Multi-ecological synergistic water and fertilizer return liquid recycling system and method

Abstract

The invention relates to a multi-ecological synergistic water and fertilizer return liquid recycling system and method, and belongs to the technical field of automation and facility agriculture. The system comprises a clear water return liquid blending unit, a disinfection and sterilization unit, a fertilizer mother liquid switching unit, a fertilizer liquid blending unit and a multi-ecological fertilizer liquid irrigation unit; a system in the disinfection and sterilization unit can adjust the mixing ratio of the return liquid to the clear water: calculating a reasonable ratio of the clear water to the return liquid according to the acquired ultraviolet intensity and a set ultraviolet intensity rated value, and adjusting the ratio of the clear water to the return liquid through an electric double-channel valve. The UV sterilization technology and the direct irrigation type fertilizer applicator are integrated, and the problems that in return liquid containing iron and nickel ions, ultraviolet rays are difficult to penetrate, and sterilization is not thorough are successfully solved. Meanwhile, the design scheme of immediate treatment and immediate use avoids the problems of return liquid storage and secondary breeding of bacteria along with time. Efficient management of water and fertilizer integration is realized; the flexibility and efficiency of agricultural production are improved, and the production cost and the operation burden are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of automation and facility agriculture, and in particular to a multi-ecological synergistic and synergistic water-fertilizer liquid return recycling system and method. Background Art

[0002] In the existing fertilization and irrigation system, the return liquid fertilizer technology has attracted attention due to its resource recycling advantage. The existing fertilization and irrigation system faces a series of technical difficulties when introducing the return liquid fertilizer technology, especially the problem of residual iron and nickel ions in the return liquid. The residual iron and nickel ions in the return liquid have become a major obstacle to ultraviolet (UV) sterilization treatment. These ions significantly reduce the penetration of ultraviolet rays, which in turn affects the sterilization effect and seriously affects the sterilization efficiency of the return liquid. Traditional solutions such as reducing the flow gap and slowing down the water flow rate can enhance the ultraviolet radiation effect to a certain extent, but significantly reduce the sterilization efficiency; and the clean water dilution method in extreme cases can dilute the ion concentration, but it also brings about water resource waste and storage problems.

[0003] In addition, the mainstream return liquid treatment method - pre-sterilization and storage, has the risk of bacterial and viral regeneration during long-term storage. Although cyclic sterilization can deal with this problem, it increases energy consumption, time cost and operational burden. At the same time, the fertilization and irrigation system needs to be equipped with a fertilizer applicator and disinfection and sterilization equipment at the same time, which not only occupies a large space, has high energy consumption and a large initial investment, but also limits the flexibility and layout optimization of the agricultural operating environment.

[0004] Limitations of existing technologies: Space occupancy and energy consumption: The fertilization and irrigation system using liquid return needs to be equipped with a fertilizer applicator and a disinfection and sterilization unit at the same time, which occupies a lot of space and has high operating costs.

[0005] Initial investment and maintenance: The high cost of system purchase, installation and subsequent maintenance limits the widespread promotion of agricultural automation products.

[0006] Storage risk: Long-term storage of return liquid may cause the risk of microbial re-growth, affecting the use effect. Summary of the invention

[0007] The purpose of the present invention is to provide a multi-ecological synergistic water-fertilizer liquid return recycling system and method, that is, to highly integrate UV ultraviolet sterilization with a direct irrigation fertilizer applicator, thereby achieving efficient management of water and fertilizer integration to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions: A multi-ecological synergistic and effective water-fertilizer liquid recycling system and method, comprising: A clean water return liquid mixing unit, the clean water return liquid mixing unit comprises a plurality of clean water tanks, a plurality of return liquid tanks and return liquid delivery pipes respectively connected to the clean water tanks and the return liquid tanks and finally connected in parallel, valves are provided at the connection between the return liquid delivery pipes and the clean water tanks and the return liquid tanks, and an electric double-channel valve is installed at the parallel connection of the return liquid delivery pipes. When the system receives a trigger instruction for an irrigation task, the return liquid suitable for different crops is selected and switched according to preset requirements, and the clean water and return liquid are mixed according to the preset initial return liquid ratio, and the mixed liquid of the clean water and return liquid is circulated to ensure that the ratio of the mixed liquid meets the preset requirements; A disinfection and sterilization unit, the disinfection and sterilization unit comprises a UV disinfection and sterilization coil and an ultraviolet intensity detection sensor installed on the UV disinfection and sterilization coil, the UV disinfection and sterilization coil is connected to a return liquid delivery pipeline connected in parallel, when the mixed liquid of clean water and return liquid passes through the UV disinfection and sterilization coil, the ultraviolet intensity detection sensor monitors the light-transmitting ultraviolet intensity of the clean water and return liquid in real time, and compares it with a preset value, and according to the comparison result, the system adjusts the mixing ratio of the return liquid and the clean water; According to the collected UV intensity and the set UV intensity rating, the reasonable ratio of clean water and return liquid is calculated, and the ratio of clean water and return liquid is adjusted through the electric double-channel valve; When the UV intensity collection value is less than the intensity setting value, the controller increases the clean water and reduces the return liquid by adjusting the flow ratio of the electric two-channel valve; when the UV intensity collection value is greater than the intensity setting value, the controller reduces the clean water and increases the return liquid by adjusting the flow ratio of the electric two-channel valve; The adjustment target value of the electric dual-channel valve is: The adjustment target value is converted into a digital signal and sent to the controller. The controller makes corresponding adjustments to the ratio of the clean water and return liquid co-flow areas of the electric dual-channel valve. The system periodically collects and adjusts the electric dual-channel valve, links the adjustment of the radiation intensity and the clean water return liquid ratio, until the difference between the intensity collection value and the intensity setting value is less than or equal to the control dead zone, avoiding repeated adjustments of the system, ensuring that the ultraviolet intensity is always kept within the optimal sterilization range, and ensuring that microorganisms are effectively killed; A fertilizer mother liquid switching unit, the fertilizer mother liquid switching unit comprises a plurality of mother liquid tanks and mother liquid delivery pipes respectively connected to the mother liquid tanks, valves are provided at the connection between the mother liquid delivery pipes and the mother liquid tanks, and mother liquids suitable for different crops are selected and switched according to the preset requirements of the system; A fertilizer liquid mixing unit, the fertilizer liquid mixing unit comprises a control box, the controller is located in the control box, the control box is connected with the UV disinfection and sterilization coil and the mother liquid delivery pipeline, a fertilizer replenishment solenoid valve and an acid replenishment solenoid valve are respectively installed on the pipeline at the connection between the mother liquid delivery pipeline and the control box, the sterilized clean water and the return liquid mixed liquid and the mother liquid are mixed in the control box to form fertilizer liquid, the control box is provided with an EC sensor and a PH sensor to collect the EC value and PH value of the fertilizer liquid and adjust them through the fertilizer replenishment solenoid valve and the acid replenishment solenoid valve to meet the specific requirements of different crops for fertilizer nutrients and pH; A multi-ecological fertilizer liquid irrigation unit includes a plurality of irrigation pipes, which are connected to a control box. The precisely formulated fertilizer liquid will be accurately transported to the fields through the irrigation pipes to irrigate and fertilize the crops.

[0009] Preferably, the fertilizer liquid in the fertilizer liquid mixing unit is used as the target value for fertilizer replenishment, and the EC sensor is used as the feedback value for PID calculation, which is adjusted on the basis of the initial value of each set interval, and the duty cycle of the fertilizer suction solenoid valve is adjusted: The fertilizer solenoid valve fertilizer absorption duty cycle % = the initial percentage of the current setting value % + Kp × (EC sampling value - EC setting value) + Ki × ∫ (EC sampling value - EC setting value) dt + Kd × (EC sampling value - EC setting value) / dt.

[0010] Preferably, the fertilizer solution acid supplement in the fertilizer solution mixing unit takes the set value as the target value, and the pH sensor is used as the feedback value to perform PID calculation to adjust the initial value of each set interval, and adjust the duty cycle of the acid absorption solenoid valve: The acid absorption duty ratio of the acid replenishment solenoid valve % = the initial percentage of the current setting value % + Kp × (PH sampling value - PH setting value) + Ki × ∫ (PH sampling value - PH setting value) dt + Kd × (PH sampling value - PH setting value) / dt.

[0011] Preferably, the proportion of the return liquid adjusted in the clean water is in the range of 5-30%.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) Adjust the return liquid ratio to solve the problem of iron and nickel ions: Mix a certain proportion of return liquid into the clean water used to prepare the fertilizer solution, and flexibly adjust it according to the actual penetration effect of ultraviolet rays. This not only ensures the sterilization efficiency, but also avoids the waste of UV energy. While supplementing the elements required by crops, it effectively reduces the concentration of iron and nickel ions in the return liquid, improves the penetration ability of ultraviolet rays and the sterilization effect, and ensures the adequacy and thoroughness of sterilization.

[0013] (2) Precision fertilization improves efficiency: The system has built a multi-ecological circulation system, adjusted the fertilization and irrigation strategy according to crop needs, intelligently selected and switched the return liquid and mother liquid suitable for different crops, and configured the mother liquid in real time, ensuring the full utilization of fertilizers and reducing waste. It achieves precision fertilization and irrigation, and significantly improves the overall availability and efficiency of agricultural automated water-fertilizer return liquid circulation equipment.

[0014] (3) Space-saving and widely applicable: UV sterilization and direct irrigation multi-crop fertilizer applicator are highly integrated. While irrigating with fertilizer, the water source is mixed with return liquid and clean water and sterilized. It achieves seamless connection of functions. The highly integrated design greatly reduces space occupancy and can flexibly adapt to the needs of miniaturization and multiple ecosystems, providing efficient and convenient solutions for different agricultural production scenarios. It simplifies the operating process and ensures the precise application of water and fertilizer, thereby improving the flexibility and efficiency of agricultural production.

[0015] (4) Energy saving, emission reduction and cost reduction: The temporary storage barrel after traditional liquid return treatment is eliminated, which realizes practical application, reduces energy consumption and material consumption, and reduces the initial investment cost of equipment. Reducing initial investment, reducing energy consumption and material consumption will help reduce production costs and operating burdens, reduce farmers' labor intensity, open up new ways for the promotion and application of agricultural automation products, and provide strong support for the sustainable development of modern agriculture.

[0016] (5) Real-time application to avoid storage pollution: By realizing the immediate processing and application of the returned liquid, the present invention completely eliminates the risk of secondary pollution that may be caused by long-term storage, and ensures the hygiene and safety of the water-fertilizer circulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the multi-ecological integrated water-fertilizer liquid return circulation system and method of the present invention; Figure 2 The present invention is a flowchart of the multi-ecological integrated water-fertilizer liquid return circulation system and method.

[0018] Reference numerals 1. A fertilizer valve 1, 2. A fertilizer valve 2, 3. A fertilizer valve 3, 4. A fertilizer valve 4, 5. B fertilizer valve 1, 6. B fertilizer valve 2, 7. B fertilizer valve 3, 8. B fertilizer valve 4, 9. Acid replenishment solenoid valve, 10. Fertilizer replenishment solenoid valve 1, 11. Fertilizer replenishment solenoid valve 2, 12. Clean water valve 1, 13. Clean water valve 2, 14. Liquid return valve 1, 15. Liquid return valve 2, 16. Liquid return valve 3, 17. Liquid return valve 4, 18. Electric dual-channel valve, 19. Water pump, 20. Pre-collection EC sensor, 21. UV disinfection and sterilization coil, 22. Ultraviolet intensity detection sensor, 23. Control box, 24. Irrigation pipeline 1, 25. Irrigation pipeline 2, 26. Irrigation pipeline 3, 27. Irrigation pipeline 4. DETAILED DESCRIPTION

[0019] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0020] like Figure 1-2 As shown, a multi-ecological synergistic and efficient water-fertilizer liquid return recycling system and method includes: a clean water liquid return preparation unit, a disinfection and sterilization unit, a fertilizer mother liquid switching unit, a fertilizer liquid preparation unit and a multi-ecological fertilizer liquid irrigation unit.

[0021] The clean water return liquid mixing unit comprises two clean water tanks, four return liquid tanks and return liquid delivery pipelines respectively connected with each clean water tank and each return liquid tank and finally connected in parallel. The connection between the return liquid delivery pipeline and the two clean water tanks is provided with a clean water valve 12 and a clean water valve 2 13 respectively. The connection between the return liquid delivery pipeline and the four return liquid tanks is provided with a return liquid valve 14, a return liquid valve 2 15, a return liquid valve 3 16 and a return liquid valve 4 17 respectively. An electric double-channel valve 18 is installed at the parallel connection of the return liquid delivery pipeline to adjust the flow of clean water and return liquid. A water pump 19 is installed on the pipe at the connection between the road and the UV disinfection and sterilization coil 21 to provide power, and a pre-collection EC sensor 20 is installed on the pipe on one side of the water pump 19 to collect EC before the clean water and return liquid mixture are mixed with fertilizer; the clean water valve 12, the clean water valve 2 13, the return liquid valve 1 14, the return liquid valve 2 15, the return liquid valve 3 16, the return liquid valve 4 17, the electric dual-channel valve 18, the water pump 19 and the pre-collection EC sensor 20 are all electrically connected to the PLC controller in the control box 23.

[0022] When the system receives a trigger instruction for an irrigation task, it selects to open one of the return liquid valves 14, 15, 16 or 17 according to the preset requirements to meet the needs of different crops, and mixes the selected return liquid and clean water according to the set initial return liquid ratio, circulates the mixture of clean water and return liquid, and ensures that the ratio of the mixed liquid meets the preset requirements; the ratio of return liquid in clean water is adjusted in the range of 5-30%.

[0023] The disinfection and sterilization unit includes a UV disinfection and sterilization coil 21 and an ultraviolet intensity detection sensor 22 installed on the UV disinfection and sterilization coil 21. The UV disinfection and sterilization coil 21 is connected to the return liquid delivery pipeline in parallel. When the mixed liquid of clean water and return liquid passes through the UV disinfection and sterilization coil 21, the ultraviolet intensity detection sensor 22 monitors the light-transmitting ultraviolet intensity of the clean water and return liquid in real time, and compares it with a preset value. According to the comparison result, the system will adjust the mixing ratio of the return liquid and the clean water; the UV disinfection and sterilization coil 21 and the ultraviolet intensity detection sensor 22 are both electrically connected to the PLC controller in the control box 23.

[0024] According to the collected UV intensity and the set UV intensity rating, the reasonable ratio of clean water and return liquid is calculated, and the ratio of clean water and return liquid is adjusted through the electric double-channel valve; When the UV intensity collection value is less than the intensity setting value, the controller increases the clean water and reduces the return liquid by adjusting the flow ratio of the electric two-channel valve 18; when the UV intensity collection value is greater than the intensity setting value, the controller reduces the clean water and increases the return liquid by adjusting the flow ratio of the electric two-channel valve 18; The adjustment target value of the electric two-channel valve 18 is: The adjustment target value is converted into a digital signal and sent to the controller. The controller makes corresponding adjustments to the ratio of the clean water and return liquid co-flow areas of the electric two-channel valve 18, links the adjustment of the radiation intensity and the clean water return liquid ratio, and the system periodically collects and adjusts the electric two-channel valve until the difference between the intensity collection value and the intensity setting value is less than or equal to the control dead zone, avoiding repeated adjustments of the system, ensuring that the ultraviolet intensity is always kept within the optimal sterilization range, and ensuring that microorganisms are effectively killed; A fertilizer mother liquid switching unit, the fertilizer mother liquid switching unit comprises a plurality of mother liquid tanks and mother liquid conveying pipelines respectively connected to the mother liquid tanks, the mother liquid tanks are respectively four A fertilizer tanks, four B fertilizer tanks and one acid supplement tank, the mother liquid conveying pipeline is respectively provided with A fertilizer valve 1, A fertilizer valve 2, A fertilizer valve 3, and A fertilizer valve 4 at the connection with the four A fertilizer tanks, and is respectively provided with B fertilizer valve 1, B fertilizer valve 2, B fertilizer valve 3, and B fertilizer valve 4, 8 at the connection with the four B fertilizer tanks, the mother liquid conveying pipelines are respectively A fertilizer pipelines connecting the four A fertilizer tanks, B fertilizer pipelines connecting the four B fertilizer tanks and acid supplement pipelines connecting the acid supplement tank, a fertilizer supplement solenoid valve 10 is installed on the B fertilizer pipeline, a fertilizer supplement solenoid valve 2, 11 is installed on the A fertilizer pipeline, and an acid supplement solenoid valve 9 is installed on the acid supplement pipeline; the A fertilizer pipeline and the B fertilizer pipeline are arranged to avoid mixing of the AB fertilizer stock solutions, which will cause reaction and condensation, and condensation can be basically avoided after being mixed and diluted with clean water and return liquid; A fertilizer valve 1, A fertilizer valve 2, 2, A fertilizer valve 3, 3, A fertilizer valve 4, 4, B fertilizer valve 1, 5, B fertilizer valve 2, 6, B fertilizer valve 3, 7, B fertilizer valve 4, 8, fertilizer replenishment solenoid valve 1, 10, fertilizer replenishment solenoid valve 2, 11 and acid replenishment solenoid valve 9 are all electrically connected to the PLC controller in the control box 23.

[0025] According to the preset requirements of the system, select and switch the mother liquor suitable for different crops, select A fertilizer by opening one of A fertilizer valve 1, A fertilizer valve 2, A fertilizer valve 3, and A fertilizer valve 4, and select B fertilizer by opening one of B fertilizer valve 1, B fertilizer valve 2, B fertilizer valve 3, and B fertilizer valve 4, 8. Fertilizer A, fertilizer B and acid fertilizer are mixed to form a mother liquor to meet the needs of different crops.

[0026] The fertilizer liquid mixing unit includes a control box 23, in which a controller is located. The control box 23 is respectively connected with the UV disinfection and sterilization coil 21 and the A fertilizer pipeline, the B fertilizer tank and the acid supplement pipeline. The sterilized clean water and the mixed liquid of the return liquid and the A fertilizer, the B fertilizer and the acid fertilizer are mixed in the control box 23 to form a fertilizer liquid. The control box 23 is provided with an EC sensor and a PH sensor to collect the EC value and the PH value of the fertilizer liquid and adjust them through the fertilizer supplement solenoid valve 10, the fertilizer supplement solenoid valve 2 11 and the acid supplement solenoid valve 9 to meet the specific requirements of different crops for fertilizer nutrients and pH. In the fertilizer liquid mixing unit, the fertilizer replenishment takes the set value as the target value, and the EC sensor is used as the feedback value to perform PID calculation and make adjustments based on the initial value of each set interval, and adjust the duty ratio of the fertilizer replenishment solenoid valve 10 and the fertilizer replenishment solenoid valve 2 11: The fertilizer solenoid valve fertilizer absorption duty cycle % = the initial percentage of the current setting value % + Kp × (EC sampling value - EC setting value) + Ki × ∫ (EC sampling value - EC setting value) dt + Kd × (EC sampling value - EC setting value) / dt.

[0027] In the fertilizer liquid mixing unit, the fertilizer liquid acid supplement takes the set value as the target value, and the pH sensor is used as the feedback value to perform PID calculation to adjust the initial value of each set interval and adjust the duty cycle of the acid absorption solenoid valve: The acid absorption duty ratio of the acid replenishment solenoid valve % = the initial percentage of the current setting value % + Kp × (PH sampling value - PH setting value) + Ki × ∫ (PH sampling value - PH setting value) dt + Kd × (PH sampling value - PH setting value) / dt.

[0028] The multi-ecological fertilizer liquid irrigation unit includes irrigation pipe 1 24, irrigation pipe 2 25, irrigation pipe 3 26, and irrigation pipe 4 27. The four irrigation pipes are connected to the control box 23. The precisely adjusted fertilizer liquid will be accurately transported to the fields through the irrigation pipes to irrigate and fertilize the crops. The current irrigation time is recorded by the controller. When the current irrigation time is less than the set irrigation time, the system re-sends an irrigation signal to irrigate again. When the current irrigation time is greater than or equal to the set irrigation time, the irrigation is completed and the return liquid is collected.

[0029] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A multi-ecological synergistic water-fertilizer recycling system, characterized in that: include: A clean water return liquid mixing unit, the clean water return liquid mixing unit comprises a plurality of clean water tanks, a plurality of return liquid tanks and return liquid delivery pipelines respectively connected with the clean water tanks and the return liquid tanks and finally connected in parallel, valves are provided at the connection between the return liquid delivery pipeline and the clean water tanks and the return liquid tanks, and an electric double-channel valve is installed at the parallel connection of the return liquid delivery pipeline; A disinfection and sterilization unit, the disinfection and sterilization unit comprising a UV disinfection and sterilization coil and an ultraviolet intensity detection sensor installed on the UV disinfection and sterilization coil, the UV disinfection and sterilization coil being connected to a parallel return liquid delivery pipeline; A fertilizer mother liquid switching unit, the fertilizer mother liquid switching unit comprising a plurality of mother liquid tanks and mother liquid delivery pipelines respectively connected to the mother liquid tanks, wherein valves are provided at the connection between the mother liquid delivery pipelines and the mother liquid tanks; A fertilizer liquid mixing unit, the fertilizer liquid mixing unit comprises a control box, a controller is arranged in the control box, the control box is respectively connected with the UV disinfection and sterilization coil and the mother liquid delivery pipeline, a fertilizer replenishment solenoid valve and an acid replenishment solenoid valve are respectively installed on the pipeline at the connection between the mother liquid delivery pipeline and the control box, and an EC sensor and a PH sensor are arranged in the control box; A multi-ecological fertilizer liquid irrigation unit, wherein the multi-ecological fertilizer liquid irrigation unit comprises a plurality of irrigation pipes, and the irrigation pipes are connected to a control box.

2. The multi-ecological synergistic and synergistic water-fertilizer recycling method according to claim 1 is characterized in that: When the system receives the triggering instruction of the irrigation task, it selects and switches the return liquid suitable for different crops according to the preset requirements, and adjusts the initial return liquid ratio of clean water and return liquid, circulates the mixture of clean water and return liquid, and ensures that the ratio of the mixed liquid meets the preset requirements; When the mixture of clean water and return liquid passes through the UV disinfection and sterilization coil, the UV intensity detection sensor monitors the light transmittance UV intensity of the clean water and return liquid in real time, and compares it with the preset value. According to the comparison result, the system will adjust the mixing ratio of return liquid and clean water; According to the collected UV intensity and the set UV intensity rating, the reasonable ratio of clean water and return liquid is calculated, and the ratio of clean water and return liquid is adjusted through the electric double-channel valve; When the UV intensity collection value is less than the intensity setting value, the controller increases the clean water and reduces the return liquid by adjusting the flow ratio of the electric two-channel valve; when the UV intensity collection value is greater than the intensity setting value, the controller reduces the clean water and increases the return liquid by adjusting the flow ratio of the electric two-channel valve; The adjustment target value of the electric dual-channel valve is: The adjustment target value is converted into a digital signal and sent to the controller. The controller makes corresponding adjustments to the ratio of the clean water and return liquid co-flow areas of the electric dual-channel valve, links the adjustment of the radiation intensity and the clean water return liquid ratio, and the system periodically collects and adjusts the electric dual-channel valve until the difference between the intensity collection value and the intensity setting value is less than or equal to the control dead zone, avoiding repeated adjustments of the system, ensuring that the ultraviolet intensity is always kept within the optimal sterilization range, and ensuring that microorganisms are effectively killed; Select and switch mother liquid suitable for different crops according to system preset requirements; The sterilized clean water and return liquid mixture and the mother liquor are mixed in the control box to form fertilizer liquid. The EC sensor and pH sensor in the control box collect the EC value and pH value of the fertilizer liquid and adjust them through the fertilizer replenishment solenoid valve and acid replenishment solenoid valve to meet the specific needs of different crops for fertilizer nutrients and pH; The precisely formulated fertilizer liquid will be delivered accurately to the fields through irrigation pipes to irrigate and fertilize the crops.

3. The multi-ecological synergistic and synergistic water-fertilizer recycling method according to claim 2 is characterized in that: In the fertilizer liquid preparation, the set value is used as the target value for fertilizer replenishment, and the EC sensor is used as the feedback value for PID calculation. Adjustments are made based on the initial value of each set interval, and the duty cycle of the fertilizer suction solenoid valve is adjusted: The fertilizer solenoid valve fertilizer absorption duty cycle % = the initial percentage of the current setting value % + Kp × (EC sampling value - EC setting value) + Ki × ∫ (EC sampling value - EC setting value) dt + Kd × (EC sampling value - EC setting value) / dt.

4. The multi-ecological synergistic water-fertilizer recycling method according to claim 3 is characterized in that: In the fertilizer liquid preparation, the set value is used as the target value for acid supplementation of the fertilizer liquid, and the pH sensor is used as the feedback value for PID calculation. Adjustments are made based on the initial values ​​of each set interval, and the duty cycle of the acid absorption solenoid valve is adjusted: The acid absorption duty ratio of the acid replenishment solenoid valve % = the initial percentage of the current setting value % + Kp × (PH sampling value - PH setting value) + Ki × ∫ (PH sampling value - PH setting value) dt + Kd × (PH sampling value - PH setting value) / dt.

5. The multi-ecological synergistic and synergistic water-fertilizer recycling method according to claim 2 is characterized in that: The proportion of return liquid adjusted in clean water ranges from 5-30%.

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