Multifunctional compound fertilizer and preparation method thereof

Abstract

The invention provides a multifunctional compound fertilizer and a preparation method thereof, and belongs to the technical field of high-tower compound fertilizers. The multifunctional compound fertilizer comprises urea, monopotassium phosphate, potassium chloride, monoammonium phosphate, polyglutamic acid, liquid sodium silicate, light burning powder, styrene-acrylic emulsion and a waterproof agent, and is prepared by the following steps: after melting the urea, sequentially adding the potassium chloride, the monopotassium phosphate, the light burning powder, the liquid sodium silicate, the polyglutamic acid and the monoammonium phosphate; the preparation method comprises the following steps: mixing the raw materials, emulsifying and granulating to obtain material particles, coating the material particles with a styrene-acrylic emulsion and a waterproof agent, and finally carrying out anti-caking treatment to obtain the multifunctional compound fertilizer. The obtained multifunctional compound fertilizer has the effects of being good in slow release effect, promoting phosphorus and increasing efficiency, preventing potassium loss, promoting fertilizer efficiency increase, improving soil fertility, improving soil physical and chemical properties, improving crop quality and yield and enhancing crop disease resistance and stress resistance.

Description

Technical Field

[0001] The invention relates to the technical field of high-tower compound fertilizers, and in particular to a multifunctional compound fertilizer and a preparation method thereof. Background Art

[0002] The high tower granulation process refers to heating and melting solid urea or ammonium nitrate phosphate into a molten liquid, and then adding the corresponding potassium fertilizer, monoammonium phosphate and filler into the molten liquid to make a mixed slurry; the mixed slurry is sprayed and granulated through a high tower granulator. During the granulated material descending from the high tower, it interacts with the gas resistance rising from the bottom of the tower, exchanges heat with the gas, and falls to the bottom of the tower. The granular material at the bottom of the tower is cooled, screened and anti-caking treated to obtain granular compound fertilizer.

[0003] However, due to the process defects of the high tower granulation process itself and the composition of the raw materials of the compound fertilizer, most of the compound fertilizers obtained by high tower granulation do not have a slow-release effect. They only contain nitrogen, phosphorus, and potassium macroelements, but do not contain trace elements necessary for crop growth. The above problems make the high tower fertilizer products have a single function and are difficult to adapt to different soil conditions. They cannot effectively improve the fertilizer nutrient utilization rate, improve crop quality, and improve soil structure. Therefore, it is of great significance to provide a multifunctional high tower compound fertilizer with good slow-release effect and improved crop quality. Summary of the invention

[0004] The object of the present invention is to provide a multifunctional compound fertilizer and a preparation method thereof, wherein the multifunctional compound fertilizer has good slow-release effect, promotes phosphorus efficiency, prevents potassium loss, and promotes fertilizer efficiency, improves soil fertility, improves soil physical and chemical properties, improves crop quality and yield, and enhances crop disease resistance and stress resistance.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A multifunctional compound fertilizer, comprising urea, potassium dihydrogen phosphate, potassium chloride, monoammonium phosphate, polyglutamic acid, liquid sodium silicate, light-burned powder, styrene-acrylic emulsion and a waterproofing agent;

[0007] The mass percentage of urea in the total input raw materials is 42% to 50%, the mass percentage of potassium dihydrogen phosphate in the total input raw materials is 6% to 10%, the mass percentage of potassium chloride in the total input raw materials is 10% to 16%, the mass percentage of monoammonium phosphate in the total input raw materials is 16% to 25%, the mass percentage of polyglutamic acid in the total input raw materials is 6% to 8%, the mass percentage of liquid sodium silicate in the total input raw materials is 3% to 4%, the mass percentage of light-burned powder in the total input raw materials is 3% to 5%, and the mass percentage of styrene-acrylic emulsion and waterproofing agent in total is 2% to 3%.

[0008] Preferably, the mass ratio of the styrene acrylic emulsion to the waterproofing agent is 1:1.

[0009] Preferably, the mass ratio of the liquid sodium silicate to polyglutamic acid is 1:2.

[0010] Preferably, the pH value of the liquid sodium silicate is 8.5-9.

[0011] Preferably, the pH value of the polyglutamic acid is 5-6.

[0012] The present invention also provides a method for preparing the multifunctional compound fertilizer, comprising the following steps:

[0013] Urea is added into a melting tank for melting, and the melted urea overflows into a primary mixing tank;

[0014] Adding potassium chloride, potassium dihydrogen phosphate and light-burned powder into a primary mixing tank and mixing with the urea, and the mixed molten materials overflow into a secondary mixing tank;

[0015] Adding liquid sodium silicate and polyglutamic acid into a blender for first mixing to obtain a mixed solution;

[0016] placing the mixed solution and monoammonium phosphate in a secondary mixing tank for second mixing with the molten material to obtain a mixed molten slurry;

[0017] emulsifying the mixed molten slurry, granulating it, and cooling it to obtain cooled material particles;

[0018] The cooled material particles are screened, and qualified material particles obtained by screening are added to a cooler, and unqualified materials are returned to a primary mixing tank;

[0019] Spraying the styrene acrylic emulsion and the waterproofing agent onto the qualified material particles at the entrance of the cooler in an atomized manner, coating the surfaces of the qualified material particles to obtain coated material particles;

[0020] The coated material particles are added into a wrapping machine and packaged after anti-caking treatment.

[0021] Preferably, the temperature of the melting tank is 115°C to 120°C, the temperature of the primary mixing tank is 105°C to 110°C, and the temperature of the secondary mixing tank is 95°C to 100°C.

[0022] Preferably, the first mixing time is 4 to 5 minutes, and the pH value of the mixed solution is 6 to 7; the second mixing time is less than 4.5 minutes; and the temperature of the cooled material particles is less than 65°C.

[0023] Preferably, the screening includes coarse screen screening and fine screen screening, the diameter of the coarse screen hole is 4.5 mm, and the diameter of the fine screen hole is 2.0 mm.

[0024] Preferably, the particle size of the qualified material particles is 2-4.5 mm, and the particle size of the unqualified material particles is greater than 4.5 mm or less than 2 mm.

[0025] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0026] 1) The light-burned powder in the present invention is porous, loose and has strong adsorption capacity. The liquid sodium silicate has the characteristics of large specific area after solidification, can block capillary channels, and improve material density and strength. After high-tower granulation, a multi-layer hard mesh inner membrane shell is formed inside the fertilizer particles, so as to achieve the effect of adsorbing and fixing nutrients, that is, it can achieve nitrogen control and slow release, promote phosphorus efficiency and prevent potassium loss; in addition, both the light-burned powder and the liquid sodium silicate can be degraded in the soil, and are rich in magnesium, silicon and other trace elements necessary for crop growth, which is conducive to promoting crop growth.

[0027] 2) The present invention uses styrene acrylic emulsion and waterproofing agent as coating materials, which not only can achieve a good slow-release effect of the fertilizer, but also will not cause secondary pollution to the soil compared with other slow-release fertilizers using chemical coating agents, and is more environmentally friendly.

[0028] 3) The multifunctional compound fertilizer granules of the present invention combine two slow-release fertilizer production technologies: surface coating and built-in adsorption and fixation of nutrient substances. The obtained fertilizer granules have the advantages of good slow-release effect and low cost.

[0029] 4) The liquid sodium silicate in the present invention is an alkaline material, and the pH value thereof can be adjusted by using polyglutamic acid to make it better adapt to the soil environment. At the same time, polyglutamic acid has the functions of buffering the pH value of the soil, improving the utilization rate of fertilizers and improving the stress resistance of crops.

[0030] 5) The multifunctional compound fertilizer of the present invention has a good slow-release effect, that is, it contains nitrogen, phosphorus, potassium macroelements required by crops, and also contains silicon, magnesium and other trace elements and polyglutamic acid; it has the effects of promoting fertilizer efficiency, increasing soil fertility, improving soil physical and chemical properties, improving crop quality and yield, and enhancing crop disease resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the process for preparing the multifunctional compound fertilizer in Example 1. DETAILED DESCRIPTION

[0032] A multifunctional compound fertilizer, comprising urea, potassium dihydrogen phosphate, potassium chloride, monoammonium phosphate, polyglutamic acid, liquid sodium silicate, light-burned powder, styrene-acrylic emulsion and a waterproofing agent;

[0033] The mass percentage of urea in the total input raw materials is preferably 42% to 50%, the mass percentage of potassium dihydrogen phosphate in the total input raw materials is preferably 6% to 10%, the mass percentage of potassium chloride in the total input raw materials is preferably 10% to 16%, the mass percentage of monoammonium phosphate in the total input raw materials is preferably 16% to 25%, the mass percentage of polyglutamic acid in the total input raw materials is preferably 6% to 8%, the mass percentage of liquid sodium silicate in the total input raw materials is preferably 3% to 4%, the mass percentage of light-burned powder in the total input raw materials is preferably 3% to 5%, and the mass percentage of styrene-acrylic emulsion and waterproofing agent in the total input raw materials is preferably 2% to 3%.

[0034] The mass percentage of urea in the total amount of raw materials input is further preferably 45% to 50%, the mass percentage of potassium dihydrogen phosphate in the total amount of raw materials input is further preferably 8% to 10%, the mass percentage of potassium chloride in the total amount of raw materials input is further preferably 13% to 16%, the mass percentage of monoammonium phosphate in the total amount of raw materials input is further preferably 20% to 25%, the mass percentage of polyglutamic acid in the total amount of raw materials input is further preferably 7% to 8%, the mass percentage of liquid sodium silicate in the total amount of raw materials input is further preferably 3.5% to 4%, the mass percentage of light-burned powder in the total amount of raw materials input is further preferably 4% to 5%, and the mass percentage of styrene-acrylic emulsion and waterproofing agent in the total amount of raw materials input is further preferably 2.5% to 3%.

[0035] The mass percentage of urea in the total input raw materials is more preferably 47% to 50%, the mass percentage of potassium dihydrogen phosphate in the total input raw materials is more preferably 9% to 10%, the mass percentage of potassium chloride in the total input raw materials is more preferably 15% to 16%, the mass percentage of monoammonium phosphate in the total input raw materials is more preferably 23% to 25%, the mass percentage of polyglutamic acid in the total input raw materials is more preferably 7.5% to 8%, the mass percentage of liquid sodium silicate in the total input raw materials is more preferably 3.8% to 4%, the mass percentage of light-burned powder in the total input raw materials is more preferably 4.5% to 5%, and the mass percentage of styrene-acrylic emulsion and waterproofing agent in the total input raw materials is more preferably 2.8% to 3%.

[0036] The invention contains nitrogen, phosphorus and potassium macroelements required by crops, as well as trace elements such as calcium and polyglutamic acid; it has the effects of promoting fertilizer efficiency, increasing soil fertility, improving soil physical and chemical properties, improving crop quality and yield, and enhancing crop disease resistance.

[0037] In the present invention, the mass ratio of the styrene acrylic emulsion to the waterproofing agent is preferably 1:1.

[0038] In the present invention, the mass ratio of the liquid sodium silicate to polyglutamic acid is preferably 1:2.

[0039] In the present invention, the pH value of the liquid sodium silicate is preferably 8.5-9, and more preferably 8.7-9.

[0040] In the present invention, the pH value of the polyglutamic acid is preferably 5-6, and more preferably 5.5-6.

[0041] In the present invention, unless otherwise specified, the required raw materials for preparation are all commercially available products well known to those skilled in the art.

[0042] The present invention also provides a method for preparing the multifunctional compound fertilizer, comprising the following steps:

[0043] Urea is added into a melting tank for melting, and the melted urea solution overflows into a primary mixing tank;

[0044] In the present invention, the temperature of the melting tank is preferably 115°C to 120°C, and more preferably 118°C to 120°C;

[0045] Potassium chloride, potassium dihydrogen phosphate and light-burned powder are added to the primary mixing tank and mixed with urea, and the mixed molten materials overflow into the secondary mixing tank;

[0046] In the present invention, the temperature of the primary mixing tank is preferably 105°C to 110°C, and more preferably 108°C to 110°C;

[0047] Adding liquid sodium silicate and polyglutamic acid into a blender for first mixing to obtain a mixed solution;

[0048] In the present invention, the first mixing time is preferably 4 to 5 minutes, more preferably 4.5 to 5 minutes; the pH value of the liquid sodium silicate is preferably 8.5 to 9, more preferably 8.7 to 9, the pH value of the polyglutamic acid is preferably 5 to 6, more preferably 5.5 to 6; the pH value of the mixed solution is preferably 6 to 7, more preferably 6.5 to 7;

[0049] The light-burned powder in the present invention is porous, loose and has strong adsorption capacity. The liquid sodium silicate has the characteristics of large specific area after solidification, can block capillary channels, and improve material density and strength. After high-tower granulation, a multi-layer hard mesh inner membrane shell is formed inside the fertilizer particles to achieve the effect of adsorbing and fixing nutrients, that is, it can achieve nitrogen control and slow release, promote phosphorus efficiency and prevent potassium loss.

[0050] The liquid sodium silicate in the present invention is an alkaline material, and the pH value thereof can be adjusted by using polyglutamic acid to make it better adapt to the soil environment. Meanwhile, polyglutamic acid has the functions of buffering the pH value of the soil, improving the utilization rate of fertilizers and improving the stress resistance of crops.

[0051] placing the mixed solution and monoammonium phosphate in a secondary mixing tank for second mixing with the molten material to obtain a mixed molten slurry;

[0052] In the present invention, the second mixing time is preferably less than 4.5 min.

[0053] emulsifying the mixed molten slurry, granulating it, and cooling it to obtain cooled material particles;

[0054] In the present invention, the temperature of the cooled material particles is preferably <65°C;

[0055] The present invention does not impose any particular limitation on the methods of emulsification and granulation, and any technical means well known to those skilled in the art may be used.

[0056] The cooled material particles are screened, and qualified material particles obtained by screening are added to a cooler, and unqualified materials are returned to a primary mixing tank;

[0057] In the present invention, the screening preferably includes coarse screen screening and fine screen screening, the coarse screen hole diameter is preferably 4.5mm, the fine screen hole diameter is preferably 2.0mm, the particle size of the qualified material particles is preferably 2-4.5mm, and the particle size of the unqualified material particles is preferably greater than 4.5mm or less than 2mm.

[0058] The present invention returns unqualified materials to the mixing tank for recycling and continues production, thereby reducing production costs.

[0059] Spraying the styrene acrylic emulsion and the waterproofing agent onto the qualified material particles at the entrance of the cooler in an atomized manner, coating the surfaces of the screened qualified material particles to obtain coated material particles;

[0060] The invention adopts styrene acrylic emulsion and waterproofing agent as coating materials, which not only can achieve good slow-release effect of fertilizer, but also will not cause secondary pollution to soil compared with other slow-release fertilizers adopting chemical coating agents, and is more environmentally friendly.

[0061] The coated material particles are added into a wrapping machine and packaged after anti-caking treatment.

[0062] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0063] Example 1

[0064] 1) 42 kg of urea was added into the melting tank for melting. The melted urea solution overflowed into the primary mixing tank. The temperature of the overflow tank was 115° C. and the temperature of the primary mixing tank was 105° C.;

[0065] 2) 10 kg potassium chloride, 6 kg potassium dihydrogen phosphate and 3 kg light-burned powder are added to the primary mixing tank and mixed with urea. The mixed molten materials overflow into the secondary mixing tank. The temperature of the secondary mixing tank is 95°C.

[0066] 3) adding 3 kg of liquid sodium silicate with a pH value of 8.5 and 6 kg of polyglutamic acid with a pH value of 5 into a blender and mixing for 4 min to obtain a mixed solution with a pH value of 6;

[0067] 4) placing the mixed solution and 16 kg of monoammonium phosphate in a secondary mixing tank and mixing with the molten material for 3 minutes to obtain a mixed molten slurry;

[0068] 5) emulsifying the mixed molten slurry through an emulsifier and spraying and granulating the mixed molten slurry in a granulation tower through a granulator, and then cooling the mixed molten slurry naturally in the granulation tower to obtain material particles having a temperature of less than 65° C. after cooling;

[0069] 6) The cooled material particles are subjected to coarse sieving and fine sieving respectively, the coarse sieving hole particle size is 4.5 mm, the fine sieving hole particle size is 2.0 mm, and the material particles with particle sizes between 2.0 mm and 4.5 mm are qualified material particles. The qualified material particles obtained by screening are added to the cooler, and the unqualified materials are returned to the primary mixing tank;

[0070] 7) Spraying 1 kg of styrene acrylic emulsion and 1 kg of waterproofing agent onto the qualified material particles at the entrance of the cooler in an atomized manner, coating the surfaces of the sieved qualified material particles to obtain coated material particles;

[0071] 8) Adding the coated material particles into a packaging machine, performing anti-caking treatment and then packaging to obtain a multifunctional compound fertilizer.

[0072] Example 2

[0073] 1) 45 kg of urea is added into the melting tank for melting. The melted urea solution overflows into the primary mixing tank. The temperature of the overflow tank is 115°C and the temperature of the primary mixing tank is 105°C.

[0074] 2) 13 kg potassium chloride, 8 kg potassium dihydrogen phosphate and 4 kg light-burned powder are added to the primary mixing tank and mixed with urea. The mixed molten materials overflow into the secondary mixing tank. The temperature of the secondary mixing tank is 95° C.

[0075] 3) adding 3.5 kg of liquid sodium silicate with a pH value of 8.7 and 7 kg of polyglutamic acid with a pH value of 5.5 into a blender and mixing for 4.5 min to obtain a mixed solution with a pH value of 6.5;

[0076] 4) placing the mixed solution and 20 kg of monoammonium phosphate in a secondary mixing tank and mixing with the molten material for 3.5 minutes to obtain a mixed molten slurry;

[0077] 5) emulsifying the mixed molten slurry through an emulsifier and spraying and granulating the mixed molten slurry in a granulation tower through a granulator, and then cooling the mixed molten slurry naturally in the granulation tower to obtain material particles having a temperature of less than 65° C. after cooling;

[0078] 6) The cooled material particles are subjected to coarse sieving and fine sieving respectively, the coarse sieving hole particle size is 4.5 mm, the fine sieving hole particle size is 2.0 mm, and the material particles with particle sizes between 2.0 mm and 4.5 mm are qualified material particles. The qualified material particles obtained by screening are added to the cooler, and the unqualified materials are returned to the primary mixing tank;

[0079] 7) Spraying 1.25 kg of styrene acrylic emulsion and 1.25 kg of waterproofing agent onto the qualified material particles at the entrance of the cooler in an atomized manner, coating the surfaces of the sieved qualified material particles to obtain coated material particles;

[0080] 8) Adding the coated material particles into a packaging machine, performing anti-caking treatment and then packaging to obtain a multifunctional compound fertilizer.

[0081] Example 3

[0082] 1) 47 kg of urea was added into the melting tank for melting. The melted urea solution overflowed into the primary mixing tank. The temperature of the overflow tank was 115° C. and the temperature of the primary mixing tank was 105° C.;

[0083] 2) 15 kg potassium chloride, 9 kg potassium dihydrogen phosphate and 4.5 kg light-burned powder are added to the primary mixing tank and mixed with urea. The mixed molten materials overflow into the secondary mixing tank. The temperature of the secondary mixing tank is 95° C.

[0084] 3) adding 3.8 kg of liquid sodium silicate with a pH value of 9 and 7.6 kg of polyglutamic acid with a pH value of 6 into a blender and mixing for 5 min to obtain a mixed solution with a pH value of 7;

[0085] 4) placing the mixed solution and 23 kg of monoammonium phosphate in a secondary mixing tank and mixing with the molten material for 4 minutes to obtain a mixed molten slurry;

[0086] 5) emulsifying the mixed molten slurry through an emulsifier and spraying and granulating the mixed molten slurry in a granulation tower through a granulator, and then cooling the mixed molten slurry naturally in the granulation tower to obtain material particles having a temperature of less than 65° C. after cooling;

[0087] 6) The cooled material particles are subjected to coarse sieving and fine sieving respectively, the coarse sieving hole particle size is 4.5 mm, the fine sieving hole particle size is 2.0 mm, and the material particles with particle sizes between 2.0 mm and 4.5 mm are qualified material particles. The qualified material particles obtained by screening are added to the cooler, and the unqualified materials are returned to the primary mixing tank;

[0088] 7) Spraying 1.4 kg of styrene acrylic emulsion and 1.4 kg of waterproofing agent onto the qualified material particles at the entrance of the cooler in an atomized manner, coating the surfaces of the sieved qualified material particles to obtain coated material particles;

[0089] 8) Adding the coated material particles into a packaging machine, performing anti-caking treatment and then packaging to obtain a multifunctional compound fertilizer.

[0090] Example 4

[0091] 1) Add 50 kg of urea into the melting tank for melting. The melted urea solution overflows into the primary mixing tank. The temperature of the overflow tank is 115°C and the temperature of the primary mixing tank is 105°C.

[0092] 2) 16 kg potassium chloride, 10 kg potassium dihydrogen phosphate and 5 kg light-burned powder are added to the primary mixing tank and mixed with urea. The mixed molten materials overflow into the secondary mixing tank. The temperature of the secondary mixing tank is 95°C.

[0093] 3) 4 kg of liquid sodium silicate with a pH value of 9 and 8 kg of polyglutamic acid with a pH value of 6 were added to a blender and mixed for 5 minutes to obtain a mixed solution with a pH value of 7;

[0094] 4) placing the mixed solution and 25 kg of monoammonium phosphate in a secondary mixing tank and mixing with the molten material for 4 minutes to obtain a mixed molten slurry;

[0095] 5) emulsifying the mixed molten slurry through an emulsifier and spraying and granulating the mixed molten slurry in a granulation tower through a granulator, and then cooling the mixed molten slurry naturally in the granulation tower to obtain material particles having a temperature of less than 65° C. after cooling;

[0096] 6) The cooled material particles are subjected to coarse sieving and fine sieving respectively, the coarse sieving hole particle size is 4.5 mm, the fine sieving hole particle size is 2.0 mm, and the material particles with particle sizes between 2.0 mm and 4.5 mm are qualified material particles. The qualified material particles obtained by screening are added to the cooler, and the unqualified materials are returned to the primary mixing tank;

[0097] 7) Spraying 1.5 kg of styrene acrylic emulsion and 1.5 kg of waterproofing agent onto the qualified material particles at the entrance of the cooler in an atomized manner, coating the surfaces of the sieved qualified material particles to obtain coated material particles;

[0098] 8) Adding the coated material particles into a packaging machine, performing anti-caking treatment and then packaging to obtain a multifunctional compound fertilizer.

[0099] Application Example 1

[0100] Farmers were set to use the multifunctional compound fertilizer obtained in Example 1 to fertilize the common cucumber demonstration area without applying base fertilizer. From the beginning of cucumber planting, topdressing was combined with drip irrigation, and topdressing was performed every 7 days, for a total of 5 times, with 3.5 kg / mu of multifunctional compound fertilizer applied each time.

[0101] Application Example 2

[0102] Farmers were set to use the multifunctional compound fertilizer obtained in Example 2 to fertilize the common cucumber demonstration area without applying base fertilizer. From the beginning of cucumber planting, topdressing was combined with drip irrigation, and topdressing was performed every 7 days, for a total of 5 times, with 3.5 kg / mu of multifunctional compound fertilizer applied each time.

[0103] Application Example 3

[0104] Farmers were set to use the multifunctional compound fertilizer obtained in Example 3 to fertilize the common cucumber demonstration area without applying base fertilizer. From the beginning of cucumber planting, topdressing was combined with drip irrigation, and topdressing was performed once every 7 days, for a total of 5 times, with 3.5 kg / mu of multifunctional compound fertilizer applied each time.

[0105] Application Example 4

[0106] Farmers were set to use the multifunctional compound fertilizer obtained in Example 4 to fertilize the common cucumber demonstration area without applying base fertilizer. From the beginning of cucumber planting, topdressing was combined with drip irrigation, and topdressing was performed once every 7 days, for a total of 5 times, with 3.5 kg / mu of multifunctional compound fertilizer applied each time.

[0107] Application Comparative Example 1

[0108] Farmers were set to use ordinary compound fertilizers to fertilize the ordinary cucumber demonstration area without applying base fertilizer. From the beginning of cucumber planting, they combined drip irrigation with topdressing, and topdressed once every 7 days, for a total of 5 times. Each time, 5 kg / mu of ordinary compound fertilizer was applied.

[0109] Compared with the comparative example 1, the multifunctional compound fertilizer can increase the yield of cucumber by 623.64 kg per mu on the basis of saving 30% of fertilizer compared with the farmers using ordinary compound fertilizers.

[0110] Compared with the comparative example 1, the multifunctional compound fertilizer can increase the yield of cucumber by 624.25 kg per mu on the basis of saving 30% of fertilizer compared with the farmers using ordinary compound fertilizers.

[0111] Compared with the comparative example 1, the use of multifunctional compound fertilizer can increase the yield of cucumber by 633.61 kg per mu on the basis of saving 30% of fertilizer compared with farmers using ordinary compound fertilizer.

[0112] Compared with the comparative example 1, the use of multifunctional compound fertilizer can increase the yield of cucumber by 640.32 kg per mu on the basis of saving 30% of fertilizer compared with farmers using ordinary compound fertilizer.

[0113] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multifunctional compound fertilizer, characterized in that: The multifunctional compound fertilizer comprises urea, potassium dihydrogen phosphate, potassium chloride, monoammonium phosphate, polyglutamic acid, liquid sodium silicate, light-burned powder, styrene-acrylic emulsion and waterproofing agent; The mass percentage of urea in the total input raw materials is 42% to 50%, the mass percentage of potassium dihydrogen phosphate in the total input raw materials is 6% to 10%, the mass percentage of potassium chloride in the total input raw materials is 10% to 16%, the mass percentage of monoammonium phosphate in the total input raw materials is 16% to 25%, the mass percentage of polyglutamic acid in the total input raw materials is 6% to 8%, the mass percentage of liquid sodium silicate in the total input raw materials is 3% to 4%, the mass percentage of light-burned powder in the total input raw materials is 3% to 5%, and the mass percentage of styrene-acrylic emulsion and waterproofing agent in total is 2% to 3%.

2. The multifunctional compound fertilizer according to claim 1, characterized in that: The mass ratio of the styrene acrylic emulsion to the waterproofing agent is 1:

1.

3. The multifunctional compound fertilizer according to claim 1, characterized in that: The mass ratio of the liquid sodium silicate to polyglutamic acid is 1:

2.

4. The multifunctional compound fertilizer according to claim 1, characterized in that: The pH value of the liquid sodium silicate is 8.5-9.

5. The multifunctional compound fertilizer according to claim 1, characterized in that: The pH value of the polyglutamic acid is 5-6.

6. A method for preparing the multifunctional compound fertilizer according to any one of claims 1 to 5, characterized in that: The following steps are involved: Urea is added into a melting tank for melting, and the melted urea overflows into a primary mixing tank; Adding potassium chloride, potassium dihydrogen phosphate and light-burned powder into a primary mixing tank and mixing with the urea, and the mixed molten materials overflow into a secondary mixing tank; Adding liquid sodium silicate and polyglutamic acid into a blender for first mixing to obtain a mixed solution; placing the mixed solution and monoammonium phosphate in a secondary mixing tank for second mixing with the molten material to obtain a mixed molten slurry; emulsifying the mixed molten slurry, granulating it, and cooling it to obtain cooled material particles; The cooled material particles are screened, and qualified material particles obtained by screening are added to a cooler, and unqualified materials are returned to a primary mixing tank; Spraying the styrene acrylic emulsion and the waterproofing agent onto the qualified material particles at the entrance of the cooler in an atomized manner, coating the surfaces of the qualified material particles to obtain coated material particles; The coated material particles are added into a wrapping machine and packaged after anti-caking treatment.

7. The method for preparing the multifunctional compound fertilizer according to claim 6, characterized in that: The temperature of the melting tank is 115°C to 120°C, the temperature of the primary mixing tank is 105°C to 110°C, and the temperature of the secondary mixing tank is 95°C to 100°C.

8. The method for preparing the multifunctional compound fertilizer according to claim 6, characterized in that: The first mixing time is 4 to 5 minutes, and the pH value of the mixed solution is 6 to 7; the second mixing time is less than 4.5 minutes; and the temperature of the cooled material particles is less than 65°C.

9. The method for preparing the multifunctional compound fertilizer according to claim 6, characterized in that: The screening includes coarse screen screening and fine screen screening, the diameter of the coarse screen hole is 4.5mm, and the diameter of the fine screen hole is 2.0mm.

10. The method for preparing the multifunctional compound fertilizer according to claim 6, characterized in that: The particle size of the qualified material particles is 2-4.5 mm, and the particle size of the unqualified material particles is greater than 4.5 mm or less than 2 mm.

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