Laser irradiation method for flue-cured tobacco seedling culture

Abstract

The invention relates to the technical field of flue-cured tobacco planting, in particular to a laser irradiation method for flue-cured tobacco seedling culture. The method comprises the following steps: performing laser irradiation treatment in a stage from flue-cured tobacco sowing to seedling hardening; the illumination intensity of the laser is 0.2-0.4 mu mol.m <-2 >. S <-1 >, the light intensity ratio of the red laser to the blue laser is 1.5: 1, and the single-day irradiation duration of the laser is less than or equal to 16 hours. The laser irradiation treatment is carried out in the flue-cured tobacco floating seedling raising stage, the flue-cured tobacco light energy utilization rate is increased, dry matter accumulation is promoted, the tobacco seedling quality is improved, the transplanted flue-cured tobacco is promoted to grow robustly, and finally the yield and the first-class tobacco rate of the flue-cured tobacco are increased.

Description

Technical Field

[0001] The invention relates to the technical field of flue-cured tobacco planting, and in particular to a laser irradiation method for growing flue-cured tobacco seedlings. Background Art

[0002] As the core link of the flue-cured tobacco production system, the technical management of flue-cured tobacco seedlings directly affects the morphological construction and physiological metabolism of tobacco seedlings, and is a key prerequisite for determining the growth potential of tobacco plants in the field and the quality of tobacco leaves. The technical iteration from traditional seedbed direct seeding, tray seedlings to modern floating seedlings reflects the trend of flue-cured tobacco agriculture towards precision and intensive development. The current mainstream floating seedling technology can cultivate standardized tobacco seedlings with strong root vitality, strong seedlings, and high overall quality under the control of ideal environmental parameters through substrate replacement, water-fertilizer coupling and other means, laying the foundation for the cultivation of high-quality and high-yield tobacco leaves.

[0003] Although the floating seedling technology of flue-cured tobacco has been widely used, the relevant agronomic technology still needs to be updated to better improve the quality and yield of flue-cured tobacco. In low-latitude tobacco-growing areas such as the Yunnan-Guizhou Plateau in my country, seasonal light shortages constitute a significant technical constraint. Taking the typical tobacco-growing areas in Guizhou as an example, floating seedling cultivation of flue-cured tobacco is generally carried out in plastic greenhouses from February to April each year. During this period, the light intensity and time are relatively low throughout the year. Seedling cultivation in plastic greenhouses often faces the phenomenon that the light intensity cannot meet the light compensation point of the tobacco seedlings, which can easily lead to low photosynthetic efficiency of the tobacco seedlings, poor growth, and prolonged seedling recovery period after transplanting, which will ultimately affect the economic benefits such as the proportion of high-quality tobacco and yield.

[0004] At present, there are various agronomic techniques to improve the quality and yield of flue-cured tobacco, including increasing the application of organic fertilizer, adjusting the sowing time, adopting a non-tillage method, spraying plant growth regulators, etc. Unlike these technologies, laser irradiation technology can optimize the light environment for plant growth, improve photosynthetic efficiency, and promote the growth of strong seedlings. However, laser irradiation technology in the past was mostly used for soil seedling cultivation or crop planting, and was rarely used for soilless seedling cultivation. For example, CN115589892A improved the quality of tea leaves and increased the yield by laser supplementary light treatment at three growth stages of tea trees. For example, CN114521410B irradiated rice seedlings with laser and found that it could promote strong seedlings, improve the utilization rate of light energy, and have significant energy-saving effects compared with traditional LED lamps. For example, CN116491386A treats the buds of cactus plants before they form and grow, which can increase buds and flowers, and also improve the development of the root system. It can be seen that the application prospects of plant supplementary lighting with laser as the light source are broad, and it is of great significance to explore its application methods and effects on different crops, but research reports on floating seedling cultivation of flue-cured tobacco are relatively rare. Therefore, it is urgent to solve the problem. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a laser irradiation method for flue-cured tobacco seedling cultivation, which promotes the robust growth of flue-cured tobacco seedlings and improves the quality of flue-cured tobacco seedlings by optimizing the laser light quality ratio, irradiation time and laser intensity.

[0006] To achieve the above object, the technical solution of the present invention is implemented as follows: a laser irradiation method for flue-cured tobacco seedling cultivation, characterized in that the method comprises: laser irradiation treatment is performed during the growth stage from sowing to before hardening of the seedlings, the growth stage of the flue-cured tobacco treated with laser irradiation is the seedling stage, and after reaching the seedling standard, the laser light source is turned off, and the seedlings are hardened and transplanted to the field.

[0007] Preferably, the laser irradiation treatment process includes:

[0008] 1) Arrange the laser light source for laser irradiation in the seedling shed, and adjust the hanging height according to the seedling shed, keep the laser light source 3-4 meters away from the seedling pool, and the coverage area of ​​each light source is 30-40 square meters, adjust the light source projection angle to make the light field evenly distributed;

[0009] 2) Before raising tobacco seedlings, the site and the seedling greenhouse are thoroughly disinfected, and clean water and special seedling fertilizer are added to the seedling pool and mixed evenly; after the substrate is loaded on the tray, the tobacco is sown in the center of the seedling hole, the seeded seedling tray is placed flat on the seedling pool, and the laser light source is turned on to irradiate the tobacco on the seedling tray.

[0010] Preferably, the laser light intensity is 0.2 to 0.4 μmol·m -2 ·s -1 .

[0011] Preferably, the laser irradiation method uses a red laser with a wavelength of 660±5nm and a blue laser with a wavelength of 450±5nm, and the light intensity ratio of the red laser to the blue laser is 1.5:1.

[0012] Preferably, the laser irradiation time is 5:00-21:00 every day, and the laser irradiation time per day is ≤16 hours; the laser irradiation technology needs to be combined with outdoor natural light. On sunny days with sufficient sunlight and high temperatures, the laser light source is turned off for two hours between 11:30 and 13:30 at noon.

[0013] Preferably, the laser irradiation uses a semiconductor laser, and the semiconductor laser is installed on the shelf of the seedling greenhouse, and the laser irradiated vertically downward is evenly irradiated onto the seedling tray planted with flue-cured tobacco.

[0014] Preferably, the flue-cured tobacco seedling raising method is floating seedling raising, which is soilless seedling raising in flue-cured tobacco production. The seedling raising period is carried out in a greenhouse, and after the seedlings are mature, they are transplanted to the field after seedling training, which is the basis for cultivating high-quality tobacco seedlings and achieving high yield and high quality of flue-cured tobacco in the later stage.

[0015] The beneficial effects of the present invention are embodied in:

[0016] (1) The method provided by the present invention adopts laser irradiation technology as a new type of supplementary lighting. Compared with traditional light sources, lasers have the characteristics of high photoelectric conversion efficiency, more precise wavelength, and significant coherence. In crop supplementary lighting applications, laser products have the advantages of improving electron transfer efficiency, improving light energy utilization, and reducing energy consumption. They have a large effective distance range and are more suitable for greenhouse seedling cultivation than LEDs. Reasonable use of laser irradiation can effectively improve the lighting environment of tobacco seedlings, and help reduce the occurrence of problems such as weak tobacco seedlings and diseases caused by insufficient natural light, thereby enhancing the stress resistance of tobacco seedlings and reducing seedling risks.

[0017] (2) The method provided by the present invention improves the photosynthesis efficiency of flue-cured tobacco, increases dry matter accumulation, improves the quality of tobacco seedlings, and cultivates strong tobacco seedlings, laying a foundation for high yield and high quality of flue-cured tobacco by regulating light quality ratio and light intensity.

[0018] (3) The method provided by the present invention applies laser irradiation technology in tobacco seedling greenhouses at different altitudes in the same province. It is found that the method provided by the present invention significantly improves the quality of flue-cured tobacco leaves and reduces the impact of altitude on the growth of flue-cured tobacco, thereby increasing the rate of high-quality tobacco and the yield, and has the prospect of large-scale application and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a morphological diagram of the high-altitude tobacco seedlings at the seedling stage of the present invention;

[0020] Figure 2 This is a morphological diagram of the low-altitude tobacco seedlings in the seedling stage of the present invention. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] Example 1

[0023] The test site is a high-altitude specialized seedling nursery in Guizhou Province. The flue-cured tobacco seedlings are grown using floating seedling technology, and the flue-cured tobacco variety selected is Yunyan 87.

[0024] Laser device was used for irradiation, and the four treatment test groups had red and blue laser ratios of 9:2 (9R2B), 9:3 (9R3B), 9:6 (9R6B), and 9:9 (9R9B); the red laser wavelength was 660nm±5nm, and the blue laser wavelength was 450nm±5nm.

[0025] Implementation steps

[0026] 1) Arrange the laser light source in the seedling shed, adjust the hanging height according to the seedling shed, keep the laser device 3-4 meters away from the seedling pool, each lamp covers about 30-40 square meters, adjust the light source projection angle to make the light field evenly distributed;

[0027] Before the flue-cured tobacco floating seedlings are raised, the site and the seedling greenhouse are fully disinfected. Clean water and special seedling fertilizer are added to the seedling pool and mixed evenly. After the substrate is placed on the tray, it is sown in the center of the seedling hole, and the seeded seedling tray is placed flat in the seedling pool to start laser irradiation. A red laser with a wavelength of 660±5nm and a blue laser with a wavelength of 450±5nm are used as light sources. The ratio of red and blue lasers is adjusted to 9:2, 9:3, 9:6 and 9:9, and the light intensity is 0.2-0.4μmol·m -2 ·s -1 The photoperiod was set at 5:00-21:00. On sunny days with sufficient sunlight and high temperature, the laser light source was turned off for two hours between 11:30 and 13:30.

[0028] 3) During the above step 2), the daily management of flue-cured tobacco floating seedlings is followed. Ventilate in time from sowing to pre-emergence stage; after emergence, manage by intermittent ventilation to avoid excessive humidity and dehumidify and ventilate; the temperature of the seedbed cannot be higher than 30°C; when the tobacco seedlings grow to the small cross stage to the large cross stage, thin the seedlings and add fertilizer to each tray. After the tobacco seedlings are sealed in the tray, cut the leaves 2-3 times, and when the tobacco seedlings reach the seedling standard, turn off the laser light source, and transplant them to the field after hardening.

[0029] 4) Take 10-20 tobacco seedlings at the seedling stage to measure the stem height (the height from the stem base to the growth point on the ground), stem circumference (measure the middle stem with a soft tape measure), fresh weight of the whole plant, fresh weight of the above-ground and underground parts, dry weight of the above-ground and underground parts (weighed after oven drying and cooling), and seedling index. The seedling index calculation formula is as follows:

[0030] Seedling index = [(stem girth / plant height + root-crown dry weight ratio) × total dry weight × 100]

[0031] 60 days after transplanting into the field, the stem girth, number of effective leaves, maximum leaf length (straight line length from the junction of the stem and leaves to the leaf tip), maximum leaf width, inverted trefoil length and inverted trefoil width were measured. The measurement was repeated for 3 groups of 5 tobacco plants in a group.

[0032] After the flue-cured tobacco matures, the leaves are harvested and graded, and economic indicators such as per-acre yield, average price, per-acre output value, high-quality tobacco rate and medium tobacco rate are calculated.

[0033] The four test groups in Example 1 were labeled 9R2B, 9R3B, 9R6B and 9R9B, respectively.

[0034] Comparative Example 1

[0035] The test materials and seedling raising methods were the same as those of the experimental group. In the implementation steps 2) to 3), no laser light source was set, no laser treatment was performed, and only natural light was used as CK.

[0036] Data analysis was performed using software such as IBM SPSS Statistics 27 and Excel 2021.

[0037] The statistics of agronomic traits during the seedling stage are shown in Table 1-2.

[0038] Table 1

[0039]

[0040] The dry weight and seedling index at the seedling stage are shown in Table 2 below.

[0041] Table 2

[0042]

[0043] After the tobacco seedlings reached the seedling standard, they were hardened and transplanted to the field. The agronomic traits of the flue-cured tobacco 60 days after transplanting were statistically analyzed, as shown in Table 3 below.

[0044] Table 3

[0045]

[0046] After the flue-cured tobacco matures, the tobacco leaves are harvested and the economic traits of the tobacco leaves are statistically analyzed, as shown in Table 4 below.

[0047] Table 4

[0048]

[0049] Results and Analysis

[0050] The above data show that compared with the control group (CK), the 9R6B and 9R9B treatments in the seedling stage have significantly better effects. The root length of tobacco seedlings increased by 5.2%-15.2%; the accumulation of aboveground dry matter increased by 13.84% and 8.18% respectively; the seedling index increased by 4.27%-19.97%. In the field period, the stem girth of tobacco seedlings increased significantly, and the maximum leaf area also increased. After picking, the statistical analysis of economic traits showed that the per mu yield, per mu output value and the proportion of high-quality tobacco in the treatment group were higher than those in the control group (CK). The per mu yield increased by 4.19%-15.62%; the per mu output value increased by 3.44%-23.55%; except for the 9R3B group, which decreased by 0.71%, the average price of the other groups increased by 0.94%-6.86%; the rate of high-quality tobacco in the flue-cured tobacco grade increased by 3.62%-67.43%. The comprehensive comparison results show that the technical scheme of the present invention has a promoting effect on the agronomic traits of flue-cured tobacco in the seedling stage, and both dry matter accumulation and seedling index are increased; the results after the mature and harvested flue-cured tobacco also further show that the yield and proportion of high-quality tobacco after laser irradiation treatment are increased, and the economic benefits of flue-cured tobacco are improved.

[0051] Example 2

[0052] The test site is a low-altitude specialized seedling nursery. The flue-cured tobacco seedlings are grown using floating seedling technology, and the flue-cured tobacco variety selected is Yunyan 87.

[0053] Laser device was used for irradiation, and the four treatment test groups had red and blue laser ratios of 3:9 (3R9B), 6:9 (6R9B), 9:6 (9R6B), and 9:9 (9R9B); the red laser wavelength was 660nm±5nm, and the blue laser wavelength was 450nm±5nm.

[0054] Implementation steps

[0055] 1) Arrange the laser light source in the seedling shed, adjust the hanging height according to the seedling shed, keep the laser device 3-4 meters away from the seedling pool, each lamp covers about 30-40 square meters, adjust the light source projection angle to make the light field evenly distributed;

[0056] 2) Before the floating seedling cultivation of flue-cured tobacco, the site and the seedling greenhouse are fully disinfected, and clean water and special seedling fertilizer are added to the seedling pool and mixed evenly. After the substrate is loaded on the tray, it is sown in the center of the seedling hole, and the seeded seedling tray is placed flat in the seedling pool, and laser irradiation treatment is started. A red laser with a wavelength of 660±5nm and a blue laser with a wavelength of 450±5nm are used as light sources. The ratio of red and blue lasers is adjusted to 3:9, 6:9, 9:6 and 9:9, and the light intensity is 0.2-0.4μmol·m -2 ·s -1The photoperiod was set at 5:00-21:00. On sunny days with sufficient sunlight and high temperature, the laser light source was turned off for two hours between 11:30 and 13:30.

[0057] 3) During the above step 2), the daily management of flue-cured tobacco floating seedlings is followed. Ventilate in time from sowing to pre-emergence stage; after emergence, manage by intermittent ventilation to avoid excessive humidity and dehumidify and ventilate; the temperature of the seedbed cannot be higher than 30°C; when the tobacco seedlings grow to the small cross stage to the large cross stage, thin the seedlings and add fertilizer to each tray. After the tobacco seedlings are sealed in the tray, cut the leaves 2-3 times, and when the tobacco seedlings reach the seedling standard, turn off the laser light source, and transplant them to the field after hardening.

[0058] 4) During the seedling stage, 10-20 tobacco seedlings were taken to measure the stem height (the height from the stem base on the ground surface to the growth point), stem circumference (a soft tape measure was used to measure the middle stem), fresh weight of the whole plant, fresh weight of the above-ground and underground parts, dry weight of the above-ground and underground parts (weighed after oven drying and cooling), and seedling index.

[0059] The calculation formula of seedling index is as follows:

[0060] Seedling index = [(stem girth / plant height + root-crown dry weight ratio) × total dry weight × 100]

[0061] 60 days after transplanting into the field, the stem girth, number of effective leaves, maximum leaf length (straight line length from the junction of the stem and leaves to the leaf tip), maximum leaf width, inverted trefoil length and inverted trefoil width of the flue-cured tobacco were measured. The measurement was repeated for 3 groups of 5 tobacco plants.

[0062] After the flue-cured tobacco matures, the leaves are harvested and graded, and economic indicators such as per-acre yield, average price, per-acre output value, high-quality tobacco rate and medium tobacco rate are calculated.

[0063] The four test groups in Example 1 were labeled 3R9B, 6R9B, 9R6B and 9R9B, respectively.

[0064] Comparative Example 2

[0065] The test materials and seedling raising methods were the same as those of the experimental group. In the implementation steps 2) to 3), no laser light source was set, no laser treatment was performed, and only natural light was used as CK.

[0066] IBM SPSS Statistics 27 and Excel 2021 were used for data analysis and graphing.

[0067] The statistics of agronomic traits at the seedling stage are shown in Table 5 below.

[0068] Table 5

[0069]

[0070] The dry weight and seedling index at the seedling stage are shown in Table 6 below.

[0071] Table 6

[0072]

[0073] After the tobacco seedlings reached the seedling standard, they were hardened and transplanted to the field. The agronomic traits of the flue-cured tobacco 60 days after transplanting were statistically analyzed, as shown in Table 7 below.

[0074] Table 7

[0075]

[0076] After the flue-cured tobacco matures, the tobacco leaves are harvested and the economic traits of the flue-cured tobacco are statistically analyzed as shown in Table 8 below.

[0077] Table 8

[0078]

[0079] Results and Analysis

[0080] From the above data, it can be seen that compared with the control CK, the growth of tobacco seedlings in the four test groups during the seedling stage was greater, and the stem height and stem girth increased significantly; the dry weight of the above-ground and underground parts increased by 42.65%-124.26% and 29.03%-45.16% respectively compared with CK, and the tobacco seedling strong seedling index increased by 43.38%-72.72%; the maximum leaf area during the field stage increased significantly; statistics on economic traits after picking showed that the per mu yield, per mu output value and high-quality tobacco rate of the laser-treated group were higher than those of the CK group; its per mu yield increased by 4.13%-12.89%; per mu output value increased by 6.10%-17.72%; the average price increased by 1.89%-4.28%; and the high-quality tobacco rate increased by 1.02%-5.13%. Comprehensive comparison shows that the technical scheme of the present invention has a good promoting effect on the agronomic traits of flue-cured tobacco seedlings, especially the fresh weight and dry weight of the above-ground and underground parts, and significantly improves the quality of tobacco seedlings, thereby facilitating the growth of tobacco plants after transplanting, and achieving an increase in the rate of high-quality tobacco and an increase in yield.

[0081] The results of Example 1 and Example 2 both show that the method provided by the present invention can promote the cultivation effect of flue-cured tobacco in floating seedling cultivation, improve the quality of tobacco seedlings, and further increase the yield and quality of flue-cured tobacco leaves, and the effect is best after 9B6R treatment.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser irradiation method for flue-cured tobacco seedling cultivation, characterized in that: The method comprises: performing laser irradiation treatment during the growth stage from sowing to before hardening of the seedlings of flue-cured tobacco.

2. The laser irradiation method for flue-cured tobacco seedling cultivation according to claim 1, characterized in that: The laser irradiation treatment process includes: 1) Arrange the laser light source for laser irradiation in the seedling shed, and adjust the hanging height according to the seedling shed, keep the laser light source 3-4 meters away from the seedling pool, and the coverage area of ​​each light source is 30-40 square meters, adjust the light source projection angle to make the light field evenly distributed; 2) Before raising tobacco seedlings, the site and the seedling greenhouse are thoroughly disinfected, and clean water and special seedling fertilizer are added to the seedling pool and mixed evenly; after the substrate is loaded on the tray, the tobacco is sown in the center of the seedling hole, the seeded seedling tray is placed flat on the seedling pool, and the laser light source is turned on to irradiate the tobacco on the seedling tray.

3. The laser irradiation method for flue-cured tobacco seedling cultivation according to claim 2, characterized in that: The illumination intensity of the laser is 0.2 to 0.4 μmol·m -2 ·s -1 .

4. The laser irradiation method for flue-cured tobacco seedling cultivation according to claim 2, characterized in that: The laser irradiation method uses a red laser with a wavelength of 660±5nm and a blue laser with a wavelength of 450±5nm, and the light intensity ratio of the red laser to the blue laser is 1.5:

1.

5. The laser irradiation method for flue-cured tobacco seedling cultivation according to claim 2, characterized in that: The laser irradiation time is 5:00-21:00 every day, and the laser irradiation time per day is ≤16h; the laser irradiation technology needs to be combined with outdoor natural light.

6. The laser irradiation method for flue-cured tobacco seedling cultivation according to claim 2, characterized in that: The laser irradiation adopts a semiconductor laser, which is installed on the shelf of the seedling greenhouse. The laser irradiated vertically downward is evenly irradiated on the seedling tray planted with flue-cured tobacco.

7. A laser irradiation method for growing flue-cured tobacco seedlings according to claim 1 or 2 or 3 or 4 or 5 or 6, characterized in that: The method of flue-cured tobacco seedling cultivation is floating seedling cultivation, which is soilless seedling cultivation in flue-cured tobacco production.

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