A method and system for measuring soil erodible factors based on disintegration characteristics

Abstract

This invention discloses a method and system for calculating soil erodibility factors based on disintegration characteristics, comprising the following steps: acquiring several test samples with different dry densities, measuring the disintegration time of different samples, and calculating the disintegration rate of different samples based on the sample disintegration time; measuring the soil loss of several test samples with different dry densities, and calculating the soil erodibility factor of each sample based on the soil loss; and constructing a functional relationship between the erodibility factor and the disintegration rate based on the disintegration rate and soil erodibility factor of different samples. The method disclosed in this invention does not require long-term observation, requires minimal preliminary testing, has a low workload, and is time-efficient, thus accelerating data acquisition. It provides a scientific and convenient new technology and method for soil erosion research, soil loss calculation, and soil and water conservation.

Description

Technical Field

[0001] This invention belongs to the field of soil and water conservation technology, and relates to a method and system for calculating soil erodibility factors based on disintegration characteristics. Background Technology

[0002] Soil erodibility refers to the ease with which soil is broken up and moved under the influence of external forces such as raindrop impact and runoff erosion. Soil erodibility factor (K) is a basic physical property index of soil used to quantitatively reflect the magnitude of soil erodibility, and it forms the basis for quantitatively studying soil erosion characteristics and calculating soil loss. Due to the characteristics of loess—large porosity, unsaturation, and collapsibility—it is extremely prone to soil erosion under the influence of rainfall and runoff. The Loess Plateau is one of the regions in the world most severely affected by soil erosion. Therefore, studying the erodibility of loess and methods for measuring erodibility factor is of great significance for the prevention and control of soil erosion on the Loess Plateau.

[0003] Currently, the main methods for calculating soil erodibility factors include the standard runoff plot method, the nomograph method, and the formula method. However, all of these methods require extensive testing. For example, the standard runoff plot method requires the establishment of runoff plots and long-term observation; the nomograph method and the formula method both require measuring the soil particle composition and determining the organic matter content, resulting in a large workload and long testing period. Therefore, existing methods for calculating soil erodibility factors have disadvantages such as large workload, high cost, and long time consumption. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of existing methods for testing soil erodibility factors, which require a large amount of testing work, long-term observation, and are labor-intensive, costly, and time-consuming. This invention provides a method and system for calculating soil erodibility factors based on disintegration characteristics.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for calculating soil erodibility factors based on disintegration characteristics includes the following steps:

[0007] S1: Obtain several test samples with different dry densities, measure the disintegration time of different samples, and calculate the disintegration rate of different samples based on the sample disintegration time.

[0008] S2: Soil loss of several samples with different dry densities was measured, and the soil erodibility factor of each sample was calculated based on the soil loss.

[0009] S3: Construct a functional relationship between the erosion factor and the disintegration rate based on the disintegration rate and soil erosion factor of different samples.

[0010] A further improvement of the present invention is that:

[0011] Step S1 includes the following steps:

[0012] The dry density of the obtained samples was 1.20 g / cm³. 3 1.30g / cm 3 1.40 g / cm 3 1.50g / cm 3 1.60g / cm 3 and 1.70 g / cm 3 ;

[0013] The volume of each of the samples is 5 cm³. 3 .

[0014] In step S1, the disintegration rate of the sample is calculated using formula (1):

[0015]

[0016] Where t represents the sample disintegration time; V is the sample volume; and s represents the disintegration rate.

[0017] Step S2 includes the following steps:

[0018] Calculate soil loss at different levels of rainfall, and calculate the annual average soil loss based on the soil loss at different levels;

[0019] Calculate the rainfall erosivity at different levels of rainfall, and calculate the annual average rainfall erosivity factor based on the rainfall erosivity at different levels;

[0020] Soil erodibility factor is calculated based on average annual soil loss and average annual rainfall erosivity.

[0021] In step S2, the annual average soil loss is calculated using formula (2):

[0022] A = n1A1 + n2A2 + n3A3 (2)

[0023] Wherein, n1 represents the average number of rainfall events per year at the first rainfall level; A1 represents the soil loss corresponding to each rainfall event at the first rainfall level; n2 represents the average number of rainfall events per year at the second rainfall level; A2 represents the soil loss corresponding to each rainfall event at the second rainfall level; n3 represents the average number of rainfall events per year at the third rainfall level; and A3 represents the soil loss corresponding to each rainfall event at the third rainfall level.

[0024] The annual average rainfall erosivity factor is calculated using formula (3):

[0025] R = n1R1 + n2R2 + n3R3 (3)

[0026] Wherein, R1 represents the rainfall erosion force corresponding to the first rainfall level; R2 represents the rainfall erosion force corresponding to the second rainfall level; and R3 represents the rainfall erosion force corresponding to the third rainfall level.

[0027] In step S2, the soil erodibility factor is calculated using formula (4):

[0028] A = R × K × L × S × B × E × T (4)

[0029] Where A represents the average annual soil erosion; R represents the average annual rainfall erosivity factor; K represents the soil erodibility factor; L represents the slope length factor; S represents the slope factor; B represents biological measures for soil and water conservation; E represents engineering measures for soil and water conservation; and T represents tillage measures for soil and water conservation. The values ​​of B, E, and T are all 1.

[0030] In step S2, the different levels of rainfall include moderate rain, heavy rain, and rainstorm.

[0031] In step S3, a quadratic curve is used for fitting based on the soil disintegration rate and soil erodibility factor:

[0032] k = f(v) (5).

[0033] A loess erodibility factor calculation system based on disintegration characteristics includes a disintegration rate calculation module, a soil erodibility factor calculation module, and a function relationship construction module;

[0034] The disintegration rate calculation module is used to acquire several test samples with different dry densities, measure the disintegration time of different samples, and calculate the disintegration rate of different samples based on the sample disintegration time.

[0035] The soil erodibility factor calculation module is used to measure the soil loss of several samples with different dry densities and calculate the soil erodibility factor of each sample based on the soil loss.

[0036] The function relationship construction module is used to construct the function relationship between the erosion factor and the disintegration rate based on the disintegration rate and soil erosion factor of different samples.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This invention discloses a method for calculating soil erodibility factors based on disintegration characteristics. By testing the disintegration rate and erodibility factor of soils with different densities, a mathematical model is established between the disintegration rate and erodibility factor of loess. In practical applications, the erodibility factor of loess can be quickly calculated by measuring the disintegration rate of loess on-site, enabling rapid acquisition of prediction results and adaptability to field experiments. The method disclosed in this invention does not require long-term observation, requires minimal preliminary testing, has low workload, and is time-efficient, thus accelerating data acquisition. It provides a scientific and convenient new technology and method for soil erosion research, soil loss calculation, and soil and water conservation. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the process of the present invention;

[0041] Figure 2 This is a graph showing the relationship between the disintegration rate and the loess erodibility factor according to the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0047] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0048] The present invention will now be described in further detail with reference to the accompanying drawings:

[0049] See Figure 1 This invention discloses a method for calculating the erosibility factor of loess based on disintegration characteristics, which is used for scientific research on loess erosion and for calculating and assessing loess loss. The method mainly includes the following steps:

[0050] Step 1: Obtain several test samples with different dry densities, measure the disintegration time of different samples, and calculate the disintegration rate of different samples based on the sample disintegration time.

[0051] Furthermore, in this embodiment of the invention, the dry density was measured to be 1.20 g / cm³ using a soil disintegration tester. 3 1.30g / cm 3 1.40 g / cm 3 1.50g / cm 3 1.60g / cm 3 and 1.70 g / cm 3 The disintegration rate (v) of the loess sample;

[0052] The volume of each soil sample was 5 cm³. 3The natural moisture content is 14%.

[0053] Furthermore, the disintegration rate of the sample is calculated using formula (1):

[0054]

[0055] Step 2: Measure the soil loss of several samples with different dry densities, and calculate the soil erodibility factor for each sample based on the soil loss.

[0056] The amount of soil erosion in the Loess Plateau was tested by artificially simulating rainfall.

[0057] Step 201:

[0058] During simulated rainfall, rainfall is divided into three levels according to rainfall intensity: moderate rain, heavy rain, and torrential rain. In this embodiment of the invention, the levels of moderate rain, heavy rain, and torrential rain are respectively the first rainfall level, the second rainfall level, and the third rainfall level.

[0059] Simulated rainfall was conducted to calculate the annual soil loss and average annual erosivity per rainfall event for each rainfall level.

[0060] Furthermore, the annual average soil loss is calculated using formula (2):

[0061] A = n1A1 + n2A2 + n3A3 (2)

[0062] In the formula: A represents the annual soil loss, t / hm 2 n1 represents the average number of moderate-rainfall events per year in a certain area; A1 represents the soil loss corresponding to each moderate-rainfall event in the simulated rainfall experiment, in t / hm². 2 n2 represents the average number of heavy rainfall events per year in a certain area; A2 represents the soil loss corresponding to each heavy rainfall event in the simulated rainfall experiment, in t / hm². 2 n3 represents the average number of heavy rainstorms per year in a certain area; A3 represents the soil loss corresponding to each heavy rainstorm in the simulated rainfall experiment, in t / hm². 2 ;

[0063] Furthermore, the annual average rainfall erosivity factor is calculated using formula (3):

[0064] R = n1R1 + n2R2 + n3R3 (3)

[0065] Where R represents the annual rainfall erosivity, MJ·mm / (hm²) 2 R1 represents the rainfall erosivity corresponding to each rainfall event in the simulated rainfall experiment, in MJ·mm / (hm). 2 R² represents the rainfall erosivity corresponding to a heavy rainfall event in the simulated rainfall experiment, in MJ·mm / (hm²). 2R3 represents the rainfall erosivity corresponding to a single rainfall event in the simulated rainfall experiment, in MJ·mm / (hm). 2 ·h).

[0066] Step 202:

[0067] For calculating soil erodibility factors, since the soil tanker was placed without water conservation measures, factors B, E, and T were all set to 1. The slope length factor LS was revised using an equation.

[0068] A = R × K × L × S × B × E × T (4)

[0069] Where A represents the annual average soil loss, mainly referring to the multi-year average soil loss caused by slope erosion under the action of rainfall and runoff, t / (hm). 2 ·a); R is the rainfall erosivity factor, (MJ·mm) / (hm 2 ·h·a); K is the soil erodibility factor (t·hm). 2 ·h) / (hnl 2 ·MJ·mm); LS is the topographic factor, where L is the slope length factor and S is the slope gradient factor; B is the biological measures for soil and water conservation; E is the engineering measures for soil and water conservation; T is the tillage measures for soil and water conservation; L, S, B, E and T are dimensionless factors.

[0070] Furthermore, depending on the slope, different revised formulas are used for the slope factor:

[0071] S=10.8sinθ+0.03 θ≤5° (6)

[0072] S=16.8sinθ-0.50 5°≤θ<10° (7)

[0073] S=21.9sinθ-0.96 θ≥10° (8)

[0074] Furthermore, when the runoff plot is not a standard plot, the slope length needs to be revised:

[0075]

[0076]

[0077] Step 3: Construct a functional relationship between the erosion factor and the disintegration rate based on the disintegration rate and soil erosion factor of different samples.

[0078] Based on steps 1 and 2, regression analysis was performed on the soil disintegration rate and the corresponding soil erodibility factor K value under different bulk density rainfall test conditions, resulting in a linear relationship between the soil erodibility factor and the soil disintegration rate. (See attached diagram.) Figure 2 :

[0079] k=f(v) (5)

[0080] In engineering practice, when calculating the loess erodibility factor, undisturbed soil is taken as needed, cut into cubic samples with a side length of 5cm using a soil cutter, and its disintegration rate (v) is measured using a disintegration tester. The formula k = f(v) is used to calculate the loess erodibility factor (k).

[0081] The present invention also discloses a specific embodiment:

[0082] The soil samples from a certain location were used for the experiment. The soil density data of the surface layer of the test station is shown in Table 1. The average number of days with rainfall of three levels (moderate rain, heavy rain, and torrential rain) and the average annual erosivity of rainfall are shown in Table 2. The rainfall level characteristics are shown in Table 2.

[0083] Table 1. Soil density data of the top layer (0-30cm) at Linghou Experimental Station, Yangling District

[0084]

[0085] Based on the daily and hourly rainfall data from a monitoring station in a certain area from 2016 to 2020, and the annual average number of rainfall days and the annual average erosivity of rainfall events at three levels (moderate rain, heavy rain, and torrential rain), rainfall intensities were set at 25 mm / h, 45 mm / h, and 90 mm / h, with a rainfall duration of 66 minutes. After the rainfall started on the slope, data was collected every minute for the first 3 minutes, and then every 3 minutes at the soil trough interface, with the velocity measured once. See Table 2.

[0086]

[0087] Step 1: Based on the above data statistics, take soil samples as needed and prepare them to a volume of 5 cm³. 3 The moisture content was 14%, and the dry densities were 1.20, 1.30, 1.40, 1.50, and 1.60 g / cm³, respectively. 3 For loess samples, the time t for complete disintegration of the loess sample was determined using a soil disintegration tester, and then the disintegration rate was calculated using the disintegration rate formula. The calculated disintegration rates at different dry densities are shown in Table 3.

[0088] Table 3. Disintegration rate of soil samples at different dry densities

[0089]

[0090] Step 2: Table 4 shows the soil erodibility factor K values ​​calculated using artificial rainfall simulation test data and rainfall events of various levels in Yangling District (Table 2). The calculation formula is based on the soil erosion calculation formula. According to the conditions specified in the Chinese Soil Erosion Equation, B, E, and T are all taken as 1 in this study. As shown in Table 4, the values ​​are 1.2, 1.3, 1.4, and 1.5 g / cm³. 3 The average soil erodibility K values ​​under the given soil bulk density were 0.0254, 0.0212, 0.0186, and 0.0177 t.hm. 2 h / (hm 2 .MJ.mm).

[0091] Table 4. Soil erodibility K value calculated based on simulated rainfall experiments.

[0092]

[0093] Step 3: Based on the disintegration rate v and soil erodibility factor k under different soil dry densities, a quadratic curve was used for fitting, with a correlation coefficient above 0.95. The fitting results are shown in [link to fitting results]. Figure 2 .

[0094] Relationship between disintegration rate v and soil erodibility factor k:

[0095] k=0.0147+0.000125x-5.1203e-08x 2 (11)

[0096] By collecting undisturbed soil from the Machaoling test station, preparing it into a cube with a volume of 5 cm3, and conducting a disintegration test, the obtained disintegration rate was substituted into formula (11) to calculate the soil erodibility factor k = 0.0177.

[0097] The method disclosed in this invention saves time, reduces workload, and provides a quick and convenient method for calculating soil erosion in the Loess Plateau.

[0098] This invention discloses a loess erodibility factor calculation system based on disintegration characteristics, including a disintegration rate calculation module, a soil erodibility factor calculation module, and a function relationship construction module;

[0099] The disintegration rate calculation module is used to acquire several test samples with different dry densities, measure the disintegration time of different samples, and calculate the disintegration rate of different samples based on the sample disintegration time.

[0100] The soil erodibility factor calculation module is used to measure the soil loss of several samples with different dry densities and calculate the soil erodibility factor of each sample based on the soil loss.

[0101] The function relationship construction module is used to construct the function relationship between the erosion factor and the disintegration rate based on the disintegration rate and soil erosion factor of different samples.

[0102] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calculating soil erodibility factors based on disintegration characteristics, characterized in that, Includes the following steps: S1: Obtain several test samples with different dry densities, measure the disintegration time of different samples, and calculate the disintegration rate of different samples based on the sample disintegration time. S2: Soil loss of several samples with different dry densities was measured, and the soil erodibility factor of each sample was calculated based on the soil loss. S3: Construct a functional relationship between the erosion factor and the disintegration rate based on the disintegration rate and soil erosion factor of different samples; In step S3, a quadratic curve is used for fitting based on the soil disintegration rate and soil erodibility factor: Where v represents the disintegration rate; k represents the soil erodibility factor; Step S2 includes the following steps: Calculate soil loss at different levels of rainfall, and calculate the annual average soil loss based on the soil loss at different levels; Calculate the rainfall erosivity at different levels of rainfall, and calculate the annual average rainfall erosivity factor based on the rainfall erosivity at different levels; Soil erodibility factor is calculated based on annual average soil loss and annual average rainfall erosivity. In step S2, the annual average soil loss is calculated using formula (2): Wherein, n1 represents the average number of rainfall events per year at the first rainfall level; A1 represents the soil loss corresponding to each rainfall event at the first rainfall level; n2 represents the average number of rainfall events per year at the second rainfall level; A2 represents the soil loss corresponding to each rainfall event at the second rainfall level; n3 represents the average number of rainfall events per year at the third rainfall level; and A3 represents the soil loss corresponding to each rainfall event at the third rainfall level.

2. The method for calculating soil erodibility factors based on disintegration characteristics according to claim 1, characterized in that, Step S1 includes the following steps: The dry density of the obtained samples was 1.20 g / cm³. 3 1.30g / cm 3 1.40g / cm 3 1.50g / cm 3 1.60g / cm 3 and 1.70 g / cm 3 ; The volume of each of the samples is 5 cm³. 3 .

3. The method for calculating soil erodibility factors based on disintegration characteristics according to claim 1, characterized in that, In step S1, the disintegration rate of the sample is calculated using formula (1): Where t represents the sample disintegration time; denoted as sample volume; s represents the disintegration rate.

4. The method for calculating soil erodibility factors based on disintegration characteristics according to claim 1, characterized in that, The annual average rainfall erosivity factor is calculated using formula (3): Wherein, n1 represents the average number of rainfall events per year at the first rainfall level; n2 represents the average number of rainfall events per year at the second rainfall level; n3 represents the average number of rainfall events per year at the third rainfall level; R1 represents the rainfall erosivity corresponding to the rainfall at the first rainfall level; R2 represents the rainfall erosivity corresponding to the rainfall at the second rainfall level; and R3 represents the rainfall erosivity corresponding to the rainfall at the third rainfall level.

5. The method for calculating soil erodibility factors based on disintegration characteristics according to claim 1, characterized in that, In step S2, the soil erodibility factor is calculated using formula (4): in, This represents the average annual soil erosion. This represents the annual average rainfall erosivity factor; Indicates soil erodibility factor; Indicates the slope length factor; Indicates the slope factor; Indicates biological measures for soil and water conservation; Indicates soil and water conservation engineering measures; Soil and water conservation farming measures, , , All values ​​are 1.

6. The method for calculating soil erodibility factors based on disintegration characteristics according to claim 1, characterized in that, In step S2, the different levels of rainfall include moderate rain, heavy rain, and rainstorm.

7. The calculation system for a method of calculating soil erodibility factors based on disintegration characteristics according to claim 1, characterized in that, It includes a disintegration rate calculation module, a soil erodibility factor calculation module, and a function relationship construction module; The disintegration rate calculation module is used to acquire several test samples with different dry densities, measure the disintegration time of different samples, and calculate the disintegration rate of different samples based on the sample disintegration time. The soil erodibility factor calculation module is used to measure the soil loss of several samples with different dry densities and calculate the soil erodibility factor of each sample based on the soil loss. The function relationship construction module is used to construct the function relationship between the erosion factor and the disintegration rate based on the disintegration rate and soil erosion factor of different samples.

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