Real-time growth monitoring and cultivation control system for potato cultivation in saline-alkali land

Abstract

This application provides a real-time monitoring and cultivation regulation system for potato cultivation in saline-alkali land, belonging to the field of seed and seedling cultivation technology. The system includes: a cultivation monitoring module that monitors soil parameters in the potato root zone, spectral reflectance characteristics of the potato canopy, and leaf thermal infrared images; a stress signal generation module that determines a composite stress signal characterizing the synergistic effect of osmotic stress and ion toxicity on the potato based on canopy spectral reflectance characteristics and leaf thermal infrared images; a root zone leaching module that initiates intermittent leaching of the potato root zone with slightly saline water and records the leaching duration; and a nutrient solution delivery module that determines the nutrient solution injection ratio and injection duration based on the leaching duration and the lowest photochemical vegetation index during the composite stress signal generation process, and delivers the nutrient solution to the potato root zone. The technical solution provided in this application can achieve leaching and nutrient regulation of the potato root zone under the spatiotemporally asynchronous synergistic damage caused by osmotic stress and ion toxicity.

Description

Technical Field

[0001] This application relates to the field of seed and seedling cultivation technology, and more specifically, to a real-time growth monitoring and cultivation control system for potato cultivation in saline-alkali land. Background Technology

[0002] Seed and seedling cultivation is the primary link in improving the quality and efficiency of the potato industry in saline-alkali land. It has evolved from traditional experience-based judgment to precision and intelligence. my country has a vast area of ​​saline-alkali land available for use, but potatoes, as a salt-alkali sensitive crop, are easily inhibited by high salinity and alkalinity. This requires the cultivation process to have stronger stress resistance capabilities. Traditional cultivation techniques focus on screening varieties for alkali tolerance and improving the substrate, such as using tissue culture seedlings to identify alkali-tolerant germplasm or applying salt-alkali amendments in the seedbed to regulate the microenvironment. Currently, the technology system further integrates real-time monitoring and intelligent control methods. Field monitoring equipment dynamically detects key indicators such as soil pH and electrical conductivity (EC value), and combined with an intelligent integrated water and fertilizer system, it precisely regulates water and fertilizer supply based on soil moisture data, realizing the transformation from experience-based farming to data-driven farming, and providing scientific guarantees for the robust growth of potatoes in saline-alkali land.

[0003] In existing potato cultivation in saline-alkali land, on the one hand, the degree of saline-alkali stress is quantified by monitoring key indicators such as soil electrical conductivity (EC value) and pH value. On the other hand, non-destructive testing technologies such as hyperspectral analysis are used to diagnose nutrient deficiencies or physiological states by capturing changes in the spectral characteristics of crop leaves. At the regulatory level, following the principle of "combining soil improvement with growth promotion," soil conditioners are applied to reduce the salt and alkali concentration around the roots, or precise drip irrigation using integrated water and fertilizer systems is used to leach salts, helping the plant maintain normal osmotic regulation and ion balance in a saline-alkali environment. Traditional monitoring systems usually treat osmotic stress caused by excessive soil salinity and ion toxicity caused by excessive absorption of sodium and chloride ions as a synchronous process, ignoring the spatiotemporally asynchronous synergistic damage of osmotic stress and ion toxicity. However, in the potato root zone microenvironment, osmotic stress is mainly dominated by soil water potential. Ion toxicity can occur rapidly and be partially alleviated under irrigation or transpiration, exhibiting high temporal variability. Ion toxicity, on the other hand, depends on the root system's net absorption and differentiation capacity for specific ions, is cumulative, and has a certain lag. When using a fixed soil conductivity threshold to trigger regulation, it often only captures the superficial manifestation of total salt stress, failing to distinguish whether crop damage is primarily due to water deficit-type osmotic stress or the accumulation of sodium / chloride ions in leaves to toxic concentrations. This leads to a nonlinear time lag between the decrease in photochemical vegetation index and the increase in soil conductivity, causing frequent misjudgments by single-point-of-time and single-index decision models. Consequently, the timing of leaching and nutrient regulation in the potato root zone is inaccurate, exacerbating root damage and nutrient imbalance. Therefore, how to achieve leaching and nutrient regulation in the potato root zone under the spatiotemporally asynchronous synergistic damage of osmotic stress and ion toxicity has become a challenge for the industry. Summary of the Invention

[0004] This application provides a real-time growth monitoring and cultivation regulation system for potato cultivation in saline-alkali land, which can achieve leaching and nutrient regulation of the potato root zone under the spatiotemporal asynchronous synergistic damage of osmotic stress and ion toxicity.

[0005] This application provides a real-time growth monitoring and cultivation control system for potato cultivation in saline-alkali land, the system comprising:

[0006] The cultivation monitoring module is used to monitor soil parameters at the same depth in the root zone of potatoes in saline-alkali land, as well as the spectral reflectance characteristics of the potato canopy and thermal infrared images of leaves.

[0007] The stress signal generation module is used to determine a composite stress signal that characterizes the synergistic effect of osmotic stress and ion toxicity on potatoes based on the canopy spectral reflectance characteristics and the leaf thermal infrared image when the soil parameters are higher than the corresponding preset soil threshold.

[0008] The root zone leaching module is used to respond to the composite stress signal, take the soil matrix potential corresponding to the time when the composite stress signal is generated as the starting matrix potential, start the intermittent leaching operation of slightly saline water in the potato root zone, and terminate the intermittent leaching operation of slightly saline water and record the leaching duration when the cultivation monitoring module detects that the soil conductivity has fallen back to the preset safe conductivity range.

[0009] The nutrient solution delivery module is used to determine the injection ratio and injection duration of calcium- and potassium-containing nutrient solutions based on the leaching duration and the lowest photochemical vegetation index during the generation process of the composite stress signal, and then deliver the calcium- and potassium-containing nutrient solutions to the potato root zone.

[0010] Furthermore, the cultivation monitoring module monitors soil parameters at the same depth in the potato root zone of saline-alkali land, as well as the spectral reflectance characteristics of the potato canopy and leaf thermal infrared images:

[0011] Multi-source sensor probes were deployed at the same depth in the potato root zone to collect soil electrical conductivity and soil matrix potential, and the air temperature of the potato canopy was obtained to generate soil parameters at the same depth in the potato root zone of saline-alkali land.

[0012] Using a multispectral imager mounted on a mobile platform, within the same time window for acquiring the soil parameters, the spectral reflectance characteristics of the potato canopy in the visible to near-infrared bands and the thermal infrared images of the potato canopy leaves were acquired.

[0013] Furthermore, in the stress signal generation module, when the soil parameters are higher than the corresponding preset soil threshold, the composite stress signal characterizing the synergistic effect of osmotic stress and ion toxicity on potatoes is determined based on the canopy spectral reflectance characteristics combined with the leaf thermal infrared image. Specifically, this includes:

[0014] The soil electrical conductivity and soil matrix potential in the soil parameters are obtained and compared with the corresponding preset soil thresholds. The preset soil thresholds include a preset matrix potential threshold and a preset electrical conductivity threshold. When the soil matrix potential is lower than the preset matrix potential threshold and the soil electrical conductivity is higher than the preset electrical conductivity threshold, a primary saline-alkali stress signal is generated.

[0015] Under the condition of generating the primary salt-alkali stress signal, the photochemical vegetation index is determined based on the canopy spectral reflectance characteristics, and the canopy temperature difference is obtained based on the difference between the average canopy temperature of the preset leaf area in the leaf thermal infrared image and the air temperature of the potato canopy.

[0016] During the period when the photochemical vegetation index is lower than a preset vegetation index threshold and the canopy temperature difference exceeds a preset temperature difference threshold, a composite stress signal characterizing the synergistic effect of osmotic stress and ion toxicity on potatoes is generated.

[0017] Furthermore, in the stress signal generation module, during the period when the photochemical vegetation index is lower than a preset vegetation index threshold and the canopy-temperature difference exceeds a preset temperature difference threshold, the generation of a composite stress signal characterizing the synergistic effect of osmotic stress and ion toxicity on potatoes specifically includes:

[0018] Within a continuous time window, when it is determined that the crown temperature difference exceeds a preset temperature difference threshold and the photochemical vegetation index is continuously lower than a preset vegetation index threshold, it is confirmed as a period of combined stress for potatoes, where stomatal closure temperature rise dominated by osmotic stress and photosynthetic pigment degradation dominated by ion toxicity.

[0019] The crown temperature difference and photochemical vegetation index during the combined stress period were normalized and weighted to generate a combined stress signal.

[0020] Furthermore, in the root zone leaching module, in response to the composite stress signal, the soil matrix potential corresponding to the time the composite stress signal is generated is used as the starting matrix potential to initiate the intermittent leaching operation of slightly saline water on the potato root zone. This specifically includes:

[0021] Receive the composite stress signal and use the root zone soil matrix potential corresponding to the time when the composite stress signal is generated as the starting matrix potential;

[0022] The initial rinsing intensity is determined by comparing the starting matrix potential with the corresponding threshold in the preset matrix potential-rinsing intensity function.

[0023] According to the initial leaching intensity, slightly saline water with a preset mineralization degree is injected into the potato root zone in a pulse manner. After each injection pulse, the injection is paused, and the salinity rebalancing state of the root zone is determined by the real-time change rate of the soil conductivity.

[0024] When the soil conductivity monitored under the salinity rebalancing state is higher than the upper limit of the preset safe conductivity range, brackish water is pulsed again at the initial leaching intensity to form an intermittent leaching cycle.

[0025] Furthermore, in the root zone leaching module, when the cultivation monitoring module detects that the soil conductivity has fallen back to a preset safe conductivity range, the intermittent leaching operation with brackish water is terminated and the leaching duration is recorded. Specifically, this includes:

[0026] During the intermittent leaching cycle, the soil conductivity in the root zone was continuously monitored, and the soil conductivity after each pulse injection and salt rebalancing was compared with the preset safe conductivity range.

[0027] When it is determined that the soil electrical conductivity after the salinity rebalancing has fallen back to the preset safe electrical conductivity range, the brackish water injection channel is closed and the intermittent rinsing cycle is terminated.

[0028] Extract the time difference from the moment corresponding to the start of the matrix potential to the moment when the brackish water injection channel is closed, and record it as the rinsing duration.

[0029] Furthermore, in the cultivation monitoring module, the multi-source sensing probe includes a conductivity sensor and a tensiometer-type matrix potential sensor.

[0030] Furthermore, in the nutrient solution delivery module, determining the injection ratio and injection duration of the calcium- and potassium-containing nutrient solutions based on the leaching duration and the lowest photochemical vegetation index during the generation of the composite stress signal specifically includes:

[0031] The lowest photochemical vegetation index recorded during the generation of the composite stress signal was obtained, and the leaching duration recorded by the root zone leaching module was extracted.

[0032] Substitute the rinsing duration into the pre-constructed rinsing ion loss function to calculate the estimated loss of effective potassium ions and effective calcium ions in the root zone.

[0033] Based on the estimated loss and the minimum photochemical vegetation index, the potassium-calcium molar ratio is inverted through a preset stress recovery nutrient ratio model, and this potassium-calcium molar ratio is used as the injection ratio of calcium-containing and potassium-containing nutrient solutions.

[0034] Using the rinsing duration as a baseline variable, and considering the deviation of the minimum photochemical vegetation index from the preset optimal vegetation index, the injection duration is calculated using a recovery duration function.

[0035] Furthermore, in the nutrient solution delivery module, delivering the calcium- and potassium-containing nutrient solution to the potato root zone specifically includes:

[0036] According to the injection ratio, the intake volumes of calcium nitrate mother liquor and potassium nitrate mother liquor of preset concentrations are respectively measured, mixed in the nutrient solution mixing chamber and diluted with irrigation water to the target working concentration to obtain calcium-containing and potassium-containing nutrient solutions.

[0037] After the brackish water injection channel is closed, the nutrient solution delivery channel is switched, and the calcium- and potassium-containing nutrient solutions are delivered to the potato root zone at a preset low-pressure drip irrigation rate for the duration of injection.

[0038] Furthermore, in the cultivation monitoring module, uncooled focal plane array thermal infrared cameras are used to acquire leaf thermal infrared images of the potato canopy.

[0039] The technical solutions provided by the embodiments disclosed in this application have the following beneficial effects:

[0040] The real-time monitoring and cultivation regulation system for potato cultivation in saline-alkali land provided in this application can achieve leaching and nutrient regulation in the potato root zone under the spatiotemporally asynchronous synergistic damage of osmotic stress and ion toxicity. Firstly, the cultivation monitoring module achieves three-dimensional real-time acquisition of soil physicochemical state and canopy physiological phenotype information in the potato root zone through spatiotemporal synchronous acquisition of multi-source sensing probes and multispectral and thermal infrared imaging, providing a multi-dimensional synchronous data foundation for subsequent stress identification and regulation decisions. Secondly, the stress signal generation module generates primary saline-alkali stress signals through dual threshold screening of soil conductivity and matrix potential, and then... The temporal synergistic determination of photosynthetic chemovegetation index and canopy temperature difference generates a composite stress confirmation signal. This simultaneously identifies stomatal closure-induced warming caused by osmotic stress and photosynthetic pigment degradation caused by ion toxicity within the same time window, achieving a shift from single-index threshold alarms to quantitative identification of synergistic stresses. This significantly improves the accuracy and specificity of salt-alkali stress type identification. Then, the root zone leaching module is triggered by the composite stress confirmation signal, locking the soil matrix potential at the stress moment as the starting benchmark. The leaching flux is adaptively matched through a matrix potential-leaching intensity function, and micro-leaching is executed in an intermittent cyclical manner combining pulse injection with salt reequilibrium state determination. The process involves saline leaching, which automatically terminates when the soil electrical conductivity returns to a safe range, and the leaching duration is recorded. This achieves precise closed-loop control of salt and desalination, adapting leaching intensity to soil drought and synchronizing leaching intervals with salt dissolution and redistribution kinetics. This effectively removes salt from the root zone while avoiding deep seepage and excessive nutrient loss caused by traditional flood irrigation. Finally, the nutrient solution delivery module uses the leaching duration and the minimum photochemical vegetation index to derive the potassium-calcium molar ratio using a leaching ion loss function and a stress recovery nutrient ratio model. The injection ratio is then adaptively calculated based on the stress severity using a recovery duration function, and finally, the solution is delivered according to this ratio. By precisely replenishing the root zone with calcium and potassium-containing nutrient solutions over a specific time period, quantitative compensation for nutrient deficiencies in the root zone after leaching and desalination and targeted promotion of photosynthetic function recovery are achieved. This enables the system to form a closed-loop linkage from stress perception to regulation execution and then to nutrient recovery, avoiding misjudgments caused by decision-making models based on single time points and single indicators, which can lead to inaccurate timing of leaching and nutrient regulation in the potato root zone. This ensures the growth recovery capacity and yield stability of potatoes in saline-alkali land under combined stress conditions. In summary, the technical solution provided in this application can achieve leaching and nutrient regulation in the potato root zone under the spatiotemporally asynchronous synergistic damage of osmotic stress and ion toxicity. Attached Figure Description

[0041] Figure 1 This is a modular structure diagram of a real-time growth monitoring and cultivation regulation system for potato cultivation in saline-alkali land, as shown in some embodiments of this application.

[0042] Figure 2This is a schematic diagram of the potato root zone and potato canopy during the potato cultivation process in saline-alkali land, as shown in this embodiment of the present application.

[0043] Figure 3 This is an exemplary flowchart illustrating the determination of a composite stress signal according to some embodiments of this application. Detailed Implementation

[0044] To better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] refer to Figure 1 As shown in the figure, this is a modular structure diagram of a real-time growth monitoring and cultivation regulation system for potato cultivation in saline-alkali land according to this embodiment of the present application. The system includes: a cultivation monitoring module 100, a stress signal generation module 200, a root zone rinsing module 300, and a nutrient solution delivery module 400, which are described below:

[0046] The cultivation monitoring module 100 is used to monitor soil parameters at the same depth in the root zone of potatoes in saline-alkali land, as well as the spectral reflectance characteristics of the potato canopy and thermal infrared images of the leaves.

[0047] refer to Figure 2 This figure is a schematic diagram of the potato root zone and potato canopy during the potato cultivation process in saline-alkali land according to this embodiment of the application. The figure includes potato seedling cultivation, potato root zone, and potato canopy. The potato root zone refers to the root-soil-microorganism interaction microdomain centered on the taproot and stolons, extending radially for about 15-20 cm and concentrated in the 0-40 cm soil layer. This area is the core interface for water and nutrient absorption, and its salinity and water dynamics directly determine the intensity of osmotic stress and ion toxicity. The potato canopy refers to the collective cover layer formed by the above-ground parts of the potato plant, such as stems, leaves, flowers, and fruits, arranged in a certain geometric structure in the space above the ground. It is an integrated observation object characterizing the above-ground growth status, photosynthetic physiological activity, and stress response characteristics of the potato.

[0048] In the cultivation monitoring module, the monitoring of soil parameters at the same depth in the potato root zone of saline-alkali land, the spectral reflectance characteristics of the potato canopy, and leaf thermal infrared images are achieved through the following steps:

[0049] Multi-source sensor probes were deployed at the same depth in the potato root zone to collect soil electrical conductivity and soil matrix potential, and the air temperature of the potato canopy was obtained to generate soil parameters at the same depth in the potato root zone of saline-alkali land.

[0050] Using a multispectral imager mounted on a mobile platform, within the same time window for acquiring the soil parameters, the spectral reflectance characteristics of the potato canopy in the visible to near-infrared bands and the thermal infrared images of the potato canopy leaves were acquired.

[0051] In practice, firstly, multi-source sensor probes are horizontally inserted at the same depth in the potato root zone to collect soil conductivity and soil matrix potential. A temperature sensor is used to obtain the air temperature of the potato canopy, generating soil parameters at the same depth in the potato root zone of saline-alkali land. The multi-source sensor probes include conductivity sensors and tensiometer-type matrix potential sensors. The "same depth" is determined based on the distribution layer of the main potato root system and is 15 to 20 centimeters from the soil surface; details are omitted here. The soil parameters refer to a multidimensional dataset used to quantitatively characterize the physical and chemical states of the root zone soil, synchronously collected and generated by the multi-source sensor probes deployed at the same depth in the soil layer. Then, within the same time window, a multispectral imager mounted on a motorized, movable platform is used to scan and image the potato canopy from a top-down angle. This multispectral imager incorporates a beam splitter prism and a narrowband filter array. Canopy reflectance radiance was collected at wavelengths of 531 nm, 570 nm, 670 nm, and 780 nm, respectively. The spectral reflectance of each band was obtained by combining the reflectance radiance of the diffuse reflectance standard reference plate with the reflectance calculation formula, thereby generating spectral reflectance characteristics in the visible to near-infrared bands. The spectral reflectance characteristics refer to the solar radiation reflectance characteristics that reflect the pigment content and cell structure of the canopy leaves. Simultaneously, uncooled focal plane array thermal infrared cameras were used to collect thermal infrared images of potato canopy leaves. That is, uncooled focal plane array thermal infrared cameras integrated on the same movable platform were used to collect thermal infrared images of potato canopy leaves. The working wavelength of this thermal infrared camera is 8 to 14 micrometers. After the raw thermal infrared images were corrected by non-uniformity correction algorithm and emissivity parameter, the thermal infrared images of leaves corresponding to the canopy surface brightness temperature value of each pixel were output, completing the spatiotemporal synchronous acquisition of multi-source remote sensing data.

[0052] It should be noted that the leaf thermal infrared image in this application refers to the spatial temperature distribution image reflecting the transpiration cooling effect under the opening and closing state of leaf stomata. In this embodiment, by capturing the radiation energy emitted by potato canopy leaves in the thermal infrared band and correcting the emissivity, the spatial distribution of canopy surface brightness temperature is obtained, which can reflect the difference in transpiration cooling effect under the opening and closing state of leaf stomata. Under saline-alkali stress, root osmotic stress leads to the closure of leaf stomata and a decrease in transpiration rate, and the leaf temperature rises accordingly. The spatial distribution pattern and temperature rise of the canopy temperature provide a direct basis for determining the physiological state of plant water. The difference between the canopy temperature and the root zone air temperature is the canopy temperature difference, which can be used to identify physiological response characteristics dominated by osmotic stress.

[0053] The stress signal generation module 200 is used to determine, based on the canopy spectral reflectance characteristics and the leaf thermal infrared image, a composite stress signal characterizing the synergistic effect of osmotic stress and ion toxicity on potatoes when the soil parameters are higher than the corresponding preset soil threshold.

[0054] In some embodiments, reference Figure 3 As shown in the figure, this is an exemplary flowchart illustrating the determination of a combined stress signal according to some embodiments of this application. In the stress signal generation module, when the soil parameters are higher than the corresponding preset soil threshold, the determination of the combined stress signal characterizing the synergistic effect of osmotic stress and ion toxicity on potatoes based on the canopy spectral reflectance characteristics combined with the leaf thermal infrared image is achieved through the following steps:

[0055] In step 2001, the soil electrical conductivity and soil matrix potential in the soil parameters are obtained and compared with the corresponding preset soil thresholds. The preset soil thresholds include a preset matrix potential threshold and a preset electrical conductivity threshold. When the soil matrix potential is lower than the preset matrix potential threshold and the soil electrical conductivity is higher than the preset electrical conductivity threshold, a primary saline-alkali stress signal is generated.

[0056] In step 2002, under the condition of generating the primary salt-alkali stress signal, the photochemical vegetation index is determined based on the canopy spectral reflectance characteristics, and the canopy temperature difference is obtained based on the difference between the average canopy temperature of the preset leaf area in the leaf thermal infrared image and the air temperature of the potato canopy.

[0057] In step 2003, during the period when the photochemical vegetation index is lower than a preset vegetation index threshold and the crown temperature difference exceeds a preset temperature difference threshold, a composite stress signal characterizing the synergistic effect of osmotic stress and ion toxicity on potatoes is generated.

[0058] In specific implementation, firstly, the soil electrical conductivity and soil matrix potential are acquired from the soil parameters and compared with the corresponding preset soil thresholds. The preset soil thresholds include a preset matrix potential threshold and a preset electrical conductivity threshold. The soil electrical conductivity and soil matrix potential are compared in real time with the preset matrix potential threshold and preset electrical conductivity threshold stored in the threshold register through a comparator circuit. The preset matrix potential threshold can be set to -40 kPa and the preset electrical conductivity threshold can be set to 4 dS / m, which is not limited here. When the soil matrix potential is higher than -40 kPa and the soil electrical conductivity is higher than 4 dS / m, a primary salt-alkali stress signal is output by a logic AND gate circuit. The primary salt-alkali stress signal is a primary alarm signal indicating that the soil physicochemical state has entered the salt-alkali stress judgment interval that may trigger a physiological response in plants. Then, when the primary salt-alkali stress signal is valid, the reflectance data at wavelengths of 531 nm and 570 nm collected by the multispectral imager are called and input into the photochemical vegetation index calculation formula. The photochemical vegetation index was obtained, among which, Photochemical vegetation index, The reflectance at a wavelength of 531 nm in the canopy spectral reflectance characteristics. The reflectance at a wavelength of 570 nm in the canopy spectral reflectance characteristics is used. The photochemical vegetation index refers to the light energy utilization efficiency index that reflects the conversion state of zeaxanthin to maize xanthin in the leaf xanthophyll cycle. The leaf thermal infrared image is divided into a preset leaf area by the Otsu's method. The preset leaf area is the area where the potato leaves are located. The arithmetic mean of the brightness temperature values ​​of all pixels in the preset leaf area is calculated as the canopy average temperature. The difference between the canopy average temperature and the air temperature of the potato canopy recorded in the soil parameters within the same time window is used to obtain the canopy temperature difference. The canopy temperature difference is a temperature difference parameter that reflects the strength of the leaf transpiration cooling effect. Finally, during the period when the photochemical vegetation index is lower than the preset vegetation index threshold and the canopy temperature difference exceeds the preset temperature difference threshold, a composite stress signal characterizing the synergistic effect of osmotic stress and ion toxicity on potatoes is generated.

[0059] Specifically, during the period when the photochemical vegetation index is lower than a preset vegetation index threshold and the canopy temperature difference exceeds a preset temperature difference threshold, the generation of a composite stress signal characterizing the synergistic effect of osmotic stress and ion toxicity on potatoes is achieved through the following steps:

[0060] Within a continuous time window, when it is determined that the crown temperature difference exceeds a preset temperature difference threshold and the photochemical vegetation index is continuously lower than a preset vegetation index threshold, it is confirmed as a period of combined stress for potatoes, where stomatal closure temperature rise dominated by osmotic stress and photosynthetic pigment degradation dominated by ion toxicity.

[0061] The crown temperature difference and photochemical vegetation index during the combined stress period were normalized and weighted to generate a combined stress signal.

[0062] In specific implementation, firstly, a dual-condition compliance judgment logic unit performs time-series analysis on the comparison results of consecutive sampling times using a sliding time window. The width of this sliding time window is set to 30 minutes, and the step size is 5 minutes. When the canopy temperature difference at each sampling point within the judgment window continuously exceeds a preset temperature difference threshold and the photochemical vegetation index continuously falls below a preset vegetation index threshold, the time period corresponding to this sliding time window is identified as a composite stress period. The composite stress period is the time segment in which potatoes simultaneously exhibit a synergistic stress state of stomatal closure temperature rise dominated by osmotic stress and photosynthetic pigment degradation dominated by ion toxicity. Then, all canopy temperature difference values ​​and photochemical vegetation indexes recorded within the composite stress period are extracted. The normalized canopy temperature difference and the normalized photochemical vegetation index are obtained by mapping the canopy temperature difference to the 0-1 range and the photochemical vegetation index to the 0-1 range, respectively, using the deviation normalization method. Then, based on the preset osmotic stress weighting coefficient of 0.6 and ion toxicity weighting coefficient of 0.4, the product of the normalized canopy temperature difference multiplied by 0.6 and the product of the difference between 1 and the normalized photochemical vegetation index multiplied by 0.4 are added to calculate the composite stress index. The composite stress index refers to the synergistic stress intensity parameter that quantifies the degree of osmotic stress and the degree of ion toxicity, and its value ranges from 0 to 1. The signal encoding unit packages the composite stress index with the start and end timestamps of the composite stress period to generate a composite stress signal.

[0063] It should be noted that the composite stress signal in this application refers to a composite stress state signal that confirms the synergistic effect of osmotic stress and ion toxicity on potatoes and carries quantitative information about the stress. Compared with the prior art, the composite stress signal in this scheme does not use a single indicator of soil salinity or a single remote sensing parameter of canopy temperature as the basis for stress judgment. Instead, after generating the primary salinity stress signal, a synergistic judgment mechanism of photochemical vegetation index and canopy temperature difference is introduced. Through the dual-parameter temporal conformity judgment that the canopy temperature difference continuously exceeds the preset temperature difference threshold and the photochemical vegetation index continuously falls below the preset vegetation index threshold within a sliding time window, the stomatal closure warming effect caused by osmotic stress and the photosynthetic pigment degradation effect caused by ion toxicity are simultaneously confirmed in the time dimension. Furthermore, the two are normalized and weighted and fused to generate a composite stress confirmation signal that carries quantitative information about the degree of osmotic stress and the degree of ion toxicity. This enables accurate identification and quantitative characterization of the synergistic occurrence of osmotic stress and ion toxicity rather than a single stress type.

[0064] The root zone leaching module 300 is used to respond to the composite stress signal, take the soil matrix potential corresponding to the time when the composite stress signal is generated as the starting matrix potential, start the intermittent leaching operation of slightly saline water on the potato root zone, and terminate the intermittent leaching operation of slightly saline water and record the leaching duration when the cultivation monitoring module detects that the soil conductivity has fallen back to the preset safe conductivity range.

[0065] In the root zone leaching module, in response to the composite stress signal, the soil matrix potential corresponding to the time the composite stress signal is generated is used as the starting matrix potential to initiate the intermittent leaching operation of slightly saline water on the potato root zone, which is achieved through the following steps:

[0066] Receive the composite stress signal and use the root zone soil matrix potential corresponding to the time when the composite stress signal is generated as the starting matrix potential;

[0067] The initial rinsing intensity is determined by comparing the starting matrix potential with the corresponding threshold in the preset matrix potential-rinsing intensity function.

[0068] According to the initial leaching intensity, slightly saline water with a preset mineralization degree is injected into the potato root zone in a pulse manner. After each injection pulse, the injection is paused, and the salinity rebalancing state of the root zone is determined by the real-time change rate of the soil conductivity.

[0069] When the soil conductivity monitored under the salinity rebalancing state is higher than the upper limit of the preset safe conductivity range, brackish water is pulsed again at the initial leaching intensity to form an intermittent leaching cycle.

[0070] It should be noted that, in this application, brackish water refers to water resources with a mineralization of 2 g / L to 5 g / L. The osmotic potential of brackish water is relatively close to that of the soil solution in the root zone of saline-alkali land. During the leaching process, the osmotic stress is gradually reduced, avoiding osmotic shock damage to the potato roots caused by drastic fluctuations in water potential. At the same time, the calcium and magnesium ions naturally contained in the brackish water displace the exchangeable sodium ions adsorbed on the soil colloids and move them down to below the root zone by gravity, achieving rapid desalination and alkali reduction in the root zone. In this process, the soil aggregate structure and porosity are maintained, preventing soil compaction and ensuring that a stable moist channel is retained in the root zone after leaching. This provides a fluid transport path for the subsequent precision nutrient solution supply module to accurately deliver calcium and potassium nutrient solutions to the potato root zone along this channel.

[0071] In specific implementation, firstly, the signal receiving and parameter locking unit receives the composite stress confirmation signal, parses the start timestamp of the composite stress period from the composite stress confirmation signal, and retrieves the soil matrix potential at the corresponding time from the synchronously stored soil parameters based on the start timestamp. This soil matrix potential is locked and recorded as the starting matrix potential, which refers to the baseline parameter of the root zone soil moisture and energy state that triggers the intermittent leaching operation with brackish water. Next, the starting matrix potential is input into a preset matrix potential-leaching intensity function for interpolation to determine the initial leaching intensity. The initial leaching intensity refers to the volumetric flow rate of brackish water injected per unit length of root row per unit time. The matrix potential-leaching intensity function is a piecewise linear mapping relationship based on the moisture characteristic curve of loamy saline-alkali soil. The expression of the matrix potential-leaching intensity function is as follows:

[0072]

[0073] in, The input is the initiation matrix potential; The matrix potential corresponding to field water holding capacity is taken as -33 kPa; The matrix potential at the first inflection point is set to -50 kPa. The matrix potential at the second inflection point is -80 kPa; |、| |、| |、| | represents the absolute value of the matrix potential mentioned above; I represents the initial rinsing intensity output. The minimum rinsing intensity is set at 2 L / (m·h); For medium rinsing intensity, the value is 4 L / (m·h); The maximum leaching intensity is set to 6 L / (m·h). The principle behind this expression is that the absolute value of the initiating matrix potential directly reflects the severity of soil moisture deficit in the root zone during salt-alkali stress. A larger absolute value indicates stronger soil water suction and lower water content. However, brackish water leaching requires the existing pore water in the soil to form a continuous downward flow to drive salt transport to deeper layers. If the soil water content is too low, the injected brackish water will be preferentially adsorbed and retained in the surface pores by the soil matrix potential gradient, failing to form a penetrating leaching front. Therefore, this function establishes a piecewise linearly increasing mapping based on the absolute value of the matrix potential: when | |less than or equal to| At 33 kPa, the soil moisture content is above field capacity, and gravity water can drain freely, so leaching is not initiated; when | | Between 33 kPa and 50 kPa, the soil is in a slightly arid state, and the leaching intensity increases linearly from a minimum of 2 L / (m·h) to a moderate 4 L / (m·h) to match the minimum injection flux required to match the degree of pore unsaturation; when | | When the soil is in a moderately dry state between 50 kPa and 80 kPa, the leaching intensity increases linearly from 4 L / (m·h) to a maximum of 6 L / (m·h); when | When the soil pressure exceeds 80 kPa, it is severely arid. The leaching intensity is maintained at the upper limit of 6 L / (m·h) to ensure sufficient flux to penetrate the dry soil layer, while avoiding further increases that could lead to instantaneous waterlogging and oxygen depletion in the root zone. Its function is to adaptively adjust the leaching flux based on the actual aridity of the root zone soil at the time of stress, ensuring that the slightly saline water forms a stable downward seepage flow driven by gravity gradient to leach and replace soluble salts in the root zone, achieving precise salt control without causing secondary waterlogging. Then, the pulse injection controller drives the electric diaphragm pump to inject slightly saline water with a preset mineralization level into the potato root zone in a pulse manner according to the initial leaching intensity. This preset mineralization level is selected as 3 g / L based on the local irrigation water salt concentration. The duration of each pulse injection is set to 10 minutes. After each pulse injection, the electric diaphragm pump is turned off to pause injection and enter a salt rebalancing waiting period. During this period, the pump is operated by... A soil conductivity sensor continuously monitors the soil conductivity in the root zone at a sampling frequency of once per minute. The real-time rate of change of soil conductivity is obtained by dividing the difference between two adjacent sampling values ​​by the sampling interval. This real-time rate of change reflects the speed at which soil salts in the root zone redistribute under the influence of the concentration gradient after the leaching pulse stops. When the absolute value of this real-time rate of change decays below a preset threshold, it is determined that the salt rebalancing state in the root zone has been achieved, and the soil conductivity at this point is read. The preset threshold can be set according to actual needs; for example, it can be set to 0.05 dS / m / min. This is because salt ions in the soil solution in the root zone redistribute under the influence of the concentration gradient... Driven by temperature, the salts diffuse from high-concentration micro-regions to low-concentration micro-regions, accompanied by the slow dissolution and replenishment of soluble salts in the solid phase. The rate of change in conductivity exhibits an exponential decay over time. In the initial stage, the rapid dissolution and exchange at the interface between the soil solution and solid salts leads to a high rate of change in conductivity, typically reaching 0.3–0.5 dS / m / min. As the liquid phase salts become more homogenized and the solid phase dissolution reaches equilibrium, the rate of change gradually decreases. Experiments show that when the rate of change in conductivity decays to below 0.05 dS / m / min, more than 95% of the salt exchange between the solid and liquid phases has been completed. Further extending the equilibrium waiting time does not significantly improve the degree of salt homogenization. Therefore, this value is determined as the threshold for determining the salt rebalancing state. The root zone salt rebalancing state refers to the stable state in which the salt in the root zone soil solution has completed the solid-liquid phase exchange and spatial homogenization. The soil conductivity read at this time is compared with the preset safe conductivity range, which is set to 1.5 dS / m to 2.5 dS / m based on the salt tolerance threshold of potato varieties. When the soil conductivity after salt rebalancing is determined to be higher than the upper limit of the preset safe conductivity range of 2.5 dS / m, the pulse cycle trigger logic restarts the electric diaphragm pump to continue to pulse-inject slightly saline water at the initial leaching intensity, forming an intermittent leaching cycle.

[0074] It should be noted that the intermittent leaching cycle in this application refers to a periodic brackish water leaching operation cycle consisting of alternating pulse injection periods and salt rebalancing waiting periods. This scheme uses the starting matrix potential locked at the time of composite stress signal generation as the leaching initiation benchmark. The initial leaching intensity is adaptively determined based on the degree of soil moisture deficit when stress occurs through the matrix potential-leaching intensity function. After injecting brackish water with a preset mineralization in a pulse manner, the injection is paused. The achievement of the root zone salt rebalancing state is determined by the real-time rate of change of soil conductivity decaying to a threshold. Whether the soil conductivity after rebalancing falls back to a safe range is used as the cyclic criterion for whether to continue pulse injection. Thus, a closed-loop adaptive intermittent leaching cycle is constructed, which is driven by soil matrix potential to adapt the leaching intensity and by the salt rebalancing state to drive the pulse intermittent rhythm. This achieves a precise salt control and desalination process that matches the leaching flux with soil drought and synchronizes the leaching interval with the salt dissolution and redistribution dynamics. It avoids excessive deep leakage and nutrient loss caused by continuous leaching and also prevents blind intervention of soil moisture status by fixed-cycle leaching.

[0075] In the root zone leaching module, when the cultivation monitoring module detects that the soil conductivity has fallen back to the preset safe conductivity range, the intermittent leaching operation with brackish water is terminated and the leaching duration is recorded. This is achieved through the following steps:

[0076] During the intermittent leaching cycle, the soil conductivity in the root zone was continuously monitored, and the soil conductivity after each pulse injection and salt rebalancing was compared with the preset safe conductivity range.

[0077] When it is determined that the soil electrical conductivity after the salinity rebalancing has fallen back to the preset safe electrical conductivity range, the brackish water injection channel is closed and the intermittent rinsing cycle is terminated.

[0078] Extract the time difference from the moment corresponding to the start of the matrix potential to the moment when the brackish water injection channel is closed, and record it as the rinsing duration.

[0079] In specific implementation, firstly, during the intermittent leaching cycle, a soil conductivity sensor continuously monitors the soil conductivity in the root zone at a preset sampling frequency. After each pulse injection by the electric diaphragm pump and the entry into the salinity rebalancing waiting period, the salinity rebalancing determination unit continuously calculates the difference between two adjacent sampling values ​​divided by the sampling interval to obtain the real-time rate of change of soil conductivity. When the absolute value of this real-time rate of change decays below a preset threshold, it is determined that the salinity rebalancing state in the root zone has been achieved. At this time, a comparator circuit compares the measured soil conductivity value at the current sampling moment with the preset safe conductivity range stored in the threshold register. The safe electrical conductivity range is set to 1.5 dS / m to 2.5 dS / m based on the salt tolerance threshold of potato varieties. Then, when the measured soil electrical conductivity after salt rebalancing is determined to be less than or equal to the upper limit of the preset safe electrical conductivity range of 2.5 dS / m, the cycle termination control logic sends a shutdown command to the drive circuit of the electric diaphragm pump to cut off the brackish water injection channel and terminate the intermittent rinsing cycle. Finally, the duration extraction timer reads the start matrix potential corresponding time and the brackish water injection channel shutdown time recorded by the system clock, calculates the time difference by subtracting the start time timestamp from the shutdown timestamp, and records the time difference as the rinsing duration.

[0080] It should be noted that the leaching duration in this application refers to the total operation time parameter from the start of the intermittent leaching operation triggered by the brackish water until the soil conductivity in the root zone falls back to the safe range.

[0081] The nutrient solution delivery module 400 is used to determine the injection ratio and injection duration of calcium-containing and potassium-containing nutrient solutions based on the leaching duration and the lowest photochemical vegetation index during the generation process of the composite stress signal, and then deliver the calcium-containing and potassium-containing nutrient solutions to the potato root zone.

[0082] In the nutrient solution delivery module, the injection ratio and injection duration of the calcium- and potassium-containing nutrient solutions are determined based on the leaching duration and the lowest photochemical vegetation index during the generation of the composite stress signal, using the following steps:

[0083] The lowest photochemical vegetation index recorded during the generation of the composite stress signal was obtained, and the leaching duration recorded by the root zone leaching module was extracted.

[0084] Substitute the rinsing duration into the pre-constructed rinsing ion loss function to calculate the estimated loss of effective potassium ions and effective calcium ions in the root zone.

[0085] Based on the estimated loss and the minimum photochemical vegetation index, the potassium-calcium molar ratio is inverted through a preset stress recovery nutrient ratio model, and this potassium-calcium molar ratio is used as the injection ratio of calcium-containing and potassium-containing nutrient solutions.

[0086] Using the rinsing duration as a baseline variable, and considering the deviation of the minimum photochemical vegetation index from the preset optimal vegetation index, the injection duration is calculated using a recovery duration function.

[0087] In specific implementation, firstly, from the frame-by-frame photochemical vegetation index time-series data stored during the generation of the composite stress confirmation signal, the photochemical vegetation index at all sampling times within the composite stress period is traversed, and the minimum value is selected and recorded as the lowest photochemical vegetation index. The lowest photochemical vegetation index refers to the light energy utilization efficiency parameter reflecting the most severe damage to the leaf photosynthetic apparatus during stress. Simultaneously, the leaching duration is obtained. Secondly, the leaching duration is input into a pre-constructed leaching ion loss function for calculation. This leaching ion loss function is a first-order exponential decay model obtained by fitting data from a column leaching experiment in saline-alkali loam, and its expression is: ,in, To estimate the effective ion loss, that is, the amount of plant-available potassium or calcium ions lost during leaching as they migrate out of the root zone with the downstream water flow. The initial effective ion content in the root zone was determined based on soil samples from the unstressed area, with potassium ions at 120 mg / kg and calcium ions at 800 mg / kg. k was the leaching rate constant, calculated based on soil column test results, with potassium ions at 0.15 min⁻¹ and calcium ions at 0.08 min⁻¹. T was the input leaching duration. The estimated effective potassium ion and effective calcium ion losses in the root zone were calculated by substituting the corresponding parameters for potassium and calcium ions, respectively. Then, the calculated estimated effective potassium ion and effective calcium ion losses, along with the minimum photochemical vegetation index, were input into a preset stress recovery nutrient ratio model. This model is a multiple regression equation established based on potato saline-alkali stress recovery test data, and its form is as follows: ,in, The potassium-calcium molar ratio, and The estimated losses of available potassium ions and available calcium ions are respectively. The minimum photochemical vegetation index is defined as denoted by , and a, b, and c are regression coefficients, calibrated based on experimental data and set to 0.35, 2.10, and 0.50, respectively. The potassium-calcium molar ratio calculated through this equation is the injection ratio of calcium-containing and potassium-containing nutrient solutions. This injection ratio refers to the ratio of the molar concentration of potassium ions to the molar concentration of calcium ions in the nutrient solution. Finally, using the leaching duration as a baseline variable, the deviation of the minimum photochemical vegetation index from the preset optimal vegetation index is calculated. The preset optimal vegetation index is set to 0.08 based on the measured value of the canopy of healthy potatoes without stress. The optimal vegetation index refers to the reference value of the photochemical vegetation index under the condition of a healthy potato canopy without salt and alkali stress, with suitable water and fertilizer supply, and with complete photosynthetic function. It is used to characterize the xanthophyll cycle in potato leaves when it is in normal dynamic equilibrium. The baseline level for the conversion process to maize xanthine is determined by the preset optimal vegetation index using measured canopy spectral data of healthy potatoes under normal water and fertilizer management conditions. The photochemical vegetation index reflects the conversion status of xanthine to maize xanthine in the leaf xanthophyll cycle. Healthy, unstressed potatoes have intact canopy photosynthetic structures and normal light energy utilization efficiency. The difference in reflectance at the two characteristic wavelengths of 531nm and 570nm keeps the photochemical vegetation index value stable within the range of 0.06 to 0.10. After statistical analysis of multiple field trials, the median value of 0.08 in this range was taken as the optimal vegetation index threshold for the variety. This value avoids misjudging normal conditions as stress due to high thresholds caused by variety differences or measurement noise, and also prevents underestimation of mild stress due to low thresholds. The leaching duration and deviation amplitude are input into the recovery duration function. The calculation is performed to obtain the injection duration, where... To restore the delay index, a value of 0.65 was used based on the potato stress recovery rate test data. The deviation range is represented by T, which is the input leaching duration. The principle of this recovery duration function is that while leaching removes salt from the root zone, it inevitably causes the loss of effective mineral nutrients. Plants need to continuously replenish calcium and potassium nutrients and undergo a certain physiological repair process to recover their photosynthetic capacity from compound stress. The longer the leaching duration, the more severe the salt and alkali stress, the greater the ion leaching from the root zone, and the longer the base duration for nutrient replenishment. Therefore, the leaching duration is used as the benchmark variable. At the same time, the deviation of the minimum photochemical vegetation index from the optimal vegetation index directly reflects the degree of damage to the photosynthetic apparatus caused by ion poisoning and osmotic stress. The greater the deviation range, the longer the recovery time required. Therefore, a power function of the deviation range is introduced as an amplification factor for the benchmark duration. The amplification slope is adjusted by the recovery delay index γ, so that the injection duration increase is more significant when the stress is severe and the deviation range is large, while the injection duration is close to the benchmark leaching duration when the stress is mild and the deviation range is small. Its function is to adaptively determine the duration of nutrient solution replenishment based on the severity of stress and the degree of damage to the photosynthetic apparatus, ensuring that the effective concentration of calcium and potassium ions in the root zone can meet the physiological needs of photosynthetic pigment synthesis and stomatal function recovery, while avoiding excessive injection time that would lead to nutrient solution waste and nutrient accumulation imbalance in the root zone.

[0088] It should be noted that the injection duration in this application refers to the total duration of continuous delivery of calcium and potassium nutrient solutions to the potato root zone.

[0089] In the nutrient solution delivery module, the calcium- and potassium-containing nutrient solutions are delivered to the potato root zone using the following steps:

[0090] According to the injection ratio, the intake volumes of calcium nitrate mother liquor and potassium nitrate mother liquor of preset concentrations are respectively measured, mixed in the nutrient solution mixing chamber and diluted with irrigation water to the target working concentration to obtain calcium-containing and potassium-containing nutrient solutions.

[0091] After the brackish water injection channel is closed, the nutrient solution delivery channel is switched, and the calcium- and potassium-containing nutrient solutions are delivered to the potato root zone at a preset low-pressure drip irrigation rate for the duration of injection.

[0092] In specific implementation, firstly, the injection ratio execution unit reads the potassium-calcium molar ratio, i.e., the injection ratio, output by the stress recovery nutrient ratio model. Based on this injection ratio, it calculates the volume of calcium nitrate mother liquor and potassium nitrate mother liquor required per unit volume of irrigation water. The preset concentration of calcium nitrate mother liquor is 1.0 mol / L (prepared with Ca(NO3)2·4H2O), and the preset concentration of potassium nitrate mother liquor is 1.0 mol / L (prepared with KNO3). For example, when the injection ratio, i.e., the potassium-calcium molar ratio, is 0.8, each liter of irrigation water needs to absorb 0.8 ml of potassium nitrate mother liquor and 1.0 ml of calcium nitrate mother liquor. The programmable logic controller drives the first precision metering pump corresponding to the calcium-based nutrient solution storage tank and the second precision metering pump corresponding to the potassium-based nutrient solution storage tank to simultaneously absorb their respective calculated volumes and inject them into the nutrient solution mixing chamber. The nutrient solution mixing chamber adopts an online mixing chamber with a Venturi jet mixing structure, utilizing the negative pressure generated by the flow of irrigation water. The mother liquor is drawn in under pressure and turbulent mixing is completed. Simultaneously, the irrigation water supply valve is opened to add irrigation water to dilute it to the target working concentration. This target working concentration is set according to the recommended fertilization concentration during the potato vegetative growth period, with a total salt concentration not exceeding 2.0 g / L. Thus, calcium- and potassium-containing nutrient solutions are obtained at the outlet of the mixing chamber. Subsequently, after the circulation termination control logic of the rhizosphere regulation module confirms that the brackish water injection channel has been closed, the path switching unit drives the three-way solenoid valve to cut off the brackish water channel and open the nutrient solution delivery channel, introducing the calcium- and potassium-containing nutrient solutions from the outlet of the mixing chamber into the drip irrigation pipeline system. The variable frequency constant pressure pump maintains a preset low-pressure drip irrigation flow rate, which is set according to the potato root zone drip irrigation design specifications at 1.5 liters per meter of root row length per hour. The injection duration calculated by the recovery duration function is the duration, and the calcium- and potassium-containing nutrient solutions are uniformly delivered to the potato root zone at this low-pressure drip irrigation flow rate to complete the nutrient supply during the stress recovery period.

[0093] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0094] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A growth real-time monitoring and cultivation regulating system for saline and alkaline land potato cultivation, characterized in that, The system comprises: a cultivation monitoring module for monitoring soil parameters at the same depth of the potato root zone in saline-alkali soil, spectral reflectance characteristics of the potato canopy, and leaf thermal infrared images; a stress signal generation module for determining a compound stress signal representing the synergistic effect of osmotic stress and ion toxicity on potatoes when the soil parameters are higher than the corresponding preset soil threshold, according to the canopy spectral reflectance characteristics combined with the leaf thermal infrared images; a root zone leaching module for starting intermittent brackish water leaching of the potato root zone when the soil matric potential corresponding to the moment when the compound stress signal is generated is used as the starting matric potential, and terminating the intermittent brackish water leaching and recording the leaching duration when the soil conductivity monitored by the cultivation monitoring module falls back to the preset safe conductivity interval; a nutrient solution delivery module for determining the injection ratio and injection duration of calcium-containing and potassium-containing nutrient solutions according to the leaching duration and the minimum photochemical vegetation index during the generation of the compound stress signal, and then delivering the calcium-containing and potassium-containing nutrient solutions to the potato root zone.

2. A growth monitoring and cultivation regulating system for saline and alkaline land potato cultivation as claimed in claim 1, wherein, In the cultivation monitoring module, soil parameters at the same depth of the potato root zone in saline-alkali soil, spectral reflectance characteristics of the potato canopy, and leaf thermal infrared images are monitored: a multi-source sensing probe is arranged at the same depth of the potato root zone to collect soil conductivity and soil matric potential, and to obtain air temperature of the potato canopy, thereby generating soil parameters at the same depth of the potato root zone in saline-alkali soil; a multispectral imager mounted on a movable platform is used to collect spectral reflectance characteristics of the potato canopy in the visible light to near-infrared band and leaf thermal infrared images of the potato canopy within the same time window of collecting the soil parameters.

3. A real time monitoring and cultivation regulating system for saline and alkaline land potato cultivation as claimed in claim 1 wherein, In the stress signal generation module, when the soil parameters are higher than the corresponding preset soil threshold, a compound stress signal representing the synergistic effect of osmotic stress and ion toxicity on potatoes is determined according to the canopy spectral reflectance characteristics combined with the leaf thermal infrared images, which specifically includes: soil conductivity and soil matric potential in the soil parameters are obtained and compared with the corresponding preset soil threshold, the preset soil threshold includes a preset matric potential threshold and a preset conductivity threshold, a primary saline-alkali stress signal is generated when the soil matric potential is lower than the preset matric potential threshold and the soil conductivity is higher than the preset conductivity threshold; in the state of generating the primary saline-alkali stress signal, a photochemical vegetation index is determined according to the canopy spectral reflectance characteristics, and a canopy-air temperature difference is obtained according to the difference between the average canopy temperature of the preset leaf area in the leaf thermal infrared image and the air temperature of the potato canopy; a compound stress signal representing the synergistic effect of osmotic stress and ion toxicity on potatoes is generated within the period when the photochemical vegetation index is lower than the preset vegetation index threshold and the canopy-air temperature difference exceeds the preset temperature difference threshold.

4. A growth monitoring and cultivation regulating system for saline and alkaline land potato cultivation as claimed in claim 3 wherein, In the stress signal generation module, a compound stress signal representing the synergistic effect of osmotic stress and ion toxicity on potatoes is generated within the period when the photochemical vegetation index is lower than the preset vegetation index threshold and when the canopy-air temperature difference exceeds the preset temperature difference threshold, which specifically includes: Within a continuous time window, when it is determined that the crown temperature difference exceeds a preset temperature difference threshold and the photochemical vegetation index is continuously lower than a preset vegetation index threshold, it is confirmed as a period of combined stress for potatoes, where stomatal closure temperature rise dominated by osmotic stress and photosynthetic pigment degradation dominated by ion toxicity. The crown temperature difference and photochemical vegetation index during the combined stress period were normalized and weighted to generate a combined stress signal.

5. A growth monitoring and cultivation regulating system for saline and alkaline land potato cultivation as claimed in claim 1, wherein, In the root zone leaching module, in response to the composite stress signal, the soil matrix potential corresponding to the time the composite stress signal is generated is used as the starting matrix potential to initiate the intermittent leaching operation of slightly saline water on the potato root zone. Specifically, this includes: Receive the composite stress signal and use the root zone soil matrix potential corresponding to the time when the composite stress signal is generated as the starting matrix potential; The initial rinsing intensity is determined by comparing the starting matrix potential with the corresponding threshold in the preset matrix potential-rinsing intensity function. According to the initial leaching intensity, slightly saline water with a preset mineralization degree is injected into the potato root zone in a pulse manner. After each injection pulse, the injection is paused, and the salinity rebalancing state of the root zone is determined by the real-time change rate of the soil conductivity. When the soil conductivity monitored under the salinity rebalancing state is higher than the upper limit of the preset safe conductivity range, brackish water is pulsed again at the initial leaching intensity to form an intermittent leaching cycle.

6. A growth monitoring and cultivation regulating system for saline and alkaline land potato cultivation as claimed in claim 1, wherein, In the root zone leaching module, when the cultivation monitoring module detects that the soil conductivity has fallen back to the preset safe conductivity range, the intermittent leaching operation with brackish water is terminated and the leaching duration is recorded. Specifically, this includes: During the intermittent leaching cycle, the soil conductivity in the root zone was continuously monitored, and the soil conductivity after each pulse injection and salt rebalancing was compared with the preset safe conductivity range. When it is determined that the soil electrical conductivity after the salinity rebalancing has fallen back to the preset safe electrical conductivity range, the brackish water injection channel is closed and the intermittent rinsing cycle is terminated. Extract the time difference from the moment corresponding to the start of the matrix potential to the moment when the brackish water injection channel is closed, and record it as the rinsing duration.

7. A real time monitoring and cultivation regulating system for saline and alkaline land potato cultivation as claimed in claim 1 wherein, In the cultivation monitoring module, the multi-source sensing probe includes a conductivity sensor and a tensiometer-type matrix potential sensor.

8. A growth monitoring and cultivation regulating system for saline and alkaline land potato cultivation as claimed in claim 1, wherein, In the nutrient solution delivery module, determining the injection ratio and injection duration of calcium- and potassium-containing nutrient solutions based on the leaching duration and the lowest photochemical vegetation index during the generation of the composite stress signal specifically includes: The lowest photochemical vegetation index recorded during the generation of the composite stress signal was obtained, and the leaching duration recorded by the root zone leaching module was extracted. Substitute the rinsing duration into the pre-constructed rinsing ion loss function to calculate the estimated loss of effective potassium ions and effective calcium ions in the root zone. Based on the estimated loss and the minimum photochemical vegetation index, the potassium-calcium molar ratio is inverted through a preset stress recovery nutrient ratio model, and this potassium-calcium molar ratio is used as the injection ratio of calcium-containing and potassium-containing nutrient solutions. Using the rinsing duration as a baseline variable, and considering the deviation of the minimum photochemical vegetation index from the preset optimal vegetation index, the injection duration is calculated using a recovery duration function.

9. A growth monitoring and cultivation regulating system for saline and alkaline land potato cultivation as claimed in claim 1, wherein, In the nutrient solution delivery module, delivering the calcium- and potassium-containing nutrient solution to the potato root zone specifically includes: According to the injection ratio, the intake volumes of calcium nitrate mother liquor and potassium nitrate mother liquor of preset concentrations are respectively measured, mixed in the nutrient solution mixing chamber and diluted with irrigation water to the target working concentration to obtain calcium-containing and potassium-containing nutrient solutions. After the brackish water injection channel is closed, the nutrient solution delivery channel is switched, and the calcium- and potassium-containing nutrient solutions are delivered to the potato root zone at a preset low-pressure drip irrigation rate for the duration of injection.

10. A growth monitoring and cultivation regulating system for saline and alkaline land potato cultivation as claimed in claim 1, wherein, In the cultivation monitoring module, uncooled focal plane array thermal infrared cameras are used to acquire thermal infrared images of potato canopy leaves.

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