Livestock manure land bearing capacity calculation method

Abstract

The application provides a livestock and poultry manure land carrying capacity calculation method, relates to the technical field of land carrying capacity calculation, and can comprehensively reflect the space-time distribution of pollutants in the soil and the synergistic effect of the pollutants on microbial activity and nutrient conversion by establishing a kinetic model of microplastic migration and antibiotic inhibition, and generate a synergistic correction factor that can reflect the actual pollution condition of the soil on the basis, so that dynamic correction of the soil carrying capacity is realized. Meanwhile, the carrying capacity of the key root zone is accurately evaluated in combination with the growth depth of the target crops, the manure application amount is adjusted accordingly, and the management strategy of increasing, reducing or keeping the manure application amount is dynamically formulated by comparison with the recommended carrying capacity interval, so that the manure resource utilization is more scientific and environment-friendly, and the nutrient supply and ecological safety level of the farmland are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of land carrying capacity calculation, in particular to a livestock and poultry manure land carrying capacity calculation method. BACKGROUND

[0002] With the rapid development of modern livestock and poultry breeding industry, the reasonable disposal and resource utilization of livestock and poultry manure have become an important issue for agricultural ecological environment protection. However, livestock and poultry manure often contains microplastic particles and antibiotics and other pollutants. These substances enter the soil through manure, affecting the physical structure and microbial activity of the soil, and then interfering with nutrient cycling and soil health, and reducing the sustainable use of land. The existing land carrying capacity assessment relies on traditional nutrient element model, and does not fully consider the synergistic effect of microplastics and antibiotics, lacks scientific simulation of the dynamic process of pollutant migration and microbial inhibition, resulting in a large difference between the carrying capacity assessment results and the actual ecological risk. In addition, the precise fertilization regulation scheme for different soil depths and crop growth needs has not been formed, which limits the safe and efficient use of livestock and poultry manure resources, and is difficult to meet the demand of modern agriculture for environment-friendly management.

[0003] In the prior art, the publication number CN116340698A discloses a livestock and poultry manure land carrying capacity calculation method, which includes the following steps: S1. Multiply the regional plant nutrient demand, the fertilizer supply proportion and the manure fertilizer ratio, and then divide by the manure utilization rate in the season to obtain the regional plant manure nutrient demand; S2. Divide the total supply of regional livestock and poultry manure nutrients by the total pig equivalent to obtain the unit pig equivalent manure nutrient supply; S3. Divide the regional plant manure nutrient demand by the unit pig equivalent manure nutrient supply to obtain the livestock and poultry manure land carrying capacity. Although this scheme can calculate the land carrying capacity, it focuses on the static estimation of nutrient supply and demand, lacks dynamic modeling of the migration and ecological impact of pollutants such as microplastics and antibiotics, and is difficult to reflect the complex synergistic effect of livestock and poultry manure on soil function, and does not combine soil depth and crop root zone characteristics for precise correction, resulting in insufficient scientificity and refinement of carrying capacity assessment and manure application scheme.

[0004] The above information disclosed in the background section is only used to enhance the understanding of the background of the present disclosure, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] The purpose of the present application is to provide a livestock and poultry manure land carrying capacity calculation method to solve the problems raised in the background.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] A livestock and poultry manure land carrying capacity calculation method, the specific steps comprising:

[0008] S1: Set sampling points in the pollution area and the non-pollution area respectively, collect soil quality parameters, microplastic concentration, antibiotic concentration, and microbial activity indicators at different soil depths, and establish a microplastic migration model and an antibiotic inhibition kinetics model related to depth;

[0009] S2: Based on the microplastic migration model and the antibiotic inhibition kinetics model, generate a microplastic-antibiotic synergistic correction factor related to soil depth, which is used to reflect the synergistic effect of microplastics and antibiotics on land carrying capacity;

[0010] S3: Calculate the initial carrying capacity of the land using the NPK model, and use the microplastic-antibiotic synergistic correction factor to correct the initial carrying capacity to obtain a corrected carrying capacity related to soil depth;

[0011] S4: Based on the optimal planting depth of the target crop, obtain the corrected carrying capacity of the target crop at the optimal planting depth, and compare the corrected carrying capacity with a preset recommended carrying capacity range, and generate a manure dosage control strategy based on the comparison result.

[0012] Preferably, the soil quality parameters include but are not limited to soil pore water content and soil water flow velocity.

[0013] The logic for collecting microplastic concentration is as follows:

[0014] After soil flotation, microplastic particles are separated, and fluorescence microscopy is used to image microplastic particles with a diameter greater than 100 microns.

[0015] The characteristic spectrum of the microplastic particles is collected by near-infrared spectroscopy, and compared with the standard spectrum library to classify and count the types and quantities of microplastic particles.

[0016] The microplastic concentration is calculated based on the type, quantity, and volume of the microplastic particles, defined as the ratio between the total mass of all microplastic particles and the mass of the soil.

[0017] Preferably, the microplastic migration model is constructed based on the first-order convection-diffusion equation, which is used to reflect the trend of microplastic concentration changing with time at different soil depths, and its function expression is as follows:

[0018] ;

[0019] In the formula, represents the microplastic concentration at soil depth at time , , and , , respectively These represent the equivalent diffusion coefficient of microplastics in soil, soil water flow velocity, and degradation rate, respectively.

[0020] Preferably, the logic for obtaining the equivalent diffusion coefficient is as follows:

[0021] Calculate the average radius of all microplastic particles that meet the imaging conditions;

[0022] Substituting the average radius into the Stokes-Einstein equation, the free water diffusion coefficient of microplastics in pure water was calculated.

[0023] The free water diffusion coefficient is corrected based on soil pore water content and a preset diffusion path coefficient, and the product of the three is used as the equivalent diffusion coefficient of microplastics in soil.

[0024] Preferably, the microbial activity indicators include, but are not limited to, carbon dioxide release, enzyme activity, and microbial abundance, used to calculate the antibiotic inhibition rate to reflect the inhibitory effect of antibiotics on microorganisms in the soil.

[0025] The antibiotic inhibition kinetic model is constructed based on a first-order generation-decrease kinetic model to reflect the changing trend of antibiotic inhibition rate over time at different soil depths. Its functional expression is as follows:

[0026] ;

[0027] In the formula , They represent time. At that time, the soil depth was The antibiotic inhibition rate and antibiotic concentration at the site, wherein the antibiotic inhibition rate is calculated from microbial activity indicators. , These represent the suppression of generation rate constant and the suppression of decay rate constant, respectively.

[0028] Preferably, the logic for obtaining the antibiotic inhibition rate is as follows:

[0029] Soil samples from the non-polluted area were used as a control group. When collecting microbial activity indicators from the polluted area, microbial activity indicators from the non-polluted area were also collected.

[0030] Using the microbial activity index of the unpolluted area as a benchmark, the ratio of the difference in microbial activity index between the unpolluted area and the polluted area to the microbial activity index of the unpolluted area is used as the antibiotic inhibition rate.

[0031] Preferably, the logic for generating a soil depth-related microplastic-antibiotic synergistic corrector is as follows:

[0032] When the derivative of the microplastic concentration and the antibiotic inhibition rate in the microplastic migration model and the antibiotic inhibition kinetics model with respect to time is 0, it is considered that the land reaches a steady state;

[0033] The microplastic-antibiotic synergistic correction factor is generated based on the microplastic concentration and the antibiotic inhibition rate when the land reaches a steady state, and the function expression is:

[0034] ;

[0035] In the formula, The microplastic-antibiotic synergistic correction factor at the soil depth of , , The microplastic concentration and the antibiotic inhibition rate at the soil depth of , , The influence coefficients of the microplastic and the antibiotic, The synergistic factor between the microplastic and the antibiotic.

[0036] Preferably, the correction bearing capacity is the product of the initial bearing capacity and the microplastic-antibiotic synergistic correction factor.

[0037] Preferably, the logic of the fecal slurry dosage regulation strategy is:

[0038] When the correction bearing capacity of the target crop at the optimal planting depth is greater than the upper limit of the recommended bearing capacity interval, it is considered that the land bearing capacity is strong, the nutrient absorption and degradation function is good, and the fecal slurry dosage is increased to improve the land nutrient;

[0039] When the correction bearing capacity of the target crop at the optimal planting depth is in the recommended bearing capacity interval, it is considered that the land bearing capacity is general, the nutrient absorption and degradation function is moderate, and the fecal slurry dosage is kept unchanged;

[0040] When the correction bearing capacity of the target crop at the optimal planting depth is less than the lower limit of the recommended bearing capacity interval, it is considered that the land bearing capacity is weak, the nutrient absorption and degradation function is poor, and the fecal slurry dosage is reduced to avoid damage to the land.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] The present application can comprehensively reflect the spatio-temporal distribution of pollutants in the soil and the synergistic effect of the pollutants on microbial activity and nutrient conversion by establishing a kinetic model of microplastic migration and antibiotic inhibition, and generate a synergistic correction factor that can reflect the actual pollution condition of the soil on this basis, thereby realizing dynamic correction of the soil carrying capacity. At the same time, the carrying capacity of the key root zone is accurately evaluated in combination with the growth depth of the target crop, and the application amount of manure is adjusted accordingly, and through comparison with the recommended carrying capacity interval, a management strategy of increasing, reducing or maintaining the application amount of manure is dynamically formulated, so that the utilization of manure resources is more scientific and environmentally friendly, and the nutrient supply and ecological safety level of farmland are greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 It is a whole method flowchart of the present application. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the present application will be further described in detail below in combination with specific embodiments.

[0045] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the usual meaning understood by those skilled in the art to which the present application belongs. The words "first", "second" and similar words used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The words "include" or "contain" and similar words mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, and do not exclude other elements or objects. The words "connect" or "connected" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. The words "up", "down", "left", "right" and the like are only used to represent relative positional relationship, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0046] EMBODIMENT:

[0047] Please refer to Figure 1 The present application provides a technical scheme:

[0048] A method for calculating the land carrying capacity of livestock and poultry manure, comprising the following specific steps:

[0049] S1: Set sampling points in the pollution area and the non-pollution area respectively, collect soil quality parameters, microplastic concentration and antibiotic concentration at different soil depths in the pollution area, and establish a microplastic migration model and an antibiotic inhibition kinetics model related to depth. The sampling points can be determined according to expert experience (such as a typical sampling point (e.g. the center of the area)), or a plurality of sampling points can be set at a soil depth, and the parameters collected at each sampling point are averaged for subsequent calculation.

[0050] The soil quality parameters include but are not limited to soil pore water content and soil water flow velocity.

[0051] The logic for collecting the microplastic concentration is as follows:

[0052] The microplastic particles are separated after soil flotation, and the fluorescence microscope is used for imaging of the microplastic particles with a diameter greater than 100 microns. Compared with traditional simple screening or chemical dissolution, the flotation method is more environmentally friendly and less damaging to the morphology and composition of the microplastic particles, which can ensure the integrity of the particles. Through fluorescence staining, the contrast between the microplastic particles and organic / inorganic particles can be significantly improved, and the identification accuracy is enhanced. Quantitative imaging provides information on the morphology, quantity and spatial distribution of the microplastic particles, and improves the detection accuracy.

[0053] The characteristic spectrum of the microplastic particles is collected by near-infrared spectroscopy, and compared with the standard spectrum library to classify and count the types and quantities of the microplastic particles. The near-infrared spectroscopy technology is fast, non-destructive, and has high accuracy in identifying plastic types. By comparing with the standard spectrum library, accurate classification can be achieved, and different plastic materials (such as PE, PP, PS, etc.) can be effectively distinguished, improving the data quality.

[0054] The microplastic concentration is calculated based on the type, quantity and volume of the microplastic particles, and is defined as the ratio between the total mass of all microplastic particles and the mass of the soil. The final result is a dimensionless data between 0 and 1. The density of the microplastic particles can be obtained from their type, and the total mass of all microplastic particles can be obtained from the quantity and volume.

[0055] The microplastic migration model is based on the first-order convection-diffusion equation, which is used to reflect the trend of the microplastic concentration changing with time at different soil depths. The function expression is as follows:

[0056] ;

[0057] In the formula, C(x, t) represents the microplastic concentration at soil depth x and time t, , , , , , , , D, v, k, respectively represent the effective diffusion coefficient of microplastics in soil, soil water velocity, and degradation rate.

[0058] It can be understood that modern livestock and poultry may mix fine residues of feed packaging bags in feed during feeding process, and these residues are decomposed into microplastic particles after degradation in the digestive system of livestock and poultry, and are excreted out of the body with feces. At the same time, if the plastic bedding, plastic pipeline, plastic fence and other equipment used in the farm are mechanically worn and aged during long-term use, microplastic particles are also generated into the breeding environment and manure system. These microplastic particles are discharged into the soil with manure, which can change the soil pore structure and water retention capacity, affect the soil aeration and water retention, and thus affect the land carrying capacity. Therefore, the actual physical meaning reflected by the microplastic migration model is the process from "manure discharged into the soil" to "microplastic particles in manure diffusing and long-term existing in the soil".

[0059] The following basic assumptions are followed for the microplastic migration model:

[0060] Soil is a porous medium, and microplastic particles move in soil pore water;

[0061] The migration of microplastics is mainly completed through diffusion and convection processes;

[0062] There are certain loss mechanisms in the migration process, such as biodegradation, physical settlement or interception;

[0063] Soil properties (such as porosity, water content) and environmental conditions (such as water flow velocity) have important influence on the migration process.

[0064] The diffusion process is the spontaneous diffusion of microplastics from high concentration areas to low concentration areas due to concentration gradient; the migration process is the passive migration of microplastics with soil water flow, and the direction is consistent with the water flow; the degradation process is the decrease of the number of microplastics due to biodegradation, physical settlement, etc. Therefore, based on the above basic assumptions, the above processes can be accurately described by establishing a mathematical model, and the concentration change of microplastics at different soil depths and times can be predicted.

[0065] As can be seen from the function expression of the microplastic migration model, it is mainly divided into three parts. The first part is the diffusion term, which describes the migration of microplastics along the soil depth direction due to concentration difference; the second part is the convection term, which introduces the soil water flow velocity to describe the passive migration of microplastics with water flow; the third part is the attenuation term, which reflects the removal rate of microplastics due to degradation, settlement or interception, etc.

[0066] Here, the three processes of diffusion, convection and degradation are unified into a differential equation, which fully reflects the migration mechanism of microplastics in soil pore water. Both the spontaneous diffusion of microplastics due to concentration gradient and the passive migration of microplastics with soil water flow are considered, and the loss term of degradation or interception is introduced to truly represent the complex dynamics of pollutant transport, providing a scientific basis for subsequent generation of microplastic concentration input and ensuring that the correction factor is based on real and dynamic pollutant status.

[0067] For the equivalent diffusion coefficient of microplastics in soil, the logic for obtaining it is as follows:

[0068] Calculate the average radius of all microplastic particles that meet the imaging conditions (i.e., diameter greater than 100 microns);

[0069] Substitute the average radius into the Stokes-Einstein equation to calculate the free water diffusion coefficient of microplastics in pure water;

[0070] Based on the soil porosity and the preset diffusion path coefficient, the free water diffusion coefficient is corrected, and the product of the three is taken as the equivalent diffusion coefficient of microplastics in soil.

[0071] where the Stokes-Einstein equation is expressed as:

[0072] ;

[0073] where represents the free water diffusion coefficient of microplastics in pure water, represents the Boltzmann constant, which is approximately , represents the environmental temperature (Kelvin temperature), represents the dynamic viscosity of pure water, represents the average radius of microplastic particles that meet the imaging conditions (i.e., diameter greater than 100 microns).

[0074] The equivalent diffusion coefficient is expressed as: , where , respectively represent the preset diffusion path coefficient and the soil porosity. The diffusion path coefficient is used to reflect the restriction of soil medium structure on diffusion path, which is usually obtained by empirical formula or Tessier-Ackermann equation. While the diffusion distance can be calculated by the root mean square displacement formula: . Therefore, the equivalent diffusion coefficient can also be obtained by soil diffusion test, that is, injecting microplastic particles with fluorescent label into the known soil sample, and then measuring the diffusion distance at regular intervals to obtain the approximate value.

[0075] The degradation rate of microplastics in soil can be obtained by looking up typical degradation rates based on the type of microplastic, or by periodically measuring the change in microplastic mass over time using the soil diffusion test mentioned above.

[0076] By accurately acquiring diffusion and degradation parameters, the parameters in the microplastic migration model are made more reliable, improving the model's predictive performance and data interpretability. This ensures the accuracy of the basic data for subsequent calculations, avoids the reduction in accuracy caused by the amplification of model errors, and allows for dynamic adjustment of parameters based on different soil types and microplastic sources. It can be flexibly extended to various aquaculture environments and soil types, improving the applicability of the solution.

[0077] S2: Based on the microplastic migration model and the antibiotic inhibition kinetic model, a microplastic-antibiotic synergistic correction factor related to soil depth is generated.

[0078] The antibiotic inhibition kinetic model is constructed based on a first-order generation-decrease kinetic model to reflect the changing trend of antibiotic inhibition rate over time at different soil depths. Its functional expression is as follows:

[0079] ;

[0080] In the formula , They represent time. At that time, the soil depth was The antibiotic inhibition rate and antibiotic concentration at each location are dimensionless data ranging from 0 to 1. , These represent the inhibition generation rate constant and the inhibition decay rate constant, respectively, reflecting the inhibitory effect of antibiotics on microorganisms and the resistance of microorganisms to antibiotics. They can be combined into a single, comprehensive inhibition parameter. This simplifies the antibiotic inhibition kinetic model to:

[0081] ;

[0082] Furthermore, the overall suppression parameters are obtained by fitting the parameters obtained from actual measurements.

[0083] It is understandable that antibiotics in livestock and poultry manure have a certain toxic inhibitory effect on soil microorganisms, affecting the conversion of elements such as nitrogen, phosphorus, and potassium in manure by microorganisms, and thus also affecting the soil carrying capacity.

[0084] Microbial activity indicators include, but are not limited to, carbon dioxide release, enzyme activity, and microbial abundance. The logic for obtaining antibiotic inhibition rate is as follows:

[0085] Collect soil samples in non-polluted areas as a control group, and collect microbial activity indicators in non-polluted areas at the same time as the control group;

[0086] The difference between the microbial activity indicators of the non-polluted area and the polluted area is taken as the baseline, and the ratio between the microbial activity indicators of the non-polluted area and the polluted area is taken as the antibiotic inhibition rate.

[0087] The calculation formula of the antibiotic inhibition rate is:

[0088] ;

[0089] In the formula, , respectively represent the normalized value of the first microbial activity indicator at the soil depth of at time in the non-polluted area and the polluted area, respectively represent the index of the microbial activity indicator, represent the number of microbial activity indicators. The antibiotic inhibition rate ranges from 0 to 1, and the larger the value, the stronger the inhibition of antibiotics on microorganisms in the soil.

[0090] From the function expression set of the antibiotic inhibition kinetics model, it can be seen that it includes two parts. The first part reflects the generation of inhibition, meaning that the antibiotic concentration causes the microbial activity indicator to decrease, making the inhibition index deepen with the increase of antibiotic concentration and time. The second part reflects the attenuation of inhibition, meaning that the adaptation of microorganisms, degradation or conversion of antibiotics weakens the inhibition effect, making the inhibition index decay over time.

[0091] S3: Calculate the initial carrying capacity of the land using the NPK model, and use the microplastic-antibiotic synergistic correction factor to correct the initial carrying capacity to obtain the corrected carrying capacity related to soil depth. The NPK model is a method for calculating the carrying capacity of land in the prior art, and the specific calculation method can be obtained from "Guidelines for Calculating Carrying Capacity of Livestock and Poultry Manure Land". Here, no more details are given.

[0092] The logic for generating the microplastic-antibiotic synergistic correction factor related to soil depth is:

[0093] When the derivative of the microplastic concentration and the antibiotic inhibition rate with respect to time in the microplastic migration model and the antibiotic inhibition kinetics model is 0, it is considered that the land has reached a steady state, meaning that the obtained microplastic concentration and antibiotic inhibition rate represent the long-term average or steady state level, which is more suitable for developing stable and reliable management strategies.

[0094] ​The microplastic-antibiotic synergistic correction factor is generated by taking the microplastic concentration and the antibiotic inhibition rate when the land reaches a steady state as a benchmark, to reflect the synergistic effect of microplastics and antibiotics on the carrying capacity of the land, and its functional expression is:

[0095]

[0096] In the formula, represents the microplastic-antibiotic synergistic correction factor at a soil depth of , which is 1 in the absence of microplastic and antibiotic pollution, i.e., the soil carrying capacity is not affected by the two, and the smaller the value, the greater the impact of microplastics and antibiotics on the carrying capacity of the land, , respectively represent the microplastic concentration and the antibiotic inhibition rate at a soil depth of when the land reaches a steady state, , respectively represent the impact coefficients of microplastics and antibiotics, and respectively represent the linear negative impact of microplastics and antibiotics alone on the carrying capacity of the land, i.e., the reduction rate of the carrying capacity of the land caused by unit microplastic concentration and unit antibiotic concentration, represents the synergistic factor between microplastics and antibiotics, representing the interactive synergistic effect between the two, i.e., the reduction rate of the carrying capacity of the land caused by unit microplastic concentration and unit antibiotic concentration. When the value is positive, it is considered that the two partially offset, and when the value is negative, it is considered that the two synergistically enhance.

[0097] wherein , are both greater than 0, The positive and negative of the two are determined by the actual synergistic effect between microplastics and antibiotics. For the values of the three, corresponding typical value ranges can be obtained according to expert experience, or control experiments can be set up and fitted according to experimental data. Specifically, a microplastic-only impact group can be set up in the laboratory, different microplastic concentrations (such as 0, 10%, 20%, etc.) are set in the group, and the change rate of the carrying capacity of the land (calculated by the NPK model) under different concentrations is measured, so as to fit . Similarly, an antibiotic-only impact group can also be set up, different antibiotic concentrations are set in the group, and the change rate of the carrying capacity of the land (calculated by the NPK model) under different concentrations is measured, so as to fit . And for the synergistic factor , corresponding cross combinations (such as a 4*4 matrix of microplastic concentration and antibiotic concentration) can be set up, combined with , to obtain a fitting formula:

[0098] ​​

[0099] wherein represents the change rate of the initial bearing capacity, specifically the change amount of the initial bearing capacity to the initial bearing capacity .

[0100] The corrected bearing capacity is the product of the initial bearing capacity and the microplastic-antibiotic synergistic correction factor, that is: . wherein represents the corrected bearing capacity at the soil depth of , and represents the initial bearing capacity calculated using the NPK model.

[0101] It can be understood that the migration and biological effects of microplastics and antibiotics in soil are dynamic processes that change over time, involving diffusion, convection, degradation, sedimentation, microbial response, and other time-varying mechanisms. The time variable is a necessary parameter for describing the evolution of pollutant concentration and inhibition effect over time, which helps accurately capture the behavior and impact of pollutants at different stages. Differential equations can be established to reflect the dynamic changes of pollutant migration and inhibition effect, helping to understand short-term pulse input, event-driven changes, and the process of the system tending to steady state. However, since land bearing capacity calculation usually focuses on the average or steady-state bearing capacity at a longer time scale (such as annual or growth period), rather than the dynamic changes at an instant, when guiding management decisions, the parameters are usually used when the land is in a steady state to remove the time variable. This is to simplify the model, highlight long-term stable effects, and facilitate land bearing capacity calculation and management strategy development.

[0102] S4: Based on the optimal planting depth of the target crop, the corrected bearing capacity of the target crop at the optimal planting depth is obtained, and the corrected bearing capacity is compared with the preset recommended bearing capacity interval to generate a fecal pollution dosage control strategy based on the comparison result. The recommended bearing capacity interval can also be obtained from the table in the "Technical Guide for Calculating Land Bearing Capacity of Livestock and Poultry Manure".

[0103] The logic of the fecal pollution dosage control strategy is as follows:

[0104] When the corrected bearing capacity of the target crop at the optimal planting depth is greater than the upper limit of the recommended bearing capacity interval, it is considered that the land bearing capacity is strong, and the nutrient absorption and degradation function is good, and the fecal pollution dosage is increased to improve the land nutrients;

[0105] When the corrected bearing capacity of the target crop at the optimal planting depth is in the recommended bearing capacity interval, it is considered that the land bearing capacity is general, and the nutrient absorption and degradation function is moderate, and the fecal pollution dosage is kept unchanged;

[0106] ​When the corrected bearing capacity of the target crop at the optimal planting depth is less than the lower limit of the recommended bearing capacity interval, it is considered that the land bearing capacity is weak, the nutrient absorption and degradation function is poor, and the amount of manure should be reduced to avoid damage to the land.

[0107] Specifically, the increased and reduced amount of manure is determined by expert experience and meets the environmental protection requirements, and will not cause environmental pollution to the land, and is generally set between 10% and 20%.

[0108] In this step, by focusing on the optimal planting depth of the target crop, the initial bearing capacity is corrected using the microplastic-antibiotic synergistic correction factor, which not only reflects the dynamic influence of microplastics and antibiotics on soil function, but also directly evaluates the key soil layer for crop root growth and nutrient absorption, avoiding the uncertainty and error caused by the overall land bearing capacity calculated by the NPK model in traditional technology. Based on the comparison between the initial bearing capacity and the recommended bearing capacity interval, the corresponding control strategy is set, the theoretical model output is converted into specific fertilization decision, and the closed-loop process from pollutant dynamic simulation to land bearing capacity correction to on-site management is realized, thereby greatly promoting the efficient use of manure resources.

[0109] The above formulas are dimensionless values, and the formulas are obtained by software simulation of a large amount of data to obtain the most recent real situation, and the preset parameters in the formula are set by a person skilled in the art according to the actual situation.

[0110] The above embodiments can be realized wholly or partially by software, hardware, firmware or any combination thereof. When realized by software, the above embodiments can be realized wholly or partially in the form of a computer program product. Those skilled in the art can realize that the units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized by hardware or software methods depends on the specific application and design constraints of the technical solutions.

[0111] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, which can be located in one place or distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0112] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application.

Claims

1. A livestock and poultry manure land bearing capacity calculation method, characterized in that, The specific steps include: S1: Set sampling points in the pollution area and the non-pollution area respectively, collect soil quality parameters, microplastic concentration, antibiotic concentration and microbial activity indicators at different soil depths, and establish a microplastic migration model and an antibiotic inhibition kinetics model related to the depth; S2: Based on the microplastic migration model and the antibiotic inhibition kinetics model, generate a microplastic-antibiotic synergistic correction factor related to the soil depth, which is used to reflect the synergistic effect of microplastics and antibiotics on the land carrying capacity; The logic for generating the microplastic-antibiotic synergistic correction factor related to the soil depth is as follows: When the derivative of the microplastic concentration and the antibiotic inhibition rate in the microplastic migration model and the antibiotic inhibition kinetics model with respect to time is 0, it is considered that the land reaches a steady state; The microplastic-antibiotic synergistic correction factor is generated based on the microplastic concentration and the antibiotic inhibition rate when the land reaches a steady state, and its function expression is: wherein represents the microplastic-antibiotic synergistic correction factor at a soil depth of , represents the microplastic concentration and the antibiotic inhibition rate at a soil depth of , , represents the influence coefficient of microplastics, antibiotics, respectively, represents the synergistic factor between microplastics and antibiotics;​ S3: Calculate the initial carrying capacity of the land using the NPK model, and correct the initial carrying capacity using the microplastic-antibiotic synergistic correction factor to obtain a corrected carrying capacity related to the soil depth; S4: Based on the optimal planting depth of the target crop, obtain the corrected carrying capacity of the target crop at the optimal planting depth, and compare the corrected carrying capacity with a preset recommended carrying capacity interval to generate a fecal pollution dosage control strategy based on the comparison result.

2. The method according to claim 1, wherein: The soil quality parameters include but are not limited to soil pore water content and soil water flow velocity; The logic for collecting the microplastic concentration is as follows: Separate the microplastic particles from the soil after flotation, and use a fluorescence microscope to image microplastic particles with a diameter greater than 100 microns; Collect the characteristic spectrum of the microplastic particles by near-infrared spectroscopy, and compare it with the standard spectrum library to classify and count the types and quantities of the microplastic particles; Based on the types, quantities and volumes of the microplastic particles, calculate the microplastic concentration, which is defined as the ratio between the total mass of all microplastic particles and the mass of the soil.

3. The method according to claim 2, wherein the method is characterized in that: The microplastic migration model is constructed based on the first-order convection-diffusion equation, which is used to reflect the trend of the microplastic concentration changing with time at different soil depths, and its function expression is: wherein denotes the concentration of microplastics at a soil depth of at time denote time and soil depth, respectively denote the effective diffusion coefficient of microplastics in soil, the soil water flow velocity, the degradation rate, respectively.​​​​ 4. The method according to claim 3, characterized in that: The logic for obtaining the equivalent diffusion coefficient is as follows: Calculate the average radius of all microplastic particles that meet the imaging conditions; Substitute the average radius into the Stokes-Einstein equation to calculate the free water diffusion coefficient of the microplastic in pure water; Based on the soil pore water content and a preset diffusion path coefficient, correct the free water diffusion coefficient, and take the product of the three as the equivalent diffusion coefficient of the microplastic in the soil.

5. The method according to claim 3, characterized in that: The microbial activity indicators include but are not limited to carbon dioxide release, enzyme activity and microbial abundance, which are used to calculate the antibiotic inhibition rate to reflect the inhibition of antibiotics on the microorganisms in the soil; The antibiotic inhibition kinetics model is constructed based on the first-order generation-decay kinetics model to reflect the trend of the antibiotic inhibition rate changing with time at different soil depths, and its function expression is: wherein , respectively represent the antibiotic inhibition rate and the antibiotic concentration at the soil depth of , at the time of , respectively represent the inhibition generation rate constant and the inhibition decay rate constant.

6. The method according to claim 5, wherein: The logic for obtaining the antibiotic inhibition rate is as follows: Take the soil samples in the non-pollution area as the control group, and collect the microbial activity indicators in the non-pollution area at the same time as the microbial activity indicators in the pollution area are collected; The difference between the microbial activity index of the non-polluted area and the polluted area is taken as the antibiotic inhibition rate.

7. The method according to claim 1, wherein the method is characterized in that: The modified bearing capacity is the product of the initial bearing capacity and the microplastic-antibiotic synergistic correction factor.

8. The method according to claim 1, characterized in that: The logic of the manure dosage regulation strategy is as follows: When the modified bearing capacity of the target crop at the optimal planting depth is greater than the upper limit of the recommended bearing capacity interval, it is considered that the land bearing capacity is strong, the nutrient absorption and degradation function is good, and the manure dosage is increased to improve the land nutrient; When the modified bearing capacity of the target crop at the optimal planting depth is in the recommended bearing capacity interval, it is considered that the land bearing capacity is general, the nutrient absorption and degradation function is moderate, and the manure dosage is kept unchanged; When the modified bearing capacity of the target crop at the optimal planting depth is less than the lower limit of the recommended bearing capacity interval, it is considered that the land bearing capacity is weak, the nutrient absorption and degradation function is poor, and the manure dosage is reduced to avoid damage to the land.

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