Soil total nitrogen content has different regulatory effects on the accumulation of effective components in various Chinese medicinal herbs. Soil total phosphorus is beneficial for the accumulation of total flavonoids in Chinese medicinal herbs. Furthermore, changes in soil total phosphorus content affect soil physicochemical properties, thus indirectly influencing the growth environment of Chinese medicinal herbs. Applying potassium fertilizer can improve the medicinal quality and yield of Chinese medicinal herbs, while also promoting the growth of rhizome herbs such as Corydalis yanhusuo and Ophiopogon japonicus. In addition, the available potassium content in the soil is closely related to the medicinal components of Chinese medicinal herbs. An appropriate supply of ammonium nitrogen can promote the growth of Chinese medicinal herbs. Ammonium nitrogen indirectly promotes the accumulation of medicinal components by affecting the activity of plant metabolic enzymes. Excessive application may lead to soil acidification, inhibiting nitrification and thus affecting the absorption of nitrate nitrogen by plants. In conclusion, rational fertilization and soil management are key measures to improve the quality of Chinese medicinal herbs.

[0004] Geographical location and soil type significantly affect the solubility of copper and iron in the soil, as well as the plant's ability to absorb these important micronutrients. The accumulation of secondary metabolites in medicinal herbs is closely related to soil nutrients. This study aims to determine the quality of *Tripterygium wilfordii* under different substrate ratios and the content of essential soil elements. By considering the impact of various elements in the planting substrate on the quality of *Tripterygium wilfordii* and establishing their correlation, this research is of great significance in preventing inconsistent quality in the cultivation of this medicinal herb. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned problems by proposing a detection method for the correlation between the quality of Trifoliate Oryza sativa and soil composition. This method has high detection accuracy and helps to improve the planting quality of Trifoliate Oryza sativa.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The present invention proposes a method for detecting the correlation between the quality of *Trifolium repens* and soil composition, comprising the following steps:

[0008] S1. Pretreatment was performed on *Trifolium repens* and planting soil under different planting conditions to obtain the corresponding test solutions;

[0009] S2. The chemical composition of the test solution of *Trifolium repens* was tested, and the content of essential elements and trace elements in the test solution of the planting soil was tested.

[0010] S3. Determine the weight of each item based on the content of chemical components under the corresponding planting conditions using the entropy weight method.

[0011] S4. Evaluate the quality of *Trifolium repens* using the superior-inferiority distance method based on the weights of each item under the corresponding planting conditions.

[0012] S5. Using the yield of *Trifolium repens* under the best planting conditions and the content of the top K items with the highest weight in chemical composition as the mother sequence, and the content of essential elements and trace elements in the corresponding planting soil as the comparison sequence, the grey relational analysis method is used to determine the correlation between the quality of *Trifolium repens* and soil composition. When the correlation exceeds the preset threshold, it is considered that the quality of *Trifolium repens* is highly correlated with the corresponding elements in the soil composition.

[0013] Preferably, the chemical components include extracts, total flavonoids, total polysaccharides, catechins, epicatechins, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside, essential elements include total nitrogen, total phosphorus, available potassium and ammonium nitrogen, and trace elements include iron and copper.

[0014] Preferably, the content of the leachate is determined by reflux extraction, the content of total flavonoids, total polysaccharides, total nitrogen, total phosphorus, available potassium, ammonium nitrogen, iron and copper is determined by ultraviolet-visible spectrophotometry, and the content of catechin, epicatechin, osmanthus glycoside, astragaloside, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside is determined by high performance liquid chromatography.

[0015] Preferably, the content detection of leachate is as follows:

[0016] Take 10-30 ml of the test solution of the leachate and place it in an evaporating dish dried to constant weight. Evaporate to dryness in a water bath at 90℃-100℃, then dry in an electric hot air drying oven at 100℃-110℃ for 3 hours. Cool in a desiccator for 0.5-1.0 hours, and weigh the dried product to obtain the content of leachate in the test solution, expressed as a percentage (%). M J C represents the content of leachate in the test solution. J β is the weight of the dried product. J G is the first dilution factor.J W is the weight of the sample of leachate. J The moisture content of the test sample of the leachate is expressed as %, and the average content of the leachate in the test solution of all leachates under the corresponding planting conditions is taken as the content of the leachate under the current planting conditions.

[0017] The total flavonoid content was determined as follows:

[0018] Weigh 5-15 mg of rutin reference standard, add 5-8 ml of 70%-100% methanol, dissolve by sonication, cool to room temperature, and then add 70%-100% methanol to the 10 ml mark of the volumetric flask. Shake well to obtain the rutin reference standard solution. Measure 0 ml, 0.1 ml, 0.2 ml, 0.4 ml, 0.7 ml, and 1.0 ml of the rutin reference standard solution, respectively, and add water to make up to 1 ml. Place the rutin reference standard solution and 0.5 ml-2 ml of the total flavonoid test solution into separate volumetric flasks. Add 200 μL-500 μL of 5% NaNO2 to each volumetric flask, shake well, and let stand for 5-10 min; add 200 μL-500 μL of 10% Al(NO3)3, shake well, and let stand for 5-10 min; add 2 ml-5 ml of 4% NaOH, shake well, and let stand for 20-40 min. Add water to the volumetric flask to the 10ml mark, shake well and let stand for 10-20 minutes to obtain the reagent for the corresponding rutin reference solution. Use a UV-Vis spectrophotometer to detect the absorbance. Based on the absorbance and concentration of different rutin reference solutions, form a linear regression equation for total flavonoids. Then, substitute the absorbance of the test solution of total flavonoids into the linear regression equation of total flavonoids to calculate the concentration of total flavonoids in the test solution. Multiply by the second dilution factor to obtain the content of total flavonoids in the test solution. The average content of total flavonoids in all test solutions of total flavonoids under the corresponding planting conditions is taken as the content of total flavonoids under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 490 nm-520 nm.

[0019] The total polysaccharide content was determined as follows:

[0020] Take 0 μL, 25 μL, 50 μL, 100 μL, 200 μL, and 400 μL of glucose reference standard, respectively, and add water to bring the volume to 0.4 ml–1 ml. Place the glucose reference standard and 0.4 ml–1 ml of total polysaccharide test solution into separate glass test tubes. Add 1 ml–2 ml of 5% phenol solution and 3 ml–7 ml of 90%–98% concentrated sulfuric acid to each test tube sequentially. Mix well and react in a boiling water bath for 30–60 minutes. Allow to cool to room temperature, and then take 1.5 ml–2 ml of the supernatant. ml was added to a quartz cuvette, and the absorbance was measured using a UV-Vis spectrophotometer. A linear regression equation for total polysaccharides was formed based on the absorbance and concentration of different glucose standards. The absorbance of the total polysaccharide test solution was then substituted into the linear regression equation to calculate the concentration of total polysaccharides in the test solution. This concentration was then multiplied by the third dilution factor to obtain the total polysaccharide content in the test solution. The average total polysaccharide content in all test solutions under the corresponding planting conditions was taken as the total polysaccharide content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer was set to 490 nm-520 nm.

[0021] The content determination of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside is as follows:

[0022] Weigh the reference standards kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside into volumetric flasks to prepare concentrations of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside at 10 μg / ml-30 μg / ml and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside at 5 μg / ml-20 μg / ml. A first mixed reference solution of μg / ml was used; a reversed-phase ODS column was employed, with isocratic elution of the first mixed reference solution and the test solutions of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside. Mobile phase A: acetonitrile; mobile phase B: 0.085% phosphoric acid aqueous solution, with acetonitrile:0.085% phosphoric acid aqueous solution = 12:88; detection wavelength: 348 nm; flow rate: 1.0 μg / ml. The column flow rate was set at 25℃-35℃. Based on the isocratic elution results, the contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside in the corresponding test solutions were calculated. The contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside in all corresponding test solutions under the corresponding planting conditions were also calculated. The mean values ​​of 3-O-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside are respectively used as the contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside under the current planting conditions;

[0023] The content detection of catechins, epicatechins, luteolin, astragaloside, and kaempferol is as follows:

[0024] Weigh 1-2 mg each of the reference standards catechin, epicatechin, luteolin, astragaloside, and kaempferol, and place them separately in volumetric flasks. Add 4-8 ml of methanol (95% purity) and sonicate for 15-60 min, then bring the volume to 5-10 ml. Take 200-2000 μl of each and mix well to prepare a second mixed reference solution, so that the final concentrations of the standards for catechin, epicatechin, luteolin, astragaloside, and kaempferol are 15.9 μg / ml, 11.3 μg / ml, 7.2 μg / ml, 11.2 μg / ml, and 2.0 μg / ml, respectively. μg / ml; A C18 column was used, with gradient elution of the second mixed reference solution and the test solutions of catechin, epicatechin, luteolin, astragaloside, and kaempferol. Mobile phase A: acetonitrile; mobile phase B: 0.085% phosphoric acid aqueous solution. The elution gradient of acetonitrile was: 0 min–20 min, 10%–15%; 20 min–40 min, 15%–85%; 40 min–55 min, 35%–100%. The detection wavelength was 230 nm–360 nm, and the flow rate was 1.0 μg / ml. The column speed was set at 25℃-35℃. Based on the isocratic elution results, the contents of catechin, epicatechin, luteolin, astragaloside, and kaempferol in the corresponding test solutions were calculated. The average contents of catechin, epicatechin, luteolin, astragaloside, and kaempferol in all corresponding test solutions under the corresponding planting conditions were respectively used as the contents of catechin, epicatechin, luteolin, astragaloside, and kaempferol under the current planting conditions.

[0025] The detection of total nitrogen and ammonium nitrogen content is as follows:

[0026] Take 0.5 ml to 1 ml of each of the nitrogen standard solution, the total nitrogen test solution, and the ammonium nitrogen test solution, add 50 μl to 100 μl of mixed accelerator and shake well, then add 50 μl to 100 μl of indicator, shake well, let stand for 15 min to 60 min, and then add water to bring the volume to 2 ml to 5 ml. The absorbance was measured using a UV-Vis spectrophotometer. The concentration of the total nitrogen in the test solution was calculated based on the absorbance of the total nitrogen test solution, the absorbance of the nitrogen standard solution, and the concentration of the nitrogen standard solution. Similarly, the concentration of the ammonium nitrogen in the test solution was calculated based on the absorbance of the ammonium nitrogen test solution, the absorbance of the nitrogen standard solution, and the concentration of the nitrogen standard solution. The average total nitrogen content in all total nitrogen test solutions and the average ammonium nitrogen content in all ammonium nitrogen test solutions under the corresponding planting conditions were then used as the total nitrogen content and ammonium nitrogen content under the current planting conditions, respectively. The wavelength of the UV-Vis spectrophotometer was set to 410 nm-430 nm. nm, the mixing accelerator is potassium sulfate:copper sulfate:selenium = 100:10:1 dissolved in 10 times the volume of water; the indicator is methyl red:bromocresol green = 1:5 dissolved in 10 times the volume of ethanol;

[0027] The total phosphorus content was determined as follows:

[0028] Take 0.5 ml-1 ml of phosphorus standard solution and total phosphorus test solution respectively, add 50 μl-100 μl of colorimetric reagent and shake well, then add 50 μl-100 μl of 0.5% potassium antimony tartrate solution, shake well and let stand for 5 min-10 min, then add water to make up to 2 ml-5 ml, and use a UV-Vis spectrophotometer to detect the absorbance. Calculate the concentration of the total phosphorus test solution based on the absorbance of the total phosphorus test solution, the absorbance of the phosphorus standard solution and the concentration of the phosphorus standard solution. The average total phosphorus content in all total phosphorus test solutions under the corresponding planting conditions is taken as the total phosphorus content under the current planting conditions. Set the wavelength of the UV-Vis spectrophotometer to 700 nm. The colorimetric reagent is 10 g ammonium molybdate dissolved in 1 L of water and then 126 ml of 90%-98% concentrated sulfuric acid.

[0029] The detection of available potassium content is as follows:

[0030] Take 0.5 ml-1 ml of potassium standard solution and available potassium test solution respectively, add 50 μl-100 μl of 0.5 M sodium sulfate solution and shake well, then add 50 μl-100 μl of sodium tetraphenylborate solution, shake well and let stand for 5 min-10 min, then add water to make up to 2 ml-5 ml, and use a UV-Vis spectrophotometer to detect the absorbance. Calculate the concentration of available potassium test solution based on the absorbance of available potassium test solution, the absorbance of potassium standard solution and the concentration of potassium standard solution. This concentration is the available potassium content in available potassium test solution. The average available potassium content in all available potassium test solutions under the corresponding planting conditions is taken as the available potassium content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 420 nm.

[0031] The iron content testing is as follows:

[0032] Take 50 μl-100 μl of iron standard solution and iron test solution respectively, and add 50 μl-100 μl of hydroxylamine hydrochloride solution, 50 μl-200 μl of o-phenanthroline and 100 μl-500 μl of acetate-sodium acetate buffer solution in sequence for color development. After shaking and standing for 10 min-30 min, the absorbance is detected by UV-Vis spectrophotometer. The concentration of iron test solution is calculated based on the absorbance of iron test solution, the absorbance of iron standard solution and the concentration of iron standard solution. The average iron content in all iron test solutions under the corresponding planting conditions is taken as the iron content under the current planting conditions. The wavelength of UV-Vis spectrophotometer is set to 510 nm.

[0033] The copper content testing is as follows:

[0034] Take 50 μl-100 μl of copper standard solution and copper test solution respectively, and add 500 μl of 0.1 mol / L-0.5 mol / L ammonium citrate solution, 100 μl-500 μl of 0.05 mol / L-0.1 mol / L disodium EDTA solution, and 50 μl-200 μl of carbon tetrachloride in sequence. Shake well, then add 0.02 g-0.05 g of sodium diethyldithiocarbamate, shake well, and let stand for 10 min-30 min. Measure the absorbance using a UV-Vis spectrophotometer. Calculate the concentration of the copper test solution based on the absorbance of the copper test solution, the absorbance of the copper standard solution, and the concentration of the copper standard solution. This concentration is the copper content in the copper test solution. The average copper content in all copper test solutions under the corresponding planting conditions is taken as the copper content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 510 nm.

[0035] Preferably, a standard curve is generated by plotting each linear regression equation with absorbance as the ordinate and the concentration of the corresponding term as the abscissa, satisfying the following conditions: Where x is absorbance, a and b are constants, and y is the concentration of the corresponding term.

[0036] Preferably, before the soil pretreatment, the following steps are also performed:

[0037] In each experimental area, N planting bags of *Trifolium repens* were randomly selected for harvesting. During harvesting, the following operations were performed on each planting bag: a ring cut was made 10 cm above the ground, and M sampling points were set at the ring cut with a diameter of 5 cm from the center of the planting bag. After removing crop roots, insects, and stones from the soil at each sampling point, the soil was air-dried and crushed, and then passed through a 1 mm to 2 mm sieve to obtain soil samples. The samples were then packaged, preserved, and labeled.

[0038] Before pretreatment of Tripterygium wilfordii, the following operations are performed:

[0039] Pick the tuberous roots of *Trifolium repens* from the corresponding planting bags, wash and dry them, cut them into 2mm-4mm thick slices, dry them at 55℃, weigh them, and then crush them through a 50-mesh sieve. Mix the coarse powder that cannot pass through the 50-mesh sieve with the fine powder that has passed through the 50-mesh sieve. The proportion of fine powder in the mixed coarse powder and fine powder should exceed 90%, and this mixture is recorded as dry powder.

[0040] Preferably, the pretreatment is as follows:

[0041] 1) When testing leachate:

[0042] Weigh 2-4 g of the dried powder into a flat-bottomed extraction bottle, add 50-100 ml of 70% ethanol, seal tightly and weigh, let stand for 1 hour, remove the stopper and connect a reflux condenser, heat to boiling and maintain for 1 hour, cool to room temperature, remove the flat-bottomed extraction bottle, seal tightly and weigh again, replenish the lost weight with water, shake well and filter through a dry filter to obtain the test solution of the extract;

[0043] 2) When detecting total flavonoids, catechins, epicatechins, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside:

[0044] Weigh 1-2 g of the dried powder into a flat-bottomed extraction flask, add 25-50 times the volume of methanol with a concentration of 60%-90%, and weigh again. Reflux at 80℃-95℃ for 1-2 h. After cooling to room temperature, add methanol to the corresponding concentration, filter to obtain the initial test solution, which is the test solution for total flavonoids. Then, measure 20-40 ml of the filtrate of the initial test solution into an evaporating dish and concentrate it to 10-25 ml in a water bath at 80℃-100℃ to obtain the test solutions for catechin, epicatechin, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apicoside-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside.

[0045] 3) When detecting total polysaccharides:

[0046] Weigh 1-2 g of the dried powder into a flat-bottomed extraction flask, add 50-100 ml of deionized water, seal tightly, weigh, shake well, and let stand for 0.5-1.0 h. Remove the stopper and connect a reflux condenser. Reflux at 90-100℃ for 1.5-3.0 h. After cooling to room temperature, remove the flat-bottomed extraction flask, seal tightly again, and weigh. Replenish the lost weight with water, shake well, and centrifuge at 3000-4500 rpm for 5-15 min. Take 25-50 ml of the supernatant, add 1%-5% α-amylase, and hydrolyze by shaking at 35-50℃ for 10-30 min. Remove the supernatant, centrifuge at 3000-4500 rpm for 5-15 min, and take 2-10 ml of the supernatant. Add 3-5 times the amount of anhydrous ethanol, shake well, and refrigerate at 0-4℃ for at least 10 hours. Then centrifuge at 3000-4500 rpm for 10 minutes. Centrifuge at 4500 rpm for 5 min-15 min, discard the supernatant, add 5 ml-25 ml of deionized water and mix well to dissolve, then add 1 / 3 to 1 / 5 volume of chloroform-n-butanol mixed solution with chloroform:n-butanol = 4:1 and shake to remove protein for 1 h-2 h. The supernatant after protein removal is the test solution for total polysaccharides.

[0047] 4) When testing total nitrogen and total phosphorus:

[0048] Weigh 1-2 g of soil sample into an Erlenmeyer flask, add 0.5-2 ml of pure water to wet the sample, then add 4-8 ml of 90%-98% concentrated sulfuric acid and 0.5-2 ml of hydrogen peroxide. Cover the mouth of the Erlenmeyer flask with a bent-neck funnel for digestion until white fumes are emitted. After cooling to room temperature, transfer the solution to a volumetric flask, dilute to 100 ml with pure water, shake well, and let stand for 10-20 minutes. Measure 20-45 ml of the supernatant and place it in a volumetric flask, add 2-5 ml of 50% sodium hydroxide solution, dilute to 100 ml with pure water, and shake well to obtain the test solutions for total nitrogen and total phosphorus.

[0049] 5) When detecting available potassium:

[0050] Weigh 4-8 g of soil sample into an extraction bottle, add 20-40 ml of water and 1-2 g of ammonium acetate powder, shake well for 10-20 min and then filter to obtain the test solution for available potassium.

[0051] 6) When detecting ammonium nitrogen:

[0052] Weigh 4-8 g of soil sample into an extraction bottle, add 20-40 ml of water and 1-2 g of potassium chloride powder, shake well for 10-20 min and then filter to obtain the test solution for ammonium nitrogen.

[0053] 7) When testing for iron and copper:

[0054] Weigh 5-10 g of soil sample into an Erlenmeyer flask, add 10-20 ml of diethylaminetributyric acid ethylenediaminepentaacetic acid extractant, shake for 0.5-2.0 h, and then filter to obtain the test solutions for iron and copper. The diethylaminetributyric acid ethylenediaminepentaacetic acid extractant contains 0.005 mol / L of diethylenetriaminepentaacetic acid, 0.01 mol / L of calcium chloride, and 0.1 mol / L of triethanolamine.

[0055] Preferably, the quality of *Trifolium repens* is evaluated using the superior-inferior solution distance method based on the weights of each item under the corresponding planting conditions. This involves using the yield of *Trifolium repens* under the corresponding planting conditions and the content of each item in the chemical components as positive indicators. The optimal and worst matrix vectors are obtained based on the weights of each item in the chemical components. Then, the comprehensive score index S is calculated based on the positive ideal solution distance D+ and the negative ideal solution distance D- under the corresponding planting conditions, and the samples are ranked. The higher the value of the comprehensive score index S, the better the quality of *Trifolium repens* under the corresponding planting conditions.

[0056] Preferably, the different planting conditions include seven wood ash treatment groups, which are sequentially designated as group A, group B, group C, group D, group E, group F, and group G. Among them, group A has 0 kg of wood ash added and serves as the control group; group B has 1 kg of wood ash added as base fertilizer; group C has 2 kg of wood ash added as base fertilizer; group D has 1 kg of wood ash added as top dressing; group E has 2 kg of wood ash added as top dressing; group F has 0.5 kg of wood ash added as base fertilizer and 0.5 kg of top dressing; and group G has 1 kg of wood ash added as base fertilizer and 1 kg of top dressing.

[0057] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0058] This method, through the detection and correlation analysis of the chemical composition of *Tripterygium wilfordii* and the content of essential and trace elements in its planting soil, provides an accurate basis for the cultivation methods and quality control of *Tripterygium wilfordii* medicinal materials, thus contributing to the improvement of its quality. Specifically, by pretreating *Tripterygium wilfordii* and its planting soil under different planting conditions to obtain corresponding test solutions, the chemical composition of the *Tripterygium wilfordii* test solutions and the content of essential and trace elements in the planting soil test solutions are determined. The entropy weight method is used to determine the weights of corresponding items under each planting condition. Based on the weights of each item under the corresponding planting conditions, the superior-inferior solution distance method is used to evaluate the quality of *Tripterygium wilfordii*. The grey relational analysis method is used to analyze the correlation between the quality of *Tripterygium wilfordii* under the optimal planting conditions and soil composition. When the correlation exceeds a certain threshold... When setting thresholds, it was assumed that the quality of *Trifolium repens* was highly correlated with the corresponding elements in the soil composition. In particular, the detection methods for the total flavonoids and total polysaccharides in *Trifolium repens* could significantly reduce operator error and subsequent detection factors while ensuring the accuracy of the results. Furthermore, a detection method for the high content of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside in *Trifolium repens* was established, which showed high stability and accuracy. Attached Figure Description

[0059] Figure 1 This is a flowchart of the detection method for the correlation between the quality of *Trifolium repens* and soil composition according to the present invention;

[0060] Figure 2 This is a liquid chromatogram of the mixed reference solution F1 and F2 of the present invention and the test solution;

[0061] Figure 3 This is a graph showing the results of the chemical composition content detection of *Tripterygium wilfordii* according to the present invention;

[0062] Figure 4 This is a graph showing the detection results of the essential and trace element content in the planting soil of this invention. Detailed Implementation

[0063] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application.

[0065] like Figures 1-4 As shown, a method for detecting the correlation between the quality of *Trifolium repens* and soil composition includes the following steps:

[0066] Different proportions and methods of adding wood ash were used in the planting soil to create seven treatment groups (including the control group, group A). ​​These groups were: Group A (control group, 0 kg wood ash added), Group B (1 kg wood ash as base fertilizer added), Group C (2 kg wood ash as base fertilizer added), Group D (1 kg wood ash as top dressing added), Group E (2 kg wood ash as top dressing added), Group F (0.5 kg wood ash as base fertilizer + 0.5 kg top dressing added), and Group G (1 kg wood ash as base fertilizer + 1 kg top dressing added). Under conventional planting and irrigation conditions at the base, the effects of different wood ash addition ratios and methods (i.e., different planting conditions) were investigated. The selection of these groups was based on a combination of economic cost considerations and years of experience cultivating *Trifolium repens* at the base. Specifically, in this embodiment, after 6 months of seedling cultivation, when planting *Trifolium repens*, the *Trifolium repens* was divided into the aforementioned 7 wood ash treatment groups; after 3 years of planting (6 months of seedling cultivation + 2.5 years), it was harvested in winter (November to February of the following year, November 30th in this embodiment). The samples consisted of *Trifolium repens* from the 7 wood ash treatment groups and the planting soil from the corresponding planting bags.

[0067] The *Trifolium repens* and planting soil used in this embodiment were sourced from Quzhou City, Zhejiang Province, China. In each experimental area (i.e., under each planting condition), N=3 planting bags of *Trifolium repens* were randomly selected for harvesting. During harvesting, M=3 sampling points were fixed at a distance of 10 cm from the ground, with a diameter of 5 cm radiating outward from the center of the planting bag. Crop roots, insects, stones, and other debris were removed from the planting soil using tweezers, and the soil was placed in a cool, well-ventilated indoor area to air dry. The dried soil samples were then crushed with a wooden stick and passed through a 1 mm to 2 mm sieve. Three soil samples were obtained from each experimental area (corresponding to three planting bags), which were then sealed, preserved, and labeled for later use. Pick the tuberous roots of *Trifolium repens* from the corresponding planting bags, wash and dry them, cut them into 2mm-4mm thick slices, dry them at 55℃, weigh them, and then grind them through a 50-mesh sieve using a high-speed grinder. Mix the coarse powder that cannot pass through the 50-mesh sieve with the fine powder that has passed through the 50-mesh sieve (to ensure the uniformity of the dried powder), and the proportion of fine powder in the mixed coarse powder and fine powder should be 90%. Similarly, obtain 3 portions of dried powder from each experimental area.

[0068] The *Trifolium repens* and its soil under different planting conditions were pretreated to obtain corresponding test solutions. The specific pretreatment details are as follows:

[0069] 1) When testing leachate:

[0070] Weigh 2 g of the test sample (dried powder) (accurately weighed to 0.0001 g) into a flat-bottomed extraction bottle, add 50 ml of 70% ethanol, seal tightly and weigh, let stand for 1 h, remove the stopper and connect the reflux condenser, heat to boiling and maintain for 1 h, cool to room temperature, remove the flat-bottomed extraction bottle, seal tightly and weigh again, replenish the lost weight with water, shake well and filter through a dry filter to obtain the filtrate, which is the test solution of the extract.

[0071] 2) When detecting total flavonoids, catechins, epicatechins, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside:

[0072] Weigh 1 g of dried powder (accurately weighed to 0.0001 g) into a 100 ml flat-bottomed extraction flask, add 25 times the volume of 70% methanol, weigh, reflux extract at 85℃ for 1 h, cool to room temperature, add 70% methanol to make up the volume, filter to obtain the initial test solution, which is the test solution for total flavonoids; then measure 25 ml of the filtrate of the initial test solution into an evaporating dish and concentrate it in a 100℃ water bath, and make up the volume of the concentrate to 10 ml to obtain the test solutions for catechin, epicatechin, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apicoside-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside.

[0073] 3) When detecting total polysaccharides:

[0074] Weigh 1 g of dried powder (accurately weighed to 0.0001 g) into a 100 ml flat-bottomed extraction flask, add 50 ml of deionized water, seal tightly, weigh, shake well, and let stand for 0.5 h. Remove the stopper, connect a reflux condenser, and reflux at 95℃ for 2 h. After cooling to room temperature, remove the flat-bottomed extraction flask, seal tightly again, and weigh. Make up the weight loss with water, shake well, and centrifuge at 3000 rpm for 10 min. Take 25 ml of the supernatant, add 1% α-amylase, and hydrolyze at 50℃ for 10 min. Take the supernatant, centrifuge at 3000 rpm for 10 min, and take 2 ml of the supernatant. Add 3 times the volume of anhydrous ethanol, shake well, and refrigerate at 4℃ for 10 h. Centrifuge at 3000 rpm for 10 min again, discard the supernatant, add 5 ml of deionized water to the precipitate, mix well to dissolve, and then add 1 / 4 volume of a chloroform-n-butanol mixture (chloroform:n-butanol = 4:1). Shake to remove protein. h, the supernatant after protein removal is the test solution for total polysaccharides.

[0075] 4) When testing total nitrogen and total phosphorus:

[0076] Weigh 1 g of soil sample (accurately weighed to 0.0001 g) into a 100 ml Erlenmeyer flask, add 1 ml of pure water to wet the sample, then add 5 ml of 98% concentrated sulfuric acid and 1 ml of hydrogen peroxide in sequence. Cover the mouth of the Erlenmeyer flask with a bent-neck funnel for digestion. Stop digestion when white fumes are emitted. After cooling naturally at room temperature, transfer to a volumetric flask, dilute to 100 ml with pure water, shake well and let stand for 10 min. Measure 25 ml of the supernatant solution into a 100 ml volumetric flask, add 2 ml of 50% sodium hydroxide solution, dilute to 100 ml with pure water and shake well to obtain the test solutions for total nitrogen and total phosphorus.

[0077] 5) When detecting available potassium:

[0078] Weigh 4 g of soil sample (accurately weighed to 0.0001 g) into an extraction bottle, add 20 ml of water and 1 g of ammonium acetate powder, shake well for 15 min and then filter to obtain the test solution of available potassium.

[0079] 6) When detecting ammonium nitrogen:

[0080] Weigh 4 g of soil sample (accurately weighed to 0.0001 g) into an extraction bottle, add 20 ml of water and 1 g of potassium chloride powder, shake well for 15 min and then filter to obtain the test solution of ammonium nitrogen.

[0081] 7) When testing for iron and copper:

[0082] Weigh 5 g of soil sample (accurately weighed to 0.0001 g) into a 50 ml Erlenmeyer flask, add 10 ml of diethylaminetriaminepentaacetic acid extractant, shake for 1 h and filter to obtain iron and copper test solutions. The diethylaminetriaminetriaminepentaacetic acid extractant contains 0.005 mol / L diethylenetriaminepentaacetic acid (DTPA), 0.01 mol / L calcium chloride (CaCl2), and 0.1 mol / L triethanolamine.

[0083] The chemical composition of the test solution of *Trifolium repens* was determined, and the content of essential elements and trace elements in the test solution of the planting soil was determined. The chemical composition included 10 items: extract, total flavonoids, total polysaccharides, catechins, epicatechins, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside (F1), and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside (F2). Essential elements included total nitrogen, total phosphorus, available potassium, and ammonium nitrogen. Trace elements included iron and copper. The content of leachate was determined using reflux extraction for alcohol-soluble leachate. The content of total flavonoids, total polysaccharides, total nitrogen, total phosphorus, available potassium, ammonium nitrogen, iron, and copper was determined using UV-Vis spectrophotometry. The content of catechins, epicatechins, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside, and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside was determined using high-performance liquid chromatography (HPLC). Specifically:

[0084] The content of leachate is detected as follows:

[0085] Measure 25 ml of the test solution of the leachate and place it in an evaporating dish dried to constant weight. Evaporate to dryness in a 100℃ water bath, then dry in an electric hot air drying oven at 105℃ for 3 hours. Cool in a desiccator for 0.5 hours, and weigh the dried product after cooling. Obtain the content of leachate in the test solution of the leachate, expressed as a percentage (%). M J C represents the content of leachate in the test solution. J β is the weight of the dried product. J G is the first dilution factor. J W is the weight of the sample of leachate. J The moisture content of the leachate sample is expressed as a percentage (%). Here, the leachate sample refers to the dried powder used in the pretreatment for leachate detection. Obtaining the moisture content of the sample is a conventional technique for those skilled in the art, such as evaporation and drying using a similar method. In this embodiment, the coefficient is 2, meaning half of the leachate sample solution is used for testing. The average leachate content in all sample solutions under the corresponding planting conditions is taken as the leachate content under the current planting conditions. In this embodiment, there are N=3 planting bags for each planting condition. The average leachate content of the three samples is taken as the leachate content under the current planting conditions, and so on. The first dilution factor is the ratio of the volume of the leachate sample solution obtained in the pretreatment to the volume of the leachate sample solution used for content detection. For example, in this embodiment, the leachate sample solution used for content detection is 25 ml, while the leachate sample solution obtained in the pretreatment is 50 ml, so the first dilution factor is 2 times. The specific dilution factor can be adjusted according to actual needs. Other dilution factors are obtained similarly.

[0086] The total flavonoid content was determined as follows:

[0087] Weigh 10 mg of rutin reference standard, add 8 ml of 70% methanol, and dissolve by sonication. Cool to room temperature, then add 70% methanol to the 10 ml mark of the volumetric flask, and shake well to obtain the rutin reference standard solution. Take 0 ml, 0.1 ml, 0.2 ml, 0.4 ml, 0.7 ml, and 1.0 ml of the rutin reference standard solution respectively, and add water to make up to 1 ml. Place the rutin reference standard solution and 1 ml of total flavonoids test solution into separate volumetric flasks. Add 500 μL of 5% NaNO2 to each volumetric flask, shake well, and let stand for 6 min; add 500 μL of 10% Al(NO3)3, shake well, and let stand for 6 min; add 4 ml of 4% NaOH, shake well, and let stand for 30 min; then add water to make up to the 10 ml mark of the volumetric flask, shake well, and let stand for 15 min to obtain the reagents for the corresponding rutin reference standards. The UV-Vis spectrophotometer was calibrated using a reagent prepared from rutin reference standard (ml). The absorbance was measured using the UV-Vis spectrophotometer to generate a linear regression equation for total flavonoids. The concentration of total flavonoids in the test solution was obtained based on the linear regression equation and multiplied by a second dilution factor to obtain the total flavonoid content in the test solution. The average total flavonoid content in all test solutions under the corresponding planting conditions was taken as the total flavonoid content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer was set to 500 nm.

[0088] The total polysaccharide content was determined as follows:

[0089] Take 0 μL, 25 μL, 50 μL, 100 μL, 200 μL, and 400 μL of glucose standard respectively, and add water to bring the volume to 0.4 ml. Place the glucose standard and 0.4 ml of total polysaccharide test solution into separate glass test tubes. Add 1 ml of 5% phenol solution and 5 ml of 98% concentrated sulfuric acid to each test tube sequentially. Mix well and react in a boiling water bath for 30 min. Allow to cool to room temperature, and then collect 1.5 ml of the supernatant. ml was added to a quartz cuvette, and the absorbance was measured using a UV-Vis spectrophotometer to form a linear regression equation for total polysaccharides. The concentration of total polysaccharides in the test solution was obtained based on the linear regression equation of total polysaccharides, and then multiplied by the third dilution factor to obtain the content of total polysaccharides in the test solution. The average content of total polysaccharides in all test solutions under the corresponding planting conditions was taken as the content of total polysaccharides under the current planting conditions. The wavelength of the UV-Vis spectrophotometer was set to 490 nm.

[0090] The content determination of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside is as follows:

[0091] Weigh the reference standards kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside into volumetric flasks to prepare kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside with a concentration of 25 μg / ml and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside with a concentration of 15 μg / ml. A mixed reference solution of μg / ml was prepared; a reversed-phase ODS column was used, with acetonitrile (flow channel A) and 0.085% phosphoric acid aqueous solution (flow channel B) eluted isocratically at a ratio of 12:88 to elute the mixed reference solution and the test solutions of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside. The detection wavelength was 348 nm, and the flow rate was 1.0 μg / ml. The column flow rate was set at 30℃, and the column temperature was 30℃. Based on the isocratic elution results, the contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside in the corresponding test solutions were calculated. The contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside in all corresponding test solutions under the corresponding planting conditions were also calculated. The mean values ​​of 7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside are respectively the contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside under the current planting conditions. Specifically, the contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside (denoted as F1) and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside (denoted as F2) in the corresponding test solution were calculated based on the isocratic elution results. Specifically, the concentration of F1 in the corresponding test solution was calculated using the concentration and peak area of ​​F1 in the first mixed reference solution, and the peak area of ​​F1 in the corresponding test solution. Similarly, the concentration of F2 in the corresponding test solution was calculated using the concentration and peak area of ​​F2 in the first mixed reference solution, and the peak area of ​​F2 in the corresponding test solution. All of these conditions satisfied the formula... , where C 对照品1 A represents the concentration of F1 or F2 in the first mixed reference solution. 对照品1 C represents the peak area of ​​F1 or F2 in the first mixed reference solution. F To correspond to the concentration of F1 or F2 in the test solution, A F This represents the peak area of ​​F1 or F2 in the corresponding test solution. Then, the content of F1 or F2 in the corresponding test solution is calculated, both satisfying the formula... , of which M F To correspond to the content of F1 or F2 in the test solution, β F G is the fourth dilution factor. F This refers to the weight of the test sample F1 or F2. Here, F1 or F2 refers to the dried powder used in the pretreatment for detecting the content of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside. The effect of different planting conditions on the chemical composition content of *Trifolium repens* can be assessed using the first mixed standard solution, further evaluating the quality of *Trifolium repens*. Specifically, the closer the concentration of F1 or F2 in *Trifolium repens* is to the concentration of F1 or F2 in the first mixed standard solution, the better the quality.

[0092] The content detection of catechins, epicatechins, luteolin, astragaloside, and kaempferol is as follows:

[0093] Weigh 1 mg each of the reference standards catechin, epicatechin, luteolin, astragaloside, and kaempferol, and place them separately in 10 ml (preferably 5 ml-10 ml) volumetric flasks. Add 8 ml of 95% pure methanol and sonicate for 30 min to dissolve. Make up to 10 ml. Prepare a second mixed standard solution with appropriate amounts of each standard, ensuring the final concentrations of catechin, epicatechin, luteolin, astragaloside, and kaempferol are 15.9 μg / ml, 11.3 μg / ml, 7.2 μg / ml, 11.2 μg / ml, and 2.0 μg / ml, respectively. Use a C18 column and gradient elute the second mixed standard solution and the test solutions of catechin, epicatechin, luteolin, astragaloside, and kaempferol. Use acetonitrile (phase A) and 0.085% phosphoric acid (phase B) as the mobile phases, with an acetonitrile elution gradient of 0. min-20 min, 10%-15%; 20 min-40 min, 15%-85%; 40 min-55 min, 35%-100%; detection wavelength 278 nm, flow rate 1.0 ml / min, column temperature 30℃; based on the isocratic elution results, the contents of catechin, epicatechin, luteolin, astragaloside, and kaempferol in the corresponding test solutions were calculated. The average contents of catechin, epicatechin, luteolin, astragaloside, and kaempferol in all corresponding test solutions under the corresponding planting conditions were respectively used as the contents of catechin, epicatechin, luteolin, astragaloside, and kaempferol under the current planting conditions. The contents of catechin, epicatechin, luteolin, astragaloside, and kaempferol in the corresponding test solution were calculated based on the isocratic elution results, as follows: For each component, including catechin, epicatechin, luteolin, astragaloside, and kaempferol, taking catechin as an example, the concentration of catechin in the corresponding test solution was calculated using the concentration and peak area of ​​catechin in the second mixed reference solution and the peak area of ​​catechin in the corresponding test solution, satisfying the formula... , where C 对照品2 A represents the concentration of catechins in the second mixed reference solution. 对照品2 C represents the peak area of ​​catechins in the second mixed reference solution. E To correspond to the concentration of catechins in the test solution, A E This corresponds to the peak area of ​​catechins in the test solution. Then, the content of catechins in the corresponding test solution is calculated, satisfying the formula... , of which M E To correspond to the content of catechins in the test solution, β E G is the fifth dilution factor. EThis represents the weight of the catechin sample, where the catechin sample refers to the dried powder used in the pretreatment for catechin content detection. The calculation of the content of other components in the test solution is similar.

[0094] The detection of total nitrogen and ammonium nitrogen content is as follows:

[0095] Take 1 ml of each of the nitrogen standard solution, the total nitrogen test solution, and the ammonium nitrogen test solution, add 100 μl of mixing accelerator and shake well, then add 100 μl of indicator, shake well, let stand for 30 min, and then add water to make up to 5 ml. Measure the absorbance using a UV-Vis spectrophotometer. Calculate the concentration of the total nitrogen test solution based on the absorbance of the total nitrogen test solution, the absorbance of the nitrogen standard solution, and the concentration of the nitrogen standard solution; this is the total nitrogen content in the total nitrogen test solution. Similarly, calculate the concentration of the ammonium nitrogen test solution based on the absorbance of the ammonium nitrogen test solution, the absorbance of the nitrogen standard solution, and the concentration of the nitrogen standard solution; this is the ammonium nitrogen content in the ammonium nitrogen test solution. The calculation formulas are as follows: , where C ns A represents the concentration of the test solution containing total nitrogen or ammonium nitrogen. ns C represents the absorbance of the test solution containing total nitrogen or ammonium nitrogen. sn A represents the concentration of the nitrogen standard solution. sn The absorbance of the nitrogen standard solution is used to represent the total nitrogen content in the test solution under the corresponding planting conditions and the average ammonium nitrogen content in the test solution under the corresponding planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 430 nm. The mixing accelerator is potassium sulfate:copper sulfate:selenium = 100:10:1 dissolved in 10 times the volume of water. The indicator is methyl red:bromocresol green = 1:5 dissolved in 10 times the volume of ethanol.

[0096] The total phosphorus content was determined as follows:

[0097] Take 1 ml of the corresponding phosphorus standard solution and the total phosphorus test solution, add 100 μl of colorimetric reagent and shake well. Then add 100 μl of 0.5% potassium antimony tartrate solution, shake well, let stand for 10 min, and add water to make up to 5 ml. Measure the absorbance using a UV-Vis spectrophotometer. Calculate the concentration of the total phosphorus test solution based on the absorbance of the total phosphorus test solution, the absorbance of the phosphorus standard solution, and the concentration of the phosphorus standard solution. This concentration is the total phosphorus content in the total phosphorus test solution. The average total phosphorus content in all total phosphorus test solutions under the corresponding planting conditions is taken as the total phosphorus content under the current planting conditions, as shown in the calculation formula. , where C ps A represents the concentration of total phosphorus in the test solution. ps The absorbance of the test solution representing total phosphorus, C sp Indicates the concentration of the phosphorus standard solution, Asp The absorbance of the phosphorus standard solution is indicated by the wavelength of the UV-Vis spectrophotometer set to 700 nm. The colorimetric reagent is 10 g of ammonium molybdate dissolved in 1 L of water, and then 126 ml of 98% concentrated sulfuric acid is added.

[0098] The detection of available potassium content is as follows:

[0099] Take 1 ml of potassium standard solution and 1 ml of available potassium test solution, add 100 μl of 0.5 M sodium sulfate solution and shake well. Then add 100 μl of sodium tetraphenylborate solution, shake well, let stand for 10 min, and add water to make up to 5 ml. Measure the absorbance using a UV-Vis spectrophotometer. Calculate the concentration of available potassium in the test solution based on the absorbance of the available potassium test solution, the absorbance of the potassium standard solution, and the concentration of the potassium standard solution. This concentration is the available potassium content in the test solution, as shown in the calculation formula. , where C ks A represents the concentration of available potassium in the test solution. ks C represents the absorbance of the test solution containing available potassium. sk Indicates the concentration of potassium standard solution, A sk The absorbance of the potassium standard solution is indicated, and the average content of available potassium in the test solution under the corresponding planting conditions is taken as the content of available potassium under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 420 nm.

[0100] The iron content testing is as follows:

[0101] Take 100 μl of both the iron standard solution and the iron test solution, and add 100 μl of hydroxylamine hydrochloride solution, 200 μl of o-phenanthroline, and 500 μl of acetate-sodium acetate buffer solution sequentially for color development. After shaking and standing for 20 min, measure the absorbance using a UV-Vis spectrophotometer. Calculate the concentration of the iron test solution based on the absorbance of the iron test solution, the absorbance of the iron standard solution, and the concentration of the iron standard solution. This concentration is the iron content in the iron test solution, as shown in the calculation formula. , where C Fes A represents the concentration of iron in the test solution. Fes C represents the absorbance of the test solution containing iron. sFe Indicates the concentration of the iron standard solution, A sFe The absorbance of the iron standard solution is indicated, and the average iron content in all iron test solutions under the corresponding planting conditions is taken as the iron content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 510 nm.

[0102] The copper content testing is as follows:

[0103] Take 100 μl of copper standard solution and copper test solution respectively, and add 500 μl of 0.5 mol / L ammonium citrate solution, 500 μl of 0.1 mol / L disodium EDTA solution and 200 μl of carbon tetrachloride in sequence. Shake well, then add 0.05 g of sodium diethyldithiocarbamate, shake well and let stand for 20 min. Measure the absorbance using a UV-Vis spectrophotometer. Calculate the concentration of copper in the test solution based on the absorbance of the copper test solution, the absorbance of the copper standard solution, and the concentration of the copper standard solution. This concentration is the copper content in the copper test solution, as shown in the calculation formula. , where C Cus A represents the concentration of copper in the test solution. Cus C represents the absorbance of the test solution containing copper. sCu Indicates the concentration of the copper standard solution, A sCu The absorbance of the copper standard solution is indicated, and the average copper content in all copper test solutions under the corresponding planting conditions is taken as the copper content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 510 nm.

[0104] The standard curves are generated by plotting absorbance as the ordinate and the concentration of the corresponding term as the abscissa for each linear regression equation, satisfying the following conditions: Where x is absorbance, a and b are constants, and y is the concentration of the corresponding term. The linear regression equation for total flavonoids is: y = 0.9952x + 0.0018 (R² + φ²) 2 = 0.9994); Linear regression equation for total polysaccharides: y = 0.376x - 0.0059 (R² = 0.9994) 2 = 0.9990), R 2 It is expressed as the sum of squares of the differences between the sample points and the mean line. While detecting the content of total nitrogen, total phosphorus, available potassium, ammonium nitrogen, iron, and copper, blank tests were also performed using pure water as a blank to calibrate the UV-Vis spectrophotometer.

[0105] The weights of each item were determined using the entropy weight (EW) method based on the content of chemical components under the corresponding planting conditions. The entropy weight method was used to analyze the weights of each indicator: First, seven wood ash treatment groups were selected, and the average content of the main soil components and the average content of chemical components of *Trifolium repens* in the corresponding wood ash treatment groups were measured. The data were standardized using SPSS Pro software (positive index processing). The weights of each indicator (including extractives, total flavonoids, total polysaccharides, catechins, epicatechins, osmanthus glycosides, astragaloside, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside, and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside) were analyzed using the entropy weight method. Seven compounds (catechin, epicatechin, luteolin, astragaloside, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside, kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside) as well as alcohol-soluble extracts, total flavonoids and total polysaccharides were included in the study. The compound with the highest weight was kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside (F2) (15.72%), followed by catechin (12.953%) and kaempferol (12.555%), while the compound with the lowest weight was total flavonoids (5.717%).

[0106] The quality of *Trifolium repens* was evaluated using the Top-to-Bottom Solution Distance Method (TOPSIS) based on the weights of various factors under corresponding planting conditions. TOPSIS was used to evaluate the relationship between the medicinal quality of *Trifolium repens* cultivated in different wood ash treatment groups and the main components of the soil. The content of alcohol-soluble extract, seven compounds, total flavonoids, total polysaccharides, and the yield of *Trifolium repens* were all included as positive indicators in the TOPSIS evaluation. The optimal and worst matrix vectors were determined using the entropy weight method. The positive ideal solution distance D+ and negative ideal solution distance D- were calculated for each evaluated object. The comprehensive score index S was calculated based on the positive and negative ideal solution distances D+ and D-. The comprehensive score indices S of each wood ash treatment group were ranked; a higher S value indicates better medicinal quality of *Trifolium repens*. The results showed that group B ranked first, followed by group D. The evaluation method combining the distance between superior and inferior solutions and the weighting is a well-known technique in the field and will not be elaborated here. For example, see the reference: Jiang Yani, Zhang Zhenhong, Kadirey Tursunmaiti, Wu Lingzi, Ye Wanting, Wang Yanmin, Xu Yanrui, Fan Youmin, Ma Jiabao, Tao Ou, Wang Jingjuan. Enrichment pattern of inorganic elements, health risk assessment and quality evaluation method of Astragalus membranaceus based on AHP-CRITIC weighted TOPSIS model combined with chemometrics [J]. Chinese Journal of Inorganic Analytical Chemistry, 1-21.

[0107] The correlation between the quality of *Trifolium repens* and soil components was analyzed using the grey relational analysis method. Grey relational analysis calculates the correlation between the comparison sequence and the parent sequence. In this example, yield, kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside (F2), catechins, and kaempferol content were used as parent sequences, and the content of each element in the planting soil was used as the comparison sequence for grey relational analysis. A correlation score > 0.9 was considered a high correlation. The results showed that the yield and kaempferol content of *Trifolium repens* were highly correlated with ammonium nitrogen, copper, and iron; the contents of kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside (F2) and catechins were highly correlated with the content of available potassium.

[0108] This method employed entropy weighting to perform weighted analysis on the chemical components of *Tripterygium wilfordii*. Subsequently, using the content of essential elements, trace elements, and chemical components as positive indicators, the TOPSIS method was used to evaluate the quality of *Tripterygium wilfordii* from different wood ash treatment groups. The results showed that the evaluation ranking for different wood ash treatment groups was B>D>A>G>F>E>C. Furthermore, the top three chemical components with higher weights in the entropy weighting analysis, along with the yield of *Tripterygium wilfordii*, were used as parent sequences to analyze the influence of the abundance of common elements in the planting soil on important indicators affecting the quality evaluation of the medicinal material. The results showed that the yield of cultivated *Tripterygium wilfordii* was highly correlated with the contents of total nitrogen, copper, and iron in the planting soil, at 0.996, 0.995, and 0.995, respectively. The content of kaempferol in *Tripterygium wilfordii* was also highly correlated with the contents of total nitrogen, copper, and iron, at 0.994, 0.993, and 0.992, respectively. The contents of catechin and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside (F2) were highly correlated with available potassium, at 0.929 and 0.962, respectively. Therefore, the contents of total nitrogen, copper, and iron in the planting soil have a significant impact on the yield and kaempferol content of cultivated *Tripterygium wilfordii*, while the contents of available potassium in the planting soil have a significant impact on the contents of catechin and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside (F2). In summary, among the seven wood ash treatment groups, group B showed the best overall quality of cultivated *Trifolium repens*. This method provides technical guidance for the cultivation of *Trifolium repens* and is beneficial for improving the quality of the medicinal material.

[0109] Table 1 Evaluation results of the Top-Inferior Solution Distance Method (TOPSIS)

[0110]

[0111] Table 2 Evaluation Results of Grey Relational Analysis

[0112]

[0113] Combining the above parameters and Figure 2 , Figure 3 and Figure 4 It can be seen that, Figure 2 In the study, the mixed reference standard F1 and F2 was the first mixed reference standard solution, and the wood ash treatment group A was the group A (other wood ash treatment groups were not shown). The results showed that the retention time of F1 in group A was 8.860 min, and the retention time of F2 was 16.765 min, which had the best quality. Figure 3 A, B, C, D, E, F, and G correspond to groups A, B, C, D, E, F, and G, respectively. These represent the content detection results of various chemical components in *Trifolium repens* from seven wood ash treatment groups. The results show that compared with the control group (group A), A p-value < 0.05 indicates that the difference is statistically significant. ns indicates that P < 0.01, meaning the difference is significant; ns indicates that P > 0.05, meaning the difference is not significant; P is the P-value, representing the probability value. Figure 4 The contents of various components in the planting soil of the seven wood ash treatment groups were determined. The results showed that compared with the control group (Group A), the total nitrogen and ammonium nitrogen contents of Group B were significantly increased, the total phosphorus contents of Groups C, E and F were significantly increased, the ammonium nitrogen contents of Groups C and D were also significantly increased, the ammonium nitrogen contents of Group F were significantly decreased, and there were no significant differences in the contents of the other components compared with the control group (Group A).

[0114] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The embodiments described above are merely specific and detailed examples of the embodiments described in this application, and should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A method for detecting the correlation between the quality of *Trifolium repens* and soil composition, characterized in that: Includes the following steps: S1. Pretreatment was performed on *Trifolium repens* and the planting soil under different planting conditions to obtain corresponding test solutions. The different planting conditions included seven wood ash treatment groups, which were designated as Group A, Group B, Group C, Group D, Group E, Group F, and Group G. Group A had 0 kg of wood ash added and served as the control group. Group B had 1 kg of wood ash added as base fertilizer. Group C had 2 kg of wood ash added as base fertilizer. Group D had 1 kg of wood ash added as top dressing. Group E had 2 kg of wood ash added as top dressing. Group F had 0.5 kg of wood ash added as base fertilizer and 0.5 kg of top dressing. Group G had 1 kg of wood ash added as base fertilizer and 1 kg of top dressing. S2. The chemical composition of the test solution of *Trifolium repens* was tested, and the content of essential elements and trace elements in the test solution of the planting soil was tested. The chemical components include extracts, total flavonoids, total polysaccharides, catechins, epicatechins, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside; The content detection of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside is as follows: Weigh the reference standards kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside into volumetric flasks to prepare concentrations of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside at 10 μg / ml-30 μg / ml and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside at 5 μg / ml-20 μg / ml. A first mixed reference solution of μg / ml was used; a reversed-phase ODS column was employed, with isocratic elution of the first mixed reference solution and the test solutions of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside. Mobile phase A: acetonitrile; mobile phase B: 0.085% phosphoric acid aqueous solution, with acetonitrile:0.085% phosphoric acid aqueous solution = 12:88; detection wavelength: 348 nm; flow rate: 1.0 μg / ml. The column flow rate was set at 25℃-35℃. Based on the isocratic elution results, the contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside in the corresponding test solutions were calculated. The contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside in all corresponding test solutions under the corresponding planting conditions were also calculated. The mean values ​​of 3-O-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside are respectively used as the contents of kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside under the current planting conditions; S3. Determine the weight of each item based on the content of chemical components under the corresponding planting conditions using the entropy weight method. S4. Evaluate the quality of *Trifolium repens* using the superior-inferior solution distance method based on the weights of each item under the corresponding planting conditions. S5. Using the yield of *Trifolium repens* under the best planting conditions and the content of the top K items with the highest weight in chemical composition as the mother sequence, and the content of essential elements and trace elements in the corresponding planting soil as the comparison sequence, the grey relational analysis method is used to determine the correlation between the quality of *Trifolium repens* and soil composition. When the correlation exceeds the preset threshold, it is considered that the quality of *Trifolium repens* is highly correlated with the corresponding elements in the soil composition.

2. The method for detecting the correlation between the quality of *Trifolium repens* and soil composition as described in claim 1, characterized in that: The essential elements include total nitrogen, total phosphorus, available potassium, and ammonium nitrogen, and the trace elements include iron and copper.

3. The method for detecting the correlation between the quality of *Trifolium repens* and soil composition as described in claim 2, characterized in that: The content of the leachate was determined by reflux extraction. The content of total flavonoids, total polysaccharides, total nitrogen, total phosphorus, available potassium, ammonium nitrogen, iron, and copper was determined by ultraviolet-visible spectrophotometry. The content of catechins, epicatechins, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside was determined by high performance liquid chromatography.

4. The method for detecting the correlation between the quality of *Trifolium repens* and soil composition as described in claim 3, characterized in that: The content detection of the leachate is as follows: Take 10-30 ml of the test solution of the leachate and place it in an evaporating dish dried to constant weight. Evaporate to dryness in a water bath at 90℃-100℃, then dry in an electric hot air drying oven at 100℃-110℃ for 3 hours. Cool in a desiccator for 0.5-1.0 h, and weigh the dried product after cooling. Obtain the content of leachate in the test solution of the leachate, expressed as a percentage (%). M J C represents the content of leachate in the test solution. J β is the weight of the dried product. J G is the first dilution factor. J W is the weight of the sample of leachate. J The moisture content of the test sample of the leachate is expressed as %, and the average content of the leachate in the test solution of all leachates under the corresponding planting conditions is taken as the content of the leachate under the current planting conditions. The determination of the total flavonoid content is as follows: Weigh 5-15 mg of rutin reference standard, add 5-8 ml of 70%-100% methanol, dissolve by sonication, cool to room temperature, and then add 70%-100% methanol to the 10 ml mark of the volumetric flask. Shake well to obtain the rutin reference standard solution. Measure 0 ml, 0.1 ml, 0.2 ml, 0.4 ml, 0.7 ml, and 1.0 ml of the rutin reference standard solution, respectively, and add water to make up to 1 ml. Place the rutin reference standard solution and 0.5 ml-2 ml of the total flavonoid test solution into separate volumetric flasks. Add 200 μL-500 μL of 5% NaNO2 to each volumetric flask, shake well, and let stand for 5-10 min; add 200 μL-500 μL of 10% Al(NO3)3, shake well, and let stand for 5-10 min; add 2 ml-5 ml of 4% NaOH, shake well, and let stand for 20-40 min. Add water to the volumetric flask to the 10ml mark, shake well and let stand for 10-20 minutes to obtain the reagent for the corresponding rutin reference solution. Use a UV-Vis spectrophotometer to detect the absorbance. Based on the absorbance and concentration of different rutin reference solutions, form a linear regression equation for total flavonoids. Then, substitute the absorbance of the test solution of total flavonoids into the linear regression equation of total flavonoids to calculate the concentration of total flavonoids in the test solution. Multiply by the second dilution factor to obtain the content of total flavonoids in the test solution. The average content of total flavonoids in all test solutions of total flavonoids under the corresponding planting conditions is taken as the content of total flavonoids under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 490nm-520nm. The detection of the total polysaccharide content is as follows: Take 0 μL, 25 μL, 50 μL, 100 μL, 200 μL, and 400 μL of glucose reference standard, respectively, and add water to bring the volume to 0.4 ml–1 ml. Place the glucose reference standard and 0.4 ml–1 ml of total polysaccharide test solution into separate glass test tubes. Add 1 ml–2 ml of 5% phenol solution and 3 ml–7 ml of 90%–98% concentrated sulfuric acid to each test tube sequentially. Mix well and react in a boiling water bath for 30–60 minutes. Allow to cool to room temperature, and then take 1.5 ml–2 ml of the supernatant. ml was added to a quartz cuvette, and the absorbance was measured using a UV-Vis spectrophotometer. A linear regression equation for total polysaccharides was formed based on the absorbance and concentration of different glucose standards. The absorbance of the test solution of total polysaccharides was then substituted into the linear regression equation to calculate the concentration of total polysaccharides in the test solution. This concentration was then multiplied by the third dilution factor to obtain the total polysaccharide content in the test solution. The average total polysaccharide content in all test solutions of total polysaccharides under the corresponding planting conditions was taken as the total polysaccharide content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer was set to 490 nm-520 nm. The detection of total nitrogen and ammonium nitrogen content is as follows: Take 0.5 ml to 1 ml of each of the nitrogen standard solution, the total nitrogen test solution, and the ammonium nitrogen test solution, add 50 μl to 100 μl of mixed accelerator and shake well, then add 50 μl to 100 μl of indicator, shake well, let stand for 15 min to 60 min, and then add water to bring the volume to 2 ml to 5 ml. The absorbance was measured using a UV-Vis spectrophotometer. The concentration of the total nitrogen in the test solution was calculated based on the absorbance of the total nitrogen test solution, the absorbance of the nitrogen standard solution, and the concentration of the nitrogen standard solution. Similarly, the concentration of the ammonium nitrogen in the test solution was calculated based on the absorbance of the ammonium nitrogen test solution, the absorbance of the nitrogen standard solution, and the concentration of the nitrogen standard solution. The average total nitrogen content in all total nitrogen test solutions and the average ammonium nitrogen content in all ammonium nitrogen test solutions under the corresponding planting conditions were then used as the total nitrogen content and ammonium nitrogen content under the current planting conditions, respectively. The wavelength of the UV-Vis spectrophotometer was set to 410 nm. nm-430nm, the mixed accelerator is potassium sulfate:copper sulfate:selenium = 100:10:1 dissolved in 10 times the volume of water; the indicator is methyl red:bromocresol green = 1:5 dissolved in 10 times the volume of ethanol; The determination of total phosphorus content is as follows: Take 0.5 ml-1 ml of phosphorus standard solution and total phosphorus test solution respectively, add 50 μl-100 μl of colorimetric reagent and shake well, then add 50 μl-100 μl of 0.5% potassium antimony tartrate solution, shake well and let stand for 5 min-10 min, then add water to make up to 2 ml-5 ml, and use a UV-Vis spectrophotometer to detect the absorbance. Calculate the concentration of the total phosphorus test solution based on the absorbance of the total phosphorus test solution, the absorbance of the phosphorus standard solution and the concentration of the phosphorus standard solution. The average total phosphorus content in all total phosphorus test solutions under the corresponding planting conditions is taken as the total phosphorus content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 700 nm. The colorimetric reagent is 10 g ammonium molybdate dissolved in 1 L of water and then 126 ml of 90%-98% concentrated sulfuric acid. The detection of the effective potassium content is as follows: Take 0.5 ml-1 ml of potassium standard solution and available potassium test solution respectively, add 50 μl-100 μl of 0.5 M sodium sulfate solution and shake well, then add 50 μl-100 μl of sodium tetraphenylborate solution, shake well and let stand for 5 min-10 min, then add water to make up to 2 ml-5 ml, and use a UV-Vis spectrophotometer to detect the absorbance. Calculate the concentration of available potassium in the test solution based on the absorbance of the available potassium test solution, the absorbance of the potassium standard solution, and the concentration of the potassium standard solution. The average effective potassium content in all available potassium test solutions under the corresponding planting conditions is taken as the effective potassium content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 420 nm. The iron content detection is specifically as follows: Take 50 μl-100 μl of iron standard solution and iron test solution respectively, and add 50 μl-100 μl of hydroxylamine hydrochloride solution, 50 μl-200 μl of o-phenanthroline and 100 μl-500 μl of acetate-sodium acetate buffer solution in sequence for color development. After shaking and standing for 10 min-30 min, use a UV-Vis spectrophotometer to detect the absorbance. Calculate the concentration of the iron test solution based on the absorbance of the iron test solution, the absorbance of the iron standard solution, and the concentration of the iron standard solution. The average iron content in all iron test solutions under the corresponding planting conditions is taken as the iron content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 510 nm. The copper content detection is performed as follows: Take 50 μl-100 μl of copper standard solution and copper test solution respectively, and add 500 μl of ammonium citrate solution (0.1 mol / L-0.5 mol / L), 100 μl-500 μl of disodium EDTA solution (0.05 mol / L-0.1 mol / L), and 50 μl-200 μl of carbon tetrachloride, respectively. Shake well, then add 0.02 g-0.05 g of sodium diethyldithiocarbamate, shake well, and let stand for 10 min-30 min. Measure the absorbance using a UV-Vis spectrophotometer. Calculate the concentration of the copper test solution based on the absorbance of the copper test solution, the absorbance of the copper standard solution, and the concentration of the copper standard solution. This concentration is the copper content in the copper test solution. The average copper content in all copper test solutions under the corresponding planting conditions is taken as the copper content under the current planting conditions. The wavelength of the UV-Vis spectrophotometer is set to 510 nm.

5. The method for detecting the correlation between the quality of *Trifolium repens* and soil composition as described in claim 4, characterized in that: Each of the aforementioned linear regression equations is used to plot a standard curve with absorbance as the ordinate and the concentration of the corresponding term as the abscissa, which satisfies the following conditions. Where x is absorbance, a and b are constants, and y is the concentration of the corresponding term.

6. The method for detecting the correlation between the quality of *Trifolium repens* and soil composition as described in claim 2, characterized in that: Before the soil pretreatment, the following steps are performed: In each experimental area, N planting bags of *Trifolium repens* were randomly selected for harvesting. During harvesting, the following operations were performed on each planting bag: a ring cut was made 10 cm above the ground, and M sampling points were set at the ring cut with a diameter of 5 cm from the center of the planting bag. After removing crop roots, insects, and stones from the soil at each sampling point, the soil was air-dried and crushed, and then passed through a 1 mm to 2 mm sieve to obtain soil samples. The samples were then packaged, preserved, and labeled. Before the pretreatment of *Trifolium repens*, the following operations are also performed: Pick the tuberous roots of *Trifolium repens* from the corresponding planting bags, wash and dry them, cut them into 2mm-4mm thick slices, dry them at 55℃, weigh them, and then crush them through a 50-mesh sieve. Mix the coarse powder that cannot pass through the 50-mesh sieve with the fine powder that has passed through the 50-mesh sieve. The proportion of fine powder in the mixed coarse powder and fine powder should exceed 90%, and this mixture is recorded as dry powder.

7. The method for detecting the correlation between the quality of *Trifolium repens* and soil composition as described in claim 6, characterized in that: The preprocessing is as follows: 1) When testing leachate: Weigh 2-4 g of the dried powder into a flat-bottomed extraction bottle, add 50-100 ml of 70% ethanol, seal tightly and weigh, let stand for 1 hour, remove the stopper and connect a reflux condenser, heat to boiling and maintain for 1 hour, cool to room temperature, remove the flat-bottomed extraction bottle, seal tightly and weigh again, replenish the lost weight with water, shake well and filter through a dry filter to obtain the test solution of the extract; 2) When detecting total flavonoids, catechins, epicatechins, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apigenin-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside: Weigh 1-2 g of the dried powder into a flat-bottomed extraction flask, add 25-50 times the volume of methanol with a concentration of 60%-90%, and weigh again. Reflux at 80℃-95℃ for 1-2 h. After cooling to room temperature, add methanol to the corresponding concentration, filter to obtain the initial test solution, which is the test solution for total flavonoids. Then, measure 20-40 ml of the filtrate of the initial test solution into an evaporating dish and concentrate it to 10-25 ml in a water bath at 80℃-100℃ to obtain the test solutions for catechin, epicatechin, luteolin, astragalin, kaempferol, kaempferol-3-O-β-D-apicoside-(1→2)-β-D-glucoside-7-O-α-L-rhamnoside and kaempferol-3-O-β-D-glucoside-7-O-α-L-rhamnoside. 3) When detecting total polysaccharides: Weigh 1-2 g of the dried powder into a flat-bottomed extraction flask, add 50-100 ml of deionized water, seal tightly, weigh, shake well, and let stand for 0.5-1.0 h. Remove the stopper and connect a reflux condenser. Reflux at 90-100℃ for 1.5-3.0 h. After cooling to room temperature, remove the flat-bottomed extraction flask, seal tightly again, and weigh. Replenish the lost weight with water, shake well, and centrifuge at 3000-4500 rpm for 5-15 min. Take 25-50 ml of the supernatant, add 1%-5% α-amylase, and hydrolyze by shaking at 35-50℃ for 10-30 min. Remove the supernatant, centrifuge at 3000-4500 rpm for 5-15 min, and take 2-10 ml of the supernatant. Add 3-5 times the amount of anhydrous ethanol, shake well, and refrigerate at 0-4℃ for at least 10 hours. Then centrifuge at 3000-4500 rpm for 10-15 min. Centrifuge at 4500 rpm for 5 min-15 min, discard the supernatant, add 5 ml-25 ml of deionized water and mix well to dissolve, then add 1 / 3 to 1 / 5 volume of chloroform-n-butanol mixed solution with chloroform:n-butanol = 4:1 and shake to remove protein for 1 h-2 h. The supernatant after protein removal is the test solution for total polysaccharides. 4) When testing total nitrogen and total phosphorus: Weigh 1-2 g of soil sample into an Erlenmeyer flask, add 0.5-2 ml of pure water to wet the sample, then add 4-8 ml of 90%-98% concentrated sulfuric acid and 0.5-2 ml of hydrogen peroxide. Cover the mouth of the Erlenmeyer flask with a bent-neck funnel for digestion until white fumes are emitted. After cooling to room temperature, transfer the solution to a volumetric flask, dilute to 100 ml with pure water, shake well, and let stand for 10-20 minutes. Measure 20-45 ml of the supernatant and place it in a volumetric flask, add 2-5 ml of 50% sodium hydroxide solution, dilute to 100 ml with pure water, and shake well to obtain the test solutions for total nitrogen and total phosphorus. 5) When detecting available potassium: Weigh 4-8 g of soil sample into an extraction bottle, add 20-40 ml of water and 1-2 g of ammonium acetate powder, shake well for 10-20 min and then filter to obtain the test solution for available potassium. 6) When detecting ammonium nitrogen: Weigh 4-8 g of soil sample into an extraction bottle, add 20-40 ml of water and 1-2 g of potassium chloride powder, shake well for 10-20 min and then filter to obtain the test solution for ammonium nitrogen. 7) When testing for iron and copper: Weigh 5-10 g of soil sample into an Erlenmeyer flask, add 10-20 ml of diethylaminetributyric acid ethylenediaminepentaacetic acid extractant, shake for 0.5-2.0 h, and then filter to obtain the test solutions for iron and copper. The diethylaminetributyric acid ethylenediaminepentaacetic acid extractant contains 0.005 mol / L of diethylenetriaminepentaacetic acid, 0.01 mol / L of calcium chloride, and 0.1 mol / L of triethanolamine.

8. The method for detecting the correlation between the quality of *Trifolium repens* and soil composition as described in claim 1, characterized in that: The quality of *Trifolium repens* is evaluated using the superior-inferior solution distance method based on the weights of each item under the corresponding planting conditions. This method uses the yield of *Trifolium repens* under the corresponding planting conditions and the content of each item in the chemical composition as positive indicators. The optimal and inferior matrix vectors are obtained based on the weights of each item in the chemical composition. Then, the comprehensive score index S is calculated based on the positive ideal solution distance D+ and the negative ideal solution distance D- under the corresponding planting conditions, and the samples are ranked. The higher the comprehensive score index S, the better the quality of *Trifolium repens* under the corresponding planting conditions.

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