A corn-specific blended fertilizer and its preparation method

Abstract

This invention relates to the field of fertilizers, specifically to a corn-specific blended fertilizer and its preparation method. The corn-specific blended fertilizer, calculated by weight, comprises: 20-40 parts of a loaded coated fertilizer and 60-80 parts of an inorganic compound fertilizer. The corn-specific blended fertilizer provided by this invention uses urea granules as the nutrient core, coated with a plant oil polyol-based polyurethane coating material. This can improve and reduce the release rate of nitrogen nutrients, ensuring nitrogen nutrient supply throughout the corn's growth cycle. By adding modified polyaspartic acid, inhibitors, and synergists to the coating material, the effects of pH, nutrient ions, and other factors on the effectiveness of fertilizer inhibitors during fertilizer production can be avoided, further improving nitrogen fertilizer utilization and reducing greenhouse gas emissions.

Description

Technical Field

[0001] This invention relates to the field of fertilizers, specifically to a corn-specific blended fertilizer and its preparation method. Background Technology

[0002] Currently, the main measures to reduce nitrogen fertilizer emissions in farmland include the application of stabilized fertilizers and the promotion and application of emission reduction technologies. In actual production, the application of emission reduction technologies often requires growers to possess certain professional knowledge and skills, which presents difficulties in the promotion process. Therefore, stabilized fertilizers, which are convenient to apply, are more favored by growers. The core of stabilized fertilizers lies in fertilizer inhibitors. During the production process, fertilizer inhibitors are easily affected by factors such as temperature, pH, and nutrient molecule concentrations, reducing the effectiveness of the inhibitors in the finished product and affecting the final application effect.

[0003] In agricultural production, high-intensity planting activities can lead to soil degradation and limited crop yield increases. Targeted application of micronutrient fertilizers can not only improve the inorganic nutrient balance of crops and increase crop yields, but also improve the quality of agricultural products. Currently, many fertilizer products on the market add micronutrients through internal additives. However, during the production process, micronutrient ions, such as zinc, can react with phosphate ions to form precipitates, affecting the availability of the elements.

[0004] Corn is one of my country's three major staple crops, playing a vital role in ensuring national food security. Fertilization is one of the most important agricultural production measures in corn cultivation; to achieve high yields, it is essential to ensure nutrient supply throughout the growth cycle, especially during the fruiting period. Currently, corn fertilization in my country generally suffers from problems such as excessive nitrogen fertilizer application, unbalanced nutrient ratios, and insufficient application of micronutrients, urgently requiring the development of targeted corn-specific fertilizer products. Summary of the Invention

[0005] To address the problems existing in the prior art, the purpose of this invention is to provide a corn-specific blended fertilizer and its preparation method.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a corn-specific blended fertilizer, which, by weight, comprises: 20-40 parts of a loaded coated fertilizer and 60-80 parts of an inorganic compound fertilizer.

[0008] Among them, the loaded coated fertilizer is obtained by coating urea with an active coating material; the inorganic compound fertilizer is prepared by first spraying the compound fertilizer granules with a natural adhesive, and then coating them with zinc sulfate monohydrate.

[0009] Preferably, in the preparation process of the active coating material, the mass ratio of isocyanate, vegetable oil polyol, modified polyaspartic acid, synergist, inhibitor and emulsifier is 2.2-3:8.3-12.5:1-3:1-2:0.5-1.5:1-2.

[0010] Preferably, the isocyanate is one of isophorone diisocyanate and diphenylmethane diisocyanate.

[0011] Preferably, the vegetable oil polyol is one or more of castor oil polyol, soybean oil polyol, and palm oil polyol.

[0012] Preferably, the synergist is one or more of alginic acid, fulvic acid, astaxanthin, and chitosan.

[0013] Preferably, the inhibitor is one or more of n-butylthiophosphoric triamine and 3,4-dimethylpyrazole phosphate.

[0014] Preferably, the emulsifier is one or more of polysorbate-80, polyethylene glycol-200, and polyglycerol-10.

[0015] Preferably, in the preparation process of the inorganic compound fertilizer, the mass ratio of compound fertilizer granules, natural adhesive, and zinc sulfate monohydrate is 90-99:0.5-5:0.5-5.

[0016] Preferably, the natural adhesive is one or more of starch-based adhesives, cellulose-based adhesives, and natural resin-based adhesives. More preferably, it is cassava starch adhesive, which can be any commercially available adhesive, such as the Zhongtai TGE series.

[0017] Preferably, the compound fertilizer granules are prepared by mixing ammonium chloride, monoammonium phosphate, and potassium chloride in a mass ratio of 5-10:1-5:1-5 and then granulating.

[0018] Preferably, in the preparation process of the loaded coated fertilizer, the mass ratio of active coating material to urea is 5-15:85-95.

[0019] Preferably, the method for preparing the modified polyaspartic acid includes:

[0020] S1. Weigh ammonium carbonate and sodium 2-aminoethanesulfonate and dissolve them in deionized water. Then add maleic anhydride and mix thoroughly. Microwave treat to obtain an intermediate. Then add sodium hydroxide solution and continue microwave treatment. After adjusting the pH to 2-3, pour into ethanol to collect the precipitate and vacuum dry to obtain sulfonic acid polyaspartic acid.

[0021] S2. Mix thionyl chloride and tetrahydrofuran thoroughly, then add sulfonyl polyaspartic acid, and stir under reflux for 2-6 hours. After the treatment is completed, reduce the pressure and dry completely to obtain sulfonyl chloride polyaspartic acid.

[0022] S3. Add sulfonyl chloride polyaspartic acid and 5-aminolevulinic acid to tetrahydrofuran, stir thoroughly, add triethylamine dropwise, and stir the reaction at room temperature for 2-8 hours. After the reaction is completed, reduce the pressure to dry completely to obtain modified polyaspartic acid.

[0023] Preferably, in S1, the mass ratio of maleic anhydride, ammonium carbonate, sodium 2-aminoethanesulfonate, deionized water, and sodium hydroxide solution is 8-12:4-8:6.2-8.6:15-25:20-30.

[0024] Preferably, in S1, the concentration of the sodium hydroxide solution is 1-3 mol / L.

[0025] Preferably, in step S1, when preparing the intermediate, the microwave power is 250-450W and the microwave time is 2-8min; after adding the sodium hydroxide solution, the microwave power is 250-450W and the microwave time is 3-10min.

[0026] Preferably, in S2, the mass ratio of sulfonic acid polyaspartic acid, sulfoxide, and tetrahydrofuran is 1:2-5:5-10.

[0027] Preferably, in S3, the mass ratio of sulfonyl chloride polyaspartic acid, 5-aminolevulinic acid and tetrahydrofuran is 1:1.3-1.8:10-20.

[0028] Secondly, the present invention provides a method for preparing a corn-specific blended fertilizer, comprising the following steps:

[0029] Step 1. Add modified polyaspartic acid and emulsifier to deionized water to obtain solution A; dissolve the synergist in acetic acid to obtain solution B;

[0030] Step 2. Add the inhibitor to solution A and stir until homogeneous. Then add solution B and stir at room temperature. After stirring, centrifuge the system at low temperature and high speed to remove the supernatant. Freeze-dry the precipitate to prepare particle material containing the inhibitor.

[0031] Step 3. Mix vegetable oil polyol, isocyanate and particle material containing inhibitor to obtain active coating material. Then preheat urea particles, add active coating material, and after film formation, obtain loaded coated fertilizer.

[0032] Step 4. Take compound fertilizer granules, spray cassava starch adhesive on the surface of the compound fertilizer granules, then coat the surface of the fertilizer granules with zinc sulfate monohydrate coated with starch adhesive, and dry to obtain inorganic compound fertilizer.

[0033] Step 5. The loaded coated fertilizer obtained in Step 3 and the inorganic compound fertilizer obtained in Step 4 are mixed to obtain the corn-specific blended fertilizer.

[0034] The beneficial effects of this invention are as follows:

[0035] 1. The corn-specific blended fertilizer provided by this invention uses urea granules as the nutrient core and is coated with a plant oil polyol-based polyurethane coating material. This can improve and reduce the release rate of nitrogen nutrients, ensuring the supply of nitrogen nutrients throughout the corn's growth cycle. By adding modified polyaspartic acid, inhibitors, synergists, and other components to the coating material, the effects of factors such as pH and nutrient ions on the effectiveness of fertilizer inhibitors during fertilizer production can be avoided, further improving nitrogen fertilizer utilization and reducing greenhouse gas emissions.

[0036] 2. The inorganic compound fertilizer in the corn-specific blended fertilizer provided by this invention uses compound fertilizer granules as the nutrient core, and sprays a low-cost and environmentally friendly cassava starch adhesive on the surface, followed by coating with zinc sulfate monohydrate. This avoids the precipitation reaction of zinc and phosphate ions during fertilizer production, which reduces the effectiveness of nutrients and ensures the supply of zinc nutrients throughout the corn's growth cycle.

[0037] 3. This invention uses modified polyaspartic acid, which combines sulfonic acid-based polyaspartic acid and 5-aminolevulinic acid, as a coating modifier for loaded coated fertilizers. When used in combination with inhibitors and synergists, it can not only reduce the influence of pH and nutrient ion concentration on inhibitor activity during fertilizer production, but also promote the absorption of nutrients by plants.

[0038] 4. In addition to polyaspartic acid, modified polyaspartic acid also contains sulfonyl groups, acetylpropionic acid groups and other groups. When used as a coating material for slow-release fertilizers, it can improve the fertilizer's water resistance and controlled-release effect.

[0039] 5. The corn-specific blended fertilizer provided by this invention blends loaded coated fertilizer and inorganic compound fertilizer to provide a long-term supply of macronutrients nitrogen, phosphorus, potassium and micronutrient zinc during corn growth, thereby improving corn quality and increasing yield. Detailed Implementation

[0040] The technical solution of the present invention is illustrated below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or defining the scope of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0041] To better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0042] The present invention will be further described below with reference to the following embodiments.

[0043] Example 1

[0044] A corn-specific blended fertilizer, by weight, comprises: 30 parts of loaded coated fertilizer and 70 parts of inorganic compound fertilizer.

[0045] The inorganic compound fertilizer is prepared by first spraying compound fertilizer granules with a natural adhesive, and then coating them with zinc sulfate monohydrate. In the preparation process, the mass ratio of compound fertilizer granules, natural adhesive, and zinc sulfate monohydrate is 98:1:1. The natural adhesive is cassava starch adhesive (Zhongtai TGE-75); the compound fertilizer granules are prepared by granulation of ammonium chloride, monoammonium phosphate, and potassium chloride in a mass ratio of 8:2:1.

[0046] Among them, the loaded coated fertilizer is obtained by coating urea with an active coating material, with a mass ratio of active coating material to urea of ​​10:90. The components of the active coating material include: isocyanate (isophorone diisocyanate); vegetable oil polyol (castor oil polyol with a hydroxyl value of 206 mg KOH / g and an acid value ≤4 mg KOH / g); synergist (alginic acid); inhibitor (n-butylthiophosphoric triamine); and emulsifier (polysorbate-80).

[0047] The preparation methods of modified polyaspartic acid include:

[0048] S1. Weigh 6g of ammonium carbonate and 7.4g of sodium 2-aminoethanesulfonate and dissolve them in 20g of deionized water. Then add 10g of maleic anhydride, mix thoroughly, and treat under microwave conditions. The microwave power is 350W and the microwave time is 5min. After the treatment, an intermediate is obtained. Then add 25g of 2mol / L sodium hydroxide solution, stir evenly, and continue to treat under microwave conditions. The microwave power is 350W and the microwave time is 8min. After adjusting the pH to 2-3 by adding 36% concentrated hydrochloric acid, pour it into twice the volume of ethanol to precipitate. Collect the precipitate, dry it under vacuum, and obtain sulfonic acid polyaspartic acid.

[0049] S2. Mix 3g of thionyl chloride (SOCl2) and 8g of tetrahydrofuran (THF) thoroughly, then add 1g of sulfonyl polyaspartic acid, stir under reflux for 4h, and after treatment, reduce the pressure to dry completely to obtain sulfonyl chloride polyaspartic acid.

[0050] S3. Add 1g of sulfonyl chloride polyaspartic acid and 1.5g of 5-aminolevulinic acid to 15g of tetrahydrofuran, stir thoroughly, add triethylamine dropwise, stir and react at room temperature for 5h. After the reaction is completed, reduce the pressure to dry completely to obtain modified polyaspartic acid.

[0051] The preparation method of the above-mentioned corn-specific blended fertilizer includes the following steps:

[0052] Step 1. Add 2g of modified polyaspartic acid and 1.5g of emulsifier to deionized water to obtain solution A; dissolve the synergist in acetic acid to obtain solution B;

[0053] Step 2. Add 1g of inhibitor to solution A and stir well. Then add solution B and stir at 500rpm for 2h at room temperature. After stirring, centrifuge the system at low temperature and high speed to remove the supernatant. Freeze-dry the precipitate to prepare particle material containing inhibitor.

[0054] Step 3. Mix 2.8g of vegetable oil polyol, 10.6g of isocyanate and particle material containing inhibitor to obtain active coating material. Then preheat urea particles to 70℃, add active coating material, stir at 70℃ for 20min, and after film formation, obtain loaded coated fertilizer.

[0055] Step 4. Take compound fertilizer granules, spray cassava starch adhesive on the surface of the compound fertilizer granules, then coat the surface of the fertilizer granules with zinc sulfate monohydrate coated with starch adhesive, and dry to obtain inorganic compound fertilizer.

[0056] Step 5. The loaded coated fertilizer obtained in Step 3 and the inorganic compound fertilizer obtained in Step 4 are mixed to obtain a corn-specific blended fertilizer.

[0057] Example 2

[0058] A corn-specific blended fertilizer differs from Example 1 only in the ratio of the loaded coated fertilizer and the inorganic compound fertilizer. By weight, the components include: 20 parts of the loaded coated fertilizer and 80 parts of the inorganic compound fertilizer.

[0059] Example 3

[0060] A corn-specific blended fertilizer differs from Example 1 only in the ratio of the loaded coated fertilizer and the inorganic compound fertilizer. By weight, the composition includes: 40 parts loaded coated fertilizer and 60 parts inorganic compound fertilizer.

[0061] Example 4

[0062] A corn-specific blended fertilizer, by weight, comprises: 30 parts of loaded coated fertilizer and 70 parts of inorganic compound fertilizer.

[0063] The inorganic compound fertilizer is prepared by first spraying compound fertilizer granules with a natural adhesive, and then coating them with zinc sulfate monohydrate. In the preparation process, the mass ratio of compound fertilizer granules, natural adhesive, and zinc sulfate monohydrate is 90:5:5. The natural adhesive is a cellulose-based adhesive; the compound fertilizer granules are prepared by granulation of ammonium chloride, monoammonium phosphate, and potassium chloride in a mass ratio of 5:1:1.

[0064] Among them, the loaded coated fertilizer is obtained by coating urea with an active coating material, with a mass ratio of active coating material to urea of ​​5:95. The components of the active coating material include: isocyanate diphenylmethane diisocyanate; vegetable oil polyol soybean oil polyol; synergist humic acid; inhibitor 3,4-dimethylpyrazole phosphate; and emulsifier polyethylene glycol-200.

[0065] The preparation methods of modified polyaspartic acid include:

[0066] S1. Weigh 4g of ammonium carbonate and 6.2g of sodium 2-aminoethanesulfonate and dissolve them in 15g of deionized water. Then add 8g of maleic anhydride, mix thoroughly, and treat under microwave conditions. The microwave power is 250W and the microwave time is 2min. After the treatment, an intermediate is obtained. Then add 20g of 1mol / L sodium hydroxide solution, stir evenly, and continue to treat under microwave conditions. The microwave power is 250W and the microwave time is 3min. After adjusting the pH to 2-3 by adding 36% concentrated hydrochloric acid, pour it into twice the volume of ethanol to precipitate. Collect the precipitate, dry it under vacuum, and obtain sulfonic acid polyaspartic acid.

[0067] S2. Mix 2g of sulfonyl chloride (SOCl2) and 5g of tetrahydrofuran (THF) thoroughly, then add 1g of sulfonyl polyaspartic acid, stir under reflux for 2h, and after treatment, reduce the pressure to dry completely to obtain sulfonyl chloride polyaspartic acid.

[0068] S3. Add 1g of sulfonyl chloride polyaspartic acid and 1.3g of 5-aminolevulinic acid to 10g of tetrahydrofuran, stir thoroughly, add triethylamine dropwise, stir and react at room temperature for 2h. After the reaction is completed, reduce the pressure to dry completely to obtain modified polyaspartic acid.

[0069] The preparation method of the above-mentioned corn-specific blended fertilizer includes the following steps:

[0070] Step 1. Add 1g of modified polyaspartic acid and 1g of emulsifier to deionized water to obtain solution A; dissolve the synergist in acetic acid to obtain solution B;

[0071] Step 2. Add 0.5g of inhibitor to solution A and stir well. Then add solution B and stir at 500rpm for 2 hours at room temperature. After stirring, centrifuge the system at low temperature and high speed to remove the supernatant. Freeze-dry the precipitate to prepare particle material containing inhibitor.

[0072] Step 3. Mix 8.3g of vegetable oil polyol, 2.2g of isocyanate and particle material containing inhibitor to obtain active coating material. Then preheat urea particles to 70°C, add active coating material, stir at 70°C for 15 minutes, and after film formation, obtain loaded coated fertilizer.

[0073] Step 4. Take compound fertilizer granules, spray cassava starch adhesive on the surface of the compound fertilizer granules, then coat the surface of the fertilizer granules with zinc sulfate monohydrate coated with starch adhesive, and dry to obtain inorganic compound fertilizer.

[0074] Step 5. The loaded coated fertilizer obtained in Step 3 and the inorganic compound fertilizer obtained in Step 4 are mixed to obtain a corn-specific blended fertilizer.

[0075] Example 5

[0076] A corn-specific blended fertilizer, by weight, comprises: 30 parts of loaded coated fertilizer and 70 parts of inorganic compound fertilizer.

[0077] The inorganic compound fertilizer is prepared by first spraying compound fertilizer granules with a natural adhesive, and then coating them with zinc sulfate monohydrate. In the preparation process, the mass ratio of compound fertilizer granules, natural adhesive, and zinc sulfate monohydrate is 99:0.5:0.5. The natural adhesive is a natural resin-based adhesive; the compound fertilizer granules are prepared by granulation of ammonium chloride, monoammonium phosphate, and potassium chloride in a mass ratio of 10:5:5.

[0078] Among them, the loaded coated fertilizer is obtained by coating urea with an active coating material, with a mass ratio of active coating material to urea of ​​15:85. The components of the active coating material include isophorone diisocyanate; palm oil polyol; chitosan as a synergist; 3,4-dimethylpyrazole phosphate as an inhibitor; and polyglycerol-10 as an emulsifier.

[0079] The preparation methods of modified polyaspartic acid include:

[0080] S1. Weigh 8g of ammonium carbonate and 8.6g of sodium 2-aminoethanesulfonate and dissolve them in 25g of deionized water. Then add 12g of maleic anhydride and mix thoroughly. Place the mixture under microwave conditions with a power of 450W and a time of 8min. After the treatment, an intermediate is obtained. Then add 30g of 3mol / L sodium hydroxide solution and stir evenly. Continue to place the mixture under microwave conditions with a power of 450W and a time of 10min. Adjust the pH to 2-3 by adding 36% concentrated hydrochloric acid. Pour the mixture into twice the volume of ethanol to precipitate the precipitate. Collect the precipitate and dry it under vacuum to obtain sulfonic acid polyaspartic acid.

[0081] S2. Mix 5g of thionyl chloride (SOCl2) and 10g of tetrahydrofuran (THF) thoroughly, then add 1g of sulfonyl polyaspartic acid, stir under reflux for 6h, and after treatment, reduce the pressure to dry completely to obtain sulfonyl chloride polyaspartic acid.

[0082] S3. Add 1g of sulfonyl chloride polyaspartic acid and 1.8g of 5-aminolevulinic acid to 20g of tetrahydrofuran. After stirring thoroughly, add triethylamine dropwise and stir the mixture at room temperature for 8 hours. After the reaction is complete, reduce the pressure and dry completely to obtain modified polyaspartic acid.

[0083] The preparation method of the above-mentioned corn-specific blended fertilizer includes the following steps:

[0084] Step 1. Add 3g of modified polyaspartic acid and 2g of emulsifier to deionized water to obtain solution A; dissolve the synergist in acetic acid to obtain solution B;

[0085] Step 2. Add 1.5g of inhibitor to solution A and stir well. Then add solution B and stir at 500rpm for 2 hours at room temperature. After stirring, centrifuge the system at low temperature and high speed to remove the supernatant. Freeze-dry the precipitate to prepare particle material containing inhibitor.

[0086] Step 3. Mix 12.5g of vegetable oil polyol, 3g of isocyanate and particle material containing inhibitor to obtain active coating material. Then preheat urea particles to 70°C, add active coating material, stir at 70°C for 30 minutes, and after film formation, obtain loaded coated fertilizer.

[0087] Step 4. Take compound fertilizer granules, spray cassava starch adhesive on the surface of the compound fertilizer granules, then coat the surface of the fertilizer granules with zinc sulfate monohydrate coated with starch adhesive, and dry to obtain inorganic compound fertilizer.

[0088] Step 5. The loaded coated fertilizer obtained in Step 3 and the inorganic compound fertilizer obtained in Step 4 are mixed to obtain a corn-specific blended fertilizer.

[0089] Comparative Example 1

[0090] A corn blended fertilizer, by weight, comprises 30 parts coated fertilizer and 70 parts compound fertilizer; wherein the coated fertilizer is commercially available unloaded plant oil-based polyurethane coated urea, and the compound fertilizer is prepared by granulation of ammonium chloride, monoammonium phosphate, potassium chloride, and zinc sulfate monohydrate.

[0091] Comparative Example 2

[0092] A corn blended fertilizer, by weight, comprises 30 parts of a loaded coated fertilizer and 70 parts of a compound fertilizer; wherein the compound fertilizer is prepared by granulation of ammonium chloride, monoammonium phosphate, potassium chloride, and zinc sulfate monohydrate; and the modified polyaspartic acid in the coated fertilizer is replaced with polyaspartic acid. The preparation specifically includes the following steps:

[0093] 2g of polyaspartic acid and 1.5g of polysorbate-80 were added to deionized water to obtain solution A; alginate was dissolved in acetic acid to obtain solution B; 1g of n-butylthiophosphoric triamine was added to solution A and stirred evenly, and then solution B was added. The mixture was stirred at 500 rpm for 2 hours at room temperature. After stirring, the system was centrifuged at low temperature and high speed to remove the supernatant. The precipitate was freeze-dried to prepare particle material containing inhibitor.

[0094] Step 3. Mix 2.8g castor oil polyol, 10.6g isophorone diisocyanate and particle material containing inhibitor to obtain active coating material. Then preheat urea particles to 70℃, add active coating material, stir at 70℃ for 20min, and after film formation, obtain loaded coated fertilizer.

[0095] Comparative Example 3

[0096] Farmers commonly use 28-6-6 urea-based compound fertilizer.

[0097] Experimental testing

[0098] The experimental site was selected in a maize-growing area in Kaifeng, Henan Province. The basic physicochemical properties of the soil were: pH = 7.92, organic matter content 2.53%, available nitrogen 90.56 mg / kg, available phosphorus 23.28 mg / kg, and available potassium 104.66 mg / kg. A randomized block design was used, with a plot area of ​​72 m². 2 The planting density was 4500 plants / mu, and the maize variety was 'Zhengdan 958'. There were 6 treatments in this experiment, namely Examples 1-3 and Comparative Examples 1-3. The fertilizer application rate was 45 kg / mu. Except for the type of fertilizer, the other field measures such as sowing, irrigation and weeding were the same.

[0099] During the corn maturity period, the corn stalk diameter and leaf area were measured. After the corn was harvested, the ear length, ear diameter, number of kernels per ear, thousand-kernel weight and yield were measured. At the same time, the nitrogen fertilizer utilization rate of the planting area was calculated. Greenhouse gas samples were collected and measured using the static chamber-gas chromatography method. The collected gases were brought back to the laboratory on the same day and the N2O concentration was measured using a gas chromatography instrument.

[0100] From the agronomic traits of maize in Table 1, compared with ordinary coated urea and compound fertilizer with added zinc sulfate monohydrate (Comparative Example 1), compound fertilizer with added 3,4-dimethylpyrazole phosphate and polyaspartic acid and coated with added zinc sulfate monohydrate (Comparative Example 2), and farmers' conventional fertilization (Comparative Example 3), the application of the maize-specific blended fertilizer of the present invention increased the ear length, ear diameter, stem diameter and leaf area of ​​maize (Table 1).

[0101] Table 1 Effects of different treatments on agronomic traits of maize

[0102]

[0103] As shown in Table 2, compared with ordinary coated urea and compound fertilizer with added zinc sulfate monohydrate (Comparative Example 1), compound fertilizer with added 3,4-dimethylpyrazole phosphate and polyaspartic acid and coated with added zinc sulfate monohydrate (Comparative Example 2), and farmers' conventional fertilization (Comparative Example 3), the application of the corn-specific blended fertilizer of this invention increased the number of grains per ear, the thousand-grain weight, and the yield of corn. Among them, the yield increase reached 15.54%-17.75% compared with farmers' conventional fertilization.

[0104] Table 2. Effects of different treatments on maize yield and yield factors.

[0105]

[0106] As shown in Table 3, the nitrogen fertilizer utilization rate after applying the corn-specific blended fertilizer of the present invention is 31.55%-35.08%, which is significantly higher than that of ordinary coated urea and compound fertilizer with added zinc sulfate monohydrate (Comparative Example 1), compound fertilizer with added 3,4-dimethylpyrazole phosphate and polyaspartic acid and added zinc sulfate monohydrate (Comparative Example 2), and the fertilizer commonly used by farmers (Comparative Example 3).

[0107] Table 3 Effects of different treatments on nitrogen fertilizer utilization rate in maize

[0108]

[0109] As shown in Table 4, the N2O emissions during the corn growing season are significantly reduced after applying the corn-specific blended fertilizer of this invention.

[0110] Table 4. Impact of different treatments on cumulative total greenhouse gas N2O emissions.

[0111]

[0112] In summary, the corn-specific blended fertilizer provided by this invention can improve the agronomic traits and yield indicators of corn, increase nitrogen fertilizer utilization, and reduce greenhouse gas N2O emissions.

[0113] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0114] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A corn-specific blended fertilizer, characterized in that, The ingredients, calculated by weight, include: 20-40 parts of loaded coated fertilizer and 60-80 parts of inorganic compound fertilizer. Loaded coated fertilizers are obtained by coating urea with active coating materials; inorganic compound fertilizers are prepared by first spraying compound fertilizer granules with natural adhesives, and then coating them with zinc sulfate monohydrate. In the preparation of the active coating material, the mass ratio of isocyanate, vegetable oil polyol, modified polyaspartic acid, synergist, inhibitor and emulsifier is 2.2-3:8.3-12.5:1-3:1-2:0.5-1.5:1-2. The isocyanate is one of isophorone diisocyanate and diphenylmethane diisocyanate; the vegetable oil polyol is one or more of castor oil polyol, soybean oil polyol, and palm oil polyol. The inhibitor is one or more of n-butylthiophosphoric triamine and 3,4-dimethylpyrazole phosphate; The method for preparing the modified polyaspartic acid includes: S1. Weigh ammonium carbonate and sodium 2-aminoethanesulfonate and dissolve them in deionized water. Then add maleic anhydride and mix thoroughly. Microwave treat to obtain an intermediate. Then add sodium hydroxide solution and continue microwave treatment. After adjusting the pH to 2-3, pour into ethanol to collect the precipitate and vacuum dry to obtain sulfonic acid polyaspartic acid. S2. Mix thionyl chloride and tetrahydrofuran thoroughly, then add sulfonyl polyaspartic acid, and stir under reflux for 2-6 hours. After the treatment is completed, reduce the pressure and dry completely to obtain sulfonyl chloride polyaspartic acid. S3. Add sulfonyl chloride polyaspartic acid and 5-aminolevulinic acid to tetrahydrofuran, stir thoroughly, add triethylamine dropwise, and stir the reaction at room temperature for 2-8 hours. After the reaction is completed, reduce the pressure to dry completely to obtain modified polyaspartic acid.

2. The corn-specific blended fertilizer according to claim 1, characterized in that, The synergist is one or more of alginic acid, fulvic acid, astaxanthin, and chitosan; the emulsifier is one or more of polysorbate-80, polyethylene glycol-200, and polyglycerol-10.

3. The corn-specific blended fertilizer according to claim 1, characterized in that, In the preparation process of the inorganic compound fertilizer, the mass ratio of compound fertilizer granules, natural adhesive, and zinc sulfate monohydrate is 90-99:0.5-5:0.5-5; the compound fertilizer granules are prepared by granulation after mixing ammonium chloride, monoammonium phosphate, and potassium chloride in a mass ratio of 5-10:1-5:1-5.

4. A corn-specific blended fertilizer according to claim 3, characterized in that, The natural adhesive is one or more of starch-based adhesives, cellulose-based adhesives, and natural resin-based adhesives.

5. A corn-specific blended fertilizer according to claim 1, characterized in that, In the preparation process of the loaded coated fertilizer, the mass ratio of active coating material to urea is 5-15:85-95.

6. A corn-specific blended fertilizer according to claim 1, characterized in that, In S1, the mass ratio of maleic anhydride, ammonium carbonate, sodium 2-aminoethanesulfonate, deionized water, and sodium hydroxide solution is 8-12:4-8:6.2-8.6:15-25:20-30.

7. A corn-specific blended fertilizer according to claim 1, characterized in that, In S2, the mass ratio of sulfonic acid polyaspartic acid, sulfoxide, and tetrahydrofuran is 1:2-5:5-10.

8. A corn-specific blended fertilizer according to claim 1, characterized in that, In S3, the mass ratio of sulfonyl chloride polyaspartic acid, 5-aminolevulinic acid and tetrahydrofuran is 1:1.3-1.8:10-20.

9. A method for preparing the corn-specific blended fertilizer according to claim 1, characterized in that, Includes the following steps: Step 1. Add modified polyaspartic acid and emulsifier to deionized water to obtain solution A; dissolve the synergist in acetic acid to obtain solution B; Step 2. Add the inhibitor to solution A and stir until homogeneous. Then add solution B and stir at room temperature. After stirring, centrifuge the system at low temperature and high speed to remove the supernatant. Freeze-dry the precipitate to prepare particle material containing the inhibitor. Step 3. Mix vegetable oil polyol, isocyanate and particle material containing inhibitor to obtain active coating material. Then preheat urea particles, add active coating material, and after film formation, obtain loaded coated fertilizer. Step 4. Take compound fertilizer granules, spray cassava starch adhesive on the surface of the compound fertilizer granules, then coat the surface of the fertilizer granules with zinc sulfate monohydrate coated with starch adhesive, and dry to obtain inorganic compound fertilizer. Step 5. The loaded coated fertilizer obtained in Step 3 and the inorganic compound fertilizer obtained in Step 4 are mixed to obtain the corn-specific blended fertilizer.

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