Biochar-based coating agent, microbial fertilizer coated with biochar-based coating agent as well as preparation and application of microbial fertilizer

Abstract

The invention relates to preparation and application of a coating agent, in particular to a biochar-based coating agent, a microbial fertilizer coated with the biochar-based coating agent and preparation and application of the microbial fertilizer. The invention provides the biochar-based coating agent taking the corn straw biochar, the glucosamine, the earthworm protein and the molasses as the main components, and the microbial fertilizer coated by the biochar-based coating agent can effectively reduce the soil bulk density, increase the soil porosity, improve the soil structure, improve the soil water holding capacity and increase the soil pH value; the leaching loss of soluble organic matters in soil is reduced; experiments of the applicant prove that by applying the microbial fertilizer coated with the biochar-based coating agent, the vegetable yield can be increased, the vegetable quality can be improved, the chemical fertilizer consumption can be reduced, continuous cropping obstacles can be relieved, the vegetable yield of greenhouses which are continuously cropped for more than 10 years can be increased, and the application prospect is wide.

Description

Technical Field

[0001] The invention relates to the preparation and application of a coating agent, in particular to a biochar-based coating agent, a microbial fertilizer coated with the biochar-based coating agent, and the preparation and application thereof. Background Art

[0002] Fertilizer is an important agricultural production material. Fertilizer plays an irreplaceable role in promoting the development of food and agricultural production. In recent years, in the process of agricultural production, in order to ensure food security, the amount of agricultural fertilizer in my country has increased significantly. At present, the problems of high fertilizer use and nutrient imbalance in my country are becoming increasingly prominent, which not only causes low fertilizer utilization and reduced agricultural product quality, but also causes problems such as soil ecosystem damage and environmental pollution. Under the threat of global climate change, ensuring food security requires considering the impact on the environment and health at the same time. By rationally utilizing organic nutrient resources and replacing part of chemical fertilizers with organic fertilizers, the combination of organic and inorganic can be achieved. Improving the basic soil fertility of cultivated land and replacing external fertilizer nutrient inputs with internal nutrients in cultivated land not only provides new opportunities for the development of my country's fertilizer industry, but also puts forward new research topics on fertilizer research and production to meet the ever-changing market demand.

[0003] Organic fertilizers are mainly derived from plants and / or animals. They are fermented and decomposed carbon-containing organic materials. Their functions are to improve soil fertility, provide plant nutrition, and improve crop quality. They are processed from biological materials, animal and plant waste, and plant residues, eliminating toxic and harmful substances. They are rich in a large number of beneficial substances, including a variety of organic acids, peptides, and rich nutrients including nitrogen, phosphorus, and potassium. They can not only provide comprehensive nutrition for crops, but also have long fertilizer effects. They can increase and renew soil organic matter, promote microbial reproduction, improve the physical and chemical properties and biological activity of the soil, and are the main nutrients for green food production. Microbial fertilizers refer to a type of fertilizer product that uses the life activities of microorganisms as the core to enable crops to obtain specific fertilizer effects. The existing national standards and industry standards have put forward quantitative requirements for the number of live bacteria in microbial fertilizers, including biological organic fertilizers and compound microbial fertilizers, but effectively ensuring the number of live bacteria in microbial fertilizers has always been a problem in the research and development and production of microbial fertilizers. Therefore, the shelf life of microbial fertilizers is also an important factor in measuring microbial fertilizers. At present, the common practice is to strictly control the humidity and temperature during the production process, add excessive live bacteria and select spore-forming microorganisms to prevent the death of live bacteria to the greatest extent and meet the national and industry standards for the number of live bacteria. The low live bacteria rate is not only an urgent problem to be solved in the research and production of microbial fertilizers, but also seriously restricts the promotion and application of microbial fertilizers.

[0004] Biochar is a carbon-rich product obtained by high-temperature pyrolysis of biomass materials under oxygen-limited conditions. It has the characteristics of developed pore structure, high cation exchange capacity and abundant surface functional groups. At present, biochar-based coated fertilizer technology has not been fully popularized. As far as the applicant knows, there is no relevant coating technology for microbial fertilizers. Summary of the invention

[0005] One of the purposes of the present invention is to provide a biochar-based coating agent.

[0006] The biochar-based coating agent of the present invention is composed of the following raw materials in percentage by weight:

[0007] Corn straw biochar 12.0% to 20.0%; glucosamine 5.0% to 6.5%; earthworm protein 8.0% to 12.0%; molasses 8.0% to 10.0%; the balance is water;

[0008] Corn straw biochar was prepared by the following method:

[0009] The corn straw is heated to 250°C to 800°C under anoxic conditions to produce a black, fluffy, lightweight carbonized product, which is then crushed into corn straw biochar with a particle size of 100 to 150 meshes.

[0010] The main function of corn straw biochar in biochar-based coating agents is to reduce soil bulk density, increase soil porosity, improve soil structure, increase soil water holding capacity, increase soil pH, reduce soil soluble organic matter leaching, and has a good protective effect on strains; the main functions of glucosamine, earthworm protein, and molasses are to provide special nutrients to meet the survival of microorganisms, thereby improving the survival rate of strains; second, glucosamine and molasses have relatively viscous properties, are easy to form films, and are convenient to adhere to the surface of granular microbial fertilizers.

[0011] The second object of the present invention is to provide a method for preparing a biochar-based coating agent, which is to place the raw material components of the biochar-based coating agent in a reactor, dissolve them in water, and stir them for 0.5 to 1.0 hours at a temperature of 45°C to 50°C.

[0012] A third object of the present invention is to provide a microbial fertilizer coated with a biochar-based coating agent.

[0013] A fourth object of the present invention is to provide a method for preparing a microbial fertilizer coated with a biochar-based coating agent, comprising the following process steps:

[0014] A. According to the mass ratio of microbial fertilizer to biochar-based coating agent = 1000: 1.5-2.0, the granular microbial fertilizer is placed in a coating drum, the biochar-based coating agent is atomized and sprayed onto the surface of the microbial fertilizer particles in the coating drum, and the coating drum is rotated so that the biochar-based coating agent is evenly attached to the surface of the granular microbial fertilizer and the microbial fertilizer particles do not stick to each other;

[0015] B. Drying the microbial fertilizer particles attached with a biochar-based coating agent prepared in step A to prepare a microbial fertilizer coated with a biochar-based coating agent, the drying temperature being 30° C. to 40° C. for 8 to 12 minutes.

[0016] A fifth object of the present invention is to provide a microbial fertilizer coated with a biochar-based coating agent for use in fruit or vegetable cultivation.

[0017] Specifically, the fruits and vegetables include fruits and vegetables grown in the open field and in greenhouses.

[0018] Specifically, the greenhouse includes greenhouses that have been continuously cultivated for 10 years or more.

[0019] Specifically, the microbial fertilizer coated with the biochar-based coating agent is used as base fertilizer during the colonization of fruits and vegetables, with a dosage of 50 to 200 kg per mu.

[0020] The substantial features and significant technical advances of the present invention are:

[0021] 1. The present invention uses corn straw biochar as the main component of the biochar-based coating agent, which can effectively reduce soil bulk density, increase soil porosity, improve soil structure, increase soil water holding capacity, increase soil pH, reduce soil soluble organic matter leaching, and has a good protective effect on strains; the main functions of using glucosamine, earthworm protein, and molasses are to provide special nutrients to meet the survival of microorganisms, thereby improving the survival rate of strains; second, glucosamine and molasses have a relatively viscous characteristic, are easy to form a film and are convenient to adhere to the surface of granular microbial fertilizers.

[0022] 2. The microbial fertilizer coated with a biochar-based coating agent provided by the present invention, firstly, effectively fills the gap in the lack of relevant coating technology for domestic microbial fertilizers; secondly, it can effectively prolong the survival time of live bacteria in microbial fertilizers, and solve the problem that the number of live bacteria in existing microbial fertilizers is reduced due to transportation and storage and cannot meet the requirements of national standards and industry standards; thirdly, after the applicant used the microbial fertilizer coated with a biochar-based coating agent in the present invention to apply to a variety of vegetables, it was confirmed that the microbial fertilizer coated with a biochar-based coating agent in the present invention can increase vegetable yield, improve vegetable quality, reduce the amount of chemical fertilizers used, alleviate continuous cropping obstacles, and increase the vegetable yield in greenhouses with continuous cropping for more than 10 years, and has broad application prospects. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with embodiments, but is not intended to be limiting of the present invention. The protection scope of the present invention shall be based on the contents recorded in the claims, and any replacement of equivalent means made based on the description of the present invention shall not depart from the protection scope of the present invention.

[0024] Example 1

[0025] Preparation of microbial fertilizer coated with biochar-based coating agent

[0026] The biochar-based coating agent in this embodiment is composed of the following raw materials in percentage by weight:

[0027] Corn straw biochar 15.0%; glucosamine 5.5%; earthworm protein 9.5%; molasses 10.0%; the balance is water;

[0028] Corn straw biochar was prepared by the following method:

[0029] The corn straw is heated to 250°C to 800°C under anoxic conditions to produce a black, fluffy, lightweight carbonized product, which is then crushed into corn straw biochar with a particle size of 100 to 150 meshes.

[0030] The preparation method of the biochar-based coating agent comprises the following steps: placing each raw material component of the biochar-based coating agent in a reaction kettle, dissolving it in water, and stirring it at a temperature of 45 to 50° C. for 0.5 to 1.0 hour.

[0031] The preparation method of the microbial fertilizer coated with a biochar-based coating agent comprises the following process steps:

[0032] A. According to the mass ratio of microbial fertilizer to biochar-based coating agent = 1000: 1.5-2.0, the granular microbial fertilizer is placed in a coating drum, the biochar-based coating agent is atomized and sprayed onto the surface of the microbial fertilizer particles in the coating drum, and the coating drum is rotated so that the biochar-based coating agent is evenly attached to the surface of the granular microbial fertilizer and the microbial fertilizer particles do not stick to each other;

[0033] B. Drying the microbial fertilizer particles attached with a biochar-based coating agent prepared in step A to prepare a microbial fertilizer coated with a biochar-based coating agent, the drying temperature being 30° C. to 40° C. for 8 to 12 minutes.

[0034] In this embodiment, the granular microbial fertilizer is selected from biological organic fertilizer granules, which are produced by Hebei Runongxin Biotechnology Co., Ltd., and the fertilizer registration number is Microbial Fertilizer (2018) Standard No. (4208).

[0035] Example 2

[0036] Preparation of microbial fertilizer coated with biochar-based coating agent

[0037] The difference between this embodiment and embodiment 1 is that:

[0038] The biochar-based coating agent in this embodiment is composed of the following raw materials in percentage by weight:

[0039] Corn straw biochar 12%; glucosamine 6%; earthworm protein 10%; molasses 9%; the balance is water;

[0040] The granular microbial fertilizer in this embodiment is a composite microbial fertilizer granule produced by Hebei Runongxin Biotechnology Co., Ltd., and the fertilizer registration number is Microbial Fertilizer (2018) Standard No. (2598).

[0041] Example 3

[0042] Preparation of microbial fertilizer coated with biochar-based coating agent

[0043] The difference between this embodiment and embodiment 1 is that:

[0044] The biochar-based coating agent in this embodiment is composed of the following raw materials in percentage by weight:

[0045] Corn straw biochar 20%; glucosamine 5.0%; earthworm protein 8%; molasses 8%; the balance is water;

[0046] The rest of the contents are the same as those in Example 1.

[0047] Example 4

[0048] Preparation of microbial fertilizer coated with biochar-based coating agent

[0049] The difference between this embodiment and embodiment 1 is that:

[0050] The biochar-based coating agent in this embodiment is composed of the following raw materials in percentage by weight:

[0051] Corn straw biochar 12%; glucosamine 5.2%; earthworm protein 12%; molasses 8.5%; the balance is water;

[0052] The rest of the contents are the same as those in Example 1.

[0053] Example 5

[0054] Preparation of microbial fertilizer coated with biochar-based coating agent

[0055] The difference between this embodiment and embodiment 2 is that:

[0056] The biochar-based coating agent in this embodiment is composed of the following raw materials in percentage by weight:

[0057] Corn straw biochar 13%; glucosamine 6.2%; earthworm protein 11%; molasses 9.5%; the balance is water;

[0058] The rest of the contents are the same as those in Example 2.

[0059] Example 6

[0060] Preparation of microbial fertilizer coated with biochar-based coating agent

[0061] The difference between this embodiment and embodiment 2 is that:

[0062] The biochar-based coating agent in this embodiment is composed of the following raw materials in percentage by weight:

[0063] Corn straw biochar 18%; glucosamine 6.5%; earthworm protein 8.5%; molasses 8.2%; the balance is water;

[0064] The rest of the contents are the same as those in Example 2.

[0065] Example 7

[0066] Effect of storage time on the survival rate of microbial strains in microbial fertilizers coated with biochar-based coating agents

[0067] The main strains in the biological organic fertilizer particles used in Example 1 are Bacillus subtilis and Bacillus licheniformis, and the amount added during production is 10 billion cfu / g. The control group is the newly produced biological organic fertilizer directly bagged for commercial packaging, and the test group is the biological organic fertilizer particles coated with biochar-based coating agents newly produced according to the method of Example 1 and bagged for commercial packaging. Compare the viable counts of the two groups 1 day, 15 days, 30 days, and 60 days after production. The survival rate of the strains in the final test group in the four stages is significantly higher than that in the control group, especially in the first 15 days after production, the survival of the bacteria in the test group is most significantly different from that in the control group, and the viable count of the control group shows a rapid downward trend in the early stage, and only 16.67% of the amount of addition is left at 15 days, and then it tends to stabilize, while the viable count of the biological organic fertilizer particles coated with biochar-based coating agents produced by the method of Example 1 The downward trend is slow, and 79.33% of the amount of addition is left at 15 days, and the viable count can also be maintained in the later stage, as shown in Table 1.

[0068] Table 1 Bacterial survival rate (×10 8 cfu / g)

[0069] deal with 1 day 15 days 30 days 60 days Control group 17.67±6.81 16.67±6.11 14.00±4.58 12.67±4.04 Experimental Group 81.00±6.56 79.33±5.13 74.00±5.57 73.67±5.13

[0070] Example 8

[0071] Experiment on the application of microbial fertilizer coated with biochar-based coating agent in the cultivation of cucumber in the open field

[0072] The bio-organic fertilizer granules coated with a biochar-based coating agent prepared in Example 1 were used, and the cucumber variety was Jimei No. 4. A control group and an experimental group were set up in this experiment. The control group applied 150 kg / mu of bio-organic fertilizer granules + 50 kg / mu of bottom-applied compound fertilizer (42%, NPK=22:10:10); the experimental group applied 150 kg / mu of bio-organic fertilizer granules coated with a biochar-based coating agent prepared in Example 1 + 50 kg / mu of bottom-applied compound fertilizer (42%, NPK=22:10:10). On May 5, 2024, the land was prepared and base fertilizer was applied. Colonization was carried out every other day, and watering was carried out once after colonization. The cucumbers were watered once at the end of the seedling squatting. During the fruiting period, water once every 7 to 10 days, and apply 5 kg / mu of urea with water. During the peak fruiting period, water once every 7 to 10 days, and spray a mixture of 20% nitric phosphate fertilizer, 1% potassium dihydrogen phosphate, 0.1% zinc sulfate and 0.25% sodium borate each time. Yellow traps were used to control pests such as aphids and whiteflies, and chlorothalonil dust and smoke were used to control multiple diseases such as gray mold and powdery mildew. The yield per mu of cucumber and the quality of cucumber were finally counted. The experimental group showed better growth than the control group by naked eye observation, with more roots and thick stems and dark green leaves. The final cucumber yield, soluble solids and vitamin C of the experimental group increased by 12.33%, 4.05% and 7.01% (P < 0.05) respectively compared with the control group. The specific results are shown in Table 2.

[0073] Table 2 Application effect of bio-organic fertilizer granules coated with biochar-based coating agent on open-field cucumbers

[0074] deal with Output (kg) Soluble solids (%) Vitamin C (mg / kg) Control group 5663.33±178.63 3.78±0.09 92.96±2.64 Treatment Group 6361.67±120.03 3.94±0.04 99.47±0.84 The treatment group was higher than the control group (%) 12.33 4.05 7.01

[0075] Example 9

[0076] Composite microbial fertilizer granules coated with biochar-based coating agent were used for greenhouse cucumber cultivation for three consecutive years

[0077] The composite microbial fertilizer granules coated with biochar-based coating agents prepared in Example 2 were used. The cucumber variety Jinchun No. 4 and the greenhouse area were 1 mu, which were evenly divided into a control group and a test group. The control group applied 100 kg / mu of composite microbial fertilizer granules + 45 kg / mu of bottom-applied compound fertilizer (42%, NPK=22:10:10); the test group applied 100 kg / mu of composite microbial fertilizer granules coated with biochar-based coating agents prepared in Example 2 + 45 kg / mu of bottom-applied compound fertilizer (42%, NPK=22:10:10). The land was prepared and the base fertilizer was applied at the end of February every year. Colonization was carried out every other day. Cucumbers were topdressed with water at the end of the seedling squatting, and then topdressed with clean water every 1 to 2 times. Topdressing was performed every 7 to 10 days during the peak melon period, and topdressing was performed with water. Each topdressing was 5 kg / mu of urea. Statistics were made on the annual per-mu yield of cucumbers, soil organic matter, soil bulk density and porosity. The average per-acre yield of cucumber and soil organic matter in the final experimental group increased by 11.19% and 0.24% respectively compared with the control group. The soil organic matter in the third year of the experimental group increased by 7.24% compared with the first year. The average soil bulk density of cucumber in the experimental group decreased by 10.43% (P < 0.05). The specific results are shown in Table 3.

[0078] Table 3 Application effect of composite microbial fertilizer granules coated with biochar-based coating agent on greenhouse cucumbers for three consecutive years

[0079]

[0080] Example 10

[0081] Field trial of bio-organic fertilizer granules coated with biochar-based coating agent in cucumber field under continuous cropping obstacle soil

[0082] The bio-organic fertilizer particles coated with the biochar-based coating agent prepared in Example 1 were used to conduct a cucumber field test using the soil of a 20-year continuous cucumber greenhouse, covering an area of ​​4.8 acres. Spring fertilization method: rotary tillage once, broadcast compound fertilizer (42%) 20kg / acre, rotary tillage once again, leveling, ridge formation, 3500 cucumbers per acre. The control group applied bio-organic fertilizer (160kg / acre) in holes, and the test group applied bio-organic fertilizer particles (160kg / acre) coated with the biochar-based coating agent prepared in Example 1 in holes, and selected consistent cucumber seedlings for planting. The total yield of cucumbers in spring and the quality of cucumbers were finally counted. The cucumber yield, soluble solids and vitamin C of the final test group increased by 16.36%, 4.13% and 9.39% (P<0.05) respectively compared with the control group. The specific results are shown in Table 4.

[0083] Table 4 Application effect of bio-organic fertilizer granules coated with biochar-based coating agent on the soil of 20-year continuous cucumber greenhouse

[0084]

[0085] Embodiment 11

[0086] Experiment on the application of microbial fertilizer coated with biochar-based coating agent in the cultivation of open-field tomatoes

[0087] The bio-organic fertilizer granules coated with the biochar-based coating agent prepared in Example 1 were used. Tomato variety: Triumph. A control group and a test group were set up in this experiment. The control group applied 100 kg / mu of bio-organic fertilizer granules + 50 kg / mu of bottom-applied compound fertilizer (42%, NPK=22:10:10); the test group applied 100 kg / mu of bio-organic fertilizer granules coated with the biochar-based coating agent prepared in Example 1 + 50 kg / mu of bottom-applied compound fertilizer (42%, NPK=22:10:10). The land was prepared and the base fertilizer was applied on September 15. Colonization was carried out on September 16. The row spacing was about 60 cm, the plant spacing was about 30 cm, and there were 3500 plants / mu. Watering was carried out once after colonization. During the fruiting period, water was applied once every 8 to 10 days, and 4 kg of urea was applied as fertilizer each time; during the peak fruiting period, 0.2% potassium dihydrogen phosphate or 1.5% superphosphate solution was sprayed every 8 to 10 days, and the tomato yield per mu was calculated. The growth of tomatoes in the experimental group was better than that in the control group, as shown by more roots, thick stems, and dark green leaves. Finally, the tomato yield of the experimental group increased by 17.79% (P < 0.05) compared with the control group. The specific results are shown in Table 5.

[0088] Table 5 Application effect of bio-organic fertilizer granules coated with biochar-based coating agent on open-field tomatoes

[0089] deal with Output (kg) Control group 5066.67±153.69 Experimental Group 5968.00±142.26 The experimental group was higher than the control group (%) 17.79

[0090] Example 12

[0091] Pot experiment of composite microbial fertilizer granules coated with biochar-based coating agent on eggplant in continuous cropping obstacle soil

[0092] The composite microbial fertilizer granules coated with biochar-based coating agents prepared in Example 2 were used to carry out eggplant potted experiments using the soil of a 12-year continuous cucumber greenhouse. The control group used composite microbial fertilizer granules, and the test group used composite microbial fertilizer granules coated with biochar-based coating agents prepared in Example 2. The fertilizer amount was 100g / pot. Select consistent eggplant seedlings, treat 12 pots each, and repeat 4 times. Statistics were performed after 40 days of cultivation in a 25°C light room. The average number of leaves, stem thickness, root dry weight, and plant dry weight of the final test group increased by 25.00% (P < 0.05), 51.90% (P < 0.01), 40.56% (P < 0.01), and 43.83% (P < 0.01) compared with the control group, respectively. The specific results are shown in Table 6. As can be seen from Table 6, the average number of leaves, stem thickness, root dry weight, and plant dry weight of the test group and the control group are significantly different.

[0093] Table 6 Effect of composite microbial fertilizer granules coated with biochar-based coating agent on eggplant potted in 12-year continuous cucumber greenhouse soil test

[0094] deal with Average number of leaves Stem diameter (mm) Root dry weight (g) Plant dry weight (g) Control group 6.67±0.58 5.27±0.21 0.48±0.03 4.32±0.18 Experimental Group 8.33±0.58 8.00±0.20 0.67±0.02 6.21±0.19 improve(%) 25.00 51.90 40.56 43.83

[0095] Example 13

[0096] In the test of improving drought resistance of tomatoes, the composite microbial fertilizer particles coated with a biochar-based coating agent prepared by the method of Example 2 were used as test fertilizers, and the uncoated composite microbial fertilizer particles were used as controls. The tomato pot test was carried out using vegetable field soil as the cultivation matrix. The control group was cultivation matrix + composite microbial fertilizer particles, and the test group was cultivation matrix + composite microbial fertilizer particles coated with a biochar-based coating agent prepared by the method of Example 2 in a ratio of 9:1. Transplant the tomato seedlings that have grown to three compound leaves and are uniform into pots with different treatments and water them thoroughly. 20 pots were treated each time. Cultivate in a solar greenhouse for one month.

[0097] Drought resistance test

[0098] (1) Drought stress method: Take 5 pots for each treatment and subject them to water shortage treatment for more than 5 days. When the leaves wilt and the water content of the top of the plant is less than 20%, water them thoroughly. After 24 hours, observe the recovery of the leaves and test the relative conductivity. Determination method of relative conductivity: Cut the same leaf position of tomatoes from different treatments, rinse them with ultrapure water 5 times, and use clean filter paper to absorb the moisture on the surface of the leaves. Use clean scissors to cut the leaves into uniform and equal weight strips of about 1 cm, put them into graduated test tubes, rinse them with ultrapure water 3 times, and then make up to 20 ml with ultrapure water. Leave them at room temperature for 1 hour. Shake them several times during the period. Shake them well after the time is up, and use a DDS-11A conductivity meter to measure the initial conductivity value C1. Put the test tube in a boiling water bath for 15 minutes, take it out and cool it naturally to room temperature, shake it well and measure the final conductivity value C2. Repeat each treatment three times. Relative conductivity (%) = C1 / C2×100.

[0099] (2) Determination of relative leaf water content: Take leaves from the same part to test the relative leaf water content. The higher the value, the better the leaf water retention performance and the more drought-resistant it is. Detection method: Cut two leaves and quickly put them into an aluminum box of known weight, and weigh the fresh weight Wf; put one of them together with the aluminum box into an oven, kill it at 105℃, then dry it at 80℃ to a constant temperature, and weigh the weight Wd; soak the other in distilled water for 6 to 7 hours, take it out and use filter paper to absorb the surface moisture, and weigh Wt. Relative water content % = (Wf-Wd) / (Wt-Wd) x 100.

[0100] The results are shown in Table 7.

[0101] Table 7 Comparison of drought resistance in different treatments

[0102] deal with Relative conductivity (%) Relative water retention rate (%) Drought leaf recovery rate (%) Control group 27.03±1.31 26.53±1.25 67.83±2.47 Experimental Group 17.77±0.51 34.17±0.91 87.03±2.22

[0103] As can be seen from Table 7, the composite microbial fertilizer particles coated with a biochar-based coating agent prepared by the method of Example 2 can significantly improve the drought resistance of tomato plants.

[0104] Embodiment 14

[0105] Wear resistance of microbial fertilizer particles coated with biochar-based coating agents

[0106] The bio-organic fertilizer particles coated with a biochar-based coating agent prepared in Example 1 and the composite microbial fertilizer particles coated with a biochar-based coating agent prepared in Example 2. The wear resistance of the two fertilizer particles was detected by the residual specific gravity method. Residual specific gravity method: The residual specific gravity is the ratio of the mass of the relatively intact coated fertilizer particles after the wear test to the mass of the coated fertilizer particles weighed before the test. The test steps are: weigh 5 grams of coated fertilizer particles in a 100 ml triangular flask, add 5 steel balls with a particle diameter of 6.0 mm to each bottle, cover it and place it in a constant temperature shaker and oscillate at a speed of 250 rpm, take it out after 30 minutes and pass it through a 2.5 mm sieve, and weigh the mass of the remaining coated fertilizer particles. The results are shown in Table 8. It can be seen that the wear resistance of the two coated fertilizer particles is better, indicating that the coating material has good performance.

[0107] Table 8 Wear resistance of two coated fertilizer particles

[0108] deal with Wear resistance (%) Product prepared in Example 1 99.58±0.05 Product prepared in Example 2 99.95±0.27

Claims

1. Biochar-based coating agent, characterized in that It is composed of the following raw materials in percentage by weight: Corn straw biochar 12.0% to 20.0%; glucosamine 5.0% to 6.5%; earthworm protein 8.0% to 12.0%; molasses 8.0% to 10.0%; the balance is water; Corn straw biochar was prepared by the following method: The corn straw is heated to 250°C to 800°C under anoxic conditions to produce a black, fluffy, lightweight carbonized product, which is then crushed into corn straw biochar with a particle size of 100 to 150 meshes.

2. The method for preparing the biochar-based coating agent according to claim 1, characterized in that The raw material components of the biochar-based coating agent are placed in a reaction kettle and dissolved in water, and then stirred for 0.5 to 1.0 hours at a temperature of 45° C. to 50° C. to prepare the coating agent.

3. A microbial fertilizer coated with the biochar-based coating agent as described in claims 1 and 2.

4. The microbial fertilizer coated with a biochar-based coating agent according to claim 3, characterized in that Microbial fertilizers include granular agricultural microbial agents and / or biological organic fertilizers and / or compound microbial fertilizers.

5. The method for preparing a microbial fertilizer coated with a biochar-based coating agent according to claim 3, characterized in that The process steps include: A. According to the mass ratio of microbial fertilizer to biochar-based coating agent = 1000: 1.5-2.0, the granular microbial fertilizer is placed in a coating drum, the biochar-based coating agent is atomized and sprayed onto the surface of the microbial fertilizer particles in the coating drum, and the coating drum is rotated so that the biochar-based coating agent is evenly attached to the surface of the granular microbial fertilizer and the microbial fertilizer particles do not stick to each other; B. Drying the microbial fertilizer particles attached with a biochar-based coating agent prepared in step A to prepare a microbial fertilizer coated with a biochar-based coating agent, the drying temperature being 30° C. to 40° C. for 8 to 12 minutes.

6. Use of the microbial fertilizer coated with a biochar-based coating agent according to claim 3 in the cultivation of fruits and vegetables.

7. The use according to claim 6, characterized in that The fruits and vegetables include those grown in the open field and in greenhouses.

8. The use according to claim 7, characterized in that The greenhouses described include greenhouses that have been continuously cultivated for 10 years or more.

9. The use according to any one of claims 6, 7 or 8, characterized in that The microbial fertilizer coated with biochar-based coating agent is used as base fertilizer during the colonization of fruits and vegetables, with a dosage of 50 to 200 kg per mu.

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