Slope ecological restoration layer soil multi-mode intelligent irrigation water migration testing device and method

Abstract

The invention relates to a slope ecological restoration layer soil multi-mode intelligent irrigation moisture migration testing device and method. The method comprises the following steps: introducing characteristic value parameters of a wetting body, and testing and monitoring the moisture content and nutrients of the soil body; and a control variable method is combined to obtain a wetting front migration rule under the conditions of different gradients, different irrigation flows and different irrigation amounts and a soil moisture and nutrient distribution rule in a wetting body under the conditions of different gradients and different dripper flows. The system and the method have the beneficial effects that the problems of poor slope adaptability, insufficient monitoring precision and the like in the traditional technology are solved, and accurate testing and monitoring of a wetting front migration rule of a multi-mode irrigation ecological restoration layer with different gradients, irrigation amounts and irrigation flows and a soil moisture and nutrient distribution rule in a wetting body are realized; scientific guidance and data support can be provided for slope ecological restoration soil layer irrigation system design and optimization, ecological restoration layer material ratio optimization and maintenance irrigation work.

Description

Technical Field

[0001] This invention relates to the field of indoor drip irrigation testing technology for soil in slope ecological restoration layers, specifically to a multimodal intelligent irrigation water transport testing device and method for soil in slope ecological restoration layers. Background Technology

[0002] Currently, with the rapid development of infrastructure construction, the demand for ecological restoration of large-scale engineering spoil heaps and slopes is becoming increasingly urgent. Artificial soil reconstruction and vegetation restoration are core means to address ecological damage and soil erosion at spoil heaps, and irrigation technology in the later stages of maintenance has become a key factor restricting the effectiveness of ecological restoration. Drip irrigation technology, due to its water-saving, high-efficiency, and precise controllability characteristics, has become the preferred solution for slope ecological restoration irrigation; however, the application of existing technologies under soil reconstruction conditions with steep slopes (>10°) still faces significant technical bottlenecks.

[0003] The main drawbacks of the existing technology are as follows:

[0004] Insufficient slope adaptability: Traditional drip irrigation technology research is mostly based on natural soil conditions in open fields or gentle slopes (slope ≤ 10°). There is a lack of systematic research on the water transport patterns in reconstructed soils of large slopes (such as 15°-45°), which cannot accurately reveal the influence mechanism of slope on the expansion of wetting fronts and water distribution.

[0005] Limitations in monitoring accuracy and dimensionality: Existing testing methods mostly rely on single-point sampling or two-dimensional planar monitoring, lacking real-time high-precision monitoring of the dynamic distribution of water and nutrients in three-dimensional wet bodies. It is difficult to obtain characteristic parameters of wet frontal movement (such as R+, R-, Rmax, Hmax, etc.) in the downslope, upslope, and cross slope directions, as well as spatiotemporal variation data of soil moisture content and ion concentration.

[0006] The lack of multimodal irrigation systems: Traditional devices only support a single irrigation mode (such as drip irrigation) and cannot be compatible with multimodal switching such as drip irrigation, micro-sprinkler irrigation, and seepage irrigation. It is difficult to simulate the actual irrigation needs in complex slope environments, resulting in a disconnect between test results and engineering application scenarios. Summary of the Invention

[0007] The purpose of this invention is to fill the gap in current research on the applicability of soil irrigation for ecological restoration layers on steep slopes, and to address the problem of low accuracy in indoor testing in this research. It provides a multimodal intelligent irrigation water transport testing device and method for ecological restoration layers. Specifically, for spoil heap slopes under ecological restoration and reconstruction soil conditions with steep slopes, indoor soil box experiments were conducted to achieve visualized monitoring of the wetting front transport patterns and the distribution patterns of soil moisture and nutrients within the wetting layer under multimodal irrigation of ecological restoration layers with different slopes, irrigation volumes, and dripper flow rates.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A multimodal intelligent irrigation water transport testing device for soil in slope ecological restoration layers includes:

[0010] Slope simulation system: including a visible soil box (1) and a hydraulic tipper truck (2). The visible soil box (1) is a cuboid structure made of plexiglass. The visible soil box (1) is fixed on the hydraulic tipper truck (2) with an adjustable angle. The bottom of the visible soil box (1) is filled with waste, slope soil or slope rock blocks with a height of not less than 20cm to simulate the slope surface.

[0011] Multimodal intelligent irrigation system: A multimodal irrigation system integrating drip irrigation, micro-sprinkler irrigation and seepage irrigation modes, including solenoid valve, peristaltic pump (3), water tank (4) and dripper (7). The peristaltic pump (3) is installed on the outer shell of the water tank (4). The peristaltic pump (3) is connected to the inside of the water tank (4) and the dripper (7) through pipes respectively. The dripper is installed at the designed position of the visible soil box (1). The solenoid valve is installed on the connecting pipe between the dripper (7) and the peristaltic pump (3). The solenoid valve controls the flow rate to be 0.1-5L / h.

[0012] High-precision sensor array: including a moisture sensor (8), an ion concentration probe (9), a water quality analyzer (10), and a data acquisition terminal (11). The moisture sensor (8) and the ion concentration probe (9) are arranged in a 10cm×10cm grid at different depths of the repair layer. The water quality analyzer (10) is installed on the water tank (4). The moisture sensor (8), the ion concentration probe (9), and the water quality analyzer (11) are all electrically connected to the data acquisition terminal (11).

[0013] A multimodal intelligent irrigation water transport testing method for soil in slope ecological restoration layers includes the following steps:

[0014] Prepare the ecological restoration layer soil: Take waste residue, planting soil, modified glutinous rice-based ecological restoration material and attapulgite slow-release fertilizer, mix them evenly according to the actual project ratio to form the ecological restoration layer soil, and then air dry it for later use.

[0015] Slope adjustment simulation system: A rectangular visible soil box made of plexiglass is fixed on an adjustable-angle hydraulic dump truck. Waste, slope soil or slope rock blocks with a height of not less than 20cm are filled at the bottom of the visible soil box to simulate the slope surface.

[0016] Set up an intelligent irrigation system: a multimodal irrigation system integrating drip irrigation, micro-sprinkler irrigation and seepage irrigation, with the flow rate controlled by solenoid valves at 0.1-5L / h, and drippers connected to peristaltic pumps placed at the designed positions in the visible soil tank;

[0017] Simulated ecological restoration layer: Fill the visible soil box with test soil. First, fill the bottom of the visible soil box with waste, slope soil or slope rock blocks with a height of not less than 20cm to simulate the slope surface. Then fill the 20cm thick ecological restoration layer soil. When filling, layer and compact every 5cm. After filling, cover the surface of the ecological restoration layer soil with an plexiglass cover and let it stand for 24 hours.

[0018] A high-precision sensor array is installed in the soil of the ecological restoration layer: moisture sensors and ion concentration probes are arranged in a 10cm×10cm grid at different depths of the restoration layer, and a water quality analyzer is installed on the water tank. The moisture sensors, ion concentration probes and water quality analyzer are electrically connected to the data acquisition terminal.

[0019] Water from the tank is delivered to the drippers via a peristaltic pump for drip irrigation. Once irrigation begins, a vertical wetting front is drawn on the plexiglass plate on the front of the soil tank, and a horizontal wetting front is drawn on the plexiglass cover above the ecological restoration layer, following a time interval of dense wetting followed by sparse wetting, controlled by the peristaltic pump and solenoid valve. Points are taken on both the vertical and horizontal wetting fronts, and wetting lines are drawn based on the coordinates of these points. The wetting distance R of the ecological restoration layer along the slope is then measured using these wetting lines. + 1. Wetting distance R of the ecological restoration layer in the reverse slope direction; 2. Wetting distance R of the ecological restoration layer in the transverse slope direction; 3. Maximum wetting width R in the transverse slope direction. max Infiltration depth H at the dripper, maximum infiltration depth H max Maximum wetting width offset distance L in the transverse slope direction R Maximum infiltration depth offset distance L H Eight characteristic parameters of the wetting front were obtained. Throughout the drip irrigation process, the moisture content, nutrients, electrical conductivity, and pH value of the soil sample were measured in real time by setting up a high-precision sensor array.

[0020] By adjusting the slope, dripper flow rate, and irrigation volume using the controlled variable method, the movement pattern of the moist front under different variable conditions was obtained based on the measured characteristic parameters of the moist front movement. The distribution pattern of soil moisture and nutrients under different variable conditions was obtained based on the measured soil sample moisture content and nutrients.

[0021] Furthermore, when drawing the wetting line, take the drip tip position as the origin on the glass panel, and take points on the contour of the wetting front in 18 directions in a clockwise direction at 15° intervals. Use a steel ruler to measure the horizontal and vertical coordinates of each point, and use AutoCAD software to draw the wetting line based on the horizontal and vertical coordinates of each point.

[0022] Furthermore, throughout the drip irrigation process, a high-precision sensor array is set up to measure the soil moisture content, nutrients, electrical conductivity, and pH value in real time. Based on the location of each sensor and its moisture content, the contour boundary of the wetting front is calculated and determined.

[0023] Furthermore, before mixing the ecological restoration layer soil, take the waste residue, air-dry it, and then pass it through a 20mm sieve for later use. Take the planting soil, air-dry it, crush it, and then pass it through a 2mm sieve for later use. The slope surface rock and soil are also prepared for later use.

[0024] Furthermore, the modified glutinous rice-based ecological restoration material is formed by combining modified glutinous rice base material with soil particles and waste residue after encapsulation and adsorption to form aggregates, thereby enhancing the water retention and erosion resistance of the soil. The modified glutinous rice base material includes glutinous rice flour, plant fiber, modifier, and attapulgite slow-release fertilizer.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. This invention addresses the slope of a spoil heap under conditions of steeply reconstituted soil. An indoor soil test was conducted to monitor irrigation water transport. The process involved mixing reconstituted soil, setting up the test equipment, filling the test soil, conducting drip irrigation tests, and analyzing the results. This was achieved by introducing R... + 、R-、R、R max H, H max By testing and monitoring isotropic characteristic parameters and soil moisture content, nutrients, and water quality, and combining the controlled variable method, the effects of three factors—slope, dripper flow rate, and irrigation volume—on the movement of the moist front and the distribution of soil moisture and nutrients within the moist body in slope drip irrigation were studied. This approach addresses the problems of poor slope adaptability and insufficient monitoring accuracy in traditional techniques. It can provide scientific guidance and data support for the design and optimization of irrigation systems for slope ecological restoration layers, the optimization of material ratios for ecological restoration layers, and maintenance irrigation work, effectively improving ecological restoration results and reducing maintenance and management costs.

[0027] 2. This invention introduces visual monitoring and intelligent sensor arrays to systematically study the influence of multiple variables such as slope, irrigation volume, and irrigation flow on water transport, providing key data support for the design of irrigation systems for slope ecological restoration layers, optimization of material ratios, and formulation of maintenance strategies. Through the control variable method and real-time monitoring of multiple parameters, it fills the research gap in the field of drip irrigation for steep slopes, significantly improving the engineering adaptability and ecological restoration effectiveness of irrigation systems. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the multimodal intelligent irrigation water transport testing device for slope ecological restoration layer soil according to the present invention;

[0029] Figure 2 This is a schematic diagram showing the layout of the moisture sensor and ion concentration sensor in this invention;

[0030] Figure 3 This is a schematic diagram illustrating the changes in the characteristic parameters of the moist front migration under different slope conditions in this invention;

[0031] Figure 4 This is a schematic diagram illustrating the variation process of various wetting front transport characteristic parameters under different dripper flow rates in this invention;

[0032] Figure 5 This is a schematic diagram of the moisture content distribution along the slope direction and cross slope direction at the drip head under different slope conditions in this invention;

[0033] Figure 6 This is a schematic diagram comparing the moisture content of various monitoring points under different slope conditions in this invention;

[0034] Figure 7 This is a schematic diagram of the moisture content distribution along the slope and cross slope of the dripper under different dripper flow rates in this invention.

[0035] Figure 8 This is a schematic diagram comparing the moisture content at various monitoring points under different dripper flow rates in this invention.

[0036] In the diagram: 1. Soil tank; 2. Hydraulic dump truck; 3. Peristaltic pump; 4. Water tank; 5. Soil in the ecological restoration layer; 6. Slope surface; 7. Dripping nozzle; 8. Moisture sensor; 9. Ion concentration probe; 10. Water quality analyzer; 11. Data acquisition terminal. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0038] like Figure 1 , Figure 2 As shown, a multimodal intelligent irrigation water transport testing device for soil in an ecological restoration layer of a slope includes a soil tank 1, a hydraulic tipper truck 2, a peristaltic pump 3, a water tank 4, drippers 7, a moisture sensor 8, an ion concentration probe 9, a water quality analyzer 10, and a data acquisition terminal 11. The soil tank 1 is a cuboid made of plexiglass and is fixed to the hydraulic tipper truck 2. The soil tank 1 is used to fill the ecological restoration layer soil 5, thereby simulating the slope surface 6. The drippers 7 are arranged above the ecological restoration layer soil 5, enabling drip irrigation. Replacing the drippers 7 with seepage irrigation heads or micro-sprinkler irrigation heads allows for seepage irrigation or micro-sprinkler irrigation. The moisture sensor 8 and the ion concentration probe 9 are arranged inside the ecological restoration layer soil 5. The water quality analyzer 10 is installed on the water tank 4. The moisture sensor 8, ion concentration probe 9, and water quality analyzer 10 are all electrically connected to the data acquisition terminal 11.

[0039] Moisture sensor 8 uses a time-domain reflectometer (TDR) with an accuracy of ±2%; ion concentration probe 9 is used to monitor nutrient (N / P / K) and salt migration; water quality analyzer 10 is used to monitor parameters such as pH, conductivity, and turbidity of the water in water tank 4 online; data acquisition terminal 11 supports 5G transmission and real-time synchronization to the cloud platform, using a maximum frequency of 1Hz. Data monitored by moisture sensor 8, ion concentration probe 9, and water quality analyzer 10 is transmitted to data acquisition terminal 11.

[0040] When conducting tests using the aforementioned multimodal intelligent irrigation water transport testing device for slope ecological restoration layer soil, the specific steps include the following S1-S4:

[0041] S1. Prepare the ecological restoration layer soil: Take waste residue, planting soil, modified glutinous rice-based ecological restoration material and attapulgite slow-release fertilizer, mix them evenly according to the actual project ratio to form the ecological restoration layer soil, and then air dry it for later use.

[0042] Before mixing the ecological restoration layer soil, take the waste residue, air dry it, and then pass it through a 20mm sieve for later use. Take the planting soil, air dry it, crush it, and then pass it through a 2mm sieve for later use. The slope surface soil is also prepared for later use. The modified glutinous rice-based ecological restoration material is formed by combining modified glutinous rice base material with soil particles and waste residue after encapsulation and adsorption to form aggregates, which enhances the water retention and erosion resistance of the soil. The modified glutinous rice base material includes glutinous rice flour, plant fiber, modifier, and attapulgite slow-release fertilizer.

[0043] S2. Adjustable slope simulation system: A rectangular visible soil box 1 made of plexiglass is fixed on an adjustable-angle hydraulic dump truck 2. Waste, slope soil or slope rock blocks with a height of not less than 20cm are filled at the bottom of the visible soil box 1 to simulate the slope surface.

[0044] S3. Set up an intelligent irrigation system: a multimodal irrigation system integrating drip irrigation, micro-sprinkler irrigation and seepage irrigation, with the flow rate controlled by a solenoid valve at 0.1-5L / h, and the dripper 7 connected to the peristaltic pump 3 arranged at the designed position of the visible soil box 1;

[0045] S4. Simulated Ecological Restoration Layer: Test soil was filled into the visible soil box 1. First, waste, slope soil, or slope rock blocks with a height of not less than 20cm were filled at the bottom of the visible soil box 1 to simulate the slope surface 6. Then, a 20cm thick ecological restoration layer of soil was filled in, with layers compacted every 5cm. After filling, an plexiglass cover was placed on the surface of the ecological restoration layer soil and allowed to stand for 24 hours. The moisture characteristics of the test soil after filling are shown in Table 1 below.

[0046] Table 1. Moisture characteristics of the test soil

[0047] <![CDATA[Unit weight / g·cm -3 > Initial moisture content / % Field water holding capacity / % Saturated moisture content / % Discard slag 1.8 1.06 12.36 16.76 Reconstructed soil 1.6 2.19 16.50 26.11

[0048] S5. Install a high-precision sensor array in the soil of the ecological restoration layer: Arrange the moisture sensor 8 and ion concentration probe 9 in a 10cm×10cm grid at different depths of the restoration layer, install the water quality analyzer 10 on the water tank 4, and electrically connect the moisture sensor 8, ion concentration probe 9 and water quality analyzer 11 to the data acquisition terminal 11.

[0049] S6. Water from tank 4 is pumped to dripper 7 via peristaltic pump 3 for drip irrigation. After drip irrigation begins, according to the peristaltic pump 3 and solenoid valve control, a vertical wetting front profile is drawn on the plexiglass plate on the front of the soil tank, and a horizontal wetting front profile is drawn on the plexiglass cover plate above the ecological restoration layer soil, following a time interval of dense wetting followed by sparse wetting. Points are taken on the vertical and horizontal wetting front profiles with the dripper as the origin, and wetting lines are drawn based on the horizontal and vertical coordinates of the points. The wetting distance R of the ecological restoration layer along the slope is measured based on the wetting lines. + 1. Wetting distance R of the ecological restoration layer in the reverse slope direction; 2. Wetting distance R of the ecological restoration layer in the transverse slope direction; 3. Maximum wetting width R in the transverse slope direction. max Infiltration depth H at the dripper, maximum infiltration depth H max Maximum wetting width offset distance L in the transverse slope direction R Maximum infiltration depth offset distance L H Eight characteristic parameters of the wetting front were obtained. Throughout the drip irrigation process, a high-precision sensor array was set up to monitor the soil in two vertical profiles along the slope and across the slope where the dripper is located in real time. Parameters such as soil moisture content, nutrients, electrical conductivity, and pH value were measured. Based on the location of each sensor and its moisture content, the contour boundary of the wetting front was calculated and determined.

[0050] More specifically, when drawing the wetting line, take the dripper position as the origin, and take points on the contour of the wetting front in 18 directions in a clockwise direction at 15° intervals. Use a steel ruler to measure the horizontal and vertical coordinates of each point, and use AutoCAD software to draw the wetting line based on the horizontal and vertical coordinates of each point.

[0051] S5. Using the controlled variable method, the slope is adjusted by a hydraulic tipper truck, and the dripper flow and irrigation volume are adjusted by a peristaltic pump. Based on the measured wet front transport characteristic parameters, the wet front transport law under different variable conditions is obtained. Based on the measured soil sample moisture content and nutrients, the soil moisture and nutrient distribution law under different variable conditions is obtained.

[0052] Based on the above method, this application conducted a field drip irrigation test. The soil box 1 had dimensions of 100cm in length, 60cm in width, and 50cm in height. Waste material was taken from the Maojiagou spoil heap of the Sichuan-Tibet Railway, mainly from the Kangding No. 1 and No. 2 tunnels, primarily composed of diorite and metamorphic quartz sandstone. The planting soil was taken from Chengdu loess. For ease of observation, half of the wetted body was used as the research object in the field test. The test included three slopes (15°, 30°, 45°), three dripper flow rates (1L / h, 1.5L / h, 2L / h), and three irrigation volumes (3L, 5L, 7L). Because half of the wetted body was used as the research object, the dripper flow rate and irrigation volume were both half of the above values ​​in the specific test, i.e., dripper flow rates were 0.5L / h, 0.75L / h, and 1.0L / h, and irrigation volumes were 1.5L, 2.5L, and 3.5L, respectively.

[0053] The slope directly affects the migration process of the wetting front. In field experiments, the slope was simulated by adjusting the tilt angle of the soil box using a hydraulic dump truck. An irrigation combination of 0.75 L / h dripper flow rate and 2.5 L irrigation volume was selected to study the migration patterns of the wetting front under slope conditions of 15°, 30°, and 45°. The changes in the characteristic parameters of the wetting front migration under different slope conditions were obtained as follows: Figure 3 As shown.

[0054] Depend on Figure 3 (a) Figure 3 (b) It can be seen that at the beginning of irrigation, the migration distance of the moistening front in different directions of the slope is not significantly different. As irrigation progresses, the diffusion rate of water in different directions varies due to the slope gradient, causing the difference in the migration distance of the moistening front in different directions to gradually increase. Furthermore, under the above three slope conditions, the migration distance of the moistening front in different directions of the slope is R at the same irrigation time. + >R max >R>R-. The movement of the moistening front in the same direction is also significantly affected by slope; the steeper the slope, the greater the distance the moistening front moves downhill. At the end of irrigation, R under the above three slope conditions... + The values ​​were 271mm, 316mm, and 359mm, respectively. The steeper the slope, the shorter the distance the wetting front travels in both the transverse and reverse slope directions. At the end of irrigation, the R values ​​under the above three slope conditions were... max The diameters are 260mm, 247mm, and 229mm respectively; the radius (R) is 253mm, 235mm, and 201mm respectively; and the diameter (R-) is 185mm, 174mm, and 149mm respectively. From Figure 3 (c) It can be seen that the infiltration depth increases continuously with irrigation, but unlike drip irrigation on horizontal surfaces, the maximum infiltration depth does not occur at the dripper due to the slope, and H and H maxThe results also varied with different slope angles. At the end of irrigation, the values ​​of H under the three slope conditions were 196 mm, 203 mm, and 238 mm, respectively. max They are 207mm, 219mm, and 254mm respectively, H and H max The slope is greatest at 45°, followed by 30°, and smallest at 15°. R is affected by the slope. max With H max It did not appear in the cross slope direction at the dripper or directly below the dripper, but rather shifted, as shown below. Figure 3 As shown in (d), offset along the slope is considered positive, and offset against the slope is considered negative. L R The water level fluctuated significantly in the initial stage of irrigation, and then gradually stabilized. max It clearly shifts downhill, and the greater the slope, the greater the shift distance. H It also fluctuates initially and then tends to stabilize. However, H varies under different slope conditions. max The water shifts in different directions. At 15° and 30°, it shifts downhill, while at 45° it shifts uphill. This difference may be due to the fact that on steeper slopes, although water mainly moves downhill, the increase in infiltration depth in the downhill area is usually less than the decrease in ground elevation, resulting in a relatively smaller actual infiltration depth downhill. Meanwhile, water infiltration in the uphill area includes not only vertical infiltration but also upward wetting expansion, which causes the maximum infiltration depth to occur above the dripper slope.

[0055] The dripper flow rate is an important indicator of drip irrigation parameters. In field trials, a combination of a 15° slope and an irrigation volume of 2.5L was selected to study the wetting front migration under dripper flow rates of 0.5L / h, 0.75L / h, and 1.0L / h. The changes in various wetting front migration characteristic parameters under different dripper flow rates were obtained as follows: Figure 4 As shown.

[0056] In the initial stage of irrigation, the diffusion distance of water in different directions is similar, and due to the low soil moisture content and large soil suction gradient, the water diffusion rate is also fast. As irrigation time increases, the soil suction gradient gradually decreases, and although water still diffuses in different directions, its diffusion rate slows down. Figure 5 (a) Figure 5 As can be seen in (b), due to the influence of slope, the migration distance of the wetting front in different directions on the slope under the above three dripper flow conditions all show R at the same irrigation time. + >R max >R>R-. The higher the dripper flow rate, the greater the irrigation volume within the same irrigation time, and the larger the slope wetting radius in the same direction. Specifically, the higher the dripper flow rate, the greater the distance the wetting front travels downhill. At the end of irrigation, R under the above three dripper flow rate conditions... +The values ​​were 265mm, 271mm, and 324mm, respectively. The higher the dripper flow rate, the shorter the wetting front transport distance in both the cross and reverse slope directions. At the end of irrigation, R under the above three dripper flow rate conditions... max The diameters are 270mm, 260mm, and 233mm respectively; the radius (R) is 270mm, 253mm, and 260mm respectively; and the radius (R-) is 200mm, 185mm, and 164mm respectively. From Figure 5 (c) It can be seen that the infiltration depth under different dripper flow rates all show an increasing trend with irrigation time, and the rate of increase gradually slows down. The larger the dripper flow rate, the greater the irrigation volume in the same irrigation time. H and H max The larger the flow rate, the higher the H values ​​under the three dripper flow conditions at the end of irrigation are: 207 mm, 196 mm, and 186 mm, respectively. max The values ​​are 213mm, 207mm, and 191mm respectively, indicating that the larger the dripper flow rate, the shorter the irrigation time for the same irrigation volume. H and H max The smaller the value. R is affected by slope, and varies under different dripper flow rates. max With H max They all shifted, such as Figure 5 As shown in (d), under a slope of 15°, R max With H max All appeared at the drip head along the slope direction, L R With L H The overall trend is increasing, but the growth rate gradually slows down. At the end of irrigation, for the same amount of irrigation, the larger the dripper flow rate (L)... R With L H The larger.

[0057] The irrigation volume is determined by both the dripper flow rate and the irrigation time. When the dripper flow rate is constant, the irrigation time directly reflects the irrigation volume. Figure 3 , Figure 4 It can be seen that when the slope and the dripper flow rate are the same, R + 、R-、R、R max H, H max All showed an increasing trend with irrigation time (irrigation volume). Understanding the relationship between the characteristic values ​​of the wetted body and irrigation time during infiltration under different slope gradients and dripper flow rates is crucial for determining irrigation parameters and field layout methods for slope drip irrigation. R... + 、R-、R、R max H, H max Experimental data varying with irrigation time t were fitted, and the fitting revealed a significant power function relationship between the migration distance of the wetting front in each direction and irrigation time, with a coefficient of determination (R²) of 1 / 2. 2 All values ​​are greater than 0.95. The specific fitting equation parameters are shown in Table 2 below.

[0058] Table 2. Fitting equation parameters for the migration of moist fronts

[0059]

[0060]

[0061] As shown in Table 2, with changes in slope and dripper flow rate, the power function coefficient 'a' changes significantly, while the power exponent 'b' changes less, and all power exponents 'b' are less than 1. This indicates that as irrigation time progresses, the migration distance of the wetting front in each direction will tend to stabilize.

[0062] To investigate the effect of slope on soil moisture distribution within a moist soil, a field experiment was conducted using an irrigation volume of 2.5 L and a dripper flow rate of 0.75 L / h. The study examined the moisture content distribution along the slope and across the cross slope at the dripper location when irrigation ceased, under different slope conditions. The specific moisture content distribution is shown in the figure below. Figure 5 As shown.

[0063] Depend on Figure 5 It is evident that slope significantly affects the distribution of moisture content within the moist body. Moisture primarily migrates downhill, with the highest moisture content near the drippers, decreasing towards the edge of the moist body. The steeper the slope, the denser the isopleths in the profile, indicating a more uneven distribution of soil moisture. Furthermore, as the slope increases, the curvature of the moisture content isopleths decreases, suggesting that more moisture migrates downhill and less infiltrates along the direction of gravity.

[0064] Depend on Figure 5 (a) Figure 5 (b) Figure 5 (c) It can be seen that the soil moisture content along the slope profile in the direction of gravity decreases with increasing depth. Figure 4 (c) Taking this as an example, the soil moisture content at 5cm, 10cm, 15cm, and 20cm vertically from the dripper was 17.7%, 16.5%, 15.2%, and 10.1%, respectively. At the same depth, at points equidistant from the dripper's vertical line in both the downslope and upslope directions, the moisture content at the downslope point was significantly higher than that in the upslope point. Furthermore, regardless of the slope direction, the soil moisture content decreased with increasing distance from the dripper's vertical line. Figure 5 (b) Taking this as an example, the moisture contents at 5cm, 10cm, and 15cm along the slope in the 5cm depth layer are 17.6%, 17.4%, and 16.4%, respectively, while the moisture contents at 5cm, 10cm, and 15cm against the slope are 14.2%, 13.5%, and 12.2%, respectively. Figure 5 (d) Figure 5 (e) Figure 5 (f) It can be seen that the soil moisture content in the transverse profile along the direction of gravity decreases with increasing depth. At the same depth, the moisture content is highest below the dripper, and the moisture content decreases with increasing horizontal distance from the dripper. Figure 5(d) For example, the moisture content at horizontal distances of 0cm, 5cm, 10cm, 15cm and 20cm from the dripper in the 5cm depth layer is 18.9%, 17.3%, 16.0%, 15.3% and 13.7%, respectively. The greater the slope, the less water is transported along the transverse slope, and the smaller the average moisture content in the same humid area in the transverse profile.

[0065] Under slope conditions of 15°, 30°, and 45°, the moisture content at monitoring points located at different depths and at different distances from the vertical line of the dripper along the slope and cross slope at the dripper is as follows: Figure 6 As shown. By Figure 6 (a) It can be seen that in the slope profile, the greater the slope, the smaller the soil moisture content at the same depth layer and the same distance from the dripper vertical line in the reverse slope direction. Taking the soil at a depth of 10cm and 10cm from the dripper vertical line as an example, the soil moisture content at the end of irrigation is 14.3%, 12.9%, and 11.4%, respectively. Along the slope, the moisture content at the same monitoring point in the surface layer showed the highest value at a slope of 45°, followed by 30°, and the lowest at 15°. However, changes occurred at a depth of 5cm. At 20cm from the dripper's vertical line, the moisture content at different slope angles showed the same relationship as at the surface layer. At 15cm from the dripper's vertical line, the moisture content under the three slope angles was 16.2%, 16.4%, and 16.0%, respectively. At 0cm, 5cm, and 10cm from the dripper's vertical line, the moisture content showed the highest value at 15°, followed by 30°, and the lowest at 45°. The same relationship was observed at the same monitoring point in the 10cm and 15cm depth layers. This indicates that at steeper slopes, more water migrates along the slope direction to the surface layer, while vertical infiltration is relatively weaker. Figure 6 (b) It can be seen that at different depths in the transverse profile, the moisture content at points at the same horizontal distance from the dripper decreases with increasing slope. This is because a gentler slope is more conducive to the diffusion of water across the transverse slope. The above pattern indicates that the greater the slope, the more significantly the slope affects the transport of drip irrigation water, and the more uneven the moisture content distribution within the wetting body.

[0066] To investigate the effect of dripper flow rate on soil moisture distribution within the moist soil, a field experiment was conducted using a slope of 15° and an irrigation volume of 2.5 L. The study examined the soil moisture content distribution along the slope and across the cross slope at the end of irrigation under different dripper flow rates. The specific distribution is shown in the figure below. Figure 7 As shown.

[0067] Under the same slope conditions, the dripper flow rate has a significant impact on the profile moisture content distribution. Figure 7 (a) Figure 7 (b) Figure 7(c) It is evident that as the dripper flow rate increases, the area of ​​high surface water content (≥20%) below the dripper expands towards the downslope. This is because the increased dripper flow rate prevents water from infiltrating quickly enough, causing some water to form surface runoff and migrate downslope, completing infiltration at a certain distance from the dripper. Furthermore, the larger the dripper flow rate, the denser the isopleths of water content in the profile, indicating a more uneven water distribution. This is because, under the same irrigation volume, a smaller dripper flow rate results in a longer infiltration time, which is more conducive to achieving water content equilibrium at various points within the wetting body. Figure 7 (d) Figure 7 (e) Figure 7 (f) It can be seen that in the transverse profile of the dripper, the soil moisture content changes from large to small at positions from far to near the dripper in the same direction. Moreover, the larger the dripper flow rate, the lower the average moisture content in the same humid area. This indicates that a smaller dripper flow rate is more conducive to the diffusion of water in the transverse slope direction.

[0068] Under dripper flow rates of 1.0 L / h, 0.75 L / h, and 0.5 L / h, the moisture content at monitoring points located at different depths and at different distances from the vertical line of the dripper along the slope and cross slope at the dripper is as follows: Figure 8 As shown. By Figure 8 (a) It can be seen that, along the slope profile, the soil moisture content at the same location on the reverse slope direction decreases with increasing dripper flow rate; on the downslope direction, the soil moisture content at the same location in the surface layer (0cm) and the 5cm depth layer shows the highest at 1.0L / h, followed by 0.75L / h, and the lowest at 0.5L / h. However, this phenomenon changes at the 10cm depth layer. Specifically, at a distance of 20cm from the dripper's vertical line, the soil moisture content under the three dripper flow rates is 10.9%, 12.1%, and 14.4%, respectively. The relationship between soil moisture content at 0cm, 5cm, and 10cm from the dripper's vertical line shows the highest at 0.5L / h, followed by 0.75L / h, and the lowest at 1.0L / h. The same relationship is observed at the 15cm depth layer. Figure 8 (b) It can be seen that, at different depths in the transverse profile, the soil moisture content at the same horizontal distance from the dripper is highest at a dripper flow rate of 0.5 L / h, followed by 0.75 L / h, and lowest at 1.0 L / h. This indicates that a higher dripper flow rate is more conducive to the transport of water downhill, but less conducive to the transport of water uphill, across slope, and in the direction of gravity.

[0069] The above experimental results show that, when the irrigation volume and dripper flow rate are the same, the greater the slope, the greater the distance of the wetting front along the slope, the greater the infiltration depth below the dripper, and the greater the maximum infiltration depth, while the distance of the wetting front along the reverse slope and the transverse slope of the dripper, and the smaller the maximum distance of the wetting front along the transverse slope. When the slope and irrigation volume are fixed, the greater the dripper flow rate, the greater the distance of the wetting front along the slope, while the distance of the wetting front along the reverse slope, the transverse slope of the dripper, and the vertical slope is smaller, and the maximum distance of the wetting front along the transverse slope and the vertical slope also decreases accordingly. The migration distance of the wetting front in all directions and the vertical infiltration depth both exhibit a significant power function relationship with irrigation time (irrigation volume), and the migration rate of the wetting front in all directions decreases with increasing irrigation time. At the end of irrigation, the soil moisture content within the wetting body decreases in all directions with increasing distance from the dripper. Due to the influence of slope, at the same depth layer and at the same distance from the dripper, the moisture content at the point along the slope is higher than that at the point against the slope. At the end of irrigation, at the same monitoring point in the cross-slope and up-slope profiles, the moisture content decreases with increasing slope and dripper flow rate. The response of monitoring points at different depth layers in the down-slope profile to slope and dripper flow rate varies; the greater the slope and dripper flow rate, the higher the average moisture content of the 0cm and 5cm layers, and the smaller the slope and dripper flow rate, the higher the average moisture content of the 10cm and 15cm layers.

[0070] This invention addresses the slope of a spoil heap under conditions of steeply reconstructed soil. It employs an indoor soil test chamber to simulate irrigation water transport, and introduces R... + 、R-、R、R max H, H max This study investigated the effects of slope, dripper flow rate, and irrigation volume on the movement of the wetting front and the distribution of soil moisture within the wetting body in slope drip irrigation by sampling and measuring characteristic parameters of the wetting body and soil moisture content. This research provides scientific guidance for the design and practical engineering application of slope drip irrigation systems. The results showed a significant power-law relationship between the characteristic values ​​of the wetting body and irrigation time, and that the movement distance of the wetting front increases with irrigation time while the movement speed decreases. Therefore, in practical engineering applications, the irrigation time should not be too long to avoid water waste due to low water diffusion efficiency later on. Intermittent irrigation methods can be used to improve irrigation efficiency. In slope drip irrigation, when the dripper flow rate exceeds the infiltration rate, surface runoff is formed. Unlike water accumulation on horizontal surfaces, surface runoff moves downhill and infiltrates below the dripper. This makes a larger dripper flow rate more beneficial for R... + The diffusion of R-, R, and R is unfavorable. max H, H maxTherefore, in slope drip irrigation, using a small dripper flow rate can reduce the degree of displacement of the moist body down the slope, making the water distribution in all directions more uniform. In addition, the problem of insufficient soil moisture coverage in the transverse slope direction can be compensated by appropriately reducing the dripper spacing.

[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multimodal intelligent irrigation water transport testing device for soil in slope ecological restoration layers, characterized in that, include: Slope simulation system: including a visible soil box (1) and a hydraulic tipper truck (2). The visible soil box (1) is a cuboid structure made of plexiglass. The visible soil box (1) is fixed on the hydraulic tipper truck (2) with an adjustable angle. The bottom of the visible soil box (1) is filled with waste, slope soil or slope rock blocks with a height of not less than 20cm to simulate the slope surface. Multimodal intelligent irrigation system: A multimodal irrigation system integrating drip irrigation, micro-sprinkler irrigation and seepage irrigation modes, including solenoid valve, peristaltic pump (3), water tank (4) and dripper (7). The peristaltic pump (3) is installed on the outer shell of the water tank (4). The peristaltic pump (3) is connected to the inside of the water tank (4) and the dripper (7) through pipes respectively. The dripper is installed at the designed position of the visible soil box (1). The solenoid valve is installed on the connecting pipe between the dripper (7) and the peristaltic pump (3). The solenoid valve controls the flow rate to be 0.1-5L / h. High-precision sensor array: including a moisture sensor (8), an ion concentration probe (9), a water quality analyzer (10), and a data acquisition terminal (11). The moisture sensor (8) and the ion concentration probe (9) are arranged in a 10cm×10cm grid at different depths of the repair layer. The water quality analyzer (10) is installed on the water tank (4). The moisture sensor (8), the ion concentration probe (9), and the water quality analyzer (11) are all electrically connected to the data acquisition terminal (11).

2. A multimodal intelligent irrigation water transport testing method for soil in slope ecological restoration layers, characterized in that, Includes the following steps: Prepare the ecological restoration layer soil: Take waste residue, planting soil, modified glutinous rice-based ecological restoration material and attapulgite slow-release fertilizer, mix them evenly according to the actual project ratio to form the ecological restoration layer soil, and then air dry it for later use. Adjustable slope simulation system: A rectangular visible soil box (1) made of plexiglass is fixed on an adjustable-angle hydraulic tipper truck (2). Waste, slope soil or slope rock blocks with a height of not less than 20cm are filled at the bottom of the visible soil box (1) to simulate the slope surface. Set up an intelligent irrigation system: a multimodal irrigation system integrating drip irrigation, micro-sprinkler irrigation and seepage irrigation, with the flow rate controlled by a solenoid valve at 0.1-5L / h, and the dripper (7) connected to the peristaltic pump (3) arranged at the designed position of the visible soil box (1); Simulated ecological restoration layer: Fill the test soil into the visible soil box (1). First, fill the bottom of the visible soil box (1) with waste, slope soil or slope rock blocks with a height of not less than 20cm to simulate the slope surface (6). Then fill the ecological restoration layer soil with a thickness of 20cm. When filling, layer and compact every 5cm. After filling, cover the surface of the ecological restoration layer soil with an organic glass cover and let it stand for 24 hours. Water from the water tank (4) is delivered to the dripper (7) via a peristaltic pump (3) for drip irrigation. After drip irrigation begins, the peristaltic pump (3) and the solenoid valve control the process according to a time interval of denser to sparser water. A vertical wetting front profile is drawn on the plexiglass plate on the front of the soil tank, and a horizontal wetting front profile is drawn on the plexiglass cover plate above the soil of the ecological restoration layer. Points are taken on the vertical and horizontal wetting front profiles with the dripper as the origin, and wetting lines are drawn based on the horizontal and vertical coordinates of the points. The wetting distance R of the ecological restoration layer along the slope is measured based on the wetting lines. + 1. Wetting distance R of the ecological restoration layer in the reverse slope direction; 2. Wetting distance R of the ecological restoration layer in the transverse slope direction; 3. Maximum wetting width R in the transverse slope direction. max Infiltration depth H at the dripper, maximum infiltration depth H max Maximum wetting width offset distance L in the transverse slope direction R Maximum infiltration depth offset distance L H Eight characteristic parameters of the wetting front were obtained. Throughout the drip irrigation process, the moisture content, nutrients, electrical conductivity, and pH value of the soil sample were measured in real time by setting up a high-precision sensor array. By adjusting the slope, dripper flow rate, and irrigation volume using the controlled variable method, the movement pattern of the moist front under different variable conditions was obtained based on the measured characteristic parameters of the moist front movement. The distribution pattern of soil moisture and nutrients under different variable conditions was obtained based on the measured soil sample moisture content and nutrients.

3. The method for testing multimodal intelligent irrigation water transport in soil of slope ecological restoration layer according to claim 2, characterized in that: When drawing the wetting line, take the drip tip position as the origin on the glass panel, and take points on the contour of the wetting front in 18 directions in a clockwise direction at 15° intervals. Use a steel ruler to measure the horizontal and vertical coordinates of each point, and use AutoCAD software to draw the wetting line based on the horizontal and vertical coordinates of each point.

4. The method for testing multimodal intelligent irrigation water transport in slope ecological restoration layer soil according to claim 2, characterized in that: Throughout the drip irrigation process, a high-precision sensor array is set up to measure the soil sample's moisture content, nutrients, electrical conductivity, and pH value in real time. Based on the location of each sensor and its moisture content, the contour boundary of the wetting front is calculated and determined.

5. The method for testing multimodal intelligent irrigation water transport in soil of slope ecological restoration layer according to claim 2, characterized in that: Before mixing the ecological restoration layer soil, take the waste residue, air dry it, and then pass it through a 20mm sieve for later use. Take the planting soil, air dry it, crush it, and then pass it through a 2mm sieve for later use. Take the slope surface rock and soil for later use.

6. The method for testing multimodal intelligent irrigation water transport in soil of slope ecological restoration layer according to claim 2, characterized in that: Modified glutinous rice-based ecological restoration materials are formed by combining modified glutinous rice base material with soil particles and waste residue after encapsulation and adsorption to form aggregates, which enhances the water retention and erosion resistance of the soil. The modified glutinous rice base material includes glutinous rice flour, plant fiber, modifier and attapulgite slow-release fertilizer.

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