Polar coordinate-based crop nutrient efficiency evaluation method

Abstract

The invention belongs to the technical field of crop planting, and particularly relates to a polar coordinate-based crop nutrient efficiency evaluation method, which comprises the following steps of: establishing a polar coordinate system by taking the yield of a to-be-tested variety in a nutrient-deficient land parcel as a horizontal coordinate, the yield of a normal land parcel as a vertical coordinate and the average yield of a plurality of contrast varieties as an original point; based on the established polar coordinate system, obtaining polar coordinates of the to-be-tested variety; and calculating a projection difference according to the polar coordinate data of the to-be-tested variety, and evaluating the nutrient efficiency of the to-be-tested variety by using the projection difference. According to the method provided by the invention, the crop nutrient efficiency can be accurately and rapidly evaluated, chemical component detection is not needed, the cost is low, the operation is easy, and results at different places have comparability.

Description

Technical Field

[0001] The invention belongs to the technical field of crop planting, and in particular relates to a crop nutrient efficiency evaluation method based on polar coordinates. Background Art

[0002] The application of chemical synthetic fertilizers has greatly increased crop yields and ensured global food security. Cultivating nutrient-efficient crop varieties is an important measure to improve crop nutrient utilization efficiency, which is inseparable from the evaluation technology and calculation methods of crop nutrient efficiency. At present, indicators such as fertilizer partial productivity, agronomic fertilizer utilization rate, fertilizer recovery rate and nutrient physiological utilization rate are often used to measure crop nutrient efficiency. However, these methods have the following defects:

[0003] (1) Partial productivity of fertilizers

[0004] Fertilizer partial productivity = crop yield / fertilizer application amount

[0005] Obviously, this indicator is significantly affected by soil factors. There are huge differences in the nutrient supply capacity (nutrient effectiveness) of different regions and different soils, resulting in poor reliability in cross-regional and horizontal comparisons. Specifically, in areas with fertile soils, crop nutrient efficiency is underestimated, while in areas with poor soils, crop nutrient efficiency is overestimated. Therefore, the partial productivity of fertilizers is limited by the soil and climatic conditions of the test site, and the comparability of results in different locations is poor.

[0006] (2) Utilization rate of agricultural fertilizers

[0007] Agrochemical fertilizer utilization rate = (yield in fertilized area - yield in unfertilized area) / fertilizer amount

[0008] This indicator introduces the yield of the unfertilized area as a control, which avoids the influence of soil factors to a certain extent, but ignores the genotypic differences in crop responses to nutrient availability, and there is still a lack of reliable reference for comparisons between different regions and different varieties.

[0009] (3) Fertilizer recovery rate and nutrient physiological utilization rate

[0010] Fertilizer recovery rate = (nutrient accumulation of harvested organs of crops in the fertilized area - nutrient accumulation of harvested organs of crops in the unfertilized area) / fertilizer amount

[0011] Physiological utilization rate of nutrients = biomass of harvested crop organs / nutrient accumulation of crops

[0012] Fertilizer recovery rate and nutrient physiological utilization rate measure crop nutrient efficiency from the perspectives of nutrient absorption and assimilation respectively. However, the calculation method relies on chemical analysis. Samples must undergo multiple processing steps such as drying, crushing, digestion, and chemical measurement (such as Kjeldahl nitrogen determination, flame combustion method for potassium, and vanadium molybdenum yellow colorimetry for phosphorus) to obtain nutrient content data, which is costly and time-consuming. Summary of the invention

[0013] In view of the above technical problems, the present invention proposes a crop nutrient efficiency evaluation method based on polar coordinates and vector analysis, which can achieve accurate and rapid evaluation of crop nutrient efficiency. It does not require chemical composition testing, has low cost, is easy to operate, and the results at different locations are comparable.

[0014] The specific technical solutions provided by the present invention are as follows:

[0015] The present invention provides a crop nutrient efficiency evaluation method based on polar coordinates, comprising the following steps:

[0016] A polar coordinate system is established with the yield of the tested variety in the nutrient-deficient plot as the horizontal axis, the yield of the normal plot as the vertical axis, and the average yield of several control varieties as the origin;

[0017] Based on the established polar coordinate system, the polar coordinates of the tested variety are obtained;

[0018] The projection difference is calculated with the polar coordinate data of the tested variety, and the nutrient efficiency of the tested variety is evaluated using the projection difference.

[0019] As a preferred embodiment of the present invention, the polar coordinate data of the variety to be tested includes a radius of r and a polar angle of θ 0 The feature vector of .

[0020] As a preferred embodiment of the present invention, the polar coordinates of the jth tested variety are:

[0021]

[0022]

[0023] Among them, r j is the radius of the jth tested variety, θ j is the polar angle of the jth tested variety, Tj N0 is the yield of the jth tested variety in the nutrient-deficient plot, Tj N225 is the yield of the jth tested variety in a normal plot, Ci N0 is the yield of the ith control variety in the nutrient-deficient plot, Ci N225 is the yield of the ith control variety in the normal plot, and n is the number of control varieties.

[0024] As a preferred embodiment of the present invention, the calculation formula of the projection difference is:

[0025] PD=sinθ 0 -cosθ 0 *r

[0026] Where PD is the projection difference, θ 0 is the polar angle in the polar coordinate data of the tested variety, 0≤θ 0 <360°, r is the radius in the polar coordinate data of the tested variety.

[0027] As a preferred embodiment of the present invention, the standard for evaluating the crop nutrient efficiency by the projection difference is:

[0028] When PD < 0, the nutrient efficiency of the tested variety is lower than that of the control variety;

[0029] When PD = 0, the nutrient efficiency of the tested variety is equal to that of the control variety;

[0030] When PD>0, the nutrient efficiency of the tested variety is higher than that of the control variety.

[0031] As a preferred embodiment of the present invention, the polar angle of the polar coordinate data of the tested variety is used as an indicator to evaluate the yield potential of the tested variety.

[0032] More preferably, the evaluation criteria for evaluating the yield potential of the tested variety by polar angle are:

[0033] When 0<θ 0 When the angle is less than 180°, the yield potential of the tested variety is higher than that of the control variety;

[0034] When 180°<θ 0 When the angle is less than 360°, the yield potential of the tested variety is lower than that of the control variety.

[0035] As a preferred embodiment of the present invention, the polar angle of the polar coordinate data of the tested variety and the projection difference are used as indicators to comprehensively evaluate the nutrient efficiency and yield potential of the tested variety.

[0036] More preferably, the evaluation criteria for comprehensively evaluating the nutrient efficiency and yield potential of the tested varieties are:

[0037] When PD>0 and 45°<θ 0 When the angle is less than 180°, the nutrient efficiency and yield potential of the tested varieties are higher than those of the control varieties;

[0038] When PD>0 and 180°<θ 0 When the temperature is less than 225°, the nutrient efficiency of the tested varieties is higher than that of the control varieties, but the yield potential is lower than that of the control varieties;

[0039] When PD<0 and 0°<θ 0 When the temperature is less than 45°, the nutrient efficiency of the tested varieties is lower than that of the control varieties, but the yield potential is higher than that of the control varieties;

[0040] When PD<0 and 225°<θ 0 When the angle was less than 360°, the nutrient efficiency and yield potential of the tested varieties were lower than those of the control varieties.

[0041] As a preferred embodiment of the present invention, the nutrient efficiency of crops refers to the absorption and utilization of nutrients such as nitrogen, phosphorus, potassium, calcium, magnesium, zinc, etc. by crops.

[0042] As a preferred embodiment of the present invention, the crops include but are not limited to corn, wheat, rice, soybean or melon, fruit and vegetable plants.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] The method provided by the present invention utilizes polar coordinates and vector analysis to establish a crop nutrient efficiency assessment method that does not rely on chemical component detection from the perspective of crop response to fertilizer input. It has the advantages of low cost, short cycle, easy operation, and strong comparability.

[0045] The method provided by the present invention can be used to evaluate the crop nutrient efficiency of macronutrients such as nitrogen, phosphorus, potassium, etc., and is applicable to crops including but not limited to corn, rice, wheat, or fruits and vegetables. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a method for assessing crop nutrient efficiency and yield potential. DETAILED DESCRIPTION

[0047] The exemplary embodiments of the present disclosure will be described in more detail below. Although the exemplary embodiments of the present disclosure are shown below, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0048] Existing technologies mostly use indicators such as fertilizer partial productivity, agronomic fertilizer utilization rate, fertilizer recovery rate and nutrient physiological utilization rate to measure crop nutrient efficiency. However, these methods have the following defects:

[0049] The partial productivity of fertilizers is limited by the soil and climatic conditions of the test sites, and the comparability of results in different sites is poor; the agricultural fertilizer utilization rate ignores the genotypic differences in crop responses to nutrient availability, and there is still a lack of reliable reference for comparisons between different regions and different varieties; the calculation method of fertilizer recovery rate and nutrient physiological utilization rate relies on chemical analysis, and samples must undergo multiple processing steps such as drying, crushing, digestion, and chemical measurement to obtain nutrient content data, which is costly and time-consuming.

[0050] Based on this, the present invention provides a crop nutrient efficiency evaluation method based on polar coordinates, comprising the following steps:

[0051] A polar coordinate system is established with the yield of the tested variety in the nutrient-deficient plot as the horizontal axis, the yield of the normal plot as the vertical axis, and the average yield of several control varieties as the origin;

[0052] Based on the established polar coordinate system, the polar coordinates of the tested variety are obtained;

[0053] The projection difference is calculated with the polar coordinate data of the tested variety, and the nutrient efficiency of the tested variety is evaluated using the projection difference.

[0054] The evaluation method provided by the present invention can realize accurate and rapid evaluation of crop nutrient efficiency, does not require chemical component testing, is low-cost, easy to operate, and the results at different locations are comparable.

[0055] The following describes the invention in conjunction with specific embodiments.

[0056] The evaluation of crop nutrient efficiency based on polar coordinates includes the following steps:

[0057] (1) Take the nitrogen nutrient efficiency of corn as an example.

[0058] The test was conducted on nitrogen-deficient plots that had not been fertilized with nitrogen for more than five consecutive years and on normal plots where the nitrogen fertilizer application rate was 225kgN / ha (i.e., the internationally recognized upper limit of safe application). The test materials were m test varieties (marked as T1, T2, T3...Tm) and n control varieties (marked as C1, C2, C3...Cn). The control varieties and quantity, tillage methods, planting areas, planting density, phosphorus and potassium fertilizer application, pest and disease management, harvest storage and other agronomic measures and links refer to the "Major Crop Variety Approval Measures" revised in 2022.

[0059] (2) In the nitrogen-deficient plot, the yields of the m tested varieties were T1 N0 、T2 N0 、T3 N0 ...Tm N0 The yields of n control varieties are C1 N0 、C2 N0、C3 N0 ……Cn N0 ; In normal plots, the yields of the m tested varieties are T1 N225 、T2 N225 、T3 N225 ...Tm N225 The yields of n control varieties are C1 N225 、C2 N225 、C3 N225 ……Cn N225 .

[0060] (3) Establish a polar coordinate system with the yield of the tested variety in the nitrogen-deficient plot as the horizontal axis (x-axis), the yield of the normal plot as the vertical axis (y-axis), and the average yield of the n control varieties as the origin (also called the pole). The polar coordinates of the jth tested variety are:

[0061]

[0062]

[0063] At this time, each variety to be tested has a radius of r and a polar angle of θ. 0 The characteristic vector of , i represents the i-th control variety.

[0064] Nutrient efficiency is expressed as the yield increase from nitrogen-deficient plots to normal plots. If the increase in the test variety is greater than that of the control variety, the nutrient efficiency of the test variety is higher than that of the control variety; if the increase in the test variety is less than that of the control variety, the nutrient efficiency of the test variety is lower than that of the control variety.

[0065] Projection differential (PD) can be used to measure crop nutrient efficiency and is calculated as:

[0066] PD=sinθ 0 -cosθ 0 *r

[0067] Among them, θ 0 is the polar angle in the crop polar coordinates, r is the radius in the crop polar coordinates, θ 0 The value range is [0, 360°), that is, 0≤θ 0 <360°.

[0068] (4) Assessment of crop nutrient efficiency and yield potential, see Figure 1

[0069] ① Use PD to evaluate crop nutrient efficiency

[0070] When PD < 0, the nutrient efficiency of the tested variety is lower than that of the control variety;

[0071] When PD = 0, the nutrient efficiency of the tested variety is equal to that of the control variety;

[0072] When PD>0, the nutrient efficiency of the tested variety is higher than that of the control variety.

[0073] ②Polar angle θ 0 Can be used to evaluate the yield potential of crop varieties:

[0074] When 0<θ 0 When the angle is less than 180°, the yield potential of the tested variety is higher than that of the control variety, that is, it is expected to obtain a higher yield than the control variety under normal planting management;

[0075] When 180°<θ 0 When the angle is less than 360°, the yield potential of the tested variety is lower than that of the control variety.

[0076] ③ PD and θ 0 Combined with, comprehensive evaluation of crop yield potential and nutrient efficiency:

[0077] When PD>0 and 45°<θ 0 When the angle is less than 180°, the nutrient efficiency and yield potential of the tested varieties are higher than those of the control varieties;

[0078] When PD>0 and 180°<θ 0 When the temperature is less than 225°, the nutrient efficiency of the tested varieties is higher than that of the control varieties, but the yield potential is lower than that of the control varieties;

[0079] When PD<0 and 0°<θ 0 When the temperature is less than 45°, the nutrient efficiency of the tested varieties is lower than that of the control varieties, but the yield potential is higher than that of the control varieties;

[0080] When PD<0 and 225°<θ 0 When the angle was less than 360°, the nutrient efficiency and yield potential of the tested varieties were lower than those of the control varieties.

[0081] The method provided by the present invention can evaluate the crop nutrient efficiency of macronutrients such as nitrogen, phosphorus, potassium, etc., and is applicable to crops including but not limited to corn, rice, wheat, or melons, fruits, and vegetables.

[0082] The following is an explanation with reference to specific application examples.

[0083] Experimental design: 5 test varieties and 1 control variety, both test varieties and control varieties were set with nitrogen application rate of 0 and 225 kgN / ha, and long-term positioning for nine years. At the physiological maturity period (harvest period), grain yield, grain nitrogen concentration, straw biomass, straw nitrogen concentration were measured, and nitrogen fertilizer partial productivity, agronomic nitrogen fertilizer utilization rate, nitrogen fertilizer recovery rate, nitrogen physiological utilization rate, PD and θ were calculated. 0The conditions of the tested varieties and the control varieties are shown in Table 1. The results of the harvest period determination are shown in Table 2. The calculation results of the relevant evaluation indicators are shown in Table 3.

[0084] Table 1 Variety number, name and breeding years

[0085]

[0086] Table 2 Grain yield, grain nitrogen concentration, straw biomass, and straw nitrogen concentration at physiological maturity

[0087]

[0088]

[0089] Table 3 Partial nitrogen productivity, agronomic nitrogen utilization efficiency, nitrogen recovery efficiency, nitrogen physiological utilization efficiency, PD and θ 0

[0090]

[0091] Correlation analysis showed that the Pearson coefficients of PD and nitrogen fertilizer partial productivity, agronomic nitrogen fertilizer utilization rate, nitrogen fertilizer recovery rate, and nitrogen physiological utilization rate were 0.9887, 0.9999, 0.8570, and 0.9042, respectively, and all reached extremely significant levels, indicating that the projected difference PD can be well used to evaluate crop nutrient efficiency. According to the discrimination criteria provided by the present invention, the nutrient efficiency and yield potential of T1, T2, and T3 are lower than those of the control variety; the nutrient efficiency of T4 is lower than that of the control variety, but the yield potential is higher than that of the control variety; the nutrient efficiency and yield potential of T5 are higher than those of the control variety, so T5 can be used as a potential nutrient-efficient breeding variety.

[0092] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for evaluating crop nutrient efficiency based on polar coordinates, characterized in that: The following steps are involved: A polar coordinate system is established with the yield of the tested variety in the nutrient-deficient plot as the horizontal axis, the yield of the normal plot as the vertical axis, and the average yield of several control varieties as the origin; Based on the established polar coordinate system, the polar coordinates of the tested variety are obtained; The projection difference is calculated with the polar coordinate data of the tested variety, and the nutrient efficiency of the tested variety is evaluated using the projection difference.

2. The method for evaluating crop nutrient efficiency based on polar coordinates according to claim 1, characterized in that: The polar coordinate data of the tested variety include a feature vector with a radius of r and a polar angle of θ0. The polar coordinates of the jth tested variety are: Among them, r j is the radius of the jth tested variety, θ j is the polar angle of the jth tested variety, Tj N0 is the yield of the jth tested variety in the nutrient-deficient plot, Tj N225 is the yield of the jth tested variety in a normal plot, Ci N0 is the yield of the ith control variety in the nutrient-deficient plot, Ci N225 is the yield of the ith control variety in the normal plot, and n is the number of control varieties.

3. The method for evaluating crop nutrient efficiency based on polar coordinates according to claim 2, characterized in that: The calculation formula of the projection difference is: PD=(sinθ0-cosθ0)*r Wherein, PD is the projection difference, θ0 is the polar angle in the polar coordinate data of the tested variety, 0≤θ0<360°, and r is the radius in the polar coordinate data of the tested variety.

4. The method for evaluating crop nutrient efficiency based on polar coordinates according to claim 3, characterized in that: The criteria for evaluating the nutrient efficiency of the tested varieties using the projection difference are: When PD < 0, the nutrient efficiency of the tested variety is lower than that of the control variety; When PD = 0, the nutrient efficiency of the tested variety is equal to that of the control variety; When PD>0, the nutrient efficiency of the tested variety is higher than that of the control variety.

5. The method for evaluating crop nutrient efficiency based on polar coordinates according to claim 2, characterized in that: The polar angle of the polar coordinate data of the tested variety is used as an indicator to evaluate the yield potential of the tested variety.

6. The method for evaluating crop nutrient efficiency based on polar coordinates according to claim 5, characterized in that: The evaluation criteria for evaluating the yield potential of the tested varieties by polar angle are: When 0<θ0<180°, the yield potential of the tested variety is higher than that of the control variety; When 180°<θ0<360°, the yield potential of the tested variety is lower than that of the control variety.

7. The method for evaluating crop nutrient efficiency based on polar coordinates according to claim 2, characterized in that: The polar angle of the polar coordinate data of the tested variety and the projection difference are used as indicators to comprehensively evaluate the nutrient efficiency and yield potential of the tested variety.

8. The method for evaluating crop nutrient efficiency based on polar coordinates according to claim 7, characterized in that: The evaluation criteria for comprehensively evaluating the nutrient efficiency and yield potential of the tested varieties are: When PD>0 and 45°<θ0<180°, the nutrient efficiency and yield potential of the tested varieties were higher than those of the control varieties; When PD>0 and 180°<θ0<225°, the nutrient efficiency of the tested variety is higher than that of the control variety, but the yield potential is lower than that of the control variety; When PD<0 and 0°<θ0<45°, the nutrient efficiency of the tested variety is lower than that of the control variety, but the yield potential is higher than that of the control variety; When PD<0 and 225°<θ0<360°, the nutrient efficiency and yield potential of the tested varieties were lower than those of the control varieties.

9. The method for evaluating crop nutrient efficiency based on polar coordinates according to claim 1, characterized in that: The nutrient efficiency refers to the efficiency of crops in utilizing nitrogen, phosphorus and potassium.

10. The method for evaluating crop nutrient efficiency based on polar coordinates according to claim 1, characterized in that: The crops are selected from corn, wheat, rice, soybean or melon, fruit and vegetable plants.

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