Fertilization and irrigation integrated system capable of cooperatively regulating selenium and cadmium for oilseed rape

Abstract

The invention relates to the technical field of agricultural irrigation, in particular to a fertilization and irrigation integrated system for cooperatively regulating selenium and cadmium of oilseed rape. The system comprises a fertilization irrigation machine, and integrates a soil monitoring unit, a dynamic decision control unit, a water and fertilizer conveying execution unit and a remote monitoring unit. The soil monitoring unit obtains soil key parameters in real time through the soil parameter sensor group, generates comprehensive soil state indexes and transmits the comprehensive soil state indexes to the dynamic decision control unit. The dynamic decision control unit generates a precise irrigation and fertilization strategy according to the soil parameters and transmits the strategy to the water and fertilizer conveying execution unit. The water and fertilizer conveying execution unit is connected with the switching valve through the main irrigation pipeline, and the switching valve is connected with the pulse irrigation branch and the injection branch. The pulse irrigation branch performs pulse irrigation on surface soil, and the injection branch directly injects a selenium fertilizer solution into a root system dense area. By dynamically regulating and controlling the irrigation mode, the utilization rate of the selenium fertilizer is remarkably increased, and efficient technical support is provided for rape planting.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural irrigation, and more specifically, to a fertilization and irrigation integrated system for coordinated regulation of selenium and cadmium in rapeseed. Background Art

[0002] As an important oil crop, rapeseed is widely planted globally. However, during its growth process, it often faces the dual challenges of cadmium (Cd) pollution and selenium (Se) deficiency. In arid regions, this problem is particularly prominent. Due to low soil humidity and high pH values under arid conditions, when selenium fertilizers (such as sodium selenite) are applied, they are prone to combine with calcium and iron ions to form insoluble compounds, resulting in low utilization efficiency of selenium fertilizers (usually <20%), and it is difficult to migrate to the root zone of crops. Existing technologies usually adopt a water-fertilizer separation mode, that is, water is provided through flood irrigation or drip irrigation, and selenium fertilizers are supplemented through surface broadcasting or foliar spraying.

[0003] Although existing technologies attempt to solve the problem of selenium fertilizer supplementation through the water-fertilizer separation mode (such as flood irrigation or foliar spraying), there are still significant problems in the migration efficiency of selenium fertilizers. Specifically, the selenium fertilizers applied by surface broadcasting are difficult to dissolve under arid conditions, and due to low soil humidity and high pH values, selenium fertilizers are prone to combine with cations such as calcium and iron to form insoluble compounds, resulting in selenium fertilizers remaining in the surface soil (0 - 5 cm) and being unable to effectively migrate to the main root distribution layer (15 - 30 cm). This leads to low utilization efficiency of selenium fertilizers (usually <20%), making it difficult to meet the nutritional requirements of crops for selenium, and at the same time exacerbating the problems of selenium fertilizer waste and soil immobilization. Summary of the Invention

[0004] The present invention provides a fertilization and irrigation integrated system for coordinated regulation of selenium and cadmium in rapeseed. It is connected to a switching valve through a main irrigation pipeline, and the switching valve is respectively connected to a pulse irrigation branch and an injection branch. The pulse irrigation branch performs pulse irrigation on the surface soil (0 - 15 cm), and the injection branch directly injects the selenium fertilizer solution into the root dense area (15 - 30 cm). The system automatically switches between the pulse injection composite mode and the root-targeted injection mode according to soil humidity and selenium concentration, realizing the efficient utilization of selenium fertilizers, thereby solving the problem raised in the above background art, that is, the problem of low utilization efficiency of selenium fertilizers in arid regions due to soil immobilization and low migration efficiency.

[0005] To achieve the above object, the system includes a fertilization and irrigation machine, which integrates a soil monitoring unit and a water and fertilizer delivery execution unit. The soil monitoring unit obtains key soil parameters in real time. The key soil parameters include the contents of cadmium and selenium, temperature, humidity, and pH value. It also includes a dynamic decision-making control unit, which generates a first decision, where:

[0006] Generate a first irrigation and fertilization strategy based on temperature and pH value;

[0007] The water and fertilizer delivery execution unit performs temperature compensation, corrects the selenium availability score, and optimizes the irrigation period based on the first irrigation and fertilization strategy to inhibit the adsorption and passivation of selenium fertilizer in the soil at high temperatures and high pH values.

[0008] Generate a precise irrigation and fertilization strategy based on the cadmium and selenium content and humidity.

[0009] The fertilization irrigation machine includes a main irrigation pipeline, the main irrigation pipeline is connected to a switching valve, the switching valve includes a rotary valve and an electromagnetic three-way valve, the rotary valve adjusts the opening and closing of the main passage, the electromagnetic three-way valve distributes the flow of the mixing mode, and the switching valve is respectively connected to a pulse irrigation branch and an injection branch.

[0010] The water and fertilizer delivery execution unit performs pulse irrigation on the surface soil through the pulse irrigation branch and performs pulse injection composite mode and root-targeted injection mode on the root-intensive area through the injection branch based on the precise irrigation and fertilization strategy to migrate the selenium fertilizer to the main root distribution layer.

[0011] In the above technical solution, the selenium fertilizer mainly penetrates from the surface soil to the root area. However, due to the low soil humidity and high pH value, the selenium fertilizer is easily combined with cations such as calcium and iron to form insoluble compounds, resulting in difficulty in migrating the selenium fertilizer to the deep root area (15 - 30 cm), affecting the nutrient absorption and growth of crops. The present invention generates the first irrigation and fertilization strategy based on temperature and pH value to ensure that the basic environmental conditions are suitable for the effective utilization of selenium fertilizer and the passivation of cadmium; subsequently, a precise irrigation and fertilization strategy is generated based on detailed parameters such as cadmium and selenium content and humidity. The dynamic decision control unit (700) uses a multi-objective optimization algorithm to determine the optimal irrigation modes, including pulse irrigation, root-targeted injection, and mixing mode, to balance the selenium fertilizer utilization rate, cadmium passivation effect, and water resource consumption. The main irrigation pipeline is equipped with a switching valve, and a combined design of a rotary valve and an electromagnetic three-way valve is adopted. The rotary valve adjusts the opening and closing of the main passage to ensure the stable flow of the main irrigation pipeline; the electromagnetic three-way valve distributes the flow of the mixing mode in real time according to the instructions of the dynamic decision control unit and distributes it to the pulse branch and the injection branch in a 7:3 ratio to ensure the coordinated operation of the pulse irrigation branch and the injection branch.

[0012] On this basis, the bottom of the pulse irrigation branch (300) is provided with self-cleaning drip heads, and pulse irrigation is performed on the surface soil through the self-cleaning drip heads to quickly increase the surface soil humidity and allow the selenium fertilizer to migrate towards the roots.

[0013] In another technical solution, a micro pump and a retractable injection needle are provided at the bottom of the injection branch (400). The pulse injection composite mode and the root-targeted injection mode are carried out on the root-intensive area through the micro pump and the retractable injection needle. The head of the retractable injection needle is integrated with an atomizing nozzle, which is used to accelerate the diffusion efficiency of selenium fertilizer in the rhizosphere soil.

[0014] In this technical solution, the surface soil humidity is rapidly increased through high-frequency pulse irrigation to promote the migration of selenium fertilizer to the roots. At the same time, through the precise positioning of the retractable injection needle and the diffusion effect of the atomizing nozzle, it is ensured that the selenium fertilizer is directly delivered to the root-intensive area, avoiding the problem of the formation of insoluble compounds by the combination of selenium fertilizer with cations such as calcium and iron in the surface soil.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. Among the three injection methods of dynamic pulse irrigation, pulse injection composite mode, and root-targeted injection used in the present invention, if only dynamic pulse irrigation and root-targeted injection are adopted and the mixed mode is lacking, when the soil humidity and selenium concentration are both insufficient, the system will fall into a dilemma of "water replenishment causing selenium loss" or "delaying water replenishment to preserve selenium"; if there are only pulse irrigation and mixed mode and the targeted injection is missing, the selenium fertilizer in the low-selenium soil cannot bypass the surface oxidation layer and reach the roots directly, and it will still be ineffective due to soil adsorption; if there are only targeted injection and mixed mode and pulse irrigation is abandoned, the accumulation of surface soil salts will hinder the infiltration of water, resulting in the inability to absorb the selenium fertilizer injected deep, and through the effective combination of the three, the problem of the difficulty in coordinating the water management, selenium fertilizer supply, and soil environment in traditional irrigation and fertilization is solved.

[0017] 2. By adopting the combined design of a rotary valve and an electromagnetic three-way valve, which is different from the traditional single valve control or the method of independently setting valves for each branch, the continuity and stability of irrigation are significantly improved. Specifically, the rotary valve is responsible for the opening and closing control of the main passage to ensure the smooth switching of the overall water flow; while the electromagnetic three-way valve precisely adjusts the flow ratio between different branches to achieve dynamic adjustment of surface irrigation (0 - 15 cm) and deep injection (15 - 30 cm). Compared with the prior art, this combined design can more effectively respond to the changes in crop growth requirements, optimize the utilization efficiency of water resources and selenium fertilizer, and avoid waste of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall process structure of the present invention;

[0019] Figure 2 It is a schematic diagram of the process of the soil monitoring unit in the embodiment of the present invention;

[0020] Figure 3 It is a schematic diagram of the process of the water and fertilizer delivery execution unit in the embodiment of the present invention;

[0021] Figure 4 Schematic diagram of the water and fertilizer flow streamline for the embodiment of the present invention;

[0022] Figure 5 Front view schematic diagram of the mechanical support structure for the embodiment of the present invention;

[0023] Figure 6 Schematic diagram of the structure of the soil parameter sensor group for the embodiment of the present invention.

[0024] The meanings of the various reference numerals in the figure are as follows:

[0025] 100, main irrigation pipeline; 200, switching valve; 2001, electromagnetic three-way valve; 2002, rotary valve; 300, pulse irrigation branch; 400, injection branch; 500, drip irrigation tape; 600, soil monitoring unit; 6001, electrochemical sensor; 6002, temperature and humidity sensor; 6003, pH sensor; 6004, stainless steel probe; 6005, support arm; 6006, slide rail; 700, dynamic decision-making control unit; 800, water and fertilizer delivery execution unit; 900, remote monitoring unit. Detailed implementation manners

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] At the same time, some technical terms are explained herein:

[0028] LoRa (Long Range) is a low-power wide area network (LPWAN) communication technology suitable for long-distance and low-power Internet of Things applications. LoRa is famous for its long-distance transmission (up to 10 kilometers) and low-power characteristics, and is suitable for farmland monitoring in remote areas;

[0029] As Figure 6 shown, the surface soil refers to the soil in the area 0 - 5 cm below the upper layer of the soil;

[0030] RS485 is an industrial standard differential serial communication protocol that supports long-distance (≤1200 meters) and multi-device (≤32 nodes) half-duplex data transmission.

[0031] Currently, for the problem that selenium fertilizer cannot effectively migrate to the main root distribution layer, resulting in low utilization rate of selenium fertilizer in rapeseed cultivation in arid areas, the present invention provides a fertilization and irrigation integrated system for synergistic regulation of selenium and cadmium in rapeseed, aiming to improve the migration efficiency and utilization rate of selenium fertilizer through precise water-fertilizer integration technology. Refer to Figure 1 As shown, specifically through the collaborative work of the fertilization and irrigation machine and its integrated soil monitoring unit 600, dynamic decision-making control unit 700, water-fertilizer delivery execution unit 800 and remote monitoring unit 900, the core problem of low selenium fertilizer migration efficiency in arid areas is solved.

[0032] Refer to Figure 2 As shown, the soil monitoring unit 600 is the core of data acquisition of the fertilization and irrigation machine. Through the collaborative work of the soil parameter sensor group (refer to Figure 5 As shown, electrochemical sensor 6001, temperature and humidity sensor 6002, pH sensor 6003), the key soil parameters (including the contents of cadmium and selenium, temperature, humidity and pH value) are obtained in real time. As Figure 6 shown, the electrochemical sensor 6001 adopts a stainless steel probe 6004 and waterproof packaging, and the probe length is adjustable (0 - 30 cm), which can adapt to soil layer detection at different depths, and is mainly used to detect the cadmium (Cd) and selenium (Se) contents in the root distribution layer (15 - 30 cm), with a detection accuracy of ±0.01 mg / kg. The temperature and humidity sensor 6002 is internally equipped with a thermistor and a capacitive humidity probe, and realizes close contact with the soil through a spring telescopic mechanism. Its bottom end is also provided with a stainless steel probe 6004, and the soil humidity (accuracy ±2%) and temperature (accuracy ±0.5 °C) of the 0 - 30 cm layer are monitored in real time through the stainless steel probe 6004. The pH sensor 6003 adopts an integrated probe integrating a glass electrode and a reference electrode, and its surface is covered with an anti-corrosion coating, which is used to measure the pH value of the surface soil, with an accuracy of ±0.2. The wireless transmission node adopts a unitized metal shell, and is internally equipped with a solar power supply panel and a lightning protection circuit, and is responsible for encrypting the sensor data and transmitting it to the control center through LoRa. Refer to Figure 5 As shown, the soil parameter sensor group realizes the precise positioning and dynamic monitoring of the soil parameter sensor group through a modular mechanical support structure. The mechanical support structure includes an adjustable support arm 6005 and a slide rail 6006. The electrochemical sensor 6001, temperature and humidity sensor 6002 and pH sensor 6003 are successively arranged on the slide rail 6006 from outside to inside. The bottom ends of the electrochemical sensor 6001 and the temperature and humidity sensor 6002 are both provided with stainless steel probes 6004. The support arm 6005 is made of carbon fiber material, and the depth of the sensor probe can be adjusted up and down. The sensor can move on the slide rail 6006 to cover different monitoring points.

[0033] During the working process, the electrochemical sensor 6001 detects the cadmium and selenium contents; the temperature and humidity sensor 6002 collects humidity and temperature data; the pH sensor 6003 measures the acidity and alkalinity of the surface soil. The collected raw data is filtered for noise and temperature-compensated by the built-in MCU, and then data fusion is performed to generate comprehensive soil status indicators (such as selenium availability score, cadmium activity index). The calibrated comprehensive soil status indicators are packaged and sent to the dynamic decision control unit 700 through the wireless transmission node, and the transmission interval does not exceed 5 minutes. Finally, the soil monitoring unit 600 outputs the calibrated comprehensive soil status indicators, including soil humidity (stratified data of 0 - 30 cm), cadmium / selenium content (root distribution layer, 15 - 30 cm), pH value, and temperature (surface soil, 0 - 5 cm).

[0034] The dynamic decision control unit 700 generates a precise irrigation and fertilization strategy by receiving the comprehensive soil status indicators transmitted by the soil multi-parameter monitoring unit and combining the preset regulation logic and algorithms. It includes an embedded processor, data storage, a control signal output interface, and a mechanical operation panel. The embedded processor uses a high-performance ARM architecture and has built-in multi-thread processing capabilities. The data storage uses a solid-state drive (SSD) to store historical data and model parameters, supporting fast read / write and data backup. The control signal output interface is connected to the actuators (rotary valves, electromagnetic three-way valves, etc.) through RS485 to ensure the stability and real-time nature of signal transmission. The mechanical operation panel is designed to be waterproof and dustproof, equipped with physical buttons and an LCD display, and supports manual mode switching and parameter adjustment.

[0035] During the working process, the dynamic decision control unit 700 first receives the calibrated data transmitted by the soil multi-parameter monitoring unit, including soil humidity (stratified data of 0 - 30 cm), cadmium / selenium content (root distribution layer, 15 - 30 cm), pH value, and temperature (surface soil, 0 - 5 cm). Subsequently, the embedded processor further processes the data.

[0036] The embedded processor first performs temperature compensation on the cadmium / selenium data collected by the electrochemical sensor 6001. According to the real-time temperature data (accuracy ±0.5°C) stratified at 0 - 30 cm, correction is carried out according to the algorithm of compensating 0.5% of the selenium detection value for every 1°C increase in temperature. At the same time, the surface soil acidity data (0 - 5 cm, accuracy ±0.2) provided by the pH sensor 6003 is used to correct the selenium availability score: when pH > 7.5, the system automatically reduces the selenium availability score by 20% and triggers the high-frequency pulse irrigation mode (7 Hz) to enhance the migration efficiency of selenium in alkaline soil; when pH < 6.0, an optimization plan for acidic soil is initiated, raising the target selenium-cadmium ratio (Se / Cd) from 5 to 8 and offsetting the fixation of selenium in acidic soil by increasing the selenium fertilizer injection amount by 20%. The temperature data is also used to optimize the irrigation period. When the surface temperature exceeds 30°C, the system automatically adjusts the irrigation operation to early morning or evening to avoid water evaporation and selenium fertilizer decomposition caused by high temperature.

[0037] The dynamic decision-making control unit 700 first generates a preliminary first irrigation and fertilization strategy based on the preliminarily evaluated soil temperature and pH value. This stage is mainly to ensure that the basic environmental conditions are suitable for the effective utilization of selenium fertilizer and the passivation of cadmium. Based on these initial conditions, the system can make preliminary adjustments, such as optimizing the irrigation frequency or selecting a suitable irrigation time period, to cope with the impact of different environmental factors on crop growth.

[0038] Subsequently, the dynamic decision-making control unit 700 further runs a multi-objective optimization algorithm, comprehensively considering more parameters, including soil moisture, selenium and cadmium content, etc., to refine the first irrigation and fertilization strategy. This algorithm aims to balance the selenium fertilizer utilization rate, cadmium passivation effect and water resource consumption, and determine the best irrigation mode (pulse irrigation, root-targeted injection and mixed mode), irrigation frequency and water volume, as well as the specific application amounts of selenium fertilizer and passivator. In this way, the system can not only adapt to different soil and crop conditions, but also ensure that every drop of water and every portion of fertilizer are efficiently utilized. Finally, the generated precise irrigation and fertilization strategy is converted into execution instructions through the control signal output interface and transmitted to the water and fertilizer delivery execution unit 800 for implementation.

[0039] The water and fertilizer delivery execution unit 800 is the core execution part of the fertilization irrigation machine, responsible for realizing the efficient delivery and precise regulation of selenium fertilizer and irrigation water according to the precise irrigation and fertilization strategy transmitted by the dynamic decision-making control unit 700. This unit receives the strategy transmitted by the dynamic decision-making control unit 700, including irrigation mode (dynamic pulse irrigation, pulse injection composite mode, root-targeted injection), irrigation frequency and water volume, application amounts of selenium fertilizer and passivator, etc., and performs corresponding operations according to the strategy.

[0040] See Figure 3 、 Figure 4As shown in the figure, the fertilizing irrigation machine of the present invention is connected to a switching valve 200 through a main irrigation pipeline 100, and is respectively connected to a pulse irrigation branch 300 and an injection branch 400 through the switching valve 200 to achieve efficient water and fertilizer transportation and precise regulation. The main irrigation pipeline 100 is made of corrosion-resistant stainless steel with a smooth inner wall design. The switching valve 200 controls the flow direction of water and fertilizer through the combination of a rotary valve 2002 and an electromagnetic three-way valve 2001: the rotary valve 2002 adjusts the opening and closing of the main passage, and the electromagnetic three-way valve 2001 distributes the flow rate of the mixing mode. The electromagnetic three-way valve 2001 opens and closes at a frequency of 5 Hz according to the command to drive the drip irrigation tape 500 to perform surface irrigation of 0 - 15 cm; the injection branch 400 drives a retractable injection needle through a micro pump, and the head of the injection needle is integrated with an atomizing nozzle. The injection depth is controlled by a stepping motor at 0 - 30 cm, and the injection frequency is 2 Hz. The root location sensor 6 is deployed near the injection needle, and the position of the root dense area is real-time feedback through soil resistivity detection.

[0041] In the case of low soil humidity (<40% field water holding capacity), the system starts the dynamic pulse irrigation mode. At this time, the water and fertilizer mixture enters the pulse irrigation branch 300 through the main irrigation pipeline 100, and the electromagnetic three-way valve 2001 controls the water flow with a high-frequency pulse of 5 Hz. The single water volume is 0.1 L, driving the self-cleaning drip head to perform surface irrigation (0 - 15 cm). The high-frequency pulse water flow can quickly penetrate the selenium fertilizer solution into the root area, and at the same time prevent the drip head from being blocked through the reverse flushing function. This mode is suitable for the initial stage of drought, which can quickly increase the surface soil humidity and promote the migration of selenium fertilizer to the roots. In this state, the rotary valve 2002 remains fully open to ensure the smooth flow of water in the main irrigation pipeline 100. At this time, the electromagnetic three-way valve 2001 completely closes the channel of the injection branch 400 and directs all the water and fertilizer flow to the pulse irrigation branch 300. This high-frequency pulse design can not only quickly improve the surface soil moisture, but also effectively prevent the drip head from being blocked.

[0042] When the soil humidity is moderate (40% - 70% of field capacity) and the selenium concentration is low (0.03 - 0.05 mg / kg), the system switches to the pulse injection composite mode. At this time, the water-fertilizer mixture enters the pulse irrigation branch 300 and the injection branch 400 simultaneously through the main irrigation pipeline 100. The pulse irrigation branch 300 delivers 0.3 L of the water-fertilizer mixture per time to the surface layer (0 - 15 cm) at a frequency of 3 Hz to further supplement the selenium fertilizer in the surface layer; the injection branch 400 drives the retractable injection needle through a micro pump and directly injects the selenium fertilizer solution into the root-intensive area (15 - 30 cm) at a frequency of 1 Hz. In this state, the rotary valve 2002 remains fully open, while the electromagnetic three-way valve (2001) intelligently distributes the flow rate in a ratio of 7:3: 70% of the flow rate enters the pulse irrigation branch 300 to deliver 0.3 L of the water-fertilizer mixture per time for surface irrigation at a frequency of 3 Hz; at the same time, 30% of the flow rate enters the injection branch 400. This mode combines surface pulse and deep injection, which not only ensures the continuous penetration of selenium fertilizer in the surface layer but also realizes the precise supplement in the root area, and is suitable for the growth period with high selenium fertilizer requirements.

[0043] When the soil humidity is moderate (40% - 70% of field capacity) and the selenium concentration is extremely low (< 0.03 mg / kg), the system switches to the root-targeted injection mode. In this state, the rotary valve 2002 continues to remain fully open, and the electromagnetic three-way valve 2001 completely closes the pulse irrigation branch 300 and concentrates all the flow rate on the injection branch 400. At this time, the water-fertilizer mixture enters the injection branch 400 in full volume through the main irrigation pipeline 100. The retractable injection needle automatically adjusts the retractable depth (15 - 30 cm) according to the root density data feedback by the soil resistivity sensor and injects 0.5 L of the selenium fertilizer solution per time at a frequency of 2 Hz. The injection needle head is integrated with an atomizing nozzle to further improve the diffusion efficiency of the selenium fertilizer in the rhizosphere soil. This mode focuses on the precise supplement in the root-intensive area and is suitable for scenarios with extremely high selenium fertilizer requirements and limited surface supplement effects.

[0044] In addition, the system dynamically adjusts the injection strategy according to the real-time monitored soil temperature and pH value: when the temperature of the root zone exceeds 28°C, the injection frequency is automatically reduced from the standard 2 Hz to 1 Hz to reduce the high-temperature decomposition of the selenium solution, and at the same time, the single injection volume is increased from 0.5 L to 0.8 L to maintain the total selenium fertilizer supply; under low-temperature conditions (<15°C), the injection frequency is increased to 3 Hz and the single volume is reduced to 0.3 L to enhance the diffusion efficiency of selenium fertilizer in cold soil. For abnormal pH values, when acidic soil (pH < 6.0) is detected, the system increases the injection volume by 20% to overcome the fixation of selenium by the soil; under alkaline conditions (pH > 8.0), the deep injection mode is activated, and the injection depth is adjusted from the conventional 15 - 30 cm to 20 - 35 cm to avoid the high-pH surface soil. These parameter adjustments are all achieved through the PID control system of the micro pump and the precise positioning of the stepper motor to ensure that the optimal selenium-cadmium ratio (Se / Cd ≥ 5) can be maintained under different environmental conditions. The atomizing nozzle integrated with the injection needle automatically changes the atomizing particle size according to the adjusted flow rate, using large-particle atomization of 150 μm in the high-temperature and high-flow mode to reduce drift, and switching to fine mist of 80 μm in the low-temperature and high-frequency mode to enhance the diffusion uniformity.

[0045] At the same time, the system realizes the precise control of the selenium-cadmium ratio (Se / Cd ≥ 5) by dynamically regulating the application rate of selenium fertilizer. When the cadmium activity index ≥ 0.8, the injection branch 400 automatically increases the selenium fertilizer injection volume by 20% (up to 0.6 L / time) to inhibit the absorption of cadmium by increasing the effective concentration of selenium. In the pulse co-injection mode, the system monitors the Se / Cd ratio in real time. If Se / Cd < 5 is detected, the injection frequency in the root-dense area is preferentially increased (from 1 Hz to 2 Hz); in the root-targeted injection mode, the maximum injection volume (0.6 L / time) is directly used to quickly increase the selenium concentration in the root zone. This dynamic regulation mechanism based on the selenium-cadmium ratio ensures the efficient utilization of selenium fertilizer and effectively controls the absorption of cadmium by rapeseed without the need to add additional cadmium passivators.

[0046] In this embodiment, the mechanical structure achieves efficient functional collaboration through modular design: the main irrigation pipeline 100 and the switching valve 200 together constitute the water conveyance center. The pulse irrigation branch 300 and the injection branch 400 are respectively optimized for surface infiltration and deep targeted delivery to ensure that water and nutrients can accurately reach the areas required by crop roots. In particular, the combined design of the rotary valve 2002 and the electromagnetic three-way valve 2001 plays a key role in this system. Compared with the traditional method of using a single valve or setting valves independently for each branch, this combination not only simplifies the complexity of the system, reduces the maintenance cost, but also can control the water flow direction and distribution ratio more flexibly and accurately, improving the utilization efficiency of water resources and fertilizers. In addition, the application of the root positioning sensor further ensures the execution accuracy, making the entire fertilization and irrigation process more intelligent and refined. All mechanical units are integrated into one body through rigid connections and signal lines, forming a compact and efficient fertilization and irrigation machine main body, providing strong support for the growth of rapeseed.

[0047] Finally, the water and fertilizer delivery execution unit 800 executes corresponding irrigation and fertilization operations according to the strategy of the dynamic decision-making control unit 700, and transmits the execution results (irrigation water volume, fertilization amount, mode status) to the remote monitoring unit 900 through the control signal output interface. Through the design of the water and fertilizer delivery execution unit 800, the present invention realizes the efficient utilization and precise delivery of selenium fertilizer, and solves the core problem of low migration efficiency of selenium fertilizer in arid areas.

[0048] The remote monitoring unit 900 is responsible for receiving the execution results (irrigation water volume, fertilization amount, mode status) transmitted by the dynamic decision-making control unit 700, and optimizing the system operation through data analysis and feedback. This unit is integrated into the control box of the fertilization and irrigation machine, and includes a wireless transmission node, data storage, a remote communication module and a mechanical operation panel. The wireless transmission node uses LoRa technology to encrypt and transmit the execution results to the remote monitoring platform; the data storage uses a solid-state drive (SSD) to store historical data and model parameters; the remote communication module supports 4G / 5G networks to ensure the real-time and stability of data transmission; the mechanical operation panel is equipped with physical buttons and an LCD display screen, supporting manual mode switching and parameter adjustment.

[0049] During the working process, the remote monitoring unit 900 first receives the execution results transmitted by the dynamic decision-making control unit 700, including data such as irrigation water volume, fertilization amount, and mode status. Subsequently, the built-in MCU analyzes the data and calculates the system operation efficiency and selenium fertilizer utilization rate. The formulas are as follows:

[0050]

[0051] In the formula, η represents the system operation efficiency;

[0052] Q实际 represents the actual irrigation water volume;

[0053] Q 理论 represents the theoretical water absorption.

[0054]

[0055] In the formula, U Se represents the utilization rate of selenium fertilizer;

[0056] S 吸收 represents the amount of selenium fertilizer absorbed by the crop;

[0057] S 施用量 represents the amount of selenium fertilizer applied to the system.

[0058] Based on the analysis results, the remote monitoring unit 900 generates optimization suggestions (such as adjusting the irrigation frequency and fertilization amount), and feeds them back to the fertilization irrigation machine through the wireless transmission node. At the same time, the mechanical operation panel displays the current system status and optimization suggestions, supporting manual intervention and adjustment. Finally, through real-time data collection, analysis, and feedback, the remote monitoring unit 900 realizes the intelligent management of the fertilization irrigation machine, significantly improving the utilization rate of selenium fertilizer and the system operation efficiency.

[0059] In summary, through the mechanical design of the multi-mode linkage switching valve and the dynamic regulation of the system process, the present invention realizes the precise switching and flow distribution of three modes: dynamic pulse irrigation, pulse injection composite mode, and root-targeted injection, solves the problem of low utilization rate of selenium fertilizer in arid areas due to soil immobilization and low migration efficiency, and provides efficient and precise technical support for rapeseed planting.

[0060] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention, and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A rapeseed selenium and cadmium coordinated fertilization and irrigation integrated system, comprising a fertilization and irrigation machine, wherein the fertilization and irrigation machine integrates a soil monitoring unit (600) and a water and fertilizer delivery execution unit (800), wherein the soil monitoring unit (600) acquires key soil parameters in real time, wherein the key soil parameters include cadmium and selenium content, temperature, humidity and pH value, and wherein: It also includes a dynamic decision control unit (700), which generates a first decision, wherein: Generate the first fertigation strategy based on temperature and pH; Temperature compensation, revised selenium effectiveness score and optimized irrigation period were performed based on the first fertigation strategy to inhibit the adsorption and passivation of selenium fertilizer in the soil at high temperature and high pH value; Generate precision fertigation strategies based on cadmium and selenium levels and moisture; The fertilizer irrigation machine comprises a main irrigation pipeline (100), wherein the main irrigation pipeline (100) is respectively connected to a pulse irrigation branch (300) and an injection branch (400); The water and fertilizer transport execution unit (800) performs pulse irrigation on the surface soil through the pulse irrigation branch (300) based on the precision irrigation and fertilization strategy, and performs a pulse injection composite mode and a root system targeted injection mode on the root system dense area through the injection branch (400), so as to migrate the selenium fertilizer to the main root distribution layer.

2. The rapeseed selenium and cadmium coordinated regulation integrated fertilization and irrigation system according to claim 1, characterized in that: The fertilizer irrigation machine is provided with a slide rail (6006), on which an electrochemical sensor (6001), a temperature and humidity sensor (6002) and a pH sensor (6003) are arranged in sequence from the outside to the inside, so as to obtain key soil parameters in real time and generate a comprehensive soil status index.

3. The integrated fertilization and irrigation system for rapeseed with coordinated regulation of selenium and cadmium according to claim 1, characterized in that: The soil monitoring unit (600) transmits the comprehensive soil state index to the dynamic decision control unit (700), prompting it to generate a precise irrigation and fertilization strategy.

4. The integrated fertilization and irrigation system for rapeseed selenium and cadmium coordinated regulation according to claim 1, characterized in that: The dynamic decision control unit (700) is provided with an embedded processor, which receives temperature data and performs temperature compensation thereon, and receives surface soil pH data to correct the selenium effectiveness score.

5. The rapeseed selenium and cadmium coordinated regulation integrated fertilization and irrigation system according to claim 1, characterized in that: The dynamic decision control unit (700) uses a multi-objective optimization algorithm to balance the utilization rate of selenium fertilizer, the cadmium passivation effect and the water resource consumption, and transmits the precise irrigation and fertilization strategy to the water and fertilizer delivery execution unit (800).

6. The rapeseed selenium and cadmium coordinated regulation integrated fertilization and irrigation system according to claim 2, characterized in that: The bottom ends of the electrochemical sensor (6001) and the temperature and humidity sensor (6002) are both provided with stainless steel probes (6004) for detecting the content of cadmium and selenium, temperature and humidity data in soil at different depths.

7. The rapeseed selenium and cadmium coordinated regulation integrated fertilization and irrigation system according to claim 1, characterized in that: A self-cleaning dripper is provided at the bottom of the pulse irrigation branch (300), and pulse irrigation is performed on the surface soil through the self-cleaning dripper, so as to quickly increase the moisture of the surface soil and allow the selenium fertilizer to migrate to the root system.

8. The rapeseed selenium and cadmium coordinated regulation integrated fertilization and irrigation system according to claim 1, characterized in that: A micro pump and a retractable injection needle are provided at the bottom of the injection branch (400), and a pulse injection composite mode and a root system targeted injection mode are performed on the root-dense area through the micro pump and the retractable injection needle. The retractable injection needle head is integrated with an atomizing nozzle to accelerate the diffusion efficiency of the selenium fertilizer in the rhizosphere soil.

9. The rapeseed selenium and cadmium coordinated regulation integrated fertilization and irrigation system according to claim 1, characterized in that: The main irrigation pipeline (100) is connected to a switching valve (200), and the switching valve (200) comprises a rotary valve (2002) and an electromagnetic three-way valve (2001). The rotary valve (2002) regulates the opening and closing of the main passage, and the electromagnetic three-way valve (2001) distributes the mixed mode flow.

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