Method for determining soil pollution status caused by livestock and poultry breeding sewage

Abstract

The method for determining the soil pollution condition caused by livestock and poultry breeding pollution provided by the embodiments of the present disclosure comprises: determining a livestock and poultry breeding area and a pollution monitoring area in a target monitoring area; dividing the pollution monitoring area into a key monitoring area and a non-key monitoring area based on the position of the livestock and poultry breeding area in the pollution monitoring area and the geographical features of the pollution monitoring area; determining sampling points in the key monitoring area according to a first sampling point arrangement mode, determining sampling points in the non-key monitoring area according to a second sampling point arrangement mode, and sampling according to the sampling points to obtain soil samples; detecting the soil samples for pollutants to obtain pollutant data of each sampling point, and inferring the soil pollution condition of the pollution monitoring area caused by the livestock and poultry breeding area based on the pollutant data. The sampling scheme provided by the embodiments of the present disclosure has guiding value for livestock and poultry breeding, and the determined soil pollution condition can reflect the influence of the distribution characteristics caused by geographical features.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of pollution monitoring, and particularly relates to a method for determining soil pollution caused by livestock and poultry breeding. BACKGROUND

[0002] At present, the proportion of the livestock and poultry breeding industry in the agricultural (agriculture, forestry, animal husbandry and fishery) output value has exceeded one fourth.

[0003] The livestock and poultry breeding area is generally located in rural areas far from cities, and various pollution emissions generated thereby may leak into the surrounding agricultural and forestry land and spread under the action of agricultural irrigation, farmland surface runoff and groundwater seepage, causing pollution of the surrounding agricultural land and groundwater. In order to understand the pollution status of the agricultural and forestry land caused by livestock and poultry breeding from a global perspective, the relevant authorities propose the requirement of soil environment monitoring around the livestock and poultry breeding area.

[0004] The premise of realizing soil environment monitoring in the livestock and poultry breeding area is to obtain reasonable soil samples. The current soil sampling method is for the whole earth environment soil sphere, and only the principle requirements of point distribution and sampling are proposed, and it cannot directly guide the soil pollution monitoring of the agricultural and forestry land caused by livestock and poultry breeding. SUMMARY

[0005] The present disclosure provides a method for determining soil pollution caused by livestock and poultry breeding, comprising:

[0006] determining a livestock and poultry breeding area in a target monitoring area and a pollution monitoring area associated with the livestock and poultry breeding area, comprising: in the case that the livestock and poultry breeding area is a large-scale industrial breeding area, determining the area range of the livestock and poultry breeding area based on the boundary of the large-scale industrial breeding area; in the case that the livestock and poultry breeding area is a scattered intensive breeding area, calculating a maximum possible influence area based on the breeding quantity of various livestock and poultry in the scattered intensive breeding area and the unit pollution influence area of various livestock and poultry, wherein the unit pollution influence area of livestock and poultry is the pollution influence range of a single livestock and poultry determined in advance, and the annual manure and water discharge area of a single livestock and poultry can be used as the unit pollution influence area, the unit pollution influence area of various livestock and poultry and the breeding quantity of various livestock and poultry in the scattered intensive breeding area are weighted and summed to obtain the maximum possible influence area; determining the area range of the target monitoring area based on the maximum possible influence area and the geographical features of the region where the scattered intensive breeding area is located; determining the area of the scattered intensive breeding area based on the breeding quantity of various livestock and poultry in the scattered intensive breeding area and the unit breeding density of pollution of various livestock and poultry, determining the center position of the scattered intensive breeding area based on the distribution characteristics of the scattered intensive breeding area, and determining the area range of the livestock and poultry breeding area based on the center position of the scattered intensive breeding area and the area of the scattered intensive breeding area; and taking the remaining area of the target monitoring area or the area affected by the livestock and poultry breeding area as the pollution monitoring area;

[0007] dividing the pollution monitoring area into a key monitoring area and a non-key monitoring area based on the location of the livestock and poultry breeding area in the pollution monitoring area and geographical features of the pollution monitoring area, wherein the key monitoring area is an area significantly affected by livestock and poultry breeding pollution emissions;

[0008] determining sampling points in the key monitoring area according to a first distribution method, determining sampling points in the non-key monitoring area according to a second distribution method, and sampling according to the sampling points to obtain soil samples; the distribution density in the first distribution method is greater than the distribution density in the second distribution method;

[0009] detecting pollutants in the soil samples to obtain pollutant data for each sampling point, and inferring soil pollution conditions in the pollution monitoring area caused by livestock and poultry breeding area emissions based on the pollutant data, further comprising: determining characteristic pollutants according to the types of livestock and poultry bred in the livestock and poultry breeding area, feed additives for livestock and poultry breeding, and the type of agricultural land in the pollution monitoring area; the characteristic pollutants are pollutants that are more difficult to be absorbed by crops or naturally degraded; detecting pollutants in the soil samples to obtain pollutant data for each sampling point, including: detecting the characteristic pollutants in the soil samples to obtain concentration data of the characteristic pollutants; the inferring of soil pollution conditions in the pollution monitoring area caused by livestock and poultry breeding area emissions based on the pollutant data includes: inferring soil pollution conditions in the pollution monitoring area caused by livestock and poultry breeding area emissions based on the concentration data of the characteristic pollutants.

[0010] Optionally, dividing the pollution monitoring area into a key monitoring area and a non-key monitoring area based on the location of the livestock and poultry breeding area in the pollution monitoring area and geographical features of the pollution monitoring area includes:

[0011] determining a downstream direction area of the livestock and poultry breeding area based on the location of the livestock and poultry breeding area in the pollution monitoring area and the geographical features of the pollution monitoring area;

[0012] circumscribing the key monitoring area in the downstream direction area, and taking the area of the pollution monitoring area other than the key monitoring area as the non-key monitoring area.

[0013] Optionally, determining sampling points in the key monitoring area according to a first distribution method includes:

[0014] In the key monitoring area, the sampling points are determined in a manner that the distribution spacing gradually increases from close to the livestock and poultry breeding area to far away from the livestock and poultry breeding area according to the direction of surface runoff.

[0015] Optionally, sampling according to the sampling points to obtain soil samples includes:

[0016] determining a typical crop root depth of the pollution monitoring area, and determining a surface layer depth, a middle layer depth and a bottom layer depth according to the typical crop root depth; the surface layer depth is a depth above a main root layer of the typical crop; the middle layer depth is a depth of the main root layer of the typical crop; and the bottom layer depth is a depth that cannot be reached by the root of the typical crop;

[0017] sampling soil at the surface layer depth, the middle layer depth and the bottom layer depth of each sampling point to obtain soil samples at the corresponding depths;

[0018] deducing a soil pollution condition caused by pollution discharge of the livestock and poultry breeding area in the pollution monitoring area based on the pollutant data, including: determining a migration of the pollutant in a depth direction of the soil based on the pollutant data corresponding to the soil samples at different depths of each sampling point.

[0019] Optionally, the sampling of the soil at the surface layer depth, the middle layer depth and the bottom layer depth of each sampling point to obtain soil samples at the corresponding depths includes:

[0020] sampling the soil at the surface layer depth, the middle layer depth and the bottom layer depth of each sampling point to obtain soil samples at the corresponding depths before the rainfall, after the rainfall and when the rainwater recedes and there is no water accumulation at the sampling point;

[0021] The determining of the migration of the pollutant in the depth direction of the soil based on the pollutant data corresponding to the soil samples at different depths of each sampling point includes: determining a migration of the pollutant caused by rainwater infiltration based on the pollutant data corresponding to the soil samples before and after the rainfall of each sampling point.

[0022] Optionally, the method further includes: determining an upstream monitoring area of the target monitoring area according to geographical features, and determining a sampling control point in the upstream monitoring area;

[0023] sampling at the sampling control point to obtain a control soil sample, and detecting the control soil sample to obtain control data;

[0024] The deducing of the soil pollution condition caused by pollution discharge of the livestock and poultry breeding area in the pollution monitoring area based on the pollutant data includes: taking the control data as a reference, and deducing the soil pollution condition caused by pollution discharge of the livestock and poultry breeding area in the pollution monitoring area according to the pollutant data of each sampling point.

[0025] Optionally, the sampling points in the non-key monitoring area are determined according to a second sampling method, including: according to a possible pollution degree estimated according to the topographic features of the non-key monitoring area, one of a diagonal line method, a quincunx method, a chessboard method or a snake method and a corresponding sampling density are used to determine the sampling points.

[0026] The embodiment of the present disclosure determines the livestock and poultry breeding area and the corresponding pollution monitoring area, and then divides the pollution monitoring area into a key monitoring area and a non-key monitoring area based on the geographical features of the livestock and poultry breeding area and the pollution area. Sampling points are determined for the key monitoring area and the non-key monitoring area, respectively, and soil samples are obtained by sampling at the sampling points. Then, the soil pollution condition of the pollution monitoring area is inferred according to the pollutant data obtained by detecting the soil samples. The embodiment of the present disclosure proposes a sampling scheme with guiding value for livestock and poultry breeding, and the determined soil pollution condition can reflect the influence of the distribution characteristics caused by geographical features. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without creative labor, wherein:

[0029] Figure 1 is a flow chart of the method for determining the soil pollution condition caused by livestock and poultry breeding pollution provided by the embodiment of the present disclosure;

[0030] Figure 2 is a flow chart of the method for determining the key monitoring area in a specific application. DETAILED DESCRIPTION

[0031] The embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms, and should not be interpreted as being limited to the embodiments described herein, but rather, these embodiments are provided to more thoroughly and completely understand the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes, and are not intended to limit the scope of protection of the present disclosure.

[0032] As used herein, the term "includes" and its variants are open, i.e., "includes but is not limited to." The term "based on" means "based at least in part on." The term "one embodiment" means "at least one embodiment." The term "another embodiment" means "at least one additional embodiment." The term "some embodiments" means "at least some embodiments." Related terms have corresponding definitions. In this document, relational terms such as "first" and "second" and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0033] The embodiments of the present disclosure provide a soil pollution condition determination method for livestock and poultry breeding pollution. Figure 1 is a flow chart of the soil pollution condition determination method for livestock and poultry breeding pollution provided by the embodiments of the present disclosure. As shown in Figure 1 The soil pollution condition determination method provided by the embodiments of the present disclosure includes S110-S140.

[0034] S110: Determine the livestock and poultry breeding area in the target monitoring area and the pollution monitoring area associated with the livestock and poultry breeding area.

[0035] The target monitoring area is the agricultural and forestry land with livestock and poultry breeding area in its range, and various wastes discharged by the livestock and poultry breeding area may pollute it. In specific implementation, the target monitoring area can be determined according to the agricultural industry conditions of each region. For example, in a certain county-level administrative region, if there is a larger scale of livestock and poultry breeding output or output value in the concentrated agricultural land area, the aforementioned concentrated agricultural land area can be regarded as the target monitoring area.

[0036] After determining the target monitoring area, the livestock and poultry breeding area and the pollution monitoring area associated with the livestock and poultry breeding area in the target monitoring area can be determined according to specific conditions. The premise of determining the pollution monitoring area is to determine the livestock and poultry breeding area. In actual application, the method of determining the livestock and poultry breeding area may be different. In specific conditions, the livestock and poultry breeding area may be a large-scale industrial breeding area (such as a large-scale pig farm or chicken farm), or a scattered breeding area (such as a village with more individual livestock and poultry breeders).

[0037] In the case of livestock and poultry breeding area as a large-scale industrial breeding area, since the aforementioned industrial breeding area generally needs to be planned as industrial land, and the range of the industrial breeding area is strictly limited by the range of the industrial land planning, the area determined based on the boundary of the industrial breeding area can be regarded as the area range of the corresponding livestock and poultry breeding area. That is, in the case of livestock and poultry breeding area as a large-scale industrial breeding area, the factory area of the large-scale industrial breeding area can be directly regarded as the area range of the corresponding livestock and poultry breeding area.

[0038] In the case of livestock and poultry breeding area is scattered intensive area, there is no directly determinable boundary for determining the range of breeding area. To solve this problem, the embodiments of the present disclosure consider using the following method to determine the area range of livestock and poultry breeding area: determining the area of the scattered intensive area based on the breeding amount of various livestock and poultry in the scattered intensive area and the unit breeding density of various livestock and poultry, determining the center position of the scattered intensive area based on the distribution characteristics of the scattered intensive area, and then determining the area range of the livestock and poultry breeding area based on the center position of the scattered intensive area and the area of the scattered intensive area. For example, a scattered intensive area raises about 10,000 chickens, and it is generally determined that the breeding density of the scattered chickens is in the range of 100 , then it is highly probable that the area of this scattered intensive area is 10,000*100=1,000,000 (such as 1 square kilometer). In specific implementation, the distribution of each scattered breeder can be generally determined based on the distribution range of each scattered breeder, and accordingly the center position of the scattered intensive area can be generally determined. After determining the center position and area of the scattered intensive area, the area range of livestock and poultry breeding in the intensive scattered manner can be determined based on the center position and area according to a specific shape type (for example, a radial fan shape, a rectangle, etc., which is specific to the distribution type of the breeder).

[0039] After determining the range of the livestock and poultry breeding area, the area of the target monitoring area except the livestock and poultry breeding area can be regarded as the pollution monitoring area, or the area of the target monitoring area affected by the livestock and poultry breeding area can be regarded as the pollution monitoring area according to experience.

[0040] S120: dividing the pollution monitoring area into a key monitoring area and a non-key monitoring area based on the position of the livestock and poultry breeding area in the pollution monitoring area and the geographical characteristics of the pollution monitoring area.

[0041] The key monitoring area is an area significantly affected by livestock and poultry breeding pollution emissions. Accordingly, the non-key monitoring area is an area in the pollution monitoring area except the key monitoring area.

[0042] In the embodiments of the present disclosure, the pollution monitoring area is divided into a key monitoring area and a non-key monitoring area based on the position of the livestock and poultry breeding area in the pollution monitoring area and the geographical characteristics of the pollution monitoring area, which can determine the area downstream of the livestock and poultry breeding area as the key monitoring area in combination with the position of the livestock and poultry breeding area in the pollution monitoring area, the surface water flow direction of the pollution monitoring area, or the surface elevation model (these data reflect the geographical characteristics of the target detection area).

[0043] In addition, considering that groundwater can also serve as an important pollution diffusion path to realize the collection and diffusion of pollutants, the groundwater flow direction is also considered to determine the key monitoring area in some applications.

[0044] Figure 2is a flow chart of a method for determining a key monitoring area in a specific application. As shown in Figure 2 the livestock and poultry breeding area in this specific application is a large-scale industrial breeding area, and its range is determined by the boundary of the breeding farm. According to the flow direction of surface runoff and groundwater in the pollution monitoring area, the fan-shaped area or rectangular area located in the left and lower areas of the livestock and poultry breeding area is determined as the key monitoring area, and the corresponding other areas are determined as non-key monitoring areas.

[0045] In summary, the following S121-S122 can be used to determine the key monitoring area and the non-key monitoring area in the specific implementation.

[0046] S121: Based on the location of the livestock and poultry breeding area in the pollution monitoring area and the geographical features of the pollution monitoring area, determine the downstream direction area of the livestock and poultry breeding area.

[0047] S122: Circle the key monitoring area in the downstream direction area, and the area outside the key monitoring area in the pollution monitoring area as the non-key monitoring area.

[0048] The downstream direction mentioned here refers to the downstream direction of the river flow or the surface runoff in the case of river or rainfall forming surface runoff. The corresponding downstream direction area is the area in the pollution monitoring area corresponding to the downstream direction.

[0049] S130: Determine the sampling point in the key monitoring area according to the first layout method, determine the sampling point in the non-key monitoring area according to the second layout method, and sample according to the sampling point to obtain soil samples.

[0050] The first layout method is the layout method corresponding to the sampling point in the key monitoring area, and the second layout method is the layout method corresponding to the sampling point in the non-key monitoring area. The sampling density in the first layout method is greater than that in the second layout method. That is, compared with the non-key monitoring area, the key monitoring area will use higher sampling density for sampling, so as to obtain more typical data reflecting the distribution state of pollutants.

[0051] As previously analyzed, because the key monitoring area is determined according to the geographical features (specifically according to the terrain and surface runoff) and is located in the downstream area of the livestock and poultry breeding area, and considering that the diffusion of pollutants may slow down as the concentration of pollutants decreases, in the embodiment of the present disclosure, for the key monitoring area, the sampling point can be determined in the direction of surface runoff, with the spacing gradually increasing from close to the livestock and poultry breeding area to far away from the livestock and poultry breeding area.

[0052] As shown in Figure 2As shown, in one embodiment, from the direction close to the livestock and poultry breeding area to the direction away from the livestock and poultry breeding area, the distance from the sampling point to the boundary of the livestock and poultry breeding area is 40m, 100m, 200m, 500m and 1000m in turn, which embodies the feature of gradually increasing spacing between points. In addition, in specific implementation, in the direction perpendicular to the runoff of the key monitoring area, the points can be distributed in a fan-shaped manner to be able to reflect the fan-shaped diffusion of pollutants that may occur.

[0053] For non-key monitoring areas, diagonal line method, plum blossom point method, chessboard method or snake-shaped method can be used to determine the sampling points, which can be determined according to the topographic features and the possible degree of soil pollution of the non-key area. Among them, the diagonal line method is suitable for flat terrain and relatively uniform pollution areas, which is specifically divided into single diagonal line method and double diagonal line method; the plum blossom point method is suitable for relatively large, flat terrain and relatively uniform soil pollution areas; the chessboard method is suitable for medium-sized, flat terrain and soil pollution areas with some differences; the snake-shaped method is suitable for narrow, uneven terrain, large area and soil pollution areas with some differences.

[0054] In specific implementation, the sampling points can be determined in terms of longitude and latitude information, or in terms of distance and angle with reference to a specific position point.

[0055] After determining the sampling points, the sampling points can be distributed and sampled to obtain soil samples. It should be noted here that the actual sampling points may have some positional deviation from the pre-determined sampling points according to the specific circumstances, but the aforementioned positional deviation will not be too large. In addition, in order to adapt to the detection of different types of pollutants later, multiple soil samples with basically corresponding properties can be collected at one sampling point.

[0056] S140: detecting the pollutants of the soil samples to obtain the pollutant data of each sampling point, and inferring the soil pollution status of the pollution monitoring area caused by the pollution of the livestock and poultry breeding area based on the pollutant data.

[0057] After obtaining the soil samples of each sampling point, the corresponding detection method can be used to detect the pollutants of the soil samples to obtain the pollutant data of each sampling point.

[0058] In specific implementation, the project of monitoring the pollutants in the soil samples according to some regulations at least includes: total nitrogen, total phosphorus, available phosphorus, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and additionally can include heavy metals, antibiotics, estrogens (such as chicken farms targeting egg production), peptide acid esters, alkyl phenols, microplastics, and the like. In specific implementation, the pollutants can be determined according to the soil type, crop type, planting cycle, irrigation frequency of the pollution monitoring area, and the livestock and poultry type, feed type, feeding frequency of the livestock and poultry breeding area, and then the corresponding detection method is used to monitor the pollutants in the soil samples to obtain the pollutant data.

[0059] After obtaining the pollutant data of each sampling point, a mathematical simulation method can be used to simulate and simulate the pollutant data corresponding to each sampling point, to infer the soil pollution condition of the entire pollution monitoring area, and to determine the soil pollution condition caused by the livestock and poultry breeding area based on the agricultural operation condition (such as fertilization, irrigation) of the pollution monitoring area.

[0060] As analyzed before, considering the actual situation of livestock and poultry breeding polluting farmland and forest land, after determining the livestock and poultry breeding area and the corresponding pollution monitoring area in the embodiments of the present disclosure, the pollution monitoring area is divided into a key monitoring area and a non-key monitoring area based on the geographical features of the livestock and poultry breeding area and the pollution area. Sampling points are determined for the key monitoring area and the non-key monitoring area, soil samples are obtained by sampling at the sampling points, and the soil pollution condition of the pollution monitoring area is inferred according to the pollutant data obtained by detecting the soil samples. The sampling scheme of the present disclosure has guiding value for livestock and poultry breeding, and can make the determined soil pollution condition reflect the influence of the distribution characteristics caused by geographical features.

[0061] According to the existing livestock and poultry breeding investigation, it is found that the large-scale industrial breeding area generally adopts reasonable pollution control measures to avoid direct discharge of livestock and poultry excrement (but performs composting fermentation, sewage treatment, etc.). In this case, the size of the target monitoring area and the livestock and poultry breeding quantity of the large-scale industrial breeding area are not directly related, and there is no need to consider the pollution area caused by the livestock and poultry breeding quantity. In the case of livestock and poultry breeding area as a scattered intensive area (that is, livestock and poultry breeding as a small-scale scattered individual), due to the scale and cost limitations, livestock and poultry excrement may be discharged without harmless treatment. In this case, the livestock and poultry breeding scale directly determines the range that may be affected by pollution (the more the livestock and poultry quantity, the wider the influence range).

[0062] Based on the above considerations, in the case of livestock and poultry breeding area as a scattered intensive area, some embodiments also perform S150-S160 as follows.

[0063] S150: Calculate the maximum possible influence area based on the breeding quantity of various livestock and poultry in the free-range dense area and the unit pollution influence area of various livestock and poultry.

[0064] S160: Determine the regional range of the target monitoring area based on the maximum possible influence area and the geographical features of the region where the free-range dense area is located.

[0065] The unit pollution influence area of livestock and poultry is the pollution influence range of a single head / individual livestock and poultry, which can be the fertilizable land area of the annual manure and water discharge of a single head / individual livestock and poultry in specific implementation. Through a rough estimate, 1 chicken can fertilize about 4m 2 land per year, 1 duck can fertilize about 5m 2 land per year, 1 pig can fertilize about 150m 2 land per year, 1 sheep can fertilize about 200m 2 land per year, and 1 cow can fertilize about 0.04 km 2 land per year. By weighting and summing the unit pollution influence area of various livestock and poultry and the breeding quantity of various livestock and poultry in the free-range dense area, the maximum possible influence area can be obtained. After obtaining the maximum possible influence area, the regional range of the target monitoring area can be determined based on the maximum possible influence area and the geographical features of the region where the free-range dense area is located.

[0066] As mentioned in S130, soil samples are obtained by sampling according to the sampling points. In specific implementation, after determining the sampling points, how to sample to obtain soil samples has a great influence on the pollutant data in the soil samples obtained later, and a reasonable soil sampling strategy needs to be developed.

[0067] In one specific implementation, the soil samples can be obtained by sampling according to the sampling points in the following S131-S132.

[0068] S131: Determine the typical crop root depth of the pollution monitoring area, and determine the surface depth, middle depth and bottom depth according to the typical crop root depth.

[0069] From the perspective of agricultural planting, pollutants such as total nitrogen, total phosphorus, available phosphorus, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, etc. can be directly used as agricultural fertilizers or used as agricultural fertilizers after redox. After the foregoing pollutants enter the soil, the content in the soil meets the actual situation of agricultural production, and the absorption of agricultural and forestry crops will not have a large content. Based on this, in addition to the surface soil, the root depth of crops will directly affect the content of the foregoing types of pollutants in the corresponding soil layer. Based on this, the surface depth, the middle depth and the bottom depth need to be determined in combination with the typical crop root depth in the embodiments of the present disclosure. The surface depth is the depth above the main root system of the typical crop, the middle depth is the depth where the main root system of the typical crop is located, and the bottom depth is the depth that the root system of the typical crop cannot reach.

[0070] For example, in one specific application, according to the typical crop root depth determined by on-site excavation analysis, the surface depth is determined to be 0-20 cm, the middle depth is determined to be 20-40 cm, and the bottom depth is determined to be 40-60 cm.

[0071] S132: Sampling the soil at the corresponding depth position according to the surface depth, the middle depth and the bottom depth at the sampling point, to obtain the soil sample at the corresponding depth.

[0072] After determining the surface depth, the middle depth and the bottom depth, a reasonable soil sampling method can be determined for soil sampling at the determined sampling depth, to obtain the soil sample at the corresponding depth.

[0073] In the case of determining the soil sample by using the foregoing S131-S132 method and detecting the soil sample to obtain the pollutant data, S140 is specifically based on the pollutant data corresponding to the soil sample at different depths of each sampling point to determine the migration of the pollutant in the depth direction of the soil. Based on the pollutant data corresponding to the soil sample at different depths of each sampling point, the migration of the pollutant in the depth direction of the soil can be determined, which can inversely deduce whether the emission amount of pollutants such as nitrogen and phosphorus is seriously excessive, and further estimate whether there is a situation of pollutant over-discharge or even discharge without treatment.

[0074] The migration of pollutants in the soil includes passive migration under the action of water in addition to diffusion migration caused by concentration difference. To obtain the migration of pollutants caused by rain, in the implementation, when S132 is performed, the soil at the corresponding depth can be sampled according to the surface depth, the middle depth and the bottom depth of each sampling point before, after and when the rainwater recedes and there is no accumulated water at the sampling point, to obtain the soil samples at the corresponding depth before and after the rain. Correspondingly, the comparison and analysis of the pollutant data corresponding to the soil samples at different depths of each sampling point in S140 can determine the migration of pollutants caused by rainwater leakage, and further consider the impact of pollutant discharge in the rainy season and flood season on groundwater and the enrichment of pollutants in the deep soil.

[0075] As analyzed before, pollutants such as nitrogen and phosphorus are pollutants that can be absorbed by crops to achieve removal, and it is not appropriate to use the concentration data of such pollutants to identify the diffusion path of pollutants in the pollution monitoring area. Based on this, in some embodiments of the present disclosure, the determination of the diffusion path of pollutants in the pollution monitoring area based on the data of specific types of pollutants is considered, specifically including S170 as follows.

[0076] S170: determining a characteristic pollutant according to the types of livestock and poultry raised in the livestock and poultry breeding area, the feed additives of the livestock and poultry, and the types of agricultural land in the pollution monitoring area; the characteristic pollutant is a pollutant that is more difficult to be absorbed by crops or biodegraded.

[0077] The characteristic pollutant in the embodiments of the present disclosure is a pollutant that is more difficult to be absorbed by crops or biodegraded. Different types of livestock and poultry have different feeding value targets, and the types of feed and breeding cycles of different livestock and poultry are different, and the corresponding feeding strategies and the use of feed additives, antibiotics and the like are different. Accordingly, the characteristic pollutant needs to be determined according to the types of livestock and poultry raised in the livestock and poultry breeding area and the feed additives. For example, in the case of breeding laying hens in the livestock and poultry breeding area, to ensure high egg production efficiency of the laying hens, there will be estrogen in the feed additives; in the case of breeding meat chickens in the livestock and poultry breeding area, there will be no estrogen in the feed additives. For another example, livestock and poultry such as chickens, ducks and pigs are mainly fed with grains, while livestock and poultry such as cattle and sheep are mainly fed with grass, and the enrichment of various types of pollutants in the two different types of feed is different, and the types of corresponding characteristic pollutants are also different.

[0078] Furthermore, different types of agricultural land are planted with different types of crops (including trees), and the root systems of these crops and their ability to accumulate pollutants vary. Therefore, it is necessary to consider the agricultural land type when determining characteristic pollutants. In a specific application, if the pollution monitoring area is arable land, rubber plantation, or tea garden, characteristic pollutants may include antibiotics and estrogens; if the pollution monitoring area is orchard or vegetable garden, characteristic pollutants may include antibiotics, phthalates, microplastics, estrogens, and alkylphenols.

[0079] In addition to performing S170, S140 also includes detecting characteristic pollutants in the soil sample to obtain concentration data of the characteristic pollutants. With the concentration data of the characteristic pollutants obtained, the soil pollution status caused by sewage discharge from livestock and poultry farming areas in the pollution monitoring area can be inferred based on this data. Specifically, this involves determining the diffusion path and severity of the pollutants in the pollution monitoring area.

[0080] Undeniably, pollutants in the pollution monitoring area may not be solely caused by discharges from livestock and poultry farms; they could also originate from other upstream pollution sources. Therefore, when determining the pollution level caused by discharges from livestock and poultry farms based on pollution data, it is necessary to rule out other causes. For agricultural and forestry land, aside from fertilizer and pesticide application, there are not many other pollutants. While fertilizer and pesticide application can be inferred from corresponding soil pollutant data, the key issue is excluding pollutants from other sources.

[0081] like Figure 2 As shown, in some embodiments of this disclosure, in addition to determining the sampling points of the target monitoring area, an upstream monitoring area is also determined based on geographical features, and a sampling control point is determined within the upstream monitoring area. Specifically, the sampling control point can be set up in an area adjacent to the edge of the target monitoring area. After determining the sampling control point, it is necessary to conduct sampling at the control point to obtain control soil samples, and then monitor the pollutants on the control soil samples to obtain control data. With control data available, the determination of soil pollution status in step S140 above specifically involves using the control data as a reference and inferring the soil pollution status caused by sewage discharge from livestock and poultry farming areas in the pollution monitoring area based on the pollutant data from each sampling point.

[0082] The above are merely specific embodiments of this disclosure, enabling those skilled in the art to understand or implement this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to these embodiments, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining soil pollution conditions caused by livestock and poultry breeding sewage, characterized in that, The method comprises the following steps: determining a livestock and poultry breeding area in a target monitoring area and a pollution monitoring area associated with the livestock and poultry breeding area, including: in the case that the livestock and poultry breeding area is a large-scale industrial breeding area, determining the area range of the livestock and poultry breeding area based on the boundary of the large-scale industrial breeding area; in the case that the livestock and poultry breeding area is a scattered intensive area, calculating the maximum possible influence area based on the breeding quantity of various livestock and poultry in the scattered intensive area and the unit pollution influence area of various livestock and poultry, wherein the unit pollution influence area of livestock and poultry is the pre-determined pollution influence range of a single livestock and poultry, and the manure and water discharge quantity of a single livestock and poultry per year is used as the unit pollution influence area, and the unit pollution influence area of various livestock and poultry and the breeding quantity of various livestock and poultry in the scattered intensive area are weighted and summed to obtain the maximum possible influence area; determining the area range of the target monitoring area based on the maximum possible influence area and the geographical features of the region where the scattered intensive area is located; determining the area of the scattered intensive area based on the breeding quantity of various livestock and poultry in the scattered intensive area and the unit breeding density of pollution of various livestock and poultry, determining the center position of the scattered intensive area based on the distribution characteristics of the scattered intensive area, and determining the area range of the livestock and poultry breeding area based on the center position of the scattered intensive area and the area of the scattered intensive area; and taking the remaining area of the target monitoring area or the area affected by the livestock and poultry breeding area as the pollution monitoring area; dividing the pollution monitoring area into a key monitoring area and a non-key monitoring area based on the position of the livestock and poultry breeding area in the pollution monitoring area and the geographical features of the pollution monitoring area, wherein the key monitoring area is an area significantly affected by livestock and poultry breeding pollution discharge; determining sampling points in the key monitoring area according to a first distribution method, determining sampling points in the non-key monitoring area according to a second distribution method, and sampling according to the sampling points to obtain soil samples; the distribution density in the first distribution method is greater than the distribution density in the second distribution method; detecting pollutants in the soil samples to obtain pollutant data of each sampling point, and inferring the soil pollution condition of the pollution monitoring area caused by livestock and poultry breeding area pollution discharge based on the pollutant data, further comprising: determining characteristic pollutants according to the types of livestock and poultry bred in the livestock and poultry breeding area, feed additives for livestock and poultry breeding, and the types of agricultural land in the pollution monitoring area; the characteristic pollutants are pollutants that are more difficult to be absorbed by crops or naturally degraded; detecting the characteristic pollutants in the soil samples to obtain concentration data of the characteristic pollutants; and inferring the soil pollution condition of the pollution monitoring area caused by livestock and poultry breeding area pollution discharge based on the concentration data of the characteristic pollutants.

2. The method of claim 1, wherein, dividing the pollution monitoring area into a key monitoring area and a non-key monitoring area based on the position of the livestock and poultry breeding area in the pollution monitoring area and the geographical features of the pollution monitoring area, including: determining a downstream direction area of the livestock and poultry breeding area based on a position of the livestock and poultry breeding area in the pollution monitoring area and geographical features of the pollution monitoring area; circumscribing the key monitoring area in the downstream direction area, and taking an area of the pollution monitoring area other than the key monitoring area as the non-key monitoring area.

3. The method according to any of claims 1-2, characterized in that, determining sampling points in the key monitoring area according to a first distribution mode, including: in the key monitoring area, determining sampling points in a manner that a distribution interval gradually increases from close to the livestock and poultry breeding area to far away from the livestock and poultry breeding area according to a surface runoff direction.

4. The method according to any one of claims 1-2, characterized in that, distributing and sampling according to the sampling points to obtain soil samples, including: determining a typical crop root depth of the pollution monitoring area, and determining a surface depth, an intermediate depth and a bottom depth according to the typical crop root depth; the surface depth is a depth above main roots of the typical crop; the intermediate depth is a depth where the main roots of the typical crop are located, and the bottom depth is a depth that the roots of the typical crop cannot reach; sampling soil at corresponding depth positions according to the surface depth, the intermediate depth and the bottom depth at the sampling points to obtain soil samples at corresponding depths; deducing a soil pollution condition of the pollution monitoring area caused by pollution discharge of the livestock and poultry breeding area based on the pollutant data, including: determining a migration of the pollutant in a soil depth direction based on the pollutant data corresponding to the soil samples at different depths of each sampling point.

5. The method of claim 4, wherein, sampling soil at corresponding depth positions according to the surface depth, the intermediate depth and the bottom depth at the sampling points to obtain soil samples at corresponding depths, including: sampling soil at corresponding depths according to the surface depth, the intermediate depth and the bottom depth at each sampling point respectively before rainfall, after rainfall and when rainwater recedes and there is no water accumulation at the sampling points to obtain soil samples at corresponding depths before and after rainfall; the determining of the migration of the pollutant in the soil depth direction based on the pollutant data corresponding to the soil samples at different depths of each sampling point, including: determining a migration of the pollutant caused by rainwater infiltration based on the pollutant data corresponding to the soil samples before and after rainfall at each sampling point.

6. The method according to any one of claims 1-2, characterized in that, further including: determining an upstream monitoring area of the target monitoring area according to the geographical features, and determining sampling control points in the upstream monitoring area; distributing and sampling at the sampling control points to obtain control soil samples, and detecting the control soil samples to obtain control data; the deducing of the soil pollution condition of the pollution monitoring area caused by pollution discharge of the livestock and poultry breeding area based on the pollutant data, including: taking the control data as a reference, and deducing the soil pollution condition of the pollution monitoring area caused by pollution discharge of the livestock and poultry breeding area according to the pollutant data of each sampling point.

7. The method according to any one of claims 1-2, characterized in that, determining sampling points in the non-key monitoring area according to a second distribution mode, including: according to a possible pollution degree estimated according to topographic features of the non-key monitoring area, determining the sampling points by using one of a diagonal line method, a quincunx point method, a chessboard type method or a snake shape method and a corresponding distribution density.

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