Soil wilting and saturated water content measurement method and device, electronic equipment and medium

Abstract

The present application belongs to the technical field of soil wilting and saturated water content estimation, and particularly relates to a soil wilting and saturated water content estimation method and device using multi-temporal remote sensing images, an electronic device and a medium. The method comprises: establishing a water-heat balance equation of soil wilting and saturated water content and surface temperature history of each period; solving the water-heat balance equation of each period to obtain the soil wilting and saturated water content of each period; and estimating the soil wilting and saturated water content according to the soil wilting and saturated water content of each period. The present application proposes a water-heat balance method of the physical connection among bare soil evaporation, surface temperature and soil wilting and saturated water content, which can estimate the regional soil wilting and saturated water content under a given confidence level, avoids the time-consuming and laborious shortcomings of the traditional experimental method, improves the determination efficiency of the soil wilting and saturated water content, and provides technical support for hydrological research, agricultural production, water-saving irrigation, drought monitoring, ecological restoration and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of soil wilting and saturated water content estimation, and particularly relates to a soil wilting and saturated water content estimation method and device using multi-temporal remote sensing images, an electronic device and a medium. BACKGROUND

[0002] Soil saturated water content reflects the soil pore condition and maximum water holding capacity. Grasping the spatial distribution of soil saturated water content can understand the water storage characteristics and drainage properties of soil, which is an important indicator for calculating soil column water content, soil surface runoff, soil evaporation, and the fluctuation of groundwater level caused by irrigation, drainage, pumping and precipitation, and soil water yield. Soil wilting water content is the soil water content when the soil load vegetation begins to wilt and cannot recover, which is the minimum amount of soil water to maintain the survival of soil vegetation. It is affected by soil type, soil texture and soil salinity, and is of great significance to agricultural production, ecological system water demand and soil improvement. It is an important soil water parameter.

[0003] Soil wilting and saturated water content is usually obtained through experiments. Among them, soil wilting water content generally adopts biological method, that is, plants are cultivated in a container soil, and when the plants begin to wilt due to water shortage, the soil water content of the container is measured. Soil saturated water content is usually directly measured, that is, the field original soil is placed in a closed container, and water is slowly added to the soil until the soil is saturated, and then the soil water content of the container is measured. Although laboratory determination of soil wilting and saturated water content can obtain relatively accurate values, it also has limitations. First, the laboratory determination process is complex, requires high operation skill of the experimenter, and is time-consuming and laborious. Second, the composition of field soil is complex and the structure is not the same, and the spatial representativeness of the determination results of the limited soil used in the laboratory is insufficient. Third, field soil is diverse, which leads to strong spatial heterogeneity of soil wilting and saturated water content. Obviously, it is not realistic to conduct laboratory determination on all soil samples.

[0004] However, flood forecasting in the current water cycle process, drought monitoring in agricultural production, and water consumption management in ecological restoration engineering all require regional scale soil wilting and saturated water content distribution, so it is urgent to develop a regional scale soil wilting and saturated water content rapid monitoring method. Soil evaporation is closely related to soil wilting and saturated water content, and is often parameterized in water cycle simulation based on water balance. In addition, remote sensing models for estimating land surface evapotranspiration have developed rapidly, and various land surface evapotranspiration remote sensing products have been introduced. Therefore, the present application attempts to establish a physical model of the relationship between remote sensing signals, soil evaporation and soil wilting and saturated water content, in order to realize rapid estimation of regional scale soil wilting and saturated water content. SUMMARY

[0005] The present application aims to provide a soil wilting and saturation water content calculation method, device, electronic equipment and medium, so as to overcome or partially overcome the shortcomings of the prior art.

[0006] To achieve the above technical purpose, the technical scheme adopted by the present application is:

[0007] In a first aspect, the present application provides a soil wilting and saturation water content calculation method, comprising the following steps:

[0008] S1: establishing a water-heat balance equation of soil wilting and saturation water content and ground surface temperature history in each period;

[0009] S2: solving the water-heat balance equation in each historical period to obtain the soil wilting and saturation water content in each historical period;

[0010] S3: estimating the soil saturation water content according to the soil saturation water content in each historical period;

[0011] S4: estimating the soil wilting water content according to the soil wilting water content in each historical period.

[0012] In one embodiment, the S1: establishing a water-heat balance equation of soil wilting and saturation water content and ground surface temperature history in each period, specifically:

[0013]

[0014] In the formula, 1≤n i ≤N i , the subscript i represents the i th period in each historical period, N i represents the number of time phases in the i th period, represents the soil water content (m i / m 3 ) in the n 3 time phase of the i th period, and represent the soil saturation water content (m 3 / m 3 ) and wilting water content (m 3 / m 3 ) in the i th period, represents the minimum value of the ground bare land temperature (K) in the n i time phase of the i th period, represents the maximum value of the ground bare land temperature (K) in the n i time phase of the i th period, represents the air temperature (K) in the n i time phase of the i th period, represents the ground bare land temperature (K) in the n i time phase of the i th period, represents the i-th period n i Net radiation flux of bare ground at the time phase (W / m 2 ), represents the i-th period n i Soil heat flux of bare ground at the time phase (W / m 2 ), represents the i-th period n i Potential evaporation of bare land on the surface during the phase (W / m 2 ), represents the i-th period n i Aerodynamic impedance during the phase (s / m), C A Indicates the volumetric heat capacity of air (J / (K·m 3 )), represents the i-th period n i Saturated water vapor pressure at the time of phase At air temperature The slope at represents the i-th period n i The saturation deficit of the actual water vapor pressure during the phase.

[0015] In one embodiment, the step S2: solving the water-heat balance equation for each historical period to obtain the soil wilting and saturated water content for each historical period is specifically:

[0016]

[0017] Where, and represent the soil saturated moisture content and wilting moisture content in the i-th period respectively.

[0018] In one embodiment, the step S3: estimating the soil saturated moisture content based on the soil saturated moisture content of each historical period is specifically as follows:

[0019]

[0020] Where I represents the number of historical periods, Indicates the saturated soil moisture content in a historical period The mean of S Indicates the saturated soil moisture content in a historical period The standard deviation, S S Represents the saturated water content of soil in I historical period The maximum standard deviation of the soil saturated water content estimated by mathematical statistics, t α / 2(I-1) represents the quantile of the t-distribution with a sample size of I at a given confidence level of 1-α. Since the saturated soil moisture content represents the maximum water holding capacity of the soil when all soil pores are filled with water, the estimated value range on the right side of the saturated soil moisture content is used to estimate the saturated soil moisture content.

[0021] In one embodiment, the step S4: estimating the soil wilting moisture content based on the soil wilting moisture content of each historical period is specifically:

[0022]

[0023] Where, Indicates the soil wilting water content in a historical period The mean of W Indicates the soil wilting water content in a historical period The standard deviation, S W Represents the soil wilting water content in I historical period The maximum standard deviation of the soil wilting moisture content estimated by mathematical statistics for the sample is used. Since the soil wilting moisture content represents the lower limit of the moisture content retained in the soil when the plant wilts and cannot recover, the soil wilting moisture content is estimated using the estimated value range on the left side of the soil wilting moisture content.

[0024] In a second aspect, an embodiment of the present invention provides a soil wilting and saturated moisture content measurement device, which is used to execute the soil wilting and saturated moisture content measurement method described in the first aspect, comprising: a balance module, a solution module, a saturation module, and a wilting module;

[0025] The balance module is used to execute the establishment of the water and heat balance equations of soil wilting and saturated water content and surface temperature in each historical period as described in the first aspect above;

[0026] The solution module is used to execute the solution of the water-heat balance equation of each historical period as described in the first aspect above to obtain the soil wilting and saturated water content of each historical period;

[0027] The saturation module is used to perform the estimation of soil saturated moisture content based on the soil saturated moisture content of each historical period as described in the first aspect above;

[0028] The wilting module is used to execute the estimation of soil wilting moisture content based on soil wilting moisture content in various historical periods as described in the first aspect.

[0029] In a third aspect, an embodiment of the present invention provides an electronic device for measuring soil wilting and saturated moisture content, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program stored in the memory, it implements the steps of the soil wilting and saturated moisture content measurement method described in the first aspect.

[0030] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium for soil wilting and saturated moisture content calculation, on which a computer program is stored. When the computer program is executed by a processor, the steps of the soil wilting and saturated moisture content calculation method described in the first aspect are implemented.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1) A physical equation linking bare soil evaporation, surface temperature, soil wilting, and saturated water content was proposed, laying the foundation for the measurement of soil wilting and saturated water content at the regional scale;

[0033] 2) A multi-period water-heat balance equation was established between soil water-heat fluxes based on remotely sensed surface temperature and soil evaporation fluxes based on bare soil moisture, which can be used to directly solve soil wilting and saturation water content.

[0034] 3) Taking into account the model errors of the physical equations, the ranges of soil wilting and saturated water content were accurately estimated using a multi-period estimation sample.

[0035] 4) Soil wilting and saturated water content can be estimated at a given confidence level, avoiding the time-consuming and labor-intensive shortcomings of traditional experimental determination methods and improving the efficiency of soil wilting and saturated water content determination;

[0036] 5) It broadened the physical measurement methods of soil wilting and saturated moisture content and deepened the understanding of non-contact measurement of soil wilting and saturated moisture content. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic flow chart of a method for calculating soil wilting and saturated water content provided by an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of a process flow of a soil wilting and saturated moisture content measuring device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In one embodiment, Figure 1 As shown, Figure 1 A flow chart of a method for calculating soil wilting and saturated moisture content provided by an embodiment of the present invention includes the following steps:

[0040] S1: Establish the water and heat balance equations for each period of soil wilting and saturated water content and surface temperature history;

[0041] S2: Solve the water and heat balance equations for each historical period to obtain the soil wilting and saturated water content for each historical period;

[0042] S3: estimating the soil saturated water content according to the historical soil saturated water content of each period;

[0043] S4: estimating the soil wilting water content according to the historical soil wilting water content of each period.

[0044] Based on the above embodiments, further, as shown in the following Figure 1 S1: establishing a water-heat balance equation of the soil wilting and saturated water content and the ground surface temperature of each historical period, one implementation is specifically as follows:

[0045]

[0046]

[0047] In the formula, 1≤n i ≤N i , the subscript i represents the i-th period in the historical periods, N i represents the number of time phases of the i-th period, represents the soil water content (m i / m 3 ) of the n 3 -th time phase of the i-th period, and respectively represent the soil saturated water content and the wilting water content (m 3 / m 3 ) of the i-th period, represents the minimum value of the ground bare land temperature (K) at the n i -th time phase of the i-th period, represents the maximum value of the ground bare land temperature (K) at the n i -th time phase of the i-th period, represents the air temperature (K) at the n i -th time phase of the i-th period, represents the ground bare land temperature (K) at the n i -th time phase of the i-th period, represents the net radiation flux (W / m i ) of the ground bare land at the n 2 -th time phase of the i-th period, represents the soil heat flux (W / m i ) of the ground bare land at the n 2 -th time phase of the i-th period, represents the potential evaporation (W / m i ) of the ground bare land at the n 2 -th time phase of the i-th period, represents the air dynamic resistance (s / m) at the n i -th time phase of the i-th period, C A represents the volumetric heat capacity of air (J / (K·m 3)), represents the i-th period n i Saturated water vapor pressure at the time of phase At air temperature The slope at represents the i-th period n i The saturation deficit of the actual water vapor pressure during the phase; Based on the i-th period n i The meteorological data of the time phase are calculated with reference to the relevant algorithms;

[0048] In the land surface process model, surface evapotranspiration is divided into canopy interception evaporation, bare soil evaporation, and vegetation transpiration. When there is no canopy interception evaporation in clear skies, bare soil evaporation is directly related to the surface soil moisture content, while vegetation transpiration is closely related to the root zone soil moisture. The Noah LSM, a land surface process model already in operation by agencies such as the U.S. Atmospheric and Oceanic Administration, can simulate surface water, carbon, heat, and radiation processes, and has comprehensive water balance and heat balance simulation capabilities. In the Noah LSM, evaporation from the bare soil portion of the surface is defined as the product of potential evaporation and a limiting factor. The limiting factor is a quadratic equation of surface soil moisture, soil wilting, and saturated water content, specifically:

[0049]

[0050] Where, E S Indicates bare soil evaporation (W / m 2 ), Θ represents the soil moisture of the bare soil part, Θ S and Θ W Represents soil saturated water content (m 3 / m 3 ) and wilting water content (m 3 / m 3 ), E P Indicates potential evaporation (W / m 2 );

[0051] Remote sensing evapotranspiration models have developed rapidly in recent years, with the emergence of numerous surface evapotranspiration inversion models. The feature space method is a widely used approach, achieving excellent inversion results. The feature space method uses the scatter space of vegetation index and surface temperature, and vegetation index and albedo, to obtain the dry and wet edges corresponding to zero and maximum sensible heat to calculate the evaporation ratio or Bowen ratio and estimate evapotranspiration pixel by pixel. Based on the feature space method, the calculation formula for bare soil evaporation can be derived as follows:

[0052]

[0053] Where, E S Indicates bare soil evaporation (W / m 2 ), T LIndicates the lowest value of the bare ground surface temperature (K), T H Indicates the maximum value of the bare ground surface temperature (K), T S Indicates the bare soil temperature in the surface temperature (K), R ns The net radiation of bare soil in the net radiation of the surface (W / m 2 ), G represents the soil heat flux of the bare soil part on the surface (W / m 2 );

[0054] Thus, the calculation formula of soil wilting and saturated water content can be obtained, which is:

[0055]

[0056] Take the square root of both sides of the above equation and move the terms to get:

[0057]

[0058] Considering that soil wilting and saturated water content are constant soil moisture parameters, multi-period remote sensing evapotranspiration is used to estimate soil wilting and saturated water content, which can be obtained:

[0059]

[0060] Wherein, each period can be selected as a period of time, illustratively, a period of time can be selected as one year, the number of remote sensing images of clear and cloudless skies in one year is the number of phases in that year, and multiple periods are multiple years, illustratively, can be selected as ten years, but is not limited thereto; the remote sensing data used to estimate surface evapotranspiration can be selected from the Landsat program, which is the longest-running Earth observation program, starting from July 23, 1972 to the present, and the data is open source; wherein, Landsat 8 started from February 11, 2013 to the present, the surface temperature of each phase can be obtained by inverting the thermal infrared band 10 of the Landsat 8 image of each phase through a single-channel algorithm, and the band has a spatial resolution of 100 meters and a regression period of 16 days. The surface albedo of each phase can be obtained by the reflectivity of bands 2, 4, 5, 6, and 7 of the Landsat 8 image of each phase through a weighted algorithm, and these bands have a spatial resolution of 30 meters. The single-channel algorithm and the weighted algorithm can be referred to in relevant literature;

[0061] The surface emissivity at each time phase can be obtained by spatiotemporal fusion of the ASTER GEDv3 product and the MOD11A1 product. The ASTER GEDv3 product has a spatial resolution of 100 m and global coverage, and is the average of the clear-sky surface emissivity from 2000 to 2008. The MOD11A1 product has a daily 1 km global coverage. Both products are available free of charge on the Internet. Specifically:

[0062]

[0063] wherein, denotes the surface albedo of the i-th period n i the surface albedo of the i-th period n denotes the surface albedo of the i-th period n i the surface albedo of the i-th period n denotes the mean surface albedo of the MOD11A1 product between 2000-2008, ε A denotes the surface albedo of the ASTER GED v3 product;

[0064] wherein, the vegetation fraction of each time phase can be calculated by the reflectance of the 5th near-infrared band and the 4th red band of the Landsat 8 image, specifically:

[0065]

[0066] wherein, denotes the surface albedo of the i-th period n i the surface albedo of the i-th period n denotes the surface albedo of the i-th period n i the vegetation index of the i-th period n and denotes the vegetation index of the i-th period n i the minimum and maximum values of the vegetation index of the i-th period n denotes the vegetation fraction of the i-th period n i the vegetation fraction of the i-th period n

[0067] wherein, the meteorological data can be selected as the ECMWF ERA5-Land hourly dataset, which has a time span of 1959-present, global coverage, and a spatial resolution of 0.1 degrees, and can provide hourly 2-meter air temperature, air relative humidity, 2-meter dew point temperature, 10-meter horizontal wind component, 10-meter vertical wind component, boundary layer height, 0-7cm soil volume water content, etc.

[0068] wherein, can be calculated by the bare soil temperature, bare soil albedo and bare soil albedo of the i-th period n i the bare soil temperature of the i-th period n

[0069]

[0070] wherein, denotes the surface albedo of the i-th period n i the surface temperature of the i-th period n denotes the surface albedo of the i-th period n​i The rate of change of the diurnal land surface temperature with vegetation cover can be calculated by the following formula:

[0071]

[0072] In the formula, N represents the number of pixels in the study area, represents the n i The diurnal mean vegetation cover of the study area, represents the n i The diurnal mean land surface temperature of the study area;

[0073] In the formula, represents the n i The diurnal land surface albedo of the study area can be calculated by the following formula:

[0074]

[0075] In the formula, represents the n i The diurnal mean land surface albedo of the study area;

[0076] The formula for calculating the albedo of bare soil is as follows:

[0077]

[0078] In the formula, represents the n i The diurnal land surface albedo of the study area calculated from the reflectance of the 2nd, 4th, 5th, 6th, and 7th bands of the Landsat 8 image, represents the n i The diurnal mean land surface albedo of the study area, represents the n i The diurnal land surface albedo of bare soil;

[0079] Then The formula for calculating is as follows:

[0080]

[0081] In the formula, represents the n i The diurnal incoming shortwave radiation (W / m 2 ), represents the n i The diurnal sky temperature (K), represents the n i The diurnal sky albedo can be calculated from the air temperature and the actual water vapor pressure, and σ represents the Stefan-Boltzmann constant;

[0082] Soil moisture products can be spatially downscaled using machine learning methods to obtain a spatial resolution that matches the thermal infrared band 10 of the Landsat 8 image. For example, the machine learning method can be selected as random forest, the dependent variable is the 0.1-degree ERA5-Land 0-7 cm soil moisture product, and the independent variables can be selected as albedo, surface temperature, reflectivity of each band, vegetation cover, etc. that have been spatially aggregated and upscaled to 0.1 degrees. The random forest is trained using these data, and then the albedo, surface temperature, reflectivity of each band, vegetation cover, etc. at a spatial resolution of 100 meters are input into the trained random forest model to obtain a soil moisture product at a spatial resolution of 100 meters. Assuming that the soil moisture at a spatial resolution of 100 meters is the weighted sum of bare soil moisture and root zone moisture according to vegetation cover, the bare soil moisture is calculated as follows:

[0083]

[0084] Where, represents the i-th period n i Soil moisture at a spatial resolution of 100 meters, represents the i-th period n i Phase study area The mean of .

[0085] Based on the above embodiment, further, Figure 1 As shown, the S2: solving the water and heat balance equation of each historical period to obtain the soil wilting and saturated water content of each historical period, one implementation method is as follows:

[0086]

[0087] Where, and represent the soil saturated moisture content and wilting moisture content in the i-th period respectively.

[0088] Based on the above embodiment, further, Figure 1 As shown, the S3: estimating the soil saturated moisture content based on the soil saturated moisture content of each historical period, one implementation method is as follows:

[0089]

[0090] Where I represents the number of historical periods, Indicates the saturated soil moisture content in a historical period The mean of S Indicates the saturated soil moisture content in a historical period The standard deviation, S S Represents the saturated water content of soil in I historical period The maximum standard deviation of the soil saturated water content estimated by mathematical statistics, t α / 2 (I-1) represents the quantile of the t-distribution with a given confidence level of 1-α and a sample size of I. Since the saturated soil moisture content represents the maximum water holding capacity of the soil when all soil pores are filled with water, the estimated value range on the right side of the saturated soil moisture content is used to estimate the saturated soil moisture content.

[0091] Based on the above embodiment, further, Figure 1 As shown, the S4: estimating the soil wilting moisture content based on the soil wilting moisture content of each historical period, one implementation method is as follows:

[0092]

[0093] Where, Indicates the soil wilting water content in a historical period The mean of W Indicates the soil wilting water content in a historical period The standard deviation, S W Represents the soil wilting water content in I historical period The maximum standard deviation of the soil wilting moisture content estimated by mathematical statistics for the sample is used. Since the soil wilting moisture content represents the lower limit of the moisture content retained in the soil when the plant wilts and cannot recover, the soil wilting moisture content is estimated using the estimated value range on the left side of the soil wilting moisture content.

[0094] In summary, soil wilting and saturated water content can be measured.

[0095] In one embodiment, Figure 2 As shown, a soil wilting and saturated water content measuring device is provided, which is used to execute a soil wilting and saturated water content measuring method described in the above embodiment, comprising: a balance module 1, a solution module 2, a saturation module 3, and a wilting module 4;

[0096] The balance module 1 is used to execute the water-heat balance equations for each historical period of soil wilting and saturated water content and surface temperature as described in the above embodiment;

[0097] The solving module 2 is used to solve the water-heat balance equation of each historical period as described in the above embodiment to obtain the soil wilting and saturated water content of each historical period;

[0098] The saturation module 3 is used to execute the above embodiment to estimate the soil saturated moisture content based on the soil saturated moisture content of each historical period;

[0099] The wilting module 4 is used to execute the above embodiment to estimate the soil wilting moisture content based on the soil wilting moisture content of each historical period.

[0100] The embodiment of the present application provides a soil wilting and saturation water content measuring electronic device, including: a memory and a processor, the memory stores a computer program, and when the processor executes the computer program stored by the memory, the soil wilting and saturation water content measuring method provided by the embodiment of the present application can be realized Figure 1 The technical solutions of any of the method embodiments are similar in principle and technical effects, and details are not repeated here.

[0101] The present application also provides a soil wilting and saturation water content measuring computer readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the soil wilting and saturation water content measuring method provided by the embodiment of the present application can be realized Figure 1 The technical solutions of any of the method embodiments are similar in principle and technical effects, and details are not repeated here.

[0102] Compared with the prior art, the present application has the following advantages:

[0103] 1) A new technology for non-contact measurement of soil wilting and saturation water content using remote sensing technology is proposed, which deepens the application depth of remote sensing technology for retrieving soil water parameters;

[0104] 2) A parameterization scheme for bare soil evaporation-surface temperature-soil water parameters wilting and saturation water content is constructed, and a technology for solving soil wilting and saturation water content using surface temperature is developed;

[0105] 3) In the solving process, the error of the constructed physical model in measuring soil wilting and saturation water content is fully considered, and the change interval of soil wilting and saturation water content is statistically calculated using a limited estimation sample of soil wilting and saturation water content;

[0106] 4) It can be used to judge the confidence interval of given soil wilting and saturation water content, and compared with the traditional method, the measurement efficiency of soil wilting and saturation water content is greatly improved;

[0107] 5) It can provide technical support for flood forecasting, drought monitoring in agricultural production, and soil wilting and saturation water content measurement in ecological restoration engineering.

[0108] The implementation process and technical effects of the embodiments of the soil wilting and saturation water content measuring device, electronic device and medium are the same as those of the method embodiments. For the same places, please refer to the corresponding places of the method embodiments. Based on the embodiments of the present application, ordinary skilled in the art can obtain other embodiments without creative labor, and can improve, adjust and modify the present application, or equivalently replace part of the steps of the present application, but these are within the protection scope of the present application.

Claims

1. A method for calculating soil wilting and saturated water content, characterized in that: The steps include: S1: Establish the water and heat balance equations for each period of soil wilting and saturated water content and surface temperature history, specifically: Where 1≤n i ≤N i , the subscript i represents the i-th period in each historical period, N i represents the phase number of period i, represents period i n i Soil water content of the phase (m 3 / m 3 ), and are the saturated soil water content (m 3 / m 3 ) and wilting water content (m 3 / m 3 ), represents the i-th period n i The lowest value of bare ground temperature during the phase (K), represents the i-th period n i The maximum value of bare ground temperature during the phase (K), represents the i-th period n i Air temperature at the time phase (K), represents the i-th period n i The surface temperature of the bare ground at the time of the phase (K), represents the i-th period n i Net radiation flux of bare ground at the time phase (W / m 2 ), represents the i-th period n i Soil heat flux of bare ground at the time phase (W / m 2 ), represents the i-th period n i Potential evaporation of bare land on the surface during the phase (W / m 2 ), represents the i-th period n i Aerodynamic impedance during the phase (s / m), C A Indicates the volumetric heat capacity of air (J / (K·m 3 )), represents the i-th period n i Saturated water vapor pressure at the time phase At air temperature The slope at represents the i-th period n i The saturation deficit of the actual water vapor pressure during the phase; S2: Solve the water and heat balance equations for each historical period to obtain the soil wilting and saturated water content for each historical period; S3: Estimate soil saturated water content based on soil saturated water content in each historical period; S4: Estimate soil wilting moisture content based on soil wilting moisture content in various historical periods.

2. The method according to claim 1, characterized in that Said S2 is specifically: Where, and represent the soil saturated moisture content and wilting moisture content in the i-th period respectively.

3. The method according to claim 1, characterized in that The S3 is specifically: Where I represents the number of historical periods, Indicates the saturated soil moisture content in a historical period The mean of S Indicates the saturated soil moisture content in a historical period The standard deviation, S S Represents the saturated water content of soil in I historical period The maximum standard deviation of the soil saturated water content estimated by mathematical statistics, t α / 2 (I-1) represents the quantile of the t-distribution with a given confidence level of 1-α and a sample size of I. Since the saturated soil moisture content represents the maximum water holding capacity of the soil when all soil pores are filled with water, the estimated value range on the right side of the saturated soil moisture content is used to estimate the saturated soil moisture content.

4. The method according to claim 1, wherein Said S4 is specifically: Where, Indicates the soil wilting water content in a historical period The mean of W Indicates the soil wilting water content in a historical period The standard deviation, S W Represents the soil wilting water content in I historical period The maximum standard deviation of the soil wilting moisture content estimated by mathematical statistics for the sample is used. Since the soil wilting moisture content represents the lower limit of the moisture content retained in the soil when the plant wilts and cannot recover, the soil wilting moisture content is estimated using the estimated value range on the left side of the soil wilting moisture content.

5. A soil wilting and saturated water content measuring device, characterized in that: include: Balance module, solution module, saturation module, and wilting module; The balancing module is configured to execute S1 in claim 1; The solution module is used to execute S2 in claim 2; The saturation module is used to execute S3 in claim 3; The wilting module is used to execute S4 in claim 4.

6. An electronic device for measuring soil wilting and saturated water content, comprising a memory and a processor, characterized in that: The memory stores a computer program, and when the processor executes the computer program stored in the memory, the steps of the soil wilting and saturated moisture content calculation method according to any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium for calculating soil wilting and saturated water content, having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the soil wilting and saturated moisture content calculation method according to any one of claims 1 to 4 are implemented.

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