Efficient microbial compound fertilizer and preparation method thereof

Abstract

The invention relates to the technical field of microbial compound fertilizers, and discloses a high-efficiency microbial compound fertilizer and a preparation method thereof, the high-efficiency microbial compound fertilizer comprises the following raw materials by mass: 20-25 parts of urea, 10-15 parts of monoammonium phosphate, 5-8 parts of diammonium phosphate, 10-15 parts of potassium dihydrogen sulfate, 5-10 parts of potassium sulfate, 5-7 parts of a calcium magnesium phosphate fertilizer, 10-15 parts of a microbial component, and 2-5 parts of a composite filler. The composite filler enhances the adsorption and slow release effects on nutrient components in the fertilizer and reduces nutrient loss of the fertilizer, and the composite filler can be used as a carrier of microbial strains to prevent the microbial strains from being easily influenced by soil temperature, humidity and pH value, so that the activity of the microbial strains is inhibited, and the effect of the compound fertilizer is influenced.

Description

Technical Field

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

[0002] Microbial fertilizer, also known as biological fertilizer, inoculant or bacterial fertilizer, refers to a type of fertilizer product that takes the life activities of microorganisms as the core to enable crops to obtain specific fertilizer effects. Microbial compound fertilizer belongs to the category of compound fertilizer, including a combination of multiple microorganisms, a combination of beneficial microorganisms and different additives, etc. The additives include organic matter (livestock and poultry manure, leather charcoal, lignite, etc.), inorganic matter (fertilizers, trace elements) and other composite products of multiple additives.

[0003] Microbial fertilizers have large losses of nutrients such as nitrogen, phosphorus, and potassium, and low fertilizer microbial activity, resulting in low utilization rate of microbial fertilizers. In addition, the microbial strains in microbial fertilizers are easily affected by soil temperature, humidity, and pH, which inhibits the activity of the microbial strains, thereby affecting the effect of compound fertilizers. Adding sepiolite to microbial fertilizers can effectively absorb beneficial components such as nitrogen, phosphorus, and potassium, and reduce fertilizer loss. However, sepiolite has defects such as low surface acidity and small channels, which affect the quality of microbial fertilizers. Summary of the Invention

[0004] The present invention provides a high-efficiency microbial compound fertilizer and a preparation method thereof, which solves the problems that beneficial components in the microbial compound fertilizer are easily lost and the activity of microbial strains is inhibited.

[0005] The technical solution of the present invention: A high-efficiency microbial compound fertilizer comprises the following raw materials in parts by weight: 20-25 parts of urea, 10-15 parts of monoammonium phosphate, 5-8 parts of diammonium phosphate, 10-15 parts of potassium dihydrogen sulfate, 5-10 parts of potassium sulfate, 5-7 parts of calcium magnesium phosphate, 10-15 parts of microbial components, and 2-5 parts of composite fillers; A method for preparing a high-efficiency microbial compound fertilizer comprises the following steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer was mixed and stirred at 60-80r / min for 5-10min to obtain a mixture; S2. The microbial components, composite fillers and mixed materials are mixed, stirred at 60-80 r / min for 5-10 minutes, granulated, dried at 65-75° C. for 20-30 minutes, screened, and packaged to obtain a microbial compound fertilizer.

[0006] The composite filler is obtained by mixing modified sepiolite, hydroxypropyl methylcellulose, ferric chloride and tea polyphenols and then freeze-drying. The modified sepiolite is prepared by in-situ synthesis of porous biochar on the surface of hydrothermally treated sepiolite, followed by reaction with magnesium chloride hexahydrate and sodium hydroxide. The microbial components are fermented by composite bacteria to form fermentation liquid, which is then mixed with organic powder and dried and dispersed.

[0007] Furthermore, the composite filler is specifically prepared by the following steps: A1. The sepiolite and deionized water were mixed and stirred, maintaining a pressure of 1-1.5MPa, and hydrothermally treated at 150-200 ℃ for 3-7h, cooled to room temperature, filtered, washed, and dried to obtain pretreated sepiolite; A2. The pretreated sepiolite, corn straw, and tannic acid were added to deionized water, stirred, filtered, washed, dried, and potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 750-850 ° C for 3-5h, cooled to room temperature, filtered, washed, and dried to obtain a porous carbon-loaded sepiolite. A3. The porous carbon-loaded sepiolite and magnesium chloride hexahydrate solution were mixed and stirred, sodium hydroxide was added, stirred, filtered, washed, dried, calcined at 450-550 ℃ for 4-6h, and cooled to room temperature to obtain a modified sepiolite; A4. Add hydroxypropyl methylcellulose and modified sepiolite to deionized water and stir evenly. Add tea polyphenols and ferric chloride and stir until gel-like. Wash the gel and freeze-dry to obtain a composite filler.

[0008] Furthermore, during the above reaction A1, the sepiolite is hydrothermally treated at 150-200° C., which can remove adsorbed water in the sepiolite, decompose organic impurities, expand the pore size of the sepiolite and increase the porosity, thereby obtaining pretreated sepiolite.

[0009] Furthermore, in the above-mentioned A2 reaction process, tannic acid is used as an adhesive, so that the corn straw adheres to the surface of the pretreated sepiolite through the tannic acid. After high-temperature carbonization, the corn straw is thermally decomposed to form a dense carbon layer. Potassium hydroxide solution is used as an activator to form pores on the surface of the dense carbon layer, thereby realizing the synthesis of porous biocarbon on the surface of the pretreated sepiolite. The pore diameter of the porous biocarbon is 100-200nm and the particle size is 3-5μm, thereby obtaining sepiolite loaded with porous carbon.

[0010] Furthermore, during the above-mentioned reaction A3, the porous carbon-loaded sepiolite has high adsorption performance and a large pore size, and can adsorb magnesium chloride hexahydrate into the pores on the surface of the modified sepiolite. The magnesium ions in the magnesium chloride hexahydrate can react with sodium hydroxide to form hydroxides in the pores of the modified sepiolite. After high-temperature calcination, the hydroxides are thermally decomposed to form oxide crystals, and the crystals grow, thereby synthesizing nano-magnesium oxide with a size of 20-50 nm in the pores on the surface of the modified sepiolite, thereby obtaining the modified sepiolite.

[0011] Furthermore, in the above-mentioned A4 reaction process, ferric chloride, as a cross-linking agent, can combine with the oxygen-containing functional groups contained in hydroxypropyl methylcellulose through strong hydrogen bonds, and form a hydrogen bond network with the phenolic hydroxyl groups of tea polyphenols, thereby forming a three-dimensional cross-linked network structure. The modified sepiolite can also be embedded in the cross-linked network structure, thereby forming a composite aerogel structure with a three-dimensional network structure as a composite filler.

[0012] Furthermore, in step A1, the ratio of the sepiolite to deionized water is (4-6) g: (70-80) mL.

[0013] Furthermore, in step A2, the ratio of the pretreated sepiolite, corn straw, tannic acid, deionized water and potassium hydroxide solution is (3.5-3.8) g: (1.5-2) g: (0.1-0.3) g: (90-110) mL: (4.5-5.5) mL.

[0014] Furthermore, in step A3, the ratio of the porous carbon-loaded sepiolite, magnesium chloride hexahydrate solution, and sodium hydroxide is (4-5) g: (45-55) mL: (0.4-0.6) g.

[0015] Furthermore, in step A4, the ratio of hydroxypropyl methylcellulose, modified sepiolite, deionized water, tea polyphenols and ferric chloride is (3.5-4.5) g: (1-2) g: (45-55) mL: (2-2.4) g: (0.1-0.3) g.

[0016] Furthermore, the microbial component is specifically prepared by the following steps: The composite strain is inoculated into the seed culture medium at an inoculation rate of 2-5%, and cultured at 30-32°C and 180-200 rpm for 3-5 days. The fermentation liquid is collected, diluted with clean water, and then mixed with organic powder. After the organic powder fully absorbs the fermentation liquid, it is dried and broken into powder to obtain the microbial component.

[0017] Furthermore, the seed culture medium formula is: glucose 15-20 g / L, amino acid 8-10 g / L, magnesium sulfate 0.4-0.5 g / L, potassium dihydrogen phosphate 0.4-0.5 g / L, and the culture medium pH value is 7.0-7.2.

[0018] Furthermore, the organic powder is selected from any one of sawdust, bran and straw.

[0019] Furthermore, the composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of (5-10):(5-10):(1-3).

[0020] The present invention has the following beneficial effects: (1) In the technical solution of the present invention, sepiolite is subjected to hydrothermal treatment to remove adsorbed water in the sepiolite, decompose organic impurities, expand the pore size of the sepiolite and increase the porosity, thereby improving the adsorption performance of the sepiolite, thereby enhancing the adsorption of nutrients in the fertilizer and reducing nutrient loss in the fertilizer.

[0021] (2) In the technical solution of the present invention, porous biochar is synthesized on the surface of pretreated sepiolite. On the one hand, the synthesized porous biochar contains a rich pore structure, which is compounded with pretreated sepiolite to improve the adsorption of nutrients in fertilizers and further reduce the nutrient loss of fertilizers. The layered silicate structure of pretreated sepiolite has high mechanical strength, which avoids the structural brittleness of porous biochar caused by high porosity. On the other hand, the porous structure of biochar has a physical adsorption effect on organic pollutants (such as heavy metals), and the silicon hydroxyl groups on the surface of pretreated sepiolite can enhance the adsorption of heavy metals through coordination and complexation, reduce the pollution of heavy metals to the soil, and improve soil fertility. In addition, pretreated sepiolite and porous biochar can adsorb nutrient ions such as potassium, calcium, and magnesium in fertilizers and release them slowly, thereby improving the soil's fertilizer retention capacity.

[0022] (3) In the technical solution of the present invention, nano-magnesium oxide is synthesized in the pores on the surface of the modified sepiolite. On the one hand, the synthesized nano-magnesium oxide provides a large amount of magnesium element, which is one of the medium-amount nutrients necessary for the normal growth and development of plants and can promote the growth of crops. At the same time, magnesium element can alleviate salt stress and improve fertility. On the other hand, nano-magnesium oxide can refine the pore size of the porous biochar in the modified sepiolite, improve the adsorption performance, and further enhance the adsorption and slow release of nutrient components in the fertilizer. Nano-magnesium oxide serves as the skeleton structure of the porous biochar, which prevents the porous biochar and the fertilizer from being subjected to stress during the granulation and screening process, resulting in the collapse of the porous biochar pores and affecting the adsorption of nutrients.

[0023] (4) In the technical solution of the present invention, modified sepiolite, hydroxypropyl methylcellulose, ferric chloride and tea polyphenols are mixed and reacted to form a composite aerogel with a three-dimensional network structure. Hydroxypropyl methylcellulose serves as a skeleton and contains a large number of functional groups, which enhances the water retention performance of the composite filler and has a porous structure, which increases the adsorption of fertilizers. In addition, the formed composite aerogel can be evenly dispersed in the microbial compound fertilizer, thereby improving the fertility of the microbial compound fertilizer.

[0024] (5) In the technical solution of the present invention, the diluted microbial fermentation liquid is added to the organic powder so that the organic matter can fully absorb the microbial fermentation liquid, dry it at low temperature, and break it into powder to obtain the microbial components, thereby avoiding the microbial fermentation liquid from directly penetrating into part of the compound fertilizer and affecting the mixing with other parts of the compound fertilizer, thereby improving the uniformity of the microorganisms, and the composite filler can also serve as a carrier of the microbial strains, thereby avoiding the microbial strains from being easily affected by the soil temperature, humidity, and pH, resulting in the inhibition of the activity of the microbial strains, thereby affecting the effect of the compound fertilizer. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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 making any creative efforts shall fall within the scope of protection of the present invention.

[0026] The raw materials used in the examples of the present invention are as follows, and all reagents used are of analytical grade.

[0027] Among them, Bacillus subtilis (Accc 60429), Bacillus megaterium (CICC 20665), and Azotobacter chroococcum (CICC 22661) were all purchased from the China Industrial Microbiology Culture Collection Center.

[0028] Sepiolite with a particle size of 45 μm was purchased from Lingshou County Yuanda Mica Factory.

[0029] The organic powder is selected from sawdust.

[0030] Example 1 A high-efficiency microbial compound fertilizer, comprising the following raw materials in parts by weight: 20 parts of urea, 10 parts of monoammonium phosphate, 5 parts of diammonium phosphate, 10 parts of potassium dihydrogen sulfate, 5 parts of potassium sulfate, 5 parts of calcium magnesium phosphate fertilizer, 10 parts of microbial components, and 2 parts of composite filler; A method for preparing a high-efficiency microbial compound fertilizer comprises the following steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer were mixed and stirred at 60r / min for 5min to obtain a mixture; S2. The microbial components, composite fillers, and mixed materials are mixed, stirred at 60 rpm for 5 min, granulated, dried at 65° C. for 20 min, screened, and packaged to obtain a microbial compound fertilizer.

[0031] The composite filler is specifically prepared by the following steps: A1. 4 g of sepiolite and 70 mL of deionized water were mixed and stirred, maintaining a pressure of 1 MPa, and hydrothermally treated at 150 ° C for 3 h, cooled to room temperature, filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain pretreated sepiolite; A2. 3.5 g of pretreated sepiolite, 1.5 g of corn straw, and 0.1 g of tannic acid were added to 90 mL of deionized water and stirred at 75°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 4.5 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 750°C for 3 h. The mixture was cooled to room temperature, filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain porous carbon-loaded sepiolite. A3. 4 g of porous carbon-loaded sepiolite was mixed with 45 mL of 0.2 mol / L magnesium chloride hexahydrate solution and stirred. 0.4 g of sodium hydroxide was added and stirred at 30 ° C for 30 min. The mixture was filtered, washed three times with deionized water, dried in an oven at 80 ° C for 2 h, placed in a muffle furnace, calcined at 450 ° C for 4 h, and cooled to room temperature to obtain modified sepiolite. A4. Add 3.5 g of hydroxypropyl methylcellulose and 1 g of modified sepiolite to 45 mL of deionized water and stir evenly. Then add 2 g of tea polyphenols and 0.1 g of ferric chloride and stir at 350 rpm until a gel forms. Wash the gel three times with deionized water and freeze-dry at -20°C for 24 h to obtain a composite filler.

[0032] The microbial component is specifically prepared by the following steps: The composite strain was inoculated into the seed culture medium at an inoculation rate of 2%, and cultured at 30°C and 180 rpm for 3 days. The fermentation liquid was collected, diluted 10 times with clean water, and then mixed with sawdust. After the sawdust fully absorbed the fermentation liquid, it was dried at 30°C for 38 minutes and broken into powder to obtain a microbial component, wherein the sawdust content was 25%; The seed culture medium formula is: glucose 15g / L, amino acid 8g / L, magnesium sulfate 0.4g / L, potassium dihydrogen phosphate 0.4g / L, and the culture medium pH value is 7.0.

[0033] The composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of 5:5:1.

[0034] Example 2 A high-efficiency microbial compound fertilizer, comprising the following raw materials in parts by weight: 23 parts of urea, 13 parts of monoammonium phosphate, 7 parts of diammonium phosphate, 13 parts of potassium dihydrogen sulfate, 8 parts of potassium sulfate, 6 parts of calcium magnesium phosphate, 13 parts of microbial components, and 4 parts of composite fillers; A method for preparing a high-efficiency microbial compound fertilizer comprises the following steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer were mixed and stirred at 70r / min for 8min to obtain a mixture; S2. The microbial components, composite filler and mixed material are mixed, stirred at 70 r / min for 8 minutes, granulated, dried at 70° C. for 25 minutes, screened, and packaged to obtain a microbial compound fertilizer.

[0035] The composite filler is specifically prepared by the following steps: A1. 5 g of sepiolite and 75 mL of deionized water were mixed and stirred, maintaining a pressure of 1.3 MPa, and hydrothermally treated at 180 ° C for 5 h, cooled to room temperature, filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain pretreated sepiolite; A2. 3.7 g of pretreated sepiolite, 1.8 g of corn straw, and 0.2 g of tannic acid were added to 100 mL of deionized water and stirred at 75°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 5 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 800°C for 4 h. The mixture was cooled to room temperature, filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain porous carbon-loaded sepiolite. A3. 4.5 g of porous carbon-loaded sepiolite was mixed with 50 mL of 0.2 mol / L magnesium chloride hexahydrate solution and stirred uniformly. 0.5 g of sodium hydroxide was added and stirred at 30 ° C for 30 min. The mixture was filtered, washed three times with deionized water, dried in an oven at 80 ° C for 2 h, placed in a muffle furnace, calcined at 500 ° C for 5 h, and cooled to room temperature to obtain modified sepiolite. A4. Add 4 g of hydroxypropyl methylcellulose and 1.5 g of modified sepiolite to 50 mL of deionized water and stir evenly. Then add 2.2 g of tea polyphenols and 0.2 g of ferric chloride and stir at 350 rpm until a gel forms. Wash the gel three times with deionized water and freeze-dry at -20°C for 24 h to obtain a composite filler.

[0036] The microbial component is specifically prepared by the following steps: The composite strain was inoculated into a seed culture medium at an inoculum size of 3%, and cultured at 31°C and 190 rpm for 4 days. The fermentation broth was collected, diluted 10-fold with clean water, and then mixed with sawdust. After the sawdust fully absorbed the fermentation broth, it was dried at 30°C for 38 minutes and powdered to obtain a microbial component, wherein the organic matter powder content was 25%. The seed culture medium formula is: glucose 18g / L, amino acid 9g / L, magnesium sulfate 0.45g / L, potassium dihydrogen phosphate 0.45g / L, and the culture medium pH value is 7.1.

[0037] The composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of 8:8:2.

[0038] Example 3 A high-efficiency microbial compound fertilizer, comprising the following raw materials in parts by weight: 25 parts of urea, 15 parts of monoammonium phosphate, 8 parts of diammonium phosphate, 15 parts of potassium dihydrogen sulfate, 10 parts of potassium sulfate, 7 parts of calcium magnesium phosphate, 15 parts of microbial components, and 5 parts of composite fillers; A method for preparing a high-efficiency microbial compound fertilizer comprises the following steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer were mixed and stirred at 80r / min for 10min to obtain a mixture; S2. The microbial components, composite fillers and mixed materials are mixed, stirred at 80 r / min for 10 min, granulated, dried at 75° C. for 30 min, screened, and packaged to obtain a microbial compound fertilizer.

[0039] The composite filler is specifically prepared by the following steps: A1. 6 g of sepiolite and 80 mL of deionized water were mixed and stirred, maintaining a pressure of 1.5 MPa, maintaining a pressure of 1.5 MPa, and hydrothermally treated at 200 ° C for 7 h, cooled to room temperature, filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain pretreated sepiolite; A2. 3.8 g of pretreated sepiolite, 2 g of corn straw, and 0.3 g of tannic acid were added to 110 mL of deionized water and stirred at 75°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 5.5 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 850°C for 5 h. The mixture was cooled to room temperature, filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain porous carbon-loaded sepiolite. A3. 5 g of porous carbon-loaded sepiolite was mixed with 55 mL of 0.2 mol / L magnesium chloride hexahydrate solution and stirred uniformly. 0.6 g of sodium hydroxide was added and stirred at 30 ° C for 30 min. The mixture was filtered, washed three times with deionized water, dried in an oven at 80 ° C for 2 h, placed in a muffle furnace, calcined at 550 ° C for 6 h, and cooled to room temperature to obtain modified sepiolite. A4. Add 4.5 g of hydroxypropyl methylcellulose and 2 g of modified sepiolite to 55 mL of deionized water and stir evenly. Then add 2.4 g of tea polyphenols and 0.3 g of ferric chloride and stir at 350 rpm until a gel forms. Wash the gel three times with deionized water and freeze-dry at -20°C for 24 h to obtain a composite filler.

[0040] The microbial component is specifically prepared by the following steps: The composite strain was inoculated into the seed culture medium at an inoculum size of 5%, and cultured at 32°C and 200 rpm for 5 days. The fermentation broth was collected, diluted 10 times with clean water, and then mixed with sawdust. After the sawdust fully absorbed the fermentation broth, it was dried at 30°C for 38 minutes and powdered to obtain a microbial component, wherein the organic matter powder content was 25%; The seed culture medium formula is: glucose 20g / L, amino acid 10g / L, magnesium sulfate 0.5g / L, potassium dihydrogen phosphate 0.5g / L, and the culture medium pH value is 7.2.

[0041] The composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of 10:10:3.

[0042] Comparative Example 1 A high-efficiency microbial compound fertilizer, comprising the following raw materials in parts by weight: 25 parts of urea, 15 parts of monoammonium phosphate, 8 parts of diammonium phosphate, 15 parts of potassium dihydrogen sulfate, 10 parts of potassium sulfate, 7 parts of calcium magnesium phosphate, 15 parts of microbial components, and 5 parts of composite fillers; A method for preparing a high-efficiency microbial compound fertilizer comprises the following steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer were mixed and stirred at 80r / min for 10min to obtain a mixture; S2. The microbial components, composite fillers and mixed materials are mixed, stirred at 80 r / min for 10 min, granulated, dried at 75° C. for 30 min, screened, and packaged to obtain a microbial compound fertilizer.

[0043] The composite filler is specifically prepared by the following steps: A1. 3.8 g of pretreated sepiolite, 2 g of corn straw, and 0.3 g of tannic acid were added to 110 mL of deionized water and stirred at 75°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 5.5 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 850°C for 5 h. The mixture was cooled to room temperature, filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain porous carbon-loaded sepiolite. A2. 5 g of porous carbon-loaded sepiolite was mixed with 55 mL of 0.2 mol / L magnesium chloride hexahydrate solution and stirred uniformly. 0.6 g of sodium hydroxide was added and stirred at 30 ° C for 30 min. The mixture was filtered, washed three times with deionized water, dried in an oven at 80 ° C for 2 h, placed in a muffle furnace, calcined at 550 ° C for 6 h, and cooled to room temperature to obtain modified sepiolite. A3. Add 4.5 g of hydroxypropyl methylcellulose and 2 g of modified sepiolite to 55 mL of deionized water and stir evenly. Then add 2.4 g of tea polyphenols and 0.3 g of ferric chloride and stir at 350 rpm until a gel forms. Wash the gel three times with deionized water and freeze-dry at -20°C for 24 h to obtain a composite filler.

[0044] The microbial component is specifically prepared by the following steps: The composite strain was inoculated into the seed culture medium at an inoculum size of 5%, and cultured at 32°C and 200 rpm for 5 days. The fermentation broth was collected, diluted 10 times with clean water, and then mixed with sawdust. After the sawdust fully absorbed the fermentation broth, it was dried at 30°C for 38 minutes and powdered to obtain a microbial component, wherein the organic matter powder content was 25%; The seed culture medium formula is: glucose 20g / L, amino acid 10g / L, magnesium sulfate 0.5g / L, potassium dihydrogen phosphate 0.5g / L, and the culture medium pH value is 7.2.

[0045] The composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of 10:10:3.

[0046] Comparative Example 2 A high-efficiency microbial compound fertilizer, comprising the following raw materials in parts by weight: 25 parts of urea, 15 parts of monoammonium phosphate, 8 parts of diammonium phosphate, 15 parts of potassium dihydrogen sulfate, 10 parts of potassium sulfate, 7 parts of calcium magnesium phosphate, 15 parts of microbial components, and 5 parts of composite fillers; A method for preparing a high-efficiency microbial compound fertilizer comprises the following steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer were mixed and stirred at 80r / min for 10min to obtain a mixture; S2. The microbial components, composite fillers and mixed materials are mixed, stirred at 80 r / min for 10 min, granulated, dried at 75° C. for 30 min, screened, and packaged to obtain a microbial compound fertilizer.

[0047] The composite filler is specifically prepared by the following steps: A1. 6 g of sepiolite and 80 mL of deionized water were mixed and stirred, maintaining a pressure of 1.5 MPa, and hydrothermally treated at 200 ° C for 7 h, cooled to room temperature, filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain pretreated sepiolite; A2. 5 g of pretreated sepiolite and 55 mL of 0.2 mol / L magnesium chloride hexahydrate solution were mixed and stirred uniformly. 0.6 g of sodium hydroxide was added and stirred at 30 ° C for 30 min. The mixture was filtered, washed three times with deionized water, dried in an oven at 80 ° C for 2 h, placed in a muffle furnace, calcined at 550 ° C for 6 h, and cooled to room temperature to obtain modified sepiolite. A3. Add 4.5 g of hydroxypropyl methylcellulose and 2 g of modified sepiolite to 55 mL of deionized water and stir evenly. Then add 2.4 g of tea polyphenols and 0.3 g of ferric chloride and stir at 350 rpm until a gel forms. Wash the gel three times with deionized water and freeze-dry at -20°C for 24 h to obtain a composite filler.

[0048] The microbial component is specifically prepared by the following steps: The composite strain was inoculated into the seed culture medium at an inoculum size of 5%, and cultured at 32°C and 200 rpm for 5 days. The fermentation broth was collected, diluted 10 times with clean water, and then mixed with sawdust. After the sawdust fully absorbed the fermentation broth, it was dried at 30°C for 38 minutes and powdered to obtain a microbial component, wherein the organic matter powder content was 25%; The seed culture medium formula is: glucose 20g / L, amino acid 10g / L, magnesium sulfate 0.5g / L, potassium dihydrogen phosphate 0.5g / L, and the culture medium pH value is 7.2.

[0049] The composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of 10:10:3.

[0050] Comparative Example 3 A high-efficiency microbial compound fertilizer, comprising the following raw materials in parts by weight: 25 parts of urea, 15 parts of monoammonium phosphate, 8 parts of diammonium phosphate, 15 parts of potassium dihydrogen sulfate, 10 parts of potassium sulfate, 7 parts of calcium magnesium phosphate, 15 parts of microbial components, and 5 parts of composite fillers; A method for preparing a high-efficiency microbial compound fertilizer comprises the following steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer were mixed and stirred at 80r / min for 10min to obtain a mixture; S2. The microbial components, composite fillers and mixed materials are mixed, stirred at 80 r / min for 10 min, granulated, dried at 75° C. for 30 min, screened, and packaged to obtain a microbial compound fertilizer.

[0051] The composite filler is specifically prepared by the following steps: A1. 6 g of sepiolite and 80 mL of deionized water were mixed and stirred, maintaining a pressure of 1.5 MPa, and hydrothermally treated at 200 ° C for 7 h, cooled to room temperature, filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain pretreated sepiolite; A2. 3.8 g of pretreated sepiolite, 2 g of corn straw, and 0.3 g of tannic acid were added to 110 mL of deionized water and stirred at 75°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 5.5 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 850°C for 5 h. The mixture was cooled to room temperature, filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain porous carbon-loaded sepiolite. A3. Add 4.5 g of hydroxypropyl methylcellulose and 2 g of porous carbon-loaded sepiolite to 55 mL of deionized water and stir evenly. Then add 2.4 g of tea polyphenols and 0.3 g of ferric chloride and stir at 350 rpm until it forms a gel. Wash the gel three times with deionized water and freeze-dry it at -20°C for 24 h to obtain a composite filler.

[0052] The microbial component is specifically prepared by the following steps: The composite strain was inoculated into the seed culture medium at an inoculum size of 5%, and cultured at 32°C and 200 rpm for 5 days. The fermentation broth was collected, diluted 10 times with clean water, and then mixed with sawdust. After the sawdust fully absorbed the fermentation broth, it was dried at 30°C for 38 minutes and powdered to obtain a microbial component, wherein the organic matter powder content was 25%; The seed culture medium formula is: glucose 20g / L, amino acid 10g / L, magnesium sulfate 0.5g / L, potassium dihydrogen phosphate 0.5g / L, and the culture medium pH value is 7.2.

[0053] The composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of 10:10:3.

[0054] Comparative Example 4 A high-efficiency microbial compound fertilizer, comprising the following raw materials in parts by weight: 25 parts of urea, 15 parts of monoammonium phosphate, 8 parts of diammonium phosphate, 15 parts of potassium dihydrogen sulfate, 10 parts of potassium sulfate, 7 parts of calcium magnesium phosphate, 15 parts of microbial components, and 5 parts of composite fillers; A method for preparing a high-efficiency microbial compound fertilizer comprises the following steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer were mixed and stirred at 80r / min for 10min to obtain a mixture; S2. The microbial components, composite fillers and mixed materials are mixed, stirred at 80 r / min for 10 min, granulated, dried at 75° C. for 30 min, screened, and packaged to obtain a microbial compound fertilizer.

[0055] The composite filler is specifically prepared by the following steps: A1. 6 g of sepiolite and 80 mL of deionized water were mixed and stirred, maintaining a pressure of 1.5 MPa, and hydrothermally treated at 200 ° C for 7 h, cooled to room temperature, filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain pretreated sepiolite; A2. 3.8 g of pretreated sepiolite, 2 g of corn straw, and 0.3 g of tannic acid were added to 110 mL of deionized water and stirred at 75°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 5.5 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 850°C for 5 h. The mixture was cooled to room temperature, filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain porous carbon-loaded sepiolite. A3. 5 g of porous carbon-loaded sepiolite was mixed with 55 mL of 0.2 mol / L magnesium chloride hexahydrate solution and stirred uniformly. 0.6 g of sodium hydroxide was added and stirred at 30 ° C for 30 min. The mixture was filtered, washed three times with deionized water, dried in an oven at 80 ° C for 2 h, placed in a muffle furnace, calcined at 550 ° C for 6 h, and cooled to room temperature to obtain modified sepiolite. A4. Add 6.9 g of tea polyphenols and 2 g of modified sepiolite to 55 mL of deionized water and stir evenly. Add 0.3 g of ferric chloride and stir evenly at 350 r / min. Wash three times with deionized water and freeze-dry at -20°C for 24 h to obtain a composite filler.

[0056] The microbial component is specifically prepared by the following steps: The composite strain was inoculated into the seed culture medium at an inoculum size of 5%, and cultured at 32°C and 200 rpm for 5 days. The fermentation broth was collected, diluted 10 times with clean water, and then mixed with sawdust. After the sawdust fully absorbed the fermentation broth, it was dried at 30°C for 38 minutes and powdered to obtain a microbial component, wherein the organic matter powder content was 25%; The seed culture medium formula is: glucose 20g / L, amino acid 10g / L, magnesium sulfate 0.5g / L, potassium dihydrogen phosphate 0.5g / L, and the culture medium pH value is 7.2.

[0057] The composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of 10:10:3.

[0058] Comparative Example 5 A high-efficiency microbial compound fertilizer, comprising the following raw materials in parts by weight: 25 parts of urea, 15 parts of monoammonium phosphate, 8 parts of diammonium phosphate, 15 parts of potassium dihydrogen sulfate, 10 parts of potassium sulfate, 7 parts of calcium magnesium phosphate, 15 parts of microbial components, and 5 parts of composite fillers; A method for preparing a high-efficiency microbial compound fertilizer comprises the following steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer were mixed and stirred at 80r / min for 10min to obtain a mixture; S2. The microbial components, composite fillers and mixed materials are mixed, stirred at 80 r / min for 10 min, granulated, dried at 75° C. for 30 min, screened, and packaged to obtain a microbial compound fertilizer.

[0059] The composite filler is specifically prepared by the following steps: A1. 6 g of sepiolite and 80 mL of deionized water were mixed and stirred, maintaining a pressure of 1.5 MPa, and hydrothermally treated at 200 ° C for 7 h, cooled to room temperature, filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain pretreated sepiolite; A2. 3.8 g of pretreated sepiolite, 2 g of corn straw, and 0.3 g of tannic acid were added to 110 mL of deionized water and stirred at 75°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 5.5 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 850°C for 5 h. The mixture was cooled to room temperature, filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain porous carbon-loaded sepiolite. A3. 5 g of porous carbon-loaded sepiolite was mixed with 55 mL of 0.2 mol / L magnesium chloride hexahydrate solution and stirred uniformly. 0.6 g of sodium hydroxide was added and stirred at 30 ° C for 30 min. The mixture was filtered, washed three times with deionized water, dried in an oven at 80 ° C for 2 h, placed in a muffle furnace, calcined at 550 ° C for 6 h, and cooled to room temperature to obtain modified sepiolite. A4. Add 4.5 g of hydroxypropyl methylcellulose and 2 g of modified sepiolite to 55 mL of deionized water and stir evenly. Then add 2.4 g of tea polyphenols and 0.3 g of ferric chloride and stir at 350 rpm until a gel forms. Wash the gel three times with deionized water and freeze-dry at -20°C for 24 h to obtain a composite filler.

[0060] The microbial component is specifically prepared by the following steps: The composite strain was inoculated into a seed culture medium at an inoculation rate of 5%, and cultured at 32°C and 200 rpm for 5 days. The fermentation broth was collected, diluted 10 times with clean water, and then evenly mixed with urea. The mixture was dried at 30°C for 38 minutes and powdered to obtain a microbial component, wherein the urea content was 25%. The seed culture medium formula is: glucose 20g / L, amino acid 10g / L, magnesium sulfate 0.5g / L, potassium dihydrogen phosphate 0.5g / L, and the culture medium pH value is 7.2.

[0061] The composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of 10:10:3.

[0062] The performance of the microbial compound fertilizers prepared in Examples 1-3 and Comparative Examples 1-5 was tested.

[0063] 3 g of compound fertilizer was weighed and mixed evenly with 8 kg of soil, and then placed in flower pots. 20 grains of wheat were sown in each pot, for a total of five pots. After the wheat seedlings emerged, thinning was carried out, and 5 wheat seedlings with uniform growth were retained in each pot. After winter, the pots were buried in the soil to prevent frostbite of the wheat roots. After the wheat was harvested, the whole wheat plant was taken, dried and weighed to obtain the dry matter mass; the nitrogen content of the wheat plants was determined by Nessler colorimetry, the phosphorus content was determined by vanadium molybdenum yellow colorimetry, and the potassium content was determined by flame photometry.

[0064] The test results are shown in Table 1 below.

[0065] Table 1 Performance test of microbial compound fertilizer prepared in Examples 1-3 and Comparative Examples 1-5

[0066] It can be seen from the data in Table 1 that the microbial compound fertilizers prepared in Examples 1-3 can increase the yield of crops and improve the soil's ability to retain fertilizer.

[0067] In comparative example 1, the pretreated sepiolite was replaced with a composite filler prepared from sepiolite and added to the microbial compound fertilizer. The wheat yield decreased and the nutritional components in the wheat decreased, proving that the hydrothermal treatment of sepiolite removed the adsorbed water in the sepiolite, decomposed the organic impurities, expanded the pore size of the sepiolite and increased the porosity, thereby improving the adsorption performance of the sepiolite, thereby enhancing the adsorption of nutrients in the fertilizer and reducing the nutrient loss of the fertilizer.

[0068] In comparative example 2, the porous carbon-loaded sepiolite was replaced with a composite filler prepared from pretreated sepiolite and added to the microbial compound fertilizer. The wheat yield decreased and the nutritional components in the wheat decreased, proving that the synthesis of porous biochar on the surface of pretreated sepiolite improves the adsorption of nutrients in the fertilizer and further reduces the nutrient loss of the fertilizer. The porous structure of the biochar has a physical adsorption effect on organic pollutants (such as heavy metals), and the silicon hydroxyl groups on the surface of the pretreated sepiolite can enhance the adsorption of heavy metals through coordination and complexation, reduce the pollution of heavy metals to the soil, and improve soil fertility. In addition, the pretreated sepiolite and porous biochar can adsorb nutrient ions such as potassium, calcium, and magnesium in the fertilizer and release them slowly, thereby improving the soil's fertilizer retention capacity.

[0069] In Comparative Example 3, a composite filler prepared by replacing the modified sepiolite with sepiolite loaded with porous carbon was added to the microbial compound fertilizer. The wheat yield decreased and the nutritional components in the wheat decreased, proving that the synthesis of nano-magnesium oxide in the pores on the surface of the modified sepiolite can promote the growth of crops. At the same time, the magnesium element can alleviate salt stress and improve fertility. Nano-magnesium oxide serves as the skeleton structure of porous biochar, preventing the porous biochar and fertilizer from being subjected to stress during the granulation and screening process, resulting in the collapse of the porous biochar pores and affecting the adsorption of nutrients.

[0070] In Comparative Example 4, a composite filler prepared by replacing hydroxypropyl methylcellulose with tea polyphenols was added to the microbial compound fertilizer. The wheat yield decreased and the nutritional components in the wheat decreased, proving that the mixed reaction of modified sepiolite, hydroxypropyl methylcellulose, ferric chloride and tea polyphenols can form a composite aerogel with a three-dimensional network structure. Hydroxypropyl methylcellulose serves as a skeleton and contains a large number of functional groups, which enhances the water retention performance of the composite filler and has a porous structure, which increases the adsorption of fertilizers. In addition, the formed composite aerogel can be evenly dispersed in the microbial compound fertilizer and can serve as a carrier of microbial strains, avoiding the microbial strains from being easily affected by soil temperature, humidity, and pH, resulting in the inhibition of the activity of the microbial strains, thereby affecting the effect of the compound fertilizer and improving the fertility of the microbial compound fertilizer.

[0071] In Comparative Example 5, the microbial components prepared by replacing sawdust with urea were added to the microbial compound fertilizer. The wheat yield decreased and the nutritional components in the wheat decreased. This proves that adding the diluted microbial fermentation liquid to the organic matter powder can prevent the microbial fermentation liquid from directly penetrating into part of the compound fertilizer, affecting the mixing with other parts of the compound fertilizer, and improving the uniformity of the microorganisms.

[0072] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0073] 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 described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A high-efficiency microbial compound fertilizer, characterized in that: The method comprises the following raw materials in parts by weight: 20-25 parts of urea, 10-15 parts of monoammonium phosphate, 5-8 parts of diammonium phosphate, 10-15 parts of potassium dihydrogen sulfate, 5-10 parts of potassium sulfate, 5-7 parts of calcium magnesium phosphate fertilizer, 10-15 parts of microbial components, and 2-5 parts of composite filler; The composite filler is obtained by mixing modified sepiolite, hydroxypropyl methylcellulose, ferric chloride and tea polyphenols and then freeze-drying. The modified sepiolite is prepared by in-situ synthesis of porous biochar on the surface of hydrothermally treated sepiolite, followed by reaction with magnesium chloride hexahydrate and sodium hydroxide. The microbial components are fermented by composite bacteria to form fermentation liquid, which is then mixed with organic powder and dried and dispersed.

2. A high-efficiency microbial compound fertilizer according to claim 1, characterized in that, The composite filler is specifically prepared by the following steps: A1. The sepiolite and deionized water were mixed and stirred, maintaining a pressure of 1-1.5MPa, and hydrothermally treated at 150-200 ℃ for 3-7h, cooled to room temperature, filtered, washed, and dried to obtain pretreated sepiolite; A2. The pretreated sepiolite, corn straw, and tannic acid were added to deionized water, stirred, filtered, washed, dried, and potassium hydroxide solution was added. An inert gas was introduced and carbonized at 750-850 ° C for 3-5h. The mixture was cooled to room temperature, filtered, washed, and dried to obtain a porous carbon-loaded sepiolite. A3. The porous carbon-loaded sepiolite and magnesium chloride hexahydrate solution were mixed and stirred, sodium hydroxide was added, stirred, filtered, washed, dried, calcined at 450-550 ℃ for 4-6h, and cooled to room temperature to obtain a modified sepiolite; A4. Add hydroxypropyl methylcellulose and modified sepiolite to deionized water and stir evenly. Add tea polyphenols and ferric chloride and stir until the mixture forms a gel. Wash the gel and freeze-dry it to obtain a composite filler.

3. A high-efficiency microbial compound fertilizer according to claim 2, characterized in that, In step A1, the ratio of the sepiolite to deionized water is (4-6) g: (70-80) mL.

4. A high-efficiency microbial compound fertilizer according to claim 2, characterized in that, In step A2, the ratio of the pretreated sepiolite, corn straw, tannic acid, deionized water and potassium hydroxide solution is (3.5-3.8) g: (1.5-2) g: (0.1-0.3) g: (90-110) mL: (4.5-5.5) mL.

5. A high-efficiency microbial compound fertilizer according to claim 2, characterized in that, In step A3, the ratio of the porous carbon-loaded sepiolite, magnesium chloride hexahydrate solution, and sodium hydroxide is (4-5) g: (45-55) mL: (0.4-0.6) g.

6. A high-efficiency microbial compound fertilizer according to claim 2, characterized in that, In step A4, the ratio of hydroxypropyl methylcellulose, modified sepiolite, deionized water, tea polyphenols and ferric chloride is (3.5-4.5) g: (1-2) g: (45-55) mL: (2-2.4) g: (0.1-0.3) g.

7. A high-efficiency microbial compound fertilizer according to claim 1, characterized in that, The microbial component is specifically prepared by the following steps: The composite strain is inoculated into the seed culture medium at an inoculation rate of 2-5%, and cultured at 30-32°C and 180-200 rpm for 3-5 days. The fermentation liquid is collected, diluted with clean water, and then mixed with organic powder. After the organic powder fully absorbs the fermentation liquid, it is dried and broken into powder to obtain the microbial component.

8. A high-efficiency microbial compound fertilizer according to claim 7, characterized in that: The seed culture medium formula is: 15-20 g / L of glucose, 8-10 g / L of amino acids, 0.4-0.5 g / L of magnesium sulfate, and 0.4-0.5 g / L of potassium dihydrogen phosphate, and the pH value of the culture medium is 7.0-7.

2.

9. A high-efficiency microbial compound fertilizer according to claim 7, characterized in that: The organic powder is selected from any one of sawdust, bran, and straw; The composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus megaterium and Azotobacter chlorosphaeroides in a live bacterial count ratio of (5-10):(5-10):(1-3).

10. A method for preparing a high-efficiency microbial compound fertilizer according to any one of claims 1 to 9, characterized in that: The method comprises the following preparation steps: S1. The urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen sulfate, potassium sulfate, calcium magnesium phosphate fertilizer was mixed and stirred at 60-80r / min for 5-10min to obtain a mixture; S2. The microbial components, composite fillers and mixed materials are mixed, stirred at 60-80 r / min for 5-10 minutes, granulated, dried at 65-75° C. for 20-30 minutes, screened, and packaged to obtain a microbial compound fertilizer.

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