Slow-release fertilizer for silage corn and preparation method of slow-release fertilizer

Abstract

The invention provides a silage corn slow-release fertilizer and a preparation method thereof, and belongs to the technical field of slow-release fertilizers. The method comprises the following steps: mixing zirconocene dichloride and ethynyl biphenyl-3, 3 ', 5, 5'-tetracarboxylic acid, adding N, N-dimethylacetamide and water, reacting at 50-80 DEG C for 15-20 hours, cooling to room temperature, and washing with N, N-dimethylacetamide to obtain a porous carrier; mixing the porous carrier with dipotassium phosphate, ammonium chloride and water, and dispersing to obtain dispersion liquid; adding agricultural wastes into the dispersion liquid, uniformly stirring, slowly dropwise adding ammonium persulfate, and adding a monomer and a cross-linking agent to obtain a mixed solution; reacting for 1-2 hours at 60-80 DEG C in an inert atmosphere to obtain a semi-finished product; and washing and drying the obtained semi-finished product to obtain the silage corn slow-release fertilizer. The slow-release fertilizer provided by the invention can improve the water retention capacity of soil and prolong the nutrient release time, and is suitable for sandy soil or arid and semi-arid regions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of slow-release fertilizer, in particular to a silage corn slow-release fertilizer and a preparation method thereof. BACKGROUND

[0002] Silage corn refers to corn plants including corn ears, which are all harvested, chopped and processed, and then fermented to produce silage feed, which is used to feed ruminants such as cattle and sheep in winter. Compared with ordinary corn, silage corn has the characteristics of good fiber quality, high dry matter content, rich nutrition, good green retention, and higher digestion and absorption rate than ordinary corn.

[0003] Slow-release fertilizer is a type of fertilizer that uses physical, chemical and biological methods to slowly release effective components in organic or inorganic fertilizers in the soil. Compared with ordinary instant fertilizer, slow-release fertilizer has the following characteristics: it can meet the nutrient requirements of crops at one time, prolong the fertilizer effect, improve the utilization rate of fertilizer, reduce the amount and frequency of fertilizer application, save labor, reduce the pollution of fertilizer loss to the environment, etc. At present, slow-release fertilizer is mainly divided into three categories, including (1) physical coating slow-release fertilizer, which is coated or smeared with a layer of film on the surface of the fertilizer. The coating material is divided into inorganic material and organic polymer material. The inorganic material includes bentonite, gypsum, etc., and the organic polymer material includes polyethylene, resin, starch, cellulose, etc.; (2) chemical combination type slow-release fertilizer, which connects the fertilizer and the polymer material together through chemical action to form a new compound. The release rate of effective components is mainly affected by the hydrophobicity, degradation degree and chemical structure of the compound; (3) biological inhibition type slow-release fertilizer, which adds a certain amount of urease inhibitor or nitrification inhibitor to the fertilizer to improve the utilization rate of nitrogen elements in the fertilizer. The mechanism of nitrification inhibitor is to affect the biological activity of nitrifying bacteria by releasing toxic substances to inhibit the nitrification effect of the soil. The urease inhibitor inhibits the activity of urease to reduce the hydrolysis time of urea.

[0004] However, the slow-release fertilizer has the following problems in actual use, is not suitable for use in arid soil, and nutrients in the fertilizer cannot be effectively released in the absence of water, thereby affecting the growth and development of crops and causing crop yield reduction. The patent application No. 201110279923.1 discloses a corn slow-release fertilizer, which is prepared by uniformly spraying a layer of water-soluble polymer on the surface of fertilizer particles, wherein the components of the corn slow-release fertilizer are (NH4)2HPO4: K2SO4: large particle urea: diatomite: high molecular polymer. The slow-release fertilizer prepared by the patent can improve nitrogen utilization rate and crop yield, but part of the raw materials used in the patent are from petrochemical products, which are non-renewable resources and difficult to degrade, and are easy to cause secondary pollution. The patent application No. 201110379294.X discloses a high-efficiency slow-release corn special fertilizer rich in zinc element and a preparation method thereof. The patent uses small particle urea, monoammonium phosphate, potassium chloride, urease inhibitor, zinc sulfate and other trace elements, and bentonite as raw materials to prepare a slow-release fertilizer for corn according to a specified process and proportion. Although the fertilizer can improve nitrogen utilization rate, it has defects such as unstable field effect, poor environmental adaptability, high requirement for soil properties and high cost in actual use. SUMMARY

[0005] Therefore, the application provides a preparation method of a silage corn slow-release fertilizer, which comprises the following steps:

[0006] (1) mixing dichlorobis-cyclopentadienyl zirconium and ethynyl biphenyl-3,3',5,5'-tetracarboxylic acid, adding N,N-dimethylacetamide and ultrapure water, reacting at 50-80℃ for 15-20h, washing with N,N-dimethylacetamide after being reduced to room temperature, and obtaining a porous carrier;

[0007] (2) mixing the porous carrier in step (1) with dipotassium hydrogen phosphate, ammonium chloride and water, ultrasonic dispersion, obtaining a dispersion liquid; then adding agricultural waste in the dispersion liquid, stirring uniformly, slowly adding ammonium persulfate, adding monomer and crosslinking agent while stirring, obtaining a mixed solution; reacting at 60-80℃ for 1-2h under inert atmosphere protection, obtaining a semi-finished product; repeatedly washing the obtained semi-finished product with anhydrous ethanol, drying, and obtaining a silage corn slow-release fertilizer.

[0008] Further, the mass-volume ratio of dichlorobis-cyclopentadienyl zirconium, ethynyl biphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water in step (1) is 5-9: 1-2: 70-90: 38-50.

[0009] Further, the mass ratio of the porous carrier, dipotassium hydrogen phosphate and ammonium chloride in step (2) is 1-3: 0.5-0.8: 1-2.

[0010] Furthermore, in step (2), the ultrasonic dispersion power is 200-500W and the time is 5-15min.

[0011] Furthermore, the agricultural waste mentioned in step (2) includes at least one of sugarcane bagasse, corn stalks, and wheat stalks.

[0012] Furthermore, the mass ratio of agricultural waste to porous carrier in step (2) is 1:3-5.

[0013] Furthermore, the amount of ammonium persulfate added in step (2) is 0.5% to 2.0% of the total mass of the monomer.

[0014] Furthermore, the monomer in step (2) is composed of fumaric acid and malic acid in a mass ratio of 1:2-5, and the monomer accounts for 40%-60% of the total solid content of the system.

[0015] Furthermore, the amount of crosslinking agent added in step (2) is 0.1% to 0.5% of the total mass of the monomer.

[0016] Furthermore, the drying temperature in step (2) is 55~75℃, and the time is 8-24h.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The porous carrier synthesized in this invention has the advantages of large specific surface area and high porosity, which can adsorb and store water and nutrients. At the same time, the formation of a three-dimensional polymer network structure and the presence of a large number of hydrophilic groups further enhance the water retention capacity and slow release performance of the slow-release fertilizer, prolong the nutrient release time, and are suitable for use in sandy soils or arid and semi-arid regions.

[0019] The slow-release fertilizer preparation method provided by this invention is simple, environmentally friendly, low-cost, and improves the utilization rate of agricultural waste. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] Unless otherwise specified, the test methods or experimental methods described in the following examples are all conventional methods; unless otherwise specified, the raw materials and additives are obtained from conventional commercial sources or prepared by conventional methods.

[0022] In the following examples or comparative examples, the particle size of agricultural waste is 3 ± 0.2 mm.

[0023] Example 1

[0024] A method for preparing slow-release silage fertilizer for corn, comprising the following steps:

[0025] (1) After mixing zirconium dichlorocerocene and ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water were added. The mass-volume ratio of zirconium dichlorocerocerocene, ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water was 7:1:82:41. The mixture was reacted at 70°C for 18 h. After cooling to room temperature, the mixture was washed three times with N,N-dimethylacetamide to obtain a porous support.

[0026] (2) The porous carrier described in step (1) is mixed with dipotassium hydrogen phosphate, ammonium chloride and water. The mass ratio of the porous carrier to dipotassium hydrogen phosphate and ammonium chloride is 2:0.6:1. The amount of water added is 26 times the mass of the porous carrier. The mixture is ultrasonically dispersed for 10 minutes under 300W conditions to obtain a dispersion.

[0027] (3) Next, add agricultural waste sugarcane bagasse to the dispersion. The mass ratio of the agricultural waste to the porous carrier is 1:3.5. Stir evenly, then slowly add ammonium persulfate. While stirring, add fumaric acid, malic acid and crosslinking agent. The mass ratio of fumaric acid to malic acid is 1:3. The amount of crosslinking agent added is 0.2% of the total mass of the monomers, and the amount of ammonium persulfate added is 1.5% of the total mass of the monomers to obtain a mixed solution. Under the protection of an inert atmosphere, react at 70°C for 1 hour to obtain a semi-finished product. Wash the obtained semi-finished product repeatedly with anhydrous ethanol and dry at 58°C for 15 hours to obtain silage corn slow-release fertilizer.

[0028] Comparative Example 1

[0029] The difference from Example 1 is that an equal amount of 2,6-naphthodicarboxylic acid is used to replace ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid in step (1).

[0030] Comparative Example 2

[0031] The difference from Example 1 is that the mass-to-volume ratio of zirconium dichlorocerocene, ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide, and ultrapure water is 7:3:82:41.

[0032] Comparative Example 3

[0033] The difference from Example 1 is that the mass-to-volume ratio of zirconium dichlorocerocene, ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water is 7:0.5:82:41.

[0034] Comparative Example 4

[0035] The difference from Example 1 is that no agricultural waste is added in step (3).

[0036] Comparative Example 5

[0037] The difference from Example 1 is that fumaric acid is not added in step (3).

[0038] Comparative Example 6

[0039] The difference from Example 1 is that malic acid is not added in step (3).

[0040] Comparative Example 7

[0041] The difference from Example 1 is that the mass ratio of fumaric acid to malic acid is 1:6.

[0042] Comparative Example 8

[0043] The difference from Example 1 is that the mass ratio of fumaric acid to malic acid is 1:1.

[0044] Comparative Example 9

[0045] The difference from Example 1 is that an equal amount of acrylic acid is used to replace fumaric acid and malic acid.

[0046] Effect verification:

[0047] 1) Sustained-release

[0048] 5g of slow-release fertilizer sample and 200g of sandy soil (pH 7.2) were mixed thoroughly to obtain a mixture. The mixture was placed in a glass column, and distilled water was added to the column until saturation. 30ml of soil leachate was collected on days 0, 3, 6, 15, and 30, with an equal volume of distilled water added to the column to maintain a constant volume. The concentration of ammonium ions was determined at 697nm using the salicylic acid method. The results are shown in Table 1.

[0049] Table 1

[0050] (ii) Water retention

[0051] 1g of slow-release fertilizer sample was mixed thoroughly with 80g of sandy soil (pH 7.2) to obtain a mixture. Water was added until the sample was saturated. The ambient temperature was maintained at 25±0.5℃. The total weight was recorded on days 0, 3, 6, 9, and 12. The results are shown in Table 2. The formula for calculating the water retention rate of the sample is:

[0052]

[0053] Where WR represents the water retention rate, m1 represents the total weight (g) after adding water, and m i This represents the total weight (g) recorded each day.

[0054] Table 2

[0055] Example 2

[0056] A method for preparing slow-release silage fertilizer for corn, comprising the following steps:

[0057] (1) After mixing zirconium dichlorocerocero and ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water were added. The mass-volume ratio of zirconium dichlorocerocero, ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water was 5:1:70:38. The mixture was reacted at 50°C for 15 h. After cooling to room temperature, the mixture was washed three times with N,N-dimethylacetamide to obtain a porous support.

[0058] (2) The porous carrier described in step (1) is mixed with dipotassium hydrogen phosphate, ammonium chloride and water. The mass ratio of the porous carrier to dipotassium hydrogen phosphate and ammonium chloride is 1:0.5:1. The amount of water added is 25 times the mass of the porous carrier. The mixture is ultrasonically dispersed for 5 minutes under 200W conditions to obtain a dispersion.

[0059] (3) Next, add agricultural waste corn stalks to the dispersion, the mass ratio of agricultural waste to porous carrier is 1:3, stir evenly, and then slowly add ammonium persulfate, the amount of ammonium persulfate added is 0.5% of the total mass of monomers. While stirring, add fumaric acid, malic acid and crosslinking agent, the mass ratio of fumaric acid to malic acid is 1:2, and the amount of crosslinking agent added is 0.1% of the total mass of monomers to obtain a mixed solution; under the protection of an inert atmosphere, react at 70°C for 1 h to obtain a semi-finished product; wash the obtained semi-finished product repeatedly with anhydrous ethanol, dry at 55°C for 8 h to obtain silage corn slow-release fertilizer.

[0060] Example 3

[0061] A method for preparing slow-release silage fertilizer for corn, comprising the following steps:

[0062] (1) After mixing zirconium dichlorocerocero and ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water were added. The mass-volume ratio of zirconium dichlorocerocero, ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water was 6:1:73:40. The mixture was reacted at 57°C for 16 h. After cooling to room temperature, the mixture was washed three times with N,N-dimethylacetamide to obtain a porous support.

[0063] (2) The porous carrier described in step (1) is mixed with dipotassium hydrogen phosphate, ammonium chloride and water. The mass ratio of the porous carrier to dipotassium hydrogen phosphate and ammonium chloride is 2.5:0.5:1. The amount of water added is 27 times the mass of the porous carrier. The mixture is ultrasonically dispersed for 7 minutes under 280W conditions to obtain a dispersion.

[0064] (3) Next, add agricultural waste sugarcane bagasse to the dispersion. The mass ratio of the agricultural waste to the porous carrier is 1:4. Stir evenly and then slowly add ammonium persulfate. The amount of ammonium persulfate added is 1.3% of the total mass of the monomers. While stirring, add the monomers fumaric acid, malic acid and crosslinking agent. The mass ratio of fumaric acid to malic acid is 1:3. The amount of crosslinking agent added is 0.4% of the total mass of the monomers to obtain a mixed solution. Under the protection of an inert atmosphere, react at 65°C for 1 hour to obtain a semi-finished product. Wash the obtained semi-finished product repeatedly with anhydrous ethanol and dry at 58°C for 13 hours to obtain silage corn slow-release fertilizer.

[0065] Example 4

[0066] A method for preparing slow-release silage fertilizer for corn, comprising the following steps:

[0067] (1) After mixing zirconium dichlorocerocene and ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water were added. The mass-volume ratio of zirconium dichlorocerocerocene, ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water was 8:2:88:47. The mixture was reacted at 75°C for 20 h. After cooling to room temperature, the mixture was washed three times with N,N-dimethylacetamide to obtain a porous support.

[0068] (2) The porous carrier described in step (1) is mixed with dipotassium hydrogen phosphate, ammonium chloride and water. The mass ratio of the porous carrier to dipotassium hydrogen phosphate and ammonium chloride is 3:0.7:2. The amount of water added is 30 times the mass of the porous carrier. The mixture is ultrasonically dispersed for 15 minutes under 400W conditions to obtain a dispersion.

[0069] (3) Next, add agricultural waste sugarcane bagasse to the dispersion. The mass ratio of the agricultural waste to the porous carrier is 1:5. Stir evenly and then slowly add ammonium persulfate. The amount of ammonium persulfate added is 2.0% of the total mass of the monomer. While stirring, add fumaric acid, malic acid and crosslinking agent. The mass ratio of fumaric acid to malic acid is 1:4. The amount of crosslinking agent added is 0.5% of the total mass of the monomer to obtain a mixed solution. Under the protection of an inert atmosphere, react at 80°C for 2 hours to obtain a semi-finished product. Wash the obtained semi-finished product repeatedly with anhydrous ethanol and dry at 70°C for 22 hours to obtain silage corn slow-release fertilizer.

[0070] Example 5

[0071] A method for preparing slow-release silage fertilizer for corn, comprising the following steps:

[0072] (1) After mixing zirconium dichlorocerocene and ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water were added. The mass-volume ratio of zirconium dichlorocerocerocene, ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water was 9:2:90:50. The mixture was reacted at 80°C for 20 h. After cooling to room temperature, the mixture was washed three times with N,N-dimethylacetamide to obtain a porous support.

[0073] (2) The porous carrier described in step (1) is mixed with dipotassium hydrogen phosphate, ammonium chloride and water. The mass ratio of the porous carrier to dipotassium hydrogen phosphate and ammonium chloride is 3:0.8:2. The amount of water added is 30 times the mass of the porous carrier. The mixture is ultrasonically dispersed for 15 minutes under 500W conditions to obtain a dispersion.

[0074] (3) Next, add agricultural waste wheat straw to the dispersion, the mass ratio of agricultural waste to porous carrier is 1:5, stir evenly, and then slowly add ammonium persulfate, the amount of ammonium persulfate added is 2.0% of the total mass of monomers. While stirring, add fumaric acid, malic acid and crosslinking agent, the mass ratio of fumaric acid and malic acid is 1:5, and the amount of crosslinking agent added is 0.5% of the total mass of monomers to obtain a mixed solution; under the protection of an inert atmosphere, react at 80°C for 2 hours to obtain a semi-finished product; wash the obtained semi-finished product repeatedly with anhydrous ethanol, dry at 75°C for 24 hours to obtain silage corn slow-release fertilizer.

[0075] Experiments have shown that the slow-release silage fertilizers provided in Examples 2-5 can also improve soil water retention capacity and prolong nutrient release time. The experimental results of Examples 2-5 are not significantly different from those of Example 1.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing slow-release silage fertilizer for corn, characterized in that, Includes the following steps: (1) After mixing zirconium dichlorocerocene and ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water were added, and the mixture was reacted at 50-80℃ for 15-20h. After cooling to room temperature, the mixture was washed with N,N-dimethylacetamide to obtain a porous support. (2) The porous carrier described in step (1) is mixed with dipotassium hydrogen phosphate, ammonium chloride and water, and ultrasonically dispersed to obtain a dispersion; then agricultural waste is added to the dispersion and stirred evenly, and then ammonium persulfate is slowly added dropwise while stirring to add monomer and crosslinking agent to obtain a mixed solution; under inert atmosphere protection, the reaction is carried out at 60-80℃ for 1-2 hours to obtain a semi-finished product; the obtained semi-finished product is repeatedly washed with anhydrous ethanol and dried to obtain silage corn slow-release fertilizer.

2. The method for preparing slow-release silage fertilizer for corn according to claim 1, characterized in that, The mass-to-volume ratio of zirconium dichlorocerocene, ethynylbiphenyl-3,3',5,5'-tetracarboxylic acid, N,N-dimethylacetamide and ultrapure water in step (1) is 5-9:1-2:70-90:38-50.

3. The method for preparing slow-release silage fertilizer for corn according to claim 1, characterized in that, The mass ratio of the porous carrier to dipotassium hydrogen phosphate and ammonium chloride in step (2) is 1-3:0.5-0.8:1-2.

4. The method for preparing slow-release silage fertilizer for corn according to claim 1, characterized in that, In step (2), the ultrasonic dispersion power is 200-500W and the time is 5-15min.

5. The method for preparing slow-release silage fertilizer for corn according to claim 1, characterized in that, The agricultural waste mentioned in step (2) includes at least one of sugarcane bagasse, corn stalks, and wheat stalks.

6. The method for preparing slow-release silage fertilizer for corn according to claim 1, characterized in that, The mass ratio of agricultural waste to porous carrier in step (2) is 1:3-5.

7. The method for preparing slow-release silage fertilizer for corn according to claim 1, characterized in that, The amount of ammonium persulfate added in step (2) is 0.5% to 2.0% of the total mass of the monomer.

8. The method for preparing slow-release silage fertilizer for corn according to claim 1, characterized in that, The monomer in step (2) is composed of fumaric acid and malic acid in a mass ratio of 1:2-5, and the monomer accounts for 40%-60% of the total solid content of the system.

9. The method for preparing slow-release silage fertilizer for corn according to claim 1, characterized in that, The amount of crosslinking agent added in step (2) is 0.1% to 0.5% of the total mass of the monomer.

10. The method for preparing slow-release silage fertilizer for corn according to claim 1, characterized in that, The drying temperature in step (2) is 55~75℃, and the time is 8-24h.

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