Vegetation irrigation control method, device, equipment, storage medium and program product

Abstract

The present application relates to a vegetation irrigation control method, device, equipment, storage medium and program product. The method comprises: during the vegetation growth season of artificial vegetation in a target area, obtaining the artificial vegetation transpiration contribution rate corresponding to the target artificial vegetation at the current growth stage, the artificial vegetation transpiration contribution rate is used to indicate the ratio of the actual transpiration amount to the potential transpiration amount of the target artificial vegetation at the current growth stage; when the artificial vegetation transpiration contribution rate is less than the natural vegetation transpiration contribution rate, determining to irrigate the target artificial vegetation and determining the target irrigation amount for irrigating the target artificial vegetation; wherein the natural vegetation transpiration contribution rate is the ratio of the actual transpiration amount to the potential transpiration amount of the target natural vegetation that grows and develops normally and grows well in the target area at the current growth stage.

Description

Technical Field

[0001] The present application relates to the field of irrigation technology, and in particular to a vegetation irrigation control method, device, electronic device, storage medium and program product. Background Art

[0002] Artificial vegetation is an important ecological safety barrier in human living areas, and irrigation is an important way to ensure the water demand of artificial vegetation. However, in areas with water shortages, the contradiction between water demand for ecological protection and water conservation is prominent. It is an inevitable requirement for high-quality regional development to ensure the ecological water demand of artificial vegetation and save water to the greatest extent. Determining the irrigation balance point between the ecological water demand of artificial vegetation and water conservation, that is, the irrigation time and amount, is a key problem.

[0003] At present, the upper and lower limits of vegetation water requirements are determined based on experience and semi-empirical formulas, and then the relevant index parameters are monitored to determine the irrigation time and amount. These methods that use the upper and lower limits of vegetation water requirements as irrigation conditions are simple and easy to operate, but can easily result in over-irrigation or under-irrigation. Alternatively, the irrigation time and amount of vegetation water requirements can be accurately calculated through vegetation water balance monitoring. This method determines irrigation more accurately, but is time-consuming, labor-intensive, and difficult to operate. Summary of the invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present application provides a vegetation irrigation control method, device, electronic device, storage medium and program product.

[0005] A first aspect of an embodiment of the present application provides a vegetation irrigation control method, the method comprising: during a vegetation growth season of artificial vegetation in a target area, obtaining an artificial vegetation transpiration contribution rate corresponding to a target artificial vegetation at a current growth stage, the artificial vegetation transpiration contribution rate being used to indicate a ratio of an actual transpiration amount to a potential transpiration amount of the target artificial vegetation at the current growth stage; when the artificial vegetation transpiration contribution rate is less than a natural vegetation transpiration contribution rate, determining to irrigate the target artificial vegetation, and determining a target irrigation amount for irrigating the target artificial vegetation; wherein the natural vegetation transpiration contribution rate is a ratio of an actual transpiration amount to a potential transpiration amount of a target natural vegetation that is growing and developing normally and in good condition in the target area at the current growth stage.

[0006] In some embodiments of the present application, obtaining the transpiration contribution rate of artificial vegetation corresponding to the target artificial vegetation in the current growth stage includes: predicting a first actual transpiration amount and a first potential transpiration amount of the target artificial vegetation when it is in the current growth stage through a pre-trained transpiration rate prediction model; and determining the ratio of the first actual transpiration amount to the first potential transpiration amount as the transpiration contribution rate of the artificial vegetation.

[0007] In some embodiments of the present application, the pre-trained transpiration rate prediction model is a Hydrus-1D model for simulating the vertical one-dimensional soil moisture movement process under vegetation conditions.

[0008] In some embodiments of the present application, the method of obtaining the transpiration contribution rate of the artificial vegetation corresponding to the target artificial vegetation in the current growth stage includes: using a heat diffusion probe method to monitor the trunk sap flow rate of the target artificial vegetation; calculating the first actual transpiration of the target artificial vegetation based on the trunk sap flow rate of the target artificial vegetation and the daily transpiration related formula of a single vegetation; collecting the first environmental parameters of the environment in which the target artificial vegetation is located through a fully automatic weather station, the first environmental parameters including: the average daily temperature at a height of 2m, soil heat flux, wind speed at a height of 2m, saturated water vapor pressure, actual water vapor pressure, slope of saturated water vapor pressure curve, dry and wet table constant, and net surface radiation; determining the first potential transpiration of the target artificial vegetation based on the first environmental parameters and the potential transpiration calculation formula; and determining the ratio of the first actual transpiration to the first potential transpiration as the transpiration contribution rate of the artificial vegetation.

[0009] In some embodiments of the present application, the method also includes: using a heat diffusion probe method to monitor the trunk sap flow rate of the target natural vegetation; calculating the second actual transpiration of the target natural vegetation based on the trunk sap flow rate of the target natural vegetation and the daily transpiration related formula of a single vegetation; collecting the second environmental parameters of the environment in which the target natural vegetation is located through a fully automatic weather station, the second environmental parameters including: the average daily temperature at a height of 2m, soil heat flux, wind speed at a height of 2m, saturated water vapor pressure, actual water vapor pressure, slope of the saturated water vapor pressure curve, dry and wet table constant, and net surface radiation; determining the second potential transpiration of the target natural vegetation based on the second environmental parameters and the potential transpiration calculation formula; determining the ratio of the second actual transpiration to the second potential transpiration as the transpiration contribution rate of the natural vegetation.

[0010] In some embodiments of the present application, the target irrigation amount for irrigating the target artificial vegetation is determined, including: obtaining single irrigation amount determination parameters, the single irrigation amount determination parameters including: soil field water holding capacity, average soil moisture content when natural vegetation reaches a stable transpiration contribution rate, vegetation root layer thickness, average soil moisture content, and average projection area of ​​vegetation crowns; based on the single irrigation amount determination parameters and the single irrigation amount calculation formula, the target irrigation amount is determined.

[0011] According to a second aspect of an embodiment of the present application, a vegetation irrigation control device is provided, the device comprising: an acquisition module, for acquiring, during a vegetation growth season of artificial vegetation in a target area, an artificial vegetation transpiration contribution rate corresponding to a target artificial vegetation at a current growth stage, the artificial vegetation transpiration contribution rate being used to indicate a ratio of an actual transpiration amount to a potential transpiration amount of the target artificial vegetation at the current growth stage; a determination module, for determining, when the artificial vegetation transpiration contribution rate is less than a natural vegetation transpiration contribution rate, that the target artificial vegetation is to be irrigated, and determining a target irrigation amount for irrigating the target artificial vegetation; wherein the natural vegetation transpiration contribution rate is a ratio of an actual transpiration amount to a potential transpiration amount of a target natural vegetation that is growing and developing normally and in good condition in the target area at the current growth stage.

[0012] In some embodiments of the present application, the acquisition module is specifically used to predict the first actual transpiration amount and the first potential transpiration amount of the target artificial vegetation when it is in the current growth stage through a pre-trained transpiration rate prediction model; and determine the ratio of the first actual transpiration amount to the first potential transpiration amount as the transpiration contribution rate of the artificial vegetation.

[0013] In some embodiments of the present application, the pre-trained transpiration rate prediction model is a Hydrus-1D model for simulating the vertical one-dimensional soil moisture movement process under vegetation conditions.

[0014] In some embodiments of the present application, the acquisition module is specifically used to monitor the trunk sap flow rate of the target artificial vegetation using a heat diffusion probe method; based on the trunk sap flow rate of the target artificial vegetation and the daily transpiration related formula of a single vegetation, calculate the first actual transpiration of the target artificial vegetation; collect the first environmental parameters of the environment in which the target artificial vegetation is located through a fully automatic weather station, the first environmental parameters including: the average daily temperature at a height of 2m, soil heat flux, wind speed at a height of 2m, saturated water vapor pressure, actual water vapor pressure, slope of the saturated water vapor pressure curve, dry and wet table constant, and net surface radiation; based on the first environmental parameters and the potential transpiration calculation formula, determine the first potential transpiration of the target artificial vegetation; and determine the ratio of the first actual transpiration to the first potential transpiration as the transpiration contribution rate of the artificial vegetation.

[0015] In some embodiments of the present application, the device also includes: a monitoring module, which is used to monitor the trunk sap flow rate of the target natural vegetation using a heat diffusion probe method; a calculation module, which is used to calculate the second actual transpiration of the target natural vegetation based on the trunk sap flow rate of the target natural vegetation and the daily transpiration related formula of a single vegetation; a collection module, which is used to collect the second environmental parameters of the environment in which the target natural vegetation is located through a fully automatic weather station, and the second environmental parameters include: the average daily temperature at a height of 2m, soil heat flux, wind speed at a height of 2m, saturated water vapor pressure, actual water vapor pressure, slope of the saturated water vapor pressure curve, dry and wet table constant, and net surface radiation; the determination module is also used to determine the second potential transpiration of the target natural vegetation based on the second environmental parameters and the potential transpiration calculation formula; the ratio of the second actual transpiration to the second potential transpiration is determined as the transpiration contribution rate of the natural vegetation.

[0016] In some embodiments of the present application, the determination module is specifically used to obtain parameters for determining a single irrigation amount, and the parameters for determining a single irrigation amount include: soil field water holding capacity, average soil moisture content when natural vegetation reaches a stable transpiration contribution rate, vegetation root layer thickness, average soil moisture content, and average projection area of ​​vegetation crowns; based on the single irrigation amount determination parameters and the single irrigation amount calculation formula, the target irrigation amount is determined.

[0017] According to a third aspect of an embodiment of the present application, an electronic device is provided, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the vegetation irrigation control method as described in the first aspect is implemented.

[0018] According to a fourth aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the vegetation irrigation control method as described in the first aspect is implemented.

[0019] A fifth aspect of an embodiment of the present application provides a computer program product, wherein the computer program product includes a computer program. When the computer program product runs on a processor, the processor executes the computer program to implement the vegetation irrigation control method as described in the first aspect.

[0020] In a sixth aspect of an embodiment of the present application, a chip is provided, which includes a processor and a communication interface, the communication interface is coupled to the processor, and the processor is used to run program instructions to implement the vegetation irrigation control method as described in the first aspect.

[0021] The technical solution provided by the embodiment of the present application has the following advantages over the prior art: during the vegetation growth season of the artificial vegetation in the target area, the artificial vegetation transpiration contribution rate corresponding to the target artificial vegetation in the current growth stage is obtained, and the artificial vegetation transpiration contribution rate is used to indicate the ratio of the actual transpiration to the potential transpiration of the target artificial vegetation in the current growth stage; when the artificial vegetation transpiration contribution rate is less than the natural vegetation transpiration contribution rate, it is determined to irrigate the target artificial vegetation, and the target irrigation amount for irrigating the target artificial vegetation is determined; wherein the natural vegetation transpiration contribution rate is the ratio of the actual transpiration to the potential transpiration of the target natural vegetation with normal growth and development and good growth in the target area at the current growth stage. In this way, the present application provides an artificial vegetation irrigation control method based on transpiration contribution rate, which can accurately determine the water irrigation time and irrigation amount of artificial vegetation by taking the natural vegetation transpiration contribution rate of the target natural vegetation with normal growth and development and good growth in the same area as a reference, which can not only meet the vegetation irrigation needs in a timely manner, but also save water, and provide a reference for regional ecological protection and high-quality development. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1 One of the flow charts of a vegetation irrigation control method provided in an embodiment of the present application;

[0025] Figure 2 A schematic diagram of a tree trunk sap flow and soil moisture monitoring device provided in an embodiment of the present application;

[0026] Figure 3 A structural block diagram of a vegetation irrigation control device provided in an embodiment of the present application;

[0027] Figure 4 A structural block diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only part of the embodiments of the present application, rather than all of the embodiments.

[0030] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0031] The electronic device in the embodiments of the present application may be a tablet computer, a laptop computer, a PDA, a vehicle-mounted electronic device, a wearable device, an ultra-mobile personal computer (UMPC), a personal computer (PC), etc.; the embodiments of the present application are not specifically limited.

[0032] The executor of the vegetation irrigation control method provided in the embodiment of the present application may be the electronic device mentioned above, or may be a functional module and / or functional entity in the electronic device that can implement the vegetation irrigation control method. The specific execution entity may be determined according to actual usage requirements, and the embodiment of the present application does not limit it.

[0033] The vegetation irrigation control method provided in the embodiment of the present application is described in detail below through specific embodiments and application scenarios in conjunction with the accompanying drawings.

[0034] like Figure 1 As shown, an embodiment of the present application provides a vegetation irrigation control method, which may include the following steps 101 to 104.

[0035] 101. During the vegetation growth season of the artificial vegetation in the target area, obtain the artificial vegetation transpiration contribution rate corresponding to the target artificial vegetation in the current growth stage.

[0036] The artificial vegetation transpiration contribution rate is used to indicate the ratio of the actual transpiration to the potential transpiration of the target artificial vegetation at the current growth stage.

[0037] Among them, the vegetation transpiration contribution rate is the ratio of the actual transpiration of vegetation to the potential transpiration, which is used to reflect the water stress of vegetation. The artificial vegetation transpiration contribution rate is the vegetation transpiration contribution rate corresponding to artificial vegetation, and the natural vegetation transpiration contribution rate is the vegetation transpiration contribution rate corresponding to natural vegetation.

[0038] Among them, the formula for vegetation transpiration contribution rate is:

[0039]

[0040] Where: γ vegetation transpiration contribution rate; t a is the start time of the growing season (d); t b is the end time of the growing season (d); ET a is the actual evapotranspiration of vegetation (mm / d); ET0 is the potential evapotranspiration of vegetation (mm / d).

[0041] Among them, the growing season refers to the period from the start time of the growing season to the end time of the growing season.

[0042] In some embodiments of the present application, the transpiration contribution rate of artificial vegetation may be the transpiration contribution rate within a preset monitoring time. The preset time may be several hours, one day, two days, etc. In order to ensure that it is possible to determine in time whether the artificial vegetation needs water, the preset time is usually not too long, and may be determined according to actual conditions, and is not limited here.

[0043] It should be noted that, in the embodiments of the present application, the preset duration is one day as an example for explanation, that is, the actual transpiration and potential transpiration of artificial vegetation, and the actual transpiration and potential transpiration of natural vegetation are all daily transpiration.

[0044] 102. When the transpiration contribution rate of the artificial vegetation is less than the transpiration contribution rate of the natural vegetation, it is determined to irrigate the target artificial vegetation.

[0045] Among them, the transpiration contribution rate of natural vegetation is the ratio of the actual transpiration and potential transpiration of the target natural vegetation with normal growth and good growth in the target area at the current growth stage.

[0046] Since the target natural vegetation grows and develops normally and grows well without irrigation, it is believed that the root water absorption and transpiration of the target natural vegetation are in a relatively optimal state. At this time, the target natural vegetation can meet its growth and actual transpiration needs through its own root water absorption. The transpiration of the target natural vegetation is used as a reference condition for whether the target artificial vegetation needs irrigation. The potential transpiration is mainly related to the meteorological factors of the region (the potential transpiration rates of vegetation (natural vegetation and artificial vegetation) in the same region are roughly the same), and the actual transpiration is related to the water absorption of the vegetation roots, meteorological conditions and the growth stage of the vegetation (the same region, the same vegetation at the same growth stage, the more water the roots absorb, the more actual transpiration). Therefore, when the artificial vegetation transpiration contribution rate of the target artificial vegetation is less than the natural vegetation transpiration contribution rate of the target natural vegetation, it means that at the same potential transpiration (calculated by the actual transpiration and the growth stage), the actual transpiration is greater than the actual transpiration. The ratio of potential transpiration is used as the vegetation transpiration contribution rate, so that the potential transpiration of the target artificial natural vegetation is at the same level as the potential transpiration of the target natural vegetation. Under the condition that the actual transpiration of the target artificial vegetation at the same growth stage is less than the actual transpiration of the target natural vegetation, and then the root water absorption of the target artificial vegetation is less than the root water absorption of the target natural vegetation, which means that the root water absorption of the target artificial vegetation is insufficient, the target artificial vegetation is seriously under water stress, and the target artificial vegetation needs to be irrigated.

[0047] 103. Determine the target irrigation amount for irrigating the target artificial vegetation.

[0048] In some embodiments of the present application, the target irrigation volume may be determined in real time or may be preset, and may be specifically determined based on actual conditions, which is not limited here.

[0049] In some embodiments of the present application, if the target irrigation amount is preset, there may be a preset corresponding relationship between the target irrigation amount and the artificial vegetation transpiration contribution rate, that is, different artificial vegetation transpiration contribution rates correspond to different target irrigation amounts; the target irrigation amount may also have a preset corresponding relationship with the vegetation contribution rate difference (the difference between the natural vegetation transpiration contribution rate and the artificial vegetation transpiration contribution rate), that is, different vegetation contribution rate differences correspond to different target irrigation amounts.

[0050] According to the natural vegetation transpiration contribution rate γ f The irrigation time and amount of artificial vegetation are determined by the single irrigation amount of vegetation W, and the irrigation of artificial vegetation is regulated. a To the end of the growing season b During this period, when γ d Below γ f When , irrigation is carried out once, and the irrigation amount is W.

[0051] The present application provides an artificial vegetation irrigation control method based on transpiration contribution rate. The method uses the natural vegetation transpiration contribution rate of the target natural vegetation with normal growth and good growth in the same area as a reference, so as to accurately determine the water requirement irrigation time and amount of artificial vegetation. It can not only meet the vegetation irrigation needs in time, but also save water, providing a reference for regional ecological protection and high-quality development.

[0052] In some embodiments of the present application, the above step 101 can be specifically implemented through the following steps 101a and 101b.

[0053] 101a. Predicting a first actual transpiration rate and a first potential transpiration rate of the target artificial vegetation when it is in the current growth stage by using a pre-trained transpiration rate prediction model.

[0054] In some embodiments of the present application, the pre-trained transpiration rate prediction model is a Hydrus-1D model for simulating the vertical one-dimensional soil moisture movement process under vegetation conditions.

[0055] The contribution rate of vegetation transpiration under different groundwater depth conditions can be obtained by simulating the vertical one-dimensional soil moisture movement process under vegetation conditions through experimental observation data and the Hydrus-1D model. The water movement process of the forest GSPAC system is simulated based on the Hydrus-1D model and experimental station observation data. The Hydrus-1D model can flexibly adjust boundary conditions and initial conditions to simulate water movement under different conditions. The main modules include root water absorption, soil water movement and vegetation evapotranspiration modules. Soil water movement is simulated based on the Richards water movement equation; the Van Genuchten equation and the Brooks-Corey equation are used to calculate soil water movement parameters; the Feddes root model and the S-Shape root model are used to simulate the plant root water absorption process. The Penman-Montheith formula and the Hargreaves formula recommended by FAO56 are used to calculate evapotranspiration. 1) Boundary conditions: The upper boundary condition is set as a given flux boundary, that is, the surface soil evaporation or rainfall / irrigation is used as the upper boundary; the lower boundary condition is set as the variable water head as the lower boundary, and the water head value is obtained by subtracting the measured groundwater depth from the bottom of the model. 2) Soil moisture characteristic parameters: A pressure membrane instrument is used to measure the soil moisture content corresponding to different pressures in each soil layer, and the soil moisture characteristic curve parameters of the Van Genuchten model are fitted using RETC software (θs uses the measured value), and finally the basic physical properties and hydraulic parameters of the sample soil are obtained. 3) Root water absorption model: Based on the experimental root digging results, a suitable root model is selected to simulate the plant root water absorption process. Based on the actual transpiration and potential actual transpiration of vegetation simulated by the model, the artificial vegetation transpiration contribution rate γ is calculated. d .

[0056] Among them, based on Richards water movement equation:

[0057]

[0058] Where: t is time (h); θ is the volumetric water content of the soil profile (cm 3 / cm 3 ) ; h is the negative pressure head of the soil profile (cm); z is the vertical spatial coordinate (cm); k(h) is the unsaturated hydraulic conductivity of the soil (cm / h); q0(0, t) is the upper boundary water flux (cm / h); h(B, t) is the lower boundary negative pressure value (cm); S(z, t) is the root water absorption rate (cm / h).

[0059] In some embodiments of the present application, the pre-trained transpiration rate prediction model may also be other models, which can be determined based on actual conditions and are not limited here.

[0060] 101b. Determine the ratio of the first actual transpiration amount to the first potential transpiration amount as the transpiration contribution rate of the artificial vegetation.

[0061] In the embodiment of the present application, the transpiration contribution rate of artificial vegetation can be determined quickly and accurately through the pre-trained transpiration rate prediction model, and the cost of determining the transpiration contribution rate of artificial vegetation can be reduced.

[0062] In some embodiments of the present application, the above step 101 can be specifically implemented through the following steps 101c to 101g.

[0063] 101c. The heat diffusion probe method is used to monitor the trunk sap flow rate of the target artificial vegetation.

[0064] 101d. Calculate the first actual transpiration of the target artificial vegetation based on the trunk sap flow rate of the target artificial vegetation and a formula related to the daily transpiration of a single plant.

[0065] 101e. Collect the first environmental parameter of the environment where the target artificial vegetation is located through a fully automatic weather station.

[0066] Among them, the first environmental parameters include: average daily temperature at 2m height, soil heat flux, wind speed at 2m height, saturated water vapor pressure, actual water vapor pressure, slope of saturated water vapor pressure curve, psychrometric constant, and net surface radiation.

[0067] 101f. Determine a first potential transpiration of the target artificial vegetation based on the first environmental parameter and a potential transpiration calculation formula.

[0068] 101g. Determine the ratio of the first actual transpiration amount to the first potential transpiration amount as the transpiration contribution rate of the artificial vegetation.

[0069] For example, the heat diffusion probe method is used to monitor the trunk sap flow rate of the target artificial vegetation, and then the transpiration of individual trees and forest stands is calculated according to the relevant formula. The relevant formula for the daily transpiration of a single plant is as follows:

[0070]

[0071] A s =π(rr b ) 2 -π(rr b -r s ) 2

[0072] F s =24×V s ×A s ×3.6

[0073]

[0074] Among them, V s is the sap flow density of a single tree (g·cm -2 ·s -1 );ΔT m is the maximum probe temperature difference within 24 hours (℃), ΔT is the instantaneous temperature difference between the two probes (℃); A s is the sapwood area (cm 2 ), r is the breast diameter (cm), r b is the bark thickness (cm), r s is the sapwood thickness (cm), measured using a growth cone to drill the core of the tree; F s is the sap flow rate of a single tree (kg·d -1 );A p The projected area of ​​the crown of a single plant (m 2 ).

[0075] An automatic weather station was installed near the artificial vegetation, and the data collection interval was set to be consistent with the frequency of tree trunk sap flow collection. Multiple first environmental parameters such as air temperature and wind speed were collected, and the first environmental parameters were substituted into the Penman-Monteith formula to calculate the potential transpiration of the artificial vegetation. The calculation formula is as follows:

[0076]

[0077] Where ET0 is the potential evaporation (mm·d -1 );T mean is the daily average temperature at 2 m above the ground (°C); G is the soil heat flux (MJ·m -2 ·d -1 ); u2 is the wind speed at a height of 2m (m·s -1);e s is the saturated water vapor pressure (kPa); e a is the actual water vapor pressure (kPa); Δ is the slope of the saturated water vapor pressure curve (kPa·℃ -1 ); γ is the psychrometric constant (kPa·℃ -1 );R n is the net radiation of the surface (MJ·m -2 ·d -1 ).

[0078] The first actual transpiration is calculated according to the above formula related to the daily transpiration of the single plant, and the first potential transpiration is calculated according to the above Penman-Monteith formula. The first actual transpiration and the first potential transpiration of the artificial vegetation are substituted into the formula of the transpiration contribution rate of the vegetation to calculate γ d .

[0079] In the embodiment of the present application, the artificial vegetation transpiration contribution rate of the target artificial vegetation can be accurately determined through the above steps 101c to 101g.

[0080] In some embodiments of the present application, before the above step 102, the vegetation irrigation control method provided in the embodiment of the present application may also include the following steps 104 to 108.

[0081] 104. The heat diffusion probe method was used to monitor the trunk sap flow rate of the target natural vegetation.

[0082] 105. Based on the trunk sap flow rate of the target natural vegetation and a formula related to the daily transpiration of a single plant, calculate a second actual transpiration of the target natural vegetation.

[0083] 106. Collect the second environmental parameter of the environment where the target natural vegetation is located through a fully automatic weather station.

[0084] Among them, the second environmental parameters include: average daily temperature at 2m height, soil heat flux, wind speed at 2m height, saturated water vapor pressure, actual water vapor pressure, slope of saturated water vapor pressure curve, dry and wet table constant, and surface net radiation.

[0085] 107. Based on the second environmental parameter and the potential transpiration calculation formula, determine the second potential transpiration of the target natural vegetation.

[0086] 108. The ratio of the second actual transpiration to the second potential transpiration is determined as the transpiration contribution rate of the natural vegetation.

[0087] Exemplarily, target natural vegetation with normal growth and good development in the target area is selected, and the trunk sap flow rate of the target natural vegetation is monitored by the thermal diffusion probe method. Then, according to the calculation formula of the daily transpiration of a single plant (as introduced above, which will not be repeated here), the second actual transpiration is calculated.

[0088] A fully automatic weather station was installed near the target natural vegetation. The data collection interval was set to be consistent with the frequency of trunk sap flow collection. Multiple second environmental parameters such as air temperature and wind speed were collected. The second environmental parameters were substituted into the Penman-Monteith formula to calculate the second potential evaporation of the target natural vegetation.

[0089] Substituting the second actual evaporation and the second potential evaporation of natural vegetation into the evaporation contribution rate formula of vegetation can calculate γ f , and this value is used as the reference standard for artificial vegetation irrigation time.

[0090] For example, Figure 2 Shown is a schematic diagram of the tree trunk sap flow and soil moisture monitoring equipment.

[0091] In the embodiment of the present application, the natural vegetation transpiration contribution rate of the target natural vegetation can be accurately determined through the above steps 104 to 108.

[0092] In some embodiments of the present application, in addition to determining the natural vegetation transpiration contribution rate of the target natural vegetation through the methods of steps 104 to 108 above, the natural vegetation transpiration contribution rate of the target natural vegetation can also be predicted by a pre-trained transpiration rate prediction model. The specific process can refer to the specific description of predicting the artificial vegetation transpiration contribution rate of the target artificial vegetation through a pre-trained transpiration rate prediction model in steps 101a and 101b above, which will not be repeated here.

[0093] In some embodiments of the present application, the above step 103 can be specifically implemented through the following steps 103a and 103b.

[0094] 103a. Obtaining single irrigation volume determination parameters.

[0095] Among them, the parameters for determining the single irrigation amount include: soil field water holding capacity, average soil moisture content when natural vegetation reaches a stable transpiration contribution rate, vegetation root layer thickness, average soil moisture content, and average projection area of ​​vegetation crowns.

[0096] 103b. Determine the target irrigation amount based on the single irrigation amount determination parameter and the single irrigation amount calculation formula.

[0097] The amount of water for a single irrigation of vegetation can be determined based on the soil field water holding capacity θ c , natural vegetation reaches a stable transpiration contribution rate γ fThe average soil moisture content at m , vegetation root layer thickness H r , average projection area of ​​vegetation crown A m Determine. The calculation formula for a single irrigation volume is:

[0098] W=(θ c -θ m )×H r ×A m .

[0099] Where W is the single irrigation amount of vegetation (m 3 );θ c is the field water holding capacity of soil (%); θ m To achieve a stable transpiration contribution rate for natural vegetationγ f Average soil moisture content at 150 °C (%); H r is the thickness of the vegetation root layer (m); A m is the average projection area of ​​vegetation crown (m 2 ).

[0100] Among them, soil field water holding capacity θ c Determination: This value reflects the amount of water retention in the soil and is selected as the boundary standard for irrigation. It can be determined by the following method: use a ring knife to collect undisturbed soil near the vegetation, place it in an enamel tray filled with water, and allow the water to saturate the soil; at the same time, collect soil from the same soil layer, air-dry it, grind it through a 1 mm sieve, and put it into the ring knife; take out the ring knife containing undisturbed soil that has been saturated with water for a day and night, open the bottom cover, and place it together with the filter paper on the ring knife containing dry soil; after 8 hours of water absorption, take out 15 to 20 grams of undisturbed soil from the ring knife to determine the water content. This value is the field water holding capacity of the soil.

[0101] Average soil moisture contentθ m :according to Figure 2 The soil moisture monitoring results of natural vegetation are shown, and the contribution rate of vegetation to stable transpiration is calculated statistically. f The soil moisture content at that time can be obtained.

[0102] Average projection area of ​​vegetation crown A m : Select three types of similar vegetation, large, medium and small, measure the diameter of the projection area of ​​the crown of each vegetation on the ground, calculate the average diameter, and then obtain it through circle area calculation.

[0103] Thickness of vegetation root layer H r :Obtained through survey sampling and literature review.

[0104] In the embodiment of the present application, the target irrigation amount can be accurately determined in real time according to the above steps 103a and 103b.

[0105] Figure 3 This is a structural block diagram of a vegetation irrigation control device shown in an embodiment of the present application, such as Figure 3 As shown, it includes: an acquisition module 301, which is used to acquire the artificial vegetation transpiration contribution rate corresponding to the target artificial vegetation at the current growth stage during the vegetation growth season of the artificial vegetation in the target area, and the artificial vegetation transpiration contribution rate is used to indicate the ratio of the actual transpiration amount to the potential transpiration amount of the target artificial vegetation at the current growth stage; a determination module 302, which is used to determine that the target artificial vegetation is irrigated and the target irrigation amount for irrigating the target artificial vegetation when the transpiration contribution rate of the artificial vegetation is less than the transpiration contribution rate of the natural vegetation; wherein the natural vegetation transpiration contribution rate is the ratio of the actual transpiration amount to the potential transpiration amount of the target natural vegetation that grows and develops normally and grows well in the target area at the current growth stage.

[0106] In some embodiments of the present application, the acquisition module 301 is specifically used to predict the first actual transpiration amount and the first potential transpiration amount of the target artificial vegetation when it is in the current growth stage through a pre-trained transpiration rate prediction model; and determine the ratio of the first actual transpiration amount to the first potential transpiration amount as the transpiration contribution rate of the artificial vegetation.

[0107] In some embodiments of the present application, the pre-trained transpiration rate prediction model is a Hydrus-1D model for simulating the vertical one-dimensional soil moisture movement process under vegetation conditions.

[0108] In some embodiments of the present application, the acquisition module 301 is specifically used to monitor the trunk sap flow rate of the target artificial vegetation using a heat diffusion probe method; calculate the first actual transpiration of the target artificial vegetation based on the trunk sap flow rate of the target artificial vegetation and the daily transpiration related formula of a single vegetation; collect the first environmental parameters of the environment in which the target artificial vegetation is located through a fully automatic weather station, the first environmental parameters including: the average daily temperature at a height of 2m, soil heat flux, wind speed at a height of 2m, saturated water vapor pressure, actual water vapor pressure, slope of saturated water vapor pressure curve, dry and wet table constant, and net surface radiation; determine the first potential transpiration of the target artificial vegetation based on the first environmental parameters and the potential transpiration calculation formula; determine the ratio of the first actual transpiration to the first potential transpiration as the transpiration contribution rate of the artificial vegetation.

[0109] In some embodiments of the present application, the device also includes: a monitoring module, which is used to monitor the trunk sap flow rate of the target natural vegetation using a heat diffusion probe method; a calculation module, which is used to calculate the second actual transpiration of the target natural vegetation based on the trunk sap flow rate of the target natural vegetation and the daily transpiration related formula of a single vegetation; a collection module, which is used to collect the second environmental parameters of the environment in which the target natural vegetation is located through a fully automatic weather station, and the second environmental parameters include: the average daily temperature at a height of 2m, soil heat flux, wind speed at a height of 2m, saturated water vapor pressure, actual water vapor pressure, slope of saturated water vapor pressure curve, dry and wet table constant, and net surface radiation; the determination module 302 is also used to determine the second potential transpiration of the target natural vegetation based on the second environmental parameters and the potential transpiration calculation formula; the ratio of the second actual transpiration to the second potential transpiration is determined as the transpiration contribution rate of the natural vegetation.

[0110] In some embodiments of the present application, the determination module 302 is specifically used to obtain parameters for determining a single irrigation amount, which include: soil field water holding capacity, average soil moisture content when natural vegetation reaches a stable transpiration contribution rate, vegetation root layer thickness, average soil moisture content, and average projection area of ​​vegetation crowns; based on the single irrigation amount determination parameters and the single irrigation amount calculation formula, the target irrigation amount is determined.

[0111] In the embodiments of the present application, each module can implement the vegetation irrigation control method provided in the above method embodiments and can achieve the same technical effect. To avoid repetition, it will not be described here.

[0112] Figure 4 The structural schematic diagram of an electronic device provided in the embodiment of the present application is used to exemplify the electronic device that implements any vegetation irrigation control method in the embodiment of the present application, and should not be understood as a specific limitation on the embodiment of the present application.

[0113] like Figure 4 As shown, the electronic device 400 may include a processor (e.g., a central processing unit, a graphics processing unit, etc.) 401, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 402 or a program loaded from a storage device 408 into a random access memory (RAM) 403. In the RAM 403, various programs and data required for the operation of the electronic device 400 are also stored. The processor 401, the ROM 402, and the RAM 403 are connected to each other via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0114] Typically, the following devices may be connected to the I / O interface 405: input devices 406 including, for example, a touch screen, a touchpad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; output devices 407 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 408 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 409. The communication device 409 may allow the electronic device 400 to communicate wirelessly or wired with other devices to exchange data. Although an electronic device 400 having various devices is shown, it should be understood that it is not required to implement or have all the devices shown. More or fewer devices may be implemented or have alternatively.

[0115] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a non-transitory computer-readable medium, and the computer program contains program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication device 409, or installed from the storage device 408, or installed from the ROM 402. When the computer program is executed by the processor 401, the functions defined in any vegetation irrigation control method provided in the embodiment of the present application can be executed.

[0116] It should be noted that the computer-readable medium mentioned above in the present application may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which a computer-readable program code is carried. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer readable signal medium may also be any computer readable medium other than a computer readable storage medium, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0117] In some embodiments, the client and the server may communicate using any currently known or future developed network protocol such as HTTP (HyperText Transfer Protocol), and may be interconnected with any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network ("LAN"), a wide area network ("WAN"), an internet (e.g., the Internet), and a peer-to-peer network (e.g., an ad hoc peer-to-peer network), as well as any currently known or future developed network.

[0118] The computer-readable medium may be included in the electronic device, or may exist independently without being incorporated into the electronic device.

[0119] The computer-readable medium carries one or more programs. When the one or more programs are executed by the electronic device, the electronic device: during the vegetation growth season of the artificial vegetation in the target area, obtains the artificial vegetation transpiration contribution rate corresponding to the target artificial vegetation in the current growth stage, and the artificial vegetation transpiration contribution rate is used to indicate the ratio of the actual transpiration amount to the potential transpiration amount of the target artificial vegetation in the current growth stage; when the artificial vegetation transpiration contribution rate is less than the natural vegetation transpiration contribution rate, determines to irrigate the target artificial vegetation, and determines the target irrigation amount for irrigating the target artificial vegetation; wherein the natural vegetation transpiration contribution rate is the ratio of the actual transpiration amount to the potential transpiration amount of the target natural vegetation that grows and develops normally and grows well in the target area in the current growth stage.

[0120] In an embodiment of the present application, a computer program code for performing the operation of the present application can be written in one or more programming languages ​​or a combination thereof, and the above-mentioned programming languages ​​include but are not limited to object-oriented programming languages, such as Java, Smalltalk, C++, and also include conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed completely on the computer, partially on the computer, as an independent software package, partially on the computer and partially on the remote computer, or completely on the remote computer or server. In the case of a remote computer, the remote computer can be connected to the computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0121] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0122] The units involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of a unit does not, in some cases, constitute a limitation on the unit itself.

[0123] The functions described above herein may be performed at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and the like.

[0124] In the context of the present application, a computer-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. A more specific example of a computer-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0125] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of disclosure involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other to form a technical solution.

[0126] In addition, although each operation is described in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or to be performed in a sequential order. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the application. Some features described in the context of a separate embodiment can also be implemented in a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable sub-combination mode.

[0127] Although the subject matter has been described in language specific to structural features and / or methodological logical actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. On the contrary, the specific features and actions described above are merely example forms of implementing the claims.

Claims

1. A vegetation irrigation control method, characterized in that: The method comprises: During the vegetation growth season of the artificial vegetation in the target area, predicting a first actual transpiration amount and a first potential transpiration amount of the target artificial vegetation at the current growth stage by using a pre-trained transpiration rate prediction model; determining the ratio of the first actual transpiration amount to the first potential transpiration amount as the transpiration contribution rate of the artificial vegetation; or During the vegetation growth season of the artificial vegetation in the target area, the trunk sap flow rate of the target artificial vegetation is monitored by a heat diffusion probe method; based on the trunk sap flow rate of the target artificial vegetation and the daily transpiration formula of a single plant, the first actual transpiration of the target artificial vegetation is calculated; the first environmental parameters of the environment in which the target artificial vegetation is located are collected through a fully automatic weather station, and the first environmental parameters include: the average daily temperature at a height of 2m, soil heat flux, wind speed at a height of 2m, saturated water vapor pressure, actual water vapor pressure, slope of saturated water vapor pressure curve, psychrometric constant, and net surface radiation; based on the first environmental parameters and the potential transpiration calculation formula, the first potential transpiration of the target artificial vegetation is determined; the ratio of the first actual transpiration to the first potential transpiration is determined as the transpiration contribution rate of the artificial vegetation; In a case where the transpiration contribution rate of the artificial vegetation is less than the transpiration contribution rate of the natural vegetation, determining to irrigate the target artificial vegetation, and determining a target irrigation amount for irrigating the target artificial vegetation; The natural vegetation transpiration contribution rate is the ratio of the actual transpiration to the potential transpiration of the target natural vegetation that is growing normally and well in the target area at the current growth stage.

2. The method according to claim 1, characterized in that The pre-trained transpiration rate prediction model is a Hydrus-1D model for simulating the vertical one-dimensional soil moisture movement process under vegetation conditions.

3. The method according to claim 1, characterized in that: The method further comprises: Using a heat diffusion probe method, monitoring the trunk sap flow rate of the target natural vegetation; Calculating a second actual transpiration of the target natural vegetation based on the trunk sap flow rate of the target natural vegetation and a formula related to the daily transpiration of a single plant; The second environmental parameters of the environment in which the target natural vegetation is located are collected by a fully automatic weather station, and the environmental parameters include: the average daily temperature at a height of 2m, soil heat flux, wind speed at a height of 2m, saturated water vapor pressure, actual water vapor pressure, slope of saturated water vapor pressure curve, dry and wet table constant, and surface net radiation; Determining a second potential transpiration of the target natural vegetation based on the environmental parameters and a potential transpiration calculation formula; The ratio of the second actual transpiration to the second potential transpiration is determined as the natural vegetation transpiration contribution rate.

4. The method according to any one of claims 1 to 3, characterized in that The step of determining a target irrigation amount for irrigating the target artificial vegetation comprises: Obtaining parameters for determining a single irrigation amount, wherein the parameters for determining a single irrigation amount include: soil field water holding capacity, average soil moisture content when natural vegetation reaches a stable transpiration contribution rate, vegetation root layer thickness, average soil moisture content, and average projection area of ​​vegetation crowns; The target irrigation amount is determined based on the single irrigation amount determination parameters and the single irrigation amount calculation formula.

5. A vegetation irrigation control device, characterized in that: include: An acquisition module is used to predict a first actual transpiration amount and a first potential transpiration amount of the target artificial vegetation at a current growth stage during the vegetation growth season of the artificial vegetation in the target area by using a pre-trained transpiration rate prediction model; determine the ratio of the first actual transpiration amount to the first potential transpiration amount as the transpiration contribution rate of the artificial vegetation; or During the vegetation growth season of the artificial vegetation in the target area, a heat diffusion probe method is used to monitor the trunk sap flow rate of the target artificial vegetation; based on the trunk sap flow rate of the target artificial vegetation and a formula related to the daily transpiration of a single plant, a first actual transpiration of the target artificial vegetation is calculated; Collecting first environmental parameters of the environment in which the target artificial vegetation is located through a fully automatic weather station, the first environmental parameters including: average daily temperature at a height of 2m, soil heat flux, wind speed at a height of 2m, saturated water vapor pressure, actual water vapor pressure, slope of saturated water vapor pressure curve, psychrometric constant, and net surface radiation; determining a first potential transpiration of the target artificial vegetation based on the first environmental parameters and a potential transpiration calculation formula; determining a ratio of the first actual transpiration to the first potential transpiration as a transpiration contribution rate of the artificial vegetation; a determination module, configured to determine, when the transpiration contribution rate of the artificial vegetation is less than the transpiration contribution rate of the natural vegetation, to irrigate the target artificial vegetation, and to determine a target irrigation amount for irrigating the target artificial vegetation; The natural vegetation transpiration contribution rate is the ratio of the actual transpiration to the potential transpiration of the target natural vegetation that is growing normally and well in the target area at the current growth stage.

6. The device according to claim 5, characterized in that The device also includes: A monitoring module, used for monitoring the trunk sap flow rate of the target natural vegetation by using a heat diffusion probe method; A calculation module, used to calculate a second actual transpiration of the target natural vegetation based on the trunk sap flow rate of the target natural vegetation and a formula related to the daily transpiration of a single plant; A collection module is used to collect the second environmental parameters of the environment in which the target natural vegetation is located through a fully automatic weather station, wherein the environmental parameters include: average daily temperature at a height of 2 m, soil heat flux, wind speed at a height of 2 m, saturated water vapor pressure, actual water vapor pressure, slope of saturated water vapor pressure curve, dry and wet table constant, and surface net radiation; The determination module is further used to determine the second potential transpiration of the target natural vegetation based on the environmental parameters and the potential transpiration calculation formula; The ratio of the second actual transpiration to the second potential transpiration is determined as the natural vegetation transpiration contribution rate.

7. The device according to any one of claims 5 or 6, characterized in that: The determination module is specifically used to obtain single irrigation amount determination parameters, and the single irrigation amount determination parameters include: soil field water holding capacity, average soil moisture content when natural vegetation reaches a stable transpiration contribution rate, vegetation root layer thickness, average soil moisture content, and average projection area of ​​vegetation crowns; The target irrigation amount is determined based on the single irrigation amount determination parameters and the single irrigation amount calculation formula.

8. An electronic device, characterized in that: include: A memory and a processor, the memory is used to store a computer program; the processor is used to execute the vegetation irrigation control method according to any one of claims 1 to 4 when calling the computer program.

9. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a processor, the vegetation irrigation control method according to any one of claims 1 to 4 is implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the vegetation irrigation control method according to any one of claims 1 to 4 is implemented.

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