A micro-sprinkling water supply control method for rice hard ground hard disk seedling raising

Abstract

The application discloses a micro-spraying water supply control method for rice hard-hard disk seedling raising, and belongs to the technical field of agricultural intelligent irrigation. The method comprises the following steps: acquiring rising edge time domain parameters of output signals of each light sensor when the light sensor responds to environmental light for the first time in a day, wherein the rising edge time domain parameters comprise a response delay time and a rising slope; and determining a leaf surface dew enrichment level of each water supply partition according to the rising edge time domain parameters, wherein the greater the response delay time and the smaller the rising slope, the higher the leaf surface dew enrichment level. The application realizes the perception of the leaf surface dew enrichment level without additional hardware by multiplexing the rising edge time domain characteristics of the light sensor, and jointly calculates the dew replaceable irrigation amount and the actual water deficit of the root system, thereby avoiding the risk of excessive irrigation diseases under high dew conditions, and ensuring sufficient water compensation for the stress partition.

Description

Technical Field

[0001] This application relates to the field of agricultural intelligent irrigation technology, and in particular to a micro-sprinkler irrigation water supply control method for rice seedling raising on hard ground. Background Technology

[0002] Rice seedling raising is a crucial step in rice production. Hard-ground hard-plate seedling raising technology is widely used in major rice-producing areas due to its advantages such as ease of mechanization and high-quality seedlings. Micro-sprinkler irrigation, as the main irrigation method for hard-ground hard-plate seedling raising, uses micro-sprinklers to evenly spray water onto the surface of the seedling hard plate, providing a suitable moisture environment for seedling growth.

[0003] However, existing micro-sprinkler irrigation control systems generally adopt a fixed irrigation strategy with fixed time and quantity, failing to fully consider the dynamic coupling effects of multiple factors such as leaf dew status, substrate type differences, and changes in meteorological conditions during the seedling raising process. In actual production, if micro-sprinkler irrigation is started at a fixed cycle when leaf dew is abundant in the early morning, it will cause the leaf surface to be in a high humidity state for a long time, which can easily induce diseases such as sheath blight and rice blast. The water retention characteristics of seedling trays made of different materials (plastic trays and paper trays) vary significantly. Using a uniform water requirement threshold will result in insufficient irrigation in the plastic tray seedling area or excessive irrigation in the paper tray seedling area. In addition, the evaporation dynamics of dew change in high-altitude and low-pressure environments, and a fixed irrigation duration is difficult to adapt to the changes in root transpiration requirements. Summary of the Invention

[0004] The purpose of this application is to provide a micro-sprinkler irrigation water supply control method for rice seedling raising on hard ground, so as to solve the technical problems of existing fixed-cycle irrigation strategies that ignore the dynamic balance between leaf dew and root water demand, fail to distinguish the water retention characteristics of hard ground materials, and lack the ability to adapt to meteorological environments.

[0005] This application provides a micro-sprinkler irrigation water supply control method for rice seedling raising on hard ground. The seedling raising site is pre-divided into several water supply zones, each of which is equipped with a light sensor and a substrate moisture content sensor. Seedling hard disks are laid in the water supply zones. The method includes the following steps: The rising edge time-domain parameters of the output signal of each of the light sensors when they first respond to ambient light on the same day are obtained. The rising edge time-domain parameters include response delay time and rising slope. Based on the rising edge time domain parameters, the leaf dew enrichment level of each water supply zone is determined, wherein the greater the response delay time and the smaller the rising slope, the higher the leaf dew enrichment level. Obtain the measured values ​​of substrate moisture content in each water supply zone, and determine the stress marking status of each water supply zone based on the comparison results between the measured values ​​of substrate moisture content and the preset root development water requirement threshold. The root development water requirement threshold is determined according to the type of seedling hard disk substrate. Based on the leaf dew enrichment level and the stress marker status, the comprehensive irrigation demand of each water supply zone is calculated. The higher the leaf dew enrichment level, the lower the comprehensive irrigation demand. When the stress marker status is stress, the comprehensive irrigation demand is increased. The increase is positively correlated with the difference between the root development water requirement threshold and the measured value of the substrate moisture content. Arrange the water supply priority of each water supply zone in descending order of the comprehensive irrigation demand; According to the water supply priority, the micro-sprinkler irrigation of the corresponding water supply zones is turned on in sequence. The water supply zone with a large overall irrigation demand is configured with a longer single water supply duration and a shorter water supply interval than the water supply zone with a small overall irrigation demand.

[0006] Therefore, this invention achieves leaf dew enrichment level detection without additional hardware by reusing the rising edge temporal characteristics of the light sensor, couples the amount of dew that can be replaced by irrigation with the actual water deficit of the root system for calculation, and configures irrigation duration and frequency according to the demand, thereby realizing a dynamic balance between the leaf microenvironment and the water demand state of the root system, avoiding the risk of disease from over-irrigation under high dew conditions, while ensuring sufficient water compensation in the stress zone.

[0007] Furthermore, it achieved a dynamic balance between the leaf microenvironment and root water requirements, avoiding the risk of sheath blight and rice blast caused by excessive irrigation under high dew conditions. At the same time, it ensured that the water deficit in the stress zone was fully compensated, improving water resource utilization efficiency and seedling survival rate.

[0008] As a specific implementation method, determining the leaf dew enrichment level of each water supply zone based on the rising edge time domain parameters includes: Calculate the delay ratio between the response delay time and the preset baseline delay time; Calculate the slope ratio between the rising slope and the preset reference slope; The leaf dew enrichment level is determined based on the weighted composite index of the delay ratio and the slope ratio.

[0009] Based on the above, by weighted fusion of delay ratio and slope ratio, the response lag effect and signal smoothing effect caused by dew are quantitatively integrated, thereby improving the accuracy and stability of dew enrichment level determination.

[0010] As a specific implementation method, the method further includes: obtaining the duration of the dark state of each water supply zone before the first response to ambient light on the same day; and correcting the judgment threshold of the leaf dew enrichment level according to the duration of the dark state, wherein the longer the duration of the dark state, the more lenient the corrected judgment threshold is, so as to avoid overjudgment of dew due to low temperature during long nights.

[0011] By utilizing the duration of dark conditions to identify long nights and low temperatures, and by relaxing the judgment threshold to eliminate sensor response distortion and misjudgment caused by low temperatures, the system effectively distinguishes between real dew accumulation and low-temperature illusions. This avoids overjudging dew under long night conditions in spring, prevents root drought stress caused by incorrect reduction of irrigation, and ensures consistency between the high dew level judgment results and the actual leaf condition.

[0012] As one specific implementation, the substrate type of the seedling raising hard disk includes plastic hard disks and paper hard disks, and the root development water requirement threshold of the plastic hard disk is higher than that of the paper hard disk.

[0013] Based on the physical water retention characteristics of different hard disk materials, the water requirement threshold for root development is set separately. This avoids underestimating irrigation needs due to the poor water retention and rapid evaporation of plastic hard disks, and also prevents substrate compaction and root hypoxia caused by over-irrigation of paper hard disks due to their good water retention. It achieves accurate stress determination that matches the hard disk material and improves irrigation adaptability under different hard disk seedling raising conditions.

[0014] As a specific implementation method, after sequentially activating the micro-sprinkler irrigation in the corresponding water supply zones, the method further includes: obtaining a stable value of substrate moisture content within a preset time after irrigation stops; calculating the difference between the stable value of substrate moisture content and the measured value of substrate moisture content before irrigation to obtain the actual infiltration water volume; and adjusting the root development water requirement threshold for the next irrigation cycle based on the ratio of the actual infiltration water volume to the theoretical water supply volume, wherein the theoretical water supply volume is determined by the product of the rated flow rate of the micro-sprinkler head and the duration of a single water supply, and when the ratio is lower than the preset lower limit of infiltration, the root development water requirement threshold is increased.

[0015] Through closed-loop feedback between actual infiltration and theoretical water supply, the system dynamically identifies the decline in infiltration efficiency caused by substrate compaction or nozzle blockage, and automatically adjusts the water demand threshold for the next cycle to compensate for it. This avoids misjudging that irrigation needs have been met due to a decrease in infiltration efficiency, and ensures the stability of root water supply during long-term operation.

[0016] As a specific implementation method, when there are multiple water supply zones with the same comprehensive irrigation demand, the method further includes: obtaining the ambient temperature of each water supply zone with the same demand when it first responds to ambient light on the same day; determining the opening order of the water supply zones with the same demand based on the ambient temperature, wherein the water supply zone with the lower ambient temperature is opened earlier.

[0017] It should be noted that by introducing a fine-grained sorting of water supply zones with the same demand, priority is given to ensuring the irrigation timeliness of low-temperature zones, avoiding root physiological drought caused by delayed irrigation in low temperatures. At the same time, the warming effect of sunlight after early irrigation promotes the evaporation of dew in low-temperature zones, shortening the duration of high humidity on the leaves.

[0018] As a specific implementation, the rising edge time domain parameter also includes a frequency domain attenuation parameter, which is obtained by extracting the high-frequency energy ratio after the output signal is subjected to a short-time Fourier transform. The larger the response delay time, the smaller the rising slope, and the lower the high-frequency energy ratio, the higher the leaf surface dew enrichment level.

[0019] It should be noted that by introducing frequency domain features for cross-validation of time domain determination, the probability of misjudgment caused by sensor noise or instantaneous cloud cover interference of a single time domain parameter is effectively reduced, thereby improving the robustness and accuracy of dew enrichment level determination.

[0020] As a specific implementation method, the method further includes: obtaining the leaf dew enrichment level sequence of each water supply zone within a preset historical period, calculating the dew inertia index of each water supply zone, wherein the dew inertia index characterizes the spatiotemporal stability of the dew enrichment degree of the corresponding water supply zone; the calculation of the comprehensive irrigation demand is also related to the dew inertia index, and the larger the dew inertia index, the more significant the weight of the current leaf dew enrichment level on the comprehensive irrigation demand.

[0021] Specifically, by using the spatiotemporal stability assessment of historical dew data, the confidence weight of the daily dew determination results is applied, which avoids the over-reliance on occasional high dew determinations in low-lying or poorly ventilated areas, and also prevents the erroneous underestimation of irrigation amounts in occasional low dew determinations in well-ventilated areas, thus achieving adaptive fusion of zonal geographical characteristics and real-time perception.

[0022] As a specific implementation method, the duration of a single water supply is determined based on the ratio of the comprehensive irrigation demand to the preset unit demand water volume; the water supply interval is determined based on the combined relationship between the comprehensive irrigation demand and the cumulative sunshine duration of the day, wherein the longer the cumulative sunshine duration of the day, the shorter the water supply interval.

[0023] Specifically, by configuring different durations based on the amount of water demand, the root water deficit in high-demand zones is quickly and fully compensated. At the same time, the watering frequency is adjusted by using the feedback of sunshine duration on evaporation intensity, avoiding excessively dry substrate due to long intervals during periods of intense sunshine, thus achieving synchronous matching between irrigation rhythm and crop transpiration rhythm.

[0024] As one specific implementation method, it also includes: Obtain the ambient air pressure value of each water supply zone at the first response to ambient light on the same day; Based on the ambient air pressure value and the leaf dew enrichment level, the dew balance evaporation pressure difference is calculated. The dew balance evaporation pressure difference is equal to the difference between the standard atmospheric pressure and the ambient air pressure value divided by the standard atmospheric pressure, and then divided by the sum of the dew enrichment level and one. The lower the ambient air pressure value, the larger the dew balance evaporation pressure difference; the higher the leaf dew enrichment level, the smaller the dew balance evaporation pressure difference. The duration of a single water supply is adjusted based on the dew balance evaporation pressure difference. The larger the dew balance evaporation pressure difference, the shorter the adjusted duration of a single water supply, in order to avoid oversaturation of leaf surface humidity under low air pressure conditions.

[0025] This invention, by introducing an assessment of the impact of air pressure on dew evaporation dynamics, corrects the problem of underestimating irrigation volume that may be caused by relying solely on dew enrichment levels in high-altitude, low-pressure environments. It adjusts long-term continuous irrigation into a short-term, long-pulse mode, which not only meets the enhanced root transpiration demand under low air pressure, but also promotes root penetration and stress resistance training through pulsed water supply.

[0026] The technical solutions provided by the embodiments of this disclosure have at least the following beneficial effects: This invention achieves leaf dew enrichment level detection without additional hardware by reusing the rising edge temporal characteristics of light sensors. It jointly calculates the amount of dew that can replace irrigation and the actual water deficit of the root system, and comprehensively adjusts irrigation parameters in multiple dimensions by considering the water retention characteristics of the hard disk material, environmental temperature ranking, historical dew inertia, solar transpiration rhythm, and atmospheric pressure evaporation dynamics. This achieves a dynamic balance between the leaf microenvironment and the water demand of the root system, avoiding the risk of disease from over-irrigation under high dew conditions. At the same time, it ensures sufficient water compensation in stress zones and closed-loop adaptive response to the decay of infiltration efficiency during long-term operation, effectively improving the accuracy of micro-sprinkler irrigation, water resource utilization efficiency, and adaptability to different altitudes and hard disk seedling raising environments with different materials. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the method structure of the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, this application provides a micro-sprinkler irrigation water supply control method for rice seedling raising on hard ground. The seedling raising site is pre-divided into several water supply zones, and each water supply zone is equipped with a light sensor and a substrate moisture content sensor. Seedling hard disks are laid in the water supply zones. The method includes the following core steps: First, the rising edge time domain parameters of the output signal of each light sensor when it first responds to ambient light on the same day are obtained. The rising edge time domain parameters include response delay time and rising slope. Then, based on the rising edge time domain parameters, the leaf dew enrichment level of each water supply zone is determined. The larger the response delay time and the smaller the rising slope, the higher the leaf dew enrichment level. Then, the measured values ​​of substrate moisture content in each water supply zone are obtained. Based on the comparison between the measured values ​​of substrate moisture content and the preset root development water requirement threshold, the stress marking status of each water supply zone is determined. The root development water requirement threshold is determined according to the type of seedling hard disk substrate. Subsequently, based on the leaf dew accumulation level and the stress marker status, the comprehensive irrigation demand of each water supply zone is calculated. A higher leaf dew accumulation level corresponds to a lower comprehensive irrigation demand. When the stress marker status indicates stress, the comprehensive irrigation demand is increased, and this increase is positively correlated with the difference between the root development water requirement threshold and the measured substrate moisture content. Then, the water supply priority of each water supply zone is arranged in descending order of comprehensive irrigation demand. Finally, based on the water supply priority, the corresponding micro-sprinkler irrigation is activated sequentially for each water supply zone. The water supply zone with a higher comprehensive irrigation demand is configured with a longer single water supply duration and a shorter water supply interval compared to the water supply zone with a lower comprehensive irrigation demand.

[0030] The entire method is deployed as a multi-sensor collaborative intelligent decision-making system within the seedling nursery. During the hardening-off stage from the three-leaf stage to transplanting, traditional timed irrigation often fails to address all issues: either watering before the morning dew dries, leading to disease, or watering only after the substrate has dried out in the afternoon, causing stress. This method utilizes existing light sensors in each irrigation zone to initiate a complete decision-making process upon first sensing changes in ambient light each morning, eliminating the need for manual field inspections.

[0031] After the method is started, the output signal of the light sensor is acquired first. It should be noted that if the sensor's photosensitive window is covered by a thin film of dew, the light transmittance decreases, and the transition of the signal from dark to bright states will be distorted, specifically manifested as a delayed response and a slower rise time. This characteristic allows for the direct reuse of existing light sensors to infer leaf dew status without the need for additional humidity sensors or image recognition equipment. This reduces hardware deployment costs and the complexity of multi-sensor data synchronization, while also avoiding fusion errors caused by inconsistent time bases of heterogeneous sensors.

[0032] Specifically, the first response of the day refers to the moment when the output signal of the light sensor first exceeds the preset trigger threshold from the previous dark state value. The response delay time is the time difference between the ambient light reaching the trigger condition and the signal actually starting to rise; the rise slope is the reciprocal of the time required for the signal to rise from 10% to 90% of the lower limit of the range. In one embodiment, the light sensor is a silicon photodiode type or photodiode type ambient light sensor with a sampling frequency of not less than ten times per second.

[0033] To quantify the dew accumulation level, the ratio of the response delay time to a preset baseline delay time and the ratio of the slope rise to a preset baseline slope are calculated. The leaf dew accumulation level is determined based on a weighted composite index of the delay ratio and the slope ratio. The weighted composite index is calculated by multiplying the delay ratio by a delay weighting coefficient and the slope ratio by a slope weighting coefficient, then adding the two products to obtain the weighted composite index value. The delay weighting coefficient is determined based on the sensor type and installation tilt angle, and is generally taken as 0.6; the slope weighting coefficient is generally taken as 0.4 to preferentially reflect the response hysteresis effect caused by dew. The rules for determining the leaf dew accumulation level are as follows: A weighted composite index value less than 0.5 is classified as Level 0; greater than or equal to 0.5 and less than 1.0 is classified as Level 1; greater than or equal to 1.0 and less than 1.5 is classified as Level 2; and greater than or equal to 1.5 is classified as Level 3. Level 3 is the highest dew accumulation level. The preset reference delay time and preset reference slope are obtained through calibration experiments on the same model of sensor under dry conditions, typically by averaging multiple measurements taken on a clear morning without dew coverage.

[0034] In one embodiment, the preset baseline delay time is set to 50 milliseconds, and the preset baseline slope is set to 200 millivolts per millisecond. These values ​​were obtained through calibration measurements of the same type of light sensor under dry conditions for seven consecutive mornings. The arithmetic mean of the seven-day measurements was 49 milliseconds and 202 millivolts per millisecond, with standard deviations of 3 milliseconds and 12 millivolts per millisecond, respectively. These values ​​were rounded down to the nearest integer and used as the baseline value. By weighted fusion of the delay ratio and the slope ratio, the response lag effect and signal smoothing effect caused by dew are quantified and integrated, improving the accuracy and stability of dew enrichment level determination.

[0035] It should be noted that the aforementioned weighted composite index is essentially a linear weighted sum of the delay ratio and the slope ratio, rather than a product operation in the mathematical sense. The term "weighted composite index" is used to accurately reflect the comprehensive quantitative result after the two time-domain features are fused by weights.

[0036] In one embodiment, under typical spring seedling raising conditions in the Jiangnan region, the light sensor first responds around 6:00 AM. When the measured response delay reaches 150 milliseconds and the rise rate drops to 60 millivolts per millisecond, the delay ratio is 3, the slope ratio is 0.3, and the weighted composite index is 1.92, classifying it as level three dew enrichment. At this time, the leaf surface dew thickness is estimated to be above 0.3 millimeters. This thickness estimate is obtained by linear regression calibration using the sensor response characteristics and the measured dew thickness using the standard graduated cylinder method, with a correlation coefficient exceeding 0.85. If micro-sprinkler irrigation is directly applied, the leaf surface will remain in a high-humidity state for an extended period, easily inducing sheath blight and rice blast.

[0037] To avoid overjudging dew due to prolonged low temperatures at night, the method also introduces a correction mechanism for the duration of the dark state. The duration of the dark state for each water supply zone before its first response to ambient light on that day is obtained; that is, the time span from the moment the light sensor output signal last fell below the trigger threshold the previous day to the moment it first rose above the trigger threshold on the current day. The judgment thresholds for each level of leaf dew accumulation are corrected based on the duration of the dark state. The longer the duration of the dark state, the more lenient the corrected judgment thresholds. This is because under prolonged low temperatures at night, even if the actual dew accumulation is not high, the low temperature can cause the sensor response to slow down, creating a false impression of dew coverage. The correction rule is as follows: When the duration of darkness is 8 hours or less, the judgment threshold remains unchanged; when the duration of darkness is greater than 8 hours but less than or equal to 10 hours, the judgment threshold for each level is relaxed by 10%; when the duration of darkness is greater than 10 hours but less than or equal to 12 hours, the judgment threshold for each level is relaxed by 20%; and when the duration of darkness is greater than 12 hours, the judgment threshold for each level is relaxed by 30%. This adjustment range was determined through comparative testing at three different latitude test sites (28°N, 32°N, and 36°N) during the spring seedling stage. The test period was 21 consecutive days, and the consistency between the duration of darkness and the actual dew state measured by the standard humidity sensor was recorded daily. The results showed that the above segmented correction could reduce the dew misjudgment rate under long nights and low temperatures from 23% to below 7%. This correction mechanism effectively distinguishes between actual dew accumulation and sensor response distortion caused by low temperature, ensuring that the high dew level judgment result is consistent with the actual leaf surface state and preventing root drought caused by erroneous reduction in irrigation due to overjudgment.

[0038] While determining the leaf dew enrichment level, the method simultaneously acquired measured values ​​of substrate moisture content for each water supply zone. The substrate moisture sensor, employing either frequency domain reflectometry or time domain reflectometry probes, was inserted approximately two to three centimeters into the substrate of the seedling tray, corresponding to the dense root zone of the rice seedlings. After acquiring the measured substrate moisture content, it was compared with a preset root development water requirement threshold to determine the stress labeling status.

[0039] The seedling tray substrate types include plastic trays and paper trays. The root development water requirement threshold for plastic trays is higher than that for paper trays. This is because plastic trays have poor water retention, resulting in rapid water evaporation and drastic changes in the water gradient around the roots, requiring a higher substrate moisture content to ensure normal root development. Paper trays, on the other hand, have a certain water absorption and retention capacity, allowing for a lower root development water requirement threshold to avoid substrate compaction and root hypoxia caused by over-irrigation. In one embodiment, the root development water requirement threshold is set at 25% to 30% of the substrate volume moisture content for plastic trays and 18% to 22% for paper trays. This threshold range was determined through the following comparative experiments: Rice seedlings of the same variety were selected and sown in plastic and paper hard drives, respectively, and cultivated under identical environmental conditions. The correlation between substrate moisture content and seedling root activity (measured using the triphenyltetrazolium chloride reduction method) and root length density (measured using a root scanner) was measured daily. After 15 consecutive days of observation, the optimal substrate moisture content range for plastic hard drives was determined to be 25.3% to 29.7%, and for paper hard drives, 17.8% to 21.5%. These threshold ranges were obtained after rounding and expansion. By setting water requirement thresholds based on the different physical water retention characteristics of the hard drives, the irrigation needs of plastic hard drives (due to their poor water retention) were not underestimated, and the over-irrigation of paper hard drives (due to their good water retention) was prevented. This achieved precise stress assessment matched to the hard drive material.

[0040] When the measured substrate moisture content is lower than the root development water requirement threshold, the stress status is marked as stress; when it is equal to or higher than the threshold, it is marked as normal. The stress status is a binary logic label. Stress indicates that the current substrate moisture content is insufficient to maintain normal root physiological metabolism, the seedling root water absorption rate is lower than the transpiration rate, and cell turgor pressure begins to decrease, requiring irrigation to restore root function. Normal indicates that the current moisture level is sufficient to meet root transpiration requirements, cell turgor pressure remains stable, and no additional intervention is needed. The determination of the stress status is not a simple binary logic but rather includes a hysteresis interval to avoid frequent switching caused by sensor noise.

[0041] The hysteresis interval is set according to the following rules: a stress flag is triggered when the measured value drops from above the threshold to 95% below the threshold, and the stress flag is released when the measured value rises from below the threshold to 105% above the threshold. This hysteresis range is determined through a 30-day output stability test of the matrix moisture content sensor. During the test, the standard deviation of the sensor output value is approximately 1% of the threshold, and five times the standard deviation is used as the hysteresis interval to cover noise fluctuations of over 99%. In one embodiment, the threshold for plastic hard drives is 27%, so a stress flag is triggered when the measured value drops to 25.65%, and the stress is released when it rises back to 28.35%; the threshold for paper hard drives is 20%, so a stress flag is triggered when the measured value drops to 19%, and the stress is released when it rises back to 21%.

[0042] The comprehensive irrigation demand is calculated as a joint function of leaf dew enrichment level and stress labeling state. In one embodiment, the comprehensive irrigation demand is calculated according to the following formula: the comprehensive irrigation demand equals the base demand multiplied by the dew correction factor plus the stress adjustment. The base demand is equal to the standard irrigation volume when there is no dew cover and the substrate moisture content reaches the root development water requirement threshold, and is determined by a combination of sprinkler flow rate, coverage area, and soil infiltration rate, typically taken as 0.5 to 1.0 cubic meters per 100 square meters. The dew correction factor is set as follows: 1.0 for level 0 dew enrichment, 0.8 for level 1 dew enrichment, 0.6 for level 2 dew enrichment, and 0.4 for level 3 dew enrichment. The stress-induced adjustment is equal to the root development water requirement threshold minus the measured substrate moisture content, multiplied by the substrate saturated water-holding capacity coefficient. The substrate saturated water-holding capacity coefficient is determined based on the porosity of the hard drive material: 0.8 to 1.0 for plastic hard drives and 1.0 to 1.2 for paper hard drives. The higher the porosity, the closer the coefficient is to the upper limit. This coupled calculation combines the natural physiological characteristic of leaf dew replacing irrigation with the actual water deficit state of the root system. It avoids leaf diseases and root hypoxia caused by excessive irrigation under high dew conditions, while ensuring sufficient compensation for the water deficit in the stress zone, achieving a dynamic balance between dew resource utilization and root water requirement assurance.

[0043] The water supply priority of each water supply zone is arranged in descending order of comprehensive irrigation demand. This prioritization ensures that the most water-scarce zones receive irrigation resources first, avoiding insufficient water supply to distant zones due to water pressure decay. In one embodiment, in a large seedling nursery covering twenty water supply zones, after ranking by comprehensive irrigation demand, the top five zones receive the first batch of irrigation, the sixth to tenth zones receive the second batch, and so on, with an interval of fifteen to twenty minutes between each batch to allow for pipeline pressure recovery and substrate moisture infiltration.

[0044] Micro-sprinkler irrigation is activated sequentially according to water supply priority for the corresponding water supply zones. Water supply zones with higher overall irrigation demand are configured with longer single-water supply durations and shorter water supply intervals compared to zones with lower overall irrigation demand. The duration of a single water supply is determined based on the ratio of overall irrigation demand to a preset unit demand. The preset unit demand refers to the standard amount of water required to raise the substrate moisture content from its current value to the root development water threshold, calculated comprehensively from sprinkler flow rate, coverage area, and soil infiltration rate, typically taken as 0.5 to 1.0 cubic meters per 100 square meters, with a sprinkler flow rate of 2 to 4 cubic meters per hour.

[0045] The water supply interval is determined according to the following rules: First, calculate the sunshine correction factor. When the cumulative sunshine duration of a day is less than or equal to two hours, the sunshine correction factor is 1.2; when the cumulative sunshine duration of a day is greater than two hours and less than or equal to four hours, the sunshine correction factor is 1.0; when the cumulative sunshine duration of a day is greater than four hours and less than or equal to six hours, the sunshine correction factor is 0.85. When the cumulative sunshine duration exceeds six hours, the sunshine correction factor is set to 0.7. The actual water supply interval is then obtained by multiplying the base interval by the sunshine correction factor. The base interval is determined based on the comprehensive irrigation demand: 30 minutes when the demand is greater than or equal to 80% of the base demand; 45 minutes when the demand is greater than or equal to 50% but less than 80%; and 60 minutes when the demand is less than 50%. The calculation of the cumulative sunshine duration begins from the moment the light sensor first falls below the trigger threshold the previous day, up to the calculation time of the day, representing the cumulative time the light intensity is above the photosynthetic light compensation point. The photosynthetic light compensation point is determined based on the light response characteristics of the rice variety, generally ranging from 30 to 50 micromoles per square meter per second, or referring to the measured values ​​for specific varieties.

[0046] In one embodiment, when the cumulative sunshine duration exceeds six hours, the watering interval is shortened by 15% to 30% from the baseline interval. This shortening is determined by continuously monitoring the rate of substrate moisture content decay under different sunshine durations. The monitoring period is fourteen consecutive days, with substrate moisture content changes recorded at different times each day. The results show that after more than six hours of sunshine, the rate of substrate moisture content decrease is approximately 1.4 times that of two to four hours of sunshine. Based on this, the sunshine correction factor is reduced from 1.0 to 0.7 to match the evaporation intensity. By configuring the intervals according to the demand, the root water deficit in high-demand zones is quickly and adequately compensated. At the same time, the watering frequency is adjusted by using the feedback of sunshine duration on evaporation intensity, avoiding excessive substrate drying due to excessively long intervals during periods of intense sunshine. This achieves synchronous matching between irrigation rhythm and crop transpiration rhythm.

[0047] In one embodiment, when the output signal of the light sensor remains below the trigger threshold or remains saturated within a preset sampling period, the sensor is marked as abnormal. The calculation of the dew enrichment level for that water supply zone is skipped, and the previous day's valid level value is directly used instead. A sensor maintenance prompt is also triggered. The rule for determining an abnormal state is: if the signal remains below 20% of the lower limit of the trigger threshold or remains above 95% of the upper limit of the range for 50 to 100 consecutive sampling periods, it is considered abnormal.

[0048] The previous day's valid grade value is stored in local non-volatile memory. After the daily irrigation decision is completed, it is overwritten and updated with the final grade determined for that day, and read and retrieved upon power-on. Once the signal returns to normal within three consecutive sampling cycles, the abnormality marker is removed, and real-time calculation resumes. Furthermore, if communication between the light sensor and the main controller is interrupted for more than three sampling cycles, it is also marked as an abnormal state, the previous day's valid grade value is used instead, and a communication failure log is recorded. When the output value of the substrate moisture content sensor changes by more than 30% of the threshold within two consecutive sampling periods and occurs three times consecutively, it is marked as a data jump anomaly. A moving average filter is then applied, and the arithmetic mean of the five most recent valid samples is taken as the current value. Simultaneously, a sensor calibration prompt is triggered, recommending standard moisture content calibration every 30 days. This anomaly handling mechanism ensures the continuity and reliability of irrigation decisions in the event of sensor failure or communication malfunctions, avoiding regional irrigation interruptions or misjudgments caused by single-point sensor failure.

[0049] In one embodiment, when processing early rice seedlings for double-cropping rice in the Yangtze River Basin, the prevalence of dew accumulation on leaves is widespread and prolonged due to frequent rain and large diurnal temperature variations in spring. Under these conditions, the light sensor first responds around 6:00 AM, with measured response delays generally exceeding 100 milliseconds and an ascent rate below 100 millivolts per millisecond. Most zones are classified as having level two or three dew accumulation. At this point, the baseline value for comprehensive irrigation demand is significantly reduced. Even if the substrate moisture content in some zones is slightly below the threshold, the adjusted comprehensive demand may still be less than 50% of that in normal zones. Based on this, the irrigation system prioritizes high-dew zones, providing only short-duration, low-frequency water replenishment after afternoon sunshine and dew evaporation. This effectively controls the incidence of damping-off and cottony rot, significantly reducing the disease rate compared to traditional timed irrigation methods.

[0050] When multiple water supply zones with the same comprehensive irrigation demand exist, the ambient temperature of each zone at the first response to ambient light on that day is obtained. The ambient temperature is acquired using a temperature and humidity probe deployed near the sensor, measured at a height of 50 centimeters above the ground, consistent with the height of the seedling leaf layer. The order in which zones with the same demand are activated is determined based on the ambient temperature. The specific sorting rule is as follows: the ambient temperature is divided into four intervals; a priority coefficient of 1.0 is used when the ambient temperature is less than or equal to 8 degrees Celsius; a priority coefficient of 0.8 is used when the ambient temperature is greater than 8 degrees Celsius but less than or equal to 12 degrees Celsius; a priority coefficient of 0.6 is used when the ambient temperature is greater than 12 degrees Celsius but less than or equal to 16 degrees Celsius; and a priority coefficient of 0.4 is used when the ambient temperature is greater than 16 degrees Celsius.

[0051] Zones with the same water demand are sorted according to their priority coefficients from largest to smallest, with those having the same coefficient arranged in the order of their water supply zone numbers. This temperature classification and priority coefficient were determined through comparative experiments on the root water absorption rate of rice seedlings (measured using the pressure chamber method to determine leaf water potential changes) and the leaf dew evaporation rate (measured using the weighing method) under different temperature conditions. The experiments were conducted in a temperature-controlled greenhouse, with four temperature gradients: 8°C, 12°C, 16°C, and 20°C. Each gradient was measured five times. The results showed that for every 4°C decrease in temperature, the root water absorption rate decreased by approximately 15%, and the leaf dew evaporation time increased by approximately 20%. Based on this, the aforementioned priority coefficients were set to ensure the timely irrigation of low-temperature zones. By introducing a fine-grained ranking based on temperature among water supply zones with the same demand, the timely irrigation of low-temperature zones is prioritized, avoiding root physiological drought caused by delayed irrigation in low temperatures. Simultaneously, the warming effect of sunlight after early irrigation promotes dew evaporation in low-temperature zones, shortening the duration of high humidity on the leaves.

[0052] To further improve the accuracy of dew detection, the rising edge time-domain parameter also includes a frequency-domain attenuation parameter. This frequency-domain attenuation parameter is obtained by extracting the high-frequency energy percentage after the output signal undergoes a short-time Fourier transform. The high-frequency energy percentage refers to the percentage of energy in the frequency band above the cutoff frequency relative to the total energy of the entire frequency band. This is because the smoothing effect of the dew film on the light signal is reflected not only in the time-domain response lag and slope decrease, but also in the attenuation of high-frequency components in the frequency domain. The thicker the dew, the more severe the scattering of the light signal, and the greater the loss of high-frequency details. A higher level of dew accumulation on the leaf surface is indicated by a larger response delay, a smaller rising slope, and a lower high-frequency energy percentage.

[0053] In one embodiment, the window length of the short-time Fourier transform is twice the response delay time, the overlap rate is 50%, and the cutoff frequency is one-fifth of the sensor sampling frequency or 0.5 times the upper limit of the effective frequency band of the signal. The high-frequency band refers to signal components with frequencies higher than the cutoff frequency. The high-frequency band energy proportion is equal to the sum of the energy of all frequency components higher than the cutoff frequency divided by the sum of the energy of all frequency components in the entire frequency band, and then multiplied by 100%. When the high-frequency band energy proportion is less than 15%, the level is increased by one level based on the original level. If the original level is already level three, it remains unchanged at level three, but the dew correction coefficient is further reduced from 0.4 to 0.3 to strengthen the suppression of irrigation under extreme high dew conditions. Introducing cross-validation of time-domain determination using frequency domain features effectively reduces the probability of misjudgment caused by sensor noise or instantaneous cloud cover interference of a single time-domain parameter, and improves the robustness and accuracy of dew enrichment level determination.

[0054] The method also introduces the concept of dew inertia index to characterize the spatiotemporal stability of dew enrichment in water supply zones. The leaf dew enrichment level sequence for each water supply zone within a preset historical period is obtained, and the normalized dew inertia index for each water supply zone is calculated. The normalized dew inertia index characterizes the spatiotemporal stability of dew enrichment in the corresponding water supply zone. Its calculation method is as follows: tracing back from the current day as day zero, the index decreasing weight coefficient for day i is equal to 2 - i divided by the square, where i takes values ​​of zero, one, two, up to the total number of days in the historical period minus one. The dew enrichment level for each day within the historical period is multiplied by its corresponding weight coefficient, summed, and then divided by the sum of all weight coefficients to obtain the normalized dew inertia index. The half-life is set to two days, meaning that the weight coefficient decays to half its value every two days backward.

[0055] In one embodiment, the historical period is taken as seven consecutive days. The weighting coefficients are 1.0 for day 0, approximately 0.707 for day 1, 0.5 for day 2, approximately 0.354 for day 3, 0.25 for day 4, approximately 0.177 for day 5, and 0.125 for day 6, with the sum of the weighting coefficients being approximately 3.043. If the dew enrichment level of the region within seven days is successively level 1, level 2, level 1, level 3, level 2, level 1, and level 0, then the normalized dew inertia index is equal to (1 multiplied by 1.0 plus 2 multiplied by 0.707 plus 1 multiplied by 0.5 plus 3 multiplied by 0.354 plus 2 multiplied by 0.25 plus 1 multiplied by 0.177 plus 0 multiplied by 0.125) divided by 3.043, with a calculated result of approximately 1.04, which is approximately 0.34 after normalization. This calculation method ensures that the recent dew state contributes more to the inertia index than the long-term state, consistent with the actual law that the degree of dew enrichment changes dynamically with meteorological conditions.

[0056] The calculation of the comprehensive irrigation demand is also related to the normalized dew inertia index. Specifically, the dew correction coefficient in the comprehensive irrigation demand formula is further multiplied by the dew inertia weight coefficient. The rules for determining the dew inertia weight coefficient are as follows: when the normalized dew inertia index is greater than or equal to 0.7, the weight coefficient of the current dew level increases from 0.5 to 0.8, and the adjustment range of the dew correction coefficient is increased by 20%; when the normalized dew inertia index is less than 0.3, the weight coefficient decreases to 0.3, and the adjustment range of the dew correction coefficient is reduced by 20%; when the normalized dew inertia index is between 0.3 and 0.7, the weight coefficient remains unchanged at 0.5. The weighting adjustment rule was determined through 30 consecutive days of dew monitoring in five experimental zones with different terrain conditions (low-lying areas, ventilation openings, flat land, elevated areas, and shaded areas). The normalized dew inertia index of the low-lying areas and shaded areas remained stable above 0.8, below 0.2 in the ventilation opening area, and around 0.5 in the flat land, thus verifying the adaptive effect of the weighting adjustment on the geographical characteristics of the zones. By using the spatiotemporal stability assessment of historical dew data, the confidence weight of the daily dew determination results was applied, avoiding the over-reliance on occasional high dew determinations in low-lying or poorly ventilated areas, and preventing the erroneous underestimation of irrigation amounts in occasional low dew determinations in well-ventilated areas, thus achieving an adaptive fusion of zone geographical characteristics and real-time perception.

[0057] After sequentially activating the micro-irrigation systems in the corresponding water supply zones, the method enters the irrigation effect feedback and threshold correction stage. The stable value of the substrate moisture content within a preset time period after irrigation stops is obtained. The determination method for the stable substrate moisture content is as follows: after irrigation stops, the substrate moisture content is continuously monitored. When the change in substrate moisture content within three consecutive sampling periods is less than one percent of the threshold, the arithmetic mean of that period is taken as the stable value. If the above stable condition is not met within sixty minutes after irrigation stops, the measured value at the sixtieth minute is directly taken as the stable value. The preset time period is typically thirty to sixty minutes to allow sufficient redistribution of substrate moisture.

[0058] In one embodiment, the sampling period is ten minutes, and the threshold of 1% corresponds to approximately 0.27% for a plastic hard drive and approximately 0.2% for a paper hard drive. This threshold is determined by testing the output stability of the substrate moisture content sensor during the natural decline phase after saturation infiltration. During the test, the moisture content decay rate drops below the threshold within ten minutes after infiltration is completed. The difference between the stable substrate moisture content value and the measured substrate moisture content value before irrigation is calculated to obtain the actual infiltration volume.

[0059] Based on the ratio of actual infiltration to theoretical water supply, the root development water requirement threshold for the next irrigation cycle is adjusted. The theoretical water supply is determined by the product of the micro-sprinkler's rated flow rate and the duration of a single water supply. When the ratio is lower than a preset lower infiltration limit, the root development water requirement threshold is increased. The theoretical water supply equals the sprinkler flow rate multiplied by the water supply duration. Actual infiltration is affected by the substrate pore structure and the degree of surface compaction, and is often lower than the theoretical value. The preset lower infiltration limit is set to 0.6%, meaning that when the actual infiltration is less than 60% of the theoretical water supply, it indicates uneven water distribution due to substrate compaction or sprinkler blockage, requiring an increase in the threshold to compensate for ineffective irrigation.

[0060] The correction range is as follows: when the ratio is between 0.5 and 0.6, the threshold is increased by 5%; when the ratio is between 0.4 and 0.5, the threshold is increased by 10%; when the ratio is below 0.4, the threshold is increased by 15%, simultaneously triggering a nozzle blockage check prompt. This lower infiltration limit and correction range were determined through a 21-day continuous irrigation infiltration test in a relatively heavy, viscous substrate. During the test, the actual infiltration volume was generally 40% to 50% of the theoretical value. After increasing the root development water requirement threshold of the plastic hard disk from 25% to 28%, the percentage of substrate moisture content that reached the expected target increased from 62% to 89%. Through closed-loop feedback between actual infiltration and theoretical water supply, the system dynamically identifies the decrease in infiltration efficiency caused by substrate compaction or nozzle blockage, and automatically adjusts the water requirement threshold for the next cycle to compensate. This avoids misjudging irrigation needs due to decreased infiltration efficiency, ensuring the stability of root water supply during long-term operation.

[0061] In one embodiment, when processing single-season rice seedlings in high-altitude areas, due to low air pressure and strong evaporation, although leaf dew is abundant, its evaporation rate is fast, and traditional irrigation strategies tend to underestimate the actual water demand. Under this condition, the ambient air pressure value of each water supply zone at the time of its first response to ambient light on the same day is obtained. The ambient air pressure value is obtained through an air pressure sensor integrated into a weather station. Based on the ambient air pressure value and the leaf dew enrichment level, the dew balance evaporation pressure difference is calculated, wherein the dew balance evaporation pressure difference is equal to (the difference between standard atmospheric pressure and ambient air pressure divided by standard atmospheric pressure) divided by the sum of the dew enrichment level and one. The standard atmospheric pressure is taken as 101.325 kPa.

[0062] Specifically, in this formula, the dew enrichment level plus one is used as the denominator. This ensures that the formula remains meaningful even at level zero dew (where the denominator is one, the pressure difference equals the relative deviation of air pressure, and the correction is the most conservative). It also reflects the buffering effect of dew thickness on evaporation resistance—the higher the level, the larger the denominator, the smaller the evaporation pressure difference, and the more conservative the correction for irrigation needs. The dew equilibrium evaporation pressure difference characterizes the energy potential difference required for leaf dew to evaporate from a saturated state to a gaseous state under current meteorological conditions. A larger pressure difference means faster dew evaporation and a weaker substitution effect for irrigation; therefore, the duration of a single watering session needs to be shortened to avoid oversaturation of leaf humidity. Based on the dew equilibrium evaporation pressure difference, the duration of a single watering session is corrected according to the following rules: When the dew balance evaporation pressure difference is less than or equal to 0.1, the duration of a single water supply remains unchanged; when the dew balance evaporation pressure difference is greater than 0.1 and less than or equal to 0.2, the duration of a single water supply is shortened by 10%; when the dew balance evaporation pressure difference is greater than 0.2 and less than or equal to 0.3, it is shortened by 20%; when the dew balance evaporation pressure difference is greater than 0.3, it is shortened by 25%, and the water supply interval is shortened by 10% accordingly. By shortening the interval, the duration of each water supply is compensated for, maintaining the daily cumulative water supply unchanged. This correction range was determined through comparative testing at three test sites at altitudes of 500 meters, 1000 meters, and 1500 meters for 15 consecutive days. During the test period, the ambient air pressure values ​​were approximately 95 kPa, 89 kPa, and 84 kPa, respectively, corresponding to dew balance evaporation pressure differences of 0.06, 0.11, and 0.17, respectively. The measured shortening range matched the above rules by more than 85%.

[0063] It should be noted that when the leaf dew enrichment level is zero, there is actually no dew covering the leaf surface. At this time, the dew balance evaporation pressure difference is equal to the relative air pressure deviation. The correction rule is directly applicable without additional branch processing, ensuring the continuity of the formula and the consistency of calculation across the entire level range.

[0064] The influence of air pressure on dew evaporation dynamics was assessed. In high-altitude, low-pressure environments, the problem of underestimating irrigation volume due to relying solely on dew enrichment levels was corrected. Long-term continuous irrigation was adjusted to a short-term, long-pulse mode, which not only met the enhanced root transpiration demand under low pressure, but also promoted root penetration and stress resistance training through pulsed water supply.

[0065] To verify the technical effectiveness of this method, a 60-day field comparison experiment was conducted at a rice seedling nursery. The experiment included three treatment groups: The first group uses the micro-sprinkler irrigation water supply control method described in this application (intelligent group), the second group uses fixed-cycle timed irrigation (control group 1, irrigates once every six hours, each time lasting fifteen minutes), and the third group uses single feedback irrigation based on the substrate moisture content threshold (control group 2, irrigation is triggered when the moisture content is below 20%, lasting twenty minutes).

[0066] The experimental seedling raising site was divided into eighteen water supply zones, each with an area of ​​approximately 100 square meters. Nine zones were covered with plastic hard disks, and nine zones were covered with paper hard disks, each planted with the same variety of early rice seedlings. During the experiment, the following indicators were recorded daily: substrate moisture content in each zone (automatically collected hourly using a time-domain reflectometry probe), leaf dew status (measured daily at 6:00 AM using a standard filter paper weighing method), disease incidence rate (investigated every five days for sheath blight and rice blast disease rates), seedling survival rate (statistics before transplanting), and total water consumption (cumulative from flow meters).

[0067] The experimental results showed that in the intelligent group, the irrigation trigger rate during the morning dew-rich period (6:00 to 8:00 AM) was only 12%, while it was 100% in control group 1 and 45% in control group 2. The intelligent group effectively avoided irrigation during high humidity periods by sensing dew. The average substrate moisture content of the plastic hard drive partitions in the intelligent group was maintained between 26.3% and 28.7%, and that of the paper hard drive partitions was maintained between 18.6% and 21.2%, both within their respective optimal ranges. In control group 1, the average moisture content of the plastic hard drive partitions was 22.1% (lower), and that of the paper hard drive partitions was 24.3% (higher). In control group 2, the average moisture content of the plastic hard drive partitions was 23.5%, and that of the paper hard drive partitions was 22.8%.

[0068] The incidence of rice sheath blight in the intelligent group was 3.2%, and the incidence of rice blast was 1.8%. In control group 1, the rates were 11.7% and 7.4%, respectively, and in control group 2, they were 8.3% and 4.9%, respectively. The seedling survival rate in the intelligent group was 94.6%, compared to 86.2% in control group 1 and 90.1% in control group 2. The total water consumption for the entire growth period in the intelligent group was 182 cubic meters per 100 cubic meters, compared to 247 cubic meters per 100 cubic meters in control group 1 and 216 cubic meters per 100 cubic meters in control group 2. These data indicate that this method is superior to the two control schemes in terms of disease control, seedling survival rate, and water-saving efficiency, and that the irrigation compatibility with different disk materials is good.

[0069] Through the close collaboration of the above steps, this method constructs a fully automated control system in a hard-ground hard disk seedling raising environment, encompassing leaf microenvironment sensing, root water stress diagnosis, irrigation demand quantification, prioritization, and dynamic parameter correction. This not only improves the accuracy and water resource utilization efficiency of micro-sprinkler irrigation but also avoids the high incidence of diseases caused by neglecting leaf humidity in traditional irrigation through real-time feedback of dew status, providing technical support for the standardized and intelligent management of rice seedling raising.

[0070] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A micro-sprinkler irrigation water supply control method for rice seedling raising on hard ground, wherein the seedling raising site is pre-divided into several water supply zones, each water supply zone is equipped with a light sensor and a substrate moisture content sensor, and seedling raising hard disks are laid in each water supply zone, characterized in that, include: The rising edge time-domain parameters of the output signal of each of the light sensors when they first respond to ambient light on the same day are obtained. The rising edge time-domain parameters include response delay time and rising slope. Based on the rising edge time domain parameters, the leaf dew enrichment level of each water supply zone is determined, wherein the greater the response delay time and the smaller the rising slope, the higher the leaf dew enrichment level. Obtain the measured values ​​of substrate moisture content in each water supply zone, and determine the stress marking status of each water supply zone based on the comparison results between the measured values ​​of substrate moisture content and the preset root development water requirement threshold. The root development water requirement threshold is determined according to the type of seedling hard disk substrate. Based on the leaf dew enrichment level and the stress marker status, the comprehensive irrigation demand of each water supply zone is calculated. The higher the leaf dew enrichment level, the lower the comprehensive irrigation demand. When the stress marker status is stress, the comprehensive irrigation demand is increased. The increase is positively correlated with the difference between the root development water requirement threshold and the measured value of the substrate moisture content. Arrange the water supply priority of each water supply zone in descending order of the comprehensive irrigation demand; According to the water supply priority, the micro-sprinkler irrigation of the corresponding water supply zones is turned on in sequence. The water supply zone with a large overall irrigation demand is configured with a longer single water supply duration and a shorter water supply interval than the water supply zone with a small overall irrigation demand.

2. The method according to claim 1, characterized in that, The step of determining the leaf dew enrichment level of each water supply zone based on the rising edge time domain parameters includes: Calculate the delay ratio between the response delay time and the preset baseline delay time; Calculate the slope ratio between the rising slope and the preset reference slope; The leaf dew enrichment level is determined based on the weighted composite index of the delay ratio and the slope ratio.

3. The method according to claim 1, characterized in that, Also includes: Obtain the duration of the dark state of each water supply zone before the first response to ambient light on the same day; The threshold for determining the leaf surface dew accumulation level is adjusted based on the duration of the dark state. The longer the duration of the dark state, the more lenient the adjusted threshold will be, so as to avoid over-judgment of dew due to low temperatures during long nights.

4. The method according to claim 1, characterized in that, The substrate types for seedling raising hard disks include plastic hard disks and paper hard disks, with the root development water requirement threshold of the plastic hard disks being higher than that of the paper hard disks.

5. The method according to claim 1, characterized in that, After sequentially activating the micro-irrigation systems corresponding to the water supply zones, the process further includes: Obtain the stable value of substrate moisture content within a preset time after irrigation stops; The difference between the stable value of the substrate moisture content and the measured value of the substrate moisture content before irrigation is calculated to obtain the actual infiltration water volume; Based on the ratio of the actual infiltration volume to the theoretical water supply, the root development water requirement threshold for the next irrigation cycle is adjusted. The theoretical water supply is determined by the product of the rated flow rate of the micro-sprinkler and the duration of a single water supply. When the ratio is lower than the preset infiltration lower limit, the root development water requirement threshold is increased.

6. The method according to claim 1, characterized in that, When there are multiple water supply zones with the same comprehensive irrigation demand, the method further includes: Obtain the ambient temperature of each water supply zone with the same demand when it first responds to ambient light on the same day; The order in which water supply zones with the same demand are opened is determined based on the ambient temperature, wherein the water supply zones with lower ambient temperatures are opened earlier.

7. The method according to claim 1, characterized in that, The rising edge time-domain parameter also includes a frequency-domain attenuation parameter, which is obtained by extracting the high-frequency energy ratio after the output signal is subjected to a short-time Fourier transform. The greater the response delay time, the smaller the rise slope, and the lower the proportion of high-frequency energy, the higher the leaf dew enrichment level.

8. The method according to claim 1, characterized in that, Also includes: Obtain the leaf dew enrichment level sequence of each water supply zone within a preset historical period, and calculate the dew inertia index of each water supply zone. The dew inertia index characterizes the spatiotemporal stability of the dew enrichment degree of the corresponding water supply zone. The calculation of the comprehensive irrigation demand is also related to the dew inertia index. The larger the dew inertia index, the more significant the weight of the current leaf dew enrichment level on the comprehensive irrigation demand.

9. The method according to claim 1, characterized in that, The duration of a single water supply is determined based on the ratio of the comprehensive irrigation demand to the preset unit demand water volume. The water supply interval is determined based on the combined relationship between the comprehensive irrigation demand and the cumulative sunshine duration of the day, wherein the longer the cumulative sunshine duration of the day, the shorter the water supply interval.

10. The method according to claim 1, characterized in that, Also includes: Obtain the ambient air pressure value of each water supply zone at the first response to ambient light on the same day; Based on the ambient air pressure value and the leaf dew enrichment level, the dew balance evaporation pressure difference is calculated. The dew balance evaporation pressure difference is equal to the difference between the standard atmospheric pressure and the ambient air pressure value divided by the standard atmospheric pressure, and then divided by the sum of the dew enrichment level and one. The lower the ambient air pressure value, the larger the dew balance evaporation pressure difference; the higher the leaf dew enrichment level, the smaller the dew balance evaporation pressure difference. The duration of a single water supply is adjusted based on the dew balance evaporation pressure difference. The larger the dew balance evaporation pressure difference, the shorter the adjusted duration of a single water supply, in order to avoid oversaturation of leaf surface humidity under low air pressure conditions.

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