Flue-cured tobacco production method based on timely early planting

Abstract

The invention relates to a flue-cured tobacco production method based on timely early planting, and the flue-cured tobacco production method comprises the following steps: S1, before flue-cured tobacco transplanting, organic-inorganic compound fertilizer is applied into soil in furrow application or hole application, the organic-inorganic compound fertilizer is composed of water-soluble fertilizer, oil cake organic fertilizer and wormcast organic fertilizer, and the mass ratio of the water-soluble fertilizer to the oil cake organic fertilizer to the wormcast organic fertilizer is 1: 2.4-2.6: 2-2.6; s2, transplanting tobacco seedlings under the condition that the daily average temperature of the field is lower than 15 DEG C, and performing foliage spraying on the tobacco seedlings by using a low-temperature growth-promoting microbial agent. The method can significantly reduce the diseases of the flue-cured tobacco leaves, improve the coordination of main chemical components of the tobacco leaves, increase the content of aroma substances and improve the sensory quality of the tobacco leaves.

Description

Technical Field

[0001] The invention belongs to the technical field of flue-cured tobacco production under adverse conditions, and relates to a flue-cured tobacco production method based on timely early planting. Background Art

[0002] With the internationalization of cigarette brands and the continuous upgrading of big brand effects, the cigarette industry has an increasing demand for high-quality tobacco raw materials. Early planting of flue-cured tobacco is crucial to improving tobacco yield and quality. First, early planting can ensure that tobacco leaves mature and turn yellow under the best climatic conditions, avoiding the adverse effects of high or low temperatures on tobacco growth in the later period; second, early planting can extend the growth period of tobacco leaves, which is conducive to the full maturity of tobacco leaves and improves the intrinsic quality of tobacco leaves; third, early planting can help reduce the occurrence of diseases and insect pests, because the early climate is relatively mild and the activities of diseases and insect pests are not frequent, which is conducive to taking prevention and control measures; fourth, early planting can better utilize soil moisture and nutrients, especially in arid areas, early planting helps tobacco seedlings make full use of spring rain and reduce irrigation needs; fifth, early planting can increase the yield and quality of tobacco leaves, thereby increasing the economic benefits of tobacco farmers. In summary, timely early planting is an important link in flue-cured tobacco production, which is of great significance for ensuring the yield and quality of tobacco leaves.

[0003] How to ensure high-quality and high-yield of flue-cured tobacco planted early in time has always been a technical problem that the flue-cured tobacco industry has been committed to solving. Summary of the invention

[0004] The present invention provides a flue-cured tobacco production method based on timely early planting, which fully promotes the growth, high quality and high yield of flue-cured tobacco under low temperature stress by processing and regulating tobacco seedlings, soil and tobacco leaves.

[0005] The present invention relates to a flue-cured tobacco production method, comprising:

[0006] S1: Before transplanting flue-cured tobacco, an organic-inorganic compound fertilizer is applied into the soil by strip application or hole application, wherein the organic-inorganic compound fertilizer is composed of water-soluble fertilizer, oil cake organic fertilizer, and earthworm castings organic fertilizer, wherein the mass ratio of the water-soluble fertilizer, the oil cake organic fertilizer, and the earthworm castings organic fertilizer is 1:2.4-2.6:1.6-2.6;

[0007] S2: When the average daily field temperature is below 15°C, transplant tobacco seedlings and spray the leaves with low-temperature growth-promoting bacteria.

[0008] In some embodiments, the flue-cured tobacco production method further comprises:

[0009] S3: Fresh tobacco leaves are harvested 5-7 days earlier than the conventional harvest. At this time, the leaves are obviously chlorotic, the hairs fall off, the main and branch veins turn white, and more than 90% of the leaves reach a suitable maturity;

[0010] S4: Fresh tobacco leaves are roughly divided into three categories: unripe, ripe and overripe, and then sorted into poles, with 130 to 150 leaves per pole;

[0011] S5: The same layer and the same quality are loaded on the kang, unripe tobacco leaves are loaded on the low temperature layer, overripe tobacco leaves are loaded on the high temperature layer, and other layers are loaded with moderately ripe tobacco leaves. The loading volume is 15% to 25% higher than the conventional one.

[0012] S6: Baking. Compared with the conventional baking process, the main yellowing temperature of tobacco leaves is increased by 1℃~2℃, the wet bulb temperature during the yellowing and color fixing periods is increased by 0.5℃~1℃, the baking time during the yellowing period is shortened by 6~10h, and the baking time during the color fixing period is extended by 8~12h.

[0013] In some embodiments, the S6 comprises:

[0014] S 6-1 After ignition, the dry bulb temperature is raised to 34.5°C and the wet bulb temperature is 34°C at a heating rate of 1°C / h, and the tobacco leaves in the high temperature layer are baked at a steady temperature until they turn 10% to 20% yellow.

[0015] S 6-2 , raise the dry bulb temperature to 36℃ and the wet bulb temperature to 35.5℃ at a heating rate of 1℃ / h, and bake at a steady temperature until the high temperature layer tobacco leaves turn 20% to 30% yellow and slightly soften;

[0016] S 6-3 , raise the dry bulb temperature to 39°C at a heating rate of 1°C / h, stabilize the wet bulb temperature at 37-38°C (e.g. 37.5°C), start the circulating fan at a low gear, and bake at a steady temperature until the high-temperature layer tobacco leaves turn 70% to 80% yellow and the leaves become soft;

[0017] S 6-4 , raise the dry-bulb temperature to 41°C at a rate of 1°C / 2h, and the wet-bulb temperature to 37-38°C (e.g. 37.5°C), and bake at a steady temperature until the tobacco leaves turn 80% to 90% yellow and the main veins become slightly soft;

[0018] S 6-5 , raise the dry bulb temperature to 43℃ at a heating rate of 1℃ / 3h, stabilize the wet bulb temperature at 37.5℃, and bake at a steady temperature until the high-temperature layer tobacco leaves are fully yellowed, the tips are curled, and the leaves are more than 1 / 4 dry;

[0019] S 6-6 , raise the dry bulb temperature to 46℃ and the wet bulb temperature to 37.5℃ at a heating rate of 1℃ / 2~3h, and bake at a steady temperature until most of the main ribs of the high-temperature layer tobacco leaves turn yellow and more than 1 / 3 of the leaves are dry;

[0020] S 6-7, raise the dry bulb temperature to 48℃ and the wet bulb temperature to 38.5℃ at a heating rate of 1℃ / 2~3h, and bake at a steady temperature until the main tendons of the high-temperature layer tobacco leaves turn yellow, the leaves are more than 1 / 2 dry, and are in a small roll state;

[0021] S 6-8 , raise the dry bulb temperature to 51℃ and the wet bulb temperature to 39℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature until the high-temperature layer tobacco leaves are more than 2 / 3 dry, and the main tendons of the tobacco leaves on the whole kang turn yellow and shrink significantly;

[0022] S 6-9 , raise the dry bulb temperature to 53℃ and the wet bulb temperature to 39.5℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature until the whole tobacco leaves are dry and rolled into large rolls, and the main tendons of the high-temperature layer are dry by more than 1 / 3;

[0023] S 6-10 , raise the dry bulb temperature to 60℃ and the wet bulb temperature to 40℃ at a heating rate of 1℃ / h, and bake at a steady temperature until the main tendons of the high-temperature layer tobacco leaves are more than 1 / 2 dry;

[0024] S 6-11 , raise the dry bulb temperature to 68℃ and the wet bulb temperature to 41℃ at a heating rate of 1℃ / h, and bake at a steady temperature until the tobacco leaves on the kang are completely dry.

[0025] In some embodiments, the S6 comprises:

[0026] S 6-1 After ignition, the dry bulb temperature is raised to 34.5°C at a rate of 1°C / h, and the wet bulb temperature is 34°C. The tobacco leaves are baked at a constant temperature for 2 hours until the high temperature layer turns 10% to 20% yellow.

[0027] S 6-2 , raise the dry bulb temperature to 36℃ and the wet bulb temperature to 35.5℃ at a heating rate of 1℃ / h, and bake at a steady temperature for 3 hours until the tobacco leaves in the high temperature layer turn 20% to 30% yellow and become slightly soft;

[0028] S 6-3 , raise the dry bulb temperature to 39°C at a rate of 1°C / h, stabilize the wet bulb temperature at 37-38°C (e.g. 37.5°C), start the circulating fan at low speed, and bake at a steady temperature for 15-20h, until the high-temperature layer tobacco leaves turn 70% to 80% yellow and become soft;

[0029] S 6-4 , raise the dry-bulb temperature to 41°C at a rate of 1°C / 2h, and the wet-bulb temperature to 37-38°C (e.g. 37.5°C), and bake at a steady temperature for 10-15h until the tobacco leaves turn 80% to 90% yellow and the main veins become slightly soft;

[0030] S 6-5, raise the dry bulb temperature to 43℃ at a rate of 1℃ / 3h, stabilize the wet bulb temperature at 37.5℃, and bake at a steady temperature for 8-12h until the high temperature layer tobacco leaves turn yellow, curl at the tip, and dry more than 1 / 4 of the leaves;

[0031] S 6-6 , raise the dry bulb temperature to 46℃ and the wet bulb temperature to 37.5℃ at a rate of 1℃ / 2~3h, and bake at a steady temperature for 8~12h until most of the main ribs of the high temperature layer tobacco leaves turn yellow and more than 1 / 3 of the leaves are dry;

[0032] S 6-7 , raise the dry bulb temperature to 48℃ and the wet bulb temperature to 38.5℃ at a rate of 1℃ / 2~3h, and bake at a steady temperature for 8~12h until the main tendons of the high-temperature layer tobacco turn yellow, the leaves are more than 1 / 2 dry, and are in a small roll state;

[0033] S 6-8 , raise the dry bulb temperature to 51℃ and the wet bulb temperature to 39℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 3-5h until the high temperature layer of tobacco leaves is more than 2 / 3 dry, and the main tendons of the tobacco leaves on the whole kang turn yellow and shrink significantly;

[0034] S 6-9 , raise the dry bulb temperature to 53℃ and the wet bulb temperature to 39.5℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 12 to 18h until the whole tobacco leaves are dry and rolled into large rolls, and the main tendons of the high-temperature layer are dried by more than 1 / 3;

[0035] S 6-10 , raise the dry bulb temperature to 60℃ and the wet bulb temperature to 40℃ at a heating rate of 1℃ / h, and bake at a steady temperature for 4-5h until the main tendons of the high-temperature layer tobacco leaves are more than 1 / 2 dry;

[0036] S 6-11 , raise the dry-bulb temperature to 68°C and the wet-bulb temperature to 41°C at a heating rate of 1°C / h, and bake at a steady temperature for 20 to 25 hours until the tobacco leaves on the kang are completely dry.

[0037] In some embodiments, the mass ratio of the water-soluble fertilizer, oil cake organic fertilizer, and earthworm castings organic fertilizer is 1:2.4-2.6:2-2.6, for example, 1:2.5:2.5.

[0038] In some embodiments, the mass content ratio of nitrogen calculated as N, phosphorus calculated as P2O5, and potassium calculated as K2O in the water-soluble fertilizer is 1:1:2.5-3.5; the organic matter content of the oil cake organic fertilizer exceeds 70%, and the total nitrogen, phosphorus and potassium content exceeds 7.0%; the organic matter content of the earthworm castings organic fertilizer is 25%-38%, the nitrogen content is 2.5%, the phosphorus content is 1.9%, and the potassium content is 2.1%.

[0039] In some embodiments, the application amount of the organic-inorganic compound fertilizer is 150-200 kg / mu.

[0040] In some embodiments, the dosage of the low-temperature growth-promoting bacteria agent is 1.8 L / thousand strains to 2.2 L / thousand strains, preferably 1.9 L / thousand strains to 2.1 L / thousand strains, for example 2 L / thousand strains.

[0041] In some embodiments, the low-temperature growth-promoting bacteria is a nicotinovoran Arthrobacter agent composed of nicotinovoran Arthrobacter, wall Bacillus, selenomonas and Bacillus amyloliquefaciens, the nicotinovoran Arthrobacter is Arthrobacternicotinovorans 112, with a preservation number of CGMCC No. 16516, the wall Bacillus is Bacillus muralis114, with a preservation number of CGMCC No. 16517, the selenomonas is Pseudomonas seleniipraecipitans TD1, with a preservation number of CGMCC No. 16518, and the amyloliquefaciens is Bacillus amyloliquefaciens Ba-S, with a preservation number of CGMCC No. 8262.

[0042] In some embodiments, the preparation method of the low-temperature growth-promoting bacterial agent includes: inoculating four strains of bacteria into a beef extract peptone liquid culture medium, shaking and culturing at 170 rpm and 30°C for 24 hours, and then inoculating them into a beef extract peptone liquid culture medium at a 5% inoculation rate, shaking and culturing at 170 rpm and 30°C for 48 hours; centrifuging the culture solution at a speed of 6000×g for 10 minutes, collecting the bacterial bodies and resuspending them with the same volume of sterilized deionized water to obtain the bacterial bodies, and uniformly mixing the bacterial bodies of the four bacterial strains at a volume ratio of 1:1:1:1 to obtain the low-temperature growth-promoting bacterial agent, whose concentration is about 10 8 CFU / g.

[0043] The present invention also relates to a flue-cured tobacco prepared by the flue-cured tobacco production method described in any embodiment of the present invention.

[0044] In some embodiments, the content of Maillard browning reaction products in flue-cured tobacco is greater than or equal to 6 μg / g, the content of aromatic amino acid degradation products is greater than or equal to 7 μg / g, the content of ceprechan-like degradation products is greater than or equal to 88 μg / g, and the content of fatty acids is greater than or equal to 42 μg / g.

[0045] In some embodiments, the total sugar content of the flue-cured tobacco is greater than or equal to 16%, and the reducing sugar content is greater than or equal to 23%.

[0046] Beneficial Effects of the Invention

[0047] The flue-cured tobacco production method provided by the present invention adopts a special organic-inorganic compound fertilizer as a base fertilizer, and sprays a low-temperature growth-promoting bacterial agent on the leaf surface of the tobacco seedlings during the seedling stage, especially on the day of transplanting, so as to promote the growth and development of the root system of the flue-cured tobacco, thereby resisting low temperature, promoting root colonization, promoting nutrient absorption and utilization of the flue-cured tobacco under low temperature conditions, and improving the accumulation of key nutrient elements such as nitrogen, phosphorus and potassium during the dome period of the flue-cured tobacco.

[0048] The flue-cured tobacco production method provided by the present invention can obtain field fresh tobacco leaves that are softer, have more tobacco oil, better ripening resistance, better baking characteristics, and significantly reduce the proportion of diseased leaves.

[0049] The method of the present invention can significantly improve the grade of tobacco leaves, thereby increasing the economic value of the tobacco leaves.

[0050] The flue-cured tobacco leaves obtained by the flue-cured tobacco production method provided by the invention have high contents of total sugar and reducing sugar, high ratio of two sugars and better coordination.

[0051] The flue-cured tobacco leaves obtained by the flue-cured tobacco production method provided by the present invention have high content of aroma components, for example, Maillard browning reaction products, aromatic amino acid degradation products, cedarwood degradation products, and fatty acids have high content.

[0052] The flue-cured tobacco leaves obtained by the flue-cured tobacco production method provided by the present invention have high sensory quality scores, and in particular, the scores of aroma quality, aroma quantity, taste, miscellaneous smell and irritation are significantly higher than those of flue-cured tobacco leaves produced by conventional production methods.

[0053] The flue-cured tobacco production method provided by the present invention can significantly reduce diseases of initially flue-cured tobacco leaves, improve the coordination of the main chemical components of tobacco leaves, increase the content of aroma substances and enhance the sensory quality of tobacco leaves.

[0054] The flue-cured tobacco production method provided by the present invention is significantly superior to conventional production methods, and can effectively solve a series of key problems in tobacco leaf production caused by early planting of tobacco plants, such as delayed seedling recovery, nutrient deficiency, and reduced quality. DETAILED DESCRIPTION

[0055] The substantive content of the present invention is further described below in conjunction with specific embodiments of the present invention. It should be understood that the following examples are only used to illustrate the present invention, but are not intended to limit the scope of protection of the present invention. In the following examples, if specific conditions are not specified, they are carried out according to conventional conditions or manufacturer recommendations. The raw materials used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0056] Although many materials, operating methods and detection methods used in the following examples are well known in the art, the present invention is still described in as much detail as possible. It is clear to those skilled in the art that the materials and operating methods used in the following examples are well known in the art unless otherwise specified.

[0057] The commercial organic fertilizer used in the embodiment of the present invention is provided by the Tobacco Farmers' Cooperative of Wuchuan County, Guizhou Province, and has the following nutrient contents: organic matter 23%, nitrogen 0.45%, phosphorus 0.2%, and potassium 0.65%.

[0058] The base fertilizer used in the embodiment of the present invention was purchased from Guizhou Ketai Jinfu Agricultural Development Co., Ltd., and the formula was N:P2O5:K2O=10:10:25.

[0059] The special organic-inorganic compound fertilizer used in the embodiment of the present invention is prepared by mixing water-soluble fertilizer, oil cake organic fertilizer and earthworm casting organic fertilizer according to the mass ratio of 1:2.5:2.5, and then manufactured by extrusion granulation. Wherein the water-soluble fertilizer is a solid fertilizer that can be dissolved in water, purchased from Ketai Jinfu Agricultural Development Co., Ltd., mainly including nitrogen, phosphorus, potassium and micronutrient elements such as boron and copper, wherein nitrogen (in terms of N), phosphorus (in terms of P2O5), and potassium (in terms of K2O) content ratio is 1:1:2.5~3.5. Oil cake organic fertilizer is prepared by the method disclosed in CN101475408A, and its organic matter content exceeds 70%, and the total nitrogen, phosphorus and potassium content exceeds 7.0%. Earthworm casting organic fertilizer is purchased from Guizhou Jilong Ecological Technology Co., Ltd., and its organic matter content can reach 25%~38%, nitrogen content 2.5%, phosphorus content 1.9%, and potassium content 2.1%.

[0060] The preparation method of the low-temperature growth-promoting bacterial agent used in the embodiment of the present invention is as follows: the purified four strains of bacteria are inoculated into beef extract peptone liquid culture medium respectively, and cultured at 170rpm and 30°C for 24h, and then inoculated into beef extract peptone liquid culture medium at an inoculation rate of 5%, and cultured at 170rpm and 30°C for 48h; the fermentation broth is centrifuged at a speed of 6000×g for 10min, and the bacterial bodies are collected and resuspended with the same volume of sterilized deionized water to obtain the bacterial bodies, and the bacterial bodies of the four bacterial strains are uniformly mixed at a volume ratio of 1:1:1:1 to obtain a low-temperature growth-promoting bacterial agent, and the concentration thereof is about 10 8CFU / g. The four strains are: Arthrobacter nicotinovorans 112, with a preservation number of CGMCC No.16516; Bacillus muralis 114, with a preservation number of CGMCC No.16517; Pseudomonas seleniipraecipitans TD1, with a preservation number of CGMCC No.16518; Bacillus amyloliquefaciens Ba-S, with a preservation number of CGMCC No.8262. The formula of beef extract peptone medium is: beef extract 5.0g, sodium chloride 5.0g, peptone 10g, agar 20g, distilled water 1000mL, pH 7.0-7.2, sterilized at 121℃ for 20min, used for bacterial culture.

[0061] In the embodiments of the present invention, the root activity is detected by referring to the method disclosed in "Zhu Xiuyun, Liang Meng, Ma Yu. Experimental review report on the determination of root activity (TTC method) [J]. Guangdong Chemical Industry, 2020, 47(6): 2."

[0062] In the embodiment of the present invention, the method for determining the root system architecture is as follows: complete root systems of three representative tobacco plants were collected from each experimental group, the roots were rinsed clean, and then the roots were scanned using an Epson Expression 10000XL root scanner, and the root length, root surface area, average root diameter and root volume were calculated using winRHIZO software.

[0063] In the embodiments of the present invention, agronomic traits are investigated with reference to the "Investigation and Measurement Standards for Tobacco Agronomic Traits" (YC / T 142-2010).

[0064] In the examples of the present invention, the economic traits were investigated according to the method of GB 2635-1992, the flue-cured tobacco leaves of each test group were graded, and the yield and output value of the tobacco leaves of each plot were calculated.

[0065] In the embodiments of the present invention, the key element nutrient accumulation determination is carried out with reference to "Soil Agrochemical Analysis".

[0066] In the embodiment of the present invention, the chemical composition and sensory evaluation determination method is as follows: the sample is divided into two parts along the main vein of the tobacco leaf, and the main vein is removed. One half is used to determine the content of main chemical components such as nicotine, total sugar, reducing sugar, total potassium, total nitrogen, chlorine, etc., and the total score of the coordination evaluation of the main chemical components of tobacco leaves in each experimental group is calculated; the other half is rolled into single-material cigarettes, and relevant experts are organized to conduct sensory quality evaluation based on YC / T138-1998, and the evaluation indicators include aroma quality (10 points), aroma quantity (10 points), taste (12 points), miscellaneous smell (10 points), and irritation (10 points).

[0067] In an embodiment of the present invention, the content of aroma components in tobacco leaves after curing, such as Maillard browning reaction products, aromatic amino acid degradation products, cypermethrin-like degradation products, and fatty acids, is determined by using a 7890B / 5977B gas chromatograph-mass spectrometer (Agilent Technologies, CA, USA) using a simultaneous distillation extraction (SDE) combined with a gas chromatography-mass spectrometry (GC-MS) method to determine the aroma substances in tobacco leaves, and the obtained spectrum is retrieved and qualitatively identified by a computer spectrum library NIST14, and the relative content of the aroma substances in tobacco leaves is calculated by an internal standard method. Chromatographic conditions: HP5MS (30m×0.25mm×0.25μm) capillary column; carrier gas helium, flow rate 1.0mL / min; injection port temperature 260℃; injection volume 1μL, split injection, split ratio 20:1; program temperature rise: initial temperature 50℃, hold for 1min; increase from 50℃ to 160℃ at a rate of 8℃ / min, hold for 2min; then increase from 160℃ to 280℃ at a rate of 8℃ / min, hold for 15min, total running time 45min. Mass spectrometry conditions: solvent delay 3min; ionization voltage 70eV; ion source temperature 230℃; transfer line temperature 280℃; ion scanning range: 35~450amu; mass spectrometry scanning mode: SCAN.

[0068] The experiment was conducted in Maotian Town, Wuchuan County, Guizhou Province from 2021 to 2022. The test soil was a representative tobacco-growing yellow soil with uniform fertility in the local area, and two test groups, a control group and a treatment group, were set up on it. The test area of ​​each test group was the same and they were distributed in the test field according to random block arrangements. Among them, the control group applied base fertilizer and chemical fertilizer first according to local fertilization habits, with 50kg / mu of strip application, and then applied commercial organic fertilizer, with 100kg / mu of strip application; the treatment group used special organic-inorganic compound fertilizer, with 150kg / mu of strip application. The test flue-cured tobacco variety was Yunyan 87, about 1,000 plants / mu. The tobacco seedlings in the control group were sprayed with clean water on the day of transplanting, with a dosage of 2L / mu, and the tobacco seedlings in the treatment group were sprayed with low-temperature growth-promoting bacteria on the day of transplanting, with a dosage of 2L / mu.

[0069] After the flue-cured tobacco enters the maturity stage, the 15th to 16th leaf position of the upper leaves are used as test materials. The test tobacco leaves are cultivated and managed in accordance with the standardized production of local high-quality tobacco leaves, and are harvested and cured according to the tobacco leaf maturity standards and baking process. The test curing room is a standard intensive curing room with rising airflow. The harvested fresh tobacco leaves are loaded into the standard intensive curing room and baked according to the three-stage baking process. Comparative tests are carried out to evaluate and analyze the tobacco leaves produced by the method of the present invention (treatment) and the conventional production method (control) from the aspects of seedling quality, nutritional status and economic traits, chemical composition and sugar coordination, aroma quality and sensory quality.

[0070] The control group was harvested and baked according to the local conventional production technology, and the treatment group was harvested and baked according to the harvesting and baking method of the present invention.

[0071] The harvesting and baking method of the present invention comprises:

[0072] S3, early harvesting of fresh tobacco leaves: harvesting 5-7 days earlier than conventional harvesting, tobacco leaves obviously fade green, hairs fall off, main and branch veins turn white, and more than 90% of tobacco leaves reach a suitable maturity;

[0073] S4, classification and arrangement of fresh tobacco leaves: fresh tobacco leaves are roughly divided into three categories: unripe, mature and overripe, and then arranged into poles. Each pole has 130 to 150 leaves.

[0074] S5, loading: Classify and layer tobacco, load the same layer with the same quality, unripe tobacco in the low temperature layer, overripe tobacco in the high temperature layer, and other layers with ripe tobacco. The loading volume is 15% to 25% higher than the normal level.

[0075] S6, baking: shorten the baking time of the yellowing stage by 6 to 10 hours, extend the baking time of the color fixing stage by 8 to 12 hours, increase the main yellowing temperature of tobacco leaves by 1°C to 2°C, increase the wet bulb temperature of the yellowing and color fixing stages by 0.5°C to 1°C, and follow normal operations for other operations. The specific operations are as follows:

[0076] S 6-1 After ignition, the dry bulb temperature is raised to 34.5℃ at a heating rate of 1℃ / h, and the wet bulb temperature is 34℃. The tobacco leaves in the high temperature layer are baked at a steady temperature for 2 hours until they turn 10% to 20% yellow.

[0077] S 6-2 , raise the dry bulb temperature to 36℃ and the wet bulb temperature to 35.5℃ at a heating rate of 1℃ / h, and bake at a steady temperature for 3 hours until the tobacco leaves in the high temperature layer turn 20% to 30% yellow and become slightly soft;

[0078] S 6-3 , raise the dry bulb temperature to 39°C at a rate of 1°C / h, stabilize the wet bulb temperature at 37-38°C, start the circulating fan at low speed, and bake at a steady temperature for 15-20 hours until the high-temperature layer tobacco leaves turn 70% to 80% yellow and become soft;

[0079] S 6-4 , raise the dry bulb temperature to 41°C at a rate of 1°C / 2h, and the wet bulb temperature to 37-38°C, and bake at a steady temperature for 10-15h, until the tobacco leaves turn 80% to 90% yellow and the main veins become slightly soft;

[0080] S 6-5 , raise the dry bulb temperature to 43℃ at a rate of 1℃ / 3h, stabilize the wet bulb temperature at 37.5℃, and bake at a steady temperature for 8-12h until the high temperature layer tobacco leaves turn yellow, curl at the tip, and dry more than 1 / 4 of the leaves;

[0081] S 6-6 , raise the dry bulb temperature to 46℃ and the wet bulb temperature to 37.5℃ at a rate of 1℃ / 2~3h, and bake at a steady temperature for 8~12h until most of the main ribs of the high temperature layer tobacco leaves turn yellow and more than 1 / 3 of the leaves are dry;

[0082] S 6-7 , raise the dry bulb temperature to 48℃ and the wet bulb temperature to 38.5℃ at a rate of 1℃ / 2~3h, and bake at a steady temperature for 8~12h until the main tendons of the high-temperature layer tobacco turn yellow, the leaves are more than 1 / 2 dry, and are in a small roll state;

[0083] S 6-8 , raise the dry bulb temperature to 51℃ and the wet bulb temperature to 39℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 3-5h until the high temperature layer of tobacco leaves is more than 2 / 3 dry, and the main tendons of the tobacco leaves on the whole kang turn yellow and shrink significantly;

[0084] S 6-9 , raise the dry bulb temperature to 53℃ and the wet bulb temperature to 39.5℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 12 to 18h until the whole tobacco leaves are dry and rolled into large rolls, and the main tendons of the high-temperature layer are dried by more than 1 / 3;

[0085] S 6-10 , raise the dry bulb temperature to 60℃ and the wet bulb temperature to 40℃ at a heating rate of 1℃ / h, and bake at a steady temperature for 4-5h until the main tendons of the high-temperature layer tobacco leaves are more than 1 / 2 dry;

[0086] S 6-11 , raise the dry-bulb temperature to 68°C and the wet-bulb temperature to 41°C at a heating rate of 1°C / h, and bake at a steady temperature for 20 to 25 hours until the tobacco leaves on the kang are completely dry.

[0087] The test results are as follows.

[0088] 1. Quality of flue-cured tobacco seedlings

[0089] Seven days after transplanting, the effects of different treatments on root activity and root architecture of flue-cured tobacco were investigated. The results are shown in Table 1.

[0090] Table 1 Effects of different treatments on root activity and root architecture of flue-cured tobacco

[0091]

[0092] Note: Different lowercase letters after the numbers indicate significant differences at the 5% level, p<0.05; the same lowercase letters after the numbers indicate no significant differences.

[0093] The results showed that the root length, root surface area, average root diameter and root volume of the treatment group were greater than those of the control group, and the TTC reduction intensity of the treatment group was also significantly higher than that of the control group, indicating that the root vitality of the treatment group was significantly higher than that of the control group. The above test results show that the use of special organic-inorganic compound fertilizer as base fertilizer and the spraying of low-temperature growth-promoting bacteria on the leaves of tobacco seedlings during the seedling stage, especially on the day of transplanting, can promote the growth and development of the flue-cured tobacco root system, thereby resisting low temperatures, promoting root colonization, and promoting the absorption and utilization of nutrients of flue-cured tobacco under low temperature conditions.

[0094] 2. Nutritional status of flue-cured tobacco

[0095] (1) Seven days after topping, the flue-cured tobacco entered the dome stage. The effects of different treatments on the agronomic traits and accumulation of key nutrient elements of flue-cured tobacco were investigated. The results are shown in Table 2. There were no significant differences in the agronomic traits of the flue-cured tobacco in the treatment group at the dome stage compared with the control group.

[0096] Table 2 Effects of different treatments on agronomic traits of flue-cured tobacco at dome stage

[0097]

[0098] Note: Different lowercase letters after the numbers indicate significant differences at the 5% level, p<0.05; the same lowercase letters after the numbers indicate no significant differences.

[0099] (2) The effects of different treatments on agronomic traits and accumulation of key nutrients in the dome stage of flue-cured tobacco were investigated, and the results are shown in Table 3. The results showed that the accumulation of key nutrients in the dome stage of flue-cured tobacco in the treatment group, such as nitrogen, phosphorus and potassium, was significantly greater than that in the control group.

[0100] Table 3 Effects of different treatments on the accumulation of key nutrient elements in flue-cured tobacco during the dome stage

[0101]

[0102] Note: Different lowercase letters after the numbers indicate significant differences at the 5% level, p<0.05; the same lowercase letters after the numbers indicate no significant differences.

[0103] The above test results show that using special organic-inorganic compound fertilizer as base fertilizer and spraying low-temperature growth-promoting bacteria on the leaves of tobacco seedlings during the seedling stage, especially on the day of transplanting, can promote the absorption and utilization of nutrients in flue-cured tobacco under low temperature conditions and increase the accumulation of key nutrient elements such as nitrogen, phosphorus and potassium during the dome period of flue-cured tobacco.

[0104] 3. Diseases and quality of first-cured tobacco leaves

[0105] (1) The effects of different treatments on the quality and ripening resistance of field fresh tobacco leaves and the incidence of diseased leaves were investigated. The results are shown in Table 4. The results showed that compared with the control group, the field fresh tobacco leaves in the treatment group were softer, had more tobacco oil, better ripening resistance, better baking characteristics, and the incidence of diseased leaves was significantly reduced.

[0106] Table 4 Effects of different treatments on the quality and maturity resistance of fresh tobacco leaves and the incidence of diseased leaves in the field

[0107]

[0108] Note: Maturity and yellowing time refers to the time interval from the last mature harvest of the middle leaves; different lowercase letters after the numbers indicate significant differences at the 5% level, p<0.05; the same lowercase letters after the numbers indicate no significant differences.

[0109] (2) The effects of different treatments on the grade structure and economic traits of flue-cured tobacco leaves were investigated, and the results are shown in Table 5. The results show that the proportion of orange-yellow tobacco leaves and the proportion of upper-middle tobacco leaves in the flue-cured tobacco leaves of the treatment group were significantly higher than those of the control group, and the average price of tobacco leaves was also higher than that of the control group. This indicates that the method of the present invention can significantly improve the grade of tobacco leaves, thereby improving the economic value of tobacco leaves.

[0110] Table 5 Effects of different treatments on grade and economic traits of flue-cured tobacco leaves

[0111]

[0112] Note: Different lowercase letters after the numbers indicate significant differences at the 5% level, p<0.05; the same lowercase letters after the numbers indicate no significant differences.

[0113] (3) The effects of different treatments on the chemical composition of flue-cured tobacco leaves were investigated, and the results are shown in Table 6. The results showed that the total sugar, reducing sugar content, and two-sugar ratio of the flue-cured tobacco leaves in the treatment group were higher than those in the control group, and the coordination of the treatment group was better than that of the control group; while the nicotine, starch, and protein contents were significantly lower than those in the control group.

[0114] Table 6 Effects of different treatments on the chemical composition content and harmony of flue-cured tobacco leaves

[0115]

[0116] Note: The ratio of reducing sugar to total sugar is more harmonious when it is greater than 0.9; different lowercase letters after the numbers indicate significant differences at the 5% level, p<0.05; the same lowercase letters after the numbers indicate no significant differences.

[0117] (4) The effects of different treatments on the aroma content of flue-cured tobacco leaves were investigated, and the results are shown in Table 7. The results showed that the aroma component contents of flue-cured tobacco leaves in the treatment group, such as Maillard browning reaction products, aromatic amino acid degradation products, cypermethrin-like degradation products, and fatty acids, were higher than those in the control group.

[0118] Table 7 Effects of different treatments on the aroma components of flue-cured tobacco leaves (μg / g)

[0119]

[0120] Note: Different lowercase letters after the numbers indicate significant differences at the 5% level, p<0.05; the same lowercase letters after the numbers indicate no significant differences.

[0121] (5) The effects of different treatments on the sensory quality of flue-cured tobacco leaves were investigated, and the results are shown in Table 8. The results showed that the sensory quality scores of the flue-cured tobacco leaves in the treatment group, especially the scores of aroma quality, aroma quantity, taste, miscellaneous smell and irritation, were higher than those in the control group.

[0122] Table 8 Effects of different treatments on sensory quality of flue-cured tobacco leaves

[0123]

[0124] Note: Sensory quality evaluation is the sum of the scores of aroma quality, aroma quantity, taste, offal, irritation and strength, each of which is 10 points, with a total score of 60 points. Different lowercase letters after the numbers indicate significant differences at the 5% level, p<0.05; the same lowercase letters after the numbers indicate no significant differences.

[0125] The method of this invention adopts a specially prepared organic-inorganic compound fertilizer as a base fertilizer, and during the seedling stage, especially on the day of transplanting, the leaf surface of the tobacco seedlings is sprayed with a low-temperature growth-promoting bacterial agent, and then through a matching tobacco leaf harvesting and baking process, it can significantly reduce the diseases of the first-baked tobacco leaves, improve the coordination of the main chemical components of the tobacco leaves, increase the content of aroma substances and improve the sensory quality of the tobacco leaves.

[0126] The above test results show that the method of the present invention is significantly superior to conventional production methods and can effectively solve a series of key problems in tobacco leaf production caused by early planting of tobacco plants, such as slow seedling recovery, nutrient deficiency, and reduced quality.

[0127] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A flue-cured tobacco production method, comprising: S1: Before transplanting flue-cured tobacco, an organic-inorganic compound fertilizer is applied into the soil by strip application or hole application, wherein the organic-inorganic compound fertilizer is composed of water-soluble fertilizer, oil cake organic fertilizer, and earthworm castings organic fertilizer, wherein the mass ratio of the water-soluble fertilizer, the oil cake organic fertilizer, and the earthworm castings organic fertilizer is 1:2.4-2.6:1.6-2.6; S2: When the average daily field temperature is below 15°C, transplant tobacco seedlings and spray the leaves with low-temperature growth-promoting bacteria.

2. The flue-cured tobacco production method according to claim 1, further comprising: S3: Fresh tobacco leaves are harvested 5-7 days earlier than the conventional harvest. At this time, the leaves are obviously chlorotic, the hairs fall off, the main and branch veins turn white, and more than 90% of the leaves reach a suitable maturity; S4: Fresh tobacco leaves are roughly divided into three categories: unripe, mature and overripe, and then sorted into poles, with 130 to 150 leaves per pole; S5: The same layer and the same quality are loaded on the kang, unripe tobacco leaves are loaded on the low temperature layer, overripe tobacco leaves are loaded on the high temperature layer, and other layers are loaded with moderately ripe tobacco leaves. The loading volume is 15% to 25% higher than the conventional one. S6: Baking. Compared with the conventional baking process, the main yellowing temperature of tobacco leaves is increased by 1℃~2℃, the wet bulb temperature during the yellowing and color fixing periods is increased by 0.5℃~1℃, the baking time during the yellowing period is shortened by 6~10h, and the baking time during the color fixing period is extended by 8~12h.

3. The flue-cured tobacco production method according to claim 2, wherein S6 comprises: S 6-1 After ignition, the dry bulb temperature is raised to 34.5°C at a heating rate of 1°C / h, and the wet bulb temperature is 34°C. The tobacco leaves in the high temperature layer are baked at a steady temperature until they turn 10% to 20% yellow. S 6-2 , raise the dry bulb temperature to 36℃ and the wet bulb temperature to 35.5℃ at a heating rate of 1℃ / h, and bake at a steady temperature until the high temperature layer tobacco leaves turn 20% to 30% yellow and slightly soften; S 6-3 , raise the dry bulb temperature to 39°C at a heating rate of 1°C / h, stabilize the wet bulb temperature at 37-38°C (e.g. 37.5°C), start the circulating fan at a low gear, and bake at a steady temperature until the high-temperature layer tobacco leaves turn 70% to 80% yellow and the leaves become soft; S 6-4 , raise the dry-bulb temperature to 41°C at a rate of 1°C / 2h, and the wet-bulb temperature to 37-38°C (e.g. 37.5°C), and bake at a steady temperature until the tobacco leaves turn 80% to 90% yellow and the main veins become slightly soft; S 6-5 , raise the dry bulb temperature to 43℃ at a heating rate of 1℃ / 3h, stabilize the wet bulb temperature at 37.5℃, and bake at a steady temperature until the high-temperature layer tobacco leaves are fully yellowed, the tips are curled, and the leaves are more than 1 / 4 dry; S 6-6 , raise the dry bulb temperature to 46℃ and the wet bulb temperature to 37.5℃ at a heating rate of 1℃ / 2~3h, and bake at a steady temperature until most of the main ribs of the high-temperature layer tobacco leaves turn yellow and more than 1 / 3 of the leaves are dry; S 6-7 , raise the dry bulb temperature to 48℃ and the wet bulb temperature to 38.5℃ at a heating rate of 1℃ / 2~3h, and bake at a steady temperature until the main tendons of the high-temperature layer tobacco leaves turn yellow, the leaves are more than 1 / 2 dry, and are in a small roll state; S 6-8 , raise the dry bulb temperature to 51℃ and the wet bulb temperature to 39℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature until the high-temperature layer tobacco leaves are more than 2 / 3 dry, and the main tendons of the tobacco leaves on the whole kang turn yellow and shrink significantly; S 6-9 , raise the dry bulb temperature to 53℃ and the wet bulb temperature to 39.5℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature until the whole tobacco leaves are dry and rolled into large rolls, and the main tendons of the high-temperature layer are dried by more than 1 / 3; S 6-10 , raise the dry bulb temperature to 60℃ and the wet bulb temperature to 40℃ at a heating rate of 1℃ / h, and bake at a steady temperature until the main tendons of the high-temperature layer tobacco leaves are more than 1 / 2 dry; S 6-11 , raise the dry bulb temperature to 68℃ and the wet bulb temperature to 41℃ at a heating rate of 1℃ / h, and bake at a steady temperature until the tobacco leaves on the kang are completely dry.

4. The flue-cured tobacco production method according to claim 3, wherein S6 comprises: S 6-1 After ignition, the dry bulb temperature is raised to 34.5℃ at a heating rate of 1℃ / h, and the wet bulb temperature is 34℃. The tobacco leaves in the high temperature layer are baked at a steady temperature for 2 hours until they turn 10% to 20% yellow. S 6-2 , raise the dry bulb temperature to 36℃ and the wet bulb temperature to 35.5℃ at a heating rate of 1℃ / h, and bake at a steady temperature for 3 hours until the tobacco leaves in the high temperature layer turn 20% to 30% yellow and become slightly soft; S 6-3 , raise the dry bulb temperature to 39°C at a rate of 1°C / h, stabilize the wet bulb temperature at 37-38°C (e.g. 37.5°C), start the circulating fan at low speed, and bake at a steady temperature for 15-20h, until the high-temperature layer tobacco leaves turn 70% to 80% yellow and become soft; S 6-4 , raise the dry-bulb temperature to 41°C at a rate of 1°C / 2h, and the wet-bulb temperature to 37-38°C (e.g. 37.5°C), and bake at a steady temperature for 10-15h until the tobacco leaves turn 80% to 90% yellow and the main veins become slightly soft; S 6-5 , raise the dry bulb temperature to 43℃ at a rate of 1℃ / 3h, stabilize the wet bulb temperature at 37.5℃, and bake at a steady temperature for 8-12h until the high temperature layer tobacco leaves turn yellow, curl at the tip, and dry more than 1 / 4 of the leaves; S 6-6 , raise the dry bulb temperature to 46℃ and the wet bulb temperature to 37.5℃ at a rate of 1℃ / 2~3h, and bake at a steady temperature for 8~12h until most of the main ribs of the high temperature layer tobacco leaves turn yellow and more than 1 / 3 of the leaves are dry; S 6-7 , raise the dry bulb temperature to 48℃ and the wet bulb temperature to 38.5℃ at a rate of 1℃ / 2~3h, and bake at a steady temperature for 8~12h until the main tendons of the high-temperature layer tobacco turn yellow, the leaves are more than 1 / 2 dry, and are in a small roll state; S 6-8 , raise the dry bulb temperature to 51℃ and the wet bulb temperature to 39℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 3-5h, until the high temperature layer of tobacco leaves is more than 2 / 3 dry, and the main tendons of the tobacco leaves on the whole kang turn yellow and shrink significantly; S 6-9 , raise the dry bulb temperature to 53℃ and the wet bulb temperature to 39.5℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 12 to 18h until the whole tobacco leaves are dry and rolled into large rolls, and the main tendons of the high-temperature layer are dried by more than 1 / 3; S 6-10 , raise the dry bulb temperature to 60℃ and the wet bulb temperature to 40℃ at a heating rate of 1℃ / h, and bake at a steady temperature for 4-5h until the main tendons of the high-temperature layer tobacco leaves are more than 1 / 2 dry; S 6-11 , raise the dry-bulb temperature to 68°C and the wet-bulb temperature to 41°C at a heating rate of 1°C / h, and bake at a steady temperature for 20 to 25 hours until the tobacco leaves on the kang are completely dry.

5. The flue-cured tobacco production method according to any one of claims 1 to 4, wherein the mass ratio of the water-soluble fertilizer, the oil cake organic fertilizer, and the earthworm castings organic fertilizer is 1:2.4-2.6:2-2.6, for example, 1:2.5:2.

5.

6. The flue-cured tobacco production method according to any one of claims 1 to 5, wherein the mass content ratio of nitrogen calculated as N, phosphorus calculated as P2O5, and potassium calculated as K2O in the water-soluble fertilizer is 1:1:2.5-3.5; the organic matter content of the oil cake organic fertilizer exceeds 70%, and the total nitrogen, phosphorus and potassium content exceeds 7.0%; the organic matter content of the earthworm castings organic fertilizer is 25%-38%, the nitrogen content is 2.5%, the phosphorus content is 1.9%, and the potassium content is 2.1%.

7. The flue-cured tobacco production method according to any one of claims 1 to 6, wherein the application amount of the organic-inorganic compound fertilizer is 150-200 kg / mu.

8. The flue-cured tobacco production method according to any one of claims 1 to 7, wherein the dosage of the low-temperature growth-promoting bacteria agent is 1.8 L / 1000 plants to 2.2 L / 1000 plants, preferably 1.9 L / 1000 plants to 2.1 L / 1000 plants, for example 2 L / 1000 plants.

9. The flue-cured tobacco production method according to any one of claims 1 to 8, wherein the low-temperature growth-promoting bacteria agent is a nicotinovoran Arthrobacter agent composed of nicotinovoran Arthrobacter, wall-bacillus, selenomonas and Bacillus amyloliquefaciens, the nicotinovoran Arthrobacter is Arthrobacter nicotinovorans 112, with a preservation number of CGMCC No. 16516, the wall-bacillus is Bacillus muralis 114, with a preservation number of CGMCC No. 16517, the selenomonas is Pseudomonasseleniipraecipitans TD1, with a preservation number of CGMCC No. 16518, and the amyloliquefaciens is Bacillusamyloliquefaciens Ba-S, with a preservation number of CGMCC No. 8262.

10. The flue-cured tobacco production method according to claim 9, wherein the preparation method of the low-temperature growth-promoting bacterial agent comprises: The four strains were inoculated in beef extract peptone liquid culture medium, shaken and cultured at 170 rpm and 30°C for 24 h, and then inoculated in beef extract peptone liquid culture medium at an inoculation rate of 5%, shaken and cultured at 170 rpm and 30°C for 48 h; the culture solution was centrifuged at 6000×g for 10 min, the bacterial bodies were collected and resuspended with the same volume of sterilized deionized water to obtain the bacterial bodies, and the bacterial bodies of the four strains were uniformly mixed at a volume ratio of 1:1:1:1 to obtain the low-temperature growth-promoting bacterial agent, whose concentration was about 10 8 CFU / g.

11. A flue-cured tobacco prepared by the flue-cured tobacco production method according to any one of claims 1 to 10, Preferably, the content of the Maillard browning reaction product of the flue-cured tobacco is greater than or equal to 6 μg / g, the content of the aromatic amino acid degradation product is greater than or equal to 7 μg / g, the content of the ceprechan-like degradation product is greater than or equal to 88 μg / g, and the content of the fatty acid substance is greater than or equal to 42 μg / g; Preferably, the total sugar content of the flue-cured tobacco is greater than or equal to 16%, and the reducing sugar content is greater than or equal to 23%.

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