Intelligent controllable farmland underground pipe earth surface-underground collaborative drainage system and method

Abstract

The invention discloses an intelligent controllable farmland underground pipe earth surface-underground collaborative drainage system and method, and relates to the field of farmland management. A surface runoff guide and drainage module of the system collects surface runoff of a rice-wheat rotation farmland; the underground water level regulation and control device is communicated with the underground concealed pipe drainage system and the tail water storage and reuse channel; the tail water storage and recycling channel is used for collecting surface runoff and tail water for irrigating farmland; the water level sensing network monitors the surface water depth and the underground water level in real time; the automatic control unit regulates and controls the water discharge amount of the surface runoff guide and drainage module, the water discharge amount of the underground concealed pipe drainage system, the height of the underground water level regulation and control device and / or the tail water storage and recycling channel according to the surface water depth and the underground water level which are monitored in real time; the surface water depth and / or the underground water level of the rice-wheat rotation farmland can meet the moisture demand parameters of the rice-wheat in each growth period. According to the method, accurate regulation and control of rice and wheat two-season moisture, cooperative treatment of waterlogging and waterlogging and resource recycling of drained water can be achieved, and the waterlogging and drought resistance of farmland is remarkably improved.

Description

Technical Field

[0001] This application relates to the field of farmland management, and in particular to an intelligent and controllable surface-subsurface coordinated drainage system and method for farmland underground pipe drainage. Background Technology

[0002] Underground drainage technology for farmland, which removes excess groundwater by burying permeable pipe networks, can effectively prevent waterlogging and regulate soil salinity, and is widely used in rice-wheat rotation areas. Rice-wheat rotation is a grain planting pattern, but there is a fundamental contradiction in the water management needs between the rice and wheat seasons: rice growth requires maintaining a certain water layer or a high soil moisture environment and the ability to retain rainwater; while wheat is susceptible to waterlogging and requires a rapid reduction of the groundwater level to maintain soil aeration.

[0003] Traditional farmland drainage systems mostly use open ditches or fixed-depth underground pipe systems, which have the following prominent problems: First, fixed-depth underground pipe drainage systems are difficult to adapt to the drastically different needs of rice and wheat seasons. During the wheat season, such systems can effectively control waterlogging, but during the rice season, they can cause excessive drainage, which not only increases irrigation costs but also leads to the loss of nutrients such as nitrogen and phosphorus, exacerbating agricultural non-point source pollution.

[0004] Secondly, existing systems lack the ability to precisely regulate groundwater levels based on crop growth stages. Rice exhibits significantly different sensitivities to groundwater levels at different growth stages (e.g., rapid water level reduction to 80cm is needed during the drying stage, while maintaining 60cm is required during the milk stage), but existing systems lack the ability to dynamically control thresholds in conjunction with the growth stages. Studies have shown that groundwater levels exceeding the threshold by 5cm for three consecutive days during the mid-tillering stage can lead to a yield reduction of up to 7.2%.

[0005] Furthermore, existing irrigation and drainage systems are fragmented and lack coordination. Most technologies focus only on underground or surface drainage, failing to address scenarios where surface waterlogging and underground waterlogging occur simultaneously after heavy rain. Meanwhile, direct discharge of wastewater leads to water waste, and existing wastewater reuse systems achieve less than 40% removal of dissolved pollutants, making it difficult to guarantee the quality of reused water.

[0006] In recent years, some improved technologies have been proposed, but they still have limitations: they do not address surface runoff regulation and adaptive switching between rice and wheat double-cropping, or they focus on intelligent drainage for saline-alkali land management, fail to resolve the water conflict in rice-wheat rotation, or only provide simulation devices for underground pipe design rather than real-time field control systems. Therefore, there is an urgent need for a comprehensive solution that integrates dynamic drainage, precise water control, intelligent decision-making, and wastewater purification to achieve the synergistic goals of water conservation, stable yield, and pollution reduction in rice-wheat rotation areas.

[0007] Farmland irrigation and drainage systems are crucial infrastructure for ensuring food production and sustainable agricultural development. Traditional irrigation and drainage methods largely operate with separate surface ditches and underground pipes, failing to address the diverse water and groundwater requirements of different crops in rice-wheat rotation systems. During the rice season, rice production emphasizes "shallow and frequent irrigation" and "rainwater storage and controlled irrigation" to improve rainfall utilization and reduce water consumption. However, existing irrigation methods generally lack precise control over irrigation depth, groundwater level, and rainwater storage capacity at different growth stages, often resulting in inefficient water management. This is detrimental to stable yields and water conservation, and can easily lead to nutrient loss with tailwater, exacerbating non-point source pollution in farmland. During the wheat season, wheat is a water-sensitive crop, requiring a suitable groundwater level to prevent waterlogging damage. However, existing underground drainage systems typically have fixed burial depths and single drainage intensities, unable to flexibly adjust according to rainfall intensity and crop water requirements. This leads to frequent waterlogging in rainy years, causing yield reduction and farmland ecological degradation.

[0008] In recent years, existing technologies have mostly focused on single water storage irrigation or single underground drainage, lacking a system design that organically combines irrigation, drainage and wastewater reuse.

[0009] Therefore, there is an urgent need for a system that can take into account the needs of rice-wheat rotation, achieve coordinated regulation of surface and groundwater drainage, have the ability to control groundwater levels in stages, and collect and reuse field tailwater, so as to improve the efficiency of agricultural water resource utilization, reduce non-point source pollution in farmland, and reduce the risk of waterlogging disasters. Summary of the Invention

[0010] The purpose of this application is to provide an intelligent and controllable surface-subsurface coordinated drainage system and method for farmland, which can realize precise water regulation for rice and wheat seasons, coordinated management of waterlogging and waterlogging, and resource reuse of drainage, significantly improving the ability of farmland to prevent waterlogging and resist drought.

[0011] To achieve the above objectives, this application provides the following solution: In one aspect, this application provides an intelligent and controllable surface-to-ground drainage system for farmland, comprising: a surface runoff guiding module, an underground drainage system, a groundwater level control device, a tailwater storage and reuse channel, a water level sensing network, and an automatic control unit. The surface runoff guiding module is installed on the surface of the rice-wheat rotation farmland and is used to collect surface runoff from the farmland. The underground drainage system is buried below the cultivated layer of the rice-wheat rotation farmland. The groundwater level control device is installed on the underground drainage system and connects to the underground drainage system and the tailwater storage and reuse channel. The tailwater storage and reuse channel is connected to both the surface runoff guiding module and the irrigation canal system of the rice-wheat rotation farmland. The tailwater storage and reuse channel collects surface runoff and tailwater from the underground drainage system and irrigates the farmland through the irrigation canal system. The water level sensing network is used to monitor the surface water depth and groundwater level of the rice-wheat rotation farmland in real time. The automatic control unit has built-in water requirement parameters for rice and wheat at each growth stage; the water requirement parameters include: upper limit of rainwater storage and target groundwater level.

[0012] The automatic control unit is used to monitor the surface water depth and groundwater level in rice-wheat rotation farmland in real time during the rice season. If the monitored surface water depth is greater than the rainwater storage limit, the surface runoff from the surface runoff diversion module is discharged to the tailwater storage and reuse ditch. If the monitored surface water depth is less than or equal to the rainwater storage limit, the monitored groundwater level is compared with the target groundwater level. When the monitored groundwater level is greater than the target groundwater level, the opening of the underground drainage valve and the height of the groundwater level control device in the underground pipe drainage system are adjusted to discharge groundwater to the tailwater storage and reuse ditch. When the monitored groundwater level is equal to the target groundwater level, the discharge of surface runoff and groundwater from the surface runoff diversion module is stopped, maintaining... Current situation: When the real-time monitored groundwater level is lower than the target groundwater level, the surface runoff and groundwater discharge from the surface runoff diversion module are stopped, and the tailwater storage and reuse channel is controlled to irrigate farmland through the irrigation canal system; the automatic control unit is also used to monitor the groundwater level of rice-wheat rotation farmland in real time during the wheat season; when the real-time monitored groundwater level is higher than the target groundwater level, the opening of the underground drainage valve and the height of the groundwater level control device in the underground pipe drainage system are adjusted so that the groundwater is discharged to the tailwater storage and reuse channel; when the real-time monitored groundwater level is equal to the target groundwater level, the current situation is maintained; when the real-time monitored groundwater level is lower than the target groundwater level, the tailwater storage and reuse channel is controlled to irrigate farmland through the irrigation canal system.

[0013] Secondly, this application provides an intelligent and controllable surface-to-subsurface coordinated drainage method for farmland underground pipes. This intelligent and controllable surface-to-subsurface coordinated drainage method is applied to the aforementioned intelligent and controllable surface-to-subsurface coordinated drainage system for farmland underground pipes. The intelligent and controllable surface-to-subsurface coordinated drainage method for farmland underground pipes includes: During the rice season, the surface water depth and groundwater level of rice-wheat rotation farmland are monitored in real time. If the real-time monitored surface water depth is greater than the rainwater storage limit, the surface runoff from the surface runoff diversion module is discharged to the tailwater storage and reuse channel. If the real-time monitored surface water depth is less than or equal to the rainwater storage limit, the real-time monitored groundwater level is compared with the target groundwater level. When the real-time monitored groundwater level is greater than the target groundwater level, the burial depth of the underground drainage system is adjusted to discharge groundwater to the tailwater storage and reuse channel. When the real-time monitored groundwater level is equal to the target groundwater level, the discharge of surface runoff and groundwater from the surface runoff diversion module is stopped, and the status quo is maintained. When the real-time monitored groundwater level is less than the target groundwater level, the discharge of surface runoff and groundwater from the surface runoff diversion module is stopped, and the tailwater storage and reuse channel is controlled to irrigate farmland through the irrigation canal system. During the wheat season, the groundwater level in rice-wheat rotation farmland is monitored in real time. When the real-time groundwater level is higher than the target groundwater level, the burial depth of the underground drainage system is adjusted so that the groundwater is discharged into the tailwater storage and reuse channel. When the real-time groundwater level is equal to the target groundwater level, the status quo is maintained. When the real-time groundwater level is lower than the target groundwater level, the tailwater storage and reuse channel is controlled to irrigate the farmland through the irrigation canal system.

[0014] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides an intelligent and controllable surface-underground coordinated drainage system and method for farmland. By adjusting the height of the groundwater level control device, the effective drainage depth of the underground pipe drainage system can be changed, enabling precise water control for both rice and wheat seasons. This adapts to the different water level requirements of rice and wheat in the two seasons, meets the water demand parameters of each growth stage of rice and wheat, and solves the problem of conflicting water requirements between the two crops in rice-wheat rotation areas. The automatic control unit can simultaneously regulate the drainage volume of the surface runoff guiding module and the drainage volume of the underground pipe drainage system, achieving coordinated surface and underground drainage to effectively cope with the dual disasters of waterlogging and flooding. The tailwater storage and reuse channel enables water resource recycling. In summary, this application significantly improves the waterlogging prevention and drought resistance capabilities of farmland. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A block diagram of an intelligent and controllable farmland underground pipe surface-subsurface coordinated drainage system provided in an embodiment of this application; Figure 2A schematic diagram of the intelligent and controllable farmland underground pipe surface-subsurface coordinated drainage system provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the drainage riser provided in the embodiments of this application; Figure 4 This is a schematic diagram of the design of an observation well provided in an embodiment of this application; Figure 5 This is a schematic diagram of the observation well outlet provided in an embodiment of this application; Figure 6 A schematic diagram of the installation of a controlled drainage device and a siphon device during the growth stage of rice and wheat provided in an embodiment of this application; Figure 7 This is a schematic diagram of the control process of the automatic control unit provided in the embodiments of this application; Figure 8 This is a schematic diagram of the automatic control unit predicting water level provided in an embodiment of this application.

[0017] Attached reference numerals: Underground pipe drainage system-1, Groundwater level control device-2, Tailwater storage and reuse ditch-3, Surface runoff guiding module-4, Automatic control unit-5, Underground pipe network-101, Control gate valve-102, Underground pipe outlet-103, Gradient section-104, Water collection well cover-105, Water collection well opening-106, Adjusting bend-201, Ring fastener-202, Anti-backflow fastener-203, Drainage pipe-204, Water pump-301, Drainage ditch-302, Plant filter media-303, Reclaimed water pump-304, Groundwater level sensor-601, Surface water level sensor-602, Water meter-7. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Chinese patent CN107268550A, entitled "An Adaptive Underground Pipe Drainage Control System," monitors plant root growth and groundwater levels to control the optimal water depth for plant growth, meeting plant needs while minimizing waterlogging damage. The system comprises an in-situ root scanner, an in-situ groundwater level sensor, a collection pipe and a storage tank, multiple underground pipes, and a controller. The in-situ root scanner acquires real-time data on crop root growth depth. The in-situ groundwater level sensor monitors dynamic changes in the field groundwater level. The collection pipe connects to the underground pipes, collecting drainage into the storage tank, which is connected to a pumping device. Multiple underground pipes are buried underground to remove excess water from the soil, each connected to the collection pipe. The controller is electrically connected to the in-situ root scanner, the in-situ groundwater level sensor, and the pumping device, receiving sensor data and outputting control commands to the pumping device.

[0021] Working Principle and Process: This system monitors crop root depth and groundwater level, and based on the optimal water requirements for crop growth, intelligently starts and stops the pumping device via a controller to regulate the groundwater level. Its core idea is to maintain the groundwater level at a suitable distance below the crop root layer, ensuring sufficient water for normal crop growth while preventing waterlogging. Data Acquisition: In-situ root scanners and groundwater level sensors continuously collect data on crop root depth and groundwater level. Decision Control: The controller's built-in algorithm calculates the target water level threshold based on crop type, growth stage (although a growth period model is not explicitly mentioned, it relies on root depth), and real-time monitored groundwater level. Drainage Execution: When the monitored groundwater level exceeds the target threshold, the controller activates the pumping device to drain water from the underground pipes to a storage tank, thereby lowering the field groundwater level; when the water level drops below the target threshold, pumping stops. Adaptive Regulation: The system dynamically adjusts the water level control target based on root growth, theoretically achieving adaptive drainage based on "root growth and water receding."

[0022] Advantages: It introduces the concept of root system monitoring, attempting to respond more accurately to crop water requirements; it realizes automatic control based on groundwater level feedback.

[0023] limitation: Lack of surface runoff regulation: The system only focuses on underground drainage and does not involve the monitoring and control of surface water accumulation or runoff, so it cannot cope with surface flooding caused by rainstorms.

[0024] Insufficient adaptability to rice-wheat rotation: Although it mentions adaptability to crop growth, it is not specifically designed for the drastically different water requirements of rice and wheat seasons (water storage and retention in the rice season and rapid drainage and waterlogging reduction in the wheat season), nor does it integrate functions such as rainfall forecasting.

[0025] Wastewater reuse mechanism: The collected wastewater (after flowing into the reservoir) is not considered for purification and reinjection, thus failing to achieve water resource recycling and non-point source pollution control.

[0026] The control factors are singular: they mainly rely on groundwater level and root depth, without fully considering soil moisture dynamics, meteorological conditions (such as rainfall forecasts), and the precise water requirement thresholds of different crop growth stages, thus limiting the comprehensiveness and foresight of the control strategy.

[0027] Chinese patent CN118581880A, entitled "Intelligent Underground Drainage System for Saline-Alkali Land Management," focuses on saline-alkali land management and features intelligent drainage control (such as monitoring EC values ​​and flow rates) and reverse flushing anti-clogging functions (such as a crystal removal robot). Limitations: Its core objective is "salt control" rather than "coordinated regulation of waterlogging," it does not address surface drainage management or adaptive water switching in rice-wheat rotation, and the system structure is complex and costly.

[0028] Chinese patent CN108951532A, entitled "Integrated Irrigation and Drainage Farmland Underground Pipe Simulation Device and Method for Determining Underground Pipe Combinations," focuses on optimizing underground pipe layout parameters (such as spacing and burial depth) through a physical simulation device to solve the problem of complex underground pipe design. Limitations: This is a simulation tool for the design phase, not an intelligent control system for real-time field operation. It cannot achieve dynamic water level management during crop growth, coordinated surface and underground drainage, or wastewater reuse.

[0029] Chinese patent application CN119145507A, entitled "Layered Drainage System for Construction Waste Slopes," targets urban construction waste slopes and incorporates both surface drainage structures (intercepting ditches and drainage ditches) and underground drainage structures (collection wells and underground water pipes) to achieve layered drainage. Limitations: Its application scenario is slope stabilization in civil engineering, not agricultural hydrological control. It lacks intelligent control elements for agriculture (such as crop water requirement sensing and automatic weir gate control) and does not involve irrigation coupling or water resource reuse.

[0030] In summary, the existing technologies mentioned above mostly focus on a single function or a specific scenario: Functional fragmentation: Some systems only control groundwater levels, some only drain surface water, and some only control salinity, lacking coordinated intelligent regulation based on multi-dimensional information from the surface, underground, crops, and meteorology.

[0031] Limitations of the scenario: It failed to effectively resolve the contradiction between seasonality and water management during the growing season caused by rice-wheat rotation.

[0032] Insufficient ecological benefits: The utilization of drainage resources and control of non-point source pollution are generally neglected, and there is a lack of closed-loop design for irrigation and drainage coupling.

[0033] In view of the above, this application provides an intelligent and controllable farmland underground pipe surface-subsurface coordinated drainage system that takes into account the needs of rice-wheat rotation, can realize coordinated regulation of surface and subsurface drainage, has the ability to control groundwater level in stages, and can collect and reuse field wastewater.

[0034] In one exemplary embodiment, such as Figure 1 As shown, a smart and controllable farmland underground pipe surface-underground coordinated drainage system is provided, including: a surface runoff guiding module 4, an underground pipe drainage system 1, a groundwater level control device 2, a tailwater storage and reuse ditch 3, and a water level sensing network ( Figure 2 (not explicitly marked in the text) and automatic control unit 5.

[0035] A surface runoff diversion module 4 is installed on the surface of the rice-wheat rotation farmland to collect surface runoff. An underground pipe drainage system 1 is buried below the cultivated layer of the rice-wheat rotation farmland. A groundwater level control device 2 is installed on the underground pipe drainage system 1, connecting it to the wastewater storage and reuse channel 3. The wastewater storage and reuse channel 3 is connected to both the surface runoff diversion module 4 and the irrigation canal system of the rice-wheat rotation farmland. The wastewater storage and reuse channel 3 collects surface runoff and wastewater from the underground pipe drainage system 1, and irrigates the farmland through the irrigation canal system.

[0036] A water level sensor network is used to monitor the surface water depth and groundwater level in rice-wheat rotation farmland in real time. The automatic control unit 5 has built-in water requirement parameters for each growth stage of rice and wheat; the water requirement parameters include: upper limit of rainwater storage and target groundwater level.

[0037] The automatic control unit 5 is used to monitor the surface water depth and groundwater level of rice-wheat rotation farmland in real time during the rice season. If the real-time monitored surface water depth is greater than the rainwater storage limit, the surface runoff from the surface runoff diversion module 4 is discharged to the tailwater storage and reuse ditch. If the real-time monitored surface water depth is less than or equal to the rainwater storage limit, the real-time monitored groundwater level is compared with the target groundwater level. When the real-time monitored groundwater level is greater than the target groundwater level, the opening of the underground drainage valve in the underground pipe drainage system 1 and the height of the groundwater level control device 2 are adjusted so that the groundwater is discharged to the tailwater storage and reuse ditch 3. When the real-time monitored groundwater level is equal to the target groundwater level, the discharge of surface runoff and groundwater from the surface runoff diversion module 4 is stopped, and the status quo is maintained. When the real-time monitored groundwater level is less than the target groundwater level, the discharge of surface runoff and groundwater from the surface runoff diversion module 4 is stopped, and the tailwater storage and reuse ditch 3 is controlled to irrigate the farmland through the irrigation canal system.

[0038] The automatic control unit 5 is also used to monitor the groundwater level of rice-wheat rotation farmland in real time during the wheat season; when the real-time monitored groundwater level is higher than the target groundwater level, it adjusts the opening of the underground drainage valve in the underground pipe drainage system 1 and the height of the groundwater level control device 2 so that the groundwater is discharged to the tailwater storage and reuse channel 3; when the real-time monitored groundwater level is equal to the target groundwater level, it maintains the status quo; when the real-time monitored groundwater level is lower than the target groundwater level, it controls the tailwater storage and reuse channel 3 to irrigate the farmland through the irrigation canal system.

[0039] Among them, the surface runoff drainage module 4 typically refers to the open ditches around and inside the field used to collect surface runoff. It should be consistent with... Figure 2 The system connects to drainage channels 302, which also collect surface water into tailwater storage and reuse channels 3 (also known as tailwater treatment systems). Underground pipe drainage system 1 is responsible for collecting and transporting groundwater. Groundwater level control device 2 utilizes the principle of communicating vessels to perfectly realize the function of "controlling groundwater levels at different depths by adjusting the height." Tailwater storage and reuse channels 3 realize a complete chain of drainage collection, purification, storage, and reuse. Automatic control unit 5 is an electronic control system that receives data from sensors such as water meters 7 and automatically controls the start and stop of various valves and pumps according to preset programs, achieving intelligent management. Automatic control unit 5 controls the opening and closing of groundwater level control device 2 and related valves based on preset upper and lower irrigation limits and rainwater storage limits for different growth stages of rice and wheat, achieving coordinated surface and underground drainage.

[0040] As an optional implementation, the surface runoff diversion module 4 includes a surface drainage ditch and a surface drainage gate. The surface drainage gate can be an electric lifting weir gate, which is set at the outlet of the field ridge.

[0041] As an optional implementation, the underground pipe drainage system 1 includes: a pipe network 101, a control gate valve 102, a transition section 104, and a collection well cover 105. The control gate valve 102 is installed on the pipe network 101; the narrow end of the transition section 104 is connected to the outlet end of the pipe network 101, and the wide end of the transition section 104 is connected to the groundwater level control device 2; the groundwater level control device 2 is installed inside the collection well cover 105.

[0042] The underground pipe network 101 forms an underground pipe system in the field, and the control gate valve 102 is a gate valve that controls the direction of water flow in the underground pipe. The transition section 104 connects to the outlet 103 of the underground pipe. The transition section 104 is mainly for the transition of diameter, flow velocity and flow rate, so as to achieve better metering and inverted siphon function.

[0043] As an optional implementation method, refer to Figure 2The groundwater level control device 2 includes: an adjusting bend 201, a drainage riser, multiple first drainage pipes, and multiple first drainage gate valves. One end of the adjusting bend 201 is connected to the outlet end of the underground culvert drainage system 1, and the other end of the adjusting bend 201 is connected to one end of the drainage riser. The drainage riser extends along the vertical depth direction underground, and its height is adjustable. Multiple first drainage pipes are installed at different heights of the drainage riser, and these multiple first drainage pipes are connected to the tailwater storage and reuse channel 3. A first drainage gate valve is installed on each first drainage pipe. Based on the principle of communicating vessels, the groundwater level at different depths is controlled by adjusting the height of the drainage riser.

[0044] like Figure 3 As shown, the drainage riser includes: a ring fastener 202 and an anti-backflow fastener 203. The adjusting bend 201 mainly serves a connecting function. Based on the principle of communicating vessels, when different groundwater levels are to be controlled, different sections of the ring fastener 202 (e.g., groundwater depths of 20cm, 40cm, and 60cm) are connected to achieve the control purpose. To prevent blockage, a water collection well cover 105 is installed over the pipe, and a water collection well opening 106 is provided for easy maintenance and operation. To connect with the tailwater storage and reuse channel 3, multiple first drainage pipes (drainage outlets for different groundwater depths) are installed, with gate valves to facilitate drainage control at different groundwater depths. To ensure that underground drainage can reach the channel, a water pump 301 is installed to pump water into the drainage channel 302 when needed.

[0045] As an alternative implementation, the groundwater level control device 2 includes: a telescopic sleeve, a controllable drainage valve, multiple second drainage pipes, and multiple second drainage gate valves. The multiple second drainage pipes are installed at different underground depths and are connected to the tailwater storage and reuse channel 3; one second drainage gate valve is installed on each second drainage pipe. One end of the telescopic sleeve is connected to the outlet end of the underground underground drainage system 1. By adjusting the height of the telescopic sleeve along the vertical depth direction, the other end of the telescopic sleeve is connected to the second drainage pipes at different depths, thus connecting the underground underground drainage system 1 with the tailwater storage and reuse channel 3.

[0046] Both the first and second drain pipes are Figure 2 Drainage pipe 204 in the middle.

[0047] Function of the telescopic sleeve: The telescopic sleeve is the core mechanical structure for adjusting the burial depth of underground pipes. By changing its own length, it raises or lowers the connected underground pipe section, thereby changing the effective drainage elevation of the entire underground pipe system. Installation location: It is installed in series on the branch pipe of the underground underground pipe drainage system 1. It is usually located in the middle section of the branch pipe or near the sump. Connection relationship: One end connects to the upstream underground pipe, and the other end connects to the downstream underground pipe or a controllable drainage valve. The telescopic sleeve's adjustment range covers the main water level depths required for both rice and wheat harvests.

[0048] The function of the controllable drain valve is to control the flow rate of drainage from the concealed pipe. When the valve is fully open, drainage is smooth and the water level drops quickly; when the valve is fully open, drainage is restricted, which helps maintain a higher water level. It works in conjunction with the expandable sleeve to achieve both "coarse adjustment" (burial depth) and "fine adjustment" (flow rate) of the water level. Installation location: It is usually installed on the outlet side of the expandable sleeve, i.e., at the end of the expansion joint structure. Connection relationship: Its inlet is directly connected to the outlet end of the expandable sleeve, and the outlet is connected to the pipe leading to the tailwater storage and reuse channel 3.

[0049] The expandable sleeve, controllable drain valve, and groundwater level sensor 601 in the water level sensing network together constitute an expansion joint. This expansion joint is a physical hydraulic expansion joint to change the overall burial depth of the underground pipe. The function of the groundwater level sensor 601 is to monitor the water level at the location of the expansion joint (i.e., the representative groundwater level of the area controlled by this branch pipe) in real time and transmit the water level signal to the automatic control unit 5, providing real-time feedback of position information to form a closed-loop control. Installation location: Installed inside the cavity of the expandable sleeve or in a dedicated pressure measuring pipe installed alongside it, ensuring that its sensing part accurately reflects the water pressure (water level) at that location. Connection relationship: Connected to the automatic control unit 5 via a signal line (such as a cable). It has a monitoring and controlled relationship with the expandable sleeve and controllable drain valve.

[0050] In summary: the expandable sleeve is responsible for changing the pipeline elevation, the controllable drain valve is responsible for regulating the pipeline flow, and the groundwater level sensor 601 (also known as a water level sensor) is responsible for monitoring the water level and providing feedback. These three components are integrated into a single functional unit—the expansion joint—which is connected in series with the branch pipe of the concealed pipeline.

[0051] The connection method between the expandable sleeve, controllable drain valve, and water level sensor and each branch pipe of the underground underground pipe drainage system 1 is as follows: a section of the branch pipe of the underground underground pipe drainage system 1 is cut off, and then the entire expansion joint is connected in series. Sealing flanges or socket rings are used at the connection points to ensure water tightness.

[0052] Burial Depth Adjustment Principle: The drainage capacity of a subsurface drainage system depends on the elevation of its pipe top (burial depth). Water naturally flows from higher to lower water levels. The function of the subsurface pipe is to provide a lower water level outlet. Adjustment Process: When groundwater level adjustment is needed, the automatic control unit 5 drives the telescopic sleeve. To lower the groundwater level: the telescopic sleeve extends, lowering the connected subsurface pipe section, thus reducing the outlet elevation of the entire subsurface system. This allows groundwater to flow to a lower outlet, thus lowering the field groundwater level. To raise the groundwater level: the telescopic sleeve shortens, raising the subsurface pipe section and increasing the subsurface outlet elevation. When the groundwater level is below this outlet, drainage stops, and the water level can naturally rise or be replenished through irrigation. Simply put, by adjusting the expansion joint, it's equivalent to moving the subsurface pipe's "drainage outlet" up and down, thereby controlling the field water level to remain stable near the "drainage outlet" elevation.

[0053] By adjusting the height of the telescopic sleeve and the opening of the drainage valve, precise control of groundwater levels at different depths can be achieved.

[0054] As an optional implementation, the tailwater storage and reuse channel 3 includes: a drainage channel 302, a pump 301, plant filter media 303, and a reuse water pump 304. The drainage channel 302 is connected to the surface runoff diversion module 4 and the groundwater level control device 2, respectively. The pump 301 is installed on the connecting pipe between the drainage channel 302 and the groundwater level control device 2. The pump 301 is used to pump groundwater through the underground pipe drainage system 1 and the groundwater level control device 2 to the drainage channel 302 when needed. Plant filter media 303 is laid inside the drainage channel 302 to purify the water inside the drainage channel 302. The drainage ditch 302 is connected to the irrigation canal system of the rice-wheat rotation farmland. A recycled water pump 304 is installed on the connecting pipeline between the drainage ditch 302 and the irrigation canal system of the rice-wheat rotation farmland. The recycled water pump 304 is used to pump the purified water inside the drainage ditch 302 back to the irrigation canal system to irrigate the rice-wheat rotation farmland.

[0055] To achieve wastewater reuse, drainage ditch 302 is lined with plant filter media 303, combined with constructed wetland technology, to achieve green purification. The wastewater is then pumped back to the field surface via a reuse pump 304. Wastewater storage and reuse ditch 3 is connected to the farmland irrigation system, allowing the collected wastewater to be reused for farmland irrigation, reducing water consumption and minimizing the loss of nutrients such as nitrogen and phosphorus from farmland. A simple sedimentation zone can be incorporated into drainage ditch 302 to improve the quality of reused water. Wastewater reuse involves guiding surface runoff and culvert wastewater into wastewater storage and reuse ditch 3, and then reusing the wastewater in farmland through the irrigation system, achieving efficient resource utilization.

[0056] As an optional implementation, the water level sensing network includes a groundwater level sensor 601 for monitoring the groundwater level in farmland and a surface water level sensor 602 for monitoring the depth of surface water accumulation. The groundwater level sensor 601 is installed in the groundwater level control device 2.

[0057] The groundwater level sensor 601 is vertically installed in an observation well inside the field. This observation well is a specially installed, permeable PVC or cement pipe, with a depth greater than the maximum possible burial depth of any underground pipe (e.g., 1.8 meters) to ensure accurate reflection of dynamic groundwater level fluctuations. Measurement target: Free groundwater level below the topsoil layer of farmland, i.e., the water level height above the top of the soil saturation zone.

[0058] The design of observation wells, such as Figure 4 As shown, the observation well outlet is as follows Figure 5 As shown. For Figure 4 Explanation: 1. The spacing between underground pipes is 15m, and the average burial depth is 1.0m. 2. The starting burial depth of the underground drainage pipe is 0.8m, and the outlet burial depth is 1.2m. The height needs to be strictly controlled, and elevation measurements should be continuously conducted. 3. The trench for laying the water collection pipes needs to maintain a certain slope, with a 20cm drop every 75m to ensure smooth drainage. 4. The observation wells need to be waterproofed inside and out. 5. The connecting pipes between wells are 160mm PE pipes. All water collection pipes enter the central observation well and are pumped out. Other water collection pipes are 90mm PE pipes.

[0059] This application's water level sensor employs an integrated magnetic ring switch control technology. The working principle of this technology is as follows: The water level sensor has a central rod containing a magnetostrictive wire. A float with a built-in permanent magnet is fitted around the rod and floats up and down with changes in water level. When measurement is needed, the electronic chamber generates a current pulse on the waveguide, producing a magnetic field that interacts with the magnetic field of the magnet inside the float, generating a torsional wave pulse. The propagation time of this pulse accurately determines the float's position (i.e., the water level). For switch control, a reed switch or other magnetic sensitive element can be installed at a preset position (corresponding to the upper / lower limit) inside the rod. When the float magnet reaches that position, it triggers the switch signal. Advantages: High precision, high reliability (no mechanical contacts, less prone to damage), fast response, and the ability to directly convert water level signals into electrical signals, making it ideal for connection with automatic control units (such as PLCs) for automated control. Its integrated design also facilitates installation and maintenance.

[0060] The automatic control unit 5 determines whether to start or shut down the underground drainage system 1 and how to adjust the height of the expansion joint by comparing the real-time monitored groundwater level with the preset target groundwater level thresholds for different growth stages of rice and wheat, thereby achieving precise water control.

[0061] As an alternative implementation method, since it is difficult to take readings and record data at a depth of about 1 meter underground, Figure 2 and Figure 4 The diagram also shows water meter 7, which can measure the drainage flow of each stage of the pipeline. For ease of maintenance, a longitudinal water meter 7 is connected to the electronic control system.

[0062] As an alternative implementation method, the design considers the potential for excessive drainage during the rice growing season and insufficient drainage during the wheat growing season after the underground pipe construction. To address these issues, drainage control devices are installed during the rice growing season, and siphon devices are installed during the wheat growing season, respectively. Figure 6 As shown. The height of the two devices can be adjusted according to demand and changes in outlet water level. For example, during the rice drying season, the drainage control device can be removed or even a siphon pipe can be installed to accelerate drainage. During the drought stage of wheat, it can also be replaced with a drainage control pipe.

[0063] Based on the above description of the system structure, the system mainly includes the following valves: I. Surface Runoff Drainage Module 4 Gate: Installed at the outlet or key control node of Surface Runoff Drainage Module 4. Opening Conditions: Rice Season: Opens for drainage when the real-time field surface water depth exceeds the rainwater storage limit to prevent flooding. Wheat / Rice Season (Non-Rainwater Storage Period): Opens immediately upon heavy rainfall to quickly drain surface water. Also opens when ditches need to be emptied. Closing Conditions: 1. Rice Season: Closes when the field surface water depth drops below the rainwater storage limit and water conservation is required. 2. Closes when drainage is completed and there is no threat of water accumulation in the field.

[0064] II. Controllable Drain Valve: As a component of the expansion joint, it is directly installed at the outlet end of the expandable sleeve. Opening Conditions: 1. Opens when the real-time groundwater level (H_current) is higher than the target control level (H_target). The greater the deviation, the larger the opening is usually to accelerate drainage. 2. Based on predictive control strategies, a certain opening degree is pre-opened before heavy rain to free up soil storage capacity. Closing Conditions: 1. Closes when the real-time groundwater level (H_current) reaches or falls below the target control level (H_target). 2. When water storage is required (e.g., during rice paddy irrigation), it is closed or maintained at a small opening even if the water level is slightly higher than the target.

[0065] III. Other optional features (please check for patent requirements): A tailwater reuse control valve, installed on the connecting pipe between the tailwater storage and reuse channel 3 and the irrigation canal system. When the system decides to utilize the purified tailwater stored in the channel for irrigation, it opens simultaneously with or before the reuse pump 304 starts. It closes when the irrigation task is completed and the reuse pump 304 stops.

[0066] Zonal control valves: These can be installed at the source of each branch pipe or on the main collection pipe of the underground drainage system 1. When independent drainage or irrigation of a specific area of ​​farmland is required, the valve corresponding to that area is opened. The valve is closed when the control task for that specific area is completed.

[0067] As an optional implementation method, rice and wheat growth stages include the greening stage, tillering stage, jointing and booting stage, heading and flowering stage, milk stage, and yellow ripening stage. During the rice season, the automatic control unit 5 automatically adjusts the surface runoff drainage module 4 (specifically, the surface drainage valve), the underground pipe drainage system 1, and the expansion joint according to a preset water control parameter table for different growth stages. This achieves precise control of the greening stage, tillering stage, jointing and booting stage, heading and flowering stage, milk stage, and yellow ripening stage. Specific irrigation upper limits and target groundwater levels are set for each stage, realizing "rainwater storage and controlled irrigation, and coordinated surface and underground drainage." During the wheat season, based on the wheat's water requirements and rainfall conditions, the drainage volume of the underground pipe drainage system is controlled by adjusting the height of the expansion joint, keeping the groundwater level within a preset range and at a suitable depth. This reduces the risk of waterlogging in rainy years and avoids the impact of waterlogging. The system dynamically adjusts the drainage depth based on the wheat root depth and soil characteristics.

[0068] like Figure 7 As shown, the water requirements parameters for rice and wheat at each growth stage include: upper limit of rainwater storage and target groundwater level. The control process of the automatic control unit 5 is as follows: Step 1: If the real-time monitored surface water depth is greater than the rainwater storage limit, open the surface drainage gate of the surface runoff diversion module 4 to discharge the surface runoff of the surface runoff diversion module 4 to the tailwater storage and reuse ditch 3.

[0069] Step 2: If the real-time monitored surface water depth is less than or equal to the rainwater storage limit, then compare the real-time monitored groundwater level with the target groundwater level.

[0070] Step 3: When the real-time monitored groundwater level is higher than the target groundwater level, adjust the opening of the underground drainage valve in the underground pipe drainage system 1 and the height of the groundwater level control device 2 to discharge the groundwater into the tailwater storage and reuse ditch 3.

[0071] Step 4: When the real-time monitored groundwater level is equal to the target groundwater level, close the surface drainage gate and the underground drainage valve to maintain the status quo.

[0072] Step 5: When the real-time monitored groundwater level is lower than the target groundwater level, close the surface drainage gate and the underground drainage valve, and control the tailwater storage and reuse ditch 3 to irrigate farmland through the irrigation canal system.

[0073] For example, during the mid-tillering stage of rice, the groundwater level is required to be controlled at 60 cm below the field surface. This target groundwater level (H_target) is the benchmark for regulation. Real-time feedback: Water level sensor reading: The system reads the current groundwater level (H_current) in real time.

[0074] Control algorithm: Height adjustment of the telescopic casing (coarse adjustment): Its target position is preset according to the crop type and growth stage. For example, the burial depth is default set to 1.2 meters in the wheat season and 0.8 meters in the tillering stage of the rice season. This setting is relatively fixed and does not change frequently unless the season or stage is switched. Opening adjustment of the controllable drainage valve (fine adjustment): This is the key to achieving precise control. The opening size is dynamically adjusted according to the deviation (ΔH) between the current water level (H_current) and the target water level (H_target). ΔH is large (such as the water level is far above the target): The valve is fully open for rapid drainage. ΔH is small (such as the water level fluctuates near the target value): The valve is opened with a small opening or intermittently for fine control to prevent the water level from dropping excessively. ΔH is negative (the water level is below the target): The valve is closed to stop drainage and store the water level.

[0075] Summary: The height of the casing is preset according to "season and growth period" to achieve water level control at different depths; the opening of the valve is dynamically fine-tuned according to the "deviation between the real-time water level and the target water level" to achieve precise and stable control.

[0076] As another alternative implementation, the water demand parameters for each growth stage of rice and wheat include: upper limit of rainwater storage, upper limit of irrigation, and lower limit of irrigation. The core logic of irrigation control is: The system determines whether irrigation is needed by monitoring the depth of the surface water layer (for rice) or the soil moisture content (for wheat), and compares it with the preset upper and lower limits to decide whether to start irrigation. Upper limit of irrigation (H_upper_limit): 30 mm (the upper limit of the ideal water layer depth), lower limit of irrigation (H_lower_limit): 5 mm (the lower limit of the water layer depth triggering irrigation). The control process is as follows: Real-time monitoring: The surface water level sensor 602 continuously monitors the depth of the water layer on the field surface (H_current).

[0077] Decision-making judgment: If H_current > H_upper_limit (that is, the water layer exceeds 30 mm), it means there is too much water and no irrigation is needed, and the system may consider starting drainage. If H_lower_limit < H_current <= H_upper_limit (that is, the water layer is between 5 mm and 30 mm), it means the moisture is appropriate and no irrigation is needed. If H_current <= H_lower_limit (that is, the water layer drops to 5 mm or below), it means irrigation is needed, and the automatic control unit 5 issues an instruction to start irrigation.

[0078] Irrigation is performed: The irrigation system (such as water pumps and solenoid valves) is activated to supply water to the fields.

[0079] Stop irrigation: When real-time monitoring shows that H_current reaches or approaches H_upper_limit (e.g., reaches 28mm-30mm), the automatic control unit 5 issues a command to stop irrigation.

[0080] For the early / mid tillering stage (with field capacity as the lower limit): the control logic is similar, but the monitoring object changes from "surface water layer depth" to "soil volumetric water content". A lower limit of 75% of field capacity means that when the sensor detects soil moisture content below 75% of field capacity, the system triggers irrigation until the water is replenished to a suitable level.

[0081] In summary, the upper and lower limits of irrigation together define a "suitable water range". The system automatically decides to start or stop irrigation by comparing real-time monitoring values ​​with this range, thus achieving precise water supply.

[0082] As an optional implementation, the automatic control unit 5 is used to collect historical rainfall data and corresponding water levels under different meteorological conditions; the water level is either field water depth or groundwater level; based on the historical rainfall data and corresponding water levels under different meteorological conditions, a machine learning model is trained to obtain a water level prediction model; rainfall data from meteorological forecasts is acquired and input into the water level prediction model to predict future water levels; when it is the rice season, the future water level is compared with the allowable flooding depth for each growth stage of rice; if the future water level is greater than the allowable flooding depth for each growth stage of rice, an early warning is issued; when it is the wheat season, the future water level is compared with the maximum allowable groundwater level for the wheat season; if the future water level is greater than the maximum allowable groundwater level for the wheat season, an early warning is issued.

[0083] like Figure 8 As shown, the more specific implementation process is as follows: collect historical short-term heavy rainfall data; construct the relationship between historical rainfall and waterlogging indicators; train the model using machine learning methods and rainstorm disasters under different meteorological conditions; obtain multivariate short-term forecast rainfall data, and use the trained model to predict future field water depth or groundwater level; compare with the allowable flooding depth for each growth stage of rice and the maximum allowable groundwater level for wheat season; if the predicted value exceeds the allowable value, issue an early warning; if the predicted value does not exceed the allowable value, return to the step of "obtaining multivariate short-term forecast rainfall data".

[0084] As an optional implementation, the automatic control unit 5 is used to access weather forecast data. When the weather forecast data includes heavy rain, the burial depth of the underground drainage system 1 is adjusted before the heavy rain arrives, so that groundwater is discharged into the tailwater storage and reuse channel 3, thus lowering the groundwater level in advance. Therefore, the automatic control unit 5 monitors the farmland water level and rainfall in real time through the water level sensor and the automatic control unit 5, and automatically adjusts the irrigation and drainage status according to preset parameters to achieve integrated irrigation and drainage management.

[0085] The working principle of this system is as follows: Expansion joints alter the effective drainage depth of the underground pipe system to adapt to the different water level requirements of the rice and wheat seasons. During the rice season, the system maintains suitable groundwater levels and surface water layers by controlling the height of the expansion joints and the opening of valves, based on water demand parameters at each growth stage, thus achieving rainwater harvesting and controlled irrigation. During the wheat season, the drainage depth is adjusted to rapidly lower the groundwater level and prevent waterlogging. The surface runoff diversion module 4 works in conjunction with the underground pipe system, achieving intelligent management through the automatic control unit 5. The wastewater recycling system collects and purifies the wastewater before reusing it for irrigation, forming a closed-loop system for water resource recycling.

[0086] Compared with existing technologies, this application solves the problem of conflicting water requirements between rice and wheat rotation areas. It achieves dual-use of a single system through adjustable drainage depth; it realizes precise water management based on crop growth stages, improving water resource utilization efficiency; it coordinates surface and underground drainage to effectively cope with the dual disasters of waterlogging and flooding; the tailwater reuse system reduces water waste and non-point source pollution; automated intelligent control reduces management costs and improves system response speed; the system has a reasonable structure, strong applicability, and can be implemented by modifying existing farmland drainage systems.

[0087] The feasibility of this application system is illustrated below with a specific implementation case.

[0088] The system described in this application was deployed in a rice-wheat rotation area, covering a field area of ​​approximately 5 mu (about 0.33 hectares). Surface runoff drainage modules 4 were installed around the perimeter and in the center of the farmland, with a ditch depth of 30 cm, a bottom width of 20 cm, and a slope ratio of 1:1, for collecting surface runoff. Underground pipe drainage system 1 was buried below the cultivated layer, using 80 mm diameter PVC corrugated permeable pipes. The burial depth could be adjusted according to the season, with pipe spacing of 15 m and a slope of 0.3%. It was connected to the surface runoff drainage modules 4 via vertical connection wells.

[0089] Expansion joints are installed on each branch pipe of the underground drainage system 1, and include a telescopic sleeve, a controllable drain valve, and a water level sensor. The telescopic sleeve is made of stainless steel corrugated pipe and its height can be adjusted within the range of 80cm-150cm via a hydraulic device, with an accuracy of ±2cm. The controllable drain valve is an electric ball valve, and its opening degree can be precisely controlled. The water level sensor is a pressure-type water level sensor that monitors changes in the groundwater level in real time.

[0090] Tailwater storage and reuse channel 3 is located downstream of the field, with a depth of 1.2m, a width of 1.5m, and a length of 20m, and includes a simple sedimentation area. The channel is connected to the surface runoff diversion module 4 and the underground culvert drainage system 1 via pipelines, and at its end, it is connected to the irrigation canal system via a lift pump to achieve tailwater reuse.

[0091] The automatic control unit 5 uses a PLC-based controller and has a built-in database of water regulation parameters for rice and wheat growth stages, including specific parameters for each stage such as the greening stage, tillering stage, jointing and booting stage, heading and flowering stage, milk stage, and yellow ripening stage. During the greening period: irrigation limit 30mm, irrigation limit 5mm, rainwater storage limit 50mm; Early tillering stage: irrigation limit of 30mm, irrigation limit of 75% of field capacity, and rainwater storage limit of 100mm; Mid-tillering stage: irrigation limit of 30mm, irrigation limit of 70% of field capacity, and rainwater storage limit of 120mm.

[0092] The system monitors the surface water depth and groundwater level in real time through multiple water level sensors deployed in the field. The automatic control unit 5 controls the height adjustment of the expansion joint and the opening and closing of related valves based on the crop growth stage and real-time monitoring data.

[0093] Work process: During the mid-tillering stage of the rice season, in the event of rainfall, the automatic control unit 5, based on the preset maximum rainfall storage parameter of 120mm, controls the gate portion of the surface runoff drainage module 4 to close, while simultaneously adjusting the expansion joint to maintain the burial depth of the underground pipe at 100cm, thus achieving the rainwater storage function. When the rainfall stops, if the groundwater level exceeds the set value of 65cm, the system automatically opens the underground pipe to drain excess water into the tailwater storage and reuse ditch 3.

[0094] During the wintering period of wheat harvest, if continuous rainfall is forecast according to weather forecasts, the automatic control unit 5 adjusts the expansion joint in advance to reduce the burial depth of the underground pipe to 120cm and opens the drainage valve to quickly reduce the groundwater level to a suitable depth of 80cm or less to prevent waterlogging.

[0095] The wastewater collected in the tailwater storage and reuse channel 3 is settled and then reused for farmland irrigation through an irrigation pumping station, thus realizing the recycling of water resources.

[0096] This embodiment demonstrates that the system of this application can effectively adapt to different needs of rice-wheat rotation, achieve precise water management and drainage resource utilization, improve water resource utilization efficiency, reduce non-point source pollution, and has good application prospects.

[0097] Existing adaptive underground drainage control systems (represented by Chinese patent publication number CN107268550A) primarily achieve groundwater level control by monitoring root depth and groundwater level. However, because this system only focuses on underground drainage and its control strategy is not deeply coupled with the water requirements of crop growth stages and meteorological conditions, it has fundamental shortcomings in addressing the complex needs of rice-wheat rotation.

[0098] The most significant drawback is the lack of a coordinated control mechanism for surface runoff and groundwater drainage, making it unable to simultaneously address the dual disasters of waterlogging and flooding. This is because: Causal Chain 1: The system lacks surface water level monitoring devices and controllable surface drainage structures (such as retractable weirs) → resulting in the inability to effectively intercept and guide surface runoff during heavy rains → causing surface water accumulation and flooding, which, combined with groundwater damage, severely damages crops. Causal Chain 2: The control logic relies solely on groundwater levels and root depth, without incorporating crop growth period water thresholds and rainfall predictions → preventing the proactive closure of drainage during the rice season when rainwater storage is needed, and the premature activation during the wheat season when pre-drainage is required → leading to water waste or increased risk of flooding.

[0099] Secondary disadvantages: Functional limitation: Since the initial design purpose of the system was only for drainage and flood prevention, without considering the resource utilization of drainage, it resulted in the direct discharge of nutrient-rich farmland drainage, which exacerbated non-point source pollution and wasted water resources.

[0100] Insufficient adaptability: Due to its reliance on complex sensors such as in-situ root scanners, the system is costly and complex to maintain, making it difficult to promote and popularize in large-scale farmland.

[0101] Strategy lag: Because control is based on real-time monitoring rather than prediction, the system response always lags behind weather changes, resulting in limited adjustment capabilities in the face of sudden rainstorms.

[0102] Therefore, this application proposes a coupled intelligent control system for irrigation and drainage in rice-wheat rotation. By constructing a physical architecture of "expandable underground pipes - ditch purification" and integrating a control core of "growth period model - rainfall prediction - intelligent algorithm," it achieves the integrated goals of coordinated surface and underground drainage, combined flood control and waterlogging management, water conservation and pollution reduction, and stable yield and increased efficiency. Specifically: The main drawback was addressed by adding a surface water level sensor 602 and linking it with the underground pipe for control, which enabled the synchronous and efficient discharge and storage of surface runoff and groundwater, fundamentally solving the problem of coexistence of waterlogging and flooding.

[0103] Addressing minor drawbacks: By adding a channel water purification module (sedimentation tank + biological filter dam) and a 304 recycled water pump, wastewater purification and resource reuse were achieved, realizing water conservation and pollution reduction. Replacing the expensive root scanner with a reliable and relatively low-cost water level sensor and a weather forecast-based algorithm improved the system's economy and feasibility for widespread adoption while maintaining functionality. Integrating a rainfall prediction module enabled forecast-based pre-discharge and pre-drainage control, overcoming the lag in response of traditional systems.

[0104] The significant advancements of this application are as follows: 1. It has solved the core shortcoming of "lack of coordinated regulation between surface and underground" and achieved "comprehensive management of waterlogging and soil erosion".

[0105] Reasoning process: Because existing technologies (such as Chinese Patent No. CN107268550A) only focus on underground drainage, they are unable to cope with surface flooding. Therefore, this application innovatively integrates the surface runoff diversion module 4 with the underground pipe drainage system 1, and performs unified scheduling through the automatic control unit 5.

[0106] Advantages: It enables coordinated management of surface runoff and groundwater. During heavy rain, the system can simultaneously activate surface drainage and accelerate groundwater drainage, quickly eliminating the dual threats of waterlogging. When rainwater storage is needed during the rice season, drainage facilities can be shut off and surface ditches can be used to store water, fundamentally solving the problem that a single drainage method cannot address waterlogging.

[0107] 2. It solves the shortcoming of "the control strategy is not coupled with the crop growth period and weather", and realizes "precise on-demand regulation".

[0108] Reasoning process: Due to the simple and lagging control logic of existing systems, water resources are wasted or crops are damaged. Therefore, this application incorporates the research results of preset upper and lower limits for irrigation and upper limits for rainwater storage at different growth stages of rice and wheat as the core of the control system.

[0109] Advantages: It enables refined management based on the physiological water requirements of crops. The system can automatically identify the growth stage (such as the tillering stage or the field drying stage) and call the corresponding water parameters (such as the upper limit of rainwater storage of 120mm during the tillering stage) to control the actuators, ensuring that water regulation is always in the most suitable state for crops, thereby effectively saving water and promoting high and stable crop yields.

[0110] 3. It has solved the shortcomings of "single function and lack of drainage reuse mechanism" and achieved "water saving and pollution reduction".

[0111] Reasoning: Existing technologies only focus on drainage, leading to resource waste and non-point source pollution. Therefore, this application adds a tailwater storage and reuse channel 3 and connects it to the irrigation canal system.

[0112] Advantages: It forms a closed-loop system for the resource utilization of drainage. Nutrient-rich farmland drainage is no longer directly discharged into the environment, but is collected, stored, and reused for irrigation. This not only saves irrigation water, but also significantly reduces the emission of non-point source pollutants such as nitrogen and phosphorus, achieving a win-win situation for both economic and ecological benefits.

[0113] 4. It solves the shortcomings of "reliance on expensive sensors and difficulty in promotion", and improves "economic efficiency and universality".

[0114] Reasoning: Similar technical solutions rely on expensive equipment such as in-situ root scanners, resulting in high costs and difficulty in widespread adoption. Therefore, this application uses reliable and relatively low-cost sensing elements such as water level sensors, combined with algorithms based on reproductive period models, to achieve precise control.

[0115] The advantages are: while ensuring intelligence and accuracy, the manufacturing cost and maintenance complexity of the system are significantly reduced. This makes this application easier to promote and apply in large-scale farmland, and it is especially suitable for the construction of high-standard farmland under my country's national conditions.

[0116] 5. It has solved the problem of "delayed response" and enhanced the "ability to cope with sudden weather events".

[0117] Reasoning: Because existing systems rely on real-time monitoring, their response is always slower than weather changes. Therefore, the automatic control unit 5 of this application can access meteorological data and perform pre-control based on forecasts before heavy rain arrives.

[0118] Advantages include predictive and proactive control capabilities. For example, the system can pre-lower the groundwater level before heavy rain based on weather forecasts, creating water storage capacity for the soil and thus greatly improving the ability to cope with extreme rainfall events and mitigating disaster losses.

[0119] In summary, this application, through the deep integration of "structural innovation" (expansion joint + collaborative drainage architecture) and "control logic innovation" (fertility period model + dual-mode switching), systematically and specifically addresses many shortcomings of existing technologies, ultimately achieving comprehensive advantages such as flood control, water conservation and pollution reduction, energy saving and cost reduction, and stable production and increased efficiency. It provides a complete intelligent solution for farmland water resource management in rice-wheat rotation areas.

[0120] To achieve the core invention objective of "adaptive drainage regulation for double-cropping rice and wheat, combined with flood control and water conservation and pollution reduction," some technical modules can be replaced as follows, while retaining the same inventive concept: 1. Alternative solution for groundwater level regulation module Original plan: Use physical hydraulic expansion joints to change the overall burial depth of the concealed pipe.

[0121] Alternative Solution 1 (Electric Actuator Solution): An electric linear actuator replaces the hydraulic drive mechanism. One end of the actuator is fixed to the fulcrum of the buried pipe, and the other end is connected to the pipe section. The central controller sends commands to control the extension and retraction of the actuator, allowing for precise adjustment of the elevation of specific sections of the buried pipe to achieve changes in burial depth. Advantages: Eliminates the hydraulic circuit, simplifying maintenance. Disadvantages: Potentially lower thrust; less stable than hydraulic systems in environments with high soil resistance.

[0122] Alternative Solution Two (Segmented Valve Control): This solution maintains the fixed burial depth of the concealed pipes. Instead, multiple independent concealed pipe subsystems are installed in parallel at different burial depths (e.g., 0.8m, 1.0m, 1.2m), each equipped with an independent electric valve. The equivalent "drainage depth" can be adjusted by opening and closing the valves at different burial depths through a central controller. Advantages: Simple structure, no moving parts, high reliability. Disadvantages: Larger workload and initial investment.

[0123] 2. Alternative solutions for surface runoff regulation modules Original plan: Install an electric lifting weir gate at the exit of the field ridge.

[0124] Alternative solution (forced drainage with pumps): Set up collection wells in low-lying areas of the field, each equipped with a level sensor and a drainage pump. When the central controller determines that accelerated surface drainage is needed (e.g., after heavy rain), the pumps are activated to forcefully drain the accumulated water into the ditches. Advantages: High drainage efficiency, unaffected by external ditches' water levels. Disadvantages: Requires additional energy, resulting in higher operating costs.

[0125] 3. Alternative solutions for information sensing modules Original solution: Relies on contact groundwater level sensor 601 and soil moisture sensor.

[0126] Alternative solutions (non-contact / remote sensing): Utilize field camera image recognition technology to determine surface water depth; or use spaceborne / airborne remote sensing data to retrieve regional soil moisture conditions as a supplementary input to the control system. Advantages: Wide-area monitoring, reduced field cabling. Disadvantages: Susceptible to weather conditions; accuracy and real-time performance may be slightly inferior to contact sensors.

[0127] 4. Alternative solutions for effluent purification modules Original plan: Adopt a cascaded natural purification process of "vortex sedimentation tank + biological filter dam".

[0128] Alternative Option 1 (Constructed Wetland Solution): Wastewater is introduced into a small constructed wetland, where it is purified using a soil-plant-microorganism ecosystem before being reused or discharged. Advantages: Good ecological benefits and high aesthetic appeal. Disadvantages: Large land area required.

[0129] Alternative Solution 2 (Integrated Equipment Solution): Install integrated filtration equipment (such as membrane filtration or media filtration) before the reuse pumping station to physically purify the effluent. Advantages: Small footprint, high and stable purification efficiency. Disadvantages: Requires electricity and incurs maintenance costs associated with replacing filter cartridges.

[0130] 5. Alternatives to control decision-making core Original plan: Automatic control unit 5 adopts a central controller for centralized decision-making.

[0131] Alternative Solution (Edge Computing + Blockchain): This solution employs distributed edge computing nodes, with each field or region acting as a decision-making unit. Blockchain technology is used to record regulatory decisions and water usage data, achieving distributed decision-making and trusted data storage. Advantages: Higher system reliability; single point of failure does not affect the overall system; data is tamper-proof. Disadvantages: Technically complex and costly.

[0132] Conclusion: All the above alternative solutions can achieve the core objective of this application to varying degrees—namely, adaptive drainage regulation for double-cropping rice and wheat, synergistic management of waterlogging and soil erosion, and reuse of water and fertilizer resources. The original technical solution achieves the best balance in terms of cost, reliability, and applicability, and is the preferred implementation scheme. However, the existence of the above alternative solutions precisely illustrates that the scope of protection of this application should not be limited to a specific implementation method, but should be elevated to the level of the core inventive concept of "adjusting drainage depth / capacity to adapt to the needs of crops in different seasons."

[0133] The system proposed in this application solves the problems of poor flexibility and fragmented surface and underground drainage in traditional drainage systems, and significantly improves the ability of farmland to prevent waterlogging and resist drought.

[0134] Based on the same inventive concept, this application also provides an intelligent controllable surface-to-underground coordinated drainage method for farmland underground pipes applied to the aforementioned intelligent controllable surface-to-underground coordinated drainage system. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the intelligent controllable surface-to-underground coordinated drainage method for farmland underground pipes provided below can be found in the limitations of the intelligent controllable surface-to-underground coordinated drainage system for farmland underground pipes described above, and will not be repeated here.

[0135] In one exemplary embodiment, a smart and controllable surface-subsurface coordinated drainage method for farmland underground pipes is provided, including the following steps S1 to S10.

[0136] Step S1: During the rice season, monitor the surface water depth and groundwater level of rice-wheat rotation farmland in real time; Step S2: If the real-time monitored surface water depth is greater than the rainwater storage limit, discharge the surface runoff from the surface runoff diversion module 4 to the tailwater storage and reuse channel 3; Step S3: If the real-time monitored surface water depth is less than or equal to the rainwater storage limit, compare the real-time monitored groundwater level with the target groundwater level; Step S4: When the real-time monitored groundwater level is greater than the target groundwater level, adjust the burial depth of the underground pipe drainage system to discharge groundwater to the tailwater storage and reuse channel 3; Step S5: When the real-time monitored groundwater level is equal to the target groundwater level, stop discharging the surface runoff and groundwater from the surface runoff diversion module 4 and maintain the status quo; Step S6: When the real-time monitored groundwater level is less than the target groundwater level, stop discharging the surface runoff and groundwater from the surface runoff diversion module 4 and control the tailwater storage and reuse channel 3 to irrigate farmland through the irrigation canal system. Step S7: During the wheat season, monitor the groundwater level of the rice-wheat rotation farmland in real time; Step S8: When the real-time monitored groundwater level is higher than the target groundwater level, adjust the burial depth of the underground drainage system to discharge groundwater into the tailwater storage and reuse channel 3; Step S9: When the real-time monitored groundwater level is equal to the target groundwater level, maintain the status quo; Step S10: When the real-time monitored groundwater level is lower than the target groundwater level, control the tailwater storage and reuse channel 3 to irrigate the farmland through the irrigation canal system.

[0137] The key points and areas for which this application seeks protection are as follows: 1. System Overall Architecture and Core Functions Key points: A comprehensive irrigation and drainage system integrating surface drainage, underground drainage, water level regulation, tailwater reuse, and intelligent control was constructed.

[0138] The intended protection point is an intelligent and controllable farmland underground pipe surface-underground coordinated drainage system, which consists of five core components: surface runoff guiding and drainage module 4, underground underground pipe drainage system 1, expansion joint, tailwater storage and reuse ditch 3, and automatic control unit 5, as well as the connection and cooperation between them.

[0139] 2. Adjustable groundwater level control mechanism Key point: Through the mechanical innovation of expansion joints, the effective burial depth of the underground pipe system can be dynamically changed, thereby achieving precise control of groundwater levels at different targets. This is the core of resolving the contradiction between drainage needs during the rice and wheat harvest seasons.

[0140] Points to be protected: The specific structure of the expansion joint itself, especially its combination of a retractable sleeve, a controllable drain valve, and a water level sensor.

[0141] The method and function of controlling groundwater levels at different depths by adjusting the height of the expansion joint.

[0142] 3. Intelligent control logic based on water threshold during rice and wheat growth stages Key point: The automated operation of the system is not based on a simple single water level threshold, but relies on a set of preset water regulation parameters (including upper limit of irrigation, lower limit of irrigation, and upper limit of rainwater storage) that are precisely corresponding to the growth stages of crops (rice / wheat).

[0143] Points to be protected: The automatic control unit 5 controls the specific functions of the actuator based on the preset upper limit, lower limit and upper limit of irrigation and rainwater storage thresholds for different growth stages of rice and wheat.

[0144] During the rice season, the system automatically implements a control method of "rainwater storage and irrigation control, and coordinated surface and underground drainage" based on specific parameters of different stages such as the greening stage, tillering stage, jointing and booting stage, heading and flowering stage, milk stage, and yellow ripening stage.

[0145] 4. Coordinated operation mode of surface and groundwater drainage Key point: The system does not control surface or underground drainage independently, but treats the surface runoff diversion module 4 and the underground pipe drainage system 1 as a whole, and coordinates them through the automatic control unit 5.

[0146] The system is designed to simultaneously or alternately regulate surface drainage facilities (such as ditch valves) and underground drainage facilities (such as expansion joints and concealed pipe valves) according to preset rules, so as to achieve coordinated discharge or storage of surface runoff and groundwater.

[0147] 5. Irrigation-drainage coupling and tailwater reuse mechanism Key point: By connecting the drainage system and the irrigation system through the tailwater storage and reuse channel 3, the recycling of drainage resources is realized, forming a closed loop of "irrigation-drainage-storage-return".

[0148] The specific structural relationship between the tailwater storage and reuse channel 3, the surface runoff drainage module 4, the underground pipe system, and the farmland irrigation canal system is to be protected.

[0149] The system is capable of recycling the collected wastewater for farmland irrigation, thereby reducing water consumption and nutrient loss.

[0150] 6. Dual-Season Adaptive Operation Method Key point: The same system has two completely different operating modes, which can be adaptively switched to meet the different core needs of the rice season and the wheat season.

[0151] The desired protection point: the control method under the rice season mode: with the core of achieving "rainwater storage and irrigation control" and "coordinated drainage".

[0152] The control method under the wheat harvest season is based on controlling the drainage volume and reducing the risk of waterlogging by adjusting the height of the expansion joint.

[0153] A coupled irrigation and drainage control method for rice-wheat rotation farmland based on this system includes an overall process of steps such as rice season water management, wheat season water level control, tailwater reuse, and automated control.

[0154] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0155] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An intelligent controllable farmland buried pipe surface-underground collaborative drainage system, characterized in that, The application relates to a surface runoff drainage module, an underground pipe drainage system, a groundwater level regulating device, a tail water storage and recycling ditch, a water level sensing network and an automatic control unit. The surface runoff drainage module is arranged on the surface of a rice-wheat rotation farmland, and is used for collecting the surface runoff of the rice-wheat rotation farmland. The underground pipe drainage system is buried below the ploughing layer of the rice-wheat rotation farmland, the groundwater level regulating device is installed on the underground pipe drainage system, and the groundwater level regulating device is connected with the underground pipe drainage system and the tail water storage and recycling ditch. The tail water storage and recycling ditch is connected with the surface runoff drainage module and the irrigation channel system of the rice-wheat rotation farmland respectively, and is used for collecting the tail water of the surface runoff and the underground pipe drainage system and irrigating the farmland through the irrigation channel system. The water level sensing network is used for monitoring the surface water depth and the groundwater level of the rice-wheat rotation farmland in real time. The automatic control unit is internally provided with water demand parameters of the rice and the wheat in different growth periods. The water demand parameters include a rain storage upper limit and a target groundwater level. In the rice season, the automatic control unit is used for monitoring the surface water depth and the groundwater level of the rice-wheat rotation farmland in real time. If the real-time monitored surface water depth is greater than the rain storage upper limit, the surface runoff of the surface runoff drainage module is drained to the tail water storage and recycling ditch. If the real-time monitored surface water depth is less than or equal to the rain storage upper limit, the real-time monitored groundwater level is compared with the target groundwater level.

2. The intelligent controllable farmland buried pipe surface-underground collaborative drainage system according to claim 1, characterized in that, When the real-time monitored groundwater level is greater than the target groundwater level, the opening degree of the underground drainage valve in the underground pipe drainage system and the height of the groundwater level regulating device are adjusted, so that the underground water is drained to the tail water storage and recycling ditch. When the real-time monitored groundwater level is equal to the target groundwater level, the surface runoff of the surface runoff drainage module and the underground water are stopped from being drained, and the present situation is maintained. When the real-time monitored groundwater level is less than the target groundwater level, the tail water storage and recycling ditch is controlled to irrigate the farmland through the irrigation channel system. In the wheat season, the automatic control unit is used for monitoring the groundwater level of the rice-wheat rotation farmland in real time.

3. The intelligent controllable farmland buried pipe surface-underground collaborative drainage system according to claim 1, characterized in that, When the real-time monitored groundwater level is greater than the target groundwater level, the opening degree of the underground drainage valve in the underground pipe drainage system and the height of the groundwater level regulating device are adjusted, so that the underground water is drained to the tail water storage and recycling ditch. When the real-time monitored groundwater level is equal to the target groundwater level, the present situation is maintained. When the real-time monitored groundwater level is less than the target groundwater level, the tail water storage and recycling ditch is controlled to irrigate the farmland through the irrigation channel system. The underground pipe drainage system comprises a pipe network, a control gate valve, a gradual change section and a water collecting well cover. The control gate valve is arranged on the pipe network. The narrow end of the gradual change section is connected with the outlet end of the pipe network, and the wide end of the gradual change section is connected with the groundwater level regulating device. The groundwater level regulating device is arranged in the water collecting well cover. The groundwater level regulating device comprises an adjusting elbow, a drainage vertical pipe, a plurality of first drainage pipes and a plurality of first drainage gate valves. One end of the adjusting elbow is connected with the outlet end in the underground pipe drainage system, and the other end of the adjusting elbow is connected with one end of the drainage vertical pipe. The drainage vertical pipe is arranged along the underground vertical depth direction and has an adjustable height. A plurality of first drainage pipes are arranged at different heights of the vertical drainage pipe, and the plurality of first drainage pipes are connected to the tail water storage and reuse channel; a first drainage gate valve is installed on each of the first drainage pipes; Based on the principle of the communicating vessel, the underground water level at different depths is controlled by adjusting the height of the vertical drainage pipe.

4. The intelligent controllable farmland buried pipe surface-underground collaborative drainage system according to claim 1, characterized in that, The underground water level control device comprises a telescopic sleeve, a controllable drainage valve, a plurality of second drainage pipes, and a plurality of second drainage gate valves; The plurality of second drainage pipes are arranged at different depths underground, and the plurality of second drainage pipes are connected to the tail water storage and reuse channel; a second drainage gate valve is installed on each of the second drainage pipes; One end of the telescopic sleeve is connected to the outlet end of the underground sewerage system; By adjusting the height of the telescopic sleeve along the vertical depth direction, the other end of the telescopic sleeve is connected to the second drainage pipe at different depths, so that the underground sewerage system is connected to the tail water storage and reuse channel.

5. The intelligent controllable farmland buried pipe surface-underground collaborative drainage system according to claim 1, characterized in that, The tail water storage and reuse channel comprises a drainage channel, a water pump, plant filter material, and a reuse water pump; The drainage channel is connected to the surface runoff diversion module and the underground water level control device, and the water pump is arranged on the connecting pipeline between the drainage channel and the underground water level control device; the water pump is used to pump the underground water to the drainage channel through the underground sewerage system and the underground water level control device when needed; Plant filter material is laid inside the drainage channel, and the plant filter material is used to purify the water inside the drainage channel; The drainage channel is connected to the irrigation channel system of the rice-wheat rotation farmland, and the reuse water pump is arranged on the connecting pipeline between the drainage channel and the irrigation channel system of the rice-wheat rotation farmland; the reuse water pump is used to pump the purified water in the drainage channel back to the irrigation channel system to irrigate the rice-wheat rotation farmland.

6. The intelligent controllable farmland buried pipe surface-underground collaborative drainage system according to claim 1, characterized in that, The water level sensing network comprises underground water level sensors and surface water level sensors; The underground water level sensors are arranged in the underground water level control device, and the underground water level sensors are used to monitor the underground water level of the rice-wheat rotation farmland in real time; The surface water level sensors are used to monitor the surface water depth of the rice-wheat rotation farmland in real time.

7. The intelligent controllable farmland buried pipe surface-underground collaborative drainage system according to claim 1, characterized in that, In terms of stopping the discharge of surface runoff and underground water from the surface runoff diversion module, the automatic control unit comprises: By closing the surface drainage gate of the surface runoff diversion module and the underground drainage valve in the underground sewerage system, the discharge of surface runoff and underground water from the surface runoff diversion module is stopped. 8.The intelligent controllable farmland buried pipe surface-underground collaborative drainage system according to claim 1, characterized in that, The automatic control unit is used to collect historical rainfall data under different weather conditions and corresponding water levels; the water levels are field water depths or underground water levels; According to the historical rainfall data under different weather conditions and the corresponding water levels, a machine learning model is trained to obtain a water level prediction model; Rainfall data in a weather forecast is obtained and input into the water level prediction model to predict future water levels; When in the rice season, the future water level is compared with the allowable flooding depth of each growth period of rice; if the future water level is greater than the allowable flooding depth of each growth period of rice, an early warning is issued; When in the wheat season, the future water level is compared with the maximum allowable underground water level in the wheat season; if the future water level is greater than the maximum allowable underground water level in the wheat season, an early warning is issued. 9.The intelligent controllable farmland buried pipe surface-underground collaborative drainage system according to claim 1, characterized in that, The automatic control unit is used for accessing the weather forecast data, and when the weather forecast data contains heavy rain, the depth of the underground pipe drainage system is adjusted before the heavy rain comes, so that the underground water is drained to the tail water storage and reuse channel, and the underground water level is lowered.

10. An intelligent controllable farmland buried pipe surface-underground collaborative drainage method, characterized in that, The intelligent controllable farmland buried pipe surface-underground collaborative drainage method is applied to the intelligent controllable farmland buried pipe surface-underground collaborative drainage system of any one of claims 1-9, and the intelligent controllable farmland buried pipe surface-underground collaborative drainage method comprises: In the rice season, the surface water depth and the underground water level of the rice-wheat rotation farmland are monitored in real time; If the real-time monitored surface water depth is greater than the upper limit of rain storage, the surface runoff of the surface runoff guide module is drained to the tail water storage and reuse channel; If the real-time monitored surface water depth is less than or equal to the upper limit of rain storage, the real-time monitored underground water level is compared with the target underground water level; When the real-time monitored underground water level is greater than the target underground water level, the depth of the underground pipe drainage system is adjusted, so that the underground water is drained to the tail water storage and reuse channel; When the real-time monitored underground water level is equal to the target underground water level, the surface runoff of the surface runoff guide module and the underground water are stopped, and the present situation is maintained; When the real-time monitored underground water level is less than the target underground water level, the surface runoff of the surface runoff guide module and the underground water are stopped, and the tail water storage and reuse channel irrigates the farmland through the irrigation canal system; In the wheat season, the underground water level of the rice-wheat rotation farmland is monitored in real time; When the real-time monitored underground water level is greater than the target underground water level, the depth of the underground pipe drainage system is adjusted, so that the underground water is drained to the tail water storage and reuse channel; When the real-time monitored underground water level is equal to the target underground water level, the present situation is maintained; When the real-time monitored underground water level is less than the target underground water level, the tail water storage and reuse channel irrigates the farmland through the irrigation canal system.

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