Adaptive methods for dual risk mitigation of water quality and quantity in agriculture

Abstract

The application discloses an adaptive method for relieving double risks of water quality and water quantity of agriculture, and belongs to the technical field of water resource management.The method is based on a farmland soil nitrogen balance and hydrodynamics coupling model, quantifies a pollution emission list of subdivided sources in the growth process of specific crops, and simulates agricultural pollution dilution water quantity; a crop water requirement model is used to calculate irrigation water consumption of the specific crops in the whole growth period; a water resource loss evaluation module is established to evaluate potential agricultural yield reduction and economic loss caused by water resource shortage; a scenario library of water and fertilizer coordination strategies is constructed to compare the relieving effects of different adaptive strategies on water quantity depletion type and water quality pollution type water resource risks.The application solves the technical problem that it is difficult to simultaneously cope with water quantity risks and water quality risks to develop targeted adaptive strategies, can effectively relieve water resource pressure, improve the sustainability of agricultural production, realize optimal allocation of water resources, and further guarantee the health of an ecological system.

Description

Technical Field

[0001] This invention relates to the field of water resource management technology, specifically to an adaptive method for mitigating the dual risks of agricultural water quality and quantity. Background Technology

[0002] In today's world, the water crisis is becoming increasingly severe, with the dual challenges of water scarcity caused by both quantitative depletion and water pollution being particularly prominent among its complex and diverse manifestations. With population growth and the intensive development of agriculture, more than half of the world's population faces the dual risks of excessive freshwater consumption and pollution. At the same time, many river basins suffer severe water quality degradation due to the influx of nitrogen from agricultural runoff and inadequate wastewater treatment facilities; these threats have a profound impact on the ecological environment and human society.

[0003] Irrigated agriculture, as the world's largest water user sector, consumes over 85% of global freshwater resources and contributes nearly 75% of nitrogen-induced water pollution, making it a core concern in both quantity- and quality-related water scarcity issues. On the one hand, the massive extraction of irrigation water leads to river drying up and a sharp reduction in reservoir storage, intensifying competition with domestic, industrial, and ecological water demands. On the other hand, excessive application of nitrogen fertilizers in irrigated farmland results in large amounts of surplus nitrogen entering adjacent water bodies through runoff or leaching, causing eutrophication and water quality deterioration. This coexistence of "water extraction and consumption" and "water discharge and river pollution" places dual pressure on water resources in terms of both quantity and quality, further exacerbating regional water shortages.

[0004] However, past water scarcity assessments have largely focused on physical water shortages caused by water quantity depletion, while paying insufficient attention to functional water shortages caused by water quality deterioration. Even recent studies that have incorporated water quality factors have failed to clearly distinguish the impacts of consumption and pollution on water scarcity, especially at different population levels. More critically, existing research generally lacks attention to the long-term dynamic evolution of water consumption and pollution scarcity, as well as water risk, particularly the difficulty in accurately quantifying the water and fertilizer requirements of specific crop growth cycles. This makes it impossible to design highly targeted water and fertilizer integration adaptive strategies. This limitation means that when faced with the combined challenges of quantitative water consumption and quality degradation, managers often can only implement simple water allocation within the existing infrastructure and planting structure, making it difficult to quantify and assess the potential benefits of structural adaptation measures such as changing irrigation facilities, adjusting crop planting structures, and implementing nitrogen fertilizer control policies. This hinders the design and implementation of effective, equitable, and regionally targeted water risk mitigation strategies. Summary of the Invention

[0005] The purpose of this invention is to provide an adaptive method for mitigating the dual risks of agricultural water quality and quantity, addressing the problems mentioned in the background art where existing technologies struggle to coordinate both water quantity and water quality risks, and are unable to formulate refined adaptive strategies for specific crop growth cycles. This invention constructs a "water quality-water quantity" coupled model for each crop, enabling precise assessment of water shortage risks and quantifying potential agricultural yield and economic losses caused by water shortages (including water depletion and water pollution). Based on this assessment, this invention can formulate highly targeted adaptive strategies (covering irrigation facility upgrades, planting structure adjustments, and nitrogen management), thereby more effectively allocating water and fertilizer resources, significantly improving irrigation and fertilization efficiency, ensuring stable agricultural production, and minimizing the negative impact of water shortages on the agricultural ecosystem. To achieve the above objectives, this invention provides the following technical solution:

[0006] Adaptive approaches to mitigating the dual risks of agricultural water quality and quantity include:

[0007] Based on the coupled hydrodynamic model of nitrogen budget in farmland soil, the pollution emission inventory of specific sources during the growth process of a particular crop is quantified, and the water consumption for dilution of agricultural pollution is simulated.

[0008] The irrigation water consumption of agricultural irrigation is simulated by using crop water requirement models to calculate the irrigation water consumption during the growth process of specific crops.

[0009] Establish a water resource loss assessment module to conduct risk assessments of agricultural water shortages and evaluate potential agricultural losses caused by water shortages;

[0010] Evaluate the effectiveness of different adaptive strategies in mitigating water resource risks, including upgrading irrigation equipment, reducing nitrogen loss, and optimizing crop planting structure;

[0011] Preferably, a computer simulation is used to break down the pollution emission inventory from various sources during the growth process of multiple crops at a grid scale, and the amount of nitrogen entering the water body for a specific crop j in grid i is calculated based on the principle of farmland nitrogen balance. The formula is as follows:

[0012] ;

[0013] In the formula, Indicates fertilizer; Indicates organic fertilizer; This indicates that straw has been returned to the field. Indicates irrigation water; Indicates biological nitrogen fixation; Indicates atmospheric deposition; Indicates crop harvest; This indicates denitrification in air; It indicates that it remains in the soil;

[0014] The crops include staple crops, other grains, oil crops, sugar crops, starch crops, and other crops;

[0015] Staple crops include wheat, corn, and rice; other grains include barley, rye, millet, and sorghum; oil crops include soybeans, sunflowers, peanuts, oil palm fruit, and castor beans; sugar crops include sugarcane and sugar beets; starch crops include potatoes and cassava; and other crops include legumes, forage grasses, perennial crops, and annual crops.

[0016] Will As a source and sink item The convection-diffusion-dispersion equation is input to simulate the transport and diffusion process of nitrogen in water to determine the water requirement for pollutant dilution. The equation is as follows:

[0017] ;

[0018] In the formula, This indicates nitrogen concentration, expressed in mg / L. This indicates the velocity of water flow, measured in m / s. It represents the effective diffusion coefficient, with units of m² / s, and includes mechanical dispersion and molecular diffusion; Indicates source or sink, unit is mg / (L·s);

[0019] The amount of water used for pollution dilution during the growth of 26 crops was simulated using a computer, and the formula is as follows:

[0020] ;

[0021] In the formula, The amount of nitrogen entering the water body during the growth of crop j in year t is represented by grid i, in kg N / ha, calculated using formulas 1.2 and 1.3. and They are grids The maximum permissible concentration of nitrogen and the natural concentration of nitrogen in water are determined by the World Health Organization and the European Union. The maximum acceptable concentration of nitrogen in water is 10 mg N / L, and the natural concentration of nitrogen in water is about 0.4 mg / L.

[0022] Preferably, the irrigation water consumption during the growth process of a specific crop is calculated using a crop water requirement model to simulate agricultural irrigation water consumption, and the following operations are performed:

[0023] Computer simulations were used to measure the global grid-scale irrigation water consumption of a specific crop, where irrigation water consumption is determined by the portion of crop evapotranspiration that is not effectively replenished by precipitation.

[0024] First, calculate the evapotranspiration of the reference crop. The calculation uses the FAO Penman-Monteith formula, which incorporates various meteorological factors, including air temperature, humidity, wind speed, and solar radiation. The formula is as follows:

[0025] ;

[0026] In the formula, This represents the slope of the saturated water vapor pressure curve, in kPa / ℃. This represents the net radiation emitted by the crop surface, expressed in MJ / (m·d). This represents soil heat flux, expressed in MJ / (m·d). This represents the temperature and humidity constant, with units of kPa / ℃; This represents the average daily temperature at a height of 2m, expressed in °C. This indicates the wind speed at a height of 2m, expressed in m / s. This represents the saturated vapor pressure, expressed in kPa. This represents the actual vapor pressure, expressed in kPa.

[0027] Next, calculate the crop evapotranspiration under standard conditions. Based on reference crop evapotranspiration Introducing crop coefficient Calculate crop evapotranspiration under standard conditions. The formula is as follows:

[0028] ;

[0029] Next, calculate crop evapotranspiration under non-standard conditions. Introducing the water stress coefficient Calculate the actual evapotranspiration of crops under non-standard conditions (water stress). The formula is as follows:

[0030] ;

[0031] ;

[0032] In the formula, St represents the soil moisture content in the root zone on day t; Smax represents the maximum effective water holding capacity in the root zone; p represents the proportion of soil moisture that the crop can extract from the root zone without water stress, which is a function of crop type and potential evapotranspiration.

[0033] Based on soil water balance, the dynamic changes in soil moisture content in the crop root zone are understood by monitoring influent and effluent fluxes. The formula is as follows:

[0034] ;

[0035] In the formula, and express Time and Soil moisture content in the root zone at any given time; Indicates precipitation; Indicates surface runoff; Indicates the amount of irrigation water; Indicates the amount of water rising through the capillary; Indicates soil evaporation; Indicates crop transpiration; This indicates the amount of deep infiltration loss;

[0036] The main sources of water entering the soil include precipitation. Irrigation water Capillary rise Outflow includes surface runoff. Soil evaporation Crop transpiration And deep infiltration losses that will occur if the soil moisture in the root zone exceeds field capacity after heavy rainfall or over-irrigation. Deep infiltration loss equals the maximum field water holding capacity of the soil, i.e., the reservoir capacity minus the current stored water volume. The maximum water holding capacity in the field is closely related to different soil types;

[0037] Finally, based on the fixed irrigated area of ​​the MIRCA2000 dataset, the simulation results are scaled and adjusted using the ratio of the annual irrigated facility area to the reference year for each region, as shown in the following formula:

[0038] ;

[0039] In the formula, Represents a grid Irrigation water consumption adjusted for facility area in year t; This represents the simulated grid. The initial irrigation water consumption in year t; and Representing grids In year t and reference year The area covered by irrigation facilities.

[0040] Preferably, this involves controlling water resource consumption caused by grid-scale water quantity and quality. and With available water resources Combining these factors, we can calculate the water resource pressure caused by water quantity and quality at the grid scale. and The formula is as follows:

[0041] ; ;

[0042] In the formula, and These are agricultural water consumption caused by water quantity and water quality, respectively. and These are industrial water consumption caused by water quantity and water quality, respectively. and These are household water consumption caused by water quantity and water quality, respectively. Indicates total runoff. This represents the environmental flow demand, taking into account the environmental flow demand under different scales and flow conditions to ensure river baseflow, wetland recharge, and critical groundwater depth. The calculation formula is as follows:

[0043] ;

[0044] In the formula, Indicates the total amount of available water; It represents the 25th percentile of total available water; when WSI>1, water resources are being used in an unsustainable manner, leading to the depletion of groundwater or runoff.

[0045] Preferably, a water resource loss assessment module is established to conduct risk assessments of agricultural water shortages, assess potential agricultural losses caused by water shortages, and perform the following operations:

[0046] Based on the water resource stress index, the potential agricultural output loss due to water depletion or water pollution is assessed using the following formula:

[0047] ;

[0048] ;

[0049] ;

[0050] In the formula, , and These respectively represent the risks associated with water quantity shortage, water quality shortage, and overall water resource shortage; , and These represent the potential risk of water resource reduction due to water quantity, water quality, and overall water resource shortage, respectively. They are used to measure the proportion of potential water resource reduction due to water resource shortage, and are converted through the Water Resource Shortage Index (WSI). , and These represent the degree of agricultural dependence on water quantity, water quality, and overall water scarcity, respectively. They are used to measure the percentage of output loss caused by a 1% reduction in water supply, measured by water consumption. The conversion is performed; the output is the agricultural output under the assumption of a sufficient water supply.

[0051] Among them, the water deprivation risk (WDR) ranges from [0,1] and is used to measure the proportion of water use reduction caused by potential water shortage in a region. The higher the degree of water shortage in each region, the greater the possibility of reduced water use. In particular, when WSI exceeds 1, it destroys environmental demand and depletes water resources.

[0052] The WDR function calculates the risk of water deprivation from a probabilistic perspective. For a specific region c, the ratio of available water resources to total water consumption within a given area is represented by a random variable. This indicates that the variable is assumed to follow a log-normal distribution, with the median being the ratio of available water resources to consumption at the regional level, and the standard deviation being σ. The consumption ratio is... The reciprocal of the equation, when water consumption exceeds available levels, is the percentage by which water use needs to be reduced. This ensures that water consumption does not exceed available levels, and the formula is as follows:

[0053] ;

[0054] where , ;

[0055] Among them, water resource dependence (WD) is used to measure the percentage of output loss caused by a 1% reduction in water resource usage per unit. Regions with higher water resource utilization intensity are more sensitive to water resource shortages. Assuming that the maximum possible value of this indicator is 1, at which point water resources are completely irreplaceable and output is reduced according to the proportion of limited water resource supply, the water resource intensity index is adopted and converted from the interval [0, +∞) to the unit water resource dependence index in the interval [0,1) through the following function.

[0056] ;

[0057] In the formula, and Representing water resource dependence and water resource intensity, respectively, parameters control The critical value, after exceeding this critical value It rapidly approaches 1.

[0058] Preferably, the evaluation of the mitigation effects of different adaptive strategies on water resource risks specifically includes constructing and simulating the following hierarchical adaptive scenarios:

[0059] Engineering-based strategies (upgrading irrigation equipment): Based on the crop's suitability for the irrigation system, this includes upgrading surface irrigation to sprinkler systems (IE). dep1 Upgrade surface irrigation to drip irrigation system IE dep2 And upgrading both the ground and sprinkler irrigation systems to drip irrigation systems (IE) dep3 The appropriate irrigation system should be selected based on the suitability of different crops for the irrigation system.

[0060] Management-based strategies (reducing nitrogen loss): Based on the nitrogen loss coefficient under different management measures, setting NL (Nutrition Management Practice) parameters. pol1 Crop Management Measures NL pol2 and the combined implementation of nutrient management and crop management measures NL pol3 ;

[0061] Structural strategy (optimizing crop planting structure): Based on the water intensity of crops within the grid cell, the planting area of ​​crops in high water intensity areas is transferred to low water intensity areas while keeping the total regional yield unchanged. Scenarios with area replacement ratios of 10%, 20%, and 30% are set respectively.

[0062] Comprehensive Optimization Strategy: Combining the above engineering, management, and structural strategies to construct a comprehensive strategy prioritizing water conservation. quan Comb, a comprehensive strategy prioritizing water quality improvement qual The optimal solution for maximizing water resource risk mitigation is found through model iteration.

[0063] Compared with the prior art, the beneficial effects of the present invention are:

[0064] This invention, through global grid-scale analysis of 26 major crops, can accurately simulate irrigation water consumption and pollution dilution water consumption in agricultural production, thereby identifying specific factors leading to water shortages. By quantifying the risks caused by water shortages, it can provide direct decision support for the development of adaptive methods to mitigate water risks, such as upgrading irrigation equipment, reducing nitrogen loss, and optimizing crop planting structures. This can not only alleviate water risks but also improve the sustainability of agricultural production, allocate resources more effectively, optimize agricultural structure, improve water use efficiency, and ensure food security and ecosystem health. Attached Figure Description

[0065] Figure 1 The adaptive optimization flowchart for water resource risk mitigation is shown in the adaptive method for mitigating both agricultural water quality and water quantity risks of the present invention.

[0066] Figure 2 A schematic diagram of the nitrogen cycle in farmland for the adaptive method of mitigating the dual risks of agricultural water quality and quantity according to the present invention;

[0067] Figure 3 This is a schematic diagram of the soil water balance of irrigated crops, illustrating the adaptive method for mitigating both agricultural water quality and quantity risks according to the present invention. Detailed Implementation

[0068] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] To address the existing challenges of effectively coping with both quantitative and qualitative water shortages and water resource risks, please refer to [link / reference]. Figures 1-3 This embodiment provides the following technical solution:

[0070] Adaptive approaches to mitigating the dual risks of agricultural water quality and quantity include:

[0071] Computer simulations were used to analyze the pollution emission inventory from various sources during the growth of multiple crops at a grid scale. Based on the principle of nitrogen balance in farmland, the amount of nitrogen entering the water body for a specific crop j in grid i was calculated. The formula is as follows:

[0072] ;

[0073] In the formula, Indicates fertilizer; Indicates organic fertilizer; This indicates that straw has been returned to the field. Indicates irrigation water; Indicates biological nitrogen fixation; Indicates atmospheric deposition; Indicates crop harvest; This indicates denitrification in air; It indicates that it remains in the soil;

[0074] The crops include staple crops, other grains, oil crops, sugar crops, starch crops, and other crops;

[0075] Staple crops include wheat, corn, and rice; other grains include barley, rye, millet, and sorghum; oil crops include soybeans, sunflowers, peanuts, oil palm fruit, and castor beans; sugar crops include sugarcane and sugar beets; starch crops include potatoes and cassava; and other crops include legumes, forage grasses, perennial crops, and annual crops.

[0076] Will As a source and sink item The convection-diffusion-dispersion equation is input to simulate the transport and diffusion process of nitrogen in water to determine the water requirement for pollutant dilution. The equation is as follows:

[0077] ;

[0078] In the formula, This indicates nitrogen concentration, expressed in mg / L. This indicates the velocity of water flow, measured in m / s. It represents the effective diffusion coefficient, with units of m² / s, and includes mechanical dispersion and molecular diffusion; Indicates source or sink, unit is mg / (L·s);

[0079] The amount of water used for pollution dilution during the growth of 26 crops was simulated using a computer, and the formula is as follows:

[0080] ;

[0081] In the formula, The amount of nitrogen entering the water body during the growth of crop j in year t is represented by grid i, in kg N / ha, calculated using formulas 1.2 and 1.3. and They are grids The maximum permissible concentration of nitrogen and the natural concentration of nitrogen in water are determined by the World Health Organization and the European Union. The maximum acceptable concentration of nitrogen in water is 10 mg N / L, and the natural concentration of nitrogen in water is about 0.4 mg / L.

[0082] Using crop water requirement models, the irrigation water consumption during the growth process of a specific crop is calculated, and agricultural irrigation water consumption is simulated. The following operations are performed:

[0083] Computer simulations were used to measure the global grid-scale irrigation water consumption of a specific crop, where irrigation water consumption is determined by the portion of crop evapotranspiration that is not effectively replenished by precipitation.

[0084] First, calculate the evapotranspiration of the reference crop. The calculation uses the FAO Penman-Monteith formula, which incorporates various meteorological factors, including air temperature, humidity, wind speed, and solar radiation. The formula is as follows:

[0085] ;

[0086] In the formula, This represents the slope of the saturated water vapor pressure curve, in kPa / ℃. This represents the net radiation emitted by the crop surface, expressed in MJ / (m·d). This represents soil heat flux, expressed in MJ / (m·d). This represents the temperature and humidity constant, with units of kPa / ℃; This represents the average daily temperature at a height of 2m, expressed in °C. This indicates the wind speed at a height of 2m, expressed in m / s. This represents the saturated vapor pressure, expressed in kPa. This represents the actual vapor pressure, expressed in kPa.

[0087] Next, calculate the crop evapotranspiration under standard conditions. Based on reference crop evapotranspiration Introducing crop coefficient Calculate crop evapotranspiration under standard conditions. The formula is as follows:

[0088] ;

[0089] Next, calculate crop evapotranspiration under non-standard conditions. Introducing the water stress coefficient Calculate the actual evapotranspiration of crops under non-standard conditions (water stress). The formula is as follows:

[0090] ;

[0091] ;

[0092] In the formula, St represents the soil moisture content in the root zone on day t; Smax represents the maximum effective water holding capacity in the root zone; p represents the proportion of soil moisture that the crop can extract from the root zone without water stress, which is a function of crop type and potential evapotranspiration.

[0093] Based on soil water balance, the dynamic changes in soil moisture content in the crop root zone are understood by monitoring influent and effluent fluxes. The formula is as follows:

[0094] ;

[0095] In the formula, and express Time and Soil moisture content in the root zone at any given time; Indicates precipitation; Indicates surface runoff; Indicates the amount of irrigation water; Indicates the amount of water rising through the capillary; Indicates soil evaporation; Indicates crop transpiration; This indicates the amount of deep infiltration loss;

[0096] The main sources of water entering the soil include precipitation. Irrigation water Capillary rise Outflow includes surface runoff. Soil evaporation Crop transpiration And deep infiltration losses that will occur if the soil moisture in the root zone exceeds field capacity after heavy rainfall or over-irrigation. Deep infiltration loss equals the maximum field water holding capacity of the soil, i.e., the reservoir capacity minus the current stored water volume. The maximum water holding capacity in the field is closely related to different soil types;

[0097] Finally, based on the fixed irrigated area of ​​the MIRCA2000 dataset, the simulation results are scaled and adjusted using the ratio of the annual irrigated facility area to the reference year for each region, as shown in the following formula:

[0098] ;

[0099] In the formula, Represents a grid Irrigation water consumption adjusted for facility area in year t; This represents the simulated grid. The initial irrigation water consumption in year t; and Representing grids In year t and reference year The area covered by irrigation facilities.

[0100] Water consumption caused by grid-scale water quantity and quality and With available water resources Combining these factors, we can calculate the water resource pressure caused by water quantity and quality at the grid scale. and The formula is as follows:

[0101] ; ;

[0102] In the formula, and These are agricultural water consumption caused by water quantity and water quality, respectively. and These are industrial water consumption caused by water quantity and water quality, respectively. and These are household water consumption caused by water quantity and water quality, respectively. Indicates total runoff. This represents the environmental flow demand, taking into account the environmental flow demand under different scales and flow conditions to ensure river baseflow, wetland recharge, and critical groundwater depth. The calculation formula is as follows:

[0103] ;

[0104] In the formula, Indicates the total amount of available water; It represents the 25th percentile of total available water; when WSI>1, water resources are being used in an unsustainable manner, leading to the depletion of groundwater or runoff.

[0105] Establish a water resource loss assessment module to conduct risk assessments of agricultural water shortages, evaluate potential agricultural losses caused by water shortages, and perform the following operations:

[0106] Based on the water resource stress index, the potential agricultural output loss due to water depletion or water pollution is assessed using the following formula:

[0107] ;

[0108] ;

[0109] ;

[0110] In the formula, , and These respectively represent the risks associated with water quantity shortage, water quality shortage, and overall water resource shortage; , and These represent the potential risk of water resource reduction due to water quantity, water quality, and overall water resource shortage, respectively. They are used to measure the proportion of potential water resource reduction due to water resource shortage, and are converted through the Water Resource Shortage Index (WSI). , and These represent the degree of agricultural dependence on water quantity, water quality, and overall water scarcity, respectively. They are used to measure the percentage of output loss caused by a 1% reduction in water supply, measured by water consumption. The conversion is performed; the output is the agricultural output under the assumption of a sufficient water supply.

[0111] Among them, the water deprivation risk (WDR) ranges from [0,1] and is used to measure the proportion of water use reduction caused by potential water shortage in a region. The higher the degree of water shortage in each region, the greater the possibility of reduced water use. In particular, when WSI exceeds 1, it destroys environmental demand and depletes water resources.

[0112] The WDR function calculates the risk of water deprivation from a probabilistic perspective. For a specific region c, the ratio of available water resources to total water consumption within a given area is represented by a random variable. This indicates that the variable is assumed to follow a log-normal distribution, with the median being the ratio of available water resources to consumption at the regional level, and the standard deviation being σ. The consumption ratio is... The reciprocal of the equation, when water consumption exceeds available levels, is the percentage by which water use needs to be reduced. This ensures that water consumption does not exceed available levels, and the formula is as follows:

[0113] ;

[0114] where , ;

[0115] Among them, water resource dependence (WD) is used to measure the percentage of output loss caused by a 1% reduction in water resource usage per unit. Regions with higher water resource utilization intensity are more sensitive to water resource shortages. Assuming that the maximum possible value of this indicator is 1, at which point water resources are completely irreplaceable and output is reduced according to the proportion of limited water resource supply, the water resource intensity index is adopted and converted from the interval [0, +∞) to the unit water resource dependence index in the interval [0,1) through the following function.

[0116] ;

[0117] In the formula, and Representing water resource dependence and water resource intensity, respectively, parameters control The critical value, after exceeding this critical value It rapidly approaches 1.

[0118] To evaluate the effectiveness of different adaptive strategies in mitigating water resource risks, the following hierarchical adaptive scenarios were constructed and simulated:

[0119] Engineering-based strategies (upgrading irrigation equipment): Based on the crop's suitability for the irrigation system, this includes upgrading surface irrigation to sprinkler systems (IE). dep1 Upgrade surface irrigation to drip irrigation system IE dep2And upgrading both the ground and sprinkler irrigation systems to drip irrigation systems (IE) dep3 The appropriate irrigation system should be selected based on the suitability of different crops for the irrigation system.

[0120] Management-based strategies (reducing nitrogen loss): Based on the nitrogen loss coefficient under different management measures, setting NL (Nutrition Management Practice) parameters. pol1 Crop Management Measures NL pol2 and the combined implementation of nutrient management and crop management measures NL pol3 ;

[0121] Structural strategy (optimizing crop planting structure): Based on the water intensity of crops within the grid cell, the planting area of ​​crops in high water intensity areas is transferred to low water intensity areas while keeping the total regional yield unchanged. Scenarios with area replacement ratios of 10%, 20%, and 30% are set respectively.

[0122] Comprehensive Optimization Strategy: Combining the above engineering, management, and structural strategies to construct a comprehensive strategy prioritizing water conservation. quan Comb, a comprehensive strategy prioritizing water quality improvement qual The optimal solution for maximizing water resource risk mitigation is found through model iteration.

[0123] In summary, this invention, by constructing a coupled hydrodynamic model of farmland soil nitrogen budget and a crop water requirement model for specific crops, can accurately identify and distinguish the specific causes of water resource risks arising from water depletion (physical water consumption) and water pollution (functional dilution water requirement) during different crop growth cycles. Based on this, the invention establishes a high-precision gridded dual water resource shortage index of "water quality-water quantity" and a water resource-economic loss assessment module, quantifying the potential yield and economic losses of various crops due to water resource shortages. This allows for the design of highly targeted adaptive strategies (such as upgrading irrigation equipment for high water-consuming crops, optimizing nitrogen management for high-polluting crops, and adjusting planting structures for specific regions). Combining these engineering, management, and structural strategies maximizes risk mitigation benefits with minimal resource input. In conclusion, this invention overcomes the limitations of traditional methods that only focus on macro-level water allocation, providing a novel systematic technical solution for achieving precise water resource management and sustainable utilization throughout the entire growth cycle of specific crops.

[0124] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0125] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An adaptive method for mitigating the dual risks of agricultural water quality and quantity, characterized in that, include: Based on the coupled hydrodynamic model of nitrogen budget in farmland soil, the pollution emission inventory of specific sources during the growth process of a particular crop is quantified, and the water consumption for dilution of agricultural pollution is simulated. The irrigation water consumption of agricultural irrigation is simulated by using crop water requirement models to calculate the irrigation water consumption during the growth process of specific crops. Establish a water resource loss assessment module to conduct risk assessments of agricultural water shortages and evaluate potential agricultural losses caused by water shortages; Evaluate the effectiveness of different adaptive strategies in mitigating water resource risks, including upgrading irrigation equipment, reducing nitrogen loss, and optimizing crop planting structure; Perform the following operations: Computer simulations were used to analyze the pollution emission inventory from various sources during the growth of multiple crops at a grid scale. Based on the principle of nitrogen balance in farmland, the amount of nitrogen entering the water body for a specific crop j in grid i was calculated. The formula is as follows: ； In the formula, Indicates fertilizer; Indicates organic fertilizer; This indicates that straw has been returned to the field. Indicates irrigation water; Indicates biological nitrogen fixation; Indicates atmospheric deposition; Indicates crop harvest; This indicates denitrification in air; It indicates that it remains in the soil; The crops include staple crops, other grains, oil crops, sugar crops, starch crops, and other crops; Staple crops include wheat, corn, and rice; other grains include barley, rye, millet, and sorghum; oil crops include soybeans, sunflowers, peanuts, oil palm fruit, and castor beans; sugar crops include sugarcane and sugar beets; starch crops include potatoes and cassava; and other crops include legumes, forage grasses, perennial crops, and annual crops. Will As a source and sink item The convection-diffusion-dispersion equation is input to simulate the transport and diffusion process of nitrogen in water to determine the water requirement for pollutant dilution. The equation is as follows: ； In the formula, This indicates nitrogen concentration, expressed in mg / L. This indicates the velocity of water flow, measured in m / s. It represents the effective diffusion coefficient, with units of m² / s, and includes mechanical dispersion and molecular diffusion; Indicates source or sink, unit is mg / (L·s); The amount of water used for pollution dilution during the growth of 26 crops was simulated using a computer, and the formula is as follows: ； In the formula, The amount of nitrogen entering the water body during the growth of crop j in year t is represented by grid i, in kgN / ha, calculated using formulas 1.2 and 1.

3. and They are grids The maximum permissible concentration of nitrogen and the natural concentration of nitrogen in water are determined by the World Health Organization and the European Union. The maximum acceptable concentration of nitrogen in water is 10 mg N / L, and the natural concentration of nitrogen in water is about 0.4 mg / L.

2. The adaptive method for mitigating the dual risks of agricultural water quality and quantity according to claim 1, characterized in that, Using crop water requirement models, the irrigation water consumption during the growth process of a specific crop is calculated, and agricultural irrigation water consumption is simulated. The following operations are performed: Computer simulations were used to measure the global grid-scale irrigation water consumption of a specific crop, where irrigation water consumption is determined by the portion of crop evapotranspiration that is not effectively replenished by precipitation. First, calculate the evapotranspiration of the reference crop. The calculation uses the FAO Penman-Monteith formula, which incorporates various meteorological factors, including air temperature, humidity, wind speed, and solar radiation. The formula is as follows: ； In the formula, This represents the slope of the saturated water vapor pressure curve, in kPa / ℃. This represents the net radiation emitted by the crop surface, expressed in MJ / (m·d). This represents soil heat flux, expressed in MJ / (m·d). This represents the temperature and humidity constant, with units of kPa / ℃; This represents the average daily temperature at a height of 2m, expressed in °C. This indicates the wind speed at a height of 2m, expressed in m / s. This represents the saturated vapor pressure, expressed in kPa. This represents the actual vapor pressure, expressed in kPa. Next, calculate the crop evapotranspiration under standard conditions. Based on reference crop evapotranspiration Introducing crop coefficient Calculate crop evapotranspiration under standard conditions. The formula is as follows: ； Next, calculate crop evapotranspiration under non-standard conditions. Introducing the water stress coefficient Calculate the actual evapotranspiration of crops under non-standard conditions (water stress). The formula is as follows: ； ； In the formula, St represents the soil moisture content in the root zone on day t; Smax represents the maximum effective water holding capacity in the root zone; p represents the proportion of soil moisture that the crop can extract from the root zone without water stress, which is a function of crop type and potential evapotranspiration. Based on soil water balance, the dynamic changes in soil moisture content in the crop root zone are understood by monitoring influent and effluent fluxes. The formula is as follows: ； In the formula, and express Time and Soil moisture content in the root zone at any given time; Indicates precipitation; Indicates surface runoff; Indicates the amount of irrigation water; Indicates the amount of water rising through the capillary; Indicates soil evaporation; Indicates crop transpiration; This indicates the amount of deep infiltration loss; The main sources of water entering the soil include precipitation. Irrigation water Capillary rise Outflow includes surface runoff. Soil evaporation Crop transpiration And deep infiltration losses that will occur if the soil moisture in the root zone exceeds field capacity after heavy rainfall or over-irrigation. Deep infiltration loss equals the maximum field water holding capacity of the soil, i.e., the reservoir capacity minus the current stored water volume. The maximum water holding capacity in the field is closely related to different soil types; Finally, based on the fixed irrigated area of ​​the MIRCA2000 dataset, the simulation results are scaled and adjusted using the ratio of the annual irrigated facility area to the reference year for each region, as shown in the following formula: ； In the formula, Represents grid Irrigation water consumption adjusted for facility area in year t; This represents the simulated grid. The initial irrigation water consumption in year t; and Representing grids In year t and reference year The area covered by irrigation facilities.

3. The adaptive method for mitigating the dual risks of agricultural water quality and quantity according to claim 2, characterized in that, Water consumption caused by grid-scale water quantity and quality and With available water resources Combining these factors, we can calculate the water resource pressure caused by water quantity and quality at the grid scale. and The formula is as follows: ； ； In the formula, and These are agricultural water consumption caused by water quantity and water quality, respectively. and These are industrial water consumption caused by water quantity and water quality, respectively. and These are household water consumption caused by water quantity and water quality, respectively. Indicates total runoff. This represents the environmental flow demand, taking into account the environmental flow demand under different scales and flow conditions to ensure river baseflow, wetland recharge, and critical groundwater depth. The calculation formula is as follows: ； In the formula, Indicates the total amount of available water; It represents the 25th percentile of total available water; when WSI>1, water resources are being used in an unsustainable manner, leading to the depletion of groundwater or runoff.

4. The adaptive method for mitigating the dual risks of agricultural water quality and quantity according to claim 3, characterized in that, Establish a water resource loss assessment module to conduct risk assessments of agricultural water shortages, evaluate potential agricultural losses caused by water shortages, and perform the following operations: Based on the water resource stress index, the potential agricultural output loss due to water depletion or water pollution is assessed using the following formula: ； ； ； In the formula, , and These respectively represent the risks associated with water quantity shortage, water quality shortage, and overall water resource shortage; , and These represent the potential risk of water resource reduction due to water quantity, water quality, and overall water resource shortage, respectively. They are used to measure the proportion of potential water resource reduction due to water resource shortage, and are converted through the Water Resource Shortage Index (WSI). , and These represent the degree of agricultural dependence on water quantity, water quality, and overall water scarcity, respectively. They are used to measure the percentage of output loss caused by a 1% reduction in water supply, measured by water consumption. The conversion is performed; the output is the agricultural output under the assumption of a sufficient water supply. Among them, the water deprivation risk (WDR) ranges from [0,1] and is used to measure the proportion of water use reduction caused by potential water shortage in a region. The higher the degree of water shortage in each region, the greater the possibility of reduced water use. In particular, when WSI exceeds 1, it destroys environmental demand and depletes water resources. The WDR function calculates the risk of water deprivation from a probabilistic perspective. For a specific region c, the ratio of available water resources to total water consumption within a given area is represented by a random variable. This indicates that the variable is assumed to follow a log-normal distribution, with the median being the ratio of available water resources to consumption at the regional level, and the standard deviation being σ. The consumption ratio is... The reciprocal of the equation, when water consumption exceeds available levels, is the percentage by which water use needs to be reduced. This ensures that water consumption does not exceed available levels, and the formula is as follows: ； where , ; Among them, water resource dependence (WD) is used to measure the percentage of output loss caused by a 1% reduction in water resource usage per unit. Regions with higher water resource utilization intensity are more sensitive to water resource shortages. Assuming that the maximum possible value of this indicator is 1, at which point water resources are completely irreplaceable and output is reduced according to the proportion of limited water resource supply, the water resource intensity index is adopted and converted from the interval [0, +∞) to the unit water resource dependence index in the interval [0,1) through the following function. ； In the formula, and Representing water resource dependence and water resource intensity, respectively, parameters control The critical value, after exceeding this critical value It rapidly approaches 1.

5. The adaptive method for mitigating the dual risks of agricultural water quality and quantity according to claim 4, characterized in that, To evaluate the effectiveness of different adaptive strategies in mitigating water resource risks, the following hierarchical adaptive scenarios were constructed and simulated: Engineering-based strategies (upgrading irrigation equipment): Based on the crop's suitability for the irrigation system, this includes upgrading surface irrigation to sprinkler systems (IE). dep1 Upgrade surface irrigation to drip irrigation system IE dep2 And upgrading both the ground and sprinkler irrigation systems to drip irrigation systems (IE) dep3 The appropriate irrigation system should be selected based on the suitability of different crops for the irrigation system. Management-based strategies (reducing nitrogen loss): Based on the nitrogen loss coefficient under different management measures, setting NL (Nutrition Management Practice) parameters. pol1 Crop Management Measures NL pol2 and the combined implementation of nutrient management and crop management measures NL pol3 ; Structural strategy (optimizing crop planting structure): Based on the water intensity of crops within the grid cell, the planting area of ​​crops in high water intensity areas is transferred to low water intensity areas while keeping the total regional yield unchanged. Scenarios with area replacement ratios of 10%, 20%, and 30% are set respectively. Comprehensive Optimization Strategy: Combining the above engineering, management, and structural strategies to construct a comprehensive strategy prioritizing water conservation. quan Comb, a comprehensive strategy prioritizing water quality improvement qual The optimal solution for maximizing water resource risk mitigation is found through model iteration.

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