Non-invasive plant moisture condition monitoring device and monitoring method
By using a non-invasive plant water monitoring device, which measures changes in leaf turgor pressure using magnets and Hall sensors, and combining this with temperature compensation, the problems of non-destructiveness and accuracy of existing monitoring methods are solved, enabling efficient and low-cost monitoring of plant water status.
Patent Information
- Application Number
- CN202511225792.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-29
- Publication Date
- 2025-11-28
AI Technical Summary
Existing methods for monitoring plant water status are poorly non-destructive and have low accuracy, making it difficult to achieve long-term, non-destructive, and accurate monitoring.
A non-invasive plant moisture monitoring device is used, which uses a magnet end and a sensing end to clamp the leaf without a main vein. The magnetic field change caused by the change in leaf turgor pressure is measured by a Hall sensor, and the plant moisture status is calculated by combining the temperature compensation mechanism.
It enables non-destructive and accurate monitoring of plant moisture status, is applicable to different plant species and growth stages, reduces hardware costs, allows for long-term continuous observation, and provides rapid feedback on moisture status, thus providing a basis for precision irrigation.
Smart Images
Figure CN121027286A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of plant condition monitoring technology, and in particular to a non-invasive device and method for monitoring plant water status. Background Technology
[0002] Plant water status affects their growth, development, yield, and quality; therefore, timely and accurate diagnosis of plant water status is crucial for plant production and irrigation management. Currently, methods for diagnosing plant water status mainly fall into two categories. The first is based on monitoring environmental factors that cause changes in plant water status, such as soil moisture and atmospheric water potential, indirectly indicating changes in plant water. These monitoring devices are relatively simple to operate and have a wide range of applications. However, the monitoring results are affected by the arrangement of measuring points and lack direct understanding of the plant's actual water changes. Researchers believe that direct measurement of the plant's own water information can more accurately reflect its water status, and based on this, they have proposed a second type of diagnostic method utilizing plant water physiological indicators. Existing monitoring indicators mainly include: relative leaf water content, stem and leaf water potential, stomatal conductance, stem flow, stem diameter, and canopy temperature.
[0003] Among these, leaf turgor pressure has become a new indicator for diagnosing plant water status due to its close relationship with stomatal conductance and water changes. However, further research is needed on the non-destructive measurement of leaf turgor pressure.
[0004] In summary, existing methods for diagnosing plant water status still need improvement in terms of applicability and accuracy. There is an urgent need to explore a new method that is simple to operate and can be used for long-term, non-destructive monitoring to obtain more accurate information on plant water status. Summary of the Invention
[0005] This invention provides a non-invasive device and method for monitoring plant moisture status, in order to solve the problems of poor non-destructiveness and low accuracy of existing plant moisture status monitoring devices.
[0006] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a non-invasive plant moisture status monitoring device, comprising a non-invasive probe and a measurement module. The non-invasive probe includes a magnetic end and a sensing end, which are clamped on the upper and lower surfaces of the part of the plant to be monitored. The sensing end acquires the voltage change value caused by the leaf turgor pressure change of the plant to be monitored within a predetermined time and transmits it to the measurement module. The measurement module calculates the moisture status of the part of the plant to be monitored based on the voltage change value.
[0007] The measurement module also includes a visualization unit. After calculating the water status of the plant to be monitored, the measurement module visualizes the magnetic field change value and the water status.
[0008] Furthermore, the plant part refers to the area of the leaf without a main vein of the plant to be monitored.
[0009] Furthermore, the magnet end is composed of a magnet, and the sensing end includes an iron sheet and a Hall sensor. The magnet at the magnet end and the iron sheet at the sensing end are magnetically clamped on the upper and lower surfaces of the veinless area of the plant leaf to be monitored.
[0010] Furthermore, the sensing end acquires the magnetic field change value caused by the leaf turgor pressure change of the plant under test within a predetermined time, and obtains the voltage change value based on the magnetic field change value combined with the Hall effect and the initial voltage value set by the non-invasive probe.
[0011] Furthermore, the measurement module calculates the moisture status of the plant part to be monitored based on the voltage change value, including: The measurement module obtains the relative turgor pressure value of the plant part to be monitored based on the voltage change value and the relationship model constructed based on the voltage change value and turgor pressure, and then determines the water status of the plant to be monitored based on the relative turgor pressure value.
[0012] Furthermore, the relationship between the voltage change value and the expansion pressure is represented by the following formula: ; in, Indicates relative expansion pressure; This indicates the voltage value output by the non-invasive probe; This indicates the initial voltage value set for the non-invasive probe. This indicates the voltage when the non-invasive probe is not clamped. These are dimensionless fitting parameters.
[0013] Furthermore, the sensing end also includes a temperature sensor. The measurement module acquires the ambient temperature collected by the temperature sensor. If the ambient temperature changes beyond a predetermined threshold within a predetermined time, the compensation turgor pressure is calculated based on the ambient temperature, the compensation coefficient, and the compensation intercept. The relative turgor pressure value is then corrected based on the compensation turgor pressure to obtain the corrected relative turgor pressure value. The water status of the plant to be monitored is determined based on the corrected relative turgor pressure value. If the ambient temperature does not change beyond the predetermined threshold within a predetermined time, no correction is required. The compensated expansion pressure is expressed by the following formula: ; in, Indicates compensation for expansion pressure; Indicates the compensation intercept; Indicates the compensation coefficient; This indicates the ambient temperature collected by the temperature sensor.
[0014] By performing the above operations, the rapid temperature changes can be avoided from affecting the voltage values obtained based on the Hall effect.
[0015] Secondly, the present invention also provides a non-invasive method for monitoring plant water status, the monitoring method comprising the following steps: Step 1: Wipe the surface of the leaves of the plant to be monitored, set the initial voltage value of the non-invasive probe, clamp the non-invasive probe on the upper and lower surfaces of the part of the plant to be monitored, and obtain the magnetic field change value caused by the leaf turgor pressure change between the upper and lower ends of the part of the plant to be monitored within a predetermined time. Based on the magnetic field change value, combined with the Hall effect and the initial voltage value set by the non-invasive probe, obtain the voltage change value. Step 2: The measurement module obtains the relative turgor pressure value of the plant part to be monitored based on the voltage change value and the relationship model constructed based on the voltage change value and turgor pressure, and then determines the water status of the plant to be monitored based on the relative turgor pressure value.
[0016] Furthermore, during step 2, the ambient temperature is collected by a temperature sensor set by a non-invasive probe. If the ambient temperature changes beyond a predetermined threshold within a predetermined time, the measurement module calculates the compensation turgor pressure based on the ambient temperature, the compensation coefficient, and the compensation intercept. The relative turgor pressure value is then corrected based on the compensation turgor pressure to obtain the corrected relative turgor pressure value. The water status of the plant to be monitored is determined based on the corrected relative turgor pressure value. If the ambient temperature does not exceed the predetermined threshold within a predetermined time, no correction is required.
[0017] Beneficial effects: This invention provides a non-invasive plant moisture monitoring device and method. It accurately measures magnetic field changes caused by leaf turgor pressure variations using a Hall sensor, and combines this with a temperature compensation mechanism to significantly improve the accuracy of plant moisture monitoring. The non-invasive probe magnetically clamps the upper and lower surfaces of the leaf, eliminating the need for puncture or damage to plant tissue, achieving truly non-destructive monitoring suitable for long-term continuous observation. The device is lightweight and easy to install (only requiring leaf clamping), and directly outputs moisture status via a linear relationship, lowering the barrier to entry. It can dynamically capture leaf turgor pressure changes within a predetermined time period, quickly providing feedback on plant moisture status and timely data for precision irrigation.
[0018] Applicable to various plant species and growth stages, this method expands the application scenarios of traditional methods in complex environments. Utilizing magnetic induction principles and general-purpose sensors (such as Hall elements), it reduces hardware costs while ensuring performance, facilitating widespread adoption. A built-in temperature sensor and compensation algorithm effectively eliminate interference from ambient temperature fluctuations on measurement results, ensuring data reliability. Attached Figure Description
[0019] Figure 1This is a schematic diagram of the module structure of a non-invasive plant moisture status monitoring device according to a specific embodiment of the present invention. Figure 2 This is a schematic diagram comparing the relative leaf turgor pressure and relative leaf water content of the pothos leaves in Embodiment 2 of the present invention; Figure 3 This is a schematic diagram comparing the relative leaf turgor pressure of the pothos leaf in Embodiment 2 of the present invention with the actual leaf turgor pressure; Figure 4 This is a schematic diagram illustrating the change of relative leaf turgor pressure over time in potted bok choy under conditions of full irrigation or slight water shortage, according to Embodiment 3 of the present invention. Figure 5 This is a schematic diagram illustrating the change of relative leaf turgor pressure over time in potted bok choy under moderate water shortage conditions according to Embodiment 3 of the present invention. Figure 6 This is a schematic diagram illustrating the change in relative leaf turgor pressure over time in potted bok choy under severe water shortage conditions, as described in Embodiment 3 of the present invention. Detailed Implementation
[0020] The technical solution of the present invention will be clearly and completely described below. 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.
[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.
[0022] A specific embodiment of the present invention is as follows: Please see Figure 1This invention provides a non-invasive plant moisture status monitoring device, including a non-invasive probe, a measurement module, a power supply module, and a data acquisition and transmission module. The non-invasive probe includes a magnetic end and a sensing end, which are clamped on the upper and lower surfaces of the part of the plant to be monitored. The sensing end acquires the voltage change value caused by the leaf turgor pressure change of the plant to be monitored within a predetermined time and transmits it to the measurement module. The measurement module calculates the moisture status of the part of the plant to be monitored based on the voltage change value. The power supply module is used to supply power to the non-invasive probe, the measurement module, and the data acquisition and transmission module.
[0023] The plant part is the area without the main vein of the leaf of the plant to be monitored. The magnet end is composed of magnets, and the sensing end includes an iron plate and a Hall sensor. The magnet at the magnet end and the iron plate at the sensing end are magnetically clamped on the upper and lower surfaces of the area without the main vein of the leaf of the plant to be monitored. The voltage change value acquired by the sensing end is obtained by first acquiring the magnetic field change value caused by the leaf turgor pressure change of the plant under test within a predetermined time. The voltage change value is then obtained by combining the magnetic field change value with the Hall effect and the initial voltage value set by the non-invasive probe.
[0024] The moisture status of the plant part to be monitored is determined by combining the voltage change value with the relationship model constructed based on the voltage change value and turgor pressure to obtain the relative turgor pressure value of the plant part to be monitored, and then determining the moisture status of the plant to be monitored based on the relative turgor pressure value.
[0025] Specifically, when determining the water status of the plant to be monitored based on the relative turgor pressure value, it is common knowledge to those skilled in the art that the water status of the plant to be monitored is determined based on the plant variety and the size of the individual plant. Thresholds can be set for the leaf water status of the plant to be monitored based on the aforementioned conditions, and the water status can be classified in combination with the thresholds. In addition, the degree of water deficit of the plant to be monitored can be characterized according to the type of diurnal variation curve.
[0026] The relationship between voltage change and inflation pressure is represented by the following formula: ; in, Indicates relative expansion pressure; This indicates the voltage value output by the non-invasive probe; This indicates the initial voltage value set for the non-invasive probe. This indicates the voltage when the non-invasive probe is not clamped. These are dimensionless fitting parameters.
[0027] The sensing end also includes a temperature sensor. The measurement module acquires the ambient temperature collected by the temperature sensor. If the ambient temperature changes beyond a predetermined threshold within a predetermined time, the compensation turgor pressure is calculated based on the ambient temperature, the compensation coefficient, and the compensation intercept. The relative turgor pressure value is then corrected based on the compensation turgor pressure to obtain the corrected relative turgor pressure value. The water status of the plant to be monitored is determined based on the corrected relative turgor pressure value. If the ambient temperature does not change beyond the predetermined threshold within a predetermined time, no correction is required. Compensating for expansion pressure is expressed by the following formula: ; in, Indicates compensation for expansion pressure; Indicates the compensation intercept; Indicates the compensation coefficient; This indicates the ambient temperature collected by the temperature sensor.
[0028] This application also provides a non-invasive method for monitoring plant water status, the method comprising the following steps: Step 1: Wipe the surface of the leaves of the plant to be monitored, set the initial voltage value of the non-invasive probe, clamp the non-invasive probe on the upper and lower surfaces of the part of the plant to be monitored, and obtain the magnetic field change value caused by the leaf turgor pressure change between the upper and lower ends of the part of the plant to be monitored within a predetermined time. Based on the magnetic field change value, combined with the Hall effect and the initial voltage value set by the non-invasive probe, obtain the voltage change value. Step 2: The measurement module obtains the relative turgor pressure value of the plant part to be monitored based on the voltage change value and the relationship model constructed based on the voltage change value and turgor pressure, and then determines the water status of the plant to be monitored based on the relative turgor pressure value.
[0029] During step 2, the ambient temperature is collected by a temperature sensor set by a non-invasive probe. If the ambient temperature changes beyond a predetermined threshold within a predetermined time, the measurement module calculates the compensation turgor pressure based on the ambient temperature, the compensation coefficient, and the compensation intercept. The relative turgor pressure value is then corrected based on the compensation turgor pressure to obtain the corrected relative turgor pressure value. The water status of the plant to be monitored is determined based on the corrected relative turgor pressure value. If the ambient temperature does not exceed the predetermined threshold within a predetermined time, no correction is required.
[0030] Example 2 In this embodiment, both the magnet end and the sensing end are cylinders with a bottom diameter of 15mm and a magnet end height of 2mm. The voltage A output by the non-invasive probe when it is not clamped is... Dimensionless fitting parameters The compensation intercept is 0.25. The value is 0.586, and the compensation coefficient is 287.960.
[0031] Please see Figures 2 to 3 The leaves of the pothos plant were saturated with water, and then the turgor pressure-volume curve was measured using the natural drying method. The true turgor pressure (TTP) was calculated using the formula "turgor pressure = water potential - osmotic potential". Simultaneously, a non-invasive probe was clamped onto the saturated leaves, and after the sensor reading stabilized, the output voltage Ri during the water loss process was continuously recorded until the leaves wilted. The analysis results are as follows: Figure 2 As shown, RTP is inversely proportional to the relative water content of the leaves (y = -1.1667x + 314.19). =0.967), the TTP descent gradient is relatively large. Analysis is performed using the logarithm of the actual leaf turgor pressure TTP, lnTTP. lnTTP is directly proportional to ΔRTP (the decrease ΔRTP is obtained by subtracting the initial value from the output value at each time period after removing the influence of the original leaf differences on the sensor) (y=-0.2512x-22.257, =0.956).
[0032] This indicates that the sensor's output value can sensitively measure changes in the moisture status of the leaves.
[0033] Example 3 Both the magnet end and the sensing end are cylinders with a bottom diameter of 15mm and a magnet end height of 2mm. The output voltage A value of the non-invasive probe when it is not clamped is... Dimensionless fitting parameters The compensation intercept is 0.25. The value is 0.586, and the compensation coefficient is 287.960.
[0034] An irrigation experiment was conducted by clamping the probe onto a potted bok choy plant. The signal characteristics of the non-invasive probe under different water conditions were analyzed to identify the sensor signal characteristic parameters.
[0035] Monitoring results as follows Figure 4-6 As shown, RTP exhibits three diurnal variation curves under different moisture conditions.
[0036] Please see Figure 4 Under conditions of full irrigation or slight water deficit, the overall RTP curve of pak choi exhibits a single-peak pattern of "high during the day and low at night." RTP gradually increases starting at 6:00, indicating a decrease in leaf turgor pressure; it reaches its peak around 12:00, then drops slightly but remains at a relatively high value, during which the leaf turgor pressure of pak choi reaches its lowest value of the day; RTP decreases around 20:00 until it tends to stabilize at a relatively low value during the night.
[0037] Please see Figure 5After irrigation was stopped for a period of time, the RTP was higher than that under full irrigation, and remained at a high value before sunrise. After sunrise, it showed a similar upward trend as under full irrigation, but an abnormal drop occurred between 12:00 and 14:00. Then it gradually rose again, reaching the second peak of the day at 20:00. The overall curve was "double peak".
[0038] Please see Figure 6 The bok choy leaves showed obvious wilting, indicating severe water deficiency. At this time, the diurnal variation trend of RTP was completely opposite to that during periods of full irrigation / slight water deficiency. The curve generally exhibited a "low during the day, high at night" pattern: RTP fluctuated at higher values between 0:00-5:00 and 20:00-24:00; after 5:00, RTP showed a downward trend, reaching its lowest value at 12:35, with a slight rebound during this period; after fluctuating at low values for about 1 hour, RTP began to rise again, stabilizing around 20:00.
[0039] The above results indicate that the RTP measured by the non-invasive plant water status monitoring device provided by the present invention can accurately reflect changes in plant water status by outputting different curve change types.
[0040] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A non-invasive device for monitoring plant water status, characterized in that, The device includes a non-invasive probe and a measurement module. The non-invasive probe includes a magnet end and a sensing end, which are clamped on the upper and lower surfaces of the part of the plant to be monitored. The sensing end acquires the voltage change value caused by the leaf turgor pressure change of the plant to be monitored within a predetermined time and transmits it to the measurement module. The measurement module calculates the water status of the part of the plant to be monitored based on the voltage change value.
2. The non-invasive plant moisture status monitoring device according to claim 1, characterized in that, The plant part referred to is the area of the leaf without the main vein of the plant to be monitored.
3. The non-invasive plant moisture status monitoring device according to claim 2, characterized in that, The magnet end is composed of a magnet, and the sensing end includes an iron sheet and a Hall sensor. The magnet at the magnet end and the iron sheet at the sensing end are magnetically clamped on the upper and lower surfaces of the veinless area of the plant leaf to be monitored.
4. The non-invasive plant moisture status monitoring device according to claim 3, characterized in that, The sensing end acquires the magnetic field change value caused by the leaf turgor pressure change of the plant under test within a predetermined time. The voltage change value is obtained based on the magnetic field change value combined with the Hall effect and the initial voltage value set by the non-invasive probe.
5. The non-invasive plant moisture status monitoring device according to claim 4, characterized in that, The measurement module calculates the moisture status of the plant parts to be monitored based on voltage change values, including: The measurement module obtains the relative turgor pressure value of the plant part to be monitored based on the voltage change value and the relationship model constructed based on the voltage change value and turgor pressure, and then determines the water status of the plant to be monitored based on the relative turgor pressure value.
6. The non-invasive plant moisture status monitoring device according to claim 5, characterized in that, The relationship between the voltage change and the inflation pressure is expressed by the following formula: ； in, Indicates relative expansion pressure; This indicates the voltage value output by the non-invasive probe; This indicates the initial voltage value set for the non-invasive probe. This indicates the voltage when the non-invasive probe is not clamped. These are dimensionless fitting parameters.
7. The non-invasive plant moisture status monitoring device according to claim 1, characterized in that, The sensing end also includes a temperature sensor. The measurement module acquires the ambient temperature collected by the temperature sensor. If the ambient temperature changes more than a predetermined threshold within a predetermined time, the compensation turgor pressure is calculated based on the ambient temperature, the compensation coefficient, and the compensation intercept. The relative turgor pressure value is then corrected based on the compensation turgor pressure to obtain the corrected relative turgor pressure value. The water status of the plant to be monitored is determined based on the corrected relative turgor pressure value. If the ambient temperature does not change more than a predetermined threshold within a predetermined time, no correction is required. The compensated expansion pressure is expressed by the following formula: ； in, Indicates compensation for expansion pressure; Indicates the compensation intercept; Indicates the compensation coefficient; This indicates the ambient temperature collected by the temperature sensor.
8. A non-invasive method for monitoring plant water status, applied to the non-invasive plant water status monitoring device according to any one of claims 1-7, characterized in that, The monitoring method includes the following steps: Step 1: Wipe the surface of the leaves of the plant to be monitored, set the initial voltage value of the non-invasive probe, clamp the non-invasive probe on the upper and lower surfaces of the part of the plant to be monitored, and obtain the magnetic field change value caused by the leaf turgor pressure change between the upper and lower ends of the part of the plant to be monitored within a predetermined time. Based on the magnetic field change value, combined with the Hall effect and the initial voltage value set by the non-invasive probe, obtain the voltage change value. Step 2: The measurement module obtains the relative turgor pressure value of the plant part to be monitored based on the voltage change value and the relationship model constructed based on the voltage change value and turgor pressure, and then determines the water status of the plant to be monitored based on the relative turgor pressure value.
9. The non-invasive method for monitoring plant water status according to claim 8, characterized in that, During step 2, the ambient temperature is collected by a temperature sensor set by a non-invasive probe. If the ambient temperature changes beyond a predetermined threshold within a predetermined time, the measurement module calculates the compensation turgor pressure based on the ambient temperature, the compensation coefficient, and the compensation intercept. The relative turgor pressure value is then corrected based on the compensation turgor pressure to obtain the corrected relative turgor pressure value. The water status of the plant to be monitored is determined based on the corrected relative turgor pressure value. If the ambient temperature does not exceed the predetermined threshold within a predetermined time, no correction is required.