Long-acting slow-release charcoal-based microbial organic fertilizer and preparation method thereof

Abstract

The invention relates to the technical field of organic fertilizers, in particular to a long-acting slow-release charcoal-based microbial compound fertilizer and a preparation method thereof. The long-acting slow-release biochar-based microbial organic fertilizer is prepared from the following raw materials in parts by mass: 10 to 20 parts of corn grit, 5 to 10 parts of coated biochar, 1 to 3 parts of monopotassium phosphate, 30 to 40 parts of livestock and poultry manure, 0.001 to 0.01 part of lanthanum ammonium nitrate, 30 to 40 parts of inorganic fertilizer, 0.2 to 0.3 part of microbial agent and 1.5 to 2 parts of epsilon-polylysine, the coated biochar is prepared by the following steps: adding biochar and dopamine hydrochloride into water, mixing, stirring at 30-40 DEG C for 20-30 minutes, adding tris (hydroxymethyl) aminomethane, stirring for 20-30 hours, centrifuging, washing, drying, crushing, feeding into a tubular furnace, keeping the temperature at 300-500 DEG C for 20-40 minutes under the protection of nitrogen, and cooling to room temperature.

Description

Technical Field

[0001] The 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, livestock and poultry manure, etc., 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 average. 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 accelerate, 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, thus affecting the slow-release effect of the fertilizer.

[0004] The activity of traditional biochar-based microbial fertilizers is average, which leads to 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 of 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, the raw materials of which include, by weight: 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 into water, stirring at 30-40°C for 20-30 minutes, adding tris(hydroxymethyl)aminomethane and stirring for 20-30 hours, centrifuging, washing, drying, crushing, 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 tetraethyl orthosilicate is 5-10:1-3.

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

[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 the 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 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 above 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 ε-polylysine has a molecular weight of 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 inoculants 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 by hydrochloric acid, and then ethyl orthosilicate enters the microporous structure of the bamboo charcoal powder and deposits nano silicon dioxide therein, which is then carbonized after coating to form a relatively dense carbon layer on the surface. The present invention not only inherits the characteristics of high specific surface area, but also has strong adsorption capacity and provides stable loading sites for microorganisms, and has excellent fermentation effect. At the same time, the surface hydroxyl group is grafted with the phosphate group of the hydrophilic functional group, which effectively enhances the hydrophilicity and effectively improves the adsorption capacity for water, forms a stable gel-like substance in the soil, and delays 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 lanthanum ammonium nitrate. Not only is the fermentation effect excellent, but also the functional groups (such as hydroxyl and carboxyl) in the network structure are closely related to 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 nutrient release matches the growth needs of plants, reducing nutrient losses and improving nutrient utilization.

[0024] The present invention utilizes the biochar mixture to react with mineral particles in the soil, thereby increasing the aggregate structure and porosity of the soil, helping to improve the aeration and water permeability of the soil, thereby promoting the development of plant roots and nutrient absorption. The biochar mixture obtained by the present invention can also provide a carbon source and energy for soil microorganisms, promote the growth and reproduction of microorganisms, and enhance the activity of microorganisms. The metabolic activities of microorganisms further decompose polysaccharides, release nutrients, increase the effectiveness of nutrients in the soil, and form a virtuous cycle. At the same time, the preparation method is simple, the raw materials are low-cost, and it is suitable for large-scale promotion and 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 The potassium 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.

[0028] Figure 4 This is a comparison chart of the effective live 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 in conjunction with specific embodiments.

[0030] The Bacillus subtilis agent used below was purchased from Jiangsu Greentech Biotechnology Co., Ltd. The accession number of the Bacillus subtilis agent 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, sent to a tubular furnace, kept 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: soak 5g of bamboo charcoal powder in 1mol / L hydrochloric acid, let it stand for 5h, filter, wash once with deionized water, vacuum dry, add 1g of tetraethyl orthosilicate to 30g of 40% ethanol aqueous solution, adjust the pH value of the system to 5-6 with hydrochloric acid, ultrasonically treat for 1h, the ultrasonic frequency is 5kHz, add ammonia water to adjust the pH value of the system to 8-8.6, ultrasonically treat for 1h, the ultrasonic frequency is 5kHz, filter, wash once with water, and vacuum dry.

[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 0.5h, ultrasonically treat for 0.5h, the ultrasonic frequency is 40kHz, and stand in a constant temperature water bath at 60°C for 2h. Use 0.1mol / L sodium hydroxide solution to adjust the pH value of the system to 7-8, and dry to obtain a biochar mixture;

[0039] S2. Mix the biochar mixture, cow dung, lanthanum ammonium nitrate and water, add microbial inoculants and mix evenly, ferment at 28°C for 15 days, add ε-polylysine, inorganic fertilizer and water and stir evenly, use an extrusion molding machine (pore diameter of 2 mm) for extrusion molding, the extrusion molding pressure is 10 MPa, and air dry.

[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 min, 0.1 g of tris(hydroxymethyl)aminomethane was added, stirred for 30 h, centrifuged, washed with deionized water 3 times, dried at 120 °C, crushed, sent to a tubular furnace, kept at 500 °C for 40 min under nitrogen protection, and cooled to room temperature.

[0044] The above-mentioned biochar is prepared by the following steps: soaking 10g of bamboo charcoal powder in 1.5mol / L hydrochloric acid, standing for 10h, filtering, washing 3 times with deionized water, vacuum drying, adding 3g of tetraethyl orthosilicate to 50g of 60% ethanol aqueous solution, adjusting the pH value of the system to 5-6 with hydrochloric acid, ultrasonic treatment for 2h, ultrasonic frequency of 12kHz, adding ammonia water to adjust the pH value of the system to 8-8.6, ultrasonic treatment for 2h, ultrasonic frequency of 12kHz, filtering, washing 3 times with water, 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, ultrasonically treat for 1 hour, the ultrasonic frequency is 60kHz, and stand in a constant temperature water bath at 70°C for 3 hours. Use 0.5 mol / L sodium hydroxide solution to adjust the pH value of the system to 7-8, and dry to obtain a biochar mixture;

[0047] S2. Mix the biochar mixture, chicken manure, lanthanum ammonium nitrate and water, add microbial inoculants 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 of 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 min, 0.07 g of tris(hydroxymethyl)aminomethane was added, stirred for 22 h, centrifuged, washed twice with deionized water, dried at 105 °C, crushed, sent to a tubular furnace, kept at 450 °C for 25 min under nitrogen protection, and cooled to room temperature.

[0052] The above-mentioned biochar is prepared by the following steps: 9g of bamboo charcoal powder is 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 tetraethyl orthosilicate to 45g of 45% ethanol aqueous solution, the pH value of the system is adjusted to 5-6 with hydrochloric acid, ultrasonically treated for 100min, the ultrasonic frequency is 8kHz, ammonia water is added to adjust the pH value of the system to 8-8.6, ultrasonically treated for 100min, the ultrasonic frequency is 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, ultrasonically treat for 50 minutes, the ultrasonic frequency is 45kHz, 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 inoculants 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 (aperture 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 min, 0.03 g of tris(hydroxymethyl)aminomethane was added, stirred for 28 h, centrifuged, washed twice with deionized water, dried at 115 °C, crushed, sent to a tubular furnace, kept at 350 °C for 35 min under nitrogen protection, and cooled to room temperature.

[0060] The above-mentioned biochar is prepared by the following steps: 7g of bamboo charcoal powder is soaked in 1.3mol / L hydrochloric acid, allowed to stand for 7h, filtered, washed twice with deionized water, vacuum dried, and added with 2.5g of tetraethyl orthosilicate to 35g of 55% ethanol aqueous solution, and the pH value of the system is adjusted to 5-6 with hydrochloric acid, ultrasonically treated for 80min at an ultrasonic frequency of 10kHz, and ammonia water is added to adjust the pH value of the system to 8-8.6, ultrasonically treated for 80min at an ultrasonic frequency of 10kHz, filtered, washed twice with water, and vacuum dried.

[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, ultrasonically treat for 40 minutes, the ultrasonic frequency is 55kHz, and stand in a constant temperature water bath at 62°C for 2.8 hours. Use 0.2 mol / L sodium hydroxide solution to adjust the pH value of the system to 7-8, and dry to obtain a biochar mixture;

[0063] S2. Mix the biochar mixture, pig manure, chicken manure, lanthanum ammonium nitrate and water, add microbial inoculants 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 (aperture 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, mixed, 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, sent to a tubular furnace, kept at 400 °C for 30 min under nitrogen protection, and cooled to room temperature.

[0068] The above-mentioned biochar is prepared by the following steps: soaking 8g of bamboo charcoal powder in 1.2mol / L hydrochloric acid, standing for 8h, filtering, washing twice with deionized water, vacuum drying, adding 2g of tetraethyl orthosilicate to 40g of 50% ethanol aqueous solution, adjusting the pH value of the system to 5-6 with hydrochloric acid, ultrasonic treatment for 90min, ultrasonic frequency of 9kHz, adding ammonia water to adjust the pH value of the system to 8-8.6, ultrasonic treatment for 90min, ultrasonic frequency of 9kHz, filtering, washing twice with water, and vacuum drying.

[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, ultrasonically treat for 45 minutes, the ultrasonic frequency is 50kHz, and stand in a constant temperature water bath at 65°C for 2.5 hours. Use 0.3 mol / L sodium hydroxide solution to adjust the pH value of the system to 7-8, and dry to obtain a biochar mixture;

[0071] S2. Mix the biochar mixture, pig manure, chicken manure, lanthanum ammonium nitrate and water, add microbial inoculants 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 (aperture 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 is prepared by the following steps: soaking 8g of bamboo charcoal powder in 1.2mol / L hydrochloric acid, standing for 8h, filtering, washing twice with deionized water, vacuum drying, adding 2g of tetraethyl orthosilicate to 40g of 50% ethanol aqueous solution, adjusting the pH value of the system to 5-6 with hydrochloric acid, ultrasonic treatment for 90min, ultrasonic frequency of 9kHz, adding ammonia water to adjust the pH value of the system to 8-8.6, ultrasonic treatment for 90min, ultrasonic frequency of 9kHz, filtering, washing twice with water, and vacuum drying.

[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, ultrasonically treat for 45 minutes, the ultrasonic frequency is 50kHz, and stand in a constant temperature water bath at 65°C for 2.5 hours. Use 0.3 mol / L sodium hydroxide solution to adjust the pH value of the system to 7-8, and dry to obtain a biochar mixture;

[0078] S2. Mix the biochar mixture, pig manure, chicken manure, lanthanum ammonium nitrate and water, add microbial inoculants 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 (aperture 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, mixed, 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, sent to a tubular furnace, kept at 400 °C for 30 min under nitrogen protection, and cooled to room temperature.

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

[0084] 2 g of tetraethyl 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, ultrasonically treat for 45 minutes, the ultrasonic frequency is 50kHz, and stand in a constant temperature water bath at 65°C for 2.5 hours. Use 0.3 mol / L sodium hydroxide solution to adjust the pH value of the system to 7-8, and dry to obtain a biochar mixture;

[0087] S2. Mix the biochar mixture, pig manure, chicken manure, lanthanum ammonium nitrate and water, add microbial inoculants 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 (aperture 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 fertilizer obtained in Example 5 and Comparative Examples 1-2 was tested as follows:

[0089] 10 g of the organic fertilizer obtained in Example 5 and Comparative Examples 1-2 were weighed, and each group of samples was placed in 1 L of simulated soil solution, which contained electrolytes and pH values ​​similar to those of actual soil. The glass container was placed in a constant temperature shaker, set at 25 ° C, and the shaking speed was 100 rpm. On the 2nd, 8th, and 22nd days, 10 mL of solution was taken out respectively, and 10 mL of simulated soil solution was immediately added after each sampling to keep the solution volume constant.

[0090] The solution was filtered through a 0.45 μm filter membrane to remove undissolved fertilizer particles. The N, P, and K nutrient contents in the solution were determined using an automated chemical analyzer (ICP-OES), and the nutrient concentrations at each time point were 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 test was performed on the long-acting slow-release biochar-based microbial organic fertilizer obtained in Example 5 and Comparative Examples 1-2, 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. Prepare 10 -1 , 10 -2 , 10 -3Bacterial suspensions of different dilutions. Take 0.1mL of 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 for 3 days at 29°C. After the incubation, select plates with colony counts between 30 and 300 to ensure the accuracy of the counts. Calculate the number of effective live 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 live 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 by hydrochloric acid, and then ethyl orthosilicate enters the microporous structure of the bamboo charcoal powder and deposits nano-silicon dioxide therein, which is then carbonized after coating, and then forms a relatively dense carbon layer on the surface, which not only inherits the characteristics of high specific surface area, but also has strong adsorption capacity, and provides stable loading sites for microorganisms, and has excellent fermentation effect. At the same time, the surface hydroxyl groups are grafted with hydrophilic functional group 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 and 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, which not only has excellent fermentation effect, but also the functional groups in the network structure (such as hydroxyl and carboxyl) and nutrient ions such as NH 4+ , K + PO4 3- The formation of a stable complex further controls the release rate of nutrients, and at the same time, the nutrient release matches the plant growth requirements, reducing nutrient losses and improving nutrient utilization. At the same time, the biochar mixture obtained by the present invention can also provide a carbon source and energy for soil microorganisms, promote the growth and reproduction of microorganisms, and enhance the activity of microorganisms.

[0100] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope 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 coated biochar is prepared by the following steps: adding biochar and dopamine hydrochloride into water, stirring at 30-40°C for 20-30 minutes, adding tris(hydroxymethyl)aminomethane and stirring for 20-30 hours, centrifuging, washing, drying, crushing, sending into a tubular furnace, keeping warm at 300-500°C for 20-40 minutes under nitrogen protection, and cooling to room temperature.

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 or 2, characterized in that: 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.

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

5. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 3, characterized in that: The frequency of ultrasonic treatment is 5-12 kHz after the pH value of the system is adjusted to 5-6 by using hydrochloric acid.

6. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 3, 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.

7. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 3, characterized in that: The particle size of bamboo charcoal powder is 10-200μm, and the specific surface area is 320-450m 2 / g.

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

9. The long-acting slow-release biochar-based microbial organic fertilizer according to claim 1, characterized in that: Raw materials for inorganic fertilizers 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.

10. A method for preparing the long-acting slow-release biochar-based microbial organic fertilizer according to any one of claims 1 to 9, 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 10-20MPa and dry.

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