Method for calculating farmland non-point source pollutant river entering amount, electronic equipment and medium

Abstract

The invention provides a calculation method of farmland non-point source pollutant river entering quantity, electronic equipment and a medium, the day-by-day river entering quantity of farmland non-point source pollutants under different conditions can be obtained by combining rainfall, crop fertilization period, non-fertilization period and other conditions, the change condition of the farmland non-point source pollutant river entering quantity in the whole production cycle process can be reflected, and the calculation accuracy is improved. The accuracy of farmland non-point source pollutant river entering amount calculation is improved, and a reliable data source is provided for later treatment measure arrangement.

Description

Technical Field

[0001] The invention belongs to the technical field of water resource application and water environment, and in particular relates to a method for calculating the amount of farmland non-point source pollutants entering a river, electronic equipment and a medium. Background Art

[0002] Farmland non-point source pollution refers to the pollution of water bodies caused by the frequent use of large amounts of fertilizers, etc., in the process of agricultural planting and production to ensure the production and harvest of crops. These substances accumulate in the soil, and driven by rainfall and irrigation, the nitrogen and phosphorus in the fertilizers migrate to water bodies through runoff, leaching, and lateral infiltration, or enter the atmosphere through volatilization, and then migrate to water bodies through atmospheric dry and wet deposition. The traditional method for calculating the loss of farmland non-point source pollution is that the amount of pollutant loss during the entire monitoring period (a complete year) is equal to the sum of the product of the pollutant concentration in each runoff water and the volume of runoff water (or leached water). The amount of pollutants entering the river is usually calculated using the river entry coefficient method, which is obtained by multiplying the pollutant loss by the river entry coefficient.

[0003] The amount of farmland drainage and the concentration of pollutants in water are important factors that determine the amount of farmland non-point source pollutants. However, there are significant temporal and spatial differences in farmland drainage. The main factors affecting farmland drainage include rainfall, rainfall intensity, soil properties, crop planting and growth, and the main factors affecting the concentration of pollutants in farmland drainage include drainage, accumulated pollutant concentration and form in the soil, etc. For example, the greater the rainfall intensity and the greater the runoff, the more pollution will migrate from farmland to water bodies; the higher the amount of fertilizer, the greater the risk of pollution. The first week of fertilization is a high-risk period for farmland non-point source pollution, and the risk is lower after one week of fertilization. At present, the calculation method of farmland non-point source pollution generally calculates large-scale and long-term scales such as annual farmland non-point source pollutant emissions and river discharge, without considering the influence of rainfall and fertilization factors. The calculation of farmland non-point source pollution entering the river is not accurate enough, which restricts the setting of targeted governance measures. Summary of the invention

[0004] The purpose of the present invention is to provide a method, electronic equipment and medium for calculating the amount of farmland non-point source pollution entering a river in view of the deficiencies in the prior art, so as to improve the accuracy of calculating the amount of farmland non-point source pollution entering a river.

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

[0006] A method for calculating the amount of farmland non-point source pollutants entering a river is provided. According to the crop fertilization pattern and rainfall conditions, the daily amount of farmland non-point source pollutants entering a river W is calculated. The expression of W is as follows:

[0007] W=C 0 ×λ×Q 1 +C 2 ×λ×Q 1

[0008] C 2 =(P 1 +P 2 ) / (Q 3 ′×1000)

[0009] Among them, C 0 is the pollutant emission concentration during the non-fertilization period, C 2 is the pollutant emission concentration of the first rainfall after fertilization, λ is the coefficient of non-point source pollutants from farmland entering the river, Q 1 is the daily drainage volume of farmland, Q 3 ′ is the rainfall runoff of the first rainfall during the fertilization period, P 1 is the loss of non-point source pollutants from farmland during the fertilization period, P 2 The amount of non-point source pollutants lost from farmland that divert water for irrigation.

[0010] The present invention combines conditions such as rainfall, crop fertilization period and non-fertilization period to obtain the daily amount of farmland non-point source pollutants entering the river under different conditions, which can reflect the changes in the amount of farmland non-point source pollutants entering the river during the entire production cycle, improves the accuracy of calculation of the amount of farmland non-point source pollutants entering the river, and provides a reliable data source for the arrangement of subsequent control measures.

[0011] Furthermore, the amount of non-point source pollutants lost from farmland during the fertilization period is P 1 Calculated by the following formula:

[0012] P 1 =∑M i T ij ζ i

[0013] Among them, M i is the planting area of ​​the i-th crop, T ij is the average per-mu fertilizer application amount of the i-th crop in the j-th fertilization, ζ i is the pollutant loss coefficient of the i-th crop.

[0014] Furthermore, the amount of non-point source pollutants lost from irrigation water is P 2 Calculated by the following formula:

[0015] P 2 =ζ i T 2

[0016] T 2 =C 1 ∑Q 2i / 1000

[0017] Among them, C 1 Pollutant concentration in water diverted for irrigation, Q2i is the annual irrigation water diversion of the i-th crop, ζ i is the pollutant loss coefficient of the i-th crop.

[0018] Furthermore, the farmland non-point source pollutants include at least two of the following: total phosphorus, total nitrogen, ammonia nitrogen, and chemical oxygen demand.

[0019] Based on the same inventive concept, the present invention also provides an electronic device, including:

[0020] one or more processors;

[0021] A memory having one or more programs stored thereon, which, when executed by the one or more processors, enables the one or more processors to implement the steps of a method for calculating the amount of farmland non-point source pollutants entering a river.

[0022] Based on the same inventive concept, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a method for calculating the amount of farmland non-point source pollutants entering a river.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention combines conditions such as rainfall, crop fertilization period and non-fertilization period to obtain the daily amount of farmland non-point source pollutants entering the river under different conditions, which can reflect the changes in the amount of farmland non-point source pollutants entering the river during the entire production cycle, improves the accuracy of calculation of the amount of farmland non-point source pollutants entering the river, and provides a reliable data source for the arrangement of subsequent control measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A flow chart of a method for calculating the amount of farmland non-point source pollutants entering a river according to the present invention;

[0026] Figure 2 This is a curve showing the daily change in the amount of TP from farmland nonpoint sources entering the river in a typical year. DETAILED DESCRIPTION

[0027] The present invention will be described in detail below in conjunction with the embodiments. It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear in the following, they only indicate that the upper, lower, left and right directions are consistent with the drawings themselves, and do not limit the structure.

[0028] Example 1

[0029] like Figure 1 , a method for calculating the amount of farmland non-point source pollutants entering a river in this embodiment includes the following steps:

[0030] Obtain farmland planting structure, including crop types and crop planting areas; obtain fertilization patterns for various crops, including fertilization time periods and fertilization amounts.

[0031] Calculate the amount of non-point source pollutants lost from farmland during the fertilization period P 1 , unit t, P 1 The expression is as follows:

[0032] P 1 =∑M i T ij ζ i

[0033] Among them, M i is the planting area of ​​the i-th crop, in mu; T ij is the average per mu fertilizer amount of the i-th crop in the j-th fertilization, in units of t / mu·time; i is the pollutant loss coefficient of the i-th crop.

[0034] The pure fertilizer amount refers to the amount of nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer converted according to the percentage of nitrogen, phosphorus pentoxide, and potassium oxide respectively, and the amount of compound fertilizer converted according to its main components. The pure fertilizer amount = the actual amount of fertilizer applied × the percentage of the effective ingredient content of a certain fertilizer. The calculation of the pure fertilizer amount is an existing technology.

[0035] The pollutant loss coefficients of different crops were obtained from the National Handbook of Farmland Non-point Source Pollution Emission Coefficients.

[0036] Calculate the amount of non-point source pollutants lost from irrigation water in farmland P 2 , unit t, P 2 The expression is as follows:

[0037] P 2 =ζ i T 2

[0038] T 2 =C 1 ΣQ 2i / 1000

[0039] Among them, C 1 The pollutant concentration of irrigation water, in kg / m 3 ;Q 2i is the annual irrigation water diversion of the i-th crop, unit: m 3 .

[0040] C 1It is obtained through water quality testing; by collecting farmland irrigation water diversion operation data, the daily irrigation water diversion volume of a certain crop in a typical year is obtained, and the daily irrigation water diversion volume of the crop in a year is added up to obtain the annual irrigation water diversion volume of the crop.

[0041] Calculate the pollutant emission concentration C of the first rainfall after fertilization 2 , unit: kg / m 3 , C 2 The expression is as follows:

[0042] C 2 =(P 1 +P 2 ) / (Q 3 ′×1000)

[0043] Among them, Q 3 ′ is the rainfall runoff of the first rainfall during the fertilization period, unit: m 3 .

[0044] Calculate the average concentration of non-point source pollutants entering the river during the non-fertilization period and the average river concentration during the fertilization period and The expression is as follows:

[0045]

[0046] Among them, λ is the coefficient of non-point source pollutants from farmland entering the river, C 0 It is the pollutant emission concentration during the non-fertilization period, that is, the pollutant emission concentration during the background period, in kg / m 3 ;

[0047] C 0 Obtained through water quality testing; the river inflow coefficient refers to the ratio of pollutant inflow to total pollutant discharge, usually between 0-1. The river inflow coefficient is determined empirically or calculated by the following formula: river inflow coefficient = river inflow / discharge, river inflow = measured pollutant concentration at the river mouth × daily discharge of farmland Q 1 , Emission = measured pollutant concentration at the farmland entrance × daily rainfall runoff Q 3 .

[0048] Refer to the "Hydrological Calculation Specifications for Water Conservancy and Hydropower Projects" (SL278-2020) and "Hydraulic Calculation Specifications for Water Conservancy Projects" (SL104-2015), and calculate the daily rainfall runoff Q based on basic data such as rainfall data, underlying surface composition, and catchment area. 3 and the rainfall runoff Q of the first rainfall during the fertilization period 3 ', which is the prior art.

[0049] Q 1 =Q 2+Q 3 -Q 4 -Q 5 , Q 2 is the daily irrigation water diversion of all crops in the farmland, which is obtained by adding up the daily irrigation water diversion of all crops, m 3 ;Q 4 is the daily evaporation of water area, m 3 ;Q 5 is the daily water consumption of all crops, m 3 .Q 5 From the data of the local irrigation experiment station, Q 4 Obtained from data from weather stations.

[0050] Calculate the daily amount of pollutants from farmland non-point sources entering the river, W, in kg. The expression of W is as follows:

[0051] W=W 0 +W 2

[0052]

[0053] That is, W = C 0 ×λ×Q 1 +C 2 ×λ×Q 1

[0054] Example 2

[0055] In a water environment management project, according to the pollution source investigation and pollution load calculation, farmland non-point source pollution is the main source of pollution factors entering the river. Its basin topography is a typical plain polder area with a total basin area of ​​135.42km 2 , of which 135,500 mu is cultivated land, accounting for 66.7%. The following is an example of the application of this embodiment. In addition, general water environment projects will focus on multiple pollutant water quality indicators, at least the following two: total phosphorus TP, total nitrogen TN, ammonia nitrogen NH 3 -N, chemical oxygen demand COD Cr However, the calibration methods of various water quality indicators are the same, and here we take the TP water quality indicator as an example.

[0056] (1) Through on-site investigation, discussion visits, and land space data collection, the main planting structure of the basin is "rice-wheat rotation", with double-season rice, grapes, and vegetables. The current planting structure of the basin is shown in Table 1.

[0057] Table 1 Current planting structure in the basin

[0058] Planting structure Double rice One Rice One Wheat Rice Shrimp single cropping of rice Grape Other vegetables total Cultivated land area (mu) 12863 62432 16143 11229 4068 28791 135526

[0059] (2) According to on-site investigation and relevant statistical data, the main farming system in the project basin is "one rice and one wheat", and the average annual fertilizer application is 30-70 kg / mu. This on-site investigation is based on the fertilizer application during the rice growth period. The pure fertilizer application amount is N40.24 kg / mu, P 2 O 5 24kg / mu, K 2 O24kg / mu, a total of 88.24kg / mu, the planting period of mid-late rice is from May to October, and the fertilization period is mainly distributed from May to August. Among them, the amount of basal fertilizer (basal fertilizer) applied from May to June accounts for 50% of the total fertilization in the growing season (compound fertilizer, urea), fertilization (tillering fertilizer) in July accounts for 25% (urea), fertilization (ear fertilizer) in early August accounts for 15% (compound fertilizer), and fertilization (granular fertilizer) in late August accounts for 10% (compound fertilizer). The calculation of the pure amount of fertilizer elements N and P per mu for double-season rice, one rice and one wheat, single-season rice, vegetables, etc. is shown in Table 2.

[0060] (3) Typical weirs in the project area were selected and 10 water quality monitoring points were set up at the entrances of farmland. Through sampling and collection, the average discharge concentration of TP during the background period (non-fertilization period) was determined to be 0.28 mg / L.

[0061] (4) Refer to the National Handbook of Farmland Non-point Source Pollution Emission Coefficients to determine the TP loss coefficients of different crops during the fertilization period as shown in Table 3.

[0062] (5) Based on the annual calculation scale, the TP loss during the fertilization period caused by non-point source fertilization of dike farmland is calculated as shown in Table 4.

[0063] Table 2 Statistics of current fertilization in the basin

[0064]

[0065] Table 3 Loss coefficients of different crops during fertilization period

[0066]

[0067]

[0068] Table 4. Table of loss during fertilization period caused by non-point source fertilization in embankment farmland

[0069]

[0070] (6) Considering that nitrogen and phosphorus pollutants in irrigation water in the polder area enter the river channel through pumping in the form of farmland runoff, the water intake of the downstream polder area during the irrigation period mainly comes from reciprocating flow backflow. Pollutants such as nitrogen and phosphorus in the irrigation water are backflowed into the main river channel from the reciprocating flow, increasing the non-point source pollution load of farmland in the basin. The multi-year average results of water quality monitoring TP in the downstream section of the main river channel during the irrigation period are shown in Table 5.

[0071] Table 5 Water quality monitoring results of the downstream section of the main river during the irrigation period

[0072] index Concentration (mg / L) Class III water quality standard (mg / L) TP 0.282 0.2

[0073] Calculate the loss of TP water diverted from outside for irrigation, as shown in Table 6.

[0074] Table 6 Loss of irrigation water TP

[0075] Pollution Factor Loss (t / a) TP 7.33

[0076] (7) Ten water quality monitoring points were set up at the river mouths (inland rivers, external rivers, etc.) of the dikes. The TP inflow coefficient of the dike farmland non-point source was determined by sampling and collection, as shown in Table 7.

[0077] Table 7 River Entry Coefficient Table

[0078] Pollution Factor River entry coefficient TP 0.52

[0079] (8) Calculate the emission concentration of the first rainfall after fertilization. Under the 50% frequency (typical year 2011), the emission of the first rainfall after basal fertilizer and topdressing is 336,800 m 3 、113,300m 3 The total annual discharge volume is 41.6927 million m 3 , and the average emission concentration of the first rainfall after fertilization was 1.39 mg / L.

[0080] (9) Calculate the daily inflow of TP from the farmland into the river and its changing curve (e.g. Figure 2 ).

[0081] Example 3

[0082] This embodiment provides an electronic device, including:

[0083] one or more processors;

[0084] A memory having one or more programs stored thereon, which, when executed by one or more processors, enables the one or more processors to implement the steps of a method for calculating the amount of farmland non-point source pollutants entering a river.

[0085] In some implementations, the memory may be a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory.

[0086] In some other implementations, the processor may be a central processing unit (CPU), a digital signal processor (DSP), or other general-purpose processors of various types, which are not limited herein.

[0087] This embodiment provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a method for calculating the amount of farmland non-point source pollutants entering a river.

[0088] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

Claims

1. A method for calculating the amount of farmland non-point source pollutants entering a river, characterized in that: The expression of the daily amount of pollutants from farmland into the river W is as follows: W=C0×λ×Q1+C2×λ×Q1 C2=(P1+P2) / (Q3′×1000) Among them, C0 is the pollutant emission concentration in the non-fertilization period, C2 is the pollutant emission concentration of the first rainfall after fertilization, λ is the coefficient of non-point source pollutants entering the river from farmland, Q1 is the daily drainage volume of farmland, Q3′ is the rainfall runoff of the first rainfall during the fertilization period, P1 is the loss of non-point source pollutants from farmland during the fertilization period, and P2 is the loss of non-point source pollutants from farmland by irrigation water.

2. The method for calculating the amount of farmland non-point source pollutants entering the river according to claim 1 is characterized in that: The loss of non-point source pollutants from farmland during the fertilization period, P1, is calculated by the following formula: P1=∑M i T ij g i Among them, M i is the planting area of ​​the i-th crop, T ij is the average per-mu fertilizer application amount of the i-th crop in the j-th fertilization, ζ i is the pollutant loss coefficient of the i-th crop.

3. The method for calculating the amount of farmland non-point source pollutants entering the river according to claim 1 is characterized in that: The loss of non-point source pollutants from irrigation water, P2, is calculated by the following formula: P2=ζ i T2 T2=C1∑Q 2i / 1000 Among them, C1 is the pollutant concentration of irrigation water, Q 2i is the annual irrigation water diversion of the i-th crop, ζ i is the pollutant loss coefficient of the i-th crop.

4. The method for calculating the amount of farmland non-point source pollutants entering a river according to claim 1, characterized in that: The farmland non-point source pollutants include at least two of the following: total phosphorus, total nitrogen, ammonia nitrogen, and chemical oxygen demand.

5. An electronic device, characterized in that: include: one or more processors; A memory having one or more programs stored thereon, which, when the one or more programs are executed by the one or more processors, enables the one or more processors to implement the steps of the method according to any one of claims 1 to 4.

6. A computer-readable storage medium, characterized in that: The computer program is stored therein, and when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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