A full-degradable tobacco seedling hole tray and a preparation method thereof

Abstract

The application discloses a kind of full degradation tobacco seedling hole tray and preparation method thereof, and relates to the technical field of agricultural seedling raising.The application discloses a kind of preparation method of full degradation tobacco seedling hole tray, comprising the following steps: plant fiber is subjected to high-temperature composting, mechanical disc grinding and disassembly, to obtain plant fiber pulp;Plant fiber pulp is blended with synergist, tobacco cellulose nanocrystal and functional additive to prepare slurry;And the slurry is formed by using negative pressure suction filtration forming process, to obtain full degradation tobacco seedling hole tray.The synergist prepared in the application cooperates with tobacco cellulose nanocrystal, provides three functions of strength, water resistance and antibacterial, effectively adjusts the water absorption of the hole tray, maintains the morphological integrity during seedling raising, normal growth and penetration of root system, and greatly improves the success rate of tobacco seedling raising.

Description

Technical Field

[0001] This invention relates to the field of agricultural seedling technology, specifically to a fully degradable tobacco seedling tray and its preparation method. Background Technology

[0002] In the development of vegetable and other economic crops, traditional seedling raising has evolved into plug tray seedling raising, achieving highly efficient seedling production. Plug tray seedling raising is a modern seedling technology system that uses lightweight substrates such as peat moss, vermiculite, and perlite as the seedling substrate, plug trays as seedling containers, and mechanized precision sowing to produce seedlings in one go. It has advantages such as saving labor, reducing costs, high efficiency, and facilitating standardized seedling management. Plug tray seedling raising facilitates long-distance transportation and mechanized transplanting, and it plays a role in protecting the roots of plants during seedling lifting, transportation, and transplanting. After transplanting, seedlings recover quickly, or even eliminate the recovery period, which is conducive to early yield increase and proliferation.

[0003] Currently, the most commonly used seedling containers are plastic seedling trays made of polypropylene and polyvinyl chloride. However, the slow degradation of plastic seedling trays leads to plastic residue pollution in the soil. Straw, as a renewable biomass resource, is rich in biomolecules such as cellulose, hemicellulose, and lignin, and also contains nutrients such as nitrogen, phosphorus, potassium, calcium, and magnesium. Developing biodegradable seedling containers using straw as raw material can not only effectively avoid the environmental pressure of using plastic seedling trays, but also allow the biodegradable containers to serve as organic fertilizer after natural degradation during transplanting, providing nutrients to seedlings and enhancing soil organic matter. Traditional straw seedling containers are mainly prepared using a hot-pressing process with thermosetting adhesives, resulting in high adhesive content and problems such as poor antibacterial properties, insufficient bonding strength, and unbalanced degradation cycles. Summary of the Invention

[0004] The purpose of this invention is to provide a fully degradable tobacco seedling tray and its preparation method, so as to solve the problems of high adhesive content, poor antibacterial properties, insufficient bonding strength, and unbalanced degradation cycle of existing straw seedling containers.

[0005] The objective of this invention is achieved through the following technical solution: A method for preparing a fully degradable tobacco seedling tray includes the following steps: Plant fiber pulp, synergist, tobacco cellulose nanocrystals, functional additives, and water are mixed to prepare a slurry; the slurry is then molded to obtain fully degradable tobacco seedling trays. The preparation method of the synergist includes the following steps: S1: Add calcium-based bentonite, diatomaceous earth, and deionized water to a reaction vessel and mix. Add tobacco lignin, control the temperature at 65-75℃, and react for 2-4 hours under stirring to obtain a modified clay dispersion. Oxidized hydroxypropyl starch, KH550, and deionized water were added to a reaction flask and dispersed. The mixture was activated for 0.5-1 h under stirring at a controlled temperature of 35-40℃. Tobacco pectin was added, and the mixture was kept warm and stirred for 20-40 min. The mixture was then filtered, washed, and dried to obtain reinforced starch gel. S2: Add the enhanced starch glue and deionized water to the reaction vessel and disperse them. Control the temperature at 35-40℃, add sodium lignosulfonate and trehalose, keep warm and stir for 0.5-1h, add the modified clay dispersion and stir, add the antibacterial microcapsule powder and stir, adjust the water content of the system to 30-40%, and obtain the synergist.

[0006] As a further embodiment of the present invention: the addition ratio of calcium-based bentonite, diatomaceous earth, deionized water and tobacco lignin in S1 is 5-6g: 4g: 80-100mL: 1-1.2g; The addition ratio of oxidized hydroxypropyl starch, KH550, deionized water, and tobacco pectin in S1 is 4g:0.1-0.12g:10-20mL:0.12-0.15g.

[0007] As a further aspect of the present invention: the addition ratio of reinforced starch glue, deionized water, sodium lignosulfonate, trehalose, modified clay dispersion, and antibacterial microcapsule powder in S2 is 4g: 10-20mL: 0.3-0.6g: 0.1-0.2g: 100-120g: 4-4.5g.

[0008] As a further aspect of the present invention, the method for preparing antibacterial microcapsule powder includes the following steps: A1: Add β-cyclodextrin, tobacco pectin, and deionized water to a reaction vessel, control the temperature at 45-50℃ and stir for 0.5-1h, control the temperature at 35-40℃, add tobacco stem extract, stir for 3-6h, centrifuge, wash, and dry to obtain inclusion complex; A2: Chitosan and acetic acid solution are added to the reaction vessel for dispersion, inclusion complex is added for dispersion, γ-polyglutamic acid, tea polyphenols, acid salts and deionized water are mixed and added to the reaction vessel, the temperature is controlled at 20-30℃, crosslinking is carried out for 1-3 hours, and then dried to obtain antibacterial microcapsule powder.

[0009] As a further aspect of the present invention: the addition ratio of β-cyclodextrin, tobacco pectin, deionized water and tobacco stalk extract in A1 is 10g: 0.8-1.2g: 50-100mL: 5-8g; In A2, the acetic acid solution is a 1 mol / L aqueous solution of acetic acid; the addition ratio of chitosan, acetic acid solution, inclusion complex, γ-polyglutamic acid, tea polyphenols, and deionized water is 10g: 150-200mL: 16-18g: 0.8-1: 0.25-0.35: 100-120mL.

[0010] As a further aspect of the present invention, the method for preparing tobacco pectin includes the following steps: extracting tobacco straw powder in citric acid solution, filtering, collecting the filtrate, concentrating by rotary evaporation, adding ethanol, allowing it to stand, centrifuging, collecting the precipitate, washing and drying it to obtain tobacco pectin.

[0011] As a further embodiment of the present invention, the preparation method of tobacco lignin includes the following steps: tobacco straw powder is extracted and filtered in sodium hydroxide solution, the pH is adjusted to 2-3, a precipitate is precipitated, the precipitate is collected by centrifugation, washed with water and dried to obtain tobacco lignin.

[0012] As a further embodiment of the present invention, the preparation method of tobacco cellulose nanocrystals includes the following steps: removing lignin from tobacco straw powder with sodium hydroxide solution; removing hemicellulose with acetic acid solution; purifying by acid hydrolysis with sulfuric acid solution, collecting the precipitate; dialyzing the precipitate with water until neutral, ultrasonically nano-sizing, freeze-drying, and vacuum freeze-drying to obtain tobacco cellulose nanocrystals.

[0013] As a further aspect of the present invention, the preparation method of tobacco stalk extract includes the following steps: tobacco stalk waste, ethanol, and deionized water are added to a reaction flask for ultrasonic-assisted extraction, followed by filtration and rotary evaporation for concentration to obtain tobacco stalk extract.

[0014] As a further aspect of the present invention: the mass ratio of plant fiber pulp, synergist, tobacco cellulose nanocrystals, and functional additives is 100:5-25:0.06-0.3:0.5-1.5; As a further aspect of the present invention: the functional additive includes a dispersant and a pH adjuster; the mass ratio of the dispersant to the pH adjuster is 0.5-1:0.2-0.6. As a further aspect of the present invention, the method for preparing plant fiber pulp includes the following steps: composting and fermenting plant straw, disassembling it by mechanical disc milling, and obtaining plant fiber pulp.

[0015] As a further aspect of the present invention, the specific process of composting fermentation is as follows: after the plant straw is crushed, the moisture content is adjusted to 60-70%, and 0.1-1.5% of the total weight of the plant straw is inoculated with a high-temperature fermentation agent for straw to carry out biological fermentation. The process parameters for bio-fermentation are: controlling the composting temperature at 40℃-75℃ and composting for 6-10 days; As a further aspect of the present invention: the plant straw is obtained by mixing one or two of rice straw and sugarcane bagasse in any ratio.

[0016] As a further aspect of the present invention: plant straw is crushed into 5-10cm straw segments.

[0017] As a further aspect of the present invention: during the bio-fermentation process, the oxygen is supplied through timed and quantitative ventilation in a closed environment, and the oxygen content in the pile is adjusted to 10-15%.

[0018] As a further aspect of the present invention: the initial C / N ratio of the plant straw is adjusted to 25-35:1, and the adjustment method is to add a nitrogen source.

[0019] As a further aspect of the present invention: the spacing between the grinding discs in the mechanical disc grinding disassembly is 0.5-3mm.

[0020] As a further aspect of the present invention: the high-temperature fermentation agent for straw includes Bacillus.

[0021] As a further aspect of the present invention, the high-temperature fermentation agent for straw also includes photosynthetic bacteria and yeast.

[0022] As a further aspect of the present invention: the molding process is a negative pressure suction filtration molding process, which includes slurry suction, dehumidification, wet blank transfer, and demolding.

[0023] A fully degradable tobacco seedling tray, prepared by any of the above methods.

[0024] The beneficial effects of this invention are: (1) Imparting long-lasting antibacterial properties to the pelvic plate This invention uses tobacco stem extract as the antibacterial active substance and utilizes the synergistic effect of β-cyclodextrin and tobacco pectin to effectively encapsulate the antibacterial active substance, improving its thermal stability and water solubility. Tobacco pectin can be slowly degraded by pectinase secreted by tobacco roots, achieving precise slow release throughout the seedling cycle. This application also adds γ-polyglutamic acid and tea polyphenols. The numerous carboxyl groups (-COOH) on the γ-polyglutamic acid molecular chain form multiple hydrogen bonds with the amino groups of chitosan and exhibit synergistic cross-linking via ionic bonds. The phenolic hydroxyl groups of tea polyphenols can participate in the construction of the cross-linking network, further enhancing the density of the outer shell and strengthening its structural stability. The carboxyl groups of γ-polyglutamic acid can regulate the surface charge of the microcapsules through protonation / deprotonation; the hydrophobic groups of tea polyphenols can enhance the interfacial affinity between the microcapsules and modified clay, improving dispersion uniformity and prolonging the antibacterial effect.

[0025] (2) To endow the burrowing plate with moisture absorption and wicking properties This invention constructs a composite system of calcium-based bentonite, diatomaceous earth, hydroxypropyl starch, and tobacco lignin. The phenolic hydroxyl groups of tobacco lignin form covalent bonds with the hydroxyl groups on the surface of bentonite, creating a "hydrophobic film" on the surface of the bentonite particles, significantly reducing the water permeation rate. Simultaneously, the porous structure of diatomaceous earth acts as a "water buffer," preventing rapid water permeation or evaporation. The silane segments of KH550 have hydrophobic properties; after crosslinking with starch adhesive, they can block the hydrophilic channels between starch molecules, reducing the water absorption and swelling of the starch adhesive, further enhancing the water resistance of the seedling trays. Trehalose is added to regulate the water release rate, preventing excessive hydrophobicity leading to root dehydration or excessive hygroscopicity leading to tray softening.

[0026] (3) Construct a three-dimensional network to give the pitted disc appropriate compressive strength. This invention incorporates tobacco cellulose nanocrystals, which possess high crystallinity and strength, forming a three-dimensional network structure with starch adhesive and clay. This regulates the degradation cycle difference between starch adhesive and clay, improving the later-stage support of the seedling trays. KH550 forms hydrogen bonds with the hydroxyl groups of starch adhesive and tobacco pectin at one end, and covalent bonds with the hydroxyl groups on the clay surface at the other end, bridging the organic bonding system with the inorganic clay and solving the problem of organic-inorganic interface repulsion. The acidic polysaccharide structure of tobacco pectin can form multiple hydrogen bonds with starch adhesive and straw fibers, enhancing interfacial bonding and improving the overall strength of the seedling trays. This application enhances the compressive strength of the seedling trays through compound components. The application combines negative pressure filtration to tightly interweave straw fibers, utilizing physical and mechanical forces to form structural strength. The seedling trays prepared in this application maintain their morphological integrity even in high-humidity environments with seedling periods of 50-70 days, and disintegrate promptly after transplanting without affecting seedling growth or root penetration by tobacco plants.

[0027] The biodegradable seedling container prepared by this invention is used for tobacco seedling cultivation. It does not affect tobacco seed germination and emergence, resulting in high seedling survival rates and short recovery periods after transplanting. Even under prolonged high humidity, the connection between the seedling holes in the container maintains strong structural strength, making it resistant to loosening under external forces during handling. This facilitates rolling and transport without affecting the field growth of tobacco seedlings. During use, it effectively regulates the water absorption and drainage of the seedling trays, maintaining the integrity of the seedling structure and ensuring normal root growth and penetration. Furthermore, it enables the resource utilization of agricultural waste such as tobacco stalks and sugarcane bagasse, reducing raw material costs and minimizing environmental pollution. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The preparation method of tobacco stalk extract includes the following steps: 100g of tobacco stalk waste, 210mL of ethanol and 90mL of deionized water are added to a reaction flask, and the mixture is extracted with ultrasonic assistance at 70℃ and 40kHz for 1h. After filtration, the mixture is concentrated by rotary evaporation at 60℃ and -0.08MPa to a solid content of 20% to obtain tobacco stalk extract.

[0030] The preparation method of tobacco pectin includes the following steps: 100g of tobacco stalk waste is crushed to 40 mesh, washed and dried to obtain straw powder; 0.5mol / L citric acid solution is added at a material-to-liquid ratio of 1:20, and extracted at 90℃ water bath and 300rpm stirring speed for 2h; the mixture is filtered, the filtrate is collected, and concentrated to 1 / 5 of the original volume by rotary evaporation at 60℃ and -0.08MPa; 3 times the volume of 95% ethanol is added, and the mixture is allowed to stand at 4℃ for 12h; the mixture is centrifuged at 5000r / min for 15min, the precipitate is collected, washed and dried to obtain tobacco pectin.

[0031] The preparation method of tobacco lignin includes the following steps: 100g of tobacco stalk waste is crushed to 40 mesh, washed and dried to obtain straw powder; 5% sodium hydroxide solution is added at a material-to-liquid ratio of 1:15, and extracted at 100℃ and 200rpm for 3h; the mixture is filtered, and 1mol / L hydrochloric acid is added to adjust the pH of the filtrate to 2.0; the precipitate is allowed to stand for 30min to precipitate, and the precipitate is centrifuged at 5000r / min for 15min, collected, washed with water and dried to obtain tobacco lignin.

[0032] The preparation method of tobacco cellulose nanocrystals includes the following steps: 100g of tobacco stalk waste is crushed to 60 mesh, washed, and dried to obtain straw powder; 5% sodium hydroxide solution is added at a material-to-liquid ratio of 1:20, boiled at 80℃ for 1h, washed with water until neutral, 10% acetic acid solution is added, and treated at 100℃ and 200rpm stirring speed for 1h, filtered and washed with water until neutral to obtain crude cellulose; 65% sulfuric acid solution is added at a material-to-liquid ratio of 1:10, hydrolyzed at 50℃ water bath and 400rpm stirring speed for 2h, and centrifuged at 8000r / min for 20min; the precipitate is washed with water and dialyzed to pH 7, sonicated at 40kHz and 300W for 2h to obtain a 50-100nm suspension, frozen at -40℃ for 2h, and dried at -0.1MPa for 24h to obtain tobacco cellulose nanocrystals. Example 1

[0033] The preparation method of antibacterial microcapsule powder includes the following steps: A1: 10g β-cyclodextrin, 0.8g tobacco pectin, and 50mL deionized water were added to a reaction vessel. The reaction was carried out at 45℃ and 600r / min stirring speed for 0.5h. The reaction was then carried out at 35℃, and 5g tobacco stem extract was added. The reaction was carried out at 800r / min stirring speed for 3h. The mixture was then centrifuged, washed, and dried to obtain the inclusion complex. A2: Add 10g of chitosan and 150mL of 1mol / L acetic acid solution to the reaction vessel. At room temperature, keep the mixture at a stirring speed of 500r / min for 30min. Add 16g of inclusion complex for dispersion. Add 0.8g of γ-polyglutamic acid, 0.3g of tea polyphenols and 100mL of deionized water to the reaction vessel. Control the temperature at 20℃ and crosslink for 1h. Spray dry at 120℃ to obtain antibacterial microcapsule powder.

[0034] The preparation method of the synergist includes the following steps: S1: Add 5g of calcium-based bentonite, 4g of diatomaceous earth, and 80mL of deionized water to a reaction vessel and disperse them. Add 1g of tobacco lignin, control the temperature at 65℃, and react for 2h at a stirring speed of 800r / min to obtain a modified clay dispersion. 4g of hydroxypropyl oxidized starch (degree of substitution 0.45), 0.1g of KH550 and 10mL were added to a reaction flask and dispersed. The mixture was activated for 0.5h under the conditions of 35℃ and 200rpm stirring. 0.12g of tobacco pectin was added, and the mixture was kept warm and stirred for 20min. The mixture was then filtered, washed and dried to obtain the enhanced starch gel. S2: Add 4g of reinforced starch glue and 10mL of deionized water to the reaction vessel and disperse. Control the temperature at 35℃, add 0.3g of sodium lignosulfonate and 0.1g of trehalose, keep warm and stir for 0.5h, add 100g of modified clay dispersion, stir at 200rpm for 1.5h, add 4g of antibacterial microcapsule powder, stir at 100rpm for 15min, adjust the water content of the system to 30%, and obtain the synergist. Example 2

[0035] The preparation method of antibacterial microcapsule powder includes the following steps: A1: 10g β-cyclodextrin, 1g tobacco pectin, and 100mL deionized water were added to a reaction vessel. The reaction was carried out at 50℃ and 600r / min stirring speed for 0.5h. The reaction was then carried out at 40℃ with 7g tobacco stem extract. The reaction was carried out at 800r / min stirring speed for 4.5h. The mixture was then centrifuged, washed, and dried to obtain the inclusion complex. A2: Add 10g of chitosan and 200mL of 1mol / L acetic acid solution to the reaction vessel. At room temperature, keep the mixture at a stirring speed of 500r / min for 30min. Add 17g of inclusion complex for dispersion. Add 1g of γ-polyglutamic acid, 0.3g of tea polyphenols and 110mL of deionized water to the reaction vessel. Control the temperature at 25℃ and crosslink for 2h. Spray dry at 120℃ to obtain antibacterial microcapsule powder.

[0036] The preparation method of the synergist includes the following steps: S1: 5.5g of calcium-based bentonite, 4g of diatomaceous earth, and 80mL of deionized water were added to the reaction vessel and dispersed. 1.1g of tobacco lignin was added. The temperature was controlled at 70℃ and the reaction was carried out at a stirring speed of 800r / min for 3h to obtain a modified clay dispersion. 4g of hydroxypropyl oxidized starch (degree of substitution 0.45), 0.11g of KH550 and 15mL were added to a reaction flask and dispersed. The mixture was activated for 1h under the conditions of 35℃ and 200rpm stirring. 0.14g of tobacco pectin was added, and the mixture was kept warm and stirred for 30min. The mixture was then filtered, washed and dried to obtain the enhanced starch gel. S2: Add 4g of reinforced starch glue and 15mL of deionized water to the reaction vessel and disperse. Control the temperature at 40℃, add 0.4g of sodium lignosulfonate and 0.1g of trehalose, keep warm and stir for 0.5h, add 110g of modified clay dispersion, stir at 200rpm for 1.5h, add 4.3g of antibacterial microcapsule powder, stir at 100rpm for 15min, and adjust the water content of the system to 30% to obtain the synergist. Example 3

[0037] The preparation method of antibacterial microcapsule powder includes the following steps: A1: Add 10g β-cyclodextrin, 1.2g tobacco pectin, and 100mL deionized water to a reaction vessel. Maintain the temperature at 50℃ and a stirring speed of 600r / min for 1h. Then, maintain the temperature at 40℃ and add 8g tobacco stem extract. Maintain the temperature at 800r / min for 6h. Centrifuge, wash, and dry to obtain the inclusion complex. A2: Add 10g of chitosan and 200mL of 1mol / L acetic acid solution to the reaction vessel. At room temperature, keep the mixture at a stirring speed of 500r / min for 30min. Add 18g of inclusion complex for dispersion. Add 1g of γ-polyglutamic acid, 0.35g of tea polyphenols and 120mL of deionized water to the reaction vessel. Control the temperature at 30℃ and crosslink for 3h. Spray dry at 120℃ to obtain antibacterial microcapsule powder.

[0038] The preparation method of the synergist includes the following steps: S1: 6g of calcium-based bentonite, 4g of diatomaceous earth, and 100mL of deionized water were added to the reaction vessel and dispersed. 1.2g of tobacco lignin was added. The reaction was carried out at 75℃ and 800r / min for 4h to obtain a modified clay dispersion. 4g of hydroxypropyl oxidized starch (degree of substitution 0.45), 0.12g of KH550 and 20mL were added to a reaction flask and dispersed. The mixture was activated for 1h under the conditions of 40℃ and 200rpm stirring. 0.15g of tobacco pectin was added, and the mixture was kept warm and stirred for 40min. The mixture was then filtered, washed and dried to obtain the enhanced starch gel. S2: Add 4g of reinforced starch glue and 20mL of deionized water to the reaction vessel and disperse. Control the temperature at 40℃, add 0.6g of sodium lignosulfonate and 0.2g of trehalose, keep warm and stir for 0.5-1h, add 120g of modified clay dispersion, stir at 200rpm for 1.5h, add 4.5g of antibacterial microcapsule powder, stir at 100rpm for 15min, and adjust the water content of the system to 30% to obtain the synergist. Example 4

[0039] A method for preparing a fully degradable tobacco seedling tray includes the following steps: Sugarcane bagasse was crushed into 5cm straw segments, nitrogen source was added to adjust the initial C / N ratio to 30:1, moisture was adjusted to 65%, and white rot fungi and Bacillus subtilis compounded at 1.2% of the total weight of plant straw were inoculated for biological fermentation. The oxygen content in the pile was adjusted to 10%, the composting temperature was controlled at 70℃ and composting was carried out for 10 days. The whole grinding discs were mechanically disassembled with a spacing of 1mm to obtain plant fiber pulp. 100 parts by weight of plant fiber pulp, 20 parts by weight of the synergist prepared in Example 1, 0.3 parts by weight of tobacco cellulose nanocrystals, 1 part by weight of dispersant (polyacrylamide), and 0.5 parts by weight of pH adjuster (calcium carbonate) were mixed and water was added to prepare a slurry with a moisture content of 70 wt%. The slurry was treated by a negative pressure suction filtration molding process, including slurry suction, dehumidification, wet blank transfer, and demolding; and a fully degradable tobacco seedling tray was obtained. Example 5

[0040] Compared with Example 4, the only difference is that the synergist prepared in Example 1 was replaced in equal amounts with the synergist prepared in Example 2, while the remaining components and preparation methods are completely the same as in Example 4. Example 6

[0041] Compared with Example 4, the only difference is that the synergist prepared in Example 1 was replaced in equal amounts with the synergist prepared in Example 3, while the remaining components and preparation methods are completely consistent with Example 4.

[0042] Comparative Example 1 The preparation method of antibacterial microcapsule powder includes the following steps: A1: 11g of β-cyclodextrin and 100mL of deionized water were added to the reaction vessel. The reaction was carried out at 50℃ and 600r / min stirring speed for 0.5h. The reaction was carried out at 40℃ and 7g of tobacco stem extract were added. The reaction was carried out at 800r / min stirring speed for 4.5h. The mixture was centrifuged, washed and dried to obtain the inclusion complex. A2: Add 10g of chitosan and 200mL of 1mol / L acetic acid solution to the reaction vessel. At room temperature, keep the mixture at a stirring speed of 500r / min for 30min. Add 17g of inclusion complex for dispersion. Add 1g of γ-polyglutamic acid, 0.3g of tea polyphenols and 110mL of deionized water to the reaction vessel. Control the temperature at 25℃ and crosslink for 2h. Spray dry at 120℃ to obtain antibacterial microcapsule powder.

[0043] Comparative Example 2 The preparation method of antibacterial microcapsule powder includes the following steps: A1: 10g β-cyclodextrin, 1g tobacco pectin, and 100mL deionized water were added to a reaction vessel. The reaction was carried out at 50℃ and 600r / min stirring speed for 0.5h. The reaction was then carried out at 40℃ with 7g tobacco stem extract. The reaction was carried out at 800r / min stirring speed for 4.5h. The mixture was then centrifuged, washed, and dried to obtain the inclusion complex. A2: Add 10g of chitosan and 200mL of 1mol / L acetic acid solution to the reaction vessel. At room temperature, keep the reaction at 500r / min for 30min with stirring. Add 17g of inclusion complex for dispersion, control the temperature at 25℃, crosslink for 2h, and spray dry at 120℃ to obtain antibacterial microcapsule powder.

[0044] Comparative Example 3 The preparation method of the synergist includes the following steps: S1: 6g of calcium-based bentonite, 4g of diatomaceous earth, and 100mL of deionized water were added to the reaction vessel and dispersed. 1.2g of tobacco lignin was added. The reaction was carried out at 75℃ and 800r / min for 4h to obtain a modified clay dispersion. S2: 4g of oxidized hydroxypropyl starch (degree of substitution 0.45) and 20mL of deionized water were added to the reaction vessel and dispersed. The temperature was controlled at 40℃. 0.6g of sodium lignosulfonate and 0.2g of trehalose were added and stirred at this temperature for 0.5-1h. 120g of modified clay dispersion was added and stirred at 200rpm for 1.5h. 4.5g of the antibacterial microcapsule powder prepared in Example 2 was added and stirred at 100rpm for 15min. The water content of the system was adjusted to 30% to obtain the synergist.

[0045] Comparative Example 4 The preparation method of the synergist includes the following steps: S1: Add 6g of calcium-based bentonite, 4g of diatomaceous earth, and 100mL of deionized water to a reaction vessel, control the temperature at 75℃, and react for 4h at a stirring speed of 800r / min to obtain a modified clay dispersion. 4g of hydroxypropyl oxidized starch (degree of substitution 0.45), 0.12g of KH550 and 20mL were added to a reaction flask and dispersed. The mixture was activated for 1h under the conditions of 40℃ and 200rpm stirring. 0.15g of tobacco pectin was added, and the mixture was kept warm and stirred for 40min. The mixture was then filtered, washed and dried to obtain the enhanced starch gel. S2: Add 4g of reinforced starch glue and 20mL of deionized water to the reaction vessel and disperse. Control the temperature at 40℃, add 0.6g of sodium lignosulfonate and 0.2g of trehalose, keep warm and stir for 0.5-1h, add 120g of modified clay dispersion, stir at 200rpm for 1.5h, add 4.5g of antibacterial microcapsule powder prepared in Example 2, stir at 100rpm for 15min, and adjust the water content of the system to 30% to obtain the synergist.

[0046] Comparative Example 5 Compared with Example 4, the only difference is that the antibacterial microcapsule powder prepared in Example 1 was replaced in equal amounts with the antibacterial microcapsule powder prepared in Comparative Example 1. The remaining components and preparation methods are completely consistent with Example 4.

[0047] Comparative Example 6 Compared with Example 4, the only difference is that the antibacterial microcapsule powder prepared in Example 1 was replaced in equal amounts with the antibacterial microcapsule powder prepared in Comparative Example 2. The remaining components and preparation methods are completely the same as in Example 4.

[0048] Comparative Example 7 Compared with Example 4, the only difference is that the synergist prepared in Example 1 was replaced in equal amounts with the synergist prepared in Comparative Example 3, while the remaining components and preparation methods are completely consistent with Example 4.

[0049] Comparative Example 8 Compared with Example 4, the only difference is that the synergist prepared in Example 1 was replaced in equal amounts with the synergist prepared in Comparative Example 4, while the remaining components and preparation methods are completely consistent with Example 4.

[0050] Comparative Example 9 Compared with Example 4, only the tobacco fiber nanocrystals added in Example 4 were removed, while the remaining components and preparation methods were completely the same as in Example 4.

[0051] Performance testing (1) Compressive strength: The compressive strength of the puncture trays was tested according to GB / T 1448-2005; the puncture trays were immersed in deionized water for 24 hours, and the wet compressive strength was tested after they were taken out; the test results are shown in Table 1; (2) Water absorption rate: The seedling trays were immersed in water for 24 hours and the water absorption rate was calculated. The test results are shown in Table 1. (3) Degradation test of the seed tray: The test was carried out according to GB / T 19277.1-2011. The prepared seed tray was buried in the tobacco-specific matrix, and the weight loss rate was calculated after 50 days. The test results are shown in Table 1. Physicochemical properties of the tobacco-specific base: pH 5.66, EC 921 μS / cm, bulk density 0.26 g / cm³. 3 The total porosity is 84.19%. The components of the tobacco-specific base include: 3.93 g / kg total nitrogen, 0.18 g / kg total phosphorus, 73.3 mg / kg ammonium nitrogen, 8 mg / kg nitrate nitrogen, 17.55 mg / kg available phosphorus, 1940 mg / kg available potassium, 46.68% organic matter; 65.38 mg / kg Cr, 25.08 mg / kg Ni, 5.31 mg / kg As, 0.69 mg / kg Cd, 0.15 mg / kg Hg, and 22.19 mg / kg Pb.

[0052] Table 1: Statistical Table of Stability Test Data for Acupuncture Plates in Examples 4-6 and Comparative Examples 5-9 Example 4 1.6 2.5 25.1 95.2 Example 5 1.7 2.7 24.2 98.1 Example 6 1.6 2.6 24.7 97.2 Comparative Example 5 1.1 2.0 33.3 94.3 Comparative Example 6 1.2 2.1 31.0 95.2 Comparative Example 7 1.0 1.8 38.5 93.5 Comparative Example 8 1.3 2.2 30.4 94.5 Comparative Example 9 1.1 2.1 31.2 88.4 As shown in Table 1, the compressive strength of the seed tray prepared in this application reaches more than 2.5 MPa in the dry state and more than 1.5 MPa in the wet state, both of which are higher than those of comparative examples 5-9. Moreover, the seed tray prepared in this application has a low water absorption rate and a high degradation rate after 50 days in tobacco-specific substrate. That is, the seed tray prepared in this application still has strong structural strength at the connection between the seed holes under high moisture conditions even when it is in a high humidity environment for a long time, and it is completely degraded after use without polluting the environment.

[0053] (4) Anti-mildew test ① A 50g wet soil sample obtained from the field soil was mixed with sterile water at a ratio of 1:50 and shaken for 10 minutes. The solution containing soil microorganisms was extracted by filtering with sterile gauze and the dominant pathogenic bacteria were isolated and purified. The seedling trays were ground to obtain a 10% extract, which was mixed with the pathogenic bacteria culture medium. The antibacterial rate of the seedling trays was observed after 30 days. The test results are shown in Table 2. ② Fungal spores that had become moldy were scraped from the outer wall of tobacco seedling containers after 20 days of seedling cultivation. After being filtered with sterile gauze, the spores were aseptically spread on PDA medium and cultured for 10 days to isolate and purify the dominant pathogenic bacteria. The seedling trays were ground to obtain a 10% extract, which was mixed with the pathogenic bacteria culture medium. The antibacterial rate of the seedling trays was observed after 30 days. The test results are shown in Table 2. Table 2: Statistical Table of Stability Test Data for Acupuncture Plates in Examples 4-6 and Comparative Examples 5-9 Example 4 92.2 90.3 Example 5 93.2 90.5 Example 6 93.1 90.2 Comparative Example 5 75.5 68.5 Comparative Example 6 78.7 72.3 Comparative Example 7 80.8 75.4 Comparative Example 8 83.0 79.5 Comparative Example 9 90.4 88.1 As shown in Table 2, the seed trays prepared in this application utilize tobacco stalk extract, γ-polyglutamic acid, and tea polyphenols to form an antibacterial system. This system targets pathogens such as Fusarium in the soil and inhibits saprophytic fungi such as Trichoderma on the outer wall of the container, overcoming the limitation of traditional antibacterial agents having a narrow antibacterial spectrum. The microcapsule shell constructed from tobacco pectin, γ-polyglutamic acid, and tea polyphenols ensures continuous inhibition of soil microorganisms and fungi on the outer wall of the container. (5) Moisture absorption and dehumidification equilibrium time: Record the time when the ambient humidity is 80% to 50%, and the test results are shown in Table 3; (6) Substrate nutrient preservation effect: The tobacco-specific substrate was placed in the seed tray, and the experimental temperature was 25℃-30℃. After 30 days of planting tobacco seeds, the pH and EC values ​​of the tobacco-specific substrate were tested. The test results are shown in Table 3. Table 3: Statistical data on the application of seedling trays in planting in Examples 4-6 and Comparative Examples 5-9 Original matrix 5.66 921 - Example 4 5.82 891 28 Example 5 5.77 899 25 Example 6 5.80 896 27 Comparative Example 5 6.35 791 45 Comparative Example 6 6.18 815 40 Comparative Example 7 6.52 756 55 Comparative Example 8 6.03 842 38 Comparative Example 9 6.22 808 42 The physicochemical properties of the substrate in the seedling trays prepared in Examples 4-6 of this application change little, not only because the degradation of substances in the seedling trays replenishes nutrients, but also because the porous structure in the seedling trays effectively reduces nutrient loss. The moisture absorption and desiccation equilibrium time of the seedling trays prepared in Examples 4-6 of this application is controlled at 25-30 minutes, ensuring that the seedling trays do not desiccate too quickly, leading to easy drying of the substrate; nor do they desiccate too slowly, leading to easy water accumulation in the substrate.

[0054] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method of preparing a full-degradable tobacco seedling plug, characterized by, Includes the following steps: Plant fiber pulp, synergist, tobacco cellulose nanocrystals, functional additives, and water are blended to prepare a slurry; the slurry is then molded to obtain fully degradable tobacco seedling trays; the mass ratio of the plant fiber pulp, synergist, tobacco cellulose nanocrystals, and functional additives is 100:5-25:0.06-0.3:0.5-1.5; the functional additives include dispersants and pH adjusters; the mass ratio of the dispersant to the pH adjuster is 0.5-1:0.2-0.6; The preparation method of the synergist includes the following steps: S1: Add calcium-based bentonite, diatomaceous earth, and deionized water to a reaction vessel and mix. Add tobacco lignin, control the temperature at 65-75℃, and react for 2-4 hours under stirring to obtain a modified clay dispersion. Oxidized hydroxypropyl starch, KH550, and deionized water were added to a reaction flask and dispersed. The mixture was activated for 0.5-1 h under stirring at a controlled temperature of 35-40℃. Tobacco pectin was added, and the mixture was kept warm and stirred for 20-40 min. The mixture was then filtered, washed, and dried to obtain reinforced starch gel. S2: Add the enhanced starch glue and deionized water to the reaction vessel and disperse them. Control the temperature at 35-40℃, add sodium lignosulfonate and trehalose, keep warm and stir for 0.5-1h, add the modified clay dispersion and stir, add the antibacterial microcapsule powder and stir, adjust the water content of the system to 30-40%, and obtain the synergist. The preparation method of the antibacterial microcapsule powder includes the following steps: A1: Add β-cyclodextrin, tobacco pectin, and deionized water to a reaction vessel, control the temperature at 45-50℃ and stir for 0.5-1h, control the temperature at 35-40℃, add tobacco stem extract, stir for 3-6h, centrifuge, wash, and dry to obtain inclusion complex; A2: Chitosan and acetic acid solution are added to the reaction vessel for dispersion, inclusion complex is added for dispersion, γ-polyglutamic acid, tea polyphenols and deionized water are mixed and added to the reaction vessel, the temperature is controlled at 20-30℃, crosslinking is carried out for 1-3 hours, and then dried to obtain antibacterial microcapsule powder. The preparation method of tobacco stalk extract includes the following steps: tobacco stalk waste, ethanol, and deionized water are added to a reaction flask for ultrasonic-assisted extraction, followed by filtration and rotary evaporation for concentration to obtain tobacco stalk extract; The addition ratio of β-cyclodextrin, tobacco pectin, deionized water, and tobacco stalk extract in A1 is 10g: 0.8-1.2g: 50-100mL: 5-8g; In A2, the acetic acid solution is a 1 mol / L aqueous solution of acetic acid; the addition ratio of chitosan, acetic acid solution, inclusion complex, γ-polyglutamic acid, tea polyphenols, and deionized water is 10g: 150-200mL: 16-18g: 0.8-1: 0.25-0.35: 100-120mL.

2. The method for preparing a fully degradable tobacco seedling tray according to claim 1, characterized in that, The addition ratio of calcium-based bentonite, diatomaceous earth, deionized water, and tobacco lignin in S1 is 5-6g: 4g: 80-100mL: 1-1.2g; The addition ratio of oxidized hydroxypropyl starch, KH550, deionized water, and tobacco pectin in S1 is 4g:0.1-0.12g:10-20mL:0.12-0.15g.

3. The method for preparing a fully degradable tobacco seedling tray according to claim 1, characterized in that, The addition ratio of reinforced starch glue, deionized water, sodium lignosulfonate, trehalose, modified clay dispersion, and antibacterial microcapsule powder in S2 is 4g: 10-20mL: 0.3-0.6g: 0.1-0.2g: 100-120g: 4-4.5g.

4. The method for preparing a fully degradable tobacco seedling tray according to claim 1, characterized in that, The method for preparing the plant fiber pulp includes the following steps: composting and fermenting plant straw, and mechanically disassembling it to obtain plant fiber pulp.

5. The method for preparing a fully degradable tobacco seedling tray according to claim 4, characterized in that, The specific process of composting fermentation is as follows: after crushing the plant straw, the moisture content is adjusted to 60-70%, and 0.1-1.5% of the total weight of the plant straw is inoculated with a high-temperature fermentation agent for straw to carry out biological fermentation. The process parameters for the bio-fermentation are: controlling the composting temperature at 40℃-75℃ and composting for 6-10 days. The plant straw is obtained by mixing one or two of rice straw and sugarcane bagasse in any ratio.

6. The method for preparing a fully degradable tobacco seedling tray according to claim 1, characterized in that, The molding process is a negative pressure suction filtration molding process, which includes slurry suction, dehumidification, wet blank transfer, and demolding.

7. A fully degradable tobacco seedling tray, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.