A method for evaluating irrigation water use efficiency considering regional water consumption analysis

Abstract

This invention discloses an irrigation water efficiency evaluation method considering regional water consumption analysis. Firstly, addressing the issue of unclear definition of the seepage cycle in effective precipitation estimation, it proposes to calculate the seepage amount of each precipitation event throughout the entire growth period from after crop harvest, and achieves accurate calculation of effective precipitation through the carryover of seepage compensation. During the crop growth period, a daily-scale water consumption analysis logic based on "precipitation utilization first, irrigation supplementary supply, and soil and groundwater security" is constructed. Precipitation ET, irrigation ET, and other ETs are quantitatively separated, and the regional irrigation water efficiency is evaluated using the proportion of irrigation ET in the regional irrigation water withdrawal. This invention effectively solves the pain points of difficult accurate separation of irrigation ET and insufficient multi-temporal and spatial scale evaluation techniques for irrigation water efficiency. It can clearly reveal the crop's potential for precipitation utilization and its dependence on irrigation, providing technical support for irrigation water management decisions and optimal water resource allocation in irrigation districts.

Description

Technical Field

[0001] This invention belongs to the field of farmland water conservancy technology, specifically relating to a method for evaluating irrigation water efficiency that considers regional water consumption analysis. Background Technology

[0002] Irrigation water use efficiency is a core indicator for measuring the level of agricultural water resource management. Scientific and accurate evaluation of irrigation water use efficiency is of great significance for the optimal allocation of regional water resources and sustainable agricultural development. Currently, commonly used methods for evaluating irrigation water use efficiency both domestically and internationally mainly include the water balance method, evapotranspiration inversion method, isotope tracing method, and model simulation method.

[0003] The water balance method is the most basic and widely used approach. It calculates crop water consumption and irrigation water use by establishing a balance between inputs (precipitation, irrigation) and outputs (evapotranspiration, seepage, runoff) at the field or regional scale. While this method has a clear principle and readily available parameters, it suffers from significant subjectivity in defining effective precipitation and dividing the timeframes for deep seepage. Inappropriate selection of seepage intervals often leads to deviations in the calculation of effective precipitation, thus affecting the accuracy of irrigation water efficiency evaluation. The evapotranspiration inversion method primarily uses remote sensing technology to obtain regional evapotranspiration and combines it with precipitation data to infer irrigation water consumption, making it suitable for large-scale regional irrigation efficiency assessment. However, it is limited by the spatiotemporal resolution of remote sensing data and struggles to precisely distinguish the contributions of precipitation, irrigation, and soil water storage to evapotranspiration, resulting in difficulty in accurately separating irrigation water consumption. The isotope tracing method quantitatively distinguishes the contributions of different water sources to crop water consumption by measuring the hydrogen and oxygen isotope composition in plant stems or soil water, demonstrating a good physical mechanism. However, this method is costly and difficult to promote for application at regional scales and long-term time series. Model simulation methods assess irrigation regimes and water use efficiency by simulating water transport processes in the soil-crop-atmosphere continuum. Although models can simulate complex farmland hydrological processes, they suffer from limitations such as difficulties in parameter calibration and high requirements for basic data. Furthermore, in terms of analyzing water consumption components, most models only output total evapotranspiration and fail to provide daily detailed analyses of precipitation ET, irrigation ET, and other ETs, making it difficult to reveal the actual potential of crops to utilize natural precipitation and their dependence on irrigation.

[0004] In summary, existing methods for evaluating irrigation water efficiency still have shortcomings in accurately calculating effective precipitation, finely analyzing the composition of crop water consumption, and accurately assessing the total regional irrigation water consumption. There is an urgent need to establish a systematic, accurate, and highly operable method for evaluating irrigation water efficiency. Summary of the Invention

[0005] To address the aforementioned shortcomings in existing technologies, the irrigation water efficiency evaluation method considering water consumption analysis provided by this invention solves the problems that existing water consumption analysis methods are unable to precisely distinguish the quantitative contributions of precipitation ET, irrigation ET, and other ET at the daily scale, and that field-scale water consumption analysis results are difficult to extend to the regional scale.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: a method for evaluating irrigation water efficiency considering regional water consumption analysis, comprising the following steps: S100. Starting from the time the crop is harvested, the amount of infiltration during each rainfall event throughout the entire growth period is calculated backwards and then summed up to obtain the effective rainfall amount for each rainfall event during the entire growth period of the crop in the irrigated area. S200. After crop sowing, water consumption analysis is performed based on each effective precipitation to determine the total irrigation ET for a single crop. The water consumption analysis includes sequentially performing daily-scale rainfall ET allocation, daily-scale irrigation ET allocation, and daily-scale other ET allocation; S300. The total irrigation ET for all crops in the irrigated area is summed to obtain the regional irrigation ET. S400. Determine the regional irrigation water efficiency based on the total irrigation water intake and regional irrigation ET.

[0007] Furthermore, in S100, any first... The effective precipitation of this rainfall for: In the formula, For the first The amount of precipitation in each precipitation event. For the first Runoff generated by the second precipitation For the first The deep seepage flow that will occur between the next rainfall event and the next precipitation event. For the first The amount of leakage compensation carried over from the previous rainfall event. For the first The amount of leakage compensation carried over from the previous rainfall event. , This refers to the total number of precipitation events during the crop's growing season. Among them, the Leakage compensation for secondary precipitation The calculation formula is: .

[0008] Further, step S200 includes the following sub-steps: S201. Determine the total water consumption of a single crop; S202. Starting from crop sowing, analyze daily water consumption on a daily time scale. S203. Based on the daily water consumption analysis, the water consumption analysis results at different time scales are summarized, and the total irrigation ET for a single crop is determined.

[0009] Furthermore, in S201, the total water consumption of a single crop for: In the formula, This represents the precipitation during the specified period. This refers to the amount of irrigation water used during the specified time period. This represents the groundwater recharge during the specified period. This represents the change in soil water storage in the crop root zone over a given period of time. This represents the amount of deep seepage caused by precipitation or irrigation during a given period. This refers to the surface runoff generated by precipitation or irrigation during a given period. This represents the soil moisture content of the drainage soil profile per unit time. The thickness of the drainage soil profile. For time step, For the potential maximum storage capacity, denoted as groundwater depth, and a and b are the crop coefficient and root water absorption coefficient of soil type and its hydraulic properties, respectively, which vary with different soil types.

[0010] Furthermore, the crop coefficient includes the soil evaporation coefficient. and crop transpiration coefficient ; Regarding the soil evaporation coefficient, when the transport of water from the lower soil layer to the surface layer is limited, soil evaporation is divided into an energy evaporation stage and a rate decrease stage. During the energy evaporation stage, the soil evaporation coefficient satisfies: During the rate decrease phase, the soil evaporation coefficient satisfies: In the formula, Evaporation rate For the maximum soil evaporation rate, For reference crop evapotranspiration, The soil evaporation coefficient when the surface is completely wet, i.e., the maximum soil evaporation coefficient, is 1-CC. * This refers to the bare ground surface not covered by crop canopy. This is the adjusted canopy coverage. Canopy coverage, This is the evaporation attenuation coefficient; For the crop transpiration coefficient Under conditions of sufficient water and water stress, it satisfies the following respectively: In the formula, This represents the actual crop evapotranspiration. This represents the stomatal closure coefficient under water stress. The root water absorption coefficient is the volume of water absorbed from a unit volume of soil per unit time.

[0011] Furthermore, in step S202, the process of analyzing water consumption is as follows: Using the daily water consumption calculated based on water balance as a reference, after crop sowing, water consumption analysis is performed in conjunction with the effective precipitation calculation results corresponding to each rainfall during the growth period of each crop. When there is no irrigation or rainfall during the growing season, the crop water consumption is allocated to other ET; When there is rainfall during the growing season, the crop's water consumption is prioritized for the allocation of rainfall ET, and any shortfall is allocated to other ET; When there is irrigation during the growing season, and the effective rainfall in the early stage has not been fully allocated, the crop water consumption is allocated in the following order: rainfall ET, irrigation ET, and any shortfall is allocated to other ET. When there is no rainfall during the growing season and only irrigation is available, the crop water consumption is first allocated to irrigation ET, and any remaining water is allocated to other ET.

[0012] Furthermore, in step S200, during the water consumption analysis process, rainfall ET allocation is performed, including: After determining the sowing date Total rainfall ET for: Determine the first The daily rainfall ET is: The remaining water demand is determined as follows: Determine to defer to the first Remaining rainfall for the day for: In the formula, For the first Effective precipitation per day For the first The total amount of remaining effective precipitation at the beginning of the day. For the first The amount of precipitation consumed by the day (ET) For the first Daily water consumption For the first Total amount of precipitation (ET) For the first The remaining water consumption for the day.

[0013] Furthermore, in step S200, during the water consumption analysis process, irrigation ET allocation is performed, including: Determine the first Total water volume for irrigation of ET on that day for: Determine the first The irrigation ET allocated per day is: The remaining water demand is determined as follows: Determine to defer to the first The remaining irrigation amount for the day is: In the formula, For the first Daily effective precipitation For the first The total amount of remaining effective precipitation at the beginning of the day. For the first The amount of precipitation consumed by the day (ET) For the first The remaining water consumption per day For the first The remaining water demand after the distribution of precipitation For the first Total water volume for irrigation of ET For the first The remaining water demand after irrigation allocation For the first The irrigation ET consumed by the day, For the first The remaining amount after deducting the irrigation ET consumed on that day from the total irrigation water volume for the day is carried over to the next day.

[0014] Further, in S300, the regional irrigation ET is: In the formula, For regional irrigation ET, For the first Total irrigation ET for crops For the irrigation area The first crop Irrigation of ET per pixel point, For the first in the region Crop planting area, This represents the total number of pixels within the irrigation area. This represents the total number of crop types.

[0015] Furthermore, in S400, the irrigation water efficiency is... : In the formula, For regional irrigation ET, This represents the total amount of irrigation water used in the region. For the region number Water intake from each water source This represents the total number of water sources.

[0016] The beneficial effects of this invention are as follows: (1) A refined analysis of crop water consumption composition has been achieved. This invention uses a daily scale and, based on water balance calculations, quantitatively analyzes precipitation ET, irrigation ET, and other ET on a daily basis according to the water consumption allocation logic of "precipitation priority, irrigation subsequent, and soil water and groundwater as a backup." It can clearly depict the contribution dynamics of each water source at different growth stages, reveal the crop's potential to utilize natural precipitation and its dependence on irrigation, and provide accurate decision-making basis for optimizing irrigation systems.

[0017] (2) Provides an effective scale conversion method from field to region. This invention extends the water consumption composition of a single crop to regional irrigation ET by weighting the water consumption analysis results at the pixel scale with the crop planting area. It solves the data connection problem between the field scale and the regional scale, and makes the evaluation of regional irrigation water efficiency both supported by micro-mechanisms and applicable to macro-management.

[0018] (3) The evaluation indicators have clear physical meaning and are highly operable. This invention uses "regional irrigation ET / total regional irrigation water consumption" as an evaluation index for irrigation water efficiency, which directly reflects the proportion of irrigation water actually consumed and utilized by crops. Compared with traditional efficiency indicators characterized by yield or output value, it can more accurately reflect the effective utilization of irrigation water resources. Moreover, the required parameters can be obtained through conventional meteorological, soil and irrigation management data, making it easy to promote and apply in various irrigation areas.

[0019] (4) It can support multi-objective irrigation management decisions. By analyzing water consumption results, managers can intuitively grasp the relationship between precipitation ET, irrigation ET, and other ET under different irrigation regimes, as well as their substitution effects. This provides a quantitative basis for formulating water-saving irrigation plans, determining appropriate irrigation frequency and volume, and adjusting regional water resource allocation strategies, which helps to maximize irrigation water use efficiency while ensuring crop yield. Attached Figure Description

[0020] Figure 1 This invention provides a method for evaluating irrigation water efficiency that considers regional water consumption analysis.

[0021] Figure 2 This invention provides an analysis of water consumption in maize under different irrigation regimes. Detailed Implementation

[0022] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0023] This invention provides a method for evaluating irrigation water efficiency considering regional water consumption analysis, with reference to... Figure 1 This includes the following steps: S100. Starting from the time the crop is harvested, the amount of infiltration during each rainfall event throughout the entire growth period is calculated backwards and then summed up to obtain the effective rainfall amount for each rainfall event during the entire growth period of the crop in the irrigated area. S200. After crop sowing, water consumption analysis is performed based on each effective precipitation to determine the total irrigation ET for a single crop. The water consumption analysis includes sequentially performing daily-scale rainfall ET allocation, daily-scale irrigation ET allocation, and daily-scale other ET allocation; S300. The total irrigation ET for all crops in the irrigated area is summed to obtain the regional irrigation ET. S400. Determine the regional irrigation water efficiency based on the total irrigation water intake and regional irrigation ET.

[0024] In S100 of this embodiment, effective precipitation, as a key variable in the farmland water cycle, is a core indicator for optimizing crop irrigation systems and evaluating agricultural water resource utilization efficiency. In this invention, effective precipitation is defined as the portion of precipitation that can be used to meet the evapotranspiration requirements of crops; it does not include surface runoff or the portion that seeps into the crop root zone.

[0025] This invention modifies the traditional water balance method and proposes a method for reverse calculation of effective precipitation based on the water balance method. By calculating the effective precipitation for each rainfall event throughout the entire growth period, starting from crop harvest, and then summing these calculations, the total effective precipitation for the entire growth period is obtained. This method calculates effective precipitation more accurately, reduces errors caused by unclear infiltration periods, and improves the accuracy and reliability of water balance calculations. The specific calculation process is as follows: The last rainfall during the reproductive period ( = ): The second to last rainfall during the reproductive period ( = ): At this point, the leakage gap left by the last rainfall needs to be deducted. Therefore, any first [period] during the crop's growth period ( The effective precipitation of this rainfall event for: In the formula, For the first Rainfall amount (mm) of each precipitation event; For the first Runoff generated by the precipitation (mm); For the first Deep seepage flow (mm) generated between the occurrence of one precipitation event and the next precipitation event. For the first The leakage compensation amount (mm) carried over from the previous rainfall to the next rainfall. For the first The leakage compensation amount (mm) carried over from the previous rainfall to the next rainfall. , This represents the total number of precipitation events during the crop's growing season.

[0026] Among them, the Leakage compensation for secondary precipitation The calculation formula is: This invention addresses the limitation of traditional water balance methods in accurately defining the duration of deep seepage by proposing a "backward calculation method" based on a reverse reasoning approach to calculate effective precipitation. This method reduces calculation errors caused by using deterministic seepage intervals by calculating the effective precipitation for each rainfall event sequentially from the end of the growing season.

[0027] In S200 of this embodiment, crop water consumption analysis is the basis for evaluating the water use efficiency of irrigation areas. However, under the dual pressures of climate change and water scarcity, a single study of total water consumption is no longer sufficient to meet the needs of modern agriculture for refined water management. This invention analyzes water consumption based on effective precipitation, quantitatively identifying the contributions of precipitation, irrigation water, and soil water storage to crop water consumption from the perspective of water source composition, revealing the crop's potential for utilizing natural precipitation and its dependence on irrigation.

[0028] S200 of this embodiment of the invention includes the following sub-steps: S201. Determine the total water consumption of a single crop; S202. Starting from crop sowing, analyze daily water consumption on a daily time scale. S203. Based on the daily water consumption analysis, the water consumption analysis results at different time scales are summarized, and the total irrigation ET for a single crop is determined.

[0029] In S201, the total water consumption of a single crop for: In uniformly moist soil, it can be assumed that the daily decrease in soil moisture content is constant throughout the drainage profile. Based on the actual soil moisture content, the amount of water seeping from the bottom of the soil profile at the end of each day is: To simulate the redistribution of water in the soil layer, drainage of the soil profile, and infiltration of precipitation or irrigation, the following drainage function is used: The amount of rainfall lost to surface runoff is estimated using the following formula: Considering the water retention curve (h-θ relationship) and the relationship between matrix potential (h) and hydraulic conductivity (K), the process of shallow groundwater flowing upwards towards the surface soil can be described by the Darcy equation, and the groundwater recharge is given by the following exponential equation: In the formula, Rainfall amount (mm) during the time period; The irrigation water volume (mm) during the time period; The groundwater recharge amount (mm) during the time period; The change in soil water storage in the crop root zone during the time period is measured in mm. The amount of deep seepage caused by precipitation or irrigation during the time period (mm). Surface runoff (mm) generated by precipitation or irrigation during the time period. This represents the soil moisture content of the drainage soil profile per unit time. ; refers to drainage characteristics; This represents the actual soil moisture content at depth 1. ; This represents the saturated soil moisture content. ; This refers to the soil moisture content in the field. ; The thickness of the drainage soil profile, in meters (m). For time step, The potential maximum storage capacity (mm); Number of curves; denoted as groundwater depth in meters; a and b are the crop coefficient and root water absorption coefficient for soil type and hydraulic properties, respectively, which vary with soil type.

[0030] In this embodiment, the crop coefficient includes the soil evaporation coefficient. and crop transpiration coefficient ; Regarding the soil evaporation coefficient, when the transport of water from the lower soil layer to the surface layer is limited, soil evaporation is divided into an energy evaporation stage and a rate decrease stage. Energy-limited stage: When rainfall or irrigation occurs, water evaporation mainly occurs in the thin layer of the earth's surface in close contact with the atmosphere. As long as there is water on the surface, the evaporation rate is in the energy-limited stage, which is the maximum evaporation rate. Therefore, the soil evaporation coefficient satisfies: Evaporation Rate Decline Phase: After all surface soil moisture has evaporated, soil evaporation enters the rate decline phase. In this phase, the evaporation rate is not only energy-limited but also influenced by soil hydraulic properties. As soil moisture content decreases, the ability to transport water to the surface soil weakens, and the evaporation rate decreases accordingly; at this point, the soil evaporation coefficient satisfies: In the formula, Evaporation rate For the maximum soil evaporation rate, For reference crop evapotranspiration (mm); The soil evaporation coefficient when the surface is completely wet, i.e., the maximum soil evaporation coefficient, is 1-CC. * This refers to the bare ground surface not covered by crop canopy. The adjusted canopy cover is intended to account for the shading effects of interrow microradiation and partial canopy cover. Canopy coverage, This is the evaporation attenuation coefficient.

[0031] For crop transpiration: If the root zone has sufficient water, the transpiration rate is at its maximum, and its expression is: If insufficient water in the root zone causes stomatal closure, crop transpiration can be represented as: If root zone water retention causes ventilation stress, crop transpiration can be represented as: Therefore, the actual evapotranspiration of a crop is the sum of transpiration and evaporation, and the crop transpiration coefficient is... Under conditions of sufficient water and water stress, it satisfies the following respectively: In the formula, Tr x Maximum crop transpiration (mm / day); Kcb is the crop transpiration coefficient when the root zone has sufficient water. x Ks represents the crop transpiration coefficient when the root zone has sufficient moisture and the ground surface is completely covered, i.e., the maximum crop transpiration coefficient. aer The ventilation stress coefficient is the factor for water retention. Actual crop evapotranspiration (mm); This represents the stomatal closure coefficient under water stress.

[0032] In this embodiment, the root system coefficient refers to the water lost through transpiration by the crop, which is extracted from the soil by the roots. The water absorption by the roots can be expressed as the water absorption rate of the crop roots. Therefore, the root system water absorption coefficient is the volume of water absorbed from a unit volume of soil per unit time.

[0033] In S202, the process of analyzing water consumption is as follows: Using the daily water consumption calculated based on water balance as a reference, after crop sowing, water consumption analysis is performed in conjunction with the effective precipitation calculation results corresponding to each rainfall during the growth period of each crop. When there is no irrigation or rainfall during the growing season, the crop's water consumption is allocated to other ET; When there is rainfall during the growing season, the crop's water consumption is prioritized for the allocation of rainfall ET, and any shortfall is allocated to other ET; When there is irrigation during the growing season, and the effective rainfall in the early stage has not been fully allocated, the crop water consumption is allocated in the following order: rainfall ET, irrigation ET, and any shortfall is allocated to other ET. When there is no rainfall during the growing season and only irrigation is available, the crop water consumption is first allocated to irrigation ET, and any remaining water is allocated to other ET.

[0034] In the above water consumption analysis process, according to the principle of total water consumption balance, the total water consumption ( ) includes total rainfall ET ( ), Total irrigation ET ( ) and other total ET ( The calculation formula is as follows: In the formula: , , The first The effective rainfall (mm), net irrigation quota (mm), and water consumption (mm) per day, with the crop growing season numbered in days T, of which... =1,2,...,T.

[0035] The analysis of water consumption during the crop growth period begins at sowing, with water consumption analyzed on a daily timescale. Based on the daily water consumption analysis, the results are then summarized into monthly and yearly water consumption analyses. The water consumption analysis process on the first day after sowing is as follows: In the formula: , , , , , These are the water consumption (mm), effective precipitation (mm), net irrigation amount (mm), other ET (mm), rainfall ET (mm), and irrigation ET (mm) for the first day.

[0036] Based on the above water consumption analysis process, rainfall ET allocation is performed, including: After determining the sowing date Total rainfall ET for: Determine the first The daily rainfall ET is: The remaining water demand is determined as follows: Determine to defer to the first Remaining rainfall for the day for: In the formula, For the first Effective precipitation per day (mm); For the first Total remaining effective precipitation at the beginning of the day (mm); For the first Rainfall consumed per day ET (mm); For the first Daily water consumption (mm); For the first Total amount of precipitation ET (mm); For the first Remaining water consumption per day (mm).

[0037] The irrigation ET allocation includes: Determine the first Total water volume for irrigation of ET on that day for: Determine the first The irrigation ET allocated per day is: The remaining water demand is determined as follows: Determine to defer to the first The remaining irrigation amount for the day is: In the formula, For the first Daily effective precipitation (mm); For the first Total remaining effective precipitation at the beginning of the day (mm); For the first Rainfall consumed per day ET (mm); For the first Remaining water consumption per day (mm); For the first The remaining water consumption demand after the distribution of precipitation (mm); For the first Total irrigation water volume for ET (mm); For the first The remaining water demand after irrigation allocation (mm); For the first Daily irrigation consumption ET (mm); For the first The remaining amount (mm) after deducting the irrigation ET consumed on that day from the total irrigation water volume for the day is carried forward to the next day.

[0038] Based on the principle of water balance, this invention establishes a daily-scale water consumption analysis process and establishes a water consumption allocation logic of "prioritizing the use of precipitation, supplementing supply through irrigation, and ensuring soil water and groundwater supply". It achieves precise quantitative analysis of the total water consumption components of crops (precipitation ET, irrigation ET, and other ET).

[0039] In S300 of this embodiment of the invention, the regional irrigation ET is: In the formula, For regional irrigation ET, 10,000 m 3 ; For the first Total irrigation for crops (ET, 10,000 m³) 3 ; For the irrigation area The first crop Irrigation ET (mm) for each pixel point; For the first in the region The planting area of ​​crops is 10,000 mu; This represents the total number of pixels within the irrigation area. This represents the total number of crop types.

[0040] In S400 of this embodiment of the invention, the total regional irrigation water consumption refers to the amount of irrigation water taken from the water source by the region throughout the year. This amount of water is determined by actual measurement, thereby obtaining the irrigation water efficiency. : In the formula, For regional irrigation ET, 10,000 m 3 ; The total irrigation water consumption in the region, in ten thousand cubic meters. 3 ; For the region number Water intake from each water source, 10,000 m³ 3 ; This represents the total number of water sources.

[0041] In this embodiment of the invention, the above-mentioned water consumption analysis method is provided to analyze the water consumption of spring maize under different irrigation systems in 2024.

[0042] Analysis of water consumption under different irrigation systems in 2024 is shown below. Figure 2 In treatment T1, one irrigation was administered at the jointing stage. The total water consumption for this treatment was 481 mm, of which irrigation ET contributed 100 mm (20.8% of the total ET), precipitation ET contributed 143 mm (29.7%), and other ET (mainly soil water consumption) contributed 238 mm (49.5%). Under this treatment, nearly half of the crop's water consumption depended on soil water storage. In treatment T2, one irrigation was administered at both the jointing and heading stages, for a total of two irrigations during the growth period. The total water consumption for this treatment increased to 524 mm, with irrigation ET rising to 180 mm (34.4% of the total ET). Precipitation ET remained at 143 mm (27.3%), while other ET decreased to 201 mm (38.4%). Compared to T1, the proportion of irrigation ET significantly increased, while the proportion of other ET decreased accordingly. The T3 treatment involved irrigating once each at the jointing, heading, and trumpet stages, for a total of three irrigations during the growth period. The total water consumption for this treatment was 526 mm, of which irrigation ET was 260 mm, accounting for 49.4% of the total ET; precipitation ET remained at 143 mm, accounting for 27.2%; and other ET further decreased to 123 mm, accounting for 23.4%.

[0043] The results showed that, under consistent precipitation conditions, irrigation ET significantly increased with increasing irrigation volume, while other ETs decreased accordingly. This trend is consistent with the observations in 2023, further verifying that increasing irrigation volume can increase the proportion of irrigation water in total water consumption and reduce crop dependence on soil water storage. Inter-treatment comparisons showed that the total ET of treatments T2 and T3 differed little, but the water consumption composition was significantly differentiated: treatment T3 increased irrigation ET by 80 mm by increasing the amount of irrigation water, while other ETs decreased by 78 mm, indicating that additional irrigation effectively replaced soil water storage consumption. From the perspective of water consumption dynamics throughout the entire growth period, water consumption in the early growth stage of each treatment was mainly driven by other ETs, with irrigation ET at a relatively low level. This is closely related to the background of water conservation through autumn irrigation and scarce precipitation in the early growth stage in the Hetao Irrigation District. With the implementation of irrigation treatments, the peak irrigation ET occurred during the irrigation period of each treatment, while other ETs showed the opposite trend to irrigation ET, i.e., a brief decrease after irrigation, reflecting the substitution effect of irrigation on soil water storage consumption.

[0044] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only intended to help understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

[0045] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. An irrigation water use efficiency evaluation method considering regional water consumption analysis, characterized by, Includes the following steps: S100. Starting from the time the crop is harvested, the amount of infiltration during each rainfall event throughout the entire growth period is calculated backwards and then summed up to obtain the effective rainfall amount for each rainfall event during the entire growth period of the crop in the irrigated area. S200. After crop sowing, water consumption analysis is performed based on each effective precipitation to determine the total irrigation ET for a single crop. The water consumption analysis includes sequentially performing daily-scale rainfall ET allocation, daily-scale irrigation ET allocation, and daily-scale other ET allocation; S300. The total irrigation ET for all crops in the irrigated area is summed to obtain the regional irrigation ET. S400. Determine the regional irrigation water efficiency based on the total irrigation water intake and regional irrigation ET.

2. The irrigation water use efficiency evaluation method considering regional water consumption analysis according to claim 1, characterized in that, In S100, any one of the following during the crop growth period... The effective precipitation of this rainfall for: In the formula, For the first The amount of precipitation in each precipitation event. For the first Runoff generated by the second precipitation For the first The deep seepage flow that will occur between the next rainfall event and the next precipitation event. For the first The amount of leakage compensation carried over from the previous rainfall event. For the first The amount of leakage compensation carried over from the previous rainfall event. , This refers to the total number of precipitation events during the crop's growing season. Among them, the Leakage compensation for secondary precipitation The calculation formula is: 。 3. The method for evaluating irrigation water efficiency considering regional water consumption analysis according to claim 1, characterized in that, S200 includes the following steps: S201. Determine the total water consumption of a single crop; S202. Starting from crop sowing, analyze daily water consumption on a daily time scale. S203. Based on the daily water consumption analysis, the water consumption analysis results at different time scales are summarized, and the total irrigation ET for a single crop is determined.

4. The method for evaluating irrigation water efficiency considering regional water consumption analysis according to claim 3, characterized in that, In step S201, the total water consumption of a single crop for: In the formula, This represents the precipitation during the specified period. This refers to the amount of irrigation water used during the specified time period. This represents the groundwater recharge during the specified period. This represents the change in soil water storage in the crop root zone over a given period of time. This represents the amount of deep seepage caused by precipitation or irrigation during a given period. This refers to the surface runoff generated by precipitation or irrigation during a given period. This represents the soil moisture content of the drainage soil profile per unit time. The thickness of the drainage soil profile. For time step, For the potential maximum storage capacity, denoted as groundwater depth, and a and b are the crop coefficient and root water absorption coefficient of soil type and its hydraulic properties, respectively, which vary with different soil types.

5. The irrigation water use efficiency evaluation method considering regional water consumption analysis according to claim 4, characterized in that, The crop coefficient includes the soil evaporation coefficient. and crop transpiration coefficient ; Regarding the soil evaporation coefficient, when the transport of water from the lower soil layer to the surface layer is limited, soil evaporation is divided into an energy evaporation stage and a rate decrease stage. During the energy evaporation stage, the soil evaporation coefficient satisfies: During the rate decrease phase, the soil evaporation coefficient satisfies: In the formula, Evaporation rate For the maximum soil evaporation rate, For reference crop evapotranspiration, The soil evaporation coefficient when the surface is completely wet, i.e., the maximum soil evaporation coefficient, is 1-CC. * This refers to the bare ground surface not covered by crop canopy. This is the adjusted canopy coverage. Canopy coverage, This is the evaporation attenuation coefficient; For the crop transpiration coefficient Under conditions of sufficient water and water stress, it satisfies the following respectively: In the formula, This represents the actual crop evapotranspiration. This represents the stomatal closure coefficient under water stress. The root water absorption coefficient is the volume of water absorbed from a unit volume of soil per unit time.

6. The method for evaluating irrigation water efficiency considering regional water consumption analysis according to claim 3, characterized in that, In step S202, the process of analyzing water consumption is as follows: Using the daily water consumption calculated based on water balance as a reference, after crop sowing, water consumption analysis is performed in conjunction with the effective precipitation calculation results corresponding to each rainfall during the growth period of each crop. When there is no irrigation or rainfall during the growing season, the crop water consumption is allocated to other ET; When there is rainfall during the growing season, the crop's water consumption is prioritized for the allocation of rainfall ET, and any shortfall is allocated to other ET; When there is irrigation during the growing season, and the effective rainfall in the early stage has not been fully allocated, the crop water consumption is allocated in the following order: rainfall ET, irrigation ET, and any shortfall is allocated to other ET. When there is no rainfall during the growing season and only irrigation is available, the crop water consumption is first allocated to irrigation ET, and any remaining water is allocated to other ET.

7. The method for evaluating irrigation water efficiency considering regional water consumption analysis according to claim 1, characterized in that, In step S200, during the water consumption analysis process, rainfall ET allocation is performed, including: After determining the sowing date Total rainfall ET for: Determine the first The daily rainfall ET is: The remaining water demand is determined as follows: Determine to defer to the first Remaining rainfall for the day for: In the formula, For the first Effective precipitation per day For the first The total amount of remaining effective precipitation at the beginning of the day. For the first The amount of precipitation consumed by the day (ET) For the first Daily water consumption For the first Total amount of precipitation (ET) For the first The remaining water consumption for the day.

8. The method for evaluating irrigation water efficiency considering regional water consumption analysis according to claim 1, characterized in that, In step S200, during the water consumption analysis process, irrigation ET allocation is performed, including: Determine the first Total water volume for irrigation of ET on that day for: Determine the first The irrigation ET allocated per day is: The remaining water demand is determined as follows: Determine to defer to the first The remaining irrigation amount for the day is: In the formula, For the first Daily effective precipitation For the first The total amount of remaining effective precipitation at the beginning of the day. For the first The amount of precipitation consumed by the day (ET) For the first The remaining water consumption per day For the first The remaining water demand after the distribution of precipitation For the first Total water volume for irrigation of ET For the first The remaining water demand after irrigation allocation For the first The irrigation ET consumed by the day, For the first The remaining amount after deducting the irrigation ET consumed on that day from the total irrigation water volume for the day is carried over to the next day.

9. The method for evaluating irrigation water efficiency considering regional water consumption analysis according to claim 1, characterized in that, In S300, the regional irrigation ET is: In the formula, For regional irrigation ET, For the first Total irrigation ET for crops For the first in the irrigation area The first crop Irrigation of ET per pixel point, For the first in the region Crop planting area, This represents the total number of pixels within the irrigation area. This represents the total number of crop types.

10. The method for evaluating irrigation water efficiency considering regional water consumption analysis according to claim 1, characterized in that, In S400, the irrigation water efficiency is: : In the formula, For regional irrigation ET, This represents the total irrigation water consumption in the region. For the region number Water intake from each water source This represents the total number of water sources.

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