Preparation method of slow-release carbon-based bio-organic fertilizer

Abstract

The invention relates to a preparation method of a slow-release carbon-based bio-organic fertilizer, and belongs to the technical field of slow-release bio-organic fertilizers. The preparation method of the slow-release type carbon-based bio-organic fertilizer comprises the following steps: preparing microorganism-decomposed fermented organic fertilizer particles after decomposing and fermenting the organic fertilizer by adopting biochar, coating by adopting a coating liquid containing the supported biochar, and the like. The carbon-based bio-organic fertilizer prepared by the preparation method disclosed by the invention has a relatively good slow release effect, can be applied to a saline-alkali soil environment, and can be used for improving saline-alkali soil, promoting crop growth and increasing the yield.

Description

Technical Field

[0001] This invention belongs to the field of slow-release bio-organic fertilizer technology, and relates to a method for preparing slow-release carbon-based bio-organic fertilizer. Background Technology

[0002] In recent years, the research and application of biochar in agriculture have received widespread attention and recognition. Biochar's unique adsorption structure determines its special functions, such as soil improvement and soil environment enhancement. To meet the dual needs of crop vegetative growth and soil improvement, biochar-based fertilizers have emerged. Existing research shows that biochar-based fertilizers include biochar-based organic fertilizers, biochar-based nitrogen fertilizers, and biochar-based compound fertilizers, among which biochar-based organic fertilizers are the most widely used. Biochar organic fertilizer is a long-acting organic base fertilizer prepared by mixing biochar as a carrier with other organic materials used in agricultural and forestry production. Biochar organic fertilizer has many advantages, such as high carbon content, soil improvement, slow-release fertilization, reduction of non-point source pollution, and promotion of agricultural and forestry waste recycling, and has broad application prospects.

[0003] The production processes of biochar-based fertilizers mainly involve various technologies such as adsorption, blending, coating, and mixed granulation. Biochar-based fertilizers primarily achieve a slow-release effect by combining nutrients from chemical fertilizers with biomass through complexation, electrostatic adsorption, and physical pore adsorption, reducing nutrient loss. The slow-release properties of biochar-based fertilizers are mainly influenced by the binding characteristics of key elements such as phosphorus, nitrogen, and potassium with biochar. In addition, their performance depends on several other factors, including the selected raw materials, the fertilizer preparation process, and the final application method. The type of biochar, the production method used, and the ratio of biochar to fertilizer all significantly affect the slow-release characteristics and final efficacy of biochar-based fertilizers, collectively determining their performance in agricultural practice. Summary of the Invention

[0004] The main objective of this invention is to provide a method for preparing a slow-release carbon-based bio-organic fertilizer. The carbon-based bio-organic fertilizer prepared by this method has a good slow-release effect and can be used for saline-alkali land improvement to promote crop growth.

[0005] The present invention employs the following technical solutions to achieve the above objectives: A method for preparing a slow-release carbon-based bio-organic fertilizer mainly includes the following steps: I. Preparation of biochar powder and supported biochar: Step 1: Mix wheat straw and peanut shells in a mass ratio of (2.5):1, crush and dry them to obtain the pretreated product; Step 2: Heat the pretreated product to 450-550℃ in an anaerobic environment at a rate of 15-20℃ / min and keep it at that temperature for 1-2 hours for pyrolysis. Step 3: After pyrolysis, the material is cooled and ground to obtain biochar powder. The biochar powder is used in two parts: one is to prepare supported biochar, and the other is to prepare composted and fermented organic fertilizer. Step 4: Mix biochar powder, shiitake mushroom residue powder and 1 mol / L phosphoric acid solution at a mass ratio of 1:(0.3-0.5):5, stir at 80℃ for 2 hours, filter, and set aside filter residue I and filtrate; add ammonium molybdate and boric acid to the filtrate, then add filter residue I, sonicate, filter, and dry filter residue II to obtain supported biochar.

[0006] II. Preparation of well-rotted and fermented organic fertilizer: Step 5: Mix biochar powder, treated chicken manure, and wheat bran in a mass ratio of 1:(0.7-1):0.3, adjust the moisture content to 60%, and obtain mixed organic fertilizer; inoculate with Javan Rhizopus liquid, and aerobic ferment at 25-28℃ for 2-3 days, then aerobic compost fermentation to 55-60℃ and maintain for 2 days, then cool to room temperature to obtain mature fermented organic fertilizer; then inoculate with Candida virescens liquid, and aerobic fermentation at 25-28℃ for 3-4 days, then aerobic compost fermentation and raise the temperature to 65-70℃ and maintain for 2 days; Step 6: After fermentation is complete, dry and crush to obtain well-rotted fermented organic fertilizer.

[0007] III. Microbial-fermented organic fertilizer granules: Step 7: Mix the well-rotted and fermented organic fertilizer and ferrous sulfate evenly to obtain a mixture; add water to the modified starch and spray it onto the mixture, dry it, then spray in the compound microbial agent suspension, and dry it to obtain the mixture. Step 8: Feed the mixture into a granulator, spray a small amount of water as a binder, and form granules; Step 9: Dry the granules until the moisture content is <15% to obtain microbial-fermented organic fertilizer granules.

[0008] IV. Preparation and coating of sustained-release membrane: Step 10: Add sodium alginate and the above-mentioned supported biochar to water and stir evenly to form a mixed coating solution; Step 11: Spray the mixed coating liquid onto the surface of the microbial-fermented organic fertilizer granules using a spray method, and then spray a 4% calcium chloride solution. Dry the coated granules until the moisture content is <10% to obtain coated granules.

[0009] V. Aging and Packaging: Step 12: Aged the coated granules at room temperature for 24 hours to allow the coating to fully solidify, and then packaged to obtain slow-release carbon-based bio-organic fertilizer.

[0010] Preferably, in step 4, the amount of ammonium molybdate added is 10-12 g / L and the amount of boric acid added is 5-8 g / L.

[0011] Preferably, in step 5, the inoculation amount of Java Rhizopus liquid is 5% of the weight of the mixed organic fertilizer; and the inoculation amount of Candida viviparus liquid is 10% of the weight of the mixed organic fertilizer.

[0012] Preferably, in step 7, the mass ratio of fermented organic fertilizer, ferrous sulfate, modified starch, and water is 40:3:5:10.

[0013] Preferably, the modified starch in step 7 is prepared by: Add 100g corn starch and 30g humic acid to 300g deionized water, stir well, heat to 80℃, stir until the starch is completely gelatinized, cool, dry, pulverize, add 100g molten maleic anhydride, stir and react at 80℃ for 2h, cool, wash with anhydrous ethanol, dry to obtain the initial product; dissolve 100g of the initial product in an appropriate amount of water, adjust the pH to 5.0, add 5mL of initiator, after 20min add 20g acrylamide and 10g acryloyloxyethyltrimethylammonium chloride, stir at 80℃ for 2h, cool to room temperature, wash with anhydrous ethanol, dry, pulverize to obtain the modified starch.

[0014] More preferably, the initiator is prepared by dissolving 5g of cerium ammonium nitrate in 100mL of 0.1mol / L nitric acid solution.

[0015] Preferably, the amount of the compound microbial agent suspension used in step 7 is 2-3% of the total dry weight of the material.

[0016] Preferably, the composite microbial agent suspension in step 7 contains Bacillus megaterium solution, Bacillus pumilus solution, and Bacillus subtilis solution in a volume ratio of 1:5:3.

[0017] Preferably, in step 10, the mass ratio of sodium alginate, supported biochar, and water is 3:10:50.

[0018] Preferably, in step 11, the coating weight gain is 5-8% of the particle mass.

[0019] The present invention has the following beneficial effects: In this invention, a slow-release carbon-based bio-organic fertilizer method is used to ferment and produce acid from *Rhizopus javanica* and *Candida virescens* to decompose the organic fertilizer. This effectively reduces the pH of the organic fertilizer during the decomposition process. When used in saline-alkali environments, it can neutralize alkaline components in the soil. Simultaneously, the adsorption and fixation properties of biochar slow down nutrient loss and prolong the fertilizer's effectiveness. The decomposed organic fertilizer is then coated with modified starch to form a slow-release layer. The modified starch effectively isolates any remaining microorganisms in the decomposed organic fertilizer from the sprayed compound microbial agent, preventing antagonistic effects. The modified starch also acts as a cationic adsorbent, absorbing positive ions such as sodium ions in saline-alkali environments, which are effectively decomposed by the compound microorganisms. The outer layer is a coating layer made of sodium alginate and supported biochar. The supported biochar contains acidic substances such as shiitake mushroom residue, ammonium molybdate, and boric acid, which neutralize alkaline components in the soil while providing organic matter and nutrients.

[0020] The slow-release carbon-based bio-organic fertilizer prepared in this invention has a three-layer structure: the outer layer first dissolves and neutralizes alkaline components in saline-alkali soil, provides certain nutrients, and increases water retention. After the outer layer dissolves, the middle layer of microorganisms and modified starch is exposed. The modified starch adsorbs cations, Bacillus megaterium decomposes sodium ions and other components to reduce salinity, Bacillus subtilis secretes organic acids to neutralize alkaline soil, and Bacillus pumilus dissolves phosphorus and fixes nitrogen, all working together to improve the saline-alkali environment. After the middle layer decomposes, the inner layer of acidic organic fertilizer is exposed, further neutralizing alkaline substances and providing organic matter. The porous structure of biochar improves soil aggregate structure and enhances water and fertilizer retention capacity. This slow-release carbon-based bio-organic fertilizer can slowly release nutrients and effectively improve the saline-alkali environment over a long period, providing different nutrients to crops at different stages and promoting crop growth in saline-alkali environments. Attached Figure Description

[0021] Figure 1 Figure 1 shows the tip barrenness of corn in different treatment groups. Figure A shows corn in treatment group 2, Figure B shows corn in treatment group 5, and Figure C shows corn in treatment group 1.

[0022] Figure 2 Comparison of tasseling in maize at the same time point among different treatment groups. Figure D shows maize in treatment group 2, Figure E shows maize in treatment group 5, and Figure F shows maize in treatment group 1. Detailed Implementation

[0023] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope of protection of the claims of this application.

[0024] Example 1 Raw materials and pretreatment Pretreatment of shiitake mushroom residue: Dry the waste shiitake mushroom residue to a moisture content of about 10%, crush it, and pass it through an 80-mesh sieve to obtain shiitake mushroom residue powder for use in the preparation of composted fermented organic fertilizer and supported biochar. Bran: refers to the outermost layer of wheat, with a moisture content of about 10%.

[0025] Chicken manure pretreatment: Place fresh chicken manure in a cool, ventilated place until the moisture content is about 60%. The treated chicken manure is then ready for use. Candida virescens culture: The commercially available Candida virescens (Guangdong Provincial Microbial Culture Collection Center) with the serial number GDMCC NO. 2.183 was activated according to the instructions and cultured until the OD value was about 0.8 to obtain Candida virescens culture for later use; Java Rhizopus solution: After activating the commercially available Java Rhizopus (Guangdong Provincial Microbial Culture Collection Center) with the serial number GDMCC NO. 3.120 according to the instructions, expand the culture to a spore count of about 2 billion / mL to obtain Java Rhizopus solution for later use. Modified starch: Add 100g corn starch and 30g humic acid to 300g deionized water, stir evenly, heat to 80℃, stir until the starch is completely gelatinized, cool, dry, pulverize, add 100g molten maleic anhydride, stir and react at 80℃ for 2h, cool, wash with anhydrous ethanol, dry to obtain the initial product; Dissolve 100g of the initial product in an appropriate amount of water, adjust the pH to 5.0, add 5mL of initiator (prepared by dissolving 5g cerium ammonium nitrate in 100mL of 0.1mol / L nitric acid solution), after 20min, add 20g acrylamide and 10g acryloyloxyethyltrimethylammonium chloride, stir at 80℃ for 2h, cool to room temperature, wash with anhydrous ethanol, dry, pulverize to obtain the modified starch.

[0026] Compound microbial inoculant suspension: After activating the purchased GDMCC NO.1.270 Bacillus megaterium (Guangzhou Provincial Microbial Culture Collection Center) according to the instructions, expand the culture to an effective viable count of approximately 10 × 10⁻⁶. 9 A solution of *Bacillus megaterium* was obtained at approximately CFU / mL. *Bacillus pumilus* (GDMCC NO.1.1736, Guangzhou Provincial Microbial Culture Collection Center) was activated according to the instructions and cultured until the effective viable count reached approximately 8 × 10⁻⁶. 9 The concentration of CFU / mL was approximately equal to that of *Bacillus subtilis*, resulting in a solution of *Bacillus subtilis*. Following the instructions, *Bacillus subtilis* (GDMCC NO.1.254, Guangzhou Provincial Microbial Culture Collection Center) was activated and cultured to a viable count of approximately 10 × 10⁻⁶. 9The concentration of CFU / mL was approximately equal to that of Bacillus subtilis to obtain a solution. The solutions of Bacillus megaterium, Bacillus pumilus, and Bacillus subtilis were then mixed in a volume ratio of 1:5:3 to obtain a compound microbial agent suspension.

[0027] Example 2: Preparation of slow-release carbon-based bio-organic fertilizer I. Preparation of biochar powder and supported biochar: Step 1: Mix 25kg of wheat straw and 10kg of peanut shells, crush them together into pieces with a particle size of 2-3cm, and dry them until the moisture content is ≤10% to obtain the pretreated product; Step 2: Place the pretreated product in a high-temperature pyrolysis furnace, heat it to 550°C at a rate of 20°C / min in an oxygen-free environment, and maintain it at this temperature for 1 hour to carry out complete pyrolysis. Step 3: After pyrolysis, cool to room temperature in an anaerobic environment, remove and crush and grind, then pass through a 100-mesh sieve to obtain biochar powder; part of it is used for composting and fermenting organic fertilizer, and part of it is used to prepare supported biochar. Step 4: Mix 10 kg of the above biochar powder, 3 kg of shiitake mushroom residue powder and 50 kg of 1 mol / L phosphoric acid solution, stir at 80℃ for 2 h, filter, and set aside filter residue I and filtrate; add 12 g / L of ammonium molybdate and 5 g / L of boric acid to the filtrate, then add filter residue I, sonicate for 30 min, filter, and dry filter residue II to obtain supported biochar.

[0028] II. Preparation of well-rotted and fermented organic fertilizer: Step 5: Mix 10 kg of biochar powder, 7 kg of treated chicken manure, and 3 kg of wheat bran, and adjust the overall moisture content to about 60% to obtain mixed organic fertilizer; inoculate with 1 kg of Java Rhizopus liquid, and aerobically ferment at 28℃ for 2 days, then aerobically compost fermentation to a temperature of 55-60℃ and maintain for 2 days, then cool to room temperature to obtain the initial organic fertilizer product; then inoculate with 2 kg of Candida virescens liquid, and aerobically ferment at 28℃ for 3 days, then aerobically compost fermentation and raise the temperature to 65-70℃ and maintain for 2 days; Step 6: After fermentation is complete, dry and crush the material, and pass it through an 80-mesh sieve to obtain well-rotted and fermented organic fertilizer.

[0029] III. Microbial-fermented organic fertilizer granules: Step 7: Thoroughly mix 40 kg of well-rotted and fermented organic fertilizer and 3 kg of ferrous sulfate to obtain a mixture; add 5 kg of modified starch to 10 kg of water and stir evenly, then spray it onto the mixture while stirring to ensure even spraying. After drying, spray in a compound microbial agent suspension (the amount of agent is 3% of the total dry weight of the material) while stirring to ensure even inoculation. After drying, obtain the mixture. Step 8: Feed the mixture into the granulator, spray a small amount of water as a binder, and make spherical granules with a particle size of 3-4 mm. Step 9: Dry the granules at a low temperature below 50℃ with ventilation until the moisture content is <15%, to obtain microbial-fermented organic fertilizer granules.

[0030] IV. Preparation and coating of sustained-release membrane: Step 10: Add 3 kg of sodium alginate and 10 kg of supported biochar powder to 50 kg of water and stir evenly to form a mixed coating solution; Step 11: Place the microbial-fermented organic fertilizer granules in a coating machine. While the machine is in a rolling state, spray the coating liquid evenly onto the surface of the granules using a spraying method. Then spray a 4% calcium chloride solution to coat and solidify the granules. Place the coated granules in a low-temperature dryer and dry them until the moisture content of the granules is <10% (the weight gain of the coating is controlled at 5%-8% of the granule weight).

[0031] V. Aging and Packaging: Step 12: Aged the coated granules at room temperature for 24 hours to allow the coating to fully solidify, and then packaged to obtain slow-release carbon-based bio-organic fertilizer.

[0032] Example 3: Preparation of slow-release carbon-based bio-organic fertilizer I. Preparation of biochar powder and supported biochar: Step 1: Mix 30kg of wheat straw and 10kg of peanut shells, crush them together into pieces with a particle size of 2-3cm, and dry them until the moisture content is ≤10% to obtain the pretreated product; Step 2: Place the pretreated product in a high-temperature pyrolysis furnace, heat it to 450°C at a rate of 15°C / min in an oxygen-free environment, and maintain it at this temperature for 2 hours to carry out complete pyrolysis. Step 3: After pyrolysis, cool to room temperature in an anaerobic environment, remove and crush and grind, then pass through a 100-mesh sieve to obtain biochar powder; part of it is used for composting and fermenting organic fertilizer, and part of it is used to prepare supported biochar. Step 4: Mix 10 kg of the above biochar powder, 5 kg of shiitake mushroom residue powder and 50 kg of 1 mol / L phosphoric acid solution, stir at 80℃ for 2 h, filter, and set aside filter residue I and filtrate; add 10 g / L ammonium molybdate and 8 g / L boric acid to the filtrate, then add filter residue I, sonicate for 30 min, filter, and dry filter residue II to obtain supported biochar.

[0033] II. Preparation of well-rotted and fermented organic fertilizer: Step 5: Mix 10 kg of biochar powder, 10 kg of treated chicken manure, and 3 kg of wheat bran, and adjust the overall moisture content to about 60% to obtain mixed organic fertilizer; inoculate with 1.15 kg of Java Rhizopus liquid, and aerobic ferment at 25°C for 3 days, then aerobic compost fermentation to a temperature of 55-60°C and maintain for 2 days, then cool to room temperature to obtain the initial organic fertilizer product; then inoculate with 2.3 kg of Candida viscera liquid, and aerobic ferment at 25°C for 4 days, then aerobic compost fermentation and raise the temperature to 65-70°C and maintain for 2 days; Step 6: After fermentation is complete, dry and crush the material, and pass it through an 80-mesh sieve to obtain well-rotted and fermented organic fertilizer.

[0034] III. Microbial-fermented organic fertilizer granules: Step 7: Thoroughly mix 40 kg of well-rotted and fermented organic fertilizer and 3 kg of ferrous sulfate to obtain a mixture; add 5 kg of modified starch to 10 kg of water and stir evenly, then spray it onto the mixture while stirring to ensure even spraying. After drying, spray in a compound microbial agent suspension (the amount of agent is 2% of the total dry weight of the material) while stirring to ensure even inoculation. After drying, obtain the mixture. Step 8: Feed the mixture into the granulator, spray a small amount of water as a binder, and make spherical granules with a particle size of 3-4 mm. Step 9: Dry the granules at a low temperature below 50℃ with ventilation until the moisture content is <15%, to obtain microbial-fermented organic fertilizer granules.

[0035] IV. Preparation and coating of sustained-release membrane: Step 10: Add 3 kg of sodium alginate and 10 kg of supported biochar powder to 50 kg of water and stir evenly to form a mixed coating solution; Step 11: Place the microbial-fermented organic fertilizer granules in a coating machine. While the machine is in a rolling state, spray the coating liquid evenly onto the surface of the granules using a spraying method. Then spray a 4% calcium chloride solution to coat and solidify the granules. Place the coated granules in a low-temperature dryer and dry them until the moisture content of the granules is <10% (the weight gain of the coating is controlled at 5%-8% of the granule weight).

[0036] V. Aging and Packaging: Step 12: Aged the coated granules at room temperature for 24 hours to allow the coating to fully solidify, and then packaged to obtain slow-release carbon-based bio-organic fertilizer.

[0037] Example 4: Preparation of slow-release carbon-based bio-organic fertilizer I. Preparation of biochar powder and supported biochar: Step 1: Mix 28 kg of wheat straw and 10 kg of peanut shells, crush them together into pieces with a particle size of 2-3 cm, and dry them until the moisture content is ≤10% to obtain the pretreated product; Step 2: Place the pretreated product in a high-temperature pyrolysis furnace, heat it to 450°C at a rate of 20°C / min in an oxygen-free environment, and maintain it at this temperature for 2 hours to carry out complete pyrolysis. Step 3: After pyrolysis, cool to room temperature in an anaerobic environment, remove and crush and grind, then pass through a 100-mesh sieve to obtain biochar powder; part of it is used for composting and fermenting organic fertilizer, and part of it is used to prepare supported biochar. Step 4: Mix 10 kg of the above biochar powder, 4 kg of shiitake mushroom residue powder and 50 kg of 1 mol / L phosphoric acid solution, stir at 80℃ for 2 h, filter, and set aside filter residue I and filtrate; add 11 g / L of ammonium molybdate and 7 g / L of boric acid to the filtrate, then add filter residue I, sonicate for 30 min, filter, and dry filter residue II to obtain supported biochar.

[0038] II. Preparation of well-rotted and fermented organic fertilizer: Step 5: Mix 10 kg of biochar powder, 8 kg of treated chicken manure, and 3 kg of wheat bran, and adjust the overall moisture content to about 60% to obtain mixed organic fertilizer; inoculate with 1.05 kg of Javanese Rhizopus liquid, and aerobically ferment at 25°C for 3 days, then aerobically compost fermentation to a temperature of 55-60°C and maintain it for 2 days, then cool to room temperature to obtain the initial organic fertilizer product; then inoculate with 2.1 kg of Candida albicans liquid, and aerobically ferment at 28°C for 3 days, then aerobically compost fermentation and raise the temperature to 65-70°C and maintain it for 2 days; Step 6: After fermentation is complete, dry and crush the material, and pass it through an 80-mesh sieve to obtain well-rotted and fermented organic fertilizer.

[0039] III. Microbial-fermented organic fertilizer granules: Step 7: Thoroughly mix 40 kg of well-rotted and fermented organic fertilizer and 3 kg of ferrous sulfate to obtain a mixture; add 5 kg of modified starch to 10 kg of water and stir evenly, then spray the mixture onto the mixture while stirring to ensure even spraying. After drying, spray in a compound microbial agent suspension (the amount of agent is 2.5% of the total dry weight of the material) while stirring to ensure even inoculation. After drying, obtain the mixture. Step 8: Feed the mixture into the granulator, spray a small amount of water as a binder, and make spherical granules with a particle size of 3-4 mm. Step 9: Dry the granules at a low temperature below 50℃ with ventilation until the moisture content is <15%, to obtain microbial-fermented organic fertilizer granules.

[0040] IV. Preparation and coating of sustained-release membrane: Step 10: Add 3 kg of sodium alginate and 10 kg of supported biochar powder to 50 kg of water and stir evenly to form a mixed coating solution; Step 11: Place the microbial-fermented organic fertilizer granules in a coating machine. While the machine is in a rolling state, spray the coating liquid evenly onto the surface of the granules using a spraying method. Then spray a 4% calcium chloride solution to coat and solidify the granules. Place the coated granules in a low-temperature dryer and dry them until the moisture content of the granules is <10% (the weight gain of the coating is controlled at 5%-8% of the granule weight).

[0041] V. Aging and Packaging: Step 12: Aged the coated granules at room temperature for 24 hours to allow the coating to fully solidify, and then packaged to obtain slow-release carbon-based bio-organic fertilizer.

[0042] Comparative Example 1: Preparation of Slow-Release Carbon-Based Bio-Organic Fertilizer I. Preparation of supported biochar: Step 1: Mix 28 kg of wheat straw and 10 kg of peanut shells, crush them together into pieces with a particle size of 2-3 cm, and dry them until the moisture content is ≤10% to obtain the pretreated product; Step 2: Place the pretreated product in a high-temperature pyrolysis furnace, heat it to 450°C at a rate of 20°C / min in an oxygen-free environment, and maintain it at this temperature for 2 hours to carry out complete pyrolysis. Step 3: After pyrolysis, cool to room temperature in an oxygen-free environment, remove and crush and grind, then pass through a 100-mesh sieve to obtain biochar powder; Step 4: Mix 10 kg of the above biochar powder, 4 kg of shiitake mushroom residue powder and 50 kg of 1 mol / L phosphoric acid solution, stir at 80℃ for 2 h, filter, and set aside filter residue I and filtrate; add 11 g / L of ammonium molybdate and 7 g / L of boric acid to the filtrate, then add filter residue I, sonicate for 30 min, filter, and dry filter residue II to obtain supported biochar.

[0043] II. Preparation of well-rotted and fermented organic fertilizer: Step 5: Mix 8 kg of treated chicken manure and 3 kg of wheat bran, and adjust the overall moisture content to about 60% to obtain mixed organic fertilizer; inoculate with 1.05 kg of Java Rhizopus solution, and aerobic ferment at 25℃ for 3 days, then aerobic compost fermentation to a temperature of 55-60℃ and maintain it for 2 days. Step 6: After fermentation is complete, dry and crush the material, and pass it through an 80-mesh sieve to obtain well-rotted and fermented organic fertilizer.

[0044] III. Microbial-fermented organic fertilizer granules: Step 7: Thoroughly mix 40 kg of well-rotted and fermented organic fertilizer and 3 kg of ferrous sulfate to obtain a mixture; then spray in a compound microbial agent suspension (the amount of agent is 2.5% of the dry weight of the mixture), stirring while spraying to ensure uniform inoculation, and dry to obtain the mixture; Step 8: Feed the mixture into the granulator, spray a small amount of water as a binder, and make spherical granules with a particle size of 3-4 mm. Step 9: Dry the granules at a low temperature below 50℃ with ventilation until the moisture content is <15%, to obtain microbial-fermented organic fertilizer granules.

[0045] IV. Preparation and coating of sustained-release membrane: Step 10: Add 3 kg of sodium alginate and 10 kg of supported biochar powder to 50 kg of water and stir evenly to form a mixed coating solution; Step 11: Place the microbial-fermented organic fertilizer granules in a coating machine. While the machine is in a rolling state, spray the coating liquid evenly onto the surface of the granules using a spraying method. Then spray a 4% calcium chloride solution to coat and solidify the granules. Place the coated granules in a low-temperature dryer and dry them until the moisture content of the granules is <10% (the weight gain of the coating is controlled at 5%-8% of the granule weight).

[0046] V. Aging and Packaging: Step 12: Aged the coated granules at room temperature for 24 hours to allow the coating to fully solidify, and then packaged to obtain slow-release carbon-based bio-organic fertilizer.

[0047] Comparative Example 2: Preparation of Slow-Release Carbon-Based Bio-Organic Fertilizer I. Preparation of supported biochar: Step 1: Mix 28 kg of wheat straw and 10 kg of peanut shells, crush them together into pieces with a particle size of 2-3 cm, and dry them until the moisture content is ≤10% to obtain the pretreated product; Step 2: Place the pretreated product in a high-temperature pyrolysis furnace, heat it to 450°C at a rate of 20°C / min in an oxygen-free environment, and maintain it at this temperature for 2 hours to carry out complete pyrolysis. Step 3: After pyrolysis, cool to room temperature in an oxygen-free environment, remove and crush and grind, then pass through a 100-mesh sieve to obtain biochar powder; Step 4: Mix 10 kg of the above biochar powder, 4 kg of shiitake mushroom residue powder and 50 kg of 1 mol / L phosphoric acid solution, stir at 80℃ for 2 h, filter, and set aside filter residue I and filtrate; add 11 g / L of ammonium molybdate and 7 g / L of boric acid to the filtrate, then add filter residue I, sonicate for 30 min, filter, and dry filter residue II to obtain supported biochar.

[0048] II. Preparation of well-rotted and fermented organic fertilizer: Step 5: Mix 10 kg of biochar powder, 8 kg of treated chicken manure, and 3 kg of wheat bran, adjust the overall moisture content to about 60%, and perform aerobic composting fermentation at a temperature of 55-60℃ for 2 days. Step 6: After fermentation is complete, dry and crush the material, and pass it through an 80-mesh sieve to obtain well-rotted and fermented organic fertilizer.

[0049] III. Microbial-fermented organic fertilizer granules: Step 7: Thoroughly mix 10 kg of the above-mentioned loaded biochar powder, 40 kg of decomposed and fermented organic fertilizer, and 3 kg of humic acid to obtain a mixture; then spray in the compound microbial agent suspension (the amount of agent is 2.5% of the dry weight of the mixture), stirring while spraying to ensure uniform inoculation, and dry to obtain the mixture. Step 8: Feed the mixture into the granulator, spray a small amount of water as a binder, and make spherical granules with a particle size of 3-4 mm. Step 9: Dry the granules at a low temperature below 50℃ with ventilation until the moisture content is <15%, to obtain microbial-fermented organic fertilizer granules.

[0050] IV. Preparation and coating of sustained-release membrane: Step 10: Add 3 kg of sodium alginate to 50 kg of water and stir until well mixed to form a coating solution; Step 11: Place the microbial-fermented organic fertilizer granules in a coating machine. While the machine is in a rolling state, spray the coating liquid evenly onto the surface of the granules using a spraying method. Then spray a 4% calcium chloride solution to coat and solidify the granules. Place the coated granules in a low-temperature dryer and dry them until the moisture content of the granules is <10% (the weight gain of the coating is controlled at 5%-8% of the granule weight).

[0051] V. Aging and Packaging: Step 12: Aged the coated granules at room temperature for 24 hours to allow the coating to fully solidify, and then packaged to obtain slow-release carbon-based bio-organic fertilizer.

[0052] Comparative Example 3: Preparation of Slow-Release Carbon-Based Bio-Organic Fertilizer I. Preparation of biochar powder and supported biochar: Step 1: Mix 28 kg of wheat straw and 10 kg of peanut shells, crush them together into pieces with a particle size of 2-3 cm, and dry them until the moisture content is ≤10% to obtain the pretreated product; Step 2: Place the pretreated product in a high-temperature pyrolysis furnace, heat it to 450°C at a rate of 20°C / min in an oxygen-free environment, and maintain it at this temperature for 2 hours to carry out complete pyrolysis. Step 3: After pyrolysis, cool to room temperature in an anaerobic environment, remove and crush and grind, then pass through a 100-mesh sieve to obtain biochar powder; part of it is used for composting and fermenting organic fertilizer, and part of it is used to prepare supported biochar. Step 4: Mix 10 kg of the above biochar powder, 4 kg of attapulgite, and 50 kg of 1 mol / L phosphoric acid solution, stir at 80°C for 2 h, filter, and set aside filter residue I and filtrate; add 11 g / L of ammonium molybdate and 7 g / L of boric acid to the filtrate, then add filter residue I, sonicate for 30 min, filter, and dry filter residue II to obtain supported biochar.

[0053] II. Preparation of well-rotted and fermented organic fertilizer: Step 5: Mix 10 kg of the above-mentioned loaded biochar powder, 8 kg of treated chicken manure, and 3 kg of wheat bran, and then perform aerobic composting fermentation at a temperature of 55-60℃ for 2 days. After cooling to room temperature, the initial organic fertilizer product is obtained. Then, inoculate 2.1 kg of Candida albicans liquid and perform aerobic fermentation at 28℃ for 3 days. After that, perform aerobic composting fermentation and raise the temperature to 65-70℃ for 2 days. Step 6: After fermentation is complete, dry and crush the material, and pass it through an 80-mesh sieve to obtain well-rotted and fermented organic fertilizer.

[0054] III. Microbial-fermented organic fertilizer granules: Step 7: Thoroughly mix 40 kg of well-rotted and fermented organic fertilizer and 3 kg of ferrous sulfate to obtain a mixture; add 5 kg of modified starch to 10 kg of water and stir evenly, then spray the mixture onto the mixture while stirring to ensure even spraying. After drying, spray in a compound microbial agent suspension (the amount of agent is 2.5% of the total dry weight of the material) while stirring to ensure even inoculation. After drying, obtain the mixture. Step 8: Feed the mixture into the granulator, spray a small amount of water as a binder, and make spherical granules with a particle size of 3-4 mm. Step 9: Dry the granules at a low temperature below 50℃ with ventilation until the moisture content is <15%, to obtain microbial-fermented organic fertilizer granules.

[0055] IV. Preparation and coating of sustained-release membrane: Step 10: Add 3 kg of sodium alginate and 10 kg of biochar powder to 50 kg of water and stir evenly to form a mixed coating solution; Step 11: Place the microbial-fermented organic fertilizer granules in a coating machine. While the machine is in a rolling state, spray the coating liquid evenly onto the surface of the granules using a spraying method. Then spray a 4% calcium chloride solution to coat and solidify the granules. Place the coated granules in a low-temperature dryer and dry them until the moisture content of the granules is <10% (the weight gain of the coating is controlled at 5%-8% of the granule weight).

[0056] V. Aging and Packaging: Step 12: Aged the coated granules at room temperature for 24 hours to allow the coating to fully solidify, and then packaged to obtain slow-release carbon-based bio-organic fertilizer.

[0057] Field trial: The effects of slow-release biochar organic fertilizer on maize cultivation in slightly saline-alkali land I. Materials and Methods 1. Conditions of the test site This experimental site is located at our company's saline-alkali land planting base in Linshu County. The soil in the experimental site is slightly saline-alkali soil with moderate fertility; the main physicochemical properties are pH 7.9, salt content 0.53% (30cm topsoil), organic matter content 2.01g / kg, total nitrogen content 0.35g / kg, and total phosphorus content 0.48g / kg; the previous crop was wheat.

[0058] 2. Test materials The tested fertilizers were those described in Example 2 of this invention. The controlled-release carbon-based bio-organic fertilizer prepared by comparative examples 1-3, and the commercially available "Tankejia" compound fertilizer (biochar-based corn-specific fertilizer). The corn variety was Mingyu 268.

[0059] 3. Experimental Design The experiment included five treatments, each applying the aforementioned fertilizer (40 kg / mu). Corn was planted in a 4-row, wide-ridge pattern, with wide ridges 70 cm wide, narrow ridges 40 cm wide, and plant spacing of 30 cm. Each treatment was planted on 500 m² plots. 2 The fertilizer for each treatment was applied mechanically once one week before sowing, and watered once on the third day after application. No additional fertilizer was applied. Apart from fertilization, all other field management measures were the same for all treatment groups.

[0060] 4. Test Indicators Observe and record the emergence, jointing, tasseling, grain filling and maturity stages of corn.

[0061] The "five-point sampling method" was used, and 10 corn plants were randomly selected from each treatment group to compare plant height, tip length, and number of kernels per ear.

[0062] Each processing group measured the actual yield and calculated the output.

[0063] Soil samples from 0-20 cm depth were collected from each treatment group using the "five-point sampling method" to determine the soil physicochemical properties.

[0064] II. Results and Analysis 1. The Influence of Maize Growth Stage Statistical analysis of maize growth records showed that, under the same sowing date, the emergence and jointing dates of the treatment groups were relatively consistent, with treatment group 2 slightly earlier, but the overall difference was not significant. However, treatment group 2 showed significantly earlier tasseling, grain-filling, and maturity dates, while treatment group 1 was the latest, and the other treatment groups showed little difference. Results are shown below. Figure 1 , Figure 2 .

[0065] 2. Effects of maize growth traits and yield As shown in Table 1, treatment group 2 had the shortest barren tips, the most grains per ear, and the highest yield; treatment group 1 had the longest barren tips, the fewest grains per ear, and the lowest yield. The other treatment groups were at an intermediate level, but their data were significantly different from those of treatment group 2 (P < 0.05). There were no significant differences in plant height among the treatment groups (P > 0.05). Table 1 Effects of treatments on maize growth traits and yield

[0066] 3. The impact of soil at the test site As can be seen from Table 2, the soil physicochemical properties of each treatment group changed, with the most significant change in treatment group 2 and the smaller change in treatment group 1; compared with treatment group 2, all characterization data showed significant differences (P < 0.05).

[0067] Table 2 Effects of each treatment on soil physicochemical properties

Claims

1. A method for preparing a slow-release carbon-based bio-organic fertilizer, characterized in that, Includes the following steps: I. Preparation of biochar powder and supported biochar: Step 1: Mix wheat straw and peanut shells in a mass ratio of (2.5):1, crush and dry them to obtain the pretreated product; Step 2: Heat the pretreated product to 450-550℃ in an anaerobic environment at a rate of 15-20℃ / min and keep it at that temperature for 1-2 hours for pyrolysis. Step 3: After pyrolysis, cool and grind to obtain biochar powder; Step 4: Mix biochar powder, shiitake mushroom residue powder and 1 mol / L phosphoric acid solution at a mass ratio of 1:(0.3-0.5):5, stir at 80℃ for 2 hours, filter, and set aside filter residue I and filtrate; add ammonium molybdate and boric acid to the filtrate, then add filter residue I, sonicate, filter, and dry filter residue II to obtain supported biochar; II. Preparation of well-rotted and fermented organic fertilizer: Step 5: Mix the obtained biochar powder, chicken manure, and wheat bran in a mass ratio of 1:(0.7-1):0.3, adjust the moisture content to 60%, and obtain mixed organic fertilizer; inoculate with Java Rhizopus liquid, and aerobic ferment at 25-28℃ for 2-3 days, then aerobic compost fermentation to a temperature of 55-60℃ and maintain for 2 days, then cool to room temperature to obtain mature fermented organic fertilizer; then inoculate with Candida virescens liquid, and aerobic fermentation at 25-28℃ for 3-4 days, then aerobic compost fermentation and raise the temperature to 65-70℃ and maintain for 2 days; Step 6: After fermentation is complete, dry and crush to obtain well-rotted fermented organic fertilizer; III. Microbial-fermented organic fertilizer granules: Step 7: Mix the well-rotted and fermented organic fertilizer and ferrous sulfate evenly to obtain a mixture; add water to the modified starch and spray it onto the mixture, dry it, then spray in the compound microbial agent suspension, and dry it to obtain the mixture. Step 8: Feed the mixture into a granulator, spray a small amount of water as a binder, and form granules; Step 9: Dry the granules until the moisture content is <15% to obtain microbial-fermented organic fertilizer granules; IV. Preparation and coating of sustained-release membrane: Step 10: Add sodium alginate and the above-mentioned supported biochar to water and stir evenly to form a mixed coating solution; Step 11: Spray the mixed coating liquid onto the surface of the microbial-fermented organic fertilizer granules using a spraying method, and then spray with a 4% calcium chloride solution; dry the coated granules until the moisture content is <10% to obtain coated granules; V. Aging and Packaging: Step 12: Aged the coated granules at room temperature for 24 hours to allow the coating to fully solidify, and then packaged to obtain slow-release carbon-based bio-organic fertilizer.

2. The preparation method according to claim 1, characterized in that, In step 4, the amount of ammonium molybdate added is 10-12 g / L, and the amount of boric acid added is 5-8 g / L.

3. The preparation method according to claim 1, characterized in that, In step 5, the inoculation amount of Java Rhizopus liquid is 5% of the weight of the mixed organic fertilizer; the inoculation amount of Candida viviparus liquid is 10% of the weight of the mixed organic fertilizer.

4. The preparation method according to claim 1, characterized in that, In step 7, the mass ratio of fermented organic fertilizer, ferrous sulfate, modified starch, and water is 40:3:5:

10.

5. The preparation method according to claim 1, characterized in that, The method for preparing the modified starch in step 7 is as follows: Add 100g corn starch and 30g humic acid to 300g deionized water, stir well, heat to 80℃, stir until the starch is completely gelatinized, cool, dry, pulverize, add 100g molten maleic anhydride, stir and react at 80℃ for 2h, cool, wash with anhydrous ethanol, dry to obtain the initial product; dissolve 100g of the initial product in an appropriate amount of water, adjust the pH to 5.0, add 5mL of initiator, after 20min add 20g acrylamide and 10g acryloyloxyethyltrimethylammonium chloride, stir at 80℃ for 2h, cool to room temperature, wash with anhydrous ethanol, dry, pulverize to obtain the modified starch.

6. The preparation method according to claim 5, characterized in that, The initiator in the modified starch preparation method is prepared by dissolving 5g of cerium ammonium nitrate in 100mL of 0.1mol / L nitric acid solution.

7. The preparation method according to claim 1, characterized in that, In step 7, the amount of compound microbial agent suspension used is 2-3% of the total dry weight of the material.

8. The preparation method according to claim 1, characterized in that, The compound microbial agent suspension in step 7 contains Bacillus megaterium solution, Bacillus pumilus solution, and Bacillus subtilis solution in a volume ratio of 1:5:

3.

9. The preparation method according to claim 1, characterized in that, In step 10, the mass ratio of sodium alginate, supported biochar, and water is 3:10:

50.

10. The preparation method according to claim 1, characterized in that, In step 11, the coating weight gain is 5-8% of the particle mass.

Images