Cultivation and baking method for improving oil content of baked tobacco leaves

Abstract

The invention discloses a cultivation and baking method for improving the oil content of baked tobacco leaves, and relates to the technical field of tobacco leaf planting and baking, the method comprises the following steps: in the whole growth period of tobacco plants, applying tea oil in a segmented manner according to 4-6 kg / mu: applying 20-30% of the tea oil in 30-35 days after the tobacco plants are transplanted; 40%-50% of the total amount of the tea oil is irrigated 45-50 days after transplanting; 60-65 days after transplanting, the remaining tea oil is applied; the harvested tobacco leaves fertilized with the tea oil are subjected to three-stage baking, wherein the tobacco leaves are subjected to slow heating in a yellowing stage, a color fixing stage and a stem drying stage and are subjected to segmented moisturizing baking, and the whole stems of the tobacco leaves are dried. A precise time regulation and control system based on the whole growth period of the tobacco leaves is established, a cultivation-baking coordinated regulation and control mechanism is constructed, baking process parameters are optimized, the oil content of the baked tobacco leaves is remarkably and stably improved, and the method has the multiple advantages of improving quality, saving cost and the like and is suitable for high-end tobacco leaf raw material production.

Description

Technical Field

[0001] This invention relates to the field of tobacco planting and curing technology, and in particular to a cultivation and curing method for increasing the oil content of cured tobacco leaves. Background Technology

[0002] In the high-end cigarette industry, the oil content of cured tobacco leaves is one of the decisive indicators for measuring their sensory quality and core value. Sufficient oil content not only imparts a richer, more mellow aroma and a more delicate and comfortable taste to the smoke, but also significantly reduces irritation, making it an indispensable characteristic of high-grade tobacco raw materials. For a long time, tobacco production has suffered from insufficient oil content and unstable quality in cured tobacco leaves. Traditional cultivation methods rely excessively on chemical fertilizers, which, while ensuring yield, easily lead to soil compaction and acidification, and microbial imbalance, thereby inhibiting the efficiency of nutrient absorption by the tobacco plant roots and severely affecting the synthesis and accumulation of oil precursors such as lipids and waxes in the tobacco leaves. To improve this situation, the industry has attempted to introduce organic fertilizers such as rapeseed cake fertilizer or plant oils such as rapeseed oil. These substances can provide organic matter and trace elements, optimizing the soil microenvironment to a certain extent and indirectly increasing oil content. However, existing technologies have significant limitations, restricting their application effectiveness: The timing of application lacks precision. Existing methods mostly involve a one-time application during the rosette stage of tobacco plants, failing to differentiate the supply based on the dynamic needs of lipid absorption and metabolism at different growth stages. This can lead to insufficient or excessive nutrient supply during critical periods of oil synthesis, resulting in unstable oil enhancement effects, with increases varying by 20%-30% between different plots. Furthermore, the selection and utilization of oilseed types are inadequate. Current research and practice focus heavily on common oils such as rapeseed oil, while paying little attention to specialty oils rich in high proportions of unsaturated fatty acids such as oleic acid and fat-soluble vitamins such as vitamin E and phytosterols, such as tea oil. These specialty components theoretically can more efficiently promote the formation of the waxy layer and lipid accumulation in tobacco leaves, but systematic research on their application for enhancing tobacco oil content is currently lacking. Finally, cultivation measures are disconnected from curing processes. Existing technologies only focus on oilseed application in the field, failing to optimize it in conjunction with the subsequent curing process. Baking is a crucial step in determining whether oil content can be effectively preserved. Traditional baking processes, such as high-temperature rapid color setting, easily lead to the oxidation, decomposition, and volatilization of oil substances synthesized in the field, preventing them from being retained to the maximum extent in the cured tobacco leaves, thus negating the benefits of previous cultivation efforts. Therefore, to address these issues, developing a technical solution based on tea oil-integrated, precise, and time-series control, combined with a complementary baking process, is of great significance for steadily improving the oil content of cured tobacco leaves and overcoming the bottleneck in high-end tobacco quality. Summary of the Invention

[0003] In view of the above-mentioned defects or deficiencies in the prior art, the present invention provides a cultivation and curing method for improving the oil content of cured tobacco leaves, establishing a precise time control system based on the entire growth period of tobacco leaves, constructing a cultivation-curing synergistic control mechanism, optimizing curing process parameters, and achieving a significant and stable increase in the oil content of cured tobacco leaves, thus providing technical support for the production of high-quality tobacco leaves.

[0004] This invention provides a cultivation and curing method for increasing the oil content of tobacco leaves after curing, comprising: Apply tea oil in stages throughout the tobacco plant's growth period, totaling 4-6 kg / mu: The first application is 30-35 days after transplanting, mixing 20%-30% of the total tea oil with 500 times its volume of water, and applying it in a circular trench 10-12 cm deep, 15 cm away from the base of the stem, followed by covering with soil; the second application is 45-50 days after transplanting, applying 40%-50% of the total tea oil directly to the roots, and immediately supplementing with 1.5 kg / mu of water afterward; the third application is 60-65 days after transplanting, applying the remaining tea oil directly to the roots, and immediately supplementing with 1.5 kg / mu of water afterward. The harvested tobacco leaves treated with tea oil are subjected to a three-stage curing process: during the yellowing stage, the curing temperature is increased from 31-32℃ to 41-42℃, while maintaining a relative humidity of 75%-80%, and the leaves are cured for 72 hours; during the color-fixing stage, the curing temperature is increased from 41-42℃ to 54-55℃, with the temperature maintained at 50℃ for 12 hours, and the humidity is gradually reduced from 75%-80% to 50% at a rate of 10% decrease for every 5℃ increase, and the leaves are cured at 54-55℃ for 10-14 hours; during the rib-drying stage, the curing temperature is increased from 54-55℃ to 67-68℃, and the leaves are cured at 67-68℃ for 20-24 hours until the tobacco leaves are completely dry and the humidity is controlled below 30%.

[0005] Furthermore, apply 50-60 kg / mu of chemical compound fertilizer 7 days before transplanting, apply 15-20 kg / mu of the same chemical compound fertilizer 20-25 days after transplanting, and apply 10-15 kg / mu of potassium sulfate 40-45 days after transplanting.

[0006] Furthermore, the chemical compound fertilizer has the following composition: N-P2O5-K2O=10-12-18.

[0007] Furthermore, this also includes measuring soil pH and soil organic matter content before transplanting.

[0008] Furthermore, it also includes soil compatibility adjustment based on the measured soil pH value, specifically including: When the soil pH value is <5.5, when applying tea oil for the first time, apply 50-60 kg / mu of quicklime simultaneously to adjust the soil pH value to 5.8-6.2; When the soil pH value is between 5.5 and 6.5, the tea oil should be mixed with 0.3-0.5 kg / mu of magnesium sulfate and applied during the first irrigation. When the soil pH value is >6.5, 7 days before transplanting tobacco plants, evenly spread 50-60 kg of decomposed sawdust or peat moss per acre and plow it into the soil to a depth of 15-20 cm to adjust the soil pH value to 6.0-6.5.

[0009] Furthermore, it also includes soil suitability adjustment based on the measured soil organic matter content, specifically including: When the soil organic matter content is less than 15 g / kg of soil, apply 50 kg / mu of well-rotted rapeseed cake fertilizer in conjunction with the first application of tea oil. When the soil organic matter content is less than 25 g / kg and less than 15 g / kg, the tea oil should be mixed with 20 kg / mu of well-rotted sheep manure and applied in furrows during the first irrigation. When the soil organic matter content is greater than 25 g / kg of soil, apply 20-30 kg / mu of river sand with a particle size of 0.5-2 mm 10 days before transplanting tobacco plants, and mix the river sand with the soil at a mass ratio of 1:5.

[0010] Furthermore, the baking temperature is adjusted at a heating rate of 0.5℃ / h during the yellowing period.

[0011] Furthermore, the baking temperature is adjusted at a heating rate of 1℃ / h during the color-fixing period.

[0012] Furthermore, the baking temperature is adjusted at a heating rate of 2℃ / h during the drying period.

[0013] This invention provides a cultivation and curing method for increasing the oil content of tobacco leaves after curing. Specifically designed for oil content enhancement, it directly promotes the synthesis of the waxy layer and oil precursors in tobacco leaves through the targeted supply of lipids such as unsaturated fatty acids and phytosterols from tea oil, resulting in a more precise oil content enhancement effect. This invention employs a three-stage tea oil irrigation approach: 20%–30% of the total amount applied during the early vegetative growth stage, 40%–50% during the vigorous growth stage, and 20%–30% before maturity. This precisely matches the oil metabolism needs of tobacco plants at different growth stages, compared to existing technologies. Applying rapeseed oil at a single time can increase the oil accumulation efficiency by 30% to 40% and promote the increase of the wax layer thickness of tobacco leaves by 20% to 30%. Combining tea oil application with an oil-retaining roasting process with optimized process parameters of "slow heating + segmented moisturizing" reduces the oxidation loss of oil substances during roasting, and the oil retention rate is more than 20% higher than that of the rapeseed oil solution. By applying tea oil in a targeted and precise time sequence and matching it with roasting, a significant and stable increase in the oil content of the roasted tobacco leaves is achieved. It has multiple advantages such as quality improvement and cost reduction, and is suitable for the production of high-end tobacco raw materials. Attached Figure Description

[0014] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic flowchart of a cultivation and curing method for improving the oil content of tobacco leaves after curing, provided in one embodiment of this application. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0016] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0017] It should be understood that although the terms first, second, third, etc., may be used to describe the acquisition modules in the embodiments of the present invention, these acquisition modules should not be limited to these terms. These terms are only used to distinguish the acquisition modules from each other.

[0018] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0019] It should be noted that the directional terms such as "upper," "lower," "left," and "right" used in the embodiments of the present invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of the present invention. Furthermore, in the context, it should be understood that when it is mentioned that an element is formed "upper" or "lower" of another element, it can not only be formed directly "upper" or "lower" of the other element, but also indirectly "upper" or "lower" of the other element through an intermediate element.

[0020] This invention provides a cultivation and curing method for increasing the oil content of tobacco leaves after curing, comprising: Step S101: Apply tea oil in stages throughout the tobacco plant's growth period, totaling 4-6 kg / mu (mu ≈ 666.7 square meters): The first application of tea oil is carried out 30-35 days after transplanting. Mix 20%-30% of the total tea oil with 500 times its volume of water and apply it in a circular trench 15 cm away from the stem base, with a trench depth of 10-12 cm. Cover with soil after application. The second application of tea oil is carried out 45-50 days after transplanting. Apply 40%-50% of the total tea oil directly to the roots and immediately supplement with 1.5 kg / mu of water after application. The third application of tea oil is carried out 60-65 days after transplanting. Apply the remaining tea oil directly to the roots and immediately supplement with 1.5 kg / mu of water after application. Specifically, firstly, apply base fertilizer. Seven days before transplanting tobacco plants, apply 50-60 kg / mu of chemical compound fertilizer. This chemical compound fertilizer has the formula N-P2O5-K2O=10-12-18, meaning that the content of nitrogen (N), phosphorus pentoxide (P2O5), and potassium oxide (K2O) in this chemical compound fertilizer is 10%, 12%, and 18%, respectively. Secondly, apply topdressing. 20-25 days after transplanting, that is, before the seedling stage, apply 15-20 kg / mu of the above-mentioned chemical compound fertilizer. 40-45 days after transplanting, that is, at the beginning of the vigorous growth stage, apply 10-15 kg / mu of potassium sulfate. In addition, soil pH and soil organic matter content were measured before tobacco plants were transplanted in order to adjust soil suitability.

[0021] In addition to applying chemical compound fertilizer, apply tea oil in stages throughout the tobacco plant's growth period, totaling 4-6 kg / mu. Preferably, apply 5 kg / mu of tea oil throughout the tobacco plant's growth period, divided into 3 applications, with the amount of each application allocated according to the growth stage. The first application of tea oil should be carried out 30-35 days after the tobacco plants are transplanted, which is the early stage of vegetative growth. Mix 20% to 30% of the total amount of tea oil with 500 times the volume of water and apply it in a circular trench 15cm away from the base of the stem, with a trench depth of 10 to 12cm. Cover with soil after application. Preferably, the first application uses 30% of the total amount of tea oil, which is 1.5kg / mu (5kg / mu). At this stage, the tea oil application provides the lipid nutrition basis for the development of the tobacco plant roots and promotes the early activation of enzymes related to oil synthesis, such as acyltransferase. The second application of tea oil should be carried out 45-50 days after the tobacco plants are transplanted, during the vigorous growth period. This stage is also the critical period for oil synthesis. Apply 40% to 50% of the total amount of tea oil directly to the roots. Immediately after application, add 1.5 kg / mu of clean water to promote root absorption. Preferably, the second application uses 50% of the total amount of tea oil (5 kg / mu), i.e., 2.5 kg / mu. Increasing the amount of tea oil applied directly to the roots at this stage significantly enhances the accumulation of fatty acids, waxes and other substances in the leaves. The third application of tea oil should be carried out 60-65 days after the tobacco plants are transplanted, that is, before the maturity period. This stage is also the period of oil accumulation. The remaining tea oil is directly applied to the roots. Immediately after application, 1.5 kg / mu of clean water is added to promote root absorption and enhance the accumulation of wax on the surface of the leaves. Preferably, the third application of tea oil uses the remaining 1 kg / mu of the total tea oil application of 5 kg / mu. This stage specifically enhances the adhesion of oil on the surface of the middle and upper leaves, solving the problem of insufficient oil accumulation in the later stage.

[0022] In addition, soil compatibility was adjusted based on the measured soil pH and soil organic matter content. Specifically, adjusting the soil pH included: When the soil pH value is <5.5, when applying tea oil for the first time, apply 50-60 kg / mu of quicklime simultaneously to adjust the soil pH value to 5.8-6.2, so as to avoid the degradation of lipids in tea oil due to excessive soil acidity. When the soil pH is between 5.5 and 6.5, it is the suitable range for tobacco plant growth and tea oil absorption. There is no need to apply quicklime to adjust the soil pH. However, when applying tea oil for the first time, tea oil should be mixed with 0.3-0.5 kg / mu of magnesium sulfate for irrigation to promote the synergistic synthesis of lipids and chlorophyll in tea oil and avoid the inhibition of the synthesis of oil precursors such as carotenoids due to magnesium deficiency. When the soil pH value is >6.5, 7 days before transplanting tobacco plants, evenly spread 50-60 kg / mu of well-rotted sawdust or peat moss and plow it into the soil to a depth of 15-20 cm to adjust the soil pH value to 6.0-6.5. Alkaline soil will cause the fatty acids in tea oil to undergo saponification reaction to form insoluble fatty acid salts, which will reduce the root absorption efficiency. The organic acids in well-rotted sawdust or peat moss can slowly reduce the soil pH value.

[0023] Adjusting soil organic matter content specifically includes: When the soil organic matter content is less than 15 g / kg of soil, apply 50 kg / mu of well-rotted rapeseed cake fertilizer during the first application of tea oil to enhance the soil's fertilizer retention capacity and promote the slow release of tea oil. When the soil organic matter content is less than 25 g / kg and less than 15 g / kg, no additional organic fertilizer is needed. However, when applying tea oil for the first time, tea oil should be mixed with 20 kg / mu of pre-crushed and sieved decomposed sheep manure and then applied in furrows. The small molecule organic acids in the sheep manure can promote the emulsification of tea oil and improve the root system's absorption efficiency of lipids. When the soil organic matter content is greater than 25 g / kg of soil, apply 20-30 kg / mu of river sand with a particle size of 0.5-2 mm 10 days before transplanting tobacco plants. Mix the river sand with the soil at a mass ratio of 1:5. The river sand can improve soil porosity, prevent harmful substances such as hydrogen sulfide produced by the decomposition of tea oil from inhibiting root activity, and ensure the continuous absorption of oil substances.

[0024] Step S102 involves a three-stage baking process for the harvested tobacco leaves treated with tea oil: During the yellowing stage, the baking temperature is increased from 31-32℃ to 41-42℃, maintaining a relative humidity of 75%-80%, and baking for 72 hours; during the color-fixing stage, the baking temperature is increased from 41-42℃ to 54-55℃, with the temperature maintained at 50℃ for 12 hours, and the humidity gradually reduced from 75%-80% to 50% at a rate of 10% decrease for every 5℃ increase, baking at 54-55℃ for 10-14 hours; during the rib-drying stage, the baking temperature is increased from 54-55℃ to 67-68℃, baking at 67-68℃ for 20-24 hours, until the tobacco leaves are completely dry and the humidity is controlled below 30%.

[0025] Specifically, after harvesting tobacco leaves treated with tea oil, an oil-preserving curing process is carried out, employing a three-stage curing parameter control method: The yellowing period, also known as the stabilization period of oil precursors, involves adjusting the baking temperature from 31-32℃ to 41-42℃ at a heating rate of 0.5℃ / h, maintaining a relative humidity of 75%-80%, and baking for 72 hours, which is 12 hours longer than the traditional process. This ensures that the yellowing degree of the tobacco leaves reaches more than 80% and avoids premature decomposition of lipids due to high temperatures. The color-fixing period, also known as the oil curing period, involves adjusting the baking temperature from 41-42℃ to 54-55℃ at a heating rate of 1℃ / h. The temperature is maintained at 50℃ for 12 hours. The humidity is gradually reduced from 75%-80% to 50% at a rate of 10% decrease for every 5℃ increase. The tobacco leaves are then baked at 54-55℃ for 10-14 hours, preferably at 55℃ for 12 hours, to ensure that the tobacco leaves are dry until the main veins soften, thus reducing excessive oil loss with moisture. The drying period, also known as the oil stabilization period, involves adjusting the baking temperature from 54-55℃ to 67-68℃ at a rate of 2℃ / h, and baking at 67-68℃ for 20-24 hours until the tobacco leaves are completely dry. The humidity is controlled below 30%. Preferably, baking at 68℃ for 22 hours until the tobacco leaves are completely dry is carried out. Temperatures should be avoided from exceeding 70℃ to prevent the oil from oxidizing due to high temperatures.

[0026] This invention was demonstrated in a control experiment conducted in a tobacco-growing area of ​​Luoping County, Qujing City, Yunnan Province, at an altitude of 1750m. The tobacco variety used was K326. The specific method is as follows: Set up a control group (conventional cultivation + traditional baking): Conventional cultivation steps: Seven days before transplanting, apply 55 kg / mu of chemical compound fertilizer, wherein the chemical compound fertilizer is N-P2O5-K2O=10-12-18; Apply 18 kg / mu of chemical compound fertilizer 20 days after transplanting, and 12 kg / mu of potassium sulfate 40 days after transplanting. No further fertilization is required thereafter. Other field management follows conventional agricultural operations, including tilling, weeding, and pruning, without the application of oilseeds, soil compatibility adjustment, or synergistic application of trace elements.

[0027] Traditional baking steps: During the yellowing period, the baking temperature is increased from 32℃ to 42℃ at a rate of 1℃ / h, with a relative humidity of 70%, for 60 hours. When 80% of the leaves turn yellow, the next stage begins. During the color-fixing period, the baking temperature was increased from 42℃ to 55℃ at a heating rate of 1℃ / h, and the relative humidity was suddenly reduced from 70% to 40% for 24 hours, with the goal of rapid color fixing and preventing dust accumulation. During the drying stage, the baking temperature is increased from 55℃ to 70℃ at a rate of 1℃ / h and maintained for 14 hours to rapidly dry the tobacco sticks at high temperature.

[0028] Set up treatment group 1 (rapeseed oil irrigation + traditional baking): Based on conventional cultivation procedures, 7.5 kg / mu of rapeseed oil was applied to the roots of tobacco plants 35 days after transplanting. The harvested tobacco leaves treated with rapeseed oil were then cured using traditional curing methods.

[0029] Set up treatment group 2 (segmented application of tea oil + oil-retaining baking): Tea oil application steps in stages: Based on conventional cultivation procedures, apply 5 kg / mu of tea oil in three applications throughout the entire growth period of the tobacco plants: The first application of tea oil was carried out 30 days after the tobacco plants were transplanted. 30% of the total tea oil application, i.e., 1.5 kg / mu, was mixed with 500 times the volume of water and applied in a circular trench 11 cm deep, 15 cm away from the base of the stem. After application, the soil was covered with soil. The soil pH was measured to be around 5. At the same time, 55 kg / mu of quicklime was applied to adjust the soil pH to 5.8-6.2. The soil organic matter content was measured to be around 10 g / kg of soil. 50 kg / mu of well-rotted rapeseed cake fertilizer was also applied in conjunction with the application. The second application of tea oil was carried out 45 days after the tobacco plants were transplanted. 50% of the total amount of tea oil, i.e., 2.5 kg / mu, was applied directly to the roots, and 1.5 kg / mu of clean water was added immediately after the application. The third application of tea oil was carried out 60 days after the tobacco plants were transplanted. The remaining tea oil, i.e., 1 kg / mu, was applied directly to the roots, and 1.5 kg / mu of clean water was added immediately after the application.

[0030] Oil-retaining baking steps: During the yellowing period, the baking temperature is increased from 32℃ to 42℃ at a rate of 0.5℃ / h, while maintaining a relative humidity of 75%~80% for 72 hours to ensure that the yellowing degree of the tobacco leaves reaches more than 80%. During the color-fixing period, the baking temperature was increased from 42℃ to 55℃ at a rate of 1℃ / h. The temperature was maintained at 50℃ for 12 hours. The humidity was gradually reduced from 75%~80% to 50% at a rate of 10% decrease for every 5℃ increase. The tobacco leaves were baked at 55℃ for 12 hours to ensure that the main veins of the tobacco leaves were dry. During the drying stage, the baking temperature is increased from 55℃ to 68℃ at a rate of 2℃ / h, and the tobacco leaves are baked at 68℃ for 22 hours until the entire tobacco leaf is dry, with the humidity controlled below 30%.

[0031] The experimental results are shown in Tables 1 and 2. In this embodiment, the oil content grade of the upper and middle tobacco leaves in treatment group 2 was "high," which was more stable than that in treatment group 1, verifying the significant effect of this embodiment on improving oil content. The proportion of high-quality tobacco leaves in treatment group 2 increased by 2.78 percentage points compared to treatment group 1 and by 9.67 percentage points compared to the control group. The total amount of neutral aroma substances in the flue-cured tobacco leaves of treatment group 2 increased by 15.23% compared to treatment group 1, of which the proportion of cephalosporin-like substances related to oil content reached 47.88%, which is consistent with the aroma substance characteristics of high-quality tobacco leaves. The aroma quantity and oiliness of the sensory evaluation of treatment group 2 were significantly improved compared to the control group and treatment group 1, and the irritation score was significantly improved, i.e., the irritation was significantly reduced, verifying the synergistic effect of oil content improvement on sensory evaluation quality. The above results indicate that this embodiment is superior to the existing technology in terms of oil stability, tobacco quality, and sensory evaluation performance, and the dosage is lower than the optimal dosage of rapeseed oil, combining the advantages of quality improvement and cost reduction.

[0032] Table 1 Comparison of Oil Grades and Quality Indicators Table 2 Comparison of Sensory Evaluation Performance This embodiment provides a cultivation and curing method for increasing the oil content of tobacco leaves after curing. Specifically designed for oil content enhancement, it directly promotes the synthesis of the waxy layer and oil precursors in tobacco leaves through the targeted supply of lipids such as unsaturated fatty acids and phytosterols from tea oil, resulting in a more precise oil content increase. This invention employs a three-stage tea oil irrigation approach: 20%–30% of the total amount applied during the early vegetative growth stage, 40%–50% during the vigorous growth stage, and 20%–30% before maturity. This precisely matches the oil metabolism needs of tobacco plants at different growth stages, compared to existing technologies. Applying rapeseed oil at a single time can increase the oil accumulation efficiency by 30% to 40% and promote the increase of the wax layer thickness of tobacco leaves by 20% to 30%. Combining tea oil application with an oil-retaining baking process with optimized process parameters of "slow heating + segmented moisturizing" reduces the oxidation loss of oil substances during baking, and the oil retention rate is more than 20% higher than that of the rapeseed oil solution. By applying tea oil in a targeted manner and adapting it to baking, a significant and stable increase in the oil content of tobacco leaves after baking is achieved. It has multiple advantages such as quality improvement, cost saving and environmental protection, and is suitable for the production of high-end tobacco raw materials.

[0033] The above description is merely a preferred embodiment of the present invention. Those skilled in the art should understand that the scope of disclosure in this invention is not limited to the specific combination of the above-described technical features, but should also cover other technical solutions formed by any combination of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this invention.

Claims

1. A cultivation and curing method for increasing the oil content of tobacco leaves after curing, characterized in that, include: Apply tea oil in stages throughout the tobacco plant's growth period, totaling 4-6 kg / mu: The first application is 30-35 days after transplanting, mixing 20%-30% of the total tea oil with 500 times its volume of water, and applying it in a circular trench 10-12 cm deep, 15 cm away from the base of the stem, followed by covering with soil; the second application is 45-50 days after transplanting, applying 40%-50% of the total tea oil directly to the roots, and immediately supplementing with 1.5 kg / mu of water afterward; the third application is 60-65 days after transplanting, applying the remaining tea oil directly to the roots, and immediately supplementing with 1.5 kg / mu of water afterward. The harvested tobacco leaves treated with tea oil are subjected to a three-stage curing process: during the yellowing stage, the curing temperature is increased from 31-32℃ to 41-42℃, while maintaining a relative humidity of 75%-80%, and the leaves are cured for 72 hours; during the color-fixing stage, the curing temperature is increased from 41-42℃ to 54-55℃, with the temperature maintained at 50℃ for 12 hours, and the humidity is gradually reduced from 75%-80% to 50% at a rate of 10% decrease for every 5℃ increase, and the leaves are cured at 54-55℃ for 10-14 hours; during the rib-drying stage, the curing temperature is increased from 54-55℃ to 67-68℃, and the leaves are cured at 67-68℃ for 20-24 hours until the tobacco leaves are completely dry and the humidity is controlled below 30%.

2. The cultivation and curing method for increasing the oil content of flue-cured tobacco leaves according to claim 1, characterized in that, Also includes: Seven days before transplanting tobacco plants, apply 50-60 kg / mu of chemical compound fertilizer. 20-25 days after transplanting, apply 15-20 kg / mu of the same chemical compound fertilizer. 40-45 days after transplanting, apply 10-15 kg / mu of potassium sulfate.

3. The cultivation and curing method for increasing the oil content of flue-cured tobacco leaves according to claim 2, characterized in that, The chemical compound fertilizer is N-P2O5-K2O=10-12-18.

4. The cultivation and curing method for increasing the oil content of cured tobacco leaves according to claim 3, characterized in that, It also includes measuring soil pH and soil organic matter content before transplanting.

5. The cultivation and curing method for increasing the oil content of cured tobacco leaves according to claim 4, characterized in that, It also includes soil compatibility adjustment based on measured soil pH values, specifically including: When the soil pH value is <5.5, when applying tea oil for the first time, apply 50-60 kg / mu of quicklime simultaneously to adjust the soil pH value to 5.8-6.2; When the soil pH value is between 5.5 and 6.5, the tea oil should be mixed with 0.3-0.5 kg / mu of magnesium sulfate during the first application of tea oil. When the soil pH value is >6.5, 7 days before transplanting tobacco plants, evenly spread 50-60 kg of decomposed sawdust or peat moss per acre and plow it into the soil to a depth of 15-20 cm to adjust the soil pH value to 6.0-6.

5.

6. The cultivation and curing method for increasing the oil content of flue-cured tobacco leaves according to claim 5, characterized in that, It also includes soil suitability adjustment based on the measured soil organic matter content, specifically including: When the soil organic matter content is less than 15 g / kg of soil, apply 50 kg / mu of well-rotted rapeseed cake fertilizer in conjunction with the first application of tea oil. When the soil organic matter content is less than 25 g / kg and less than 15 g / kg, the tea oil should be mixed with 20 kg / mu of well-rotted sheep manure and applied in furrows during the first irrigation. When the soil organic matter content is greater than 25 g / kg of soil, apply 20-30 kg / mu of river sand with a particle size of 0.5-2 mm 10 days before transplanting tobacco plants, and mix the river sand with the soil at a mass ratio of 1:

5.

7. The cultivation and curing method for increasing the oil content of flue-cured tobacco leaves according to claim 1, characterized in that, The baking temperature is adjusted at a heating rate of 0.5℃ / h during the yellowing period.

8. The cultivation and curing method for increasing the oil content of flue-cured tobacco leaves according to claim 1, characterized in that, The color-fixing period involves adjusting the baking temperature at a heating rate of 1℃ / h.

9. The cultivation and curing method for increasing the oil content of cured tobacco leaves according to claim 1, characterized in that, The baking temperature during the drying period is adjusted at a heating rate of 2℃ / h.

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