Special blended fertilizer for corn and preparation method thereof

Abstract

The invention relates to the field of fertilizers, in particular to a special blended fertilizer for corn and a preparation method thereof, and the special blended fertilizer for corn comprises the following components in parts by weight: 20-40 parts of a supported coated fertilizer and 60-80 parts of an inorganic compound fertilizer. According to the special bulk blending fertilizer for corn, the urea particles serve as nutrient cores, the urea particles are wrapped with the vegetable oil polyol-based polyurethane coating material, the release rate of nitrogen nutrients can be increased and reduced, nitrogen nutrient supply in the whole growth cycle of corn is guaranteed, and the yield of the corn is increased. By adding the modified polyaspartic acid, the inhibitor, the synergist and other components into the coating material, the influence of pH, nutrient ions and other factors on the effectiveness of the fertilizer inhibitor in the fertilizer production process can be avoided, the nitrogen fertilizer utilization rate is further increased, and greenhouse gas emission is reduced.

Description

Technical Field

[0001] The invention relates to the field of fertilizers, and in particular to a special blended fertilizer for corn and a preparation method thereof. Background Art

[0002] At present, the main measures to reduce nitrogen fertilizer emissions from farmland include applying stable fertilizers and promoting the application of emission reduction technical measures. In actual production, the application of emission reduction technical measures often requires growers to master certain professional knowledge and skills, which is difficult to promote. Therefore, stable fertilizers that are easy to apply are more popular with growers. The core of stable fertilizers lies in fertilizer inhibitors. During the production process, fertilizer inhibitors are easily affected by factors such as temperature, pH, and nutrient ions in the fertilizer production process, which reduces the effectiveness of inhibitors in the finished product and affects the terminal application effect.

[0003] In agricultural production, high-intensity planting activities will lead to the deterioration of soil properties and limited crop yield increases. The targeted application of medium and trace element fertilizers can not only improve the inorganic nutritional balance of crops and increase crop yields, but also improve the quality of agricultural products. At present, many fertilizer products on the market add trace elements through internal addition, but in the production process, medium and trace element ions represented by zinc will react with phosphate to form precipitation, affecting the effectiveness of the elements.

[0004] Corn is one of the three major staple crops in my country and plays an important role in ensuring national food security. In the process of corn planting, fertilization is one of the most important agricultural production measures. In order to achieve high yields, it is necessary to ensure nutrient supply during the growth cycle, especially during the fruiting period. At present, there are common problems in corn fertilization in my country, such as excessive nitrogen fertilizer application, unbalanced nutrient ratio, and insufficient application of trace elements. There is an urgent need to develop targeted corn-specific fertilizer products. Summary of the invention

[0005] In view of the problems existing in the prior art, the object of the present invention is to provide a special blended fertilizer for corn and a preparation method thereof.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] In a first aspect, the present invention provides a special blended fertilizer for corn, which comprises, by weight, 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 active coating materials; the inorganic compound fertilizer is prepared by first spraying compound fertilizer particles with natural adhesives and then wrapping 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 triamide 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 the compound fertilizer particles, the 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 adhesive, cellulose adhesive, and natural resin adhesive. More preferably, it is cassava starch adhesive among starch adhesives. The adhesive can be any adhesive available on the market, such as Zhongtai TGE series.

[0017] Preferably, the compound fertilizer particles 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, during the preparation of the loaded coated fertilizer, the mass ratio of the active coating material to urea is 5-15:85-95.

[0019] Preferably, the preparation method of the modified polyaspartic acid comprises:

[0020] S1, weighing ammonium carbonate and sodium 2-aminoethanesulfonate and dissolving them in deionized water, then adding maleic anhydride, mixing thoroughly, and subjecting to microwave treatment to obtain an intermediate, then adding sodium hydroxide solution, continuing microwave treatment, and then adjusting the pH to 2-3, pouring into ethanol to collect the precipitate, and vacuum drying to obtain sulfonic acid polyaspartic acid;

[0021] S2, fully mixing thionyl chloride and tetrahydrofuran, then adding sulfonic acid polyaspartic acid, stirring and treating under reflux conditions for 2-6 hours, and after the treatment, reducing the pressure to completely dryness to obtain sulfonyl chloride polyaspartic acid;

[0022] S3. Add sulfonyl chloride polyaspartic acid and 5-aminolevulinic acid into tetrahydrofuran, stir well, then drop triethylamine, stir and react at room temperature for 2-8 hours. After the reaction is completed, reduce the pressure to complete dryness 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 S1, when preparing the intermediate, the microwave power is 250-450 W, and the microwave time is 2-8 min; after adding the sodium hydroxide solution, the microwave power is 250-450 W, and the microwave time is 3-10 min.

[0026] Preferably, in S2, the mass ratio of sulfonic polyaspartic acid, thionyl chloride 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] In a second aspect, the present invention provides a method for preparing a special blended fertilizer for corn, comprising the following steps:

[0029] Step 1. Add modified polyaspartic acid and emulsifier into 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 evenly, then add solution B and stir at room temperature. After stirring, centrifuge the system at low temperature and high speed, remove the supernatant, freeze-dry the precipitate, and prepare a particle material containing the inhibitor;

[0031] Step 3. Mixing the vegetable oil polyol, isocyanate and the particle material containing the inhibitor to obtain the active coating material, then preheating the urea particles, adding the active coating material, and forming a film to obtain a loaded coated fertilizer;

[0032] Step 4. Take compound fertilizer particles, spray cassava starch adhesive on the surface of the compound fertilizer particles, then wrap zinc sulfate monohydrate on the surface of the fertilizer particles sprayed with starch adhesive, and obtain inorganic compound fertilizer after drying;

[0033] Step 5. The loaded coated fertilizer obtained in step 3 and the inorganic compound fertilizer obtained in step 4 are blended to obtain the special blended fertilizer for corn.

[0034] The beneficial effects of the present invention are:

[0035] 1. The loaded coated fertilizer in the special blended fertilizer for corn provided by the present invention uses urea granules as the nutrient core and is coated with a vegetable oil polyol-based polyurethane coating material on the outside, which can increase and reduce the release rate of nitrogen nutrients and ensure the nitrogen nutrient supply throughout the growth cycle of corn. By adding modified polyaspartic acid, inhibitors, synergists and other ingredients to the coating material, the influence of factors such as pH and nutrient ions on the effectiveness of fertilizer inhibitors during the fertilizer production process can be avoided, thereby further improving the utilization rate of nitrogen fertilizers and reducing greenhouse gas emissions.

[0036] 2. The inorganic compound fertilizer in the corn-specific blended fertilizer provided by the present invention uses compound fertilizer particles as the nutrient core, sprays a low-cost environmentally friendly material cassava starch adhesive on the surface, and then wraps zinc sulfate monohydrate to avoid the precipitation reaction of zinc and phosphate ions during the fertilizer production process to reduce nutrient effectiveness, thereby ensuring the zinc nutrient supply throughout the growth cycle of corn.

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

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

[0039] 5. The special blended fertilizer for corn provided by the present invention blends the loaded coated fertilizer and the inorganic compound fertilizer, and supplies the macro-elements nitrogen, phosphorus, potassium and trace element zinc in the growth process of corn in a long-term manner, which can improve the quality of corn and increase the yield. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0041] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although 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 by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0042] The present invention will be further described below in conjunction with the following examples.

[0043] Example 1

[0044] A special blended fertilizer for corn, comprising, by weight, 30 parts of loaded coated fertilizer and 70 parts of inorganic compound fertilizer.

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

[0046] The loaded coated fertilizer is obtained by coating urea with an active coating material, and the mass ratio of the active coating material to urea is 10:90. Among the ingredients for preparing the active coating material, the isocyanate is isophorone diisocyanate; the vegetable oil polyol is castor oil polyol (hydroxyl value is 206 mgKOH / g, acid value ≤4 mgKOH / g); the synergist is alginic acid; the inhibitor is n-butyl thiophosphoric acid triamide; and the emulsifier is polysorbate-80.

[0047] Wherein, the preparation method of modified polyaspartic acid comprises:

[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, the microwave time is 5min, and the intermediate is obtained after the treatment, and then 25g of 2mol / L sodium hydroxide solution is added, stirred evenly, and then treated under microwave conditions, the microwave power is 350W, the microwave time is 8min, 36% concentrated hydrochloric acid is added dropwise to adjust the pH to 2-3, and then poured into twice the volume of ethanol for precipitation, the precipitate is collected, and vacuum dried to obtain sulfonic acid polyaspartic acid;

[0049] S2, 3g of thionyl chloride (SOCl2) and 8g of tetrahydrofuran (THF) were fully mixed, and then 1g of sulfonic acid polyaspartic acid was added, and stirred for 4h under reflux conditions. After the treatment, the pressure was reduced to complete dryness to obtain sulfonyl chloride polyaspartic acid;

[0050] S3. Add 1 g of sulfonyl chloride polyaspartic acid and 1.5 g of 5-aminolevulinic acid to 15 g of tetrahydrofuran, stir well, then drop triethylamine, stir and react at room temperature for 5 h. After the reaction is completed, reduce the pressure to complete dryness to obtain modified polyaspartic acid.

[0051] The preparation method of the above-mentioned special blended fertilizer for corn comprises the following steps:

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

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

[0054] Step 3. 2.8 g of vegetable oil polyol, 10.6 g of isocyanate and a particle material containing an inhibitor are mixed to obtain an active coating material, and then the urea particles are preheated to 70° C., and then the active coating material is added, and stirred at 70° C. for 20 minutes. After film formation, a loaded coated fertilizer is obtained;

[0055] Step 4. Take compound fertilizer particles, spray cassava starch adhesive on the surface of the compound fertilizer particles, then wrap zinc sulfate monohydrate on the surface of the fertilizer particles sprayed with starch adhesive, and obtain inorganic compound fertilizer after drying;

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

[0057] Example 2

[0058] A special blended fertilizer for corn, which differs from Example 1 only in that the ratio of the loaded coated fertilizer to the inorganic compound fertilizer is different. Calculated by weight, the ingredients include: 20 parts of the loaded coated fertilizer and 80 parts of the inorganic compound fertilizer.

[0059] Example 3

[0060] A special blended fertilizer for corn, which differs from Example 1 only in that the ratio of the loaded coated fertilizer to the inorganic compound fertilizer is different. Calculated by weight, the ingredients include: 40 parts of the loaded coated fertilizer and 60 parts of the inorganic compound fertilizer.

[0061] Example 4

[0062] A special blended fertilizer for corn, comprising, by weight, 30 parts of loaded coated fertilizer and 70 parts of inorganic compound fertilizer.

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

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

[0065] Wherein, the preparation method of modified polyaspartic acid comprises:

[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, the microwave time is 2min, and the intermediate is obtained after the treatment, and then 20g of 1mol / L sodium hydroxide solution is added, stirred evenly, and then treated under microwave conditions, the microwave power is 250W, the microwave time is 3min, 36% concentrated hydrochloric acid is added dropwise to adjust the pH to 2-3, and then poured into twice the volume of ethanol for precipitation, the precipitate is collected, and vacuum dried to obtain sulfonic acid polyaspartic acid;

[0067] S2, 2g of thionyl chloride (SOCl2) and 5g of tetrahydrofuran (THF) are fully mixed, and then 1g of sulfonic acid polyaspartic acid is added, and stirred for 2h under reflux conditions. After the treatment, the pressure is reduced to complete dryness to obtain sulfonyl chloride polyaspartic acid;

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

[0069] The preparation method of the above-mentioned special blended fertilizer for corn comprises the following steps:

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

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

[0072] Step 3. 8.3 g of vegetable oil polyol, 2.2 g of isocyanate and a particle material containing an inhibitor are mixed to obtain an active coating material, and then the urea particles are preheated to 70° C., and then the active coating material is added, and stirred at 70° C. for 15 minutes. After film formation, a loaded coated fertilizer is obtained;

[0073] Step 4. Take compound fertilizer particles, spray cassava starch adhesive on the surface of the compound fertilizer particles, then wrap zinc sulfate monohydrate on the surface of the fertilizer particles sprayed with starch adhesive, and obtain inorganic compound fertilizer after drying;

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

[0075] Example 5

[0076] A special blended fertilizer for corn, comprising, by weight, 30 parts of loaded coated fertilizer and 70 parts of inorganic compound fertilizer.

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

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

[0079] Wherein, the preparation method of modified polyaspartic acid comprises:

[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, mix thoroughly, and treat under microwave conditions, the microwave power is 450W, the microwave time is 8min, and the intermediate is obtained after the treatment, and then 30g, 3mol / L sodium hydroxide solution is added, stirred evenly, and then treated under microwave conditions, the microwave power is 450W, the microwave time is 10min, 36% concentrated hydrochloric acid is added dropwise to adjust the pH to 2-3, and then poured into twice the volume of ethanol for precipitation, the precipitate is collected, and vacuum dried to obtain sulfonic acid polyaspartic acid;

[0081] S2, 5g of thionyl chloride (SOCl2) and 10g of tetrahydrofuran (THF) were fully mixed, and then 1g of sulfonic acid polyaspartic acid was added, and stirred under reflux conditions for 6h. After the treatment, the pressure was reduced to complete dryness to obtain sulfonyl chloride polyaspartic acid;

[0082] S3. Add 1 g of sulfonyl chloride polyaspartic acid and 1.8 g of 5-aminolevulinic acid to 20 g of tetrahydrofuran, stir well, then drop triethylamine, stir and react at room temperature for 8 h. After the reaction is completed, reduce the pressure to complete dryness to obtain modified polyaspartic acid.

[0083] The preparation method of the above-mentioned special blended fertilizer for corn comprises the following steps:

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

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

[0086] Step 3. 12.5 g of vegetable oil polyol, 3 g of isocyanate and a particle material containing an inhibitor are mixed to obtain an active coating material, and then the urea particles are preheated to 70° C., and then the active coating material is added, and stirred at 70° C. for 30 minutes. After film formation, a loaded coated fertilizer is obtained;

[0087] Step 4. Take compound fertilizer particles, spray cassava starch adhesive on the surface of the compound fertilizer particles, then wrap zinc sulfate monohydrate on the surface of the fertilizer particles sprayed with starch adhesive, and obtain inorganic compound fertilizer after drying;

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

[0089] Comparative Example 1

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

[0091] Comparative Example 2

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

[0093] 2 g of polyaspartic acid and 1.5 g of polysorbate-80 are added to deionized water to obtain solution A; alginic acid is dissolved in acetic acid to obtain solution B; 1 g of n-butylthiophosphoric triamide is added to solution A, stirred evenly, and then solution B is added, stirred at room temperature at 500 rpm for 2 h, and after stirring, the system is centrifuged at low temperature and high speed, the supernatant is removed, and the precipitate is freeze-dried to prepare a particle material containing an inhibitor;

[0094] Step 3. Mix 2.8 g of castor oil polyol, 10.6 g of isophorone diisocyanate and a particle material containing an inhibitor to obtain an active coating material, then preheat the urea granules to 70° C., then add the active coating material, stir at 70° C. for 20 minutes, and after film formation, obtain a loaded coated fertilizer.

[0095] Comparative Example 3

[0096] Farmers usually use 28-6-6 urea-based compound fertilizer for fertilizer application.

[0097] Experimental testing

[0098] The test site was selected in a corn planting area in Kaifeng, Henan Province. The basic physical and chemical properties of the soil were as follows: pH = 7.92, organic matter content 2.53%, alkaline nitrogen 90.56 mg / kg, available phosphorus 23.28 mg / kg, and available potassium 104.66 mg / kg. The test adopted a randomized block design with a plot area of ​​72 m 2 The planting density is 4500 plants / mu, the corn variety is 'Zhengdan 958', and there are 6 treatments in this test, namely Examples 1-3 and Comparative Examples 1-3. The fertilizer application rate is 45kg / mu. Except for the different types of fertilizers, other field measures such as sowing, irrigation, and weeding are the same.

[0099] The stem diameter and leaf area of ​​corn were measured during the corn maturity period. The ear length, ear diameter, number of grains per ear, 1000-grain weight and yield were measured after the corn was harvested. The nitrogen fertilizer utilization rate of the planting area was calculated at the same time. The static box-meteorological chromatograph method was used for greenhouse gas sample collection and measurement. The collected gas was brought back to the laboratory on the same day and the N2O concentration was determined using a meteorological chromatograph.

[0100] From the agronomic traits of corn in Table 1, compared with the compound fertilizer of ordinary coated urea and zinc sulfate monohydrate (Comparative Example 1), the compound fertilizer coated after adding 3,4-dimethylpyrazole phosphate and polyaspartic acid and zinc sulfate monohydrate (Comparative Example 2), and farmers' usual fertilization (Comparative Example 3), after applying the special blended fertilizer for corn of the present invention, the ear length, ear diameter, stem diameter and leaf area of ​​corn are all improved (Table 1).

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

[0102]

[0103] From the corn yield index in Table 2, compared with the compound fertilizer of ordinary coated urea and zinc sulfate monohydrate (Comparative Example 1), the compound fertilizer coated after adding 3,4-dimethylpyrazole phosphate and polyaspartic acid and zinc sulfate monohydrate (Comparative Example 2), and farmers' conventional fertilization (Comparative Example 3), after applying the special blended fertilizer for corn of the present invention, the number of kernels per ear, the thousand-kernel weight and the yield of corn are all improved, and compared with farmers' conventional fertilization, the yield increase is 15.54%-17.75%.

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

[0105]

[0106] From the nitrogen fertilizer utilization rate in Table 3, after applying the special blended fertilizer for corn of the present invention, the nitrogen fertilizer utilization rate is 31.55%-35.08%, which is significantly higher than the compound fertilizer of ordinary coated urea and zinc sulfate monohydrate (Comparative Example 1), the compound fertilizer coated after adding 3,4-dimethylpyrazole phosphate and polyaspartic acid and zinc sulfate monohydrate (Comparative Example 2), and the conventional fertilization of farmers (Comparative Example 3).

[0107] Table 3 Effects of different treatments on nitrogen fertilizer utilization efficiency of corn

[0108]

[0109] Through the measurement of the greenhouse gas N2O emission during the growth period of corn in Table 4, it can be seen that after applying the special blended fertilizer for corn of the present invention, the N2O emission is significantly reduced.

[0110] Table 4 Effects of different treatments on the total cumulative emissions of greenhouse gas N2O

[0111]

[0112] In summary, the special blended fertilizer for corn provided by the present invention can improve the agronomic traits and yield index of corn, improve the utilization rate of nitrogen fertilizer, and reduce the emission of greenhouse gas N2O.

[0113] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0114] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A special blended fertilizer for corn, characterized in that: Calculated by weight, the ingredients include: 20-40 parts of loaded coated fertilizer, 60-80 parts of inorganic compound fertilizer; The loaded coated fertilizer is obtained by coating urea with an active coating material; the inorganic compound fertilizer is prepared by first spraying compound fertilizer particles with a natural adhesive and then coating them with zinc sulfate monohydrate; Wherein, 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.

2. The special blended fertilizer for corn according to claim 1, characterized in that: 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 synergist is one or more of alginic acid, fulvic acid, astaxanthin and chitosan; the inhibitor is one or more of n-butylthiophosphoric triamide and 3,4-dimethylpyrazole phosphate; the emulsifier is one or more of polysorbate-80, polyethylene glycol-200 and polyglycerol-10.

3. The special blended fertilizer for corn according to claim 1, characterized in that: In the preparation process of the inorganic compound fertilizer, the mass ratio of the compound fertilizer particles, the natural adhesive and the zinc sulfate monohydrate is 90-99:0.5-5:0.5-5; the compound fertilizer particles 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.

4. The special blended fertilizer for corn according to claim 3, characterized in that: The natural adhesive is one or more of starch adhesive, cellulose adhesive and natural resin adhesive.

5. The special blended fertilizer for corn according to claim 1, characterized in that: During the preparation of the loaded coated fertilizer, the mass ratio of the active coating material to urea is 5-15:85-95.

6. The special blended fertilizer for corn according to claim 1, characterized in that: The preparation method of the modified polyaspartic acid comprises: S1, weighing ammonium carbonate and sodium 2-aminoethanesulfonate and dissolving them in deionized water, then adding maleic anhydride, mixing thoroughly, and subjecting to microwave treatment to obtain an intermediate, then adding sodium hydroxide solution, continuing microwave treatment, and then adjusting the pH to 2-3, pouring into ethanol to collect the precipitate, and vacuum drying to obtain sulfonic acid polyaspartic acid; S2, fully mixing thionyl chloride and tetrahydrofuran, then adding sulfonic acid polyaspartic acid, stirring and treating under reflux conditions for 2-6 hours, and after the treatment, reducing the pressure to completely dryness to obtain sulfonyl chloride polyaspartic acid; S3. Add sulfonyl chloride polyaspartic acid and 5-aminolevulinic acid into tetrahydrofuran, stir well, then drop triethylamine, stir and react at room temperature for 2-8 hours. After the reaction is completed, reduce the pressure to complete dryness to obtain modified polyaspartic acid.

7. The special blended fertilizer for corn according to claim 6, characterized in that: In the 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.

8. The special blended fertilizer for corn according to claim 6, characterized in that: In the S2, the mass ratio of sulfonic acid polyaspartic acid, dithionyl chloride and tetrahydrofuran is 1:2-5:5-10.

9. The special blended fertilizer for corn according to claim 6, characterized in that: In the S3, the mass ratio of sulfonyl chloride polyaspartic acid, 5-aminolevulinic acid and tetrahydrofuran is 1:1.3-1.8:10-20.

10. A method for preparing the special blended fertilizer for corn according to claim 1, characterized in that: The following steps are involved: Step 1. Add modified polyaspartic acid and emulsifier into 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 evenly, then add solution B and stir at room temperature. After stirring, centrifuge the system at low temperature and high speed, remove the supernatant, freeze-dry the precipitate, and prepare a particle material containing the inhibitor; Step 3. Mixing the vegetable oil polyol, isocyanate and the particle material containing the inhibitor to obtain the active coating material, then preheating the urea particles, adding the active coating material, and forming a film to obtain a loaded coated fertilizer; Step 4. Take compound fertilizer particles, spray cassava starch adhesive on the surface of the compound fertilizer particles, then wrap zinc sulfate monohydrate on the surface of the fertilizer particles sprayed with starch adhesive, and obtain inorganic compound fertilizer after drying; Step 5. The loaded coated fertilizer obtained in step 3 and the inorganic compound fertilizer obtained in step 4 are blended to obtain the special blended fertilizer for corn.

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