A nitrogen leaching risk assessment method based on farmland soil pressure

Abstract

The present invention discloses a nitrogen leaching risk assessment method based on farmland soil pressure, which relates to the field of specific data processing technology, including collecting soil auger pressure data of multiple profile soil layers with different depths on the soil to be detected by soil auger equipment to obtain original soil auger pressure data; comparing the calibration curve with the original soil auger pressure curve; determining the performance fluctuation of the soil auger equipment according to the real-time parameters of the soil auger equipment, setting the IQR coefficient based on the first fluctuation factor and the second fluctuation factor, and constructing a box plot of the original soil auger pressure data based on the IQR coefficient; determining the soil auger pressure peak value through the box plot of the original soil auger pressure data, and judging the nitrogen leaching risk according to the soil layer depth interval where the soil auger pressure peak value is located. A box plot of pressure data is constructed to filter out abnormal values, improve the adaptability of data processing, accurately determine the pressure peak value, and ensure the accuracy of the assessment of soil nitrogen leaching risk.

Description

Technical Field

[0001] The present application relates to a specific data processing technology field, and more specifically, to a nitrogen leaching risk assessment method based on farmland soil pressure. Background Art

[0002] In modern agricultural production, especially in facility agriculture, in pursuit of high yields, a highly intensive management method of "large fertilizer and large water" is often adopted. Excessive nitrogen is easily leached and migrated downward with precipitation or irrigation, seriously threatening the ecological safety of water bodies in the basin. The results of national groundwater quality monitoring from 2013 to 2017 also show that the "three nitrogens" (ammonia nitrogen, nitrite nitrogen and nitrate nitrogen) in groundwater are seriously exceeded, and nitrogen leaching loss has become an agricultural non-point source pollution problem that cannot be ignored.

[0003] Existing monitoring methods for nitrogen leaching include in-situ measurement and model fitting methods. Among them, the in-situ monitoring methods mainly include the leaching bucket method, clay head method, lysimeter method, etc., but these methods are labor-intensive and require sampling for testing, which takes a long time. The model methods mainly include DNDC, NLEAP, LEACHM, DSSAT, RZWQM, Hydrus-1D and SWAT, but they all require a large amount of monitoring data support, and there are problems such as high threshold for use and applicability. It is urgent to develop relevant simple assessment methods to achieve accurate judgment of in-situ soil nitrogen leaching risks.

[0004] In the prior art, in addition to the fact that the above-mentioned model method requires a large amount of data support and has a high threshold for use, the directly collected data will affect the accuracy of pressure data collection due to differences in equipment performance and different soil conditions, resulting in the presence of more outliers in the collected pressure data, and the data processing has poor adaptability. The presence of outliers will affect the judgment of the pressure peak, thereby reducing the accuracy and precision of soil nitrogen leaching risk assessment.

[0005] Therefore, how to improve the adaptability of data processing and the accuracy of soil nitrogen leaching risk assessment is a technical problem that needs to be solved urgently. Summary of the invention

[0006] The present invention provides a nitrogen leaching risk assessment method based on farmland soil pressure, which is used to solve the technical problems of low adaptability of data processing and poor accuracy of soil nitrogen leaching risk assessment in the prior art. The method comprises:

[0007] The soil drilling equipment is used to collect soil drilling pressure data of multiple soil layers at different depths on the soil to be tested, so as to obtain the original soil drilling pressure data and monitor the real-time parameters of the soil drilling equipment;

[0008] Selecting a calibration curve according to basic information of the soil to be tested, drawing an original soil drill pressure curve according to original soil drill pressure data, comparing the calibration curve with the original soil drill pressure curve, and determining a first fluctuation factor according to the similarity of the two curves;

[0009] determining performance fluctuations of the earth drilling device according to real-time parameters of the earth drilling device, determining a second fluctuation factor according to the performance fluctuations of the earth drilling device, setting an IQR coefficient based on the first fluctuation factor and the second fluctuation factor, and constructing a box plot of the original earth drilling pressure data based on the IQR coefficient;

[0010] The peak soil auger pressure data were analyzed by box plot, and the nitrogen leaching risk was determined based on the soil depth interval where the peak soil auger pressure was located.

[0011] In some embodiments of the present application, the calibration curve is selected according to the basic information of the soil to be tested, including:

[0012] The basic information of the soil to be tested includes moisture, density and compactness, and a comprehensive index is set according to the moisture, density and compactness. The calibration curves of different comprehensive indexes and soil drilling pressure are preset and stored in the database. The calibration curve is the soil drilling pressure range curve that changes with the depth of the soil layer.

[0013] According to the actual comprehensive index of the soil to be tested, the calibration curve corresponding to the same comprehensive index is found in the database.

[0014] In some embodiments of the present application, the calibration curve is compared with the original soil drilling pressure curve, and the first fluctuation factor is determined according to the similarity between the two curves, including:

[0015] If the original soil drill pressure curve is completely within the range of the calibration curve, the similarity between the two curves is 100%, and the first fluctuation factor is 0;

[0016] Otherwise, the portion of the original soil drilling pressure curve outside the range of the calibration curve is split into multiple excess curves according to the soil layer depth, the average difference between each excess curve and the calibration curve boundary is calculated, all average differences are integrated to determine the similarity, and a first fluctuation factor is mapped through the similarity.

[0017] In some embodiments of the present application, determining the performance fluctuation of the earth drilling equipment according to the real-time parameters of the earth drilling equipment includes:

[0018] The real-time parameters of the earth drilling equipment during the earth drilling process are obtained, and a parameter change curve of each real-time parameter changing over time is constructed, each parameter change curve is split into multiple small curves according to the fluctuation degree of each real-time parameter, and the slope change of each small curve is calculated to obtain the overall slope change average value of the parameter change curve, and the real-time parameters are divided into stable parameters and unstable parameters according to the slope change average value, and the stable parameters and unstable parameters are standardized;

[0019] Determine the performance fluctuation of earth drilling equipment through stable and unstable parameters;

[0020]

[0021] Among them, M is the performance fluctuation of the earth drilling equipment, n1 is the number of stable parameter types, α i is the performance weight of the ith stable parameter, Q i is the size of the i-th stable parameter, n2 is the number of unstable parameter types, β j is the performance weight of the jth unstable parameter, W j is the size of the i-th unstable parameter, k1 is the first constant, and M0 is the performance standard fluctuation range of the earth drilling equipment.

[0022] In some embodiments of the present application, an IQR coefficient is set based on the first fluctuation factor and the second fluctuation factor, and a box plot of the original soil drilling pressure data is constructed based on the IQR coefficient, including:

[0023]

[0024] Where D is the IQR coefficient, γ1 is the volatility weight of the larger volatility factor, max{s1, s2} is the larger of the first volatility factor and the second volatility factor, s1 is the first volatility factor, s2 is the second volatility factor, γ2 is the volatility weight of the average of the first volatility factor and the second volatility factor, is the IQR compensation coefficient obtained by mapping the larger volatility factor and the average volatility factor, and D2 is the initial IQR coefficient;

[0025] The upper and lower bounds of the box plot are determined by the IQR coefficient, and a box plot of the original soil drilling pressure data is constructed accordingly.

[0026] In some embodiments of the present application, the peak value of the soil drill pressure is determined by a box plot of the original soil drill pressure data, including:

[0027] The normal soil auger pressure data and the abnormal soil auger pressure data are distinguished by the upper and lower bounds in the box plot of the original soil auger pressure data, and the soil auger pressure peak is determined in the normal soil auger pressure data, and the abnormal soil auger pressure data is removed.

[0028] In some embodiments of the present application, the nitrogen leaching risk is determined according to the soil layer depth interval where the soil drilling pressure peak is located, including:

[0029] Obtain other soil conditions, including groundwater flow and soil barriers, and comprehensively judge the nitrogen leaching risk based on groundwater flow, soil barriers and soil depth range.

[0030] Correspondingly, the present application also provides a simple assessment system for the risk of nitrogen leaching from farmland soil, including:

[0031] The soil drilling module is used to collect soil drilling pressure data of multiple soil layers at different depths on the soil to be tested through the soil drilling equipment, obtain the original soil drilling pressure data, and monitor the real-time parameters of the soil drilling equipment;

[0032] A calibration module is used to select a calibration curve according to the basic information of the soil to be tested, draw an original soil auger pressure curve according to the original soil auger pressure data, compare the calibration curve with the original soil auger pressure curve, and determine a first fluctuation factor according to the similarity of the two curves;

[0033] A construction module is used to determine the performance fluctuation of the earth drilling device according to the real-time parameters of the earth drilling device, determine the second fluctuation factor according to the performance fluctuation of the earth drilling device, set the IQR coefficient based on the first fluctuation factor and the second fluctuation factor, and construct a box plot of the original earth drilling pressure data based on the IQR coefficient;

[0034] The evaluation module is used to determine the soil auger pressure peak value through the box plot of the original soil auger pressure data, and to judge the nitrogen leaching risk according to the soil layer depth interval where the soil auger pressure peak value is located.

[0035] By applying the above technical scheme, soil drill pressure data of multiple soil layers with different depths are collected on the soil to be tested by a soil drill equipment to obtain original soil drill pressure data, and the real-time parameters of the soil drill equipment are monitored; a calibration curve is selected according to the basic information of the soil to be tested, an original soil drill pressure curve is drawn according to the original soil drill pressure data, the calibration curve is compared with the original soil drill pressure curve, and a first fluctuation factor is determined according to the similarity of the two curves; the performance fluctuation of the soil drill equipment is determined according to the real-time parameters of the soil drill equipment, the second fluctuation factor is determined according to the performance fluctuation of the soil drill equipment, the IQR coefficient is set based on the first fluctuation factor and the second fluctuation factor, and a box plot of the original soil drill pressure data is constructed based on the IQR coefficient; the soil drill pressure peak value is determined by the box plot of the original soil drill pressure data, and the nitrogen leaching risk is judged according to the soil layer depth interval where the soil drill pressure peak value is located.

[0036] Beneficial effects: This application sets the IQR coefficient based on the first fluctuation factor and the second fluctuation factor, comprehensively considers the impact of soil drilling equipment and soil conditions on data collection, and sets a reasonable IQR coefficient, thereby constructing a box plot of pressure data, filtering out abnormal values, improving the adaptability of data processing, accurately determining the pressure peak, and ensuring the accuracy of the assessment of soil nitrogen leaching risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 A schematic flow chart of a nitrogen leaching risk assessment method based on farmland soil pressure proposed in an embodiment of the present invention is shown;

[0039] Figure 2 A structural schematic diagram of a farmland soil nitrogen leaching risk assessment system proposed in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0040] Example 1

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0042] The embodiment of the present application provides a nitrogen leaching risk assessment method based on farmland soil pressure. The mechanical composition of soil is the percentage rate of mineral particles at each level in the soil. It reflects the size and quantity of soil mineral particles and has a significant impact on the soil nitrogen leaching process. The soil texture (sand, loam, clay) can be determined by the mechanical composition of soil. Sand has larger particles, more pores, good water permeability but poor water retention capacity, and relatively less nutrients; loam is a soil type between sand and clay. It contains particles of different sizes and moderate voids, so it has good drainage and water retention, and is the most suitable soil for agricultural cultivation. Clay has very fine particles, so its air permeability and water permeability are poor, but its water retention and water retention are strong. Clay is more viscous, and its hardness is also higher after drying, which is not easy to cultivate. The soil compaction degree is clay>loam>sand, so the soil texture can be judged by the difficulty of sampling (pressure peak), and the nutrient retention status can be judged according to the soil texture, and then the risk of nitrogen underground leaching can be evaluated.

[0043] like Figure 1 As shown, the method comprises the following steps:

[0044] Step S101, collecting soil drilling pressure data of multiple soil layers at different depths on the soil to be tested by using a soil drilling device to obtain original soil drilling pressure data and monitor real-time parameters of the soil drilling device.

[0045] In this embodiment, the electric soil drill is driven by a motor, which is highly efficient and suitable for medium-sized area surveys. The hydraulic soil drill uses hydraulic power, which is most efficient and suitable for large-area surveys and sampling. The soil drill pressure data is collected by installing sensors on the soil drill equipment.

[0046] Step S102, selecting a calibration curve according to the basic information of the soil to be tested, drawing an original soil drill pressure curve according to the original soil drill pressure data, comparing the calibration curve with the original soil drill pressure curve, and determining a first fluctuation factor according to the similarity between the two curves.

[0047] In this embodiment, it is determined which soil physical properties have a significant impact on the pressure reading, such as soil moisture, compactness, density, etc. Soil drilling tests are performed at multiple locations and pressure data is recorded. At the same time, soil samples are collected from each test point and the soil moisture, density, compactness, etc. are measured in the laboratory. These soil properties are integrated into a comprehensive index, a calibration curve, and the relationship between the comprehensive index value and the pressure data measured on site is analyzed. A calibration curve is established using statistical methods (such as regression analysis), usually with the pressure reading as the vertical axis and the soil layer depth as the horizontal axis, to construct a calibration curve within a range, which is an area from the minimum to the maximum value, and the closest curve is selected by the comprehensive index. The first fluctuation factor is the difference compared with the calibration curve of the soil to determine the fluctuation.

[0048] In some embodiments of the present application, the calibration curve is selected according to the basic information of the soil to be tested, including:

[0049] The basic information of the soil to be tested includes moisture, density and compactness, and a comprehensive index is set according to the moisture, density and compactness. The calibration curves of different comprehensive indexes and soil drilling pressure are preset and stored in the database. The calibration curve is the soil drilling pressure range curve that changes with the depth of the soil layer.

[0050] According to the actual comprehensive index of the soil to be tested, the calibration curve corresponding to the same comprehensive index is found in the database.

[0051] In this embodiment, the comprehensive index can be determined by weighted average of the above-mentioned attributes, and a calibration curve corresponding to the same or closest comprehensive index is found in the database according to the actual comprehensive index.

[0052] In some embodiments of the present application, the calibration curve is compared with the original soil drilling pressure curve, and the first fluctuation factor is determined according to the similarity between the two curves, including:

[0053] If the original soil drill pressure curve is completely within the range of the calibration curve, the similarity between the two curves is 100%, and the first fluctuation factor is 0;

[0054] Otherwise, the portion of the original soil drilling pressure curve outside the range of the calibration curve is split into multiple excess curves according to the soil layer depth, the average difference between each excess curve and the calibration curve boundary is calculated, all average differences are integrated to determine the similarity, and a first fluctuation factor is mapped through the similarity.

[0055] In this embodiment, the original soil drilling pressure curve is completely within the range of the calibration curve, indicating that it is consistent with the calibration curve and has a small fluctuation. If it exceeds the calibration curve, it means that the fluctuation is large and needs to be taken into account. The larger the integrated average difference is, the smaller the similarity is, and the larger the first fluctuation factor is.

[0056] Step S103, determining the performance fluctuation of the earth drilling equipment according to the real-time parameters of the earth drilling equipment, determining the second fluctuation factor through the performance fluctuation of the earth drilling equipment, setting the IQR coefficient based on the first fluctuation factor and the second fluctuation factor, and constructing a box plot of the original earth drilling pressure data based on the IQR coefficient.

[0057] In this embodiment, the performance fluctuation of the earth drilling equipment may be affected by a variety of operating parameters, and the following are some key operating parameters:

[0058] Drill speed: The speed of the drill affects the cutting and compression behavior of the soil, which affects the collection of pressure data. Unstable drill speed may cause inconsistent pressure readings.

[0059] Torque: Torque is the force applied when the drill bit rotates, which affects the penetration of the drill bit and the degree of soil fragmentation. Instability in torque may cause pressure fluctuations.

[0060] Drilling pressure: Drilling pressure refers to the vertical pressure exerted by the drill bit on the soil. Fluctuations in drilling pressure will directly affect the collection of pressure data.

[0061] Vibration: Vibration during drilling can affect the readings of the pressure sensors, causing the data to fluctuate.

[0062] Speed: For electric or hydraulic earth drills, the stability of the speed is also very important. The change of speed will affect the penetration of the drill bit and the stress state of the soil.

[0063] Cooling system: The drill bit and drilling machine may overheat when running for a long time, and the performance of the cooling system will affect the working efficiency and stability of the equipment.

[0064] Power supply stability: For electric earth drills, the stability of the power supply will affect the performance of the motor, which in turn affects the drilling speed and torque.

[0065] Hydraulic system pressure: For hydraulic earth drills, the pressure stability of the hydraulic system will affect the performance of the hydraulic motor, which in turn affects the drilling speed and torque.

[0066] In this embodiment, the second fluctuation factor represents the performance fluctuation of the earth drilling equipment, and the IQR coefficient is set by the fluctuations of the first fluctuation factor and the second fluctuation factor. The abnormal values ​​and normal values ​​of the pressure data are described by a box plot. Generally speaking, the box plot includes a lower bound, a lower quartile Q1, a median Q2, an upper quartile Q3 and an upper bound. The lower quartile Q1, the median Q2, and the upper quartile Q3 represent the first quartile, the second quartile, and the third quartile, respectively, which are actually the 25th, 50th, and 75th percentiles. The quartile difference IQR = Q3-Q1, which is usually defined as the lower bound Q1-1.5IQR and the upper bound Q3+1.5IQR, but this is the default data that obeys the normal distribution. Generally speaking, there are few data that completely obey the normal distribution. Here, in order to ensure the accuracy of the box plot, the IQR coefficient is adjusted. The data between the upper and lower bounds are normal data, and the data outside the upper and lower bounds are abnormal data.

[0067] In the box plot, the upper and lower bounds are defined based on the interquartile range (IQR), and 1.5 times the IQR is usually used as the criterion for outliers. This 1.5 times is a rule of thumb that assumes that the data follows a normal distribution. In this case, about 99.3% of the data will fall between Q1-1.5IQR and Q3+1.5IQR. However, due to the fluctuations of both earth drilling equipment and soil, this coefficient needs to be adjusted to better screen outliers. For example, if the equipment performance fluctuates greatly, consider using a more relaxed IQR coefficient (such as 1.2 or 1.3 times the IQR). If the equipment performance fluctuates less, consider using a stricter IQR coefficient (such as 1.5 or 1.8 times the IQR).

[0068] In some embodiments of the present application, determining the performance fluctuation of the earth drilling equipment according to the real-time parameters of the earth drilling equipment includes:

[0069] The real-time parameters of the earth drilling equipment during the earth drilling process are obtained, and a parameter change curve of each real-time parameter changing over time is constructed, each parameter change curve is split into multiple small curves according to the fluctuation degree of each real-time parameter, and the slope change of each small curve is calculated to obtain the overall slope change average value of the parameter change curve, and the real-time parameters are divided into stable parameters and unstable parameters according to the slope change average value, and the stable parameters and unstable parameters are standardized;

[0070] Determine the performance fluctuation of earth drilling equipment through stable and unstable parameters;

[0071]

[0072] Among them, M is the performance fluctuation of the earth drilling equipment, n1 is the number of stable parameter types, α i is the performance weight of the ith stable parameter, Q i is the size of the i-th stable parameter, n2 is the number of unstable parameter types, β j is the performance weight of the jth unstable parameter, W j is the size of the i-th unstable parameter, k1 is the first constant, and M0 is the performance standard fluctuation range of the earth drilling equipment.

[0073] In this embodiment, the performance fluctuation represented by the stable parameter is corrected by the unstable parameter. When it is less than M0, M=0. The value range is between 0.89-1.21.

[0074] In some embodiments of the present application, an IQR coefficient is set based on the first fluctuation factor and the second fluctuation factor, and a box plot of the original soil drilling pressure data is constructed based on the IQR coefficient, including:

[0075]

[0076] Where D is the IQR coefficient, γ1 is the volatility weight of the larger volatility factor, max{s1, s2} is the larger of the first volatility factor and the second volatility factor, s1 is the first volatility factor, s2 is the second volatility factor, γ2 is the volatility weight of the average of the first volatility factor and the second volatility factor, is the IQR compensation coefficient obtained by mapping the larger volatility factor and the average volatility factor, and D2 is the initial IQR coefficient;

[0077] The upper and lower bounds of the box plot are determined by the IQR coefficient, and a box plot of the original soil drilling pressure data is constructed accordingly.

[0078] In this embodiment, the compensation coefficient is determined according to the larger value and the average value of the two factors, and the initial IQR coefficient is 1.5.

[0079] Step S104, determining the soil auger pressure peak value through the box plot of the original soil auger pressure data, and judging the nitrogen leaching risk according to the soil layer depth interval where the soil auger pressure peak value is located.

[0080] In some embodiments of the present application, the peak value of the soil drill pressure is determined by a box plot of the original soil drill pressure data, including:

[0081] The normal soil auger pressure data and the abnormal soil auger pressure data are distinguished by the upper and lower bounds in the box plot of the original soil auger pressure data, and the soil auger pressure peak is determined in the normal soil auger pressure data, and the abnormal soil auger pressure data is removed.

[0082] In some embodiments of the present application, the nitrogen leaching risk is determined according to the soil layer depth interval where the soil drilling pressure peak is located, including:

[0083] Obtain other soil conditions, including groundwater flow and soil barriers, and comprehensively judge the nitrogen leaching risk based on groundwater flow, soil barriers and soil depth.

[0084] As shown in Table 1

[0085]

[0086]

[0087] By applying the above technical scheme, soil drill pressure data of multiple soil layers with different depths are collected on the soil to be tested by a soil drill equipment to obtain original soil drill pressure data, and the real-time parameters of the soil drill equipment are monitored; a calibration curve is selected according to the basic information of the soil to be tested, an original soil drill pressure curve is drawn according to the original soil drill pressure data, the calibration curve is compared with the original soil drill pressure curve, and a first fluctuation factor is determined according to the similarity of the two curves; the performance fluctuation of the soil drill equipment is determined according to the real-time parameters of the soil drill equipment, the second fluctuation factor is determined according to the performance fluctuation of the soil drill equipment, the IQR coefficient is set based on the first fluctuation factor and the second fluctuation factor, and a box plot of the original soil drill pressure data is constructed based on the IQR coefficient; the soil drill pressure peak value is determined by the box plot of the original soil drill pressure data, and the nitrogen leaching risk is judged according to the soil layer depth interval where the soil drill pressure peak value is located. This application sets the IQR coefficient based on the first fluctuation factor and the second fluctuation factor, comprehensively considers the impact of soil drilling equipment and soil conditions on data collection, and sets a reasonable IQR coefficient, thereby constructing a box plot of pressure data, filtering out abnormal values, improving the adaptability of data processing, accurately determining the pressure peak, and ensuring the accuracy of the assessment of soil nitrogen leaching risk.

[0088] Through the description of the above implementation methods, those skilled in the art can clearly understand that the present invention can be implemented by hardware, or by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present invention can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each implementation scenario of the present invention.

[0089] Correspondingly, this application also provides a simple assessment system for the risk of nitrogen leaching in farmland soil, such as Figure 2 As shown, including:

[0090] The soil drilling module is used to collect soil drilling pressure data of multiple soil layers at different depths on the soil to be tested through the soil drilling equipment, obtain the original soil drilling pressure data, and monitor the real-time parameters of the soil drilling equipment;

[0091] A calibration module is used to select a calibration curve according to the basic information of the soil to be tested, draw an original soil auger pressure curve according to the original soil auger pressure data, compare the calibration curve with the original soil auger pressure curve, and determine a first fluctuation factor according to the similarity of the two curves;

[0092] A construction module is used to determine the performance fluctuation of the earth drilling device according to the real-time parameters of the earth drilling device, determine the second fluctuation factor according to the performance fluctuation of the earth drilling device, set the IQR coefficient based on the first fluctuation factor and the second fluctuation factor, and construct a box plot of the original earth drilling pressure data based on the IQR coefficient;

[0093] The evaluation module is used to determine the soil auger pressure peak value through the box plot of the original soil auger pressure data, and to judge the nitrogen leaching risk according to the soil layer depth interval where the soil auger pressure peak value is located, and to provide a solution.

[0094] In order to further explain the technical idea of ​​the present invention, the technical solution of the present invention is now described in combination with specific application scenarios.

[0095] This application is based on the soil drill pressure records when sampling at different levels of soil (soil layer depth) at the point, and the corresponding data is processed. The nitrogen leaching risk can be evaluated during sampling, and locally applicable nitrogen leaching prevention and control technology is given. The evaluation method described in this patent helps to reduce nitrogen environmental losses, improve farmland soil, and protect water resources.

[0096] With the existing technology, in-situ soil collection by soil drilling is a conventional method for field background surveys. The collected air-dried soil from the farmland is sieved through a 2mm sieve, and the soil mechanical composition is determined by the densitometer method to determine the soil texture. This is time-consuming and labor-intensive. If the texture profile can be directly obtained during the in-situ soil collection process, pollution prevention and control and farmland improvement technologies suitable for the local plot can be directly obtained.

[0097] The soil monitoring range for vegetable crops is 0-1m, the soil profile monitoring range for field crops such as wheat and corn is 0-2m, and the depth for gardens with fruit trees can be extended to 3m.

[0098] 1. If the pressure peak appears in the surface soil <30cm (<100cm in orchards), it means that the surface soil is compacted. Soil improvement is the main measure, supplemented by nitrogen leaching risk prevention and control. The main technologies that can be used are precision fertilization, organic fertilizer application, biochar and other improvers, straw return to the field, deep plowing, etc., to improve soil structure and increase soil permeability and water retention.

[0099] 2. If the pressure peak occurs in the sub-surface soil of 30-60cm (100-200cm in orchards), soil improvement is the main method, supplemented by nitrogen leaching risk prevention and control. Deep loosening can be used to break the plow bottom layer, and organic fertilizer and straw return to the field can be used. If the soil is salinized, deep loosening can significantly alleviate the harm of salinization after breaking the plow bottom layer.

[0100] 3. If the pressure peak occurs in the 60-100cm soil layer (200-300cm in orchards), nitrogen leaching control technology should be used as the main method for field or vegetable soil, such as precision fertilization, water-saving irrigation, organic fertilizer application, straw return to the field, intercropping of deep-rooted and shallow-rooted crops, etc., to prevent and control nutrient leaching from deep layers. For orchards, soil improvement is still the main method, using deep loosening methods to break the plow bottom layer, promote root growth downward, and increase crop yields.

[0101] 4. If the pressure peak occurs in the 100-200cm soil layer (in orchards it occurs at >300cm), the risk of nitrogen leaching is low and the number of monitoring points can be reduced.

[0102] If no peak appears in the 0-200cm range, it means that the soil is generally sandy and nitrogen leaching is likely to occur. It is necessary to increase monitoring points and adopt concealed pipe drainage recovery and substrate planting methods.

[0103] 5. If groundwater appears at 60cm-200cm when the soil drill is pulled out, it means that the risk of nitrogen leaching into shallow groundwater in the area is high, and non-point source pollution is prone to occur. In this area, attention should be paid to the precise application of nitrogen fertilizers, and the application of controlled-release fertilizers is recommended.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A nitrogen leaching risk assessment method based on farmland soil pressure, characterized in that: include: The soil drilling equipment is used to collect soil drilling pressure data of multiple soil layers at different depths on the soil to be tested, so as to obtain the original soil drilling pressure data and monitor the real-time parameters of the soil drilling equipment; Selecting a calibration curve according to basic information of the soil to be tested, drawing an original soil drill pressure curve according to original soil drill pressure data, comparing the calibration curve with the original soil drill pressure curve, and determining a first fluctuation factor according to the similarity of the two curves; determining performance fluctuations of the earth drilling device according to real-time parameters of the earth drilling device, determining a second fluctuation factor according to the performance fluctuations of the earth drilling device, setting an IQR coefficient based on the first fluctuation factor and the second fluctuation factor, and constructing a box plot of the original earth drilling pressure data based on the IQR coefficient; The peak soil auger pressure data were analyzed by box plot, and the nitrogen leaching risk was determined based on the soil depth interval where the peak soil auger pressure was located.

2. A nitrogen leaching risk assessment method based on farmland soil pressure as claimed in claim 1, characterized in that: The calibration curve is selected based on the basic information of the soil to be tested, including: The basic information of the soil to be tested includes moisture, density and compactness, and a comprehensive index is set according to the moisture, density and compactness. The calibration curves of different comprehensive indexes and soil drilling pressure are preset and stored in the database. The calibration curve is the soil drilling pressure range curve that changes with the depth of the soil layer. According to the actual comprehensive index of the soil to be tested, the calibration curve corresponding to the same comprehensive index is found in the database.

3. A nitrogen leaching risk assessment method based on farmland soil pressure as claimed in claim 2, characterized in that: Compare the calibration curve with the original soil drilling pressure curve, and determine the first fluctuation factor based on the similarity between the two curves, including: If the original soil drill pressure curve is completely within the range of the calibration curve, the similarity between the two curves is 100%, and the first fluctuation factor is 0; Otherwise, the portion of the original soil drilling pressure curve outside the range of the calibration curve is split into multiple excess curves according to the soil layer depth, the average difference between each excess curve and the calibration curve boundary is calculated, all average differences are integrated to determine the similarity, and a first fluctuation factor is mapped through the similarity.

4. The nitrogen leaching risk assessment method based on farmland soil pressure according to claim 1, characterized in that: Determine the performance fluctuation of the earth drilling equipment based on the real-time parameters of the earth drilling equipment, including: The real-time parameters of the earth drilling equipment during the earth drilling process are obtained, and a parameter change curve of each real-time parameter changing over time is constructed, each parameter change curve is split into multiple small curves according to the fluctuation degree of each real-time parameter, and the slope change of each small curve is calculated to obtain the overall slope change average value of the parameter change curve, and the real-time parameters are divided into stable parameters and unstable parameters according to the slope change average value, and the stable parameters and unstable parameters are standardized; Determine the performance fluctuation of earth drilling equipment through stable and unstable parameters; Among them, M is the performance fluctuation of the earth drilling equipment, n1 is the number of stable parameter types, α i is the performance weight of the ith stable parameter, Q i is the size of the i-th stable parameter, n2 is the number of unstable parameter types, β j is the performance weight of the jth unstable parameter, W j is the size of the i-th unstable parameter, k1 is the first constant, and M0 is the performance standard fluctuation range of the earth drilling equipment.

5. A nitrogen leaching risk assessment method based on farmland soil pressure as claimed in claim 4, characterized in that: The IQR coefficient is set based on the first fluctuation factor and the second fluctuation factor, and a box plot of the original soil drilling pressure data is constructed based on the IQR coefficient, including: Where D is the IQR coefficient, γ1 is the volatility weight of the larger volatility factor, max{s1, s2} is the larger of the first volatility factor and the second volatility factor, s1 is the first volatility factor, s2 is the second volatility factor, γ2 is the volatility weight of the average of the first volatility factor and the second volatility factor, is the IQR compensation coefficient obtained by mapping the larger volatility factor and the average volatility factor, and D2 is the initial IQR coefficient; The upper and lower bounds of the box plot are determined by the IQR coefficient, and a box plot of the original soil drilling pressure data is constructed accordingly.

6. A method for assessing nitrogen leaching risk based on farmland soil pressure as claimed in claim 5, characterized in that: The peak soil auger pressure is determined by a box plot of the raw soil auger pressure data, including: The normal soil auger pressure data and the abnormal soil auger pressure data are distinguished by the upper and lower bounds in the box plot of the original soil auger pressure data, and the soil auger pressure peak is determined in the normal soil auger pressure data, and the abnormal soil auger pressure data is removed.

7. The method for assessing nitrogen leaching risk based on farmland soil pressure according to claim 1, characterized in that: The nitrogen leaching risk is determined based on the soil depth range where the soil drilling pressure peak is located, including: Obtain other soil conditions, including groundwater flow and soil barriers, and comprehensively judge the nitrogen leaching risk based on groundwater flow, soil barriers and soil depth range.

8. A farmland soil nitrogen leaching risk assessment system, characterized in that: include: The soil drilling module is used to collect soil drilling pressure data of multiple soil layers at different depths on the soil to be tested through the soil drilling equipment, obtain the original soil drilling pressure data, and monitor the real-time parameters of the soil drilling equipment; A calibration module is used to select a calibration curve according to the basic information of the soil to be tested, draw an original soil auger pressure curve according to the original soil auger pressure data, compare the calibration curve with the original soil auger pressure curve, and determine a first fluctuation factor according to the similarity of the two curves; A construction module is used to determine the performance fluctuation of the earth drilling device according to the real-time parameters of the earth drilling device, determine the second fluctuation factor according to the performance fluctuation of the earth drilling device, set the IQR coefficient based on the first fluctuation factor and the second fluctuation factor, and construct a box plot of the original earth drilling pressure data based on the IQR coefficient; The evaluation module is used to determine the soil auger pressure peak value through the box plot of the original soil auger pressure data, and to judge the nitrogen leaching risk according to the soil layer depth interval where the soil auger pressure peak value is located.

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