A canopy light-nitrogen coupling high-yield regulation method and system for hybrid rice in low-yield fields

Abstract

The present application relates to the field of wisdom agricultural technology, disclose a kind of middle-low yield field hybrid rice canopy light nitrogen coupling high yield regulation method and system, the method includes: in tillering flourishing period to heading stage, obtain the real-time light transmittance of hybrid rice canopy;Based on the hysteresis compensation relationship of real-time light transmittance and leaf nitrogen accumulation quantity, construct nitrogen demand model, output target nitrogen application amount;According to target nitrogen application amount, generate nitrogen application timing instruction, the instruction includes fertilization time point and duration, and adjacent fertilization time interval is dynamically adjusted by light transmittance change rate;Nitrogen application timing instruction is executed and synchronously monitors leaf nitrogen accumulation quantity;Based on the dynamic deviation of leaf nitrogen accumulation quantity and preset nitrogen accumulation quantity threshold, the hysteresis compensation relationship of nitrogen demand model is feedback corrected before the next growth stage starts.The present application realizes the efficient coupling of canopy light resource dynamics and nitrogen precise supply, effectively improves the light nitrogen resource utilization efficiency of middle-low yield field hybrid rice.

Description

Technical Field

[0001] This invention relates to the field of smart agriculture technology, and in particular to a method and system for high-yield regulation of canopy light and nitrogen coupling in hybrid rice in low- and medium-yield fields. Background Technology

[0002] In the field of smart agriculture, rice production in low- and medium-yield fields often faces the problem of low efficiency in utilizing light energy resources. Due to insufficient soil fertility or the presence of obstacles, hybrid rice in these fields is prone to developing an unreasonable canopy structure and uneven leaf distribution during growth, resulting in uneven light distribution within the canopy and low efficiency in capturing and utilizing photosynthetically active radiation.

[0003] Current technologies for regulating the canopy light environment in hybrid rice primarily focus on static methods such as planting density and plant architecture improvement, lacking real-time monitoring and response to dynamic changes in canopy light distribution during key growth stages. Furthermore, nitrogen, a crucial nutrient element affecting rice photosynthetic capacity and canopy structure, is often judged based on experience or static models, failing to fully consider the dynamic impact of real-time changes in the canopy light environment on nitrogen absorption and utilization efficiency, resulting in insufficient spatiotemporal synergy between light and nitrogen resources. This lack of a light-nitrogen coupling mechanism makes it difficult for low- and medium-yield hybrid rice fields to achieve efficient synergistic utilization of light energy and nitrogen nutrients, limiting the realization of yield potential. Summary of the Invention

[0004] This invention provides a method and system for high-yield regulation of light and nitrogen coupling in the canopy of hybrid rice in low- and medium-yield fields. Its main purpose is to solve how to improve the dynamic coupling efficiency of light energy resources and nitrogen nutrients in the canopy of hybrid rice in low- and medium-yield fields during the critical growth period.

[0005] To achieve the above objectives, this invention provides a method for high-yield regulation of canopy light-nitrogen coupling in low- and medium-yield hybrid rice fields, comprising:

[0006] S1. Obtain the real-time light transmittance of the hybrid rice canopy during the critical growth period from the tillering stage to the heading stage;

[0007] S2. Based on the lag compensation relationship between the real-time light transmittance and the nitrogen accumulation in the leaves, a nitrogen demand model is constructed and the target nitrogen application rate is output;

[0008] S3. Generate a nitrogen application timing instruction based on the target nitrogen application amount. The nitrogen application timing instruction includes the fertilization time point and duration, and the time interval between adjacent fertilizations is dynamically adjusted by the transmittance change rate.

[0009] S4. Execute the nitrogen application timing command and simultaneously monitor the nitrogen accumulation in the leaves of hybrid rice;

[0010] S5. Based on the dynamic deviation between the nitrogen accumulation in the leaves and the preset nitrogen accumulation threshold, the lag compensation relationship of the nitrogen demand model is corrected before the start of the next growth stage.

[0011] Optionally, obtaining the real-time transmittance of the hybrid rice canopy includes:

[0012] An array of light intensity sensors was deployed above the canopy of hybrid rice to collect the intensity of incident solar radiation.

[0013] A transmission light sensor array was deployed symmetrically below the canopy of hybrid rice to collect the intensity of transmitted light penetrating the canopy.

[0014] Calculate the instantaneous transmittance ratio based on the incident light intensity and the transmitted light intensity;

[0015] The instantaneous transmittance ratio is subjected to time-series filtering to obtain the real-time transmittance of the hybrid rice canopy.

[0016] Optionally, the hysteresis compensation relationship based on the real-time transmittance and leaf nitrogen accumulation includes:

[0017] Obtain historical light transmittance and corresponding measured values ​​of nitrogen accumulation in leaves during historical growth periods;

[0018] The historical light transmittance is shifted backward by a preset number of days to align with the measured value of nitrogen accumulation in the leaves.

[0019] Calculate the correlation coefficient between the historical light transmittance after translation and the nitrogen accumulation of the leaf, and iteratively adjust the number of translation days until the correlation coefficient reaches its maximum value;

[0020] The number of days of translation corresponding to the maximum correlation coefficient is used as the lag compensation parameter.

[0021] Optionally, constructing the nitrogen demand model and outputting the target nitrogen application rate includes:

[0022] The real-time transmittance is shifted according to the hysteresis compensation parameter to obtain the compensated transmittance of the hybrid rice canopy.

[0023] Establish a linear regression model between the compensated transmittance and the target nitrogen accumulation;

[0024] N target =k·T comp +N soil +N residual -N loss

[0025] Among them, T comp It is the compensation transmittance, k is the photo-nitrogen conversion efficiency factor, and N is the nitrogen conversion efficiency factor. target It is the target nitrogen accumulation, N soilIt is the soil available nitrogen content measured before sowing, N residual It is residual nitrogen that was not utilized in the early stages, N loss This is the amount of ammonia lost through volatilization;

[0026] Input the current light transmittance into the linear regression model to output the target nitrogen application rate.

[0027] Optionally, generating nitrogen application timing instructions based on the target nitrogen application rate includes:

[0028] The target nitrogen application rate is broken down into the total amount of several nitrogen application operations;

[0029] Calculate the absolute value of the rate of change of transmittance at adjacent time points;

[0030] When the absolute value of the rate of change of light transmittance increases, the time interval between adjacent fertilization applications should be shortened.

[0031] When the absolute value of the rate of change of light transmittance decreases, the time interval between adjacent fertilization applications is extended.

[0032] A set of fertilization time points for hybrid rice is generated based on dynamically adjusted time intervals, and an equal amount of nitrogen application is allocated to each fertilization time point in the set.

[0033] Optionally, the synchronous monitoring of nitrogen accumulation in hybrid rice leaves includes:

[0034] After each nitrogen application, functional leaf samples were collected from the middle of the hybrid rice canopy.

[0035] The functional leaf sample was decolorized and dried to obtain dry matter;

[0036] The nitrogen content of the dry matter was determined by the micro Kjeldahl method, and the nitrogen accumulation per unit area of ​​the leaf was calculated in combination with the sample leaf area.

[0037] Optionally, the monitoring and verification of nitrogen accumulation in the leaves includes:

[0038] When the coefficient of variation of continuously monitored leaf nitrogen accumulation exceeds a preset variation threshold, a resampling mechanism is triggered.

[0039] Backup leaf samples were recollected at the same location in the hybrid rice canopy layer.

[0040] If the difference between the measured value of the backup leaf sample and the original sample exceeds the tolerance range, laboratory arbitration testing is activated, and the leaf nitrogen accumulation record is updated with the arbitration test result.

[0041] Optionally, the steps for determining the duration of the nitrogen application timing command are as follows:

[0042] Get the current soil infiltration rate category:

[0043] When the soil is clayey, extend the duration of nitrogen application.

[0044] When the soil is sandy, shorten the duration of nitrogen application.

[0045] Optionally, the step of providing feedback to correct the lag compensation relationship of the nitrogen demand model before the start of the next reproductive stage includes:

[0046] Calculate the dynamic deviation between the nitrogen accumulation in the leaves and the preset nitrogen accumulation threshold;

[0047] When the dynamic deviation remains positive, decrease the daily value of the hysteresis compensation parameter;

[0048] When the dynamic deviation remains negative, increase the day value of the hysteresis compensation parameter;

[0049] The corrected lag compensation parameters are then input into the nitrogen demand model for the next reproductive stage.

[0050] A report on the correction of the lag compensation relationship is generated at the end of the heading period.

[0051] To address the aforementioned problems, this invention also provides a high-yield regulation system for canopy light-nitrogen coupling in low- and medium-yield hybrid rice fields, the system comprising:

[0052] The real-time transmittance acquisition module is used to acquire the real-time transmittance of the hybrid rice canopy during the critical growth period from the tillering stage to the heading stage.

[0053] The nitrogen demand model construction module is used to construct a nitrogen demand model and output the target nitrogen application rate based on the lag compensation relationship between the real-time light transmittance and the nitrogen accumulation in the leaves.

[0054] The nitrogen application timing instruction generation module is used to generate nitrogen application timing instructions based on the target nitrogen application amount. The nitrogen application timing instructions include the fertilization time point and duration, and the time interval between adjacent fertilizations is dynamically adjusted by the transmittance change rate.

[0055] The leaf nitrogen accumulation monitoring module is used to execute the nitrogen application timing command and simultaneously monitor the leaf nitrogen accumulation of hybrid rice.

[0056] The lag compensation relationship correction module is used to correct the lag compensation relationship of the nitrogen demand model before the start of the next growth stage based on the dynamic deviation between the nitrogen accumulation of the leaves and the preset nitrogen accumulation threshold.

[0057] The method and system for high-yield regulation of hybrid rice canopy light-nitrogen coupling provided by this invention have the following significant technical effects: First, by acquiring canopy transmittance in real time during key growth periods and establishing a lag compensation relationship between it and leaf nitrogen accumulation, a dynamic nitrogen demand model is constructed. This model can accurately quantify the dynamic impact of the current canopy light environment on future nitrogen demand, significantly improving the accuracy and timeliness of nitrogen demand prediction and overcoming the lag of traditional experience-based judgments or static models. Second, by generating nitrogen application timing instructions based on the target nitrogen application rate and dynamically adjusting the fertilization interval according to the rate of change in transmittance, the timing and rhythm of nitrogen supply can sensitively respond to changes in canopy structure and light distribution, achieving real-time matching between light resource changes and nitrogen supply, effectively reducing the time misalignment between nitrogen supply and rice physiological needs. Finally, by synchronously monitoring leaf nitrogen accumulation and correcting the lag compensation relationship based on its dynamic deviation from a preset threshold, a closed-loop regulation mechanism is formed, enhancing the model's adaptability and robustness to environmental changes in different fields and different growth stages. This invention effectively improves the synergistic utilization efficiency of light energy resources and nitrogen nutrients in the canopy of hybrid rice in low- and medium-yield fields, providing technical support for high and stable yields. Attached Figure Description

[0058] Figure 1 This is a flowchart illustrating a method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields according to an embodiment of the present invention.

[0059] Figure 2 This is a functional block diagram of a high-yield regulation system for canopy light-nitrogen coupling in low- and medium-yield hybrid rice fields provided in an embodiment of the present invention;

[0060] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0061] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0062] This application provides a method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields. The executing entity of this method includes, but is not limited to, at least one of the following electronic devices that can be configured to execute the method provided in this application: a server, a terminal, etc. In other words, the method for high-yield regulation of hybrid rice canopy light-nitrogen coupling can be executed by software or hardware installed on a terminal device or a server device. The server includes, but is not limited to, a single server, a server cluster, a cloud server, or a cloud server cluster. The server can be an independent server or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content delivery networks (CDNs), and big data and artificial intelligence platforms.

[0063] Reference Figure 1 The diagram shown is a flowchart illustrating a method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields according to an embodiment of the present invention. In this embodiment, the method for high-yield regulation of hybrid rice canopy light-nitrogen coupling includes:

[0064] S1. During the critical growth period from the tillering stage to the heading stage, obtain the real-time light transmittance of the hybrid rice canopy.

[0065] In this embodiment of the invention, obtaining the real-time light transmittance of the hybrid rice canopy includes:

[0066] An array of light intensity sensors was deployed above the canopy of hybrid rice to collect the intensity of incident solar radiation.

[0067] A transmission light sensor array was deployed symmetrically below the canopy of hybrid rice to collect the intensity of transmitted light penetrating the canopy.

[0068] Calculate the instantaneous transmittance ratio based on the incident light intensity and the transmitted light intensity;

[0069] The instantaneous transmittance ratio is subjected to time-series filtering to obtain the real-time transmittance of the hybrid rice canopy.

[0070] In detail, the tillering peak period is the time when the number of tillers in rice reaches its peak during the growth process. During this stage, the rice plants grow vigorously and have a greater demand for nutrients and light. The heading period refers to the period from the beginning of panicle differentiation to heading and flowering. It is a critical stage for rice yield formation, and its growth status directly affects the final yield.

[0071] In detail, the hybrid rice canopy refers to the layered structure formed by the leaves, stems, and other organs of the above-ground part of the hybrid rice plant in the vertical direction, which plays an important role in intercepting and transmitting solar radiation; real-time transmittance refers to the proportion of solar radiation that passes through the hybrid rice canopy at a specific point in time, which is used to reflect the canopy's ability to transmit light energy and is an important basis for subsequent nitrogen regulation.

[0072] In detail, a light intensity sensor array is a device composed of multiple light intensity sensors arranged according to certain rules, used to collect light intensity data of solar radiation.

[0073] In detail, incident light intensity refers to the intensity of solar radiation reaching above the canopy of hybrid rice, and its value directly affects the calculation of the canopy transmittance; transmitted light intensity refers to the intensity of solar radiation reaching below the canopy after passing through it, and the transmittance can be calculated by comparing it with the incident light intensity.

[0074] In detail, the instantaneous transmittance ratio is the ratio of the intensity of transmitted light below the canopy to the intensity of incident light above the canopy at the same time point, and is used to preliminarily measure the light transmittance of the canopy; time series filtering is a method of processing instantaneous transmittance ratio data collected in chronological order, and by eliminating noise and fluctuations in the data, it obtains data that better reflects the true transmittance trend.

[0075] Specifically, a light intensity sensor array, comprising multiple light intensity sensors (e.g., photosynthetically active radiation sensors), is deployed at a suitable location above the hybrid rice canopy to ensure accurate acquisition of the incident light intensity of solar radiation. Simultaneously, a transmission light sensor array, using the same type of sensor, is deployed symmetrically below the canopy to ensure the consistency and comparability of the acquired data.

[0076] In detail, data is collected in real time through a sensor array, with a reasonable acquisition frequency set, such as collecting incident light intensity and transmitted light intensity data every 10 minutes. During the acquisition process, it is ensured that the sensors are operating normally to avoid inaccurate data due to equipment failure.

[0077] In detail, for each collected incident light intensity and transmitted light intensity data, the instantaneous transmittance ratio is calculated using a formula, that is, the instantaneous transmittance ratio equals the transmitted light intensity divided by the incident light intensity. For example, if the incident light intensity collected at a certain moment is I... in The intensity of transmitted light is I out The instantaneous transmittance ratio is I. out / I in .

[0078] In detail, the calculated instantaneous transmittance ratio is subjected to time-series filtering. A moving average filtering algorithm is used, and an appropriate filtering window size is selected, such as 12 time points (equivalent to 2 hours of data). This algorithm smooths the data, eliminating noise interference caused by factors such as short-term light changes, thereby obtaining real-time transmittance that can truly reflect the trend of transmittance changes in the hybrid rice canopy.

[0079] In summary, this step, by symmetrically deploying sensor arrays above and below the canopy and performing precise data acquisition and processing, can accurately obtain the real-time transmittance of the hybrid rice canopy. This provides a reliable data foundation for the subsequent construction of a nitrogen demand model based on the light-nitrogen coupling relationship and nitrogen application regulation. It solves the problem of low nitrogen regulation efficiency caused by inaccurate transmittance measurement in the background technology, making the monitoring of the light environment during rice growth more accurate.

[0080] S2. Based on the lag compensation relationship between the real-time light transmittance and the nitrogen accumulation in the leaves, a nitrogen demand model is constructed and the target nitrogen application rate is output.

[0081] In this embodiment of the invention, the hysteresis compensation relationship based on the real-time transmittance and leaf nitrogen accumulation includes:

[0082] Obtain historical light transmittance and corresponding measured values ​​of nitrogen accumulation in leaves during historical growth periods;

[0083] The historical light transmittance is shifted backward by a preset number of days to align with the measured value of nitrogen accumulation in the leaves.

[0084] Calculate the correlation coefficient between the historical light transmittance after translation and the nitrogen accumulation of the leaf, and iteratively adjust the number of translation days until the correlation coefficient reaches its maximum value;

[0085] The number of days of translation corresponding to the maximum correlation coefficient is used as the lag compensation parameter.

[0086] Specifically, the construction of the nitrogen demand model and the output of the target nitrogen application rate include:

[0087] The real-time transmittance is shifted according to the hysteresis compensation parameter to obtain the compensated transmittance of the hybrid rice canopy.

[0088] Establish a linear regression model between the compensated transmittance and the target nitrogen accumulation;

[0089] N target =k·T comp +N soil +N residual -N loss

[0090] Among them, T comp It is the compensation transmittance, k is the photo-nitrogen conversion efficiency factor, and N is the nitrogen conversion efficiency factor.target It is the target nitrogen accumulation, N soil It is the soil available nitrogen content measured before sowing, N residual It is residual nitrogen that was not utilized in the early stages, N loss This is the amount of ammonia lost through volatilization;

[0091] Input the current light transmittance into the linear regression model to output the target nitrogen application rate.

[0092] In detail, the historical growth period refers to the complete growth stage of hybrid rice from the peak tillering stage to the heading stage in the past growth process, which includes key data on the rice's light and nitrogen requirements; the historical light transmittance is the canopy light transmittance data of hybrid rice obtained by collecting data through a light intensity sensor array during the historical growth period and after time series filtering, reflecting the canopy light transmittance at the same growth stage in the past.

[0093] In detail, the measured value of nitrogen accumulation in leaves is the actual measured value of nitrogen content per unit area of ​​leaves obtained by sampling, decolorizing, drying and determining nitrogen content by Kjeldahl method of hybrid rice leaves, which reflects the actual accumulation of nitrogen during rice growth.

[0094] In detail, the preset number of days is the initial time interval for backward shifting when processing historical transmittance data, which serves as the initial adjustment value for finding the optimal hysteresis compensation parameter; the correlation coefficient is a statistical indicator used to measure the degree of linear correlation between the shifted historical transmittance and the measured value of leaf nitrogen accumulation. Its value ranges from -1 to 1, and the larger the absolute value, the stronger the correlation.

[0095] In detail, the lag compensation parameter is the number of translation days that corresponds to the maximum value of the correlation coefficient by iteratively adjusting the translation days. It is used to correct the physiological response lag time between real-time light transmittance and leaf nitrogen accumulation.

[0096] In detail, the compensated transmittance is the transmittance value obtained by time-shifting the real-time transmittance based on the hysteresis compensation parameter, thus eliminating the time difference effect caused by the lag in plant physiological response.

[0097] In detail, the linear regression model is a mathematical model based on the linear relationship between compensated transmittance and target nitrogen accumulation, used to predict the amount of nitrogen accumulation required for hybrid rice growth.

[0098] In detail, the photo-nitrogen conversion efficiency factor is a parameter in the linear regression model that represents the degree of influence of the compensation transmittance on the target nitrogen accumulation. It reflects the change in the target nitrogen accumulation corresponding to a unit change in compensation transmittance and is determined through regression analysis of historical data.

[0099] In detail, the target nitrogen accumulation is the target value of nitrogen accumulation per unit area of ​​leaves required for hybrid rice to achieve high yield at the current growth stage, calculated by a linear regression model, and is expressed in grams per square meter.

[0100] In detail, the available nitrogen content in soil is the amount of nitrogen in the soil that can be directly absorbed and utilized by plants, as determined by potassium chloride extraction-indophenol blue colorimetric method before sowing, and the unit is grams per square meter.

[0101] In detail, the unused residual nitrogen in the previous stage is the nitrogen content in the soil that was not absorbed and utilized by rice in the previous fertilization stage, and is measured in grams per square meter. It is determined through fertilization records and soil nitrogen balance calculations.

[0102] In detail, ammonia volatilization loss is the amount of nitrogen lost due to ammonia volatilization after nitrogen fertilizer is applied to the soil. The unit is grams per square meter, and it is estimated based on parameters such as soil pH, temperature, and moisture content.

[0103] Furthermore, historical light transmittance data of the same hybrid rice variety from the tillering stage to the heading stage over the past 3-5 years were extracted from the database. This data was collected by a light intensity sensor array at a frequency of 10 minutes / time, and the daily average light transmittance was obtained after 12-point moving average filtering.

[0104] Furthermore, the measured values ​​of nitrogen accumulation in leaves were obtained simultaneously each week during the corresponding growth period: Functional leaves from 10 rice plants in the middle of the canopy were selected each time, decolorized with 95% ethanol, dried at 75℃ to constant weight, and the nitrogen content was determined using the micro-Kjeldahl method. The accumulation per unit area (g / m²) was calculated based on the leaf area. 2 ).

[0105] Furthermore, the initial preset number of days is set to 1 day, and the historical transmittance data is shifted forward by this number of days to align the transmittance time point with the sampling time point of the measured leaf nitrogen accumulation value. For example, if a certain nitrogen accumulation value is collected on the 20th day of the growth period, then the transmittance of the 19th day is shifted to the 20th day.

[0106] Furthermore, using the Pearson correlation coefficient algorithm, the correlation coefficient between the historical transmittance after translation and the measured value of nitrogen accumulation in the leaves was calculated based on the translated transmittance and nitrogen accumulation.

[0107] Furthermore, starting from the preset number of days 1, the process is repeated by incrementing by 1 day each time (up to a maximum of 10 days), recording the correlation coefficient corresponding to each number of days. The iteration stops when the correlation coefficient reaches its maximum value and subsequent days no longer show a significant increase (e.g., an increase of <0.05).

[0108] Furthermore, the number of days of shift corresponding to the maximum correlation coefficient is used as the lag compensation parameter. For example, when the correlation coefficient reaches 0.8 after a 5-day shift (significant correlation threshold ≥ 0.7), the lag compensation parameter is 5 days, which reflects the lag time of the effect of transmittance changes on nitrogen accumulation.

[0109] In detail, according to the lag compensation parameter d opt The compensated transmittance T is obtained by time-shifting the current real-time transmittance T(t). comp =T(td) opt For example, the current transmittance is 60%, d opt =5 days, then compensate for light transmittance T comp The light transmittance was 58% five days ago, eliminating the effect of delayed physiological response.

[0110] Furthermore, data on compensated light transmittance and corresponding target nitrogen accumulation during historical growth periods were collected (considering available nitrogen, residual nitrogen, and ammonia volatilization losses in the soil).

[0111] Furthermore, the least squares method is used to fit the regression coefficient k: calculated from historical data. in, This is the mean. For example, historical data fitting yields k = 0.2 g / m. 2 / %, indicates that the unit transmittance corresponds to 0.2g / m². 2 Nitrogen demand.

[0112] Furthermore, the available nitrogen content in the soil was measured before sowing by sampling (e.g., potassium chloride extraction-indophenol blue colorimetric method), the residual nitrogen that was not utilized in the early stage was estimated based on the previous fertilization records and the amount absorbed by rice, and the ammonia volatilization loss was calculated by an ammonia volatilization model (e.g., an empirical formula based on temperature and pH).

[0113] Furthermore, the current compensated transmittance is substituted into the linear regression model to calculate the target nitrogen accumulation. For example, if the compensated transmittance is 58% and the available nitrogen content in the soil measured before sowing is 15 g / m², then... 2 The amount of residual nitrogen that was not utilized in the early stage was 3 g / m³. 2 The ammonia volatilization loss is 2g / m³. 2 The target nitrogen accumulation is 27.6 g / m³. 2 .

[0114] Furthermore, the target nitrogen application rate needs to be further reduced by the existing available nitrogen in the soil (the content of available nitrogen in the soil measured before sowing, the residual nitrogen that was not used in the previous period, and the amount of nitrogen lost through ammonia volatilization) to obtain the actual amount of nitrogen to be applied, which will serve as the basis for generating the subsequent nitrogen application schedule.

[0115] In summary, this step dynamically establishes the lag compensation relationship between real-time light transmittance and leaf nitrogen accumulation, and constructs a nitrogen demand model. Traditional methods do not consider the time difference between light transmittance and nitrogen accumulation, which can easily lead to a mismatch between nitrogen application and actual demand. This step, however, uses historical data to iteratively optimize and determine the lag compensation parameters, enabling the model to accurately reflect the impact of current light transmittance on future nitrogen demand. Simultaneously, the nitrogen demand model comprehensively considers soil background nitrogen, residual nitrogen, and volatilization losses, avoiding nitrogen waste or deficiency caused by indiscriminate fertilization, improving nitrogen fertilizer utilization efficiency, and providing a precise nitrogen demand prediction method for high-yield regulation of hybrid rice in low- and medium-yield fields, effectively enhancing the efficiency of light-nitrogen coupled regulation.

[0116] S3. Generate a nitrogen application timing instruction based on the target nitrogen application amount. The nitrogen application timing instruction includes the fertilization time point and duration, and the time interval between adjacent fertilizations is dynamically adjusted by the transmittance change rate.

[0117] In this embodiment of the invention, generating nitrogen application timing instructions based on the target nitrogen application amount includes:

[0118] The target nitrogen application rate is broken down into the total amount of several nitrogen application operations;

[0119] Calculate the absolute value of the rate of change of transmittance at adjacent time points;

[0120] When the absolute value of the rate of change of light transmittance increases, the time interval between adjacent fertilization applications should be shortened.

[0121] When the absolute value of the rate of change of light transmittance decreases, the time interval between adjacent fertilization applications is extended.

[0122] A set of fertilization time points for hybrid rice is generated based on dynamically adjusted time intervals, and an equal amount of nitrogen application is allocated to each fertilization time point in the set.

[0123] In detail, the target nitrogen application rate is calculated using a nitrogen demand model. It represents the total amount of nitrogen required to achieve high yields in hybrid rice at its current growth stage, taking into account factors such as light transmittance and soil nitrogen content. The nitrogen application timing instruction is a specific fertilization schedule generated based on the target nitrogen application rate. It includes specific fertilization time points, the duration of each fertilization, and the amount of fertilizer applied each time, and is used to guide actual fertilization operations.

[0124] In detail, the fertilization time point refers to the specific moment during the growth process of hybrid rice to carry out fertilization operations, with the time unit as the day and the precision down to the specific date; the duration is the length of time from the start to the end of each fertilization operation, with the unit as the hour, and its setting is related to factors such as soil texture.

[0125] In detail, the time interval between adjacent fertilization operations refers to the time difference between two consecutive fertilization operations, in days. This interval is dynamically adjusted according to the rate of change of light transmittance. The rate of change of light transmittance is the absolute value of the difference in light transmittance between two adjacent time points. It is used to measure the rate of change of light transmittance of the hybrid rice canopy and reflects the dynamic changes in the canopy structure.

[0126] In detail, the total amount of nitrogen applied is the amount of nitrogen required for each fertilization operation after the target amount of nitrogen is broken down. The total amount of nitrogen applied in each operation is usually equal. The set of fertilization time points is a sequence of multiple dynamically adjusted fertilization time points, which constitutes a complete fertilization time arrangement plan.

[0127] Furthermore, based on the expected number of growth days and nitrogen absorption patterns of hybrid rice from the tillering peak to the heading stage, the target nitrogen application rate is broken down into several nitrogen application operations. For example, if the target nitrogen application rate is 28 grams per square meter and the growth cycle is approximately 40 days, it can be broken down into 6-8 nitrogen applications, with each application rate being approximately 3.5-4.7 grams per square meter. The target nitrogen application rate is evenly distributed among the nitrogen application operations to ensure that the amount of nitrogen applied each time is equal, thereby maintaining the stability of nitrogen supply during rice growth.

[0128] In detail, real-time transmittance data for adjacent time points (e.g., daily) are obtained. This data is collected by a light intensity sensor array and then processed by time series filtering. For the transmittance T(n) and T(n+1) on day n and day n+1, the absolute value of the transmittance change rate is calculated as |T(n+1)-T(n)|, in units of % / day.

[0129] Furthermore, based on the general nutrient requirements of rice in its early growth stages, an initial interval between adjacent fertilizations was set, such as 3 days. The current rate of change in light transmittance was compared with the rate of change in the previous time interval. If the absolute value of the current rate of change increased, it indicated that the canopy structure was changing more rapidly, and the rice's demand for nitrogen might be increasing; if the absolute value of the rate of change decreased, it indicated that the canopy structure was changing more slowly, and the demand for nitrogen was relatively stable.

[0130] Furthermore, when the absolute value of the rate of change in light transmittance increases, the time interval between adjacent fertilizations should be shortened by 1 day (e.g., from 3 days to 2 days) to replenish nitrogen in a timely manner; when the absolute value of the rate of change decreases, the interval should be extended by 1 day (e.g., from 3 days to 4 days) to avoid excessive nitrogen application.

[0131] Furthermore, a specific date within the current growth period is used as the starting point for the first fertilization, such as the 15th day of the peak tillering period. Based on the adjusted intervals between adjacent fertilizations, the timing of subsequent fertilizations is calculated sequentially. For example, if the first fertilization is on the 15th day, with an interval of 2 days, the subsequent timings would be the 17th day, the 19th day, and so on, forming a set of fertilization timings.

[0132] Furthermore, the total amount of nitrogen applied in each operation is allocated to each time point in the set of fertilization time points to ensure that the amount of nitrogen applied at each fertilization time point is equal, such as applying 4 grams of nitrogen per square meter each time. The fertilization time point, the amount of nitrogen applied each time, and the duration determined according to soil texture (e.g., longer duration for clay soil and shorter duration for sandy soil) are integrated into a nitrogen application sequence instruction, which is stored and output in the form of structured data, such as {"fertilization time": [day 15, day 17, ...], "nitrogen application amount": [4 g / m²] 2 4g / m 2 ,…], “Duration”: [5h,5h,…]}.

[0133] In summary, this step dynamically adjusts the fertilization time interval based on the rate of change in light transmittance, and monitors the changes in light transmittance in real time to adjust the fertilization sequence accordingly. This ensures that the timing of fertilization matches the rhythm of rice's nitrogen demand, avoiding nitrogen supply delays or excesses caused by changes in canopy structure. It improves nitrogen fertilizer utilization efficiency, reduces nitrogen loss and waste, and thus effectively enhances the accuracy of light-nitrogen coupling regulation of the canopy in low- and medium-yield hybrid rice fields.

[0134] S4. Execute the nitrogen application timing command and simultaneously monitor the nitrogen accumulation in the leaves of hybrid rice.

[0135] In this embodiment of the invention, the synchronous monitoring of leaf nitrogen accumulation in hybrid rice includes:

[0136] After each nitrogen application, functional leaf samples were collected from the middle of the hybrid rice canopy.

[0137] The functional leaf sample was decolorized and dried to obtain dry matter;

[0138] The nitrogen content of the dry matter was determined by the micro Kjeldahl method, and the nitrogen accumulation per unit area of ​​the leaf was calculated in combination with the sample leaf area.

[0139] In detail, the monitoring and verification of nitrogen accumulation in the leaves includes:

[0140] When the coefficient of variation of continuously monitored leaf nitrogen accumulation exceeds a preset variation threshold, a resampling mechanism is triggered.

[0141] Backup leaf samples were recollected at the same location in the hybrid rice canopy layer.

[0142] If the difference between the measured value of the backup leaf sample and the original sample exceeds the tolerance range, laboratory arbitration testing is activated, and the leaf nitrogen accumulation record is updated with the arbitration test result.

[0143] In this embodiment of the invention, the steps for determining the duration of the nitrogen application timing command are as follows:

[0144] Get the current soil infiltration rate category:

[0145] When the soil is clayey, extend the duration of nitrogen application.

[0146] When the soil is sandy, shorten the duration of nitrogen application.

[0147] In detail, the nitrogen application timing instruction refers to the specific operational instructions that include the fertilization time point, the amount of nitrogen applied each time, and the duration of fertilization. It is dynamically generated by combining the target nitrogen application amount with the light transmittance change rate and is used to guide actual fertilization operations. Simultaneous monitoring refers to the real-time collection and measurement of nitrogen accumulation in hybrid rice leaves while performing nitrogen application operations, so as to achieve immediate feedback on fertilization effects.

[0148] In detail, functional leaf samples refer to leaves with full photosynthetic capacity selected from the middle of the hybrid rice canopy. The nitrogen accumulation of these leaves can accurately reflect the nitrogen nutrition status of the plant.

[0149] In detail, decolorization involves removing chlorophyll from leaf samples using chemical reagents (such as 95% ethanol) to avoid interference from pigments in subsequent nitrogen content determination, thus making the results more accurate. Drying involves placing leaf samples at a specific temperature (such as 105℃ for blanching and then 75℃) to dry to constant weight, removing moisture to obtain dry matter, which facilitates accurate nitrogen content determination. The micro-Kjeldahl method is a standard method for determining nitrogen content in organic compounds through digestion, distillation, and titration. It has high precision and is suitable for nitrogen analysis of trace samples such as leaves.

[0150] In detail, the nitrogen accumulation per unit area of ​​leaves refers to the mass of nitrogen contained in each square meter of leaves. It is calculated by combining the nitrogen content measurement value with the leaf area and is a key indicator for measuring the nitrogen nutrition status of plants.

[0151] In detail, the coefficient of variation is an indicator that measures the dispersion of continuous monitoring data. It is calculated as the ratio of the standard deviation to the mean of the data and is used to judge the stability and reliability of the monitoring data. The preset variation threshold is a pre-set critical value for the coefficient of variation. When the coefficient of variation of continuous monitoring data exceeds this value, it indicates abnormal data fluctuation and a resampling mechanism needs to be triggered.

[0152] In detail, the resampling mechanism refers to the procedure of re-collecting leaf samples at the same canopy location when monitoring data is abnormal, in order to eliminate the influence of single sampling errors on the results; the backup leaf sample is an additional sample collected and saved at the same time as the first sampling, used to repeat the measurement when needed to verify the accuracy of the initial measurement results; the tolerance range is the allowable difference limit between the measured values ​​of the backup sample and the original sample. If the difference exceeds this range, a more precise laboratory arbitration test needs to be initiated.

[0153] In detail, laboratory arbitration testing refers to commissioning a professional laboratory to use high-precision instruments (such as an elemental analyzer) to determine the nitrogen content of leaf samples, and the results are used as the basis for final data recording.

[0154] In detail, soil infiltration rate categories are classifications based on soil texture and its ability to absorb water. They are mainly divided into clay soil (low infiltration rate) and sandy soil (high infiltration rate) to determine the duration of nitrogen application. Clay soils are those with a high clay content, which have fine particles and slow water infiltration. When applying nitrogen, the duration of nitrogen application needs to be extended to avoid nitrogen accumulation on the surface. Sandy soils are those with a high sand content, which have loose particles and rapid water infiltration. When applying nitrogen, the duration of nitrogen application needs to be shortened to reduce nitrogen leaching loss.

[0155] Furthermore, based on the fertilization time point set in the nitrogen application sequence instruction, the fertilization equipment is started on preset dates (such as day 15, day 17, etc.) to ensure that the fertilization operation is synchronized with the rice growth cycle; according to the total amount of nitrogen application allocated in the instruction (such as 4 grams / square meter), nitrogen fertilizer is evenly applied through metering fertilization equipment (such as electric fertilizer applicators) to ensure that the amount of fertilizer applied each time is accurate and consistent; soil samples from the 0-20cm layer are collected, and the mechanical composition is determined by sieving: clay content >30% is identified as clay soil, and sand content >50% is identified as sandy soil; for clay soil, the duration of nitrogen application is extended to 4-6 hours (base duration 3 hours + extension amount), and for sandy soil, it is shortened to 1-2 hours (base duration - shortening amount), and the duration is adjusted by controlling the application rate of the fertilization equipment.

[0156] Furthermore, three days after each nitrogen application, choose a sunny day between 9:00 and 11:00, when the leaves are physiologically active and nitrogen is evenly distributed. Select five robust rice plants in the middle of the canopy and collect the third fully expanded functional leaf from the bottom. Take a 10cm*2cm sample from the middle of each leaf, avoiding the leaf tip and base.

[0157] In detail, the sample processing includes: immersing the leaf samples in a 95% ethanol solution and soaking them in a 50°C constant temperature water bath until the leaves turn completely white (about 2-3 hours) to remove pigments such as chlorophyll; removing the decolorized samples, rinsing the surface ethanol with deionized water, blotting the moisture with filter paper, placing them in an oven, first blanching at 105°C for 30 minutes, then drying at 75°C to constant weight (about 12-24 hours), and weighing the dry matter.

[0158] Further, weigh 0.5 g of dry matter sample and place it in a Kjeldahl flask. Add 3 g of potassium sulfate-copper sulfate mixed catalyst (K2SO4:CuSO4 = 10:1) and 5 mL of concentrated sulfuric acid. In a fume hood, use a Kjeldahl nitrogen analyzer to heat and digest until the solution is clear and transparent (about 2 hours) to convert organic nitrogen into ammonium sulfate. After cooling the digest, transfer it to a distillation apparatus, add excess sodium hydroxide solution to make it alkaline, heat and distill, and absorb the released ammonia gas with 2% boric acid solution. Titrate the absorbent with 0.01 mol / L hydrochloric acid standard solution, and use a methyl red-bromocresol green mixed indicator to determine the endpoint (the color changes from blue-green to gray-red). Record the amount of hydrochloric acid used.

[0159] In detail, the actual area of ​​the leaf sample is measured using a leaf area meter, or estimated using length * width * correction factor (0.85); the nitrogen content is calculated based on the titration results (N% = (V * C * 0.014) / m * 100%, where V is the volume of hydrochloric acid, C is the concentration, and m is the sample mass), then multiplied by the leaf area and converted to unit area (m²). 2 Nitrogen accumulation (g / m³) 2 ).

[0160] Furthermore, nitrogen accumulation data from five consecutive monitoring sessions (e.g., N1, N2, N3, N4, N5) are recorded, and the mean μ and standard deviation σ are calculated. The coefficient of variation (CV) is calculated as (σ / μ) * 100%. The preset variation threshold is 15%. If CV > 15%, a resampling mechanism is triggered.

[0161] Furthermore, the resampling process includes: collecting functional leaf samples from 10 rice plants near the original sampling location (error ≤ 50 cm), repeating the above sampling, processing, and measurement procedures, and obtaining the backup sample measurement value N. backup ; Calculate the difference rate between the backup sample and the original sample measurements as p = |N backup -N original | / N original *100%. If the difference rate is greater than 10%, the original sample and the backup sample will be sent to a third-party laboratory for arbitration testing using an elemental analyzer. The nitrogen accumulation record in the database will be updated based on the arbitration result.

[0162] In summary, this step precisely executes nitrogen application timing instructions and combines them with real-time monitoring of leaf nitrogen accumulation. Dynamically adjusting the duration of nitrogen application avoids nitrogen residue on the surface of clay soils or nitrogen leaching in sandy soils, improving nitrogen fertilizer use efficiency. Standardized sampling and measurement procedures ensure the reliability of nitrogen accumulation data, while a rigorous verification mechanism eliminates the interference of random errors on the control model, making subsequent model corrections more scientific. Ultimately, this achieves closed-loop optimization of light-nitrogen coupled control, improving the yield stability of hybrid rice in low- and medium-yield fields.

[0163] S5. Based on the dynamic deviation between the nitrogen accumulation in the leaves and the preset nitrogen accumulation threshold, the lag compensation relationship of the nitrogen demand model is corrected before the start of the next growth stage.

[0164] In this embodiment of the invention, the step of feeding back and correcting the lag compensation relationship of the nitrogen demand model before the start of the next reproductive stage includes:

[0165] Calculate the dynamic deviation between the nitrogen accumulation in the leaves and the preset nitrogen accumulation threshold;

[0166] When the dynamic deviation remains positive, decrease the daily value of the hysteresis compensation parameter;

[0167] When the dynamic deviation remains negative, increase the day value of the hysteresis compensation parameter;

[0168] The corrected lag compensation parameters are then input into the nitrogen demand model for the next reproductive stage.

[0169] A report on the correction of the lag compensation relationship is generated at the end of the heading period.

[0170] In detail, leaf nitrogen accumulation refers to the mass of nitrogen in a unit area of ​​hybrid rice leaves obtained through sampling and measurement. It reflects the absorption and accumulation of nitrogen during rice growth. The preset nitrogen accumulation threshold is a reference value for leaf nitrogen accumulation set in advance based on the characteristics of hybrid rice varieties, growth stages and high-yield targets. It is used to measure whether the actual nitrogen accumulation meets the growth requirements.

[0171] In detail, dynamic deviation is the difference between the nitrogen accumulation in the leaves and the preset nitrogen accumulation threshold, which is used to characterize the degree of deviation between the current nitrogen accumulation status and the target status; the hysteresis compensation parameter is the number of days shifted to correct the time lag relationship between real-time transmittance and nitrogen accumulation in the leaves, and its value affects the prediction accuracy of the nitrogen demand model.

[0172] In detail, the nitrogen demand model is a mathematical model based on the light-nitrogen coupling relationship, used to calculate the target nitrogen accumulation and nitrogen application rate required for hybrid rice growth based on the compensated light transmittance.

[0173] In detail, the growth stage refers to the different periods of growth and development of hybrid rice. This invention mainly involves key growth stages such as the tillering peak stage to the heading stage, and the nitrogen requirements of each stage are different.

[0174] In detail, the revision report is a summary document generated at the end of the heading stage, summarizing the process and effects of adjusting the lag compensation relationship. It is used to record the model optimization process and provide data reference.

[0175] Furthermore, leaf nitrogen accumulation data measured after each nitrogen application operation are extracted from the monitoring results of step S4, and preset nitrogen accumulation thresholds for the corresponding growth stages are retrieved. These preset thresholds are determined based on historical high-yield data of the rice variety; for example, the threshold for the peak tillering stage is 25-30 g / m². 2 The threshold for the heading stage is 30-35 g / m². 2 .

[0176] Furthermore, the dynamic deviation between the monitored leaf nitrogen accumulation and a preset threshold is calculated. For example, if a monitored value is 28 g / m³, the deviation is calculated. 2 The threshold is 30g / m 2 The dynamic deviation is then -2g / m 2 .

[0177] Furthermore, the dynamic deviation data are arranged in chronological order for multiple consecutive times (e.g., three consecutive times) to analyze their positive and negative trends, determining whether nitrogen accumulation is consistently above or below a threshold: When all three consecutive dynamic deviations are positive, it indicates that the current lag compensation parameter is causing the model's predicted nitrogen demand to be too high, and the number of days for the lag compensation parameter needs to be reduced. The adjustment increment is 1 day each time, but not less than 1 day; for example, if the original parameter is 5 days, adjust it to 4 days. When all three consecutive dynamic deviations are negative, it indicates that the model's predicted nitrogen demand is too low, and the number of days for the lag compensation parameter needs to be increased. The adjustment increment is 1 day each time, but not exceeding 10 days; for example, if the original parameter is 5 days, adjust it to 6 days.

[0178] Furthermore, the hysteresis compensation parameter represents the physiological response lag time of the effect of transmittance on nitrogen accumulation. When nitrogen accumulation is consistently higher than the threshold, it indicates that the effect of transmittance change on nitrogen demand is faster than the model preset, so the lag time is shortened; conversely, the lag time is extended to match the actual physiological response.

[0179] Furthermore, at the end of the current growth stage (2-3 days before the start of the next growth stage), the revised lag compensation parameters are synchronized to the parameter library of the nitrogen demand model. For example, before the heading stage begins, the revised parameters for the peak tillering period (e.g., adjusted from 5 days to 4 days) are input into the model.

[0180] Furthermore, the nitrogen demand model automatically updates the calculation logic for compensating for transmittance after receiving new parameters.

[0181] Furthermore, the report includes: recording the adjustment time, pre-adjustment value, post-adjustment value, and adjustment reason (such as continuous deviation trend) of the lag compensation parameters before the start of each growth stage; and summarizing the dynamic deviation distribution of all leaf nitrogen accumulation monitoring data during the heading period, including average deviation, maximum deviation, and positive and negative deviation frequencies.

[0182] Furthermore, within 24 hours after the heading period ends, the system automatically extracts data from the database and generates a PDF report, which is stored on the system server and pushed to the user terminal.

[0183] In summary, this step of dynamic bias analysis and lag compensation parameter correction solves the prediction bias problem caused by the fixed physiological response lag time in nitrogen demand models. By adjusting model parameters in real time based on nitrogen accumulation feedback, the model can adapt to the light and nitrogen response characteristics of hybrid rice under different growth stages and environmental conditions. This avoids nitrogen application deviations caused by inaccurate model lag compensation, improves the accuracy of nitrogen demand prediction and the adaptability of the control system, and ultimately achieves continuous optimization of light-nitrogen coupling control efficiency.

[0184] like Figure 2 The diagram shown is a functional block diagram of a high-yield regulation system for canopy light-nitrogen coupling in low- and medium-yield hybrid rice fields provided in an embodiment of the present invention.

[0185] The canopy-based light-nitrogen coupling high-yield regulation system 100 for low- and medium-yield hybrid rice described in this invention can be installed in an electronic device. Depending on the functions implemented, the system 100 may include a real-time transmittance acquisition module 101, a nitrogen demand model construction module 102, a nitrogen application timing command generation module 103, a leaf nitrogen accumulation monitoring module 104, and a lag compensation relationship correction module 105. The module described in this invention can also be referred to as a unit, which is a series of computer program segments that can be executed by an electronic device processor and perform a fixed function, stored in the electronic device's memory.

[0186] In this embodiment, the functions of each module / unit are as follows:

[0187] The real-time transmittance acquisition module 101 is used to acquire the real-time transmittance of the hybrid rice canopy during the critical growth period from the tillering stage to the heading stage.

[0188] The nitrogen demand model construction module 102 is used to construct a nitrogen demand model and output the target nitrogen application rate based on the lag compensation relationship between the real-time light transmittance and the nitrogen accumulation in the leaves.

[0189] The nitrogen application timing instruction generation module 103 is used to generate a nitrogen application timing instruction based on the target nitrogen application amount. The nitrogen application timing instruction includes the fertilization time point and duration, and the time interval between adjacent fertilizations is dynamically adjusted by the transmittance change rate.

[0190] The leaf nitrogen accumulation monitoring module 104 is used to execute the nitrogen application timing command and simultaneously monitor the leaf nitrogen accumulation of hybrid rice.

[0191] The lag compensation relationship correction module 105 is used to correct the lag compensation relationship of the nitrogen demand model before the start of the next growth stage based on the dynamic deviation between the leaf nitrogen accumulation and the preset nitrogen accumulation threshold.

[0192] In the several embodiments provided by this invention, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the system embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and other division methods may be used in actual implementation.

[0193] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0194] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in the form of hardware plus software functional modules.

[0195] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0196] The embodiments of this application can acquire and process relevant data based on artificial intelligence technology. Artificial intelligence is the theory, method, technology, and application system that uses digital computers or machines controlled by digital computers to simulate, extend, and expand human intelligence, perceive the environment, acquire knowledge, and use that knowledge to obtain optimal results.

[0197] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields, characterized in that, The method includes: S1. Obtain the real-time light transmittance of the hybrid rice canopy during the critical growth period from the tillering stage to the heading stage; S2. Based on the lag compensation relationship between the real-time transmittance and leaf nitrogen accumulation, the process includes: obtaining historical transmittance and corresponding measured leaf nitrogen accumulation values ​​for historical growth periods; shifting the historical transmittance backward by a preset number of days to align with the measured leaf nitrogen accumulation values; calculating the correlation coefficient between the shifted historical transmittance and leaf nitrogen accumulation, and iteratively adjusting the shift number of days until the correlation coefficient reaches its maximum value; using the shift number of days corresponding to the maximum correlation coefficient as the lag compensation parameter; constructing a nitrogen demand model and outputting the target nitrogen application rate, including: shifting the real-time transmittance according to the lag compensation parameter to obtain the compensated transmittance of the hybrid rice canopy; establishing a linear regression model between the compensated transmittance and the target nitrogen accumulation. ,in, It compensates for light transmittance. It is the photo-nitrogen conversion efficiency factor. It is the target nitrogen accumulation amount. It is the soil available nitrogen content measured before sowing. It is residual nitrogen that was not utilized in the early stages. This represents the ammonia volatilization loss; input the current light transmittance into the linear regression model, and the target nitrogen application rate will be output. S3. Generate a nitrogen application timing instruction based on the target nitrogen application amount. The nitrogen application timing instruction includes the fertilization time point and duration, and the time interval between adjacent fertilizations is dynamically adjusted by the transmittance change rate. S4. Execute the nitrogen application timing command and simultaneously monitor the nitrogen accumulation in the leaves of hybrid rice; S5. Based on the dynamic deviation between the nitrogen accumulation in the leaves and the preset nitrogen accumulation threshold, the lag compensation relationship of the nitrogen demand model is corrected before the start of the next growth stage.

2. The method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields as described in claim 1, characterized in that, The method of obtaining the real-time transmittance of the hybrid rice canopy includes: An array of light intensity sensors was deployed above the canopy of hybrid rice to collect the intensity of incident solar radiation. A transmission light sensor array was deployed symmetrically below the canopy of hybrid rice to collect the intensity of transmitted light penetrating the canopy. Calculate the instantaneous transmittance ratio based on the incident light intensity and the transmitted light intensity; The instantaneous transmittance ratio is subjected to time-series filtering to obtain the real-time transmittance of the hybrid rice canopy.

3. The method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields as described in claim 1, characterized in that, The step of generating nitrogen application timing instructions based on the target nitrogen application amount includes: The target nitrogen application rate is broken down into the total amount of several nitrogen application operations; Calculate the absolute value of the rate of change of transmittance at adjacent time points; When the absolute value of the rate of change of light transmittance increases, the time interval between adjacent fertilization applications should be shortened. When the absolute value of the rate of change of light transmittance decreases, the time interval between adjacent fertilization applications is extended. A set of fertilization time points for hybrid rice is generated based on dynamically adjusted time intervals, and an equal amount of nitrogen application is allocated to each fertilization time point in the set.

4. The method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields as described in claim 1, characterized in that, The synchronous monitoring of nitrogen accumulation in hybrid rice leaves includes: After each nitrogen application, functional leaf samples were collected from the middle of the hybrid rice canopy. The functional leaf sample was decolorized and dried to obtain dry matter; The nitrogen content of the dry matter was determined by the micro Kjeldahl method, and the nitrogen accumulation per unit area of ​​the leaf was calculated in combination with the sample leaf area.

5. The method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields as described in claim 4, characterized in that, The monitoring and verification of nitrogen accumulation in the leaves includes: When the coefficient of variation of continuously monitored leaf nitrogen accumulation exceeds a preset variation threshold, a resampling mechanism is triggered. Backup leaf samples were recollected at the same location in the hybrid rice canopy layer. If the difference between the measured value of the backup leaf sample and the original sample exceeds the tolerance range, laboratory arbitration testing is activated, and the leaf nitrogen accumulation record is updated with the arbitration test result.

6. The method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields as described in claim 1, characterized in that, The steps for determining the duration of the nitrogen application timing command are as follows: Get the current soil infiltration rate category: When the soil is clayey, extend the duration of nitrogen application. When the soil is sandy, shorten the duration of nitrogen application.

7. The method for high-yield regulation of hybrid rice canopy light-nitrogen coupling in low- and medium-yield fields as described in claim 1, characterized in that, The process of providing feedback and correction to the lag compensation relationship of the nitrogen demand model before the start of the next reproductive stage includes: Calculate the dynamic deviation between the nitrogen accumulation in the leaves and the preset nitrogen accumulation threshold; When the dynamic deviation remains positive, decrease the daily value of the hysteresis compensation parameter; When the dynamic deviation remains negative, increase the day value of the hysteresis compensation parameter; The corrected lag compensation parameters are then input into the nitrogen demand model for the next reproductive stage. A report on the correction of the lag compensation relationship is generated at the end of the heading period.

8. A high-yield regulation system for canopy light-nitrogen coupling in hybrid rice fields with medium and low yields, characterized in that, The system includes: The real-time transmittance acquisition module is used to acquire the real-time transmittance of the hybrid rice canopy during the critical growth period from the tillering stage to the heading stage. A nitrogen demand model construction module is used to construct a nitrogen demand model based on the lag compensation relationship between real-time transmittance and leaf nitrogen accumulation. This includes: obtaining historical transmittance and corresponding measured leaf nitrogen accumulation values ​​for different growth periods; shifting the historical transmittance backward by a preset number of days to align with the measured leaf nitrogen accumulation values; calculating the correlation coefficient between the shifted historical transmittance and leaf nitrogen accumulation, and iteratively adjusting the shift number of days until the correlation coefficient reaches its maximum value; using the shift number of days corresponding to the maximum correlation coefficient as the lag compensation parameter; and constructing a nitrogen demand model and outputting the target nitrogen application rate, including: shifting the real-time transmittance according to the lag compensation parameter to obtain the compensated transmittance of the hybrid rice canopy; and establishing a linear regression model between the compensated transmittance and the target nitrogen accumulation. ,in, It compensates for light transmittance. It is the photo-nitrogen conversion efficiency factor. It is the target nitrogen accumulation amount. It is the soil available nitrogen content measured before sowing. It is residual nitrogen that was not utilized in the early stages. This represents the ammonia volatilization loss; input the current light transmittance into the linear regression model, and the target nitrogen application rate will be output. The nitrogen application timing instruction generation module is used to generate nitrogen application timing instructions based on the target nitrogen application amount. The nitrogen application timing instructions include the fertilization time point and duration, and the time interval between adjacent fertilizations is dynamically adjusted by the transmittance change rate. The leaf nitrogen accumulation monitoring module is used to execute the nitrogen application timing command and simultaneously monitor the leaf nitrogen accumulation of hybrid rice. The lag compensation relationship correction module is used to correct the lag compensation relationship of the nitrogen demand model before the start of the next growth stage based on the dynamic deviation between the nitrogen accumulation of the leaves and the preset nitrogen accumulation threshold.

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