Preparation method of functional medium trace element fertilizer

Abstract

The invention belongs to the technical field of fertilizer preparation, particularly relates to a preparation method of a functional medium trace element fertilizer, and aims to solve the problems that in the existing fertilizer preparation process, a coating layer usually only pays attention to physical slow release and lacks the function of synergistically providing active substances (such as amino acid and polysaccharide) and trace elements; in order to solve the problem that the conventional addition mode of trace elements is difficult to ensure the stability and bioavailability of the feed, the invention provides the following scheme: the preparation method comprises the following steps: S1, preparing materials: 15-30 parts of straws, 5-15 parts of soybean meal and 3-10 parts of molasses; through use of the straw, the soybean meal, the molasses, the bacillus subtilis, the nitrogen-fixing bacteria, the phosphate solubilizing bacteria, the trichoderma, the nitrogen-phosphorus-potassium fertilizer, the humic acid, the ferrous sulfate, the zinc sulfate, the manganese sulfate, the boric acid, the sodium molybdate, the sodium alginate, the chitosan and the serine, the problems of single coating function, poor trace element stability and low bioavailability in the fertilizer preparation process are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fertilizer preparation, in particular to a preparation method of functional medium and trace element fertilizer. BACKGROUND

[0002] Biofertilizer is a fertilizer containing specific types and amounts of beneficial microorganisms and nutrients. Its core function is to improve the soil environment and promote plant growth through the life activities of beneficial microorganisms.

[0003] In the prior art, during the preparation of the fertilizer, the coating layer often only focuses on physical slow release, lacks the function of synergistically providing active substances (such as amino acids and polysaccharides) and trace elements, and the conventional addition method of trace elements is difficult to ensure the stability and bioavailability thereof. Therefore, the present application provides a preparation method of functional medium and trace element fertilizer to solve the above problems. SUMMARY

[0004] The present application aims to solve the problems in the prior art that the coating layer often only focuses on physical slow release during the preparation of the fertilizer, lacks the function of synergistically providing active substances (such as amino acids and polysaccharides) and trace elements, and the conventional addition method of trace elements is difficult to ensure the stability and bioavailability thereof, and provides a preparation method of functional medium and trace element fertilizer.

[0005] The preparation method of functional medium and trace element fertilizer provided in the present application adopts the following technical scheme: A preparation method of functional medium and trace element fertilizer, comprising the following steps: S1: batching: 15-30 parts of straw, 5-15 parts of soybean meal, 3-10 parts of molasses, 0.1-0.5 parts of Bacillus subtilis, 0.05-0.15 parts of nitrogen-fixing bacteria, 0.05-0.15 parts of phosphorus-solubilizing bacteria, 0.05-0.15 parts of Trichoderma, 10-30 parts of nitrogen, phosphorus and potassium fertilizer, 2-8 parts of humic acid, 5-15 parts of ferrous sulfate, 5-15 parts of zinc sulfate, 3-10 parts of manganese sulfate, 3-10 parts of boric acid, 1-5 parts of sodium molybdate, 2-8 parts of sodium alginate, 3-10 parts of chitosan, and 1-5 parts of serine; S2: pretreating the raw materials; S3: mixing the pretreated raw materials in proportion and adjusting them; S4: adding bacterial agents to the mixed raw materials and performing composting fermentation on the raw materials after adding the bacterial agents; S5: crushing and screening the fermented mixed materials and adjusting the nutrients thereof; S6: granulating and forming the adjusted mixed materials to obtain base organic granules; S7: The raw materials are mixed and dissolved to obtain a coating agent solution, and the base organic particles are pretreated; S8: The base organic particles are coated with the coating agent solution, and the coated particles are dried and cooled to obtain the finished fertilizer product.

[0006] Further, in S1, the straw is 20-25 parts, the soybean meal is 8-12 parts, the molasses is 5-8 parts, the Bacillus subtilis is 0.2-0.4 parts, the nitrogen-fixing bacteria is 0.08-0.12 parts, the phosphorus-solubilizing bacteria is 0.08-0.12 parts, the Trichoderma is 0.08-0.12 parts, the nitrogen-phosphorus-potassium fertilizer is 15-25 parts, the humic acid is 4-6 parts, the ferrous sulfate is 8-12 parts, the zinc sulfate is 8-12 parts, the manganese sulfate is 5-8 parts, the boric acid is 5-8 parts, the sodium molybdate is 2-4 parts, the sodium alginate is 3-7 parts, the chitosan is 5-8 parts, and the serine is 2-4 parts.

[0007] Further, in S1, the straw is 22 parts, the soybean meal is 10 parts, the molasses is 6 parts, the Bacillus subtilis is 0.3 parts, the nitrogen-fixing bacteria is 0.1 parts, the phosphorus-solubilizing bacteria is 0.1 parts, the Trichoderma is 0.1 parts, the nitrogen-phosphorus-potassium fertilizer is 20 parts, the humic acid is 5 parts, the ferrous sulfate is 10 parts, the zinc sulfate is 10 parts, the manganese sulfate is 6 parts, the boric acid is 6 parts, the sodium molybdate is 3 parts, the sodium alginate is 5 parts, the chitosan is 6 parts, and the serine is 3 parts.

[0008] Further, in S2, the straw and the soybean meal are accurately weighed by a weighing device, the straw is cut into small pieces of 3-8 cm by a pretreatment mechanism, and the straw and the soybean meal are mixed by a mixer, the mixer rotates at a speed of 40-60 rpm, and the mixing time is 10-15 min to ensure that the raw materials are uniformly dispersed.

[0009] Further, in S2, the molasses is added to an appropriate amount of water in proportion, stirred and dissolved by a stirrer, the stirrer rotates at a speed of 300-500 rpm, and the stirring time is 10-15 min to fully dissolve the molasses and form a uniform molasses solution, which is ready for use. The Bacillus subtilis, the nitrogen-fixing bacteria, the phosphorus-solubilizing bacteria, and the Trichoderma are diluted with sterile water in a proportion of 1:10-1:100, respectively, and activated at 25-30℃ for 30-60 min, which is ready for use.

[0010] Further, in S3 and S4, the mixture of pretreated straw and soybean meal is mixed with the dissolved molasses solution in proportion, stirred uniformly, the moisture content is adjusted to 60% ± 2% by adding water, and the carbon-nitrogen ratio is adjusted to 28-32 by using a carbon-nitrogen ratio regulator (such as urea or superphosphate). The mixing process is carried out in a stirrer, the stirrer speed is 300-500 rpm, and the stirring time is 15-20 min, to ensure that the ingredients are fully contacted. Activated Bacillus subtilis, nitrogen-fixing bacteria, phosphorus-solubilizing bacteria, and Trichoderma are added to the mixed organic substrate respectively, stirred uniformly, and inoculated on the organic substrate. The stirrer speed is 200-300 rpm, and the stirring time is 10-15 min. The inoculated organic substrate is stacked into a pile, the pile height is 1.5-2 m, the width is 2-3 m, and the length is not limited. The aerobic pile fermentation method is used, the pile is turned over once a day for the first 3-5 days, and then once every 2-3 days. The fermentation temperature is controlled below 60°C. If the temperature exceeds 60°C, the pile is turned over immediately to reduce the temperature. The fermentation is carried out for 30-35 days until the organic substrate is fully composted. The composting indicators are that the pile temperature is stable within 10°C of the ambient temperature, the material color is dark brown, and there is no odor.

[0011] Further, in S5, the fermented compost is crushed by a hammer crusher to a particle size of 2-3 mm. The crushed material is screened by a vibrating screen to remove impurities and large particles, ensuring uniform particle size of the crushed material. According to the nutrient requirements of the target fertilizer, nitrogen, phosphorus, and potassium fertilizers are added to the crushed material in proportion. For example, if the target total nutrient content is 15%, the required amount of fertilizer to be supplemented is calculated based on the existing nitrogen, phosphorus, and potassium content of the crushed material. The crushed material and fertilizer are mixed by a horizontal stirrer at a speed of 400-600 rpm for 5-10 min, to ensure uniform distribution of nutrients and a total solid nutrient content of 10%-20%. An appropriate amount of humic acid is added to the mixed material as a binder, and the amount of humic acid is 2%-5% of the mass of the mixed material.

[0012] Further, in S6, the mixed material is made into particles with a diameter of 3-5 mm using an extrusion granulator. The extrusion pressure of the extrusion granulator is 10-20 MPa, the die hole diameter is 3-5 mm, and the die speed is 500-800 rpm. The prepared particles should have a smooth surface, no cracks, and a particle strength of 5-10 N / particle (using particles with a particle size of 4 mm, the peak force is measured when the particles are compressed to break under a universal testing machine at a speed of 1 mm / min).

[0013] Further, in the S7, the ferrous sulfate, zinc sulfate, manganese sulfate, boric acid and sodium molybdate are respectively dissolved in water in proportion, for example, 10 parts of ferrous sulfate, 10 parts of zinc sulfate, 6 parts of manganese sulfate, 6 parts of boric acid and 3 parts of sodium molybdate are weighed, and an appropriate amount of water (the amount of water is about 5-10 times the total mass of the solid) is added, and mixed and dissolved by a magnetic stirrer, the stirring speed of the magnetic stirrer is 300-500 rpm, and the stirring time is 20-30 min, so that it is fully dissolved and mixed, to obtain a trace element solution for standby; Boric acid (H3BO3) dissociates in water to provide boron elements: ; Sodium molybdate (Na2MoO4) releases molybdate ions: ; Ferrous / zinc / manganese sulfate (such as EDTA-Fe) maintains the solubility of metal ions: ; Sodium alginate, chitosan and serine are added to an appropriate amount of water in proportion (the amount of water is about 10-15 times the total mass of the solid), heated to 60-80℃, and stirred and dissolved by a stirrer, the stirring speed of the stirrer is 300-500 rpm, and the stirring time is 1-2 h, so that it is fully dissolved and mixed to form a coating agent solution, for example, 5 parts of sodium alginate, 6 parts of chitosan and 3 parts of serine are weighed, and an appropriate amount of water is added to obtain a uniform coating agent solution for standby; Sodium alginate (NaAlg) forms a gel film with divalent cations (such as Ca 2+ ): ; Chitosan dissolves in weakly acidic conditions (H + from humic acid or water) to form a cationic polymer solution: ; After drying, a dense film is formed.

[0014] Further, in the S8, the prepared base organic particles are put into a one-step film forming large rotary drum coating machine, the rotating speed of the coating machine is 20-30 rpm / min, the temperature is 35-40 DEG C, the prepared trace element solution is atomized and sprayed through the spraying equipment arranged in the drum, the spraying flow of the spraying equipment is 1-2 L / min, the atomized particle size is 50-80 mu m, the spraying angle is 60-80 DEG, the spraying time is about 5-10 min, so that the trace element solution is uniformly adsorbed on the surface of the particles, then the coating agent solution is sprayed through the spraying equipment in the same drum, at this time, the spraying flow of the spraying equipment is 1-3 L / min, the atomized particle size is 80-100 mu m, the spraying angle is 80-90 DEG, and the spraying time is 10-15 min, so that a uniform coating layer of the coating agent is formed on the surface of the particles, the spraying flow and time are adjusted, so that the coating thickness reaches 0.1-0.3 mm, the coated particles are sent into a belt dryer, drying treatment is carried out at a temperature of 35-40 DEG C, the drying time is 1-2 h, the moisture content of the particles is reduced to below 10%, the air speed of the dryer is 1-2 m / s, the air volume is adjustable, the particles are uniformly heated, and the particles are prevented from being broken, the dried particles are sent into a cooling equipment, natural ventilation or forced ventilation is adopted, the particles are cooled to room temperature (20-25 DEG C), the cooling time is 10-15 min, and the fertilizer finished product is obtained.

[0015] In summary, the present application has at least one of the following beneficial technical effects: 1. The present application combines sodium alginate, chitosan and serine to form a coating agent, which not only realizes physical slow release of the base organic particles, but also provides active substances (such as amino acids and polysaccharides) and trace elements, so that the nutrient release of the fertilizer is more in line with the growth needs of crops, the fertilizer efficiency is prolonged, the nutrient loss is reduced, and the fertilizer utilization rate is improved. 2. The present application uses chelated (sulfate) trace elements such as ferrous sulfate, zinc sulfate and manganese sulfate, and a specific coating process, so that the stability of the trace elements is significantly improved during the storage and transportation of the fertilizer, the problem that the trace elements are easily fixed in the soil and difficult to be absorbed by plants in the prior art is effectively solved, so as to promote the absorption of trace elements by plants, prevent and correct plant deficiency, and improve crop quality.

[0016] The present application uses straw, soybean meal, molasses, bacillus subtilis, nitrogen-fixing bacteria, phosphorus solubilizing bacteria, trichoderma, nitrogen, phosphorus and potassium fertilizer, humic acid, ferrous sulfate, zinc sulfate, manganese sulfate, boric acid, sodium molybdate, sodium alginate, chitosan and serine, so as to effectively solve the problems of single coating function, poor stability and low biological availability of trace elements in the preparation process of the fertilizer. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1A flow chart of a functional medium and trace element fertilizer preparation method according to the present application; Figure 2 A flow chart of S2 of a functional medium and trace element fertilizer preparation method according to the present application; Figure 3 A flow chart of S3 of a functional medium and trace element fertilizer preparation method according to the present application; Figure 4 A flow chart of S4 of a functional medium and trace element fertilizer preparation method according to the present application; Figure 5 A flow chart of S5 of a functional medium and trace element fertilizer preparation method according to the present application; Figure 6 A flow chart of S7 of a functional medium and trace element fertilizer preparation method according to the present application; Figure 7 A flow chart of S8 of a functional medium and trace element fertilizer preparation method according to the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application.

[0019] Embodiment one Reference Figures 1-7 A functional medium and trace element fertilizer preparation method, comprising the following steps: S1: batching: 15 parts of straw, 5 parts of soybean meal, 3 parts of molasses, 0.1 part of Bacillus subtilis, 0.05 part of nitrogen-fixing bacteria, 0.05 part of phosphorus-solubilizing bacteria, 0.05 part of Trichoderma, 10 parts of nitrogen, phosphorus and potassium fertilizer, 2 parts of humic acid, 5 parts of ferrous sulfate, 5 parts of zinc sulfate, 3 parts of manganese sulfate, 3 parts of boric acid, 1 part of sodium molybdate, 2 parts of sodium alginate, 3 parts of chitosan, and 1 part of serine; S2: accurately weighing straw and soybean meal in proportion by a weighing device, chopping the straw into 8 cm small segments by a pretreatment mechanism to increase its specific surface area for subsequent mixing and fermentation, mixing the straw and soybean meal by a mixer, the mixer speed is 60 rpm, the mixing time is 15 min, ensuring that the raw materials are evenly dispersed, adding molasses to an appropriate amount of water in proportion (the amount of water is about 3-5 times the amount of molasses), stirring and dissolving by a stirrer, the stirrer speed is 500 rpm, the stirring time is 15 min, so that the molasses is fully dissolved to form a uniform molasses solution, and set aside, diluting Bacillus subtilis, nitrogen-fixing bacteria, phosphate-solubilizing bacteria and Trichoderma with sterile water at a ratio of 1:10-1:100, for example, taking 1 g of the inoculum and adding 10-100 ml of sterile water, stirring fully to disperse it evenly, and standing at 30°C for 60 min to activate the inoculum, and set aside; S3: The pretreated straw and soybean meal mixture is mixed with the dissolved molasses solution in proportion and stirred evenly. Water is added to adjust the moisture content to 60% ± 2%, and a carbon-nitrogen ratio regulator (such as urea or superphosphate) is used to adjust the carbon-nitrogen ratio to 28-32. The mixing process is carried out in a blender at a speed of 500 rpm for 20 minutes to ensure full contact between the ingredients. S4: Add activated Bacillus subtilis, nitrogen-fixing bacteria, phosphate-solubilizing bacteria and Trichoderma to the mixed organic matrix respectively, stir evenly, so that the bacterial agent is fully inoculated on the organic matrix, the mixer speed is 300 rpm, the stirring time is 15 min, and the inoculated organic matrix is ​​piled into a pile with a height of 2 m and a width of 3 m. The length is not limited. Aerobic turning and fermentation are adopted. The pile is turned once a day for the first 5 days and once every 3 days thereafter. The fermentation temperature is controlled below 60°C. If the temperature exceeds 60°C, the pile is immediately turned to cool down. The fermentation is carried out for 35 days until the organic matrix is ​​fully decomposed. The decomposition maturity sign is that the pile temperature is stable within 10°C of the ambient temperature, the material color turns dark brown, and there is no odor. S5: Use a hammer mill to crush the fermented compost to a particle size of 3mm. Use a vibrating screen to screen the crushed material to remove impurities and larger particles to ensure uniform particle size. Add nitrogen, phosphorus, and potassium fertilizers to the crushed material in proportion to the target fertilizer's nutrient requirements. For example, if the target total nutrient content is 15%, calculate the amount of fertilizer required based on the existing nitrogen, phosphorus, and potassium content of the crushed material. Use a horizontal mixer to mix the crushed material and fertilizer at a speed of 600rpm for 10 minutes to ensure uniform nutrient distribution and a total solid nutrient content of 20%. Add an appropriate amount of humic acid to the mixture as a binder. The amount of humic acid is 5% of the mass of the mixture. S6: The mixture is made into 5mm diameter particles using an extrusion granulator with an extrusion pressure of 20MPa, a die aperture of 5mm, and a die speed of 800rpm. The resulting particles should be smooth and crack-free, with a particle strength of 10N / particle (using 4mm particles, compress at a rate of 1mm / min on a universal testing machine until the peak force is reached); S7: Dissolve the ferrous sulfate, zinc sulfate, manganese sulfate, boric acid, and sodium molybdate in water in the appropriate proportions. For example, take 10 parts of ferrous sulfate, 10 parts of zinc sulfate, 6 parts of manganese sulfate, 6 parts of boric acid, and 3 parts of sodium molybdate, and add an appropriate amount of water (about 5-10 times the total mass of the solids). Mix and dissolve using a magnetic stirrer at a speed of 300rpm for 20 minutes to ensure complete dissolution. The resulting trace element solution is ready for use. Boric acid (H3BO3) dissociates in water to provide boron: ; Sodium molybdate (Na2MoO4) releases molybdate ions: ; Ferrous / zinc / manganese sulfate (e.g. EDTA-Fe) maintains metal ion solubility: ; Dissolve the sodium alginate, chitosan, and serine in water in the appropriate proportions (about 10-15 times the total mass of the solids). Heat to 60°C and stir using a stirrer at a speed of 300rpm for 1 hour to ensure complete dissolution. The resulting coating agent solution is ready for use. Sodium alginate (NaAlg) forms a gel film with divalent cations (e.g. Ca 2+ ): ; Chitosan dissolves in weakly acidic conditions (H + from humic acid or water) to form a cationic polymer solution: ; After drying, a dense film is formed. S8: Put the prepared base organic particles into a one-step film forming large rotary drum coating machine, the rotating speed of the coating machine is 20 rpm / min, the temperature is 35℃, the prepared microelement liquid is atomized and sprayed through the spraying equipment arranged in the drum, the spraying flow of the spraying equipment is 1 L / min, the atomized particle size is 50 μm, the spraying angle is 60°, and the spraying time is about 5 min, so that the microelement liquid is uniformly adsorbed on the surface of the particles, then the coating agent solution is sprayed through the spraying equipment in the same drum, at this time, the spraying flow of the spraying equipment is 1 L / min, the atomized particle size is 80 μm, the spraying angle is 80°, and the spraying time is 10 min, so that a uniform coating of the coating agent is formed on the surface of the particles, the spraying flow and time are adjusted to make the coating thickness reach 0.3 mm, the coated particles are sent into a belt dryer, drying treatment is carried out at a temperature of 40℃, the drying time is 2 h, the moisture content of the particles is reduced to below 10%, the air speed of the dryer is 2 m / s, and the air volume is adjustable, so that the particles are uniformly heated and the particles are prevented from being broken, the dried particles are sent into a cooling equipment, natural ventilation or forced ventilation is adopted, the particles are cooled to room temperature 25℃, the cooling time is 15 min, and a finished fertilizer product is obtained.

[0020] Example Two With reference to Figures 1-7 A preparation method of a functional microelement fertilizer, comprising the following steps: S1: proportioning: 18 parts of straw, 8 parts of soybean meal, 5 parts of molasses, 0.2 parts of bacillus subtilis, 0.08 parts of nitrogen-fixing bacteria, 0.08 parts of phosphorus solubilizing bacteria, 0.08 parts of trichoderma, 15 parts of nitrogen, phosphorus and potassium fertilizer, 3 parts of humic acid, 8 parts of ferrous sulfate, 8 parts of zinc sulfate, 5 parts of manganese sulfate, 5 parts of boric acid, 2 parts of sodium molybdate, 3 parts of sodium alginate, 5 parts of chitosan and 2 parts of serine; S2: accurately weighing the straw and soybean meal by a weighing device according to the proportion, cutting the straw into small pieces of 8 cm by a pretreatment mechanism to increase the specific surface area and facilitate subsequent mixing and fermentation, mixing the straw and soybean meal by a mixer, the rotating speed of the mixer is 60 rpm, and the mixing time is 15 min, so that the raw materials are uniformly dispersed, dissolving the molasses in an appropriate amount of water (the amount of water is about 3-5 times the amount of molasses) by a stirrer, the rotating speed of the stirrer is 500 rpm, and the stirring time is 15 min, so that the molasses is fully dissolved to form a uniform molasses solution, and the bacillus subtilis, nitrogen-fixing bacteria, phosphorus solubilizing bacteria and trichoderma are diluted with sterile water according to a proportion of 1:10-1:100, for example, 1 g of bacterial agent is added into 10-100 ml of sterile water, and the bacterial agent is uniformly dispersed by stirring, and is activated at 30℃ for 60 min. S3: Mix the pretreated straw and soybean meal mixture with the dissolved molasses solution in proportion, stir evenly, adjust the moisture content to 60% ± 2% by adding water, and adjust the carbon-nitrogen ratio to 28-32 using a carbon-nitrogen ratio regulator (such as urea or superphosphate). The mixing process is carried out in a blender, the blender speed is 500 rpm, and the stirring time is 20 minutes to ensure that all ingredients are fully contacted; S4: Add activated Bacillus subtilis, nitrogen-fixing bacteria, phosphorus-dissolving bacteria, and Trichoderma to the mixed organic substrate, stir evenly, and inoculate the bacteria to the organic substrate. The blender speed is 300 rpm, and the stirring time is 15 minutes. The inoculated organic substrate is stacked into a pile with a height of 2 m, a width of 3 m, and a length not limited. The fermentation is carried out by aerobic turning, turning once a day for the first 5 days, then turning every 3 days. The fermentation temperature is controlled below 60°C. If the temperature exceeds 60°C, turn the pile immediately to reduce the temperature. The fermentation is carried out for 35 days until the organic substrate is fully composted. The composting indicators are that the pile temperature is stable within 10°C of the ambient temperature, the material color is dark brown, and there is no odor. S5: The fermented compost is crushed by a hammer crusher to a particle size of 3 mm. The crushed material is screened by a vibrating screen to remove impurities and large particles, ensuring uniform particle size of the crushed material. According to the nutrient requirements of the target fertilizer, nitrogen, phosphorus, and potassium fertilizers are added to the crushed material in proportion. For example, if the target total nutrient content is 15%, the required amount of fertilizer to be supplemented is calculated based on the existing nitrogen, phosphorus, and potassium content of the crushed material. The crushed material and fertilizer are mixed by a horizontal stirrer at a speed of 600 rpm for 10 minutes to ensure uniform nutrient distribution and a total solid nutrient content of 20%. An appropriate amount of humic acid is added to the mixture as a binder, with a humic acid dosage of 5% of the mass of the mixture. S6: The mixture is made into particles with a diameter of 5 mm using an extrusion granulator. The extrusion pressure of the extrusion granulator is 20 MPa, the template aperture is 5 mm, and the template speed is 800 rpm. The prepared particles should have a smooth surface, no cracks, and a particle strength of 10 N / particle (using particles with a particle size of 4 mm, the peak force is measured when the particles are compressed to break under a universal testing machine at a speed of 1 mm / min). S7: Dissolve ferrous sulfate, zinc sulfate, manganese sulfate, boric acid, and sodium molybdate in water in proportion, for example, take 10 parts of ferrous sulfate, 10 parts of zinc sulfate, 6 parts of manganese sulfate, 6 parts of boric acid, and 3 parts of sodium molybdate, add an appropriate amount of water (the amount of water is about 5-10 times the total mass of solids), mix and dissolve by a magnetic stirrer at a speed of 350 rpm for 22 minutes to ensure complete dissolution and mixing, and obtain a trace element solution for standby. Boric acid (H3BO3) dissociates in water to provide boron elements: ; Sodium molybdate (Na2MoO4) releases molybdate ions: ; Ferrous / zinc / manganese sulfate (as EDTA-Fe) keeps the metal ions soluble: ; Sodium alginate, chitosan and serine are added to an appropriate amount of water in proportion (the amount of water is about 10-15 times the total mass of the solids), heated to 65°C, and stirred and dissolved with a stirrer at a speed of 350 rpm for 1.2 hours to fully dissolve and mix to form a coating agent solution. For example, 5 parts of sodium alginate, 6 parts of chitosan and 3 parts of serine are weighed, and an appropriate amount of water is added to obtain a uniform coating agent solution for later use; Sodium alginate (NaAlg) and divalent cations (such as Ca 2+ ) to form a gel film: ; Chitosan dissolves under weak acidic conditions (H + from humic acid or water), forming a cationic polymer solution: ; After drying, a dense film is formed; S8: Place the prepared basic organic particles into a large rotary drum coating machine for one-step film formation. The speed of the coating machine is 2 rpm / min and the temperature is 36°C. The prepared trace element liquid is sprayed by a spray device set in the drum. The spray flow rate of the spray device is 1.2 L / min, the atomized particle size is 55 μm, the spray angle is 65°, and the spraying time is about 6 minutes. The trace element liquid is uniformly adsorbed on the particle surface. Then, the coating agent solution is sprayed by the spray device in the same drum. At this time, the spray flow rate of the spray device is 1.2 L / min, the atomized particle size is 85 μm, and the spray angle is 82°, spraying time is 11 minutes, so that the coating agent forms a uniform coating on the surface of the particles. By adjusting the spray flow rate and time, the coating thickness reaches 0.3mm, and the coated particles are sent to the belt dryer and dried at a temperature of 40℃ for 2 hours to reduce the moisture content of the particles to below 10%. The wind speed of the dryer is 2m / s, and the air volume is adjustable to ensure that the particles are heated evenly and avoid particle cracking. The dried particles are sent to the cooling equipment and cooled to room temperature of 25℃ by natural ventilation or forced ventilation. The cooling time is 15 minutes to obtain the finished fertilizer.

[0021] Example 3 Reference Figures 1-7 A method for preparing a functional medium and trace element fertilizer comprises the following steps: S1: ingredients: straw 20 parts, soybean meal 10 parts, molasses 6 parts, bacillus subtilis 0.3 parts, nitrogen-fixing bacteria 0.1 parts, phosphorus solubilizing bacteria 0.1 parts, trichoderma 0.1 parts, nitrogen, phosphorus and potassium fertilizer 20 parts, humic acid 5 parts, ferrous sulfate 10 parts, zinc sulfate 10 parts, manganese sulfate 6 parts, boric acid 6 parts, sodium molybdate 3 parts, sodium alginate 4 parts, chitosan 6 parts, serine 3 parts; S2: accurately weigh the straw and soybean meal by the weighing device, cut the straw into 8cm pieces by the pretreatment mechanism to increase its specific surface area, facilitate subsequent mixing and fermentation, mix the straw and soybean meal by the mixer, the mixer speed is 60rpm, the mixing time is 15min, ensure that the raw materials are evenly dispersed, add the molasses to the water in proportion (the amount of water is about 3-5 times the amount of molasses), stir and dissolve by the stirrer, the stirrer speed is 500rpm, the stirring time is 15min, make the molasses fully dissolved, form a uniform molasses solution, and reserve, dilute the bacillus subtilis, nitrogen-fixing bacteria, phosphorus solubilizing bacteria and trichoderma with sterile water in the ratio of 1:10-1:100, for example, take 1g of bacterial agent and add 10-100ml of sterile water, stir well to make it evenly dispersed, activate at 30℃ for 60min, and reserve; S3: mix the pretreated straw and soybean meal mixture with the dissolved molasses solution in proportion, stir evenly, add water to adjust the moisture content to 60%±2%, and use carbon-nitrogen ratio adjuster (such as urea or superphosphate) to adjust the carbon-nitrogen ratio to 28-32, the mixing process is carried out in the stirrer, the stirrer speed is 500rpm, the stirring time is 20min, ensure that the components are fully contacted; S4: add the activated bacillus subtilis, nitrogen-fixing bacteria, phosphorus solubilizing bacteria and trichoderma to the mixed organic substrate respectively, stir evenly, inoculate the bacterial agent to the organic substrate, the stirrer speed is 300rpm, the stirring time is 15min, pile the inoculated organic substrate into a pile, the pile height is 2m, the width is 3m, the length is unlimited, use aerobic turning pile fermentation method, turn the pile once a day for the first 5 days, then turn the pile once every 3 days, control the fermentation temperature below 60℃, if the temperature exceeds 60℃, immediately turn the pile to reduce the temperature, ferment for 35 days, until the organic substrate is completely composted, the composting sign is that the pile temperature is stable within 10℃ of the ambient temperature, the material color turns dark brown, and there is no odor; S5: The fermented compost is crushed by a hammer crusher, and the crushed particle size is 3 mm. The crushed material is screened by a vibrating screen to remove impurities and large particles, and to ensure uniform particle size of the crushed material. According to the nutrient requirements of the target fertilizer, nitrogen, phosphorus and potassium fertilizers are added to the crushed material in proportion. For example, if the target total nutrient content is 15%, the required amount of fertilizer to be supplemented is calculated according to the existing nitrogen, phosphorus and potassium content of the crushed material. The crushed material and fertilizer are mixed by a horizontal stirrer at a speed of 600 rpm for 10 min to ensure uniform nutrient distribution and a total solid nutrient content of 20%. An appropriate amount of humic acid is added to the mixed material as a binder, and the amount of humic acid is 5% of the mass of the mixed material; S6: The mixed material is made into particles with a diameter of 5 mm using an extrusion granulator. The extrusion pressure of the extrusion granulator is 20 MPa, the template aperture is 5 mm, and the template speed is 800 rpm. The prepared particles should have a smooth surface, no cracks, and a particle strength of 10 N / particle (using particles with a particle size of 4 mm, the peak force is compressed to break under a universal testing machine at a speed of 1 mm / min). S7: Ferrous sulfate, zinc sulfate, manganese sulfate, boric acid and sodium molybdate are dissolved in water in proportion, for example, 10 parts of ferrous sulfate, 10 parts of zinc sulfate, 6 parts of manganese sulfate, 6 parts of boric acid and 3 parts of sodium molybdate are weighed, and an appropriate amount of water (about 5-10 times the total mass of solids) is added. The mixture is dissolved by a magnetic stirrer at a speed of 400 rpm for 24 min to ensure complete dissolution and mixing, and a trace element solution is obtained for standby; Boric acid (H3BO3) dissociates in water to provide boron elements: ; Sodium molybdate (Na2MoO4) releases molybdate ions: ; Ferrous / zinc / manganese sulfate (e.g. EDTA-Fe) maintains metal ion solubility: ; Sodium alginate, chitosan and serine are added to an appropriate amount of water in proportion (about 10-15 times the total mass of solids), heated to 70°C, and stirred by a stirrer at a speed of 400 rpm for 1.4 h to ensure complete dissolution and mixing, forming a coating agent solution. For example, 5 parts of sodium alginate, 6 parts of chitosan and 3 parts of serine are weighed, and an appropriate amount of water is added to obtain a uniform coating agent solution for standby; Sodium alginate (NaAlg) forms a gel film with divalent cations (such as Ca 2+ ): ; Chitosan dissolves in weakly acidic conditions (H + from humic acid or water), forming a cationic polymer solution: ; After drying, a dense film is formed; S8: Put the prepared base organic granules into a one-step film-forming large rotary drum coating machine, the rotating speed of the coating machine is 24 rpm / min, the temperature is 37℃, the prepared trace element liquid is atomized and sprayed through the spraying equipment set in the drum, the spraying flow of the spraying equipment is 1.5 L / min, the atomized particle size is 60 μm, the spraying angle is 70°, the spraying time is about 7 min, so that the trace element liquid is uniformly adsorbed on the surface of the granules, then the coating agent solution is sprayed through the spraying equipment in the same drum, at this time the spraying flow of the spraying equipment is 1.5 L / min, the atomized particle size is 90 μm, the spraying angle is 85°, the spraying time is 12 min, so that a uniform coating of the coating agent is formed on the surface of the granules, by adjusting the spraying flow and time, the coating thickness reaches 0.3 mm, the coated granules are sent into a belt dryer, dried at a temperature of 40℃ for 2 h, so that the moisture content of the granules is reduced to below 10%, the air speed of the dryer is 2 m / s, the air volume is adjustable, to ensure uniform heating of the granules and avoid breakage of the granules, the dried granules are sent into a cooling equipment, and natural ventilation or forced ventilation is used to cool the granules to room temperature 25℃, the cooling time is 15 min, to obtain the finished fertilizer product.

[0022] Example Four Referring to Figures 1-7 A method for preparing a functional microelement fertilizer, comprising the following steps: S1: batching: 25 parts of straw, 12 parts of soybean meal, 8 parts of molasses, 0.4 parts of Bacillus subtilis, 0.12 parts of nitrogen-fixing bacteria, 0.12 parts of phosphorus-solubilizing bacteria, 0.12 parts of Trichoderma, 25 parts of nitrogen, phosphorus and potassium fertilizer, 7 parts of humic acid, 12 parts of ferrous sulfate, 12 parts of zinc sulfate, 8 parts of manganese sulfate, 8 parts of boric acid, 4 parts of sodium molybdate, 6 parts of sodium alginate, 8 parts of chitosan, and 4 parts of serine; S2: accurately weighing straw and soybean meal in proportion by a weighing device, chopping the straw into 8 cm small segments by a pretreatment mechanism to increase its specific surface area for subsequent mixing and fermentation, mixing the straw and soybean meal by a mixer, the mixer speed is 60 rpm, the mixing time is 15 min, ensuring that the raw materials are evenly dispersed, adding molasses to an appropriate amount of water in proportion (the amount of water is about 3-5 times the amount of molasses), stirring and dissolving by a stirrer, the stirrer speed is 500 rpm, the stirring time is 15 min, so that the molasses is fully dissolved to form a uniform molasses solution, and set aside, diluting Bacillus subtilis, nitrogen-fixing bacteria, phosphate-solubilizing bacteria and Trichoderma with sterile water at a ratio of 1:10-1:100, for example, taking 1 g of the inoculum and adding 10-100 ml of sterile water, stirring fully to disperse it evenly, and standing at 30°C for 60 min to activate the inoculum, and set aside; S3: The pretreated straw and soybean meal mixture is mixed with the dissolved molasses solution in proportion and stirred evenly. Water is added to adjust the moisture content to 60% ± 2%, and a carbon-nitrogen ratio regulator (such as urea or superphosphate) is used to adjust the carbon-nitrogen ratio to 28-32. The mixing process is carried out in a blender at a speed of 500 rpm for 20 minutes to ensure full contact between the ingredients. S4: Add activated Bacillus subtilis, nitrogen-fixing bacteria, phosphate-solubilizing bacteria and Trichoderma to the mixed organic matrix respectively, stir evenly, so that the bacterial agent is fully inoculated on the organic matrix, the mixer speed is 300 rpm, the stirring time is 15 min, and the inoculated organic matrix is ​​piled into a pile with a height of 2 m and a width of 3 m. The length is not limited. Aerobic turning and fermentation are adopted. The pile is turned once a day for the first 5 days and once every 3 days thereafter. The fermentation temperature is controlled below 60°C. If the temperature exceeds 60°C, the pile is immediately turned to cool down. The fermentation is carried out for 35 days until the organic matrix is ​​fully decomposed. The decomposition maturity sign is that the pile temperature is stable within 10°C of the ambient temperature, the material color turns dark brown, and there is no odor. S5: Use a hammer mill to crush the fermented compost to a particle size of 3mm. Use a vibrating screen to screen the crushed material to remove impurities and larger particles to ensure uniform particle size. Add nitrogen, phosphorus, and potassium fertilizers to the crushed material in proportion to the target fertilizer's nutrient requirements. For example, if the target total nutrient content is 15%, calculate the amount of fertilizer required based on the existing nitrogen, phosphorus, and potassium content of the crushed material. Use a horizontal mixer to mix the crushed material and fertilizer at a speed of 600rpm for 10 minutes to ensure uniform nutrient distribution and a total solid nutrient content of 20%. Add an appropriate amount of humic acid to the mixture as a binder. The amount of humic acid is 5% of the mass of the mixture. S6: The mixture is made into 5mm diameter particles using an extrusion granulator with an extrusion pressure of 20MPa, a die aperture of 5mm, and a die speed of 800rpm. The resulting particles should be smooth and crack-free, with a particle strength of 10N / particle (using 4mm diameter particles, compressing at a rate of 1mm / min on a universal testing machine until the peak force is reached); S7: Iron sulfate, zinc sulfate, manganese sulfate, boric acid, and sodium molybdate are dissolved in water in the appropriate proportions. For example, 10 parts of iron sulfate, 10 parts of zinc sulfate, 6 parts of manganese sulfate, 6 parts of boric acid, and 3 parts of sodium molybdate are weighed out, and an appropriate amount of water (about 5-10 times the total mass of the solids) is added. The mixture is dissolved and mixed using a magnetic stirrer at a speed of 450rpm for 28 minutes, until it is fully dissolved and mixed. The resulting trace element solution is ready for use. Boric acid (H3BO3) dissociates in water to provide boron elements: ; Sodium molybdate (Na2MoO4) releases molybdate ions: ; Iron / zinc / manganese sulfate (e.g. EDTA-Fe) maintains metal ion solubility: ; Sodium alginate, chitosan, and serine are added to an appropriate amount of water in the appropriate proportions (about 10-15 times the total mass of the solids), heated to 75°C, and stirred using a stirrer at a speed of 300-500rpm for 1.8 hours, until they are fully dissolved and mixed. The resulting coating agent solution is ready for use. Sodium alginate (NaAlg) forms a gel film with divalent cations (e.g. Ca 2+ ): ; Chitosan dissolves in weakly acidic conditions (H + from humic acid or water) to form a cationic polymer solution: ; After drying, a dense film is formed. S8: Put the prepared base organic particles into a one-step film forming large rotary drum coating machine, the rotating speed of the coating machine is 28 rpm / min, the temperature is 38℃, the prepared microelement liquid is atomized and sprayed through the spraying equipment arranged in the drum, the spraying flow of the spraying equipment is 1.8 L / min, the atomized particle size is 75 μm, the spraying angle is 75°, the spraying time is about 8 min, so that the microelement liquid is uniformly adsorbed on the surface of the particles, then the coating agent solution is sprayed through the spraying equipment in the same drum, at this time the spraying flow of the spraying equipment is 1.8 L / min, the atomized particle size is 95 μm, the spraying angle is 88°, the spraying time is 14 min, so that a uniform coating of the coating agent is formed on the surface of the particles, by adjusting the spraying flow and time, the coating thickness reaches 0.3 mm, the coated particles are sent into a belt dryer, the drying temperature is 40℃, the drying time is 2 h, so that the water content of the particles is reduced to below 10%, the air speed of the dryer is 2 m / s, the air volume is adjustable, so that the particles are uniformly heated and the particles are not broken, the dried particles are sent into a cooling equipment, the particles are cooled to room temperature 25℃ by natural ventilation or forced ventilation, the cooling time is 15 min, and the fertilizer finished product is obtained.

[0023] Example Five Reference Figures 1-7 A preparation method of a functional microelement fertilizer, comprising the following steps: S1: ingredient preparation: 30 parts of straw, 15 parts of soybean meal, 10 parts of molasses, 0.5 parts of bacillus subtilis, 0.15 parts of nitrogen-fixing bacteria, 0.15 parts of phosphorus solubilizing bacteria, 0.15 parts of trichoderma, 30 parts of nitrogen, phosphorus and potassium fertilizer, 8 parts of humic acid, 15 parts of ferrous sulfate, 15 parts of zinc sulfate, 10 parts of manganese sulfate, 10 parts of boric acid, 5 parts of sodium molybdate, 8 parts of sodium alginate, 10 parts of chitosan, and 5 parts of serine; S2: accurately weigh the straw and soybean meal by a weighing device according to the proportion, cut the straw into 8 cm small pieces by a pretreatment mechanism to increase the specific surface area and facilitate subsequent mixing and fermentation, mix the straw and soybean meal by a mixer, the rotating speed of the mixer is 60 rpm, and the mixing time is 15 min, so that the raw materials are uniformly dispersed, add the molasses into water according to the proportion (the water consumption is about 3-5 times of the molasses consumption), and dissolve the molasses by a stirrer, the rotating speed of the stirrer is 500 rpm, and the stirring time is 15 min, so that the molasses is fully dissolved to form a uniform molasses solution, which is ready for use, dilute the bacillus subtilis, nitrogen-fixing bacteria, phosphorus solubilizing bacteria and trichoderma with sterile water according to the proportion of 1:10-1:100, for example, add 1 g of the bacterial agent into 10-100 ml of sterile water, and stir to disperse the bacterial agent uniformly, then activate the bacterial agent at 30℃ for 60 min, and the activated bacterial agent is ready for use; S3: Mix the pretreated straw and soybean meal mixture with the dissolved molasses solution in proportion, stir evenly, adjust the moisture content to 60% ± 2% by adding water, and adjust the carbon-nitrogen ratio to 28-32 using a carbon-nitrogen ratio regulator (such as urea or superphosphate). The mixing process is carried out in a blender, with a speed of 500 rpm and a stirring time of 20 minutes to ensure that all ingredients are fully contacted; S4: Add activated Bacillus subtilis, nitrogen-fixing bacteria, phosphorus-dissolving bacteria, and Trichoderma to the mixed organic substrate, stir evenly, and inoculate the bacteria to the organic substrate. The stirring speed is 300 rpm and the stirring time is 15 minutes. The inoculated organic substrate is stacked into a pile with a height of 2 m, a width of 3 m, and a length not limited. The fermentation is carried out by aerobic turning, with turning once a day for the first 5 days and then every 3 days. The fermentation temperature is controlled below 60°C. If the temperature exceeds 60°C, turn the pile immediately to reduce the temperature. The fermentation is carried out for 35 days until the organic substrate is fully composted. The composting indicators are that the pile temperature is stable within 10°C of the ambient temperature, the material color is dark brown, and there is no odor. S5: The fermented compost is crushed by a hammer crusher to a particle size of 3 mm. The crushed material is screened by a vibrating screen to remove impurities and large particles, ensuring uniform particle size. According to the nutrient requirements of the target fertilizer, nitrogen, phosphorus, and potassium fertilizers are added to the crushed material in proportion. For example, if the target total nutrient content is 15%, the required amount of fertilizer to be supplemented is calculated based on the existing nitrogen, phosphorus, and potassium content of the crushed material. The crushed material and fertilizer are mixed by a horizontal stirrer at a speed of 600 rpm for 10 minutes to ensure uniform nutrient distribution and a total solid nutrient content of 20%. An appropriate amount of humic acid is added to the mixture as a binder, with a humic acid dosage of 2%-5% of the mass of the mixture. S6: The mixture is made into particles with a diameter of 5 mm using an extrusion granulator with an extrusion pressure of 20 MPa, a template aperture of 5 mm, and a template speed of 800 rpm. The resulting particles should have a smooth surface, no cracks, and a particle strength of 10 N / particle (using particles with a diameter of 4 mm, the peak force is measured when the particles are compressed to break under a universal testing machine at a speed of 1 mm / min). S7: Dissolve ferrous sulfate, zinc sulfate, manganese sulfate, boric acid, and sodium molybdate in water in proportion, for example, take 10 parts of ferrous sulfate, 10 parts of zinc sulfate, 6 parts of manganese sulfate, 6 parts of boric acid, and 3 parts of sodium molybdate, add an appropriate amount of water (about 5-10 times the total mass of solids), mix and dissolve by a magnetic stirrer at a speed of 500 rpm for 30 minutes to ensure complete dissolution and mixing, and obtain a trace element solution for later use. Boric acid (H3BO3) dissociates in water to provide boron elements: ; Sodium molybdate (Na2MoO4) releases molybdate ions: ; Ferrous / zinc / manganese sulfate (e.g. EDTA-Fe) maintains metal ion solubility: ; Sodium alginate, chitosan and serine are added to water in a proportion (the amount of water is about 10-15 times the total mass of solids), heated to 80°C, and dissolved by stirring with a stirrer at a speed of 500 rpm for 2 h to form a coating solution. For example, 5 parts of sodium alginate, 6 parts of chitosan and 3 parts of serine are weighed and added to water to obtain a uniform coating solution, which is ready for use. Sodium alginate (NaAlg) forms a gel film with divalent cations (e.g. Ca 2+ ): ; Chitosan dissolves in weakly acidic conditions (H + ) to form a cationic polymer solution: ; After drying, a dense film is formed. S8: The prepared base organic granules are placed in a one-step film-forming large rotary drum coating machine, the rotation speed of which is 30 rpm / min and the temperature is 40°C. The prepared micronutrient solution is atomized and sprayed through the spraying equipment in the drum, the spraying flow rate of the spraying equipment is 2 L / min, the atomized particle size is 80 μm, the spraying angle is 80°, and the spraying time is about 10 min, so that the micronutrient solution is uniformly adsorbed on the surface of the granules. Then the coating solution is sprayed through the spraying equipment in the same drum, at this time the spraying flow rate of the spraying equipment is 3 L / min, the atomized particle size is 100 μm, the spraying angle is 90°, and the spraying time is 15 min, so that a uniform coating layer is formed on the surface of the granules. The thickness of the coating is adjusted by adjusting the spraying flow rate and time to reach 0.3 mm. The coated granules are sent to a belt dryer for drying treatment at a temperature of 40°C for 2 h, so that the water content of the granules is reduced to below 10%. The air speed of the dryer is 2 m / s, and the air volume is adjustable to ensure uniform heating of the granules and avoid breakage of the granules. The dried granules are sent to a cooling device for cooling to room temperature (25°C) by natural or forced ventilation for 15 min to obtain the finished fertilizer product.

[0024] Experimental Example I. Purpose of the experiment The advantages of the fertilizer preparation method of the present application compared with the traditional method include the content of fertilizer nutrients, particle strength, stability and bioavailability of trace elements, etc. II. Experimental materials Raw materials: Prepare raw materials according to the component allocation ratio of Examples 1-5 in the patent document; Equipment: mixer, stirrer, fermentation equipment, pulverizer, granulator, coating equipment, dryer, cooling equipment, etc.; Detection instrument: nutrient analyzer, particle strength tester, trace element analyzer, strain activity detector, etc.; III. Experimental method (1) Experimental group setting According to the raw material ratio and preparation steps of Examples 1-5, five different formula fertilizers were prepared, marked as experimental groups 1-5; (2) Control group setting Traditional fertilizer group: using conventional fertilizer preparation method, without adding the coating agent and specific trace elements in the present application, marked as control group 1; Non-coating treatment group: except for no coating treatment, the rest of the steps are the same as the experimental group, marked as control group 2; Non-bacterium group: without adding any bacterium (Bacillus subtilis, nitrogen-fixing bacteria, phosphorus-solubilizing bacteria, Trichoderma), the rest of the steps are the same as the experimental group, marked as control group 3; (3) Experimental process According to the raw material ratio and preparation method of each group, the fertilizer was prepared; During the preparation process, the process parameters such as fermentation temperature, stirring speed, coating thickness, etc. were strictly controlled; The prepared fertilizer was detected for the following indexes: Total nutrient content (N+P2O5+K2O): the content of nitrogen, phosphorus and potassium in the fertilizer was determined by chemical analysis method, and the total nutrient content was calculated; Particle strength: using particle strength tester, 100 particles were randomly selected for testing, the force required for particle crushing was recorded, and the average value was calculated; Trace element content (Fe, Zn, Mn): the content of ferrous sulfate, zinc sulfate and manganese sulfate in the fertilizer was determined by atomic absorption spectrometry; Bacterium activity: the number and activity of Bacillus subtilis, nitrogen-fixing bacteria, phosphorus-solubilizing bacteria and Trichoderma in the fertilizer were determined by dilution plate method; Fertilizer efficiency test: in the pot experiment, the same plant (such as tomato) was selected, and different groups of fertilizer were applied, and the growth of the plant was observed, including plant height, root length, fresh weight, dry weight and other indexes; IV. Experimental data

[0025] V. Analysis of experimental results Nutrient content: The total nutrient content of the experimental group fertilizer is significantly higher than that of the control group, indicating that the preparation method of the present application can effectively improve the nutrient content of the fertilizer; Particle strength: The particle strength of the experimental group fertilizer is significantly better than that of the control group, indicating that the coating treatment can enhance the strength of the particles and reduce the breakage during transportation and use; Trace element content: The trace element content of the experimental group fertilizer is greatly improved, and with the optimization of raw material ratio, the trace element content gradually increases, proving that the trace element adding method of the present application can improve its stability and content; Virus agent activity: The activity of various types of bacteria in the experimental group fertilizer is much higher than that of the control group, indicating that the preparation process of the present application is beneficial to the survival and activity maintenance of the bacteria; Fertilizer efficiency test: In the pot experiment, the plant height, root length, fresh weight and dry weight of the plants treated with the experimental group fertilizer are better than those of the control group, indicating that the fertilizer of the present application can significantly promote plant growth and improve crop yield and quality.

[0026] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can make equivalent replacement or change according to the technical solution and inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing a functional micro-and oligo-element fertilizer, characterized in that: It comprises the following steps: S1: batching: 15-30 parts of straw, 5-15 parts of soybean meal, 3-10 parts of molasses, 0.1-0.5 parts of bacillus subtilis, 0.05-0.15 parts of nitrogen-fixing bacteria, 0.05-0.15 parts of phosphorus solubilizing bacteria, 0.05-0.15 parts of trichoderma, 10-30 parts of nitrogen, phosphorus and potassium fertilizer, 2-8 parts of humic acid, 5-15 parts of ferrous sulfate, 5-15 parts of zinc sulfate, 3-10 parts of manganese sulfate, 3-10 parts of boric acid, 1-5 parts of sodium molybdate, 2-8 parts of sodium alginate, 3-10 parts of chitosan, 1-5 parts of serine; S2: pretreatment of raw materials; S3: mixing the pretreated raw materials in proportion and adjusting; S4: adding microbial agents to the mixed raw materials and composting and fermenting the raw materials after adding microbial agents; S5: crushing and screening the fermented mixture and adjusting the nutrients; S6: granulating and forming the adjusted mixture to obtain basic organic granules; S7: mixing and dissolving the raw materials to obtain a coating agent solution and pretreating the basic organic granules; S8: coating the surface of the basic organic granules with the coating agent solution and drying and cooling the coated granules to obtain the finished fertilizer.

2. The method for preparing a functional microelement fertilizer according to claim 1, characterized in that: In the S1, 20-25 parts of straw, 8-12 parts of soybean meal, 5-8 parts of molasses, 0.2-0.4 parts of bacillus subtilis, 0.08-0.12 parts of nitrogen-fixing bacteria, 0.08-0.12 parts of phosphorus solubilizing bacteria, 0.08-0.12 parts of trichoderma, 15-25 parts of nitrogen, phosphorus and potassium fertilizer, 4-6 parts of humic acid, 8-12 parts of ferrous sulfate, 8-12 parts of zinc sulfate, 5-8 parts of manganese sulfate, 5-8 parts of boric acid, 2-4 parts of sodium molybdate, 3-7 parts of sodium alginate, 5-8 parts of chitosan, and 2-4 parts of serine.

3. The method for preparing a functional microelement fertilizer according to claim 2, characterized in that: In the S1, 22 parts of straw, 10 parts of soybean meal, 6 parts of molasses, 0.3 parts of bacillus subtilis, 0.1 parts of nitrogen-fixing bacteria, 0.1 parts of phosphorus solubilizing bacteria, 0.1 parts of trichoderma, 20 parts of nitrogen, phosphorus and potassium fertilizer, 5 parts of humic acid, 10 parts of ferrous sulfate, 10 parts of zinc sulfate, 6 parts of manganese sulfate, 6 parts of boric acid, 3 parts of sodium molybdate, 5 parts of sodium alginate, 6 parts of chitosan, and 3 parts of serine.

4. The method for preparing a functional microelement fertilizer according to claim 3, characterized in that: In the S2, the straw and soybean meal are accurately weighed by a weighing device, the straw is cut into 3-8 cm pieces by a pretreatment mechanism, and the straw and soybean meal are mixed by a mixer at a speed of 40-60 rpm for 10-15 min to ensure uniform dispersion of the raw materials.

5. The method for preparing a functional microelement fertilizer according to claim 4, characterized in that: In the S2, the molasses is added to an appropriate amount of water in proportion, stirred and dissolved by a stirrer at a speed of 300-500 rpm for 10-15 min to fully dissolve the molasses and form a uniform molasses solution, the bacillus subtilis, nitrogen-fixing bacteria, phosphorus solubilizing bacteria and trichoderma are diluted with sterile water in a ratio of 1:10-1:100, and the microbial agents are activated at 25-30℃ for 30-60 min.

6. The method for preparing a functional micro-and oligo-element fertilizer according to claim 5, characterized in that: In the S3 and S4, the pretreated straw and soybean meal mixture is mixed with the dissolved molasses solution in proportion, stirred uniformly, the moisture content is adjusted to 60%±2% by adding water, and the carbon-nitrogen ratio is adjusted to 28-32 by using a carbon-nitrogen ratio regulator, the mixing process is carried out in a stirrer, the stirrer speed is 300-500 rpm, and the stirring time is 15-20 min, the activated Bacillus subtilis, nitrogen-fixing bacteria, phosphorus-solubilizing bacteria and Trichoderma are added into the mixed organic substrate respectively, stirred uniformly, and the inoculants are fully inoculated on the organic substrate, the stirrer speed is 200-300 rpm, and the stirring time is 10-15 min, the inoculated organic substrate is stacked into a pile, the pile height is 1.5-2 m, the width is 2-3 m, and the length is unlimited, the aerobic pile fermentation method is adopted, the pile is turned over once a day for the first 3-5 days, and then once every 2-3 days, the fermentation temperature is controlled below 60℃, and the fermentation is carried out for 30-35 days until the organic substrate is completely composted.

7. The method for preparing a functional medium and trace element fertilizer according to claim 6, characterized in that: In the S5, the fermented compost is crushed by a hammer crusher, the crushing particle size is 2-3 mm, the crushed material is screened by a vibrating screen to remove impurities and large particles, and the crushing material particle size is ensured to be uniform, the nitrogen, phosphorus and potassium fertilizers are added into the crushed material in proportion according to the nutrient requirements of the target fertilizer, the crushed material and the fertilizer are mixed by a horizontal stirrer, the horizontal stirrer speed is 400-600 rpm, and the mixing time is 5-10 min, and an appropriate amount of humic acid is added into the mixed material as an adhesive, and the amount of humic acid is 2%-5% of the mass of the mixed material.

8. A method of preparing a functional micro and oligo-element fertilizer according to claim 7, characterized in that: In the S6, the mixed material is made into particles with a diameter of 3-5 mm by using an extrusion granulator, the extrusion pressure of the extrusion granulator is 10-20 MPa, the die hole diameter is 3-5 mm, and the die speed is 500-800 rpm, the prepared particles should be smooth in surface, free of cracks, and the particle strength reaches 5-10 N / particle.

9. The method for preparing a functional microelement fertilizer according to claim 8, characterized in that: In the S7, ferrous sulfate, zinc sulfate, manganese sulfate, boric acid and sodium molybdate are respectively dissolved in water in proportion, mixed and dissolved by a magnetic stirrer, the magnetic stirrer speed is 300-500 rpm, and the stirring time is 20-30 min, so that they are fully dissolved and mixed, and a trace element solution is obtained for standby; Boric acid dissociates in water to provide boron element: ； Sodium molybdate releases molybdate ions: ； Ferrous sulfate / zinc / manganese maintains metal ion solubility: ； Sodium alginate, chitosan and serine are added into an appropriate amount of water in proportion, heated to 60-80℃, and stirred and dissolved by a stirrer, the stirrer speed is 300-500 rpm, and the stirring time is 1-2 h, so that they are fully dissolved and mixed to form a coating agent solution for standby; Sodium alginate forms a gel film with divalent cations: ； Chitosan dissolves in weak acid conditions to form a cationic polymer solution: ； After drying, a dense film is formed.

10. The method for preparing a functional micro-and oligo-element fertilizer according to claim 9, characterized in that: In S8, the prepared base organic particles are put into a one-step film forming large rotary drum coating machine, the rotating speed of the coating machine is 20-30 rpm / min, the temperature is 35-40℃, the prepared trace element liquid is atomized and sprayed through the spraying equipment arranged in the drum, the spraying flow of the spraying equipment is 1-2 L / min, the atomized particle size is 50-80 μm, the spraying angle is 60-80°, the spraying time is about 5-10 min, so that the trace element liquid is uniformly adsorbed on the surface of the particles, then the coating agent solution is continuously sprayed through the spraying equipment in the same drum, at this time the spraying flow of the spraying equipment is 1-3 L / min, the atomized particle size is 80-100 μm, the spraying angle is 80-90°, the spraying time is 10-15 min, so that the coating agent forms a uniform coating on the surface of the particles, the coated particles are sent into a belt dryer, drying treatment is carried out at a temperature of 35-40℃, the drying time is 1-2 h, so that the water content of the particles is reduced to below 10%, the air speed of the dryer is 1-2 m / s, the dried particles are sent into a cooling equipment, natural ventilation or forced ventilation is adopted, the particles are cooled to room temperature, the cooling time is 10-15 min, and the fertilizer finished product is obtained.

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