Method for determining fertilization amount of silage corn based on fertilization amount of kernel corn

Abstract

The invention discloses a method for determining the fertilization amount of silage corn based on the fertilization amount of grain corn, and belongs to the technical field of agriculture. The method comprises the following steps: obtaining nitrogen, phosphorus and potassium fertilizing amounts adopted for grain corn production of a target plot; obtaining the number of earlier days of silage corn harvesting relative to grain corn harvesting; determining whether straw returning is carried out in the corn kernel production or not; and respectively correcting the nitrogen, phosphorus and potassium fertilization amounts of the corn kernels according to the judgment result of whether the straws are returned to the field in combination with the number of days ahead, so as to obtain the recommended nitrogen, phosphorus and potassium fertilization amounts of the silage corn. According to the method, the fertilization scheme of the silage corn is rapidly generated through the correction model by utilizing the existing fertilization data of the grain corn, a large number of field trials are not needed, the fertilization precision and the fertilizer utilization efficiency are improved, and the method is suitable for corn varieties in different ripening periods.

Description

Technical Field

[0001] This invention belongs to the field of agricultural technology and relates to a method for determining the amount of fertilizer to apply to silage corn based on the amount of fertilizer applied to grain corn. Background Technology

[0002] Silage corn refers to corn harvested whole (stems, leaves, ears, and kernels) during the late milk-ripe to early waxy-ripe stage, then chopped, compacted, sealed, and fermented under anaerobic conditions to form a high-energy roughage. Silage corn has high yield, balanced nutrition, no straw waste, and high whole-plant utilization rate, making it a high-quality roughage for ruminants such as dairy cows, beef cattle, and sheep. However, there is a lack of scientific fertilization management techniques to achieve high-quality and high-yield silage corn, resulting in low fertilizer utilization efficiency and insufficient realization of the silage corn production potential.

[0003] The basic idea behind traditional soil testing and fertilizer recommendation technology is based on soil nutrient test results, crop nutrient requirements, and soil nutrient supply capacity. By analyzing the relationship between crop nutrient requirements and available soil nutrients, the application rate and ratio of each nutrient element are determined to achieve a balance between nutrient supply and crop demand. my country has a vast area dedicated to silage corn cultivation, and silage corn can be grown in any region suitable for grain corn. However, due to significant differences in climate and soil across regions, their production potential varies, and the optimal fertilization amounts also differ. Developing a suitable soil testing and fertilizer recommendation system for silage corn requires extensive field trial data, involves substantial investment, and is time-consuming and labor-intensive, making it virtually impossible to achieve in the short term. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0005] This invention solves the problems in the existing technology of relying mainly on experience or directly applying the fertilization plan of grain corn for silage corn, which leads to a mismatch between nutrient supply and actual crop needs and low fertilizer utilization efficiency. It provides a replicable and scalable technical path for constructing fertilization formulas for large-scale production of silage corn.

[0006] This addresses the technical problem that existing technologies cannot quickly and accurately calculate the specific amounts of nitrogen, phosphorus, and potassium fertilizers needed for silage corn based on existing fertilization data for grain corn.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for determining the fertilizer application rate for silage corn based on the fertilizer application rate for grain corn includes the following steps: Obtain the amount of nitrogen, phosphorus, and potassium fertilizers used in the production of grain maize in the target plot; Obtain the number of days that silage corn is harvested before grain corn; Determine whether straw return to the field was carried out during the production of the grain corn; Based on the judgment results of whether straw has been returned to the field, and combined with the number of days in advance, the nitrogen, phosphorus, and potassium fertilizer application rates of the grain corn are converted to obtain the recommended nitrogen, phosphorus, and potassium fertilizer application rates of silage corn. The conversion includes: If straw is returned to the field during grain corn production, the recommended amount of nitrogen fertilizer is increased by a first increment positively correlated with the number of days before the start of production, the recommended amount of phosphorus fertilizer is increased by a first fixed proportion based on the amount of phosphorus fertilizer used in grain corn, and the recommended amount of potassium fertilizer is increased by a second increment positively correlated with the number of days before the start of production, and the benchmark value of the second increment is higher than the first increment. If straw is not returned to the field during grain corn production, the recommended amount of nitrogen fertilizer is based on the amount of nitrogen fertilizer used for grain corn, plus a third increment positively correlated with the number of days before the start of production. The recommended amount of phosphorus fertilizer is the same as the amount of phosphorus fertilizer used for grain corn. The recommended amount of potassium fertilizer is based on the amount of potassium fertilizer used for grain corn, plus a fourth increment positively correlated with the number of days before the start of production. The base values ​​for the third and fourth increments are the same.

[0008] Preferably, in the method for determining the silage corn fertilizer application rate based on the grain corn fertilizer application rate, if straw return to the field is carried out during grain corn production, the first set of formulas is used for calculation: Ns = Ng × (1.25 + (D / 7) × 0.05); Ps = Pg × 1.05; Ks = Kg × (1.50 + (D / 7) × 0.05); If straw is not returned to the field during grain corn production, the second set of formulas is used for calculation: Ns = Ng × (1.10 + (D / 7) × 0.05); Ps = Pg × 1.0; Ks = Kg × (1.10 + (D / 7) × 0.05); Wherein, Ng, Pg, and Kg are the nitrogen, phosphorus, and potassium fertilizer application rates used for grain corn production in the target plot, respectively; Ns, Ps, and Ks are the recommended nitrogen, phosphorus, and potassium fertilizer application rates for silage corn in the target plot, respectively; and D is the number of days before the silage corn harvest compared to the grain corn harvest.

[0009] Preferably, in the method for determining the amount of fertilizer for silage corn based on the amount of fertilizer applied to grain corn, the value of the advance number of days D ranges from 7 to 21 days.

[0010] Preferably, the method for determining the fertilization amount of silage corn based on the fertilization amount of grain corn further includes a fertilization step: All the phosphate and potassium fertilizers obtained from the conversion calculation are applied as base fertilizer, and a portion of the nitrogen fertilizer is applied as base fertilizer, with the remainder applied as topdressing. The application time of the topdressing is 3 to 5 days earlier than the application time of nitrogen fertilizer for grain corn. The basal fertilizer and top dressing each account for approximately 50% of the total recommended amount of nitrogen fertilizer.

[0011] Preferably, in the method for determining the amount of fertilizer for silage corn based on the amount of fertilizer applied to grain corn, the amount of nitrogen, phosphorus, and potassium fertilizer applied to grain corn is the recommended amount of fertilizer obtained based on soil testing and formula fertilization or an intelligent nutrient expert system.

[0012] Preferably, in the method for determining the amount of fertilizer for silage corn based on the amount of fertilizer applied to grain corn, the step of determining whether straw has been returned to the field during grain corn production further includes: obtaining the actual straw return ratio R of grain corn; and when straw has been returned to the field during grain corn production, the first increment, the first fixed ratio, and the second increment are corrected according to the actual straw return ratio R, so that the first increment, the first fixed ratio, and the second increment are positively correlated with R.

[0013] Preferably, in the method for determining the silage corn fertilization rate based on the grain corn fertilization rate, the specific method for correcting according to the actual return-to-field ratio R is as follows: the recommended fertilization rates of nitrogen, phosphorus, and potassium for silage corn are calculated using the following formula: in, R The actual percentage of straw returned to the field is 0 < R ≤ 1. When R = 1, it corresponds to the full return of straw to the field.

[0014] Preferably, in the method for determining the silage corn fertilization amount based on the grain corn fertilization amount, the step of obtaining the number of days ahead of the silage corn harvest relative to the grain corn harvest further includes: calibrating the number of days ahead according to the maturity type of the corn variety planted in the target plot to obtain a calibrated number of days ahead D', and using the calibrated number of days ahead D' to replace the number of days ahead for the conversion.

[0015] Preferably, in the method for determining the silage corn fertilization amount based on the grain corn fertilization amount, the specific method for calibrating the advance number of days according to the maturity type of the corn variety planted in the target plot to obtain the calibrated advance number of days D' is as follows: When the corn variety is an early-maturing variety, the first calibration formula is used: D ′=D × α 1, where 0.8 ≤ α1 ≤ 0.9; When the corn variety is a medium-maturity variety, the second calibration formula is used: D ′= D × α 2, where 0.95≤ α 2≤1.05; When the corn variety is a late-maturing variety, the third calibration formula is used: D ′= D × α 3, where 1.1≤ α 3≤1.2.

[0016] Compared with the prior art, the present invention has the following advantages: This invention utilizes recommended fertilization schemes for grain corn to quickly generate fertilization recommendations for silage corn, reducing the need for extensive field fertilizer efficiency trials. By introducing two key parameters—whether straw is returned to the field and the number of days before harvest—this invention differentiates the fertilization amount for grain corn, precisely compensating for nutrient differences caused by early harvesting and straw removal in silage corn. It solves the problem of nutrient imbalance caused by directly applying grain corn fertilization schemes, providing a scientific and quantitative basis for silage corn fertilization.

[0017] This invention provides two sets of specific quantitative calculation formulas, transforming abstract nutritional principles into simple and operable calculation methods. This allows any region with fertilization data for grain corn and basic agricultural time information to quickly and accurately calculate the recommended nitrogen, phosphorus, and potassium fertilization amounts for silage corn, greatly reducing the technical application threshold.

[0018] This invention defines the range of advance days D as 7 to 21 days, limiting the recommended method to the most typical harvest window for silage corn production. This ensures the accuracy and effectiveness of the calculation formula in this core application scenario and avoids calculation deviations that may occur due to the D value deviating from the actual production range.

[0019] This invention proposes specific base fertilizer and topdressing allocation schemes and topdressing timing adjustment methods, which closely integrate nutrient supply with the rapid growth needs of silage corn. In particular, by advancing the nitrogen fertilizer topdressing time, it meets the peak nutrient demand of silage corn that is shifted forward due to early harvest, and further improves fertilizer utilization.

[0020] This invention ensures the accuracy and scientific validity of basic data by limiting the input of corn fertilization amount to scientific methods such as soil testing and formula fertilization or intelligent nutrient expert system. This improves the reliability of the final silage corn fertilization recommendation scheme from the source and avoids the problem of waste entering and exiting.

[0021] This invention refines the correction model by introducing the actual straw return ratio R, thus solving the problem of inaccurate nutrient compensation under conditions of incomplete straw return. By positively correlating the correction magnitude with the R value, the model can flexibly adapt to various field management practices, from small to full straw return, greatly improving the method's universality and accuracy.

[0022] This invention provides a specific correction formula that includes the actual straw return ratio R, and accurately mathematically fits the theoretical model with the complex field conditions. This enables precise quantitative correction of nitrogen, phosphorus, and potassium fertilizer application rates, and is a key step in moving this method from theory to higher-level precision practice.

[0023] This invention addresses the discrepancies in nutrient accumulation patterns caused by the genetic characteristics (length of growth period) of different varieties by calibrating the advance application rate D based on the variety's maturity date. Replacing D with the calibrated D' allows the fertilizer application conversion model to more accurately reflect the actual nutrient requirements of different silage corn varieties, significantly improving the method's applicability to various varieties.

[0024] This invention simplifies and quantifies the complex effects of varietal differences by providing specific calibration formulas and parameter ranges for early, mid, and late-maturing varieties. This allows even ordinary users lacking plant physiology knowledge to effectively calibrate core parameters based on simple variety classification, thereby obtaining more accurate fertilization recommendations.

[0025] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0026] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0027] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0028] A research team led by Professor He Ping at the Chinese Academy of Agricultural Sciences has developed a crop fertilization recommendation method based on the quantitative relationship between crop yield response and agronomic efficiency. This method analyzes the yield gain (yield response) between fertilized and unfertilized treatments, as well as the yield increment per unit of nutrient input (agronomic efficiency). Combining soil nutrient supply levels and crop nutrient requirements, it establishes a big data-driven fertilization recommendation model and applies an intelligent nutrient expert system to provide personalized fertilization plans for specific plots. This method significantly reduces the workload of field fertilizer efficiency trials, but still requires the support of experimental data.

[0029] The purpose of this invention is to overcome the problem that existing recommended fertilization methods require a large amount of field trial data. This invention provides a method for rapidly recommending silage corn fertilization based on existing local grain corn fertilization programs. This method is based on the absorption and transfer patterns of nitrogen, phosphorus, and potassium elements in the later stages of grain corn growth, the nutrient return patterns of grain corn straw returning to the field, and the characteristics of whole-plant harvesting of silage corn.

[0030] Specifically, this invention directly constructs a relationship between the amount of nitrogen, phosphorus, and potassium fertilizer applied to grain corn and the amount of fertilizer applied to silage corn based on the fertilization plan for early grain corn production, the number of days (D) that silage corn harvest is earlier than grain production harvest, and whether the recommended fertilization for grain production considers straw return to the field. It also clarifies the optimal ratio of base fertilizer and topdressing, as well as the timing of topdressing. This invention achieves a method for quickly recommending silage corn fertilization based on the fertilization plan for grain corn production without the need for separate silage corn fertilizer efficiency tests.

[0031] This invention utilizes the patterns of nitrogen, phosphorus, and potassium nutrient absorption and transfer in silage and grain corn production to develop a method for rapidly recommending silage corn fertilization based on grain corn fertilization programs. For early, mid, and late-maturing corn varieties, a key correction parameter (D) based on the number of days (days) earlier silage corn is harvested than grain corn is proposed. This determines the critical factor for considering straw return in grain production fertilization recommendations. Furthermore, combining this with the later-stage nitrogen, phosphorus, and potassium nutrient absorption and transfer patterns in grain corn, a relationship between the two is established: 1. The recommended fertilization plan for grain corn includes returning corn stalks to the field. This means that the recommended fertilization plan for grain corn reduces the nutrients provided by returning stalks to the field. Silage corn production needs to consider supplementing these nutrients to achieve balanced fertilization. Nitrogen fertilizer: Ns = Ng × (1.25 + D ÷ 7 × 0.05) Phosphate fertilizer: Ps = Pg × 1.05 Potassium fertilizer: Ks = Kg × (1.50 + D ÷ 7 × 0.05) In the formula: s represents the recommended fertilizer application rate for silage corn; g represents the recommended fertilizer application rate for grain corn; D represents the number of days that the silage corn harvest is completed ahead of the grain production harvest in this region, in days.

[0032] 2. The recommended fertilization plan for grain corn does not include straw return to the field. This means that the recommended fertilization plan for grain corn includes the nutrients provided by straw return to the field, and silage corn production does not need to consider supplementing it.

[0033] Nitrogen fertilizer: Ns = Ng × (1.10 + D ÷ 7 × 0.05) Phosphate fertilizer: Ps = Pg × 1.0 Potassium fertilizer: Ks = Kg × (1.10 + D ÷ 7 × 0.05) In the formula: s represents the recommended fertilizer application rate for silage corn; g represents the recommended fertilizer application rate for grain corn; D represents the number of days that the silage corn harvest is completed ahead of the grain corn harvest in this region, in days. Ng, Pg, and Kg represent the nitrogen, phosphorus, and potassium fertilizer application rates used for grain corn production in the target plot, respectively; Ns, Ps, and Ks represent the recommended nitrogen, phosphorus, and potassium fertilizer application rates for silage corn in the target plot, respectively.

[0034] 3. In the fertilization plan for silage corn, all phosphorus and potassium fertilizers are applied as base fertilizer. In addition, based on the characteristic that silage corn is harvested earlier than grain corn, the nitrogen fertilizer for silage corn is applied 3 to 5 days earlier than that for grain corn. At the same time, the application is combined with irrigation conditions or rainfall to improve nitrogen use efficiency.

[0035] According to one embodiment of the present invention, a method for determining the fertilizer application rate for silage corn based on the fertilizer application rate for grain corn includes the following steps: Obtain the amount of nitrogen, phosphorus, and potassium fertilizers used in the production of grain maize in the target plot; Obtain the number of days that silage corn is harvested before grain corn; Determine whether straw return to the field was carried out during the production of the grain corn; Based on the judgment results of whether straw has been returned to the field, and combined with the number of days in advance, the nitrogen, phosphorus, and potassium fertilizer application rates of the grain corn are converted to obtain the recommended nitrogen, phosphorus, and potassium fertilizer application rates of silage corn. The conversion includes: If straw is returned to the field during grain corn production, the recommended amount of nitrogen fertilizer is increased by a first increment related to the number of days before the start of production, the recommended amount of phosphorus fertilizer is increased by a first fixed proportion based on the amount of phosphorus fertilizer used in grain corn, and the recommended amount of potassium fertilizer is increased by a second increment related to the number of days before the start of production, and the benchmark value of the second increment is higher than the first increment. If straw is not returned to the field during grain corn production, the recommended amount of nitrogen fertilizer is based on the amount of nitrogen fertilizer used for grain corn, plus a third increment related to the number of days before the start of production. The recommended amount of phosphorus fertilizer is the same as the amount of phosphorus fertilizer used for grain corn. The recommended amount of potassium fertilizer is based on the amount of potassium fertilizer used for grain corn, plus a fourth increment related to the number of days before the start of production. The base values ​​for the third and fourth increments are the same.

[0036] This embodiment provides a specific application process for a method to determine the fertilization amount for silage corn based on the fertilization amount for grain corn: The method first requires obtaining the nitrogen, phosphorus, and potassium fertilizer application amounts used in the target plot when planting grain corn. It also needs to determine whether straw return was carried out during grain corn production. Additionally, it requires obtaining the number of days the silage corn harvest was carried out ahead of the grain corn harvest. Based on the determination of whether straw was returned to the field and combined with the number of days ahead, the nitrogen, phosphorus, and potassium fertilizer application amounts for grain corn are converted to obtain the recommended nitrogen, phosphorus, and potassium fertilizer application amounts for silage corn. Specifically, if straw return was carried out during grain corn production, the recommended nitrogen fertilizer application amount is increased by a first incremental phosphorus fertilizer application amount related to the number of days ahead, the recommended phosphorus fertilizer application amount is increased by a first fixed-ratio potassium fertilizer application amount, and the recommended potassium fertilizer application amount is increased by a second incremental amount related to the number of days ahead, with the base value of the second incremental amount being higher than the first incremental amount. If straw is not returned to the field during grain corn production, the recommended nitrogen fertilizer amount is based on the nitrogen fertilizer amount for grain corn plus a third increment related to the number of days before the start of production. The recommended phosphorus fertilizer amount is the same as the phosphorus fertilizer amount for grain corn. The recommended potassium fertilizer amount is based on the potassium fertilizer amount for grain corn plus a fourth increment related to the number of days before the start of production, and the baseline values ​​for the third and fourth increments are the same.

[0037] In a specific embodiment, a test field was selected. The previous crop of this field was grain corn, with nitrogen fertilizer applied at a rate of 15 kg / mu, pure nitrogen-phosphorus fertilizer at a rate of 6 kg / mu (P2O5), and potassium fertilizer at a rate of 8 kg / mu (K2O). Straw was crushed and returned to the field during this grain corn production. The plan was to plant silage corn on the same field, with the silage corn harvest time 14 days earlier than the normal grain corn harvest time. Based on the determination of whether straw was returned to the field (i.e., straw return was implemented) and the 14-day advance harvest time, the above conversion rules were used for calculation. The first increment related to the advance harvest time is reflected in an increase in the recommended nitrogen fertilizer amount, with its baseline value set higher than the original nitrogen fertilizer application for grain corn. The recommended phosphorus fertilizer amount is increased by a first fixed proportion based on the phosphorus fertilizer application for grain corn. The recommended potassium fertilizer amount is increased by a second increment related to the advance harvest time based on the potassium fertilizer application for grain corn, and because straw return removes a large amount of potassium, the baseline value for the second increment is set higher to compensate for the potassium loss. The final calculated recommended nitrogen fertilizer application rate for silage corn is approximately 21.0 kg per mu (667 square meters), the recommended pure nitrogen and phosphorus fertilizer application rate is approximately 6.3 kg P2O5 per mu, and the recommended potassium fertilizer application rate is approximately 13.6 kg K2O per mu. This recommended fertilization rate takes into account the shortened growth cycle caused by early harvesting of silage corn and the actual nutrient return under the practice of returning straw to the field, aiming to balance soil nutrient supply with the overall growth needs of the silage corn plant.

[0038] In another embodiment, a different experimental field was selected. The previous crop of this field was grain corn, with nitrogen fertilizer applied at 14 kg pure nitrogen per mu (approximately 0.067 hectares), phosphorus fertilizer at 5 kg P2O5 per mu (approximately 0.067 hectares), and potassium fertilizer at 7 kg K2O per mu (approximately 0.067 hectares). No straw was returned to the field during this grain corn production; the straw was removed from the field. The plan was to plant silage corn on the same field, with the silage corn harvest time 10 days earlier than the normal grain corn harvest time. Based on the determination of whether straw was returned to the field (i.e., no straw was returned) and the 10-day advance harvest time, the above conversion rules were used for calculation. Since no straw nutrient return occurred without straw return, the recommended amounts of nitrogen and potassium fertilizers were increased by the same base value as the grain corn application rate, based on the advance harvest time. The recommended phosphorus fertilizer application rate was the same as the grain corn application rate. The final calculation yielded a recommended nitrogen fertilizer application rate of approximately 17.0 kg pure nitrogen per mu (667 square meters), a phosphorus fertilizer application rate of 5.0 kg P2O5 per mu, and a potassium fertilizer application rate of approximately 8.5 kg K2O per mu. This recommended fertilization rate primarily compensates for the increased nutrient demand of the plants due to early harvesting, without considering the nutrient return from straw return to the field.

[0039] Existing technologies simply replicate fertilization schemes designed for grain corn to silage corn production, completely ignoring the differences in nutrient requirements resulting from the different utilization methods of the two types of corn. The ultimate goal of grain corn production is to harvest the grains, and its nutrient absorption focus shifts to the grains in the later stages. Silage corn, on the other hand, harvests all above-ground parts, including stems, leaves, and ears. The total and proportional requirements for nitrogen, phosphorus, and potassium, especially potassium, differ significantly between the two. Furthermore, whether or not straw is returned to the field directly affects soil nutrient cycling and reuse. In grain corn production, if straw is returned, the fertilization scheme already considers the nutrients released by straw decomposition. However, silage corn harvesting removes all nutrients, thus requiring additional supplementation. This invention introduces two key correction factors—straw return status and the number of days before harvest—to systematically transform the fertilization amount for grain corn, shifting silage corn fertilization decisions from blind application to scientific calculation.

[0040] This invention simplifies the complex problem of nutrient management into the judgment and adjustment of a few key parameters, making the formulation of silage corn fertilization programs more data-driven. It clarifies the basic principles of conversion, dividing the adjustment path into two different approaches based on whether straw is returned to the field: when straw is returned, because a large amount of nutrients are removed, the adjustment range for nitrogen, phosphorus, and potassium is greater than or different from that when straw is not returned, reflecting respect for the soil nutrient cycle. It introduces a dynamic parameter of harvest advance days, so that the adjustment of fertilizer application is no longer a fixed value, but can be linked to the actual harvest time; the more days ahead the harvest, the shorter the plant's growth time in the field, the greater the interruption of its nutrient absorption and accumulation process, and the greater the need for supplemental nutrients. This dynamic adjustment mechanism significantly improves the accuracy of fertilization recommendations. This invention employs different adjustment methods for nitrogen, phosphorus, and potassium nutrients. For example, when straw is returned to the field, phosphorus fertilizer is increased at a fixed ratio, while nitrogen and potassium are increased in increments related to the number of days, with the potassium increment having a higher baseline value than nitrogen. This reflects the migration and transformation patterns of different nutrients within the plant, as well as the differences in the effects of straw return and early harvest: nitrogen is easily mobile and has multiple loss pathways; potassium has a high content in straw and is largely carried away. This invention provides a versatile and easy-to-operate technical approach for the scientific fertilization of silage corn. It eliminates the need for complex field trials, allowing for the rapid generation of targeted fertilization plans using only existing grain corn production data. This significantly reduces the cost of technology promotion and application, and is conducive to promoting the standardization and precision of silage corn production.

[0041] According to one embodiment of the present invention, the method for determining the silage corn fertilizer application rate based on the grain corn fertilizer application rate, if straw return to the field is carried out in grain corn production, uses the first set of formulas for calculation: Ns = Ng × (1.25 + (D / 7) × 0.05); Ps = Pg × 1.05; Ks = Kg × (1.50 + (D / 7) × 0.05); If straw is not returned to the field during grain corn production, the second set of formulas is used for calculation: Ns = Ng × (1.10 + (D / 7) × 0.05); Ps = Pg × 1.0; Ks = Kg × (1.10 + (D / 7) × 0.05); Wherein, Ng, Pg, and Kg are the nitrogen, phosphorus, and potassium fertilizer application rates used for grain corn production in the target plot, respectively; Ns, Ps, and Ks are the recommended nitrogen, phosphorus, and potassium fertilizer application rates for silage corn in the target plot, respectively; and D is the number of days before the silage corn harvest compared to the grain corn harvest.

[0042] Specifically, an experimental field was selected. The previous crop of this field was grain corn, which was fertilized with 15 kg of pure nitrogen, 6 kg of P2O5, and 8 kg of K2O per mu (approximately 0.067 hectares) of nitrogen fertilizer, and straw was crushed and returned to the field. The plan is to plant silage corn on the same field, with a harvest time 14 days earlier than the normal harvest time for grain corn. The recommended fertilizer application rate for silage corn was calculated using the formula for straw return. Substituting Ng=15, Pg=6, Kg=8, and D=14 into the formula, the recommended nitrogen fertilizer amount is Ns=15×1.25+14÷7×0.05=15×1.25+0.1=15×1.35=20.25, which is approximately 20.3 kg of pure nitrogen per mu; the recommended phosphorus fertilizer amount is Ps=6×1.05=6.3, which is 6.3 kg of P2O5 per mu; and the recommended potassium fertilizer amount is Ks=8×1.50+14÷7×0.05=8×1.50+0.1=8×1.6=12.8, which is 12.8 kg of K2O per mu. This fertilizer application rate is calculated based on the formula, taking into account the changes in nutrient requirements caused by the early harvest of silage corn and the nutrient compensation requirements brought about by straw returning to the field.

[0043] By providing specific quantitative calculation formulas, theoretical conversion rules are transformed into directly operable mathematical expressions, enabling the rapid and accurate determination of fertilization amounts for silage corn under different regional and agricultural time conditions. The coefficients 1.25, 1.05, 1.50, and 0.05 in these formulas are derived from extensive studies of corn nutrient absorption patterns and the effect of straw return to the field, ensuring the scientific rigor and accuracy of the conversion. By simplifying complex agricultural science principles into simple arithmetic operations, the fertilization amount for silage corn can be calculated immediately by knowing only the fertilization amount for grain corn and the number of days required in advance. This greatly facilitates grassroots agricultural technology extension and farmer application, avoiding fertilization deviations caused by insufficient experience or rough estimations, thereby effectively improving fertilizer utilization efficiency and silage corn yield.

[0044] According to one embodiment of the present invention, the method for determining the amount of fertilizer for silage corn based on the amount of fertilizer applied to grain corn has the value of the advance number D ranging from 7 to 21 days.

[0045] A test field was selected. The previous crop of this field was grain corn, with nitrogen fertilizer applied at a rate of 14 kg pure nitrogen per mu (0.067 hectares), phosphorus fertilizer at a rate of 5 kg P2O5 per mu (0.067 hectares), and potassium fertilizer at a rate of 7 kg K2O per mu (0.067 hectares). No straw was returned to the field during production. The plan was to plant silage corn, with different numbers of days prior to the normal harvest time of grain corn to examine the impact of these ranges. First, an example was set up with a 14-day advance harvest. Using the formula for no straw return, the recommended nitrogen fertilizer rate was calculated as follows: Ns = 14 × 1.10 + 14 ÷ 7 × 0.05 = 14 × 1.10 + 0.1 = 14 × 1.2 = 16.8 kg pure nitrogen per mu; the recommended potassium fertilizer rate was calculated as follows: Ks = 7 × 1.10 + 14 ÷ 7 × 0.05 = 7 × 1.10 + 0.1 = 7 × 1.2 = 8.4 kg K2O per mu; and the recommended phosphorus fertilizer rate remained at 5 kg P2O5 per mu. In actual production, when fertilizer is applied according to this recommended amount, the silage corn grows well and there is no nutrient deficiency in the later stages.

[0046] This embodiment clarifies that the reasonable range for the advance harvesting period is 7 to 21 days, which precisely covers the typical advance period between silage corn harvesting and grain corn harvesting in major corn-producing areas of my country. Within this range, the linear increment term in the formula is directly proportional to the number of days, accurately reflecting the pattern of nutrient demand changes with harvest time. Exceeding this range may introduce significant errors. This embodiment provides a clear range of applicable parameters for production practice, avoiding users' misuse of the formula in extreme situations and ensuring the reliability of the recommended results. At the same time, this range also conforms to the actual agricultural time for silage corn production, making the method more practical and instructive.

[0047] According to one embodiment of the present invention, the method for determining the fertilization amount of silage corn based on the fertilization amount of grain corn further includes a fertilization step: All the phosphate and potassium fertilizers obtained from the conversion calculation are applied as base fertilizer, and a portion of the nitrogen fertilizer is applied as base fertilizer, with the remainder applied as topdressing. The application time of the topdressing is 3 to 5 days earlier than the application time of nitrogen fertilizer for grain corn. The basal fertilizer and top dressing each account for approximately 50% of the total recommended amount of nitrogen fertilizer.

[0048] A test field was selected, and the recommended fertilization rates for silage corn were calculated: 18 kg of pure nitrogen per mu (approximately 0.067 hectares), 6 kg of P2O5 per mu (approximately 0.067 hectares) of phosphorus fertilizer, and 12 kg of K2O per mu (approximately 0.067 hectares) of potassium fertilizer. Fertilization was carried out as follows: all phosphorus and potassium fertilizers were applied as base fertilizer in one application; nitrogen fertilizer was divided into two parts: 50% (9 kg of pure nitrogen per mu) was applied as base fertilizer along with the phosphorus and potassium fertilizers, and the other 50% was applied as topdressing. The timing of topdressing needed to be determined based on the nitrogen fertilizer application time for grain corn. In this region, grain corn is usually topdressed with nitrogen fertilizer around July 20th during the large trumpet stage. Silage corn should be topdressed 3 to 5 days earlier, therefore, July 16th was chosen as the date for topdressing. This arrangement was to ensure that the peak nutrient supply period of topdressing coincided with the peak nutrient demand period of rapid growth in silage corn.

[0049] This embodiment applies all phosphorus and potassium fertilizers as base fertilizer to meet the crop's early-stage phosphorus and potassium needs. Meanwhile, nitrogen fertilizer is applied in multiple applications with adjusted topdressing timing, fully considering the advanced growth period caused by the early harvest of silage corn. The 50 / 50 ratio of base and topdressing nitrogen ensures sufficient nitrogen to initiate growth in the early stages, while the later topdressing replenishes the nitrogen consumed during vigorous growth, avoiding nitrogen waste and loss. The seemingly minor adjustment of applying topdressing 3 to 5 days earlier than for grain corn precisely matches the earlier nutrient absorption peak of silage corn due to its early harvest, achieving optimal synchronization between nutrient supply and crop demand. This further optimizes the spatial and temporal matching of nutrients at the fertilization operation level, not only improving fertilizer utilization but also reducing the environmental pollution risk caused by improper fertilization, providing a set of supporting fertilization technical specifications for high-yield and high-quality silage corn cultivation.

[0050] According to one embodiment of the present invention, the method for determining the fertilization amount of silage corn based on the fertilization amount of grain corn, wherein the nitrogen, phosphorus, and potassium fertilization amounts of the grain corn are recommended fertilization amounts obtained based on soil testing and formula fertilization or an intelligent nutrient expert system.

[0051] Two plots were selected for a comparative experiment, with similar soil types and fertility levels. The first plot, serving as an example, used recommended nitrogen, phosphorus, and potassium (NPK) fertilizer application rates for grain corn production based on soil testing and formula fertilization methods. Specifically, this was 14 kg of pure nitrogen, 5.5 kg of P2O5, and 7.5 kg of K2O per acre. This recommendation fully considered soil nutrient test results and crop nutrient requirements. The second plot, serving as a control, used empirical fertilizer application rates long used by local farmers, without scientific testing. These rates were 16 kg of pure nitrogen, 6 kg of P2O5, and 6 kg of K2O per acre, which showed an overemphasis on nitrogen and a underemphasis on potassium. Both plots incorporated straw return to the field during grain corn planting. A plan was made to plant silage corn on the same plot, with silage corn harvested 14 days earlier than grain corn harvest. A conversion calculation was performed to obtain the recommended fertilizer application rates for silage corn. In this example, the silage corn fertilizer application rate, converted from the scientifically recommended grain corn fertilizer application rate, is approximately 18.9 kg of pure nitrogen, 5.8 kg of P2O5, and 12.0 kg of K2O. The grain corn fertilizer application rate is based on recommendations obtained through scientific methods such as soil testing and fertilizer recommendation or intelligent nutrient expert systems. This example ensures the accuracy and scientific validity of the input data from the outset. Soil testing and fertilizer recommendation can determine the optimal fertilizer application rate based on the actual nutrient supply capacity of the soil and the crop's nutrient requirements. Intelligent nutrient expert systems further combine big data and model optimization; both avoid the blindness of experience-based fertilization. The grain corn fertilizer application rate must be based on recommendations obtained through scientific methods such as soil testing and fertilizer recommendation or intelligent nutrient expert systems. This limitation ensures the accuracy and scientific validity of the input data from the outset. Soil testing and fertilizer recommendation can determine the optimal fertilizer application rate based on the actual nutrient supply capacity of the soil and the crop's nutrient requirements. Intelligent nutrient expert systems further combine big data and model optimization; both avoid the blindness of experience-based fertilization. This embodiment ensures that the entire conversion method is scientifically sound and reliable, avoiding deviations in conversion results due to inaccurate basic data, thus truly achieving precision fertilization. At the same time, it guides agricultural producers to adopt scientific fertilization decision-making methods, promoting the overall advancement of fertilization technology.

[0052] According to one embodiment of the present invention, the method for determining the amount of fertilizer for silage corn based on the amount of fertilizer applied to grain corn, the step of determining whether straw return to the field has been carried out in grain corn production further includes: obtaining the actual straw return ratio R of grain corn; and when straw return to the field has been carried out in grain corn production, the first increment, the first fixed ratio and the second increment are corrected according to the actual straw return ratio R, so that the first increment, the first fixed ratio and the second increment are positively correlated with R.

[0053] A test field was selected. The previous crop of this field was grain corn, and the fertilizer application rates were 15 kg pure nitrogen, 6 kg P2O5, and 8 kg K2O per mu (approximately 0.067 hectares). Although straw was returned to the field, the actual return rate was not 100%; only about 60% of the straw was crushed and returned, while the remaining 40% was removed from the field. According to the method of this invention, if we simply assume straw return without considering the actual return rate, we can directly calculate the fertilization amount for silage corn using the formula for straw return, resulting in approximately 20.3 kg pure nitrogen, 6.3 kg P2O5, and 12.8 kg K2O. However, the actual return rate is only 60%, meaning that only 60% of the nutrients from the straw were returned. Therefore, the increment needs to be corrected based on R. In this experiment, the first incremental, first fixed, and second incremental amounts were corrected based on the actual straw return ratio R=0.6, ensuring the correction magnitude was positively correlated with R. This means the lower the actual straw return ratio, the more additional nutrients are needed. The corrected fertilizer application rate should be higher than the rate used when simply determining straw return, to compensate for the portion of straw removed. In actual application, two treatments were set up: Treatment 1 used the uncorrected fertilizer application rate, and Treatment 2 used the corrected rate based on R. During the growth period, plants in Treatment 1 showed slight signs of nutrient deficiency in the mid-to-late stages, especially potassium, and premature senescence of the lower leaves; while plants in Treatment 2 grew vigorously, had a longer leaf functional period, and did not experience nutrient deficiency in the later stages. At harvest, the biomass yield of Treatment 2 was significantly higher than that of Treatment 1. In actual production, straw return to the field is often difficult to achieve at full volume due to mechanical, climatic, or agronomical requirements. Ignoring this factor can lead to insufficient or excessive nutrient compensation. This embodiment significantly improves the accuracy and adaptability of the fertilization recommendation model, enabling dynamic adjustment of the fertilization amount based on different return-to-field ratios. This avoids nutrient supply deviations caused by changes in the return-to-field ratio, thereby better balancing soil nutrients and improving fertilizer utilization efficiency.

[0054] According to one embodiment of the present invention, the method for determining the amount of fertilizer for silage corn based on the amount of fertilizer applied to grain corn is described below. The specific method for adjusting the actual return-to-field ratio R is as follows: Calculate the recommended nitrogen, phosphorus, and potassium fertilizer application rates for silage corn using the following formula: Where R is the actual proportion of straw returned to the field, and its value ranges from 0 to 1. When R=1, it corresponds to the full return of straw to the field.

[0055] A test field was selected. The previous crop of this field was grain corn, which was fertilized with 15 kg of pure nitrogen per mu (667 square meters), 6 kg of P2O5 per mu (667 square meters), and 8 kg of K2O per mu (800 square meters). Straw was returned to the field during production, with an actual return rate R of 0.7, meaning 70% of the straw was crushed and returned. The silage corn harvest was 14 days earlier than the grain corn harvest. The recommended nitrogen fertilizer amount (Ns) was calculated using the following modified formulas: Ns = Ng × 1.25 + D / 7 × 0.05 × 1 + R; Ps = Pg × 1.05 + 0.05 × R; Ks = Kg × 1.50 + D / 7 × 0.05 × 1 + R. Substituting the values: Ng=15, Pg=6, Kg=8, D=14, R=0.7, we calculate the nitrogen fertilizer Ns = 15 × 1.25 + 14÷7×0.05×1.7 = 15 × 1.25 +0.1×1.7 = 18.75 + 0.17 = 18.92, which is approximately 18.9 kg of pure nitrogen per mu; the phosphorus fertilizer Ps = 6 × 1.05+ 0.05×0.7 = 6.3 + 0.035 = 6.335, which is approximately 6.3 kg of P2O5 per mu; the potassium fertilizer Ks = 8 × 1.50 + 0.1×1.7 = 12 + 0.17 = 12.17, which is approximately 12.2 kg of K2O per mu. The formula used only considers straw return without taking into account R (nutrient availability), resulting in 20.3 kg of nitrogen, 6.3 kg of phosphorus, and 12.8 kg of potassium fertilizer according to the original formula. The fertilizer application amounts differ between the two treatments. The modified treatment, considering only 70% straw return, provides slightly less nutrient compensation than the case of full straw return, but more than the case of no straw return. Actual field observations showed that the treatment using the modified formula resulted in robust corn growth and a balanced nutrient supply and demand; while the treatment using the original formula, due to the additional compensation of some unnecessary nutrients, led to a slight potassium surplus in the later stages, although no significant adverse effects were observed, but there was some waste from a fertilizer utilization perspective. This embodiment greatly improves the universality and accuracy of the method, providing strong support for refined nutrient management.

[0056] According to one embodiment of the present invention, the method for determining the silage corn fertilization amount based on the grain corn fertilization amount, the step of obtaining the number of days ahead of the silage corn harvest relative to the grain corn harvest further includes: calibrating the number of days ahead according to the maturity type of the corn variety planted in the target plot to obtain a calibrated number of days ahead D', and using the calibrated number of days ahead D' to replace the number of days ahead for the conversion.

[0057] Three experimental fields were selected, each planted with a maize variety with different maturity periods: early-maturing, mid-maturing, and late-maturing. The soil fertility conditions and fertilization practices of the previous grain maize crop were largely consistent across all three fields. The previous grain maize crop received 15 kg of pure nitrogen, 6 kg of P2O5, and 8 kg of K2O per mu (approximately 0.067 hectares) of nitrogen fertilizer, and straw was returned to the field during production. The plan is to plant silage maize in the same area, with the nominal harvest date for silage maize being 14 days earlier than that for grain maize, according to local agricultural calendars. The advance date D needs to be calibrated according to the variety maturity type to obtain a calibrated advance date D', which will then replace the original D in the fertilizer application conversion calculation.

[0058] For early-maturing varieties, using the first calibration formula with a calibration coefficient α1 of 0.85, the calibrated advance date D' = 14 × 0.85 = 11.9 days, rounded to 12 days. For medium-maturing varieties, using the second calibration formula with a calibration coefficient α2 of 1.0, D' = 14 × 1.0 = 14 days. For late-maturing varieties, using the third calibration formula with a calibration coefficient α3 of 1.15, D' = 14 × 1.15 = 16.1 days, rounded to 16 days. Substitute these values ​​into the formula for straw return to the field to calculate the recommended fertilizer application rate for silage corn.

[0059] Observations during actual growth showed that, in plots using the calibrated D' value, early-maturing varieties exhibited good matching between growth rhythm and nutrient supply, with no instances of delayed maturity due to excessive fertilization; mid-maturing varieties grew normally; and late-maturing varieties, due to the increased D' value after calibration, required a corresponding increase in fertilization, meeting their nutrient needs during their longer growth period, with no nutrient deficiency observed later. This embodiment enables the fertilization conversion model to adapt to the biological characteristics of varieties with different maturity periods. Early-maturing varieties have shorter growth periods, so the impact of early harvesting is relatively smaller, requiring a reduced increment; late-maturing varieties have longer growth periods, so the impact of early harvesting is greater, requiring a larger increment. This embodiment significantly improves the applicability of the fertilization recommendation method to different varieties, avoiding fertilization deviations caused by ignoring variety differences. It allows the same basic fertilization amount, after maturity calibration, to meet the precise nutrient requirements of different varieties of silage corn, further broadening the application scope of the method and improving the accuracy of recommendations.

[0060] According to one embodiment of the present invention, the method for determining the silage corn fertilization amount based on the grain corn fertilization amount, wherein the advance number of days is calibrated according to the maturity type of the corn variety planted in the target plot to obtain the calibrated advance number of days D', is specifically described as follows: When the corn variety is an early-maturing variety, the first calibration formula is used: D ′= D × α 1, where 0.8 ≤ α1 ≤ 0.9; When the corn variety is a medium-maturity variety, the second calibration formula is used: D ′= D × α 2, where 0.95≤ α 2≤1.05; When the corn variety is a late-maturing variety, the third calibration formula is used: D ′= D × α 3, where 1.1≤ α 3≤1.2 Specific calibration formulas and coefficient ranges are provided for early, mid, and late-maturing varieties, precisely mathematically representing the impact of varietal differences on the number of days ahead of maturity. The calibration coefficient for early-maturing varieties is less than 1, for late-maturing varieties it is greater than 1, and for mid-maturing varieties it is close to 1, a pattern consistent with the biological characteristics of varieties with different maturity periods. A concrete and operable quantitative calibration tool is provided, enabling even users lacking varietal expertise to accurately correct for the number of days ahead of maturity based on simple maturity classifications and given coefficient ranges, thereby obtaining fertilization recommendations that match varietal characteristics. This calibration mechanism extends the applicability of the method from single varieties to all maturity types, achieving truly differentiated and precise fertilization based on varietal characteristics.

[0061] This experiment was conducted from June to October 2025 at Linjiang Farm, Huanghua City, Hebei Province. The soil was slightly saline-alkali soil with a salt content of 2‰, loam texture, and pH of 8.3. The soil organic matter content was 1.1%, available nitrogen was 95 mg / kg, available phosphorus was 7 mg / kg, and available potassium was 150 mg / kg.

[0062] The experiment included two treatments: a conventional treatment and the treatment based on this invention. Each treatment covered an area of ​​0.2 hectares. The maize variety used was Chunfeng 706, and all maize was sown on June 25th at a planting density of 63,000 plants / hm². Locally, silage maize is harvested 14 days earlier than grain maize.

[0063] Conventional treatment involves applying fertilizer according to the local fertilization rate for grain maize production, with nitrogen fertilizer application rate: urea 289 kg / hm². 2 The equivalent of pure nitrogen (N) is 133 kg / hm². 2 Phosphate fertilizer: Superphosphate 958 kg / hm 2 Equivalent to 115 kg / hm² of available nutrients (P₂O₅). 2 Potassium fertilizer: 72 kg / hm² of potassium sulfate 2 Equivalent to 37 kg / hm² of available nutrients (K₂O) 2 50% of the nitrogen fertilizer, all of the phosphorus and potassium fertilizers, should be applied as base fertilizer in one go. The remaining 50% of the nitrogen fertilizer should be applied as top dressing during the jointing stage (July 20th).

[0064] This invention involves returning corn stalks to the field and fertilizing according to a harvest plan 14 days earlier. Nitrogen fertilizer application rate: 391 kg / hm² of urea. 2 The equivalent of pure nitrogen (N) is 180 kg / hm². 2 Phosphate fertilizer: 1000 kg / hm² of superphosphate 2 Equivalent to 120 (P2O5) kg / hm² of available nutrients 2 Potassium fertilizer: 115 kg / hm² of potassium sulfate 2 Equivalent to 60 kg / hm² of available nutrients (K₂O) 2 50% of the nitrogen fertilizer, all phosphorus and potassium fertilizers were applied as base fertilizer in one go. The remaining 50% of the nitrogen fertilizer was applied as top dressing at the jointing stage (July 16). The land preparation, planting, and pest and weed management measures were the same for both treatments, and the corn was harvested uniformly on October 2 when it entered the waxy maturity stage.

[0065] The silage yield treated by this invention is 50% higher than that treated by conventional methods, and the partial productivity of nitrogen, phosphorus, and potassium is also improved.

[0066] Table 1 Comparison of fertilizer utilization efficiency of maize under different treatments index Silage yield (tons / hectare) Nitrogen derivative productivity (kg / kg) Phosphorus productivity (kg / kg) Potassium partial productivity (kg / kg) Standard processing 30 78.94 91.3 243.5 Invention processing 45 87.5 131.3 262.5 Increase (%) 50 10.8 43.8 0.78 Note: Nitrogen partial productivity = silage dry matter yield ÷ nitrogen fertilizer application rate (N); Phosphorus partial productivity = Silage dry matter yield ÷ Phosphate fertilizer application rate (P2O5) Potassium partial productivity = silage dry matter yield ÷ potassium fertilizer application rate (K2O).

[0067] The above results demonstrate that, while maintaining the local conventional fertilization intensity for grain corn as a benchmark, correcting the fertilization structure based on the conversion model of this invention can improve fertilizer utilization efficiency while increasing silage corn yield, thereby achieving the technical objective of rapidly recommending silage corn fertilization amounts based on grain corn fertilization schemes.

[0068] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A method for determining the fertilizer application rate for silage corn based on the fertilizer application rate for grain corn, characterized in that, Includes the following steps: Obtain the amount of nitrogen, phosphorus, and potassium fertilizers used in the production of grain maize in the target plot; Obtain the number of days that silage corn is harvested before grain corn; Determine whether straw return to the field was carried out during the production of the grain corn; Based on the judgment results of whether straw has been returned to the field, and combined with the number of days in advance, the nitrogen, phosphorus, and potassium fertilizer application rates of the grain corn are converted to obtain the recommended nitrogen, phosphorus, and potassium fertilizer application rates of silage corn. The conversion includes: If straw is returned to the field during grain corn production, the recommended amount of nitrogen fertilizer is increased by a first increment related to the number of days before the start of production, the recommended amount of phosphorus fertilizer is increased by a first fixed proportion based on the amount of phosphorus fertilizer used in grain corn, and the recommended amount of potassium fertilizer is increased by a second increment related to the number of days before the start of production, and the benchmark value of the second increment is higher than the first increment. If straw is not returned to the field during grain corn production, the recommended amount of nitrogen fertilizer is based on the amount of nitrogen fertilizer used for grain corn, plus a third increment related to the number of days before the start of production. The recommended amount of phosphorus fertilizer is the same as the amount of phosphorus fertilizer used for grain corn. The recommended amount of potassium fertilizer is based on the amount of potassium fertilizer used for grain corn, plus a fourth increment related to the number of days before the start of production. The base values ​​for the third and fourth increments are the same.

2. The method for determining the silage corn fertilization rate based on the grain corn fertilization rate as described in claim 1, characterized in that, If straw is returned to the field during grain corn production, then the first set of formulas should be used for calculation: Ns = Ng × (1.25 + (D / 7) × 0.05); Ps = Pg × 1.05; Ks = Kg × (1.50 + (D / 7) × 0.05); If straw is not returned to the field during grain corn production, the second set of formulas is used for calculation: Ns = Ng × (1.10 + (D / 7) × 0.05); Ps = Pg × 1.0; Ks = Kg × (1.10 + (D / 7) × 0.05); Wherein, Ng, Pg, and Kg are the nitrogen, phosphorus, and potassium fertilizer application rates used for grain corn production in the target plot, respectively; Ns, Ps, and Ks are the recommended nitrogen, phosphorus, and potassium fertilizer application rates for silage corn in the target plot, respectively; and D is the number of days before the silage corn harvest compared to the grain corn harvest.

3. The method for determining the silage corn fertilization rate based on the grain corn fertilization rate as described in claim 1, characterized in that, The value of the advance notice period D ranges from 7 to 21 days.

4. The method for determining the silage corn fertilization amount based on the grain corn fertilization amount as described in claim 1, characterized in that, It also includes the fertilization step: All the phosphate and potassium fertilizers obtained from the conversion calculation are applied as base fertilizer, a portion of the nitrogen fertilizer is applied as base fertilizer, and the remainder is applied as topdressing. The application time of the topdressing is 3 to 5 days earlier than the application time of nitrogen fertilizer for grain corn. The basal fertilizer and top dressing each account for 50% of the total recommended amount of nitrogen fertilizer.

5. The method for determining the silage corn fertilization rate based on the grain corn fertilization rate as described in claim 1, characterized in that, The nitrogen, phosphorus, and potassium fertilizer application rates for the corn kernels are recommended based on soil testing and fertilizer formulation or intelligent nutrient expert systems.

6. The method for determining the silage corn fertilization rate based on the grain corn fertilization rate as described in claim 1, characterized in that, The steps for determining whether straw return to the field has been carried out in grain corn production also include: obtaining the actual straw return ratio R of grain corn; and when straw return to the field has been carried out in grain corn production, correcting the first increment, the first fixed ratio and the second increment according to the actual return ratio R, so that the first increment, the first fixed ratio and the second increment are positively correlated with R.

7. The method for determining the silage corn fertilization rate based on the grain corn fertilization rate as described in claim 6, characterized in that, The specific method for adjusting the actual return-to-field ratio R is as follows: Calculate the recommended nitrogen, phosphorus, and potassium fertilizer application rates for silage corn using the following formula: Where R is the actual proportion of rice returned to the field, and its value ranges from 0 to 1.

8. The method for determining the silage corn fertilization rate based on the grain corn fertilization rate as described in claim 1, characterized in that, The step of obtaining the number of days ahead of the harvest of silage corn relative to the harvest of grain corn further includes: calibrating the number of days ahead based on the maturity type of the corn variety planted in the target plot to obtain a calibrated number of days ahead D', and using the calibrated number of days ahead D' to replace the number of days ahead for the conversion.

9. The method for determining the fertilization amount of silage corn based on the fertilization amount of grain corn as described in claim 1, characterized in that, The specific method for calibrating the advance date based on the maturity type of the corn variety planted in the target plot to obtain the calibrated advance date D' is as follows: When the corn variety is an early-maturing variety, the first calibration formula is used: D ′= D × α 1, where 0.8 ≤ α1 ≤ 0.9; When the corn variety is a medium-maturity variety, the second calibration formula is used: D ′= D × α 2, where 0.95≤ α 2≤1.05; When the corn variety is a late-maturing variety, the third calibration formula is used: D ′= D × α 3, where 1.1≤ α 3≤1.2.

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