Seedling raising method for improving uniformity and seedling quality of tobacco floating seedling raising

Abstract

The invention belongs to the technical field of seedling culture. According to the seedling raising method for improving the tobacco floating seedling raising uniformity and the seedling quality, during seedling raising, a special seedling raising substrate and a special nutrient solution are adopted; the special seedling raising substrate is prepared from the following components in parts by weight: 100 parts of excrement plant extraction residue pyrolysis compound, 3-6 parts of turf, 10-12 parts of corn straw, 18-20 parts of vermiculite, 13-16 parts of river sand and 8-12 parts of coco coir, the special nutrient solution is prepared from 1000g of water, 0.3 to 0.5 g of acorus calamus and goldhair hedyotis herb aqueous extract fermented materials, 0.2 to 0.4 g of calcium ammonium nitrate, 0.6 to 0.8 g of potassium sulfate, 0.3 to 0.5 g of ammonium bicarbonate, 0.3 to 0.5 part of ammonium dihydrogen phosphate, 1 to 2 mg of boric acid and 1 to 2 mg of zinc sulfate. According to the seedling raising method, the uniformity of the tobacco seedlings can be effectively improved on the basis of obviously shortening the seedling emergence time and improving the seedling emergence rate, the seedling strengthening index and the disease resistance.

Description

Technical Field

[0001] This invention belongs to the field of seedling technology, specifically relating to a seedling method for improving the uniformity and quality of tobacco floating seedlings. Background Technology

[0002] As a core component of modern tobacco cultivation, floating seedling raising technology directly impacts seedling uniformity after transplanting, as well as disease control effectiveness and final yield and quality. Uniform seedlings reduce the need for replanting, lower management costs, and ensure synchronized growth, avoiding nutrient competition or inconsistent maturity due to individual differences. Furthermore, it facilitates large-scale transplanting and standardized management, thereby enhancing the industrial usability and market competitiveness of tobacco leaves.

[0003] Currently, the main technical means to improve the uniformity of tobacco seedlings include leaf pruning, water and fertilizer management, and temperature and humidity control. These methods are usually carried out using conventional seedling substrates or nutrient solutions, which have drawbacks such as low germination rate, low seedling vigor index, and poor disease resistance. Therefore, research on improving the uniformity of tobacco seedlings should be conducted based on production plans that can achieve good seedling quality. However, at present, there is a lack in this field of tobacco floating seedling cultivation methods that possess both excellent germination rate, seedling vigor index, and disease resistance, as well as excellent seedling uniformity. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a seedling raising method that improves the uniformity and seedling quality of tobacco floating seedling raising. This method can improve the uniformity of tobacco seedlings, increase the stem-to-height ratio and reduce the stem-to-leaf weight ratio, while shortening the emergence time and having excellent emergence rate and strong seedling index.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for improving the uniformity and quality of tobacco seedlings in floating seedling cultivation, wherein the method uses a special seedling substrate and a special nutrient solution during seedling cultivation;

[0007] The special seedling substrate, by weight, comprises the following components: 100 parts of manure plant extract residue pyrolysis complex, 3-6 parts of peat moss, 10-12 parts of corn stalks, 18-20 parts of vermiculite, 13-16 parts of river sand, and 8-12 parts of coconut coir.

[0008] The special nutrient solution comprises the following components: 1000g water, 0.3-0.5g fermented water extract of Acorus calamus and Aristolochia debilis, 0.2-0.4g calcium ammonium nitrate, 0.6-0.8g potassium sulfate, 0.3-0.5g ammonium bicarbonate, 0.3-0.5 parts ammonium dihydrogen phosphate, 1-2mg boric acid, and 1-2mg zinc sulfate;

[0009] The preparation method of the pyrolysis complex of manure plant extract residue is as follows:

[0010] (1) Mix chicken manure, cow manure and water extract residue of golden ear grass in a weight ratio of 7:3:3 to 5, inoculate with Bacillus subtilis B115 for fermentation, and ferment for 12 to 16 hours.

[0011] (2) Mix the calamus water extract with the product obtained in step (1) at a volume ratio of 3 to 5:10, and pyrolyze at 230 to 250°C and 5 to 8 MPa to obtain the solid phase.

[0012] The preparation method of the fermentation pyrolysis product of the aqueous extract of Acorus calamus and Aristolochia debilis is as follows: Acorus calamus and Aristolochia debilis are used as extraction substrates and water is used as extraction agent at a weight ratio of 3 to 5:1. After separation, the residue phase is obtained. Then, the obtained residue phase is used as fermentation substrate and Bacillus subtilis B115 is used as fermentation bacteria for fermentation to obtain the product.

[0013] The Bacillus subtilis B115 has the accession number CGMCC NO.1210.

[0014] During their research on floating seedling cultivation of tobacco, the inventors developed a specialized seedling substrate and nutrient solution for this purpose (the inventors have separately applied for a patent; the relevant preparation methods and main experimental results are described in the preliminary experiment section). This addresses the industry's difficulty in improving tobacco disease resistance through the development of seedling substrates or nutrient solutions, and significantly improves seedling emergence and robustness. However, besides seedling emergence rate, robustness index, and disease resistance, improving the industrial value of seedling cultivation also requires consideration of seedling uniformity, i.e., the coefficient of variation of plant height and leaf number. If the seedling uniformity is poor, production personnel need to classify the seedlings, which is not only time-consuming and labor-intensive but also reduces the economic value of the resulting seedlings. Therefore, improving seedling uniformity is also a key focus of research in this field.

[0015] During their research, the inventors discovered that whether using only their proprietary seedling substrate and nutrient solution, or a combination of both, resulted in seedlings with relatively uniformity, and the coefficients of variation for plant height and leaf number were both above 20%. Although using the inventors' seedling substrate and nutrient solution can significantly shorten the germination time from the conventional 16-20 days to 9 days and achieve a 100% germination rate, it is not as effective as conventional methods in terms of uniformity.

[0016] Considering the crucial role of manure-plant extract pyrolysis complex in the seedling substrate, fermented water extracts of calamus and golden ear grass in the nutrient solution, and steam-explosion enzymatic hydrolysis fermented product of corn straw in enhancing disease resistance, the inventors initially retained these substances while adjusting other raw materials and conducting research on how to improve the uniformity of tobacco seedlings. Through extensive experimentation, the inventors discovered that by adding a certain proportion of river sand and coconut coir to the seedling substrate they had previously developed, and by removing the steam-explosion enzymatic hydrolysis fermented product of corn straw from the previously developed special nutrient solution, the coefficient of variation for plant height and leaf number could be significantly reduced to below 5%, resulting in tobacco seedlings with a uniformity that met the standard of "uniformity."

[0017] Using river sand as a substrate for floating seedling cultivation is called sand-culture floating seedling cultivation technology. It offers better germination rates and time compared to conventional floating seedling cultivation techniques and can improve seedling resistance to some extent. However, it has limitations in terms of uniformity. For example, Cui Xuelin systematically studied the experimental effects of tobacco floating seedling cultivation in his paper "Experimental Analysis of Tobacco Sand-Cultivation Floating Seedling Cultivation" (DOI:10.3969 / j.issn.1000-6400.2009.04.033.). As shown in the comparative examples of this invention, when river sand was added to the substrate, the uniformity changed to "irregular," with the coefficients of variation for plant height and leaf number reaching 31%, consistent with Cui Xuelin's findings. As shown in Examples 1 to 3 of this invention, adding a certain proportion of coconut coir to river sand can significantly improve the uniformity of tobacco seedlings without substantially affecting germination rate, germination time, seedling vigor index, or disease resistance.

[0018] It is worth mentioning that, during the inventors' preliminary research, the presence of corn straw steam explosion enzymatic hydrolysis fermentation products in the specially developed nutrient solution had a significant impact on achieving the desired technical objectives. In this invention, by removing the corn straw steam explosion enzymatic hydrolysis fermentation products from the nutrient solution based on the newly developed seedling substrate, not only were there no significant effects on germination rate, germination time, seedling vigor index, and disease resistance, but the uniformity of tobacco seedlings was also improved. This indicates that a certain proportion of river sand and coconut coir in the seedling substrate has a certain antagonistic effect on the uniformity of tobacco seedlings compared to the corn straw steam explosion enzymatic hydrolysis fermentation products in the nutrient solution.

[0019] Based on the above findings, as shown in a comparative embodiment of the present invention, after the inventors replaced the nutrient solution with a commercially available ordinary nutrient solution, they found that the uniformity of the obtained tobacco seedlings could not be maintained at the "uniform" level. This indicates that the improved seedling substrate needs to be combined with the nutrient solution developed by the inventors in order for the obtained tobacco seedlings to have excellent uniformity.

[0020] Preferably, in preparing the pyrolysis complex of the manure plant extract residue, the weight ratio of chicken manure, cow manure and golden ear grass water extract residue is 7:3:3, and the volume ratio of calamus water extract to the product obtained in step (1) is 4:10.

[0021] Preferably, in preparing the fermented pyrolysis product of the aqueous extract of calamus and golden ear grass, the weight ratio of calamus to golden ear grass is 4:1, the extraction temperature is 80℃, and the extraction time is 2 hours.

[0022] Preferably, the special seedling substrate comprises, by weight, the following components: 100 parts of manure-plant extract pyrolysis complex, 3 parts of peat moss, 12 parts of corn stalks, 20 parts of vermiculite, 15 parts of river sand, and 10 parts of coconut coir.

[0023] Preferably, the special nutrient solution comprises the following components: 1000g water, 0.4g fermented water extract of calamus and golden ear grass, 0.3g calcium ammonium nitrate, 0.8g potassium sulfate, 0.3g ammonium bicarbonate, 0.4 parts ammonium dihydrogen phosphate, 2mg boric acid, and 2mg zinc sulfate.

[0024] Preferably, when preparing the pyrolysis complex of manure plant extract residue, the inoculum amount of Bacillus subtilis B115 is 5%.

[0025] Preferably, when preparing the fermented pyrolysis product of the water extract of Acorus calamus and Aristolochia debilis, the inoculum amount of Bacillus subtilis B115 is 2%.

[0026] Preferably, the fermentation time for preparing the manure-plant extract pyrolysis complex is 12 hours.

[0027] Preferably, in preparing the fermented pyrolysis product of the aqueous extract of Acorus calamus and Aristolochia debilis, the weight ratio of the extract substrate to water is 1:10.

[0028] Preferably, the pyrolysis is carried out under the following conditions: 230–250°C, 5–8 MPa, and for 30 minutes.

[0029] The beneficial effects of this invention are:

[0030] The seedling raising method of the present invention can significantly shorten the emergence time, increase the emergence rate, seedling vigor index and disease resistance, and effectively reduce the coefficient of variation of plant height and leaf number to improve the uniformity of tobacco seedlings, thereby improving the economic value of tobacco seedling production. Detailed Implementation

[0031] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are still within the scope of protection of the present invention.

[0032] Unless otherwise specified, the raw materials and products used in the following examples and preliminary experimental cases are as follows:

[0033] Cow dung: taken from a local cattle farm in Qujing City;

[0034] Chicken manure: taken from a local chicken farm in Qujing City;

[0035] Vermiculite: Purchased from Lingshou County Yongqi Mineral Products Co., Ltd., product name: vermiculite powder;

[0036] Golden ear grass and calamus: sourced from local Chinese medicinal herb planting base, are fresh whole herbs that have not been processed;

[0037] Ammonium bicarbonate: purchased from Chengdu Sange Chemical Co., Ltd.;

[0038] Calcium ammonium nitrate: Guangxi Zhuangda Fertilizer Co., Ltd.;

[0039] Potassium sulfate: Kunming Shahaobei Trading Co., Ltd.;

[0040] Ammonium dihydrogen phosphate: Jinan Xinchenxu Chemical Co., Ltd.;

[0041] Boric acid and zinc sulfate: both are available in the laboratory.

[0042] Corn stalks: collected from local cornfields;

[0043] River sand: purchased from the local building materials market and sterilized at high temperature before use;

[0044] Coconut coir: Purchased from Shijiazhuang Wofuwo Fertilizer Co., Ltd., brand name "Wofuwo Fertilizer";

[0045] Bacillus subtilis B115, with accession number CGMCC NO.1210, is a publicly disclosed strain and was purchased from the China General Microbiological Culture Collection Center.

[0046] Tobacco seeds: Yunyan 87;

[0047] Example 1

[0048] A seedling raising method for improving the uniformity and quality of tobacco seedlings raised by floating cultivation is disclosed. The method follows the floating seedling raising technique described in the "Technical Specification for Intensive Tobacco Seedling Raising" (GB / T 25241.1—2010). Specialized seedling substrate and nutrient solution are used during the seedling raising process.

[0049] The special seedling substrate, by weight, includes the following components: 100 parts manure plant extract residue pyrolysis complex, 3 parts peat moss, 12 parts corn stalks, 20 parts vermiculite, 15 parts river sand, and 10 parts coconut coir.

[0050] The preparation method of the pyrolysis complex of manure plant extract residue is as follows:

[0051] (1) Chicken manure, cow manure and water extract residue of golden ear grass were mixed in a weight ratio of 7:3:3 and the moisture content was adjusted to 20%. Then, Bacillus subtilis B115 was inoculated at a 5% inoculation rate for fermentation for 12 hours. The preservation number of Bacillus subtilis B115 was CGMCC NO.1210.

[0052] (2) Mix the water extract of calamus with the product obtained in step (1) at a volume ratio of 4:10, and pyrolyze at 250℃ and 5MPa for 30 minutes, and take the solid phase.

[0053] The above components are mixed to obtain a special seedling substrate.

[0054] The special nutrient solution includes the following components: 1000g water, 0.4g fermented water extract of calamus and golden ear grass, 0.3g calcium ammonium nitrate, 0.8g potassium sulfate, 0.3g ammonium bicarbonate, 0.4 parts ammonium dihydrogen phosphate, 2mg boric acid, and 2mg zinc sulfate;

[0055] The preparation method of the fermented aqueous extracts of calamus and golden ear grass is as follows:

[0056] Acorus calamus and Achyranthes bidentata were used as extraction substrates at a weight ratio of 4:1, and water was used as the extraction solvent. The weight ratio of extraction substrate to water was 1:10. The extraction was carried out at 80°C for 2 hours. The extract was then subjected to solid-liquid separation to obtain the residue phase. The obtained residue phase was then used as the fermentation substrate, and Bacillus subtilis B115 was inoculated at an inoculum amount of 2%. Fermentation was carried out at 35°C for 24 hours to obtain the final product.

[0057] Example 2

[0058] A seedling raising method for improving the uniformity and quality of tobacco seedlings raised by floating cultivation is disclosed. The method follows the floating seedling raising technique described in the "Technical Specification for Intensive Tobacco Seedling Raising" (GB / T 25241.1—2010). Specialized seedling substrate and nutrient solution are used during the seedling raising process.

[0059] The special seedling substrate, by weight, includes the following components: 100 parts manure plant extract residue pyrolysis complex, 6 parts peat moss, 10 parts corn stalks, 19 parts vermiculite, 16 parts river sand, and 12 parts coconut coir.

[0060] The preparation method of the pyrolysis complex of manure plant extract residue is as follows:

[0061] (1) Chicken manure, cow manure and water extract residue of golden ear grass were mixed in a weight ratio of 7:3:5 and the moisture content was adjusted to 20%. Then, Bacillus subtilis B115 was inoculated at a 5% inoculation rate for fermentation for 16 hours. The preservation number of Bacillus subtilis B115 was CGMCC NO.1210.

[0062] (2) Mix the water extract of calamus with the product obtained in step (1) at a volume ratio of 3:10, and pyrolyze at 230℃ and 8MPa for 30 minutes, and take the solid phase.

[0063] The above components are mixed to obtain a special seedling substrate.

[0064] The special nutrient solution includes the following components: 1000g water, 0.4g fermented water extract of calamus and golden ear grass, 0.3g calcium ammonium nitrate, 0.8g potassium sulfate, 0.3g ammonium bicarbonate, 0.4 parts ammonium dihydrogen phosphate, 2mg boric acid, and 2mg zinc sulfate;

[0065] The preparation method of the fermented aqueous extracts of calamus and golden ear grass is as follows:

[0066] Acorus calamus and Achyranthes bidentata were used as extraction substrates at a weight ratio of 3:1, and water was used as the extraction solvent. The weight ratio of extraction substrate to water was 1:10. The extraction was carried out at 80°C for 2 hours. The extract was then subjected to solid-liquid separation to obtain the residue phase. The obtained residue phase was then used as the fermentation substrate, and Bacillus subtilis B115 was inoculated at an inoculum amount of 2%. Fermentation was carried out at 35°C for 24 hours to obtain the final product.

[0067] Example 3

[0068] A seedling raising method for improving the uniformity and quality of tobacco seedlings raised by floating cultivation is disclosed. The method follows the floating seedling raising technique described in the "Technical Specification for Intensive Tobacco Seedling Raising" (GB / T 25241.1—2010). Specialized seedling substrate and nutrient solution are used during the seedling raising process.

[0069] The special seedling substrate, by weight, includes the following components: 100 parts manure plant extract residue pyrolysis complex, 6 parts peat moss, 10 parts corn stalks, 19 parts vermiculite, 16 parts river sand, and 12 parts coconut coir.

[0070] The preparation method of the pyrolysis complex of manure plant extract residue is as follows:

[0071] (1) Chicken manure, cow manure and water extract residue of golden ear grass were mixed in a weight ratio of 7:3:4 and the moisture content was adjusted to 20%. Then, Bacillus subtilis B115 was inoculated at a 5% inoculation rate for fermentation for 14 hours. The preservation number of Bacillus subtilis B115 was CGMCC NO.1210.

[0072] (2) Mix the water extract of calamus with the product obtained in step (1) at a volume ratio of 5:10, and pyrolyze at 240℃ and 6MPa for 30 minutes, and take the solid phase.

[0073] The above components are mixed to obtain a special seedling substrate.

[0074] The special nutrient solution includes the following components: 1000g water, 0.4g fermented water extract of calamus and golden ear grass, 0.3g calcium ammonium nitrate, 0.8g potassium sulfate, 0.3g ammonium bicarbonate, 0.4 parts ammonium dihydrogen phosphate, 2mg boric acid, and 2mg zinc sulfate;

[0075] The preparation method of the fermented aqueous extracts of calamus and golden ear grass is as follows:

[0076] Acorus calamus and Achyranthes bidentata were used as extraction substrates at a weight ratio of 5:1, and water was used as the extraction solvent. The weight ratio of extraction substrate to water was 1:10. The extraction was carried out at 80°C for 2 hours. The extract was then subjected to solid-liquid separation to obtain the residue phase. The obtained residue phase was then used as the fermentation substrate, and Bacillus subtilis B115 was inoculated at an inoculum amount of 2%. Fermentation was carried out at 35°C for 24 hours to obtain the final product.

[0077] Comparative Example 1

[0078] Compared with Example 1, no coconut coir was added in the preparation of the special seedling substrate, but otherwise it was the same as Example 1.

[0079] Comparative Example 2

[0080] Compared with Example 1, no river sand was added in the preparation of the special seedling substrate, but the rest was the same as in Example 1.

[0081] Comparative Example 3

[0082] Compared with Example 1, when preparing the special seedling substrate, the weight of river sand was adjusted to 5 parts and the weight of coconut coir was adjusted to 20 parts, while the rest remained the same as in Example 1.

[0083] Comparative Example 4

[0084] Except for using Xinye brand special seedling fertilizer produced by Sichuan Jinye Fertilizer Co., Ltd. to prepare nutrient solution to replace the special nutrient solution, everything else is the same as in Example 1.

[0085] Preliminary Experiment Example 1

[0086] Prior to this invention, the inventors developed a seedling substrate suitable for floating tobacco seedling cultivation, which offers advantages such as early emergence, high emergence rate, high seedling vigor index, and strong disease resistance. The preparation method of this seedling substrate is as follows:

[0087] Prepare the components by weight:

[0088] 100 parts of pyrolysis complex of manure plant extract residue, 4 parts of peat moss, 15 parts of corn stalks, and 18 parts of vermiculite;

[0089] The preparation method of the pyrolysis complex of manure plant extract residue is as follows:

[0090] (1) Chicken manure, cow manure and water extract residue of golden ear grass were mixed in a weight ratio of 7:3:3 and the moisture content was adjusted to 20%. Then, Bacillus subtilis B115 was inoculated at a 5% inoculation rate for fermentation for 12 hours. The preservation number of Bacillus subtilis B115 was CGMCC NO.1210.

[0091] (2) Mix the water extract of calamus with the product obtained in step (1) at a volume ratio of 4:10, and pyrolyze at 250℃ and 5MPa for 30 minutes, and take the solid phase.

[0092] The above components are mixed to obtain a tobacco floating seedling substrate.

[0093] Meanwhile, prior to this invention, the inventors had also developed a nutrient solution suitable for tobacco floating seedling cultivation. This solution also exhibits advantages such as early emergence, high emergence rate, high seedling vigor index, and strong disease resistance in tobacco seedling cultivation. The preparation method of this nutrient solution is as follows:

[0094] 1. Preparation of fermented aqueous extracts of Acorus calamus and Acorus gramineus:

[0095] Acorus calamus and Achyranthes bidentata were used as extraction substrates at a weight ratio of 4:1, and water was used as the extraction solvent. The weight ratio of extraction substrate to water was 1:10. The extraction was carried out at 80°C for 2 hours. The extract was then subjected to solid-liquid separation to obtain the residue phase. The obtained residue phase was then used as the fermentation substrate, and Bacillus subtilis B115 was inoculated at an inoculum amount of 2%. Fermentation was carried out at 35°C for 24 hours to obtain the final product.

[0096] 2. Preparation of corn stalk steam explosion enzymatic hydrolysis fermentation product:

[0097] The crushed corn stalks were passed through saturated steam and treated at 1.2 MPa for 5 minutes; then placed in a hemicellulase aqueous solution (800 IU / mL) and treated at 30°C for 1 hour. After rinsing with water, Bacillus subtilis B115 was inoculated at an inoculation rate of 2% and fermented at 35°C for 24 hours to obtain the final product.

[0098] 3. Mix the following components by weight:

[0099] 1000g water, 0.4g fermented water extract of Acorus calamus and Aristolochia debilis, 0.2 parts steam-explosion enzymatic hydrolysis fermented corn stalks, 0.3g calcium ammonium nitrate, 0.8g potassium sulfate, 0.3g ammonium bicarbonate, 0.4 parts ammonium dihydrogen phosphate, 2mg boric acid, 2mg zinc sulfate.

[0100] Experiments revealed that, following the floating seedling raising technique outlined in the "Technical Specification for Intensive Tobacco Seedling Raising" (GB / T 25241.1—2010), when using the aforementioned seedling substrate, even with a common nutrient solution (Xinye brand special seedling fertilizer produced by Sichuan Jinye Fertilizer Co., Ltd.), the germination time was only 9 days, the germination rate reached 100%, the seedling vigor index reached 0.55, and the black shank disease severity index was only 24.7%. Similarly, when using the aforementioned nutrient solution, even with a conventional seedling substrate composed of peat moss, vermiculite, and expanded perlite mixed in a volume ratio of 3:1:1, the germination rate reached 100% on day 11, the seedling vigor index reached 0.51, and the black shank disease severity index was only 28.5. However, the tobacco seedlings obtained by the two floating seedling raising schemes mentioned above were not uniform. According to the classification of "Tobacco Agronomic Trait Survey Methods" (YC / T 142-1998), they were only at the "relatively uniform" level, and the coefficients of variation for plant height and number of leaves were 23% and 24%, respectively.

[0101] Preliminary Experiment Example 2

[0102] Based on Preliminary Experiment Example 1, the inventors used the same seedling substrate and nutrient solution as in Preliminary Experiment Example 1 when conducting floating seedling cultivation, and followed the floating seedling cultivation method in the "Technical Specification for Intensive Tobacco Seedling Cultivation" (GB / T 25241.1—2010). Under this scheme, referring to the "Methods for Investigating Agronomic Traits of Tobacco" (YC / T 142-1998), the uniformity was still "relatively uniform," and the coefficients of variation for plant height and number of leaves still reached 21%.

[0103] Experimental Example 1

[0104] For Examples 1-3 and Comparative Examples 1-4, this experimental example investigated seedling emergence rate, seedling vigor index, stem-to-leaf weight ratio, stem diameter-to-plant height ratio, uniformity, and disease resistance. The relevant testing protocols are as follows (unless otherwise specified, the testing methods used in the aforementioned Preliminary Experiment 1 and Preliminary Experiment 2 are the same as those used in this experimental example):

[0105] (1) Seedling emergence rate and seedling vigor index test

[0106] The floating seedling raising technique shall be carried out in accordance with the "Technical Specification for Intensive Seedling Raising of Tobacco" (GB / T 25241.1—2010).

[0107] The germination rate was investigated 7, 9, and 11 days after sowing.

[0108] (2) Seedling quality

[0109] After the seedling raising was completed, 20 tobacco seedlings with similar growth and development were randomly selected from the seedling trays of each different treatment group. After cleaning and removing impurities, the seedlings were dried with absorbent paper. The above-ground and underground parts of the seedlings were separated, and the fresh weight was weighed. The stem diameter and plant height were measured. After drying, the dry weight was weighed. At the same time, the stem dry weight and leaf dry weight were measured.

[0110] Strong seedling index = (stem diameter / plant height + root dry weight / aboveground dry weight) × total plant dry weight;

[0111] Stem-to-leaf weight ratio: stem weight ÷ leaf weight;

[0112] Stem thickness to plant height ratio: stem thickness ÷ plant height;

[0113] Uniformity: Refer to the "Methods for Investigating Agronomic Traits of Tobacco" (YC / T 142-1998) to investigate uniformity during the budding stage. Plants with a coefficient of variation of less than 10% for plant height and number of leaves are considered uniform, those with a coefficient of variation of more than 25% are considered irregular, and those with a coefficient of variation between 10% and 25% are considered relatively uniform.

[0114] (3) Black shank resistance test

[0115] After the tobacco seedlings were pruned once (seedling age 40), 60 seedlings were selected from each group and transplanted into new floating trays. The preserved black shank strain was activated, inoculated into oat liquid medium, and cultured in a shaker at 28℃ and 150 rpm for 2 weeks. A 0.1% potassium nitrate solution was added to prepare a solution with a concentration of 1×10⁻⁶. 8 A suspension of zoospores at cfu / mL was prepared. The zoospore suspension was inoculated using the stem base wound inoculation method. After inoculation, the seedling trays were placed in a constant temperature tank at 28℃, and water was sprayed twice daily to maintain high humidity and induce disease. Disease incidence and disease index were calculated starting 5 days after inoculation and repeated every 3 days.

[0116] The experimental results are shown in Tables 1 to 3.

[0117] Table 1

[0118]

[0119] Table 2

[0120]

[0121] Table 3

[0122]

[0123] As shown in Table 1, the seedling raising methods of Examples 1-3 of the present invention can also achieve a 100% germination rate by day 9. It is worth mentioning that Comparative Examples 1-4 also have excellent results in terms of germination; at the same time, as shown in Table 3, Examples 1-3 and Comparative Examples 1-4 are not significantly different in terms of disease resistance. These technical effects are attributed to the seedling substrate previously developed by the inventors as described in Preliminary Experiment Example 1.

[0124] However, as shown in Table 2, apart from a small difference in the seedling vigor coefficient, Examples 1-3 showed significant differences from Comparative Examples 1-4 in stem-to-leaf weight ratio, stem-to-height ratio, and uniformity. Examples 1-3 had lower stem-to-leaf weight ratio and stem-to-height ratio, resulting in shorter and stronger tobacco seedlings; in particular, the coefficients of variation for plant height and leaf number in Examples 1-3 were significantly lower than those in Comparative Examples 1-4, indicating excellent uniformity.

[0125] The experimental results above show that the present invention has developed a seedling method that can improve the uniformity of tobacco seedlings, increase the stem-to-plant-height ratio and reduce the stem-to-leaf weight ratio, while shortening the emergence time and having excellent emergence rate and strong seedling index.

Claims

1. A method for improving the uniformity and seedling quality of tobacco floating seedling cultivation, characterized in that, The method uses a special seedling substrate and a special nutrient solution during seedling cultivation. The special seedling substrate, by weight, comprises the following components: 100 parts of manure plant extract residue pyrolysis complex, 3-6 parts of peat moss, 10-12 parts of corn stalks, 18-20 parts of vermiculite, 13-16 parts of river sand, and 8-12 parts of coconut coir. The special nutrient solution comprises the following components: 1000g water, 0.3-0.5g fermented water extract of Acorus calamus and Aristolochia debilis, 0.2-0.4g calcium ammonium nitrate, 0.6-0.8g potassium sulfate, 0.3-0.5g ammonium bicarbonate, 0.3-0.5 parts ammonium dihydrogen phosphate, 1-2mg boric acid, and 1-2mg zinc sulfate; The preparation method of the pyrolysis complex of manure plant extract residue is as follows: (1) Mix chicken manure, cow manure and water extract residue of golden ear grass in a weight ratio of 7:3:3 to 5, inoculate with Bacillus subtilis B115 for fermentation, and ferment for 12 to 16 hours. (2) Mix the calamus water extract with the product obtained in step (1) at a volume ratio of 3 to 5:10, and pyrolyze at 230 to 250°C and 5 to 8 MPa to obtain the solid phase. The preparation method of the fermentation pyrolysis product of the aqueous extract of Acorus calamus and Aristolochia debilis is as follows: Acorus calamus and Aristolochia debilis are used as extraction substrates and water is used as extraction agent at a weight ratio of 3 to 5:

1. After separation, the residue phase is obtained. Then, the obtained residue phase is used as fermentation substrate and Bacillus subtilis B115 is used as fermentation bacteria for fermentation to obtain the product. The Bacillus subtilis B115 has the accession number CGMCC NO.1210.

2. The seedling raising method for improving the uniformity and seedling quality of tobacco floating seedling raising according to claim 1, characterized in that, In preparing the fecal plant extract pyrolysis complex, the weight ratio of chicken manure, cow manure and golden ear grass water extract residue is 7:3:3, and the volume ratio of calamus water extract to the product obtained in step (1) is 4:

10.

3. The seedling raising method for improving the uniformity and seedling quality of tobacco floating seedling raising according to claim 2, characterized in that, In preparing the fermented pyrolysis product of the aqueous extract of Acorus calamus and Aristolochia debilis, the weight ratio of Acorus calamus to Aristolochia debilis was 4:1, the extraction temperature was 80℃, and the extraction time was 2 hours.

4. A method for improving the uniformity and seedling quality of tobacco floating seedling cultivation according to claim 2 or 3, characterized in that, The special seedling substrate, by weight, comprises the following components: 100 parts of manure-plant extract pyrolysis complex, 3 parts of peat moss, 12 parts of corn stalks, 20 parts of vermiculite, 15 parts of river sand, and 10 parts of coconut coir.

5. The seedling raising method for improving the uniformity and seedling quality of tobacco floating seedling raising according to claim 4, characterized in that, The special nutrient solution comprises the following components: 1000g water, 0.4g fermented water extract of calamus and golden ear grass, 0.3g calcium ammonium nitrate, 0.8g potassium sulfate, 0.3g ammonium bicarbonate, 0.4 parts ammonium dihydrogen phosphate, 2mg boric acid, and 2mg zinc sulfate.

6. A method for improving the uniformity and seedling quality of tobacco floating seedling cultivation according to claim 1 or 5, characterized in that, In preparing the pyrolysis complex of the manure plant extract residue, the inoculum amount of Bacillus subtilis B115 was 5%.

7. The method for improving the uniformity and seedling quality of tobacco floating seedling cultivation according to claim 6, characterized in that, In preparing the fermentation pyrolysis product of the aqueous extract of Acorus calamus and Aristolochia debilis, the inoculum amount of Bacillus subtilis B115 was 2%.

8. The seedling raising method for improving the uniformity and seedling quality of tobacco floating seedling raising according to claim 7, characterized in that, The fermentation time for preparing the pyrolysis complex of manure and plant extract residue is 12 hours.

9. A method for improving the uniformity and seedling quality of tobacco floating seedling cultivation according to claim 7, characterized in that, In preparing the fermented pyrolysis product of the aqueous extract of Acorus calamus and Aristolochia debilis, the weight ratio of the extract substrate to water was 1:

10.

10. A method for improving the uniformity and seedling quality of tobacco floating seedling cultivation according to claim 8 or 9, characterized in that, The pyrolysis is carried out under the following conditions: 230–250°C, 5–8 MPa, and a pyrolysis time of 30 minutes.

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