A summer maize water and fertilizer integration dynamic regulation method and system based on multi-source data fusion

Abstract

The application provides a summer maize water and fertilizer integration dynamic regulation method and system based on multi-source data fusion, which comprises the following steps: obtaining multi-source monitoring data including soil profile water content, meteorological prediction sequence and growth stage; combining the growth stage and the soil profile water content to calculate the total amount of basic water and fertilizer supply; in the jointing stage and when strong wind is predicted, the total amount of supply is separated into concentrated fertilizer solution and pure water for displacement, the concentrated fertilizer solution is expelled to the deep soil layer by the gravity hydraulic pressure generated by the pure water for displacement after the concentrated fertilizer solution is delivered, and the main root system is forced to grow downward; when high temperature is predicted, batched drip irrigation is performed on the surface soil layer by using pure water, the water infiltration boundary is limited to the inside of the surface layer to perform phase change vaporization to absorb heat, and the conduction of liquid water to the bottom end of the current main root system is blocked; when there is no indication of strong wind trend and no indication of high temperature trend, mixed drip irrigation is performed. According to the meteorological change, the water and fertilizer spatial distribution is reconstructed, and the comprehensive stress resistance of summer maize is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of intelligent irrigation management technology for agricultural water and fertilizer, and in particular to a dynamic regulation method and system for integrated water and fertilizer management of summer maize based on multi-source data fusion. Background Technology

[0002] Summer maize exhibits dynamic changes in its water and nutrient requirements throughout its growth cycle. Integrated fertigation drip irrigation is a commonly used resource supply method in current agricultural production. It primarily relies on the crop's water and fertilizer requirements, mixing soluble fertilizers with irrigation water and delivering them to the crop's root zone. This method effectively meets the crop's metabolic needs under normal climatic conditions and maintains the soil's nutrient levels. In practical applications, conventional drip irrigation typically distributes the fertigation solution relatively evenly in the shallow and middle soil layers. Guided by ambient moisture, the crop's root system tends to develop a lateral network in the shallow surface layer.

[0003] Summer maize plants experience increasing demands on root system physical anchoring strength during specific stages as internodes elongate. When external weather conditions such as strong winds occur, the overturning moment provided by the shallowly distributed root system is relatively limited. Existing irrigation control logic often treats water and fertilizer as a unified whole, rarely considering spatial separation and delivery in light of changing weather conditions. This makes it difficult to use physical means to directionally reconstruct the vertical distribution of fluids, thus leaving room for optimization in actively guiding the taproot system to penetrate deeper into the non-weathered soil layer.

[0004] High temperatures in summer increase the environmental heat load on crops. Existing microclimate cooling irrigation operations typically increase the overall micro-irrigation volume, with liquid water continuously penetrating deep into the taproot zone under the influence of gravitational potential energy. Excess water is difficult to form a lasting heat exchange buffer zone in the shallow soil layer and easily alters the original water-air ratio of the three-phase medium in the rhizosphere. How to dynamically adjust the vertical position of water and fertilizer in the three-dimensional soil profile while meeting basic nutrient transport needs, combined with high temperature or strong wind warnings, is a key technical challenge that needs to be addressed in the field of precision micro-irrigation control. Summary of the Invention

[0005] The purpose of this invention is to provide a dynamic regulation method and system for integrated water and fertilizer management of summer maize based on multi-source data fusion, in order to solve the technical problems of existing conventional integrated water and fertilizer management methods failing to combine meteorological changes to separate and allocate water and fertilizer in the vertical space, resulting in difficulty in actively guiding the main root system to grow deep to resist lodging when encountering strong wind warnings, and difficulty in effectively retaining pure water on the surface for phase change vaporization and cooling in high temperature weather.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A dynamic regulation method for integrated water and fertilizer management of summer maize based on multi-source data fusion includes: Acquire multi-source monitoring data including soil profile moisture content, meteorological forecast sequences, and growth stages; Calculate the total basic water and fertilizer supply by combining the growth stage and the soil profile moisture content; When the growth stage indicates the jointing stage and the weather forecast sequence indicates a strong wind trend, the total basic water and fertilizer supply is separated into concentrated fertilizer solution and pushed pure water; the concentrated fertilizer solution is delivered to the soil until it seeps down to the bottom of the current main root system, and then the pushed pure water, whose volume is calculated based on porosity, is delivered. The gravity hydraulic pressure generated by the pushed pure water is used to push the concentrated fertilizer solution to the deep soil layer below the bottom of the current main root system, forcing the main root system to grow deeper; When the meteorological forecast sequence indicates a high temperature trend, pure water from the total basic water and fertilizer supply is used to perform batch drip irrigation on the surface soil. The water infiltration boundary of each batch of drip irrigation is limited to the interior of the surface soil. The canopy heat is absorbed through phase change vaporization, and the conduction of liquid water to the bottom of the current main root system is blocked. When there is no indication of a strong wind trend or a high temperature trend, mixed drip irrigation shall be implemented according to the total amount of basic water and fertilizer supply.

[0007] Optionally, acquire multi-source monitoring data including soil profile moisture content, meteorological forecast sequences, and growth stages, including: The shallow, middle and deep moisture contents are obtained by using a group of sensor probes buried at various depths in the planting area, and then the soil profile moisture content is generated by merging them. The wind speed forecast and temperature forecast values ​​for the future time window are obtained through a meteorological data interface and combined to generate the meteorological prediction sequence. By retrieving summer maize sowing time records and accumulated temperature evolution data, and comparing them with the standard summer maize growth accumulated temperature model, the growth stage can be determined.

[0008] Optionally, the total basic water and fertilizer supply is calculated by combining the growth stage and the soil profile moisture content, including: Based on the aforementioned reproductive stage, the corresponding daily average evapotranspiration water consumption is extracted, the current radiation data is obtained, and the theoretical water consumption is calculated in combination with the current radiation data. The effective water storage in the soil profile moisture content is extracted, and the water deficit value is obtained by subtracting the theoretical water consumption from the effective water storage. Based on the nutrient requirements corresponding to the growth stage, fertilizer of corresponding quality is allocated to the water deficit value, and the total basic water and fertilizer supply is obtained.

[0009] Optionally, mixed drip irrigation is implemented according to the total basic water and fertilizer supply, including: The total basic water and fertilizer supply is converted into pipeline control flow parameters; The fertilizer injection pump and clean water valve are opened according to the pipeline control flow parameters, and the actual conductivity of the mixed liquid inside the pipeline is continuously monitored. The actual conductivity is compared with the target nutrient solution conductivity to generate a control deviation.

[0010] Optionally, after generating the control deviation, the following steps are also included: The operating frequency of the fertilizer injection pump is dynamically fine-tuned using the aforementioned control deviation. When the actual conductivity falls within the preset conductivity tolerance range, the operating frequency of the fertilizer injection pump is locked until the total amount of basic water and fertilizer supply is delivered.

[0011] Optionally, before conveying the pushed pure water whose volume is calculated based on porosity, the step of calculating the volume is further included: Obtain the vertical distance difference between the bottom of the current main root system and the bottom of the deep soil layer; The vertical distance difference corresponds to the physical porosity and current water saturation within the soil medium layer. The available infiltration volume required to contain the liquid is calculated using the vertical distance difference, the physical porosity, and the current water saturation. The available infiltration volume is converted into water volume and used as the volume of pure water to be moved.

[0012] Optionally, the concentrated fertilizer solution is delivered into the soil until it seeps down to the bottom of the current taproot, followed by the delivery of the pushed pure water, the volume of which is calculated based on porosity, including: Open the fertilizer injection channel to input the concentrated fertilizer solution, and close the fertilizer injection channel when the infiltration front reaches the bottom of the current main root system; The pipeline is kept closed until a preset settling time is reached, allowing the concentrated fertilizer solution to complete lateral capillary diffusion. The pure water is injected into the clear water channel, and the water's own weight fills the shallow pores, creating a downward hydraulic gradient that pushes the concentrated fertilizer solution to settle into the deep soil layer.

[0013] Optionally, before using pure water from the total basic water and fertilizer supply to perform batch drip irrigation on the topsoil, the method further includes: The heat loss required for canopy cooling is calculated based on the difference between the temperature forecast values ​​in the meteorological forecast sequence and the critical heat tolerance temperature of summer maize. Based on the physical constant of latent heat of vaporization, the theoretical total mass of pure water that needs to be evaporated to absorb the lost heat is calculated. Obtain the current pore suction parameters of the surface soil, determine the natural infiltration threshold based on the parameters, divide the total theoretical pure water mass into multiple portions of single pure water injection volume with a mass lower than the natural infiltration threshold, and use these portions as the execution water volume for each batch of drip irrigation.

[0014] Optionally, the water infiltration boundary of each batch of drip irrigation is limited to the interior of the surface soil, absorbing canopy heat through phase change vaporization and blocking the conduction of liquid water to the bottom of the current main root system, including: The drip irrigation batches are triggered sequentially according to a preset time interval; After the water from the previous batch of drip irrigation has completely vaporized, the subsequent batch of drip irrigation is triggered. Maintaining the surface soil moisture content below the critical state that would cause downward gravity seepage, thus preventing liquid water from moving downwards.

[0015] This invention also provides a dynamic regulation system for integrated water and fertilizer management of summer maize based on multi-source data fusion, comprising: The data acquisition module is used to acquire multi-source monitoring data, including soil profile moisture content, meteorological forecast sequences, and growth stages. The basic calculation module is used to calculate the total basic water and fertilizer supply by combining the growth stage and the soil profile moisture content; The hydraulic pushing module is used to separate the total basic water and fertilizer supply into concentrated fertilizer solution and pushing pure water when the growth stage indicates the jointing stage and the weather forecast sequence indicates a strong wind trend; to deliver the concentrated fertilizer solution to the soil until it seeps down to the bottom of the current main root system; and then to deliver the pushing pure water with a volume calculated based on porosity; and to use the gravity hydraulic pressure generated by the pushing pure water to push the concentrated fertilizer solution to the deep soil layer below the bottom of the current main root system, forcing the main root system to grow deeper. The phase change vaporization module is used to perform batch drip irrigation on the surface soil with pure water from the total basic water and fertilizer supply when the meteorological forecast sequence indicates a high temperature trend. It limits the water infiltration boundary of each batch of drip irrigation to the interior of the surface soil, absorbs canopy heat through phase change vaporization, and blocks the conduction of liquid water to the bottom of the current main root system. The mixed drip irrigation module is used to perform mixed drip irrigation according to the total amount of basic water and fertilizer supply when there is no indication of a strong wind trend or a high temperature trend.

[0016] The present invention has achieved the following beneficial effects: The regulation scheme of this invention adaptively adjusts the distribution and positioning of water and nutrients in the vertical space of the soil by combining multi-source monitoring data, taking into account both the basic nutritional needs of summer maize during its daily growth stages and its defense needs under severe weather conditions. In the event of strong winds during the jointing stage, this invention employs a water-fertilizer decoupling and hydraulic displacement mechanism. The downward hydraulic gradient generated by the displacement of pure water forces concentrated nutrients to the deeper soil layers, inducing the main root system to extend and develop towards the lower layers, thus improving the overall physical anchoring performance of the plant. In the face of high-temperature weather warnings, this invention adopts a controlled, batch-based micro-irrigation strategy, confining liquid pure water within the pores of the surface soil. The heat dissipated from the near-surface and canopy is carried away by the phase change of water molecules into a gaseous state, alleviating the high-temperature stress on the crop without disrupting the inherent water-air ratio in the main root area. Under normal climatic conditions, the system smoothly executes mixed drip irrigation, and the overall logic achieves dynamic adaptation between external environmental changes and internal resource supply.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the overall process of a dynamic regulation method for integrated water and fertilizer management of summer maize based on multi-source data fusion, as described in an embodiment of the present invention. Figure 2 This is a flowchart illustrating the steps for acquiring multi-source monitoring data in an embodiment of the present invention; Figure 3 This is a flowchart illustrating the steps of using a hydraulic pushing mechanism to force the main root system to grow downwards in an embodiment of the present invention. Figure 4 This is a flowchart illustrating the steps of absorbing canopy heat and blocking liquid water conduction using phase change vaporization in an embodiment of the present invention. Figure 5 This is a flowchart illustrating the steps involved in the conventional execution of hybrid drip irrigation and its negative feedback fine-tuning process in an embodiment of the present invention. Figure 6 This is a structural diagram of the module composition of the dynamic regulation system for summer maize based on multi-source data fusion in an embodiment of the present invention. Detailed Implementation

[0020] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0021] Reference Figure 1 As shown in the figure, this invention discloses a dynamic regulation method for integrated water and fertilizer management of summer maize based on multi-source data fusion, comprising: Step S11: Obtain multi-source monitoring data including soil profile moisture content, meteorological forecast sequence, and growth stage; Step S12: Calculate the total amount of basic water and fertilizer supply by combining the growth stage with the soil profile moisture content; Step S13: When the growth stage indicates the jointing stage and the weather forecast sequence indicates a strong wind trend, the total basic water and fertilizer supply is separated into concentrated fertilizer solution and pushed pure water; the concentrated fertilizer solution is delivered to the soil until it seeps down to the bottom of the current main root system, and then the pushed pure water with a volume calculated based on porosity is delivered. The gravity hydraulic pressure generated by the pushed pure water is used to push the concentrated fertilizer solution to the deep soil layer below the bottom of the current main root system, forcing the main root system to grow deeper; Step S14: When the meteorological forecast sequence indicates a high temperature trend, pure water from the total basic water and fertilizer supply is used to perform batch drip irrigation on the surface soil. The water infiltration boundary of each batch of drip irrigation is limited to the interior of the surface soil. The canopy heat is absorbed through phase change vaporization, and the liquid water is blocked from being conducted to the bottom of the current main root system. Step S15: If no strong wind trend or high temperature trend is indicated, perform mixed drip irrigation according to the total basic water and fertilizer supply.

[0022] like Figure 2As shown in this embodiment, the data flow and calculation steps of step S11, which involves acquiring multi-source monitoring data including soil profile moisture content, meteorological prediction sequences, and growth stages, are described in detail. Acquiring multi-source monitoring data including soil profile moisture content, meteorological prediction sequences, and growth stages includes: using sensor probe groups buried at various depths in the planting area to acquire shallow, middle, and deep moisture content, and fusing them to generate the soil profile moisture content. It is understood that constructing a continuous water transport gradient along a vertical profile is fundamental to assessing the water-holding capacity of the soil solid medium under the combined influence of gravity seepage and capillary action. Specifically, multiple edge monitoring nodes are deployed within the target planting area, and each edge monitoring node has a set of multi-depth sensor probe groups pre-buried along the vertically downward borehole profile. The sensor probe group includes independent probe sensors based on a frequency domain reflectance monitoring circuit, which are fixed to preset shallow, middle, and deep depth ranges via rigid insulated waveguide rods. The shallow depth range is defined as the space from the surface down to the first depth threshold; the middle depth range is defined as the space between the first and second depth thresholds; and the deep depth range is defined as the space between the second and third depth thresholds. Specifically, based on the water transport characteristics and root distribution patterns of typical loam profiles in the main summer maize producing area of ​​the Huang-Huai-Hai Plain, the first depth threshold is set at 20 cm, the second depth threshold at 40 cm, and the third depth threshold at 60 cm. This depth stratification precisely corresponds to the surface evaporation zone, the main rhizosphere active zone, and the deep water conservation zone of summer maize from jointing to maturity. At each depth, the probe sensors, triggered by a clock interrupt of the microcontroller timer, emit high-frequency electromagnetic pulse waves of a specific frequency into the surrounding three-phase mixed medium of the soil and receive the echo signals reflected along the waveguide component. The phase difference parameters between the emitted and reflected waves are analyzed by the built-in phase detection circuit, and discrete level signals are output via an analog-to-digital converter. The equivalent apparent dielectric constant of the medium surrounding the sensor is then calculated.

[0023] Furthermore, the embedded programs of each edge monitoring node call the pre-stored calibration polynomial equations for the soil bulk density and solid mineral constants of the plot in the system memory to convert the equivalent apparent dielectric constant into a volumetric water content value, thereby obtaining discrete shallow, middle, and deep water contents. Each edge monitoring node encapsulates the discrete water content data and timestamps into a serial communication data frame and uploads it to the central processing unit (CPU) via the fieldbus. The CPU performs filtering and spatial reconstruction processing on the received water content sequence. In the time domain, the CPU calls the Kalman filter algorithm to construct a water content state-space model. This model establishes a state transition matrix for water content between adjacent time steps and an observation matrix characterizing the distribution of measurement errors, and configures system process noise covariance parameters and measurement noise covariance parameters. The state transition matrix is ​​constructed based on the discretization of the one-dimensional Richards flow equation, and the matrix coefficients dynamically map the water conduction flux driven by the current pore matrix potential. The process noise covariance parameter is extracted from the historical discrete variance of the canopy transpiration pull of the previous natural day and assigned a value to quantify the intrinsic uncertainty introduced by the sudden change in the unknown root active water absorption rate; the measurement noise covariance parameter is extracted from the dielectric constant thermal drift coefficient calibrated by the frequency domain reflection sensor probe at the factory, and multiplied with the real-time temperature difference fluctuation of the buried stratum to filter out the pseudo thermal noise interference of the analog circuit caused by the diurnal temperature alternation at the bottom layer.

[0024] In the prediction phase, the algorithm derives the prior state estimate and prior error covariance matrix for the current moment based on the optimal posterior estimate from the previous moment. In the update phase, it incorporates the actual observations fed back by the sensors at the current moment, calculates the Kalman gain matrix, and adjusts the prior estimate to output the posterior state estimate for the current moment. This recursive process runs continuously, filtering out transient high-frequency anomalous data jumps caused by sensor electronic thermal noise and preferential flow in large soil pores. In the spatial dimension, the central processing unit uses the absolute physical burial depth coordinates of each probe sensor as the independent variable and the posterior volumetric water content value after time-domain filtering as the dependent variable. It uses a cubic spline interpolation algorithm under natural boundary conditions to fit and generate a continuous distribution function curve of depth and water content. The algorithm maps the water content distribution between two adjacent depth coordinates to the corresponding cubic polynomial and forcibly applies smooth boundary constraints with continuous function values, first derivatives, and second derivatives at each internal node. It determines the coefficients of each piecewise polynomial by solving a tridiagonal linear equation system using the chasing method. The data matrix corresponding to the distribution function curve is stored as the soil profile moisture content, which is used to characterize the moisture gradient structure model on the longitudinal profile of the soil.

[0025] The system obtains wind speed and temperature forecast values ​​within a future time window through a meteorological data interface and combines them to generate the meteorological forecast sequence. Specifically, the system's network communication module sends data request messages to the remote meteorological data center server via network transport and application layer protocols according to a set internal timer polling frequency. These messages carry the latitude and longitude coordinates of the target planting area. The extracted future time window is set as a preset duration starting from the current physical time. The communication module deserializes and parses the received message payload, extracting the wind speed and temperature forecast values ​​corresponding to each timestamp node using a key-value mapping table. The wind speed forecast values ​​include the average wind speed vector parameter and gust amplitude parameter at the standard altitude plane above the ground; the temperature forecast values ​​include the predicted surface radiation temperature parameter and the predicted dry-bulb temperature parameter of the air above the canopy. Furthermore, the meteorological forecast sequence also simultaneously obtains the predicted relative humidity and atmospheric pressure values ​​of the air above the canopy within the future time window. Temperature and radiation parameters are used to derive the radiation-driven term in the Penman-Monteith equation, while wind speed, relative humidity, and atmospheric pressure parameters are used to derive the aerodynamic drag and vapor pressure differential terms, thereby completing the physical input data stream of the equation. The central processing unit (CPU) performs time-axis alignment on the extracted discrete meteorological physical quantities and uses a piecewise linear interpolation algorithm to calculate the slope and complete the values ​​for time segments missing due to network packet loss, ensuring the continuity of the time series. Subsequently, using the timestamp sequence as the row index, the wind speed forecast numerical sequence is set as the first column vector, and the temperature forecast numerical sequence is set as the second column vector, combining them into a two-dimensional time-series data matrix. This two-dimensional matrix is ​​the meteorological prediction sequence and is cached in dynamic random access memory (DRAM).

[0026] The system retrieves summer maize sowing time records and accumulated temperature evolution data, compares them with the standard summer maize growth accumulated temperature model, and determines the growth stage. Specifically, the central processing unit reads the timestamp of the initial sowing time record from non-volatile memory. Simultaneously, it continuously acquires daily temperature data collected by the weather station via fieldbus and extracts the scalar value of the day's highest temperature. Scalar of lowest temperature The system calculates the effective accumulated temperature for the day using the following nonlinear decay model. And deduct the equivalent of high temperature stress : ; ; ; In the formula, The average daily temperature; This serves as the biological lower limit reference temperature. The upper limit reference temperature for biological applications (calibrated to 35°C); The empirical photosynthetic inhibition coefficient with dimensions (its dimensions are defined as follows): This is used to offset the redundant dimensions caused by the quadratic term, ensuring Output equivalent accumulated temperature (Equivalent) This is the scalar value of the highest temperature of the day; This is the scalar value of the lowest temperature of the day; Equivalent reduction due to high temperature stress; The effective accumulated temperature for the day; This is a truncation comparison operator that takes the maximum value between a conditional value and 0. Time series discrete accumulation is performed to generate accumulated temperature evolution data.

[0027] In this embodiment, considering the physiological characteristics of summer maize, the biological lower limit reference temperature is... The critical heat resistance temperature of the summer maize is calibrated to 10℃. Calibrated at 35℃. Photosynthetic inhibition constant. The value range is set to 0.5 to 0.8, which is the lower limit threshold for the permanent wilting point. The accumulated temperature is set at 10% to 12% based on the soil quality of the planting area. The system database has a pre-built standard growth temperature model for summer maize in the form of a multi-dimensional mapping table data structure. This model discretizes the entire plant growth cycle, establishing a rule base containing lower and upper limits of accumulated temperature closed intervals for each of the seedling, jointing, tasseling, silking, and grain-filling maturity stages. The central processing unit inputs the real-time updated accumulated temperature evolution data as a query key into the model, and uses a binary search algorithm to retrieve the specific closed interval into which the accumulated temperature value falls within the ordered array of accumulated temperature thresholds. The status identifier code bound to this physical interval is extracted and output as the current growth stage.

[0028] As a specific application example, the pre-set rule base in the summer maize standard growth accumulated temperature model includes: a closed interval of [0, 150)℃·d for the seedling stage, [150, 450)℃·d for the jointing stage, [450, 750)℃·d for the large trumpet stage, [750, 1050)℃·d for the tasseling and silking stage, and [1050, 1750]℃·d for the grain-filling and maturity stage. Simultaneously, the system includes built-in nutrient requirement ratios corresponding to different growth stages. The mapping relationship table is as follows: During the jointing stage, the focus is on promoting stem and leaf growth, and its configuration vector is extracted as [0.5, 0.2, 0.3]; During the large trumpet stage, the reproductive growth stage is entered, and its configuration vector is extracted as [0.4, 0.2, 0.4].

[0029] In this embodiment, the steps and formula logic of step S12, which combines the growth stage and the soil profile moisture content, to calculate the total basic water and fertilizer supply are explained in detail.

[0030] Based on the daily average evapotranspiration water consumption corresponding to the aforementioned reproductive stage, current radiation data is obtained, and the theoretical water consumption is calculated using this data. The system calculates the current theoretical water consumption using the following formula. : ; ; In the formula, The reference crop evapotranspiration is obtained using the Penman-Montes equation; The baseline crop coefficient for different growth stages; This represents the initial average daily evapotranspiration water consumption; This is a dimensionless adjustment factor for evaporation depth based on net radiation. The physical area constant of the control region; This represents the theoretical water consumption calculated. In this embodiment, the benchmark crop coefficients for different growth stages are used as the physiological baseline for summer maize in the Huang-Huai-Hai region. The specific values ​​are: 0.70 at the seedling stage, 1.20 at the jointing stage, 1.25 at the tasseling and silking stage, and reduced to 0.90 at the grain-filling and maturity stage. The adjustment coefficients are... The computational formula is reconstructed as ,in This represents the current transient net radiation flux density obtained from meteorological data. To correspond to the historical reference net radiation flux density benchmark value within the meteorological cycle, the system uses this dimensionless ratio to eliminate radiation-driven errors under meteorological abrupt changes.

[0031] The available water stock is extracted from the soil profile moisture content, and the water deficit is obtained by subtracting the theoretical water consumption from the available water stock. The available water stock can be extracted using capillary osmosis. and water deficit values The definite integral calculation model is as follows: ; ; In the formula, and These are the upper and lower boundaries of the current main root system's residence depth range, respectively; For depth The continuous moisture content distribution function at a given location; This is the lower threshold for the point of permanent wilting. This is a conditional truncation comparison operator used to remove invalid water partition blocks; The physical area constant of the control region; Vertical depth is the independent variable; Effective water storage; This represents the theoretical water consumption. This represents the water deficit value.

[0032] Based on the nutrient requirement ratio corresponding to the growth stage, fertilizer of corresponding mass is allocated to the water deficit value, and the total basic water and fertilizer supply is obtained. The system constructs a full-rank coefficient matrix, introduces the target nutrient solution concentration benchmark, and accurately solves the linear equations for the physical absolute mass of fertilizer for each entity as follows: ; In the formula, column vector These represent the physical mass of urea, diammonium phosphate, and potassium sulfate, respectively, when applied as solid fertilizers. The calculated water deficit volume; The system's pre-set target nutrient solution total baseline design concentration (unit: ); This is a dimensionless nutrient requirement vector representing the proportions of total nitrogen, available phosphorus, and available potassium; elements To correspond to the dimensionless effective mass fraction of nutrients in solid fertilizers, off-diagonal elements are forcibly loaded with chemical cross-coupling terms of dissociated associated elements.

[0033] Specifically, elements Representing the The nutrient elements (corresponding to the nitrogen, phosphorus, and potassium sequences) in the first... The effective mass fraction of each type of fertilizer (corresponding to the sequences of urea, diammonium phosphate, and potassium sulfate). The full-rank coefficient matrix parameters used in this embodiment are: urea provides only nitrogen (main term). 0.46, off-diagonal term 0、 0); Diammonium phosphate (DAP) provides available phosphorus as the main element while simultaneously releasing total nitrogen, forming a forced cross-coupling term (cross-coupling term) 0.18, primary item 0.46, off-diagonal term 0); Potassium sulfate only provides readily available potassium (non-diagonal items). 0、 0, main item 0.50). The system uses this to establish a full-rank linear equation system to solve for the material feeding mass. The physical absolute mass parameters of each fertilizer and the pure water volume parameters corresponding to the moisture deficit value are serialized and encapsulated, and combined to generate a control instruction parameter package. This parameter package is the total amount of basic water and fertilizer supply, and is then pushed into the system execution cache.

[0034] like Figure 5 As shown in this embodiment, the physical execution process and negative feedback mechanism of mixed drip irrigation when neither a strong wind trend nor a high temperature trend is indicated in step S15 are described. Mixed drip irrigation is executed according to the total basic water and fertilizer supply, including: converting the total basic water and fertilizer supply into pipeline control flow parameters; opening the fertilizer injection pump and clear water valve according to the pipeline control flow parameters, continuously monitoring the true conductivity of the mixed liquid inside the delivery pipeline; comparing the true conductivity with the target nutrient solution conductivity to generate a control deviation. Specifically, the control processor extracts the water volume parameters and fertilizer quality parameters encapsulated in the total basic water and fertilizer supply, and calculates the baseline clear water flow velocity of the main pipeline and the baseline injection flow rate of the fertilizer injection branch by combining a preset single-round irrigation time window. Combining the pipeline cross-sectional area parameters and fluid dynamics equations, the flow data is mapped and converted into pipeline control flow parameters that drive the opening degree of the electromagnetic main valve and the operating frequency of the water pump inverter. The underlying electromechanical execution unit receives the pipeline control flow parameters, and the digital-to-analog conversion unit outputs the corresponding pulse width modulation signal to drive the relay to open the clean water solenoid main valve and start the frequency converter of the fertilizer injection pump. The clean water fluid and fertilizer mother liquor undergo physical mixing in the mixing chamber. An online conductivity sensor probe, located downstream of the mixing section of the main pipeline, detects the conductivity of free ions in the medium solution in real time. The sensed signal is amplified and converted from analog to digital to generate digitized real conductivity data. The processing unit retrieves the target nutrient solution conductivity benchmark value pre-calculated based on the fertilizer quality configuration, and sends the collected real conductivity and the target nutrient solution conductivity to the differential logic unit for subtraction. The difference between the two values ​​is recorded and updated as the control deviation.

[0035] After generating the control deviation, the system further includes: dynamically fine-tuning the operating frequency of the fertilizer injection pump using the control deviation; locking the operating frequency of the fertilizer injection pump when the actual conductivity falls within a preset conductivity tolerance range, until the total supply of basic water and fertilizer is completed. The logic for determining whether the actual conductivity falls within the preset conductivity tolerance range incorporates a pure time lag compensation mechanism based on the physical characteristics of the pipeline network. The control engine retrieves the physical pipe section length parameter between the fertilizer injection mixing chamber and the conductivity sensor probe, divides it by the real-time clear water flow rate of the main line, and calculates the pure time lag required for fluid displacement transmission. The system sets ±3% of the target nutrient solution conductivity value as the physiologically permissible fluctuation dead zone. Only when the actual conductivity continuously falls within this dead zone and the duration of this sustained period is greater than 1.5 times the pure time lag dead zone, does the system confirm that the pipeline fluid mixing has reached a spatial dynamic steady state, and then sends a frequency locking control word to the fertilizer injection pump inverter to lock the operating frequency until the total supply of basic water and fertilizer is completed. This eliminates the mechanical fatigue and water hammer effect caused by frequent reactive frequency changes in the pump impeller.

[0036] The system uses a proportional-integral-derivative (PID) algorithm to generate the adjustment frequency parameters for the fertilizer injection pump. The formula is: ; In the formula, For the first The frequency adjustment increment of the fertilizer injection pump in each sampling cycle; , , These represent the differences between the actual conductivity and the target conductivity for the current, previous, and two previous sampling periods, respectively. , , These are proportional linear gain, discrete integral compensation, and differential control constant, respectively. This is the sampling period duration. The current absolute frequency is given by the equation... Iterative update, where, For the current (number) The operating frequency of the fertilizer injection pump in each sampling cycle; For the previous (the first) The operating frequency of the fertilizer injection pump during each sampling cycle.

[0037] To ensure the dynamic convergence of the conductivity control loop in a pure time-delay environment within a water-fertilizer mixing network, the proportional linear gain... Discrete integral compensation With the differential constant of reverse damping It is obtained by pre-tuning using the critical proportional gain method (Ziegler-Nichols method) in the hydraulic calibration test of the pipeline network. Specifically, in this embodiment, the range of PID control coefficient values ​​is selected as follows: The value should be between 1.2 and 2.5, preferably 1.8; The value should be between 0.05 and 0.15, preferably 0.08; The value is between 0.1 and 0.3, preferably 0.15. This set of parameters, combined with the aforementioned locking mechanism of 1.5 times pure time lag, achieves rapid response and overshoot suppression for the fertilizer injection pump frequency adjustment. If the control deviation is positive, the algorithm generates a negative frequency gain command to reduce the operating frequency of the fertilizer injection pump and decrease fertilizer injection; if the control deviation is negative, a positive frequency gain command is generated to increase the operating frequency of the fertilizer injection pump. The system cyclically executes a closed-loop negative feedback process of frequency fine-tuning and fluid conductivity sampling at a set clock cycle. When the control deviation enters the preset conductivity tolerance range for multiple consecutive sampling cycles, the control engine sends a frequency lock control word to the fertilizer injection pump inverter, and the fertilizer injection pump maintains a constant output at the current operating frequency. An electromagnetic flow totalizer installed on the pipeline trunk line accumulates pulse counts of the total fluid volume. When the hardware counter detects that the accumulated total volume value matches the pure water volume limit set in the total basic water and fertilizer supply, the main control unit sends an interrupt signal to the output board, cuts off the power supply circuit of the actuator of the external solenoid valve and the water pump, and terminates the mixed drip irrigation process.

[0038] like Figure 3 As shown, this embodiment describes the physical process and control logic of separating water and fertilizer and guiding the main root system downwards in a three-dimensional soil profile using a hydraulic pushing mechanism in step S13. When the growth stage indicates the jointing stage and the weather forecast sequence indicates a strong wind trend, the total basic water and fertilizer supply is separated into concentrated fertilizer solution and pushed pure water. Specifically, the central processing unit continuously reads the growth stage identifier and weather forecast data matrix from the status register. When it is determined that the current stage is the jointing stage and the wind speed forecast scalar exceeds the preset safety threshold, the processor triggers the deep pushing defense branch code. The preset safety threshold is solved inversely from the balance model of the plant's dynamic overturning moment and the ultimate pull-out resistance moment: ; When overturning moment When (lift resistance moment) is calculated, the critical wind speed can be obtained. In the formula, air density; This refers to the drag coefficient; The projected area facing the wind; The height of the lever arm; This refers to the dynamic overturning moment of the plant. This is the critical wind speed.

[0039] Among them, the pull-out resistance moment Real-time dynamic calculations were performed using an empirical model for soil stabilization based on root-soil composites. ; In the formula, The soil shear strength is calculated by the system using the current deep water content and preset soil bulk density parameters, based on the Mohr-Coulomb criterion. The specific conversion formula is as follows: In the formula, The effective normal stress is calculated by integrating the pre-set dry soil density by the depth. Obtained from gravitational acceleration; Current volumetric moisture content Soil cohesion below, Current volumetric moisture content The internal friction angle is calculated using an empirical attenuation model. and ,in and These represent the cohesive force and internal friction angle of the base after curing in the dry state, respectively. and The system's built-in exponential decay fitting coefficient based on regional soil mechanics calibration; This is a natural constant. The soil mechanics calibration of the region is obtained by extracting the envelope through standard triaxial shear tests (CU / UU tests) at multiple moisture contents on typical undisturbed soil samples from the Huang-Huai-Hai Plain. In this embodiment, for the medium loam medium within the target planting area, the basic cohesion is... The calibrated value is 25.0 kPa, and the internal friction angle of the foundation is... The calibration value is 30°. Meanwhile, the exponential decay fitting coefficient characterizing the moisture softening effect is specifically calibrated as: cohesion decay coefficient. The value is 3.1, which is the attenuation coefficient of the internal friction angle. The value is set to 1.2. This set of solidification parameters ensures that the system can accurately calculate the real-time shear capacity of the soil based on the real-time dynamic moisture content, avoiding calculation divergence in the pull-out resistance moment. This is the equivalent diameter of the current main root crown. This represents the current depth of the main root system. The anchorage reduction factor is based on long-term field lodging resistance tensile test data in the Huang-Huai-Hai region, and its value ranges from 0.35 to 0.45. This is to resist the pull-out resistance torque.

[0040] In addition, the plant physical parameters (drag coefficient) required for calculating the dynamic overturning moment of the plant are also needed. Windward projection area lever arm height Instead of real-time visual measurement, the morphological evolution curve of summer maize is obtained by retrieving a pre-set curve within the system. This curve is based on a non-linear logistic regression relationship between the aforementioned accumulated temperature evolution data and plant morphology. The system substitutes the currently accumulated temperature evolution data into the regression equation to directly look up the corresponding data or calculate and output the corresponding curve. and Estimated value.

[0041] The specific mathematical equation for the nonlinear Logistic regression relationship is uniformly expressed as follows: ; In the formula, Generally refers to the specific morphological scalar quantity of the plant that needs to be estimated (representing the windward projected area). lever arm height The current equivalent diameter of the main root crown. Or the current depth of the main root system ); This represents the biological asymptotic maximum that this morphological scalar can reach during the jointing to maturity stage; This represents the current cumulative effective temperature. The morphogenesis rate constant, This is the temperature-sensitive drive control constant; It is a natural constant; This represents the soil shear strength at the current moisture content. This represents the current volumetric moisture content. The system has preset corresponding values ​​for each. Multiple groups A feature parameter library is provided for the arithmetic unit to use. Specifically, the values ​​in the feature parameter library are based on years of field phenotypic observation data of mainstream varieties (such as Zhengdan 958) in the main summer maize producing areas of the Huang-Huai-Hai Plain, and are obtained by fitting model parameters using the nonlinear least squares method. In this embodiment, the values ​​corresponding to each morphological scalar are ( , , The characteristic parameters are set as follows: for the windward projected area Biological asymptotic maximum Take 0.35 m², morphogenesis rate constant Take 5.5 as the accumulated temperature sensitive drive control constant. Take 0.008; for lever arm height , Take 1.35m, Take 5.0, Take 0.007; for the current equivalent diameter of the main root crown. , Take 0.45m, Take 4.8, Take 0.006; for the current root system retention depth , Take 0.70m, Take 4.5, The value is set to 0.005. By solidifying the above parameter matrix, the system can directly convert the accumulated effective temperature into a high-precision plant stress structure reference.

[0042] The safe wind speed threshold is: ; In the formula, To prevent lodging, a reduction factor (value between 0.80 and 0.85) is applied. The safe wind speed threshold; This is the critical wind speed. Once the predicted wind speed exceeds this mechanically critical boundary, it indicates a surge in the risk of shallow root anchoring failure, necessitating the triggering of a deep root migration intervention command. The processor performs a deconstruction operation on the basic water and fertilizer supply total data packet, isolating and encapsulating the total fertilizer mass parameters. The arithmetic comparator calculates the lower limit scalar value of the liquid phase volume, balancing anti-crystallization and physiological safety. The envelope equation is: ; In the formula, This refers to the total mass of fertilizer. Water temperature The maximum solubility at that level; 0.95 is the safety margin; This refers to the total molar amount of fertilizer. The maximum molar concentration limit to prevent reverse water loss from the roots; This is the lower limit scalar value for the liquid phase volume; The temperature of deep soil water; A mathematical comparison operator that takes the maximum value among the results of multiple operations. The maximum molar concentration limit. The calculation is derived based on van't Hoffequation: ,in The limit of osmotic pressure for the main root system of summer maize to withstand physiological drought (in this embodiment, it is calibrated to 0.8 MPa in conjunction with the drought resistance index of summer maize in the Huang-Huai-Hai Plain). The average van der Hoff dissociation factor of the mixed fertilizer solution. Let be the ideal gas constant. This represents the absolute temperature of the current deep soil layer. This is the maximum molar concentration limit. Based on this, calculations will be performed... The concentration is forcibly constrained within the range of 0.12 mol / L to 0.15 mol / L as a rigid constraint condition for the system. The maximum value between the two is directly assigned as the lower limit scalar value of the liquid phase volume. The water volume corresponding to this lower limit scalar value is used as the solvent and recombined with the total fertilizer mass parameter. The output command drives the fertilizer mixing execution mechanism to generate a concentrated fertilizer solution with the corresponding configuration ratio. The calculation module subtracts the above-mentioned lower limit scalar value of the liquid phase volume from the original total water volume parameter in the basic water and fertilizer supply, and stores the remaining volume value as an execution variable.

[0043] Before conveying the pushed pure water based on the porosity-calculated volume, the process further includes a volume calculation step: obtaining the vertical distance difference between the bottom of the current main root system and the bottom of the deep soil layer; detecting the physical porosity and current water saturation within the soil medium layer corresponding to the vertical distance difference; and calculating the available infiltration volume required to contain the liquid using the vertical distance difference, the physical porosity, and the current water saturation. To compensate for the solute fingering effect caused by preferential flow through large pores and hydrodynamic dispersion in heterogeneous farmland soils, and to avoid excessive displacement of nutrients to deep, ineffective spaces, a hydrodynamic dispersion correction coefficient is introduced. The spatial constraint equation for the available infiltration volume (i.e., the volume of pushed pure water) required to contain the liquid is then modified as follows: ; In the formula, Available volume for displacement; The current water saturation level, Characterizes the porosity; Physical porosity; This represents the difference in vertical distance. To control the area constant; This is a hydrodynamic dispersion correction coefficient. This coefficient is calibrated based on the heterogeneity of soil pore distribution in the planting area. For the typical loam soil structure of the Huang-Huai-Hai Plain, its value is set to range from 0.85 to 0.90 to compensate for the pushover error generated by the ideal piston flow model in actual soil media. The processor converts the available infiltration volume into water volume, which is then used as the volume of the pushed pure water, forming a more rigorous physical constraint setting on the input amount of the push medium.

[0044] The concentrated fertilizer solution is delivered to the soil until it infiltrates to the bottom of the current main root system. Subsequently, the volume of the pushed pure water, calculated based on porosity, is delivered. This process includes: opening the fertilizer injection channel to input the concentrated fertilizer solution; closing the injection channel when the infiltration front reaches the bottom of the current main root system; maintaining the pipeline closed until a preset settling time is achieved, allowing the concentrated fertilizer solution to complete lateral capillary diffusion; and opening the clear water channel to inject the pushed pure water, using the water's own weight to fill shallow pores and create a downward hydraulic gradient, propelling the concentrated fertilizer solution to settle into the deeper soil layer. Specifically, the control unit outputs a control level to the external drive circuit, closing the main clear water valve of the main pipeline and activating the solenoid valve and booster pump of the fertilizer injection channel. The concentrated fertilizer solution infiltrates and moves downwards along the pores. The processor reads the conductivity sensor sampling parameters at the corresponding depth at the bottom of the current main root system at a fixed clock cycle. When a positive step change in conductivity is detected, and the slope of the change triggers a preset condition, the control unit outputs an interrupt signal, disconnecting the control relay link of the fertilizer injection booster pump and the solenoid valve, thus stopping fluid output. The condition is met using a digital signal differential algorithm based on a sliding time window. The system caches discrete conductivity data from five consecutive sampling periods to form a sliding time window. A digital differentiator is used to calculate the arithmetic mean of the first-order differences between adjacent sampling points, thus characterizing the transient slope. A logic comparator constrains this slope to remain positive, and the absolute value of the conductivity in the latest period must exceed the arithmetic sum of the background conductivity of the formation at that depth under non-piped water injection conditions and three times the standard deviation of the sensor's thermal noise. Meeting this composite condition confirms that the high-concentration nutrient ion front has substantially contacted and penetrated the current main root basal interface.

[0045] The control system then activates the timer module to maintain the pipeline valves in a closed state for a preset settling time. During this period, the concentrated fertilizer solution within the pore channels loses the externally applied hydrostatic thrust. Under the influence of the matrix potential difference on the soil particle surface, the fluid undergoes lateral capillary diffusion along the horizontal pore network, spreading at the solid-phase interface to form a laterally extended concentration zone. The inversion formula for the characteristic relaxation time (i.e., the preset settling time) of the lateral spread of the concentrated fertilizer solution is: ; In the formula, The characteristic relaxation time; Specify the spacing for the drip irrigation system. Characterizes the radiation radius; The effective apparent diffusion coefficient. The determination relies on standard breakthrough curve experiments for soil solute transport. Regarding the lateral capillary transport characteristics of soluble compound fertilizers (such as a mixture of nitrate nitrogen and available potassium) in loam matrices with a porosity of 40% to 45%, this embodiment uses the system memory to... Fixed assignment value m² / s. Substituting this benchmark into the characteristic relaxation time inversion formula, the optimal preset settling time matching the current dripper spacing can be automatically calculated to ensure the continuity of the chemical induction zone. The system directly writes this characteristic relaxation time scalar into the timer as the preset settling time, ensuring that the high-concentration fertilizer solution can withstand the vertical hydraulic displacement of pure water after establishing a complete chemical induction zone in the lateral network. When the timer accumulates to the preset settling time, the processor releases the control lock of the pipeline network, opens the clear water channel and pressurization equipment, and injects pure water with a constant pressure into the surface with the assigned limit parameter. The pure water fills the empty pore network of the shallow and middle soil layers. As the medium tends to saturate, free water occupies the pore space, and the soil matrix suction parameter decreases. The self-weight stress of the fluid and the pore water pressure accumulate vertically, constructing a vertically downward hydraulic gradient physical field on the macroscopic vertical profile. This gravity-hydraulic vector acts directly on the interface of the concentrated fertilizer solution layer, overcoming the interface friction resistance and fluid viscous shear force, and driving the concentrated fertilizer solution to undergo forced vertical displacement and sedimentation. When all the pure water is consumed, the concentrated fertilizer solution remains in the pre-defined deep soil layer. The high concentration of nutrients in this deep space alters the vertical distribution, inducing the taproot to develop into the deeper, non-weathered soil layer through chemical potential, thereby improving the overall lodging resistance of the plant.

[0046] like Figure 4 As shown in this embodiment, the phase change vaporization control logic and energy constraint calculation in step S14 are explained in detail. When the meteorological forecast sequence indicates a high temperature trend, pure water from the total basic water and fertilizer supply is used to perform batch drip irrigation on the surface soil. The water infiltration boundary of each batch of drip irrigation is limited to the interior of the surface soil. The phase change vaporization absorbs the canopy heat and blocks the conduction of liquid water to the bottom of the current main root system. It can be understood that by utilizing the latent heat absorption characteristic of water molecules when they change from liquid to gas, water is fixedly retained on the surface heating surface. Convection is established by absorbing the sensible heat of the environment through phase change, and the microclimate heat load can be regulated. Before using the pure water from the total basic water and fertilizer supply to perform batch drip irrigation on the surface soil, the process includes: calculating the heat loss required for canopy cooling based on the difference between the temperature forecast value in the meteorological forecast sequence and the heat tolerance critical temperature of summer maize; estimating the theoretical total mass of pure water that needs to be evaporated to absorb the heat loss based on the physical constant of latent heat of vaporization; obtaining the current pore suction parameter of the surface soil, and determining the natural infiltration threshold based on this parameter; dividing the theoretical total mass of pure water into multiple single pure water injection volumes with masses lower than the natural infiltration threshold, which serve as the execution water volume for each batch of drip irrigation. Specifically, the central processing unit scans the meteorological forecast sequence matrix and extracts the highest ambient temperature forecast value within the time window. It reads the heat tolerance critical temperature of summer maize from the read-only storage area and performs a subtraction operation to obtain the absolute temperature difference parameter. The heat loss that needs to be dissipated to absorb heat is also considered. and the corresponding theoretical total mass of pure water evaporated. The thermodynamic model is as follows: ; ; In the formula, These are the dry air density and the specific heat capacity constant at constant pressure, respectively. The equivalent air volume of the canopy. Through formula Dynamic calculation. Among them, The equivalent land surface area allocated to a single summer maize plant within the control area; The current lever arm height is obtained using the aforementioned accumulated temperature model; The current leaf area index is estimated based on accumulated temperature; This is the maximum leaf area index constant for this variety under ideal conditions; This is the equivalent air volume of the canopy. This formula precisely isolates the physical space occupied by the plant body and outputs the effective air volume that can exchange sensible heat with gaseous water molecules. Forecast of maximum temperature; This refers to the critical temperature for heat resistance of summer maize. The latent heat of vaporization of water is denoted as . The heat that needs to be dissipated to cool the canopy; The theoretical total mass of pure water that needs to be evaporated to absorb the lost heat.

[0047] The processor acquires matrix potential and matrix suction sensor feedback parameters buried in the very shallow surface layer through the acquisition channel. Based on the unsaturated seepage equation, under the influence of gravitational water potential and matrix water potential, it calculates the upper limit of the single liquid water holding capacity of the micro-pore network per unit control area under the current pore suction constraint background condition, where the downward gravitational component is insufficient to cause displacement and settlement. This is set as the natural infiltration threshold. The solution to this natural infiltration threshold is anchored to the critical equilibrium state of the forces within the surface soil micro-element. The computational kernel extracts the geometric thickness micro-element and real-time volumetric water content of the very shallow surface layer, and substitutes them into the soil moisture characteristic curve to calculate the matrix suction head vector pulling upward on the pore network. A one-dimensional hydraulic equation is constructed, such that the absolute values ​​of the gravitational potential energy vector excited by the batch injection of pure water and the matrix suction head vector are in a suspended state of algebraic cancellation. Specifically, the solution to the natural infiltration threshold is based on the unsaturated soil moisture characteristic curve (such as the van Genuchten model) to construct the micro-element force equilibrium equation: ; In the formula, To utilize the real-time volumetric water content of extremely shallow surface layers The obtained pore matrix suction head (with the dimension of length, representing the upward capillary water-holding height limit) is calculated by the system based on the van Genuchten unsaturated water characteristic model. The specific formula is as follows: ; In the formula, The saturated volumetric water content of the very shallow surface medium; This refers to the residual volumetric moisture content. The real-time volumetric water content of the very shallow surface layer is fed back by the sensor probe. Physical calibration constant (unit: ) that is inversely proportional to soil air intake value or ); A dimensionless index that reflects the characteristics of pore size distribution; This refers to the suction head of the porous matrix. The system has built-in calibration parameters for typical loam habitats in the Huang-Huai region: , , , By real-time By substituting the values, we can obtain the dynamically changing matrix water-holding head index with length dimensions.

[0048] This represents the limiting equivalent water layer thickness element when the water infiltration boundary just fails to breach the surface structure. The maximum equivalent water layer thickness at this point is calculated. Multiplying this by the single drip irrigation control area and physical porosity yields the ultimate suspended liquid water volume corresponding to the point where the force returns to zero.

[0049] After converting the volume to mass, a safety reduction factor of 0.9 is applied to avoid downward leakage caused by preferential flow through large pores, ultimately solidifying the output as the natural infiltration threshold. This fundamentally cuts off the channel for water to conduct heat to the root zone through capillary action. The control program initiates a data splitting algorithm, dividing the theoretical total mass of pure water into multiple discrete data packet combinations. Comparison logic circuits verify the mass value corresponding to each data packet, ensuring it is strictly below the natural infiltration threshold. Verified data packets are sequentially pushed into the execution stack of memory, serving as the single pure water injection volume and constituting the parameters of the drip irrigation command.

[0050] The system limits the infiltration boundary of each batch of drip irrigation to within the surface soil. It absorbs canopy heat through phase change vaporization and blocks the conduction of liquid water to the bottom of the current main root system. This includes: triggering each batch of drip irrigation sequentially at preset time intervals; detecting that the water from the previous batch has completely vaporized before triggering subsequent batches; and maintaining the surface soil moisture content below the critical state for downward gravity seepage, thus preventing liquid water from moving downwards. Specifically, the central control scheduling unit extracts the injection volume command parameters for the first batch from the execution stack and sends a conduction level to the solenoid valve of the control node. Because the single-volume flow is limited by the natural infiltration threshold, the gravitational potential energy generated after liquid water seeps into the surface is completely offset by the matrix suction of the unsaturated solid particles. The downward leading edge of the water is locked within the surface cross-section. Liquid water molecules residing in the porous framework on the surface absorb short-wave radiation energy from the environment and sensible heat from the near-surface air. As their internal molecular kinetic energy increases, they break through the surface tension of the liquid phase and escape as gaseous water vapor, completing latent heat exchange and generating convective heat transfer.

[0051] After a single micro-water injection, the central processing unit initiates a cyclic reading process, scanning the monitoring signals from the surface medium moisture content detection sensor. As the vaporization phase change occurs, the surface volumetric moisture content reading exhibits a monotonically decreasing curve. The digital differentiator in the arithmetic module performs first-order derivative calculations on the continuously decreasing curve. When the comparison control logic determines that the current transient moisture content value has fallen back into the error band of the initial reference interval before water injection, and the absolute value of the calculated first derivative approaches zero constant, it is determined that the liquid water trapped in the surface space has completely undergone a physical transformation to a gaseous state. After capturing this verification determination state, the system releases the execution stack pointer's lockout, extracts the next instruction data packet in the sequence, and triggers the execution of the next batch of drip irrigation commands. This feedback verification process constructs a closed-loop trigger condition, maintaining the total integral value of the liquid phase moisture remaining in the surface soil below the critical saturation point that triggers continuous gravity seepage. Geometrically, this cuts off the hydraulic channel for the liquid medium to migrate to the bottom of the current main root system, ensuring the independent phase change function of the trapped water.

[0052] like Figure 6As shown, this invention also discloses a dynamic regulation system for integrated water and fertilizer management of summer maize based on multi-source data fusion, used to execute the dynamic regulation method for integrated water and fertilizer management of summer maize based on multi-source data fusion described in any of the preceding embodiments. The regulation system integrates a physical architecture including: a data acquisition module for acquiring multi-source monitoring data including soil profile moisture content, meteorological forecast sequences, and growth stages; a basic calculation module for calculating the total basic water and fertilizer supply by combining the growth stage and the soil profile moisture content; and a hydraulic pushing module for separating the total basic water and fertilizer supply into concentrated fertilizer solution and pushed pure water when the growth stage indicates the jointing stage and the meteorological forecast sequence indicates a strong wind trend; delivering the concentrated fertilizer solution to the soil until it infiltrates to the bottom of the current main root system, and then delivering the pushed pure water with a volume calculated based on porosity, utilizing... The gravity hydraulic pressure generated by the pushing of pure water forces the concentrated fertilizer solution to the deep soil layer below the bottom of the current main root system, forcing the main root system to grow downwards; the phase change vaporization module is used to perform batch drip irrigation on the surface soil using pure water from the total basic water and fertilizer supply when the weather forecast sequence indicates a high temperature trend, limiting the water infiltration boundary of each batch of drip irrigation to the interior of the surface soil, absorbing canopy heat through phase change vaporization, and blocking the conduction of liquid water to the bottom of the current main root system; the mixed drip irrigation module is used to perform mixed drip irrigation according to the total basic water and fertilizer supply when neither a strong wind trend nor a high temperature trend is indicated.

[0053] At the system hardware topology and communication data flow level, the data acquisition module is configured with an embedded industrial data acquisition and communication gateway processing device and a multi-channel analog-to-digital converter integrated circuit. The external physical port of the acquisition gateway is cascaded with a frequency domain reflection sensor array buried in the soil stratification space via a serial communication bus. The gateway uses a polling protocol based on its built-in address mapping table to extract the dielectric constant and temperature characteristic level signals of each node. Internally, the module connects to a remote meteorological data server cluster via an Ethernet control chip and network protocol stack to extract forecast message data. The acquired analog signals are passively low-pass filtered and converted to digital, then timestamped and mapped into a dual-port static random access memory array after combining the network message parsing data. The logic code segment of the basic calculation module is fixed in the read-only memory sector of the main control microprocessor. The processing core reads the parameter matrix in the storage medium via the system address bus. It calls the arithmetic logic unit and floating-point coprocessor to execute the unsaturated seepage equation and algebraic formula transformation. The calculated fluid volume and solute mass scalars are encapsulated as control instruction parameter packets and pushed into the system buffer register queue.

[0054] The hydraulic push module and phase change vaporization module are controlled by a hardware interrupt identification circuit and a drive controller in terms of control architecture. The hydraulic push module has a built-in clock timing generator circuit. When the internal event comparator detects that the wind force over-limit status indicator and the jointing period indicator are set simultaneously, it sends an interrupt signal to take over the bus control authority. The drive distribution circuit reads the volume configuration parameters, generates a pulse width modulation signal, changes the input voltage and power of the fertilizer injection pump motor, and controls the on / off state of the solenoid valve coil. The clock circuit provides a physical lockout delay time window for the static blocking state. After the delay ends, the clean water power pump is activated to perform constant pressure delivery displacement action. The phase change vaporization module has built-in energy transfer dissipation digital algorithm code firmware and is equipped with a multi-channel analog-to-digital interface to collect the dynamic level feedback from the surface moisture content probe. The module integrates voltage comparator circuit logic to compare the attenuation level with the set reference background threshold. When the first derivative calculation signal satisfies the zero-crossing level flip, the edge triggers the system interrupt response, sends a micro-drip irrigation control command for the execution time segment to the external power relay, and constructs a closed-loop verification link.

[0055] The hybrid drip irrigation module employs a digital processing kernel incorporating a proportional-integral-derivative (PID) control algorithm. A pre-deployed operational amplification differential matching network conditions the conductivity analog signal captured by the main flow cross-section probe. An analog-to-digital converter quantizes the signal and sends it to the algorithm kernel, which performs differential calculations between the transient data and the target parameters. By proportionally amplifying the error amplitude, accumulating discrete integrals, and performing differential calculations on high-frequency slope variations, the output frequency setting offset is calculated. This offset instruction data is written into the frequency configuration address of the AC servo motor drive control integrated chip, dynamically adjusting the fertilizer injection pump output power. A correction mechanism automatically offsets flow velocity interference caused by frictional resistance in the water supply network and dynamic pressure fluctuations, maintaining the physical uniformity of the ion concentration in the system's output mixed fluid. Each hardware application unit is dispatched and executed by an industrial task scheduling processor, achieving a fully automated closed-loop control architecture from sensor parameter perception and logical operation output to terminal electromechanical servo drive actions.

[0056] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A dynamic regulation method for integrated water and fertilizer management of summer maize based on multi-source data fusion, characterized in that, include: Acquire multi-source monitoring data including soil profile moisture content, meteorological forecast sequences, and growth stages; Calculate the total basic water and fertilizer supply by combining the growth stage and the soil profile moisture content; When the growth stage indicates the jointing stage and the weather forecast sequence indicates a strong wind trend, the total basic water and fertilizer supply is separated into concentrated fertilizer solution and pushed pure water; the concentrated fertilizer solution is delivered to the soil until it seeps down to the bottom of the current main root system, and then the pushed pure water, whose volume is calculated based on porosity, is delivered. The gravity hydraulic pressure generated by the pushed pure water is used to push the concentrated fertilizer solution to the deep soil layer below the bottom of the current main root system, forcing the main root system to grow deeper; When the meteorological forecast sequence indicates a high temperature trend, pure water from the total basic water and fertilizer supply is used to perform batch drip irrigation on the surface soil. The water infiltration boundary of each batch of drip irrigation is limited to the interior of the surface soil. The canopy heat is absorbed through phase change vaporization, and the conduction of liquid water to the bottom of the current main root system is blocked. When there is no indication of a strong wind trend or a high temperature trend, mixed drip irrigation shall be implemented according to the total amount of basic water and fertilizer supply.

2. The method for dynamic regulation of integrated water and fertilizer management of summer maize based on multi-source data fusion according to claim 1, characterized in that, Acquire multi-source monitoring data including soil profile moisture content, meteorological forecast sequences, and growth stages, including: The shallow, middle and deep moisture contents are obtained by using a group of sensor probes buried at various depths in the planting area, and then the soil profile moisture content is generated by merging them. The wind speed forecast and temperature forecast values ​​for the future time window are obtained through a meteorological data interface and combined to generate the meteorological prediction sequence. By retrieving summer maize sowing time records and accumulated temperature evolution data, and comparing them with the standard summer maize growth accumulated temperature model, the growth stage can be determined.

3. The method for dynamic regulation of integrated water and fertilizer management of summer maize based on multi-source data fusion according to claim 1, characterized in that, Based on the aforementioned growth stage and the soil profile moisture content, calculate the total basic water and fertilizer supply, including: Based on the aforementioned reproductive stage, the corresponding daily average evapotranspiration water consumption is extracted, the current radiation data is obtained, and the theoretical water consumption is calculated in combination with the current radiation data. The effective water storage in the soil profile moisture content is extracted, and the water deficit value is obtained by subtracting the theoretical water consumption from the effective water storage. Based on the nutrient requirements corresponding to the growth stage, fertilizer of corresponding quality is allocated to the water deficit value, and the total basic water and fertilizer supply is obtained.

4. The method for dynamic regulation of integrated water and fertilizer management of summer maize based on multi-source data fusion according to claim 1, characterized in that, Mixed drip irrigation shall be implemented according to the aforementioned basic water and fertilizer supply total, including: The total basic water and fertilizer supply is converted into pipeline control flow parameters; The fertilizer injection pump and clean water valve are opened according to the pipeline control flow parameters, and the actual conductivity of the mixed liquid inside the pipeline is continuously monitored. The actual conductivity is compared with the target nutrient solution conductivity to generate a control deviation.

5. The method for dynamic regulation of integrated water and fertilizer management of summer maize based on multi-source data fusion according to claim 4, characterized in that, After generating the control deviation, the following is also included: The operating frequency of the fertilizer injection pump is dynamically fine-tuned using the aforementioned control deviation. When the actual conductivity falls within the preset conductivity tolerance range, the operating frequency of the fertilizer injection pump is locked until the total amount of basic water and fertilizer supply is delivered.

6. The method for dynamic regulation of integrated water and fertilizer management of summer maize based on multi-source data fusion according to claim 1, characterized in that, Before conveying the pushed pure water whose volume is calculated based on porosity, the process also includes a volume calculation step: Obtain the vertical distance difference between the bottom of the current main root system and the bottom of the deep soil layer; The vertical distance difference corresponds to the physical porosity and current water saturation within the soil medium layer. The available infiltration volume required to contain the liquid is calculated using the vertical distance difference, the physical porosity, and the current water saturation. The available infiltration volume is converted into water volume and used as the volume of pure water to be moved.

7. The method for dynamic regulation of integrated water and fertilizer management of summer maize based on multi-source data fusion according to claim 1, characterized in that, The concentrated fertilizer solution is delivered into the soil until it seeps down to the bottom of the current main root system, followed by the delivery of the pushed pure water, the volume of which is calculated based on porosity, including: Open the fertilizer injection channel to input the concentrated fertilizer solution, and close the fertilizer injection channel when the infiltration front reaches the bottom of the current main root system. The pipeline is kept closed until a preset settling time is reached, allowing the concentrated fertilizer solution to complete lateral capillary diffusion. The pure water is injected into the clear water channel, and the water's own weight fills the shallow pores, creating a downward hydraulic gradient that pushes the concentrated fertilizer solution to settle into the deep soil layer.

8. The method for dynamic regulation of integrated water and fertilizer management of summer maize based on multi-source data fusion according to claim 1, characterized in that, Before using the pure water from the total basic water and fertilizer supply to perform batch drip irrigation on the topsoil, the process also includes: The heat loss required for canopy cooling is calculated based on the difference between the temperature forecast values ​​in the meteorological forecast sequence and the critical heat tolerance temperature of summer maize. Based on the physical constant of latent heat of vaporization, the theoretical total mass of pure water that needs to be evaporated to absorb the lost heat is calculated. Obtain the current pore suction parameters of the surface soil, determine the natural infiltration threshold based on the parameters, divide the total theoretical pure water mass into multiple portions of single pure water injection volume with a mass lower than the natural infiltration threshold, and use these portions as the execution water volume for each batch of drip irrigation.

9. The method for dynamic regulation of integrated water and fertilizer management of summer maize based on multi-source data fusion according to claim 8, characterized in that, The infiltration boundary of water for each batch of drip irrigation is limited to the interior of the surface soil. This is achieved by absorbing canopy heat through phase change vaporization and blocking the conduction of liquid water to the bottom of the current main root system, including: The drip irrigation batches are triggered sequentially according to a preset time interval; After the water from the previous batch of drip irrigation has completely vaporized, the subsequent batch of drip irrigation is triggered. Maintaining the surface soil moisture content below the critical state that would cause downward gravity seepage, thus preventing liquid water from moving downwards.

10. A dynamic regulation system for integrated water and fertilizer management of summer maize based on multi-source data fusion, characterized in that, The method for implementing the dynamic regulation method of integrated water and fertilizer management for summer maize based on multi-source data fusion as described in any one of claims 1 to 9 includes: The data acquisition module is used to acquire multi-source monitoring data, including soil profile moisture content, meteorological forecast sequences, and growth stages. The basic calculation module is used to calculate the total basic water and fertilizer supply by combining the growth stage and the soil profile moisture content; The hydraulic pushing module is used to separate the total basic water and fertilizer supply into concentrated fertilizer solution and pushing pure water when the growth stage indicates the jointing stage and the weather forecast sequence indicates a strong wind trend; to deliver the concentrated fertilizer solution to the soil until it seeps down to the bottom of the current main root system; and then to deliver the pushing pure water with a volume calculated based on porosity; and to use the gravity hydraulic pressure generated by the pushing pure water to push the concentrated fertilizer solution to the deep soil layer below the bottom of the current main root system, forcing the main root system to grow deeper. The phase change vaporization module is used to perform batch drip irrigation on the surface soil with pure water from the total basic water and fertilizer supply when the meteorological forecast sequence indicates a high temperature trend. It limits the water infiltration boundary of each batch of drip irrigation to the interior of the surface soil, absorbs canopy heat through phase change vaporization, and blocks the conduction of liquid water to the bottom of the current main root system. The mixed drip irrigation module is used to perform mixed drip irrigation according to the total amount of basic water and fertilizer supply when there is no indication of a strong wind trend or a high temperature trend.

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