Microbial fertilizer containing composite biological agent and preparation method thereof

Abstract

The invention relates to the field of microbial fertilizers, in particular to a microbial fertilizer containing a composite biological agent and a preparation method of the microbial fertilizer, which are used for solving the problems that the existing microbial fertilizer has short survival time in soil, the nutrient release speed is difficult to control, and the effects of improving the soil environment and promoting plant growth have certain limitations. According to the preparation method, root development and nutrient absorption of crops can be effectively promoted by adding the composite biological agent, the yield and quality of the crops are improved, a membrane material with good mechanical strength and slow release performance is formed through crosslinking of sodium alginate and chitosan, effective slow release and long-term application of microorganisms and fertilizer are achieved, and the yield and quality of the crops are improved. The utilization rate of the fertilizer is increased, the validity period of the fertilizer is prolonged, the usage amount of the fertilizer is reduced, the growth and yield of crops are effectively improved, and the fertilizer has a good agricultural application prospect.

Description

Technical Field

[0001] The invention relates to the field of microbial fertilizers, and in particular to a microbial fertilizer containing a composite biological bacterial agent and a preparation method thereof. Background Art

[0002] Traditional compound fertilizers are usually mineral-based, which can easily cause soil acidification and environmental pollution. Microbial fertilizers, on the other hand, use microorganisms as their core ingredients, which can effectively promote plant growth, improve soil fertility, and be environmentally friendly. With the growing demand for sustainable agricultural development, microbial fertilizers have attracted widespread attention due to their environmental protection and high efficiency. However, current microbial fertilizers have a short survival time in the soil and the nutrient release rate is difficult to control, which has certain limitations in improving the soil environment and promoting plant growth.

[0003] In view of the above technical defects, a solution is now proposed. Summary of the invention

[0004] In order to overcome the above-mentioned technical problems, the object of the present invention is to provide a microbial fertilizer containing a composite biological agent and a preparation method thereof, wherein corn stalks, dry cow dung, fungus bran, compound fertilizer, composite biological agent, light calcium carbonate, humic acid and earthworm castings are added to a mixer and stirred and mixed, and then granulated by a granulator to obtain composite particles, sodium alginate, chitosan, acetic acid solution and calcium chloride solution are added to the mixer and stirred and mixed, and then cooled to room temperature to obtain a coating liquid, and the composite particles are placed in a fluidized bed coating machine, the coating liquid is sprayed on the rolling composite particles by atomization, and then ventilated and dried to obtain a microbial fertilizer containing a composite biological agent, which solves the problems that the existing microbial fertilizers have a short survival time in the soil, the nutrient release rate is difficult to control, and there are certain limitations in the effect of improving the soil environment and promoting plant growth.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A microbial fertilizer containing a composite biological agent comprises the following components in parts by weight:

[0007] 25-30 parts of corn stalks, 6-12 parts of dry cow dung, 3-9 parts of fungus bran, 5-11 parts of compound fertilizer, 2-12 parts of compound biological agent, 4-6 parts of light calcium carbonate, 1-3 parts of humic acid, 4-10 parts of earthworm castings, 3-5 parts of sodium alginate, 2-3 parts of chitosan, 20-30 parts of acetic acid solution and 15-20 parts of calcium chloride solution;

[0008] Wherein, the composite biological agent is prepared by the following steps:

[0009] Step s1: the cotton straw segments and urea are mixed evenly, and then placed in a tubular furnace, heated to 500-520°C at a heating rate of 8-10°C / min, and then calcined at a constant temperature for 2-3h, and then cooled with the furnace to obtain nitrogen-doped biochar;

[0010] Step s2: Add nitrogen-doped biochar, potassium hydroxide and deionized water into a three-necked flask equipped with a stirrer and a thermometer, stir and react for 20-30 minutes at a temperature of 20-25°C and a stirring rate of 300-400r / min, then heat to 70-75°C and continue stirring and reacting for 8-10 hours. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water for 2-3 times, then place it in a vacuum drying oven, and dry it at a temperature of 60-65°C for 2-3 hours to obtain expanded pore nitrogen-doped biochar;

[0011] Step s3: Add the composite bacterial agent and deionized water into a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introduce nitrogen protection, stir and react for 20-30 minutes at a temperature of 20-25°C and a stirring rate of 300-400r / min, then add the expanded nitrogen-doped biochar and continue stirring and reacting for 30-40 minutes, then freeze-dry to obtain a composite biological bacterial agent.

[0012] As a further solution of the present invention: the usage ratio of the cotton stalk segment and urea in step s1 is 5g:0.5-1.5g; the length of the cotton stalk segment is 1-2cm.

[0013] As a further solution of the present invention: the dosage ratio of the nitrogen-doped biochar, potassium hydroxide and deionized water in step s2 is 10g:7-15g:100-110mL.

[0014] As a further solution of the present invention: the usage ratio of the composite bacterial agent, deionized water and pore-expanded nitrogen-doped biochar in step s3 is 0.1-0.7 g: 30-35 mL: 5 g.

[0015] As a further solution of the present invention: the composite bacterial agent is obtained by mixing nitrogen-fixing bacteria, potassium-solubilizing bacteria and phosphate-solubilizing bacteria in a mass ratio of 4-6:1-3:1-3.

[0016] As a further embodiment of the present invention: the number of viable bacteria in the nitrogen-fixing bacteria is ≥ 2×10 10 cfu / g; the number of viable bacteria in the potassium-dissolving bacteria is ≥ 1×10 10 cfu / g; the number of viable bacteria in the phosphate-solubilizing bacteria is ≥ 1×10 10 cfu / g.

[0017] As a further embodiment of the present invention: the nitrogen-fixing bacteria is one of Rhizobium nodule nitrogen-fixing and Azospirillum brasiliensis.

[0018] As a further embodiment of the present invention: the potassium-solubilizing bacteria is one of Bacillus colloids and Bacillus circulans.

[0019] As a further solution of the present invention: the phosphate-solubilizing bacteria is one of Bacillus megaterium and Pseudomonas.

[0020] As a further solution of the present invention: a method for preparing a microbial fertilizer containing a composite biological agent comprises the following steps:

[0021] Step 1: Weigh 25-30 parts of corn stalks, 6-12 parts of dry cow dung, 3-9 parts of fungus bran, 5-11 parts of compound fertilizer, 2-12 parts of compound biological agent, 4-6 parts of light calcium carbonate, 1-3 parts of humic acid, 4-10 parts of earthworm castings, 3-5 parts of sodium alginate, 2-3 parts of chitosan, 20-30 parts of acetic acid solution and 15-20 parts of calcium chloride solution according to weight;

[0022] Step 2: Add corn stalks, dry cow dung, fungus bran, compound fertilizer, compound biological agent, light calcium carbonate, humic acid and earthworm castings into a mixer, stir and mix for 30-50 minutes at a temperature of 20-25° C. and a stirring rate of 300-400 r / min, and then granulate with a granulator to obtain composite particles with a particle size of 2-3 mm; the model of the compound fertilizer is pure potassium sulfate compound fertilizer 15-15-15-Longmang Phosphorus Chemical;

[0023] Step 3: Add sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stir and mix for 1-1.5 hours at a temperature of 40-45°C and a stirring rate of 300-400 r / min, and then cool to room temperature to obtain a coating solution;

[0024] Step 4: Put the composite particles into a fluidized bed coating machine, spray the coating liquid on the rolling composite particles, and then ventilate and dry them to obtain a microbial fertilizer containing a composite biological agent.

[0025] Beneficial effects of the present invention:

[0026] The invention discloses a microbial fertilizer containing a composite biological agent and a preparation method thereof. The preparation method comprises the following steps: adding corn stalks, dry cow dung, fungus chaff, composite fertilizer, composite biological agent, light calcium carbonate, humic acid and earthworm manure into a mixer for stirring and mixing, and then granulating the mixture through a granulator to obtain composite particles; adding sodium alginate, chitosan, acetic acid solution and calcium chloride solution into the mixer for stirring and mixing, and then cooling the mixture to room temperature to obtain a coating liquid; placing the composite particles into a fluidized bed coating machine, spraying the coating liquid on the rolling composite particles by atomization, and then drying the mixture through ventilation to obtain a microbial fertilizer containing the composite biological agent. The preparation method can effectively promote the root development and nutrient absorption of crops by adding the composite biological agent, and improve the yield and quality of crops; forming a film material with good mechanical strength and slow-release performance by cross-linking sodium alginate and chitosan, and realizing effective slow-release and long-term application of microorganisms and fertilizers, thereby not only improving the utilization rate of the fertilizer, but also extending the effective period of the fertilizer, reducing the amount of fertilizer used, and effectively improving the growth and yield of crops, and having good agricultural application prospects.

[0027] In the process of preparing microbial fertilizer containing composite biological agent, a composite biological agent is first prepared. First, cotton straw segments and urea are calcined to form nitrogen-doped biochar. Then, the nitrogen-doped biochar is treated with potassium hydroxide solution to obtain expanded nitrogen-doped biochar. Finally, the expanded nitrogen-doped biochar is used to load the composite agent to obtain a composite biological agent. The use of agricultural waste cotton straw to prepare biochar realizes the recycling of resources and reduces environmental pollution. In addition, the biochar itself contains a large amount of phosphate, which can be regarded as a long-term slow-release phosphorus resource to realize the direct supply of effective phosphorus in the soil. After being treated with urea and potassium hydroxide, nitrogen is achieved. The doping of elements and potassium can realize the direct supply of effective nitrogen and potassium to the soil, and the alkaline potassium hydroxide solution can dissolve the ash in the biochar pores, reduce the blockage of the internal and external pores of the biochar, and slightly increase the average pore size, thereby improving its adsorption capacity and facilitating the full loading of the composite bacterial agent. After the composite bacterial agent is loaded, the internal pores of the biochar provide a habitat for microorganisms, which improves the survival rate and activity of the microorganisms, prolongs the survival time of the microorganisms, and enriches and supplies the energy required by the microorganisms through adsorption and slow release, promotes the reproduction of microorganisms, and thus realizes a more efficient nutrient cycle in the soil, comprehensively improves soil fertility, and promotes the growth of crops. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1:

[0030] This embodiment is a method for preparing a microbial fertilizer containing a composite biological agent, comprising the following steps:

[0031] Step S1: 5 g of cotton straw segments with a length of 1 cm and 0.5 g of urea are mixed evenly, and then placed in a tubular furnace, heated to 500° C. at a heating rate of 8° C. / min, and then calcined at a constant temperature for 2 h, and then cooled with the furnace to obtain nitrogen-doped biochar;

[0032] Step S2: 10 g of nitrogen-doped biochar, 7 g of potassium hydroxide and 100 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred for reaction at a temperature of 20° C. and a stirring rate of 300 r / min for 20 min, and then the temperature was raised to 70° C. and the stirring reaction was continued for 8 h. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed twice with distilled water, and then placed in a vacuum drying oven and dried at a temperature of 60° C. for 2 h to obtain pore-enlarged nitrogen-doped biochar;

[0033] Step S3: 0.1 g of a composite bacterial agent obtained by mixing nitrogen-fixing bacteria, potassium-solubilizing bacteria and phosphate-solubilizing bacteria in a mass ratio of 4:1:1 and 30 mL of deionized water were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred for 20 min at a temperature of 20 ° C and a stirring rate of 300 r / min, and then 5 g of expanded nitrogen-doped biochar was added to continue stirring for 30 min, and then freeze-dried to obtain a composite biological bacterial agent; the number of viable bacteria in the nitrogen-fixing bacteria was ≥ 2×10 10 cfu / g; the number of viable bacteria in the potassium-dissolving bacteria is ≥ 1×10 10 cfu / g; the number of viable bacteria in the phosphate-solubilizing bacteria is ≥ 1×10 10 cfu / g; the nitrogen-fixing bacteria is stem nodule nitrogen-fixing rhizobium; the potassium-solubilizing bacteria is gelatinous Bacillus; the phosphate-solubilizing bacteria is Bacillus megaterium;

[0034] Step S4: weighing 25 parts of corn stalks, 6 parts of dry cow dung, 3 parts of fungus bran, 5 parts of compound fertilizer, 2 parts of composite biological agent, 4 parts of light calcium carbonate, 1 part of humic acid, 4 parts of earthworm castings, 3 parts of sodium alginate, 2 parts of chitosan, 20 parts of acetic acid solution and 15 parts of calcium chloride solution according to weight;

[0035] Step S5: adding corn stalks, dry cow dung, fungus bran, compound fertilizer, compound biological agent, light calcium carbonate, humic acid and earthworm castings into a mixer, stirring and mixing for 30 minutes at a temperature of 20° C. and a stirring rate of 300 r / min, and then granulating with a granulator to obtain composite particles with a particle size of 2 mm; the model of the compound fertilizer is pure potassium sulfate compound fertilizer 15-15-15-Longmang Phosphorus Chemical;

[0036] Step S6: adding sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stirring and mixing at a temperature of 40° C. and a stirring rate of 300 r / min for 1 h, and then cooling to room temperature to obtain a coating solution;

[0037] Step S7: putting the composite particles into a fluidized bed coating machine, spraying the coating liquid on the rolling composite particles, and then drying them through ventilation to obtain a microbial fertilizer containing the composite biological agent.

[0038] Embodiment 2:

[0039] This embodiment is a method for preparing a microbial fertilizer containing a composite biological agent, comprising the following steps:

[0040] Step S1: 5 g of cotton straw segments with a length of 1.5 cm and 1 g of urea were mixed evenly, and then placed in a tubular furnace, heated to 510° C. at a heating rate of 9° C. / min, and then calcined at a constant temperature for 2.5 h, and then cooled with the furnace to obtain nitrogen-doped biochar;

[0041] Step S2: 10 g of nitrogen-doped biochar, 11 g of potassium hydroxide and 105 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred for reaction at a temperature of 22° C. and a stirring rate of 350 r / min for 25 min, and then the temperature was raised to 72° C. and the stirring reaction was continued for 9 h. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed twice with distilled water, and then placed in a vacuum drying oven and dried at a temperature of 62° C. for 2.5 h to obtain pore-enlarged nitrogen-doped biochar;

[0042] Step S3: 0.4 g of a composite bacterial agent obtained by mixing nitrogen-fixing bacteria, potassium-solubilizing bacteria and phosphate-solubilizing bacteria in a mass ratio of 5:2:2 and 32 mL of deionized water were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred for 25 min at a temperature of 22 ° C and a stirring rate of 350 r / min, and then 5 g of expanded nitrogen-doped biochar was added to continue stirring for 35 min, and then freeze-dried to obtain a composite biological bacterial agent; the number of viable bacteria in the nitrogen-fixing bacteria was ≥ 2×10 10 cfu / g; the number of viable bacteria in the potassium-dissolving bacteria is ≥ 1×10 10cfu / g; the number of viable bacteria in the phosphate-solubilizing bacteria is ≥ 1×10 10 cfu / g; the nitrogen-fixing bacteria is stem-nodulated nitrogen-fixing rhizobium; the potassium-solubilizing bacteria is Bacillus circulans; the phosphate-solubilizing bacteria is Bacillus megaterium;

[0043] Step S4: weighing 28 parts of corn stalks, 9 parts of dry cow dung, 6 parts of fungus bran, 8 parts of compound fertilizer, 7 parts of composite biological agent, 5 parts of light calcium carbonate, 2 parts of humic acid, 7 parts of earthworm castings, 4 parts of sodium alginate, 2.5 parts of chitosan, 25 parts of acetic acid solution and 18 parts of calcium chloride solution according to weight;

[0044] Step S5: adding corn stalks, dry cow dung, fungus bran, compound fertilizer, compound biological agent, light calcium carbonate, humic acid and earthworm castings into a mixer, stirring and mixing for 40 minutes at a temperature of 22° C. and a stirring rate of 350 r / min, and then granulating with a granulator to obtain composite particles with a particle size of 2.5 mm; the model of the compound fertilizer is pure potassium sulfate compound fertilizer 15-15-15-Longmang Phosphorus Chemical;

[0045] Step S6: adding sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stirring and mixing at a temperature of 42° C. and a stirring rate of 350 r / min for 1.2 h, and then cooling to room temperature to obtain a coating solution;

[0046] Step S7: putting the composite particles into a fluidized bed coating machine, spraying the coating liquid on the rolling composite particles, and then drying them through ventilation to obtain a microbial fertilizer containing the composite biological agent.

[0047] Embodiment 3:

[0048] This embodiment is a method for preparing a microbial fertilizer containing a composite biological agent, comprising the following steps:

[0049] Step S1: 5 g of cotton straw segments with a length of 2 cm and 1.5 g of urea were mixed evenly, and then placed in a tubular furnace, heated to 520° C. at a heating rate of 10° C. / min, and then calcined at a constant temperature for 3 h, and then cooled with the furnace to obtain nitrogen-doped biochar;

[0050] Step S2: 10 g of nitrogen-doped biochar, 15 g of potassium hydroxide and 110 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred for reaction at a temperature of 25°C and a stirring rate of 400 r / min for 30 min, and then the temperature was raised to 75°C and the stirring reaction was continued for 10 h. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water for 3 times, and then placed in a vacuum drying oven and dried at a temperature of 65°C for 3 h to obtain pore-enlarged nitrogen-doped biochar;

[0051] Step S3: 0.7 g of a composite bacterial agent obtained by mixing nitrogen-fixing bacteria, potassium-solubilizing bacteria and phosphate-solubilizing bacteria in a mass ratio of 6:3:3 and 35 mL of deionized water are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 25°C and a stirring rate of 400 r / min for 30 min, and then 5 g of expanded nitrogen-doped biochar is added to continue stirring for reaction for 40 min, and then freeze-dried to obtain a composite biological bacterial agent; the number of viable bacteria in the nitrogen-fixing bacteria is ≥ 2×10 10 cfu / g; the number of viable bacteria in the potassium-dissolving bacteria is ≥ 1×10 10 cfu / g; the number of viable bacteria in the phosphate-solubilizing bacteria is ≥ 1×10 10 cfu / g; the nitrogen-fixing bacteria is Azospirillum brasiliensis; the potassium-solubilizing bacteria is Bacillus circulans; the phosphate-solubilizing bacteria is Pseudomonas;

[0052] Step S4: weighing 30 parts of corn stalks, 12 parts of dry cow dung, 9 parts of fungus bran, 11 parts of compound fertilizer, 12 parts of composite biological agent, 6 parts of light calcium carbonate, 3 parts of humic acid, 10 parts of earthworm castings, 5 parts of sodium alginate, 3 parts of chitosan, 30 parts of acetic acid solution and 20 parts of calcium chloride solution according to weight;

[0053] Step S5: adding corn stalks, dry cow dung, fungus bran, compound fertilizer, compound biological agent, light calcium carbonate, humic acid and earthworm castings into a mixer, stirring and mixing for 50 minutes at a temperature of 25° C. and a stirring rate of 400 r / min, and then granulating with a granulator to obtain composite particles with a particle size of 3 mm; the model of the compound fertilizer is pure potassium sulfate compound fertilizer 15-15-15-Longmang Phosphorus Chemical;

[0054] Step S6: adding sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stirring and mixing at a temperature of 45° C. and a stirring rate of 400 r / min for 1.5 h, and then cooling to room temperature to obtain a coating solution;

[0055] Step S7: putting the composite particles into a fluidized bed coating machine, spraying the coating liquid on the rolling composite particles, and then drying them through ventilation to obtain a microbial fertilizer containing the composite biological agent.

[0056] Comparative Example 1:

[0057] This comparative example is a method for preparing a microbial fertilizer containing a composite biological agent, comprising the following steps:

[0058] Step S1: weigh 30 parts of corn stalks, 12 parts of dry cow dung, 9 parts of mushroom bran, 11 parts of compound fertilizer, 6 parts of light calcium carbonate, 3 parts of humic acid, 10 parts of earthworm castings, 5 parts of sodium alginate, 3 parts of chitosan, 30 parts of acetic acid solution and 20 parts of calcium chloride solution according to weight;

[0059] Step S2: adding corn stalks, dry cow dung, mushroom bran, compound fertilizer, light calcium carbonate, humic acid and earthworm castings into a mixer, stirring and mixing for 50 minutes at a temperature of 25° C. and a stirring rate of 400 r / min, and then granulating the mixture with a granulator to obtain composite particles with a particle size of 3 mm; the model of the compound fertilizer is pure potassium sulfate compound fertilizer 15-15-15-Longmang Phosphorus Chemical;

[0060] Step S3: adding sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stirring and mixing at a temperature of 45° C. and a stirring rate of 400 r / min for 1.5 h, and then cooling to room temperature to obtain a coating solution;

[0061] Step S4: putting the composite particles into a fluidized bed coating machine, spraying the coating liquid on the rolling composite particles, and then drying through ventilation to obtain a microbial fertilizer containing the composite biological agent.

[0062] Comparative Example 2:

[0063] This comparative example is a method for preparing a microbial fertilizer containing a composite biological agent, comprising the following steps:

[0064] Step S1: weigh 30 parts of corn stalks, 12 parts of dry cow dung, 9 parts of mushroom bran, 11 parts of compound fertilizer, 12 parts of nitrogen-doped biochar, 6 parts of light calcium carbonate, 3 parts of humic acid, 10 parts of earthworm castings, 5 parts of sodium alginate, 3 parts of chitosan, 30 parts of acetic acid solution and 20 parts of calcium chloride solution according to weight;

[0065] Step S2: adding corn stalks, dry cow dung, fungus bran, compound fertilizer, nitrogen-doped biochar, light calcium carbonate, humic acid and earthworm manure into a mixer, stirring and mixing for 50 minutes at a temperature of 25° C. and a stirring rate of 400 r / min, and then granulating with a granulator to obtain composite particles with a particle size of 3 mm; the model of the compound fertilizer is pure potassium sulfate compound fertilizer 15-15-15-Longmang Phosphorus Chemical;

[0066] Step S3: adding sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stirring and mixing at a temperature of 45° C. and a stirring rate of 400 r / min for 1.5 h, and then cooling to room temperature to obtain a coating solution;

[0067] Step S4: putting the composite particles into a fluidized bed coating machine, spraying the coating liquid on the rolling composite particles, and then drying through ventilation to obtain a microbial fertilizer containing the composite biological agent.

[0068] Comparative Example 3:

[0069] This comparative example is a method for preparing a microbial fertilizer containing a composite biological agent, comprising the following steps:

[0070] Step S1: weigh 30 parts of corn stalks, 12 parts of dry cow dung, 9 parts of mushroom bran, 11 parts of compound fertilizer, 12 parts of expanded nitrogen-doped biochar, 6 parts of light calcium carbonate, 3 parts of humic acid, 10 parts of earthworm castings, 5 parts of sodium alginate, 3 parts of chitosan, 30 parts of acetic acid solution and 20 parts of calcium chloride solution according to weight;

[0071] Step S2: adding corn stalks, dry cow dung, fungus bran, compound fertilizer, expanded nitrogen-doped biochar, light calcium carbonate, humic acid and earthworm manure into a mixer, stirring and mixing for 50 minutes at a temperature of 25° C. and a stirring rate of 400 r / min, and then granulating with a granulator to obtain composite particles with a particle size of 3 mm; the model of the compound fertilizer is pure potassium sulfate compound fertilizer 15-15-15-Longmang Phosphorus Chemical;

[0072] Step S3: adding sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stirring and mixing at a temperature of 45° C. and a stirring rate of 400 r / min for 1.5 h, and then cooling to room temperature to obtain a coating solution;

[0073] Step S4: putting the composite particles into a fluidized bed coating machine, spraying the coating liquid on the rolling composite particles, and then drying through ventilation to obtain a microbial fertilizer containing the composite biological agent.

[0074] Comparative Example 4:

[0075] This comparative example is a method for preparing a microbial fertilizer containing a composite biological agent, comprising the following steps:

[0076] Step S1: Weigh 30 parts of corn stalks, 12 parts of dry cow dung, 9 parts of fungus bran, 11 parts of compound fertilizer, 12 parts of composite bacterial agent obtained by mixing nitrogen-fixing bacteria, potassium-solubilizing bacteria and phosphate-solubilizing bacteria in a mass ratio of 6:3:3, 6 parts of light calcium carbonate, 3 parts of humic acid, 10 parts of earthworm castings, 5 parts of sodium alginate, 3 parts of chitosan, 30 parts of acetic acid solution and 20 parts of calcium chloride solution according to weight; the number of viable bacteria in the nitrogen-fixing bacteria is ≥2×10 10 cfu / g; the number of viable bacteria in the potassium-dissolving bacteria is ≥ 1×10 10 cfu / g; the number of viable bacteria in the phosphate-solubilizing bacteria is ≥ 1×10 10cfu / g; the nitrogen-fixing bacteria is Azospirillum brasiliensis; the potassium-solubilizing bacteria is Bacillus circulans; the phosphate-solubilizing bacteria is Pseudomonas;

[0077] Step S2: adding corn stalks, dry cow dung, fungus bran, compound fertilizer, compound bacterial agent, light calcium carbonate, humic acid and earthworm castings into a mixer, stirring and mixing for 50 minutes at a temperature of 25° C. and a stirring rate of 400 r / min, and then granulating with a granulator to obtain composite particles with a particle size of 3 mm; the model of the compound fertilizer is pure potassium sulfate compound fertilizer 15-15-15-Longmang Phosphorus Chemical;

[0078] Step S3: adding sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stirring and mixing at a temperature of 45° C. and a stirring rate of 400 r / min for 1.5 h, and then cooling to room temperature to obtain a coating solution;

[0079] Step S4: putting the composite particles into a fluidized bed coating machine, spraying the coating liquid on the rolling composite particles, and then drying through ventilation to obtain a microbial fertilizer containing the composite biological agent.

[0080] Comparative Example 5:

[0081] This comparative example is a method for preparing a microbial fertilizer containing a composite biological agent, comprising the following steps:

[0082] Step S1: 5 g of cotton straw segments with a length of 2 cm and 1.5 g of urea were mixed evenly, and then placed in a tubular furnace, heated to 520° C. at a heating rate of 10° C. / min, and then calcined at a constant temperature for 3 h, and then cooled with the furnace to obtain nitrogen-doped biochar;

[0083] Step S2: 0.7 g of a composite bacterial agent obtained by mixing nitrogen-fixing bacteria, potassium-solubilizing bacteria and phosphate-solubilizing bacteria in a mass ratio of 6:3:3 and 35 mL of deionized water are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 25°C and a stirring rate of 400 r / min for 30 min, and then 5 g of nitrogen-doped biochar is added and stirred for reaction for 40 min, and then freeze-dried to obtain a composite biological bacterial agent; the number of viable bacteria in the nitrogen-fixing bacteria is ≥ 2×10 10 cfu / g; the number of viable bacteria in the potassium-dissolving bacteria is ≥ 1×10 10 cfu / g; the number of viable bacteria in the phosphate-solubilizing bacteria is ≥ 1×10 10 cfu / g; the nitrogen-fixing bacteria is Azospirillum brasiliensis; the potassium-solubilizing bacteria is Bacillus circulans; the phosphate-solubilizing bacteria is Pseudomonas;

[0084] Step S3: weighing 30 parts of corn stalks, 12 parts of dry cow dung, 9 parts of fungus bran, 11 parts of compound fertilizer, 12 parts of composite biological agent, 6 parts of light calcium carbonate, 3 parts of humic acid, 10 parts of earthworm castings, 5 parts of sodium alginate, 3 parts of chitosan, 30 parts of acetic acid solution and 20 parts of calcium chloride solution according to weight;

[0085] Step S4: adding corn stalks, dry cow dung, fungus bran, compound fertilizer, compound biological agent, light calcium carbonate, humic acid and earthworm castings into a mixer, stirring and mixing for 50 minutes at a temperature of 25° C. and a stirring rate of 400 r / min, and then granulating with a granulator to obtain composite particles with a particle size of 3 mm; the model of the compound fertilizer is pure potassium sulfate compound fertilizer 15-15-15-Longmang Phosphorus Chemical;

[0086] Step S5: adding sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stirring and mixing at a temperature of 45° C. and a stirring rate of 400 r / min for 1.5 h, and then cooling to room temperature to obtain a coating solution;

[0087] Step S6: putting the composite particles into a fluidized bed coating machine, spraying the coating liquid on the rolling composite particles, and then drying through ventilation to obtain a microbial fertilizer containing the composite biological agent.

[0088] Performance Test:

[0089] Nine soybean test plots were divided in the same test area, each of which was 4 m long and 3 m wide. One of the soybean test plots was used as a blank group, and the remaining eight soybean test plots were used as implementation groups. The microbial fertilizers containing composite biological agents of Examples 1-3 and Comparative Examples 1-5 were added at a rate of 300 kg / hm2. 2 The dosage was used as base fertilizer in 8 soybean test plots of the implementation group, and soybean seeds (Zhoudou No. 11) were planted in 9 soybean test plots, with a row spacing of 50 cm and a plant spacing of 12.5 cm. The soybean plants (60 days) and soybean yield were statistically analyzed, and the statistical results are shown in the following table:

[0090]

[0091] Referring to the data in the above table, according to the comparison between the implementation group and the blank group of Examples 1-3 and Comparative Examples 1-5, it can be known that the microbial fertilizer containing the composite biological agent of the present application has a significant effect of increasing production and volume.

[0092] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0093] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined in this application, they shall all fall within the protection scope of the present invention.

Claims

1. A microbial fertilizer containing a composite biological agent, characterized in that: It comprises the following components in parts by weight: 25-30 parts of corn stalks, 6-12 parts of dry cow dung, 3-9 parts of fungus bran, 5-11 parts of compound fertilizer, 2-12 parts of compound biological agent, 4-6 parts of light calcium carbonate, 1-3 parts of humic acid, 4-10 parts of earthworm castings, 3-5 parts of sodium alginate, 2-3 parts of chitosan, 20-30 parts of acetic acid solution and 15-20 parts of calcium chloride solution; Wherein, the composite biological agent is prepared by the following steps: Step s1: the cotton straw segments and urea are mixed evenly, and then placed in a tubular furnace, heated to 500-520°C at a heating rate of 8-10°C / min, and then calcined at a constant temperature for 2-3h, and then cooled with the furnace to obtain nitrogen-doped biochar; Step s2: Add nitrogen-doped biochar, potassium hydroxide and deionized water into a three-necked flask equipped with a stirrer and a thermometer, stir and react for 20-30 minutes at a temperature of 20-25°C and a stirring rate of 300-400r / min, then heat to 70-75°C and continue stirring and reacting for 8-10 hours. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water for 2-3 times, then place it in a vacuum drying oven, and dry it at a temperature of 60-65°C for 2-3 hours to obtain expanded pore nitrogen-doped biochar; Step s3: Add the composite bacterial agent and deionized water into a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introduce nitrogen protection, stir and react for 20-30 minutes at a temperature of 20-25°C and a stirring rate of 300-400r / min, then add the expanded nitrogen-doped biochar and continue stirring and reacting for 30-40 minutes, then freeze-dry to obtain a composite biological bacterial agent.

2. The microbial fertilizer containing a composite biological agent according to claim 1, characterized in that: The usage ratio of the cotton stalk segment and urea in step s1 is 5g:0.5-1.5g; the length of the cotton stalk segment is 1-2cm.

3. The microbial fertilizer containing a composite biological agent according to claim 1, characterized in that: The dosage ratio of the nitrogen-doped biochar, potassium hydroxide and deionized water in step s2 is 10g:7-15g:100-110mL.

4. The microbial fertilizer containing a composite biological agent according to claim 1, characterized in that: The dosage ratio of the composite bacterial agent, deionized water and pore-expanded nitrogen-doped biochar in step s3 is 0.1-0.7 g: 30-35 mL: 5 g.

5. The microbial fertilizer containing a composite biological agent according to claim 4, characterized in that: The composite bacterial agent is obtained by mixing nitrogen-fixing bacteria, potassium-solubilizing bacteria and phosphate-solubilizing bacteria in a mass ratio of 4-6:1-3:1-3.

6. The microbial fertilizer containing a composite biological agent according to claim 5, characterized in that: The number of viable bacteria in the nitrogen-fixing bacteria is ≥ 2×10 10 cfu / g; the number of viable bacteria in the potassium-dissolving bacteria is ≥ 1×10 10 cfu / g; the number of viable bacteria in the phosphate-solubilizing bacteria is ≥ 1×10 10 cfu / g.

7. The microbial fertilizer containing a composite biological agent according to claim 5, characterized in that: The nitrogen-fixing bacteria is one of stem nodule nitrogen-fixing rhizobium and brasiliensis.

8. The microbial fertilizer containing a composite biological agent according to claim 5, characterized in that: The potassium-dissolving bacteria is one of Bacillus colloids and Bacillus circulans.

9. The microbial fertilizer containing a composite biological agent according to claim 5, characterized in that: The phosphate-solubilizing bacteria is one of Bacillus megaterium and Pseudomonas.

10. A method for preparing a microbial fertilizer containing a composite biological agent, characterized in that: The following steps are involved: Step 1: Weigh 25-30 parts of corn stalks, 6-12 parts of dry cow dung, 3-9 parts of fungus bran, 5-11 parts of compound fertilizer, 2-12 parts of compound biological agent, 4-6 parts of light calcium carbonate, 1-3 parts of humic acid, 4-10 parts of earthworm castings, 3-5 parts of sodium alginate, 2-3 parts of chitosan, 20-30 parts of acetic acid solution and 15-20 parts of calcium chloride solution according to weight; Step 2: Add corn stalks, dry cow dung, fungus bran, compound fertilizer, compound biological agent, light calcium carbonate, humic acid and earthworm manure into a mixer, stir and mix for 30-50 minutes at a temperature of 20-25° C. and a stirring rate of 300-400 r / min, and then granulate in a granulator to obtain composite particles with a particle size of 2-3 mm; Step 3: Add sodium alginate, chitosan, acetic acid solution and calcium chloride solution into a mixer, stir and mix for 1-1.5 hours at a temperature of 40-45°C and a stirring rate of 300-400 r / min, and then cool to room temperature to obtain a coating solution; Step 4: Put the composite particles into a fluidized bed coating machine, spray the coating liquid on the rolling composite particles, and then ventilate and dry them to obtain a microbial fertilizer containing a composite biological agent.

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