A carbon-fixing and nitrogen-preserving biological organic fertilizer and its preparation method

Abstract

The present invention belongs to the technical field of biological fertilizers. Specifically, the present invention provides a carbon-fixing and nitrogen-preserving biological organic fertilizer and a preparation method thereof. In the present invention, molybdenum, copper, cobalt and a composite bacterial community are loaded on biomass charcoal to obtain loaded biomass charcoal, and then the loaded biomass charcoal, perilla biomass extract and animal feces are jointly formulated into a biological organic fertilizer. The biological organic fertilizer provided by the present invention can avoid unnecessary waste of strain resources, and the organic fertilizer can significantly promote the fixation of ammonium nitrogen and nitrate nitrogen by the soil; the composite bacterial liquid promotes the decomposition of organic matter and the availability of nutrients, and promotes the improvement of the soil, so as to facilitate the improvement of soil productivity; at the same time, the organic fertilizer can significantly improve the soil enzyme activity, promote the improvement of soil fertility, and finally realize the function of soil conditioning.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological fertilizers, and specifically relates to a carbon-fixing and nitrogen-preserving biological organic fertilizer and a preparation method thereof. Background Art

[0002] For a long time, the rapid development of agriculture, the excessive application of chemical fertilizers, unreasonable farming methods, etc. have led to the imbalance of the soil carbon-nitrogen cycle. The excessive application of chemical fertilizers has caused large-area pollution of soil and groundwater, the decline in the quality of agricultural products, and at the same time increased the emission of greenhouse gases. With the continuous improvement of people's attention to food safety and the ecological environment, green food and organic agriculture have developed rapidly.

[0003] Biological organic fertilizer is a fertilizer composed of specific functional microorganisms and harmlessly treated livestock and poultry manure, crop straws, and decomposed organic materials, which has the dual effects of microbial fertilizer and organic fertilizer efficiency. Biological organic fertilizer contains rich organic carbon. Applying biological organic fertilizer can increase the input of organic carbon in the soil, promote the accumulation of soil organic carbon, and improve the carbon-fixing ability of the soil. By optimizing the way of returning straw and animal organic fertilizer to the field, reducing the content of easily decomposable carbon in organic materials and increasing the content of difficult-to-decompose carbon, methane emissions can be effectively controlled and the carbon-fixing effect of the soil can be improved. The nitrogen in biological organic fertilizer mainly exists in an organic state. After being applied to the soil, it is gradually released through the decomposition of microorganisms, which can provide a continuous and stable nitrogen supply for crops and reduce nitrogen loss.

[0004] However, the nutrient content of existing biological organic fertilizers is relatively low, and the release rate and utilization rate of nutrients are not yet ideal. Therefore, it is an urgent practical need to further increase the nutrient content in biological organic fertilizers to better meet the growth needs of crops. The existing biological organic fertilizers have low carbon-fixing efficiency. Screening and cultivating more efficient carbon-fixing and nitrogen-preserving microbial strains and adding them to biological organic fertilizers to improve the microbial activity and quantity in the soil, thereby improving the carbon-fixing and nitrogen-preserving ability of biological organic fertilizers, is an important development direction in the technical field of biological fertilizers. Summary of the Invention

[0005] Aiming at the technical problems existing in the prior art, the purpose of the present invention is to provide a carbon-fixing and nitrogen-preserving biological organic fertilizer and a preparation method thereof.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention provides a preparation method of a carbon-fixing and nitrogen-preserving biological organic fertilizer, comprising the following steps:

[0008] (1) crushing corn stalks and polyvinyl alcohol resin by weight, mixing them evenly with a solution containing potassium carbonate and potassium hydroxide, drying them, placing the dried mixture in a carbonization furnace, and carbonizing them under a nitrogen atmosphere to obtain activated biomass charcoal;

[0009] (2) immersing the activated biochar prepared in step (1) into a mixed solution containing H2O2 and dicobalt ethylenediaminetetraacetate, stirring the mixture for 2-4 hours, and grinding the mixture to obtain a hierarchical pore structure product;

[0010] (3) mixing the hierarchical pore structure product prepared in step (2) with a composite bacterial solution, and stirring for 1-2 hours to obtain modified biochar, wherein the composite bacterial solution is obtained by mixing azotobacter nitrogen-fixing bacteria, Pantoea anacardiae and Aspergillus niger solution;

[0011] (4) immersing the modified biochar prepared in step (3) into a mixed solution containing tetraamminecopper sulfate and Mo-EDTA complex, stirring and reacting for 1-2 hours to obtain a supported biochar;

[0012] (5) The loaded biochar, perilla biomass extract and animal manure are fully mixed, stirred for 20-30 minutes, and concentrated to obtain a carbon-fixing and nitrogen-retaining biological organic fertilizer.

[0013] Furthermore, in step (1), the mass ratio of corn stalks to polyvinyl alcohol resin is 100:(1-10), and the carbonization temperature is 700-800°C.

[0014] Furthermore, in step (2), the mass ratio of the activated biochar to the dicobalt ethylenediaminetetraacetate in the mixed solution is 1:(0.01-0.2), and the stirring time is 2 hours.

[0015] Furthermore, in step (3), the mass ratio of brown spherical nitrogen-fixing bacteria, ananastomata and Aspergillus niger is 2:(1-2):(1-2), and the total mass of the bacteria in the composite bacterial solution is 2-30% of the mass of the hierarchical pore structure product prepared in step (2).

[0016] Furthermore, the method for preparing the perilla biomass extract in step (5) comprises: adding perilla to water and stirring for 10 minutes, and heat-treating the obtained juice for 2-3 hours at a heat treatment temperature of 80-120° C. to obtain the perilla biomass extract.

[0017] Furthermore, 5-60 grams of perilla are added to every 1L of water.

[0018] Furthermore, in step (4), the mass ratio of the modified biochar, tetraamminecopper sulfate and Mo-EDTA complex is 1:(0.05-0.2):(0.05-0.2).

[0019] Furthermore, in step (5), the mass ratio of the supported biochar, the perilla biomass extract and the animal feces is 1:(10-100):(10-100).

[0020] The present invention selects potassium hydroxide and potassium carbonate as activators to activate corn stalks and polyvinyl alcohol resins rich in oxygen-containing functional groups to prepare activated biochar. Compared with other conventionally selected activators such as sodium hydroxide, potassium hydroxide and potassium carbonate jointly activate corn stalks and polyvinyl alcohol resins, which is more conducive to the load of strains in the composite bacterial liquid on biochar, improves the utilization efficiency of strains, and thus improves the carbon fixation and nitrogen retention capacity of the organic fertilizer finally prepared. Potassium hydroxide and potassium carbonate synergistically activate the biomass system composed of straw and polyvinyl alcohol resin, and can prepare biochar with a hierarchical pore structure, in which the large pores account for a large proportion, ensuring the high loading rate of subsequent strains on the surface of biochar, and appropriate metal cobalt complexes, metal molybdenum and copper complexes, and strains are all loaded in the corresponding pore structure, further improving the pore utilization efficiency in the biochar.

[0021] In the preparation process of the present invention, the composite bacterial community is first loaded onto the biochar and then the complex of metal molybdenum and copper is loaded. Since the molecular size of the complex of metal molybdenum and copper is much smaller than the size of the strains in the composite bacterial solution, the complex is combined with the active sites on the biochar formed between the strains, and the active sites on the biochar are fully utilized, thereby improving the utilization efficiency of the active sites in the biochar and ensuring the loading efficiency of the strains in the composite bacterial solution.

[0022] The present invention adopts brown spherical nitrogen-fixing bacteria, ananastomata and black Aspergillus as composite bacteria. In addition to the mutual cooperation between the self-generated nitrogen-fixing bacteria and the degrading bacteria, and the mutual provision of energy substances between the bacterial species, the intermediate product of a certain bacterial species may be more conducive to the degradation or nitrogen fixation of other bacterial species. Compared with the composite bacteria obtained by combining other bacterial species, the composite bacteria recorded in the present invention can make the organic fertilizer have better fertility, accelerate the nitrogen fixation process, and improve the nitrogen fixation efficiency.

[0023] The present invention adopts dicobalt ethylenediaminetetraacetate, tetraamminecopper sulfate and Mo-EDTA complex as precursors of metal components. Compared with metal inorganic salt components, low salinity of organic fertilizer can be ensured, thereby avoiding high mortality of beneficial soil bacteria. At the same time, the selection of Mo-EDTA complex can be used to provide high level of molybdenum to the surface of biochar in a stable liquid preparation.

[0024] The present invention uses perilla as the raw material of the biomass extract. First, perilla can be obtained in large quantities without special cultivation. Perilla also has a high nitrogen content. Compared with other plants, the nitrogen can be prepared through the biomass extract to have a high nitrogen recovery rate, and then introduced into the soil through the organic fertilizer of the present invention.

[0025] The invention also provides a carbon-fixing and nitrogen-retaining biological organic fertilizer prepared by the preparation method.

[0026] Beneficial effects of the present invention:

[0027] 1. In the present invention, molybdenum, copper, cobalt and composite bacterial flora are loaded on biochar to prepare organic fertilizer, which can avoid unnecessary waste of bacterial resources, and the organic fertilizer can significantly promote the fixation of ammonium nitrogen and nitrate nitrogen in the soil.

[0028] 2. The present invention finds that by using brown spherical nitrogen-fixing bacteria, ananastomata and black Aspergillus as composite bacteria, in addition to the mutual synergy between spontaneous nitrogen-fixing bacteria and degrading bacteria, and the provision of energy substances between the species, the intermediate products of a certain species may be more conducive to the degradation or nitrogen fixation of other species. Compared with the composite bacteria obtained by combining other species, the composite bacteria recorded in the present invention can make the organic fertilizer have better fertility, accelerate the nitrogen fixation process, and improve the nitrogen fixation efficiency.

[0029] 3. The present invention uses corn stalks and polyvinyl alcohol resin as biomass raw materials to prepare biochar. After activation with potassium hydroxide and potassium carbonate, biochar with a spatial three-dimensional cross-linked structure can be prepared. The biochar forms a large number of small chambers, which are loaded with composite bacterial communities after oxidation. These composite bacterial communities reproduce in large numbers with the help of the heat preservation and moisture retention effects brought by the small chambers, thereby promoting the improvement of the fertility of organic fertilizers.

[0030] 4. The organic fertilizer in the present invention can increase the organic matter and nitrogen content of the soil, adjust the pH value, and the composite bacterial solution can promote the decomposition of organic matter and the effectiveness of nutrients, promote soil improvement, and thus facilitate the improvement of soil productivity; at the same time, the organic fertilizer can significantly increase the activity of soil enzymes, promote the improvement of soil fertility, and ultimately achieve the effect of soil conditioning. DETAILED DESCRIPTION

[0031] 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 described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Unless otherwise specified, the raw materials and equipment used in the embodiments of the present invention are raw materials and equipment from conventional sources in the art. The endpoints and any values ​​of the scope disclosed in this article are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, between the endpoint values ​​of each scope, between the endpoint values ​​of each scope and a separate point value, and between separate point values, one or more new numerical ranges can be combined with each other, and these numerical ranges should be considered as specifically disclosed in this article.

[0033] Example 1

[0034] A carbon-fixing and nitrogen-retaining biological organic fertilizer is prepared by the following preparation method:

[0035] (1) Weighing corn stalks and polyvinyl alcohol resin at a mass ratio of 100:1, crushing the corn stalks and the polyvinyl alcohol resin, mixing them evenly with a solution containing potassium carbonate and potassium hydroxide, and drying them. The dried mixture is placed in a carbonization furnace and carbonized at 700° C. under a nitrogen atmosphere to obtain activated biochar;

[0036] (2) immersing the activated biochar prepared in step (1) into a mixed solution containing H2O2 and dicobalt ethylenediaminetetraacetate, wherein the mass ratio of the activated biochar to the dicobalt ethylenediaminetetraacetate in the mixed solution is 1:0.01, stirring the reaction for 2 hours, and grinding to obtain a hierarchical pore structure product;

[0037] (3) mixing the hierarchical pore structure product prepared in step (2) with the composite bacterial solution and stirring for 1 hour to obtain modified biochar;

[0038] The composite bacterial solution is obtained by mixing brown spherical nitrogen-fixing bacteria, ananastomella and Aspergillus niger, wherein the mass ratio of brown spherical nitrogen-fixing bacteria, ananastomella and Aspergillus niger is 2:1:1, and the total mass of the bacterial species in the composite bacterial solution is 2% of the mass of the hierarchical pore structure product prepared in step (2);

[0039] (4) immersing the modified biochar prepared in step (3) into a mixed solution containing tetraamminecopper sulfate and Mo-EDTA complex, wherein the mass ratio of the modified biochar, tetraamminecopper sulfate and Mo-EDTA complex is 1:0.05:0.05, and stirring the reaction for 1 hour to obtain a supported biochar;

[0040] (5) The loaded biochar, perilla biomass extract and animal manure were fully mixed in a mass ratio of 1:20:80, stirred for 20 minutes, and concentrated to obtain a carbon-fixing and nitrogen-retaining biological organic fertilizer.

[0041] The preparation method of the perilla biomass extract comprises: adding 5g of perilla into 1L of water and stirring for 10min, heat-treating the obtained juice for 2h at a heat treatment temperature of 80°C to obtain the perilla biomass extract.

[0042] Example 2

[0043] A carbon-fixing and nitrogen-retaining biological organic fertilizer is prepared by the following preparation method:

[0044] (1) Weighing corn stalks and polyvinyl alcohol resin in a mass ratio of 100:3, crushing the corn stalks and the polyvinyl alcohol resin, mixing them evenly with a solution containing potassium carbonate and potassium hydroxide, and drying them. The dried mixture is placed in a carbonization furnace and carbonized at 730° C. under a nitrogen atmosphere to obtain activated biochar;

[0045] (2) immersing the activated biochar prepared in step (1) into a mixed solution containing H2O2 and dicobalt ethylenediaminetetraacetate, wherein the mass ratio of the activated biochar to the dicobalt ethylenediaminetetraacetate in the mixed solution is 1:0.05, stirring the reaction for 2 hours, and grinding to obtain a hierarchical pore structure product;

[0046] (3) mixing the hierarchical pore structure product prepared in step (2) with the composite bacterial solution and stirring for 1.5 hours to obtain modified biochar;

[0047] The composite bacterial solution is obtained by mixing brown spherical nitrogen-fixing bacteria, ananastomella and Aspergillus niger, wherein the mass ratio of brown spherical nitrogen-fixing bacteria, ananastomella and Aspergillus niger is 2:1.2:1.2, and the total mass of the bacterial species in the composite bacterial solution is 10% of the mass of the hierarchical pore structure product prepared in step (2);

[0048] (4) immersing the modified biochar prepared in step (3) into a mixed solution containing tetraamminecopper sulfate and Mo-EDTA complex, wherein the mass ratio of the modified biochar, tetraamminecopper sulfate and Mo-EDTA complex is 1:0.08:0.08, and stirring the reaction for 1 hour to obtain a supported biochar;

[0049] (5) The loaded biochar, perilla biomass extract and animal manure were fully mixed in a mass ratio of 1:30:70, stirred for 25 minutes, and concentrated to obtain a carbon-fixing and nitrogen-retaining biological organic fertilizer.

[0050] The preparation method of the perilla biomass extract comprises: adding 10g of perilla into 1L of water and stirring for 10min, heat-treating the obtained juice for 2.5h at a heat treatment temperature of 90°C to obtain the perilla biomass extract.

[0051] Example 3

[0052] A carbon-fixing and nitrogen-retaining biological organic fertilizer is prepared by the following preparation method:

[0053] (1) Weighing corn stalks and polyvinyl alcohol resin in a mass ratio of 100:5, crushing the corn stalks and the polyvinyl alcohol resin, mixing them evenly with a solution containing potassium carbonate and potassium hydroxide, and drying them. The dried mixture is placed in a carbonization furnace and carbonized at 750° C. under a nitrogen atmosphere to obtain activated biochar;

[0054] (2) immersing the activated biochar prepared in step (1) into a mixed solution containing H2O2 and dicobalt ethylenediaminetetraacetate, wherein the mass ratio of the activated biochar to the dicobalt ethylenediaminetetraacetate in the mixed solution is 1:0.08, stirring the reaction for 3 hours, and grinding to obtain a hierarchical pore structure product;

[0055] (3) mixing the hierarchical pore structure product prepared in step (2) with the composite bacterial solution and stirring for 1.5 hours to obtain modified biochar;

[0056] The composite bacterial solution is obtained by mixing brown spherical nitrogen-fixing bacteria, ananastomella and Aspergillus niger, wherein the mass ratio of brown spherical nitrogen-fixing bacteria, ananastomella and Aspergillus niger is 2:1.5:1.5, and the total mass of the bacterial species in the composite bacterial solution is 15% of the mass of the hierarchical pore structure product prepared in step (2);

[0057] (4) immersing the modified biochar prepared in step (3) into a mixed solution containing tetraamminecopper sulfate and Mo-EDTA complex, wherein the mass ratio of the modified biochar, tetraamminecopper sulfate and Mo-EDTA complex is 1:0.1:0.1, and stirring the reaction for 1.5 hours to obtain a supported biochar;

[0058] (5) The loaded biochar, perilla biomass extract and animal manure were fully mixed in a mass ratio of 1:40:60, stirred for 25 minutes, and concentrated to obtain a carbon-fixing and nitrogen-retaining biological organic fertilizer.

[0059] The preparation method of the perilla biomass extract comprises: adding 30g of perilla into 1L of water and stirring for 10min, heat-treating the obtained juice for 2.5h at a heat treatment temperature of 90°C to obtain the perilla biomass extract.

[0060] Example 4

[0061] A carbon-fixing and nitrogen-retaining biological organic fertilizer is prepared by the following preparation method:

[0062] (1)Weigh corn straw and polyvinyl alcohol resin according to a mass ratio of 100:7. After crushing the corn straw and polyvinyl alcohol resin, mix them evenly with a solution containing potassium carbonate and potassium hydroxide, dry them, and place the dried mixture in a carbonization furnace. Carbonize it at 760 °C under a nitrogen atmosphere to obtain activated biomass carbon;

[0063] (2)Immerse the activated biomass carbon prepared in step (1) into a mixed solution containing H2O2 and cobalt (II) ethylenediaminetetraacetate. The mass ratio of the activated biomass carbon to cobalt (II) ethylenediaminetetraacetate in the mixed solution is 1:0.1. Stir and react for 3 h, and then grind to obtain a hierarchical pore structure product;

[0064] (3)Mix the hierarchical pore structure product prepared in step (2) with a composite bacterial solution, and stir for 1.5 h to obtain modified biomass carbon;

[0065] The composite bacterial solution is obtained by mixing Azotobacter chroococcum, Pantoea ananatis, and Aspergillus niger bacterial solutions. The mass ratio of Azotobacter chroococcum, Pantoea ananatis, and Aspergillus niger is 2:1.7:1.7. The total mass of the bacterial species in the composite bacterial solution is 20% of the mass of the hierarchical pore structure product prepared in step (2);

[0066] (4)Immerse the modified biomass carbon prepared in step (3) into a mixed solution containing tetraamminecopper (II) sulfate and Mo-EDTA complex. The mass ratio of the modified biomass carbon, tetraamminecopper (II) sulfate, and Mo-EDTA complex is 1:0.15:0.15. Stir and react for 2 h to obtain supported biomass carbon;

[0067] (5)Fully mix the supported biomass carbon, perilla biomass extract, and animal manure. The mass ratio of the supported biomass carbon, perilla biomass extract, and animal manure is 1:30:60. Stir for 30 min and concentrate to obtain a carbon sequestration and nitrogen conservation bio-organic fertilizer.

[0068] The preparation method of the perilla biomass extract includes: adding 40 g of perilla to 1 L of water and stirring for 10 min, and performing heat treatment on the obtained juice for 2.5 h at a heat treatment temperature of 100 °C to obtain the perilla biomass extract.

[0069] Example 5

[0070] A carbon sequestration and nitrogen conservation bio-organic fertilizer is prepared by the following preparation method:

[0071] (1)Weigh corn straw and polyvinyl alcohol resin according to a mass ratio of 100:9. After crushing the corn straw and polyvinyl alcohol resin, mix them evenly with a solution containing potassium carbonate and potassium hydroxide, dry them, and place the dried mixture in a carbonization furnace. Carbonize it at 780 °C under a nitrogen atmosphere to obtain activated biomass carbon;

[0072] (2) Immerse the activated biomass carbon prepared in step (1) into a mixed solution containing H2O2 and cobalt (II) ethylenediaminetetraacetate. The mass ratio of the activated biomass carbon to cobalt (II) ethylenediaminetetraacetate in the mixed solution is 1:0.15. Stir and react for 3 h, then grind to obtain a hierarchical pore structure product;

[0073] (3) Mix the hierarchical pore structure product prepared in step (2) with the compound bacterial solution, and stir for 2 h to obtain modified biomass carbon;

[0074] The compound bacterial solution is obtained by mixing Azotobacter chroococcum, Pantoea ananatis, and Aspergillus niger bacterial solutions. The mass ratio of Azotobacter chroococcum, Pantoea ananatis, and Aspergillus niger is 2:1.9:1.9. The total mass of the bacterial strains in the compound bacterial solution is 25% of the mass of the hierarchical pore structure product prepared in step (2);

[0075] (4) Immerse the modified biomass carbon prepared in step (3) into a mixed solution containing tetraamminecopper (II) sulfate and Mo-EDTA complex. The mass ratio of the modified biomass carbon, tetraamminecopper (II) sulfate, and Mo-EDTA complex is 1:0.18:0.18. Stir and react for 2 h to obtain supported biomass carbon;

[0076] (5) Thoroughly mix the supported biomass carbon, perilla biomass extract, and animal manure. The mass ratio of the supported biomass carbon, perilla biomass extract, and animal manure is 1:25:55. Stir for 30 min, then concentrate to obtain a carbon sequestration and nitrogen conservation bio-organic fertilizer.

[0077] The preparation method of the perilla biomass extract includes: adding 50 g of perilla to 1 L of water, stirring for 10 min, and subjecting the obtained juice to heat treatment at 100 °C for 3 h to obtain the perilla biomass extract.

[0078] Example 6

[0079] A carbon sequestration and nitrogen conservation bio-organic fertilizer is prepared by the following method:

[0080] (1) Weigh corn straw and polyvinyl alcohol resin according to a mass ratio of 100:10. After crushing the corn straw and polyvinyl alcohol resin, mix them evenly with a solution containing potassium carbonate and potassium hydroxide, dry, and place the dried mixture in a carbonization furnace. Carbonize at 800 °C under a nitrogen atmosphere to obtain activated biomass carbon;

[0081] (2) Immerse the activated biomass carbon prepared in step (1) into a mixed solution containing H2O2 and cobalt (II) ethylenediaminetetraacetate. The mass ratio of the activated biomass carbon to cobalt (II) ethylenediaminetetraacetate in the mixed solution is 1:0.2. Stir and react for 4 h, then grind to obtain a hierarchical pore structure product;

[0082] (3) Mix the hierarchically porous structure product prepared in step (2) with the complex bacterial solution and stir for 2 h to obtain modified biochar.

[0083] The complex bacterial solution is obtained by mixing Azotobacter chroococcum, Pantoea ananatis, and Aspergillus niger bacterial solutions, where the mass ratio of Azotobacter chroococcum, Pantoea ananatis, and Aspergillus niger is 2:2:2, and the total mass of the bacterial strains in the complex bacterial solution is 30% of the mass of the hierarchically porous structure product prepared in step (2).

[0084] (4) Immerse the modified biochar prepared in step (3) into a mixed solution containing tetraamminecopper(II) sulfate and Mo-EDTA complex. The mass ratio of the modified biochar, tetraamminecopper(II) sulfate, and Mo-EDTA complex is 1:0.2:0.2, and stir and react for 2 h to obtain supported biochar.

[0085] (5) Thoroughly mix the supported biochar, perilla biomass extract, and animal manure. The mass ratio of the supported biochar, perilla biomass extract, and animal manure is 1:25:50, stir for 30 min, and concentrate to obtain a carbon sequestration and nitrogen conservation bio-organic fertilizer.

[0086] The preparation method of the perilla biomass extract includes: adding 60 g of perilla to 1 L of water, stirring for 10 min, and subjecting the obtained juice to heat treatment at 110°C for 3 h to obtain the perilla biomass extract.

[0087] Comparative Example 1

[0088] A carbon sequestration and nitrogen conservation bio-organic fertilizer is prepared by the following method:

[0089] (1) Weigh corn straw and polyvinyl alcohol resin at a mass ratio of 100:5. After crushing the corn straw and polyvinyl alcohol resin, mix them evenly with a solution containing sodium carbonate and sodium hydroxide, dry, place the dried mixture in a carbonization furnace, and carbonize it at 750°C under a nitrogen atmosphere to obtain activated biochar.

[0090] (2) Immerse the activated biochar prepared in step (1) into a mixed solution containing H2O2 and cobalt(II) ethylenediaminetetraacetate. The mass ratio of the activated biochar to cobalt(II) ethylenediaminetetraacetate in the mixed solution is 1:0.08, stir and react for 3 h, and grind to obtain a hierarchically porous structure product.

[0091] (3) Mix the hierarchically porous structure product prepared in step (2) with the complex bacterial solution and stir for 1.5 h to obtain modified biochar.

[0092] The composite bacterial liquid is obtained by mixing Azotobacter chroococcum, Pantoea ananatis and Aspergillus niger liquid, wherein the mass ratio of Azotobacter chroococcum, Pantoea ananatis and Aspergillus niger is 2:1.5:1.5, and the total mass of the strains in the composite bacterial liquid is 15% of the mass of the hierarchical pore structure product prepared in step (2);

[0093] (4)Immerse the modified biomass carbon prepared in step (3) into a mixed solution containing tetraamminecopper sulfate and Mo-EDTA complex. The mass ratio of the modified biomass carbon, tetraamminecopper sulfate and Mo-EDTA complex is 1:0.1:0.1, and stir and react for 1.5 h to obtain the supported biomass carbon;

[0094] (5)Fully mix the supported biomass carbon, perilla biomass extract and animal feces. The mass ratio of the supported biomass carbon, perilla biomass extract and animal feces is 1:40:60, stir for 25 min, and concentrate to obtain the carbon sequestration and nitrogen conservation bio-organic fertilizer.

[0095] The preparation method of the perilla biomass extract includes: adding 30 g of perilla to 1 L of water, stirring for 10 min, and performing heat treatment on the obtained juice for 2.5 h at a heat treatment temperature of 90 °C to obtain the perilla biomass extract.

[0096] Comparative Example 2

[0097] A carbon sequestration and nitrogen conservation bio-organic fertilizer is prepared by the following preparation method:

[0098] (1)Weigh corn straw and polyvinyl alcohol resin according to a mass ratio of 100:5. After crushing the corn straw and polyvinyl alcohol resin, mix them evenly with a solution containing potassium carbonate and potassium hydroxide, dry, and place the dried mixture in a carbonization furnace. Carbonize at 750 °C under a nitrogen atmosphere to obtain activated biomass carbon;

[0099] (2)Immerse the activated biomass carbon prepared in step (1) into a mixed solution containing H2O2 and cobalt ethylenediaminetetraacetate. The mass ratio of the activated biomass carbon to cobalt ethylenediaminetetraacetate in the mixed solution is 1:0.08, stir and react for 3 h, and grind to obtain a hierarchical pore structure product;

[0100] (3)Mix the hierarchical pore structure product prepared in step (2) with the composite bacterial liquid, and stir for 1.5 h to obtain modified biomass carbon;

[0101] The composite bacterial liquid is obtained by mixing Azotobacter chroococcum, Pantoea ananatis and Aspergillus niger liquid, wherein the mass ratio of Azotobacter chroococcum, Pantoea ananatis and Aspergillus niger is 2:1.5:1.5, and the total mass of the strains in the composite bacterial liquid is 15% of the mass of the hierarchical pore structure product prepared in step (2);

[0102] (4) immersing the modified biochar prepared in step (3) into a mixed solution containing copper sulfate and Mo-EDTA complex, wherein the mass ratio of the modified biochar, copper sulfate and Mo-EDTA complex is 1:0.1:0.1, and stirring the reaction for 1.5 hours to obtain a supported biochar;

[0103] (5) The loaded biochar, perilla biomass extract and animal manure were fully mixed in a mass ratio of 1:40:60, stirred for 25 minutes, and concentrated to obtain a carbon-fixing and nitrogen-retaining biological organic fertilizer.

[0104] The preparation method of the perilla biomass extract comprises: adding 30g of perilla into 1L of water and stirring for 10min, heat-treating the obtained juice for 2.5h at a heat treatment temperature of 90°C to obtain the perilla biomass extract.

[0105] Comparative Example 3

[0106] A carbon-fixing and nitrogen-retaining biological organic fertilizer is prepared by the following preparation method:

[0107] (1) Weighing corn stalks and polyvinyl alcohol resin in a mass ratio of 100:5, crushing the corn stalks and the polyvinyl alcohol resin, mixing them evenly with a solution containing potassium carbonate and potassium hydroxide, and drying them. The dried mixture is placed in a carbonization furnace and carbonized at 750° C. under a nitrogen atmosphere to obtain activated biochar;

[0108] (2) immersing the activated biochar prepared in step (1) into a mixed solution containing H2O2 and dicobalt ethylenediaminetetraacetate, wherein the mass ratio of the activated biochar to the dicobalt ethylenediaminetetraacetate in the mixed solution is 1:0.08, stirring the reaction for 3 hours, and grinding to obtain a hierarchical pore structure product;

[0109] (3) mixing the hierarchical pore structure product prepared in step (2) with the composite bacterial solution and stirring for 1.5 hours to obtain modified biochar;

[0110] The composite bacterial solution is obtained by mixing brown spherical nitrogen-fixing bacteria, Frankia and Aspergillus niger, wherein the mass ratio of brown spherical nitrogen-fixing bacteria, Frankia and Aspergillus niger is 2:1.5:1.5, and the total mass of the bacterial species in the composite bacterial solution is 15% of the mass of the hierarchical pore structure product prepared in step (2);

[0111] (4) immersing the modified biochar prepared in step (3) into a mixed solution containing tetraamminecopper sulfate and Mo-EDTA complex, wherein the mass ratio of the modified biochar, tetraamminecopper sulfate and Mo-EDTA complex is 1:0.1:0.1, and stirring the reaction for 1.5 hours to obtain a supported biochar;

[0112] (5) The loaded biochar, perilla biomass extract and animal manure were fully mixed in a mass ratio of 1:40:60, stirred for 25 minutes, and concentrated to obtain a carbon-fixing and nitrogen-retaining biological organic fertilizer.

[0113] The preparation method of the perilla biomass extract comprises: adding 30g of perilla into 1L of water and stirring for 10min, heat-treating the obtained juice for 2.5h at a heat treatment temperature of 90°C to obtain the perilla biomass extract.

[0114] Comparative Example 4

[0115] A carbon-fixing and nitrogen-retaining biological organic fertilizer is prepared by the following preparation method:

[0116] (1) Weighing corn stalks and polyvinyl alcohol resin in a mass ratio of 100:5, crushing the corn stalks and the polyvinyl alcohol resin, mixing them evenly with a solution containing potassium carbonate and potassium hydroxide, and drying them. The dried mixture is placed in a carbonization furnace and carbonized at 750° C. under a nitrogen atmosphere to obtain activated biochar;

[0117] (2) immersing the activated biochar prepared in step (1) into a mixed solution containing H2O2 and dicobalt ethylenediaminetetraacetate, wherein the mass ratio of the activated biochar to the dicobalt ethylenediaminetetraacetate in the mixed solution is 1:0.08, stirring the reaction for 3 hours, and grinding to obtain a hierarchical pore structure product;

[0118] (3) mixing the hierarchical pore structure product prepared in step (2) with the composite bacterial solution and stirring for 1.5 hours to obtain modified biochar;

[0119] The composite bacterial solution is obtained by mixing brown spherical nitrogen-fixing bacteria, Bacillus subtilis and Aspergillus niger, wherein the mass ratio of brown spherical nitrogen-fixing bacteria, Bacillus subtilis and Aspergillus niger is 2:1.5:1.5, and the total mass of the bacterial species in the composite bacterial solution is 15% of the mass of the hierarchical pore structure product prepared in step (2);

[0120] (4) immersing the modified biochar prepared in step (3) into a mixed solution containing tetraamminecopper sulfate and Mo-EDTA complex, wherein the mass ratio of the modified biochar, tetraamminecopper sulfate and Mo-EDTA complex is 1:0.1:0.1, and stirring the reaction for 1.5 hours to obtain a supported biochar;

[0121] (5) The loaded biochar, perilla biomass extract and animal manure were fully mixed in a mass ratio of 1:40:60, stirred for 25 minutes, and concentrated to obtain a carbon-fixing and nitrogen-retaining biological organic fertilizer.

[0122] The preparation method of the perilla biomass extract comprises: adding 30g of perilla into 1L of water and stirring for 10min, heat-treating the obtained juice for 2.5h at a heat treatment temperature of 90°C to obtain the perilla biomass extract.

[0123] Comparative Example 5

[0124] A carbon-fixing and nitrogen-retaining biological organic fertilizer is prepared by the following preparation method:

[0125] (1) Weighing corn stalks and polyvinyl alcohol resin in a mass ratio of 100:5, crushing the corn stalks and the polyvinyl alcohol resin, mixing them evenly with a solution containing potassium carbonate and potassium hydroxide, and drying them. The dried mixture is placed in a carbonization furnace and carbonized at 750° C. under a nitrogen atmosphere to obtain activated biochar;

[0126] (2) immersing the activated biochar prepared in step (1) into a mixed solution containing H2O2 and dicobalt ethylenediaminetetraacetate, wherein the mass ratio of the activated biochar to the dicobalt ethylenediaminetetraacetate in the mixed solution is 1:0.08, stirring the reaction for 3 hours, and grinding to obtain a hierarchical pore structure product;

[0127] (3) mixing the hierarchical pore structure product prepared in step (2) with the composite bacterial solution and stirring for 1.5 hours to obtain modified biochar;

[0128] The composite bacterial solution is obtained by mixing brown spherical nitrogen-fixing bacteria, ananastomella and Aspergillus niger, wherein the mass ratio of brown spherical nitrogen-fixing bacteria, ananastomella and Aspergillus niger is 2:1.5:1.5, and the total mass of the bacterial species in the composite bacterial solution is 15% of the mass of the hierarchical pore structure product prepared in step (2);

[0129] (4) immersing the modified biochar prepared in step (3) into a mixed solution containing tetraamminecopper sulfate and Mo-EDTA complex, wherein the mass ratio of the modified biochar, tetraamminecopper sulfate and Mo-EDTA complex is 1:0.1:0.1, and stirring the reaction for 1.5 hours to obtain a supported biochar;

[0130] (5) The loaded biochar, nettle biomass extract and animal manure were fully mixed in a mass ratio of 1:40:60, stirred for 25 minutes, and concentrated to obtain a carbon-fixing and nitrogen-retaining biological organic fertilizer.

[0131] The preparation method of the nettle biomass extract comprises: adding 30g of nettle into 1L of water and stirring for 10min, heat-treating the obtained juice for 2.5h at a heat treatment temperature of 90°C to obtain the nettle biomass extract.

[0132] Application examples:

[0133] In the embodiments of this application, the carbon-fixing and nitrogen-preserving bio-organic fertilizers prepared in Examples 1-6 and Comparative Examples 1-5 were tested as follows:

[0134] (1) Test plants: Cherry tomatoes, and the specific variety is Qianxiguo.

[0135] (2) Test grouping: Flowerpots with a diameter of 15 cm and a height of 20 cm were selected. An appropriate amount of soil with basically the same physical and chemical characteristics was filled into each flowerpot. A hole of an appropriate size was dug in the flowerpot, and cherry tomato seedlings with a good growth state and a height of 12 ± 1 cm were transplanted into the flowerpots, with one cherry tomato seedling transplanted into each flowerpot. After mixing 120 g of the carbon-fixing and nitrogen-preserving bio-organic fertilizer evenly with an appropriate amount of soil, it was filled into the flowerpots and gently compacted. The carbon-fixing and nitrogen-preserving bio-organic fertilizers described in the above Examples 1-6 and Comparative Examples 1-5 were applied respectively, with a total of 11 groups set, 5 parallels set in each group, and the average value was taken for each test result. No chemical fertilizers were added throughout the process. The daytime temperature was maintained at about 25 °C, the nighttime temperature was maintained at about 15 °C, the light duration was guaranteed to be 6-8 hours per day, the soil was kept moist, and the watering frequency was adjusted according to the weather and soil humidity.

[0136] Analysis of the growth of cherry tomato plants: After the cherry tomatoes were harvested and picked, samples of cherry tomato plants in each group were collected, and the fresh weight of the above-ground part, the above-ground plant height, and the stem diameter of each pot of cherry tomato plants were measured. The results are recorded in Table 1.

[0137] Measurement of the fresh weight of the above-ground part of cherry tomatoes: The plants were slowly rinsed clean with water, placed in a cool place to dry, and the fresh weight of the above-ground part of the plants was measured separately under an electronic balance. The fresh weight of the above-ground part of each group of plants was recorded, and the average value was calculated.

[0138] Measurement of the above-ground plant height of cherry tomatoes: A tape measure was used to measure the length from the root neck to the top, which is the above-ground plant height. The above-ground plant height of each group was recorded, and the average value was calculated.

[0139] Measurement of the stem diameter of cherry tomato plants: A digital caliper was used to measure the diameter of the plant at 1 cm below the cotyledons, which is the stem diameter of the plant. The stem diameter of each group of plants was recorded, and the average value was calculated.

[0140] Table 1 Influence of the carbon-fixing and nitrogen-preserving bio-organic fertilizer of the present invention on the growth of cherry tomato plants

[0141]

[0142] It can be seen from the results in Table 1:

[0143] Comparison of Example 3 with Comparative Example 1 shows that the present invention selects potassium hydroxide and potassium carbonate as activators to activate corn stalks and polyvinyl alcohol resins rich in oxygen-containing functional groups to prepare activated biochar. Compared with sodium carbonate and sodium hydroxide as activators, potassium hydroxide and potassium carbonate jointly activate corn stalks and polyvinyl alcohol resins, which is more conducive to the load of strains in the composite bacterial liquid on biochar, improves the utilization efficiency of strains, and thus improves the carbon fixation and nitrogen retention capacity of the organic fertilizer finally prepared. Potassium hydroxide and potassium carbonate synergistically activate the biomass system composed of straw and polyvinyl alcohol resin, and can prepare biochar with a hierarchical pore structure, in which the large pores account for a large proportion, ensuring the high loading rate of subsequent strains on the surface of biochar, and appropriate metal cobalt complexes, metal molybdenum and copper complexes, and strains are all loaded in the corresponding pore structure, further improving the pore utilization efficiency in the biochar. In the preparation process of the present invention, the composite bacterial community is first loaded onto the biochar and then the metal molybdenum and copper complex is loaded. Since the molecular size of the metal molybdenum and copper complex is much smaller than the size of the strain in the composite bacterial solution, the complex is combined with the active sites formed between the strains on the biochar, and the active sites on the biochar are fully utilized, the utilization efficiency of the active sites in the biochar is improved, and the loading efficiency of the strains in the composite bacterial solution is guaranteed. By using potassium carbonate and potassium hydroxide as activators, the growth of the plant is better than that of sodium carbonate and sodium hydroxide as activators, and the aboveground fresh weight, aboveground plant height and plant stem thickness are increased to a certain extent, indicating that the biological organic fertilizer using potassium carbonate and potassium hydroxide as activators can better promote the growth of plants.

[0144] By comparing Example 3 with Comparative Example 2, it can be seen that the present invention uses dicobalt ethylenediaminetetraacetate, tetraamminecopper sulfate and Mo-EDTA complex as precursors of metal components, which can ensure the low salinity of organic fertilizer compared to metal inorganic salt components, thereby avoiding the high mortality rate of beneficial soil bacteria, thereby better promoting plant growth.

[0145] It can be seen from the comparison of Example 3 and Comparative Examples 3-4 that the present invention adopts brown ball nitrogen-fixing bacteria, pineapple pantoea and black Aspergillus as composite bacteria, in addition to playing the role of mutual coordination between spontaneous nitrogen-fixing bacteria and degradation bacteria, the species provide energy substances to each other, and the intermediate product of a certain species may be more conducive to the degradation or nitrogen fixation of other species. Compared with the composite bacteria obtained by other species combinations, the composite bacteria recorded in the present invention can make organic fertilizer have better fertility, accelerate the nitrogen fixation process, and improve nitrogen fixation efficiency. Therefore, the composite bacterial liquid selected by the present invention interacts with each other, better promotes the utilization rate of nutrients in organic fertilizer, and provides more abundant nutrition for plant growth.

[0146] As can be seen from the comparison between Example 3 and Comparative Example 5, the perilla biomass extract obtained by using perilla as the raw material of the biomass extract in the present invention can better promote the growth of plants compared with other plant biomass extracts.

[0147] Analysis of soil physical and chemical indexes: After harvesting cherry tomatoes, 200 g of soil was collected from each flower pot to measure the water content, pH value, organic matter, and nitrogen content of the soil. The average value of each group was measured and the results were recorded in Table 2.

[0148] Analysis method for measuring soil water content: 20 g of experimental soil samples were collected and placed in a dry container, weighed to obtain m1 grams. The container containing the collected soil samples was placed in an oven and dried until the weight no longer changed. Then it was taken out and weighed to obtain m2 grams, and its water content was measured.

[0149] Calculation formula for soil water content: W = (m1 - m2) / (m2 - m) * 100%;

[0150] W - Soil water content;

[0151] m - Container (g);

[0152] m1 - Weight of container and wet soil samples (g);

[0153] m2 - Weight of container and dry soil samples (g).

[0154] Analysis method for measuring soil pH value: Take 10 g of soil samples. After air-drying the soil samples, they were ground through a 20-mesh sieve respectively. The soil pH was measured with a pH meter (Leici PHS-25), and the water-soil ratio was 2.5:1.

[0155] Analysis method for measuring soil organic matter content: Take 0.5 g of dried soil samples passing through a 100-mesh sieve hole and place them in a 500 mL conical flask. Add 10 mL of 1 mol / L K2Cr2O7 aqueous solution and gently shake to disperse the soil particles; add 10 mL of concentrated sulfuric acid to the conical flask, shake well, and let stand for 30 min; then add 200 mL of water and 4 drops of o-phenanthroline indicator to the conical flask, and finally titrate to the end point with 0.5 mol / L FeSO4 standard solution. At the same time, a blank determination was made and the low-iron consumption was recorded. Soil organic matter was calculated according to the following formula:

[0156] Soil organic matter g / kg = M(V0 - V) × 0.0057 × 1.4 × 1000 / W

[0157] M - Molar concentration of standard low-iron solution;

[0158] V0 - Consumption of low-iron solution in blank titration, mL;

[0159] V - Consumption of low-iron solution in sample titration, mL;

[0160] W - Oven - dried soil weight, g.

[0161] Determination and analysis method for soil nitrogen content: Agricultural industry standard of the People's Republic of China - Organic fertilizers (NY525 - 2012).

[0162] Table 2 Effects of the carbon - sequestration and nitrogen - preservation bio - organic fertilizer of the present invention on soil physical and chemical indexes

[0163]

[0164] It can be seen from Table 2 that:

[0165] By comparing Example 3 with Comparative Example 1, it can be seen that the present invention selects potassium hydroxide and potassium carbonate together as activators to activate corn straw and polyvinyl alcohol resin with rich oxygen - containing functional groups to prepare activated biochar. Compared with using sodium carbonate and sodium hydroxide as activators, the soil organic matter and nitrogen content of the soil applied with the said organic fertilizer are higher, and the carbon - sequestration and nitrogen - preservation ability of the bio - organic fertilizer is improved.

[0166] By comparing Example 3 with Comparative Example 2, it can be seen that the present invention uses cobalt (II) ethylenediaminetetraacetate, tetraamminecopper (II) sulfate and Mo - EDTA complex as precursors of metal components. Compared with metal inorganic salt components, it can further improve the properties of the soil, thus playing a better promoting role in the growth of plants.

[0167] By comparing Example 3 with Comparative Examples 3 - 4, it can be seen that the present invention uses Azotobacter chroococcum, Pantoea ananatis and Aspergillus niger as composite bacteria. In addition to the mutual synergy between free - living nitrogen - fixing bacteria and degrading bacteria, and the mutual provision of energy substances between bacterial species, it is possible that the intermediate products of a certain bacterial species are more conducive to the degradation or nitrogen fixation of other bacterial species. Compared with the composite bacteria obtained from other bacterial species combinations, the composite bacteria recorded in the present invention can make the organic fertilizer have better fertility, accelerate the nitrogen - fixation process and improve the nitrogen - fixation efficiency. Therefore, the interaction between the selected composite bacterial solutions of the present invention increases the water - retention capacity of the soil, improves the physical and chemical properties of the soil, makes the soil more loose and fertile, and thus is more conducive to the growth of plants.

[0168] By comparing Example 3 with Comparative Example 5, it can be seen that the present invention uses perilla as the raw material of the biomass extract. Compared with other plants, due to the high nitrogen content of perilla, compared with other plants, the nitrogen can have a high nitrogen recovery rate through the preparation of the biomass extract, and then be introduced into the soil via the organic fertilizer of the present invention, which can increase the nitrogen content in the soil and better promote the growth of plants.

[0169] In the present invention, the organic fertilizer can increase the soil organic matter and nitrogen content, adjust the pH value, and the compound bacterial liquid can promote the decomposition of organic matter and the availability of nutrients, and promote the improvement of the soil, so as to facilitate the improvement of soil productivity. At the same time, the organic fertilizer can significantly improve the soil enzyme activity, promote the improvement of soil fertility, and finally achieve the effect of soil conditioning.

[0170] The applicant declares that the technical solution of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent measures for each raw material of the product of the present invention, addition of auxiliary components, selection of specific methods, etc. all fall within the protection scope and disclosure scope of the present invention.

[0171] The above content is only an example and explanation of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should fall within the protection scope of the present invention.

[0172] In addition, it should be noted that in the various specific technical features described in the above specific embodiments, they can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

Claims

1. A method for preparing a carbon-fixing and nitrogen-retaining biological organic fertilizer, characterized in that: The steps include: (1) After crushing corn stalks and polyvinyl alcohol resin by weight, uniformly mixing with a solution containing potassium carbonate and potassium hydroxide, drying, placing the dried mixture in a carbonization furnace, and carbonizing under a nitrogen atmosphere to obtain activated biomass charcoal; the mass ratio of corn stalks to polyvinyl alcohol resin is 100:(1-10), and the carbonization temperature is 700-800°C; （2）将步骤（1）制备得到的活化生物质炭浸入到含有H2O2和乙二胺四乙酸二钴的混合溶液中，搅拌反应2-4h，研磨，得到分级孔结构产物； (3) mixing the hierarchical pore structure product prepared in step (2) with a composite bacterial solution, and stirring for 1-2 hours to obtain modified biochar, wherein the composite bacterial solution is obtained by mixing azotobacter nitrogen-fixing bacteria, Pantoea anacardiae and Aspergillus niger solution; (4) immersing the modified biochar prepared in step (3) into a mixed solution containing tetraamminecopper sulfate and Mo-EDTA complex, stirring and reacting for 1-2 hours to obtain supported biochar; (5) Fully mixing the loaded biochar, perilla biomass extract and animal manure, stirring for 20-30 minutes, and concentrating to obtain a carbon-fixing and nitrogen-retaining biological organic fertilizer; the preparation method of the perilla biomass extract comprises: adding perilla to water and stirring for 10 minutes, heat-treating the obtained juice for 2-3 hours at a heat treatment temperature of 80-120°C to obtain a perilla biomass extract.

2. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of activated biochar to dicobalt ethylenediaminetetraacetate in the mixed solution is 1:(0.01-0.2), and the stirring time is 2 hours.

3. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of brown spherical nitrogen-fixing bacteria, ananastomella and Aspergillus niger is 2: (1-2): (1-2), and the total mass of the bacteria in the composite bacterial liquid is 2-30% of the mass of the hierarchical pore structure product prepared in step (2).

4. The preparation method according to claim 1, characterized in that: The juice is prepared by adding 5-60 grams of perilla to every 1L of water.

5. The preparation method according to claim 1, characterized in that: In step (4), the mass ratio of modified biochar, tetraamminecopper sulfate and Mo-EDTA complex is 1:(0.05-0.2):(0.05-0.2).

6. The preparation method according to claim 1, characterized in that: In step (5), the mass ratio of the supported biochar, the perilla biomass extract and the animal feces is 1:(10-100):(10-100).

7. A carbon-fixing and nitrogen-retaining biological organic fertilizer prepared by the preparation method according to any one of claims 1 to 6.

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