Device for rapidly and accurately measuring biological crust soil roughness

Abstract

The invention discloses a device for rapidly and accurately measuring the roughness of biological crust soil, and belongs to the technical field of field measurement equipment. The device comprises two metal rods, a probe unit and a resistance wire, the bottom of the metal rod can be vertically arranged on the earth surface to be measured, a plurality of probe units which are vertically arranged in parallel at equal intervals are arranged in the middle of the metal rod, and plastic plates are mounted on, in and under the metal rod for fixing; the resistance wire sequentially penetrates through the upper parts of the probe units, one end of the resistance wire is welded with the metal rod, and the other end is connected with the pulley which is arranged on the bottom plastic plate. The device can be arranged on the biological crust earth surface, the resistance value of the resistance wire in the initial stage and the measurement stage is obtained by measuring the voltage at the two ends of the resistance wire, the change of the length of the resistance wire is calculated, and finally the earth surface roughness of the biological crust soil is obtained. According to the invention, the biological crust surface roughness is measured by using the change of the voltage, the measurement is rapid and accurate, the operation is simple and convenient, the carrying is convenient, and the method is suitable for rapid measurement of the field biological crust soil surface roughness.

Description

Technical Field

[0001] The invention belongs to the technical field of field measurement equipment and relates to a device for quickly and accurately measuring the roughness of biological crust soil. Background Art

[0002] As an important part of field investigation, soil surface roughness is an important indicator that affects surface runoff and erosion processes. Generally, surface roughness is the phenomenon of surface undulation and unevenness formed by the combined effects of factors such as crop planting and its management measures, human activities and soil erosion. It is one of the main physical properties of the ground and the main controlling factor of land surface processes such as rainfall infiltration, surface runoff, wind erosion and water erosion. Soil surface roughness reflects the micro-geomorphology of the surface and is an essential parameter for simulating and predicting the process of soil and water loss and the migration and transformation of pollutants.

[0003] At present, the commonly used soil surface roughness measurement methods can be generally divided into two categories: non-contact measurement technology and contact measurement technology. Among them, the non-contact measurement technology has a high measurement accuracy and automation level, mainly including image analysis method and remote sensing technology. For example, the image analysis method refers to taking an image of the soil surface, analyzing the image using image processing software, extracting the contour information of the soil surface, and then obtaining the soil roughness. Remote sensing technology refers to using remote sensing satellites or drones and other platforms to obtain surface images, and extracting the roughness information of the soil surface through remote sensing image processing and analysis technology. Correspondingly, contact measurement mainly includes chain method and probe method, etc., and the instrument structure is usually simple and the price is low. Among them, the chain method refers to placing a chain of fixed length on the surface, and measuring the surface roughness by measuring the relationship between the horizontal length of the chain and the actual length. The probe method uses a row of equally spaced and equally long probes that can move up and down, and the probe head contacts the surface. The surface contour is drawn by recording the position of the probe tail, and the surface roughness is calculated.

[0004] Biological crust is a special complex with a certain thickness formed by the cementation of microorganisms such as microorganisms, blue-green algae, lichens, mosses and soil particles. It plays an important role in fragile ecosystems. Studies have shown that biological components such as algae and bacteria in biological crusts can promote soil nutrient cycling and increase soil formation rate through their physiological metabolism. While changing soil properties (such as microtopography), it also affects surface roughness, thus profoundly affecting the physical, chemical and biological processes of the soil. Understanding the changes in surface roughness during the development of biological crust soil and its influencing factors is of great significance for clarifying its role in changing soil structure, surface eco-hydrological processes and capacity conversion characteristics.

[0005] Although the above-mentioned non-contact measurement technology and contact measurement technology can be used to measure the roughness of biological crust soil, the non-contact measurement technology equipment is large, cumbersome to operate, and expensive; and affected by various factors, it requires professional image processing software and technical support, which is not suitable for the rapid development of field investigations. Compared with non-contact measurement technology, the instrument structure of contact measurement technology is simple, low-cost, and easy to carry, which is more suitable for rapid measurement of biological crust soil roughness in field surveys. However, the existing methods are relatively complicated to operate, the measurement process is greatly affected by human experience, and may cause certain damage to the soil. In summary, although there are studies on the measurement of biological crust soil roughness, there are still deficiencies in the development of equipment that can accurately and quickly measure the roughness of biological crust soil in the field. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a device that can quickly and accurately measure the roughness of biological crust soil, so as to provide a reference for exploring the influence of biological crust on surface erosion, runoff generation process and eco-hydrological process.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A device for quickly and accurately measuring the roughness of biological crust soil comprises two metal rods with adjustable lengths, a top short plastic plate, a middle short plastic plate, a bottom long plastic plate, a plurality of measuring needle units, a resistance wire as a measurement reference, and a pulley. The plurality of measuring needle units are a plurality of plastic needles of equal length; the top short plastic plate, the middle short plastic plate, and the bottom long plastic plate are horizontally mounted on two metal rods; the middle short plastic plate and the bottom long plastic plate are provided with holes for the measuring needle units to pass through, and the measuring needle units pass through the middle short plastic plate and the bottom long plastic plate and are arranged in parallel and equidistantly between the two metal rods; one end of the bottom long plastic plate extends beyond a part of the metal rod; the upper part of the measuring needle unit and a metal rod is provided with a threading hole for the resistance wire to pass through; the pulley is fixed on the part of the bottom long plastic plate that extends beyond the metal rod; one end of the resistance wire is fixed on the metal rod, and the other end passes through the measuring needle unit and the metal rod with the threading hole and is wound around the pulley.

[0009] The height of the metal rod can be adjusted according to the actual situation of the ground surface, and the bottom is preferably a conical needle structure, which is easy to install and fix on the ground surface to be measured; a preferred size of the metal rod is: 20.0 cm in height and 0.5 cm in diameter.

[0010] The materials of the top short plastic plate, the middle short plastic plate, the bottom long plastic plate and the measuring needle unit are preferably polyvinyl chloride; the top short plastic plate is used to support the measuring needle unit to prevent the measuring needle unit from falling out, and as a reference for whether the top of the measuring needle unit is parallel; the middle short plastic plate is used to fix the measuring needle unit, and its interior is perforated and the inner wall is smooth, and the number of holes corresponds to the measuring needle unit one by one; the bottom long plastic plate is used to fix the measuring needle unit and the pulley, and the number of internal holes corresponds to the middle plastic plate one by one and the inner wall is smooth; a preferred size of the top short plastic plate, the middle short plastic plate and the bottom long plastic plate is: the top short plastic plate is 25.0 cm long, 2.0 cm wide and 0.5 cm thick, the middle short plastic plate is 25.0 cm long, 2.0 cm wide and 5.0 cm thick, and the bottom long plastic plate is 35.0 cm long, 2.0 cm wide and 0.5 cm thick; a preferred size of the measuring needle unit is: 15.0 cm long, 0.1 cm in diameter, and the distance between needles is 0.1 cm.

[0011] A rubber support is provided at the bottom of the probe unit to prevent the bottom of the probe unit from entering the soil and causing deviation in the measured value; a preferred size of the rubber support is: 0.5 cm in length and 0.1 cm in width.

[0012] The resistance wire is preferably made of nickel-chromium alloy with a smooth surface, and is preferably fixed to the metal rod by welding; a preferred size of the resistance wire is: 0.05 cm in diameter.

[0013] The pulley is further provided with a screw; the pulley is used to wind the resistance wire, and the screw on the pulley is used to adjust the length of the resistance wire. After all the measuring needle units are fixed in position, the resistance wire can be straightened by rotating the screw on the pulley to restore all the measuring needle units to their original positions.

[0014] The device for measuring the roughness of biological crust soil is used in measuring the surface roughness of biological crust soil.

[0015] The method for measuring the surface roughness of biological crust soil using the above-mentioned device for measuring the roughness of biological crust soil comprises the following steps: inserting two metal rods into the soil body so that the device is horizontal and the highest position of the surface protrusion is in contact with the probe unit; tightening the pulley screw to straighten the resistance wire so that all the probe units are located at the same horizontal position and are parallel and equidistant to the top short plastic plate; the top ends of the two metal rods are connected to the power supply device and the data collector through wires, and the voltage value V at both ends of the resistance wire is measured by the data collector at this time 1 ; Then, loosen the pulley screw to loosen the resistance wire, press the probe unit vertically downward until the rubber support at the bottom of each probe unit is close to the soil surface, tighten the pulley screw to make the resistance wire consistent with the contour connection shape of the top of the probe unit, and measure the voltage value V at both ends of the resistance wire through the data logger 2 ;

[0016] According to Ohm's law Apply the same current I and calculate the resistance R of the resistor wire 1 , R 2 ;

[0017] According to the law of resistance Where ρ is the resistivity, S is the cross-sectional area, and the length of the resistance wire before and after the measurement is calculated to be L 1 , L 2 ;

[0018] The relationship between the change in resistance wire length and soil roughness is Cr = (1-L 1 / L 2 )×100, and determine the surface roughness Cr of the biological crust soil.

[0019] Advantages and beneficial effects of the present invention: The present invention measures the voltage at both ends of the resistance wire, obtains the resistance value of the resistance wire in the initial stage and the measurement stage, calculates the change in the length of the resistance wire and finally obtains the surface roughness of the biological crust soil. The present invention uses the change in voltage to measure the roughness of the biological crust soil. The measurement is fast and accurate, the operation is simple and easy to carry, and it is suitable for the rapid measurement of the surface roughness of the biological crust soil in the field. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the surface roughness measuring device of the present invention;

[0021] Figure 2 It is a schematic structural diagram of a probe unit of a surface roughness measuring device of the present invention;

[0022] Figure 3 The results of measuring the surface roughness by the surface roughness measuring device of the present invention and the traditional chain method are compared;

[0023] In the figure: 1-metal rod, 2-metal rod, 3-top short plastic plate, 4-middle short plastic plate, 5-bottom long plastic plate, 6-probe unit, 7-rubber drag, 8-resistance wire, 9-pulley, 10-screw, 11-electric wire. DETAILED DESCRIPTION

[0024] The structure of the device of the present invention and the principle and method for measuring the roughness of biological crust soil are further described in detail below in conjunction with the embodiments and drawings.

[0025] Example 1

[0026] The present invention provides a device for quickly and accurately measuring the roughness of biological crust soil, the structure of which is as follows: Figure 1-2As shown, it includes two metal rods (metal rod 1 and metal rod 2) with adjustable length, a top short plastic plate 3, a middle short plastic plate 4, a bottom long plastic plate 5, a plurality of measuring needle units 6, a rubber support 7, a resistance wire 8 as a measurement reference, and a pulley 9. The top short plastic plate 3, the middle short plastic plate 4, and the bottom long plastic plate 5 are horizontally installed on the two metal rods, and one end of the bottom long plastic plate 5 exceeds a part of the metal rod 2. The bottom of the metal rod is a conical needle structure, which is easy to install and fix on the surface to be measured. The plurality of measuring needle units 6 are a plurality of plastic needles of equal length. The middle short plastic plate 4 and the bottom long plastic plate 5 are also provided with holes for the measuring needle units 6 to pass through so that the measuring needle units 6 can slide up and down. The measuring needle units 6 pass through the middle short plastic plate 4 and the bottom long plastic plate 5 and are arranged in parallel and equidistantly between the two metal rods. The upper part of the measuring needle unit 6 is provided with a threading hole for the resistance wire 8 to pass through, and the lower end of the measuring needle unit 6 is installed with a rubber support 7. The upper part of the metal rod 2 is provided with a hole for the resistance wire 8 to pass through. The pulley 9 is fixed to the end of the bottom long plastic plate 5 that extends beyond the metal rod 2. One end of the resistance wire 8 is welded and fixed to the metal rod 1, and the other end passes through the probe unit 6 and the metal rod 2 and is wound around the pulley 9. The pulley 9 is provided with a screw 10 that can adjust the length of the resistance wire 8. The top ends of the two metal rods are connected to electric wires 11, which can be connected to an external power supply device and a data acquisition device.

[0027] A preferred size specification of the device for quickly and accurately measuring the roughness of biological crust soil is as follows: the adjustable length metal rod is 20.0 cm high and 0.5 cm in diameter, and the height of the metal rod can be adjusted according to the actual situation of the surface; the top short plastic plate 3, the middle short plastic plate 4, and the bottom long plastic plate 5 are polyvinyl chloride plastic plates; the top short plastic plate is 25.0 cm long, 2.0 cm wide, and 0.5 cm thick; the middle short plastic plate is 25.0 cm long, 2.0 cm wide, and 5.0 cm thick; the bottom long plastic plate is 35.0 cm long, 2.0 cm wide, and 0.5 cm thick; the measuring needle unit 6 is a plurality of black polyvinyl chloride plastic needles of equal length, each plastic needle is 15.0 cm long and 0.1 cm in diameter, and the distance between the needles is 0.1 cm; the rubber support 7 is 0.5 cm long and 0.1 cm wide; the resistance wire 8 is made of nickel-chromium alloy, has a smooth surface, and has a diameter of 0.05 cm.

[0028] The present invention obtains the voltage difference between the resistance wire in the middle of the metal rod before and after the measurement, and calculates the difference in the change in the length of the resistance wire. Finally, the surface roughness of the biological crust soil is calculated through the relationship equation between the change in the length of the resistance wire and the surface roughness. The use method of the device of the present invention and the calculation process of the roughness of the biological crust soil are as follows.

[0029] According to the actual roughness of the surface to be measured, the length of the metal rods 1 and 2 is adjusted to make the main body of the measuring device at an appropriate height, and the conical needle-shaped metal rod at the bottom is vertically inserted into the surface to be measured, ensuring that the metal rods on both sides are inserted into the soil and the device is horizontal. The device should not be too high to cause excessive deformation of the resistance wire during the downward pressure of the probe unit 8, and it should not be too short to cause a large amount of rubber support 7 at the bottom of the probe unit 6 to contact the surface to be measured before measurement, causing errors. It should be ensured that the highest position of the surface protrusion contacts the probe unit.

[0030] Secondly, check whether the resistance wire 8 passes through the threading holes on the upper part of the measuring needle unit 6 in sequence. Here, a device with 100 measuring needle units is taken as an example. The measuring needle units 6 are 100 black plastic needles of equal length, 15.0 cm long, 0.1 cm in diameter, and the distance between two adjacent needles is 0.1 cm. Ensure that the 100 measuring needle units can move vertically on the middle short plastic plate 4 and the bottom long plastic plate 5, the upper end of the measuring needle unit 6 is outside the top of the middle short plastic plate 4, and does not touch the top short plastic plate 3, and the lower end can fall on the surface to be measured after passing through the bottom of the bottom long plastic plate 5. After checking that everything is correct, adjust the resistance wire 8 by rotating the screw 10 of the pulley 9, tighten the screw to straighten the resistance wire 8 and restore the 100 measuring needle units to their original positions, so that all the measuring needle units 6 are in the same horizontal position and parallel and equidistant from the top short plastic plate 3. The top ends of the two metal rods are connected to the power supply device and the data collector through the wire 11, and the voltage value V at both ends of the resistance wire is measured by the data collector. 1 .

[0031] After that, loosen the pulley screw 10 to release the resistance wire 8, and press the probe unit 6 vertically downward until the rubber support 7 at the bottom of each probe unit is close to the soil surface. The force should not be too heavy to cause the rubber support to sink into the soil and cause deviation, and it should also be avoided that the probe unit 6 is suspended in the air and causes errors. After 100 probe units 6 are fully in contact with the surface to be measured, slightly tighten the pulley screw 10 so that the resistance wire 8 can be consistent with the contour connection shape of the top of the probe unit 6, and the voltage value V at both ends of the resistance wire is measured by the data acquisition device. 2 According to Ohm's law (1), when the same current I is applied, the resistance of the resistor wire R can be calculated. 1 , R 2 .

[0032]

[0033] According to the resistance law (2), the length of the resistance wire before and after the measurement is calculated to be L 1 , L 2 Finally, the surface roughness Cr of the biological crust soil can be quickly and accurately determined through the relationship equation (3) between the change in resistance wire length and soil roughness.

[0034]

[0035] Wherein ρ is resistivity, S is cross-sectional area, both of which are related to the material of the resistance wire used. The resistance wire used in the present invention is made of nickel-chromium alloy, has a smooth surface and a diameter of 0.05 cm.

[0036] Cr=(1-L 1 / L 2 )×100 (3)

[0037] In summary, the present invention provides a device for quickly and accurately measuring the surface roughness of biological crust soil, which mainly includes metal rods 1 and 2, a probe unit 6, a rubber support 7, a resistance wire 8, three plastic plates 3, 4, 5 and a pulley 9. The metal rods 1 and 2 can be vertically fixed to the surface to be measured to fix the device, and a plurality of probe units 6 arranged in parallel and equidistantly are arranged between the metal rods 1 and 2. The resistance wire 8 passes through the probe units in sequence, which can simulate the real shape of the surface contour to be measured. The resistance wire 8 and the probe unit 6 can measure the surface roughness to be measured by the chain method and the probe method. At the same time, by measuring the difference in voltage between the two ends of the resistance wire before and after, the difference in resistance value and length change of the resistance wire is calculated, and finally, the relationship equation between the resistance wire length difference and the surface roughness is used to achieve rapid and accurate measurement of the surface roughness of biological crust soil. In addition, the two-dimensional plane surface roughness can also be obtained through multiple measurements.

[0038] Example 2

[0039] In August 2024, three sample plots (moss crust sandy soil, algae-moss mixed sandy soil, and algae crust sandy soil) were selected in typical biocrust sandy soil in the northern Loess Plateau of China, and each sample plot was repeated 5 times. The surface roughness of the biocrust soil was measured using the traditional chain method and the device of the present invention.

[0040] Preliminary work: Before measuring, check whether the resistance wire passes through the threading holes on the top of all the probe units in sequence, and ensure that all the probe units can be movably mounted vertically on the plastic plates in the middle and bottom. After checking, adjust the resistance wire by rotating the screw of the pulley, tighten the screw to straighten the resistance wire and restore the probe unit to its original position, so that all the probe units are in the same horizontal position and parallel and equidistant from the top plastic plate. Clear the dead branches and leaves on the surface of the selected soil, adjust the two adjustable length metal rods according to the actual roughness of the surface to be measured, so that the main body of the measuring device is at an appropriate height, and vertically insert the tapered needle-shaped metal rod at the bottom into the surface to be measured, ensuring that the metal rods on both sides are inserted into the soil and the device is horizontal.

[0041] Measurement process: First, a CR3000 data logger (Campbell Scientific, Inc., USA) was used to record the voltage value at both ends of the resistance wire when it was in the initial state. After that, the pulley screw was loosened to loosen the resistance wire, and the probe unit was pressed vertically downward until the rubber drag at the bottom of each probe unit was close to the soil surface. After the probe unit was fully in contact with the surface to be measured, the pulley screw was slightly tightened so that the resistance wire could be consistent with the contour connection shape of the top of the probe unit, and the voltage value at both ends of the resistance wire was measured by the data logger.

[0042] Data processing: The voltage difference between the two ends of the resistance wire before and after the measurement is obtained through the data acquisition device, and the resistance difference of the resistance wire before and after the measurement is obtained, which is then converted into the change value of the resistance wire length, and finally the final roughness of the soil surface is calculated.

[0043] In addition, the conventional chain method (silver, 20 cm long, 0.1 cm in diameter) was used to measure the roughness of the soil of the biological crust in the same sample plot. The results of the conventional chain method and the device of the present invention ( Figure 3 ) shows: for the roughness measurement of the same biological crust soil sample, the traditional chain method may be subject to large human reading errors (up to one decimal place can be estimated), while the device of the present invention can accurately measure the change in resistance based on the resistance wire fitting the surface undulations, thereby obtaining the surface roughness (the measurement result can be accurate to three decimal places). This is reflected in the specific results. For example, in the moss crust measurement, the maximum value measured by the traditional chain method is 5.8, and the minimum value is 4.1, with a difference of 1.7 between the maximum and minimum values; while the maximum value measured by the device of the present invention is 5.323, and the minimum value is 4.213, with a difference of only 1.11 between the maximum and minimum values. In summary, the device of the present invention can obtain the surface roughness of biological crust soil more quickly and accurately.

[0044] The above embodiments are provided for the purpose of illustration and description in order to better illustrate the principles and practical applications of the present invention. They are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the invention.

Claims

1. A device for quickly and accurately measuring the roughness of biological crust soil, characterized by: It includes two metal rods with adjustable lengths, a short plastic plate at the top, a short plastic plate in the middle, a long plastic plate at the bottom, a plurality of measuring needle units, a resistance wire, and a pulley; the plurality of measuring needle units are a plurality of plastic needles of equal length; The top short plastic plate, the middle short plastic plate and the bottom long plastic plate are horizontally mounted on two metal rods; The middle short plastic plate and the bottom long plastic plate are provided with holes for the probe unit to pass through, and the probe unit passes through the middle short plastic plate and the bottom long plastic plate and is arranged in parallel and equidistantly between the two metal rods; one end of the bottom long plastic plate extends beyond a portion of the metal rod; The probe unit and a metal rod are provided with threading holes for the resistance wire to pass through on the upper part; the pulley is installed on the part of the bottom long plastic plate that exceeds the metal rod; one end of the resistance wire is fixed on the metal rod, and the other end passes through the probe unit and the metal rod with the threading hole and is wound around the pulley.

2. The device for quickly and accurately measuring the roughness of biological crust soil according to claim 1 is characterized in that: The bottom of the metal rod is a conical needle structure.

3. The device for rapidly and accurately measuring the roughness of biological crust soil according to claim 1, characterized in that: The top short plastic plate, the middle short plastic plate, the bottom long plastic plate and the measuring needle unit are made of polyvinyl chloride.

4. The device for rapidly and accurately measuring the roughness of biological crust soil according to claim 1, characterized in that: A rubber support is provided at the bottom of the measuring needle unit.

5. The device for rapidly and accurately measuring the roughness of biological crust soil according to claim 1, characterized in that: The resistance wire is made of nickel-chromium alloy.

6. The device for rapidly and accurately measuring the roughness of biological crust soil according to claim 1, characterized in that: The pulley is provided with a screw.

7. The device for quickly and accurately measuring the roughness of biological crust soil according to any one of claims 1 to 6, characterized in that: The metal rod is 20.0 cm high and 0.5 cm in diameter; the top short plastic plate is 25.0 cm long, 2.0 cm wide and 0.5 cm thick; the middle short plastic plate is 25.0 cm long, 2.0 cm wide and 5.0 cm thick; the bottom long plastic plate is 35.0 cm long, 2.0 cm wide and 0.5 cm thick; The measuring needle unit is 15.0 cm long and 0.1 cm in diameter, and the distance between the needles is 0.1 cm; The resistance wire has a diameter of 0.05 cm.

8. The device for rapidly and accurately measuring the roughness of biological crust soil according to claim 4, characterized in that: The rubber support is 0.5 cm long and 0.1 cm wide.

9. Use of the device for rapidly and accurately measuring the roughness of biological crust soil according to any one of claims 1 to 8 in measuring the surface roughness of biological crust soil.

10. A method for measuring the surface roughness of biological crust soil using the device for quickly and accurately measuring the roughness of biological crust soil according to any one of claims 1 to 8, characterized in that: The following steps are involved: Insert two metal rods into the soil to make the device level and make the highest position of the ground protrusion contact with the probe unit; Tighten the pulley screw to straighten the resistance wire so that all the probe units are at the same horizontal position and parallel and equidistant to the short plastic plate at the top. The tops of the two metal rods are connected to the power supply device and the data collector through wires. The voltage value V1 at both ends of the resistance wire is measured by the data collector at this time. After that, loosen the pulley screw to loosen the resistance wire, press the probe unit vertically downward until the rubber support at the bottom of each probe unit is close to the soil surface, tighten the pulley screw so that the resistance wire can be consistent with the contour connection shape of the top of the probe unit, and measure the voltage value V2 at both ends of the resistance wire at this time by the data collector. According to Ohm's law Apply the same current I and calculate the resistance of the resistance wire R1 and R2; According to the law of resistance Where ρ is the resistivity, S is the cross-sectional area, and the lengths of the resistance wire L1 and L2 before and after the measurement are calculated; The surface roughness Cr of the biological crust soil is determined by the relationship equation Cr = (1-L1 / L2) × 100 between the change in resistance wire length and soil roughness.

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