A method for determining, revising, and designing fertilizer formulations for a nitrogen, phosphorus, and potassium nutrient reduction model.

Abstract

This invention provides a method for determining a nitrogen, phosphorus, and potassium nutrient reduction model, comprising the following steps: determining a basic rice fertilization formula; designing experimental treatments; calculating fertilizer application rates; and determining the nitrogen, phosphorus, and potassium nutrient reduction model. This invention also provides a method for designing a rice fertilization formula based on the above-mentioned reduction model, as well as a method for correcting the above-mentioned reduction model. The determination method provided by this invention, for the first time, finds a balance point between the controlled-release fertilizer application ratio, the amount of soil conditioner, and the nitrogen, phosphorus, and potassium nutrient reduction ratio while ensuring no reduction in rice yield, thus guaranteeing the accuracy of the model and truly achieving fertilizer reduction without yield reduction. The method for designing a rice fertilization formula can formulate a fertilizer reduction plan according to actual conditions and local circumstances, designing the ratio of controlled-release fertilizer to ordinary fertilizer and the amount of soil conditioner applied while reducing fertilizer use; the method is simple and easy to operate. The correction method adjusts the model in a timely manner when parameters change, thus ensuring accurate guidance and reference value for actual production.

Description

Technical Field

[0001] This invention relates to the technical field of plant fertilization methods, specifically to a method for determining and modifying a nitrogen, phosphorus, and potassium nutrient reduction model, and a method for designing fertilization formulas. Background Technology

[0002] Rice is one of my country's most important food crops, with a planting area exceeding 400 million mu (approximately 26.7 million hectares), accounting for about 30% of the total grain crop area. Its yield is close to half of the total grain output, and currently, about two-thirds of the population relies on rice as their staple food. Due to the rapid release of fertilizer nutrients and the short duration of their effect, multiple or large-scale fertilizations are necessary to meet the nutritional needs of rice throughout its growth cycle. However, this long-term fertilization pattern leads to a series of problems due to low fertilizer utilization, including declining rice quality, environmental pollution, increased soil acidification, biodiversity loss, and increased production costs. Therefore, research and development of technologies for reducing fertilizer application and synergistic soil improvement has become one of the important pathways for safe rice production and green development.

[0003] Controlled-release fertilizers and soil conditioners offer new ideas and approaches to solving problems such as low fertilizer utilization, declining soil quality, deteriorating rice quality, and environmental pollution. Controlled-release fertilizers synchronize nutrient release times with crop nutrient requirements, thereby improving fertilizer utilization and reducing environmental pollution. Soil conditioners regulate soil acidity, improve soil structure, and enhance soil fertility through the slow release of micronutrients, continuous decomposition of organic matter, and ongoing optimization of the microbial flora. The rational combination and long-term large-scale application of both will undoubtedly yield significant economic and social benefits. However, most existing controlled-release fertilizer technologies focus on solving the problems of single-application fertilization and nitrogen fertilizer reduction, while conditioners mainly focus on addressing undesirable soil properties. Research on how soil conditioners can reduce the application of macronutrients such as nitrogen, phosphorus, and potassium is relatively scarce, and related technologies on optimizing the reduction ratio of nitrogen, phosphorus, and potassium based on the combination of controlled-release fertilizers and soil conditioners are almost nonexistent. Therefore, how to formulate a nitrogen, phosphorus, and potassium nutrient reduction plan based on different application ratios of controlled-release fertilizers and the amount of soil conditioner has become a major problem faced by fertilizer production enterprises and large-scale growers or cooperatives in the fertilization process.

[0004] Currently, all controlled-release fertilizers and soil conditioners for rice on the market are finished products. Rice farmers find it difficult to adjust the formulas according to their specific conditions. Even if manufacturers specify the application rate, precise reduction in fertilizer use is challenging. Furthermore, the relatively high price of existing controlled-release fertilizers poses a significant burden for large-scale rice growers or cooperatives. If, based on relevant models or methods, fertilizer and conditioner formulas could be adjusted in real-time by purchasing raw materials while effectively reducing fertilizer usage, not only could site-specific formulas be designed to improve fertilizer utilization efficiency and soil quality, but input costs could also be significantly reduced, minimizing environmental pollution. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that the existing controlled-release fertilizer technology lacks research on how to reduce the amount of nitrogen, phosphorus and potassium macroelements when applying soil conditioners, and related technologies on how to optimize the reduction ratio of nitrogen, phosphorus and potassium based on controlled-release fertilizer combined with soil conditioners. Thus, the present invention provides a method for determining, modifying and designing a nitrogen, phosphorus and potassium nutrient reduction model.

[0006] Therefore, the present invention adopts the following technical solution:

[0007] This invention provides a method for determining a nitrogen, phosphorus, and potassium nutrient reduction model, comprising the following steps:

[0008] S11: Determine the basic fertilizer formula for rice; specifically, determine it using soil testing and formula fertilization technology.

[0009] S12: Design experimental treatments, using methods such as uniform experimental design and orthogonal experimental design, and design an optimized fertilization treatment as a control;

[0010] S13: Calculate the amount of fertilizer. Based on the amount of conditioner used in the experimental treatment designed in step S12, the ratio of controlled-release fertilizer application, the ratio of nitrogen, phosphorus and potassium nutrient reduction, and the basic fertilizer formula determined in step S11, calculate the corresponding amount of fertilizer.

[0011] S14: Determine the nitrogen, phosphorus and potassium nutrient reduction model. Conduct field planting experiments according to the experimental treatments designed in step S12 and the fertilization amounts obtained in step S13. Statistically calculate the rice yield of each experimental treatment and the optimized fertilization treatment. Then, fit each experimental treatment with a regression model to obtain a mathematical equation. Substitute the rice yield data of the optimized fertilization treatment into the above equation to obtain the nitrogen, phosphorus and potassium nutrient reduction model.

[0012] The nitrogen, phosphorus, and potassium nutrient reduction model includes a phosphorus and potassium nutrient reduction model and a nitrogen nutrient reduction model.

[0013] Further, in step S12, the experimental treatment design includes, without reducing nitrogen nutrient application and with the addition of controlled-release nitrogen fertilizer, using conditioner, phosphorus nutrient, and potassium nutrient as three experimental factors, and using the conditioner dosage and the reduction ratio of phosphorus and potassium nutrient application as experimental levels, employing a uniform experimental design to obtain the first group of experimental treatments, and designing an optimized fertilization treatment as a control; and,

[0014] Without reducing phosphorus and potassium nutrient application, conditioner, controlled-release nitrogen fertilizer, and nitrogen nutrient were used as three experimental factors, and conditioner dosage, controlled-release nitrogen fertilizer application ratio, and nitrogen nutrient reduction ratio were used as experimental levels. The experimental parameters were "3414" and L16(4). 3 ) or L25(5 3The second group of experimental treatments was obtained through orthogonal experimental design, and an optimized fertilization treatment was designed as a control.

[0015] The experimental levels are set according to the experimental design within the range of conditioner dosage, the range of controlled-release nitrogen fertilizer application ratio within the range of controlled-release nitrogen fertilizer application ratio within the range of nitrogen, phosphorus, and potassium nutrient reduction ...

[0016] Step S14 includes conducting a field planting experiment on rice based on the first set of experimental treatments and the optimized fertilization treatment, statistically analyzing the rice yield of each experimental treatment, and then fitting the data on conditioner dosage and phosphorus and potassium nutrient reduction ratios for each experimental treatment with the rice yield data obtained for each experimental treatment using a regression model to obtain a mathematical equation relating conditioner dosage, phosphorus and potassium nutrient reduction ratios, and yield. Substituting the rice yield data of the optimized fertilization treatment into the above equation, a mathematical model of the functional relationship between conditioner dosage and phosphorus and potassium nutrient reduction ratios is obtained, i.e., the phosphorus and potassium nutrient reduction model; and...

[0017] A field planting experiment was conducted on rice based on the second group of experimental treatments. The rice yield of each experimental treatment was statistically analyzed. Then, the data on conditioner dosage, controlled-release urea application ratio, and nitrogen reduction ratio of each experimental treatment were fitted with the yield data obtained from each experimental treatment using a regression model to obtain mathematical equations between conditioner dosage, controlled-release urea application ratio, nitrogen reduction ratio, and rice yield. Substituting the rice yield data of the optimized fertilization treatment into the above equations, a mathematical model of the functional relationship between the nitrogen nutrient reduction ratio and conditioner dosage and controlled-release nitrogen fertilizer application ratio was obtained, namely the nitrogen nutrient reduction model.

[0018] Specifically, the optimized fertilization treatment involves applying fertilizer using soil testing and formula fertilization technology;

[0019] Nitrogen fertilizer is applied in three applications: basal fertilizer, tillering fertilizer, and heading fertilizer. Phosphorus fertilizer and potassium fertilizer are applied as a single basal application.

[0020] In step S11, determining the basic fertilizer formula for rice includes determining the type of rice, which is early rice, medium rice, or late rice.

[0021] The phosphorus and potassium nutrient reduction model includes:

[0022] Model for reduced phosphorus and potassium nutrient application in early rice: T = 0.91P + 2.01K + 7.71; and,

[0023] Model for reducing phosphorus and potassium nutrient application in mid-season or late-season rice: T = 0.88P + 2.05K + 9;

[0024] In the formula, T is the amount of conditioner, P is the reduction ratio of phosphorus nutrient, K represents the reduction ratio of potassium nutrient, P≤65%, K≤50%;

[0025] The nitrogen nutrient reduction model includes:

[0026] Nitrogen nutrient reduction model for early rice: N = (-0.11T) 2 -0.08C 2 +74.75T+55.85C-0.35TC-4847.55) 1 / 2 -(0.2T-0.41C+13.21); and,

[0027] Nitrogen nutrient reduction model for mid-season or late-season rice: N = (-0.13T) 2 -0.2C 2 +47.9T+77.28C-0.21TC-4035) 1 / 2 +(0.032T+0.038C-11.94);

[0028] In the formula, N is the nitrogen nutrient reduction ratio, T is the conditioner dosage, C is the controlled-release nitrogen fertilizer application ratio, 40≤T≤250kg / mu, 20%≤C≤85%.

[0029] This invention also provides a method for designing rice fertilizer formulas, comprising the following steps:

[0030] S21: Determine the basic fertilizer formula for rice;

[0031] S22: Based on the cost-effectiveness of phosphorus and potassium fertilizers and local soil and climate conditions, the reduction ratio of phosphorus and potassium fertilizers is set, and the amount of conditioner is calculated through the phosphorus and potassium nutrient reduction model.

[0032] S23: Set the application ratio of controlled-release fertilizer based on the cost-effectiveness of controlled-release fertilizer and local soil and climate conditions. Calculate the nitrogen nutrient reduction ratio using the nitrogen nutrient reduction model and the amount of conditioner determined in step S22.

[0033] S24: Based on the basic formula determined in step S21, the reduction ratio of phosphorus and potassium nutrients set in step S22, the determined amount of conditioner, and the controlled-release nitrogen fertilizer application ratio and the determined nitrogen nutrient reduction ratio set in step S23, the rice fertilization formula is calculated.

[0034] The reduction model is obtained by the determination method described above.

[0035] Furthermore, the controlled-release nitrogen fertilizer is resin-coated urea;

[0036] The basic rice fertilization formula includes a basic application formula for early rice and a basic application formula for late or medium-season rice.

[0037] The basic application formula for early rice is as follows: nitrogen application rate is 10-15 kg / mu (N); phosphorus application rate is 5-8 kg / mu (P2O5); and potassium application rate is 8-12 kg / mu (K2O).

[0038] The basic application formula for late-season or mid-season rice is as follows: nitrogen application rate is 12-18 kg / mu (based on N); phosphorus application rate is 5-8 kg / mu (based on P2O5); and potassium application rate is 8-12 kg / mu (based on K2O).

[0039] The controlled-release nitrogen fertilizer used for early rice has a controlled-release period of 50-75 days;

[0040] The controlled-release nitrogen fertilizer used for late-season or mid-season rice has a controlled-release period of 70-105 days.

[0041] This invention also provides a method for correcting a nitrogen, phosphorus, and potassium nutrient reduction model, which is obtained by the above-described method and includes the following steps:

[0042] S31: Determine the basic fertilizer formula for rice;

[0043] S32: Based on the basic formula for rice fertilization and the nutritional requirements of rice, set up optimized fertilization treatment, one-time fertilization treatment, and no fertilization treatment;

[0044] S33: Conduct field planting trials and statistically analyze the yields of optimized fertilization treatment, single fertilization treatment, and no fertilization treatment during model correction.

[0045] S34: Substitute the yield data of the optimized fertilization treatment, the yield of the single fertilization treatment, the yield of the no-fertilization treatment during model correction, and the yield data of the no-fertilization treatment during model determination obtained in step S33 into the correction equation to obtain the corrected model of the nitrogen, phosphorus and potassium nutrient reduction model.

[0046] The corrected equation is:

[0047] The corrected equation for the phosphorus and potassium nutrient reduction model in early rice is: T = 0.91P + 2.01K + 4.4(Y - 458.25 + (Y1 - Y2)), where T represents the amount of conditioner, P represents the proportion of phosphorus reduction (P ≤ 65%), K represents the proportion of potassium reduction (K ≤ 50%), Y represents the yield data of the optimized fertilization treatment, Y1 represents the yield of the no-fertilization treatment when the model was determined, and Y2 represents the yield of the no-fertilization treatment when the model was corrected.

[0048] The corrected equation for the phosphorus and potassium nutrient reduction model in late-season or mid-season rice is: T = 0.88P + 2.05K + 3.72(Y - 548.58 + (Y1 - Y2));

[0049] Corrected equation for early rice nitrogen nutrient reduction model: N=(-0.11T) 2 -0.08C 2 +74.75T+55.85C-0.35T C-75.41(Y-Y0)+174.49) 1 / 2 -(0.2T-0.41C+13.21), where N represents the nitrogen reduction ratio, T represents the conditioner dosage, C represents the controlled-release fertilizer application ratio, Y represents the yield data of the optimized fertilization treatment, and Y0 represents the yield of the single fertilization treatment.

[0050] Corrected equation for nitrogen nutrient reduction model in late-season or mid-season rice: N = (-0.13T) 2 -0.2C 2 +47.9T+77.28C-0.21TC-51.04(Y-Y0)+142.56) 1 / 2 +(0.032T+0.038C-11.94).

[0051] The correction method described above is applicable when the yield obtained by the optimized fertilization treatment during model correction differs from the yield obtained by the optimized fertilization treatment when the model was determined by ≤10%. If the difference is ≥10%, the nitrogen, phosphorus and potassium nutrient reduction model needs to be redefined according to claims 1-5.

[0052] The technical solution of this invention has the following advantages:

[0053] (1) The method for determining the nitrogen, phosphorus, and potassium nutrient reduction model provided by the present invention, wherein the phosphorus and potassium nutrient reduction model is obtained through uniform experimental design, which significantly reduces the number of experiments while fully considering the phosphorus and potassium reduction gradient; the nitrogen nutrient reduction model is obtained by using "3414" and L16(4 3 ) or L25(5 3The orthogonal experimental design not only quantified the interaction effect between conditioner and controlled-release nitrogen fertilizer, but also effectively reduced the number of experiments. Without reducing rice yield, the balance point between the controlled-release fertilizer application ratio, conditioner dosage, and nitrogen, phosphorus, and potassium nutrient reduction ratio was cleverly found by incorporating the yield of optimized fertilization treatments into the regression model. A clear mathematical relationship model between them was also proposed. This has significant reference value for the efficient application of controlled-release fertilizers and conditioners in field crops and for the development of the entire controlled-release fertilizer and conditioner industry. Furthermore, in this invention, the preferred conditioner dosage range is 0-250 kg / mu, the controlled-release nitrogen fertilizer application ratio range is 20%-85%, and the nitrogen, phosphorus, and potassium nutrient reduction ratios range are 0%-50%, 0%-65%, and 0%-50%, respectively. This setting is because if the proportion of controlled-release fertilizer is too low, there is basically no room for reduction. If the proportion of nitrogen, phosphorus, and potassium nutrients reduced is too high, the nutritional needs of rice cannot be met. Therefore, this range takes into account both the proportion of controlled-release fertilizer and the nutritional needs of rice, so as to ensure the accuracy of the model and truly achieve the goal of reducing fertilizer use without reducing yield.

[0054] (2) The present invention provides a method for designing rice fertilizer formulations based on a nitrogen, phosphorus, and potassium nutrient reduction model. According to this method, rice producers or large-scale grain growers can easily and quickly adjust the amount of controlled-release fertilizer and soil conditioner applied. They can formulate reduction plans according to their actual conditions and local circumstances, and rationally design the ratio of controlled-release fertilizer to ordinary fertilizer and the amount of soil conditioner applied while reducing fertilizer application. The method is simple and easy to operate. This method not only allows for the design of formulations tailored to local conditions, but also improves fertilizer utilization, improves paddy field soil, significantly reduces input costs, and reduces environmental pollution, making it particularly suitable for long-term continuous use. Furthermore, this method provides excellent guidance and reference for fertilizer producers. Fertilizer producers can adjust their formulations according to this method, producing specialized fertilizers suitable for different climatic conditions and soil fertility levels, and effectively reducing production costs.

[0055] (3) The soil conditioner used in this method is a silicon-calcium-potassium-magnesium fertilizer that meets the national standard (GBT 36207-2018) or a conditioner product produced according to the invention patent (ZL201510556136.5) or a soil conditioner product containing nutrients such as calcium, magnesium, phosphorus, potassium, and silicon. This is because soil conditioner products containing nutrients such as calcium, magnesium, phosphorus, potassium, and silicon can not only effectively replenish trace elements in the soil and significantly improve soil acidity, but also, when the dosage is greater than 50 kg / mu, can have an interactive effect with controlled-release nitrogen fertilizer to significantly reduce the amount of nitrogen fertilizer used.

[0056] (4) The present invention also provides a method for correcting the nitrogen, phosphorus and potassium nutrient reduction model. This method can adjust the reduction model in a timely manner when parameters change (such as soil fertility, climate conditions, cultivation management techniques, etc.), thereby ensuring accurate guidance and reference value for actual production. Moreover, the correction method of this model is very simple. It only requires designing three treatments: no fertilization, one-time fertilization and optimized fertilization to correct the model. Detailed Implementation

[0057] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] The conditioning agent used in the examples was silicon-calcium-potassium-magnesium fertilizer, produced by Kingenta Ecological Engineering Group Co., Ltd.; the conventional nitrogen fertilizer was urea; the controlled-release nitrogen fertilizer was resin-coated urea, produced by Kingenta Ecological Engineering Group Co., Ltd.; the phosphate fertilizer was produced by Yunnan Yuntianhua Co., Ltd.; and the potash fertilizer was produced by Sinochem Group Co., Ltd.

[0059] Example 1

[0060] This embodiment provides a method for determining a nitrogen, phosphorus, and potassium nutrient reduction model, including the following steps:

[0061] S11, determine the basic formula for rice fertilization;

[0062] Specifically, it should be determined according to the "Technical Specifications for Soil Testing and Fertilizer Recommendation (2011 Revised Edition)":

[0063] For early rice, the general application rate is 10-15 kg / mu of pure nitrogen (N), 5-8 kg / mu of phosphorus (P2O5), and 8-12 kg / mu of pure potassium (K2O). For mid-season or late-season rice, the general application rate is 12-18 kg / mu of nitrogen (N), 5-8 kg / mu of phosphorus (P2O5), and 8-12 kg / mu of potassium (K2O). The controlled-release nitrogen fertilizer used for early rice has a controlled-release period of 50-75 days, while that used for late-season rice is 70-105 days. In this example, the basic formula for early rice is N: 12 kg / mu; P2O5: 6 kg / mu; K2O: 10 kg / mu, and the basic formula for late-season rice is N: 14 kg / mu; P2O5: 6 kg / mu; K2O: 10 kg / mu.

[0064] In this embodiment, the early rice variety was Xinrongyou No. 5, and the late rice variety was Wuyou Huazhan. The test site was Fenglong Village, Heshi Town, Taihe County, Jiangxi Province.

[0065] S12, Design of experimental treatment;

[0066] Specifically, (1) Conditioner, phosphorus nutrient and potassium nutrient were used as three experimental factors, and the amount of conditioner, the reduction ratio of phosphorus nutrient and the reduction ratio of potassium nutrient were used as experimental levels. The first experimental treatment was obtained by uniform design, and the optimized fertilization treatment was designed as a control.

[0067] Within the range of conditioner dosage, a series of dosage levels are set according to the uniform design requirements and an arithmetic sequence. Within the range of phosphorus and potassium nutrient reduction ratios, a series of reduction ratios are set according to the uniform design requirements and an arithmetic sequence. The conditioner dosage range is 0-250 kg / mu, and the phosphorus and potassium nutrient reduction ratio ranges are 0-65% and 0-50%, respectively.

[0068] Here, the determination of soil conditioner dosage and the reduction ratio of phosphorus and potassium nutrients is only illustrative: according to U8(8 3 The uniform design requires setting the conditioner dosage at eight levels: 0, 30, 60, 90, 120, 150, 180, and 210 kg / mu, based on an arithmetic sequence. The phosphorus nutrient reduction ratios are set at eight levels: 0%, 9%, 18%, 27%, 36%, 45%, 54%, and 63%. Similarly, the potassium nutrient reduction ratios are set at eight levels: 0%, 7%, 14%, 21%, 28%, 35%, 42%, and 49%. This is based on U8(8) 3 The first experimental treatment was obtained by uniform design table. The optimized fertilization treatment was designed according to the normal application levels of phosphorus and potassium nutrients without conditioner.

[0069] (2) Conditioner, controlled-release nitrogen fertilizer and nitrogen nutrients were used as three experimental factors. Conditioner dosage, controlled-release nitrogen fertilizer application ratio and nitrogen nutrient reduction ratio were used as experimental levels. The second experimental treatment was obtained by using the “3414” experimental design, and an optimized fertilization treatment was designed as a control.

[0070] Within the range of conditioner dosage, a series of dosage levels are set according to the arithmetic progression of the "3414" experimental design requirements. Within the range of controlled-release nitrogen fertilizer application ratio, a series of application ratios are set according to the arithmetic progression of the "3414" experimental design requirements. Within the range of nitrogen nutrient reduction ratio, a series of reduction ratios are set according to the arithmetic progression of the "3414" experimental design requirements. The conditioner dosage range is 0-250 kg / mu, the controlled-release nitrogen fertilizer application ratio range is 0%-85%, and the nitrogen nutrient reduction ratio range is 0%-50%.

[0071] Here, the determination of soil conditioner dosage, controlled-release fertilizer application ratio, and nitrogen nutrient reduction ratio is only illustrated: According to the "3414" experimental design requirements, the conditioner dosage is set to 0, 50, 100, and 150 kg / mu at four levels according to an arithmetic sequence; the controlled-release nitrogen fertilizer application ratio is set to 0%, 25%, 50%, and 75% at four levels; and the nitrogen nutrient reduction ratio is set to 0%, 15%, 30%, and 45% at four levels. The second experimental treatment is obtained according to the "3414" orthogonal experimental design table. The optimized fertilization treatment is designed according to the levels of no controlled-release fertilizer and normal nitrogen nutrient application.

[0072] S13, calculate the amount of fertilizer. Based on the amount of conditioner used in the experimental treatment designed in step S12, the ratio of controlled-release fertilizer application, the ratio of nitrogen, phosphorus and potassium nutrient reduction, and the basic fertilizer formula determined in step S11, calculate the corresponding amount of fertilizer.

[0073] S14: Determine the nitrogen, phosphorus and potassium nutrient reduction model. Conduct field planting experiments according to the experimental treatments designed in step S12 and the fertilization amounts obtained in step S13. Statistically calculate the rice yield of each experimental treatment and the optimized fertilization treatment. Then, fit each experimental treatment with a regression model to obtain a mathematical equation. Substitute the rice yield data of the optimized fertilization treatment into the above equation to obtain the nitrogen, phosphorus and potassium nutrient reduction model.

[0074] Specifically, including:

[0075] (1) Phosphorus and potassium nutrient reduction model:

[0076] Conditioner, phosphorus, and potassium were used as three experimental factors. Eight dosage levels and eight reduction ratio levels for S12 were set as experimental levels. The U8(8) method was employed. 3 The uniform design yielded 8 experimental treatments, forming the first group. An optimized fertilization treatment (CK) and a no-fertilization treatment were also included, resulting in a total of 10 experimental treatments. For each treatment, nitrogen fertilizer was applied three times: before transplanting, at the tillering stage, and at the ear differentiation stage. Phosphorus and potassium fertilizers were applied once as basal fertilizer. Then, a plot-based field trial was conducted on all 10 treatments, with each plot measuring 20-30 m². 2 A randomized block design was used, with each treatment replicated three times. Yields were calculated after rice maturity. The results are shown in Table 1.

[0077] Table 1 shows the results of a field planting trial with conditioner, phosphorus, and potassium as the three experimental factors.

[0078]

[0079]

[0080] For each experimental treatment, yield data and the data on conditioner dosage and nutrient reduction ratio under each treatment were fitted using a ternary linear regression model to obtain mathematical equations relating conditioner dosage, phosphorus nutrient reduction ratio, potassium nutrient reduction ratio, and yield. Specifically, the mathematical equation for early rice is: Y = -0.207P - 0.456K + 0.227T + 458.25 (where Y is rice yield, P is the phosphorus nutrient reduction ratio, K is the potassium nutrient reduction ratio, and T is conditioner dosage); the mathematical equation for late rice is: Y = -0.238P - 0.552K + 0.269T + 548.58. Finally, the yield data of early rice (460 kg / mu) and late rice (550 kg / mu) obtained from optimized fertilization (i.e., the optimized fertilization treatment) were substituted into the above mathematical equations to calculate the mathematical models relating conditioner dosage to phosphorus and potassium nutrient reduction ratios. The specific results are shown below:

[0081] Model for reducing phosphorus and potassium nutrient application in early rice: T = 0.91P + 2.01K + 7.71(R) 2 =0.98, P=0.00084);

[0082] Model for reducing phosphorus and potassium nutrient application in mid-season or late-season rice: T = 0.88P + 2.05K + 9(R) 2 =0.90, P=0.019);

[0083] In the formula, T is the amount of conditioner, P is the reduction ratio of phosphorus nutrient, K represents the reduction ratio of potassium nutrient, P≤65%, K≤50%.

[0084] (2) Nitrogen nutrient reduction model:

[0085] Conditioner, controlled-release nitrogen fertilizer, and nitrogen nutrients were used as three experimental factors. A "3414" experimental design was adopted, using four conditioner dosage levels, four controlled-release urea application ratio levels, and four nitrogen nutrient reduction ratio levels set in S12 as experimental levels. Fourteen experimental treatments were obtained using the "3414" design, with an optimized fertilization treatment as a control, for a total of 15 treatments. In the optimized fertilization treatment, nitrogen fertilizer was applied three times: before transplanting, at the tillering stage, and at the ear differentiation stage; phosphorus and potassium fertilizers were applied as a single basal application. All other treatments were applied as a single fertilization. Then, field trials were conducted on the 15 treatments, with each plot area controlled at 20-30 m². 2 A randomized block design was used, with each treatment replicated three times. Yields were calculated after rice maturity, and specific yield data are shown in Table 2.

[0086] Table 2 shows the results of field planting trials using conditioners, controlled-release nitrogen fertilizer, and nitrogen nutrients as experimental factors.

[0087]

[0088] For each experimental treatment, yield data were fitted with data on conditioner dosage, controlled-release urea application ratio, and nitrogen nutrient reduction ratio under each treatment using a ternary quadratic regression model. This yielded mathematical equations relating conditioner dosage, controlled-release urea application ratio, and nitrogen nutrient reduction ratio to yield. Specifically, the mathematical equation for early rice is: Y = -0.002T 2 -0.0033C 2 -0.013N 2 +0.92T+0.88C-0.35N-0.0025TC-0.0053TN+0.011CN+393.33 (where Y is rice yield, N is the nitrogen nutrient reduction ratio, T is the conditioner dosage, and C is the controlled-release nitrogen fertilizer application ratio); Mathematical equation for late-season rice: Y=-0.0026T 2 -0.0039C 2 -0.019N 2 +0.95T+1.53C-0.47N-0.0042TC+0.0012TN+0.0015CN+469.16, and finally, substituting the early rice yield data of 460 kg / mu and the late rice yield data of 550 kg / mu obtained from the optimized fertilization treatment into the above equation, we can calculate the mathematical model of nitrogen nutrient reduction ratio, conditioner dosage, and controlled-release urea application ratio:

[0089] Nitrogen nutrient reduction model for early rice: N = (-0.11T) 2 -0.08C 2 +74.75T+55.85C-0.35TC-4847.55) 1 / 2 -(0.2T-0.41C+13.21)(R 2 =0.98, P=0.0046);

[0090] Nitrogen nutrient reduction model for late-season or mid-season rice: N = (-0.13T) 2 -0.2C 2 +47.9T+77.28C-0.21TC-4035) 1 / 2 +(0.032T+0.038C-11.94)(R 2 =0.98, P=0.0051);

[0091] In the formula, N is the nitrogen nutrient reduction ratio, T is the conditioner dosage, C is the controlled-release nitrogen fertilizer application ratio, 40≤T≤250kg / mu, 20%≤C≤85%.

[0092] Example 2

[0093] This embodiment provides a method for designing rice fertilization formulas using the nitrogen, phosphorus, and potassium nutrient reduction model obtained in Example 1.

[0094] S21, Determine the basic fertilizer formula for rice; specifically, determine it according to the "Technical Specification for Soil Testing and Fertilizer Formula (2011 Revised Edition)";

[0095] Similar to Example 1, the basic formula for early rice is N: 12 kg / mu; P2O5: 6 kg / mu; K2O: 10 kg / mu, and the basic formula for late rice is N: 14 kg / mu; P2O5: 6 kg / mu; K2O: 10 kg / mu.

[0096] S22 sets the reduction ratio of phosphorus and potassium fertilizers based on their cost-effectiveness and local soil and climate conditions, and calculates the amount of conditioner to be used through the phosphorus and potassium nutrient reduction model.

[0097] Specifically, the dosage of conditioner is determined based on the reduction ratio of phosphorus and potassium nutrients: when the reduction ratio of phosphorus and potassium is ≥0, such as setting the reduction ratio of phosphorus nutrient to 50% and the reduction ratio of potassium nutrient to 35% for early rice and late rice, the dosage of conditioner for early rice is 123 kg / mu according to the calculation results of the phosphorus and potassium nutrient reduction model T = 0.91P + 2.01K + 7.71; and the dosage of conditioner for late rice is 125 kg / mu according to the calculation results of the phosphorus and potassium nutrient reduction model T = 0.88P + 2.05K + 9.

[0098] S23: Based on the cost-effectiveness of controlled-release fertilizer and local soil and climate conditions, set the application ratio of controlled-release fertilizer, and calculate the nitrogen nutrient reduction ratio through the nitrogen nutrient reduction model and the amount of conditioner determined in step S22.

[0099] Specifically, the nitrogen nutrient reduction ratio is determined based on the conditioner dosage and the controlled-release urea application ratio. By setting the controlled-release urea application ratio and the conditioner dosage determined in step S2, such as setting the controlled-release urea application ratio for early rice and late rice to 50%, and the conditioner dosage to 123 and 125 kg / mu respectively, the nitrogen nutrient reduction model for early rice is applied: N = (-0.11T) / mu. 2 -0.08C 2 +74.75T+55.85C-0.35TC-4847.55) 1 / 2 The calculation result of -(0.2T-0.41C+13.21) shows that the nitrogen nutrient reduction ratio for early rice is 39%; the nitrogen nutrient reduction model for late rice is N=(-0.13T) / (0.2T-0.41C+13.21). 2 -0.2C 2 +47.9T+77.28C-0.21TC-4035) 1 / 2 The calculation result of +(0.032T+0.038C-11.94) shows that the nitrogen nutrient application reduction ratio for late rice is 38%.

[0100] S24: Based on the basic formula determined in step S21, the reduction ratio of phosphorus and potassium nutrients set in step S22, the determined amount of conditioner, and the controlled-release nitrogen fertilizer application ratio and the determined nitrogen nutrient reduction ratio set in step S23, the rice fertilization formula is calculated.

[0101] Specifically, based on the phosphorus and potassium nutrient reduction models and the nitrogen nutrient reduction models, the nitrogen nutrient reduction ratios for early rice with controlled-release urea at 30%-70% and conditioner at 46-134 kg / mu are 3%-47%, 20%-50%, and 10%-40%; and for late rice with controlled-release urea at 30%-70% and conditioner at 47-135 kg / mu, the nitrogen nutrient reduction ratios are 4%-45%, 20%-50%, and 10%-40%. Calculations showed that the reduced application rates for nitrogen (0.36-5.67 kg / mu), phosphorus (1.2-3 kg / mu), and potassium (1-4 kg / mu) were calculated for early rice; and for late rice, the reduced rates were 0.56-6.32 kg / mu, 1.2-3 kg / mu, and 1-4 kg / mu. This resulted in actual application rates of 6.33-11.64 kg / mu for nitrogen (N), 3-4.8 kg / mu for phosphorus (P2O5), and 6-9 kg / mu for potassium (K2O) for early rice; and 7.68-13.44 kg / mu for nitrogen (N), 3-4.8 kg / mu for phosphorus (P2O5), and 6-9 kg / mu for potassium (K2O) for late rice. Small-plot field trials were conducted, with each plot controlled at 20-30 m². 2 The study employed a randomized block design with three replicates for each experimental case. Specific fertilizer formulations are shown in Tables 3 and 4 below. The control (CK) represents the optimized fertilization treatment: early rice received 12 kg / mu of nitrogen (N), 6 kg / mu of phosphorus (P2O5), and 10 kg / mu of potassium (K2O); late rice received 14 kg / mu of nitrogen (N), 6 kg / mu of phosphorus (P2O5), and 10 kg / mu of potassium (K2O). In the optimized treatment, nitrogen fertilizer was applied three times: before transplanting, at the tillering stage, and at the panicle differentiation stage. Phosphorus and potassium fertilizers were applied once as basal fertilizer, and the rest were applied once.

[0102] Table 3 Fertilizer formula for early rice

[0103]

[0104]

[0105] Table 4 Fertilizer Formula for Late Rice

[0106]

[0107]

[0108] The method provided by this invention can also be used to guide fertilizer production enterprises to produce fertilizers of different specifications. Fertilizer production enterprises can adjust the formula directly according to the user's needs, referring to the determined reduction model, and directly produce fertilizers that farmers can directly apply in accordance with the above-mentioned ratio requirements.

[0109] Currently, most fertilizer manufacturers have mastered the production technology and methods for ordinary compound fertilizers specifically for early and late rice. If coated controlled-release urea and conditioners are added to the special compound fertilizer, it is only necessary to adjust the nitrogen, phosphorus, and potassium nutrient elements according to the nitrogen nutrient reduction model and the phosphorus and potassium nutrient reduction model based on the original formula. For example, the formulas for ordinary compound fertilizers for early rice and late rice are 24-14-18 (N-P2O5-K2O) and 28-14-18, respectively. The reduction ratios for phosphorus and potassium nutrients are set at 50% and 30%, respectively. Based on the early rice phosphorus and potassium nutrient reduction model T = 0.91P + 2.01K + 7.71 and the late rice phosphorus and potassium nutrient reduction model T = 0.88P + 2.05K + 9, the calculation results show that the conditioner dosage for early rice is 114 kg / mu, and for late rice it is 115 kg / mu. Then, the mixing ratio of coated controlled-release urea is set at 50%, according to N = (-0.11T... 2 -0.08C 2 +74.75T+55.85C-0.35TC-4847.55) 1 / 2 The calculation result of -(0.2T-0.41C+13.21) shows that the nitrogen nutrient reduction ratio for early rice is 38%. According to N=(-0.13T) 2 -0.2C 2 +47.9T+77.28C-0.21TC-4035) 1 / 2 The calculation result (+(0.032T+0.038C-11.94)) shows that the nitrogen nutrient reduction ratio for late-season rice is 37%. Therefore, the formulas for early-season and late-season rice can be adjusted to 15-7-13 and 18-7-13, respectively. Enterprises can produce fertilizers according to these formulas, and by mixing in a conditioner at a dosage of 114 kg / mu for early-season rice and 115 kg / mu for late-season rice, not only will production costs be reduced, but the input of nitrogen, phosphorus, and potassium nutrients will also be significantly reduced, greatly improving fertilizer utilization.

[0110] Example 3

[0111] This embodiment also provides a method for correcting the nitrogen, phosphorus, and potassium nutrient reduction model obtained in Example 1, including the following steps:

[0112] S31: Determine the basic fertilizer formula for rice;

[0113] S32: Based on the basic formula for rice fertilization and the nutritional requirements of rice, set up optimized fertilization treatment, one-time fertilization treatment, and no fertilization treatment;

[0114] S33: Conduct field planting trials, measure yield at rice maturity, and statistically analyze the yield of the optimized fertilization treatment (Y), the yield of the single fertilization treatment (Y0), and the yield of the no fertilization treatment (Y2).

[0115] Specifically, two experimental fields with different fertility were selected. Experimental field I was located in Jinnan Village, Jinnan Town, Shanggao County, Jiangxi Province. The field area was 2 mu (approximately 0.33 hectares), the soil texture was loam, and the organic matter content was 4.66%, which is considered a relatively fertile field. Experimental field II was located in Gaoxing Village, Gaoxing Town, Xingguo County, Jiangxi Province. The field area was 1.6 mu (approximately 0.08 hectares), the soil texture was sandy loam, and the organic matter content was 2.31%, which is considered a relatively fertile field. Experiments were conducted on early and late rice in both Experimental Field I and Experimental Field II. Each rice season included three treatments: optimized fertilization, single-application fertilization, and no fertilization. The optimized fertilization and single-application fertilization treatments applied 14 kg / mu of nitrogen, 6 kg / mu of phosphorus (P2O5), and 10 kg / mu of potassium (K2O). In the optimized fertilization treatment, nitrogen was applied three times: before transplanting, at the tillering stage, and at the young panicle differentiation stage, in a ratio of 2:1:1. Phosphorus and potassium were applied once as basal fertilizer before transplanting. In the single-application fertilization treatment, nitrogen, phosphorus, and potassium were applied once as basal fertilizer before transplanting. Each treatment had three replicates arranged in a randomized block design. Routine field management followed the fertilization practices of local farmers.

[0116] Yields were measured at the rice maturity stage. The yields of the optimized fertilization treatment (Y), the single fertilization treatment (Y0), and the no fertilization treatment (Y2) were statistically analyzed. The specific data are shown in Table 5 below.

[0117] Table 5. Technical parameters involved in model correction

[0118]

[0119] S34: Substitute the yields (Y) of the statistically optimized fertilization treatment, the yield of the single fertilization treatment (Y0), and the yield of the no-fertilization treatment (Y2) obtained in step S33, and the yield of the no-fertilization treatment (Y1) when the model was determined, into the following correction equation to obtain the corrected model of the nitrogen, phosphorus, and potassium nutrient reduction model.

[0120] The corrected equation is:

[0121] Corrected equation for reduced P and potassium nutrient application in early rice: T = 0.91P + 2.01K + 4.4(Y - 458.25 + (Y1 - Y2))(R 2 =0.98, P=0.00084), the corrected equation for reducing P and potassium nutrient application in late-season or mid-season rice is: T=0.88P+2.05K+3.72(Y-548.58+(Y1-Y2))(R2 =0.90, P=0.019)

[0122] Corrected equation for nitrogen nutrient reduction in early rice: N = (-0.11T) 2 -0.08C 2 +74.75T+55.85C-0.35TC-75.41(Y-Y0)+174.49) 1 / 2 -(0.2T-0.41C+13.21)(R 2 =0.98, P=0.0046),

[0123] Corrected equation for nitrogen nutrient reduction in late-season rice: N = (-0.13T) 2 -0.2C 2 +47.9T+77.28C-0.21TC-51.04(Y-Y0)+142.56) 1 / 2 +(0.032T+0.038C-11.94)(R 2 =0.98, P=0.0051).

[0124] Specifically, by substituting the yield data of early rice and late rice obtained from experimental field I and experimental field II, and the yield data (Y1) of the no-fertilizer treatment at the time of model determination, into the above correction equation, the corrected model is obtained as follows:

[0125] The modified model obtained from Experimental Field I:

[0126] Corrected model for reduced phosphorus and potassium nutrient application in early rice: T = 0.91P + 2.01K - 27.5(R) 2 =0.98, P=0.00084),

[0127] Corrected model for reduced phosphorus and potassium nutrient application in late-season rice: T = 0.88P + 2.05K - 20.76(R) 2 =0.90, P=0.019)

[0128] Corrected model for nitrogen nutrient reduction in early rice: N = (-0.11T) 2 -0.08C 2 +74.75T+55.85C-0.35TC-4400.63) 1 / 2 -(0.2T-0.41C+13.21)(R 2 =0.98, P=0.0046),

[0129] Corrected model for nitrogen nutrient reduction in late-season rice: N = (-0.13T) 2 -0.2C 2 +47.9T+77.28C-0.21TC-3737.24) 1 / 2+(0.032T+0.038C-11.94)(R 2 =0.98, P=0.0051)

[0130] The corrected model obtained from Experimental Field II:

[0131] Corrected model for reduced phosphorus and potassium nutrient application in early rice: T = 0.91P + 2.01K + 34.1(R) 2 =0.98, P=0.00084);

[0132] Corrected model for reduced phosphorus and potassium nutrient application in late-season rice: T = 0.88P + 2.05K + 23.88(R) 2 =0.90, P=0.019);

[0133] Corrected model for nitrogen nutrient reduction in early rice: N = (-0.11T) 2 -0.08C 2 +74.75T+55.85C-0.35TC-5305.55) 1 / 2 -(0.2T-0.41C+13.21)(R 2 =0.98, P=0.0046);

[0134] Corrected model for nitrogen nutrient reduction in late-season rice: N = (-0.13T) 2 -0.2C 2 +47.9T+77.28C-0.21TC-4605.09) 1 / 2 +(0.032T+0.038C-11.94)(R 2 =0.98, P=0.0051).

[0135] Example 4

[0136] After the rice in the experimental example of Example 2 matured, the yield was calculated. At the same time, plant samples were collected to determine the nitrogen, phosphorus, and potassium nutrient content in order to calculate the nitrogen, phosphorus, and potassium nutrient utilization rate. The specific rice yield and nitrogen, phosphorus, and potassium nutrient utilization rate data are shown in Tables 6 and 7. The economic benefits were also calculated, and the specific results are shown in Tables 8 and 9.

[0137] Table 6. Yield and nutrient utilization rate of early rice

[0138]

[0139]

[0140] Table 7. Yield and nutrient utilization rate of late-season rice

[0141]

[0142] Table 8. Calculation of Economic Benefits of Early Rice

[0143]

[0144]

[0145] Table 9. Calculation of Economic Benefits of Late Rice

[0146]

[0147]

[0148] As can be seen from the data in Tables 6-9 above, the fertilization scheme determined by this invention can not only reduce fertilizer use without reducing yield, but also improve the utilization rate of nitrogen, phosphorus and potassium nutrients, reduce enterprise production costs, and increase the economic benefits of rice.

[0149] Example 5

[0150] The modified method of Example 3 was verified, and the modified model obtained in Example 3 was used to design rice fertilizer formulas. The design method was the same as in Example 2, and the results are shown in Tables 10-13:

[0151] Table 10 Fertilizer formula and yield of early rice in Experimental Field I

[0152]

[0153] Table 11 Fertilizer formula and yield of late-season rice in Experimental Field I

[0154]

[0155] Table 12 Fertilizer formula and yield of early rice in Experimental Field II

[0156]

[0157] Table 12 Fertilizer formula and yield of early rice in Experimental Field II

[0158]

[0159] Table 13 Fertilizer formula and yield of late-season rice in Experimental Field II

[0160]

[0161] As can be seen from Tables 10-13 above, the rice fertilization formula designed according to the modified model obtained by the modification method of Embodiment 3 of the present invention can reduce fertilizer use without reducing yield.

[0162] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for determining a nitrogen, phosphorus, and potassium nutrient reduction model, characterized in that, Includes the following steps: S11: Determine the basic fertilizer formula for rice; S12: Design experimental treatments. Uniform experimental design and orthogonal experimental design methods were used to design experimental treatments, and an optimized fertilization treatment was designed as a control. S13: Calculate the amount of fertilizer. Based on the amount of conditioner used in the experimental treatment designed in step S12, the ratio of controlled-release fertilizer application, the ratio of nitrogen, phosphorus and potassium nutrient reduction, and the basic fertilizer formula determined in step S11, calculate the corresponding amount of fertilizer. S14: Determine the nitrogen, phosphorus and potassium nutrient reduction model. Conduct field planting experiments according to the experimental treatments designed in step S12 and the fertilization amounts obtained in step S13. Statistically calculate the rice yield of each experimental treatment and the optimized fertilization treatment. Then, fit each experimental treatment with a regression model to obtain a mathematical equation. Substitute the rice yield data of the optimized fertilization treatment into the above equation to obtain the nitrogen, phosphorus and potassium nutrient reduction model. The nitrogen, phosphorus, and potassium nutrient reduction model includes a phosphorus and potassium nutrient reduction model and a nitrogen nutrient reduction model; The phosphorus and potassium nutrient reduction model includes: Model for reduced phosphorus and potassium nutrient application in early rice: T = 0.91P + 2.01K + 7.71; and, Model for reducing phosphorus and potassium nutrient application in mid-season or late-season rice: T = 0.88P + 2.05K + 9; In the formula, T represents the dosage of conditioner, P represents the reduction ratio of phosphorus nutrient application, K represents the reduction ratio of potassium nutrient application, P≤65%, K≤50%; The nitrogen nutrient reduction model includes: Nitrogen nutrient reduction model for early rice: N = (-0.11 T) 2 -0.08C 2 +74.75 T +55.85C-0.35 T C-4847.55) 1 / 2 -(0.2 T -0.41C+13.21); and, Nitrogen nutrient reduction model for mid-season or late-season rice: N = (-0.13T) 2 -0.2C 2 +47.9 T +77.28C-0.21 TC-4035) 1 / 2 +(0.032 T +0.038C-11.94); In the formula, N is the nitrogen nutrient reduction ratio, T is the conditioner dosage, C is the controlled-release nitrogen fertilizer application ratio, 40 ≤ T ≤ 250 kg / mu, and 20% ≤ C ≤ 85%.

2. The determination method according to claim 1, characterized in that, In step S12, the experimental treatment design includes, without reducing nitrogen nutrient application and with the application of controlled-release nitrogen fertilizer, taking conditioner, phosphorus nutrient and potassium nutrient as three experimental factors, taking conditioner dosage and phosphorus and potassium nutrient reduction ratio as experimental levels, using uniform experimental design to obtain the first group of experimental treatments, and designing optimized fertilization treatment as control. and, Without reducing phosphorus and potassium nutrient application, conditioner, controlled-release nitrogen fertilizer, and nitrogen nutrient were used as three experimental factors, and conditioner dosage, controlled-release nitrogen fertilizer application ratio, and nitrogen nutrient reduction ratio were used as experimental levels. The experimental parameters were "3414" and L16 (4). 3 ) or L25 (5 3 The second group of experimental treatments was obtained through orthogonal experimental design, and an optimized fertilization treatment was designed as a control. The experimental levels are set according to the experimental design within the range of conditioner dosage, the range of controlled-release nitrogen fertilizer application ratio, and the range of nitrogen, phosphorus, and potassium nutrient reduction ratio. Specifically, the conditioner dosage range is 0-250 kg / mu, the controlled-release nitrogen fertilizer application ratio range is 0%-85%, and the nitrogen, phosphorus, and potassium nutrient reduction ratios range are 0%-50%, 0%-65%, and 0%-50%, respectively.

3. The determination method according to claim 2, characterized in that, Step S14 includes conducting a field planting experiment on rice based on the first set of experimental treatments and the optimized fertilization treatment, statistically analyzing the rice yield of each experimental treatment, and then fitting the data on conditioner dosage and phosphorus and potassium nutrient reduction ratios for each experimental treatment with the rice yield data obtained for each experimental treatment using a regression model to obtain a mathematical equation relating conditioner dosage, phosphorus and potassium nutrient reduction ratios, and yield. Substituting the rice yield data of the optimized fertilization treatment into the above equation, a mathematical model of the functional relationship between conditioner dosage and phosphorus and potassium nutrient reduction ratios is obtained, i.e., the phosphorus and potassium nutrient reduction model; and... Rice field planting experiments were conducted based on the second group of experimental treatments and the optimized fertilization treatment. The rice yield of each experimental treatment was statistically analyzed. Then, the data on conditioner dosage, controlled-release urea application ratio, and nitrogen reduction ratio of each experimental treatment were fitted with the yield data obtained from each experimental treatment using a regression model to obtain mathematical equations between conditioner dosage, controlled-release urea application ratio, nitrogen reduction ratio, and rice yield. Substituting the rice yield data of the optimized fertilization treatment into the above equations, a mathematical model of the functional relationship between the nitrogen nutrient reduction ratio and conditioner dosage and controlled-release nitrogen fertilizer application ratio was obtained, namely the nitrogen nutrient reduction model.

4. The determination method according to claim 3, characterized in that, The optimized fertilization treatment involves applying fertilizer using soil testing and formula fertilization technology; Nitrogen fertilizer is applied in three applications: basal fertilizer, tillering fertilizer, and heading fertilizer. Phosphorus fertilizer and potassium fertilizer are applied as a single basal application.

5. The determination method according to claim 4, characterized in that, In step S11, determining the basic fertilizer formula for rice includes determining the type of rice, which is early rice, medium rice, or late rice.

6. A method for designing rice fertilizer formulas, characterized in that, Includes the following steps: S21: Determine the basic fertilizer formula for rice; S22: Based on the cost-effectiveness of phosphorus and potassium fertilizers and local soil and climate conditions, the reduction ratio of phosphorus and potassium fertilizers is set, and the amount of conditioner is calculated through the phosphorus and potassium nutrient reduction model. S23: Set the application ratio of controlled-release fertilizer based on the cost-effectiveness of controlled-release fertilizer and local soil and climate conditions. Calculate the nitrogen nutrient reduction ratio using the nitrogen nutrient reduction model and the amount of conditioner determined in step S22. S24: Based on the basic formula determined in step S21, the reduction ratio of phosphorus and potassium nutrients set in step S22, the determined amount of conditioner, and the controlled-release nitrogen fertilizer application ratio and the determined nitrogen nutrient reduction ratio set in step S23, the rice fertilization formula is calculated. The reduction model is obtained by the determination method described in any one of claims 1-5.

7. The method for designing rice fertilizer formulas according to claim 6, characterized in that, The controlled-release nitrogen fertilizer is resin-coated urea; The basic rice fertilization formula includes a basic application formula for early rice and a basic application formula for late or medium-season rice. The basic application formula for early rice is as follows: nitrogen application rate is 10-15 kg / mu (based on N); phosphorus application rate is 5-8 kg / mu (based on P2O5); and potassium application rate is 8-12 kg / mu (based on K2O). The basic application formula for late-season or mid-season rice is as follows: nitrogen application rate is 12-18 kg / mu (based on N); phosphorus application rate is 5-8 kg / mu (based on P2O5); and potassium application rate is 8-12 kg / mu (based on K2O). The controlled-release nitrogen fertilizer used for early rice has a controlled-release period of 50-75 days; The controlled-release nitrogen fertilizer used for late-season or mid-season rice has a controlled-release period of 70-105 days.

8. A method for revising a nitrogen, phosphorus, and potassium nutrient reduction model, wherein the nitrogen, phosphorus, and potassium nutrient reduction model is obtained by the determination method according to any one of claims 1-5, characterized in that, Includes the following steps: S31: Determine the basic fertilizer formula for rice; S32: Based on the basic formula for rice fertilization and the nutritional requirements of rice, set up optimized fertilization treatment, one-time fertilization treatment, and no fertilization treatment; S33: Conduct field planting trials and statistically analyze the yields of optimized fertilization treatment, single fertilization treatment, and no fertilization treatment during model correction. S34: Substitute the yield data of the optimized fertilization treatment, the yield of the single fertilization treatment, the yield of the no-fertilization treatment during model correction, and the yield data of the no-fertilization treatment during model determination obtained in step S33 into the correction equation to obtain the corrected model of the nitrogen, phosphorus and potassium nutrient reduction model.

9. The correction method according to claim 8, wherein the correction equation is: The corrected equation for the early rice phosphorus and potassium nutrient reduction model is: T = 0.91P + 2.01K + 4.4(Y - 458.25 + (Y1 - Y2)). In the formula, T represents the amount of conditioner, P represents the proportion of phosphorus reduction (P ≤ 65%), K represents the proportion of potassium reduction (K ≤ 50%), Y represents the yield data of the optimized fertilization treatment, Y1 represents the yield of the no-fertilization treatment when the model was determined, and Y2 represents the yield of the no-fertilization treatment when the model was corrected. Corrected equation for the phosphorus and potassium nutrient reduction model in late-season or mid-season rice: T = 0.88P + 2.05K + 3.72 (Y - 548.58 + (Y1 - Y2)); Corrected equation for nitrogen nutrient reduction model in early rice: N = (-0.11 T) 2 -0.08C 2 +74.75 T +55.85C-0.35 T C-75.41(Y-Y0)+174.49) 1 / 2 -(0.2T -0.41C+13.21), where N represents the nitrogen reduction ratio, T represents the conditioner dosage, C represents the controlled-release fertilizer application ratio, Y represents the yield data of the optimized fertilization treatment, and Y0 represents the yield of the single fertilization treatment. Corrected equation for nitrogen nutrient reduction model in late-season or mid-season rice: N = (-0.13T) 2 -0.2C 2 +47.9 T +77.28C-0.21 TC-51.04(Y-Y0)+142.56) 1 / 2 +(0.032 T +0.038C-11.94).

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