Drainage basin space planting industry pollution emission intensity calculation method based on land utilization type

Abstract

The invention discloses a land utilization type-based drainage basin space planting industry pollution emission intensity calculation method, and relates to the technical field of pollution emission intensity calculation, and the method comprises the steps: firstly carrying out the drainage basin division of a research region through ArcSWAT, and carrying out the interpretation of recent remote sensing image data through ENVI, and obtaining the land utilization type of the region; secondly, extracting a land utilization type of the research region through extraction according to a mask in an ArcGIS, and obtaining the number of grids of each land utilization in the administrative region and each small watershed through a histogram in the GIS; then, according to the statistical yearbook of the research area, obtaining the chemical fertilizer usage amount and the cultivated land area proportion, and calculating to obtain the planting industry pollutant discharge amount of each administrative area; and finally, based on the pollutant discharge amount of the planting industry of each administrative region and the cultivated land grid number of each administrative region, converting to obtain the pollution discharge intensity of the spatial cultivated land grid of each administrative region, calculating the pollution discharge intensity of the spatial cultivated land grid of each small watershed contained in each administrative region, and finally obtaining a total pollution discharge intensity value.

Description

Technical Field

[0001] The present invention relates to the technical field of pollution emission intensity calculation, and in particular to a method for calculating pollution emission intensity of crop production in a watershed space based on land use types. Background Art

[0002] Natural factors (such as soil, topography, landforms and rainfall) have an important impact on the emissions of various pollution sources, and there is also a significant connection between human activities and pollution source emissions. Land use types can comprehensively reflect human activities, and the uneven spatial distribution of different land use types will affect the spatial distribution of pollution sources. When calculating the intensity of pollution sources, it is necessary to consider the spatial differences in land use types, and use GIS (geographic information system) and other technologies to combine land use data with pollution source data to more accurately analyze the distribution of pollution sources and the scope of influence. At present, when calculating the intensity of pollution sources based on land use types, cultivated land grids are generally used to calculate the intensity of agricultural pollution sources. At the same time, the use of pesticides and fertilizers in agricultural pollution sources will bring non-point source pollution. Nutrients such as nitrogen and phosphorus in pesticides and fertilizers, as well as organic pollutants in pesticides, may enter water bodies and soil with rainfall, irrigation, etc., causing eutrophication of water bodies and soil pollution. Factors such as farmland area and the amount of pesticides and fertilizers applied should be considered in the calculation. However, the existing technology has the following disadvantages: First, to accurately calculate pollution sources based on land use types, high-precision land use data and detailed pollution source data are required, including the breakdown of land use types, pollutant emission coefficients of different industries, etc. The cost of data acquisition is high, and in some areas, there may be missing or inaccurate data, which affects the reliability of the calculation results.

[0003] Secondly, although the main factors of land use type are taken into consideration, there may still be some unforeseen factors that affect the generation and emission of pollution sources in practice, such as sudden environmental events, new pollutants brought about by the application of new technologies, etc. These factors may not be fully reflected in the calculation of pollution sources based on land use type, resulting in certain uncertainties in the calculation results.

[0004] In summary, a method for calculating the pollution emission intensity of agricultural production in watershed space based on land use type is urgently needed to overcome the problems existing in the existing technology. Summary of the invention

[0005] The purpose of the present invention is to provide a method for calculating the pollution emission intensity of crop industry in watershed space based on land use type. Based on the grid number of each land use type in each county and city, the pollution source emission amount of each small watershed in the study area is determined, and combined with the grid number of cultivated land in each small watershed, the emission intensity of crop industry in each small watershed space can be calculated.

[0006] To achieve the above object, the present invention provides a method for calculating the pollution emission intensity of crop production in a watershed space based on land use types, comprising the following steps: Step 1: First, use ArcSWAT (soil and water assessment model) to divide the study area into watersheds, and use ENVI (remote sensing image processing platform) to interpret the remote sensing image data in recent years to obtain the land use type of the region; Step 2: Extract the land use types in the study area by mask extraction in ArcGIS (geographic information system software), and obtain the number of grids of each type of land use in the administrative area and each small watershed through the histogram in GIS; Step 3: Obtain fertilizer usage and cultivated land area ratio according to the statistical yearbook of the study area, and calculate the pollutant emissions from crop production in each administrative area; Step 4: Based on the pollutant emissions from the planting industry in a certain administrative region and the number of cultivated land grids in a certain administrative area, the pollution emission intensity of the spatial cultivated land grid of a certain administrative region is converted, and the pollution emission intensity of the spatial cultivated land grid of each small watershed contained in the administrative region is calculated to finally obtain the total pollution emission intensity value.

[0007] Preferably, the land use types include cultivated land, forest land, shrubs, wasteland, water bodies, public utility land and settlements.

[0008] Preferably, the calculation expression of the pollutant emissions from planting industry in step 3 is as follows: ; In the formula, It indicates the pollutant emission from planting industry in a certain area, in tons / year; It represents the total sown area of ​​crops in a province, in hectares; It indicates the pollutant coefficient of crop planting in a certain area, in kg / hectare; It indicates the area of ​​a certain province's garden in hectares; It indicates the pollutant coefficient of a certain area of ​​garden land, in kg / hectare; It indicates the usage of nitrogen-containing fertilizer or phosphorus-containing fertilizer per unit area for crop production in a certain region during the survey year, in kg / hectare; It indicates the usage of nitrogen-containing fertilizers or phosphorus-containing fertilizers used for crop industry in a certain region during the second pollution census year, in kg / hectare. The usage of nitrogen-containing fertilizers refers to the pure usage of nitrogen fertilizers and nitrogen-containing compound fertilizers; the usage of phosphorus-containing fertilizers refers to the pure usage of phosphorus fertilizers and phosphorus-containing compound fertilizers.

[0009] Preferably, the expression for the pollution emission intensity of the spatial cultivated land grid of a certain administrative region is obtained by converting the pollutant emission of the planting industry in a certain administrative region and the number of cultivated land grids in a certain administrative region as follows: ; In the formula, It represents the pollution emission intensity of a unit grid in a certain administrative area; It indicates the pollutant emission of planting industry in a certain administrative area, in tons / year; Indicates the number of spatial cultivated land grids in a certain administrative area.

[0010] Preferably, the calculation expression of the pollution emission intensity of the spatial cultivated land grid of each small watershed contained in a certain administrative area is as follows: ; In the formula, Indicates the number of spatial cultivated land grids in a small watershed partition, Represents the pollution emission intensity of the spatial cultivated land raster of a small watershed partition.

[0011] Preferably, the expression of the total pollution emission intensity value is as follows: ; In the formula, It represents the total intensity of pollution emissions from the planting industry in the total space of a small watershed.

[0012] Therefore, the present invention adopts the above-mentioned method for calculating the pollution emission intensity of crop production in watershed space based on land use type, which has the following beneficial effects: (1) The present invention combines land use type data with pollution source data, changing the previous method of calculating from the perspective of pollution sources alone. It introduces land use as an important environmental factor, realizes multi-dimensional analysis, and can more comprehensively understand the generation and distribution mechanism of pollution sources. (2) The present invention uses technologies such as geographic information system (GIS) to accurately determine the spatial distribution of pollution sources in different land use types and intuitively display the distribution characteristics of pollution sources in the region, which helps to carry out more targeted environmental monitoring and management and provide more accurate spatial information for environmental planning and decision-making.

[0013] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an overall flow chart of the method for calculating the pollution emission intensity of crop production in watershed space based on land use type of the present invention; Figure 2 A schematic diagram of numbering administrative regions and small watersheds in an embodiment of the present invention; Figure 3 This is a schematic diagram of the numbering of emission intensities of different pollution sources according to an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] See also Figure 1-Figure 3 The calculation method of pollution emission intensity of crop industry in watershed space based on land use type includes the following steps: Step 1: First, use ArcSWAT to divide the watershed of the study area, and use ENVI to interpret the remote sensing image data of recent years to obtain the land use type of the area; among them, the land use type includes cultivated land, forest land, shrubs, wasteland, water bodies, public utility land and residential areas; Step 2: Extract the land use types of the study area by mask extraction in ArcGIS, and obtain the number of grids of each type of land use in the administrative area and each small watershed through the histogram in GIS; Step 3: According to the statistical yearbook of the study area, the fertilizer usage and the proportion of cultivated land area are obtained, and the pollutant emissions from the planting industry in each administrative area are calculated; the calculation expression for the pollutant emissions from the planting industry is as follows: ; In the formula, It indicates the pollutant emission from planting industry in a certain area, in tons / year; It represents the total sown area of ​​crops in a province, in hectares; It indicates the pollutant coefficient of crop planting in a certain area, in kg / hectare; It indicates the area of ​​a certain province's garden in hectares; It indicates the pollutant coefficient of a certain area of ​​garden land, in kg / hectare; It indicates the usage of nitrogen-containing fertilizer or phosphorus-containing fertilizer per unit area for crop production in a certain region during the survey year, in kg / hectare; It indicates the usage of nitrogen-containing fertilizers or phosphorus-containing fertilizers used for crop industry in a certain region during the second pollution census year, in kg / hectare. The usage of nitrogen-containing fertilizers refers to the pure usage of nitrogen fertilizers and nitrogen-containing compound fertilizers; the usage of phosphorus-containing fertilizers refers to the pure usage of phosphorus fertilizers and phosphorus-containing compound fertilizers.

[0017] Step 4: Based on the pollutant emissions from the planting industry in a certain administrative area and the number of cultivated land grids in a certain administrative area, the pollution emission intensity of the spatial cultivated land grid of a certain administrative area is converted, and the pollution emission intensity of the spatial cultivated land grid of each small watershed contained in a certain administrative area is calculated, and finally the total pollution emission intensity value is obtained; the details are as follows: The expression of the pollution emission intensity of the spatial cultivated land grid of a certain administrative region is obtained based on the pollutant emissions of the planting industry in a certain administrative region and the number of cultivated land grids in a certain administrative region as follows: ; In the formula, It represents the pollution emission intensity of a unit grid in a certain administrative area; It indicates the pollutant emission of planting industry in a certain administrative area, in tons / year; Indicates the number of spatial cultivated land grids in a certain administrative area.

[0018] The calculation expression of the pollution emission intensity of the spatial cultivated land grid of each small watershed in a certain administrative area is as follows: ; In the formula, Indicates the number of spatial cultivated land grids in a small watershed partition, Represents the pollution emission intensity of the spatial cultivated land raster of a small watershed partition.

[0019] The expression of the total pollution emission intensity value is as follows: ; In the formula, It represents the total intensity of pollution emissions from the planting industry in the total space of a small watershed.

[0020] Example Taking a certain area as an example, the present invention applies a method for calculating the pollution emission intensity of crop industry in watershed space based on land use type as follows: obtain the remote sensing image data of a certain area in recent years, obtain the land use type of the area in recent years by interpretation, extract the land use type of the study area by mask in ArcGIS, and divide the rivers in the study area into watersheds by ArcSWAT. The codes of each administrative area are a, b, ..., and each small watershed is coded as 001, 002, ..., xyz, such as Figure 2 As shown in the figure, the small watershed 008 contains parts of the three counties a, b, and d. The different counties in each small watershed are numbered a-008, b-008, and d-008, as shown in the figure. Figure 3As shown in the figure, the number of cultivated land type grids in counties and cities in regions a, b, and d are calculated to be 125599, 412961, 1735, and 008, respectively. The number of grids of cultivated land types in small watersheds in each county and city is 5364. The pollutant emission of planting industry in each county and city is divided by the number of cultivated land type grids in each county and city to obtain the pollutant emission intensity of planting industry. For example, the ammonia nitrogen emission of planting industry in regions a, b, and d is 8.696 t / a, 35.935 t / a, and 0.426 t / a, respectively. The number of cultivated land type grids in regions a, b, and d is 125599, 412961, and 1735, respectively. The ammonia nitrogen emission intensity of unit grid pollutants in regions a, b, and d is calculated to be 0.00007 t / a, 0.00009 t / a, and 0.00025 t / a, respectively. The number of grids of cultivated land types in each small watershed in each county and city is multiplied by the corresponding pollutant emission intensity. For example, the number of grids of cultivated land types in area d in the 008 watershed is 280, and the ammonia nitrogen emission intensity of the planting industry in area d in the 008 watershed is 0.07t / a. Then the pollutant emission intensity of each watershed is added together to obtain the pollution source emission intensity of each small watershed. For example: the pollution source emission intensity of small watershed 008 is 0.15 t / a when a-008, b-008, and d-008 are added together.

[0021] In addition, taking a certain area in 2022 as an example, the present invention obtains remote sensing image data of a certain area in 2022, obtains the land use type of the area in 2022 through interpretation, extracts the land use type of the study area according to the mask in ArcGIS, and calculates the number of rasters of cultivated land type in each county and city in the region and the number of rasters of cultivated land type in each small watershed in each county and city.

[0022] Based on the crop pollutant emissions provided by the Second Pollution Census, and integrated with relevant data such as local fertilizer usage and proportion of cultivated land area in 2017 and 2022, the crop pollutant emissions in the Second Pollution Census (2017) were converted to obtain the crop pollutant emissions in each administrative region in 2022. The pollution intensity of the spatial cultivated land grids in each administrative region was obtained based on the number of cultivated land grids in each administrative region, and the pollution intensity of the spatial cultivated land grids of each small watershed contained in each administrative region was calculated. Finally, the pollution intensity of the spatial cultivated land grids of each small watershed and the total pollution intensity value were summarized.

[0023] Therefore, the present invention adopts the above-mentioned method for calculating the pollution emission intensity of spatial agricultural industry in the watershed based on land use type, and determines the pollution source emission of each small watershed in the study area based on the grid number of each land use type in each county and city, and combines the grid number of cultivated land in each small watershed to realize the calculation of the emission intensity of spatial agricultural pollution sources in each small watershed, which provides a new method for environmental monitoring and planning decision-making.

[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. The calculation method of pollution emission intensity of crop production in watershed space based on land use type is characterized by: The following steps are involved: Step 1: First, use ArcSWAT to divide the watershed of the study area, and use ENVI to interpret the remote sensing image data in recent years to obtain the land use type of the region; Step 2: Extract the land use types of the study area by mask extraction in ArcGIS, and obtain the number of grids of each type of land use in the administrative area and each small watershed through the histogram in GIS; Step 3: Obtain fertilizer usage and cultivated land area ratio according to the statistical yearbook of the study area, and calculate the pollutant emissions from crop production in each administrative area; Step 4: Based on the pollutant emissions from the planting industry in a certain administrative region and the number of cultivated land grids in a certain administrative area, the pollution emission intensity of the spatial cultivated land grid of a certain administrative region is converted, and the pollution emission intensity of the spatial cultivated land grid of each small watershed contained in the administrative region is calculated to finally obtain the total pollution emission intensity value.

2. The method for calculating the pollution emission intensity of crop production in watershed space based on land use type according to claim 1 is characterized by: Land use types include cultivated land, forest land, shrubs, wasteland, water bodies, utility land and settlements.

3. The method for calculating the pollution emission intensity of crop production in watershed space based on land use type according to claim 2 is characterized in that: The calculation expression of the pollutant emissions from planting industry in step 3 is as follows: ； In the formula, It indicates the pollutant emission from planting industry in a certain area, in tons / year; It represents the total sown area of ​​crops in a province, in hectares; It indicates the pollutant coefficient of crop planting in a certain area, in kg / hectare; It indicates the area of ​​a certain province's garden in hectares; It indicates the pollutant coefficient of a certain area of ​​garden land, in kg / hectare; It indicates the usage of nitrogen-containing fertilizer or phosphorus-containing fertilizer per unit area for crop production in a certain region during the survey year, in kg / hectare; It indicates the usage per unit area of ​​nitrogen-containing fertilizers or phosphorus-containing fertilizers used for crop production in a certain region during the second pollution census survey, in kilograms per hectare.

4. The method for calculating the pollution emission intensity of crop production in watershed space based on land use type according to claim 3 is characterized in that: The expression of the pollution emission intensity of the spatial cultivated land grid of a certain administrative region is obtained based on the pollutant emissions of the planting industry in a certain administrative region and the number of cultivated land grids in a certain administrative region as follows: ； In the formula, It represents the pollution emission intensity of a unit grid in a certain administrative area; It indicates the pollutant emission of planting industry in a certain administrative area, in tons / year; Indicates the number of spatial cultivated land grids in a certain administrative area.

5. The method for calculating the pollution emission intensity of crop production in watershed space based on land use type according to claim 4 is characterized in that: The calculation expression of the pollution emission intensity of the spatial cultivated land grid of each small watershed in a certain administrative area is as follows: ； In the formula, Indicates the number of spatial cultivated land grids in a small watershed partition, Represents the pollution emission intensity of the spatial cultivated land raster of a small watershed partition.

6. The method for calculating the pollution emission intensity of crop production in watershed space based on land use type according to claim 5 is characterized in that: The expression of the total pollution emission intensity value is as follows: ； In the formula, It represents the total intensity of pollution emissions from the planting industry in the total space of a small watershed.

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