CN116283422A - Improved double-layer coated controlled release urea of nitrogenous fertilizer synergist and preparation method thereof - Google Patents
Improved double-layer coated controlled release urea of nitrogenous fertilizer synergist and preparation method thereof Download PDFInfo
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- CN116283422A CN116283422A CN202310236516.5A CN202310236516A CN116283422A CN 116283422 A CN116283422 A CN 116283422A CN 202310236516 A CN202310236516 A CN 202310236516A CN 116283422 A CN116283422 A CN 116283422A
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- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 133
- 239000004202 carbamide Substances 0.000 title claims abstract description 133
- 238000013270 controlled release Methods 0.000 title claims abstract description 68
- 239000000618 nitrogen fertilizer Substances 0.000 title claims abstract description 57
- 238000002360 preparation method Methods 0.000 title claims abstract description 15
- 239000011248 coating agent Substances 0.000 claims abstract description 66
- 239000003337 fertilizer Substances 0.000 claims abstract description 58
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 55
- 238000000576 coating method Methods 0.000 claims abstract description 54
- 239000002245 particle Substances 0.000 claims abstract description 34
- 239000005543 nano-size silicon particle Substances 0.000 claims abstract description 27
- 239000003112 inhibitor Substances 0.000 claims abstract description 24
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 23
- PMYDPQQPEAYXKD-UHFFFAOYSA-N 3-hydroxy-n-naphthalen-2-ylnaphthalene-2-carboxamide Chemical compound C1=CC=CC2=CC(NC(=O)C3=CC4=CC=CC=C4C=C3O)=CC=C21 PMYDPQQPEAYXKD-UHFFFAOYSA-N 0.000 claims abstract description 20
- 229960001881 sodium selenate Drugs 0.000 claims abstract description 20
- 235000018716 sodium selenate Nutrition 0.000 claims abstract description 20
- 239000011655 sodium selenate Substances 0.000 claims abstract description 20
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 claims abstract description 13
- 235000010413 sodium alginate Nutrition 0.000 claims abstract description 13
- 229940005550 sodium alginate Drugs 0.000 claims abstract description 13
- 239000000661 sodium alginate Substances 0.000 claims abstract description 13
- 229940090496 Urease inhibitor Drugs 0.000 claims abstract description 12
- 239000002601 urease inhibitor Substances 0.000 claims abstract description 12
- 238000002156 mixing Methods 0.000 claims abstract description 4
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- 238000000034 method Methods 0.000 claims description 23
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical group NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 claims description 19
- HEPPIYNOUFWEPP-UHFFFAOYSA-N n-diaminophosphinothioylbutan-1-amine Chemical group CCCCNP(N)(N)=S HEPPIYNOUFWEPP-UHFFFAOYSA-N 0.000 claims description 19
- 238000001816 cooling Methods 0.000 claims description 18
- 239000012948 isocyanate Substances 0.000 claims description 13
- 150000002513 isocyanates Chemical class 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 13
- 229920005906 polyester polyol Polymers 0.000 claims description 13
- 239000008367 deionised water Substances 0.000 claims description 10
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- 238000003756 stirring Methods 0.000 claims description 10
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- 230000008018 melting Effects 0.000 claims description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 74
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 37
- 239000010410 layer Substances 0.000 abstract description 36
- 239000002689 soil Substances 0.000 abstract description 22
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 abstract description 13
- 229910052711 selenium Inorganic materials 0.000 abstract description 12
- 239000011669 selenium Substances 0.000 abstract description 12
- 229940091258 selenium supplement Drugs 0.000 abstract description 12
- 238000006243 chemical reaction Methods 0.000 abstract description 5
- 239000011573 trace mineral Substances 0.000 abstract description 5
- 235000013619 trace mineral Nutrition 0.000 abstract description 5
- 230000003111 delayed effect Effects 0.000 abstract description 3
- 229920006254 polymer film Polymers 0.000 abstract description 3
- 239000000377 silicon dioxide Substances 0.000 abstract description 3
- 239000012528 membrane Substances 0.000 abstract description 2
- 239000002105 nanoparticle Substances 0.000 abstract description 2
- 239000002355 dual-layer Substances 0.000 abstract 1
- 238000011282 treatment Methods 0.000 description 42
- 240000008042 Zea mays Species 0.000 description 19
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 19
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 19
- 235000005822 corn Nutrition 0.000 description 19
- 230000000694 effects Effects 0.000 description 17
- 238000012360 testing method Methods 0.000 description 14
- 230000008901 benefit Effects 0.000 description 10
- 230000001965 increasing effect Effects 0.000 description 8
- MMDJDBSEMBIJBB-UHFFFAOYSA-N [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] Chemical compound [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] MMDJDBSEMBIJBB-UHFFFAOYSA-N 0.000 description 6
- 239000000047 product Substances 0.000 description 6
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- 230000008569 process Effects 0.000 description 4
- 229910002651 NO3 Inorganic materials 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
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- 239000012188 paraffin wax Substances 0.000 description 3
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- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 2
- 108010046334 Urease Proteins 0.000 description 2
- RDXARWSSOJYNLI-UHFFFAOYSA-N [P].[K] Chemical compound [P].[K] RDXARWSSOJYNLI-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
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- 229920000642 polymer Polymers 0.000 description 2
- 229920003222 semicrystalline poly(phosphazene) Polymers 0.000 description 2
- 230000017260 vegetative to reproductive phase transition of meristem Effects 0.000 description 2
- ZZZCUOFIHGPKAK-UHFFFAOYSA-N D-erythro-ascorbic acid Natural products OCC1OC(=O)C(O)=C1O ZZZCUOFIHGPKAK-UHFFFAOYSA-N 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- PDNNQADNLPRFPG-UHFFFAOYSA-N N.[O] Chemical compound N.[O] PDNNQADNLPRFPG-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 101100115213 Schizosaccharomyces pombe (strain 972 / ATCC 24843) cul1 gene Proteins 0.000 description 1
- 101100168904 Schizosaccharomyces pombe (strain 972 / ATCC 24843) cul3 gene Proteins 0.000 description 1
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- 229930002877 anthocyanin Natural products 0.000 description 1
- 235000010208 anthocyanin Nutrition 0.000 description 1
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- 150000004636 anthocyanins Chemical class 0.000 description 1
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- 210000005069 ears Anatomy 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000004720 fertilization Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000003306 harvesting Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
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- 239000011591 potassium Substances 0.000 description 1
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C9/00—Fertilisers containing urea or urea compounds
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
- C05G3/40—Mixtures of one or more fertilisers with additives not having a specially fertilising activity for affecting fertiliser dosage or release rate; for affecting solubility
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
- C05G3/90—Mixtures of one or more fertilisers with additives not having a specially fertilising activity for affecting the nitrification of ammonium compounds or urea in the soil
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G5/00—Fertilisers characterised by their form
- C05G5/10—Solid or semi-solid fertilisers, e.g. powders
- C05G5/12—Granules or flakes
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G5/00—Fertilisers characterised by their form
- C05G5/30—Layered or coated, e.g. dust-preventing coatings
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P60/00—Technologies relating to agriculture, livestock or agroalimentary industries
- Y02P60/20—Reduction of greenhouse gas [GHG] emissions in agriculture, e.g. CO2
- Y02P60/21—Dinitrogen oxide [N2O], e.g. using aquaponics, hydroponics or efficiency measures
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Pest Control & Pesticides (AREA)
- Soil Sciences (AREA)
- Fertilizers (AREA)
Abstract
The invention discloses a dual-layer coated controlled release urea modified by a nitrogenous fertilizer synergist and a preparation method thereof, belonging to the technical field of coated controlled release fertilizers. The preparation method of the controlled release urea comprises the following steps: preheating large-particle urea; (2) Coating a nitrification inhibitor and a urease inhibitor on the surface of the large-particle urea by adopting a coating machine; (3) Coating the surface of the large-particle urea with a polymer film by adopting a coating machine to form an inner coating; (4) preparing mesoporous nano silicon dioxide loaded with sodium selenate; (5) Mixing mesoporous nano silicon dioxide loaded with sodium selenate with sodium alginate solution, and forming an outer gel membrane shell on the surface of fertilizer particles. According to the invention, the nitrogen fertilizer synergist is combined with the double-layer coating so as to jointly regulate and control the release of nitrogen and the conversion and utilization of nitrogen in soil, and the mesoporous silica nanoparticles loaded with sodium selenate are utilized to further modify the outer gel, so that the double-layer coating controlled release urea is prepared, and the release of trace element selenium is delayed.
Description
Technical Field
The invention belongs to the technical field of coated controlled release fertilizers, and particularly relates to an improved double-layer coated controlled release urea of a nitrogenous fertilizer synergist and a preparation method thereof.
Background
Because of the long-term unreasonable application of the nitrogenous fertilizer, the utilization rate of the nitrogenous fertilizer in China in the season is only 30% -35%, which is far lower than that of the overseas developed countries. In the summer corn growing period, the positive value is high in the rainy season, the precipitation amount is large and concentrated, nitrogen leaching is easy to occur, and the environmental problems of agricultural non-point source pollution, greenhouse gas and the like are caused. The coated controlled release fertilizer is used as one of novel fertilizers, the nutrient release curve of the fertilizer accords with the fertilizer requirement rule of crops, the defect that urea is dissolved too fast in soil can be overcome, the conversion process of urea after the urea enters the soil cannot be controlled, and meanwhile, the controlled release fertilizer is easily influenced by environmental factors such as temperature, moisture and the like, so that the release effect of the controlled release fertilizer is influenced to a certain extent; the stable fertilizer can inhibit urease activity, ammonia-oxygen microorganism colony to slow down hydrolysis of urea and inhibit nitrification and denitrification processes in soil by adding nitrogen fertilizer synergist. The nitrogen fertilizer synergist mainly comprises a urease inhibitor and a nitrification inhibitor. There are many compounds developed today that have urease inhibiting effect, but there are few truly commercialized classes, and the most widely used urease inhibitor in the market at present is NBPT; the nitrification inhibitor has more than 150, but the DCD has wide application in agriculture due to the advantages of low cost, low volatility, good water solubility and the like. After the nitrogen fertilizer synergist is physically combined with the fertilizer, the fertilizer is granulated by high tower spraying, and raw materials used in the production process are high in water solubility and easy to degrade and transfer due to field factors, so that the product is degraded, and the field action duration and energy efficiency of the fertilizer are reduced.
The preparation of the existing coated controlled release fertilizer and the existing stable fertilizer products is mature, but the products which combine the advantages of the coated controlled release fertilizer and the stable fertilizer and achieve better controlled release effect are few in the market. Chinese patent 200610134753.7 discloses a resin coated controlled release fertilizer and a preparation method thereof, wherein the coating is carried out on the basis of preparing a coated inhibitor urea fertilizer core by firstly coating a biochemical inhibitor, and the process is carried out in two steps, so that the coating is tight and compact, and the biochemical inhibitor and urea release effect is controlled to a certain extent. However, the polymer single-layer coating adopted in the patent has poor controlled release effect, low nutrient utilization rate and single function, and can not provide nitrogen for crops and improve trace elements. Chinese patent 200710141887.6 discloses a water-based polymer-paraffin double-layer coated controlled release fertilizer and a preparation method thereof, wherein paraffin is coated on the surface of fertilizer particles, and then a composite coating agent containing water-based polymer emulsion and biodegradable natural polymers is coated on the surface of the fertilizer coated with paraffin to form a polymer film. Although the patent adopts a double-layer film, the combination of a nitrogen fertilizer synergist and a coating film to jointly regulate and control the release of nitrogen and the conversion and utilization of nitrogen in soil is not disclosed, and the function is single, so that trace elements can not be improved while the nitrogen is provided for crops.
Disclosure of Invention
The invention aims to provide an improved double-layer coated controlled release urea of a nitrogenous fertilizer synergist and a preparation method thereof, wherein the urea and trace elements can be released under the premise of controlling lower cost, and absorption and conversion of urea in soil can be relieved.
The invention is realized by adopting the following technical scheme:
the preparation method of the improved double-layer coated controlled release urea of the nitrogenous fertilizer synergist comprises the following steps:
(1) Starting a coating machine, and preheating large-particle urea in a rotary drum;
(2) Preparing a nitrification inhibitor into a solution according to 0.03-0.06% of the mass of urea, spraying the nitrification inhibitor solution on the surface of the urea in a coating machine, uniformly coating, keeping the temperature of the urea at 60-65 ℃ after the water is completely evaporated, adding urease inhibitor powder according to the addition amount of 0.03-0.06% of the mass of urea, completely melting the urease inhibitor, uniformly coating on the surface of the urea, and cooling to 50-55 ℃;
(3) Weighing a proper amount of polyester polyol and isocyanate which are heated to be in a liquid state, adding the polyester polyol and the isocyanate into a container, mixing to prepare a coating agent, uniformly dripping the coating agent with the mass of 0.3% -0.6% of urea on the surface of large-particle urea moving in a coating machine, reacting for 5-10min, and curing to form a film; repeating the above operation for 2-5 times, cooling the material in motion for 15-25min, and cooling the coated large-particle urea to 30-35 ℃ to form an inner coating;
(4) Firstly dispersing nano silicon dioxide in deionized water to uniformly disperse the nano silicon dioxide, adding sodium selenate into the nano silicon dioxide dispersion system, wherein the mass ratio of the nano silicon dioxide to the sodium selenate is 1:1.5-2.5, magnetically stirring for 20-30h, centrifugally collecting mesoporous nano silicon dioxide precipitate loaded with sodium selenate, and drying and marking as MSN@Se;
(5) Dispersing 0.01% -0.02% of MSN@Se by mass of urea in distilled water, dissolving 0.03% -0.06% of sodium alginate by mass of urea in deionized water, stirring by magnetic force until the sodium alginate is completely dissolved, pouring MSN@Se suspension into sodium alginate solution, oscillating the mixture by an oscillating machine to form uniform suspension MSN@Se@SA, slowly dripping MSN@Se@SA into the surfaces of rotating fertilizer particles, forming an outer gel film shell under the condition of continuous rotation, and repeating the operation for 2-5 times to obtain the double-layer coated controlled release urea.
As a preferable scheme, the operation parameters of the coating machine in the step (1) are that the rotating speed is set to be 50rpm, the hot air temperature is set to be 85-95 ℃, and when the large-particle urea is preheated to 58-62 ℃, the hot air temperature is adjusted to be 65-70 ℃.
As a preferable mode, the method for preparing the nitrification inhibitor of the solution in the step (2) comprises: the nitrification inhibitor is prepared by the following components in percentage by mass: 10 is added into 80 ℃ hot water to prepare a solution.
Preferably, the nitrification inhibitor is dicyandiamide, and the urease inhibitor is N-butyl thiophosphoric triamide.
As a preferable scheme, the coating mass accounts for 1.5% -3.5% of the urea mass.
Preferably, the mass ratio of the polyester polyol to the isocyanate is 5:3.
The invention also provides the improved double-layer coated controlled release urea of the nitrogenous fertilizer synergist prepared by the method.
Compared with the prior art, the invention has the beneficial effects that:
(1) The improved double-layer coated controlled release urea of the nitrogen fertilizer synergist prepared by the method effectively controls and delays the release time, the hydrolysis time and the conversion time of urea in soil, so that the coated effect is complementary with the effect of a biochemical inhibitor, the synergistic effect of the urea is fully exerted, the effect principle of a urease inhibitor NBPT and a nitrification inhibitor DCD is complementary, the fertilizer efficiency period of the urea is obviously prolonged, the requirement of one-time basal application of nitrogen fertilizer for the nitrogen fertilizer in the whole growing season of crops is met, and the labor and time are saved in agricultural production;
(2) The method takes urea as a core, takes a coating agent formed by mixing polyester polyol and isocyanate as an inner coating material, and further modifies outer gel by mesoporous silica nano particles loaded with sodium selenate to prepare the double-layer multifunctional coated controlled release fertilizer, which can provide nitrogen for crops and improve trace element selenium at the same time, so that the crops are rich in selenium and beneficial to human health, and the coated controlled release fertilizer is 1.4 times of a single coated fertilizer, and compared with a quick-acting selenium fertilizer, the selenium release period is improved by 40 times; the action mechanism is as follows: when moisture enters the outer gel film layer, the moisture is combined with gel through hydrogen bonds and stored in a gel network, so that the rate of entering the inner film shell by the moisture is slowed down, and the release of nutrients is delayed; on the other hand, mesoporous structure and positively charged groups on the surface of the silicon dioxide can adsorb selenate with negative charges, and the network structure of the gel membrane shell increases the diffusion path of selenium, so that the release of selenium is delayed;
(3) Compared with common coated urea, the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist prepared by the method can improve the yield and economic benefits of crops by applying the nitrogen fertilizer synergist, and the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist improves the regulation and control of urea in soil, can still keep a better yield increasing effect when reducing 20% of nitrogen, and can reduce the input cost of fertilizer, lighten the environmental pressure and ensure the yield benefits.
Detailed Description
The present invention will be further described with reference to examples and test examples. The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials, unless otherwise specified, are commercially available.
Example 1: the preparation method of the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist in the controlled release period of 30 days comprises the following steps:
(1) Starting a coating machine, setting the operation parameters of the coating machine to be 50rpm, setting the temperature of hot air to be 90 ℃, and adjusting the temperature of the hot air to 65 ℃ when the large-particle urea is preheated to 60 ℃ in a rotary drum, and keeping the hot air supply;
(2) Dicyandiamide (DCD) in a mass ratio of 1:10, adding the mixture into 80-DEG C hot water to prepare a solution, keeping a rotary drum to rotate, spraying dicyandiamide (DCD) solution on the surface of urea in a coating machine, uniformly coating, and keeping the temperature of the urea at 60 ℃ after the water is completely evaporated; adding N-butyl thiophosphoric triamide (NBPT) powder according to the adding amount of 0.03 percent of the mass of the urea, completely melting the N-butyl thiophosphoric triamide (NBPT) and uniformly coating the mixture on the surface of the urea, and cooling the mixture to 52 ℃;
(3) Weighing a proper amount of liquid polyester polyol and isocyanate which are respectively heated to 70 ℃ and 50 ℃ and added into a container to be mixed to prepare a coating agent, wherein the mass ratio of the polyester polyol to the isocyanate is 5:3, uniformly dripping the coating agent with the mass of 0.5% of the mass of urea on the surface of the large-particle urea moving in a coating machine, uniformly coating the large-particle urea by collision between the large-particle urea continuously moving, and curing to form a film after reacting for 5 min; repeating the steps for 2 times, reducing the rotating speed of the coating machine, closing a hot air heating switch, keeping a fan on, naturally cooling hot air, cooling the material in motion for 15min, and cooling coated large-particle urea to 30-35 ℃;
(4) Firstly dispersing nano silicon dioxide in deionized water to uniformly disperse the nano silicon dioxide, adding sodium selenate into the nano silicon dioxide dispersion system, wherein the mass ratio of the nano silicon dioxide to the sodium selenate is 1:2, magnetically stirring for 24 hours, centrifugally collecting mesoporous nano silicon dioxide precipitate loaded with sodium selenate, and drying and marking as MSN@Se;
(5) Dispersing 0.01% of urea mass of MSN@Se in distilled water, dissolving 0.03% of urea mass of sodium alginate in deionized water, stirring by magnetic force until the MSN@Se is completely dissolved, pouring the MSN@Se suspension into a sodium alginate solution, oscillating the mixture by an oscillating machine to form uniform suspension MSN@Se@SA, slowly dripping the MSN@Se@SA into the surfaces of rotating fertilizer particles, forming an outer gel film shell under the condition of continuous rotation, and repeating the operation for 2 times to obtain the double-layer coated controlled release urea.
The coated controlled release urea with the total coated mass accounting for 1.6 percent of the urea mass is prepared by the method, and the coated controlled release urea is a product with the controlled release period of 30 days.
Example 2: the preparation method of the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist in the controlled release period of 60 days comprises the following steps:
(1) Starting a coating machine, setting the operation parameters of the coating machine to be 50rpm, setting the temperature of hot air to be 90 ℃, preheating large-particle urea to 60 ℃ in a rotary drum, adjusting the temperature of the hot air to 65 ℃, and keeping the temperature of the hot air to be supplied;
(2) Dicyandiamide (DCD) in a mass ratio of 1:10, adding the mixture into 80-DEG C hot water to prepare a solution, keeping a rotary drum to rotate, spraying dicyandiamide (DCD) solution on the surface of urea in a coating machine, uniformly coating, and keeping the temperature of the urea at 60 ℃ after the water is completely evaporated; adding N-butyl thiophosphoric triamide (NBPT) powder according to the adding amount of 0.05 percent of the mass of urea, completely melting the N-butyl thiophosphoric triamide (NBPT) and uniformly coating the mixture on the surface of the urea, and cooling the mixture to 52 ℃;
(3) Weighing a proper amount of liquid polyester polyol and isocyanate which are respectively heated to 70 ℃ and 50 ℃ and added into a container to be mixed to prepare a coating agent, wherein the mass ratio of the polyester polyol to the isocyanate is 5:3, uniformly dripping the coating agent with the mass of 0.5% of the mass of urea on the surface of the large-particle urea moving in a coating machine, uniformly coating the large-particle urea by collision between the large-particle urea continuously moving, and curing to form a film after reacting for 8 min; repeating the steps for 3 times, reducing the rotating speed of the coating machine, closing a hot air heating switch, keeping a fan on, naturally cooling hot air, cooling the material in motion for 20min, and cooling coated large-particle urea to 30-35 ℃;
(4) Firstly dispersing nano silicon dioxide in deionized water to uniformly disperse the nano silicon dioxide, adding sodium selenate into the nano silicon dioxide dispersion system, wherein the mass ratio of the nano silicon dioxide to the sodium selenate is 1:2, magnetically stirring for 24 hours, centrifugally collecting mesoporous nano silicon dioxide precipitate loaded with sodium selenate, and drying and marking as MSN@Se;
(5) Dispersing 0.01% of urea mass of MSN@Se in distilled water, dissolving 0.04% of urea mass of sodium alginate in deionized water, stirring by magnetic force until the MSN@Se is completely dissolved, pouring MSN@Se suspension into sodium alginate solution, oscillating the mixture by an oscillating machine to form uniform suspension MSN@Se@SA, slowly dripping MSN@Se@SA into the surfaces of rotating fertilizer particles, forming an outer gel film shell under the condition of continuous rotation, and repeating the operation for 3 times to obtain the double-layer coated controlled release urea.
The coated controlled release urea with the total coated mass accounting for 2.2 percent of the urea mass is prepared by the method, and the coated controlled release urea is a product with the controlled release period of 60 days.
Example 3: the preparation method of the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist in the controlled release period of 90 days comprises the following steps:
(1) Starting a coating machine, setting the operation parameters of the coating machine to be 50rpm, setting the temperature of hot air to be 90 ℃, preheating large-particle urea to 60 ℃ in a rotary drum, adjusting the temperature of the hot air to 65 ℃, and keeping the temperature of the hot air to be supplied;
(2) Dicyandiamide (DCD) in a mass ratio of 1:10, adding the mixture into 80-DEG C hot water to prepare a solution, keeping a rotary drum to rotate, spraying dicyandiamide (DCD) solution on the surface of urea in a coating machine, uniformly coating, and keeping the temperature of the urea at 60 ℃ after the water is completely evaporated; adding N-butyl thiophosphoric triamide (NBPT) powder according to the adding amount of 0.06 percent of the mass of urea, and cooling to 52 ℃ after the N-butyl thiophosphoric triamide (NBPT) is completely melted and uniformly coated on the surface of the urea;
(3) Weighing a proper amount of liquid polyester polyol and isocyanate which are respectively heated to 70 ℃ and 50 ℃ and added into a container to be mixed to prepare a coating agent, wherein the mass ratio of the polyester polyol to the isocyanate is 5:3, uniformly dripping the coating agent with the mass of 0.5% of the mass of urea on the surface of the large-particle urea moving in a coating machine, uniformly coating the large-particle urea by collision between the large-particle urea continuously moving, and curing the large-particle urea after reacting for 10min to form a film; repeating the steps for 5 times, reducing the rotating speed of the coating machine, closing a hot air heating switch, keeping a fan on, naturally cooling hot air, cooling the material in motion for 25min, and cooling coated large-particle urea to 30-35 ℃;
(4) Firstly dispersing nano silicon dioxide in deionized water to uniformly disperse the nano silicon dioxide, adding sodium selenate into the nano silicon dioxide dispersion system, wherein the mass ratio of the nano silicon dioxide to the sodium selenate is 1:2, magnetically stirring for 24 hours, centrifugally collecting mesoporous nano silicon dioxide precipitate loaded with sodium selenate, and drying and marking as MSN@Se;
(5) Dispersing 0.02% of urea mass of MSN@Se in distilled water, dissolving 0.06% of urea mass of sodium alginate in deionized water, stirring by magnetic force until the MSN@Se is completely dissolved, pouring the MSN@Se suspension into a sodium alginate solution, oscillating the mixture by an oscillating machine to form uniform suspension MSN@Se@SA, slowly dripping the MSN@Se@SA into the surfaces of rotating fertilizer particles, forming an outer gel film shell under the condition of continuous rotation, and repeating the operation for 5 times to obtain the double-layer coated controlled release urea.
The coated controlled release urea with the total coated mass accounting for 3.5 percent of the urea mass is prepared by the method, and the coated controlled release urea is a product with the controlled release period of 90 days.
Experimental example: and (3) testing the effect of the nitrogenous fertilizer synergist modified coated controlled release urea.
The test is carried out in 2020-2021 in a corn technological innovation garden (36.09 DEG N,117.09 DEG E) in Huang-Huai-Hai area of Shandong agricultural university and a large venturi test field in Taian Dai Yue area, the local climate type is a temperate semi-moist continental monsoon climate, the soil type in the test area is brown loam, and the content (0-20 cm) of basic nutrients before sowing is 11.84 g/kg of organic matters, 116.65 mg/kg of alkaline hydrolysis nitrogen, 34.19 mg/kg of quick-acting phosphorus, 156.27 mg/kg of quick-acting potassium, 1.73g/kg of total nitrogen and pH 7.32.
The Denghai 605 (DH 605) is selected as the test materialSowing in the middle and upper ten days of 6 months, and planting density of 67500 plants/hm 2 The area of the test cell is 3m multiplied by 9m, the row spacing is 0.6m, the test cell is planted at equal row spacing, each treatment is repeated three times, and the cells are arranged randomly. Different nitrogen application amounts (0, N1:210 kg N hm) are set by adopting a crack area test design -2 、N2:168 kg N hm -2 ) As a primary zone factor, different inhibitor treatments were set as secondary zone factors, PCU1: coated controlled release urea with nitrification inhibitor (dicyandiamide, DCD), PCU2: coated controlled release urea with addition of urease inhibitor (N-butylthiophosphoric triamide, NBPT), PCU3: coated controlled release urea with dcd+nbpt was added. The inhibitor is applied according to the dosage of 0.06 percent of urea, the inhibitor is coated after being coated with urea, the coated urea coating material is an inner layer high polymer film and an outer layer modified gel film, and the controlled release period is 30 days. The proportion of the coated fertilizer is N:P 2 O 5 :K 2 O=28:7:9, the nitrogen control ratio is 30%, the phosphorus-potassium fertilizer is applied, and all types of fertilizer are applied on a basal basis at one time. The specific test treatments are shown in table 1:
table 1 test treatment
Sample collection and measurement method:
determination of nitrogen accumulation amount: the total nitrogen content of the corn adopts H 2 SO 4 -H 2 O 2 Digestion is carried out by a semi-trace Kjeldahl nitrogen determination method.
Soil nitrate and ammonium nitrogen determination: soil samples (60 cm deep) were randomly selected during the V6, VT and R6 periods, and were packed into clear bags in three layers (20 cm per layer) with 3 randomly selected treatments. The soil sample was leached with 1M KCL solution and then the nitrate Nitrogen (NH) of each layer of soil was measured using a continuous flow analyzer 4 + -N) and ammonium nitrogen (NO 3 - -N) concentration.
Harvesting, measuring yield and checking: the number of spikes per hectare was determined using field trait investigation. 30 ears are randomly selected from each cell, and the ear length, the ear thickness, the bald tip length, the ear number, the row grain number, the hundred grain weight, the ear grain weight and the like of each ear are examined.
Test results: among the yield constituent factors, the controlled release fertilizer has the greatest influence on the grain number after being matched with the nitrogenous fertilizer synergist; after the two nitrogen fertilizer synergists are applied simultaneously, the yield of summer corns is obviously improved, and the effect is most obvious; the single nitrogenous fertilizer synergist can be applied to improve the summer corn yield, but the difference is not obvious; under the condition of reducing nitrogen by 20%, the synergistic effect of the nitrogen fertilizer by the combined application is improved compared with the yield of normal nitrogen application treatment, wherein the effect of the combined application of two nitrogen fertilizer synergistic agents is best; the yield of urea after nitrogen reduction and synergistic agent treatment can reach the normal nitrogen treatment effect of the controlled release fertilizer. From the two-year test results (Table 2), the application of the improved coated controlled release urea of the nitrogen fertilizer synergist significantly improves the yield of summer corns. Compared with CK, the yield of the improved coated controlled release urea treatment of the nitrogen fertilizer synergist is averagely improved by 8.82% -13.04%. Wherein the yield increasing effect of N1PCU3 is most remarkable, and the yield of summer corn is improved by 13.04% compared with CK treatment; the yield of N1PCU1 and N2PCU2 is increased by 8.82% and 10.05% respectively compared with CK, and the difference of the yields of the two fertilization treatments is not obvious. The spike number of N1PCU1, N1PCU2 and N1PCU3 is respectively improved by 4.88%, 5.00% and 5.54% compared with CK, wherein the spike number of N1PCU3 treatment is improved most remarkably; from thousand kernel weight, the treatments for N1PCU1, N1PCU2 and N1PCU3 were increased by 2.82%, 2.91% and 5.68%, respectively, as compared to CK. The change trend of the two-year test results is consistent.
TABLE 2 summer corn yield and formation factors for different fertilizer treatments
From table 3, it can be seen that both PFPN and AEN of controlled release fertilizer formulation synergist treatment were significantly higher than conventional controlled release fertilizer treatment. PFPN and AEN of the nitrogen-reduced 20% treatment were significantly higher than normal nitrogen application treatment. Nitrogen reduction treatment can improve nitrogen index such as nitrogen fertilizer agronomic utilization efficiency, nitrogen fertilizer bias productivity, nitrogen fertilizer utilization efficiency and the like of summer corns; under the same nitrogen level, the nitrogen fertilizer synergist can be applied to improve various nitrogen indexes, wherein the effect of applying the two nitrogen fertilizer synergists is optimal, the nitrogen fertilizer utilization efficiency is averagely improved by 44.81%, and after the nitrogen reduction treatment, the nitrogen fertilizer utilization efficiency of applying the two nitrogen fertilizer synergists is averagely improved by 74.86%.
TABLE 3 Effect of summer corn treated with different fertilizers on the Nitrogen fertilizer utilization efficiency of summer corn
As shown in Table 4, the improvement treatment of the nitrogen fertilizer synergist improves the nitrate and ammonium nitrogen contents of the soil surface layer in each period, effectively reduces leaching of nitrate nitrogen caused by excessive content in the early period, and ensures that the inorganic nitrogen content of the soil is maintained at a higher level in the flowering period and after the flowering period. In the summer corn jointing period, the inorganic nitrogen content of the soil layer with the length of 0-20cm treated by the N1PCU4 is lower than that of the nitrogenous fertilizer synergistic agent improvement treatment, and the nitrate nitrogen content of the cultivated layer with the length of 20-40cm and 40-60cm is higher than that of the nitrogenous fertilizer synergistic agent treatment, which shows that the nitrogenous fertilizer synergistic agent improvement treatment obviously improves the holding effect of the nitrate nitrogen on the cultivated layer with the length of 0-20cm and reduces the nitrate nitrogen leaching loss of the cultivated layer with the length of 20-40cm and 40-60 cm. The coated urea modified by the nitrogen fertilizer synergist can meet the fertilizer requirement rule of corn by regulating and controlling the release of nitrogen through the synergist and the coating. In the middle and later stages of the growing process of summer corns, the inorganic nitrogen content of the soil cultivation layers of different treatments after the improvement of the nitrogen fertilizer synergist is higher than that of the conventional controlled release fertilizer treatment, the inorganic nitrogen gradually decreases along with the depth of the soil, and the effect of the improvement of the nitrogen fertilizer synergist on the retention of the inorganic nitrogen in the soil is better than that of N1PCU4, wherein the effect of the treatment of N1PCU3 is the best.
TABLE 4 inorganic Nitrogen content (mg N/Kg) of soil for 0-60 plough layers under different treatments
Yield profit (Yuanhm) -2 ) =seed yield (kg hm) -2 ) X market price (Yuan kg) -1 ）
Economic benefit (Yuanhm) -2 ) Yield gain (yuan hm -2 ) Cost input (meta hm -2 ）
As can be seen from the following Table 5, the nitrogen fertilizer synergist is applied to improve the yield and economic benefit of summer corn compared with the common coated urea, wherein the synergistic application economic benefit of the nitrification inhibitor and the urease inhibitor is higher than that of the single nitrogen fertilizer synergist. The improved coated controlled release urea of the nitrogen fertilizer synergist improves the regulation and control of urea in soil, can keep a good yield increasing effect when reducing 20% of nitrogen, can reduce the input cost of fertilizer and environmental pressure, and simultaneously can ensure the yield benefit, the treated N1PCU3 added with two inhibitors has increased yield by 1524 yuan/hectare compared with the conventional coated controlled release urea N1PCU4, and the N2PCU3 has increased yield by 1072 yuan/hectare compared with the N1PCU4 after reducing 20% of nitrogen. Therefore, although the investment cost of the improved fertilizer is slightly increased, the overall economic benefit is obviously improved after the type of fertilizer is applied, and simultaneously, the loss of nitrogen in soil and the emission of farmland greenhouse gases are reduced, and the environmental pressure is lightened.
TABLE 5 summer corn yield and economic benefits for different fertilizer treatments
Wherein, the controlled release urea is 3500 yuan t -1 The method comprises the steps of carrying out a first treatment on the surface of the Urea, 2800 yuan t -1 The method comprises the steps of carrying out a first treatment on the surface of the 28-7-9 composite controlled release fertilizer (30 d) 3650 t -1 (II), (III), (V), (; 1800 yuan t of 0-7-9 phosphorus-potassium fertilizer -1 The method comprises the steps of carrying out a first treatment on the surface of the DCD,100 yuan kg -1 The method comprises the steps of carrying out a first treatment on the surface of the NBPT,150 yuan kg -1 . The local market price of corn is: 2.68 yuan kg -1 . Other field management of each treatment is consistent, and the cost of seeds, pesticides, machinery and the like is the same and is not included in the calculation.
Further research also shows that compared with the treatment of applying common fertilizer, the treatment of applying sodium selenate and the treatment of applying the multifunctional double-layer coated fertilizer respectively increase the yield by 59.02 percent and 170.30 percent, and the treatment of applying the multifunctional coated fertilizer can promote the growth and development of corn and improve the fruit yield; meanwhile, the treatment of applying the multifunctional double-layer coated fertilizer also increases the content of vitamin C and anthocyanin in fruits, reduces the content of nitrate and improves the quality of the fruits. The selenium content in corn fruits with the multifunctional double-layer coated fertilizer is improved by 4.8 times compared with the treatment with the quick-acting selenium fertilizer, and the selenium utilization rate of the treatment with the multifunctional double-layer coated fertilizer is improved by 3.8 times compared with the treatment with the quick-acting selenium fertilizer, so that the accumulation of selenium in the fruits and the nutrient utilization rate are obviously improved.
Claims (7)
1. The preparation method of the improved double-layer coated controlled release urea of the nitrogenous fertilizer synergist is characterized by comprising the following steps:
(1) Starting a coating machine, and preheating large-particle urea in a rotary drum;
(2) Preparing a nitrification inhibitor into a solution according to 0.03-0.06% of the mass of urea, spraying the nitrification inhibitor solution on the surface of the urea in a coating machine, uniformly coating, keeping the temperature of the urea at 60-65 ℃ after the water is completely evaporated, adding urease inhibitor powder according to the addition amount of 0.03-0.06% of the mass of urea, completely melting the urease inhibitor, uniformly coating on the surface of the urea, and cooling to 50-55 ℃;
(3) Weighing a proper amount of polyester polyol and isocyanate which are heated to be in a liquid state, adding the polyester polyol and the isocyanate into a container, mixing to prepare a coating agent, uniformly dripping the coating agent with the mass of 0.3% -0.6% of urea on the surface of large-particle urea moving in a coating machine, reacting for 5-10min, and curing to form a film; repeating the above operation for 2-5 times, cooling the material in motion for 15-25min, and cooling the coated large-particle urea to 30-35 ℃ to form an inner coating;
(4) Firstly dispersing nano silicon dioxide in deionized water to uniformly disperse the nano silicon dioxide, adding sodium selenate into the nano silicon dioxide dispersion system, wherein the mass ratio of the nano silicon dioxide to the sodium selenate is 1:1.5-2.5, magnetically stirring for 20-30h, centrifugally collecting mesoporous nano silicon dioxide precipitate loaded with sodium selenate, and drying and marking as MSN@Se;
(5) Dispersing 0.01% -0.02% of MSN@Se by mass of urea in distilled water, dissolving 0.03% -0.06% of sodium alginate by mass of urea in deionized water, stirring by magnetic force until the sodium alginate is completely dissolved, pouring MSN@Se suspension into sodium alginate solution, oscillating the mixture by an oscillating machine to form uniform suspension MSN@Se@SA, slowly dripping MSN@Se@SA into the surfaces of rotating fertilizer particles, forming an outer gel film shell under the condition of continuous rotation, and repeating the operation for 2-5 times to obtain the double-layer coated controlled release urea.
2. The method for preparing the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist according to claim 1, which is characterized by comprising the following steps: the operation parameters of the coating machine in the step (1) are that the rotating speed is set to be 50rpm, the hot air temperature is set to be 85-95 ℃, and when the large-particle urea is preheated to 58-62 ℃, the hot air temperature is adjusted to be 65-70 ℃.
3. The method for preparing the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist according to claim 1, which is characterized by comprising the following steps: the preparation method of the nitrification inhibitor solution in the step (2) comprises the following steps: the nitrification inhibitor is prepared by the following components in percentage by mass: 10 is added into 80 ℃ hot water to prepare a solution.
4. The method for preparing the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist according to claim 1, which is characterized by comprising the following steps: the nitrification inhibitor is dicyandiamide, and the urease inhibitor is N-butyl thiophosphoric triamide.
5. The method for preparing the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist according to claim 1, which is characterized by comprising the following steps: the total mass of the coating accounts for 1.5% -3.5% of the mass of urea.
6. The method for preparing the improved double-layer coated controlled release urea of the nitrogen fertilizer synergist according to claim 1, which is characterized by comprising the following steps: the mass ratio of the polyester polyol to the isocyanate is 5:3.
7. The improved double-layer coated controlled release urea of a nitrogen fertilizer synergist prepared by the method of any one of claims 1-6.
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