CN116559383A - Photosynthetic rate detection method based on interaction of biochar returning root system and soil moisture and application thereof - Google Patents
Photosynthetic rate detection method based on interaction of biochar returning root system and soil moisture and application thereof Download PDFInfo
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Abstract
The invention belongs to the technical field of root system-soil moisture interaction detection, and particularly relates to a photosynthetic rate detection method based on interaction of biochar returning root system and soil moisture and application thereof. The invention uses a negative pressure irrigation method to ensure that the boundary moisture vibration period of the water-retaining area is consistent with the plant water absorption period; analyzing the moisture vibration characteristics of the boundary of the root system water-retaining area by using a frequency analysis method; a vibration model of the spring-mass system was used to establish the relationship between the frequency of moisture vibration and the photosynthetic rate of the plant. The method for detecting the photosynthetic rate is simple to operate, is little in environmental interference, can estimate the photosynthetic rate of the plant in time, and prevents water stress of crops; meanwhile, the method can solve the problems of difficult acquisition of root system-soil moisture interaction data, high analysis cost and the like.
Description
Technical Field
The invention belongs to the technical field of root system-soil moisture interaction detection, and particularly relates to a photosynthetic rate detection method based on interaction of biochar returning root system and soil moisture and application thereof, in particular to a photosynthetic rate detection method based on root system-soil moisture interaction and application thereof.
Background
The biochar is a porous carbon-containing solid produced by biomass pyrolysis, and the biochar can be returned to the field to increase carbon sink of soil, improve water and fertilizer retention capacity of the soil, and is one of important measures for sustainable development of agriculture and environment. The biochar is applied to the water-saving irrigation technology, so that the utilization efficiency of water resources can be improved, and the grain production in arid areas can be ensured. In the water-saving irrigation technology, the underground drip irrigation technology slowly conveys water to the root zone of crops by the capillary principle, and a limited water-retaining area is formed in the root zone of the crops. In the underground irrigation technology, the soil-root system water interaction is detected, the root system water absorption characteristic and the photosynthesis characteristic of crops are analyzed, and the method has important significance for fine water management in the underground drip irrigation technology.
Because of the space-time variability of water in soil, analyzing the water absorption activity of root systems is always a hot spot and a difficult point of research. The traditional root system water absorption analysis method generally adopts a model inversion method, and inversion Richards model parameters are carried out according to soil moisture data measured at a single point, so that the water absorption activity of crops is estimated. The problem with the conventional methods is that the spatiotemporal variation of the water uptake activity of the crop cannot be monitored in real time. High space-time resolution data is needed for resolving crop water absorption, and tomography techniques, such as: x-ray imaging, magnetic Resonance Imaging (MRI) and resistivity imaging (ERT) can acquire high spatial-temporal resolution data of crop root zones, and are widely used to characterize soil moisture changes caused by root system water absorption. However, it is difficult for the current image processing technology to distinguish the soil moisture change caused by root system water absorption and soil moisture redistribution. Moreover, the tomography technique is difficult to popularize in practical application.
Previous studies have also developed non-destructive methods for plant physiological stress, such as: the detection method of physiological stress indexes such as photosynthetic rate, stomatal conductance, leaf temperature and the like based on the thermal infrared image; a detection method for predicting plant water stress based on the mechanical characteristic change of the whole or partial organs of the plant. However, blade-based detection methods are susceptible to environmental interference, which presents difficulties for later data processing. Meanwhile, such methods require expensive detection equipment, and it is difficult to detect physiological stress signals of crops in time.
Disclosure of Invention
The invention aims to provide a photosynthetic rate detection method based on interaction of a biochar returning root system and soil moisture and application thereof, wherein the photosynthetic rate detection method can estimate the photosynthetic rate of plants in time, is simple to operate and is little in environmental interference; and the data acquisition is easier and the cost is lower.
The invention provides a photosynthetic rate detection method based on root system-soil moisture interaction, which comprises the following steps:
1) Carrying out negative pressure irrigation on plants, and estimating the size of a water-retaining area and the position of a wetting peak of the plant root system according to the negative pressure of the negative pressure irrigation;
2) Monitoring the moisture content of soil at the position of a wetting peak in the vertical direction of the water retention area and the central position of a plant root system to respectively obtain the change data of the moisture content of soil in the wetting area and at the dry-wet boundary of the water retention area and the time t;
3) Respectively performing fast Fourier transform on the soil moisture content-time t change data in the wet area and at the dry-wet boundary of the water retention area to respectively obtain soil moisture spectrum data in the wet area and at the dry-wet boundary;
4) Analyzing and obtaining the natural frequency omega caused by the water absorption activity of plants according to the soil moisture spectrum data at the dry-wet boundary n ；
Performing inverse Fourier transform on root system water absorption frequency in the soil moisture spectrum data in the wetting zone, and recovering vibration waveforms caused by plant water absorption to obtain vibration amplitude A;
5) Obtaining photosynthetic rate in a predetermined relation I；
A relation I; wherein (1)>And->Depending on the initial conditions, in estimating the photosynthetic rate of a certain interval +.>The value may be 0.
Preferably, applying biochar to the soil is further included before performing the negative pressure irrigation.
Preferably, the negative pressure irrigation is performed by drip irrigation and a drip irrigation pipe is connected with an irrigation point source; and an irrigation point source is arranged at the planting position of each plant.
Preferably, the method of estimating in step 1) comprises: setting irrigation amounts of different levels for irrigation point sources in soil, and observing the infiltration distance after each irrigation is finished; and drawing a relation curve of the infiltration distance and the irrigation amount, and estimating the size of the water-retaining area and the position of the wetting peak according to the relation curve.
Preferably, the monitoring described in step 2) is performed using a soil moisture sensor; and respectively burying the soil moisture sensor into the position of a wetting peak in the vertical direction of the water retaining area and the center position of a plant root system.
Preferably, before performing said step 4), the fundamental frequency in the background environment of the soil moisture content-time t-varying data in said wetted area and the frequency of the dc component and moisture redistribution are eliminated.
The invention also provides application of the photosynthetic rate detection method in water-saving irrigation.
Preferably, the water-saving irrigation comprises underground drip irrigation.
Preferably, the subsurface drip irrigation comprises fine moisture management of subsurface drip irrigation.
The beneficial effects are that:
the invention provides a photosynthetic rate detection method based on root system-soil moisture interaction, which comprises the following steps:
1) Carrying out negative pressure irrigation on plants, and estimating the size of a water-retaining area and the position of a wetting peak of the plant root system according to the negative pressure of the negative pressure irrigation;
2) Monitoring the moisture content of soil at the position of a wetting peak in the vertical direction of the water retention area and the central position of a plant root system to respectively obtain the change data of the moisture content of soil in the wetting area and at the dry-wet boundary of the water retention area and the time t;
3) Respectively performing fast Fourier transform on the soil moisture content-time t change data in the wet area and at the dry-wet boundary of the water retention area to respectively obtain soil moisture spectrum data in the wet area and at the dry-wet boundary;
4) Analyzing and obtaining the natural frequency omega caused by the water absorption activity of plants according to the soil moisture spectrum data at the dry-wet boundary n ；
Performing inverse Fourier transform on root system water absorption frequency in the soil moisture spectrum data in the wetting zone, and recovering vibration waveforms caused by plant water absorption to obtain vibration amplitude A;
5) Obtaining photosynthetic rate in a predetermined relation I；
A relation I; wherein (1)>And->Depending on the initial conditions, in estimating the photosynthetic rate of a certain interval +.>The value may be 0.
The invention uses a negative pressure irrigation method to ensure that the boundary moisture vibration period of the water-retaining area is consistent with the plant water absorption period; analyzing the moisture vibration characteristics of the boundary of the root system water-retaining area by using a frequency analysis method; establishing a relationship between the moisture vibration frequency and the plant photosynthetic rate using a vibration model of a spring-mass system; the method for detecting the photosynthetic rate is simple to operate, is little in environmental interference, can estimate the photosynthetic rate of the plant in time, and prevents water stress of crops; meanwhile, the method can solve the problems of difficult acquisition of root system-soil moisture interaction data, high analysis cost and the like. When the physical stress exists as an object, the photosynthetic rate is changed, so that the management measures can be timely found and targeted adjustment and control. When the irrigation negative pressure can not meet the growth requirement of crops, the photosynthesis rate is reduced, and the irrigation negative pressure can be timely increased, so that fine moisture management is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments will be briefly described below.
FIG. 1 is a schematic diagram of a photosynthetic rate detection method based on root system-soil moisture interaction of example 1;
FIG. 2 is a flowchart of a photosynthetic rate detection method based on root system-soil moisture interaction of example 1;
FIG. 3 is a graph showing the soil moisture response of each soil moisture sensor 88 to 93 days after planting of tomato seedlings in example 1;
FIG. 4 is a spectrum of soil moisture vibration at a water source in example 1;
FIG. 5 is a spectrum diagram of other sensor positions in example 1;
fig. 6 is a waveform and spectrum of the soil moisture at the filtered water source in example 1.
Detailed Description
The invention provides a photosynthetic rate detection method based on root system-soil moisture interaction, which comprises the following steps:
1) Carrying out negative pressure irrigation on plants, and estimating the size of a water-retaining area and the position of a wetting peak of the plant root system according to the negative pressure of the negative pressure irrigation;
2) Monitoring the moisture content of soil at the position of a wetting peak in the vertical direction of the water retention area and the central position of a plant root system to respectively obtain the change data of the moisture content of soil in the wetting area and at the dry-wet boundary of the water retention area and the time t;
3) Respectively performing fast Fourier transform on the soil moisture content-time t change data in the wet area and at the dry-wet boundary of the water retention area to respectively obtain soil moisture spectrum data in the wet area and at the dry-wet boundary;
4) Analyzing and obtaining the natural frequency omega caused by the water absorption activity of plants according to the soil moisture spectrum data at the dry-wet boundary n ；
Performing inverse Fourier transform on root system water absorption frequency in the soil moisture spectrum data in the wetting zone, and recovering vibration waveforms caused by plant water absorption to obtain vibration amplitude A;
5) Obtaining photosynthetic rate in a predetermined relation I；
A relation I; wherein (1)>And->Depending on the initial conditions, in estimating the photosynthetic rate of a certain interval +.>The value may be 0.
The present invention preferably applies biochar to the soil and mixes it uniformly to improve the water holding capacity of the soil. The amount of biochar applied in the present invention is not particularly limited, and it may be added conventionally according to the experience of those skilled in the art. The soil according to the present invention preferably includes any soil other than sand.
After the biochar is applied, an irrigation point source is preferably buried in the soil to which the biochar is applied, an irrigation point source is arranged at the planting position of each plant, and the irrigation point source is preferably connected with a drip irrigation pipe for negative pressure irrigation so as to realize negative pressure irrigation on the plants, and meanwhile, a stable water-retaining area is formed around a root system in the plant growth process. In the present invention, it is preferable to set irrigation point sources first and then to plant plants. In the invention, crop water absorption is the main driving force of soil-root system water migration or biochar-soil-root system water migration, so that the vibration period of the soil water content at the boundary of the water-retaining area is consistent with the root system water absorption period.
After the water retention area is obtained, the size of the water retention area of the plant root system and the position of the wetting peak are estimated and obtained according to the negative pressure of the negative pressure irrigation. The method of estimation according to the invention preferably comprises: setting irrigation amounts of different levels for irrigation point sources in soil, and observing the infiltration distance after each irrigation is finished; and drawing a relation curve of the infiltration distance and the irrigation amount, and estimating the size of the water-retaining area and the position of the wetting peak according to the relation curve. The invention preferably removes relatively dry soil prior to observing the infiltrative distance to facilitate observation at the infiltrative distance.
After the size of the water retention area and the position of the wetting peak are obtained, the invention monitors the position of the wetting peak in the vertical direction of the water retention area and the soil moisture content in the center position of the plant root system, and respectively obtains the change data of the soil moisture content-time t in the wetting area and at the dry-wet boundary of the water retention area. The monitoring is preferably performed by using a soil moisture sensor, and particularly, the soil moisture sensor is preferably respectively embedded in the position of a wetting peak in the vertical direction of the water retention area and the central position of a plant root system. The source and the model of the soil moisture sensor are not particularly limited, and the conventional capacitive soil moisture sensor in the field can be adopted. When the temperature and salinity have a large influence on the analysis result, it is preferable to use a soil moisture sensor insensitive to temperature and salinity. The soil moisture content-time t change data in the wet area and at the dry-wet boundary according to the present invention are preferably embodied in the form of a time-dependent change curve of the soil moisture content in the wet area and at the dry-wet boundary. The time interval for detecting the soil moisture content needs to ensure that the soil moisture sensor has enough time resolution, and the time interval is 5 minutes in the embodiment.
After the soil moisture content-time change data in the wet area and at the dry-wet boundary of the water retention area are obtained, the invention carries out fast Fourier transform on the soil moisture content-time t change data in the wet area and at the dry-wet boundary of the water retention area to obtain the soil moisture spectrum data in the wet area and at the dry-wet boundary respectively.
In the invention, after the moisture content-time t change data at the dry-wet boundary is subjected to fast Fourier transform, a fundamental frequency caused by daily change of moisture and a high frequency and harmonic caused by water absorption of crops are generally obtained to form soil moisture spectrum data at the dry-wet boundary.
After the soil moisture spectrum data of the dry and wet boundaries are obtained, the natural frequency omega caused by the water absorption activity of plants is obtained according to the analysis of the soil moisture spectrum data of the dry and wet boundaries n 。
Obtaining the natural frequency omega n The invention then uses the natural frequency omega n And (3) analyzing the soil moisture spectrum data in the wetting area to obtain the vibration frequency caused by the water absorption activity of the plants for comparison. After the data of the change of the soil moisture content and the time t of the wetting zone is subjected to the fast Fourier transform, the data of the soil moisture spectrum in the wetting zone is matched with the natural frequency omega n The frequencies consistent with integer multiples of (1) can be determined to be caused by water uptake by plants.
After the vibration frequency is obtained, the invention preferably eliminates the fundamental frequency in the background, the direct current component and the water redistribution frequency in the vibration frequency, reserves the water absorption frequency of the plant root system and obtains the filtered soil moisture spectrum data in the wetting area.
After the filtered soil moisture spectrum data in the wetting area is obtained, the invention carries out inverse Fourier transform on the filtered soil moisture spectrum data in the wetting area, and resumes the vibration waveform caused by plant water absorption to obtain the vibration amplitude A.
Obtaining the natural frequency omega n And the oscillation amplitude A, the invention obtains the photosynthetic rate according to a preset relation I；
A relation I; wherein (1)>And->Amplitude and phase, respectively, determined by the initial waveform, are used to estimate the photosynthetic rate in a certain interval>The value may be 0.
In the present invention, it can be assumed that the boundary of the water retention area, i.e., the wetting peak is subjected to the opposite force vector-soil tension and root suction. The root suction force is mainly caused by the migration of water to the root caused by the water absorption of the root system, and photosynthesis is a main driving force; soil tension is the diffusion of water from the meniscus phenomenon at the dry/wet water boundary to the areas with lower water potential around, and is determined by irrigation negative pressure. Thus, there are push and pull forces along the normal direction of the dry/wet boundary, which are traction-constrained with each other. The wetting peak vibrates back and forth under the action of the vector sum of the pushing force and the pulling force. Assuming that the wetting peak consists of an infinite number of spring oscillators, the derivation of said relation i preferably comprises: describing moisture vibration of dry and wet boundary regions using vibration model of spring-mass system, boundary regionsForce vector sum and displacement along normal directionThe differential equation can be given by:
a relation II;
wherein,,acceleration (x/y)>Is the mass of the sprung oscillator, +.>Is the modulus of elasticity.
When (when)=/>When the equation is converted into:
a relation III;
wherein,,is natural frequency->The number of vibrations. The general solution of the equation is given by:
a relation III;
taking the first derivative of this equation and then the velocityFrom the relationship typeI is obtained.
The invention uses a negative pressure irrigation method to ensure that the boundary moisture vibration period of the water-retaining area is consistent with the plant water absorption period; analyzing the moisture vibration characteristics of the boundary of the root system water-retaining area by using a frequency analysis method; a vibration model of the spring-mass system was used to establish the relationship between the frequency of moisture vibration and the photosynthetic rate of the plant. The method for detecting the photosynthetic rate is simple to operate, is little in environmental interference, can estimate the photosynthetic rate of the plant in time, and prevents water stress of crops; meanwhile, the method can solve the problems of difficult acquisition of root system-soil moisture interaction data, high analysis cost and the like.
Based on the advantages, the invention also provides application of the photosynthetic rate detection method in water-saving irrigation. The water-saving irrigation according to the invention preferably comprises subsurface drip irrigation, further preferably comprises subsurface drip irrigation fine moisture management. When the physical stress exists as an object, the photosynthetic rate is changed, so that the management measures can be timely found and targeted adjustment and control. When the irrigation negative pressure can not meet the growth requirement of crops, the photosynthesis rate is reduced, and the irrigation negative pressure can be timely increased, so that fine moisture management is realized.
The technical solutions provided by the present invention are described in detail below with reference to the drawings and examples for further illustrating the present invention, but they should not be construed as limiting the scope of the present invention.
Example 1
A photosynthetic rate detection method based on root system-soil moisture interaction comprises the following steps, wherein a schematic diagram and a detection flow chart are respectively shown in fig. 1 and fig. 2.
The experiment is carried out in a climatic chamber, clay is fired at high temperature in soil, and the soil is put into a 110 ℃ oven for drying for 24 hours before the experiment and then is screened (1 mm). Spreading the treated soil into a cylindrical pot with the volume weight of 25 multiplied by 25cm, lightly compacting, and the volume weight of the compacted soil is about 1.0g/cm 3 . Tomato seedlings were transferred to pots after 30 days of growing in the same soil. Irrigation point sources were made of fibrous material (Toyobo, BKS 0812G) and were connected to a water supply pipe (drip irrigation pipe). Embedding point source in the middle of root area of crop to ensureThe planting points and the water supply points are consistent. Therefore, the water can be directly sent into the root zone of crops, the capillary hydraulic power is used for conveying the water into the surrounding soil, a spherical soil water-retaining area can be formed around the water source, the water source is consistent with the root system, and the spherical water-retaining area can just wrap the root zone.
Two conditions are set in the artificial climate chamber: the condition 1 (8:00-22:00) is an illumination condition, so that an indoor light source irradiates tomato seedlings to ensure photosynthesis of plants; and turning off the lamp under the condition 2 (22:00-8:00). The air temperature and maximum humidity were set to 30 ℃ and 60% under condition 1 and 22 ℃ and 60% under condition 2. Irrigation is automatically controlled by a controller, irrigation intervals are 150min (6 times a day) during the period of illumination, the water amount of each irrigation is 10mL, and liquid fertilizer (N: P: K=5:5:5, hyponex) is mixed with irrigation water in a ratio of 1:500 to serve as nutrient supply during cultivation.
Capacitive soil moisture sensors (EC-5, meter) were placed 3cm, 6cm and 12.5cm from the water source horizontal and 3cm, 6cm and 17cm from the vertical, respectively. The sensor is 8.9cm long, 1.8cm wide and 0.7cm high. Each measuring a cylindrical section of the soil volume about 3cm from the plate. The sensor is mounted perpendicular to the direction of the water flow to minimize the effect of the sensor volume. The data is recorded automatically by a data logger (EM 5b, meter) at sampling intervals of 5min. The measured value of each sensor is calibrated according to experimental soil, and the response data of each soil moisture sensor is shown in fig. 3 in 88-93 d time period after transplanting, wherein the top curve is the air temperature in the growth chamber. The next line is the soil moisture content of the plant growth and water source location. Curves H1, H2, V1 and V2 are soil moisture values at 3cm and 6cm positions from the horizontal (H1, H2) and vertical (V1, V2) directions of the water source, respectively. H1 and H2, V1 and V2 represent the moisture values of the boundary region between wet soil and dry soil. Curves H3 and V3 show measurements of dry soil 12cm horizontal and 17cm vertical from the water source, respectively.
From fig. 3, it can be derived that: each soil moisture content curve shows a periodic response synchronized with the daily settings of the growth chamber. The sensor at the water source is sensitive to the water supply and each spike represents the moisture response for each irrigation event. Assuming that the kinetic function of soil moisture is f (t), there are:
a relation IV;
wherein alpha, beta and a 0 Is a Direct Current (DC) component parameter representing the amount of accumulated moisture increase; t is time, omega n Is the vibration frequency; n is the harmonic number of the Fourier series, a n And b n Is a fourier coefficient. The present invention is primarily directed to the vibration component (AC) of moisture data, particularly in the boundary region of SWRZ, to estimate the water flow caused by crop absorption activity.
A Fast Fourier Transform (FFT) is applied to the soil moisture data to analyze the natural frequency of the vibration component parameters (AC) in the moisture data in the root-soil water system. The moisture vibration is the result of moisture infiltration, redistribution, and plant water absorption. The infiltration and redistribution process is mainly caused by each irrigation event and is irrelevant to the water absorption activity of the root system. The vibration component is subjected to frequency analysis in order to extract the frequency associated with the water-absorbing activity of the plant. The soil moisture content data is subjected to Fast Fourier Transform (FFT) to analyze the natural frequency of the moisture vibration component in the root-soil moisture system, and the soil moisture frequency spectrums after the soil moisture content of the soil moisture sensors at the water source and other positions are subjected to FFT are respectively shown in fig. 4 and 5.
From fig. 4, it can be derived that: the system exhibits a periodic response with harmonics that are multiples of the fundamental frequency. Irrigation is carried out 6 times per day in the illumination time (8:00 am-22:00), and as the migration of soil moisture is affected by the moisture infiltration process, the redistribution process and the tomato water absorption, two peaks at 5.26 and 5.85 cycles/14 h can be considered to be caused by irrigation events. Harmonic vibrations were found at 10.52 and 11.69 cycles/14 h, twice the irrigation frequency. The peak value of 11.11 cycles/14 h indicates that there is vibration outside the irrigation cycle, possibly caused by water absorption by the crop.
FIG. 5 is an FFT spectrum of moisture data for other sensor locations, where H1, H2, V1 and V2 are moisture vibrations at locations near the dry/wet soil boundary, and H3 and V3 are moisture vibrations in dry soil. V2 appeared to have a distinct peak at 5.85cycle/14h (marker). This frequency is consistent with the frequency of daily irrigation events shown in fig. 2, and is not clearly observed at other sensor locations. The soil moisture is sensitive to the crop water absorption activity, and the crop water absorption period is consistent with the irrigation period, so that the frequency is judged to be the natural frequency of crop water absorption.
The soil moisture waveform and spectrum in fig. 3 were filtered using a high pass filter, and the sampling frequency of the moisture data in the experiment was 0.00334Hz. The experiment used a butt Wo Sigao pass filter, the parameters of which were set as follows: the passband cut-off frequency (Wp), stopband start frequency (Ws), passband ripple (Rp) and minimum drive (Rs) in the stopband are set to 0.00005Hz, 0.00008Hz, 3db and 20db, respectively. The filtering process was performed using MATLAB R2018aTM software. The filter filters out the basic frequency, direct current component and irrigation frequency which are synchronous with the daily setting (0.58 cycle/14 h) of the artificial weather chamber, and keeps the frequency and harmonic wave caused by crop water absorption, and the result is shown in figure 6, wherein (a) is the soil moisture waveform filtered by the Batt Wo Sigao pass filter; (b) is the FFT spectrum of the filtered moisture data.
From fig. 6, it can be derived that: since crop photosynthesis is related to the daily change in the environment, the FFT spectrum generally exhibits a periodic response, and the natural frequency of crop water uptake is an integer multiple of the fundamental frequency. And filtering out frequency components caused by water redistribution by using a high-pass filter, and retaining the natural frequency and harmonic frequency of crop water absorption. The maximum amplitude of the vibration shown in FIG. 6 (a) was 0.4 (%), and the crop water absorption rate was estimated to be 0.9X10% by the formula I -4 （%/s）。
A relation I;
at the same time, the examples also tested the case of aperiodic irrigation. In the case of irregular irrigation, the frequency of the water source is not readily identifiable, as moisture vibration is sensitive to irrigation in SWRZ, but irrigation has less impact on the boundary area moisture transport. The experiment observes the frequencies caused by the migration of water to the root system due to the water absorption of the root system, and the frequencies correspond to the illumination frequency in the growth chamber, so that the frequencies can be judged to be caused by photosynthesis of plants. The frequency region caused by root system water absorption in the soil moisture spectrum at the water source can be judged according to the moisture frequency at the boundary, and the crop water absorption waveform can be recovered by adopting a filtering method, so that the photosynthesis rate is estimated.
Finally, it should be noted that, because the positive pressure irrigation method is adopted in this embodiment, the water absorption frequency of crops is mainly affected by the irrigation frequency, and the technical scheme of the invention proposes to use the negative pressure irrigation method, so that the water vibration main driving force at the boundary of the water-retaining area is the water absorption of crops, and therefore, the change of the water vibration frequency of soil at the dry and wet boundary reflects the change of the water absorption frequency of crops, and the irrigation negative pressure can be regulated according to the water absorption requirement of crops, thereby realizing fine water management. In natural frequency analysis of plant water absorption, after the moisture data of dry and wet boundary soil is converted into a frequency spectrum, a fundamental frequency, a high frequency and a harmonic wave are generally arranged, the high frequency is caused by crop water absorption, the fundamental frequency is caused by daily change of moisture content, and only the fundamental frequency is filtered in frequency analysis.
Although the foregoing embodiments have been described in some, but not all, embodiments of the invention, it should be understood that other embodiments may be devised in accordance with the present embodiments without departing from the spirit and scope of the invention.
Claims (9)
1. A photosynthetic rate detection method based on root system-soil moisture interaction comprises the following steps:
1) Carrying out negative pressure irrigation on plants, and estimating the size of a water-retaining area and the position of a wetting peak of the plant root system according to the negative pressure of the negative pressure irrigation;
2) Monitoring the moisture content of soil at the position of a wetting peak in the vertical direction of the water retention area and the central position of a plant root system to respectively obtain the change data of the moisture content of soil in the wetting area and at the dry-wet boundary of the water retention area and the time t;
3) Respectively performing fast Fourier transform on the soil moisture content-time t change data in the wet area and at the dry-wet boundary of the water retention area to respectively obtain soil moisture spectrum data in the wet area and at the dry-wet boundary;
4) Analyzing and obtaining the natural frequency omega caused by the water absorption activity of plants according to the soil moisture spectrum data at the dry-wet boundary n ；
Performing inverse Fourier transform on root system water absorption frequency in the soil moisture spectrum data in the wetting zone, and recovering vibration waveforms caused by plant water absorption to obtain vibration amplitude A;
5) Obtaining photosynthetic rate in a predetermined relation I；
A relation I; wherein (1)>And->Depending on the initial conditions, in estimating the photosynthetic rate of a certain interval +.>The value may be 0.
2. The photosynthetic rate detection method of claim 1 further comprising applying biochar to the soil prior to performing the negative pressure irrigation.
3. The photosynthetic rate detection method of claim 1 or 2 wherein the negative pressure irrigation is performed with drip irrigation and a drip irrigation pipe is connected to an irrigation point source; and an irrigation point source is arranged at the planting position of each plant.
4. The photosynthetic rate detection method of claim 1 wherein the method of estimating in step 1) comprises: setting irrigation amounts of different levels for irrigation point sources in soil, and observing the infiltration distance after each irrigation is finished; and drawing a relation curve of the infiltration distance and the irrigation amount, and estimating the size of the water-retaining area and the position of the wetting peak according to the relation curve.
5. The photosynthetic rate detection method of claim 1 wherein the monitoring in step 2) is performed with a soil moisture sensor; and respectively burying the soil moisture sensor into the position of a wetting peak in the vertical direction of the water retaining area and the center position of a plant root system.
6. The photosynthetic rate detection method of claim 1 wherein prior to performing step 4) the fundamental frequency in the background of the soil moisture content-time t-varying data in the wetted region and the frequency of the dc component and moisture redistribution are eliminated.
7. The photosynthetic rate detection method of any one of claims 1 to 6 for use in water-saving irrigation.
8. The use according to claim 7, wherein the water-saving irrigation comprises subsurface drip irrigation.
9. The use of claim 8, wherein the subsurface drip irrigation comprises fine moisture management of subsurface drip irrigation.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010064669A1 (en) * | 2008-12-05 | 2010-06-10 | 国立大学法人埼玉大学 | Method for evaluating healthiness of vascular plants, method for watering vascular plants, film-shaped electret sensor, and film-like ecm array |
| CN109349073A (en) * | 2018-12-18 | 2019-02-19 | 中国科学院沈阳应用生态研究所 | A kind of plant alternate irrigation simulation test device and method |
| US20190093064A1 (en) * | 2017-09-28 | 2019-03-28 | The Government Of The United States Of America, As Represented By The Secretary Of The Navy | Passive Acoustic Method of Determining Oxygen Production and Photosynthesis Rate of Algae |
| WO2020047579A1 (en) * | 2018-09-05 | 2020-03-12 | Rubicon Research Pty Ltd | Method and system for plant stress determination and irrigation based thereon |
| CN111915062A (en) * | 2020-07-08 | 2020-11-10 | 西北农林科技大学 | Greenhouse crop water demand regulation and control method with water utilization rate and photosynthetic rate coordinated |
| CN115868399A (en) * | 2022-12-30 | 2023-03-31 | 石家庄益康农科技发展有限公司 | Normal position negative pressure water-saving irrigation system |
-
2023
- 2023-07-07 CN CN202310825721.5A patent/CN116559383B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010064669A1 (en) * | 2008-12-05 | 2010-06-10 | 国立大学法人埼玉大学 | Method for evaluating healthiness of vascular plants, method for watering vascular plants, film-shaped electret sensor, and film-like ecm array |
| US20190093064A1 (en) * | 2017-09-28 | 2019-03-28 | The Government Of The United States Of America, As Represented By The Secretary Of The Navy | Passive Acoustic Method of Determining Oxygen Production and Photosynthesis Rate of Algae |
| WO2020047579A1 (en) * | 2018-09-05 | 2020-03-12 | Rubicon Research Pty Ltd | Method and system for plant stress determination and irrigation based thereon |
| CN109349073A (en) * | 2018-12-18 | 2019-02-19 | 中国科学院沈阳应用生态研究所 | A kind of plant alternate irrigation simulation test device and method |
| CN111915062A (en) * | 2020-07-08 | 2020-11-10 | 西北农林科技大学 | Greenhouse crop water demand regulation and control method with water utilization rate and photosynthetic rate coordinated |
| CN115868399A (en) * | 2022-12-30 | 2023-03-31 | 石家庄益康农科技发展有限公司 | Normal position negative pressure water-saving irrigation system |
Non-Patent Citations (6)
| Title |
|---|
| ZHENG TING 等: "Inverting the maximum carboxylation rate (V-cmax) from the sunlit leaf photosynthesis rate derived from measured light response curves at tower flux sites", AGRICULTURAL AND FORST METEOROLOGY, vol. 236, pages 48 - 66 * |
| 张佳: "番茄声发射特征规律及识别方法研究", 中国优秀硕士学位论文全文数据库农业科技辑, no. 1, pages 048 - 62 * |
| 李英年: "高寒草甸区土壤水分动态的模拟研究", 草地学报, vol. 6, no. 2, pages 77 - 83 * |
| 王相玲: "负压灌溉对土壤水分分布与油菜水分利用的影响", 中国优秀硕士学位论文全文数据库农业科技辑, no. 1, pages 047 - 230 * |
| 耿伟 等: "负压供水下盆栽大豆叶片的光合生理研究", 节水灌溉, no. 1, pages 5 - 8 * |
| 耿伟;王春艳;薛绪掌;王志敏;: "不同水分处理对豇豆光合生理特性的影响", 灌溉排水学报, no. 05, pages 72 - 74 * |
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