A controllable temperature drip irrigation system for root zone water, heat and salt transport simulation

Abstract

The utility model discloses a kind of temperature-controllable drip irrigation systems for root zone hydrothermal salt transport simulation, belong to agricultural water and soil engineering experimental device technical field. Including experimental box module, temperature-controllable drip irrigation module, integrated monitoring module;Experimental box module includes main box, drainage layer being arranged at the bottom of the main box and the drainage port being communicated with the drainage layer, main box is filled with cultivation matrix, outer surface is wrapped with heat preservation layer;Temperature-controllable drip irrigation module includes water storage unit, water pump, temperature control unit, water supply pipeline and multiple drippers, dripper is arranged in the upper surface of the main box with two-dimensional grid, and the temperature of irrigation water is adjustable;Integrated monitoring module includes multiple soil sensors for measuring cultivation matrix parameters and data collector. The system can in situ, synchronously capture the dynamic change of the multi-dimensional parameters such as moisture, temperature, salinity of cultivation matrix in different positions, and provide high-quality data support for revealing the hydrothermal salt transport law.

Description

Technical Field

[0001] This utility model relates to the technical field of experimental devices for agricultural water and soil engineering, and in particular to a temperature-controlled drip irrigation system for simulating root zone water, heat and salt transport. Background Technology

[0002] Drip irrigation is a highly efficient water-saving irrigation method in modern agriculture. Its core technology lies in delivering water and nutrients directly to the root zone of crops through precise irrigation regimes. In the optimization research of drip irrigation regimes, irrigation water temperature is a crucial environmental parameter, directly affecting water infiltration, heat conduction, and salt transport in the soil or cultivation substrate, thereby influencing crop growth and development. Therefore, quantitatively studying the independent effects of irrigation water temperature on water, heat, and salt transport in the root zone under controlled experimental conditions is of great significance for deepening the understanding of agricultural soil and water processes and optimizing irrigation strategies.

[0003] To conduct relevant research, laboratory-scale soil columns or planting boxes are commonly used as simulation devices in this field. Existing such devices generally include a container for filling with soil or substrate, a simple drip irrigation system, and sensors for monitoring certain parameters. The drip irrigation system typically consists of a water tank, pump, piping, and drippers, providing basic irrigation functionality. For monitoring, methods such as scattering a small number of sensors within the container or destructive sampling after the experiment are often employed to obtain data on soil moisture content, temperature, etc. These approaches provide fundamental tools for studying water and salt transport; their technical essence lies in simulating the field environment through physical models.

[0004] However, the aforementioned existing technical solutions have significant drawbacks. First, their water supply systems lack active and precise temperature control, making it difficult to stabilize the irrigation water temperature at a constant target value. This hinders the effective isolation of water temperature variables for independent research, resulting in severe environmental thermal interference. Second, the monitoring methods are relatively outdated. Destructive sampling cannot obtain continuous dynamic data, and sparse sensor deployment makes it difficult to capture the high-resolution distribution details of water, heat, and salt parameters in three-dimensional space, leading to low spatiotemporal resolution of the data. Finally, the device itself has poor insulation performance, ambiguous boundary conditions, and uncontrollable heat loss, resulting in low reliability and repeatability of experimental results, making it difficult to meet the high-quality experimental data requirements for high-precision CFD (Computational Fluid Dynamics) numerical model verification. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a temperature-controlled drip irrigation system for simulating root zone hydrothermal and salt transport, aiming to solve the problem of how to provide an integrated experimental system with clearly defined boundary conditions, controllable irrigation water temperature, and the ability to achieve three-dimensional high-density in-situ monitoring.

[0006] The technical solution adopted in this utility model is as follows: A temperature-controlled drip irrigation system for simulating root zone hydrothermal-salt transport includes: The experimental chamber module includes a main chamber, a drainage layer located at the bottom of the main chamber, and a drainage outlet communicating with the drainage layer. The main chamber is used to fill the cultivation substrate, and its outer surface is covered with an insulation layer. A temperature-controlled drip irrigation module includes a water storage unit, a water pump, a temperature control unit, a water supply pipeline, and multiple drippers. The inlet of the water pump is connected to the water storage unit, and the outlet is connected in parallel to the multiple drippers through the water supply pipeline. The multiple drippers are arranged in a two-dimensional grid on the upper surface of the main housing. The temperature control unit is located on the pipeline at the outlet of the water pump and is used to regulate the temperature of the irrigation water flowing through the water supply pipeline. The integrated monitoring module includes multiple soil sensors and a data acquisition device for measuring cultivation substrate parameters; the soil sensors are arranged in a three-dimensional grid in the cultivation substrate inside the main box, and the signal output terminals of the soil sensors are connected to the data acquisition device.

[0007] Preferably, the main housing is made of transparent material, and its side walls are provided with pre-embedded holes for installing the soil sensor.

[0008] Preferably, the temperature-controlled drip irrigation module further includes a water valve and a flow meter installed on the water supply pipeline, as well as a temperature monitoring device for monitoring the temperature of the irrigation water.

[0009] Preferably, the soil sensor is a multifunctional sensor capable of measuring at least one of volumetric water content, temperature, and electrical conductivity.

[0010] Preferably, the system further includes a leachate collection tank, which is located below the drain outlet and is used to collect leachate flowing out of the drain outlet.

[0011] Preferably, the integrated monitoring module further includes a data processing center connected to the data collector.

[0012] Preferably, the insulation layer is a foam insulation layer.

[0013] Preferably, the drainage layer is composed of quartz sand, gravel, or ceramic particles.

[0014] The beneficial effects of this utility model are as follows: This invention constructs an ideal experimental environment for precise variable control. Specifically, the insulation layer structure of the experimental chamber module and the precise temperature control structure of the temperature-controlled drip irrigation module work together to effectively isolate thermal interference from the external environment, providing a stable structural foundation for the study of irrigation water temperature as an independent variable. Simultaneously, the two-dimensional grid arrangement on the surface of the drippers ensures uniform and controllable distributed supply of irrigation water to the cultivation substrate, simulating real-world surface water infiltration conditions and preventing experimental deviations caused by uneven water intake. The integrated monitoring module places multiple soil sensors in a three-dimensional grid inside the chamber. This spatial design allows the system to capture, in situ and synchronously, the dynamic changes of multi-dimensional parameters such as moisture, temperature, and salinity at different locations within the cultivation substrate, providing high-quality data support for revealing the laws governing water, heat, and salt transport.

[0015] This invention provides a standardized, high-precision experimental platform, which is particularly suitable for mechanism research and verification of high-precision CFD models in the field of agricultural water and soil engineering, and provides a powerful tool for optimizing drip irrigation systems. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a temperature-controlled drip irrigation system used for simulating hydrothermal and salt transport in the root zone; In the diagram: 1-Water pump; 2-Water storage unit; 3-Temperature control unit; 4-Water valve and flow meter; 5-Temperature monitoring device; 6-Leachate collection tank; 7-Wing bolt; 8-Drip head; 9-Soil sensor; 10-Water supply pipeline; 11-Main body; 12-Drainage layer; 13-Data acquisition unit; 14-Data processing center. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0018] In the description of this utility model, unless otherwise stated, "multiple" or "several" means two or more. The terms "installation," "connection," and "linking" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model in light of the specific circumstances.

[0019] The accompanying drawings show various structural schematic diagrams according to embodiments of the present invention. These drawings are not to scale, and some details have been enlarged for clarity, while others may have been omitted.

[0020] like Figure 1 As shown, this system is a highly integrated laboratory platform with precise variable control. Through modular and precise structural design, it provides a standardized experimental environment with clear boundary conditions and comprehensive data acquisition for agricultural water and soil engineering research. The entire system consists of three precisely coordinated functional modules: the experimental chamber module, the temperature-controlled drip irrigation module, and the integrated monitoring module.

[0021] The experimental chamber module constructs a container with clearly defined boundaries and a controllable environment for holding the cultivation substrate. It includes a main chamber 11, an insulation system, and a drainage and exudate collection system. The main chamber 11 serves as the main structure, with side walls made of highly translucent acrylic panels, connected by wing bolts 7 for easy disassembly. This design not only provides a direct window for observing the dynamic movement of the internal moist front and root growth and development, facilitating soil sampling and plant root observation, but also ensures the lightweight and robustness of the chamber structure. The chamber is typically a regular cuboid to facilitate subsequent data coordinate calibration and model mesh generation. A high-efficiency insulation layer is tightly wrapped around all outer surfaces of the main chamber as the insulation system. In this embodiment, foam cotton is used, but other insulation materials with extremely low thermal conductivity (e.g., ≤0.05 W / (m·K)) can also be used, such as polyurethane foam or rubber-plastic insulation materials. This structure creates a near-adiabatic thermodynamic boundary, minimizing uncontrolled heat exchange between the cultivation substrate and the external environment. This ensures that the heat input during the experiment primarily originates from the temperature-controlled drip irrigation module, thus making the system's thermal boundary conditions clear and quantifiable. The bottom of the chamber features a specially designed drainage layer of a certain thickness, composed of chemically stable and highly permeable materials such as quartz sand, gravel, or ceramic particles. Drainage outlets are located beneath this layer to ensure that excess irrigation water (leachate) can be smoothly discharged under free drainage boundary conditions. The leachate is guided to a dedicated leachate collection tank 6, allowing for precise calculation of water balance and analysis of solute transport and loss.

[0022] In this embodiment, the cultivation substrate to be studied filled in the main box 11 can be coconut coir, rock wool, etc. The substrate is filled in layers and compacted according to a preset bulk density to ensure the uniformity and repeatability of the experiment.

[0023] The temperature-controlled drip irrigation module is used to precisely regulate the temperature and flow rate of irrigation water. It consists of a water storage unit 2, a water pump 1, and a water supply pipeline 10, forming the basic water circuit. The water pump 1 serves as the power source, pumping water from the water storage unit 2 into the water supply pipeline 10. The irrigation water temperature is modulated through a temperature control unit 3. This modulation is flexible; it can be a standalone external high-precision constant-temperature water bath connected to the system via a circulation pipeline, or a temperature control device integrating a miniature semiconductor cooling chip and heating rod directly into the water storage unit 2. This unit has both heating and cooling functions, capable of adjusting the irrigation water from ambient temperature to any set target temperature. A temperature monitoring device 5, such as a high-precision PT100 temperature sensor, is installed on the water supply pipeline to monitor and provide feedback on the water supply temperature in real time. This, along with the temperature control unit 3, forms a closed-loop control, thereby stabilizing and controlling the fluctuations in irrigation water temperature within a very small range.

[0024] A water valve and flow meter 4 are also installed on the water supply pipeline for precise adjustment and real-time monitoring of irrigation flow. At the end of the water supply pipeline, multiple drippers 8 are evenly arranged in a two-dimensional grid on the upper surface of the main housing 11, with each dripper maintaining a constant flow rate. This planar arrangement aims to simulate uniform irrigation conditions, ensuring uniform water infiltration and providing ideal initial conditions for studying the transport patterns in three-dimensional space. Those skilled in the art can further optimize the dripper structure, for example, by selecting pressure-compensated drippers to further ensure flow stability.

[0025] The integrated monitoring module is used to achieve high-density in-situ data acquisition in three-dimensional space. It is equipped with a three-dimensional sensor array, consisting of a monitoring network of multiple soil sensors 9. These sensors are multifunctional sensors capable of synchronously and in-situ measuring the volumetric moisture content, temperature, and electrical conductivity (EC value, characterizing salt concentration) of the cultivation substrate. Specifically, moisture sensors can be time-domain reflectometers (TDR) or frequency-domain reflectometers (FDR); temperature sensors can be thermocouples or thermistors. The sensors are deployed as follows: before filling the experimental chamber with substrate, sensor probes are inserted into the substrate through specially designed pre-embedded holes on the side wall of the chamber according to a preset three-dimensional grid coordinate system, forming a dense monitoring array at different depths and horizontal positions. The signal output terminals of all sensors 9 are connected to a data acquisition unit 13. The data acquisition unit can automatically and synchronously scan and record the readings of all sensors at user-preset time intervals, such as every 10 minutes. The massive amounts of data collected are uploaded to the data processing center 14 via wired or wireless means. This center is usually a computer with dedicated software installed, which is responsible for data storage, visualization and preliminary analysis. For example, it can generate dynamic curves and 3D cloud maps according to actual needs.

[0026] The aforementioned temperature-controlled drip irrigation system for simulating rhizosphere hydrothermal and salt transport, through precise control of variables and high-density data acquisition, can be used to reveal the influence of irrigation water temperature on rhizosphere hydrothermal and salt transport. The following is an example of studying the effects of different irrigation water temperatures on water and salt transport in coconut coir substrate; the operational steps are as follows: Step 1: System Preparation and Initialization Substrate filling and treatment: First, fill the coconut coir substrate according to the preset bulk density (e.g., 0.1 g / cm³). 3 The substrate is compacted in layers and filled into the main chamber 11 of the experimental module to ensure the uniformity of the matrix and the reproducibility of the experiment. A drainage layer 12 of approximately 3 cm thick quartz sand is pre-laid at the bottom of the chamber. If salt transport needs to be studied, a certain concentration of NaCl solution can be pre-mixed with the coconut coir matrix as a tracer.

[0027] Sensor network deployment: Based on research needs, and following a pre-designed three-dimensional grid coordinate system, the probes of multiple soil sensors 9 are inserted into specific locations in the substrate through pre-embedded holes in the side wall of the housing, constructing a high-density three-dimensional monitoring network. Subsequently, all sensors are connected to the data acquisition unit 13.

[0028] Drip irrigation system installation: Install the drippers 8 at the end of the water supply pipe 10 onto the substrate surface in a two-dimensional grid pattern to ensure that irrigation water is applied evenly. Finally, connect the entire drip irrigation system to the temperature-controlled drip irrigation module.

[0029] Step 2: Setting Experimental Parameters The target irrigation water temperature was set on the temperature control unit 3, including three gradients: 15℃, 25℃, and 35℃, for comparative experiments. Simultaneously, the drip irrigation flow rate was set to 1 L / h via the water valve and flow meter 4, and the total irrigation duration was set to 2 hours. Automatic recording parameters were set on the data acquisition unit 13, recording data from all sensors every 10 minutes.

[0030] Step 3: Experimental Operation and Synchronous Monitoring Start the data acquisition unit 13, and the system will automatically start recording the initial values ​​of each sensor 9.

[0031] The water pump 1 and temperature control unit 3 are started, and the system begins constant temperature drip irrigation. The temperature monitoring device 5 provides real-time feedback on the water temperature to ensure it remains stable at the set value.

[0032] During the experiment, the movement of the wetting front can be observed and recorded directly through the transparent chamber walls. After irrigation, the water pump and temperature control unit are stopped.

[0033] At the end of the experiment, all the leachate was collected into the leachate collection tank 6 through the drain outlet, and its total volume and conductivity (EC value) were accurately measured for water balance and solute loss analysis.

[0034] Step 4: Data Processing and Model Application After the experiment, all spatiotemporal data were exported from Data Processing Center 14. Using specialized software, dynamic curves and distribution cloud maps showing the changes in matrix volumetric water content, temperature, and conductivity over time and space under different water temperature treatments can be plotted. This high-precision, high-resolution spatiotemporal data can be directly used to quantitatively analyze the specific effects of irrigation water temperature on the velocity, range, and intensity of water, heat, and salt transport, and provide reliable experimental evidence for calibrating and validating high-precision numerical models of coupled hydrothermal-salt transport (such as CFD models).

[0035] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A temperature-controlled drip irrigation system for simulating root zone hydrothermal and salt transport, characterized in that, include: The experimental box module includes a main box (11), a drainage layer (12) located at the bottom of the main box (11), and a drainage outlet connected to the drainage layer (12). The main box (11) is used to fill the cultivation substrate, and its outer surface is covered with a heat insulation layer. The temperature-controlled drip irrigation module includes a water storage unit (2), a water pump (1), a temperature control unit (3), a water supply pipeline (10), and multiple drippers (8); the inlet of the water pump (1) is connected to the water storage unit (2), and the outlet is connected in parallel to the multiple drippers (8) through the water supply pipeline (10); the multiple drippers (8) are arranged in a two-dimensional grid on the upper surface of the main body (11); the temperature control unit (3) is set on the pipeline at the outlet of the water pump (1) and is used to adjust the temperature of the irrigation water flowing through the water supply pipeline (10); The integrated monitoring module includes multiple soil sensors (9) and a data acquisition unit (13) for measuring cultivation substrate parameters; the soil sensors (9) are arranged in a three-dimensional grid in the cultivation substrate inside the main box (11), and the signal output terminal of the soil sensors (9) is connected to the data acquisition unit (13).

2. The temperature-controlled drip irrigation system for simulating root zone hydrothermal-salt transport according to claim 1, characterized in that, The main housing (11) is made of transparent material, and its side walls are provided with pre-embedded holes for installing the soil sensor (9).

3. The temperature-controlled drip irrigation system for simulating root zone hydrothermal-salt transport according to claim 1, characterized in that, The temperature-controlled drip irrigation module also includes a water valve and a flow meter (4) installed on the water supply pipeline (10), and a temperature monitoring device (5) for monitoring the temperature of the irrigation water.

4. The temperature-controlled drip irrigation system for simulating root zone hydrothermal-salt transport according to claim 1, characterized in that, The soil sensor (9) is a multifunctional sensor capable of measuring at least one of volumetric water content, temperature and electrical conductivity.

5. The temperature-controlled drip irrigation system for simulating root zone hydrothermal-salt transport according to claim 1, characterized in that, It also includes a leachate collection tank (6), which is located below the drain outlet and is used to collect leachate flowing out of the drain outlet.

6. The temperature-controlled drip irrigation system for simulating root zone hydrothermal-salt transport according to claim 1, characterized in that, The integrated monitoring module also includes a data processing center (14) connected to the data collector (13).

7. The temperature-controlled drip irrigation system for simulating root zone hydrothermal-salt transport according to claim 1, characterized in that, The insulation layer is a foam cotton insulation layer.

8. The temperature-controlled drip irrigation system for simulating root zone hydrothermal-salt transport according to claim 1, characterized in that, The drainage layer (12) is composed of quartz sand, gravel or ceramic particles.

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