Nitrogen reduction potential evaluation and regional grading control method and system for small and micro wetlands in rice region

Abstract

According to the rice area small and micro wetland nitrogen reduction potential evaluation and area grading control method and system, firstly, relevant data are collected, nitrogen reduction potential evaluation indexes of rice area small and micro wetlands are calculated, and the nitrogen reduction potential evaluation indexes comprise the nitrogen removal rate, the nitrogen removal amount and the nitrogen removal economic benefits. Then, based on the nitrogen removal amount of the small and micro wetlands in the rice area, the small and micro wetlands in different areas in the rice area are subjected to graded management and control in combination with the rice field nitrogen loads in all the areas in the rice area. The system evaluates the nitrogen reduction potential of the small and micro wetlands, fully considers biochemical factors having important influence on nitrogen removal, such as large aquatic plants, temperature, nitrogen concentration and the like, provides more reliable nitrogen reduction efficiency prediction for the actual management of the small and micro wetlands in the rice area, improves the accuracy and applicability of the evaluation model, and has good application prospects. And hierarchical management and control are carried out according to regional characteristics, so that scientific formulation and accurate implementation of protection and management measures of the small and micro wetlands in the rice area are facilitated.

Description

Technical Field

[0001] This invention belongs to the field of ecological environment assessment, specifically involving a method and system for assessing the nitrogen reduction potential of small wetlands in rice-growing areas and for regional hierarchical management. Background Technology

[0002] Paddy fields are a significant non-point source of nitrogen pollution globally, posing a serious threat to the water quality of surrounding water bodies. Surface runoff is one of the main pathways for nitrogen loss from paddy fields, and the lost nitrogen typically enters receiving water bodies after passing through multiple small wetlands. These small wetlands can effectively reduce nitrogen load through vegetation absorption, sediment adsorption, and microbial community-mediated nitrification and denitrification. In recent years, with accelerated urbanization and intensive agricultural development, a large number of small wetlands have been filled in or converted into farmland, resulting in a significant reduction in their area. Especially in rice-growing areas, the protection and restoration of small wetlands face multiple pressures. Therefore, systematically assessing the nitrogen reduction potential of small wetlands and implementing tiered management based on the characteristics of different regions is helpful for scientifically formulating and precisely implementing protection and management measures for small wetlands in rice-growing areas.

[0003] Nitrogen cycling microorganisms are the main driving force for nitrogen removal in wetlands. However, existing wetland nitrogen reduction assessment models mostly consider physical indicators of wetlands, such as area and hydraulic retention time, without fully taking into account biochemical factors that have a significant impact on nitrogen cycling microorganisms, leading to inaccurate nitrogen reduction assessments. In addition, existing research lacks methodological support for the hierarchical management of small wetlands in rice-growing areas. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the existing technology by providing a method and system for assessing the nitrogen reduction potential and regional hierarchical management of small wetlands in rice-growing areas.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] In a first aspect, this invention proposes a method for assessing the nitrogen reduction potential of small wetlands in rice-growing areas, comprising:

[0007] Collect relevant data and calculate the nitrogen reduction potential assessment index for small wetlands in rice-growing areas, including nitrogen removal rate;

[0008] The nitrogen removal rate is calculated using the following formula:

[0009] ;

[0010] ;

[0011] In the above formula, Small wetlands nitrogen removal rate Small wetlands The nitrogen removal rate constant, Small wetlands Hydraulic residence time, Small wetlands vegetation coverage Small wetlands The influent nitrogen concentration, Small wetlands The temperature.

[0012] The nitrogen reduction potential assessment indicators also include nitrogen removal volume and the economic benefits of nitrogen removal;

[0013] The nitrogen removal rate is calculated using the following formula:

[0014] ;

[0015] The economic benefits of nitrogen removal are calculated using the following formula:

[0016] ;

[0017] In the above formula, Small wetlands nitrogen removal rate Small wetlands Nitrogen load in paddy field runoff, Small wetlands nitrogen removal rate, Small wetlands The economic benefits of nitrogen removal The nitrogen concentration in the influent of the wastewater treatment plant. This refers to the nitrogen concentration in the effluent from a wastewater treatment plant.

[0018] Secondly, this invention proposes a method for the hierarchical management and control of small wetlands in rice-growing areas, including:

[0019] Based on the nitrogen removal capacity of small wetlands in rice-growing areas, and combined with the nitrogen load of paddy fields in different regions within the rice-growing areas, small wetlands in different areas of the rice-growing areas are subject to graded management and control, including:

[0020] like ,and Then determine the area within the rice-growing region. It belongs to Category 1 key restoration area, and the management strategy of appropriately increasing the area of ​​small and micro wetlands is adopted;

[0021] like ,and Then determine the area within the rice-growing region. It belongs to the Class 2 optimization and efficiency enhancement area, and adopts the management strategy of increasing the vegetation coverage of small wetlands;

[0022] like ,and Then determine the area within the rice-growing region. It belongs to Class 3 conventional monitoring area, and adopts the monitoring of nitrogen load in paddy fields. When the nitrogen load increases, the wetland restoration management strategy is implemented.

[0023] like ,and Then determine the area within the rice-growing region. It belongs to Class 4 ecological protection area, and adopts the management strategy of prohibiting landfill and encroachment on small wetlands and maintaining the existing area of ​​small wetlands;

[0024] In the above formula, Within the rice-growing area Nitrogen load in paddy field runoff, Within the rice-growing area The amount of nitrogen removed, i.e., the area The total nitrogen removal of all small and micro wetlands in the region. The number of regions to be divided within the rice-growing area;

[0025] in, The calculation method includes: first calculating the nitrogen removal rate according to the method described in claim 1, and then calculating the nitrogen removal amount based on the nitrogen removal rate.

[0026] The specific management strategy of appropriately increasing the area of ​​small wetlands includes:

[0027] Determine whether the vegetation cover of the small wetlands in the key restoration area of ​​Category 1 is less than 0.5. If it is not less than 0.5, directly increase the area of ​​the small wetlands. If it is less than 0.5, first increase the vegetation cover of the small wetlands to 0.5, and calculate the nitrogen removal amount of the small wetlands after the increase in vegetation cover, and determine the nitrogen removal amount at this time. If the condition is met, the repair work will stop; if not, the area of ​​the small wetland will be increased.

[0028] The required increase in the area of ​​small wetlands is calculated using the following formula:

[0029] ;

[0030] ;

[0031] ;

[0032] ;

[0033] In the above formula, Key restoration area The area of ​​small wetlands that need to be increased Key restoration area The total area of ​​small wetlands will be increased. Key restoration area The existing area of ​​small wetlands, Key restoration area The hydraulic retention time of all small wetlands after increasing their area. Key restoration area Average flow rate of paddy field drainage, Key restoration area Depth of small wetlands Key restoration area The area of ​​rice paddies, Key restoration area Nitrogen removal rate of all small wetlands after increasing the area of ​​small wetlands. Key restoration area The nitrogen removal rate constant after increasing the vegetation cover of small wetlands to 0.5. The number of regions to be divided in the rice-growing area. Within the rice-growing area Nitrogen removal load of small wetlands Key restoration area Nitrogen load in paddy fields.

[0034] Thirdly, this invention proposes a nitrogen reduction potential assessment system for small wetlands in rice-growing areas, which is used to collect relevant data and calculate nitrogen reduction potential assessment indicators for small wetlands in rice-growing areas, including a nitrogen removal rate calculation unit.

[0035] The nitrogen removal rate calculation unit is used to calculate the nitrogen removal rate using the following formula:

[0036] ;

[0037] ;

[0038] In the above formula, Small wetlands nitrogen removal rate Small wetlands The nitrogen removal rate constant, Small wetlands Hydraulic residence time, Small wetlands vegetation coverage Small wetlands The influent nitrogen concentration, Small wetlands The temperature.

[0039] The system also includes a nitrogen removal calculation unit and a nitrogen removal economic benefit calculation unit;

[0040] The nitrogen removal calculation unit is used to calculate the nitrogen removal amount using the following formula:

[0041] ;

[0042] The nitrogen removal economic benefit calculation unit is used to calculate the nitrogen removal economic benefit using the following formula:

[0043] ;

[0044] In the above formula, Small wetlands nitrogen removal rate Small wetlands Nitrogen load in paddy field runoff, Small wetlands nitrogen removal rate, Small wetlands The economic benefits of nitrogen removal The nitrogen concentration in the influent of the wastewater treatment plant. This refers to the nitrogen concentration in the effluent from a wastewater treatment plant.

[0045] Fourthly, this invention proposes a regional hierarchical management system for small wetlands in rice-growing areas, which is used to hierarchically manage small wetlands in different areas of rice-growing areas based on the nitrogen removal of small wetlands in rice-growing areas and the nitrogen load of paddy fields in various areas of rice-growing areas. The system includes a nitrogen removal calculation unit, a regional hierarchical unit, and a hierarchical management unit.

[0046] The nitrogen removal calculation unit is used to calculate the nitrogen removal amount using the following formula:

[0047] ;

[0048] ;

[0049] ;

[0050] In the above formula, Small wetlands nitrogen removal rate Small wetlands Nitrogen load in paddy field runoff, Small wetlands nitrogen removal rate, Small wetlands The nitrogen removal rate constant, Small wetlands Hydraulic residence time, Small wetlands vegetation coverage Small wetlands The influent nitrogen concentration, Small wetlands Temperature;

[0051] The regional classification unit is used to determine the type of each region within the rice-growing area according to the following principles:

[0052] like ,and Then determine the area within the rice-growing region. It belongs to Category 1 key restoration area;

[0053] like ,and Then determine the area within the rice-growing region. It belongs to Category 2 optimization and efficiency enhancement area;

[0054] like ,and Then determine the area within the rice-growing region. It belongs to Class 3 routine monitoring area;

[0055] like ,and Then determine the area within the rice-growing region. It belongs to Class 4 ecological protection area;

[0056] In the above formula, Within the rice-growing area Nitrogen load in paddy field runoff, Within the rice-growing area The amount of nitrogen removed, i.e., the area The total nitrogen removal of all small and micro wetlands in the region. The number of regions to be divided within the rice-growing area;

[0057] The hierarchical control unit performs regional control based on the following strategies:

[0058] For Class 1 key restoration areas, a management strategy of appropriately increasing the area of ​​small and micro wetlands will be adopted;

[0059] For the Class 2 optimization and efficiency enhancement zone, a control strategy of increasing the vegetation coverage of small wetlands is adopted;

[0060] For Class 3 conventional monitoring areas, paddy field nitrogen load monitoring is adopted, and wetland restoration management strategies are implemented when nitrogen load increases.

[0061] For Class 4 ecological protection areas, a management strategy is adopted that prohibits the filling and encroachment of small wetlands and maintains the existing area of ​​small wetlands.

[0062] The specific management strategy of appropriately increasing the area of ​​small wetlands includes:

[0063] Determine whether the vegetation cover of the small wetlands in the key restoration area of ​​Category 1 is less than 0.5. If it is not less than 0.5, directly increase the area of ​​the small wetlands. If it is less than 0.5, first increase the vegetation cover of the small wetlands to 0.5, and calculate the nitrogen removal amount of the small wetlands after the increase in vegetation cover, and determine the nitrogen removal amount at this time. If the condition is met, the repair work will stop; if not, the area of ​​the small wetland will be increased.

[0064] The required increase in the area of ​​small wetlands is calculated using the following formula:

[0065] ;

[0066] ;

[0067] ;

[0068] ;

[0069] In the above formula, Key restoration area The area of ​​small wetlands that need to be increased Key restoration area The total area of ​​small wetlands will be increased. Key restoration area The existing area of ​​small wetlands, Key restoration area The hydraulic retention time of all small wetlands after increasing their area. Key restoration area Average flow rate of paddy field drainage, Key restoration area Depth of small wetlands Key restoration area The area of ​​rice paddies, Key restoration area Nitrogen removal rate of all small wetlands after increasing the area of ​​small wetlands. Key restoration area The nitrogen removal rate constant after increasing the vegetation cover of small wetlands to 0.5. The number of regions to be divided in the rice-growing area. Within the rice-growing area Nitrogen removal load of small wetlands Key restoration area Nitrogen load in paddy fields.

[0070] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0071] 1. This invention proposes a method for assessing the nitrogen reduction potential of small wetlands in rice-growing areas. This method collects relevant data and calculates assessment indicators for the nitrogen reduction potential of small wetlands in rice-growing areas. These indicators include nitrogen removal rate, nitrogen removal amount, and nitrogen removal economic benefits. On one hand, this method uses vegetation cover, temperature, and nitrogen concentration of the small wetland to determine the nitrogen removal rate constant, fully considering biological factors that significantly influence nitrogen removal, such as large aquatic plants, temperature, and nitrogen concentration. This provides a more reliable prediction of nitrogen reduction efficiency for the actual management of small wetlands in rice-growing areas, overcoming the shortcomings of existing models in terms of accuracy and applicability. On the other hand, this method systematically assesses the nitrogen reduction potential of small wetlands using nitrogen removal rate, nitrogen removal amount, and nitrogen removal economic benefits. The nitrogen removal rate constant reflects the nitrogen removal efficiency of the wetland ecosystem; the nitrogen removal amount focuses on the absolute amount of nitrogen actually removed, reflecting the actual contribution of the wetland; and the nitrogen removal economic benefits assess the actual costs and benefits of wetland management and restoration from an economic perspective. By integrating these three nitrogen reduction potential assessment indicators, the bias of a single dimension can be avoided, allowing for a more comprehensive assessment of the nitrogen reduction potential of small wetlands.

[0072] 2. This invention proposes a hierarchical management method for small wetlands in rice-growing areas. This method, based on the nitrogen removal capacity of these wetlands and the nitrogen load of paddy fields in different areas within the rice-growing region, implements hierarchical management of small wetlands in different regions. Implementing hierarchical management based on regional characteristics helps to scientifically formulate and accurately implement protection and management measures for small wetlands in rice-growing areas. Attached Figure Description

[0073] Figure 1 This is an overall flowchart of the method described in this invention.

[0074] Figure 2 This is a map showing the nitrogen removal rate constant, nitrogen removal rate, nitrogen removal amount, and hierarchical control for various cities in China's major rice-growing areas.

[0075] Figure 3 This is a structural diagram of the system described in Example 3.

[0076] Figure 4 This is a structural diagram of the system described in Example 4. Detailed Implementation

[0077] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0078] This invention proposes a method and system for assessing the nitrogen reduction potential of small wetlands in rice-growing areas and for regional hierarchical management, such as... Figure 1As shown, environmental and geospatial data, as well as wastewater treatment efficiency data from wastewater treatment plants, were acquired from paddy fields and small wetlands in rice-growing areas. Based on this data, the nitrogen removal rate, nitrogen removal volume, and economic benefits of nitrogen removal in small wetlands were determined, and the nitrogen reduction potential of small wetlands in rice-growing areas was systematically assessed. Finally, tiered management based on regional characteristics was implemented, which helps to scientifically formulate and accurately implement protection and management measures for small wetlands in rice-growing areas.

[0079] Example 1:

[0080] A method for assessing the nitrogen reduction potential of small wetlands in rice-growing areas is carried out in the following steps:

[0081] 1. Collect environmental data, geospatial data, and wastewater treatment efficiency data of paddy fields and small wetlands in various cities within the rice-growing region.

[0082] Environmental data for paddy fields and small wetlands within the rice-growing area include paddy field runoff, paddy field runoff nitrogen load, small wetland temperature, small wetland vegetation cover, and small wetland influent nitrogen concentration. Paddy field runoff was estimated using total paddy field drainage and the number of days in the growing season, while paddy field drainage was simulated using the WQQM-PIDU model. Paddy field runoff nitrogen load was estimated by multiplying paddy field drainage by the corresponding runoff nitrogen concentration, which was estimated using the relationship between nitrogen concentration and fertilizer application, soil pH, and soil organic matter. The coverage of large aquatic plants in small wetlands was determined visually using 1-meter resolution Gaofen-2 remote sensing imagery. Paddy field runoff nitrogen concentration was used as the influent nitrogen concentration for small wetlands.

[0083] Geospatial data on paddy fields and small wetlands within the rice-growing area includes their spatial distribution, area, and depth. Spatial distribution data for paddy fields were obtained from multi-period land use / land cover remote sensing monitoring data in China. Spatial distribution and area data for small wetlands were acquired from 2-meter resolution RGB imagery of Google Earth from May to September 2018. Depth data for small wetlands was estimated using an empirical formula relating to their area size.

[0084] Wastewater treatment plant efficiency data includes nitrogen concentrations in the influent and effluent, as well as the unit cost of wastewater treatment. The data are derived from results reported in the literature.

[0085] 2. Based on the collected relevant data, calculate the nitrogen reduction potential assessment indicators for small wetlands in rice-growing areas;

[0086] The nitrogen reduction potential assessment indicators for small wetlands in rice-growing areas include nitrogen removal rate, nitrogen removal amount, and economic benefits of nitrogen removal. Considering all three indicators simultaneously avoids bias from a single dimension. The nitrogen removal rate constant measures the nitrogen removal capacity of a small wetland over a specific time period, reflecting the nitrogen removal efficiency of the wetland ecosystem and demonstrating the biogeochemical processes of the wetland. Nitrogen removal amount focuses on the absolute amount of nitrogen actually removed, reflecting the actual contribution of the wetland. Even if a wetland has a high nitrogen removal rate, its overall nitrogen removal amount may be low if its area is small or its nitrogen load is low. Nitrogen removal amount allows for a better quantification of the wetland's management benefits. The economic benefits of nitrogen removal can be used to assess the actual costs and benefits of wetland management and restoration, reflecting the management value of the wetland. Combining these three factors allows for a more comprehensive assessment of the nitrogen reduction potential of small wetlands.

[0087] In addition, environmental factors such as temperature, nitrogen concentration, and macrophytes are important influencing factors on the nitrogen cycle microbial community in small wetlands, playing a decisive role in their nitrogen reduction efficiency. Macrophytes, in particular, serve as a key interface between the nitrogen source and the receiving water body, playing a crucial role in promoting denitrification and nitrogen reduction through direct nitrogen absorption and synergistic interactions with microorganisms. By comprehensively considering key environmental factors affecting microorganisms, such as macrophyte cover, temperature, and nitrogen concentration, a nitrogen removal rate constant model can be constructed, providing a more reliable prediction of nitrogen reduction efficiency for the practical management of small wetlands.

[0088] The nitrogen removal rate is calculated using the following formula:

[0089] ;

[0090] ;

[0091] ;

[0092] The nitrogen removal rate is calculated using the following formula:

[0093] ;

[0094] The economic benefits of nitrogen removal are calculated using the following formula:

[0095] ;

[0096] In the above formula, Small wetlands nitrogen removal rate , Small wetlands nitrogen removal rate constant , Small wetlands Hydraulic residence time , Small wetlands vegetation coverage Small wetlands influent nitrogen concentration , Small wetlands temperature , For small wetlands area , Small wetlands depth , Average runoff from paddy fields , Small wetlands nitrogen removal , Small wetlands Nitrogen load in paddy field runoff , Small wetlands economic benefits of nitrogen removal , Nitrogen concentration in the influent of the wastewater treatment plant , Nitrogen concentration in wastewater effluent from wastewater treatment plants .

[0097] The nitrogen removal rate constant of small wetlands in major rice-growing areas of China was calculated to be: Nitrogen removal rate Nitrogen removal amount is The economic benefits of nitrogen removal per thousand tons are 100 million yuan.

[0098] Example 2:

[0099] A method for the graded management and control of small wetlands in rice-growing areas is carried out in the following steps:

[0100] 1. Based on the nitrogen removal capacity of small wetlands in rice-growing areas, and combined with the nitrogen load of paddy fields in different areas of the rice-growing area, small wetlands in different areas of the rice-growing area are classified and managed.

[0101] like ,and If so, the area belongs to Category 1 key restoration area;

[0102] like ,and If so, then this area belongs to the Class 2 optimization and efficiency enhancement zone;

[0103] like ,and If so, the area belongs to Class 3 routine monitoring area;

[0104] like ,and If so, the area belongs to Class 4 ecological protection zone;

[0105] In the above formula, Within the rice-growing area Nitrogen load in paddy field runoff , Within the rice-growing area nitrogen removal That is, the region The total nitrogen removal of all small and micro wetlands in the region. The number of regions to be divided in the rice-growing area.

[0106] in, The calculation method includes: first, calculating the nitrogen removal rate based on a method for assessing the nitrogen reduction potential of small wetlands in rice-growing areas, and then calculating the amount of nitrogen removed based on the nitrogen removal rate.

[0107] Nitrogen removal rate constant, nitrogen removal rate, nitrogen removal amount, and hierarchical management in major rice-growing cities in China, as follows: Figure 2 As shown, in China's major rice-growing areas, 16.58% of the regions belong to Category 1 key restoration areas, where the area of ​​small wetlands will be appropriately increased to optimize the wetland ecological structure and enhance the nitrogen reduction capacity of small wetlands. 26.60% of the regions belong to Category 2 optimization and efficiency enhancement areas, where the wetland ecological structure will be optimized to increase the nitrogen reduction capacity of small wetlands. 49.23% of the regions belong to Category 3 routine monitoring areas, where nitrogen load in paddy fields will be monitored, and necessary restoration can be implemented when nitrogen load increases. 5.91% of the regions belong to Category 4 ecological protection areas, where the filling and encroachment of small wetlands are prohibited, and the existing area of ​​small wetlands will be maintained.

[0108] Specifically, for Category 1 key restoration areas, the specific implementation steps for appropriately increasing the area of ​​small wetlands, optimizing the wetland ecological structure, and enhancing the nitrogen reduction capacity of small wetlands include:

[0109] First, determine whether the vegetation cover of small wetlands in the Class 1 key restoration area is less than 0.5:

[0110] If the value is less than 0.5, first increase the vegetation cover of the small wetland to 0.5, and calculate the nitrogen removal amount of the small wetland after increasing the vegetation cover. Then determine the nitrogen removal amount at this time. If the condition is met, the repair work will stop; if not, the area of ​​the small wetland will be increased.

[0111] If it is not less than, then the area of ​​small wetlands will be increased directly.

[0112] The required increase in the area of ​​small wetlands is calculated using the following formula:

[0113] ;

[0114] ;

[0115] ;

[0116] ;

[0117] In the above formula, Key restoration area The area of ​​small wetlands that need to be increased , Key restoration area Increased total area of ​​small wetlands , Key restoration area Existing small wetland area , Key restoration area Hydraulic retention time of all small wetlands after increasing their area , Key restoration area Average flow rate of paddy field drainage , Key restoration area Depth of small wetlands Key restoration area Rice paddy area , Key restoration area Nitrogen removal rate of all small wetlands after increasing the area of ​​small wetlands. Key restoration area The nitrogen removal rate constant after increasing the vegetation cover of small wetlands to 0.5. The number of regions to be divided in the rice-growing area. Within the rice-growing area Nitrogen removal load of small wetlands Key restoration area Nitrogen load in paddy fields.

[0118] This embodiment calculates that, in key restoration areas of small and micro wetlands in major rice-growing regions of China, an additional 118.68 hectares of small and micro wetland area needs to be added after increasing the ratio of small and micro wetlands to 0.5. .

[0119] Example 3:

[0120] like Figure 3As shown, a nitrogen reduction potential assessment system for small wetlands in rice-growing areas is used to collect relevant data and calculate nitrogen reduction potential assessment indicators for small wetlands in rice-growing areas, including a nitrogen removal rate calculation unit, a nitrogen removal amount calculation unit, and a nitrogen removal economic benefit calculation unit.

[0121] The nitrogen removal rate calculation unit is used to calculate the nitrogen removal rate using the following formula:

[0122] ;

[0123] ;

[0124] In the above formula, Small wetlands nitrogen removal rate Small wetlands The nitrogen removal rate constant, Small wetlands Hydraulic residence time, Small wetlands vegetation coverage Small wetlands The influent nitrogen concentration, Small wetlands The temperature.

[0125] The nitrogen removal calculation unit is used to calculate the nitrogen removal amount using the following formula:

[0126] ;

[0127] The nitrogen removal economic benefit calculation unit is used to calculate the nitrogen removal economic benefit using the following formula:

[0128] ;

[0129] In the above formula, Small wetlands nitrogen removal rate Small wetlands Nitrogen load in paddy field runoff, Small wetlands nitrogen removal rate Small wetlands The economic benefits of nitrogen removal The nitrogen concentration in the influent of the wastewater treatment plant. This refers to the nitrogen concentration in the effluent from a wastewater treatment plant.

[0130] Example 4:

[0131] like Figure 4As shown, a regional hierarchical management system for small wetlands in rice-growing areas is used to hierarchically manage small wetlands in different areas of rice-growing areas based on the nitrogen removal amount of small wetlands in rice-growing areas and the nitrogen load of paddy fields in various areas of rice-growing areas. The system includes a nitrogen removal amount calculation unit, a regional hierarchical unit, and a hierarchical management unit.

[0132] The nitrogen removal calculation unit is used to calculate the nitrogen removal amount using the following formula:

[0133] ;

[0134] ;

[0135] ;

[0136] In the above formula, Small wetlands nitrogen removal rate Small wetlands Nitrogen load in paddy field runoff, Small wetlands nitrogen removal rate Small wetlands The nitrogen removal rate constant, Small wetlands Hydraulic residence time, Small wetlands vegetation coverage Small wetlands The influent nitrogen concentration, Small wetlands Temperature;

[0137] The regional classification unit is used to determine the type of each region within the rice-growing area according to the following principles:

[0138] like ,and Then determine the area within the rice-growing region. It belongs to Category 1 key restoration area;

[0139] like ,and Then determine the area within the rice-growing region. It belongs to Category 2 optimization and efficiency enhancement area;

[0140] like ,and Then determine the area within the rice-growing region. It belongs to Class 3 routine monitoring area;

[0141] like ,and Then determine the area within the rice-growing region. It belongs to Class 4 ecological protection area;

[0142] In the above formula, Within the rice-growing area Nitrogen load in paddy field runoff, Within the rice-growing area The amount of nitrogen removed, i.e., the area The total nitrogen removal of all small and micro wetlands in the region. The number of regions to be divided within the rice-growing area;

[0143] The hierarchical control unit performs regional control based on the following strategies:

[0144] For Class 1 key restoration areas, a management strategy of appropriately increasing the area of ​​small and micro wetlands will be adopted;

[0145] For the Class 2 optimization and efficiency enhancement zone, a control strategy of increasing the vegetation coverage of small wetlands is adopted;

[0146] For Class 3 conventional monitoring areas, paddy field nitrogen load monitoring is adopted, and wetland restoration management strategies are implemented when nitrogen load increases.

[0147] For Class 4 ecological protection areas, a management strategy is adopted that prohibits the filling and encroachment of small wetlands and maintains the existing area of ​​small wetlands.

[0148] The specific management strategy of appropriately increasing the area of ​​small wetlands includes:

[0149] Determine whether the vegetation cover of the small wetlands in the key restoration area of ​​Category 1 is less than 0.5. If it is not less than 0.5, directly increase the area of ​​the small wetlands. If it is less than 0.5, first increase the vegetation cover of the small wetlands to 0.5, and calculate the nitrogen removal amount of the small wetlands after the increase in vegetation cover, and determine the nitrogen removal amount at this time. If the condition is met, the repair work will stop; if not, the area of ​​the small wetland will be increased.

[0150] The required increase in the area of ​​small wetlands is calculated using the following formula:

[0151] ;

[0152] ;

[0153] ;

[0154] ;

[0155] In the above formula, Key restoration area The area of ​​small wetlands that need to be increased Key restoration area The total area of ​​small wetlands will be increased. Key restoration area The existing area of ​​small wetlands, Key restoration area The hydraulic retention time of all small wetlands after increasing their area. Key restoration area Average flow rate of paddy field drainage, Key restoration area Depth of small wetlands Key restoration area The area of ​​rice paddies, Key restoration area Nitrogen removal rate of all small wetlands after increasing the area of ​​small wetlands. Key restoration area The nitrogen removal rate constant after increasing the vegetation cover of small wetlands to 0.5. The number of regions to be divided in the rice-growing area. Within the rice-growing area Nitrogen removal load of small wetlands Key restoration area Nitrogen load in paddy fields.

Claims

1. A method for assessing the nitrogen reduction potential of small wetlands in rice-growing areas, characterized in that, The method includes: Collect relevant data and calculate the nitrogen reduction potential assessment index for small wetlands in rice-growing areas, including nitrogen removal rate; The nitrogen removal rate is calculated using the following formula: ； ； In the above formula, Small wetlands nitrogen removal rate Small wetlands The nitrogen removal rate constant, Small wetlands Hydraulic residence time, Small wetlands vegetation coverage Small wetlands The influent nitrogen concentration, Small wetlands The temperature.

2. The method for assessing the nitrogen reduction potential of small wetlands in rice-growing areas according to claim 1, characterized in that, The nitrogen reduction potential assessment indicators also include nitrogen removal volume and the economic benefits of nitrogen removal; The nitrogen removal rate is calculated using the following formula: ； The economic benefits of nitrogen removal are calculated using the following formula: ； In the above formula, Small wetlands nitrogen removal rate Small wetlands Nitrogen load in paddy field runoff, Small wetlands nitrogen removal rate Small wetlands The economic benefits of nitrogen removal The nitrogen concentration in the influent of the wastewater treatment plant. This refers to the nitrogen concentration in the effluent from a wastewater treatment plant.

3. A method for hierarchical management and control of small wetlands in rice-growing areas, characterized in that, The method includes: Based on the nitrogen removal capacity of small wetlands in rice-growing areas, and combined with the nitrogen load of paddy fields in different regions within the rice-growing areas, small wetlands in different areas of the rice-growing areas are subject to graded management and control, including: like ,and Then determine the area within the rice-growing region. It belongs to Category 1 key restoration area, and the management strategy of appropriately increasing the area of ​​small and micro wetlands is adopted; like ,and Then determine the area within the rice-growing region. It belongs to the Class 2 optimization and efficiency enhancement area, and adopts the management strategy of increasing the vegetation coverage of small wetlands; like ,and Then determine the area within the rice-growing region. It belongs to Class 3 conventional monitoring area, and adopts the monitoring of nitrogen load in paddy fields. When the nitrogen load increases, the wetland restoration management strategy is implemented. like ,and Then determine the area within the rice-growing region. It belongs to Class 4 ecological protection area, and adopts the management strategy of prohibiting landfill and encroachment on small wetlands and maintaining the existing area of ​​small wetlands; In the above formula, Within the rice-growing area Nitrogen load in paddy field runoff, Within the rice-growing area The amount of nitrogen removed, i.e., the area The sum of nitrogen removal from all small and micro wetlands in the region. The number of regions to be divided within the rice-growing area; in, The calculation method includes: first calculating the nitrogen removal rate according to the method described in claim 1, and then calculating the nitrogen removal amount based on the nitrogen removal rate.

4. The method for hierarchical management and control of small wetlands in rice-growing areas according to claim 3, characterized in that, The specific management strategy of appropriately increasing the area of ​​small wetlands includes: Determine whether the vegetation cover of the small wetlands in the key restoration area of ​​Category 1 is less than 0.

5. If it is not less than 0.5, directly increase the area of ​​the small wetlands. If it is less than 0.5, first increase the vegetation cover of the small wetlands to 0.5, and calculate the nitrogen removal amount of the small wetlands after the increase in vegetation cover, and determine the nitrogen removal amount at this time. If the condition is met, the repair work will stop; if not, the area of ​​the small wetland will be increased.

5. A method for hierarchical management and control of small wetlands in rice-growing areas according to claim 4, characterized in that, The required increase in the area of ​​small wetlands is calculated using the following formula: ； ； ； ； In the above formula, Key restoration area The area of ​​small wetlands that need to be increased Key restoration area The total area of ​​small wetlands will be increased. Key restoration area The existing area of ​​small wetlands, Key restoration area The hydraulic retention time of all small wetlands after increasing their area. Key restoration area Average flow rate of paddy field drainage, Key restoration area Depth of small wetlands Key restoration area The area of ​​rice paddies, Key restoration area Nitrogen removal rate of all small wetlands after increasing the area of ​​small wetlands. Key restoration area The nitrogen removal rate constant after increasing the vegetation cover of small wetlands to 0.

5. The number of regions to be divided in the rice-growing area. Within the rice-growing area Nitrogen removal load of small wetlands Key restoration area Nitrogen load in paddy fields.

6. A system for assessing the nitrogen reduction potential of small wetlands in rice-growing areas, characterized in that, The system is used to collect relevant data and calculate the nitrogen reduction potential assessment index of small wetlands in rice-growing areas, including a nitrogen removal rate calculation unit. The nitrogen removal rate calculation unit is used to calculate the nitrogen removal rate using the following formula: ； ； In the above formula, Small wetlands nitrogen removal rate Small wetlands The nitrogen removal rate constant, Small wetlands Hydraulic residence time, Small wetlands vegetation coverage Small wetlands The influent nitrogen concentration, Small wetlands The temperature.

7. A nitrogen reduction potential assessment system for small wetlands in rice-growing areas according to claim 6, characterized in that, The system also includes a nitrogen removal calculation unit and a nitrogen removal economic benefit calculation unit; The nitrogen removal calculation unit is used to calculate the nitrogen removal amount using the following formula: ； The nitrogen removal economic benefit calculation unit is used to calculate the nitrogen removal economic benefit using the following formula: ； In the above formula, Small wetlands nitrogen removal rate Small wetlands Nitrogen load in paddy field runoff, Small wetlands nitrogen removal rate Small wetlands The economic benefits of nitrogen removal The nitrogen concentration in the influent of the wastewater treatment plant. This refers to the nitrogen concentration in the effluent from a wastewater treatment plant.

8. A hierarchical management and control system for small-scale wetlands in rice-growing areas, characterized in that, The system is used to classify and manage small wetlands in different areas of rice-growing regions based on the nitrogen removal capacity of small wetlands in rice-growing areas and the nitrogen load of paddy fields in different areas of rice-growing regions. It includes a nitrogen removal capacity calculation unit, a regional classification unit, and a classification and management unit. The nitrogen removal calculation unit is used to calculate the nitrogen removal amount using the following formula: ； ； ； In the above formula, Small wetlands nitrogen removal rate Small wetlands Nitrogen load in paddy field runoff, Small wetlands nitrogen removal rate Small wetlands The nitrogen removal rate constant, Small wetlands Hydraulic residence time, Small wetlands vegetation coverage Small wetlands The influent nitrogen concentration, Small wetlands Temperature; The regional classification unit is used to determine the type of each region within the rice-growing area according to the following principles: like ,and Then determine the area within the rice-growing region. It belongs to Category 1 key restoration area; like ,and Then determine the area within the rice-growing region. It belongs to Category 2 optimization and efficiency enhancement area; like ,and Then determine the area within the rice-growing region. It belongs to Class 3 routine monitoring area; like ,and Then determine the area within the rice-growing region. It belongs to Class 4 ecological protection area; In the above formula, Within the rice-growing area Nitrogen load in paddy field runoff, Within the rice-growing area The amount of nitrogen removed, i.e., the area The sum of nitrogen removal from all small and micro wetlands in the region. The number of regions to be divided within the rice-growing area; The hierarchical control unit performs regional control based on the following strategies: For Class 1 key restoration areas, a management strategy of appropriately increasing the area of ​​small and micro wetlands will be adopted; For the Class 2 optimization and efficiency enhancement zone, a control strategy of increasing the vegetation coverage of small wetlands is adopted; For Class 3 conventional monitoring areas, paddy field nitrogen load monitoring is adopted, and wetland restoration management strategies are implemented when nitrogen load increases. For Class 4 ecological protection areas, a management strategy is adopted that prohibits the filling and encroachment of small wetlands and maintains the existing area of ​​small wetlands.

9. A hierarchical management and control system for small wetlands in rice-growing areas according to claim 8, characterized in that, The specific management strategy of appropriately increasing the area of ​​small wetlands includes: Determine whether the vegetation cover of the small wetlands in the key restoration area of ​​Category 1 is less than 0.

5. If it is not less than 0.5, directly increase the area of ​​the small wetlands. If it is less than 0.5, first increase the vegetation cover of the small wetlands to 0.5, and calculate the nitrogen removal amount of the small wetlands after the increase in vegetation cover, and determine the nitrogen removal amount at this time. If the condition is met, the repair work will stop; if not, the area of ​​the small wetland will be increased.

10. A hierarchical management and control system for small-scale wetlands in rice-growing areas according to claim 9, characterized in that, The required increase in the area of ​​small wetlands is calculated using the following formula: ； ； ； ； In the above formula, Key restoration area The area of ​​small wetlands that need to be increased Key restoration area The total area of ​​small wetlands will be increased. Key restoration area The existing area of ​​small wetlands, Key restoration area The hydraulic retention time of all small wetlands after increasing their area. Key restoration area Average flow rate of paddy field drainage, Key restoration area Depth of small wetlands Key restoration area The area of ​​rice paddies, Key restoration area Nitrogen removal rate of all small wetlands after increasing the area of ​​small wetlands. Key restoration area The nitrogen removal rate constant after increasing the vegetation cover of small wetlands to 0.

5. The number of regions to be divided in the rice-growing area. Within the rice-growing area Nitrogen removal load of small wetlands Key restoration area Nitrogen load in paddy fields.

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