Organic fertilizer for regulating acid soil and preparation method thereof

Abstract

The invention discloses an organic fertilizer for regulating acid soil and a preparation method thereof, and belongs to the technical field of microorganisms. The organic fertilizer is prepared from rice husk biochar, an algae extract, mineral powder, decomposed and fermented pig manure, a microbial agent, urea and an adhesive. According to the invention, the algae extract, the kelp, the seaweed and the ascophyllum nodosum are cooperated to improve the pH value of the soil, increase the nutrient content, improve the soil structure and the like through multiple mechanisms, so that the acidic soil and the crop yield can be improved; the microbial agent composed of the introduced pseudomonas paraxanthomonas and actinomyces nanshan can improve the absorption and utilization of soil nutrients by plants and reduce the aluminum content and the heavy metal content in the soil at the same time. According to the organic fertilizer prepared by the invention, various substances have a synergistic effect, so that the pH value of acid soil is effectively increased, the soil fertility is improved, and the crop yield is increased.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology, specifically relating to an organic fertilizer for regulating acidic soil and its preparation method. Background Technology

[0002] Soil acidification refers to the gradual decrease in soil pH from its original level. It is a process caused by the production of hydrogen ions within the soil and the input of hydrogen ions from the outside, leading to a decrease in soil pH and base saturation. Soil acidification can result in soil compaction, heavy texture, and poor aeration. It can also alter soil biodiversity, reduce the availability of nutrients in the soil, causing nutrient imbalance and decreased fertility. Furthermore, it can activate toxic heavy metals that can harm crops, leading to poor crop growth and development, reduced yield, and decreased crop quality.

[0003] Corn, belonging to the genus *Zea* of the Poaceae family, is an annual herbaceous plant widely cultivated in China. Corn is highly nutritious, with its main components including carbohydrates, protein, fat, vitamins, minerals, and abundant dietary fiber. The dietary fiber in corn helps maintain gut health, while zeaxanthin and carotene have antioxidant properties and can protect eyesight. Furthermore, corn is high in linoleic acid, accounting for over 50% of its fat content; this is an important unsaturated fatty acid beneficial to human health. Besides being widely consumed as an important food crop, corn can also be used as animal feed and industrial raw material. For example, corn stalks and cornmeal can be used as animal feed, while corn can also be used to extract biofuels, produce plastics, and manufacture pharmaceuticals.

[0004] Jilin Province is an important corn production base in my country. However, due to natural soil acidification and excessive fertilizer application, the pH value of various soils in Jilin Province has gradually decreased, showing a trend of soil acidification, which is particularly prominent in the eastern part of Jilin Province. Soil acidification seriously affects the growth and development of corn, leading to reduced yield and quality. Therefore, promoting soil acidification improvement technologies is of great significance for restoring and improving the productivity of acidic soils and ensuring the quantity and quality safety of agricultural products. There are many methods for improving soil acidification, such as implementing soil testing and formula fertilization, increasing the application of organic fertilizers, returning straw to the field, and applying soil conditioners. Summary of the Invention

[0005] The main objective of this invention is to provide an organic fertilizer for regulating acidic soil, which can increase the pH of acidic soil, improve soil fertility, and increase crop yield.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: An organic fertilizer for regulating acidic soil comprises the following raw materials in parts by weight: 40-65 parts rice husk biochar, 14-26 parts algae extract, 12-16 parts mineral powder, 15-25 parts well-rotted pig manure, 5-12 parts microbial inoculant, 10-15 parts urea, and 6-10 parts binder.

[0007] Furthermore, the mineral powder is composed of zeolite calcined at 1100℃, seashells, and magnesium oxide in a mass ratio of 1:1:1.

[0008] Furthermore, the microbial agent is *Pseudomonas paraxanthizobium* at a mass ratio of 1:2. Pseudomonas parafulva ), Nanshan heterocellus actinomycetes ( Actinoalloteichus nanshanensis ).

[0009] Furthermore, the *Pseudomonas paraxanthum* strain has the accession number CGMCC1.15634, with an original accession date of February 25, 2015; the *Heterotomyces nanshanensis* strain has the accession number CGMCC4.5714, with an original accession date of December 5, 2009. All selected strains are available for purchase through the China General Microbiological Culture Collection Center.

[0010] Furthermore, the adhesive is one of bentonite or clay.

[0011] A method for preparing an organic fertilizer for adjusting acidic soil comprises the following steps: (1) Preparation of rice husk biochar: Wash the waste rice husks with clean water, dry them until the moisture content is ≤15%, crush them through a 100-mesh sieve, put them into a reaction vessel, introduce nitrogen to purge the air, raise the temperature to 550℃ within 5 minutes and pyrolyze for 2 hours, cool to room temperature, grind them through a 200-mesh sieve to obtain rice husk biochar. (2) Preparation of microbial inoculants: Pseudomonas paraxanthii and Heterotomyces nanshanensis were cultured in nutrient gravy agar at 30°C and oat agar at 28°C, respectively. The cultures were shaken in an incubator until the bacterial concentration OD600 = 2.0. The two bacteria were then mixed evenly at a mass ratio of 1:2 to obtain a mixed bacterial solution, which was freeze-dried into a freeze-dried powder to obtain a microbial inoculum. (3) Preparation of algal extracts: Kelp, seaweed, and bladderwrack are dried and pulverized to obtain a mixed powder. A complex hydrolytic enzyme solution containing cellulase and sodium alginate lyase is added, and the mixture is enzymatically hydrolyzed at 30°C for 4-6 hours. The mixture is then inactivated at 100°C and cooled to room temperature. The mixture is then set aside for later use. Chloroform and dichloromethane are added to the mixture for extraction. The lower layer is collected, residual organic solvents are removed, and the mixture is dried to obtain the algae extract. (4) Fermentation and composting of pig manure: Mix 50kg of pig manure and 5kg of straw and dry them for 5-6 days, keeping the moisture content at 30%. Dissolve 0.5kg of EM fermentation liquid and 0.5kg of molasses in 5kg of 30℃ warm water, stir well, and spray evenly onto the pig manure mixture while turning it over. Pile it into a manure pile, cover it with plastic film to seal it, and use straw mats to provide appropriate shade. Turn the pile over once or twice in between. When the pig manure temperature drops naturally, turns dark brown, has no odor, and has a soft texture, the composting is complete, and you will get composted pig manure. (5) Granulation: After mixing the rice husk biochar prepared in step (1) with the fermented and decomposed pig manure prepared in step (4), add the microbial agent prepared in step (2), the algae extract prepared in step (3), the mineral powder, urea, and the binder in sequence, stir and mix evenly, dry to a moisture content of 15%, granulate by granulator, screen out 2-5mm particles, and obtain organic fertilizer for adjusting acidic soil.

[0012] Furthermore, in step (3), the mass ratio of kelp, seaweed, and algae is 1:1:1; and in step (3), the mass-volume ratio of the mixed powder and the compound hydrolytic enzyme solution is 1:2 (kg / L).

[0013] Furthermore, the compound hydrolytic enzyme solution contains 18-20 g / L of cellulase and 5-8 g / L of sodium alginate lyase.

[0014] The organic fertilizer application rate for regulating acidic soil in this invention is 500 kg / mu.

[0015] In this invention, kelp, seaweed, and *Alternaria alternifolia* synergistically improve acidic soil through multiple mechanisms, including increasing soil pH, enhancing nutrient content, improving soil structure, and promoting microbial activity, thereby contributing to improved soil fertility and crop yield. Firstly, these three algae act as fertilizers, replenishing macro- and micronutrients in the soil, improving soil structure, and increasing soil fertility. Secondly, kelp, seaweed, and *Alternaria alternifolia* are rich in alginic acid, a natural carbohydrate that can be used to produce biodegradable hydrogels. The degradation process enriches the soil, exhibits excellent water retention capacity, and can absorb large amounts of water, thus improving the soil's physical properties. Furthermore, the three algae contain polysaccharide compounds that stabilize the topsoil, prevent erosion, promote microbial activity, create favorable environmental conditions, promote root growth, and improve soil texture. In addition, the active substances contained in these three materials increase soil aeration, promote the formation of soil aggregates, increase soil biological activity, and accelerate nutrient release and utilization.

[0016] The mineral powder in this invention consists of zeolite calcined at 1100℃, seashells, and magnesium oxide. Seashell powder is rich in CaO, which reacts with water to form calcium hydroxide, increasing the soil pH. When the soil pH rises, aluminum ions combine with hydroxide ions to form aluminum hydroxide precipitate, thereby reducing the activity of aluminum ions in the soil. Seashell powder also increases the organic matter content of the soil, enhancing soil fertility and promoting plant growth. Magnesium oxide is also an alkaline substance, further neutralizing soil acidity and increasing the soil pH. Zeolite reduces the concentration of exchangeable and hydrolyzable acids in the soil. Simultaneously, zeolite adsorbs heavy metal ions in the soil, reducing their bioavailability and minimizing harm to crops and the environment. Furthermore, zeolite powder has ion exchange capacity, providing nutrients needed by plants and reducing fertilizer loss.

[0017] The microbial agent in this invention consists of *Pseudomonas paraxanthum* and *Heterocarpus nanshanense*. *Pseudomonas paraxanthum* can regulate soil pH, promote soil aggregate formation, and improve soil physical properties. These characteristics give it a good regulating effect in acidic soils, increasing soil fertility, and it also shows good efficacy in the bioremediation of heavy metal-contaminated soils. Furthermore, *Pseudomonas paraxanthum* also possesses plant growth-promoting functions, nitrogen fixation, phosphorus solubilization, and iron carrier secretion capabilities, which help improve plant absorption and utilization of soil nutrients. *Heterocarpus nanshanense* can promote the dissolution of calcium phosphate under acidic soil conditions, improving the availability of phosphorus in the soil. *Heterocarpus nanshanense* can also degrade insoluble nutrients by secreting extracellular substances, promoting plant absorption, and simultaneously catalyzing the redox process of heavy metals. In addition, the synergistic effect of the two strains can adsorb aluminum-containing minerals in the soil, significantly reducing the aluminum content in the soil.

[0018] Beneficial effects This invention utilizes algal extracts containing various active ingredients. Kelp, seaweed, and *Alternaria alternifolia* synergistically improve acidic soil through multiple mechanisms, including increasing soil pH, enhancing nutrient content, improving soil structure, and enriching the microbial community, thereby contributing to improved acidic soil and increased crop yield. A microbial inoculant composed of *Pseudomonas paraxanthum* and *Heterothecia nanshanensis* can improve plant absorption and utilization of soil nutrients while reducing aluminum and heavy metal content in the soil. The synergistic effect of various substances used in the organic fertilizer prepared by this invention effectively increases the pH of acidic soil, improves soil fertility, and increases crop yield. Detailed Implementation

[0019] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0020] Example 1 An organic fertilizer for regulating acidic soil comprises the following raw materials in parts by weight: 40 parts rice husk biochar, 14 parts algae extract, 12 parts mineral powder, 15 parts well-rotted pig manure, 5 parts microbial inoculant, 10 parts urea, and 6 parts binder.

[0021] The mineral powder is composed of zeolite, seashells, and magnesium oxide calcined at 1100℃ in a mass ratio of 1:1:1.

[0022] The microbial agent is Pseudomonas paraxanthum and Heterotomyces nanshanensis in a mass ratio of 1:2.

[0023] The preservation number of *Pseudomonas paraxanthum* is CGMCC1.15634; the preservation number of *Heterotomyces nanshanensis* is CGMCC4.5714.

[0024] The adhesive is bentonite.

[0025] A method for preparing an organic fertilizer for adjusting acidic soil comprises the following steps: (1) Preparation of rice husk biochar: Wash the waste rice husks with clean water, dry them until the moisture content is ≤15%, crush them through a 100-mesh sieve, put them into a reaction vessel, introduce nitrogen to purge the air, raise the temperature to 550℃ within 5 minutes and pyrolyze for 2 hours, cool to room temperature, grind them through a 200-mesh sieve to obtain rice husk biochar. (2) Preparation of microbial inoculants: Pseudomonas paraxanthii and Heterotomyces nanshanensis were cultured in nutrient gravy agar at 30°C and oat agar at 28°C, respectively. The cultures were shaken in an incubator until the bacterial concentration OD600 = 2.0. The two bacteria were then mixed evenly at a mass ratio of 1:2 to obtain a mixed bacterial solution, which was freeze-dried into a freeze-dried powder to obtain a microbial inoculum. (3) Preparation of algal extracts: Kelp, seaweed, and bladderwort were dried and pulverized to obtain a mixed powder. A complex hydrolytic enzyme solution containing cellulase and sodium alginate lyase was added, and the mixture was enzymatically hydrolyzed at 30°C for 4 hours. The mixture was then inactivated at 100°C and cooled to room temperature. The mixture was then set aside for later use. Chloroform and dichloromethane were added to the mixture for extraction. The lower layer of the solution was collected, residual organic solvents were removed, and the mixture was dried to obtain the algae extract. (4) Fermentation and composting of pig manure: Mix 50kg of pig manure and 5kg of straw and dry them for 5-6 days, keeping the moisture content at 30%. Dissolve 0.5kg of EM fermentation liquid and 0.5kg of molasses in 5kg of 30℃ warm water, stir well, and spray evenly onto the pig manure mixture while turning it over. Pile it into a manure pile, cover it with plastic film to seal it, and use straw mats to provide appropriate shade. Turn the pile over once or twice in between. When the pig manure temperature drops naturally, turns dark brown, has no odor, and has a soft texture, the composting is complete, and you will get composted pig manure. (5) Granulation: After mixing the rice husk biochar prepared in step (1) with the fermented and decomposed pig manure prepared in step (4), add the microbial agent prepared in step (2), the algae extract prepared in step (3), the mineral powder, urea, and the binder in sequence, stir and mix evenly, dry to a moisture content of 15%, granulate by granulator, screen out 2-5mm particles, and obtain organic fertilizer for adjusting acidic soil.

[0026] In step (3), the mass ratio of kelp, seaweed, and algae is 1:1:1; in step (3), the mass-volume ratio of the mixed powder and the compound hydrolytic enzyme solution is 1:2 (kg / L).

[0027] The compound hydrolytic enzyme solution contains 18 g / L of cellulase and 5 g / L of sodium alginate lyase.

[0028] Example 2 An organic fertilizer for regulating acidic soil comprises the following raw materials in parts by weight: 50 parts rice husk biochar, 19 parts algae extract, 14 parts mineral powder, 20 parts well-rotted pig manure, 8 parts microbial inoculant, 12 parts urea, and 8 parts binder.

[0029] The mineral powder is composed of zeolite, seashells, and magnesium oxide calcined at 1100℃ in a mass ratio of 1:1:1.

[0030] The microbial agent is Pseudomonas paraxanthum and Heterotomyces nanshanensis in a mass ratio of 1:2.

[0031] The preservation number of *Pseudomonas paraxanthum* is CGMCC1.15634; the preservation number of *Heterotomyces nanshanensis* is CGMCC4.5714.

[0032] The adhesive is clay.

[0033] A method for preparing an organic fertilizer for adjusting acidic soil comprises the following steps: (1) Preparation of rice husk biochar: Wash the waste rice husks with clean water, dry them until the moisture content is ≤15%, crush them through a 100-mesh sieve, put them into a reaction vessel, introduce nitrogen to purge the air, raise the temperature to 550℃ within 5 minutes and pyrolyze for 2 hours, cool to room temperature, grind them through a 200-mesh sieve to obtain rice husk biochar. (2) Preparation of microbial inoculants: Pseudomonas paraxanthii and Heterothecia nanshanensis were cultured in nutrient gravy agar at 30°C and oat agar at 28°C, respectively. The cultures were shaken in an incubator until the bacterial concentration OD600 = 2.0. The two bacteria were then mixed evenly at a mass ratio of 1:2 to obtain a mixed bacterial solution, which was then freeze-dried into a freeze-dried powder to obtain a microbial inoculum. (3) Preparation of algal extracts: Kelp, seaweed, and bladderwort were dried and pulverized to obtain a mixed powder. A complex hydrolytic enzyme solution containing cellulase and sodium alginate lyase was added, and the mixture was enzymatically hydrolyzed at 30°C for 5 hours. The mixture was then inactivated at 100°C and cooled to room temperature. The mixture was then set aside for later use. Chloroform and dichloromethane were added to the mixture for extraction. The lower layer of the solution was collected, and residual organic solvents were removed. After drying, the algae extract was obtained. (4) Fermentation and composting of pig manure: Mix 50kg of pig manure and 5kg of straw and dry them for 5-6 days, keeping the moisture content at 30%. Dissolve 0.5kg of EM fermentation liquid and 0.5kg of molasses in 5kg of 30℃ warm water, stir well, and spray evenly onto the pig manure mixture while turning it over. Pile it into a manure pile, cover it with plastic film to seal it, and use straw mats to provide appropriate shade. Turn the pile over once or twice in between. When the pig manure temperature drops naturally, turns dark brown, has no odor, and has a soft texture, the composting is complete, and you will get composted pig manure. (5) Granulation: After mixing the rice husk biochar prepared in step (1) with the fermented and decomposed pig manure prepared in step (4), add the microbial agent prepared in step (2), the algae extract prepared in step (3), the mineral powder, urea, and the binder in sequence, stir and mix evenly, dry to a moisture content of 15%, granulate by granulator, screen out 2-5mm particles, and obtain organic fertilizer for adjusting acidic soil.

[0034] In step (3), the mass ratio of kelp, seaweed, and algae is 1:1:1; in step (3), the mass-volume ratio of the mixed powder and the compound hydrolytic enzyme solution is 1:2 (kg / L).

[0035] The compound hydrolytic enzyme solution contains 19 g / L of cellulase and 6 g / L of sodium alginate lyase.

[0036] Example 3 An organic fertilizer for regulating acidic soil comprises the following raw materials in parts by weight: 65 parts rice husk biochar, 26 parts algae extract, 16 parts mineral powder, 25 parts well-rotted and fermented pig manure, 12 parts microbial inoculant, 15 parts urea, and 10 parts binder.

[0037] The mineral powder is composed of zeolite, seashells, and magnesium oxide calcined at 1100℃ in a mass ratio of 1:1:1.

[0038] The microbial agent is Pseudomonas paraxanthum and Heterotomyces nanshanensis in a mass ratio of 1:2.

[0039] The preservation number of *Pseudomonas paraxanthum* is CGMCC1.15634; the preservation number of *Heterotomyces nanshanensis* is CGMCC4.5714.

[0040] The adhesive is bentonite.

[0041] A method for preparing an organic fertilizer for adjusting acidic soil comprises the following steps: (1) Preparation of rice husk biochar: Wash the waste rice husks with clean water, dry them until the moisture content is ≤15%, crush them through a 100-mesh sieve, put them into a reaction vessel, introduce nitrogen to purge the air, raise the temperature to 550℃ within 5 minutes and pyrolyze for 2 hours, cool to room temperature, grind them through a 200-mesh sieve to obtain rice husk biochar. (2) Preparation of microbial inoculants: Pseudomonas paraxanthii and Heterothecia nanshanensis were cultured in nutrient gravy agar at 30°C and oat agar at 28°C, respectively. The cultures were shaken in an incubator until the bacterial concentration OD600 = 2.0. The two bacteria were then mixed evenly at a mass ratio of 1:2 to obtain a mixed bacterial solution, which was then freeze-dried into a freeze-dried powder to obtain a microbial inoculum. (3) Preparation of algal extracts: Kelp, seaweed, and bladderwort were dried and pulverized to obtain a mixed powder. A complex hydrolytic enzyme solution containing cellulase and sodium alginate lyase was added, and the mixture was enzymatically hydrolyzed at 30°C for 6 hours. The mixture was then inactivated at 100°C and cooled to room temperature. The mixture was then set aside for later use. Chloroform and dichloromethane were added to the mixture for extraction. The lower layer of the solution was collected, and residual organic solvents were removed. After drying, the algae extract was obtained. (4) Fermentation and composting of pig manure: Mix 50kg of pig manure and 5kg of straw and dry them for 5-6 days, keeping the moisture content at 30%. Dissolve 0.5kg of EM fermentation liquid and 0.5kg of molasses in 5kg of 30℃ warm water, stir well, and spray evenly onto the pig manure mixture while turning it over. Pile it into a manure pile, cover it with plastic film to seal it, and use straw mats to provide appropriate shade. Turn the pile over once or twice in between. When the pig manure temperature drops naturally, turns dark brown, has no odor, and has a soft texture, the composting is complete, and you will get composted pig manure. (5) Granulation: After mixing the rice husk biochar prepared in step (1) with the fermented and decomposed pig manure prepared in step (4), add the microbial agent prepared in step (2), the algae extract prepared in step (3), the mineral powder, urea, and the binder in sequence, stir and mix evenly, dry to a moisture content of 15%, granulate by granulator, screen out 2-5mm particles, and obtain organic fertilizer for adjusting acidic soil.

[0042] In step (3), the mass ratio of kelp, seaweed, and algae is 1:1:1; in step (3), the mass-volume ratio of the mixed powder and the compound hydrolytic enzyme solution is 1:2 (kg / L).

[0043] The compound hydrolytic enzyme solution contains 20 g / L of cellulase and 8 g / L of sodium alginate lyase.

[0044] Comparative Example 1 An organic fertilizer for regulating acidic soil comprises the following raw materials in parts by weight: 65 parts rice husk biochar, 26 parts algae extract, 16 parts mineral powder, 25 parts well-rotted and fermented pig manure, 12 parts microbial inoculant, 15 parts urea, and 10 parts binder.

[0045] The mineral powder is composed of zeolite, seashells, and magnesium oxide calcined at 1100℃ in a mass ratio of 1:1:1.

[0046] The microbial agent is Pseudomonas paraxanthum and Heterotomyces nanshanensis in a mass ratio of 1:1.

[0047] The preservation number of *Pseudomonas paraxanthum* is CGMCC1.15634; the preservation number of *Heterotomyces nanshanensis* is CGMCC4.5714.

[0048] The adhesive is bentonite.

[0049] A method for preparing an organic fertilizer for adjusting acidic soil comprises the following steps: (1) Preparation of rice husk biochar: Wash the waste rice husks with clean water, dry them until the moisture content is ≤15%, crush them through a 100-mesh sieve, put them into a reaction vessel, introduce nitrogen to purge the air, raise the temperature to 550℃ within 5 minutes and pyrolyze for 2 hours, cool to room temperature, grind them through a 200-mesh sieve to obtain rice husk biochar. (2) Preparation of microbial inoculants: Pseudomonas paraxanthii and Heterotomyces nanshanensis were cultured in nutrient gravy agar at 30°C and oat agar at 28°C, respectively. The cultures were shaken in an incubator until the bacterial concentration OD600 = 2.0. The two bacteria were then mixed evenly at a mass ratio of 1:1 to obtain a mixed bacterial solution, which was then freeze-dried into a freeze-dried powder to obtain a microbial inoculum. (3) Preparation of algal extracts: Kelp, seaweed, and bladderwort were dried and pulverized to obtain a mixed powder. A complex hydrolytic enzyme solution containing cellulase and sodium alginate lyase was added, and the mixture was enzymatically hydrolyzed at 30°C for 6 hours. The mixture was then inactivated at 100°C and cooled to room temperature. The mixture was then set aside for later use. Chloroform and dichloromethane were added to the mixture for extraction. The lower layer of the solution was collected, and residual organic solvents were removed. After drying, the algae extract was obtained. (4) Fermentation and composting of pig manure: Mix 50kg of pig manure and 5kg of straw and dry them for 5-6 days, keeping the moisture content at 30%. Dissolve 0.5kg of EM fermentation liquid and 0.5kg of molasses in 5kg of 30℃ warm water, stir well, and spray evenly onto the pig manure mixture while turning it over. Pile it into a manure pile, cover it with plastic film to seal it, and use straw mats to provide appropriate shade. Turn the pile over once or twice in between. When the pig manure temperature drops naturally, turns dark brown, has no odor, and has a soft texture, the composting is complete, and you will get composted pig manure. (5) Granulation: After mixing the rice husk biochar prepared in step (1) with the fermented and decomposed pig manure prepared in step (4), add the microbial agent prepared in step (2), the algae extract prepared in step (3), the mineral powder, urea, and the binder in sequence, stir and mix evenly, dry to a moisture content of 15%, granulate by granulator, screen out 2-5mm particles, and obtain organic fertilizer for adjusting acidic soil.

[0050] In step (3), the mass ratio of kelp, seaweed, and algae is 1:1:1; in step (3), the mass-volume ratio of the mixed powder and the compound hydrolytic enzyme solution is 1:2 (kg / L).

[0051] The compound hydrolytic enzyme solution contains 20 g / L of cellulase and 8 g / L of sodium alginate lyase.

[0052] Compared with Example 3, the mass ratio of *Pseudomonas paraxanthum* and *Heterotomyces nanshanensis* used in this comparative example is 1:1, and the other raw materials and steps are the same as in Example 3.

[0053] Comparative Example 2 Compared with Example 3, the mass ratio of *Pseudomonas paraxanthum* and *Heterotomyces nanshanensis* used in this comparative example is 2:1, and the other raw materials and steps are the same as in Example 3.

[0054] Comparative Example 3 Compared with Example 3, the microbial agent used in this comparative example is only *Pseudomonas paraxanthum*, while the other raw materials and steps are the same as in Example 3.

[0055] Comparative Example 4 Compared with Example 3, the microbial agent used in this comparative example is only *Heterotomyces nanshanensis*, while the other raw materials and steps are the same as in Example 3.

[0056] Comparative Example 5 Compared with Example 3, the algae extract in this comparative example is seaweed and algae in a mass ratio of 1:1, and the other raw materials and steps are the same as in Example 3.

[0057] Comparative Example 6 Compared with Example 3, the algae extract in this comparative example is kelp and algae in a mass ratio of 1:1, and the other raw materials and steps are the same as in Example 3.

[0058] Comparative Example 7 Compared with Example 3, the algae extract in this comparative example is kelp and seaweed in a mass ratio of 1:1, and the other raw materials and steps are the same as in Example 3.

[0059] Performance testing Experimental Location: The experiment was conducted in Hailong Town, Meihekou City, Jilin Province. This area is located in southeastern Jilin Province, belonging to the mid-temperate humid climate zone, with an average annual temperature of 5.5℃, an annual sunshine duration of 2200 h, a frost-free period of 146 days, and an average annual precipitation of 620 mm. At the start of the experiment, the basic nutrient status of the topsoil (0~20 cm) was as follows: pH 4.6, organic matter 16.71 g / kg, total nitrogen 1.74 g / kg, available phosphorus 87.52 mg / kg, available potassium 153.33 mg / kg, aluminum ions 754 mg / Kg, available cadmium 0.146 mg / Kg, available lead 12.4 mg / Kg, and available mercury 0.075 mg / Kg.

[0060] Experimental Treatments: The experimental field was divided into 10 portions, and the fertilizers obtained in Examples 1-3 and Comparative Examples 1-7 of this invention were applied to the experimental fields respectively. Before planting corn, the organic fertilizers from the examples and comparative examples were applied to the corresponding treatments at a rate of 500 kg / mu. During land preparation, the organic fertilizers were mixed evenly with the topsoil. The area of ​​each experimental field was 30 m². 2 Repeat 3 times, with each group arranged randomly.

[0061] Soil tests were conducted on the original soil before fertilization and on the experimental fields one month after the application of each group of organic fertilizers. Six sampling points were randomly selected from each experimental field. Soil samples were collected from the 20cm vertical soil layer at each sampling point. After mixing, the contents of soil pH, organic matter, total nitrogen, available phosphorus, available potassium, aluminum ions, available cadmium, available lead, and available mercury were tested and the average values ​​were calculated.

[0062] Detection method: Soil pH: determined using the potentiometric method for determining soil pH (HJ 962-2018); Organic matter: determined using the potassium dichromate titration method; Total nitrogen: determined using the semi-micro Kjeldahl method; Available phosphorus: determined using the sodium bicarbonate extraction spectrophotometric method; Available potassium: determined using the flame photometric method; Aluminum ions: determined using the potassium chloride exchange-neutralization titration method; Available cadmium and lead: determined using atomic absorption spectrometry as recorded in GB / T23739-2009, with DTPA used to extract lead and cadmium from the soil; Available mercury: determined according to the "Journal of Light Industry, 2018, Vol. 1: Rapid Detection of Available Mercury in Soil".

[0063] The test results are shown in Table 1-2: Table 1 Soil Property Testing Table Table 2 Soil Property Testing Table Field trials The experiment was conducted in Hailong Town, Meihekou City, Jilin Province. This area is located in southeastern Jilin Province and belongs to the mid-temperate humid climate zone. The average annual temperature is 5.5 ℃, the annual sunshine duration is 2200 h, the frost-free period is 146 d, and the average annual precipitation is 620 mm.

[0064] Experimental treatments: The experimental field was divided into 10 portions, and the fertilizers obtained in Examples 1-3 and Comparative Examples 1-7 of this invention were applied to each treatment group, respectively. The organic fertilizer application rate for each treatment group was 500 kg / mu, and the planting area for each group was 30 m². 2 The experiment was repeated three times, with each group randomly arranged. The maize variety used was Xianyu 335. Field management was conducted according to conventional production field practices. Other field management practices were also conducted according to conventional production field practices. The average yield, number of ears harvested, 100-kernel weight, and harvest index of maize for each group were statistically analyzed. The results are shown in Table 3. Table 3. Corn Planting and Harvesting Situation As shown in Tables 1 and 2, compared with the organic fertilizers of Comparative Examples 1-7, the organic fertilizers prepared in Examples 1-3 can effectively increase the pH of acidic soil, improve soil fertility, reduce the aluminum content and various heavy metal content in acidic soil, and improve the absorption and utilization of soil nutrients by plants. Furthermore, Table 3 shows that the application of the organic fertilizers prepared in this invention can increase the number of ears and the weight of 100 kernels in corn, resulting in fuller kernels and thus increasing corn yield.

[0065] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. An organic fertilizer for regulating acidic soil, characterized in that, The raw materials include the following parts by weight: 40-65 parts rice husk biochar, 14-26 parts algae extract, 22-26 parts mineral powder, 15-25 parts decomposed and fermented pig manure, 5-12 parts microbial inoculant, 10-15 parts urea, and 6-10 parts binder.

2. The organic fertilizer for regulating acidic soil according to claim 1, characterized in that, The mineral powder is composed of zeolite, seashells, and magnesium oxide calcined at 1100℃ in a mass ratio of 1:1:

1.

3. The organic fertilizer for regulating acidic soil according to claim 1, characterized in that, The microbial agent is *Pseudomonas paraxanthii* at a mass ratio of 1:

2. Pseudomonas parafulva ), Nanshan heterocellus actinomycetes ( Actinoalloteichus nanshanensis ).

4. The organic fertilizer for regulating acidic soil according to claim 3, characterized in that, The preservation number of *Pseudomonas paraxanthum* is CGMCC1.15634; the preservation number of *Heterotomyces nanshanensis* is CGMCC4.5714.

5. The organic fertilizer for regulating acidic soil according to claim 1, characterized in that, The adhesive is one of bentonite and clay.

6. The method for preparing organic fertilizer for adjusting acidic soil according to any one of claims 1-5, characterized in that, Prepared by the following steps: (1) Preparation of rice husk biochar: Wash the waste rice husks with clean water, dry them until the moisture content is ≤15%, crush them through a 100-mesh sieve, put them into a reaction vessel, introduce nitrogen to purge the air, raise the temperature to 550℃ within 5 minutes and pyrolyze for 2 hours, cool to room temperature, grind them through a 200-mesh sieve to obtain rice husk biochar. (2) Preparation of microbial inoculants: Pseudomonas paraxanthii and Heterothecia nanshanensis were cultured in nutrient gravy agar at 30°C and oat agar at 28°C, respectively. The cultures were shaken in an incubator until the bacterial concentration OD600 = 2.

0. The two bacteria were then mixed evenly at a mass ratio of 1:2 to obtain a mixed bacterial solution, which was then freeze-dried into a freeze-dried powder to obtain a microbial inoculum. (3) Preparation of algal extracts: Kelp, seaweed, and bladderwrack are dried and pulverized to obtain a mixed powder. A complex hydrolytic enzyme solution containing cellulase and sodium alginate lyase is added, and the mixture is enzymatically hydrolyzed at 30°C for 4-6 hours. The mixture is then inactivated at 100°C and cooled to room temperature. The mixture is then set aside for later use. Chloroform and dichloromethane are added to the mixture for extraction. The lower layer is collected, residual organic solvents are removed, and the mixture is dried to obtain the algae extract. (4) Fermentation and composting of pig manure: Mix 50kg of pig manure and 5kg of straw and dry them for 5-6 days, keeping the moisture content at 30%. Dissolve 0.5kg of EM fermentation liquid and 0.5kg of molasses in 5kg of 30℃ warm water, stir well, and spray evenly onto the pig manure mixture while turning it over. Pile it into a manure pile, cover it with plastic film to seal it, and use straw mats to provide appropriate shade. Turn the pile over once or twice in between. When the pig manure temperature drops naturally, turns blackish-brown, has no odor, and has a soft texture, the composting is complete, and you will get composted pig manure. (5) Granulation: After mixing the rice husk biochar prepared in step (1) with the fermented and decomposed pig manure prepared in step (4), add the microbial agent prepared in step (2), the algae extract prepared in step (3), the mineral powder, urea, and the binder in sequence, stir and mix evenly, dry to a moisture content of 15%, granulate by granulator, screen out 2-5mm particles, and obtain organic fertilizer for adjusting acidic soil.

7. The method for preparing organic fertilizer for adjusting acidic soil according to claim 6, characterized in that, In step (3), the mass ratio of kelp, seaweed, and algae is 1:1:1; in step (3), the mass-volume ratio of the mixed powder and the compound hydrolytic enzyme solution is 1:2 (kg / L).

8. The method for preparing organic fertilizer for adjusting acidic soil according to claim 7, characterized in that, The compound hydrolytic enzyme solution contains 18-20 g / L of cellulase and 5-8 g / L of sodium alginate lyase.

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