Biological organic fertilizer for heavy metal contaminated soil remediation and preparation method thereof

Abstract

The invention provides a biological organic fertilizer for heavy metal contaminated soil remediation and a preparation method thereof, and belongs to the technical field of fertilizers, the biological organic fertilizer comprises the following raw materials by weight: 15-20 parts of chicken manure, 24-29 parts of pig manure, 3-9 parts of wormcast, 11-15 parts of soybean meal, 20-25 parts of modified charcoal, 16-21 parts of an extraction residue fermentation product, and 4-12 parts of a microbial agent. The prepared biological organic fertilizer for heavy metal contaminated soil remediation can improve the pH value of soil, can continuously and effectively improve the physical and chemical properties of the soil, improves the biological activity of the soil, can effectively reduce the content level of heavy metal elements in the soil, achieves all-around adjustment of the soil environment, and promotes soybean income increase.

Description

Technical Field

[0001] The invention belongs to the technical field of organic fertilizers, and in particular relates to a biological organic fertilizer for repairing heavy metal polluted soil and a preparation method thereof. Background Art

[0002] Heavy metal pollution in farmland is mainly an environmental pollution phenomenon caused by excessive accumulation of waste containing heavy metals in the soil. The main heavy metals involved in this type of pollution include elements such as mercury, cadmium, lead, chromium and metalloid arsenic with significant biological toxicity, as well as elements such as zinc, copper, and nickel with certain toxicity. Once these heavy metals enter the farmland soil, they will not only affect the ecological balance of the soil itself, but may also affect human health through the food chain, causing serious consequences. Therefore, the prevention, control and management of heavy metal pollution in farmland soil is particularly important. This not only concerns the quality and safety of crops, but also directly affects people's dietary health and the sustainable development of the ecological environment.

[0003] Bio-organic fertilizer has significant advantages in treating heavy metal pollution in soil. It can not only effectively reduce the toxicity of heavy metals, but also improve soil quality and promote crop growth. It is an environmentally friendly soil remediation technology worthy of promotion and application.

[0004] At present, there are many bio-organic fertilizers for the remediation of heavy metal contaminated soil. Although bio-organic fertilizers have shown many advantages in the treatment of soil heavy metal pollution, they still face some technical and implementation challenges in practical application: (1) Unstable heavy metal fixation effect: Although bio-organic fertilizers can fix heavy metals by forming chelates or complexes, this fixation effect may be affected by environmental factors such as soil pH, temperature, and humidity, resulting in the reactivation of heavy metals, thereby weakening the remediation effect. (2) Selection and proportion of bio-organic fertilizers: Different types of bio-organic fertilizers have different adsorption and fixation capabilities for heavy metals. It is necessary to select the appropriate fertilizer type and reasonable application ratio according to the specific pollution situation of the soil and the needs of crops, which increases the difficulty of practical operation. (3) Maintenance of microbial activity: Beneficial microorganisms in bio-organic fertilizers are sensitive to environmental conditions. If the soil conditions are not suitable (such as extreme pH, drought or excessive humidity), the survival rate and activity of microorganisms may be affected, thereby affecting the remediation effect. (4) Limited heavy metal removal efficiency: Bio-organic fertilizers mainly reduce the biological effectiveness of heavy metals through fixation, rather than completely removing heavy metals from the soil. This means that once environmental conditions change, the fixed heavy metals may be released again, causing secondary pollution. (5) Uncertainty of long-term effects: The remediation of soil heavy metal pollution by bio-organic fertilizers is a long-term process, and its long-term effects and stability still need further research and verification, especially under different climatic conditions and in different types of soil.

[0005] Chinese patent CN113480364B discloses an organic fertilizer for treating heavy metal pollution and a preparation method thereof, which is composed of 10-20 parts by weight of fulvic acid, 5-10 parts by weight of vermiculite, 5-10 parts by weight of kaolinite, 10-20 parts by weight of biochar, 5-10 parts by weight of potassium fulvic acid, 15-30 parts by weight of organic fertilizer and 5-12 parts by weight of microbial agent. This method can be applied to the field of heavy metal removal. However, the heavy metal removal efficiency is limited and the yield-increasing effect on soybeans is not good.

[0006] Therefore, there is an urgent need for a biological organic fertilizer for remediation of heavy metal contaminated soil and a preparation method thereof. Summary of the invention

[0007] The purpose of the present invention is to provide a biological organic fertilizer for remediation of heavy metal contaminated soil and a preparation method thereof.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A biological organic fertilizer for remediation of heavy metal contaminated soil, comprising the following raw materials in weight fractions: 15-20 parts of chicken manure, 24-29 parts of pig manure, 3-9 parts of earthworm manure, 11-15 parts of soybean meal, 20-25 parts of modified biochar, 16-21 parts of extraction residue fermentation product, and 4-12 parts of microbial agent;

[0010] The method for preparing the extraction residue fermentation product comprises the following steps:

[0011] (1) crushing the residue extracted from the bark of Taxus cuspidata into particles with a particle size of 0.2-0.8 cm to obtain a fermentation raw material;

[0012] (2) Spraying bacterial liquid onto the fermentation raw materials, mixing them evenly, and then stacking and fermenting them at room temperature. The piles are turned over every 7-10 days, and the fermentation process is continued for 4-6 weeks. The fermentation process is then air-dried to obtain an extraction residue fermentation product.

[0013] Furthermore, the weight percentage of the bacterial liquid to the fermentation raw material is 0.4-0.7%.

[0014] Furthermore, the method for preparing the bacterial solution comprises the following steps:

[0015] (1) The three strains were inoculated on slant culture medium respectively, and static cultured and activated at 30-35° C., and three slant cultured bacterial strains were obtained after the colonies covered the slant; the three strains were: Halomonas marinum, Aspergillus niger, and Trichoderma harzianum;

[0016] (2) inoculating the three slant cultured bacteria into peptone liquid culture medium respectively, and culturing at 35-38° C. and 150-170 r / min with shaking for 20-25 h to obtain seed liquid of Halomonas marinum, seed liquid of Aspergillus niger, and seed liquid of Trichoderma harzianum respectively;

[0017] (3) Inoculating the seed liquid of Halomonas marinum, the seed liquid of Aspergillus niger and the seed liquid of Trichoderma harzianum into the same fermentation medium for aerobic fermentation to obtain a bacterial liquid.

[0018] Furthermore, in the step (3), the sea salt mononas seed solution is inoculated into the fermentation medium at an inoculation amount of 1.4%-1.8% by weight; the Aspergillus niger seed solution is inoculated into the fermentation medium at an inoculation amount of 1.3%-1.6% by weight, and the Trichoderma harzianum seed solution is inoculated into the fermentation medium at an inoculation amount of 0.6%-0.9% by weight.

[0019] Paclitaxel extracted from the bark of Taxus cuspidata (T. CUSPIDATA STEBIUCC (Bark)) is an important anticancer drug, and the bark residue after the extraction of paclitaxel causes environmental pollution as waste. The present invention uses the bark residue after the extraction of paclitaxel as a raw material and ferments it with a specific bacterial solution, which can improve the organic matter content of saline-alkali land. Analysis shows that the bark residue after the extraction of paclitaxel contains rich organic matter, which can be converted into high-quality organic fertilizer after fermentation; organic acids, amino acids, polysaccharides and other substances produced during the fermentation process can improve the physical and chemical properties of the soil and increase the organic matter content of the soil. Specific bacterial solution can promote the decomposition of organic matter and generate more beneficial metabolites. These microorganisms can also inhibit the growth of harmful microorganisms and improve the biological activity of the soil; the organic acids produced during the fermentation process can react with the salt in the soil to form more stable compounds and reduce the salt content of the soil. At the same time, the activity of the strains in the microbial inoculant can also be improved.

[0020] Furthermore, the microbial agent includes Pseudomonas paraxanthomonas, Bacillus subtilis and Bacillus amyloliquefaciens.

[0021] Furthermore, the bacterial activity of Pseudomonas paraxanthinus in the microbial inoculant is 10 9 CFU / g-10 10 CFU / g; the bacterial activity of Bacillus subtilis in the microbial agent is 10 8 CFU / g-10 9 CFU / g; the bacterial activity of Bacillus amyloliquefaciens in the mixed solution is 10 6 CFU / g-10 7 CFU / g.

[0022] The present invention attempts to use Pseudomonas paraflavus with good salt-alkali tolerance to improve the content level of heavy metal elements in the soil, but the effect is not ideal. The present invention prepares a microbial agent by adding three composite strains, which can reduce the content level of heavy metal elements in the soil. Mainly, the three microbial bacteria can increase the organic matter content of the soil and improve the water and fertilizer retention capacity of the soil through synergistic action. The good soil structure helps to reduce the migration and diffusion of heavy metals, making it more difficult for them to be absorbed by plant roots. At the same time, the microbial agent can decompose organic matter, release a variety of enzymes and metabolites, and can form insoluble complexes with heavy metals, further promoting the fixation and transformation of heavy metals.

[0023] Furthermore, when the microbial agent includes specific active Pseudomonas paraxanthomonas, Bacillus subtilis and Bacillus amyloliquefaciens, and the bacterial liquid uses three seed liquids with specific inoculation amounts, the heavy metal content in soybean seeds can be reduced.

[0024] Furthermore, the method for preparing the modified biochar comprises the following steps:

[0025] (1) crushing the coconut shell and passing it through a 160-mesh sieve, drying it at 105-110° C. for 15-20 h, and subjecting it to microwave cracking under nitrogen conditions at a cracking temperature of 700-750° C. for 4-5 h to obtain biochar;

[0026] (2) adding 1 part by weight of biochar to 8-10 parts by weight of 60-70 (v / v)% ethanol aqueous solution, adding 0.06-0.1 parts by weight of silane coupling agent KH570, heating at 50-60° C. for 4-6 hours, filtering, washing, and drying to obtain amination biochar;

[0027] (3) Mix the amination biochar, dimethylformamide, cysteine ​​and triethylamine in a weight ratio of 10:(50-55):(1-1.5):(4-6), stir and react at a temperature of 80-85°C for 2-3 hours. After the reaction is completed, filter, wash and dry to obtain modified biochar.

[0028] The present invention attempts to add biochar to organic fertilizer to improve the long-term use effect of bio-organic fertilizer in reducing the heavy metal content in soil, but the effect is not ideal. The present invention can improve soil pH and increase soil biological richness by modifying biochar. Analysis is that by grafting cysteine ​​on biochar, the sulfhydryl group can coordinate with heavy metal ions, and the modified biochar can adsorb and slowly release nutrients in the fertilizer, reduce nutrient loss, and provide a good habitat for microorganisms in the bio-organic fertilizer.

[0029] The present invention provides a method for preparing the biological organic fertilizer for repairing heavy metal contaminated soil, comprising the following steps: weighing various raw materials by weight, adding them into a granulator, spraying water accounting for 20-25% of the total weight of the raw materials, mixing and granulating, and obtaining the biological organic fertilizer for repairing heavy metal contaminated soil.

[0030] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0031] 1. The present invention uses the bark residue after paclitaxel extraction as raw material and ferments it using a specific bacterial solution, which can improve the organic matter content of saline-alkali land.

[0032] 2. The present invention can reduce the content of heavy metal elements in the soil by adding microbial agents.

[0033] 3. The present invention can improve soil pH and increase soil biological richness by modifying biochar.

[0034] 4. When the microbial agent includes specific active Pseudomonas paraxanthomonas, Bacillus subtilis and Bacillus amyloliquefaciens, and the bacterial liquid uses three seed liquids with specific inoculation amounts, the heavy metal content in soybean seeds can be reduced. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0036] The raw materials used in the following examples of the present invention are all commercially available products:

[0037] Slant culture medium was purchased from Shanghai Yuanye Biotechnology Co., Ltd., product number: R22702 slant culture medium (containing agar).

[0038] Beef extract peptone liquid medium was purchased from Beijing Hongrun Baoshun Technology Co., Ltd.

[0039] The fermentation medium comprises the following components: 8 g / L glucose, 7 g / L peptone, 2 g / L ammonium sulfate, 1 g / L magnesium sulfate heptahydrate, 0.5 g / L potassium dihydrogen phosphate, 1 g / L dipotassium hydrogen phosphate, 1.5 g / L sodium chloride and 3 g / L sodium selenite, with a pH of 7.2.

[0040] The residue extracted from the bark of Taxus cuspidata was provided by Shenyang Tianfeng Biopharmaceutical Co., Ltd.

[0041] Halomonas maritima, number: SHBCC D51878, was purchased from Shanghai Collection of Microorganisms.

[0042] Trichoderma harzianum, number: SHBCC D67935, was purchased from Shanghai Collection of Microorganisms Center.

[0043] Aspergillus niger, number SHBCC D22387, was purchased from Shanghai Microbiological Collection Center.

[0044] Pseudomonas paraxanthinus, number: SHBCC D70400, was purchased from Shanghai Microbiological Collection Center.

[0045] Bacillus subtilis, number: SHBCC D71862, was purchased from Shanghai Microbiological Collection Center.

[0046] Bacillus amyloliquefaciens, number: SHBCC D52950, ​​was purchased from Shanghai Microbiological Collection Center.

[0047] Example 1

[0048] This embodiment provides a biological organic fertilizer for remediation of heavy metal contaminated soil, comprising the following raw materials in weight fractions: 18 parts of chicken manure, 26 parts of pig manure, 7 parts of earthworm manure, 12 parts of soybean meal, 22 parts of modified biochar, 18 parts of fermented extract residue, and 8 parts of microbial agent;

[0049] The method for preparing the extraction residue fermentation product comprises the following steps:

[0050] (1) crushing the residue extracted from the bark of Taxus cuspidata into particles with a particle size of 0.2-0.8 cm to obtain a fermentation raw material;

[0051] (2) Spraying bacterial liquid onto the fermentation raw materials, the amount of bacterial liquid used accounting for 0.6% of the weight percentage of the fermentation raw materials, mixing evenly, and then stacking and fermenting at room temperature, turning the pile once every 8 days, fermenting for 5 weeks, and air drying to obtain the extraction residue fermentation product.

[0052] The method for preparing the bacterial solution comprises the following steps:

[0053] (1) The three strains were inoculated on slant culture medium respectively, and static cultured at 32° C. for activation, and three slant culture strains were obtained after the colonies covered the slant; the three strains were: Halomonas marinum, Aspergillus niger, and Trichoderma harzianum;

[0054] (2) The three slant cultured bacteria were inoculated into peptone liquid medium, respectively, and cultured at 37°C and 160 rpm for 23 h to obtain seed liquid of Halomonas marinum, seed liquid of Aspergillus niger, and seed liquid of Trichoderma harzianum, respectively;

[0055] (3) Inoculating the seed liquid of Halomonas marinum, the seed liquid of Aspergillus niger and the seed liquid of Trichoderma harzianum into the same fermentation medium for aerobic fermentation to obtain a bacterial liquid.

[0056] In the step (3), the sea salt mononas seed liquid is inoculated into the fermentation medium at an inoculation rate of 1.6% by weight; the Aspergillus niger seed liquid is inoculated into the fermentation medium at an inoculation rate of 1.5% by weight, and the Trichoderma harzianum seed liquid is inoculated into the fermentation medium at an inoculation rate of 0.7% by weight.

[0057] The microbial agent includes Pseudomonas paraxanthinus, Bacillus subtilis and Bacillus amyloliquefaciens. The bacterial activity of Pseudomonas paraxanthinus in the microbial agent is 10 10 CFU / g; the bacterial activity of Bacillus subtilis in the microbial agent is 10 8 CFU / g; the bacterial activity of Bacillus amyloliquefaciens in the mixed solution is 10 7 CFU / g.

[0058] The preparation method of the modified biochar comprises the following steps:

[0059] (1) Coconut shells were crushed and passed through a 160-mesh sieve, dried at 108° C. for 18 h, and subjected to microwave pyrolysis under nitrogen conditions at a pyrolysis temperature of 720° C. for 4.5 h to obtain biochar;

[0060] (2) adding 1 part by weight of biochar to 9 parts by weight of 65 (v / v)% ethanol aqueous solution, adding 0.08 parts by weight of silane coupling agent KH570, heating at 55° C. for 5 h, filtering, washing, and drying to obtain amination biochar;

[0061] (3) Amination biochar, dimethylformamide, cysteine, and triethylamine in a weight ratio of 10:52:1.2:5 were mixed and stirred for reaction at a temperature of 82°C for 2.5 hours. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified biochar.

[0062] The preparation method of the biological organic fertilizer for repairing heavy metal contaminated soil comprises the following steps: weighing various raw materials by weight, adding them into a granulator, spraying water accounting for 22% of the total weight of the raw materials, mixing and granulating, and obtaining the biological organic fertilizer for repairing heavy metal contaminated soil.

[0063] Example 2

[0064] This embodiment provides a biological organic fertilizer for remediation of heavy metal contaminated soil, comprising the following raw materials in weight fractions: 15 parts of chicken manure, 29 parts of pig manure, 3 parts of earthworm manure, 15 parts of soybean meal, 20 parts of modified biochar, 21 parts of fermented extract residue, and 12 parts of microbial agent;

[0065] The method for preparing the extraction residue fermentation product comprises the following steps:

[0066] (1) crushing the residue extracted from the bark of Taxus cuspidata into particles with a particle size of 0.2-0.8 cm to obtain a fermentation raw material;

[0067] (2) Spraying bacterial liquid onto the fermentation raw materials, the amount of bacterial liquid used accounting for 0.7% of the weight percentage of the fermentation raw materials, mixing evenly, and then stacking and fermenting at room temperature, turning the pile once every 7 days, fermenting for 6 weeks, and air drying to obtain the extraction residue fermentation product.

[0068] The method for preparing the bacterial solution comprises the following steps:

[0069] (1) The three strains were inoculated on slant culture medium respectively, and static cultured at 30° C. for activation, and three slant culture strains were obtained after the colonies covered the slant; the three strains were: Halomonas marinum, Aspergillus niger, and Trichoderma harzianum;

[0070] (2) The three slant cultured bacteria were inoculated into peptone liquid medium, respectively, and cultured at 38° C. and 150 rpm for 25 h to obtain seed solutions of Halomonas marinum, Aspergillus niger, and Trichoderma harzianum, respectively;

[0071] (3) Inoculating the seed liquid of Halomonas marinum, the seed liquid of Aspergillus niger and the seed liquid of Trichoderma harzianum into the same fermentation medium for aerobic fermentation to obtain a bacterial liquid.

[0072] In the step (3), the sea salt mononas seed liquid is inoculated into the fermentation medium at an inoculation rate of 1.4% by weight; the Aspergillus niger seed liquid is inoculated into the fermentation medium at an inoculation rate of 1.6% by weight, and the Trichoderma harzianum seed liquid is inoculated into the fermentation medium at an inoculation rate of 0.6% by weight.

[0073] The microbial agent includes Pseudomonas paraxanthinus, Bacillus subtilis and Bacillus amyloliquefaciens. The bacterial activity of Pseudomonas paraxanthinus in the microbial agent is 10 9 CFU / g; the bacterial activity of Bacillus subtilis in the microbial agent is 10 9 CFU / g; the bacterial activity of Bacillus amyloliquefaciens in the mixed solution is 10 6 CFU / g.

[0074] The preparation method of the modified biochar comprises the following steps:

[0075] (1) Coconut shells were crushed and passed through a 160-mesh sieve, dried at 105° C. for 20 h, and subjected to microwave pyrolysis under nitrogen conditions at a pyrolysis temperature of 700° C. for 5 h to obtain biochar;

[0076] (2) adding 1 part by weight of biochar to 8 parts by weight of 70 (v / v)% ethanol aqueous solution, adding 0.1 parts by weight of silane coupling agent KH570, heating at 50° C. for 6 h, filtering, washing, and drying to obtain amination biochar;

[0077] (3) Amination biochar, dimethylformamide, cysteine, and triethylamine in a weight ratio of 10:55:1:6 were mixed and stirred for reaction at 80°C for 3 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified biochar.

[0078] The preparation method of the biological organic fertilizer for repairing heavy metal contaminated soil comprises the following steps: weighing various raw materials by weight, adding them into a granulator, spraying water accounting for 20% of the total weight of the raw materials, mixing and granulating, and obtaining the biological organic fertilizer for repairing heavy metal contaminated soil.

[0079] Comparative Example 1

[0080] The difference between this comparative example and Example 1 is: a biological organic fertilizer for remediation of heavy metal contaminated soil, comprising the following raw materials in weight fractions: 26 parts of chicken manure, 18 parts of pig manure, 12 parts of earthworm manure, 7 parts of soybean meal, 12 parts of modified biochar, 23 parts of extraction residue fermentation product, and 13 parts of microbial agent.

[0081] Comparative Example 2

[0082] The difference between this comparative example and Example 1 is that seawater salt monospermum is replaced by green Trichoderma (number: SHBCCD13179, purchased from Shanghai Collection of Microorganisms Center), Aspergillus niger is replaced by cinnamon color Aspergillus (number: SHBCC D18581, purchased from Shanghai Collection of Microorganisms Center), and Trichoderma harzianum is replaced by Trichoderma koningii (number: SHBCC D11491, purchased from Shanghai Collection of Microorganisms Center).

[0083] Comparative Example 3

[0084] The difference between this comparative example and Example 1 is that in the step (3), the sea salt mononas seed liquid is inoculated into the fermentation medium at an inoculation amount of 0.7% by weight; the Aspergillus niger seed liquid is inoculated into the fermentation medium at an inoculation amount of 1.0% by weight, and the Trichoderma harzianum seed liquid is inoculated into the fermentation medium at an inoculation amount of 2.2% by weight.

[0085] Comparative Example 4

[0086] The difference between this comparative example and Example 1 is that the microbial agent includes Pseudomonas paraxanthinus, Bacillus subtilis and Bacillus amyloliquefaciens. The bacterial activity of Pseudomonas paraxanthinus in the microbial agent is 10 7 CFU / g; the bacterial activity of Bacillus subtilis in the microbial agent is 1010 CFU / g; the bacterial activity of Bacillus amyloliquefaciens in the mixed solution is 10 8 CFU / g.

[0087] Comparative Example 5

[0088] The difference between this comparative example and Example 1 is that the microbial agent is Pseudomonas paraxanthinus; the bacterial activity of Pseudomonas paraxanthinus in the microbial agent is 2×10 10 CFU / g.

[0089] Comparative Example 6

[0090] The difference between this comparative example and Example 1 is that the biochar is not modified.

[0091] The preparation method of biochar comprises the following steps: crushing coconut shells and passing them through a 160-mesh sieve, drying them at 108° C. for 18 hours, and performing microwave cracking under nitrogen conditions at a cracking temperature of 720° C. for 4.5 hours to obtain biochar.

[0092] Performance Testing

[0093] The bio-organic fertilizers prepared in Examples 1-2 and Comparative Examples 1-6 were subjected to performance tests.

[0094] Test site: Located in a saline-alkali land in Da'an City, Jilin Province, randomly divided into 9 test plots.

[0095] Test crop: Heinong 87 soybean.

[0096] Experimental setting: the experimental group was conventional fertilization + the bio-organic fertilizer of the present invention, the application amount of the bio-organic fertilizer was 40 kg / mu, and the control group was conventional fertilization + 40 kg / mu conventional fertilization;

[0097] Test method: After soybean harvest, collect 0-20cm surface soil and mix thoroughly. Some soil samples are placed in sterile bags, frozen with ice, and then taken back to the laboratory and stored in a -80℃ refrigerator for the determination of soil microbial diversity and community structure. The remaining soil samples are air-dried, ground and sieved for the determination of soil physical and chemical properties.

[0098] Soil pH was measured using a pH meter after extraction with a water-soil ratio of 2.5:1.

[0099] Calculate soybean yield and heavy metal content in soybean kernels.

[0100] The results are shown in Tables 1-2.

[0101] Table 1 Changes in heavy metal content in soil

[0102]

[0103] Table 2 Soybean yield and heavy metal determination in seeds

[0104]

[0105]

[0106] Note: / represents not tested.

[0107] It can be seen from the test data in Table 1-2 that the bio-organic fertilizer of Examples 1-2 of the present invention can improve the effective nutrients and biological activity of the soil, while reducing the element content levels of four heavy metal elements: cadmium, mercury, copper and lead. At the same time, it improves the yield of soybeans and the heavy metal content in soybean grains.

[0108] However, the comparative examples were significantly inferior to the embodiments in the corresponding performance tests because they did not adopt the necessary technical solutions. In comparative example 1, the raw material composition of the bio-organic fertilizer was different, the improvement effect of heavy metals decreased, and the soybean yield decreased; in comparative example 2, the bacterial solution used for the fermentation of the bark residue after the extraction of paclitaxel was different, and it was found that the organic matter content of the saline-alkali land decreased; in comparative example 3, the inoculation amount of the three bacteria in the bacterial solution was different, and it was found that the heavy metal content in soybeans increased; in comparative example 4, the amount of microbial agents was different, and it was found that the heavy metal content in soybeans increased; in comparative example 5, only one kind of microbial agent was used, and it was found that the content level of heavy metal elements in the soil increased; in comparative example 6, the biochar was not modified, and the richness of soil organisms decreased. The above experimental results further prove the importance of the technical solution defined in the present invention for its technical effect.

[0109] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A biological organic fertilizer for remediation of heavy metal contaminated soil, characterized in that: The raw materials include the following weight fractions: 15-20 parts of chicken manure, 24-29 parts of pig manure, 3-9 parts of earthworm manure, 11-15 parts of soybean meal, 20-25 parts of modified biochar, 16-21 parts of extraction residue fermentation product, and 4-12 parts of microbial agent; The method for preparing the extraction residue fermentation product comprises the following steps: (1) crushing the residue extracted from the bark of Taxus cuspidata into particles with a particle size of 0.2-0.8 cm to obtain a fermentation raw material; (2) Spraying bacterial liquid onto the fermentation raw materials, mixing them evenly, and then stacking and fermenting them at room temperature. The piles are turned over every 7-10 days, and the fermentation process is continued for 4-6 weeks. The fermentation process is then air-dried to obtain an extraction residue fermentation product.

2. The bio-organic fertilizer for remediation of heavy metal contaminated soil according to claim 1, characterized in that: The weight percentage of bacterial liquid used in the fermentation raw materials is 0.4-0.7%.

3. The bio-organic fertilizer for remediation of heavy metal contaminated soil according to claim 1, characterized in that: The method for preparing the bacterial solution comprises the following steps: (1) The three strains were inoculated on slant culture medium respectively, and static cultured and activated at 30-35° C., and three slant cultured bacterial strains were obtained after the colonies covered the slant; the three strains were: Halomonas marinum, Aspergillus niger, and Trichoderma harzianum; (2) inoculating the three slant cultured bacteria into peptone liquid culture medium respectively, and culturing at 35-38° C. and 150-170 r / min with shaking for 20-25 h to obtain seed liquid of Halomonas marinum, seed liquid of Aspergillus niger, and seed liquid of Trichoderma harzianum respectively; (3) Inoculating the seed liquid of Halomonas marinum, the seed liquid of Aspergillus niger and the seed liquid of Trichoderma harzianum into the same fermentation medium for aerobic fermentation to obtain a bacterial liquid.

4. The bio-organic fertilizer for remediation of heavy metal contaminated soil according to claim 3, characterized in that: In the step (3), the sea salt mononas seed liquid is inoculated into the fermentation medium at an inoculation amount of 1.4%-1.8% by weight; the Aspergillus niger seed liquid is inoculated into the fermentation medium at an inoculation amount of 1.3%-1.6% by weight, and the Trichoderma harzianum seed liquid is inoculated into the fermentation medium at an inoculation amount of 0.6%-0.9% by weight.

5. The bio-organic fertilizer for remediation of heavy metal contaminated soil according to claim 1, characterized in that: The microbial agents include Pseudomonas paraxanthomonas, Bacillus subtilis and Bacillus amyloliquefaciens.

6. The bio-organic fertilizer for remediation of heavy metal contaminated soil according to claim 5, characterized in that: The bacterial activity of Pseudomonas paraxanthin in the microbial agent is 10 9 CFU / g-10 10 CFU / g; the bacterial activity of Bacillus subtilis in the microbial agent is 10 8 CFU / g-10 9 CFU / g; the bacterial activity of Bacillus amyloliquefaciens in the mixed solution is 10 6 CFU / g-10 7 CFU / g.

7. The bio-organic fertilizer for remediation of heavy metal contaminated soil according to claim 1, characterized in that: The preparation method of the modified biochar comprises the following steps: (1) crushing the coconut shell and passing it through a 160-mesh sieve, drying it at 105-110° C. for 15-20 h, and subjecting it to microwave cracking under nitrogen flow to obtain biochar; (2) adding 1 part by weight of biochar to 8-10 parts by weight of 60-70 (v / v)% ethanol aqueous solution, adding 0.06-0.1 parts by weight of silane coupling agent KH570, heating at 50-60° C. for 4-6 hours, filtering, washing, and drying to obtain amination biochar; (3) The aminated biochar, dimethylformamide, cysteine, and triethylamine are mixed and stirred for reaction at a temperature of 80-85° C. for 2-3 h. After the reaction is completed, the mixture is filtered, washed, and dried to obtain modified biochar.

8. The bio-organic fertilizer for remediation of heavy metal contaminated soil according to claim 7, characterized in that: The microwave pyrolysis conditions are: pyrolysis temperature 700-750°C, pyrolysis time 4-5h.

9. The bio-organic fertilizer for remediation of heavy metal contaminated soil according to claim 7, characterized in that: The weight ratio of amination biochar, dimethylformamide, cysteine ​​and triethylamine is 10:(50-55):(1-1.5):(4-6).

10. A method for preparing a biological organic fertilizer for remediation of heavy metal contaminated soil according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: weighing various raw materials by weight, adding the raw materials into a granulator, spraying water accounting for 20-25% of the total weight of the raw materials, mixing and granulating, and obtaining a biological organic fertilizer for repairing heavy metal polluted soil.

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