A farmland system phosphorus balance accounting method and system

Abstract

The present application relates to the technical field of agricultural ecological accounting, in particular to a farmland system phosphorus balance accounting method and system, wherein the farmland system phosphorus balance accounting method comprises the following steps: S1: obtaining farmland system phosphorus input and phosphorus output data; S2: based on the farmland system phosphorus input and phosphorus output data, establishing a phosphorus input, phosphorus output and phosphorus balance accounting database; S3: based on the accounting database, evaluating the farmland system phosphorus balance. In view of the problems of weak phosphorus management of farmland systems in many regions and insufficient research on utilization efficiency, the method and system can estimate the phosphorus balance of farmland systems in different regions, different years and different crop types, which has important significance for scientific management of farmland system phosphorus input, improvement of phosphorus fertilizer utilization efficiency and control of agricultural non-point source pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural ecological accounting, and in particular to a method and system for calculating phosphorus balance in a farmland system. Background Art

[0002] Phosphorus, an essential nutrient for plant growth, plays a decisive role in crop yield and quality. In farmland phosphorus management, rational regulation of phosphorus input is crucial for ensuring stable food production and mitigating the negative impacts of phosphorus loss on the ecological environment. Most studies evaluating farmland phosphorus balances focus solely on phosphorus inputs from chemical fertilizers and some organic fertilizers, neglecting other important sources of phosphorus, such as atmospheric deposition, rock weathering, and seed phosphorus input. Furthermore, quantification of phosphorus output pathways, such as soil erosion, runoff, and seepage, lacks a systematic and comprehensive approach. Furthermore, existing accounting models are mostly static, failing to fully account for regional variations, such as the impact of soil type, climate, and cropping structure on the phosphorus cycle. This results in significant deviations from actual conditions and fails to provide reliable guidance for precision agriculture management. This not only leads to overapplication of phosphorus fertilizers, which in turn causes a range of environmental problems, such as soil phosphorus accumulation and water eutrophication, but also increases agricultural production costs. Therefore, the development of an accurate and comprehensive method and system for calculating phosphorus balances in farmland systems is urgent.

[0003] Chinese invention patent publication number CN117371854A discloses a carbon and nitrogen footprint assessment method and system for agricultural crop production. This method focuses on carbon and nitrogen in agricultural crop production, comprehensively considering the source and sink processes of carbon and nitrogen, including carbon and nitrogen emissions and absorption from multiple aspects such as energy consumption, livestock input, and material input. However, those skilled in the art are aware that the life cycle framework of the carbon and nitrogen footprint cannot be directly applied to phosphorus balance accounting, as the environmental risks of phosphorus (such as eutrophication) and the greenhouse gas effect operate on completely different mechanisms, requiring the design of a separate material flow model.

[0004] Currently, research on the precise calculation and scientific management of phosphorus balance in farmland systems is relatively lagging, and effective accounting methods and systems are urgently needed to support the sustainable development of agriculture. Therefore, in-depth research on the phosphorus balance in farmland systems is of great practical significance for the scientific and rational management of phosphorus fertilizer use in the crop industry, while ensuring and increasing grain yields, improving the efficiency of phosphorus fertilizer use, reducing phosphorus fertilizer waste and excessive phosphorus accumulation in the soil. Summary of the Invention

[0005] In response to the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method and system for calculating the phosphorus balance of a farmland system. By applying material flow analysis and input-output methods, a phosphorus balance accounting model for a farmland system is constructed to comprehensively and accurately quantify the phosphorus input (covering chemical fertilizers, agricultural fertilizers, seeds, atmospheric deposition, rock weathering, wastewater irrigation, straw return to the field, etc.) and phosphorus output (including agricultural products, straw harvesting, soil erosion, runoff, leakage, etc.) of the farmland system. Then, a balance model is established to deeply analyze the regional phosphorus surplus / deficit situation and phosphorus utilization efficiency, providing a scientific and reliable basis for optimizing phosphorus fertilizer application strategies and reducing environmental risks.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0007] In a first aspect, a method for calculating phosphorus balance in a farmland system is provided, comprising the following steps:

[0008] S1: Obtain the phosphorus input and output data of the farmland system;

[0009] S2: Based on the phosphorus input and output data of the farmland system, a database for phosphorus input, output and phosphorus balance accounting is established;

[0010] S3: Evaluate phosphorus balance in cropland systems based on accounting databases;

[0011] Among them, phosphorus input includes phosphorus input from chemical fertilizers, phosphorus input from agricultural fertilizers, phosphorus input from seeds, phosphorus input from straw return to fields, phosphorus input from urban wastewater irrigation, phosphorus input from atmospheric phosphorus deposition and phosphorus input from rock weathering; phosphorus output includes phosphorus output from agricultural product consumption, phosphorus output from straw harvesting, phosphorus output from soil erosion, phosphorus output from soil runoff, and phosphorus output from soil leakage; phosphorus balance is phosphorus input minus phosphorus output.

[0012] Furthermore, it also includes the calculation of phosphorus utilization efficiency, which is the ratio between the phosphorus content of agricultural products and the phosphorus input into farmland.

[0013] Furthermore, the phosphorus input to the farmland system was calculated according to the following formula:

[0014]

[0015] Where, is the phosphorus input, unit is t P; is the fertilizer phosphorus input, unit is t P; is the phosphorus input of agricultural fertilizer, unit is t P; is the seed phosphorus input, unit is t P; is the phosphorus input for urban wastewater irrigation, in t P; is the atmospheric phosphorus deposition input, unit is t P; is the rock weathering phosphorus input, unit is t P; is the phosphorus input from returning straw to the field, unit is tP.

[0016] Furthermore, the calculation formula for each phosphorus input is as follows:

[0017] (1) Phosphorus input of chemical fertilizers, including pure phosphate fertilizer input and compound fertilizer phosphate input, is as follows:

[0018] (2)

[0019] Where, is the fertilizer phosphorus input, unit is t P; is the amount of phosphate fertilizer input, unit is t ; 0.3827 is phosphorus proportion; is the phosphorus input of compound fertilizer, unit is t P; 0.15 is the phosphorus content in compound fertilizer, mainly based on N+ + The mass concentration of phosphorus is required to be 25 ~ 40%, usually the phosphorus content is 10 ~ 20%, and the average value is 15%;

[0020] (2) The amount of phosphorus input into agricultural fertilizers is calculated based on the amount of animal manure returned to the fields. The calculation formula is as follows:

[0021]

[0022] Where, is the amount of phosphorus input into agricultural fertilizers, in t P; For the i Number of animals of the species, in pieces or units; For each year i Number of times the species is raised, dimensionless; For the i The amount of feces produced by a species of animal in a year, in tons; is the rate of manure return to the field, dimensionless; is the phosphorus content in feces, dimensionless;

[0023] (3) The amount of atmospheric deposition phosphorus input is calculated based on the deposition per unit area. The calculation formula is as follows:

[0024]

[0025] Where, is the atmospheric deposition phosphorus input, unit is t P, is the annual atmospheric deposition phosphorus input per unit area, in kg P / ha; A is the planted area, in ha;

[0026] (4) The input of phosphorus from rock weathering is calculated based on the amount of rock weathering per unit area. The calculation formula is as follows:

[0027]

[0028] Where, is the phosphorus input from rock weathering, unit is t P; is the rock weathering phosphorus input per unit area, in kg P / ha; A is the planted area, in ha;

[0029] (5) The amount of phosphorus input from urban wastewater is calculated based on the agricultural irrigation rate of urban wastewater. The calculation formula is as follows:

[0030]

[0031] Where, is the phosphorus input to urban wastewater, unit is t P; is the annual amount of urban wastewater generated, in tons; is the phosphorus content in municipal wastewater, dimensionless; is the urban wastewater treatment rate, dimensionless; The phosphorus treatment rate of urban wastewater is the proportion of phosphorus in wastewater that is recycled and reused by sewage treatment plants, etc., dimensionless; is the urban wastewater agricultural irrigation rate, dimensionless;

[0032] (6) Seed phosphorus input is calculated based on the seed input. The calculation formula is as follows:

[0033]

[0034] Where, is the amount of phosphorus input to seeds, unit is t P; is the amount of crop seed input for category i, in kg / ha; is the planting area of ​​crop type i, in ha; is the phosphorus content in each grain agricultural product;

[0035] (7) The phosphorus input from returning straw to the field is calculated based on the amount of straw returned to the field. The calculation formula is as follows:

[0036]

[0037] Where, is the phosphorus input of straw returned to the field, unit is t P; is the yield of type i crops, in t; is the grass-to-grain ratio of crop type i, dimensionless; is the phosphorus content in each crop straw, dimensionless; is the rate of returning crop straw to the field, dimensionless.

[0038] Furthermore, the phosphorus output of the farmland system was calculated according to the following formula:

[0039]

[0040] Where, is the phosphorus output, unit is t P; is the phosphorus output consumed by agricultural products, in tP; Phosphorus output from straw harvest, in t P; is the soil erosion phosphorus output, in t P; is the soil runoff phosphorus output, in t P; is the soil leakage phosphorus output, unit is tP.

[0041] Furthermore, the calculation formula for each phosphorus output is as follows:

[0042] (1) The output of phosphorus consumed by agricultural products is calculated based on the output of agricultural products. The calculation formula is as follows:

[0043]

[0044] Where, is the output of phosphorus consumed by agricultural products, unit is t P; is the yield of type i crops, in t; is the phosphorus content in each grain agricultural product, dimensionless;

[0045] (2) The phosphorus output from straw harvest is calculated based on the straw harvest amount. The calculation formula is as follows:

[0046]

[0047] Where, is the phosphorus output of straw harvest, unit is t P; is the yield of type i crops, in t; is the grass-to-grain ratio of crop type i, dimensionless; is the phosphorus content in each crop straw, dimensionless; is the rate of returning crop straw to the field, dimensionless;

[0048] (3) Soil loss phosphorus output, including soil erosion phosphorus output, seepage phosphorus output and runoff phosphorus output, is calculated as follows:

[0049]

[0050]

[0051] Where, is the soil erosion phosphorus output, unit is t P; is the soil runoff phosphorus output, unit is t P; is the output of soil leakage phosphorus, unit is t P; is the output of phosphorus from soil erosion per unit area, in kg P / ha; soil runoff phosphorus output can be divided into paddy crops ( ) and other crops ( ) Phosphorus output, unit is kg P / ha; soil leakage phosphorus output can also be divided into paddy field crop infiltration phosphorus output ( ) and other crop phosphorus exports ( ), unit is kg P / ha; A is the cultivated area of ​​farmland, is the planting area of ​​each paddy field crop, is the planting area of ​​other crops, in ha.

[0052] In a second aspect, a system for calculating phosphorus balance in a farmland system is provided, and the system is used to implement the calculation of any of the above methods, including:

[0053] The phosphorus balance database establishment module is used to establish a database for phosphorus balance accounting in the farmland system, and includes the following sub-databases;

[0054] Phosphorus input calculation module, used to calculate the phosphorus input amount of the farmland system;

[0055] Phosphorus output calculation module, used to calculate the phosphorus output of the farmland system;

[0056] Phosphorus balance calculation module, used to calculate the phosphorus surplus / deficit of the farmland system;

[0057] Phosphorus use efficiency module, used to calculate the phosphorus use efficiency of the farmland system;

[0058] The phosphorus input calculation module includes a natural process phosphorus input calculation submodule and a production material input calculation submodule, which are used to calculate the natural process phosphorus input and the production material phosphorus input respectively; the phosphorus output calculation module includes a crop absorption phosphorus output calculation submodule and a soil loss phosphorus output calculation submodule;

[0059] The submodule for calculating phosphorus inputs from natural processes includes phosphorus inputs from atmospheric deposition and rock weathering; the submodule for calculating inputs from production materials includes phosphorus inputs from chemical fertilizers, agricultural fertilizers, seeds, straw return to fields, and urban wastewater irrigation; the submodule for calculating phosphorus outputs absorbed by crops includes phosphorus outputs absorbed by agricultural products and straw harvesting; the submodule for calculating phosphorus outputs from soil loss includes phosphorus outputs from soil erosion, soil runoff, and soil infiltration.

[0060] In a third aspect, an electronic device is provided, comprising a processor and a memory, wherein the memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory to implement any of the steps of the above-mentioned farmland system phosphorus balance accounting method.

[0061] In a fourth aspect, a computer-readable storage medium storing computer instructions is provided, wherein the computer instructions are used to enable a computer to execute the steps of any one of the above-mentioned methods for calculating phosphorus balance in a farmland system.

[0062] The beneficial effects of the present invention are:

[0063] 1. By accurately assessing phosphorus balance and clarifying the phosphorus demand characteristics of different crops, the present invention can provide agricultural producers with scientific recommendations for the application of phosphorus fertilizers, avoid excessive or insufficient input of phosphorus fertilizers, improve the efficiency of phosphorus fertilizer utilization, reduce production costs, and at the same time reduce the harm of phosphorus pollution to the environment.

[0064] 2. The method of the present invention can be used to conduct research at different unit scales, reflecting the differences in phosphorus balance in farmland systems in different regions, analyzing the proportion of each component of phosphorus input, and determining the main phosphorus source; analyzing the various components of phosphorus output, and evaluating the severity of problems such as soil phosphorus loss, providing strong data support for formulating agricultural development policies suitable for the region, optimizing planting structures, and strengthening environmental protection.

[0065] 3. The calculation method of the present invention can be used to understand the phosphorus input, output, balance and corresponding phosphorus utilization efficiency of a region at different scales, such as the national, regional, provincial, city and county levels, and to clarify the contribution of phosphorus to the farmland system in the region, thus providing a scientific basis for regional agricultural planning and scientific management. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is the framework diagram of the phosphorus balance accounting system in the farmland system;

[0067] Figure 2 This is the flow chart for phosphorus balance calculation in farmland system. DETAILED DESCRIPTION

[0068] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0069] Example 1:

[0070] A method for calculating phosphorus balance in a farmland system comprises the following steps:

[0071] S1: Obtain the phosphorus input and output data of the farmland system;

[0072] S2: Based on the phosphorus input and output data of the farmland system, a database for phosphorus input, output and phosphorus balance accounting is established;

[0073] S3: Evaluate phosphorus balance in cropland systems based on accounting databases.

[0074] The present invention systematically studies the effective correlation between the four parts of phosphorus input, phosphorus output, phosphorus balance and phosphorus utilization efficiency related to the phosphorus balance accounting of the farmland system. In the existing technology, the effective correlation research of these four parts has not been fully involved, or only a simple study of phosphorus balance is conducted on the planting situation of a single crop in a certain area, or there is no systematic study on the phosphorus cycle pathways under different crop planting patterns in different regions, or only a one-sided accounting is conducted on a certain part (such as phosphorus input or phosphorus output).

[0075] Specifically, the phosphorus input to the farmland system should be calculated first: a database covering various sources of phosphorus input should be established, including fertilizer phosphorus input, agricultural fertilizer phosphorus input, seed phosphorus input, urban wastewater irrigation phosphorus input, atmospheric deposition phosphorus input, rock weathering phosphorus input, and straw return phosphorus input. This database should include parameters such as fertilizer use, crop seed use, urban wastewater generation and treatment rate, planted area, atmospheric deposition, rock weathering rate, and straw return rate.

[0076] Phosphorus balance accounting in farmland systems mainly includes phosphorus input accounting, phosphorus output accounting, phosphorus balance accounting and phosphorus utilization efficiency accounting.

[0077] Phosphorus input to the farmland system is calculated according to the following formula:

[0078]

[0079] Where, is the phosphorus input, unit is t P; is the fertilizer phosphorus input, unit is t P; is the phosphorus input of agricultural fertilizer, unit is t P; is the seed phosphorus input, unit is t P; is the phosphorus input for urban wastewater irrigation, in t P; is the atmospheric phosphorus deposition input, unit is t P; is the rock weathering phosphorus input, unit is t P; is the phosphorus input from returning straw to the field, unit is tP.

[0080] Furthermore, the calculation formula for each phosphorus input is as follows:

[0081] (1) Phosphorus input of chemical fertilizers, including pure phosphate fertilizer input and compound fertilizer phosphate input, is as follows:

[0082] (2)

[0083] Where, is the fertilizer phosphorus input, unit is t P; is the amount of phosphate fertilizer input, unit is t ; 0.3827 is phosphorus proportion; is the phosphorus input of compound fertilizer, unit is t P; 0.15 is the phosphorus content in compound fertilizer, mainly based on N+ + The mass concentration of phosphorus is required to be 25 ~ 40%, usually the phosphorus content is 10 ~ 20%, and the average value is 15%;

[0084] (2) The amount of phosphorus input into agricultural fertilizers is calculated based on the amount of animal manure returned to the fields. The calculation formula is as follows:

[0085]

[0086] Where, is the amount of phosphorus input into agricultural fertilizers, in t P; For the i Number of animals of the species, in pieces or units; For each year i Number of times the species is raised, dimensionless; For the i The amount of feces produced by a species of animal in a year, in tons; is the rate of manure return to the field, dimensionless; is the phosphorus content in feces, dimensionless;

[0087] (3) The amount of atmospheric deposition phosphorus input is calculated based on the deposition per unit area. The calculation formula is as follows:

[0088]

[0089] Where, is the atmospheric deposition phosphorus input, unit is t P, is the annual atmospheric deposition phosphorus input per unit area, in kg P / ha; A is the planted area, in ha;

[0090] (4) The input of phosphorus from rock weathering is calculated based on the amount of rock weathering per unit area. The calculation formula is as follows:

[0091]

[0092] Where, is the phosphorus input to rock weathering, in t P; is the rock weathering phosphorus input per unit area, in kg P / ha; A is the planted area, in ha;

[0093] (5) The amount of phosphorus input from urban wastewater is calculated based on the agricultural irrigation rate of urban wastewater. The calculation formula is as follows:

[0094]

[0095] Where, is the phosphorus input to urban wastewater, unit is t P; is the annual amount of urban wastewater generated, in tons; is the phosphorus content in municipal wastewater, dimensionless; is the urban wastewater treatment rate, dimensionless; The phosphorus treatment rate of urban wastewater is the proportion of phosphorus in wastewater that is recycled and reused by sewage treatment plants, etc., dimensionless; is the urban wastewater agricultural irrigation rate, dimensionless;

[0096] (6) Seed phosphorus input is calculated based on the seed input. The calculation formula is as follows:

[0097]

[0098] Where, is the amount of phosphorus input to seeds, unit is t P; is the amount of crop seed input for category i, in kg / ha; is the planting area of ​​crop type i, in ha; is the phosphorus content in each grain agricultural product;

[0099] (7) The phosphorus input from returning straw to the field is calculated based on the amount of straw returned to the field. The calculation formula is as follows:

[0100]

[0101] Where, is the phosphorus input of straw returned to the field, unit is t P; is the yield of type i crops, in t; is the grass-to-grain ratio of crop type i, dimensionless; is the phosphorus content in each crop straw, dimensionless; is the rate of returning crop straw to the field, dimensionless.

[0102] Furthermore, the phosphorus output of the farmland system was calculated according to the following formula:

[0103]

[0104] Where, is the phosphorus output, unit is t P; is the phosphorus output consumed by agricultural products, in tP; Phosphorus output from straw harvest, in t P; is the soil erosion phosphorus output, in t P; is the soil runoff phosphorus output, in t P; is the soil leakage phosphorus output, unit is tP.

[0105] Furthermore, the calculation formula for each phosphorus output is as follows:

[0106] (1) The output of phosphorus consumed by agricultural products is calculated based on the output of agricultural products. The calculation formula is as follows:

[0107]

[0108] Where, is the output of phosphorus consumed by agricultural products, unit is t P; is the yield of type i crops, in t; is the phosphorus content in each grain agricultural product, dimensionless;

[0109] (2) The phosphorus output from straw harvest is calculated based on the straw harvest amount. The calculation formula is as follows:

[0110]

[0111] Where, is the phosphorus output of straw harvest, unit is t P; is the yield of type i crops, in t; is the grass-to-grain ratio of crop type i, dimensionless; is the phosphorus content in each crop straw, dimensionless; is the rate of returning crop straw to the field, dimensionless;

[0112] (3) Soil loss phosphorus output, including soil erosion phosphorus output, seepage phosphorus output and runoff phosphorus output, is calculated as follows:

[0113]

[0114]

[0115]

[0116] Where, is the soil erosion phosphorus output, unit is t P; is the soil runoff phosphorus output, unit is t P; is the output of soil leakage phosphorus, unit is t P; is the output of phosphorus from soil erosion per unit area, in kg P / ha; soil runoff phosphorus output can be divided into paddy crops ( ) and other crops ( ) Phosphorus output, unit is kg P / ha; soil leakage phosphorus output can also be divided into paddy field crop infiltration phosphorus output ( ) and other crop phosphorus exports ( ), unit is kg P / ha; A is the cultivated area of ​​farmland, is the planting area of ​​each paddy field crop, is the planting area of ​​other crops, in ha.

[0117] Phosphorus balance is calculated as phosphorus input minus phosphorus output. The specific formula is:

[0118]

[0119] Where, It is the phosphorus balance or phosphorus surplus / phosphorus deficit of the farmland system, and its unit is tP.

[0120] Phosphorus utilization efficiency is the ratio between the phosphorus content of agricultural products and the phosphorus input to farmland. The specific formula is:

[0121]

[0122] Where E is the phosphorus use efficiency of the farmland system and is dimensionless.

[0123] In the present invention, the construction of the farmland system phosphorus balance accounting system requires the systematic integration of four core modules: phosphorus input, phosphorus output, phosphorus balance and phosphorus utilization efficiency analysis. Among them:

[0124] Phosphorus input accounting accurately quantifies natural and anthropogenic sources of phosphorus input by integrating seven sources (Formulas 2-8): chemical fertilizers, agricultural fertilizers, seeds, atmospheric deposition, rock weathering, municipal wastewater irrigation, and straw return to fields. Existing technologies often focus on chemical and organic fertilizers, ignoring the contributions of atmospheric deposition, rock weathering, seed inputs, and, in some areas, municipal wastewater irrigation. Furthermore, agricultural fertilizer accounting does not differentiate between livestock and poultry species, resulting in significant errors in total regional phosphorus inputs.

[0125] Phosphorus output accounting covers five pathways: agricultural harvest, straw removal, soil erosion, soil runoff, and soil seepage (Equations 10-14), modeled incorporating crop type and terrain differences. Phosphorus balance (Equation 15) provides real-time information on regional phosphorus surpluses and deficits. Existing technologies often rely on static analysis and fail to track the long-term impacts of crop structure adjustments (e.g., switching from corn to soybeans) or changes in management practices (e.g., increasing straw return from 60% to 80%) on phosphorus cycling, resulting in delayed policy development.

[0126] Phosphorus use efficiency (PUE) for farmland systems is calculated based on Equation 16 for different crops. This clarifies the extent of phosphorus utilization under different crops and cropping patterns, and helps improve PUE by addressing the varying P requirements of different crop types at different growth stages. Traditional studies have only compared efficiency values ​​without further quantifying the impact of climate conditions or agricultural practices, making it difficult to support accurate decision-making.

[0127] Furthermore, phosphorus input coefficients, loss pathways, and utilization efficiency vary significantly across regions due to differences in soil type (e.g., black soil vs. red soil), cropping structure (e.g., proportion of paddy fields), and management practices (e.g., straw return rate). For example, straw return contributes 21% of phosphorus input in Northeast China, while rock weathering contributes a higher percentage in the hilly southern regions. This invention, through its phosphorus balance accounting model and parameter library, provides a scientific paradigm for controlling agricultural non-point source pollution and reducing and increasing the efficiency of phosphorus fertilizers.

[0128] In addition, farmland systems in different regions have different phosphorus input-output coefficients, phosphorus balance states, and phosphorus utilization efficiencies due to differences in soil types, climatic conditions, planting structures, and agricultural management methods. These differences need to be fully considered during accounting and analysis.

[0129] Example 2:

[0130] Example 2 is a parallel example of Example 1, and mainly describes the structure and function of the phosphorus balance calculation system of the farmland system:

[0131] The phosphorus balance database establishment module is used to establish a database for phosphorus balance accounting in the farmland system, and includes the following sub-databases;

[0132] Phosphorus input calculation module, used to calculate the phosphorus input amount of the farmland system;

[0133] Phosphorus output calculation module, used to calculate the phosphorus output of the farmland system;

[0134] Phosphorus balance calculation module, used to calculate the phosphorus surplus / deficit of the farmland system;

[0135] Phosphorus use efficiency module, used to calculate the phosphorus use efficiency of the farmland system;

[0136] The phosphorus input calculation module includes a natural process phosphorus input calculation submodule and a production material input calculation submodule, which are used to calculate the natural process phosphorus input and the production material phosphorus input respectively; the phosphorus output calculation module includes a crop absorption phosphorus output calculation submodule and a soil loss phosphorus output calculation submodule;

[0137] The submodule for calculating phosphorus inputs from natural processes includes phosphorus inputs from atmospheric deposition and rock weathering; the submodule for calculating inputs from production materials includes phosphorus inputs from chemical fertilizers, agricultural fertilizers, seeds, straw return to fields, and urban wastewater irrigation; the submodule for calculating phosphorus outputs absorbed by crops includes phosphorus outputs absorbed by agricultural products and straw harvesting; the submodule for calculating phosphorus outputs from soil loss includes phosphorus outputs from soil erosion, soil runoff, and soil infiltration.

[0138] Example 3:

[0139] Example 3 is a further application of Example 1, and specifically describes the learning content of the electronic device: including a memory, a processor, and a computer program stored in the memory and running on the processor, and the steps of the method for calculating the phosphorus balance of the farmland system are implemented when the processor executes the computer program.

[0140] Example 4:

[0141] Example 4 is an analysis of the actual effects of the technical solutions described in any one of Examples 1-3.

[0142] Taking the farmland system in Northeast China in 2020 as an example, the database of phosphorus export coefficients of different types of grain agricultural products and straw is shown in Table 1.

[0143] Table 1 Database of phosphorus content in grain agricultural products and straw

[0144]

[0145] In Table 1, the corresponding grain agricultural products research objects are rice, wheat, corn, sorghum, millet, potatoes, soybeans, vegetables and oil crops; and the straw return utilization ratio is 0.172 in Liaoning Province, 0.173 in Jilin Province, and 0.229 in Heilongjiang Province. These data are obtained through field surveys and data collection on a large number of farmland samples in Northeast China, and combined with comprehensive analysis of relevant agricultural statistical data.

[0146] Based on the data in Table 1, using formulas (7) and (8), we can calculate that the seed phosphorus input in Northeast China is 2.38 kt P and the straw phosphorus input is 136.22 kt P. In the calculation process, for formula (7), i Amount of crop seed input The actual sowing amount of various crop seeds in Northeast China is counted, and then combined with the planting area The weighted average calculation is performed; the formula (8) (i) The yield of type I crops is based on the yield statistics of local agricultural departments, combined with the grass-to-grain ratio. , straw phosphorus content and straw return rate After precise calculation, the conversion coefficients corresponding to other phosphorus inputs are shown in Tables 2 and 3.

[0147] Table 2 Phosphorus input coefficient of agricultural fertilizers

[0148]

[0149] Phosphorus inputs from chemical fertilizers in farmland systems include both phosphate fertilizers and compound fertilizers (Equation 2). Phosphorus inputs from chemical fertilizers account for 71.8%, which translates to 895.19 kt P according to Equation 2. Agricultural fertilizers account for 3.9%, which translates to 49.07 kt P according to Equation 2.

[0150] Table 3 Correlation coefficients of other phosphorus inputs

[0151]

[0152] The atmospheric deposition coefficient of 1.5 kgP / ha is based on a comprehensive analysis of dry and wet atmospheric phosphorus deposition in Northeast China based on long-term atmospheric environmental monitoring data. The rock weathering coefficient of 0.525 kgP / ha was determined by analyzing rock samples from different geological conditions in Northeast China, combined with research on regional rock weathering rates. The urban wastewater correlation coefficient was calculated based on operational data from urban sewage treatment plants in Northeast China and the actual use of urban wastewater in agricultural irrigation. The soil erosion, runoff, and seepage coefficients were determined by long-term monitoring of phosphorus loss at monitoring points in farmland across Northeast China with varying terrain and soil types.

[0153] According to Tables 2 and 3, it can be calculated that the phosphorus input from atmospheric deposition is 36.97 kt P (calculated according to Formula 4), the phosphorus input from rock weathering is 12.95 kt P (calculated according to Formula 5), ​​and the phosphorus input from urban wastewater is 16.18 kt P (calculated according to Formula 6).

[0154] Phosphorus output includes crop consumption through agricultural product seeds and straw harvesting, which are calculated as 316.86 kt P and 279.46 kt P, respectively, using Equations 10 and 11. Furthermore, phosphorus output also includes soil activities: 6.29 kt P is derived from soil erosion, according to Equation 12; 7.51 kt P is derived from soil runoff, according to Equation 13; and 72.7 kt P is derived from soil seepage, according to Equation 14.

[0155] According to the above calculation results, we can further obtain:

[0156] Total phosphorus input, comprising the sum of fertilizer input, agricultural fertilizer input, seed input, atmospheric deposition, rock weathering input, straw incorporation, and municipal wastewater input, reached 1247.2 kt P. Fertilizer phosphorus input accounted for the largest share, at 71.8%, while straw incorporation also contributed significantly, accounting for 10.9%. This high proportion of fertilizer phosphorus reflects the reliance of agricultural production in Northeast China on fertilizers. The significant contribution of straw incorporation suggests that straw incorporation has, to a certain extent, replenished soil phosphorus in the region.

[0157] Total phosphorus output was 679.95 kt P, primarily concentrated in agricultural products (46.6%) and straw (41.1%). Soil seepage accounted for 84.05% of total phosphorus loss. This indicates that agricultural product harvesting and straw removal are the primary pathways of phosphorus output, while soil seepage is a significant source of phosphorus loss and warrants attention. This may be related to local soil texture, precipitation characteristics, and farmland drainage systems.

[0158] The phosphorus balance is 567.25 kt P (according to Equation 15). This suggests a phosphorus surplus in the Northeast China farmland system. Long-term phosphorus surpluses may lead to soil phosphorus accumulation, increasing environmental risks and necessitating rational adjustments to phosphorus fertilizer application strategies.

[0159] Formula (16) shows that the average phosphorus use efficiency of each crop in the farmland system is 0.26. The phosphorus use efficiency of different crops is shown in Table 4.

[0160] Table 4 Phosphorus utilization of farmland for different crops in Northeast China in 2020

[0161]

[0162] Rice's high phosphorus use efficiency may be due to its efficient phosphorus absorption and conversion mechanisms during growth, or it may be related to local rice cultivation management practices, such as appropriate irrigation and fertilization timing. Crops like sorghum, on the other hand, have lower phosphorus use efficiency, perhaps due to their biological characteristics, limited phosphorus absorption and utilization capacity, or inappropriate phosphorus fertilizer application during cultivation. Comparing the phosphorus use efficiency of different crops can provide a basis for targeted adjustments to phosphorus fertilizer application plans.

[0163] Example 5:

[0164] Example 5 is an analysis of the actual effects of the technical solutions described in any one of Examples 1-3.

[0165] A similar method was used to calculate the phosphorus balance of China's farmland system. The basic data was based on the Chinese farmland system in 2011. The phosphorus export coefficients of grain agricultural products and straw of different types of crops are shown in the following table:

[0166] Table 5 Phosphorus export coefficients of crops

[0167]

[0168] Table 6 Phosphorus input coefficient of agricultural fertilizer

[0169] Table 7 Correlation coefficients of other phosphorus inputs

[0170]

[0171] According to Table 5, Table 6 and Table 7, we can deduce:

[0172] In 2011, total phosphorus input to farmland in China was 7147.39 ktP / a (Equation 1). Of this, fertilizer input accounted for 5041.65 ktP / a (Equation 2), accounting for 70.54% and making it the primary source of phosphorus input. Agricultural fertilizer input accounted for 1655.56 ktP / a (Equation 3), accounting for 23.16%; atmospheric deposition input accounted for 20.25 ktP / a (Equation 4), accounting for 0.28%; rock weathering input accounted for 7.09 ktP / a (Equation 5), accounting for 0.10%; urban wastewater input accounted for 32.02 ktP / a (Equation 6), accounting for 0.45%; seed input accounted for 41.0 ktP / a (Equation 7), accounting for 0.57%; and straw return input accounted for 149.53 ktP / a (Equation 8), accounting for 2.09%.

[0173] In 2011, China's total phosphorus output from farmland was 3847.94 ktP / a (Equation 9). Of this, agricultural output accounted for 2255.33 ktP / a (Equation 10), or 58.60%; straw output accounted for 996.84 ktP / a (Equation 11), or 25.90%; soil erosion output accounted for 34.4 ktP / a (Equation 12), or 0.89%; runoff output accounted for 511.32 ktP / a (Equation 13), or 13.29%; and seepage output accounted for 34.0 ktP / a (Equation 14), or 0.88%.

[0174] Calculations show that the phosphorus balance of China's farmland system in 2011 (Formula 15) was 3299.45 ktP / a, and the phosphorus use efficiency of farmland was 0.3 (Formula 16), that is, the ratio of the phosphorus content of crops produced on farmland to the phosphorus input to farmland was 0.3. The specific crop use efficiency is detailed in Table 8.

[0175] Table 8 Phosphorus use efficiency coefficients in farmland

[0176]

[0177] In summary, the calculation method of the present invention can be used to estimate the phosphorus balance and phosphorus utilization efficiency of farmland systems in different regions, different years, and different sources, which is of great significance for scientifically managing phosphorus inputs in the crop industry, improving the efficiency of phosphorus fertilizer utilization, and controlling non-point source pollution. In the present invention, the Northeast region and the Chinese farmland system are used as examples for calculation as an implementation method. It should be pointed out that there are differences in farmland systems in different regions. The present invention analyzes the situation in some regions. In fact, there are more regions with different conditions. With the development of agriculture, new factors that affect the phosphorus cycle of farmland systems may appear. For those skilled in the art, without departing from the principles described in the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for calculating phosphorus balance in a farmland system, characterized in that: The following steps are involved: S1: Obtain the phosphorus input and output data of the farmland system; S2: Based on the phosphorus input and output data of the farmland system, a database for phosphorus input, output and phosphorus balance accounting is established; S3: Evaluate phosphorus balance in cropland systems based on accounting databases; Among them, phosphorus input includes phosphorus input from chemical fertilizers, phosphorus input from agricultural fertilizers, phosphorus input from seeds, phosphorus input from straw return to fields, phosphorus input from urban wastewater irrigation, phosphorus input from atmospheric phosphorus deposition and phosphorus input from rock weathering; phosphorus output includes phosphorus output from agricultural product consumption, phosphorus output from straw harvesting, phosphorus output from soil erosion, phosphorus output from soil runoff, and phosphorus output from soil leakage; phosphorus balance is phosphorus input minus phosphorus output.

2. The method for calculating phosphorus balance in a farmland system according to claim 1, characterized in that: It also includes the calculation of phosphorus use efficiency, which is the ratio between the phosphorus content of agricultural products and the amount of phosphorus input into farmland.

3. The method for calculating phosphorus balance in a farmland system according to claim 1, characterized in that: Phosphorus input to the farmland system is calculated according to the following formula: ； Where, is the phosphorus input, unit is t P; is the fertilizer phosphorus input, unit is t P; is the phosphorus input of agricultural fertilizer, unit is t P; is the seed phosphorus input, unit is t P; is the phosphorus input for urban wastewater irrigation, in t P; is the atmospheric phosphorus deposition input, unit is t P; is the rock weathering phosphorus input, unit is t P; is the phosphorus input from returning straw to the field, unit is tP.

4. The method for calculating phosphorus balance in a farmland system according to claim 1, wherein: The calculation formula for each phosphorus input is as follows: The phosphorus input of chemical fertilizers, including the pure input of phosphate fertilizers and the phosphorus input of compound fertilizers, is as follows: （2）； Where, is the fertilizer phosphorus input, unit is t P; is the amount of phosphate fertilizer input, unit is t ; 0.3827 is phosphorus proportion; is the phosphorus input of compound fertilizer, unit is t P; 0.15 is the phosphorus content in compound fertilizer, based on N+ + The mass concentration of phosphorus is required to be between 25 and 40%, and the phosphorus content is usually between 10 and 20%, with an average value of 15%. The amount of phosphorus input into agricultural fertilizers is calculated based on the amount of animal manure returned to the fields. The calculation formula is as follows: ； Where, is the amount of phosphorus input into agricultural fertilizers, in t P; For the i Number of animals of the species, in pieces or units; For each year i Number of times the species is raised, dimensionless; For the i The amount of feces produced by a species of animal in a year, in tons; is the rate of manure return to the field, dimensionless; is the phosphorus content in feces, dimensionless; The input of atmospheric deposition phosphorus is calculated based on the deposition per unit area. The calculation formula is as follows: ； Where, is the atmospheric deposition phosphorus input, unit is t P, is the annual atmospheric deposition phosphorus input per unit area, in kg P / ha; A is the planted area, in ha; The input of phosphorus from rock weathering is calculated based on the amount of rock weathering per unit area. The calculation formula is as follows: ； Where, is the phosphorus input from rock weathering, unit is t P; is the rock weathering phosphorus input per unit area, in kg P / ha; A is the planted area, in ha; The amount of phosphorus input from urban wastewater is calculated based on the agricultural irrigation rate of urban wastewater. The calculation formula is as follows: ； Where, is the phosphorus input to urban wastewater, unit is t P; is the annual amount of urban wastewater generated, in tons; is the phosphorus content in municipal wastewater, dimensionless; is the urban wastewater treatment rate, dimensionless; The phosphorus treatment rate of urban wastewater is the proportion of phosphorus in wastewater that is recycled and reused by sewage treatment plants, etc., dimensionless; is the urban wastewater agricultural irrigation rate, dimensionless; The amount of seed phosphorus input is calculated based on the amount of seed input. The calculation formula is as follows: ； Where, is the amount of phosphorus input to seeds, unit is t P; is the amount of crop seed input for category i, in kg / ha; is the planting area of ​​crop type i, in ha; is the phosphorus content in each grain agricultural product; The phosphorus input from returning straw to the field is calculated based on the amount of straw returned to the field. The calculation formula is as follows: ； Where, is the phosphorus input of straw returned to the field, unit is t P; is the yield of type i crops, in t; is the grass-to-grain ratio of crop type i, dimensionless; is the phosphorus content in each crop straw, dimensionless; is the rate of returning crop straw to the field, dimensionless.

5. The method for calculating phosphorus balance in a farmland system according to claim 1, wherein: Phosphorus output from the cropland system was calculated using the following formula: ； Where, is the phosphorus output, unit is t P; is the phosphorus output consumed by agricultural products, unit is t P; Phosphorus output from straw harvest, in t P; is the soil erosion phosphorus output, in t P; is the soil runoff phosphorus output, in t P; is the soil leakage phosphorus output, unit is tP.

6. The method for calculating phosphorus balance in a farmland system according to claim 1, characterized in that: The calculation formula for each phosphorus output is as follows: The output of phosphorus consumed by agricultural products is calculated based on the output of agricultural products. The calculation formula is as follows: ； Where, is the output of phosphorus consumed by agricultural products, unit is t P; is the yield of type i crops, in t; is the phosphorus content in each grain agricultural product, dimensionless; The phosphorus output from straw harvest is calculated based on the amount of straw harvested. The calculation formula is as follows: ； Where, is the phosphorus output of straw harvest, unit is t P; is the yield of type i crops, in t; is the grass-to-grain ratio of crop type i, dimensionless; is the phosphorus content in each crop straw, dimensionless; is the rate of returning crop straw to the field, dimensionless; Soil loss phosphorus output, including soil erosion phosphorus output, soil seepage phosphorus output and soil runoff phosphorus output, is calculated as follows: ； ； ； Where, is the soil erosion phosphorus output, unit is t P; is the soil runoff phosphorus output, unit is tP; is the output of soil leakage phosphorus, unit is t P; is the soil erosion phosphorus output per unit area, in kg P / ha; soil runoff phosphorus output can be divided into paddy field crop With other crops Phosphorus output, unit is kg P / ha; soil leakage phosphorus output can also be divided into paddy field crop infiltration phosphorus output and other crop phosphorus output , unit is kg P / ha; A is the cultivated area of ​​farmland, is the planting area of ​​each paddy field crop, is the planting area of ​​other crops, in ha.

7. A system for calculating phosphorus balance in a farmland system, characterized in that: The system is used to implement the calculation of the method according to any one of claims 1 to 6, including: The phosphorus balance database establishment module is used to establish a database for phosphorus balance accounting in the farmland system, and includes the following sub-databases; Phosphorus input calculation module, used to calculate the phosphorus input amount of the farmland system; Phosphorus output calculation module, used to calculate the phosphorus output of the farmland system; Phosphorus balance calculation module, used to calculate the phosphorus surplus / deficit of the farmland system; Phosphorus use efficiency module, used to calculate the phosphorus use efficiency of the farmland system; The phosphorus input calculation module includes a natural process phosphorus input calculation submodule and a production material input calculation submodule, which are used to calculate the natural process phosphorus input and the production material phosphorus input respectively; the phosphorus output calculation module includes a crop absorption phosphorus output calculation submodule and a soil loss phosphorus output calculation submodule; The submodule for calculating phosphorus inputs from natural processes includes phosphorus inputs from atmospheric deposition and rock weathering; the submodule for calculating inputs from production materials includes phosphorus inputs from chemical fertilizers, agricultural fertilizers, seeds, straw return to fields, and urban wastewater irrigation; the submodule for calculating phosphorus outputs absorbed by crops includes phosphorus outputs absorbed by agricultural products and straw harvesting; the submodule for calculating phosphorus outputs from soil loss includes phosphorus outputs from soil erosion, soil runoff, and soil infiltration.

8. An electronic device comprising a processor and a memory, characterized in that: The memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory to implement the steps of the farmland system phosphorus balance accounting method according to any one of claims 1 to 6.

9. A computer-readable storage medium storing computer instructions, characterized in that: The computer instructions are used to enable a computer to execute the steps of the farmland system phosphorus balance accounting method according to any one of claims 1 to 6.

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