Fertilizer for improving quality of tobacco leaves and preparation method thereof

Abstract

The invention provides a fertilizer for improving tobacco leaf quality and a preparation method thereof, and the preparation method specifically comprises the following steps: 1, mixing organic fertilizer, inorganic fertilizer and diatomite, and granulating; 2, coating the core particles with a mixed solution of a humic acid chelating matrix and a seaweed extract; step 3, carrying out secondary coating and mixing by using a compound bacteria solution; step 4, carrying out third coating by using a chitosan-sodium alginate mixed solution; through multi-layer slow-release coating, organic-inorganic-microorganism cooperation, functional material innovation and process parameter optimization, the defects of an existing tobacco leaf fertilizer in the aspects of nutrient release, soil health, microbial activity and tobacco leaf specificity requirements are comprehensively overcome. The method has the core advantages that the tobacco growth cycle requirement is accurately matched, the fertilizer utilization rate is increased, meanwhile, the physical characteristics and chemical components of the tobacco are remarkably improved, and a technical guarantee is provided for high-quality tobacco production.

Description

Technical Field

[0001] The present invention relates to the technical field of fertilizer preparation, and particularly relates to a fertilizer for improving the quality of tobacco leaves and a preparation method thereof. Background Art

[0002] As an economic crop, tobacco leaves have special nutrient requirements and need balanced nitrogen, phosphorus, potassium and trace elements such as magnesium, boron, zinc, etc. to ensure their growth and quality, such as leaf thickness, combustibility, and aroma components. Traditional tobacco fertilizers mainly include inorganic chemical fertilizers, organic fertilizers and compound fertilizers. Among them, inorganic fertilizers have strong quick-acting properties but are easy to lose, and are likely to cause soil acidification and salinization. Organic fertilizers can improve soil structure but the nutrient release is slow, and it is difficult to meet the peak demand during the growth period of tobacco leaves. Although compound fertilizers combine organic and inorganic components, they often have insufficient synergistic effects due to unreasonable formulations or technological defects.

[0003] In addition, the existing fertilizers also have the following technical problems: 1) Most of them are designed for single quick-acting or slow-release, and cannot match the dynamic requirements of tobacco leaves for "requiring nitrogen in the early stage, phosphorus and potassium in the middle stage, and controlling nitrogen in the later stage", resulting in problems such as too thick or thin leaves and insufficient aroma. 2) Lack of functional bacterial agents, it is difficult to maintain the beneficial microbial population in the soil, and long-term application leads to soil compaction and frequent diseases. 3) The coating materials (such as polyethylene) are difficult to degrade and are easily washed away by rainwater, resulting in nutrient loss. 4) Organic matter and inorganic salts are not chelated or physically combined, resulting in asynchronous nutrient release and poor synergistic effect. 5) The multi-layer coating technology requires multiple high-temperature treatments, with high energy consumption, and the core particles are easily broken, resulting in a low finished product rate.

[0004] Therefore, it has become an urgent problem to provide a tobacco fertilizer that combines quick-acting and slow-acting properties, is not easy to lose nutrients, has good synergistic effects and low costs. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a fertilizer for improving the quality of tobacco leaves and a preparation method thereof, which specifically includes the following steps:

[0006] Step 1: Ferment the organic fertilizer and then mix it with the inorganic fertilizer and diatomite in a double-shaft mixer at a mixing speed of 25-30 rpm for 15-20 minutes at a temperature ≤ 40°C, and then put it into a roller compactor for granulation. The roller compaction pressure is 8-10 Mpa, the die hole diameter is 2.5-3.0 mm, and the moisture content of the particles is 10-13%, to obtain core particles.

[0007] Step 2: First, preheat the core particles to 40 - 50°C and feed them into the fluidized bed. Coat the core particles with a mixed solution of humic acid chelating matrix and seaweed extract. The fluidization gas velocity is 1.2 - 1.5 m / s, the atomization pressure is 0.30 - 0.35 MPa, the spraying rate is 200 - 220 g / min·m2, the temperature is 40 - 50°C, and the adhesion amount is 1.2 - 1.5 g / 100 g of particles to obtain a layer of coated particles.

[0008] Step 3: Load the layer of coated particles into a vacuum adsorption tank, evacuate to -0.08 MPa and maintain for 10 minutes, inject the bacterial solution, maintain the vacuum degree of -0.05 MPa for 20 minutes, and the adsorption temperature is 24 - 26°C. After completion, dry at 30 - 35°C until the surface water content is 4% - 6% to obtain a second layer of coated particles.

[0009] Step 4: Spray the surface of the second layer of coated particles with a chitosan - sodium alginate mixed solution, with a spraying thickness of 50 - 60 μm to obtain a third layer of coated particles. Dry with hot air at 50 - 60°C for 5 - 10 minutes, and then cure at room temperature for 24 hours to obtain the fertilizer.

[0010] Preferably, the mass ratio of the organic fertilizer, inorganic fertilizer, and diatomite in Step 1 is 5:3:1. The organic fertilizer includes livestock manure, straw, distiller's grains, soybean meal, and rapeseed cake with a mass ratio of 5:3:1:2:1. The inorganic fertilizer includes potassium dihydrogen phosphate and urea with a mass ratio of 3:5.

[0011] Preferably, the fermentation operation of the organic fertilizer in Step 1 is to dry the organic fertilizer at 70 - 80°C to constant weight, add the bacterial agent and molasses, add water to a water content of 50 - 60%, the temperature is 50 - 60°C, ferment for 15 - 20 days, the oxygen concentration is 18 - 20%, and turn the pile once every 12 hours.

[0012] Most preferably, the mass ratio of the organic fertilizer, bacterial agent, and molasses is 1000:1:3, and the bacterial agent is EM bacterial agent.

[0013] Preferably, the mass ratio of the humic acid chelating matrix and seaweed extract in Step 2 is 9:1.

[0014] Preferably, the preparation method of the humic acid chelating matrix in Step 2 is to crush weathered coal and pass it through a 150 - 200 - mesh sieve, mix it with a 4% - 5% citric acid solution by mass ratio of 1:5, perform microwave treatment at 800 - 1000 W for 5 - 10 min, centrifuge at 4000 - 4500 rpm for 15 - 20 min, and filter. The filtrate is the humic acid chelating matrix.

[0015] Preferably, the preparation method of the seaweed extract in step two is as follows: Fresh seaweed is crushed and mixed with n-hexane at a mass ratio of 1:6, soaked at 40-50 °C for 2-3 h to obtain defatted seaweed. The defatted seaweed is mixed with a Na 2 CO 3 solution at a mass ratio of 1:15, subjected to a water bath at 70-80 °C for 3-4 h, filtered, the filtrate is mixed with 95% ethanol by volume at a volume ratio of 1:3, allowed to stand at 4-5 °C for 12-16 h, centrifuged at 8000-9000 rpm for 10-15 min, and the precipitate is collected. After drying, the seaweed extract is obtained.

[0016] Preferably, the mass ratio of the first-layer coated particles to the complex bacterial solution in step three is 1:6.

[0017] Preferably, the preparation method of the complex bacterial solution in step three is as follows: The complex bacterial agent and maltodextrin are mixed at a mass ratio of 1:1 and diluted with water to 1×10 8 CFU / mL to obtain the complex bacterial solution.

[0018] Most preferably, the complex bacterial agent includes a Bacillus subtilis bacterial agent and a Trichoderma viride bacterial agent, and the mass ratio is 3:1.

[0019] Preferably, the preparation method of the chitosan-sodium alginate mixed solution in step four is as follows: Chitosan with a deacetylation degree of 92% and sodium alginate are dissolved in an acetic acid solution with a volume fraction of 2-3%, and nano-SiO 2 is added to adjust the viscosity to 110-130 cP.

[0020] Preferably, the mass ratio of chitosan, sodium alginate and the acetic acid solution is 5:2:25.

[0021] The present invention has the following advantages:

[0022] (1) Through the three-layer coating of humic acid-seaweed extract, complex bacterial solution, and chitosan-sodium alginate, the nutrient release rhythm is regulated layer by layer, gradually degraded in the soil, and continuous fertilization during the whole growth period of tobacco leaves is realized.

[0023] (2) The present invention uses EM bacterial agent + molasses fermented organic fertilizer to completely decompose harmful substances and retain active organic matter. The precise ratio of potassium dihydrogen phosphate to urea is 3:5, which meets the high demand of tobacco leaves for phosphorus and potassium, and at the same time avoids excessive nitrogen. The compound of Bacillus subtilis (bacteriostatic) + Trichoderma viride (root-promoting) improves the soil microbial activity and disease resistance.

[0024] (3) Through the chelation of humic acid and citric acid, a stable humic acid complex is formed, enhancing the availability of medium and trace elements. The seaweed extract contains natural auxins (such as indoleacetic acid) and polysaccharides, promoting the cell division of tobacco leaves. Through nano-SiO 2Adjust the viscosity of the chitosan-sodium alginate mixed solution to form a uniform film layer, which has both mechanical strength and slow-release function.

[0025] (4) Add diatomaceous earth to the core particles to provide a biological silicon source, enhance the strength of the tobacco leaf cell wall and disease resistance. At the same time, mannitol and fucoidan in the seaweed extract can promote the synthesis of aroma substances in tobacco leaves. Specific embodiments

[0026] The technical solutions in the embodiments of the invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] The Bacillus subtilis bacterium agent, Trichoderma bacterium agent and EM bacterium agent in the following embodiments are respectively purchased from Shandong Yihao Biotechnology Co., Ltd.

[0028] Example 1

[0029] Step 1: Ferment the organic fertilizer and then put it into a double-shaft mixer together with the inorganic fertilizer and diatomaceous earth for mixing. The mixing speed is 30 rpm, the mixing time is 15 min, and the temperature is 35 °C. Then put it into a roller compactor for granulation. The roller compaction pressure is 8 Mpa, the die hole diameter is 3.0 mm, and the particle water content is 12%, to obtain core particles.

[0030] The fermentation operation of the organic fertilizer is as follows: dry the organic fertilizer at 75 °C until constant weight, add the bacterium agent and molasses, add water to a water content of 60%, the temperature is 55 °C, ferment for 18 days, the oxygen concentration is 20%, and turn the pile once every 12 h. The mass ratio of the organic fertilizer, bacterium agent and molasses is 1000:1:3, and the bacterium agent is an EM bacterium agent.

[0031] The mass ratio of the organic fertilizer, inorganic fertilizer and diatomaceous earth is 5:3:1. The organic fertilizer includes livestock manure, straw, distiller's grains, soybean meal and rapeseed cake with a mass ratio of 5:3:1:2:1. The inorganic fertilizer includes potassium dihydrogen phosphate and urea with a mass ratio of 3:5.

[0032] Step 2: First preheat the core particles to 45 °C and send them into a fluidized bed. Coat the core particles with a mixed solution of humic acid chelating matrix and seaweed extract. The fluidization gas velocity is 1.5 m / s, the atomization pressure is 0.35 MPa, the spraying rate is 200 g / min·m 2 , the temperature is 45 °C, and the attachment amount is: 1.5 g / 100 g of particles, to obtain a layer of coated particles. The mass ratio of the humic acid chelating matrix and seaweed extract is 9:1.

[0033] The preparation method of the humic acid chelating matrix is as follows: crush weathered coal and sieve it through a 200-mesh sieve, mix it with a 5% citric acid solution by a mass ratio of 1:5, treat it with 800W microwave for 10 min, centrifuge it at 4500 rpm for 15 min, and then filter. The filtrate is the humic acid chelating matrix.

[0034] The preparation method of the seaweed extract is as follows: crush fresh seaweed and mix it with n-hexane by a mass ratio of 1:6, soak it at 40 °C for 3 h to obtain defatted seaweed. Mix the defatted seaweed with a 2% Na 2 CO 3 solution by a mass ratio of 1:15, heat it in a water bath at 80 °C for 3 h, filter it, mix the filtrate with 95% ethanol by a volume ratio of 1:3, let it stand at 4 °C for 12 h, centrifuge it at 8000 rpm for 15 min, and then collect the precipitate. After drying, the seaweed extract is obtained.

[0035] Step 3: Load a layer of coated particles into a vacuum adsorption tank, evacuate to -0.08 MPa and maintain for 10 minutes, inject the bacterial solution, maintain the vacuum degree at -0.05 MPa for 20 minutes, and the adsorption temperature is 25 °C. After completion, dry it at 32 °C until the surface moisture content is 4% - 6% to obtain the second-layer coated particles. The mass ratio of the first-layer coated particles to the compound bacterial solution is 1:6.

[0036] The preparation method of the compound bacterial solution is as follows: mix the compound bacterial agent and maltodextrin by a mass ratio of 1:1, and dilute it with water to 1×10 8 CFU / mL to obtain the compound bacterial solution. The compound bacterial agent includes a Bacillus subtilis bacterial agent and a Trichoderma viride bacterial agent, and the mass ratio is 3:1.

[0037] Step 4: Spray the surface of the second-layer coated particles with a chitosan-sodium alginate mixed solution, and the spraying thickness is 60 μm to obtain the third-layer coated particles. Dry them with hot air at 60 °C for 5 minutes, and then cure them at room temperature for 24 hours to obtain the fertilizer.

[0038] The preparation method of the chitosan-sodium alginate mixed solution is as follows: dissolve chitosan with a deacetylation degree of 92% and sodium alginate in a 2% acetic acid solution by volume fraction, and add nano-SiO 2 to adjust the viscosity to 120 cP. The mass ratio of chitosan, sodium alginate and acetic acid solution is 5:2:25.

[0039] Test Example 1

[0040] Select a large field and divide it evenly into several plots. Plant 100 tobacco plants in each plot. The management method refers to "Tobacco Cultivation" published by China Agriculture Press and edited by Fu Yunpeng. Set three treatments. Treatment 1: Completely replace the fertilizer with the fertilizer prepared in Example 1 and keep the amount of fertilizer applied each time unchanged. Treatment 2: Each time of fertilization, half of the mass is the fertilizer described in "Tobacco Cultivation", and the other half is the fertilizer prepared in Example 1. Treatment 3: Fertilize completely according to the guidance in "Tobacco Cultivation". The rest of the field management methods are the same, and the plant height, leaf thickness, leaf size, leaf yield and nicotine content are counted. The results are shown in Table 1.

[0041] Table 1

[0042] Treatment 1 Treatment 2 Treatment 3 Plant height (cm) 155.5 123.8 107.2 Leaf thickness of tobacco (mm) 0.40 0.32 0.27 <![CDATA[Tobacco leaf size (cm 2 )]]> 480 415 384 <![CDATA[Tobacco leaf yield (kg / hm 2 )]]> 3152 2867 2491 Nicotine content (%) 2.6 2.9 3.2

[0043] As can be seen from Table 1, the plant height of Treatment 1 is significantly higher than that of other groups, indicating that the fertilizer of the present invention can promote the growth of tobacco plants. The tobacco leaves of Treatment 1 are thicker and larger, indicating that the fertilizer of the present invention can promote the growth of tobacco leaves and improve the quality of tobacco leaves. The yield of Treatment 1 is significantly higher than that of other groups, indicating that the fertilizer of the present invention has an advantage in fertilizer supply compared with traditional fertilizers. The nicotine content of Treatment 1 is significantly lower than that of other groups, indicating that the fertilizer of the present invention optimizes the nitrogen release rhythm and avoids excessive nitrogen accumulation in the later stage.

[0044] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a fertilizer for improving tobacco leaf quality, characterized in that: The following steps are involved: Step 1, fermenting the organic fertilizer, mixing it with the inorganic fertilizer and diatomaceous earth to obtain core particles with a particle size of 2.0-3.0 mm and a particle moisture content of 10-13%; Step 2: coating the core particles with a mixture of humic acid chelating matrix and seaweed extract, with a coating amount of 1.2-1.5 g / 100 g particles to obtain a layer of coated particles; Step 3, mixing the first layer of coated particles with the composite bacterial solution, vacuum adsorbing for 20-30 minutes, and then drying to a surface moisture content of 4%-6%, to obtain a second layer of coated particles; Step 4: Spray the surface of the two-layer coated particles with a chitosan-sodium alginate mixture with a spraying thickness of 50-60 μm to obtain three-layer coated particles, which are dried and solidified to obtain fertilizer.

2. The method for preparing a fertilizer for improving tobacco leaf quality according to claim 1, characterized in that: The mass ratio of the humic acid chelating matrix to the seaweed extract in step 2 is 9:

1.

3. The method for preparing a fertilizer for improving tobacco leaf quality according to claim 1, characterized in that: The preparation method of the humic acid chelating matrix in step 2 is as follows: the weathered coal is crushed and passed through a 150-200 mesh sieve, mixed with a 4%-5% citric acid solution at a mass ratio of 1:5, subjected to a microwave treatment at 800-1000W for 5-10min, centrifuged at 4000-4500rpm for 15-20min, filtered, and the filtrate is the humic acid chelating matrix.

4. The method for preparing a fertilizer for improving tobacco leaf quality according to claim 1, characterized in that: The preparation method of the seaweed extract in step 2 is as follows: fresh seaweed is crushed and mixed with n-hexane in a mass ratio of 1:6, soaked at 40-50°C for 2-3h to obtain defatted seaweed, the defatted seaweed is mixed with a 2%-2.5% Na2CO3 solution in a mass ratio of 1:15, bathed in a 70-80°C water bath for 3-4h, filtered, the filtrate is mixed with 95% ethanol in a volume ratio of 1:3, allowed to stand at 4-5°C for 12-16h, the precipitate is collected after centrifugation at 8000-9000rpm for 10-15min, and the seaweed extract is obtained after drying.

5. The method for preparing a fertilizer for improving tobacco leaf quality according to claim 1, characterized in that: The mass ratio of the layer of coated particles to the composite bacterial solution in step 3 is 1:

6.

6. The method for preparing a fertilizer for improving tobacco leaf quality according to claim 1, characterized in that: The preparation method of the composite bacterial solution in step 3 is to mix the composite bacterial agent and maltodextrin in a mass ratio of 1:1, and dilute with water to 1×10 8 CFU / mL, and the composite bacterial solution was obtained.

7. The method for preparing a fertilizer for improving tobacco leaf quality according to claim 6, characterized in that: The composite microbial agent comprises a Bacillus subtilis agent and a Trichoderma agent, with a mass ratio of 3:

1.

8. The method for preparing a fertilizer for improving tobacco leaf quality according to claim 1, characterized in that: The preparation method of the chitosan-sodium alginate mixed solution in step 4 is to dissolve chitosan with a deacetylation degree of 92% and sodium alginate in an acetic acid solution with a volume fraction of 2-3%, and add nano-SiO2 to adjust the viscosity to 120±10 cP.

9. The method for preparing a fertilizer for improving tobacco leaf quality according to claim 8, characterized in that: The mass ratio of the chitosan, sodium alginate and acetic acid solution is 5:2:

25.

10. A fertilizer prepared by the method according to any one of claims 1 to 9.