A method for topping yunyan 87 suitable for low latitude and high altitude tobacco growing areas

Abstract

This invention discloses a method for topping Yunyan 87 tobacco variety suitable for low-latitude, high-altitude tobacco-growing areas. The method involves transplanting tobacco plants between April 25th and May 5th, and then classifying and topping the plants according to their growth status (early flowering, poor growth, average growth, good growth, and excellent growth). Specifically, for early flowering plants, the "flowering without leaf removal" method is used, lengthening the internode distance by 5 cm and leaving 16 leaves, with the plant height controlled at 80-85 cm after topping. For plants with poor, average, good, and excellent growth, 18, 20, 22, and 24 leaves are left respectively, with plant heights controlled at 90-95 cm, 100-105 cm, 110-115 cm, and 120-125 cm. Experiments have shown that this method significantly improves tobacco yield and economic benefits, with a substantial increase in per-acre output value and the proportion of high-quality tobacco, superior to traditional topping methods. This method effectively solves the problems of unreasonable plant population structure and low tobacco yield and quality in low-latitude, high-altitude tobacco-growing areas.

Description

Technical Field

[0001] This invention relates to a method for topping Yunyan 87 tobacco, applicable to low-latitude, high-altitude tobacco-growing areas, and belongs to the field of flue-cured tobacco planting technology. Background Technology

[0002] In flue-cured tobacco cultivation, a reasonable plant structure is crucial for improving tobacco yield and quality. As a core raw material for high-quality cigarettes, optimizing the cultivation and management techniques of Yunyan 87 plays a key role in enhancing the appearance and sensory quality of the tobacco leaves. Shuicheng District, belonging to Liupanshui City, is located in western Guizhou Province, at a high altitude, and belongs to the mid-subtropical monsoon climate zone. The region's climate is characterized by large temperature differences, uneven rainfall distribution, and a long frost-free period. However, due to its high altitude and significant vertical climate variations, the growing environment for tobacco leaves is complex and variable.

[0003] In current cultivation practices of Yunyan 87 tobacco, transplanting time is typically controlled between April 25th and May 5th. Fertilization is categorized into two types based on soil fertility: medium fertility and slightly above-medium fertility, with basal fertilizer and organic fertilizer applied respectively. However, existing topping methods mainly include pinching back the growing tip, topping at bud break, topping at the beginning of flowering, and topping at full bloom. While these methods can produce good plant growth and appearance in years with normal climates, they often have limitations when facing the complex climatic conditions and soil environments of low-latitude, high-altitude tobacco-growing areas.

[0004] Specifically, the Yunyan 87 tobacco fields in low-latitude, high-altitude tobacco-growing areas often face the problem of an unreasonable plant population structure. This manifests as either excessive nutrient intake leading to overly vigorous growth or malnutrition resulting in poor leaf development. This unreasonable population structure easily leads to the formation of umbrella-shaped and cone-shaped tobacco plants, which in turn affects the thickness, chemical composition, and sensory quality of the tobacco leaves, reducing the overall quality and market competitiveness of the tobacco. Furthermore, existing topping methods, if improper fertilization management or climatic factors occur during the secondary growth period after topping, can easily lead to further imbalances in plant morphology, increasing the difficulty of cultivation management.

[0005] Therefore, there is an urgent need to develop a new topping method for Yunyan 87 tobacco suitable for low-latitude, high-altitude tobacco-growing areas. This method should effectively improve the individual and group structure of tobacco plants, promote normal leaf development, enhance the appearance and internal quality of tobacco leaves, and increase yield and economic benefits. This has significant practical importance and application value for solving the current bottlenecks restricting the sustainable development of low-latitude, high-altitude tobacco-growing areas and promoting the steady development of the flue-cured tobacco industry. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for topping Yunyan 87 in low-latitude, high-altitude tobacco-growing areas, so as to overcome the shortcomings of the prior art.

[0007] The technical solution of this invention is: a method for topping Yunyan 87 tobacco in low-latitude, high-altitude tobacco-growing areas, the method being:

[0008] Transplanting was completed between April 25 and May 5;

[0009] The tobacco plants were divided into five categories: early flowering, poor growth, average growth, relatively good growth, and good growth. Appropriate topping treatments were applied based on their different growth conditions. The specific methods are as follows:

[0010] 1) The method for early flowering and topping is to top when the internode lengthens to 5 cm and the number of leaves is 16. Then top the plant and leave 3-5 cm of stem above the top leaves. The plant height after topping is 80-85 cm.

[0011] 2) The method for pruning the plant with poor growth is to prune it when the internode lengthens to 5 cm and the number of leaves is 18. After pruning, leave 3-5 cm of stem above the top leaves. The plant height after pruning is 90-95 cm.

[0012] 3) The method of topping when the plant is growing well is to top when the internode lengthens to 5 cm and the number of leaves is 20. After topping, leave 3-5 cm of stem above the top leaves. The plant height after topping is 100-105 cm.

[0013] 4) The method for pruning plants with good growth is to prune them when the internode length is 5 cm and the number of leaves is 22. After pruning, leave 3-5 cm of stem above the top leaves. The plant height after pruning is 110-115 cm.

[0014] 5) The method for topping when the plant is growing well is to top when the internode length is 5 cm and the number of leaves is 24. After topping, leave 3-5 cm of stem above the top leaves. The plant height after topping should be 120-125 cm.

[0015] Furthermore, the method of removing the flowers but not the leaves is adopted when pruning the early-flowering plants.

[0016] Furthermore, the fertilization requirements for the method are as follows:

[0017] Medium-fertility tobacco fields: Apply 60 to 65 kg of base fertilizer per mu;

[0018] For tobacco fields with medium to high fertility: apply 50 to 55 kg of base fertilizer per mu;

[0019] Organic fertilizer application: ≥70 kg / mu of commercial organic fertilizer, or 300 kg to 500 kg / mu of farmyard manure;

[0020] Potassium fertilizer: Apply 10 to 15 kg per mu;

[0021] Superphosphate: Apply 20 kg per acre;

[0022] Special top dressing: Apply 18 kg per mu;

[0023] Seedling fertilizer: Apply 2.5 kg per mu.

[0024] The beneficial effects of this invention are: compared with the prior art,

[0025] 1) The topping method for Yunyan 87 of this invention classifies and tops the tobacco plants according to their different growth stages (early flowering, poor growth, average growth, good growth, and excellent growth), scientifically adjusting the number of leaves retained and plant height. Combined with reasonable fertilization management, this effectively improves the plant structure, promoting the formation of excellent cylindrical tobacco plants and increasing the number of effective leaves. This method significantly improves the appearance, chemical composition, and sensory quality of tobacco leaves, ensuring bright color, sufficient oil content, and a loose yet elastic tissue structure. Simultaneously, experimental results show that the yield and economic benefits of tobacco plants using this topping method are significantly higher than those of traditional topping methods, with a substantial increase in per-acre output value and the proportion of high-grade tobacco, fully demonstrating its significant economic benefits. This method is highly adaptable, especially suitable for low-latitude, high-altitude tobacco-growing areas with complex and variable climates. It effectively addresses plant structure imbalances caused by over- or under-nutrition, reducing the difficulty of cultivation management and promoting uniform leaf development and high-quality production. Therefore, the jointing and topping method of the present invention not only solves the problems of unreasonable group structure and low tobacco yield and quality in the prior art, but also provides strong technical support for the sustainable development of the flue-cured tobacco industry, and has broad application prospects and promotion value;

[0026] 2) This invention employs a "flower removal without leaf removal" method during early flowering and topping, significantly optimizing the growth management of Yunyan 87 tobacco plants. By removing only flower buds while retaining leaves, it effectively delays the premature entry of tobacco plants into the reproductive growth stage, avoiding insufficient leaf quantity and quality decline caused by early flowering. It also promotes the rational distribution of nutrients, ensuring full leaf expansion and normal development. This method prevents the formation of conical tobacco plants, maintains the cylindrical structure of the plant, and improves leaf uniformity and thickness, thereby enhancing the appearance quality and chemical composition of the tobacco leaves. Furthermore, retaining more leaves helps enhance the photosynthetic capacity of the tobacco plant, increasing the total sugar content and nicotine level of the leaves, further improving sensory quality and economic value. In conclusion, the "flower removal without leaf removal" method for early flowering and topping not only effectively improves the individual and group structure of tobacco plants, enhances the quality and yield of tobacco leaves, but also significantly increases the economic benefits per acre. It provides strong technical support for the sustainable development of Yunyan 87 in low-latitude, high-altitude tobacco-growing areas, and has broad application prospects and promotional value.

[0027] 3) The fertilization requirements of this invention involve scientifically and rationally configuring the amount of base fertilizer and organic fertilizer for tobacco fields with different fertility levels, ensuring that Yunyan 87 tobacco plants receive sufficient and balanced nutrition under different soil conditions. For tobacco fields with medium fertility, apply 60 to 65 kg of base fertilizer per mu (approximately 0.067 hectares), while for tobacco fields with medium to high fertility, apply 50 to 55 kg of base fertilizer per mu (approximately 0.067 hectares), avoiding the problem of nutrient excess or deficiency and promoting healthy growth of tobacco plants. Use ≥70 kg / mu of commercial organic fertilizer or 300 to 500 kg / mu of farmyard manure to effectively improve soil structure, enhance soil fertility and water and fertilizer retention capacity, and promote root development and soil microbial activity. Apply 10 to 15 kg / mu of potassium fertilizer to improve the disease resistance and leaf quality of tobacco plants; apply 20 kg / mu of superphosphate to help strengthen the cell wall of leaves, improving leaf elasticity and durability. Apply 18 kg / mu of special topdressing fertilizer and 2.5 kg / mu of seedling fertilizer to ensure rapid recovery and continuous growth of tobacco plants after topping, promoting full leaf expansion and uniform development. The comprehensive fertilization program optimized nutrient distribution in Yunyan 87 tobacco, preventing plant shape imbalances and leaf quality decline caused by improper fertilization. It significantly improved the appearance, chemical composition, and sensory quality of the tobacco leaves, thereby increasing yield and economic benefits. This scientific fertilization management method has strong adaptability and promotional value, effectively supporting the sustainable cultivation of Yunyan 87 in low-latitude, high-altitude tobacco-growing areas and promoting the steady development of the flue-cured tobacco industry. Detailed Implementation

[0028] Example 1:

[0029] The current topping methods are topping at the beginning of the bud, at the first flowering stage, and at the peak of flowering. However, these topping methods can lead to conical tobacco plants and conical tobacco plants with large or small leaves after topping, if the fertilization is not reasonable or the climate is affected.

[0030] The first method: Early flowering and topping. Climate: 1. In low-latitude, high-altitude tobacco-growing areas, if the minimum temperature in May is below 13℃ for more than 15 days after transplanting, early flowering occurs during the tobacco growing season, especially in the early stages. Temperatures below 13℃ promote premature plant development, easily leading to early flowering and reducing tobacco yield and quality. 2. In May and June after transplanting, high temperatures, low rainfall, increased evaporation, and reduced soil moisture lead to insufficient water supply to the tobacco plants, inhibiting growth. The plants are shorter than normal, and the number of leaves does not reach the required level for the variety before entering reproductive growth, resulting in early flowering and reducing tobacco yield and quality. For early flowering caused by these two climate conditions: Use the method of topping without removing leaves, at the jointing stage. When the internode lengthens to 5cm and the number of leaves reaches 16, then top the plant, leaving 3-5cm of stem above the top leaves. After topping, the plant height should be 80-85cm.

[0031] The second method: Topping tobacco plants with poor growth: When the internode lengthens to 5cm and the number of leaves is 18, topping is carried out. After topping, 3-5cm of stem is left on the top leaves. The plant height after topping is 90-95cm.

[0032] The third method: Topping tobacco plants with average growth: When the internode lengthens to 5cm and the number of leaves is 20, topping is carried out. After topping, 3-5cm of stem is left on the top leaves. The plant height after topping is 100-105cm.

[0033] The fourth method: Topping of tobacco plants with good growth: When the internode lengthens to 5cm and the number of leaves is 22, topping is carried out. After topping, 3-5cm of stem is left on the top leaves. The plant height after topping is 110-115cm.

[0034] The fifth method: Topping healthy tobacco plants: When the internode lengthens to 5cm and the number of leaves is 24, topping is carried out. After topping, 3-5cm of stem is left on the top leaves. The plant height after topping is 120-125cm.

[0035] Transplanting requirements. In tobacco-growing areas at higher altitudes, transplanting should be completed between April 25 and May 5. The transplanting period within the same area should be controlled within 5 days, and the transplanting period for each tobacco farmer should be controlled within 3 days.

[0036] Fertilization requirements: For tobacco fields with medium fertility, apply 60-65 kg / mu of base fertilizer per mu; for tobacco fields with medium to high fertility, apply 50-55 kg / mu of base fertilizer per mu, ≥70 kg / mu of commercial organic fertilizer or 300-500 kg / mu of farmyard manure. Also apply 10-15 kg / mu of potassium fertilizer, 20 kg / mu of superphosphate, 18 kg / mu of special topdressing fertilizer, and 2.5 kg / mu of seedling fertilizer.

[0037] Experiment 1:

[0038] Early flowering and topping were implemented, with one control and three treatments, each consisting of 1200 tobacco plants. In the control, flower buds were removed along with the leaves above the buds, and the plant was topped using standard production methods. In treatment 1, flower buds and the two leaves below the bud were removed, and the plant was topped. In treatment 2, flower buds and the three leaves below the bud were removed, and the plant was topped. In treatment 3, when the internode length increased to 5cm and the number of leaves reached 16, topping was performed, leaving 3-5cm of stem above the top leaves. The plant height after topping was 80-85cm. Agronomical traits were measured one day before curing. After curing, the appearance quality of the tobacco leaves and the smoking quality (X2F, C3F, B2F) were measured, along with the percentage of high-quality tobacco, average price, and average yield per acre.

[0039] Table 1. Agronomic traits of tobacco leaves under each treatment

[0040]

[0041] Treatment 3 produces a cylindrical plant shape with 16 leaves, resulting in high-quality tobacco leaves.

[0042] Treatment 3 significantly increased plant height (81.3 cm) and the number of effective leaves (14 leaves), forming cylindrical tobacco plants, which was superior to the conical shape of the control group and the umbrella shape of treatments 1 and 2.

[0043] The control group and treatments 1 and 2 had lower plant height and less than ideal plant shape.

[0044] Table 2 Evaluation of the appearance quality of tobacco leaves under each treatment

[0045]

[0046] The tobacco leaves of treatment 3 were orange-yellow in color, had a bright luster, sufficient oil content, loose texture, and good elasticity, which was superior to the other treatment groups.

[0047] Table 3 Chemical composition of tobacco leaves under different treatments

[0048]

[0049] Treatment 3 showed that the total sugar, reducing sugar, total nitrogen, nicotine, potassium chloride, and sugar / alkali ratio were all within the standard range in the lower, middle, and upper parts of the sample. The control group and treatments 1 and 2 showed that some indicators were lower and higher.

[0050] Table 4 Sensory quality evaluation of tobacco leaves under each treatment

[0051]

[0052] Treatment 3 scored the highest in terms of aroma quality, aroma quantity, and off-odors (74.5 points), which was significantly better than the control group (67.5 points) and treatments 1 and 2.

[0053] Table 5 Economic traits of tobacco leaves under each treatment

[0054]

[0055] The yield (114.5 kg / mu), average price (31.90 yuan / kg), and output value (3652.55 yuan / mu) of treatment 3 were significantly higher than those of the control group and treatments 1 and 2.

[0056] Overall conclusion: Treatment 3 (jointing and topping method) performed best in improving plant structure, tobacco quality and economic benefits, and was significantly superior to traditional topping methods and other treatments.

[0057] Experiment 2:

[0058] For tobacco plants with poor growth, topping was performed. One control and three treatments were set up, with 1200 plants per treatment. In the control, conventional production procedures were followed: when the flower buds were still enclosed within the top leaves and about the size of a pea, the young leaves were carefully parted, and the buds were removed with tweezers or small bamboo sticks. In treatment 1, the bud and the two leaves below it were removed before topping. In treatment 2, the bud and the two leaves below it were removed before topping, and the plants were removed after three leaves. In treatment 3, when the internode length increased to 5cm and the number of leaves was 18, topping was performed again, leaving 3-5cm of stem above the top leaves. The plant height after topping was 90-95cm. Agronomical traits were measured one day before curing. After curing, the appearance quality of the tobacco leaves and the smoking quality (X2F, C3F, B2F) were measured, along with the percentage of high-quality tobacco, average price, and average yield per acre.

[0059] Table 6. Agronomic traits of tobacco leaves under each treatment

[0060]

[0061] Treatment 3 resulted in a cylindrical plant shape with high-quality tobacco leaves and 18 leaves. Treatment 3 significantly increased plant height (93.6 cm) and the number of effective leaves (16 leaves), forming a cylindrical tobacco plant, which was superior to the control group and the umbrella shape of treatments 1 and 2.

[0062] Table 7 Evaluation of the appearance quality of tobacco leaves under each treatment

[0063]

[0064] The tobacco leaves of treatment 3 were orange-yellow in color, had a bright luster, sufficient oil content, loose texture, and good elasticity, which was superior to the other treatment groups.

[0065] Table 8 Chemical composition of tobacco leaves under different treatments

[0066]

[0067] Treatment 3 showed that the total sugar, reducing sugar, total nitrogen, nicotine, potassium chloride, and sugar / alkali ratio were all within the standard range in the lower, middle, and upper parts of the sample. The control group and treatments 1 and 2 showed that some indicators were lower and higher.

[0068] Table 9 Sensory quality evaluation of tobacco leaves for each treatment

[0069]

[0070] Treatment 3 scored the highest in terms of aroma quality, aroma quantity, and off-odors (75.5 points), which was significantly better than the control group (68.5 points) and treatments 1 and 2.

[0071] Table 10 Economic traits of tobacco leaves under each treatment

[0072]

[0073] The yield (116.4 kg / mu), average price (32.12 yuan / kg), and output value (3738.768 yuan / mu) of treatment 3 were significantly higher than those of the control group and treatments 1 and 2.

[0074] Overall conclusion: Treatment 3 (jointing and topping method) performed best in improving plant type, tobacco quality and economic benefits, and was significantly superior to traditional topping methods and other treatments.

[0075] Experiment 3:

[0076] For tobacco plants with average growth, topping was performed. One control and three treatments were set up, with 1200 plants per treatment. In the control, conventional production procedures were followed. When the flower buds reached 4-6 cm in length and were clearly separated from the young leaves, the flower buds, flower stalks, and 2-3 small leaves below them were removed. In treatment 1, topping was performed at the beginning of flower bud formation. In treatment 2, topping was performed when the flower buds and young leaves began to separate. In treatment 3, topping was performed when the internode length reached 5 cm and the number of leaves was around 20. After topping, 3-5 cm of stem was left above the top leaves, resulting in a plant height of 100-105 cm. Agronomical traits were measured one day before curing. After curing, the appearance quality of the tobacco leaves and the smoking quality (X2F, C3F, B2F) were measured, along with the percentage of high-quality tobacco, average price, and average yield per acre.

[0077] Table 11 Agronomic traits of tobacco leaves under each treatment

[0078]

[0079] Treatment 3 resulted in a cylindrical plant shape with high-quality tobacco leaves and 20 leaves. Treatment 3 significantly increased plant height (104.9 cm) and the number of effective leaves (18 leaves), forming a cylindrical tobacco plant, which was superior to the control group and the umbrella shape of treatments 1 and 2.

[0080] Table 12 Evaluation of the appearance quality of tobacco leaves under different treatments

[0081]

[0082] The tobacco leaves of treatment 3 were orange-yellow in color, glossy, rich in oil, loose in texture, and elastic, which was superior to those of other treatment groups.

[0083] Table 13 Chemical components of tobacco leaves under different treatments

[0084]

[0085] Treatment 3 showed that the total sugar, reducing sugar, total nitrogen, nicotine, potassium chloride, and sugar / alkali ratio were all within the standard range in the lower, middle, and upper parts of the sample. The control group and treatments 1 and 2 showed that some indicators were lower and higher.

[0086] Table 14 Sensory quality evaluation of tobacco leaves for each treatment

[0087]

[0088] Treatment 3 scored the highest in terms of aroma quality, aroma quantity, and off-odors (78.5 points), which was significantly better than the control group (72.5 points) and treatments 1 and 2.

[0089] Table 15 Economic traits of tobacco leaves under different treatments

[0090]

[0091] The yield (126.2 kg / mu), average price (33.43 yuan / kg), and output value (5232.666 yuan / mu) of treatment 3 were significantly higher than those of the control group and treatments 1 and 2.

[0092] Experiment 4:

[0093] For tobacco plants with good growth, topping was performed. One control and three treatments were set up, with 1200 plants per treatment. In the control, the topping was performed according to standard production procedures, removing the entire inflorescence along with its two lower leaflets when the first central flower on the main axis just opened. In treatment 1, topping was performed when the first central flower opened, removing the entire inflorescence along with its three lower leaflets. In treatment 2, topping was performed when the first central flower opened, removing the entire inflorescence along with its four lower leaflets. In treatment 3, when the internode length increased by 5cm, the number of leaves was 22, and the plant height after topping was 110-115cm. Agronomical traits were measured one day before curing. After curing, the appearance quality of the tobacco leaves and the smoking quality (X2F, C3F, B2F) were measured, along with the percentage of high-quality tobacco, average price, and average yield per acre.

[0094] Table 16 Agronomic traits of tobacco leaves under each treatment

[0095]

[0096] Treatment 3 resulted in a cylindrical plant shape with high-quality tobacco leaves and 22 leaves. Treatment 3 significantly increased plant height (114.2 cm) and the number of effective leaves (20 leaves), forming a cylindrical tobacco plant, which was superior to the control group and the umbrella shape of treatments 1 and 2.

[0097] Table 17 Evaluation of the appearance quality of tobacco leaves under different treatments

[0098]

[0099] The tobacco leaves of treatment 3 were orange-yellow in color, glossy, rich in oil, loose in texture, and elastic, which was superior to those of other treatment groups.

[0100] Table 18 Chemical components of tobacco leaves under different treatments

[0101]

[0102] Treatment 3 showed that the total sugar, reducing sugar, total nitrogen, nicotine, potassium chloride, and sugar / alkali ratio were all within the standard range in the lower, middle, and upper parts of the sample. The control group and treatments 1 and 2 showed that some indicators were lower and higher.

[0103] Table 19 Sensory quality evaluation of tobacco leaves for each treatment

[0104]

[0105] Treatment 3 scored the highest in terms of aroma quality, aroma quantity, and off-odors (84 points), which was significantly better than the control group (74 points) and treatments 1 and 2.

[0106] Table 20 Economic traits of tobacco leaves under each treatment

[0107]

[0108] The yield (143.4 kg / mu), average price (34.78 yuan / kg), and output value (5232.666 yuan / mu) of treatment 3 were significantly higher than those of the control group and treatments 1 and 2.

[0109] Experiment 5:

[0110] Topping was performed on vigorous tobacco plants, with one control and three treatments, each consisting of 1200 plants. In the control, the entire inflorescence, including the two leaflets below it, was removed when the plant was in full bloom or at its peak flowering stage, following standard production procedures. In treatment 1, the entire inflorescence, including the three leaflets below it, was removed when the plant was in full bloom or at its peak flowering stage. In treatment 2, the entire inflorescence, including the four leaflets below it, was removed when the plant was in full bloom or at its peak flowering stage. In treatment 3, topping was performed when the internode length increased by 5cm and the number of leaves reached 24. After topping, the plant height was 120-125cm. Agronomical traits were measured one day before curing. The appearance quality and smoking quality of the cured tobacco leaves (X2F, C3F, B2F), the percentage of high-quality tobacco, and the average price and yield per acre were determined.

[0111] Table 21 Agronomic traits of tobacco leaves under each treatment

[0112]

[0113] Treatment 3 resulted in a cylindrical plant shape with high-quality tobacco leaves and 24 leaves. Treatment 3 significantly increased plant height (125.0 cm) and the number of effective leaves (22 leaves), forming a cylindrical tobacco plant, which was superior to the control group and the umbrella shape of treatments 1 and 2.

[0114] Table 22 Evaluation of the appearance quality of tobacco leaves under different treatments

[0115]

[0116] The tobacco leaves of treatment 3 were orange-yellow in color, glossy, rich in oil, loose in texture, and elastic, which were significantly better than those of the control group and treatments 1 and 2.

[0117] Table 23 Chemical components of tobacco leaves under different treatments

[0118]

[0119] Treatment 3 showed that the total sugar, reducing sugar, total nitrogen, nicotine, potassium chloride, and sugar / alkali ratio were all within the standard range in the lower, middle, and upper parts of the sample. The control group and treatments 1 and 2 showed that some indicators were lower and higher.

[0120] Table 24 Sensory quality evaluation of tobacco leaves for each treatment

[0121]

[0122] Treatment 3 achieved the highest total score (84 points) across all indicators, including aroma quality (9 points), aroma quantity (9 points), off-odors (9 points), concentration (9 points), strength (8 points), irritation (10 points), aftertaste (9.5 points), flammability (9 points), and grayness (8.5 points), significantly outperforming the control group (74 points) and Treatments 1 and 2.

[0123] Table 5 Economic traits of tobacco leaves under each treatment

[0124]

[0125] The yield (147.3 kg / mu), average price (34.78 yuan / kg), and output value (5123.09 yuan / mu) of treatment 3 were significantly higher than those of the control group and treatments 1 and 2, demonstrating a significant improvement in economic benefits.

[0126] Comprehensive Analysis and Overall Conclusion:

[0127] Through detailed analysis of the five sets of experiments (Experiments 1 to 5), the following comprehensive conclusions can be drawn:

[0128] The jointing and topping method (treatment 3) can effectively improve the plant structure under various tobacco plant growth conditions, forming cylindrical tobacco plants and increasing the number of effective leaves.

[0129] Treatment 3 was significantly superior to the traditional topping method (control group) and other treatments (treatment 1 and treatment 2) in terms of appearance quality, chemical composition and sensory quality of tobacco leaves, thus improving the overall quality of tobacco leaves.

[0130] In terms of economic traits, treatment 3 consistently achieved higher yields, better market prices, and higher per-acre returns, demonstrating significant economic benefits and bringing greater economic benefits to tobacco farmers.

[0131] The jointing and topping method has strong adaptability and promotion value, especially suitable for low-latitude, high-altitude tobacco areas. It can effectively cope with complex and changeable climate and soil conditions, improve tobacco yield and quality, increase farmers' income, and promote the sustainable development of the flue-cured tobacco industry.

[0132] The method of jointing and topping of the present invention optimizes the growth structure of tobacco plants through scientific classification and precise operation, improves the appearance quality and internal quality of tobacco leaves, overcomes the limitations of traditional topping methods in low-latitude, high-altitude tobacco areas, and has broad application prospects and promotion value.

[0133] To verify the effect of leaving 3-5 cm of stem above the top leaves after topping, the applicant used this method for topping, the traditional topping method (control group), and other treatments (treatment 1, treatment 2, treatment 3, treatment 4, treatment 5). The samples with topping were examined for the necrosis rate (%) of the last 1-2 leaves and the incidence of empty stem disease (%). The results are as follows:

[0134]

[0135] The results showed that the necrosis rate (%) of the last 1-2 leaves after topping and the incidence rate (%) of empty stem disease were both lower than those of other methods, and the overall incidence rate was also lower than that of other methods.

[0136] Final conclusion:

[0137] The topping method proposed in this invention significantly improves the plant structure of Yunyan 87 tobacco plants by scientifically adjusting the timing of topping and the number of leaves retained, combined with reasonable fertilization management. This enhances the appearance, chemical composition, and sensory quality of the tobacco leaves, and substantially increases yield and economic benefits. This method effectively solves the problems of unreasonable plant population structure and low tobacco yield and quality in low-latitude, high-altitude tobacco-growing areas in existing technologies, providing strong support for the sustainable development of the flue-cured tobacco industry and possessing significant practical significance and application value. Furthermore, using this topping method, the necrosis rate (%) of the last 1-2 leaves and the incidence rate (%) of empty stem disease are both lower than with other methods, and the overall disease incidence is also lower.

[0138] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for topping Yunyan 87 tobacco plants suitable for low-latitude, high-altitude tobacco-growing areas, characterized in that, The method is as follows: Transplanting was completed between April 25 and May 5; The tobacco plants were divided into five categories: early flowering, poor growth, average growth, relatively good growth, and good growth. Appropriate topping treatments were applied based on their different growth conditions. The specific methods are as follows: 1) The method for early flowering topping is to top when the internode lengthens to 5 cm and the number of leaves is 16. Then top the plant and leave 3-5 cm of stem above the top leaves. The plant height after topping is 80-85 cm. 2) The method for pruning the plant with poor growth is to prune it when the internode lengthens to 5 cm and the number of leaves is 18. After pruning, leave 3-5 cm of stem above the top leaves. The plant height after pruning is 90-95 cm. 3) The method of topping when the plant is growing well is to top when the internode lengthens to 5 cm and the number of leaves is 20. After topping, leave 3-5 cm of stem above the top leaves. The plant height after topping is 100-105 cm. 4) The method for pruning plants with good growth is to prune them when the internode length is 5 cm and the number of leaves is 22. After pruning, leave 3-5 cm of stem above the top leaves. The plant height after pruning is 110-115 cm. 5) The method for topping when the plant is growing well is to top when the internode lengthens to 6 cm and the number of leaves is 24. After topping, leave 3-5 cm of stem above the top leaves. The plant height after topping should be 120-125 cm. When topping early flowering, the method of topping flowers without topping leaves should be used.

2. The method for topping Yunyan 87 according to claim 1, characterized in that, The fertilization requirements for the method are as follows: Medium-fertility tobacco fields: Apply 60 to 65 kg of base fertilizer per mu; For tobacco fields with medium to high fertility: apply 50 to 55 kg of base fertilizer per mu; Organic fertilizer application: ≥70 kg / mu of commercial organic fertilizer, or 300 kg to 500 kg / mu of farmyard manure; Potassium fertilizer: Apply 10 to 15 kg per mu; Superphosphate: Apply 20 kg per acre; Special top dressing: Apply 18 kg per mu; Seedling fertilizer: Apply 2.5 kg per mu.

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