Tobacco seedling raising method

Abstract

The present application belongs to the technical field of tobacco planting, and discloses a tobacco seedling raising method, which comprises the following steps: setting up a seedling shed and building a seedling pool, preparing a paper pot disc filled with a substrate, sowing tobacco seeds in the substrate, water management, fertilizer management, temperature management, disease and pest control and the like, wherein the water management adopts a dry-wet alternating watering step in the seedling stage, so that the water content of the substrate reaches 70-80%. The water supply of the substrate in the paper pot disc is conveniently controlled by the seedling raising personnel, the development of the tobacco seeds in the paper pot disc is ensured, and the pool bottom level requirement is reduced.

Description

Technical Field

[0001] This invention relates to the field of tobacco planting technology, and in particular to a method for raising tobacco seedlings. Background Technology

[0002] Currently, tobacco cultivation in my country mainly employs two methods: tray seedling raising and floating seedling raising. However, both methods require individual loading of seedlings into transplanting machines during transplanting. To improve transplanting efficiency, tobacco experts have begun considering using foldable paper trays for seedling raising, enabling continuous transplanting. However, paper trays are inherently unsuitable for floating seedling raising, while tray seedling raising presents challenges in controlling the moisture supply to the substrate within the paper trays.

[0003] Therefore, there is an urgent need for a tobacco seedling cultivation method to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a method for raising tobacco seedlings, which maintains the substrate at a moisture content of 70-80% to facilitate the development of tobacco seeds, ensures the development of tobacco seeds in paper pots, and reduces the required water level at the bottom of the pot.

[0005] To achieve this objective, the present invention adopts the following technical solution: a tobacco seedling cultivation method, comprising the following steps:

[0006] 1) Construct seedling sheds and seedling ponds;

[0007] 2) Prepare paper pots filled with substrate, sow tobacco seeds in the substrate, and place the paper pots into the seedling bed;

[0008] 3) Moisture management: Add water to the seedling bed to bring the moisture content of the substrate to 70-80% until the seedlings emerge. Wait for the moisture in the substrate in the paper pot to evaporate naturally until the moisture content of the substrate is less than 55%. Water the seedling bed. After the moisture content of the substrate reaches 70-80%, repeat the steps of waiting for the moisture in the substrate to evaporate naturally and then watering until the seedlings are transplanted.

[0009] 4) Fertilizer management: 8-12 days after sowing, when 70-80% of the seeds have emerged, apply the first top dressing of water-soluble fertilizer for tobacco seedling cultivation. After emergence, increase the concentration of the water-soluble fertilizer in stages according to the development stage of the tobacco seedlings. During the seedling period, water and fertilizer management is carried out by alternating between applying water-soluble fertilizer twice and adding water once.

[0010] 5) Temperature management: After sowing, control the temperature inside the greenhouse to be maintained in the range of 20℃-28℃; after emergence, control the temperature inside the greenhouse to be maintained in the range of 22℃-30℃; after the large cross stage, control the temperature inside the greenhouse to be maintained in the range of 25℃-30℃.

[0011] 6) Pest and disease control.

[0012] Preferably, the watering volume M of the seedling bed satisfies: a×10.5ml×b≤M≤a×15.8ml×b, where a is the total number of tobacco seeds in each paper pot and b is the total number of paper pots.

[0013] Preferably, a pressurized sprinkler irrigation system is used to water the seedling ponds during water management operations.

[0014] Preferably, in water management operations, drip irrigation strips or Ф2.0-2.5cm plastic pipes are used to water the seedling ponds.

[0015] Preferably, in the fertilization management operation: from the seedling stage to the large cross stage, the water-soluble fertilizer is added at a concentration of 100-150 ppm; after the large cross stage, the water-soluble fertilizer is added at a concentration of 200 ppm.

[0016] As a preferred method, when managing water and fertilizer, water and fertilizer should be added 5-7 days after the bottom of the pond dries up, and water and fertilizer should be added again the day after the water dries up.

[0017] As a preferred method, watering should be done every 2-3 days during temperature management. If the temperature inside the greenhouse is higher than the range that should be maintained, watering should be done every 1-2 days.

[0018] As a preferred method, in pest and disease control operations, one pest control should be carried out before seedling emergence and another pest control should be carried out after entering the small cross stage. High-chlorine emamectin benzoate insecticide should be diluted and sprayed at a ratio of 1500.

[0019] As a preferred method, from the small cross stage to the large cross stage, use 0.5 kg of 50% phoxim emulsifiable concentrate mixed with 5 kg of water and 50 kg of bait to attract and kill ground beetles, crickets, mole crickets, and slugs.

[0020] As a preferred method, during the early stages of tobacco seedling growth, oligosaccharide-guanidine, oligosaccharide-chain protein, and ningnanmycin can be used to prevent secondary viral diseases; and Bacillus subtilis containing 100 billion Bacillus spores at a concentration of 5000 times can be used to prevent "two black diseases".

[0021] The beneficial effects of this invention are as follows: During the seedling stage of tobacco seed development, timely watering is provided. From emergence to transplanting, the alternating wet and dry management steps of waiting for the substrate moisture to evaporate naturally before watering are repeated, ensuring that the substrate moisture content reaches 70-80% throughout the seedling stage. By adjusting the substrate moisture content, the water supply in the paper pot trays is precisely controlled, ensuring that the tobacco seedlings are in a suitable wet and dry environment for growth, promoting seed germination and seedling growth, as well as promoting root development and enhancing the seedlings' resistance to adverse conditions. Furthermore, water and fertilizer management under the premise of alternating wet and dry water management can improve the continuity and consistency of tobacco seedling cultivation, facilitate the control of substrate moisture supply in the paper pot trays by nursery workers, reduce the amount of water and fertilizer used in seedling cultivation, and ensure the development of tobacco seeds in the paper pot trays while reducing the need for excessively high bottom levels in the seedling trays. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit the invention.

[0023] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to orientation or positional relationships and are used only for ease of description and simplification of operation. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0026] A method for raising tobacco seedlings according to an embodiment of this application includes the following steps:

[0027] 1) Construct seedling sheds and seedling ponds;

[0028] In the early stages of seedling cultivation, personnel need to construct standard-compliant seedling facilities. The specific construction steps and facility specifications are as follows:

[0029] ① Constructing seedling sheds: The sheds are longer than 40 mesh or 60 mesh, and 4.2m high. The sheds are equipped with two nets and two films (insect-proof nets of 70-80 mesh, shade nets with a shading rate of more than 50%, pond films of 100 filaments, and greenhouse films of 120 filaments. The spacing between the sheds is 1.5m. The plastic films are fixed with card slots and card springs, and sealed with anti-aging rubber strips).

[0030] ② Constructing seedling ponds: The size and number of seedling ponds are determined according to the area of ​​the seed shed. In this embodiment, a single seedling pond is 31.52m long, 1.74m wide, and 0.2m high, and the shed is equipped with 16 seedling ponds.

[0031] ③ Install an automated control system: Install a pressure tank, frequency converter, main control module, temperature and humidity sensor, drive module, power supply, etc. in the seedling shed. This enables automatic control of functions such as temperature and humidity control, automatic watering and fertilization, and pesticide spraying.

[0032] ④ Construct a water and fertilizer supply system: Based on the total seedling area of ​​the seedling pond, construct a nutrient solution pond, a water conveyance pond, a medicine pond, a stable irrigation system, and a stable water conveyance pipeline and sprinkler / drip irrigation system.

[0033] ⑤ Construct a clear water tank: The clear water tank shall be constructed with dimensions of 15.6m × 2.5m and a volume of 430m³. 3 Two fertilizer mixing tanks will be constructed, each measuring 3m × 6m × 2.5m with a volume of 90m³. 3 The mixing tank consists of three fiberglass tanks connected in series, each with a volume of 18m³. 3 The specifications of the clear water tank and fertilizer mixing tank above are for illustrative purposes only. Seedling growers may construct clear water tanks and fertilizer mixing tanks of other sizes according to actual conditions, which will not be elaborated here.

[0034] In addition, when building seedling sheds and seedling ponds, sanitation and disinfection facilities are usually constructed, and steps such as leveling the bottom of the ponds, dividing the seedling ponds, and laying weed control film are carried out. Since the above steps are technically mature and there are many solutions, they will not be elaborated here.

[0035] 2) Prepare multiple paper pots filled with substrate, sow tobacco seeds in the substrate, and place multiple paper pots in the seedling bed at intervals, leaving a 2cm-3cm gap between adjacent paper pots for adding water and fertilizer.

[0036] The paper pot tray (chain-type paper pot) consists of multiple hexagonal seedling holes, which are interconnected vertically. Adjacent seedling holes are connected by a connecting strip of equal length to the side of the seedling hole. During seedling cultivation, a certain number of seedling holes are folded in a row to form a rectangular structure. The substrate is filled into the seedling holes of the paper pot tray, and excess substrate on the surface of the paper pot tray is scraped off to ensure that each seedling hole is full of substrate. One to two coated seeds are sown in each seedling hole to a depth of less than 0.5 cm, and covered with 4 mm of substrate. Then the paper pot tray is placed in the seedbed. Before filling the seedling holes, the substrate needs to be mixed with water and the moisture content needs to be tested. The substrate should be able to clump together when squeezed but crumble easily when touched, ensuring that the initial moisture content of the substrate reaches 30%. The moisture content η of the substrate satisfies: η = (M0 - M1) / M1 × 100%, where M0 is the wet sample mass of the substrate and M1 is the dry sample mass of the substrate after drying.

[0037] 3) Water management: Add water to the seedling bed to bring the substrate moisture content to 70-80% until seedlings emerge. In other words, during the seedling emergence period when tobacco seeds break through the soil, add clean water to the seedling bed and let the paper pots absorb water until the substrate in the paper pots is completely moist. Add water intermittently by alternating between dry and wet conditions to ensure that the substrate moisture content reaches 70-80% so that the seeds can absorb water, swell, and emerge.

[0038] After the tobacco seeds in the substrate germinate, wait for the moisture in the substrate in the paper pot to evaporate naturally until the moisture content of the substrate is less than 55%. At this time, the tobacco seedlings are in a "dry" environment of alternating dry and wet conditions. Water the seedlings. After the moisture content of the substrate reaches 70-80%, that is, after the tobacco seedlings are in a "wet" environment of alternating dry and wet conditions, repeat the steps of waiting for the moisture in the substrate to evaporate naturally and then watering until the seedlings are transplanted.

[0039] Preferably, the moisture content of the substrate should generally be maintained above 50%, that is, when the substrate is in a "dry" environment of alternating wet and dry conditions, the moisture content of the substrate should be between 50-55% (including breaks).

[0040] 4) Fertilizer management: 8-12 days after sowing, when 70-80% of the seeds have emerged, apply the first top dressing of water-soluble fertilizer for tobacco seedling cultivation. After emergence, increase the concentration of water-soluble fertilizer in stages according to the development stage of the tobacco seedlings. During the seedling period, water and fertilizer management should be carried out by alternating between applying water-soluble fertilizer twice and adding water once.

[0041] The water-soluble fertilizer for tobacco seedlings contains nitrogen, phosphorus, and potassium in a ratio of 17:17:17. After two applications of fertilizer, a watering with clean water is performed to dissolve and rinse away residual fertilizer salts in the soil, preventing nutrient accumulation caused by continuous fertilization, and in accordance with the principle of alternating wet and dry water management in step 3.

[0042] 5) Temperature management: After sowing until emergence, maintain the temperature inside the greenhouse in the range of 20℃-28℃; after emergence until the large cross stage, maintain the temperature inside the greenhouse in the range of 22℃-30℃; after the large cross stage, maintain the temperature inside the greenhouse in the range of 25℃-30℃.

[0043] Nursery workers can use multiple temperature sensors pre-installed in the seed shed to monitor the temperature at different locations in the seedling trays in real time, enabling precise temperature control of multiple paper pots. Timely water replenishment offsets the effects of natural evaporation and indirectly regulates the ambient temperature around the substrate, creating a suitable temperature environment for the tobacco seedlings. As the seedlings grow and develop, timely temperature adjustments can simulate natural temperature conditions, further improving the seedlings' resistance to stress and environmental adaptability.

[0044] 6) Pest and disease control.

[0045] Understandably, timely watering is crucial during the seedling stage, from seed to seedling emergence. From emergence to transplanting, the management process involves alternating wet and dry periods, allowing the substrate moisture to evaporate naturally before watering again. This ensures the substrate moisture content reaches 70-80% throughout the seedling stage. By adjusting the substrate moisture content, the water supply to the substrate in the paper pots is precisely controlled, guaranteeing the seedlings are in a suitable wet-dry environment, promoting seed germination and seedling growth, as well as root development and enhancing the seedlings' resistance to adverse conditions.

[0046] Furthermore, water and fertilizer management under the premise of alternating wet and dry conditions can improve the continuity and consistency of tobacco seedling cultivation. It facilitates the control of substrate moisture supply in the paper trays by nursery workers, ensuring the development of tobacco seeds within the trays. Compared to traditional floating or tray cultivation, paper tray cultivation only requires maintaining the substrate moisture content and does not require a uniform water level in the seedbed. This significantly reduces the requirements for the bottom level, especially when cultivating multiple paper trays, thus reducing the workload of nursery workers. Moreover, since maintaining a level bottom is not necessary, a weed control sheet can be used instead of a membrane to prevent weeds and ensure seedling growth.

[0047] It should be noted that, in addition to using instruments (weighing devices and dryers) to measure the weight of substrate samples, at least one of the following methods can be used to determine whether the moisture content of the substrate is less than 5%: visual inspection, tactile inspection of the substrate surface, substrate weight comparison, and observation of tobacco seedling morphology. Specifically, ① Visual inspection: If visible water is observed at the bottom of the tray, and the substrate surface is not wet (whether the substrate surface is whitish or whether there is moisture reflecting off the substrate surface under direct morning sunlight), and the surface substrate is separated from the paper pots around the seedling holes, then the result is that the moisture content of the substrate is less than 55%, and watering is needed; otherwise, the result is that watering should be postponed. ② Tactile inspection of the substrate surface: Insert your fingertip into the substrate 1-2 If the substrate feels dry and loose, the moisture content is less than 55%, and watering is needed. Otherwise, watering should be postponed. ③ Substrate weight comparison: Hold the substrate (or a paper pot with substrate) by hand. If the substrate feels light and heavy, the moisture content is less than 55%, and watering is needed. Otherwise, watering should be postponed. ④ Observation of tobacco seedling morphology: Observe the leaves and roots of the tobacco seedlings. If the leaves show at least one of the following symptoms: wilting, curled edges, or dark green and dull color, the moisture content is less than 55%, and watering is needed. If the leaves turn yellow, or the roots turn brown or rot, watering should be postponed.

[0048] In addition to using the single method mentioned above to determine the moisture content of the substrate, users can also use multiple methods to make a comprehensive determination, further improving the accuracy of the results.

[0049] The watering volume M in the seedling bed satisfies: a×10.5ml×b≤M≤a×15.8ml×b, where a is the total number of tobacco seeds in each paper pot and b is the total number of paper pots.

[0050] Equivalent transformation of the above formula yields: 10.5ml ≤ M / (ab) ≤ 15.8ml. In other words, after watering the seedbed, the average watering amount per seedling in a single paper pot is 10.5ml–15.8ml (including the endpoints). Taking a single paper pot with 190 seedling holes as an example, the watering amount required for each paper pot is 2–3L, and the watering amount M for each seedbed is 2×b–3L×b.

[0051] By properly controlling the amount of water poured into the seedling bed, each tobacco seedling in a single paper pot can be watered in a timely manner, while avoiding excessive watering that could cause waterlogging or disperse fertilizer, thus ensuring the stable development of the tobacco seedlings.

[0052] In some embodiments, a pressurized sprinkler irrigation system is used to water the seedbed during water management operations.

[0053] For example, in this embodiment, a 1-meter pressurized sprinkler system is used. The spray arc of the 1-meter sprinkler covers an area of ​​about 8 square meters, and the water output is 4L per minute. One tray of seedlings (60.5cm long and 30.5cm wide) covers about 0.185 square meters. The 1-meter sprinkler can cover about 43 trays of seedlings, and each watering time is about 20 minutes.

[0054] By setting up a pressurized sprinkler system, nursery workers can accurately control the amount of water sprayed and the frequency of spraying, reducing water waste and improving water use efficiency. In addition, the pressurized sprinkler system is highly adaptable and can be adapted to various layouts of seedling beds and paper pots, making it convenient for nursery workers to set up and use.

[0055] In other embodiments, drip irrigation strips or Ф2.0-2.5cm plastic pipes are used to water the seedling beds during water management operations.

[0056] Using drip irrigation strips or Ф2.0-2.5cm plastic pipes to slowly add water by utilizing the elevation difference can keep the substrate moist without dispersing fertilizer, reduce water evaporation, extend the substrate's moisture retention time, optimize the tobacco seedling development environment, and the drip irrigation strips or plastic pipes are inexpensive, which can reduce the construction cost of the seedling shed.

[0057] Furthermore, in fertilization management: from the seedling stage to the large cross stage, water-soluble fertilizer should be added at a concentration of 100-150 ppm (180-200g of water-soluble fertilizer diluted in 200kg of water); after the large cross stage, water-soluble fertilizer should be added at a concentration of 200 ppm (220-250g of water-soluble fertilizer diluted in 200kg of water).

[0058] During the seedling emergence to the large cross stage, the root system of tobacco seedlings is relatively weak. Water-soluble fertilizer should be applied to the roots via irrigation or drip irrigation at a concentration of 100-150 ppm to ensure the absorption of nutrients such as nitrogen, phosphorus, and potassium while avoiding root burn caused by excessive fertilizer concentration. After the large cross stage, the tobacco seedlings enter a rapid growth period. The concentration of water-soluble fertilizer should be increased to increase the nitrogen, phosphorus, and potassium ratio and promote seedling growth. Increasing the concentration of water-soluble fertilizer in stages according to the seedling development stage meets the dynamic nutritional needs of the seedlings during the seedling period, achieving precise fertilization and significantly improving the growth efficiency and quality of the seedlings.

[0059] Understandably, when carrying out water and fertilizer management, water and fertilizer should be added 5-7 days after the bottom of the pond dries up, and water and fertilizer should be added again the day after the water dries up.

[0060] Fertilize again the day after the water has dried up to avoid excessive nutrient accumulation caused by continuous fertilization, reduce fertilizer waste and prevent seedling burn. It also makes it easier for seedling nursery workers to fertilize during their normal working hours, reducing their workload.

[0061] Understandably, during temperature management, watering should be done every 2-3 days. If the temperature inside the greenhouse is higher than the range that should be maintained, specifically, from sowing to emergence, if the average temperature inside the greenhouse or the temperature in some areas of the greenhouse is greater than 28℃, watering should be done every 1-2 days; from emergence to the large cross stage, if the average temperature inside the greenhouse or the temperature in some areas of the greenhouse is greater than 30℃, watering should be done every 1-2 days; after the large cross stage, if the average temperature inside the greenhouse or the temperature in some areas of the greenhouse is greater than 35℃, watering should be done every 1-2 days.

[0062] As temperatures rise, the rate of moisture evaporation in the substrate will increase. At this time, it is necessary to increase the watering frequency and replenish water in a timely manner to prevent the substrate from drying out too quickly and affecting the development of tobacco seedlings.

[0063] It should be noted that when tobacco seedlings are in an extremely high-temperature environment, that is, when the moisture content of the seedlings drops rapidly to 55% or below within one day, they can be watered daily to allow the moisture content of the seedlings to quickly rise back to 70-80%.

[0064] It should be added that on sunny days when the temperature is relatively high, the seedling shed can be opened with only the insect-proof netting left on for timely ventilation and cooling.

[0065] Understandably, in pest and disease control operations, one pest control is carried out before seedling emergence and another after entering the small cross stage, using high-chlorine emamectin benzoate insecticide, diluted 1500 times for spraying.

[0066] Furthermore, from the small cross stage to the large cross stage, use 0.5 kg of 50% phoxim emulsifiable concentrate mixed with 5 kg of water and 50 kg of bait to trap and kill ground beetles, crickets, mole crickets, and slugs.

[0067] Understandably, during the early stages of tobacco seedling growth, oligosaccharide-guanidine (for viral diseases), oligosaccharide-chain protein (75g / mu-100g / mu), and ningnanmycin (1200-1600 times dilution for viral diseases) are used for secondary prevention of viral diseases. Bacillus subtilis containing 100 billion Bacillus spores at a concentration of 5000 times is used to prevent "two black diseases" (a type of disease).

[0068] It should be noted that the water supply to the tobacco seedlings needs to be controlled one week before transplanting. Specifically, the seedling nursery staff should uncover the shade net to increase the amount of light. If the temperature is high on a sunny day, the seedlings can be uncovered all day. When the seedlings wilt, spray water with a spray bottle until all the leaves are moist. If it rains, cover the seedbed in time.

[0069] It should also be noted that when the seedlings are 35-40 days old, the tobacco seedlings have grown to four leaves and one bud, and the plant height is 7cm-10cm, they have reached the standard for transplanting tobacco seedlings under plastic film.

[0070] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for raising tobacco seedlings, characterized in that, Includes the following steps: 1) Construct seedling sheds and seedling ponds; 2) Prepare paper pots filled with substrate, sow tobacco seeds in the substrate, and place the paper pots into the seedling bed; 3) Water management: Add water to the seedling bed to bring the moisture content of the substrate to 70-80% until the seedlings emerge. Wait for the moisture in the substrate in the paper pot to evaporate naturally until the moisture content of the substrate is less than 55%. Water the seedling bed. After the moisture content of the substrate reaches 70-80%, repeat the steps of waiting for the moisture in the substrate to evaporate naturally and then watering until the seedlings are transplanted. 4) Fertilizer management: 8-12 days after sowing, when 70-80% of the seeds have emerged, apply the first top dressing of water-soluble fertilizer for tobacco seedling cultivation. After emergence, increase the concentration of the water-soluble fertilizer in stages according to the development stage of the tobacco seedlings. During the seedling period, water and fertilizer management should be carried out by alternating between applying water-soluble fertilizer twice and adding water once. 5) Temperature management: After sowing, control the temperature inside the greenhouse to be maintained in the range of 20℃-28℃; after emergence, control the temperature inside the greenhouse to be maintained in the range of 22℃-30℃; after the large cross stage, control the temperature inside the greenhouse to be maintained in the range of 25℃-30℃. 6) Pest and disease control; When carrying out water and fertilizer management, after adding water and fertilizer, take 5-7 days until the water at the bottom of the pond dries up as the standard, and then add water and fertilizer the day after the water dries up.

2. The method for raising tobacco seedlings according to claim 1, characterized in that, The watering volume M of the seedling bed satisfies: a×10.5 ml×b≤M≤a×15.8 ml×b, where a is the total number of tobacco seeds in each paper pot and b is the total number of paper pots.

3. The method for raising tobacco seedlings according to claim 2, characterized in that, In water management operations, a pressurized sprinkler irrigation system is used to water the seedling ponds.

4. The method for raising tobacco seedlings according to claim 2, characterized in that, In water management operations, drip irrigation strips or Ф2.0-2.5cm plastic pipes are used to water the seedling ponds.

5. The method for raising tobacco seedlings according to any one of claims 1-4, characterized in that, In fertilization management: from the seedling stage to the large cross stage, the water-soluble fertilizer is applied at a concentration of 100-150 ppm; after the large cross stage, the water-soluble fertilizer is applied at a concentration of 200 ppm.

6. The method for raising tobacco seedlings according to any one of claims 1-4, characterized in that, During temperature management, water every 2-3 days. If the temperature inside the greenhouse is higher than the range that should be maintained, water every 1-2 days.

7. The method for raising tobacco seedlings according to any one of claims 1-4, characterized in that, In pest and disease control, apply insect control once before seedling emergence and again after the seedlings enter the small cross stage. Use high-chlorine emamectin benzoate insecticide, diluted 1500 times for spraying.

8. The method for raising tobacco seedlings according to claim 7, characterized in that, From the minor cross stage to the major cross stage, use 0.5 kg of 50% phoxim emulsifiable concentrate mixed with 5 kg of water and 50 kg of bait to trap and kill ground beetles, crickets, mole crickets, and slugs.

9. The method for raising tobacco seedlings according to any one of claims 1-4, characterized in that, In pest and disease control operations, during the early stages of tobacco seedling growth, oligosaccharide-guanidine, oligosaccharide-chain protein, and ningnanmycin are used to prevent secondary viral diseases; Bacillus subtilis containing 100 billion Bacillus spores at a concentration of 5000 times is used to prevent "two black diseases".