Method for precise application of water and fertilizer by spraying in mulberry garden

Abstract

The application discloses a method for precise application of water and fertilizer in mulberry garden by sprinkling irrigation, and comprises the following steps: according to a preset sprinkler jurisdiction area and water and fertilizer application amount per unit area, the total amount of water and fertilizer sprayed by the sprinkler is calculated; according to the total amount of water and fertilizer application of the sprinkler, the total amount of water and fertilizer of the sprinkler is timely adjusted through an electronic metering switch and a control system; a pressure sensor is arranged on an outlet pipeline of the sprinkler to form a closed loop control circuit with a variable frequency device, and the rotating speed of the variable frequency motor is dynamically adjusted through a PID algorithm; according to a preset fertilizer application requirement, a mother liquor of different element fertilizers is configured; the mother liquor and water are extracted by a water pump and a variable frequency motor according to a set proportion; and the variable frequency motor is controlled to accurately mix and apply the different element fertilizers. The application can timely obtain the information of water and fertilizer elements of the soil by installing a monitoring probe to monitor the soil condition in real time. The monitoring data are transmitted to the control system, and the water and fertilizer application amount is adjusted accordingly, so that the dynamic and precise management of water and fertilizer in the mulberry garden is realized.

Description

Technical Field

[0001] This invention belongs to the field of mulberry planting technology, specifically relating to a method for precise application of water and fertilizer in mulberry orchards via sprinkler irrigation. Background Technology

[0002] Traditional mulberry orchard water and fertilizer management often relies on a combination of manual experience and extensive irrigation, resulting in inaccurate application control and uneven nutrient distribution. Because mulberry trees have significantly different water and fertilizer requirements at different growth stages, existing methods struggle to provide precise, on-demand supply, often leading to excessive fertilization in certain areas causing soil compaction, or insufficient application affecting mulberry leaf yield. Regarding irrigation equipment, ordinary sprinkler systems lack dynamic adjustment capabilities. When pipeline pressure fluctuates, the sprinkler head rotation speed becomes unstable, directly impacting the uniformity of spray coverage. Particularly in mulberry orchards with undulating terrain, traditional sprinklers cannot automatically compensate for terrain differences, resulting in insufficient irrigation in high-slope areas and waterlogging in low-lying areas.

[0003] The water and fertilizer mixing process often uses a fixed ratio, which cannot be adjusted according to real-time soil monitoring data, leading to a mismatch between nutrient supply and crop needs. Existing solenoid valves typically have a control accuracy of ±5% or higher, and are prone to cumulative errors when adding micronutrients. Furthermore, traditional systems lack a clogging warning mechanism; when filters become clogged, the entire system often shuts down for maintenance, severely impacting irrigation continuity. While current technologies attempt to improve control accuracy by adding sensors, the high complexity of multi-parameter collaborative control algorithms and the delays in data interaction between different subsystems make truly real-time, precise control difficult. Especially when multiple sprinklers operate in tandem, traditional centralized control systems have slow response times, failing to meet the timeliness requirements of differentiated irrigation in different zones.

[0004] Therefore, there is an urgent need to develop a method for precise application of water and fertilizer in mulberry orchards using sprinkler irrigation, which features dynamic compensation, precise proportioning, and intelligent control. Summary of the Invention

[0005] The object of the present invention is to overcome at least the aforementioned defects and to provide advantages that will be described later.

[0006] To achieve these objectives and other advantages of the present invention, a method for precise application of water and fertilizer through sprinkler irrigation in mulberry orchards is provided, comprising: Calculate the total amount of water and fertilizer sprayed by the nozzle based on the preset area covered by the nozzle and the amount of water and fertilizer applied per unit area.

[0007] Based on the total amount of water and fertilizer applied by the nozzle, the total amount of water and fertilizer applied by the nozzle is adjusted in a timely manner through electronic metering switches and control systems.

[0008] A pressure sensor is installed in the nozzle outlet pipeline to form a closed-loop control circuit with the frequency converter. The speed of the frequency converter motor is dynamically adjusted through the PID algorithm to keep the nozzle rotation angular velocity stable at 0.1~0.3 rad / s.

[0009] Prepare stock solutions of different element fertilizers according to the preset fertilization requirements.

[0010] The mother liquor and clean water are extracted according to a set ratio using a water pump and a variable frequency motor.

[0011] The variable frequency motor is controlled to precisely mix and apply fertilizers of different elements.

[0012] In the above scheme, by accurately calculating the amount of water and fertilizer applied per unit area and adjusting the total amount of water and fertilizer from the sprinklers in real time, waste or deficiency of water and fertilizer can be avoided. Using frequency converters to set a fixed pressure ensures uniform spraying from sprinklers at different distances, improving the balance of water and fertilizer distribution. Precisely mixing and applying different elemental fertilizer stock solutions can meet the nutritional needs of mulberry trees at different growth stages, promoting healthy growth, increasing mulberry leaf yield and quality, while also improving water and fertilizer utilization efficiency and reducing production costs.

[0013] Preferably, the method for precise application of water and fertilizer in mulberry garden sprinkler irrigation also includes: a controller, wherein the control logic of the controller and the variable frequency motor includes: dividing the sprinkler head into N control groups, the sprinkler head control group adopts a modular regional control architecture, each control module independently manages 3 to 5 sprinkler heads, and adjacent control modules are connected by shielded twisted pair cables to form a ring communication network.

[0014] Each control module has a built-in main control unit and a backup control unit. The main control unit receives the reference speed command from the central controller in real time, and the backup control unit continuously monitors the working status of the main control unit. When the main control unit fails, it seamlessly takes over control within 0.5 seconds.

[0015] The variable frequency motor speed regulation adopts a graded compensation mechanism: when the pressure sensor detects a pipeline pressure fluctuation ≤0.2MPa, the motor speed is finely adjusted through the PID algorithm, and the compensation range does not exceed ±2% of the set value; when the pressure fluctuation is >0.2MPa, it automatically switches to the preset pressure-speed compensation curve for coarse adjustment, and at the same time sends a pressure warning signal to the adjacent control module.

[0016] Preferably, the preparation of the mother liquor specifically includes: setting up at least three parallel mother liquor tanks to store nitrogen-based mother liquor, phosphorus-based mother liquor, and potassium-based mother liquor respectively, and each mother liquor tank is connected to a direct-acting solenoid valve with a valve opening accuracy of ±2%; the mother liquor and clean water are mixed through a three-way proportional valve, and the opening ratio of each mother liquor valve is dynamically adjusted so that the deviation of the concentration of each element in the mixture from the preset ratio does not exceed 5%; the mixed solution flows through a static mixer with built-in 60° staggered guide vanes, and the surface of the guide vanes is coated with a polyethylene anti-adhesion coating.

[0017] Preferably, the method for precise application of water and fertilizer through sprinkler irrigation in mulberry orchards also includes: Soil nutrient monitoring units are evenly spaced at a soil depth of 15-25cm in the mulberry orchard. Each monitoring unit integrates a conductivity sensor and a moisture sensor. Soil EC value and moisture content data are collected every 1 hour. The data is sent to the central controller via a low-power wireless transmission module. The central controller has a built-in irrigation decision algorithm.

[0018] Irrigation is activated when the measured soil electrical conductivity is more than 0.3 mS / cm lower than the preset value or the measured soil moisture content is less than 5% of the field capacity of the soil type. When applying rainfall deduction, the compensation coefficient K = 1 - 0.5 × (actual rainfall / 10 mm) and K ≥ 0.4.

[0019] A Venturi fertilizer applicator is installed 1.2 to 1.5 meters upstream of the turbine flow meter on the main pipeline, between the diameter expansion section and the rectifier grid. The Venturi fertilizer applicator is equipped with a vacuum maintenance device, including a 5L vacuum buffer tank and an electric vacuum pump connected in series. It automatically starts when the negative pressure at the suction inlet is lower than -0.075MPa, and maintains a working pressure of -0.075 to -0.085MPa.

[0020] When injecting liquid compound fertilizer mother liquor, a diameter expansion section is set upstream of the turbine flow meter to stabilize the local flow velocity at 2.3~2.7m / s.

[0021] Preferably, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation also includes: terrain adaptive compensation and spray trajectory optimization algorithm execution: a) After the sprinkler speed is increased in high slope areas, the spraying interval between adjacent sprinklers is shortened by Δt=0.12×(α / 8°) seconds, where α is the tilt angle; b) During the extended spraying time in low-lying areas, the sprinkler elevation angle is lowered by 3°~5° and the anti-drift mode is activated; The global pressure compensation value is calculated as P=0.5+0.025×(α-8)MPa, where α>8°.

[0022] Preferably, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation also includes: setting up an anti-interference calibration module for calibration: using a laser rangefinder to perform on-site calibration of the spray coverage diameter every month, with a maximum allowable deviation of ±0.15 meters; collecting fertilizer penetration depth data from 10 sampling points every quarter using a mobile soil tester to dynamically correct the mother liquor ratio parameters; and controlling the speed fluctuation of the variable frequency motor within ±3% of the set value.

[0023] Preferably, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation also includes anti-clogging control, specifically including a four-stage treatment process: The first-level processing is as follows: when the flow meter detects an instantaneous flow rate drop of 10%~15% that lasts for 30 seconds, the variable frequency motor speed is increased to 150% of the rated value for 5 seconds, and the pipeline pressure is maintained at 1.2 times the working pressure.

[0024] The secondary treatment is as follows: if the flow rate does not recover to 95% of the normal value within 60 seconds after the primary treatment, a 20Hz gas-liquid pulse wave impact is initiated. The pulse wave is generated alternately by 0.8MPa compressed air and 1.5MPa water flow, with 5 pulses per cycle, and is executed continuously for 3 cycles.

[0025] The third-level treatment is as follows: If the flow rate is still lower than 90% of the normal value within 120 seconds after the second-level treatment, switch to the backup pipeline and inject 0.1% citric acid solution, and circulate and flush for 10 minutes at a flow rate of 20L / min.

[0026] The fourth-level processing is as follows: when the blockage location signal originates from the mother liquor tank outlet, the filter screen is automatically switched to 80 mesh and a fault code is generated, and the backup mother liquor supply pipeline is started simultaneously.

[0027] Preferably, the EC value threshold setting specifically includes: setting it to 1.2~1.5mS / cm for the first 15 days of budding, and increasing it by 0.02mS / cm daily for the first 16~30 days; the EC threshold for the maturity period is dynamically adjusted according to the SPAD value of mulberry leaves: when the SPAD measured by the handheld chlorophyll meter is <42, it is set to 2.6mS / cm, and when SPAD is ≥42, it is set to 2.0mS / cm, and the sensor is calibrated every 48 hours.

[0028] Preferably, the method for precise application of water and fertilizer in mulberry garden sprinkler irrigation also includes: after irrigation, the water content distribution is detected by five soil moisture sensors distributed at the four corners and the center of the mulberry garden plot. The central controller compares the data of each sensor. When the difference in water content between any two monitoring points exceeds 3%, the geographical coordinates of the area with the largest difference are stored in the priority irrigation queue.

[0029] Preferably, the method for precise application of water and fertilizer in mulberry garden sprinkler irrigation also includes: the central controller receives 24-hour rainfall data sent by the weather station every day. If the rainfall reaches 5mm, the preset irrigation schedule will be delayed by 24 hours. If the rainfall reaches 10mm, the irrigation water quota will be reduced by 50% of the rainfall in the next irrigation plan.

[0030] Advantages of this invention: First, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of this invention controls the application error to within ±2% through precise calculation and closed-loop control at the sprinkler head level. A PID algorithm is used to dynamically adjust the motor speed, stabilizing the sprinkler head rotation speed within the optimal range and ensuring a spray coverage uniformity of over 90%.

[0031] Secondly, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of the present invention can achieve precise proportioning of three or more element fertilizers through a modular mother liquor preparation system, and improve the fertilizer mixing uniformity to 95% when combined with a static mixer. The entire system can save more than 30% of water and fertilizer usage, significantly improving the water and fertilizer utilization efficiency of mulberry orchards in hilly areas.

[0032] Furthermore, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of this invention utilizes a modular control architecture to ensure that the failure of a single control module does not affect the overall system, with a seamless switching time between main and backup units of ≤0.5 seconds, improving system reliability by 40%. A graded compensation mechanism switches to a preset compensation curve when pressure fluctuations >0.2MPa, improving response speed and achieving pressure stability of ±0.05MPa. A digital moving average filter enhances the signal-to-noise ratio to over 35dB, effectively suppressing electromagnetic interference and ensuring control command transmission accuracy ≥99%. A ring communication network reduces data transmission delay between adjacent modules to <10ms, meeting the real-time requirements of multi-sprinkler collaborative operation.

[0033] Furthermore, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of this invention allows for independent control of the three elements through a parallel mother liquor tank design, shortening the response time for ratio adjustment to within 5 seconds. A direct-acting solenoid valve with ±2% accuracy controls element concentration deviation within 5%, reducing the risk of nutrient imbalance. A 60° staggered guide vane generates a turbulent effect, achieving a 98% uniformity of the mixed liquor. A polyethylene coating reduces fertilizer crystallization adhesion by 80%, extending the mixer maintenance cycle to over 6 months. The three-way proportional valve achieves a dynamic adjustment accuracy of 1%, enabling instantaneous and precise ratio mixing of mother liquor and clean water.

[0034] Furthermore, in the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of this invention, the soil in-situ monitoring unit collects data every hour, improving efficiency by 24 times compared to traditional manual detection. When the EC value falls below the threshold twice consecutively, the system initiates zoned irrigation within 30 seconds, increasing response speed by 90%. The Venturi fertilizer applicator has an adjustable suction ratio range of 1:80~120, meeting the precise supplementation needs of different degrees of nutrient deficiency. Real-time monitoring by the turbine flow meter ensures that the dynamic adjustment error of fertilizer application is less than 3%, and the gradient deceleration mechanism at the end of irrigation avoids water hammer effects, extending equipment life by 20%. Irrigation logs automatically record key parameters, providing data support for subsequent optimization.

[0035] Furthermore, the method for precise water and fertilizer application in mulberry orchard sprinkler irrigation of this invention uses a tilt sensor to detect terrain tilt in real time. In low-lying areas, the pressure is increased by 0.5~0.7 MPa, increasing the spray range by 15%, while in high-slope areas, the rotation speed is increased by 5%~8% to ensure stable coverage radius. The single-nozzle tilt compensation response time is less than 2 seconds. After the global pressure compensation mode is activated, the irrigation uniformity in undulating terrain areas is improved to over 85%. The intelligent spraying time adjustment function reduces the difference in water distribution per unit area on slopes from 30% in traditional systems to 8%, effectively solving the problem of uneven irrigation caused by terrain.

[0036] Furthermore, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of this invention controls the spray diameter deviation within ±0.15 meters through quarterly calibration using laser ranging, increasing coverage by 12%. A mobile detector samples at 10 points to correct mother liquor parameters, ensuring the actual penetration depth deviates from the design value by ≤5cm. The variable frequency motor speed fluctuation is ≤±3%, improving stability by 50% compared to traditional systems. The dynamic calibration mechanism allows the system to maintain 95% of its initial accuracy even after long-term operation (after 12 months), reducing maintenance frequency by 60%.

[0037] Furthermore, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of this invention achieves a 99% interception efficiency through a 100-mesh filter, and the backwash filter reduces the pipe blockage rate by 70%. In the three-stage blockage handling mechanism, a 200ms high-pressure pulse clears 85% of minor blockages, and switching to a backup pipeline can restore irrigation within 45 seconds. Blockage location codes are accurately pinpointed to within 3 meters, reducing troubleshooting time by 80%. The system's annual unplanned downtime is reduced to less than 4 hours, and continuous operation capability is increased fivefold.

[0038] Furthermore, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of the present invention sets different soil EC value thresholds according to different periods, accurately matching the root development needs of mulberry trees and reducing waste caused by ineffective fertilization.

[0039] Furthermore, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of this invention improves the speed of identifying unevenly irrigated areas by 10 times compared to traditional methods through five-point distributed detection. A 3% moisture content difference threshold triggers priority irrigation, reducing the moisture difference between areas from 12% to less than 5%. The geographic coordinate storage function shortens the re-irrigation response time in key areas to 30 minutes and reduces the incidence of drought patches by 65%.

[0040] Furthermore, the method for precise application of water and fertilizer in mulberry orchard sprinkler irrigation of this invention improves the accuracy of dynamic adjustment of irrigation plans by 40% through meteorological data integration, saves 20% of irrigation water through a 5mm rainfall delay strategy, and reduces annual water consumption by 8% through a 10mm rainfall offset mechanism. The meteorological response module reduces the number of invalid system starts during the rainy season by 75%, and combined with soil moisture data, the overall water-saving benefit reaches 15%~25%. The automatic scheduling function reduces the frequency of manual intervention by 80%, realizing truly intelligent irrigation management. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0042] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0043] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0044] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "configuration" should be interpreted broadly. For example, they can refer to a fixed connection or configuration, a detachable connection or configuration, or an integral connection or configuration. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] Example 1 Methods for precise application of water and fertilizer in mulberry orchard sprinkler irrigation include: Step 1: Calculate the total amount of water and fertilizer to be sprayed by the nozzle based on the preset area covered by the nozzle and the amount of water and fertilizer applied per unit area.

[0046] Step 2: Based on the total amount of water and fertilizer applied by the nozzle, adjust the total amount of water and fertilizer applied by the nozzle in a timely manner through the electronic metering switch and control system.

[0047] Step 3: Install a pressure sensor in the nozzle outlet pipeline to form a closed-loop control circuit with the frequency converter. Use a PID algorithm to dynamically adjust the speed of the frequency converter motor to stabilize the nozzle rotational angular velocity at 0.1~0.3 rad / s.

[0048] Step 4: Prepare stock solutions of different element fertilizers according to the preset fertilization requirements.

[0049] Step 5: Extract mother liquor and clean water according to the set ratio using a water pump and variable frequency motor.

[0050] Step 6: Control the variable frequency motor to precisely mix and apply fertilizers of different elements.

[0051] Specifically, the electronic metering switch uses an AZBIL VH-F10 electromagnetic flowmeter; the pressure sensor uses a Honeywell 26PCFFA6G micro-pressure sensor; and the variable frequency motor uses an ABB ACS880-01 series variable frequency drive motor. During implementation, the coverage radius of each sprinkler head (Nelson R33 model) is first measured using a GIS system, and the managed area S = π × r² is calculated. Then, based on the needs of the mulberry tree's growth period, the application rate per unit area Q is set (e.g., 1.5 L / m² during the budding stage), and the total application rate per sprinkler head = S × Q. The flow rate is then monitored in real time by the electromagnetic flowmeter, and the central controller (SIEMENSS7-1200 PLC model) compares the actual value with the set value and automatically adjusts the valve opening. A pressure sensor is installed at the sprinkler outlet to transmit the pressure signal to the variable frequency motor. PID parameters (P = 0.8, I = 0.05, D = 0.1) are used to dynamically adjust the motor speed, maintaining the sprinkler head speed at 3.0 ± 0.1 rad / s. Nitrogen, phosphorus, and potassium mother liquor tanks (500L capacity) are connected to Burkert 6011 solenoid valves respectively. The mother liquor is drawn according to the preset ratio (e.g., N:P:K=3:1:2), mixed with clean water through a Komax 340 static mixer (flow rate 2.5m / s), and then transported to the main pipeline.

[0052] This implementation plan ensures a uniformity of element mixing of >95% through precise calculation and dynamic control of total water and fertilizer application, thus solving the problems of waste and insufficient fertilizer efficiency caused by the extensive application of water and fertilizer and uneven mixing in traditional sprinkler irrigation systems.

[0053] Example 2 Based on Embodiment 1, it also includes: a controller and presets the controller.

[0054] The control logic of the controller and the variable frequency motor includes: dividing the nozzles into N control groups, the nozzle control group adopts a modular area control architecture, each control module independently manages 3 to 5 nozzles, and adjacent control modules are connected by shielded twisted pair cables to form a ring communication network.

[0055] Each control module has a built-in main control unit and a backup control unit. The main control unit receives the reference speed command from the central controller in real time, and the backup control unit continuously monitors the working status of the main control unit. When the main control unit fails, it seamlessly takes over control within 0.5 seconds.

[0056] The variable frequency motor speed regulation adopts a graded compensation mechanism: when the pressure sensor detects a pipeline pressure fluctuation ≤0.2MPa, the motor speed is finely adjusted through the PID algorithm, and the compensation range does not exceed ±2% of the set value; when the pressure fluctuation is >0.2MPa, it automatically switches to the preset pressure-speed compensation curve for coarse adjustment, and at the same time sends a pressure warning signal to the adjacent control module.

[0057] Specifically, this implementation scheme uses a BELDEN 8761 double-shielded industrial bus for shielded twisted-pair cabling; the main control unit uses a SIEMENS S7-1200 PLC. During implementation, every four nozzles form a control module, and the modules are connected in a ring network via BELDEN 8761 twisted-pair cabling, using the Modbus RTU communication protocol at a baud rate of 19200bps. The main control unit receives speed commands in real time, and the backup unit checks the main control unit's heartbeat signal every 100ms. If the heartbeat signal is lost five times consecutively, the main control unit takes over control within 0.5 seconds. When the pressure fluctuation is ≤0.2MPa, the PID algorithm adjusts the speed in ±2% steps; when the fluctuation is >0.2MPa, it switches to a preset curve, increasing the speed by 5% for every 0.1MPa increase in pressure, and sends a warning code to adjacent modules via RS485. This implementation scheme achieves a speed control accuracy of ±0.5% and a fault switching response time of 0.3 seconds.

[0058] Example 3 Based on Example 1, the preparation of the mother liquor specifically includes: Set up at least three mother liquor tanks in parallel to store nitrogen-based mother liquor, phosphorus-based mother liquor, and potassium-based mother liquor respectively, and connect each mother liquor tank to a direct-acting solenoid valve with a valve opening accuracy of ±2%.

[0059] The mother liquor and water are mixed through a three-way proportional valve. The opening ratio of each mother liquor valve is dynamically adjusted to ensure that the concentration of each element in the mixture does not deviate from the preset ratio by more than 5%.

[0060] The mixed solution flows through a static mixer with built-in 60° staggered guide vanes, the surface of which is coated with a polyethylene anti-adhesion coating.

[0061] Specifically, this implementation scheme uses a Burkert 6011 direct-acting solenoid valve and a Komax 340 series flow-guided mixer. During implementation, the nitrogen-based mother liquor is a 20% urea solution, the phosphorus mother liquor is a 15% potassium dihydrogen phosphate solution, and the potassium mother liquor is an 18% potassium sulfate solution, all stored in 316L stainless steel mother liquor tanks. The central controller, based on feedback from the EC sensor, controls the opening of the Burkert 6011 valve with linear adjustment from 0% to 100%. After passing through the Komax 340 mixer, the concentration deviation of the mixture is ≤3%; the spacing between the flow guide vanes is 50mm. The inner wall of the mixer is coated with a 0.2mm thick polyethylene coating, and flushed weekly with a 0.1% nitric acid solution for 10 minutes to prevent scaling. This embodiment effectively ensures that the ratio deviation of each element is <3%, improving mixing efficiency.

[0062] Example 4 Based on Example 1, the method further includes: soil nutrient monitoring units are evenly spaced at a soil depth of 15-25cm in the mulberry garden. Each monitoring unit integrates a conductivity sensor and a moisture sensor. Soil EC value and moisture content data are collected every 1 hour. The data are sent to the central controller through a low-power wireless transmission module. The central controller has a built-in irrigation decision algorithm.

[0063] Irrigation is activated when the measured soil electrical conductivity is more than 0.3 mS / cm lower than the preset value or the measured soil moisture content is less than 5% of the field capacity of the soil type. When applying rainfall deduction, the compensation coefficient K = 1 - 0.5 × (actual rainfall / 10 mm) and K ≥ 0.4.

[0064] A Venturi fertilizer applicator is installed 1.2 to 1.5 meters upstream of the turbine flow meter on the main pipeline, between the diameter expansion section and the rectifier grid. The Venturi fertilizer applicator is equipped with a vacuum maintenance device, including a 5L vacuum buffer tank and an electric vacuum pump connected in series. It automatically starts when the negative pressure at the suction inlet is lower than -0.075MPa, and maintains a working pressure of -0.075 to -0.085MPa.

[0065] When injecting liquid compound fertilizer mother liquor, a diameter expansion section is set upstream of the turbine flow meter to stabilize the local flow velocity at 2.3~2.7m / s.

[0066] Specifically, this implementation scheme uses a Decagon 5TE three-parameter soil sensor and a Jain 8032-VF self-priming venturi fertilizer applicator. During implementation, the Decagon 5TE sensor is buried 20cm deep and uploads EC values ​​(accuracy ±0.05mS / cm) and moisture content (±1%) to the central controller every 60 minutes. When the measured EC value is less than the preset value of 0.3mS / cm or the moisture content is less than 95% of field capacity, an irrigation command is triggered, with a rainfall deduction factor K = 1 - 0.5 × (actual rainfall / 10mm). The Jain 8032-VF fertilizer applicator is installed on the DN80 main pipeline, with an upstream diameter expansion section (DN100, length 1.2m) maintaining a flow rate of 2.5m / s. When the pressure in the vacuum buffer tank drops below -0.075MPa, an electric vacuum pump (Gast 0523 model) is activated to replenish the pressure. This implementation scheme reduces the irrigation decision response time to 15 minutes, significantly improving water savings.

[0067] Example 5 Based on Example 1, terrain adaptive compensation is also included: Execution of spray trajectory optimization algorithm: a) After the nozzle speed is increased in the high slope area, the spraying interval between adjacent nozzles is shortened by Δt = 0.12 × (α / 8°) seconds, where α is the tilt angle.

[0068] b) During the extended spraying time in low-lying areas, the nozzle elevation angle should be lowered by 3°~5° and the anti-drift mode should be activated.

[0069] The global pressure compensation value is calculated as P=0.5+0.025×(α-8)MPa, where α>8°.

[0070] Specifically, this implementation scheme uses a Nelson R33-A angle-adjusting nozzle for elevation adjustment. During implementation, an elevation map is generated using a laser terrain scanner (Leica ScanStation P40). Areas with a slope α > 8° are marked as high slope areas, and areas with α < 3° are marked as low slope areas. The nozzle rotation speed in high slope areas is increased to 3.2 rad / s (Δt = 0.12 × α / 8), while the nozzle elevation angle in low slope areas is adjusted to 25° (from 30°), and an anti-drift mode is activated (increasing the atomized particle diameter from 1.2 mm to 2.0 mm). The main pipeline pressure is adjusted according to the formula P = 0.5 + 0.025 × (α - 8) MPa; for example, the pressure is increased to 0.6 MPa when the slope is 12°. This implementation scheme significantly improves the uniformity of spraying on slopes.

[0071] Example 6 Based on Example 1, an anti-interference calibration module is also included for calibration: the spray coverage diameter is calibrated monthly using a laser rangefinder, with a maximum allowable deviation of ±0.15 meters; fertilizer penetration depth data from 10 sampling points are collected quarterly using a mobile soil tester to dynamically correct the mother liquor ratio parameters; the speed fluctuation of the variable frequency motor is controlled within ±3% of the set value.

[0072] Specifically, this implementation plan uses a Leica DISTO D510 laser rangefinder and a Hanna HI9814 soil analyzer for mobile monitoring. During implementation, the actual coverage diameter of the sprinkler heads is measured monthly using the Leica DISTO D510. If the deviation is >±0.15m, the sprinkler nozzle orifice diameter is adjusted. The Hanna HI9814 analyzer is used to collect 10 points in the mulberry orchard using a grid method. If the fertilizer penetration depth is <20cm, the mother liquor concentration is increased by 5%. The variable frequency motor speed is calibrated using a Fluke 754 calibrator; if the deviation is >±3%, the PID parameters are reset. This implementation plan extends the system calibration cycle and reduces maintenance costs.

[0073] Example 7 Based on Example 1, it also includes anti-clogging control, specifically including a four-level processing flow: The first-level processing is as follows: when the flow meter detects an instantaneous flow rate drop of 10%~15% that lasts for 30 seconds, the variable frequency motor speed is increased to 150% of the rated value for 5 seconds, and the pipeline pressure is maintained at 1.2 times the working pressure.

[0074] The secondary treatment is as follows: if the flow rate does not recover to 95% of the normal value within 60 seconds after the primary treatment, a 20Hz gas-liquid pulse wave impact is initiated. The pulse wave is generated alternately by 0.8MPa compressed air and 1.5MPa water flow, with 5 pulses per cycle, and is executed continuously for 3 cycles.

[0075] The third-level treatment is as follows: If the flow rate is still lower than 90% of the normal value within 120 seconds after the second-level treatment, switch to the backup pipeline and inject 0.1% citric acid solution, and circulate and flush for 10 minutes at a flow rate of 20L / min.

[0076] The fourth-level processing is as follows: when the blockage location signal originates from the mother liquor tank outlet, the filter screen is automatically switched to 80 mesh and a fault code is generated, and the backup mother liquor supply pipeline is started simultaneously.

[0077] Specifically, this implementation scheme uses a Flomatic G3-24 pulse valve assembly for the gas-liquid pulse generator. This scheme improves the blockage handling success rate to 92% and significantly reduces downtime.

[0078] Example 8 Based on Example 4, the method further includes: the EC value threshold setting specifically includes: setting it to 1.2~1.5mS / cm for the first 15 days of budding, and increasing it by 0.02mS / cm daily for the first 16~30 days; the EC threshold for the maturity period is dynamically adjusted according to the SPAD value of mulberry leaves: when the SPAD measured by the handheld chlorophyll meter is <42, it is set to 2.6mS / cm, and when SPAD is ≥42, it is set to 2.0mS / cm, and the sensor is calibrated every 48 hours.

[0079] Specifically, this implementation scheme uses a Konica Minolta SPAD-502Plus chlorophyll meter. This implementation scheme improves the stability of SPAD values.

[0080] Example 9 Based on Example 4, the method for precise application of water and fertilizer in mulberry garden sprinkler irrigation also includes: after irrigation, the water content distribution is detected by five soil moisture sensors distributed at the four corners and the center of the mulberry garden plot. The central controller compares the data of each sensor. When the difference in water content between any two monitoring points exceeds 3%, the geographical coordinates of the area with the largest difference are stored in the priority irrigation queue.

[0081] Specifically, this implementation scheme uses a Campbell Scientific CS655 multi-depth probe as the moisture sensor. During implementation, data from the Campbell CS655 sensor is read after irrigation, and the standard deviation σ is calculated. If the difference between two points is >3%, the coordinates of that area are marked, and the application rate to that area is increased by 10% during the next irrigation. This implementation scheme reduced the moisture distribution variation in the mulberry orchard from ±7% to ±2.5%.

[0082] Example 10 Based on Example 4, the method for precise application of water and fertilizer in mulberry garden sprinkler irrigation also includes: the central controller receives 24-hour rainfall data sent by the weather station every day. If the rainfall reaches 5mm, the preset irrigation schedule will be delayed by 24 hours. If the rainfall reaches 10mm, the irrigation water quota will be reduced by 50% of the rainfall in the next irrigation plan.

[0083] Specifically, the weather station used in this implementation plan is the Davis Vantage Pro2 wireless weather station. During implementation, the Davis Vantage Pro2 weather station sends rainfall forecasts daily at 08:00. If the predicted rainfall is ≥5mm, the irrigation plan is delayed by 24 hours; if the actual rainfall is ≥10mm, the system automatically deducts 50% of the irrigation amount. This plan improves water resource utilization by 30% and achieves a weather response accuracy of 92%.

[0084] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Further modifications can be readily implemented by those skilled in the art.

Claims

1. A method for precise application of water and fertilizer through sprinkler irrigation in mulberry orchards, characterized in that, include: Calculate the total amount of water and fertilizer sprayed by the nozzle based on the preset area covered by the nozzle and the amount of water and fertilizer applied per unit area. Based on the total amount of water and fertilizer applied by the nozzle, the total amount of water and fertilizer applied by the nozzle is adjusted in a timely manner through electronic metering switches and control systems. A pressure sensor is installed in the nozzle outlet pipeline to form a closed-loop control circuit with the frequency converter. The speed of the frequency converter motor is dynamically adjusted through the PID algorithm to keep the nozzle rotation angular velocity stable at 0.1~0.3 rad / s. Prepare stock solutions of different element fertilizers according to the preset fertilization requirements; Mother liquor and clean water are extracted in a set ratio using a water pump and a variable frequency motor; The variable frequency motor is controlled to precisely mix and apply fertilizers of different elements; It also includes a controller; the control logic of the controller and the variable frequency motor includes: dividing the nozzles into N control groups, the nozzle control group adopts a modular regional control architecture, each control module independently manages 3-5 nozzles, and adjacent control modules are connected by shielded twisted pair cables to form a ring communication network; each control module has a built-in main control unit and a backup control unit, the main control unit receives the reference speed command from the central controller in real time, and the backup control unit continuously monitors the working status of the main control unit, and seamlessly takes over control within 0.5 seconds when the main control unit fails; the speed adjustment of the variable frequency motor adopts a graded compensation mechanism: when the pressure sensor detects a pipeline pressure fluctuation ≤0.2MPa, the motor speed is finely adjusted through a PID algorithm, and the compensation range does not exceed ±2% of the set value; when the pressure fluctuation is >0.2MPa, it automatically switches to the preset pressure-speed compensation curve for coarse adjustment, and at the same time sends a pressure warning signal to the adjacent control module; It also includes terrain adaptive compensation: the spray trajectory optimization algorithm is executed as follows: a) After the nozzle speed is increased in high-slope areas, the spray interval between adjacent nozzles is shortened by Δt=0.12×(α / 8°) seconds, where α is the tilt angle; b) During the extended spraying time in low-lying areas, the nozzle elevation angle is reduced by 3°~5° and the anti-drift mode is activated; the global pressure compensation value is calculated as P=0.5+0.025×(α-8)MPa, where α>8°; areas with slope α>8° are marked as high-slope areas, and areas with α<3° are marked as low-lying areas; the atomized particle diameter in the drift mode is increased from 1.2mm to 2.0mm.

2. The method for precise application of water and fertilizer in mulberry orchards via sprinkler irrigation as described in claim 1, characterized in that, The preparation of the mother liquor specifically includes: Set up at least three mother liquor tanks in parallel to store nitrogen-based mother liquor, phosphorus-based mother liquor, and potassium-based mother liquor respectively. Each mother liquor tank is connected to a direct-acting solenoid valve with a valve opening accuracy of ±2%. The mother liquor and water are mixed through a three-way proportional valve. The opening ratio of each mother liquor valve is dynamically adjusted to ensure that the concentration of each element in the mixture deviates from the preset ratio by no more than 5%. The mixed solution flows through a static mixer with built-in 60° staggered guide vanes, the surface of which is coated with a polyethylene anti-adhesion coating.

3. The method for precise application of water and fertilizer in mulberry orchards via sprinkler irrigation as described in claim 1, characterized in that, Also includes: Soil nutrient monitoring units are evenly spaced at a soil depth of 15-25cm in the mulberry orchard. Each monitoring unit integrates a conductivity sensor and a moisture sensor. Soil EC value and moisture content data are collected every 1 hour. The data is sent to the central controller through a low-power wireless transmission module. The central controller has a built-in irrigation decision algorithm. Irrigation is activated when the measured soil electrical conductivity is more than 0.3 mS / cm lower than the preset value or the measured soil moisture content is less than 5% of the field capacity of the soil type. When applying rainfall deduction, the compensation coefficient K = 1 - 0.5 × (actual rainfall / 10 mm), K ≥ 0.

4. A Venturi fertilizer applicator is installed 1.2 to 1.5 meters upstream of the turbine flow meter on the main pipeline, between the diameter expansion section and the rectifier grid. The Venturi fertilizer applicator is equipped with a vacuum maintenance device, including a 5L vacuum buffer tank and an electric vacuum pump connected in series. It automatically starts when the negative pressure at the suction inlet is lower than -0.075MPa, and maintains a working pressure of -0.075 to -0.085MPa. When injecting liquid compound fertilizer mother liquor, a diameter expansion section is set upstream of the turbine flow meter to stabilize the local flow velocity at 2.3~2.7m / s.

4. The method for precise application of water and fertilizer in mulberry orchards via sprinkler irrigation as described in claim 1, characterized in that, Also includes: Configure the anti-interference calibration module for calibration: The spray coverage diameter is calibrated monthly using a laser rangefinder, with a maximum allowable deviation of ±0.15 meters. Every quarter, fertilizer penetration depth data are collected from 10 sampling points using a mobile soil testing instrument, and the mother liquor ratio parameters are dynamically adjusted. The speed fluctuation of the variable frequency motor is controlled within ±3% of the set value.

5. The method for precise application of water and fertilizer in mulberry orchards via sprinkler irrigation as described in claim 1, characterized in that, It also includes anti-clogging control, specifically comprising a four-level processing flow: The first-level processing is as follows: when the flow meter detects an instantaneous flow rate drop of 10%~15% that lasts for 30 seconds, the variable frequency motor speed is increased to 150% of the rated value for 5 seconds, and the pipeline pressure is maintained at 1.2 times the working pressure. The secondary treatment is as follows: if the flow rate does not recover to 95% of the normal value within 60 seconds after the primary treatment, a 20Hz gas-liquid pulse wave impact is initiated. The pulse wave is generated alternately by 0.8MPa compressed air and 1.5MPa water flow, with 5 pulses per cycle, and is executed continuously for 3 cycles. The third-level treatment is as follows: If the flow rate is still lower than 90% of the normal value within 120 seconds after the second-level treatment, switch to the backup pipeline and inject 0.1% citric acid solution, and circulate and flush for 10 minutes at a flow rate of 20L / min. The fourth-level processing is as follows: when the blockage location signal originates from the mother liquor tank outlet, the filter screen is automatically switched to 80 mesh and a fault code is generated, and the backup mother liquor supply pipeline is started simultaneously.

6. The method for precise application of water and fertilizer in mulberry orchards via sprinkler irrigation as described in claim 3, characterized in that, Also includes: After irrigation is completed, the water content distribution is detected by five soil moisture sensors distributed at the four corners and the center of the mulberry garden plot. The central controller compares the data of each sensor, and when the difference in water content between any two monitoring points exceeds 3%, the geographical coordinates of the area with the largest difference are stored in the priority irrigation queue.

7. The method for precise application of water and fertilizer in mulberry orchards via sprinkler irrigation as described in claim 3, characterized in that, Also includes: The central controller receives 24-hour rainfall data from the weather station daily. If the rainfall reaches 5mm, the preset irrigation schedule will be delayed by 24 hours. If the rainfall reaches 10mm, the irrigation water quota will be reduced by 50% of the rainfall in the next irrigation plan.