High-efficiency growth-promoting regulating compound fertilizer, preparation method and application thereof

Abstract

The application provides a high-efficiency growth-promoting and regulating type compound fertilizer as well as a preparation method and application thereof, and belongs to the technical field of biological compound fertilizers.The raw materials of the compound fertilizer include biological bacteria, biological bacteria protective agent, slow-release carrier, nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, slow-release regulator microcapsule and diatomite; the compound fertilizer has a three-layer structure; the inner core of the compound fertilizer is a core particle coated by polyvinylpyrrolidone, which is prepared by granulating biological bacteria mixed with biological bacteria protective agent by using starch and pregelatinized starch; the middle layer is a middle coating layer bonded by polyvinyl alcohol, which is prepared by mixing diatomite, nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer; and the outer layer is an outer coating layer bonded by polyvinyl alcohol, which is prepared by mixing diatomite and slow-release regulator microcapsule.In the application, the biological bacteria and protective agent core particle are combined with the chemical fertilizer in the middle layer and the slow-release regulator microcapsule in the outer layer, so that the effects of nutrient supply, plant growth regulation and soil improvement are achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bio-complex fertilizers, and particularly relates to a high-efficiency growth-promoting and regulating type complex fertilizer as well as a preparation method and application thereof. BACKGROUND

[0002] Chemical fertilizers have dominated agricultural production in the past few decades. Their advantages are obvious, and they can quickly provide crops with main nutrients such as nitrogen, phosphorus, and potassium, effectively improve the soil nutrient supply condition, promote crop growth, and greatly increase crop yield. For example, nitrogen fertilizer can make crops grow lush, phosphorus fertilizer can promote root development and flowering and fruiting, and potassium fertilizer can enhance the lodging resistance and disease resistance of crops. However, long-term and large-scale use of chemical fertilizers has also brought a series of serious problems. On the one hand, the utilization rate of chemical fertilizers is low, and a large amount of unabsorbed nutrients are lost to the environment, causing water eutrophication, leading to excessive algae reproduction in lakes and rivers, and destroying the balance of aquatic ecosystems. On the other hand, long-term dependence on chemical fertilizers can cause soil compaction and acidification, reduce soil organic matter content, destroy soil structure, affect the water and fertilizer retention capacity and aeration of the soil, and thus reduce crop quality and yield.

[0003] Microbial fertilizer is a new type of fertilizer, which has attracted widespread attention due to its unique action mechanism and environmental protection characteristics. Microbial fertilizer is added with a large amount of beneficial microorganisms such as nitrogen-fixing bacteria, phosphorus-dissolving bacteria, and potassium-dissolving bacteria. Nitrogen-fixing bacteria can convert atmospheric nitrogen into nitrogen that can be absorbed by plants, and phosphorus-dissolving bacteria and potassium-dissolving bacteria can convert insoluble phosphorus and potassium in the soil into available forms, thereby improving the availability of soil nutrients. In addition, beneficial microorganisms can produce plant growth hormones, vitamins, and other substances during their reproduction and metabolism in the soil, stimulate crop growth, enhance the stress resistance of crops, and improve the resistance of crops to pests and diseases. Moreover, microbial fertilizer can improve the soil microbial community structure, increase the number of beneficial microorganisms in the soil, promote the formation of soil aggregate structure, improve the soil physical and chemical properties, and enhance soil fertility. However, microbial fertilizer also has limitations. Its nutrient content is relatively low, and it cannot fully meet the large nutrient demand of crops during the vigorous growth period. The fertilizer efficiency is slow, and the promotion effect on crop growth is not as obvious as that of chemical fertilizer in the short term.

[0004] Based on the advantages and disadvantages of chemical fertilizer and microbial fertilizer, the development of a compound fertilizer of microbial fertilizer and chemical fertilizer has become an inevitable trend. This compound fertilizer combines the advantages of both, which can theoretically quickly provide crops with sufficient nutrients to meet the needs of crops at different growth stages, and improve the soil environment through the action of microorganisms to increase fertilizer utilization rate, reduce the use of chemical fertilizers, and reduce environmental pollution, thereby achieving sustainable development of agriculture. However, in practical application, the compound fertilizer still has the following problems:

[0005] (1) Microbial survival problem: high temperature, high moisture and high salinity environment in the production process of chemical fertilizer, which is easy to lead to the difficulty of microbial survival.

[0006] (2) Poor fertilizer efficiency: although microbial fertilizer can improve soil environment and improve fertilizer utilization to some extent, but in the vigorous growth period of crops, its nutrient supply is poor, which cannot meet the large demand of crops for nutrients in time.

[0007] Therefore, it is necessary to continuously improve and develop more efficient compound fertilizer to meet the needs of crop growth and soil improvement. SUMMARY

[0008] In view of the problems of microbial survival and poor fertilizer efficiency of the prior art compound fertilizer, the present application is a kind of high-efficiency growth promoting and regulating type compound fertilizer and its preparation method and application, which innovatively adds biological bacteria and protective agent core particles, combines with intermediate layer of nitrogen, phosphorus and potassium fertilizer, and outer layer of slow-release regulator microcapsule, realizes the effects of nutrient supply, plant growth regulation and soil improvement; The preparation process ensures the uniformity and stability of the fertilizer particles through special granulation process, and at the same time makes the slow-release regulator and beneficial microbial flora maintain activity in the fertilizer. The specific technical scheme is as follows:

[0009] A kind of high-efficiency growth promoting and regulating type compound fertilizer, the compound fertilizer includes the following mass fraction of raw materials: biological bacteria 0.1 parts to 0.5 parts, biological bacteria protective agent 0.3 parts to 0.8 parts, slow-release carrier 0.5 parts to 1 part, nitrogen fertilizer 20 parts to 25 parts, phosphorus fertilizer 15 parts to 20 parts, potassium fertilizer 10 parts to 15 parts, slow-release regulator microcapsule 0.15 parts to 0.25 parts, diatomite 20 parts to 30 parts. The compound fertilizer is divided into three layers. The core is biological bacteria protective agent mixed with biological bacteria, then granulated by starch and pregelatinized starch, and then coated with polyvinylpyrrolidone core particles. The intermediate layer is diatomite mixed with nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer, which is bonded by polyvinyl alcohol. The outer layer is diatomite mixed with slow-release regulator microcapsule, which is bonded by polyvinyl alcohol. The biological bacteria protective agent is a product obtained by jointly enzymolysis of sodium alginate, wet chitosan and pea protein powder by alginate lyase, chitosanase and papain.

[0010] In the above compound fertilizer, the biological bacteria include Bacillus subtilis, Bacillus megaterium and nitrogen-fixing bacteria, and the mass ratio is Bacillus subtilis: Bacillus megaterium: nitrogen-fixing bacteria = (30-40): (25-35): (20-30).

[0011] The preparation method of the biological bacteria protective agent comprises the following steps: according to the mass ratio of sodium alginate:wet chitosan:pea protein powder=(2-3):(3-5):(5-8), a base material is prepared, 10-12 times the mass of water of the base material is added, 0.5-1% of the mass of sodium alginate of alginate lyase is added, 1-1.5% of the mass of wet chitosan of chitosanase is added, 1-2% of the mass of soybean protein of papain is added, enzymolysis is carried out at 40-50°C for 3-5h, enzyme inactivation is carried out at 90-100°C for 10-20min, concentration and drying are carried out, and the biological bacteria protective agent is obtained.

[0012] In the preparation method of the biological bacteria protective agent, the wet chitosan is obtained by immersing chitosan in 0.1-0.3mol / L dilute hydrochloric acid solution for 2-3h, washing to neutral with deionized water, and then extracting by filtration.

[0013] In the compound fertilizer, the slow-release carrier comprises starch and pre-gelatinized starch, and the mass ratio of the starch to the pre-gelatinized starch is (3-5):(2-3).

[0014] In the compound fertilizer, the slow-release regulator microcapsule is a PLGA microcapsule loaded with mannitol and chitin.

[0015] The preparation method of the slow-release regulator microcapsule comprises the following steps: according to the mass ratio of mannitol to chitin=(5-10):(3-8), a regulator is prepared; according to the mass ratio of the regulator to PLGA to ethyl acetate=(1-1.5):(3-4):(10-15), a mixture is prepared; according to the volume ratio of the mixture to polyvinyl alcohol aqueous solution=1:(3-5), the mixture is added to the polyvinyl alcohol aqueous solution with a mass concentration of 1.5-2% under the condition of stirring at 1000-1500r / min, and the stirring reaction is continued for 2-3h to form the microcapsule, centrifugation is carried out at 8000-10000r / min for 15-20min, the precipitate is taken, water washing is carried out for 3-4 times, and vacuum drying is carried out at 30-40°C for 12-16h to obtain the slow-release regulator microcapsule.

[0016] In the compound fertilizer, the nitrogen fertilizer is urea, monoammonium phosphate or diammonium phosphate; the phosphorus fertilizer is monoammonium phosphate or diammonium phosphate; and the potassium fertilizer is potassium chloride, potassium sulfate or potassium nitrate.

[0017] The preparation method of the high-efficiency growth-promoting and regulating type compound fertilizer comprises the following steps:

[0018] S1 core preparation: according to mass fraction, the biological bacteria and biological bacteria protectant are mixed, then the slow-release carrier is added and mixed, water is used to adjust humidity, extrusion granulation is carried out, vacuum drying is carried out, and granulated material is obtained; polyvinylpyrrolidone aqueous solution is sprayed on the surface of the granulated material by a spraying method, vacuum drying is carried out, and core particles are obtained;

[0019] S2 intermediate layer preparation: according to mass fraction, the nitrogen fertilizer, the phosphorus fertilizer, the potassium fertilizer and 15-20 parts of diatomite are uniformly mixed to obtain an intermediate layer material; the core particles are placed in a rotary drum granulator, polyvinyl alcohol aqueous solution is sprayed, and the intermediate layer material is gradually added, granulation is carried out, the intermediate layer material is wrapped around the core particles, vacuum drying is carried out, and large particles are obtained.

[0020] S3 outer layer preparation: according to mass fraction, the slow-release regulator microcapsule and 5-10 parts of diatomite are uniformly mixed to obtain an outer layer material; the large particles are placed in a rotary drum granulator, polyvinyl alcohol aqueous solution is sprayed, and the outer layer material is gradually added, granulation is carried out, the outer layer material is wrapped around the large particles, vacuum drying is carried out, and the compound fertilizer is obtained.

[0021] In S1 of the above preparation method, the water humidity is 30wt%-40wt%; the particle size range of the granulated material is 1mm-2mm; the mass concentration of the polyvinylpyrrolidone aqueous solution is 5%-10%, and the spraying amount of the polyvinylpyrrolidone aqueous solution is 10%-15% of the mass of the granulated material.

[0022] In S2 of the above preparation method, the mass concentration of the polyvinyl alcohol aqueous solution is 3wt%-5wt%, the spraying amount of the polyvinyl alcohol aqueous solution is 8%-12% of the mass of the intermediate layer material, and the rotation speed of the granulation is 50r / min-60r / min.

[0023] In S3 of the above preparation method, the mass concentration of the polyvinyl alcohol aqueous solution is 3wt%-5wt%, the spraying amount of the polyvinyl alcohol aqueous solution is 6%-10% of the mass of the outer layer material, and the rotation speed of the granulation is 40r / min-50r / min.

[0024] In S1, S2 and S3 of the above preparation method, the temperature of the vacuum drying is 30℃-40℃, and the time of the vacuum drying is 2h-4h.

[0025] The above high-efficiency growth-promoting and regulating type compound fertilizer is used for crop base fertilizer.

[0026] The high-efficiency growth-promoting and regulating type compound fertilizer, the preparation method and the application have the following beneficial effects:

[0027] I. The present application designs a special biological bacteria protective agent: chitosan is soaked and swelled with dilute hydrochloric acid, which can make its molecular chain stretch, which is beneficial to subsequent combination with other substances. The base material is prepared by mixing sodium alginate, wet chitosan and pea protein powder in a specific ratio. During enzymolysis, the addition of alginate lyase, chitosanase and papain respectively acts on the corresponding substrate to decompose macromolecular substances into small molecular substances such as sugars and amino acids. These small molecules provide rich nutrients for biological bacteria, which is helpful for the growth and reproduction of biological bacteria. At the same time, the enzymolysis products can also form a protective film around the biological bacteria, enhance the adaptability of the biological bacteria to the environment, improve the stability and activity of the biological bacteria in the compound fertilizer, and make them play a better role.

[0028] II. The slow-release carrier is composed of starch and pregelatinized starch. Starch is gradually decomposed by microorganisms in the soil, and pregelatinized starch has good water solubility and adhesion, which can synergistically act with starch. After mixing them in a certain proportion, a slowly degradable structure is formed in the soil. When the compound fertilizer is applied to the soil, the nutrients in the slow-release carrier are gradually released, prolonging the fertilizer effect, so that crops can continuously absorb nutrients for a long time, avoiding the rapid loss of nutrients, and improving the utilization rate of fertilizer.

[0029] III. The slow-release regulator microcapsule is prepared by mixing mannitol and chitin in a certain proportion, which can synergistically promote the growth of crops, improve the stress resistance, and adjust the soil structure. PLGA is a biodegradable polymer material with good film-forming and slow-release properties. In the stirring state, the mixture is added to the polyvinyl alcohol aqueous solution to form microcapsules. Polyvinyl alcohol plays a role in emulsifying and stabilizing microcapsules; it can wrap the regulator inside to protect it from the external environment, and avoid the influence on biological bacteria in the early stage. During the growth of crops, the microcapsules will slowly release the regulator with the change of time and environmental conditions, which can well promote the growth of crops, improve the stress resistance and quality of crops.

[0030] IV. Core preparation: biological bacteria and biological bacteria protective agent are thoroughly mixed to make the biological bacteria uniformly dispersed in the protective agent, which can protect the biological bacteria from the influence of the external environment. After adding the slow-release carrier, adjust the humidity with water for extrusion granulation, which can make the biological bacteria, protective agent and slow-release carrier form a close whole. Vacuum drying at 35℃ helps to remove water, while avoiding the influence of high temperature on the activity of biological bacteria. Spray polyvinylpyrrolidone solution on the surface of the granulated material, which can form a uniform protective film on the surface of the granulated material, further improving the ability of biological bacteria to resist high temperature, high salt and other adverse environments during the production process of compound fertilizer, and the stability during storage, thereby improving the survival rate of biological bacteria.

[0031] Five, intermediate layer preparation: mix nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and diatomite uniformly to obtain an intermediate layer material. Diatomite has a large specific surface area and good adsorption performance, and can adsorb a large amount of nitrogen, phosphorus and potassium nutrients. Place the core particles in a drum granulator, spray polyvinyl alcohol aqueous solution and add the intermediate layer material for granulation. Polyvinyl alcohol acts as a binder, which can firmly wrap the intermediate layer material on the surface of the core particles to form an intermediate coating layer. Such an intermediate layer structure not only can store a large amount of nutrients, but also can slowly release nutrients due to the adsorption and slow-release effect of diatomite and the wrapping of the intermediate layer, thereby meeting the needs of crops at different growth stages for a large amount of nutrients and reducing nutrient loss.

[0032] Six, outer layer preparation: mix the slow-release regulator microcapsules with diatomite to obtain an outer layer material, and then place the large particles in a drum granulator, spray polyvinyl alcohol aqueous solution and add the outer layer material for granulation to wrap the large particles with the outer layer material. The structure formed by diatomite and polyvinyl alcohol in the outer layer can protect the slow-release regulator microcapsules from premature release or damage in the external environment. During crop growth, as the compound fertilizer gradually decomposes in the soil and water penetrates, the outer layer structure will gradually degrade, thereby controlling the slow release of the regulator in the slow-release regulator microcapsules and enabling the regulator to play a role in the critical period of crop growth, further promoting crop growth and improving crop quality and stress resistance.

[0033] Seven, the three-layer structure design of the compound fertilizer of the present application reasonably separates the biological bacteria, nutrients and slow-release regulator microcapsules, so that the compound fertilizer can not only protect the activity of the biological bacteria, but also provide sustained nutrient supply and accurately regulate crop growth, thereby achieving the dual effects of efficient growth promotion and soil improvement.

[0034] In summary, the efficient growth-promoting and regulating type compound fertilizer of the present application innovatively adds biological bacteria and protective agent core particles, combines the intermediate layer of nitrogen, phosphorus and potassium fertilizers, and the outer layer of slow-release regulator microcapsules to achieve the effects of nutrient supply, plant growth regulation and soil improvement. The preparation process uses a special granulation process to ensure the uniformity and stability of the fertilizer particles, and at the same time enables the beneficial microbial flora to maintain activity in the fertilizer. The compound fertilizer of the present application is suitable for various types of soil and crops, and has remarkable effects in promoting crop growth, improving photosynthetic efficiency, increasing crop yield, improving agricultural product quality and soil improvement, thereby providing strong support for sustainable agricultural development. DETAILED DESCRIPTION

[0035] The present application will be further described below in conjunction with specific implementation examples, but the present application is not limited to these examples.

[0036] Example 1

[0037] The application discloses a high-efficiency growth-promoting and regulation type compound fertilizer, which comprises the following raw materials in mass parts: 0.3 parts of biological bacteria, 0.5 parts of biological bacteria protective agent, 0.8 parts of slow-release carrier, 23 parts of nitrogen fertilizer, 17 parts of phosphorus fertilizer, 12 parts of potassium fertilizer, 0.2 parts of slow-release regulator microcapsule and 25 parts of diatomite; the compound fertilizer is divided into three layers, the core is a core particle which is coated by polyvinylpyrrolidone and is granulated by starch and pregelatinized starch after mixing the biological bacteria protective agent and the biological bacteria, the middle layer is a middle coating layer which is bonded by polyvinyl alcohol and is prepared by mixing diatomite, nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer, and the outer layer is an outer coating layer which is bonded by polyvinyl alcohol and is prepared by mixing diatomite, slow-release regulator microcapsule and the slow-release carrier.

[0038] The biological bacteria comprise bacillus subtilis, bacillus megaterium and nitrogen-fixing bacteria, and the mass ratio of the bacillus subtilis, the bacillus megaterium and the nitrogen-fixing bacteria is bacillus subtilis: bacillus megaterium: nitrogen-fixing bacteria = 35:30:25.

[0039] The preparation method of the biological bacteria protective agent comprises the following steps: the chitosan is soaked in 0.2 mol / L dilute hydrochloric acid solution for 2.5 h, is washed with deionized water until neutral, is extracted and filtered to obtain wet chitosan; base materials are prepared according to the mass ratio of sodium alginate:wet chitosan:pea protein powder = 2.5:4:6.5, 11 times the mass of water is added to the base materials, 0.8% of the mass of sodium alginate of alginate lyase is added, 1.2% of the mass of wet chitosan of chitosanase is added, 1.5% of the mass of soybean protein of papain is added, enzymolysis is carried out at 45 DEG C for 4 h, the enzyme is inactivated at 95 DEG C for 15 min, concentration and drying are carried out to obtain the biological bacteria protective agent.

[0040] The slow-release carrier comprises starch and pregelatinized starch, and the mass ratio of the starch and the pregelatinized starch is starch: pregelatinized starch = 4:2.5.

[0041] The slow-release regulator microcapsule is a PLGA microcapsule loaded with mannitol and chitin. The preparation method of the slow-release regulator microcapsule comprises the following steps: adjusting agent is prepared according to the mass ratio of mannitol: chitin = 8:5; a mixture is prepared according to the mass ratio of adjusting agent: PLGA: ethyl acetate = 1.2:3.5:13; the mixture is added into polyvinyl alcohol aqueous solution with a mass concentration of 1.8% under the condition of stirring at 1200 r / min according to the volume ratio of the mixture: polyvinyl alcohol aqueous solution = 1:4, the stirring reaction is continued for 2.5 h to form the microcapsule, centrifugation is carried out at 9000 r / min for 18 min, the precipitate is taken, water washing is carried out for three times, and vacuum drying is carried out at 35 DEG C for 15 h to obtain the slow-release regulator microcapsule.

[0042] The nitrogen fertilizer is urea; the phosphorus fertilizer is monopotassium phosphate; and the potassium fertilizer is potassium chloride.

[0043] The preparation method of the above-mentioned high-efficiency growth-promoting and regulation type compound fertilizer comprises the following steps:

[0044] S1 core preparation: by mass fraction, the biological bacteria and biological bacteria protectant are mixed thoroughly, then the slow-release carrier is added and mixed, the humidity is adjusted to 35wt% with water, extrusion granulation, 4h vacuum drying at 35℃, to get granulated material with particle size range of 1mm-2mm; the polyvinylpyrrolidone aqueous solution with mass concentration of 8% is sprayed on the surface of the granulated material by spraying method, the spraying amount is 12% of the mass of the granulated material, 2.5h vacuum drying at 35℃, to get core particles;

[0045] S2 intermediate layer preparation: by mass fraction, the nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and 18 parts of diatomite are mixed uniformly to get the intermediate layer material; the core particles are placed in the drum granulator, the intermediate layer material is sprayed at a spraying amount of 10% of the mass of the intermediate layer material, the polyvinyl alcohol aqueous solution with mass concentration of 4wt% is sprayed at the same time, and the intermediate layer material is gradually added, the granulation is carried out at a rotating speed of 55r / min, so that the intermediate layer material wraps the core particles, 2.5h vacuum drying at 35℃, to get large particles;

[0046] S3 outer layer preparation: by mass fraction, the slow-release regulator microcapsule and 7 parts of diatomite are mixed uniformly to get the outer layer material, the large particles are placed in the drum granulator, the outer layer material is sprayed at a spraying amount of 8% of the mass of the outer layer material, the polyvinyl alcohol aqueous solution with mass concentration of 4wt% is sprayed at the same time, and the outer layer material is gradually added, the granulation is carried out at a rotating speed of 45r / min, so that the outer layer material wraps the large particles, 2h vacuum drying at 35℃, to get the compound fertilizer.

[0047] The above-mentioned high-efficiency growth-promoting and regulating type compound fertilizer is used as base fertilizer for crops.

[0048] Example 2

[0049] A high-efficiency growth-promoting and regulating type compound fertilizer, the compound fertilizer comprises the following raw materials by mass fraction: biological bacteria 0.1 part, biological bacteria protectant 0.3 part, slow-release carrier 0.5 part, nitrogen fertilizer 20 parts, phosphorus fertilizer 15 parts, potassium fertilizer 10 parts, slow-release regulator microcapsule 0.15 part, diatomite 20 parts; the compound fertilizer has a three-layer structure, the core is the core particles coated by polyvinylpyrrolidone after the biological bacteria protectant is mixed with the biological bacteria and then granulated by starch and pregelatinized starch, the intermediate layer is the intermediate coating layer bonded by polyvinyl alcohol after the diatomite is mixed with the nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer, and the outer layer is the outer coating layer bonded by polyvinyl alcohol after the diatomite is mixed with the slow-release regulator microcapsule.

[0050] The biological bacteria comprise bacillus subtilis, bacillus megaterium and nitrogen-fixing bacteria, and the mass ratio of bacillus subtilis: bacillus megaterium: nitrogen-fixing bacteria is 30:25:20.

[0051] The preparation method of the biological bacteria protective agent comprises the following steps: the chitosan is soaked in 0.1 mol / L dilute hydrochloric acid solution for 2 h, and then washed with deionized water until neutral; the wet chitosan is obtained by filtration; the base material is prepared according to the mass ratio of sodium alginate:wet chitosan:pea protein powder = 2:3:5; 10 times the mass of water is added to the base material; 0.5% of the mass of sodium alginate is added to the alginate lyase; 1% of the mass of wet chitosan is added to the chitosanase; 1% of the mass of soybean protein is added to the papain; the enzymolysis is carried out at 40°C for 3 h; the enzyme is inactivated at 90°C for 10 min; the concentrated and dried biological bacteria protective agent is obtained.

[0052] The slow-release carrier comprises starch and pre-gelatinized starch, and the mass ratio of the starch to the pre-gelatinized starch is 3:2.

[0053] The slow-release regulator microcapsule is a PLGA microcapsule loaded with mannitol and chitin. The preparation method of the slow-release regulator microcapsule comprises the following steps: the regulator is prepared according to the mass ratio of mannitol to chitin = 5:3; the mixture is prepared according to the mass ratio of the regulator to PLGA to ethyl acetate = 1:3:10; the mixture is added to the polyvinyl alcohol aqueous solution with a mass concentration of 1.5% under the condition of stirring at 1000 r / min; the microcapsule is formed by continuing to stir for 2 h; the microcapsule is obtained by centrifuging at 8000 r / min for 15 min, washing with water for 3 times, and vacuum drying at 30°C for 12 h.

[0054] The nitrogen fertilizer is monopotassium phosphate; the phosphorus fertilizer is diammonium phosphate; and the potassium fertilizer is potassium sulfate.

[0055] The preparation method of the above-mentioned high-efficiency growth-promoting and regulating type compound fertilizer comprises the following steps:

[0056] S1, the core preparation: the biological bacteria and the biological bacteria protective agent are mixed, and then the slow-release carrier is added and mixed; the humidity is adjusted to 30 wt% by adding water; the granulation is carried out by extrusion; the granulation material with a particle size range of 1 mm to 2 mm is obtained by vacuum drying at 30°C for 3 h; the polyvinylpyrrolidone aqueous solution with a mass concentration of 5% is sprayed on the surface of the granulation material by a spraying method; the spraying amount is 10% of the mass of the granulation material; and the core granule is obtained by vacuum drying at 30°C for 2 h.

[0057] S2, the intermediate layer preparation: the nitrogen fertilizer, the phosphorus fertilizer, the potassium fertilizer, and 15 parts of diatomite are uniformly mixed to obtain the intermediate layer material; the core granule is placed in a rotary drum granulator; the intermediate layer material is sprayed at a spraying amount of 8% of the mass of the intermediate layer material; the polyvinyl alcohol aqueous solution with a mass concentration of 3 wt% is sprayed; and the intermediate layer material is gradually added; the intermediate layer material is wrapped around the core granule by granulating at a rotating speed of 50 r / min; and the large granule is obtained by vacuum drying at 30°C for 2 h.

[0058] S3 outer layer preparation: by mass fraction, the slow-release regulator microcapsule is mixed with 5 parts of diatomite to obtain an outer layer material. The large particles are placed in a rotary drum granulator, and 6% of the outer layer material is sprayed at a mass concentration of 3wt% polyvinyl alcohol solution. At the same time, the outer layer material is gradually added, and the granulation is carried out at a speed of 40r / min, so that the outer layer material wraps the large particles. After vacuum drying at 30℃ for 1h, the compound fertilizer is obtained.

[0059] The above-mentioned high-efficiency growth-promoting and regulating type compound fertilizer is used as base fertilizer for crops.

[0060] Example 3

[0061] A high-efficiency growth-promoting and regulating type compound fertilizer, which comprises the following raw materials by mass fraction: biological bacteria 0.5 parts, biological bacteria protective agent 0.8 parts, slow-release carrier 1 part, nitrogen fertilizer 25 parts, phosphorus fertilizer 20 parts, potassium fertilizer 15 parts, slow-release regulator microcapsule 0.25 parts, diatomite 30 parts. The compound fertilizer has a three-layer structure, the core is a core particle coated by polyvinylpyrrolidone, which is prepared by granulating biological bacteria mixed with biological bacteria protective agent by starch and pregelatinized starch; the middle layer is a middle coating layer bonded by polyvinyl alcohol, which is prepared by mixing diatomite, nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer; and the outer layer is an outer coating layer bonded by polyvinyl alcohol, which is prepared by mixing diatomite and slow-release regulator microcapsule.

[0062] The biological bacteria comprise Bacillus subtilis, Bacillus megaterium and nitrogen-fixing bacteria, and the mass ratio of Bacillus subtilis, Bacillus megaterium and nitrogen-fixing bacteria is 40:35:30.

[0063] The preparation method of the biological bacteria protective agent comprises the following steps: chitosan is soaked in 0.3mol / L dilute hydrochloric acid solution for 3h, and then washed with deionized water until neutral. After suction filtration, wet chitosan is obtained. A base material is prepared according to a mass ratio of sodium alginate:wet chitosan:pea protein powder = 3:5:8. Water with a mass of 12 times the mass of the base material is added, and 1% of the mass of sodium alginate is added to the sea algin acid lyase, 1.5% of the mass of wet chitosan is added to the chitosanase, and 2% of the mass of soybean protein is added to the papain. Enzymolysis is carried out at 50℃ for 5h, and the enzyme is inactivated at 100℃ for 20min. After concentration and drying, the biological bacteria protective agent is obtained.

[0064] The slow-release carrier comprises starch and pregelatinized starch, and the mass ratio of starch and pregelatinized starch is 5:3.

[0065] The slow-release regulator microcapsule is a PLGA microcapsule loaded with mannitol and chitin. The preparation method of the slow-release regulator microcapsule comprises the following steps: preparing a regulator according to a mass ratio of mannitol: chitin = 10:8; preparing a mixture according to a mass ratio of regulator: PLGA: ethyl acetate = 1.5:4:15; mixing the mixture with a polyvinyl alcohol aqueous solution according to a volume ratio of 1:5; under the condition of stirring at 1500 r / min, adding the mixture into the polyvinyl alcohol aqueous solution with a mass concentration of 2%; continuing to stir for 3 h to form the microcapsule; centrifuging at 10000 r / min for 20 min; taking the precipitate; washing with water for 4 times; and vacuum drying at 40℃ for 16 h to obtain the slow-release regulator microcapsule.

[0066] The nitrogen fertilizer is diammonium phosphate; the phosphorus fertilizer is monoammonium phosphate; and the potassium fertilizer is potassium nitrate.

[0067] The preparation method of the above high-efficiency growth-promoting regulator type compound fertilizer comprises the following steps:

[0068] S1 core preparation: mixing biological bacteria and biological bacteria protectant according to mass parts, then mixing with a slow-release carrier, adjusting humidity to 40wt% with water, extruding and granulating, and vacuum drying at 40℃ for 5 h to obtain granulated materials with a particle size range of 1mm-2mm; spraying a polyvinylpyrrolidone aqueous solution with a mass concentration of 10% on the surface of the granulated materials by a spraying method, the spraying amount being 15% of the mass of the granulated materials, and vacuum drying at 40℃ for 3 h to obtain core particles;

[0069] S2 intermediate layer preparation: uniformly mixing nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and 20 parts of diatomite to obtain an intermediate layer material; placing the core particles in a rotary drum granulator, spraying a polyvinyl alcohol aqueous solution with a mass concentration of 5wt% at a spraying amount of 12% of the mass of the intermediate layer material, and gradually adding the intermediate layer material at a rotating speed of 60 r / min to granulate the intermediate layer material to wrap the core particles, and vacuum drying at 40℃ for 3 h to obtain large particles;

[0070] S3 outer layer preparation: uniformly mixing slow-release regulator microcapsules and 10 parts of diatomite to obtain an outer layer material, placing the large particles in a rotary drum granulator, spraying a polyvinyl alcohol aqueous solution with a mass concentration of 5wt% at a spraying amount of 10% of the mass of the outer layer material, and gradually adding the outer layer material at a rotating speed of 50 r / min to granulate the outer layer material to wrap the large particles, and vacuum drying at 40℃ for 3 h to obtain the compound fertilizer.

[0071] The above high-efficiency growth-promoting regulator type compound fertilizer is used for crop base fertilization.

[0072] In the above embodiments, Bacillus subtilis is from Shandong Xizhuoyuan Biotechnology Co., Ltd., with a bacterial activity of 20 billion CFU / g. Bacillus megaterium is from Jin Yuyuan Biotechnology Co., Ltd., with a bacterial activity of 10 billion CFU / g. Azotobacter is from Shanghai Ruichu Biotechnology Co., Ltd., which is Azotobacter chroococcum. Chitosan is from Xi'an Aosai Biotechnology Co., Ltd. Sodium alginate is from Fujian Zhongjiamisheng Biotechnology Co., Ltd. Pea protein powder is from Shanghai Yugui Trading Co., Ltd., with a product number of 00242. Alginate lyase is from Shanxi Zhongnuo Biotechnology Co., Ltd., with an enzyme activity of 100,000 U / g. Chitosanase is from Nanjing Xinqiehui Biotechnology Co., Ltd., with an enzyme activity of 100,000 U / g. Papain is from Henan Anrui Biotechnology Co., Ltd., with an enzyme activity of 100,000 U / g. Starch is from Henan Fengwei Biotechnology Co., Ltd., which is corn starch. Pre-gelatinized starch is from Anhui Weimo Biotechnology Co., Ltd. Mannitol is from Guangdong Aosiman Biotechnology Co., Ltd., which is D-mannitol. Chitin is from Shaanxi Zelang Biotechnology Co., Ltd., which is extracted from shrimp and crab shells. PLGA is polylactic acid-glycolic acid copolymer, which is from Henan Wokes Biotechnology Co., Ltd. Ethyl acetate is from Zibo Notai Chemical Co., Ltd. Polyvinylpyrrolidone is from Jinbang Environmental Protection Technology Co., Ltd., which is PVP K30. Polyvinyl alcohol is from Shandong Tengxiao New Material Co., Ltd., with a model number of 088-50.

[0073] Comparative Example 1

[0074] In the compound fertilizer, the biological bacteria protective agent is replaced by starch; other parameters and methods are the same as in Example 1.

[0075] Comparative Example 2

[0076] In the preparation method of the biological bacteria protective agent, wet chitosan and pea protein powder are both replaced by sodium alginate, and chitosanase and papain are not added; other parameters and methods are the same as in Example 1.

[0077] Comparative Example 3

[0078] In the preparation method of the biological bacteria protective agent, sodium alginate and pea protein powder are both replaced by wet chitosan, and alginate lyase and papain are not added; other parameters and methods are the same as in Example 1.

[0079] Comparative Example 4

[0080] In the preparation method of the biological bacteria protective agent, sodium alginate and wet chitosan are both replaced by wet chitosan, and alginate lyase and chitosanase are not added; other parameters and methods are the same as in Example 1.

[0081] Comparative Example 5

[0082] The slow-release regulator microcapsule directly replaces the regulator component without preparing the microcapsule; the other parameters and methods are the same as in Example 1.

[0083] Comparative Example 6

[0084] The compound fertilizer is not prepared in a three-layer structure, and the raw materials are directly blended to obtain the compound fertilizer; the other parameters and methods are the same as in Example 1.

[0085] Comparative Example 7

[0086] Steps S2 and S3 are reversed to prepare; that is, the outer layer becomes the middle layer, and the middle layer becomes the outer layer; the other parameters and methods are the same as in Example 1.

[0087] The above-mentioned compound fertilizers are subjected to fertilization planting effect detection.

[0088] 1. Experimental crop selection:

[0089] The cucumber variety "Jinyou No. 2" which is common and sensitive to fertilizer nutrients is selected. The cucumber has a relatively short growth cycle, obvious growth characteristics, and a clear response to fertilizer, which facilitates the acquisition of experimental data within a limited time.

[0090] 2. Experimental grouping:

[0091] Three example groups (Examples 1, 2, and 3) and seven comparative example groups (Comparative Examples 1-7) are set up.

[0092] Each group is arranged with 5 repetitions, and 20 cucumber seedlings are planted in each experimental plot with an area of 1 square meter.

[0093] 3. Soil preparation:

[0094] Sand loam soil is selected, which has uniform texture, moderate air permeability and water retention, and is a common soil type suitable for cucumber growth. Before the experiment, the soil is comprehensively detected to ensure that the basic fertility of the soil is consistent. After the soil is mixed uniformly, the soil is replaced at the corresponding position of the experimental plot to ensure that the soil environment for the growth of each cucumber is basically the same.

[0095] 4. Fertilization treatment:

[0096] When the cucumbers are planted, 100 g of compound fertilizer is applied as base fertilizer for each plant in a uniform spreading manner. After fertilization, shallow plowing is performed to mix the fertilizer and soil thoroughly, ensuring that the fertilizer can uniformly provide nutrients for the cucumber root system. Normal watering is performed during the growth period.

[0097] 5. Growth index determination:

[0098] Plant height: measured at 9:00-11:00 am on the 60th day of cucumber growth. The 20 cucumbers in each repetition are all measured, and the average value is finally calculated.

[0099] Leaf number: Statistics were made at the same time points as described above, with fully expanded leaves as the criterion, the number of leaves per cucumber plant was counted, and the average value was calculated after statistics of 20 cucumber plants per repeat.

[0100] Fruit yield: After the cucumber entered the harvest period, the weight of all fruits in each repeat was recorded at each time of harvesting, until the end of the harvest period. The fruit weight of each harvest was added up to calculate the total fruit yield of each repeat, and finally the average value was calculated.

[0101] Fruit quality: 10 fruits were randomly selected during the harvest period, and the vitamin C content (mg / 100g) was determined by 2,6-dichloroindophenol titration method, and the average value was taken. Similarly, 10 fruits were randomly selected during the harvest period, and the soluble sugar content was determined by anthrone colorimetry at 620 nm wavelength, and the average value was taken.

[0102] Soil microbial quantity: On the 60th day of cucumber growth, 5 soil samples from different positions were selected in each repeat, and these samples were thoroughly mixed to serve as the soil sample of the repeat. The dilution plate method was used to determine the number of bacteria, fungi and actinomycetes in the soil (individuals / g dry soil). The soil sample was gradient diluted, and the appropriate dilution of soil suspension was coated on beef extract peptone medium (for culturing bacteria), Martin's medium (for culturing fungi), and Gao's No. 1 medium (for culturing actinomycetes). After incubation at an appropriate temperature for a certain period of time, the number of colonies on the plate was counted, and the number of microorganisms in the soil was calculated according to the dilution factor.

[0103] Alkaline phosphatase activity: Determined by phosphoric acid benzene disodium colorimetry. Take 5g of air-dried soil sample, add 50mL, pH8.0 Tris-hydrochloric acid buffer and 5mL 0.025mol / L phosphoric acid benzene disodium solution, incubate at 37℃ constant temperature for 24 hours, after the reaction is completed, add chromogenic agent, measure the absorbance at 660nm wavelength on the spectrophotometer, and calculate the alkaline phosphatase activity (mg phenol / g soil·24h).

[0104] Table 1 detection data results

[0105]

[0106]

[0107] From the above results, the compound fertilizers of Examples 1 to 3 have good crop growth regulation effect, the biological bacteria protective agent and the slow-release carrier can well protect and maintain the activity of the bacteria, and promote the role of biological bacteria. The release of the regulator by microcapsules can well play the regulation effect at the appropriate time. The three-layer structure can regulate the action time of each component, play a good fertilizer effect at the appropriate growth stage, promote crop growth, increase fruit yield, and improve the nutritional value of fruits. In addition, it can also well regulate the soil environment.

[0108] In Comparative Example 1, starch is used as a substitute for the biological bacteria protective agent, and its chemical structure and properties are quite different from those of the specially prepared biological bacteria protective agent. Starch cannot provide the nutrients and protection required for biological bacteria to survive in the complex environment of the soil, resulting in biological bacteria being more susceptible to inactivation by high salinity, changes in pH, and other adverse factors in the soil. The reduction in the number of biological bacteria disrupts the structure and function of the beneficial microbial community in the soil. The mutual cooperation between bacteria, fungi, and actinomycetes and other microorganisms in the soil is broken, the soil microbial ecosystem is imbalanced, and the transformation and cycling of nutrients in the soil are affected. The availability of nutrients in the soil decreases, and the roots of crops cannot absorb enough nutrients, affecting the normal growth and development of crops. This is manifested as lower plant height, fewer leaf numbers, lower fruit yield, and poor fruit quality. The activity of soil enzymes also decreases due to the reduction in the number of microorganisms, further affecting soil fertility.

[0109] In Comparative Example 2, wet chitosan and pea protein powder are both replaced by sodium alginate, and no chitosanase and papain are added, making the composition of the biological bacteria protective agent single. Although sodium alginate has a certain protective effect, it lacks the small molecular chitooligosaccharides produced by the action of chitosanase on wet chitosan and the amino acids produced by the action of papain on pea protein powder. A single sodium alginate cannot form a comprehensive and effective protection system for biological bacteria, and the survival and reproduction of biological bacteria in the soil are limited. Although the number of microorganisms in the soil decreases, compared with Comparative Example 1, the decline in various indicators is relatively small due to the protective effect of sodium alginate.

[0110] In Comparative Example 3, sodium alginate and pea protein powder are replaced by wet chitosan, and no alginate lyase and papain are added, making the structure and composition of the biological bacteria protective agent unreasonable. Wet chitosan cannot provide the functions of sodium alginate enzyme products, such as hydrophilicity and affinity for biological bacteria, nor can it provide the nutrients produced by the enzymatic hydrolysis of pea protein powder. The activity of biological bacteria decreases under this protective agent, the structure of the soil microbial community changes, and the ability of microorganisms to decompose organic matter and transform nutrients in the soil decreases, leading to a decrease in soil enzyme activity and affecting crop growth. The indicators are lower than those of Example 1.

[0111] In Comparative Example 4, sodium alginate and wet chitosan are both replaced by wet chitosan, and no alginate lyase and chitosanase are added, so that the key enzymolysis products are lacking in the bio-bacterial protective agent. These enzymolysis products play an important role in the protection, nutrition supply, and colonization and reproduction of bio-bacteria in the soil, and the lack of them makes the survival of bio-bacteria in the soil worse. The bio-bacterial activity and quantity decrease seriously, the balance of the soil ecosystem is broken, the soil fertility is reduced, the crop roots cannot obtain sufficient nutrients and the support of beneficial microorganisms, leading to poor growth and development of crops, and all test indexes are lower than those in Example 1.

[0112] In Comparative Example 5, no slow-release regulator microcapsules are prepared, and the regulator ingredients are directly applied to the soil. Since the regulator is easily subjected to photolysis, hydrolysis, and microbial decomposition in the soil, it will quickly be lost or lose activity, and cannot continuously and stably provide regulation for crop growth. The crops lack sustained and effective hormone regulation during growth, and although the bio-bacteria and nutrients in the fertilizer can ensure certain growth, the fruit quality and yield are poorer than those in Example 1.

[0113] In Comparative Example 6, the compound fertilizer is not prepared in a three-layer structure, and the raw materials are directly blended. The bio-bacteria directly contact the chemical fertilizer, and the high salinity and chemical properties in the production process of the chemical fertilizer cause damage to the bio-bacteria, leading to a decrease in bio-bacterial activity. The regulator cannot be effectively released, and the nutrient supply in the soil cannot be reasonably distributed according to the growth needs of crops, resulting in waste and environmental pollution due to excessive nutrients in the early stage, and insufficient nutrients affecting crop growth in the later stage. The number of soil microorganisms and enzyme activity are lower than those in Example 1, and the crop growth indexes are not as good as those in Example 1.

[0114] In Comparative Example 7, steps S2 and S3 are reversed to prepare, and the slow-release regulator microcapsules and diatomite in the outer layer are first wrapped around the core particles, and the chemical fertilizer in the middle layer is then wrapped. In this way, at the initial stage of preparation and fertilization, the chemical fertilizer directly contacts the bio-bacteria, causing damage to the bio-bacteria during the preparation process or in the soil in the early stage, affecting the activity and quantity thereof; the slow-release regulator microcapsules cannot effectively play a regulating role in the outermost layer, and the effect on crop growth and fruit quality improvement is not as good as that in Example 1.

Claims

1. A high-efficiency growth-promoting and regulating compound fertilizer, characterized in that, The compound fertilizer comprises the following raw materials in parts by weight: 0.1-0.5 parts of biological bacteria, 0.3-0.8 parts of biological bacteria protectant, 0.5-1 part of slow-release carrier, 20-25 parts of nitrogen fertilizer, 15-20 parts of phosphorus fertilizer, 10-15 parts of potassium fertilizer, 0.15-0.25 parts of slow-release regulator microcapsules, and 20-30 parts of diatomaceous earth. The compound fertilizer has a three-layer structure: the core is a core granule made of biological bacteria protectant mixed with biological bacteria, granulated from starch and pregelatinized starch, and then coated with polyvinylpyrrolidone; the middle layer is an intermediate coating layer made of diatomaceous earth mixed with nitrogen, phosphorus, and potassium fertilizers and bonded with polyvinyl alcohol; the outer layer is an outer coating layer made of diatomaceous earth mixed with slow-release regulator microcapsules and bonded with polyvinyl alcohol. The biological protective agent is a base material prepared by enzymatic hydrolysis of sodium alginate, wet chitosan and pea protein powder in a mass ratio of (2-3):(3-5):(5-8) by alginate lyase, chitosanase and papain. The wet chitosan is obtained by soaking chitosan in 0.1mol / L-0.3mol / L dilute hydrochloric acid solution for 2-3 hours to fully swell, then washing with deionized water until neutral, and filtering to obtain wet chitosan. The sustained-release carrier comprises starch and pregelatinized starch in a mass ratio of (3-5):(2-3); The sustained-release regulator microcapsules are PLGA microcapsules loaded with mannitol and chitosan.

2. The high-efficiency growth-promoting and regulating compound fertilizer according to claim 1, characterized in that, The microorganisms include Bacillus subtilis: Bacillus megaterium: nitrogen-fixing bacteria in a mass ratio of (30-40): (25-35): (20-30).

3. The high-efficiency growth-promoting and regulating compound fertilizer according to claim 1, characterized in that, The preparation method of the biological microbial protectant includes the following steps: Prepare a base material by mixing sodium alginate, wet chitosan, and pea protein powder in a mass ratio of (2-3):(3-5):(5-8). Add water at 10-12 times the mass of the base material, add 0.5%-1% alginate lyase (by mass of sodium alginate), add 1%-1.5% chitosanase (by mass of wet chitosan), and add 1%-2% papain (by mass of soybean protein). Perform enzymatic hydrolysis at 40-50℃ for 3-5 hours, inactivate the enzyme at 90-100℃ for 10-20 minutes, concentrate, and dry to obtain the biological microbial protectant.

4. The high-efficiency growth-promoting and regulating compound fertilizer according to claim 1, characterized in that, The preparation method of sustained-release regulator microcapsules includes the following steps: Prepare regulator by mass ratio of mannitol:chitosan = (5-10):(3-8); prepare mixture by mass ratio of regulator:PLGA:ethyl acetate = (1-1.5):(3-4):(10-15); prepare mixture by volume ratio of mixture:polyvinyl alcohol aqueous solution = 1:(3-5), adding the mixture to a 1.5%-2% polyvinyl alcohol aqueous solution under stirring at 1000-1500 r / min, continuing stirring for 2-3 hours to form microcapsules, centrifuging at 8000-10000 r / min for 15-20 minutes, collecting the precipitate, washing with water 3-4 times, and vacuum drying at 30-40℃ for 12-16 hours to obtain sustained-release regulator microcapsules.

5. The high-efficiency growth-promoting and regulating compound fertilizer according to claim 1, characterized in that, Nitrogen fertilizers include urea, monoammonium phosphate, or diammonium phosphate; phosphate fertilizers include monoammonium phosphate or diammonium phosphate; and potassium fertilizers include potassium chloride, potassium sulfate, or potassium nitrate.

6. The preparation method of a high-efficiency growth-promoting and regulating compound fertilizer according to claim 1, characterized in that, Includes the following steps: S1 Core Preparation: The microorganisms and microbial protectant were thoroughly mixed according to the mass ratio, and then a slow-release carrier was added and mixed. The humidity was adjusted with water, and the mixture was extruded and granulated. The granules were then vacuum dried to obtain the granulated material. Polyvinylpyrrolidone aqueous solution was sprayed onto the surface of the granulated material using a spray method and then vacuum dried to obtain the core particles. S2 Intermediate Layer Preparation: Nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and 15 to 20 parts of diatomaceous earth are mixed evenly according to the mass ratio to obtain the intermediate material; the core particles are placed in a rotary drum granulator, polyvinyl alcohol aqueous solution is sprayed in, and the intermediate material is gradually added at the same time to granulate, so that the intermediate material coats the core particles, and vacuum drying is performed to obtain large particles. S3 outer layer preparation: Mix the slow-release regulator microcapsules with 5 to 10 parts of diatomaceous earth according to the mass ratio to obtain the outer layer material. Place the large particles in a rotary drum granulator, spray in a polyvinyl alcohol aqueous solution, and gradually add the outer layer material at the same time to granulate, so that the outer layer material coats the large particles. Vacuum dry to obtain compound fertilizer.

7. The method for preparing a high-efficiency growth-promoting and regulating compound fertilizer according to claim 6, characterized in that, In S1, the water content for humidity adjustment is 30wt%–40wt%; the particle size range of the granulated material is 1mm–2mm; the mass concentration of the polyvinylpyrrolidone aqueous solution is 5%–10%, and the spraying amount of the polyvinylpyrrolidone aqueous solution is 10%–15% of the mass of the granulated material. In S2, the mass concentration of the polyvinyl alcohol aqueous solution is 3wt% to 5wt%, and the amount of polyvinyl alcohol aqueous solution injected is 8% to 12% of the mass of the interlayer material; the granulation speed is 50 r / min to 60 r / min. In S3, the mass concentration of the polyvinyl alcohol aqueous solution is 3wt% to 5wt%, and the amount of polyvinyl alcohol aqueous solution injected is 6% to 10% of the mass of the outer layer material; the granulation speed is 40 r / min to 50 r / min. In S1, S2 and S3, the vacuum drying temperature is 30℃~40℃ and the vacuum drying time is 2h~4h.

8. The high-efficiency growth-promoting and regulating compound fertilizer as described in claim 1 is used as a base fertilizer for crops.

Images