An irrigation and drainage integrated field test device and an application method thereof

Abstract

This invention provides an integrated irrigation and drainage field experimental device and its application method, relating to the field of farmland irrigation technology. The integrated irrigation and drainage field experimental device includes: a storage pipeline mechanism, an irrigation control mechanism, a drainage metering mechanism, and a soil testing mechanism; the storage pipeline mechanism includes a water tank, a valve connected to the water tank, and a submerged pipe connected to the water tank via the valve and a tee pipe. This invention uses a dedicated submerged pipe buried underground as a shared irrigation and drainage channel. Soil sensors collect real-time data on soil moisture, temperature, and conductivity at different depths, which is transmitted to a control terminal via a host computer. The data, combined with the field water holding capacity threshold during the crop's growth period, determines whether irrigation or drainage is necessary. An intelligent water level controller enables automatic control of the water tank level, ultimately automating the irrigation process.

Description

Technical Field

[0001] This invention relates to the field of farmland irrigation technology, specifically to an integrated irrigation and drainage field experimental device and its application method. Background Technology

[0002] Black soil regions are important maize production bases. Black soil is characterized by high fertility and strong water retention. However, the region's climate suffers from uneven seasonal rainfall, making it prone to extreme droughts and floods, which severely impact maize growth and development. Irrigation and drainage are key agricultural technologies for regulating soil moisture and ensuring high and stable crop yields. Rational irrigation can replenish water for crops during droughts, meeting their water needs throughout their growth cycle; effective drainage can promptly remove excess water during floods, preventing waterlogging that can lead to root hypoxia and root rot, while also reducing soil nutrient loss and black soil degradation. With the development of modern agriculture towards precision and intelligence, field water management technologies are receiving increasing attention.

[0003] Currently, irrigation and drainage systems for maize and similar field environments in the black soil region are mainly divided into two categories: separate irrigation and separate drainage. Separate irrigation systems include surface flood irrigation, drip irrigation, and sprinkler irrigation. While flood irrigation has a simple structure, it suffers from low water resource utilization, poor uniformity, and a tendency to cause soil compaction. Drip irrigation and sprinkler irrigation, although improving water use efficiency, are only suitable for water-saving irrigation and lack drainage capabilities. Furthermore, their complex pipeline layout can easily interfere with field management operations. Separate drainage systems primarily use underground pipes, achieving gravity drainage through perforated pipes buried at a certain slope. However, their function is limited and cannot be used for irrigation. If irrigation is required, additional equipment is needed, increasing costs and operational complexity. In addition, existing attempts to combine irrigation and drainage functions generally suffer from design flaws. For example, shared pipelines lack precise flow and water level control, leading to uneven irrigation and incomplete drainage. They also lack real-time soil moisture monitoring and automatic control systems, relying on manual operation, making it difficult to achieve precise control of irrigation and drainage according to crop needs, resulting in insufficient overall efficiency and adaptability. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an integrated irrigation and drainage field experimental device and its application method. This solves the problems of the irrigation and drainage equipment currently used in maize field production and experiments in black soil areas, which generally suffer from single functions and insufficient control precision, making it difficult to adapt to the soil characteristics of black soil areas and the dynamic water requirements of maize during its growth period.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: an integrated irrigation and drainage field test device, comprising: a storage pipeline mechanism, an irrigation control mechanism, a drainage metering mechanism, and a soil testing mechanism;

[0006] The storage pipeline structure includes a water tank, a valve connected to the water tank, and a concealed pipe connected to the water tank through the valve and a tee pipe;

[0007] The irrigation control mechanism includes a water level controller, a water level detection head connected to the water level controller and extending into the water tank, an irrigation pump controlled by the water level controller, a first flow meter installed on the irrigation pump pipeline, and a control box power supply that supplies power to the water level controller.

[0008] The drainage metering mechanism includes a drainage pump installed in the water tank, a second flow meter installed on the drainage pump pipeline, and a power plug connected to the drainage pump.

[0009] The soil testing device includes a main unit, multiple soil sensors connected to the main unit, an antenna connected to the main unit for wireless communication, and a power supply for powering the main unit.

[0010] Preferably, the concealed pipe comprises two parallel solid-walled PE pipes, each with a length of 11m and a diameter of 125mm. The upper half of the pipe body is uniformly perforated with a perforation rate of 4.3% and a single hole diameter of 6mm. The pipe is wrapped with geotextile.

[0011] The two underground pipes are connected at right angles by a connecting pipe and buried 60cm underground. The slope ratio is 5 / 1000 and the distance between the two underground pipes is 6m.

[0012] Preferably, the water tank is buried 120cm underground and connected to the concealed pipe via a T-junction, with the connection point located 40cm above the bottom of the water tank.

[0013] Preferably, the number of soil sensors is 5, which are buried at soil depths of 10cm, 30cm, 50cm, 70cm and 90cm respectively, and the material of the underground pipe is PE solid wall pipe.

[0014] Preferably, the water level detection head includes three detection heads: high, medium, and low, which are respectively suspended at different heights inside the water tank.

[0015] Preferably, the backfill structure after the buried pipe is as follows: first, 8cm of fine sand is laid on the upper part of the buried pipe, then a 12cm thick layer of coarse sand is covered to form a filter layer, and finally the original soil is used to backfill to the ground surface.

[0016] A field test method for integrated irrigation and drainage, applied to an integrated irrigation and drainage field test device, includes the following steps:

[0017] S1: Preset control parameters, including field water holding capacity threshold, irrigation trigger lower limit threshold, and high and medium water level settings for the water tank;

[0018] S2: Real-time data on soil volumetric water content is collected using the soil sensor;

[0019] S3: Drainage decision and execution: If the soil volumetric moisture content is greater than or equal to the field capacity threshold, the valve is opened and the metering pump is started to drain the water until the soil volumetric moisture content drops to the level of the field capacity threshold.

[0020] S4: Irrigation decision and execution: If the soil volumetric moisture content is less than or equal to the irrigation trigger lower threshold, the valve is opened, the water level controller and the irrigation pump are started to irrigate until the soil volumetric moisture content rises to equal the field capacity threshold.

[0021] S5: Return to step S2 to form a closed-loop automatic control.

[0022] Preferably, the irrigation trigger lower limit threshold is set according to the water requirement characteristics of crops at different growth stages. During the drainage process in step S3, the drainage flow rate and drainage time are recorded by the second flow meter.

[0023] This invention provides an integrated irrigation and drainage field experimental device and its application method. It has the following beneficial effects:

[0024] This invention provides an integrated irrigation and drainage field experimental device and its application method. Compared to the traditional method that requires two separate sets of pipelines for irrigation and drainage, this invention uses underground pipes with specific parameters, integrated with water tanks and valves, allowing the same underground pipe channel to perform both water supply and drainage functions. This not only reduces the purchase and construction costs of a single pipeline but also avoids interference with the integrity of the field plot caused by the cross-layout of two sets of pipelines. Furthermore, the underground pipes use right-angle heat fusion connections and standardized three-way valves, making installation convenient and further reducing labor input. Regarding improved field applicability, this technology features a double anti-clogging structure with geotextile wrapping the underground pipes and a sand and gravel filter layer, effectively preventing black soil particles from clogging the pipes and ensuring uniform irrigation and drainage and long-term stable operation. Combined with the arrangement of two underground pipes with a 6-meter spacing, a 60-centimeter burial depth, and a 5 / 1000 slope ratio, efficient gravity-driven drainage is achieved, making the overall structure more reliable and adaptable to the characteristics of black soil regions.

[0025] This invention provides an integrated irrigation and drainage field experimental device and its application method. This technology constructs a 0-100 cm layered monitoring network to collect real-time data on soil moisture content, temperature, and conductivity at each layer, transmitting this data wirelessly to a control terminal. This allows irrigation and drainage decisions to be based on precise soil data rather than human experience, enabling precise management based on the field water holding capacity threshold during the crop's growth stage, effectively avoiding over- or under-irrigation. Simultaneously, an intelligent water level controller enables automated operation at a constant head, automatically starting and stopping irrigation pumps, reducing manual intervention and improving responsiveness. Regarding data support, by connecting flow meters in series with the drainage pipes, this technology allows for the synchronous recording and uploading of drainage flow, time, and soil data, ensuring traceability and analyzability throughout the entire process, greatly enhancing the scientific rigor and data value of the field experiment. Furthermore, the modular design allows this technology to be flexibly adapted to different crops and soil types by adjusting parameters such as the spacing between underground pipes and the burial depth of sensors, broadening its application scope and reducing promotion costs. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the storage pipeline mechanism of the present invention;

[0027] Figure 2 This is a schematic diagram of the irrigation control mechanism of the present invention;

[0028] Figure 3 This is a schematic diagram of the drainage metering mechanism of the present invention;

[0029] Figure 4 This is a schematic diagram of the soil testing mechanism of the present invention.

[0030] The components include: 1. Storage pipeline mechanism; 101. Water tank; 102. Valve; 103. Concealed pipe; 2. Irrigation control mechanism; 201. Water level controller; 202. Water level detection terminal; 203. Irrigation pump; 204. First flow meter; 205. Control box power supply; 3. Drainage metering mechanism; 301. Drainage pump; 302. Second flow meter; 303. Power plug; 4. Soil testing mechanism; 401. Main unit; 402. Sensor; 403. Antenna; 404. Power supply. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1-4As shown, this embodiment of the invention provides an integrated irrigation and drainage field test device, including: a storage pipeline mechanism 1, an irrigation control mechanism 2, a drainage metering mechanism 3, and a soil testing mechanism 4;

[0033] The storage pipeline mechanism 1 includes a water tank 101, a valve 102 connected to the water tank 101, and a concealed pipe 103 connected to the water tank 101 through the valve 102 and a tee pipe.

[0034] The irrigation control mechanism 2 includes a water level controller 201, a water level detection end 202 connected to the water level controller 201 and extending into the water tank 101, an irrigation pump 203 controlled by the water level controller 201, a first flow meter 204 installed on the pipeline of the irrigation pump 203, and a control box power supply 205 that supplies power to the water level controller 201.

[0035] The drainage metering mechanism 3 includes a drainage pump 301 installed in the water tank 101, a second flow meter 302 installed on the pipeline of the drainage pump 301, and a power plug 303 connected to the drainage pump 301.

[0036] The soil testing unit 4 includes a host 401, multiple soil sensors 402 connected to the host 401, an antenna 403 connected to the host 401 for wireless communication, and a power supply 404 that powers the host 401.

[0037] The concealed pipe 103 consists of two parallel solid-walled PE pipes, each 11m long and 125mm in diameter. The upper half of the pipe body is evenly perforated with a perforation rate of 4.3% and a single hole diameter of 6mm. The pipe is wrapped with geotextile.

[0038] The two underground pipes 103 are connected at right angles by a connecting pipe and buried 60cm underground. The slope ratio is 5‰ and the distance between the two underground pipes 103 is 6m.

[0039] Water tank 101 is buried 120cm underground and connected to concealed pipe 103 via a T-junction. The connection point is located 40cm above the bottom of water tank 101. Five soil sensors 402 are installed at soil depths of 10cm, 30cm, 50cm, 70cm, and 90cm respectively. Concealed pipe 103 is made of solid PE pipe. Water level detection terminals 202 include high, medium, and low detection terminals, suspended at different heights inside water tank 101. The backfill structure after the concealed pipe 103 is as follows: an 8cm layer of fine sand is laid on the upper part of the concealed pipe 103, followed by a 12cm layer of coarse sand to form a filter layer, and finally, the original soil is used to backfill to the surface.

[0040] A field test method for integrated irrigation and drainage, applied to an integrated irrigation and drainage field test device, includes the following steps:

[0041] S1: Preset control parameters, including field water holding capacity threshold, irrigation trigger lower limit threshold, and high and medium water level settings for water tank 101;

[0042] S2: Real-time data collection of soil volumetric moisture content using soil sensor 402;

[0043] S3: Drainage decision and execution: If the soil volumetric moisture content is greater than or equal to the field capacity threshold, then open valve 102 and start drainage pump 301 to drain water until the soil volumetric moisture content drops to equal the field capacity threshold.

[0044] S4: Irrigation decision and execution: If the soil volumetric moisture content is less than or equal to the lower threshold of irrigation trigger, valve 102 is opened, water level controller 201 and irrigation pump 203 are started to irrigate until the soil volumetric moisture content rises to equal the field capacity threshold.

[0045] S5: Return to step S2 to form a closed-loop automatic control.

[0046] The lower threshold for irrigation triggering is set according to the water requirement characteristics of crops at different growth stages. During the drainage process in step S3, the drainage flow rate and drainage time are recorded by the second flow meter 302.

[0047] The invention begins with installation and parameter presets. In a selected 12m x 12m standard test plot, a trench with a starting depth of 60cm and a slope of 5‰ is excavated. Two PE solid-wall main underground pipes 103, each 11m long and 125mm in diameter, are laid parallel at 6-meter intervals. The upper half of each pipe has evenly spaced 6mm diameter seepage holes and is completely wrapped with geotextile to prevent clogging. During installation, a 5‰ slope is strictly maintained, sloping towards the water tank 101. The underground pipes 103 are connected via a three-way valve to a 1m long, 0.5m wide, and 1.8m high polypropylene (PP) water tank 101, buried 120cm underground. The connection point is located 40cm above the bottom of the water tank 101. During backfilling, a 80-cm thick layer of fine sand is first placed on the upper half of the underground pipe 103, followed by a 12-cm thick layer of coarse sand to form a filter layer. Finally, the original soil is used to backfill to the surface. This structural design significantly improves the lateral uniformity of irrigation water penetration and drainage efficiency. Simultaneously, at representative locations between the two underground pipes 103, five integrated soil sensors 402 are vertically buried in soil layers at depths of 10, 30, 50, 70, and 90 cm, respectively, to simultaneously monitor volumetric moisture content, temperature, and electrical conductivity. After installation, based on the specific growth stage of the corn crop, the corresponding field water holding capacity threshold, irrigation trigger lower limit, and medium and high water level settings required for stable irrigation in water tank 101 are manually set at the control terminal or automatically retrieved from the cloud database. This standardized and modular installation process ensures precise adaptation of the core components of the device to the field environment of the black soil region, laying a solid physical foundation for subsequent automated operation and fundamentally avoiding interference with the integrity of the experimental plot and the accuracy of data caused by laying two separate pipe networks.

[0048] After system startup, it enters a fully automated monitoring and intelligent decision-making cycle. The soil sensor network 402 continuously collects profile moisture data of the entire soil layer (0-100 cm) every 30 minutes, and transmits it in real-time to a remote computer network platform via the host 401 and wireless communication module, enabling visualization of soil moisture data. The control terminal automatically compares the real-time soil volumetric moisture content with the preset field capacity threshold, forming a closed-loop decision-making logic. If the monitored data is higher than or equal to the field capacity threshold, the system immediately determines a "drainage required" state; if the data is lower than or equal to the irrigation trigger limit, it determines a "irrigation required" state; if the data is between the two, the system maintains monitoring. This process requires no manual intervention. Its core advantage lies in constructing a three-dimensional, real-time soil moisture monitoring network, transforming irrigation and drainage decisions from relying on fuzzy experience to scientific judgment based on precise data. This allows for precise matching of the dynamic water requirements of maize at each growth stage, effectively avoiding the stress on crop roots caused by insufficient irrigation, over-irrigation, or untimely drainage under traditional methods, significantly improving the scientific nature of field water management.

[0049] When the system determines that irrigation is needed, the intelligent irrigation process is automatically triggered. The control terminal first issues a command to open the valve 102 connecting the water tank 101 and the underground pipe 103 system, and simultaneously starts the irrigation control mechanism 2. The irrigation pump 203, installed between the external water source and the water tank 101, begins to inject water into the water tank 101, and the first flow meter 204 connected in series on its pipeline records the water replenishment flow rate simultaneously. The three water level detection terminals 202 suspended in the water tank 101 (high, medium, and low) are linked in real time with the intelligent water level controller 201 to form a precise water level control mechanism: when the water level is lower than the medium terminal, the controller commands the pump to continue running; once the water level rises to the high terminal, the pump automatically stops. As water continuously seeps into the field through the underground pipe 103 during irrigation, the water level in the water tank 101 will slowly drop, and when it falls below the medium terminal again, the pump will restart. This cycle ensures that the water level in tank 101 remains stable between the medium and high levels throughout the irrigation operation, providing a continuous and constant water supply pressure for the underground pipe network 103. Driven by this pressure, irrigation water first enters the surrounding sand and gravel filter layer through the uniform openings in the upper part of the pipe 103, and then slowly and evenly seeps laterally into the surrounding black soil tillage layer. During irrigation, the soil sensor network 402 continuously monitors changes in moisture content until the data rises back to the field water holding capacity threshold, at which point the system automatically closes valve 102 and stops the water pump, completing the irrigation. The outstanding advantage of this process is that it achieves full automation from decision-making to execution and a stable "constant head" water supply, eliminating the need for manual operation and greatly reducing labor costs. At the same time, constant pressure infiltration ensures uniform water distribution in the field, overcoming the inherent defects of uneven distribution in traditional flood irrigation and the inability to drain water in drip irrigation.

[0050] When the system determines that drainage is needed, the efficient drainage process is immediately initiated. The control terminal opens valve 102 of the same underground pipe system 103. At this time, excess gravity water in the field soil, under the combined effect of soil water potential difference and the slope of the underground pipe 103, naturally flows into the pipe through the holes in the wall of the underground pipe 103 and flows rapidly towards the water tank 101 along a 5‰ slope. The field water collected in the water tank 101 is promptly discharged to the external ditch by an independent drainage pump 301 pre-placed in the water tank 101. A second flow meter 302 is connected in series on the outlet pipe of this pump to accurately record the drainage flow rate and time. During the drainage process, the soil moisture monitoring system works continuously, providing real-time feedback on the decrease in soil moisture content. Once the monitoring shows that the moisture content of each soil layer has dropped to the field water holding capacity threshold, indicating that the excess water in the field has been drained and the soil moisture has returned to a suitable state, the system automatically closes the drainage valve 102 and stops the drainage pump 301, ending the drainage operation. After either irrigation or drainage operations are completed, the system immediately returns to continuous monitoring mode, ready to respond to the next change in water availability, forming a complete closed-loop intelligent control system encompassing monitoring, decision-making, execution, and feedback. The significant advantage of this drainage mode lies in its ability to achieve rapid water collection and discharge using the same underground pipe network in reverse, resulting in a swift response and effectively preventing soil flooding and root hypoxia caused by summer waterlogging. Simultaneously, the synchronous recording and uploading of drainage flow data makes each irrigation and drainage event traceable and analyzable, providing valuable data support for optimizing water management strategies and conducting agricultural scientific research, greatly enhancing the value of field trials.

[0051] Disadvantages of existing technology

[0052] Single function, unable to achieve integrated irrigation and drainage: Existing devices are mostly designed for separate irrigation or separate drainage. If the needs of irrigation and drainage need to be met simultaneously, two separate sets of irrigation and drainage equipment need to be laid in the field. This not only increases the cost of equipment purchase and installation, but also leads to messy pipeline layout in the field, which interferes with the integrity of the field test plots and affects the accuracy of the test data.

[0053] Low control precision and inability to adapt to crop growth stage water requirements: Existing devices lack a supporting real-time soil moisture monitoring system, making it impossible to accurately obtain key parameters such as temperature, humidity, and electrical conductivity of different soil layers. The timing and volume of irrigation and drainage are all judged by human experience, which can easily lead to problems such as insufficient irrigation, over-irrigation, or untimely drainage. In particular, it cannot meet the specific requirements of different growth stages of crops such as corn for the proportion of field water holding capacity.

[0054] Low level of automation and high labor costs: The start-up, shutdown and mode switching of existing irrigation and drainage devices mostly rely on manual operation. For example, water pumps need to be turned on manually during irrigation, and water accumulation needs to be monitored and drainage pipes opened manually during drainage. The operation is cumbersome and the response is slow. Although some simple integrated devices attempt to share pipelines, they do not have intelligent water level control mechanisms and cannot realize automatic adjustment of the water level in water tank 101 and cyclic control of the irrigation and drainage process. They require continuous manual monitoring, which greatly increases labor costs.

[0055] The structural design is unreasonable and the adaptability is poor: the existing underground pipe 103 drainage device is mostly a single set of pipes, with a limited drainage range, which is difficult to adapt to the specifications of conventional field test plots; at the same time, the pipe connection method is simple, which is prone to problems such as leakage and blockage, affecting irrigation and drainage efficiency; the existing device for irrigation and drainage shared pipelines has not reasonably designed the pipe slope ratio and opening parameters, resulting in uneven water penetration during irrigation and incomplete drainage of accumulated water during drainage.

[0056] To address the shortcomings of the existing technology, the purpose of this invention is to provide an integrated irrigation and drainage field experimental device suitable for maize in black soil regions. The specific objectives are as follows:

[0057] To achieve integrated irrigation and drainage functions and reduce equipment and construction costs: By optimizing the design of the underground pipe 103 and adopting the linkage structure of the three-way valve 102 and the water tank 101, the same set of equipment can complete both irrigation operations during drought and drainage operations during floods. There is no need to lay two separate sets of irrigation and drainage equipment, which simplifies the layout of field pipelines, reduces equipment purchase and construction costs, and ensures the integrity of the experimental plot.

[0058] To improve the precision of soil moisture regulation and adapt to the needs of crop growth stages: By deploying multiple layers of soil sensors 402, parameters such as temperature, humidity (volume water content), and electrical conductivity of the 0-100cm soil layer are monitored in real time. Combined with a network platform, the data is visualized in real time. Based on the field water holding capacity threshold corresponding to the crop growth stage, irrigation and drainage actions are automatically triggered to ensure that the soil moisture is always within the range suitable for crop growth.

[0059] To automate the irrigation and drainage process and reduce labor costs: By setting up a linkage mechanism between the intelligent water level controller 201 and the water pump and valve 102, the system can automatically monitor the high and low water levels of the water tank 101 and control water replenishment and shutdown, thereby realizing the automated operation of the irrigation-water level maintenance-drainage cycle without the need for continuous manual supervision, thus improving the response speed and ease of operation of irrigation and drainage operations.

[0060] Optimize structural design to improve adaptability and stability: Adopt a symmetrical arrangement of double underground pipes 103, match the specifications of a 12m×12m field test plot, and reasonably set the burial depth, slope ratio, opening parameters, and anti-clogging design of the underground pipes 103, to ensure uniform water infiltration during irrigation and rapid drainage of accumulated water during drainage. At the same time, it improves the device's anti-clogging ability and long-term operational stability, and can be extended to other field environments that require irrigation and drainage.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A field experimental device integrating irrigation and drainage, characterized in that, include: Storage pipeline mechanism (1), irrigation control mechanism (2), drainage metering mechanism (3) and soil testing mechanism (4); The storage pipeline mechanism (1) includes a water tank (101), a valve (102) connected to the water tank (101), and a concealed pipe (103) connected to the water tank (101) through the valve (102) and a tee pipe. The irrigation control mechanism (2) includes a water level controller (201), a water level detection end (202) connected to the water level controller (201) and extending into the water tank (101), an irrigation pump (203) controlled by the water level controller (201), a first flow meter (204) installed on the pipeline of the irrigation pump (203), and a control box power supply (205) that supplies power to the water level controller (201). The drainage metering mechanism (3) includes a drainage pump (301) installed in the water tank (101), a second flow meter (302) installed on the pipeline of the drainage pump (301), and a power plug (303) connected to the drainage pump (301). The soil testing device (4) includes a host (401), a plurality of soil sensors (402) connected to the host (401), an antenna (403) connected to the host (401) for wireless communication, and a power supply (404) for powering the host (401).

2. The integrated irrigation and drainage field test device according to claim 1, characterized in that: The concealed pipe (103) includes two parallel solid PE pipes, each with a length of 11m and a diameter of 125mm. The upper half of the pipe body is evenly perforated with a perforation rate of 4.3% and a single hole diameter of 6mm. The pipe is wrapped with geotextile. The two underground pipes (103) are connected at right angles by a connecting pipe and buried 60cm deep underground. The slope ratio is 5 / 1000 and the distance between the two underground pipes (103) is 6m.

3. The integrated irrigation and drainage field test device according to claim 1, characterized in that: The water tank (101) is buried 120cm underground and is connected to the underground pipe (103) through a T-junction. The connection point is located 40cm above the bottom of the water tank (101).

4. The integrated irrigation and drainage field test device according to claim 1, characterized in that: The number of soil sensors (402) is 5, which are buried at soil depths of 10cm, 30cm, 50cm, 70cm and 90cm respectively. The material of the underground pipe (103) is PE solid wall pipe.

5. The integrated irrigation and drainage field test device according to claim 1, characterized in that: The water level detection head (202) includes three detection heads: high, medium and low, which are suspended at different heights inside the water tank (101).

6. The integrated irrigation and drainage field test device according to claim 1, characterized in that: The backfill structure after the buried pipe (103) is as follows: first, 8cm of fine sand is laid on the upper part of the buried pipe (103), then a 12cm thick layer of coarse sand is covered to form a filter layer, and finally the original soil is used to backfill to the ground surface.

7. A field test method for integrated irrigation and drainage, applied to the integrated irrigation and drainage field test apparatus as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Preset control parameters, including field water holding capacity threshold, irrigation trigger lower limit threshold, and high and medium water level settings for water tank (101); S2: Real-time data on soil volumetric water content is collected using the soil sensor (402); S3: Drainage decision and execution: If the soil volumetric moisture content is greater than or equal to the field capacity threshold, the valve (102) is opened and the drainage pump (301) is started to drain water until the soil volumetric moisture content drops to equal to the field capacity threshold. S4: Irrigation decision and execution: If the soil volumetric moisture content is less than or equal to the irrigation trigger lower threshold, the valve (102) is opened, and the water level controller (201) and the irrigation pump (203) are started to irrigate until the soil volumetric moisture content rises to equal the field capacity threshold. S5: Return to step S2 to form a closed-loop automatic control.

8. The field test method for integrated irrigation and drainage according to claim 7, characterized in that: The lower threshold for triggering irrigation is set according to the water requirements of crops at different growth stages. During the drainage process in step S3, the drainage flow rate and drainage time are recorded by the second flow meter (302).

Images