Precise irrigation system optimization method based on high and steep slope characteristics and dynamic threshold

Abstract

The invention relates to the technical field of slope stabilization, and discloses a precise irrigation system optimization method based on high and steep slope characteristics and a dynamic threshold, in the precise irrigation system optimization method, a'slope stability-irrigation threshold 'association mechanism is established by quantifying the critical water content theta c of the position, most prone to unbalance, of a high and steep rock slope; it is ensured that the water content of the representative easy-to-unbalance position after irrigation is smaller than or equal to theta c, and the slope instability risk is controlled; in combination with the water demand difference of grass and shrub, comprehensively considering the plant water demand, the plant wilting coefficient, the plant species and proportion and the soil key parameters, and determining a proper irrigation threshold interval; dynamic adjustment of irrigation volume and period is realized by fusing short-term weather forecast, and meanwhile, a bottom treatment mechanism for abnormal weather such as sudden heavy rain, sudden strong wind and high temperature is formulated; finally, the problems that in the prior art, side slope stability and irrigation requirements are completely disjointed, mixed plants are seriously insufficient in water requirement adaptability, irrigation regulation and control are static, and scientific basis is lacked are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of slope or slope stability, in particular to a precise irrigation system optimization method based on high and steep slope characteristics and dynamic threshold. BACKGROUND

[0002] In the field of ecological restoration of high and steep slopes (including high and steep rock, high and steep soil, etc.), irrigation system is the core technical link to ensure seed germination and slope stability of mixed spray seeding (herbaceous + shrub). Currently, the industry has not formed a special precise irrigation technology system for high and steep slope characteristics. The existing irrigation schemes mainly come from two sources: 1. Learn from farmland irrigation technology: such as patent CN116362402B discloses "farmland irrigation system based on weather forecast", the core goal is to improve farmland crop yield, by monitoring crop phenotype and short-term weather forecast to adjust irrigation amount, without involving slope stability related parameter design; 2. Follow the ordinary gentle slope irrigation scheme: mostly using "fixed cycle + fixed irrigation amount" mode (such as 3 days / time, 25m³ / mu single irrigation), only setting the minimum soil moisture content (such as 10%) by experience, without considering the special properties of high and steep slope, such as large slope (usually > 45°), thin substrate layer (usually < 30cm), fast water loss, and high water sensitivity of representative unstable positions (such as substrate-rock interface, surface loose soil layer); 3. Local rock slope irrigation attempt: some schemes are designed for gentle rock slope, although they mention water management at positions such as rock joints and substrate-rock interface, they do not extend to high and steep slope scenarios and do not establish a correlation mechanism between "slope stability threshold - irrigation parameters", which cannot meet the anti-instability requirements of high and steep slope.

[0003] These irrigation schemes have poor scene adaptability and cannot meet the common needs of high and steep slopes. The existing irrigation systems (including farmland and gentle slope schemes) do not design for the core pain points of high and steep slopes: they do not consider the uneven distribution of irrigation water caused by slope (slope top is easy to dry, slope bottom is easy to accumulate water), they do not design rigid stability threshold for high and steep slopes with high instability risk, and they do not adapt to the layered water requirement characteristics of mixed spray seeding plants. Even in high and steep rock slopes, it is difficult to apply, and it is easy to have "substandard stability" or "poor growth effect" problems. Specifically, there are the following defects, which make it difficult to meet the requirements of engineering application: 1. Slope stability and irrigation requirements are completely decoupled: the prior art only determines the irrigation amount according to the plant water requirement, and there is no perfect theory for whether to control and how to control the landslide, which only stays at the qualitative level of not watering too much, and relies on the irrigation workers to roughly judge according to the work experience. When irrigation is carried out, it often causes slope instability. The inventor found that the instability of high and steep slopes is very complex, and the high and steep slopes are not uniform, and there are some areas that are prone to instability due to the structure of the high and steep slopes, and some areas that are prone to instability due to the characteristics of the rock and soil. When controlling the irrigation amount of high and steep slopes, the non-uniformity needs to be considered.

[0004] It can easily cause the sudden drop of the bonding strength between the substrate and the rock surface (such as from 25kPa to 12kPa), the shear strength failure of the rock joint filling or the loose soil layer on the surface, and significantly improve the landslide risk of high and steep slopes; 2. Serious lack of mixed plant water adaptability: in the mixed spray-seeding of high and steep slopes, the herbaceous plants (such as dog tooth grass) have shallow root systems (10-15cm) and require surface water, and the shrubs (such as Amorpha fruticosa) have deep root systems (20-30cm) and require deep water. The prior art uses a single irrigation threshold (such as only one water content interval) and a single irrigation method (such as only micro-sprinkling or only drip irrigation), which is prone to "root rot of herbaceous plants due to flooding and wilting of shrubs due to lack of water", resulting in an imbalance in the biomass ratio of grass and shrubs (the herbaceous plant ratio often exceeds 80%), which violates the ecological restoration goal of "grass and shrub cooperation for slope stabilization" of high and steep slopes; 3. Static irrigation regulation and lack of scientific basis: the prior art mostly uses a fixed irrigation cycle (such as 3 days / once), without combining the characteristics of high and steep slopes such as fast water evaporation and fast loss after rain, and without integrating 1-7d short-term weather forecasts (rainfall, wind speed, air temperature) for dynamic adjustment; the minimum soil water content is set by the experience of engineers (such as 10%), without relating to the plant wilting coefficient and the water retention characteristics of the substrate, and unable to balance "deficit water saving" and "seed survival", and prone to seed wilting due to lack of water in high-temperature and windy weather. SUMMARY

[0005] The present application provides a precise irrigation system optimization method based on the characteristics of high and steep slopes and dynamic thresholds.

[0006] The technical problem to be solved is that when the existing high and steep slope is irrigated, the slope stability and irrigation requirements are completely decoupled, the mixed plant water adaptability is seriously insufficient, and the irrigation regulation is static and lacks scientific basis.

[0007] To solve the above technical problems, the present application adopts the following technical scheme: a precise irrigation system optimization method based on the characteristics of high and steep slopes and dynamic thresholds, which is used to ensure the irrigation effect and slope stability during the ecological restoration process of high and steep slopes, the high and steep slopes are covered with spray-seeding substrates, and the irrigation system optimization method comprises the following steps: Step one: carry out geological exploration on the slope, investigate rock types, key parameters of soil, and spray-broadcast base material formula, and find out representative unbalanced positions on the slope; The unbalanced positions satisfy the following two conditions simultaneously: Condition 1: In the sensitive area, the sensitive area is an area prone to sliding due to the structure of the slope; Condition 2: The rock-soil at the position is sensitive rock-soil, which is rock-soil prone to sliding due to its own characteristics; Step two: respectively measure the shear strength of the soil at different water contents in situ at each unbalanced position, draw a "water content-shear strength" curve, calculate the water content corresponding to the shear strength drop of each unbalanced position, and take the minimum value as the critical water content θ c ; Step three: based on the results of step one, calculate the minimum soil water content θ min based on the plant wilting coefficient, and the soil demand water content θ w based on the plant water requirement; Step four: compare θ c and θ w , take the minimum value as the maximum soil water content θ max , and based on the maximum soil water content, the minimum soil water content, the irrigation depth, and the soil bulk density, calculate the maximum single irrigation amount W single ; the maximum single irrigation amount is the maximum allowed irrigation water volume per unit area of land per irrigation; Step five: build an irrigation system on the high and steep slope, and set soil moisture sensors at the unbalanced positions found in step one; Step six: based on soil moisture sensor data and weather forecast data, make irrigation decisions to ensure that the maximum single irrigation amount is less than W single and the real-time soil water content is between θ max and θ min ; adjust irrigation before rainfall, and increase irrigation in high temperature or strong wind weather.

[0008] Further, the sensitive area includes the top of the slope, the foot of the slope, the inner and outer edges of the platform of multi-stage slope, the slope surface groove, and the depression; The sensitive rock-soil includes rock joint dense area, base material and complete rock surface junction area, and floating soil area; In step one, when finding representative unbalanced positions, find at least one unbalanced position in each sensitive area.

[0009] Further, in step one, when looking for representative unbalanced positions, first use the unmanned aerial vehicle to search for suspected sensitive rock and soil in each sensitive area, then use the geological hammer to explore the rock joint dense area, and use the test pit stripping method to explore the base material and the junction area of the complete rock surface and the floating soil area.

[0010] Further, in the process of geological exploration in step one, the exploration content of the spray seeding base material formula includes the type of spray seeding plants and the proportion of grass and shrub spray seeding, and the exploration content of the key parameters of the soil includes the soil bulk density ρ , the initial moisture content θ0, and the soil geological correction coefficient K s , wherein K s is valued according to the type of base material.

[0011] Further, for each plant of the spray seeding, the minimum soil moisture content θ min = θ pvp × (1+K d )×K s , wherein θ pvp is the wilting coefficient, and K d is the deficiency control coefficient. In step three, a minimum soil moisture content is calculated for each plant, and the maximum of them is selected as the minimum soil moisture content for the subsequent steps.

[0012] Further, in step three, the soil demand moisture content θ w = θ0+W mix / (h×10×ρ )×100%, wherein h is the irrigation influence depth, and W mix is the mixed plant water requirement, which is the sum of the product of the water requirement of each single plant and the proportion of the corresponding number of plants.

[0013] In step four, the single maximum irrigation amount W single =h×10×(θ max -θ min )×ρ .

[0014] Further, in step six, irrigation is carried out according to the following irrigation decision: Step 6.1: Take the average of the measurement results of each soil moisture sensor after removing outliers, and mark it as the real-time soil moisture content θ; at the same time, calculate the precipitation in the next seven days, and mark it as P; Step 6.2: The volume of water irrigated per unit area is marked as W; When θ≤θ min and P<5mm, start irrigation, and the termination condition of irrigation is W≥W single or θ≥θ max When θ≤θ minIrrigation is initiated when 5 ≤ P < 10 mm, and terminated when W ≥ W. single / 2 or θ≥θ max ; When θ≤θ min When P ≥ 10 mm, irrigation should be suspended; after rainfall stops, θ should be remeasured every 2-4 days. If θ ≥ θ max Drainage is carried out if θ≤θ min Return to step 6.1; In θ>θ min When θ ≥ θ, suspend irrigation. max Drainage is carried out, and then θ is remeasured every 2-4 days. If θ ≤ θ min Return to step 6.1; Step 6.3: Starting from the end of irrigation, record the local evaporation once a day and accumulate it. When the accumulated evaporation reaches a value not less than W at the end of the last irrigation, return to step 6.1.

[0015] Furthermore, in step two, an in-situ direct shear apparatus is used to measure the shear strength by gradually increasing the soil moisture content, starting from 10%.

[0016] Compared with existing technologies, the precision irrigation regime optimization method based on the characteristics and dynamic thresholds of steep slopes in this invention has the following advantages: In this invention, the critical water content θ at the most vulnerable location on a steep rock slope is quantified. c Establish a "slope stability-irrigation threshold" correlation mechanism to ensure that the water content of representative imbalance-prone locations is ≤θ after irrigation. c To control the risk of slope instability; Taking into account the differences in water requirements between grasses and irrigation systems, and comprehensively considering plant water requirements, plant wilting coefficients, plant species and proportions, as well as key soil parameters, a well-founded irrigation threshold range (θ) is determined. min ~θ max ); Integrating short-term weather forecasts enables dynamic adjustments to irrigation volume and cycle, while establishing a backup mechanism for handling abnormal weather such as sudden heavy rain, sudden strong winds, and high temperatures; Ultimately, this will solve the problems caused by existing technologies, such as the complete disconnect between slope stability and irrigation needs, the severe lack of water adaptability of mixed vegetation, and the static and unscientific nature of irrigation regulation. Attached Figure Description

[0017] Figure 1 This is a flowchart of the precision irrigation regime optimization method based on steep slope characteristics and dynamic thresholds according to the present invention; Figure 2 This is a flowchart of the irrigation decision in step six. Detailed Implementation

[0018] In this invention, "moisture content" and "soil moisture" both refer to soil volumetric moisture content.

[0019] like Figure 1 As shown, a precise irrigation regime optimization method based on the characteristics and dynamic thresholds of steep slopes is used to simultaneously ensure irrigation effectiveness and slope stability during the ecological restoration of steep slopes. The steep slopes are covered with hydroseeding substrate. The irrigation regime optimization method includes the following steps: Step 1: Conduct a geological survey of the slope to investigate the rock type, key soil parameters, and hydroseeding substrate formulation, and identify representative locations on the slope that are prone to imbalance. A location prone to imbalance must simultaneously meet the following two conditions: Condition 1: In sensitive locations, the sensitive location is a location prone to landslides due to the structure of the slope; The sensitive location here means that even if the slope is made of completely homogeneous rock and soil, it is a location that is prone to landslides due to its location. Condition 2: The soil and rock at the location are sensitive soil and rock, which are soil and rock that are prone to sliding due to their inherent properties; The sensitive soil and rock here refers to soil and rock that are prone to slippage even on a single-stage slope with uniform gradient and an infinitely large area, due to the properties of the soil and rock itself.

[0020] Step 2: Measure the shear strength of the soil at different moisture contents at each location prone to imbalance, plot the "moisture content-shear strength" curve, calculate the moisture content corresponding to the sharp drop in shear strength at each location prone to imbalance, and take the lowest value as the critical moisture content θ. c ; When soil moisture content exceeds the critical moisture content, shear strength drops sharply, leading to landslides. Therefore, the lowest moisture content corresponding to the sharp drop in shear strength at each easily imbalanced location is selected here, i.e., the inflection point of the sharp drop in shear strength. Note that shear strength cannot be sampled here, as sampling would damage the soil structure and disrupt its interaction with the local environment.

[0021] Step 3: Based on the geological survey results from Step 1, determine the minimum soil moisture content θ using the plant wilting coefficient. min Soil moisture requirement θ is determined based on plant water requirements. w ; Step 4: Compare θ c With θ w Take the minimum value among them as the highest soil moisture content θ. max Based on the highest soil moisture content, lowest soil moisture content, irrigation depth, and soil bulk density, the maximum irrigation volume W for a single irrigation is calculated. singleThe maximum single irrigation volume is the maximum volume of water allowed to be irrigated per unit area of ​​land per irrigation session. Step 5: Construct an irrigation system on the steep slope and install soil moisture sensors at the locations prone to imbalance identified in Step 1; The irrigation system constructed in this embodiment is a micro-sprinkler irrigation + drip irrigation composite system, with micro-sprinkler irrigation supplying the surface herbaceous plants and drip irrigation supplying the deep shrubs.

[0022] Step Six: Based on soil moisture sensor data and weather forecast data, make irrigation decisions to ensure that the maximum irrigation amount per cycle is less than W. single And the real-time soil moisture content is at θ max With θ min Adjust irrigation during periods of impending rainfall and increase irrigation amounts during periods of high temperature or strong winds.

[0023] In this embodiment, sensitive locations include the top of the slope, the toe of the slope, the inner and outer edges of the multi-level sloping platform, the slope grooves, and depressions; Sensitive soil and rock include areas with dense rock fissures, the interface between the substrate and the intact rock surface, and areas with loose soil. In step one, when searching for representative locations prone to imbalance, at least one location prone to imbalance should be found in each sensitive area.

[0024] Here, "representative locations prone to imbalance" means that each sensitive area has at least one location prone to imbalance, which ensures the critical moisture content θ. c The calculations are not biased, and when setting the soil moisture sensor in step five, it is ensured that each sensitive area is taken into account.

[0025] In step one, when searching for representative locations prone to imbalance, drones are first used to search for suspected sensitive soil and rock in each sensitive area. Then, geological hammers are used to investigate areas with dense rock fissures, and test pit stripping methods are used to explore the interface between the substrate and the intact rock surface, as well as the loose soil area.

[0026] In the geological exploration process of step one, the exploration content for the hydroseeding substrate formulation includes the type of hydroseeding plants and the ratio of grasses and shrubs, and the exploration content for key soil parameters includes soil bulk density ρ. Initial moisture content θ0 and soil geological correction coefficient K s K s Values ​​are assigned based on substrate type.

[0027] Soil bulk density ρ Determined by ring cutter method, with values ​​ranging from 1.3 to 1.5 g / cm³. 3 ; Initial moisture content θ0: measured by a handheld moisture meter, with values ​​ranging from 8% to 12%; Soil geological correction factor K sThe value is determined by the type of substrate (sandy 1.1~1.2, loamy 1.0, clayey 0.9~0.95).

[0028] For each type of plant seeding, the minimum soil moisture content θ min =θ pvp ×(1+K d )×K s In the formula, θ pvp K is the wilting coefficient. d The deficit control coefficient is used; the wilting coefficient and the deficit control coefficient are obtained from literature and / or industry standards (such as the Technical Specification for Water-Saving Irrigation Engineering).

[0029] Example: Wilting coefficient of Cynodon dactylon 5%~6%, Amorpha fruticosa 8%~9%; Deficiency regulation coefficient: 0.1~0.2 for drought-tolerant plants, 0.3~0.4 for other plants; specifically, θ for Amorpha fruticosa. pvp =8%, K d =0.3, K s =1.1, at this time θ min ≈11%.

[0030] In step three, a minimum soil moisture content is calculated for each type of plant, and the largest one is selected as the minimum soil moisture content for subsequent steps.

[0031] In step three, the required soil moisture content θ w =θ0+W mix / (h×10×ρ )×100%, where h is the depth of irrigation influence, W mix The water requirement for mixed plants is generally expressed in mm, and is the sum of the products of the water requirement of each individual plant species and the corresponding percentage of plant numbers.

[0032] The percentage of seeds in the hydroseeding substrate formulation investigated in step one, multiplied by the corresponding germination rate, yields the percentage of plantlets. The water requirement per plant species is obtained from literature and / or industry standards (such as the "Technical Specification for Water-Saving Irrigation Engineering"), typically in mm.

[0033] In step four, the maximum single irrigation volume W single =h×10×(θ max -θ min )×ρ W single The unit is usually mm, meaning the depth of irrigation water on one square meter of land when evenly spread over that square meter. It can also be converted to cubic meters per mu (unit of land area). Example: h = 30cm, θ max =17.6%, θ min =11%, ρ =1.4g / cm³, W single =27.72mm, which translates to an irrigation volume of ≈18.5m³ / mu.

[0034] This value is like Figure 2 As shown, in step six, irrigation is carried out according to the following irrigation decisions: Step 6.1: After removing outliers from the measurement results of each soil moisture sensor, take the average and record it as the real-time soil moisture content θ; at the same time, calculate the seven-day forecast precipitation and record it as P. Step 6.2: The volume of water irrigated per unit area in this irrigation is denoted as W; When θ≤θ min Irrigation is initiated when P < 5 mm, and terminated when W ≥ W. single or θ≥θ max When θ≤θ min Irrigation is initiated when 5 ≤ P < 10 mm (light rain), and terminated when W ≥ W. single / 2 or θ≥θ max ; When θ≤θ min When P ≥ 10 mm (moderate rain or above), irrigation should be suspended; after rainfall stops, θ should be remeasured every 2-4 days. If θ ≥ θ max Drainage is carried out if θ≤θ min Return to step 6.1; In θ>θ min When θ ≥ θ, suspend irrigation. max Drainage is carried out, and then θ is remeasured every 2-4 days. If θ ≤ θ min Return to step 6.1; Step 6.3: Starting from the end of irrigation, record the local evaporation (also in mm) once a day and accumulate it. When the accumulated evaporation reaches a value not less than W at the end of the last irrigation, return to step 6.1.

[0035] Local evaporation data is available through the National Meteorological Administration's data service, the China Meteorological Data Network, or hydrological information and forecasts released by local governments. Although not reported in official weather forecasts, meteorological departments measure this value during their operations, and it comprehensively reflects the effects of temperature and wind. Irrigation needs to resume when evaporation is no less than the amount irrigated previously.

[0036] In step two, an in-situ direct shear apparatus is used to measure shear strength by gradually increasing the soil moisture content, starting from 10%. In this embodiment, the soil moisture content is measured every 5% increase, generally up to about 30%. After the measurements are completed, a moisture content-shear strength curve is plotted to identify the moisture content corresponding to a sharp drop in shear strength. This moisture content is generally between 20% and 30%.

[0037] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for optimizing precise irrigation regime based on the characteristics of high and steep slope and dynamic threshold, for simultaneously ensuring the irrigation effect and slope stability in the process of ecological restoration of high and steep slope, wherein the high and steep slope is covered with spray-seeding substrate, characterized in that: The irrigation system optimization method comprises the following steps: ​ Step one: carry out geological exploration on the slope, explore rock type, soil key parameters and spray seeding base material formula, and find out representative unbalanced positions on the slope; The unbalanced position meets the following two conditions at the same time: Condition 1: in the sensitive area, the sensitive area is an area prone to sliding due to the structure of the slope; Condition 2: the rock-soil at the position is sensitive rock-soil, which is rock-soil prone to sliding due to its own characteristics; Step two: in each position, the shear strength of soil at different water content is measured in situ, and the "water content-shear strength" curve is drawn to find the water content corresponding to the shear strength drop, and the lowest value is taken as the critical water content θ c ; Step three: Based on the results of the geological exploration in step one, the minimum soil moisture content θ is calculated based on the wilting coefficient of the plant min The soil demand moisture content θ is calculated based on the water requirement of the plant w ; Step four: compare θ c with θ w , take the minimum value as the highest soil moisture content θ max ; based on the highest soil moisture content, the lowest soil moisture content, the irrigation depth, the soil bulk density, the single maximum irrigation amount W single is calculated; the single maximum irrigation amount is the maximum allowed irrigation water volume per unit area of land per irrigation; Step five: build an irrigation system on the high and steep slope, and set soil moisture sensors at the unbalanced positions found in step one; Step six: Irrigation decision based on soil moisture sensor data and weather forecast data, ensuring that the maximum amount of irrigation at a single time is less than W single and the real-time soil water content is between θ max and θ min ; adjust irrigation before rainfall and increase irrigation amount in high temperature or strong wind weather.

2. The method of claim 1, wherein the method is characterized by: The sensitive area includes the top of the slope, the foot of the slope, the inner and outer edges of the platform of multi-stage slope, the slope groove and the depression; The sensitive rock-soil includes the rock joint dense area, the base material and the complete rock surface junction area, and the floating soil area; In step one, when looking for representative unbalanced positions, find at least one unbalanced position in each sensitive area.

3. The method of claim 2, wherein the method is characterized by: In step one, when looking for representative unbalanced positions, first search for suspected sensitive rock-soil in each sensitive area with a drone, then explore rock joint dense areas with a geological hammer, and explore base material and complete rock surface junction areas and floating soil areas with a test pit stripping method. 4.The method of claim 1, wherein the method further comprises: determining a dynamic threshold value based on a characteristic of a high steep slope; and determining the irrigation schedule based on the dynamic threshold value. In the process of the first step of the geological exploration, the exploration content of the spray seeding base material formula includes the spray seeding plant type and the ratio of grass and shrub, and the exploration content of the key parameters of the soil includes the soil bulk density ρ , the initial moisture content θ0, and the soil geological correction coefficient K s , wherein K s is valued according to the type of the base material.

5. The method of claim 4, wherein the method is characterized by: For each plant species in the spray seeding, the minimum soil water content θ min =θ pvp ×(1+K d )×K s , wherein θ pvp is the wilting coefficient, and K d is the deficit regulation coefficient. In step three, calculate a minimum soil moisture content for each plant, and select the maximum as the minimum soil moisture content for the subsequent steps. 6.The method of claim 4, wherein the method further comprises: determining a dynamic threshold value based on a characteristic of the high steep slope; and determining the irrigation schedule based on the dynamic threshold value. In step three, the soil requirement moisture content θ w = θ0+ W mix / (h × 10 × ρ ) × 100%, wherein h is the irrigation influence depth, W mix is the mixed plant water requirement, which is the sum of the product of the water requirement of each single plant and the corresponding proportion of the number of plants. In step four, the single maximum irrigation amount W single = h x 10 x (θ max - θ min ) x p .

7. The method of claim 1, wherein the method is characterized by: In step six, irrigation is carried out according to the following irrigation decision: Step 6.1: take the average of the measurement results of each soil moisture sensor after removing outliers, and mark it as the real-time soil moisture content θ; At the same time, calculate the seven-day weather forecast precipitation, marked as P; Step 6.2: the volume of water irrigated per unit area at this time is marked as W; When θ ≤ θ min and P < 5 mm, irrigation is started, and the irrigation termination condition is W ≥ W single or θ ≥ θ max When θ≤θ min , and 5≤P<10mm, irrigation is started, and the irrigation termination condition is W≥W single / 2 or θ≥θ max ; When θ ≤ θ min , and P ≥ 10 mm, irrigation is suspended; after precipitation stops, θ is retested every 2-4 days, if θ ≥ θ max , drainage is performed, if θ ≤ θ min , return to step 6.1; When θ > θ min , irrigation is suspended, and if θ ≥ θ max , drainage is performed, and then θ is measured again every 2-4 days, and if θ ≤ θ min , return to step 6.

1. Step 6.3: from the end of irrigation, record the local evaporation amount once a day and accumulate, when the evaporation amount accumulated is not less than W at the last irrigation end, return to step 6.

1.

8. The method for optimizing precise irrigation regimes based on steep slope characteristics and dynamic thresholds according to claim 1, characterized in that: In step two, the in-situ direct shear apparatus is used to measure the shear strength with a gradient increase in soil moisture content from 10% soil moisture content.

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