A long-acting slow-release biochar-based microbial organic fertilizer and its preparation method

Abstract

The present invention relates to the technical field of organic fertilizers, and in particular to a long-acting slow-release biochar-based microbial compound fertilizer and a preparation method thereof. The raw materials of the above-mentioned long-acting slow-release biochar-based microbial organic fertilizer include, by mass, 10-20 parts of corn residue, 5-10 parts of coated biochar, 1-3 parts of potassium dihydrogen phosphate, 30-40 parts of livestock and poultry manure, 0.001-0.01 parts of lanthanum ammonium nitrate, 30-40 parts of inorganic fertilizers, 0.2-0.3 parts of microbial agent, and 1.5-2 parts of ε-polylysine; the coated biochar is prepared by the following steps: biochar and dopamine hydrochloride are added to water and mixed, stirred at 30-40°C for 20-30 minutes, tris(hydroxymethyl)aminomethane is added and stirred for 20-30 hours, centrifuged, washed, dried, crushed, sent to a tubular furnace, kept warm at 300-500°C for 20-40 minutes under nitrogen protection, and cooled to room temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of organic fertilizers, and in particular to a long-acting slow-release biochar-based microbial organic fertilizer and a preparation method thereof. Background Art

[0002] Traditional biochar-based fertilizers are mainly derived from agricultural waste, such as straw and livestock and poultry manure, and are prepared through biocharization and fermentation processes. This type of organic fertilizer usually contains a certain amount of organic matter and microorganisms, which can provide nutrients to the soil and promote soil microbial activity.

[0003] However, its bioavailability has always been low. The main reasons are as follows: (1) The slow-release effect is general. This is because the pore structure and organic matter content of biochar are limited, and there is a lack of effective slow-release mechanism. The nutrients in the fertilizer are released rapidly in a short period of time. Especially in high temperature or humid environments, this release may be accelerated, resulting in uneven nutrient release, nutrient loss and environmental impact; (2) The surface functional groups of biochar are not fully combined with the nutrient ions in the fertilizer, resulting in the failure of some nutrients to be effectively adsorbed and fixed, thereby affecting the slow-release effect of the fertilizer.

[0004] The activity of traditional biochar-based microbial fertilizers is average, which leads to a slow decomposition and transformation of organic matter and microorganisms in organic fertilizers in the soil. They are also easily affected by soil environmental factors (such as pH, temperature and humidity), further limiting the bioavailability of fertilizers and nutrient absorption by crops. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a long-acting slow-release biochar-based microbial organic fertilizer and a preparation method thereof.

[0006] A long-acting slow-release biochar-based microbial organic fertilizer comprises the following raw materials in parts by mass: 10-20 parts of corn residue, 5-10 parts of coated biochar, 1-3 parts of potassium dihydrogen phosphate, 30-40 parts of livestock and poultry manure, 0.001-0.01 parts of lanthanum ammonium nitrate, 30-40 parts of inorganic fertilizer, 0.2-0.3 parts of microbial agent, and 1.5-2 parts of ε-polylysine.

[0007] The coated biochar is prepared by the following steps: adding biochar and dopamine hydrochloride to water, stirring at 30-40°C for 20-30 minutes, adding tris(hydroxymethyl)aminomethane and stirring for 20-30 hours, centrifuging, washing, drying, crushing, and sending into a tubular furnace, keeping warm at 300-500°C for 20-40 minutes under nitrogen protection, and cooling to room temperature.

[0008] Preferably, the mass ratio of biochar, dopamine hydrochloride and tris(hydroxymethyl)aminomethane is 5-10:1-4:0.01-0.1.

[0009] Preferably, biochar is prepared by the following steps: soaking bamboo charcoal powder in hydrochloric acid, standing for 5-10 hours, filtering, washing, vacuum drying, adding it to ethanol aqueous solution with ethyl orthosilicate, adjusting the pH value of the system to 5-6, ultrasonic treatment for 1-2 hours, adjusting the pH value of the system to 8-8.6, ultrasonic treatment for 1-2 hours, filtering, washing, and vacuum drying.

[0010] Preferably, the mass ratio of bamboo charcoal powder to ethyl orthosilicate is 5-10:1-3.

[0011] Preferably, the frequency of ultrasonic treatment is 5-12 kHz after the pH value of the system is adjusted to 5-6 with hydrochloric acid.

[0012] Preferably, after adjusting the pH value of the system to 8-8.6 with ammonia water, the frequency of ultrasonic treatment is 5-12 kHz.

[0013] Preferably, the particle size of bamboo charcoal powder is 10-200 μm and the specific surface area is 320-450 m 2 / g.

[0014] Preferably, the microbial agent is Bacillus subtilis, and the viable cell count is 4-9×10 8 cfu / g.

[0015] Preferably, the raw materials of the inorganic fertilizer include urea, monoammonium phosphate, potassium sulfate, magnesium sulfate, zinc sulfate, and borax.

[0016] The mass ratio of the urea, monoammonium phosphate, potassium sulfate, magnesium sulfate, zinc sulfate and borax is 10-15:5-10:1-5:1-2:0.1-1:0.1-1.

[0017] Preferably, the molecular weight of the ε-polylysine is 600-800 Da.

[0018] The method for preparing the above-mentioned long-acting slow-release biochar-based microbial organic fertilizer comprises the following steps:

[0019] S1. Mix corn residue and coated biochar, add potassium dihydrogen phosphate solution, stir, ultrasonicate, stand in a constant temperature water bath, adjust the pH value of the system to 7-8, and dry to obtain a biochar mixture;

[0020] S2. Mix the biochar mixture, livestock and poultry manure, lanthanum ammonium nitrate, and water, add microbial agents and mix evenly, ferment at 28-32°C for 15-20 days, add ε-polylysine, inorganic fertilizer, and water and stir evenly, extrude at 10-20 MPa (the aperture of the extruder is 2-5 mm), and air-dry.

[0021] Beneficial effects:

[0022] The present invention uses bamboo charcoal powder activated with hydrochloric acid, and then ethyl orthosilicate enters the microporous structure of the bamboo charcoal powder and deposits nano-silicon dioxide therein. After coating and carbonization, a relatively dense carbon layer is formed on the surface. The bamboo charcoal powder not only inherits the characteristics of high specific surface area, but also has strong adsorption capacity and provides stable loading sites for microorganisms, resulting in excellent fermentation effect. At the same time, the surface hydroxyl groups are grafted with hydrophilic functional groups such as phosphate groups, which effectively enhances the hydrophilicity and improves the water adsorption capacity, forming a stable gel-like substance in the soil and delaying the release rate of nutrients.

[0023] The present invention utilizes a biochar mixture formed by compounding corn residue with coated biochar, wherein the molecular chains on the biochar mixture are chemically bonded with ε-polylysine to form a three-dimensional network structure, which further enhances the loading of microbial agents and cooperates with the action of lanthanum ammonium nitrate. Not only is the fermentation effect excellent, but the functional groups (such as hydroxyl and carboxyl) in the network structure are closely connected with nutrient ions such as NH 4+ , K + PO4 3- The formation of stable complexes further controls the release rate of nutrients. At the same time, the release of nutrients matches the growth needs of plants, reducing nutrient losses and improving nutrient utilization.

[0024] The present invention utilizes a biochar mixture that interacts with mineral particles in the soil, increasing soil aggregate structure and porosity, helping to improve soil aeration and water permeability, thereby promoting plant root development and nutrient absorption. The resulting biochar mixture also provides a carbon source and energy for soil microorganisms, promoting their growth and reproduction and enhancing their activity. The microbial metabolic activity further decomposes polysaccharides, releasing nutrients, and increasing nutrient availability in the soil, creating a virtuous cycle. Furthermore, the production method is simple, the raw materials are inexpensive, and the mixture is suitable for large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The nitrogen release rate curves of the long-acting slow-release biochar-based microbial organic fertilizers obtained in Example 5 and Comparative Examples 1-2 are shown.

[0026] Figure 2 The phosphorus release rate curves of the long-acting slow-release biochar-based microbial organic fertilizers obtained in Example 5 and Comparative Examples 1-2 are shown.

[0027] Figure 3 This is the potassium release rate curve of the long-acting slow-release biochar-based microbial organic fertilizer obtained in Example 5 and Comparative Examples 1-2.

[0028] Figure 4 This is a comparison chart of the effective viable bacteria count of the long-acting slow-release biochar-based microbial organic fertilizers obtained in Example 5 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0029] The present invention will be further explained below with reference to specific embodiments.

[0030] The Bacillus subtilis agent used below was purchased from Jiangsu Greentech Biotechnology Co., Ltd., the Bacillus subtilis deposit number is CICC 20153, and the concentration of live bacteria in the agent is 8×10 8 cfu / g.

[0031] The bamboo charcoal powder used below was purchased from Lingshou County Zhanxing Mineral Products Co., Ltd., with an average particle size of 50 μm and an average specific surface area of ​​400 m 2 / g)

[0032] Example 1

[0033] A long-acting slow-release biochar-based microbial organic fertilizer, whose raw materials include: 100g corn residue, 50g coated biochar, 10g potassium dihydrogen phosphate, 300g cow dung, 0.01g lanthanum ammonium nitrate, 300g inorganic fertilizer, 2g Bacillus subtilis agent, and 15g ε-polylysine.

[0034] Inorganic fertilizers include: 100g urea, 50g monoammonium phosphate, 10g potassium sulfate, 10g magnesium sulfate, 1g zinc sulfate, and 1g borax.

[0035] The coated biochar was prepared by the following steps: 5 g of biochar and 1 g of dopamine hydrochloride were added to 30 g of water, stirred at 30 °C for 20 min, 0.01 g of tris(hydroxymethyl)aminomethane was added, stirred for 20 h, centrifuged, washed once with deionized water, dried at 100 °C, crushed, and sent to a tubular furnace. It was kept warm at 300 °C for 20 min under nitrogen protection and cooled to room temperature.

[0036] The above-mentioned biochar is prepared by the following steps: soaking 5g of bamboo charcoal powder in 1mol / L hydrochloric acid, letting it stand for 5h, filtering, washing with deionized water once, vacuum drying, adding 1g of ethyl orthosilicate to 30g of 40% ethanol aqueous solution, adjusting the pH value of the system to 5-6 with hydrochloric acid, ultrasonic treatment for 1h, ultrasonic frequency of 5kHz, adding ammonia water to adjust the pH value of the system to 8-8.6, ultrasonic treatment for 1h, ultrasonic frequency of 5kHz, filtering, washing with water once, and vacuum drying.

[0037] The method for preparing the above-mentioned long-acting slow-release biochar-based microbial organic fertilizer comprises the following steps:

[0038] S1. Mix corn residue and coated biochar, add 10% potassium dihydrogen phosphate solution, stir for 0.5 h, ultrasonicate for 0.5 h at a frequency of 40 kHz, and stand in a constant temperature water bath at 60°C for 2 h. Adjust the pH value of the system to 7-8 with 0.1 mol / L sodium hydroxide solution, and dry to obtain a biochar mixture;

[0039] S2. The biochar mixture, cow dung, lanthanum ammonium nitrate, and water were mixed, microbial agents were added and mixed evenly, and fermented at 28°C for 15 days. ε-polylysine, inorganic fertilizer, and water were added and mixed evenly. The mixture was extruded using an extrusion molding machine (aperture size 2 mm) at an extrusion molding pressure of 10 MPa and air-dried.

[0040] Example 2

[0041] A long-acting slow-release biochar-based microbial organic fertilizer, whose raw materials include: 200g corn residue, 100g coated biochar, 30g potassium dihydrogen phosphate, 400g chicken manure, 0.1g lanthanum ammonium nitrate, 400g inorganic fertilizer, 3g Bacillus subtilis agent, and 20g ε-polylysine.

[0042] Inorganic fertilizers include: 150g urea, 100g monoammonium phosphate, 50g potassium sulfate, 20g magnesium sulfate, 10g zinc sulfate, and 10g borax.

[0043] The coated biochar was prepared by the following steps: 10 g of biochar and 4 g of dopamine hydrochloride were added to 60 g of water, mixed, stirred at 40 ° C for 30 minutes, 0.1 g of tris (hydroxymethyl) aminomethane was added, stirred for 30 hours, centrifuged, washed with deionized water 3 times, dried at 120 ° C, crushed, and sent to a tubular furnace. It was kept warm at 500 ° C for 40 minutes under nitrogen protection and cooled to room temperature.

[0044] The above-mentioned biochar was prepared by the following steps: soaking 10g of bamboo charcoal powder in 1.5mol / L hydrochloric acid, letting it stand for 10 hours, filtering, washing with deionized water three times, vacuum drying, adding 3g of ethyl orthosilicate to 50g of 60% ethanol aqueous solution, adjusting the pH value of the system to 5-6 with hydrochloric acid, ultrasonic treatment for 2 hours, ultrasonic frequency of 12kHz, adding ammonia water to adjust the pH value of the system to 8-8.6, ultrasonic treatment for 2 hours, ultrasonic frequency of 12kHz, filtering, washing with water three times, and vacuum drying.

[0045] The method for preparing the above-mentioned long-acting slow-release biochar-based microbial organic fertilizer comprises the following steps:

[0046] S1. Mix corn residue and coated biochar, add 15% potassium dihydrogen phosphate solution, stir for 1 hour, ultrasonicate for 1 hour at a frequency of 60 kHz, and stand in a constant temperature water bath at 70°C for 3 hours. Adjust the pH value of the system to 7-8 with 0.5 mol / L sodium hydroxide solution, and dry to obtain a biochar mixture;

[0047] S2. Mix the biochar mixture, chicken manure, lanthanum ammonium nitrate, and water, add microbial inoculant and mix evenly, ferment at 32°C for 20 days, add ε-polylysine, inorganic fertilizer, and water and stir evenly, use an extrusion molding machine (aperture 5 mm) for extrusion molding, the extrusion molding pressure is 20 MPa, and air-dry.

[0048] Example 3

[0049] A long-acting slow-release biochar-based microbial organic fertilizer, whose raw materials include: 120g corn residue, 90g coated biochar, 15g potassium dihydrogen phosphate, 150g pig manure, 220g chicken manure, 0.02g lanthanum ammonium nitrate, 370g inorganic fertilizer, 2.2g Bacillus subtilis agent, and 19g ε-polylysine.

[0050] Inorganic fertilizers include: 110g urea, 90g monoammonium phosphate, 20g potassium sulfate, 18g magnesium sulfate, 3g zinc sulfate, and 8g borax.

[0051] The coated biochar was prepared by the following steps: 7 g of biochar and 3 g of dopamine hydrochloride were added to 40 g of water, mixed, stirred at 37 ° C for 22 minutes, 0.07 g of tris (hydroxymethyl) aminomethane was added, stirred for 22 hours, centrifuged, washed twice with deionized water, dried at 105 ° C, crushed, and sent to a tubular furnace. It was kept warm at 450 ° C for 25 minutes under nitrogen protection and cooled to room temperature.

[0052] The above-mentioned biochar was prepared by the following steps: 9g of bamboo charcoal powder was soaked in 1.1mol / L hydrochloric acid, allowed to stand for 9h, filtered, washed twice with deionized water, vacuum dried, and added with 1.5g of ethyl orthosilicate to 45g of 45% ethanol aqueous solution, and the pH value of the system was adjusted to 5-6 with hydrochloric acid, ultrasonically treated for 100min at an ultrasonic frequency of 8kHz, and ammonia water was added to adjust the pH value of the system to 8-8.6, ultrasonically treated for 100min at an ultrasonic frequency of 8kHz, filtered, washed twice with water, and vacuum dried.

[0053] The method for preparing the above-mentioned long-acting slow-release biochar-based microbial organic fertilizer comprises the following steps:

[0054] S1. Mix corn residue and coated biochar, add 13% potassium dihydrogen phosphate solution, stir for 40 minutes, ultrasonicate for 50 minutes at a frequency of 45 kHz, and stand in a constant temperature water bath at 68°C for 2.2 hours. Adjust the pH value of the system to 7-8 with 0.4 mol / L sodium hydroxide solution, and dry to obtain a biochar mixture;

[0055] S2. Mix the biochar mixture, pig manure, chicken manure, lanthanum ammonium nitrate, and water, add microbial agents and mix evenly, ferment at 29°C for 19 days, add ε-polylysine, inorganic fertilizer, and water and stir evenly, use an extrusion molding machine (pore diameter of 3 mm) for extrusion molding, the extrusion molding pressure is 12 MPa, and air dry.

[0056] Example 4

[0057] A long-acting slow-release biochar-based microbial organic fertilizer, whose raw materials include: 180g corn residue, 70g coated biochar, 25g potassium dihydrogen phosphate, 100g pig manure, 230g chicken manure, 0.03g lanthanum ammonium nitrate, 330g inorganic fertilizer, 2.8g Bacillus subtilis agent, and 17g ε-polylysine.

[0058] Inorganic fertilizers include: 130g urea, 70g monoammonium phosphate, 40g potassium sulfate, 12g magnesium sulfate, 7g zinc sulfate, and 2g borax.

[0059] The coated biochar was prepared by the following steps: 9 g of biochar and 2 g of dopamine hydrochloride were added to 50 g of water, mixed, stirred at 33 ° C for 28 minutes, 0.03 g of tris (hydroxymethyl) aminomethane was added, stirred for 28 hours, centrifuged, washed twice with deionized water, dried at 115 ° C, crushed, and sent to a tubular furnace. It was kept warm at 350 ° C for 35 minutes under nitrogen protection and cooled to room temperature.

[0060] The above-mentioned biochar was prepared by the following steps: soaking 7g of bamboo charcoal powder in 1.3mol / L hydrochloric acid, letting it stand for 7h, filtering, washing with deionized water twice, vacuum drying, adding 2.5g of ethyl orthosilicate to 35g of 55% ethanol aqueous solution, adjusting the pH value of the system to 5-6 with hydrochloric acid, ultrasonic treatment for 80min, ultrasonic frequency of 10kHz, adding ammonia water to adjust the pH value of the system to 8-8.6, ultrasonic treatment for 80min, ultrasonic frequency of 10kHz, filtering, washing with water twice, and vacuum drying.

[0061] The method for preparing the above-mentioned long-acting slow-release biochar-based microbial organic fertilizer comprises the following steps:

[0062] S1. Mix corn residue and coated biochar, add 11% potassium dihydrogen phosphate solution, stir for 50 minutes, ultrasonicate for 40 minutes at a frequency of 55 kHz, and stand in a constant temperature water bath at 62°C for 2.8 hours. Adjust the pH value of the system to 7-8 with 0.2 mol / L sodium hydroxide solution, and dry to obtain a biochar mixture;

[0063] S2. Mix the biochar mixture, pig manure, chicken manure, lanthanum ammonium nitrate, and water, add microbial agents and mix evenly, ferment at 31°C for 17 days, add ε-polylysine, inorganic fertilizer, and water and stir evenly, use an extrusion molding machine (pore diameter of 3 mm) for extrusion molding, the extrusion molding pressure is 18 MPa, and air dry.

[0064] Example 5

[0065] A long-acting slow-release biochar-based microbial organic fertilizer, whose raw materials include: 150g corn residue, 80g coated biochar, 20g potassium dihydrogen phosphate, 150g pig manure, 200g chicken manure, 0.05g lanthanum ammonium nitrate, 350g inorganic fertilizer, 2.5g Bacillus subtilis agent, and 18g ε-polylysine.

[0066] Inorganic fertilizers include: 120g urea, 80g monoammonium phosphate, 30g potassium sulfate, 15g magnesium sulfate, 5g zinc sulfate, and 5g borax.

[0067] The coated biochar was prepared by the following steps: 8 g of biochar and 2.5 g of dopamine hydrochloride were added to 45 g of water, stirred at 35 °C for 25 min, 0.05 g of tris(hydroxymethyl)aminomethane was added, stirred for 25 h, centrifuged, washed twice with deionized water, dried at 110 °C, crushed, and sent to a tubular furnace. It was kept warm at 400 °C for 30 min under nitrogen protection and cooled to room temperature.

[0068] The above-mentioned biochar was prepared by the following steps: 8g of bamboo charcoal powder was soaked in 1.2mol / L hydrochloric acid, allowed to stand for 8h, filtered, washed twice with deionized water, vacuum dried, added with 2g of ethyl orthosilicate to 40g of 50% ethanol aqueous solution, hydrochloric acid was used to adjust the pH value of the system to 5-6, ultrasonic treatment was performed for 90min, the ultrasonic frequency was 9kHz, ammonia water was added to adjust the pH value of the system to 8-8.6, ultrasonic treatment was performed for 90min, the ultrasonic frequency was 9kHz, filtered, washed twice with water, and vacuum dried.

[0069] The method for preparing the above-mentioned long-acting slow-release biochar-based microbial organic fertilizer comprises the following steps:

[0070] S1. Mix corn residue and coated biochar, add 12% potassium dihydrogen phosphate solution, stir for 45 minutes, ultrasonicate for 45 minutes at a frequency of 50 kHz, and stand in a constant temperature water bath at 65°C for 2.5 hours. Adjust the pH value of the system to 7-8 with 0.3 mol / L sodium hydroxide solution, and dry to obtain a biochar mixture;

[0071] S2. Mix the biochar mixture, pig manure, chicken manure, lanthanum ammonium nitrate, and water, add microbial agents and mix evenly, ferment at 30°C for 18 days, add ε-polylysine, inorganic fertilizer, and water and stir evenly, use an extrusion molding machine (pore diameter of 3 mm) for extrusion molding, the extrusion molding pressure is 15 MPa, and air dry.

[0072] Comparative Example 1

[0073] A long-acting slow-release biochar-based microbial organic fertilizer, whose raw materials include: 150g corn residue, 80g biochar, 20g potassium dihydrogen phosphate, 150g pig manure, 200g chicken manure, 0.05g lanthanum ammonium nitrate, 350g inorganic fertilizer, 2.5g Bacillus subtilis agent, and 18g ε-polylysine.

[0074] Inorganic fertilizers include: 120g urea, 80g monoammonium phosphate, 30g potassium sulfate, 15g magnesium sulfate, 5g zinc sulfate, and 5g borax.

[0075] The above-mentioned biochar was prepared by the following steps: 8g of bamboo charcoal powder was soaked in 1.2mol / L hydrochloric acid, allowed to stand for 8h, filtered, washed twice with deionized water, vacuum dried, added with 2g of ethyl orthosilicate to 40g of 50% ethanol aqueous solution, hydrochloric acid was used to adjust the pH value of the system to 5-6, ultrasonic treatment was performed for 90min, the ultrasonic frequency was 9kHz, ammonia water was added to adjust the pH value of the system to 8-8.6, ultrasonic treatment was performed for 90min, the ultrasonic frequency was 9kHz, filtered, washed twice with water, and vacuum dried.

[0076] The method for preparing the above-mentioned long-acting slow-release biochar-based microbial organic fertilizer comprises the following steps:

[0077] S1. Mix corn residue and biochar, add 12% potassium dihydrogen phosphate solution, stir for 45 minutes, ultrasonicate for 45 minutes at a frequency of 50 kHz, and stand in a constant temperature water bath at 65°C for 2.5 hours. Adjust the pH value of the system to 7-8 with 0.3 mol / L sodium hydroxide solution, and dry to obtain a biochar mixture.

[0078] S2. Mix the biochar mixture, pig manure, chicken manure, lanthanum ammonium nitrate, and water, add microbial agents and mix evenly, ferment at 30°C for 18 days, add ε-polylysine, inorganic fertilizer, and water and stir evenly, use an extrusion molding machine (pore diameter of 3 mm) for extrusion molding, the extrusion molding pressure is 15 MPa, and air dry.

[0079] Comparative Example 2

[0080] A long-acting slow-release biochar-based microbial organic fertilizer, whose raw materials include: 150g corn residue, 80g coated biochar, 20g potassium dihydrogen phosphate, 150g pig manure, 200g chicken manure, 0.05g lanthanum ammonium nitrate, 350g inorganic fertilizer, 2.5g Bacillus subtilis agent, and 18g ε-polylysine.

[0081] Inorganic fertilizers include: 120g urea, 80g monoammonium phosphate, 30g potassium sulfate, 15g magnesium sulfate, 5g zinc sulfate, and 5g borax.

[0082] The coated biochar was prepared by the following steps: 8 g of biochar and 2.5 g of dopamine hydrochloride were added to 45 g of water, stirred at 35 °C for 25 min, 0.05 g of tris(hydroxymethyl)aminomethane was added, stirred for 25 h, centrifuged, washed twice with deionized water, dried at 110 °C, crushed, and sent to a tubular furnace. It was kept warm at 400 °C for 30 min under nitrogen protection and cooled to room temperature.

[0083] The biochar was prepared by the following steps: 8 g of bamboo charcoal powder was soaked in 1.2 mol / L hydrochloric acid, allowed to stand for 8 h, filtered, washed twice with deionized water, and vacuum dried to obtain pretreated bamboo charcoal powder;

[0084] 2 g of ethyl orthosilicate was added to 40 g of 50% ethanol aqueous solution, the pH value of the system was adjusted to 5-6 with hydrochloric acid, ultrasonic treatment was performed for 90 min at an ultrasonic frequency of 9 kHz, ammonia water was added to adjust the pH value of the system to 8-8.6, ultrasonic treatment was performed for 90 min at an ultrasonic frequency of 9 kHz, the solution was filtered, washed twice with water, vacuum dried, and evenly mixed with pretreated bamboo charcoal powder to obtain biochar.

[0085] The method for preparing the above-mentioned long-acting slow-release biochar-based microbial organic fertilizer comprises the following steps:

[0086] S1. Mix corn residue and coated biochar, add 12% potassium dihydrogen phosphate solution, stir for 45 minutes, ultrasonicate for 45 minutes at a frequency of 50 kHz, and stand in a constant temperature water bath at 65°C for 2.5 hours. Adjust the pH value of the system to 7-8 with 0.3 mol / L sodium hydroxide solution, and dry to obtain a biochar mixture;

[0087] S2. Mix the biochar mixture, pig manure, chicken manure, lanthanum ammonium nitrate, and water, add microbial agents and mix evenly, ferment at 30°C for 18 days, add ε-polylysine, inorganic fertilizer, and water and stir evenly, use an extrusion molding machine (pore diameter of 3 mm) for extrusion molding, the extrusion molding pressure is 15 MPa, and air dry.

[0088] The nutrient release rate of the long-acting slow-release biochar-based microbial organic fertilizers obtained in Example 5 and Comparative Examples 1-2 was tested as follows:

[0089] 10g of each organic fertilizer from Example 5 and Comparative Examples 1-2 was weighed and placed into 1L of a simulated soil solution containing electrolytes and a pH similar to those in actual soil. The glass containers were placed in a constant-temperature shaker set at 25°C and 100 rpm. On days 2, 8, and 22, 10mL of each solution was removed. After each sampling, 10mL of the simulated soil solution was immediately added to maintain a constant volume.

[0090] The solution was filtered through a 0.45 μm filter membrane to remove undissolved fertilizer particles. The N, P, and K nutrient content in the solution was determined using an automated chemical analyzer (ICP-OES), and the nutrient concentration at each time point was recorded.

[0091]

[0092] Where ΔC is the change in nutrient concentration (mg / L) and Δt is the time interval (days).

[0093] like Figure 1-Figure 3 As shown, the nutrient release of the organic fertilizer obtained in Example 5 is always lower than that in Comparative Examples 1-2 (P < 0.05).

[0094] The effective viable bacteria count of the long-acting slow-release biochar-based microbial organic fertilizer obtained in Example 5 and Comparative Examples 1-2 was tested as follows:

[0095] Weigh 10g of organic fertilizer and add 100mL of sterile water, let it stand for 20min, and shake it on a rotary shaker at 200r / min for 30min to prepare a mother liquid bacterial suspension. Use a sterile pipette to accurately draw 5mL of the mother liquid bacterial suspension and add it to 45ml of sterile water for 10-fold serial dilution to prepare 10 -1 , 10 -2 , 10 -3Prepare bacterial suspensions at different dilutions. Take 0.1 mL of the bacterial suspension from each dilution and spread it on a nutrient agar plate. Invert the spread medium and place it in a constant temperature incubator at 29°C for 3 days. After incubation, count plates with 30-300 colonies to ensure accuracy. Calculate the number of viable bacteria per gram of sample based on the dilution and colony count.

[0096]

[0097] Where C is the average number of colonies on the plate, D is the dilution factor, and V is the volume applied to the plate.

[0098] like Figure 4 As shown, the number of effective living bacteria in the organic fertilizer obtained in Example 5 is the highest, which is better than that in Comparative Examples 1-2 (P < 0.05).

[0099] The applicant believes that this is because the present invention uses bamboo charcoal powder activated with hydrochloric acid, and ethyl orthosilicate enters the microporous structure of the bamboo charcoal powder and deposits nano-silicon dioxide therein. After coating and carbonization, a relatively dense carbon layer is formed on the surface. It not only inherits the characteristics of high specific surface area, but also has strong adsorption capacity and provides stable loading sites for microorganisms, resulting in excellent fermentation effect. At the same time, the surface hydroxyl groups are grafted with hydrophilic functional groups such as phosphate groups, which effectively enhances hydrophilicity and effectively improves the adsorption capacity for water, forming a stable gel-like substance in the soil and delaying the release rate of nutrients. The biochar mixture formed by compounding corn residue with coated biochar is also used. The molecular chains on it are chemically bonded with ε-polylysine to form a three-dimensional network structure, which further enhances the load on microbial agents and cooperates with the action of lanthanum ammonium nitrate. Not only is the fermentation effect excellent, but the functional groups in the network structure (such as hydroxyl and carboxyl) interact with nutrient ions such as NH 4+ , K + PO4 3- The formation of a stable complex further controls the rate of nutrient release, aligning nutrient release with plant growth requirements, reducing nutrient loss and improving nutrient utilization. Furthermore, the biochar mixture obtained by the present invention can provide a carbon source and energy for soil microorganisms, promoting their growth and reproduction and enhancing their activity.

[0100] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A long-acting slow-release biochar-based microbial organic fertilizer, characterized in that: The raw materials include, by mass: 10-20 parts of corn residue, 5-10 parts of coated biochar, 1-3 parts of potassium dihydrogen phosphate, 30-40 parts of livestock and poultry manure, 0.001-0.01 parts of lanthanum ammonium nitrate, 30-40 parts of inorganic fertilizer, 0.2-0.3 parts of microbial agent, and 1.5-2 parts of ε-polylysine; The raw materials of the inorganic fertilizer include urea, monoammonium phosphate, potassium sulfate, magnesium sulfate, zinc sulfate, and borax; the mass ratio of urea, monoammonium phosphate, potassium sulfate, magnesium sulfate, zinc sulfate, and borax is 10-15:5-10:1-5:1-2:0.1-1:0.1-1; The coated biochar is prepared by the following steps: adding biochar and dopamine hydrochloride to water, stirring at 30-40°C for 20-30 minutes, adding tris(hydroxymethyl)aminomethane and stirring for 20-30 hours, centrifuging, washing, drying, crushing, and placing in a tubular furnace, keeping at 300-500°C for 20-40 minutes under nitrogen protection, and cooling to room temperature; The biochar is prepared by the following steps: soaking bamboo charcoal powder in hydrochloric acid, standing for 5-10 hours, filtering, washing, vacuum drying, adding it with ethyl orthosilicate to an ethanol-water solution, adjusting the pH value of the system to 5-6, ultrasonic treatment for 1-2 hours, adjusting the pH value of the system to 8-8.6, ultrasonic treatment for 1-2 hours, filtering, washing, and vacuum drying; The method for preparing the long-acting slow-release biochar-based microbial organic fertilizer comprises the following steps: S1. Mix corn residue and coated biochar, add potassium dihydrogen phosphate solution, stir, ultrasonicate, stand in a constant temperature water bath, adjust the pH value of the system to 7-8, and dry to obtain a biochar mixture; S2. Mix the biochar mixture, livestock and poultry manure, lanthanum ammonium nitrate and water, add microbial agents and mix evenly, ferment at 28-32°C for 15-20 days, add ε-polylysine, inorganic fertilizer and water and stir evenly, extrude at 10-20 MPa and dry.

2. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 1, characterized in that The mass ratio of biochar, dopamine hydrochloride and tris(hydroxymethyl)aminomethane is 5-10:1-4:0.01-0.

1.

3. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 1, characterized in that The mass ratio of bamboo charcoal powder to ethyl orthosilicate is 5-10:1-3.

4. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 1, characterized in that The pH value of the system is adjusted to 5-6 by using hydrochloric acid, and the frequency of ultrasonic treatment is 5-12 kHz.

5. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 1, characterized in that The pH value of the system is adjusted to 8-8.6 by using ammonia water, and the frequency of ultrasonic treatment is 5-12 kHz.

6. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 1, characterized in that: The particle size of bamboo charcoal powder is 10-200μm, and the specific surface area is 320-450m 2 / g.

7. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 1, characterized in that: The microbial agent is Bacillus subtilis, and its viable bacterial count is 4-9×10 8 cfu / g.

8. A method for preparing the long-acting slow-release biochar-based microbial organic fertilizer according to any one of claims 1 to 7, characterized in that: The steps include: S1. Mix corn residue and coated biochar, add potassium dihydrogen phosphate solution, stir, ultrasonicate, stand in a constant temperature water bath, adjust the pH value of the system to 7-8, and dry to obtain a biochar mixture; S2. Mix the biochar mixture, livestock and poultry manure, lanthanum ammonium nitrate and water, add microbial agents and mix evenly, ferment at 28-32°C for 15-20 days, add ε-polylysine, inorganic fertilizer and water and stir evenly, extrude at 10-20 MPa and dry.

Images