Soil geochemical non-component data generation method based on mass concentration and volume density conversion

Abstract

The invention discloses a soil geochemical non-component data generation method based on mass concentration and volume density conversion, and belongs to the technical field of soil geochemical non-component data generation method.The method comprises the steps that a, a soil sample is obtained, b, the mass concentration of target elements in the soil sample is measured, the target elements comprise major elements and microelements, and c, the mass concentration of the major elements is measured; the mass concentration of the main elements is expressed by mass fraction, and the mass concentration of the trace elements is expressed by milligram per kilogram, c, measuring the volume density of the soil sample with the unit of gram per cubic centimeter, and d, calculating the soil chemical density of the target elements according to the mass concentration obtained in the step b and the volume density obtained in the step c through a formula VC = a * MC * BD, vC is the chemical density of the soil, the unit is milligram per cubic centimeter, a is the unit conversion coefficient, and e, taking the chemical density of the soil as the geochemical non-component data of the soil.

Description

Technical Field

[0001] This invention relates to a method for generating soil geochemical non-component data, and particularly to a method for generating soil geochemical non-component data based on the conversion between mass concentration and volume density, belonging to the technical field of soil geochemical non-component data generation methods. Background Technology

[0002] Soil geochemical data are a crucial foundation for soil science, agricultural, and environmental research. Traditionally, soil chemical composition is expressed as mass concentration, such as major elements as percentages and microelements as milligrams per kilogram.

[0003] This form of expression belongs to component data, which has the characteristics of relativity and summation constraints. This can lead to spurious correlations in data analysis, limiting its application in statistical analysis and spatial distribution research.

[0004] Existing technologies attempt to process compositional data through mathematical transformations (such as central logarithmic transformations), but have failed to completely solve the relativity problem and have not explored a volume-based method for representing non-compositional data. To address these issues, a method for generating soil geochemical non-compositional data based on the conversion between mass concentration and volume density is designed. Summary of the Invention

[0005] The main objective of this invention is to provide a method for generating soil geochemical non-component data based on the conversion between mass concentration and volume density.

[0006] The objective of this invention can be achieved by adopting the following technical solution: A method for generating non-component soil geochemical data based on the conversion of mass concentration to volume density includes the following steps: a. Obtain soil samples; b. Determine the mass concentration of the target element in the soil sample, wherein the target element includes major elements and trace elements, the mass concentration of major elements is expressed as a mass fraction, and the mass concentration of trace elements is expressed as milligrams per kilogram; c. Determine the bulk density of the soil sample, in grams per cubic centimeter; d. Based on the mass concentration obtained in step b and the volume density obtained in step c, calculate the soil chemical density of the target element using the formula VC=a×MC×BD; Where VC is the soil chemical density, measured in milligrams per cubic centimeter, and a is the unit conversion factor; e. Use the soil chemical density as soil geochemical non-component data.

[0007] Preferably, in step b, the mass concentration of the major element is determined by X-ray fluorescence spectroscopy, specifically including: Sample preparation: After drying the soil sample, grind it to a particle size of less than 0.075 mm, and take a portion of the sample to press it into a disc with a diameter of 32 mm; Instrument testing: The disc was tested using an energy-dispersive XRF spectrometer, which excited X-rays and recorded the fluorescence spectrum; The instrument was calibrated using standard soil samples to generate a calibration curve. The result is calculated using the formula. Calculate the mass concentration; in I represents the mass concentration of the main element, I represents the fluorescence intensity, and k and b represent the slope and intercept of the calibration curve, respectively.

[0008] Based on the previous testing process for replenishing soil organic matter.

[0009] Preferably, in step b, the mass concentration of trace elements is determined by inductively coupled plasma mass spectrometry, specifically including: sample pretreatment: taking 0.5g of the ground soil sample, adding... Add 2 mL of HF to a sealed container and microwave digest at 180 °C for 30 min. Dilute the digestion solution to 50 mL and add an internal standard. Inductively coupled plasma mass spectrometry was used to detect elemental ion signals in the digestion solution. Calibrate using multi-element standard solutions, with a calibration concentration range of 0.1-100 μg / L; Result calculation: using formula MC icp-ms The mass concentration is calculated as Cs·V·D / m, where MC icp-ms denoted as Cs, where Cs is the concentration of trace elements, V is the final solution volume, m is the sample mass, and D is the dilution factor.

[0010] Preferably, in step c, the soil bulk density (BD) is determined by the ring sampler method, specifically including: Sample collection was performed by vertically pressing a 100cm³ ring cutter into undisturbed soil to collect undisturbed soil samples and removing excess soil outside the ring cutter. The soil-containing ring cutter was placed in an oven at 105℃ and dried to constant weight. After cooling, the total mass of the ring cutter and dry soil, as well as the mass of the ring cutter, were weighed. The result was calculated using the formula BD=( ) ÷ V to calculate the bulk density, where The total mass of the cutter head and dry soil is [not specified]. V represents the mass of the ring cutter, and V represents the volume of the ring cutter.

[0011] Preferably, the ring cutter method is suitable for naturally occurring soils with a bulk density of 0.8-2.0 g / cm³.

[0012] Preferably, in step d, the unit conversion factor a is: when MC is the mass concentration of the main element, a = 10; When MC is the mass concentration of trace elements .

[0013] Preferably, when the principal element is Furthermore, when its mass concentration is 60% and the soil volume density is 1.5 g / cm³, the corresponding soil chemical density VC = 10 × 60% × 1.5 = 90 mg / cm³.

[0014] Preferably, when the trace element is Zn with a mass concentration of 50 mg / kg and the soil bulk density is 1.5 g / cm³, the corresponding soil chemical density is... .

[0015] Preferably, in step e, the non-component data is used to break the summation constraint of traditional component data and avoid spurious correlations in data analysis.

[0016] Preferably, the non-component data can be used for soil carbon storage assessment or total pollution calculation of contaminated sites: When assessing carbon storage, the carbon storage per unit area is calculated by combining the soil chemical density of organic carbon with soil volume. When calculating the total amount of pollution, the total amount of pollution is calculated by combining the soil chemical density of pollutants with the area and depth of the contaminated site.

[0017] Beneficial technical effects of the present invention: The present invention provides a method for generating non-component soil geochemical data based on the conversion of mass concentration and volume density. Traditional soil geochemical data is expressed in terms of mass concentration, which is component data. It is constrained by the sum of 100%, which makes the data relative and prone to producing spurious correlations in statistical analysis, interfering with the accuracy of research conclusions.

[0018] This invention calculates soil chemical density by combining mass concentration and volumetric density, freeing the data from the constraint of summation and making it absolutely non-component data. For example, when the mass concentration of SiO2 in the soil is 60% and Al2O3 is 20%, traditional data is limited by the remaining 20% ​​being filled by other components; however, after conversion to VC, the values ​​of the two are calculated independently, avoiding interference from the correlation of component data, and providing a more reliable basis for subsequent statistical analysis and spatial distribution studies.

[0019] This invention innovates data representation methods and broadens application scenarios. For the first time, it proposes to use soil chemical density (VC, mg / cm³) as the core indicator of non-component data, transforming the traditional element content per unit mass into the absolute element content per unit volume, which is more in line with the physical-chemical characteristics of soil in its natural state.

[0020] In agricultural research, VC can directly reflect the actual storage of nutrients (such as nitrogen, phosphorus, and potassium) per unit volume of soil, providing a quantitative basis for precision fertilization; In environmental assessment, VC can be used to quickly calculate the total amount of pollution at a contaminated site, solving the problem that traditional mass concentrations are difficult to use directly for total amount estimation. In soil carbon cycle research, the VC value of organic carbon can be directly correlated with the carbon storage per unit area of ​​soil, providing a more intuitive parameter for carbon sink assessment. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a preferred embodiment of the method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to the present invention. Detailed Implementation

[0022] To enable those skilled in the art to understand the technical solution of the present invention more clearly, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0023] This invention proposes a method for generating non-component soil geochemical data based on the product of mass concentration and soil volume density. By converting mass concentration into soil chemical density, it breaks the constraint of summing component data. The specific technical solution is as follows: Mass concentration determination: Method overview: The mass concentration (MC) of major elements (such as Si, Al, Fe) and trace elements (such as Zn, Cu, Pb) in soil was determined using XRF and ICP-MS techniques.

[0024] Detailed steps: Sample preparation: Soil samples were collected, air-dried, and then ground to a particle size of less than 0.075 mm (200 mesh).

[0025] It was divided into two parts: one part was used for XRF (pressed into discs and melted into glass), and the other part was used for ICP-MS (acid digestion).

[0026] XRF testing (major elements): Instrumentation: Energy dispersive XRF spectrometer (e.g., PANalyticalAxios) is used.

[0027] Procedure: Press the ground sample into a disc with a diameter of 32 mm, place it in the sample chamber, excite X-rays, and record the fluorescence spectrum.

[0028] Calibration: Calibrate the instrument using a standard soil sample (such as NISTS RM2711) to generate a calibration curve.

[0029] Results: Output the mass fraction of major elements (e.g., SiO2%, Al2O3%), expressed as %.

[0030] ICP-MS test (trace elements): Pretreatment: Take 0.5g of sample, add 10mL of HNO3 and 2mL of HF, place in a sealed container and microwave digest (180°C, 30min).

[0031] Instrumentation: Inductively coupled plasma mass spectrometry (e.g., Agilent 7700x) was used.

[0032] Procedure: Dilute the digestion solution to 50 mL, add internal standards (such as Rh, In), and detect the elemental ion signals by ICP-MS.

[0033] Calibration: Use multi-element standard solutions (such as Merck Multi-element Standard VI) with a concentration range of 0.1-100 μg / L.

[0034] Results: Output the mass concentration of trace elements (such as Zn and Cu), expressed in mg / kg.

[0035] Calculation formula: XRF result correction: MC XRF =k·I+b; Where MCXRF is the mass concentration (%), I is the fluorescence intensity, and k and b are the slope and intercept of the calibration curve.

[0036] ICP-MS quantification: MC ICP-MS =Cs·V·D / m Where Cs is the concentration measured by the instrument (ug / L), V is the final solution volume (L), m is the sample mass (g), and D is the dilution factor.

[0037] Output: Major elements (e.g., SiO2 60%, Al2O3 20%).

[0038] Trace elements (such as Zn 50mg / kg, Cu 10mg / kg).

[0039] Soil bulk density acquisition: Soil bulk density (BD) was determined using existing methods, such as the ring sampler method. Use a fixed-volume ring cutter (volume such as 100cm³) to vertically press into undisturbed soil and take an undisturbed soil sample.

[0040] Remove excess soil from the outside of the ring cutter, ensure complete filling, collect soil samples, and place the soil-bearing ring cutter in a 105℃ oven to dry to constant weight (approximately 24-48 hours).

[0041] After cooling, weigh the M-ring cutter + dry soil and record the M-ring cutter value.

[0042] Calculate BD = (M ring cutter + dry soil - M ring cutter) ÷ ring cutter volume.

[0043] Scope of application: Soil density under natural conditions is 0.8–2.0 g / cm³, ensuring that the method is applicable to common soil types.

[0044] Soil chemical density calculation and non-component data generation: Based on MC and BD, calculate the soil chemical density (VC) of each component: VC = a × MC × BD; In the formula, VC represents soil chemical density, with units of mg / cm³. 3 .

[0045] 'a' is the unit conversion factor.

[0046] MC represents soil mass concentration, expressed as % or mg / kg, with corresponding a values ​​of 10 and 10, respectively. -3 .

[0047] BD represents soil density, measured in g / cm³.

[0048] Example: Nitrogen content 1% (0.01g nitrogen / g soil), BD 1.5g / cm³, then VCN = 10 × 1.5 = 15mg / cm³; Zinc content 50mg / kg, then VCZn = 50 × 10 -3 ×1.5=7.5×10 -2 mg / cm³.

[0049] Through this transformation, the VC of each component is expressed independently, without being constrained by the sum, and becomes non-component data.

[0050] Case 1: Calculation of soil chemical density of organic carbon (C-organic); A soil sample has a C-organic concentration of 22.56 g / kg and a bulk density of 1.2 g / cm³. What is its soil chemical density? 22.56 g / kg×1.2 g / cm³=27.072 mg / cm³; This value can be used to assess the carbon storage per unit area of ​​soil.

[0051] Pollution assessment: Calculate the total amount of pollution by combining soil volume.

[0052] Example: A contaminated site has an area of ​​1 hectare (10,000 m²) and a depth of 0.5 m. The cadmium concentration (VC) is 0.0075 mg / cm³. Therefore, the total cadmium content is: 0.0075 mg / cm³ × 10⁻⁶. 6cm³ / m³×10,000 m²×0.5 m=375,00000 mg=37.5kg.

[0053] The above description is merely a further embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A method for generating soil geochemical non-component data based on the conversion between mass concentration and volume density, characterized in that: Includes the following steps: a. Obtain soil samples; b. Determine the mass concentration of the target element in the soil sample, wherein the target element includes major elements and trace elements, the mass concentration of major elements is expressed as a mass fraction, and the mass concentration of trace elements is expressed as milligrams per kilogram; c. Determine the bulk density of the soil sample, in grams per cubic centimeter; d. Based on the mass concentration obtained in step b and the volume density obtained in step c, calculate the soil chemical density of the target element using the formula VC=a×MC×BD; Where VC is the soil chemical density, measured in milligrams per cubic centimeter, and a is the unit conversion factor; e. Use the soil chemical density as soil geochemical non-component data.

2. The method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to claim 1, characterized in that: In step b, the mass concentration of the major elements is determined by X-ray fluorescence spectroscopy, specifically including: Sample preparation: After air drying, the soil sample was ground to a particle size of less than 0.075 mm, and a portion of the sample was pressed into discs with a diameter of 32 mm. Instrument testing: The disc was tested using an energy-dispersive XRF spectrometer, which excited X-rays and recorded the fluorescence spectrum; The instrument was calibrated using standard soil samples to generate a calibration curve. The result is calculated using the formula. Calculate the mass concentration; in I is the mass concentration of the main element, I is the fluorescence intensity, and k and b are the slope and intercept of the calibration curve, respectively. In step b, the mass concentration of soil organic matter is determined by potassium dichromate oxidation-external heating method; Accurately weigh 0.1-0.5 g of air-dried soil sample that has passed through a 0.15 mm sieve, place it in a rigid test tube, and accurately add 0.8000 mol / L of [a specific solution] using a pipette. Add 10.00 mL of standard solution, then slowly add concentrated solution using a pipette. Add 15 mL of water and gently shake well. Place the test tube in a preheated oil bath and heat for 5 minutes. Remove the test tube and allow it to cool. Transfer the entire reaction solution to a 250 mL Erlenmeyer flask and rinse the test tube several times with distilled water. Pour the washings into the Erlenmeyer flask, keeping the total volume between 60-80 mL. Add 2-3 drops of o-phenanthroline indicator to the Erlenmeyer flask. Titrate the remaining potassium dichromate with 0.2 mol / L ferrous sulfate standard solution. The solution color will change from orange-yellow to blue-green to brownish-red. The titration endpoint is reached when the solution turns brownish-red. Soil organic matter (%) = (V0 - V) × C² × 0.003 × 1.724 × 1.08 × 100 / m³ V0: The volume (mL) of ferrous sulfate standard solution consumed during the blank titration test; V: Volume (mL) of ferrous sulfate standard solution consumed during soil sample titration; C2: Concentration of ferrous sulfate standard solution (mol / L); 0.003: The millimolecular mass (g / mmol) of 1 / 4 carbon atom; 1.724: Van Bemmelen coefficient. Assuming the average carbon content of soil organic matter is 58%, the coefficient for converting organic carbon to organic matter is approximately 100 / 58 ≈ 1.

724. 1.08: Oxidation correction factor, since the oxidation rate of organic carbon by this method is about 90%, it is corrected by dividing by 0.9; m: Mass of the air-dried soil sample (g); 100: Converts the result to a percentage.

3. The method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to claim 1, characterized in that: In step b, the mass concentration of trace elements is determined by inductively coupled plasma mass spectrometry, specifically including: sample pretreatment: take 0.5g of the ground soil sample, add... Add 2 mL of HF to a sealed container and microwave digest at 180 °C for 30 min. Dilute the digestion solution to 50 mL and add an internal standard. Inductively coupled plasma mass spectrometry was used to detect elemental ion signals in the digestion solution. Calibrate using multi-element standard solutions, with a calibration concentration range of 0.1-100 μg / L; Result calculation: using formula MC icp-ms The mass concentration is calculated as Cs·V·D / m, where MC icp-ms denoted as Cs, where Cs is the concentration of trace elements, V is the final solution volume, m is the sample mass, and D is the dilution factor.

4. The method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to claim 3, characterized in that: In step c, the soil bulk density is determined by the ring sampler method, specifically including: Sample collection was performed by vertically pressing a 100cm³ ring cutter into undisturbed soil to collect undisturbed soil samples and removing excess soil outside the ring cutter. The soil-containing ring cutter was placed in an oven at 105℃ and dried to constant weight. After cooling, the total mass of the ring cutter and dry soil, as well as the mass of the ring cutter, were weighed. The result was calculated using the formula BD=( ) ÷ V to calculate the bulk density, where This represents the total mass of the cutter head and dry soil. Let V be the mass of the ring cutter, and V be the volume of the ring cutter.

5. The method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to claim 4, characterized in that: The ring cutter method is suitable for naturally occurring soils with a bulk density of 0.8-2.0 g / cm³.

6. The method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to claim 5, characterized in that: In step d, the unit conversion factor a is: when MC is the mass concentration of the main element, a = 10; When MC is the mass concentration of trace elements .

7. The method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to claim 6, characterized in that: When the principal element is Furthermore, when its mass concentration is 60% and the soil volume density is 1.5 g / cm³, the corresponding soil chemical density VC = 10 × 60% × 1.5 = 90 mg / cm³.

8. The method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to claim 6, characterized in that: When the trace element is Zn with a mass concentration of 50 mg / kg and the soil bulk density is 1.5 g / cm³, the corresponding soil chemical density VC = 10. -3 ×50×1.5=0.075mg / cm³.

9. The method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to claim 8, characterized in that: In step e, the non-component data is used to break the summation constraint of traditional component data and avoid spurious correlations in data analysis.

10. The method for generating soil geochemical non-component data based on the conversion of mass concentration and volume density according to claim 9, characterized in that: The non-component data can be used for soil carbon storage assessment or total pollution calculation of contaminated sites: When assessing carbon storage, the carbon storage per unit area is calculated by combining the soil chemical density of organic carbon with soil volume. When calculating the total amount of pollution, the total amount of pollution is calculated by combining the soil chemical density of pollutants with the area and depth of the contaminated site.

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