Accurate irrigation decision-making method and system based on crop growth model and weather forecast

Abstract

The invention discloses a precise irrigation decision-making method and system based on a crop growth model and weather forecast, and relates to the field of agricultural irrigation automation control. The method comprises the following steps: calculating reference crop evapotranspiration corresponding to each growth period of crops in an irrigation decision-making area by adopting an FAO56PM formula according to meteorological data, and calculating a theoretical growth period water demand and a water demand proportion of an ith growth period in a whole growth period according to a growth period crop coefficient; the optimal growth period water demand of the crops in the whole growth period in the typical hydrological year is calculated through optimization of a crop growth model, the daily precipitation serves as a reference value of the effective precipitation, the effective precipitation is estimated according to weather forecast, and by comparing the quantitative relation between the effective precipitation and the optimal water demand of the ith growth period, the optimal growth period water demand of the crops in the ith growth period is calculated. Judging whether the irrigation decision-making area needs to be irrigated or not, and when the irrigation decision-making area needs to be irrigated, calculating and determining the optimal irrigation amount of the crops in the irrigation decision-making area in the ith growth period according to a formula.

Description

Technical Field

[0001] The present invention relates to the field of agricultural irrigation automation control, and in particular to a precise irrigation decision-making method and system based on a crop growth model and weather forecast. Background Art

[0002] Water shortage is a common problem faced by all countries in the world. Agricultural water consumption in my country accounts for about 80% of the total water consumption, and the current water utilization rate for agricultural irrigation is only 45%. In order to improve the problem of water shortage and low utilization rate, the automatic irrigation system came into being.

[0003] During the growth cycle of crops, their water requirements are not only affected by many factors such as crop type, growth period, precipitation, temperature, soil moisture, light intensity, etc., but also due to the uncertainty and complexity of each influencing factor, it is extremely difficult to predict crop water requirements. How to accurately estimate crop water requirements and dynamically generate irrigation decisions based on crop water requirements is the key to rationally utilizing water resources and improving irrigation efficiency. The current automated irrigation system focuses on collecting environmental parameters and implementing automated sprinkler irrigation based on fixed strategies based on the collected environmental parameters, or guiding automated intelligent irrigation of crops based on expert systems based on historical irrigation data. However, the above methods are less targeted and accurate, and cannot be used for precise irrigation according to the actual water requirements of crops, resulting in limited improvement in water resource utilization. To this end, we propose a precise irrigation decision-making method and system based on crop growth models and weather forecasts. Summary of the invention

[0004] The main purpose of the present invention is to provide a precise irrigation decision-making method and system based on crop growth models and weather forecasts, which can effectively solve the problems in the background technology.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] Precision irrigation decision-making methods based on crop growth models and weather forecasts, including:

[0007] According to the meteorological data, the reference crop evapotranspiration ET corresponding to each growth period of crops in the irrigation decision area is calculated using the FAO56PM formula 0 The theoretical water requirement W of the i-th growth period in the whole growth period is calculated by the reference crop evapotranspiration and the growth period crop coefficient Kc. i and the proportion of water demand β i , where W i =Kc×ET 0 ; n is the total number of reproductive periods;

[0008] The crop growth model is used to optimize and calculate the optimal water requirement W of crops during the entire growth period in a typical hydrological year. The calculation formula is: W = K 1 ×(K 2 -K 3 GDD max ), where GDD max is the maximum effective accumulated temperature during the growth period / ℃; K 1 , K 2 , K 3 are coupling constant coefficients;

[0009] Among them, the optimization process of the optimal water requirement W during the growth period is as follows:

[0010] The crop yield is calculated based on the evolution formula of the yield-water response relationship in the AquaCrop model, where the expression of the evolution formula is as follows:

[0011] B=WP×∑Tr (1)

[0012] Y=B×HI (2)

[0013]

[0014] Where B is the aboveground biomass, kg·m -2 ; WP is water productivity / kg·m -2 mm -1 ; WP * is the correction value of WP; Tr is the actual transpiration / mm; Y is the crop yield / kg·m -2 ; HI is the crop harvest index / %; For the CO 2 Concentration;

[0015] According to the meteorological data in the irrigation decision area, the relationship between crop yield, water requirement during the growth period and the maximum effective accumulated temperature during the growth period is fitted using the water-heat coupling function. The specific expression is as follows:

[0016] Y=K 4 -K 5 GDD max -K 2 W+K 6 W 2 +K 7 GDD max 2 +K 3 WGDD max (4)

[0017] In the formula, K 4 , K 5 , K 6, K 7 are coupling constant coefficients;

[0018] By taking the derivative of both sides of the above formula (4), and setting The calculation formula for the optimal water requirement W during the growth period can be obtained: W = K 1 ×(K 2 -K 3 GDD max );

[0019] Daily precipitation P day As a reference value of effective precipitation P, the effective precipitation is estimated according to the weather forecast, where P = Ua × P day , Ua is the precipitation utilization coefficient, by comparing the effective precipitation P with the optimal water requirement β of the i-th growth period i ×W quantitative relationship, determine whether it is necessary to irrigate the irrigation decision area;

[0020] When the irrigation decision area needs to be irrigated, the optimal irrigation amount I of the crops in the irrigation decision area in the i-th growth period is determined according to the calculation result of the following formula: i , the calculation formula is: i =β i ×WP-θ tc -Wk, where θ tc Field water holding capacity / m 3 / m 3 , and θ tc =0.65θ s ,θ s is the field saturated water content / m 3 / m 3 ; γ rz Soil bulk density / Kg / m 3 ; Wk is the groundwater recharge.

[0021] The calculation formula of reference crop evapotranspiration ET0 is:

[0022]

[0023] Where:

[0024] ET 0 is the reference crop evapotranspiration / mm; Δ is the slope of the saturated water vapor pressure curve; R n is the net radiation / MJ·m -2 ·d -1 ; G is soil heat flux / MJ·m -2 ·d -1 ; γ is the hygrometer constant / KPa·℃ -1; T is the average temperature / ℃; v 2 is the wind speed at 2 meters above the ground / m·s -1 ; e is the air saturated water vapor pressure / KPa; e a is the actual water vapor pressure of air / Kpa; where:

[0025] P is atmospheric pressure / KPa; λ is latent heat of vaporization / MJ·Kg -1 ;

[0026] z is the altitude above sea level / m; T avg is the daily average temperature / ℃; λ=(2.501-2.361×10 -3 T avg );

[0027] T d is the atmospheric temperature / ℃;

[0028] T max is the maximum temperature / ℃; T min is the minimum temperature / ℃;

[0029] RH max Maximum air humidity / %; RH min is the minimum air humidity / %;

[0030] G day is the daily soil heat flux / MJ·m -2 ·d -1 ; G month,k+1 is the soil heat flux in the k+1th month / MJ·m -2 ·d -1 .

[0031] The precipitation utilization rate is determined based on the daily precipitation P, and the determination principle is:

[0032] Precipitation on the day P day When the precipitation is 5-30 mm, the precipitation utilization coefficient Ua is 1;

[0033] Precipitation on the day P day When the precipitation is 30-50 mm, the precipitation utilization coefficient Ua is 0.6;

[0034] Precipitation on the day P day When it is greater than 50 mm, the precipitation utilization coefficient Ua is 0.3;

[0035] Precipitation on the day P day When it is less than 5 mm, the precipitation utilization coefficient Ua is 0, which is regarded as invalid precipitation.

[0036] Maximum effective accumulated temperature during the growth period C is the crop growth period; GDD is the effective accumulated temperature during the growth period, and the calculation formula is:

[0037] GDD=T avg -T base

[0038] Where, T base The minimum temperature required for crop activity / ℃.

[0039] The determination principle of whether irrigation is needed in the irrigation decision area is:

[0040] When the effective precipitation in the i-th growth period P ≥ k (β i ×W), no irrigation is required during this growth period. i =0;

[0041] When the effective precipitation in the i-th growth period P<k(β i ×W), irrigation is required during this growth period;

[0042] Where k is a constant coefficient.

[0043] The range of constant coefficient k is: k∈[0.75, 1]; where the value of k is proportional to the field water holding capacity θ tc and field saturated water contentθ s The absolute value of the difference between tc =θ s , k=0.75.

[0044] Precision irrigation decision-making system based on crop growth model and weather forecast, including meteorological data acquisition module, reference crop evapotranspiration calculation module, optimal growth period water requirement calculation module, effective precipitation estimation module, irrigation decision-making module, and optimal irrigation amount calculation module;

[0045] The meteorological data acquisition module is used to acquire meteorological data of crops in each growth period in the irrigation decision area;

[0046] The reference crop evapotranspiration calculation module is used to calculate the reference crop evapotranspiration ET corresponding to each growth period of crops in the irrigation decision area according to meteorological data using the FAO56PM formula 0 The theoretical water requirement W of the i-th growth period in the whole growth period is calculated by the reference crop evapotranspiration and the growth period crop coefficient Kc. i and the proportion of water demand β i ;

[0047] The optimal growth period water requirement calculation module is used to optimize and calculate the optimal growth period water requirement W of crops in the entire growth period in a typical hydrological year by using a crop growth model;

[0048] The effective precipitation estimation module is used to estimate the daily precipitation P day As a reference value of effective precipitation P, the effective precipitation is estimated according to the weather forecast;

[0049] The irrigation decision-making module is used to compare the effective precipitation P with the optimal water requirement β of the i-th growth period. i ×W quantitative relationship, determine whether it is necessary to irrigate the irrigation decision area;

[0050] The optimal irrigation amount calculation module is used to calculate and determine the optimal irrigation amount I of the crops in the irrigation decision area in the i-th growth period when the irrigation decision area needs to be irrigated. i ;

[0051] The system also includes a memory, a processor, and a computer program stored on the memory and executable on the processor.

[0052] The present invention has the following beneficial effects:

[0053] Compared with the existing technology, the reference crop evapotranspiration ET corresponding to each growth period of crops in the irrigation decision area is calculated by using the FAO56PM formula based on meteorological data. 0 The theoretical water requirement W of the i-th growth period in the whole growth period is calculated by the reference crop evapotranspiration and the growth period crop coefficient Kc. i and the proportion of water demand β i The crop growth model is used to optimize and calculate the optimal water requirement W of crops during the entire growth period in a typical hydrological year, with daily precipitation P day As a reference value of effective precipitation P, the effective precipitation is estimated according to the weather forecast, and the effective precipitation P is compared with the optimal water requirement β of the i-th growth period. i ×W, determine whether the irrigation decision area needs to be irrigated. When the irrigation decision area needs to be irrigated, the optimal irrigation amount I of the crops in the irrigation decision area in the i-th growth period is calculated according to the formula i , can make irrigation decisions based on the actual water demand of crops, so as to accurately irrigate the irrigation decision area, improve the pertinence and accuracy of irrigation decisions, and thus improve the utilization rate of water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a flow chart of the precise irrigation decision-making method based on crop growth model and weather forecast of the present invention;

[0055] Figure 2 This is a structural block diagram of the precise irrigation decision-making system based on crop growth model and weather forecast of the present invention. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with specific implementation methods, wherein the accompanying drawings are only used for exemplary descriptions and represent only schematic diagrams rather than actual drawings, and should not be understood as limiting the present invention. In order to better illustrate the specific implementation methods of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product.

[0057] The specific implementation process of the technical solution of the present invention includes the following steps:

[0058] Step 1: Calculate the reference crop evapotranspiration ET corresponding to each growth period of crops in the irrigation decision area using the FAO56PM formula based on meteorological data 0 ;

[0059] The calculation formula for reference crop evapotranspiration ET0 is:

[0060]

[0061] Where:

[0062] ET 0 is the reference crop evapotranspiration / mm; Δ is the slope of the saturated water vapor pressure curve; R n is the net radiation / MJ·m -2 ·d -1 ; G is soil heat flux / MJ·m -2 ·d -1 ; γ is the hygrometer constant / KPa·℃ -1 ; T is the average temperature / ℃; v 2 is the wind speed at 2 meters above the ground / m·s -1 ; e is the air saturated water vapor pressure / KPa; e a is the actual water vapor pressure of air / Kpa; where:

[0063] P is atmospheric pressure / KPa; λ is latent heat of vaporization / MJ·Kg -1 ;

[0064] z is the altitude above sea level / m; T avg is the daily average temperature / ℃; λ=(2.501-2.361×10 -3 T avg );

[0065] T dis the atmospheric temperature / ℃;

[0066] T max is the maximum temperature / ℃; T min is the minimum temperature / ℃;

[0067] RH max Maximum air humidity / %; RH min is the minimum air humidity / %;

[0068] G day is the daily soil heat flux / MJ·m -2 ·d -1 ; G month,k+1 is the soil heat flux in the k+1th month / MJ·m -2 ·d -1 .

[0069] Step 2: Calculate the theoretical water requirement W for the i-th growth period in the whole growth period by referring to the crop evapotranspiration and the crop coefficient Kc during the growth period. i and the proportion of water demand β i , where W i =Kc×ET 0 ; n is the total number of reproductive periods;

[0070] Step 3: Use the crop growth model to optimize and calculate the optimal water requirement W of crops during the entire growth period in a typical hydrological year. The calculation formula is: W = K 1 ×(K 2 -K 3 GDD max ), where GDD max is the maximum effective accumulated temperature during the growth period / ℃; K 1 , K 2 , K 3 are coupling constant coefficients; among them, the maximum effective accumulated temperature during the growth period C is the crop growth period; GDD is the effective accumulated temperature during the growth period, and the calculation formula is:

[0071] GDD=T avg -T base

[0072] Where, T base The minimum temperature required for crop activity / ℃.

[0073] The optimization process of the optimal water requirement W during the growth period is as follows:

[0074] Step 31: Calculate the crop yield according to the evolution formula of the yield-water response relationship in the AquaCrop model, where the expression of the evolution formula is specifically:

[0075] B=WP×∑Tr (1)

[0076] Y=B×HI (2)

[0077]

[0078] Where B is the aboveground biomass, kg·m -2 ; WP is water productivity / kg·m -2 mm -1 ; WP * is the correction value of WP; Tr is the actual transpiration / mm; Y is the crop yield / kg·m -2 ; HI is the crop harvest index / %; For the CO 2 Concentration;

[0079] Step 32: Based on the meteorological data in the irrigation decision area, the relationship between crop yield, water requirement during the growth period, and maximum effective accumulated temperature during the growth period is fitted using the water-heat coupling function. The specific expression is as follows:

[0080] Y=K 4 -K 5 GDD max -K 2 W+K 6 W 2 +K 7 GDD max 2 +K 3 WGDD max (4)

[0081] In the formula, K 4 , K 5 , K 6 , K 7 are coupling constant coefficients;

[0082] Step 33: Derivative the two sides of equation (4) and let The calculation formula for the optimal water requirement W during the growth period can be obtained: W = K 1 ×(K 2 -K 3 GDD max );

[0083] Step 4: Take daily precipitation P dayAs a reference value of effective precipitation P, the effective precipitation is estimated according to the weather forecast, where P = Ua × P day , Ua is the precipitation utilization coefficient, by comparing the effective precipitation P with the optimal water requirement β of the i-th growth period i ×W quantitative relationship, determine whether irrigation is needed in the irrigation decision area;

[0084] The principles for determining whether irrigation is needed in the irrigation decision area are as follows:

[0085] When the effective precipitation in the i-th growth period P ≥ k (β i ×W), no irrigation is required during this growth period. i =0;

[0086] When the effective precipitation in the i-th growth period P<k(β i ×W), irrigation is required during this growth period;

[0087] Where k is a constant coefficient.

[0088] The range of constant coefficient k is: k∈[0.75, 1]; where the value of k is proportional to the field water holding capacity θ tc and field saturated water contentθ s The absolute value of the difference between tc =θ s , k=0.75.

[0089] The precipitation utilization rate is determined based on the daily precipitation P, and the determination principle is:

[0090] Precipitation on the day P day When the precipitation is 5-30 mm, the precipitation utilization coefficient Ua is 1;

[0091] Precipitation on the day P day When the precipitation is 30-50 mm, the precipitation utilization coefficient Ua is 0.6;

[0092] Precipitation on the day P day When it is greater than 50 mm, the precipitation utilization coefficient Ua is 0.3;

[0093] Precipitation on the day P day When it is less than 5 mm, the precipitation utilization coefficient Ua is 0, which is regarded as invalid precipitation.

[0094] Step 5: When irrigation is required in the irrigation decision area, the optimal irrigation amount I of the crops in the irrigation decision area in the i-th growth period is determined according to the calculation results of the following formula: i , the calculation formula is: i =β i ×WP-θ tc-Wk, where θ tc Field water holding capacity / m 3 / m 3 , and θ tc =0.65θ s ,θ s is the field saturated water content / m 3 / m 3 ; γ rz Soil bulk density / Kg / m 3 ; Wk is the groundwater recharge.

[0095] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A precise irrigation decision-making method based on crop growth model and weather forecast, characterized in that: include: The reference crop evapotranspiration ET0 corresponding to each growth period of crops in the irrigation decision area is calculated using the FAO56PM formula according to meteorological data. The theoretical growth period water requirement W of the i-th growth period in the whole growth period is calculated by the reference crop evapotranspiration and the growth period crop coefficient Kc. i and the proportion of water demand β i , where W i =Kc×ET0; n is the total number of reproductive periods; The crop growth model is used to optimize and calculate the optimal water requirement W of crops during the entire growth period in a typical hydrological year. The calculation formula is: W = K1 × (K2-K3GDD max ), where GDD max is the maximum effective accumulated temperature during the growth period / ℃; K1, K2, K3 are all coupling constant coefficients; Daily precipitation P day As a reference value of effective precipitation P, the effective precipitation is estimated according to the weather forecast, where P = Ua × P day , Ua is the precipitation utilization coefficient, by comparing the effective precipitation P with the optimal water requirement β of the i-th growth period i ×W quantitative relationship, determine whether it is necessary to irrigate the irrigation decision area; When the irrigation decision area needs to be irrigated, the optimal irrigation amount I of the crops in the irrigation decision area in the i-th growth period is determined according to the calculation result of the following formula: i , the calculation formula is: i =β i ×WP-θ tc -Wk, where θ tc Field water holding capacity / m 3 / m 3 , and θ tc =0.65θ s ,θ s is the field saturated water content / m 3 / m 3 ; γ rz Soil bulk density / Kg / m 3 ; Wk is the groundwater recharge.

2. The precise irrigation decision-making method based on crop growth model and weather forecast according to claim 1, characterized in that: The calculation formula for reference crop evapotranspiration ET0 is: Where: ET0 is the reference crop evapotranspiration / mm; Δ is the slope of the saturated water vapor pressure curve; R n is the net radiation / MJ·m -2 ·d -1 ; G is soil heat flux / MJ·m -2 ·d -1 ; γ is the hygrometer constant / KPa·℃ -1 ; T is the average temperature / ℃; v2 is the wind speed at 2 meters above the ground / m·s -1 ; e is the air saturated water vapor pressure / KPa; e a is the actual water vapor pressure of air / Kpa; where: P is atmospheric pressure / KPa; λ is latent heat of vaporization / MJ·Kg -1 ; z is the altitude above sea level / m; T avg is the daily average temperature / ℃; λ=(2.501-2.361×10 -3 T avg ); T d is the atmospheric temperature / ℃; T max is the maximum temperature / ℃; T min is the minimum temperature / ℃; RH max is the maximum air humidity / %; RH min is the minimum air humidity / %; G day is the daily soil heat flux / MJ·m -2 ·d -1 ; G month,k+1 is the soil heat flux in the k+1th month / MJ·m -2 ·d -1 .

3. The precise irrigation decision-making method based on crop growth model and weather forecast according to claim 1, characterized in that: The precipitation utilization rate is determined based on the daily precipitation P, and the determination principle is: Precipitation on the day P day When the precipitation is 5-30 mm, the precipitation utilization coefficient Ua is 1; Precipitation on the day P day When the precipitation is 30-50 mm, the precipitation utilization coefficient Ua is 0.6; Precipitation on the day P day When it is greater than 50 mm, the precipitation utilization coefficient Ua is 0.3; Precipitation on the day P day When it is less than 5 mm, the precipitation utilization coefficient Ua is 0, which is regarded as invalid precipitation.

4. The method for precise irrigation decision-making based on crop growth model and weather forecast according to claim 1, characterized in that: Maximum effective accumulated temperature during the growth period C is the crop growth period; GDD is the effective accumulated temperature during the growth period, and the calculation formula is: GDD=T avg -T base Where, T base The minimum temperature required for crop activity / ℃.

5. The method for precise irrigation decision-making based on crop growth model and weather forecast according to claim 1, characterized in that: The determination principle of whether irrigation is needed in the irrigation decision area is: When the effective precipitation in the i-th growth period P ≥ k (β i ×W), no irrigation is required during this growth period. i =0; When the effective precipitation in the i-th growth period P<k(β i ×W), irrigation is required during this growth period; Where k is a constant coefficient.

6. The method for precise irrigation decision-making based on crop growth model and weather forecast according to claim 5, characterized in that: The range of constant coefficient k is: k∈[0.75, 1]; where the value of k is proportional to the field water holding capacity θ tc and field saturated water contentθ s The absolute value of the difference between tc =θ s , k=0.

75.

7. A precise irrigation decision-making system based on crop growth model and weather forecast, characterized in that: It includes meteorological data acquisition module, reference crop evapotranspiration calculation module, optimal growth period water requirement calculation module, effective precipitation estimation module, irrigation decision-making module, and optimal irrigation amount calculation module; The meteorological data acquisition module is used to acquire meteorological data of crops in each growth period in the irrigation decision area; The reference crop evapotranspiration calculation module is used to calculate the reference crop evapotranspiration ET0 corresponding to each growth period of crops in the irrigation decision area according to meteorological data using the FAO56PM formula, and calculate the theoretical growth period water requirement W of the i-th growth period in the whole growth period through the reference crop evapotranspiration and the growth period crop coefficient Kc. i and the proportion of water demand β i , where W i =Kc×ET0; n is the total number of reproductive periods; The optimal growth period water requirement calculation module is used to optimize and calculate the optimal growth period water requirement W of crops in the whole growth period in a typical hydrological year by using the crop growth model. The calculation formula is: W = K1 × (K2-K3GDD max ), where GDD max is the maximum effective accumulated temperature during the growth period / ℃; K1, K2, K3 are coupling constant coefficients; the maximum effective accumulated temperature during the growth period C is the crop growth period; GDD is the effective accumulated temperature during the growth period, and the calculation formula is: GDD = T avg -T base , where T base The minimum temperature required for crop activity / ℃; The effective precipitation estimation module is used to estimate the daily precipitation P day As a reference value of effective precipitation P, the effective precipitation is estimated according to the weather forecast, where P = Ua × P day , Ua is the precipitation utilization coefficient, where the precipitation utilization rate is determined according to the daily precipitation P, and the determination principle is: Precipitation on the day P day When the precipitation is 5-30 mm, the precipitation utilization coefficient Ua is 1; Precipitation on the day P day When the precipitation is 30-50 mm, the precipitation utilization coefficient Ua is 0.6; Precipitation on the day P day When it is greater than 50 mm, the precipitation utilization coefficient Ua is 0.3; Precipitation on the day P day When it is less than 5 mm, the precipitation utilization coefficient Ua is 0, which is regarded as invalid precipitation; The irrigation decision-making module is used to compare the effective precipitation P with the optimal water requirement β of the i-th growth period. i ×W, to determine whether the irrigation decision area needs to be irrigated; wherein the determination principle is: When the effective precipitation in the i-th growth period P ≥ k (β i ×W), no irrigation is required during this growth period. i =0; When the effective precipitation in the i-th growth period P<k(β i ×W), irrigation is required during the growth period; where k is a constant coefficient, and the range of the constant coefficient k is: k∈[0.75, 1]; where the value of k is proportional to the field water holding capacity θ tc and field saturated water contentθ s The absolute value of the difference between tc =θ s When k = 0.75; The optimal irrigation amount calculation module is used to determine the optimal irrigation amount I of the crops in the irrigation decision area in the i-th growth period according to the calculation result of the following formula when irrigation is required in the irrigation decision area. i , the calculation formula is: i =β i ×WP-θ tc -Wk, where θ tc Field water holding capacity / m 3 / m 3 , and θ tc =0.65θ s ,θ s is the field saturated water content / m 3 / m 3 ; γ rz Soil bulk density / Kg / m 3 ; Wk is the groundwater recharge; The calculation formula of reference crop evapotranspiration ET0 is: Where: ET0 is the reference crop evapotranspiration / mm; Δ is the slope of the saturated water vapor pressure curve; R n is the net radiation / MJ·m -2 ·d -1 ; G is soil heat flux / MJ·m -2 ·d -1 ; γ is the hygrometer constant / KPa·℃ -1 ; T is the average temperature / ℃; v2 is the wind speed at 2 meters above the ground / m·s -1 ; e is the air saturated water vapor pressure / KPa; e a is the actual water vapor pressure of air / Kpa; where: P is atmospheric pressure / KPa; λ is latent heat of vaporization / MJ·Kg -1 ; z is the altitude above sea level / m; T avg is the daily average temperature / ℃; λ=(2.501-2.361×10 -3 T avg ); T d is the atmospheric temperature / ℃; T max is the maximum temperature / ℃; T min is the minimum temperature / ℃; RH max is the maximum air humidity / %; RH min is the minimum air humidity / %; G day is the daily soil heat flux / MJ·m -2 ·d -1 ; G month,k+1 is the soil heat flux in the k+1th month / MJ·m -2 ·d -1 .

8. The precise irrigation decision-making system based on crop growth model and weather forecast according to claim 7, characterized in that: The system further comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor can implement the steps of the method described in any one of claims 1 to 6 when executing the program.

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