How to raise seedlings and how to manage tobacco?

How to raise seedlings and how to manage tobacco? Seedling transplanting is a tobacco cultivation method widely used all over the world. In the cultivation of tobacco in China, except for a small number of yellow flower tobacco and sun-cured tobacco, the vast number of tobacco areas are seedlings and transplanting. The basic requirement of raising seedlings is to produce strong seedlings with sufficient quantity and suitable size in time. General spring tobacco requires suitable strong seedlings, stalk stout, about 7 cm high, 0.7 cm in diameter, with 8-10 true leaves, no diseases and insect pests, normal growth and development, seedling age 50-60 days, well-developed root system, dark green leaves, strong stress resistance. 1. Seedling raising method (1) raising seedlings in open field: generally raising seedlings in warm season, the form can be divided into flat bed, high bed and sunny bed. ① flat border: the border is equal to or slightly higher than the ground, with ridges around the border, which are easy to irrigate and manage. It is widely used in the plain areas of Shandong, Henan and southern tobacco areas. ② high border: drains are made around the border to facilitate the discharge of stagnant water in the border and increase the soil temperature of the border, which is the main way to raise seedlings in plain areas with high groundwater level and paddy fields. ③ Yang bed: make a wind barrier on the north side of the border to protect against the wind and cold. Generally use sorghum straw, corn straw, or rice straw, wheat straw and so on as wall materials. According to the experiment, the temperature of sunny border was 3 ℃ higher than that of flat border, and the seedling stage was 10 days earlier. (2) Seedling raising in hotbed: it has the function of increasing temperature and heat preservation, preventing wind and moisturizing, and can sow and raise seedlings in frost period. It is widely used in northeast tobacco areas with short frost-free period. According to the specifications of the hotbed, the northeast tobacco area generally has a bed length of 10 to 12 meters and a width of 1.7 to 2.0 meters, and the bed frame is mostly made of wood and sorghum straw. Soil is used around the bottom of the frame. Dig the bed to a depth of 20cm to 25cm and fill it with fermented heat and nutrient soil. Brewing heat is often used with chopped corn stalks, fallen leaves, rice straw and fresh mule horse dung, with a steady thickness of about 6 cm. Nutritious soil is generally made of 50% fertile soil, 30% rotten barnyard manure and 20% fallen leaves of rotten fine straw. (3) Seedling raising in plastic greenhouse: artificial heating in greenhouse, sowing in hotbed and pseudo-planting of seedlings. The building specification of plastic greenhouse, according to the experience of Yanbian, Jilin Province, is suitable for moderate size, too much material, easy to be damaged by wind and easy to snow; if it is too small, it will heat up quickly during the day and cool down quickly at night, which is disadvantageous to heat preservation. Generally, it is not less than 60 square meters. The middle is 2-2.5 meters from the ground, 1.5 meters high on both sides, showing an arch. After the plastic film is laid, it is reinforced with hemp rope, and the distance between the ropes is 50 to 70 centimeters. A fire pipe is arranged in the shed, and a large furnace is built at one end of the shed. The sowing hotbed is the same as the pseudo-planting hotbed. 2. Sowing (1) seed treatment: including seed disinfection and seed soaking to accelerate germination. ① seed disinfection: it can eliminate anthracnose and various pathogens attached to the seed coat and achieve the effect of disease prevention and seedling protection. The commonly used agents are 2% formalin solution, 0.1% silver nitrate solution, 1% copper sulfate solution and 0.5% mercury solution. Put the seeds in a clean white cloth bag, put them in any of the above solutions, soak them for 10-15 minutes and take them out, rinse the solution clean for soaking and accelerating germination or dry sowing. ② seed soaking and sprouting: use a clean small white cloth bag, each bag contains about 500g seeds, the number of seeds should not exceed 1x2 of the volume of the bag, in case of sprouting, full and squeezed. After bagging, rub the seeds in water, scrub until dripping and the color becomes lighter. Soak the seeds after rubbing the seeds, and the suitable water temperature for soaking seeds is about 20 ℃. After soaking for 8 hours and 10 hours, the residual water was filtered and put under the condition of 20: 25 ℃. It is best to rinse once a day and control the excess moisture after washing. After about 5 days, the seeds were sown when the radicle length was equal to the seed length. The emergence period of bud sowing is shorter and the emergence is neat than that of direct seeding. It is widely used in spring tobacco areas in China. (2) sowing: the key to whether the sowing quality can produce strong seedlings at the right time must be sown at the right time according to local conditions. There are great differences in climatic conditions in different tobacco areas in China, and there are also great differences in sowing date and cultivation system. Only flue-cured tobacco can be divided into four categories: spring tobacco, summer tobacco, autumn tobacco, winter tobacco, non-spring and non-summer wheat field tobacco and so on. The sowing date is determined by the transplanting date. In general, the sowing time of spring tobacco and summer tobacco is 60-70 days before transplanting, and that of autumn tobacco and winter tobacco is about 50 days before transplanting. The sowing date in Hunan Province is January. The sowing rate is mainly determined according to the seed germination rate, sowing mode and seedling raising method. Use 3 to 5 grams for every 10 square meters (net area) when sowing. The amount of seed used in strip broadcasting and on-demand is small. When raising seedlings with plastic film insulation, watering in the early stage of the seedling bed is very inconvenient, and it is not conducive to heat preservation, so we must pour enough bottom water before sowing. Sowing should be uniform and should be covered after sowing. Fine sand, fine soil, straw, loose hair and pig manure can be used. Should be suitable thickness, uniform, spring tobacco bud sowing, should be covered with plastic film on the same day, tightly pressed with soil around. The highest point of the film is about 40 cm away from the border surface. 3. Seedling stage management (1) Protection at seedling stage: the seedlings in the early stage of seedling bed are tender and small, the resistance to stress is poor, and they are vulnerable to low temperature freezing. Heat preservation, moisture protection, hail prevention, hail prevention and frost prevention are the key measures in the early stage of seedling cultivation. The film must be sealed after sowing spring tobacco. Only by keeping the temperature and moisture in the bed can seedlings emerge quickly. After 2 true leaves of the seedlings, ventilation and dehumidification should be carried out as the temperature rises, otherwise, the seedlings are prone to burn, spots or patches. At this time, sunny days are generally from 8: 9 a.m. to 4: 5 p.m., the two ends of the film are ventilated, and the temperature is controlled within 35 ℃. During the period of 4 true leaves of the seedlings, the time of ventilation and dehumidification should be prolonged. If the temperature continues to rise after opening the two ends, the vents should be enlarged. Tobacco seedlings erect leaf stage, open both ends in the morning and afternoon, and uncover one side of the film at noon, and combine to refine the seedlings. (2) watering: the seedlings are covered with thin film and watered with sufficient soil moisture before sowing, no watering is needed in the seedling stage. When raising seedlings in the open air without film mulching, water should be sprinkled day by day or every other day during seedling emergence, so that the soil is always in a moist and soft state. During the "ten" period, the number of sprinkling water can be appropriately reduced, and the amount of water sprinkled can be appropriately increased. After the erect leaf stage, watering or appropriate border irrigation should be carried out according to the size of tobacco seedlings and soil moisture. In the seedling stage, it is usually based on the principle of no drought and no watering, so as to improve the resistance of tobacco seedlings. Rain Water more areas should pay attention to timely drainage, the whole seedling process, the seedbed must not have stagnant water phenomenon. (3) fertilization: fertilization in seedling bed is mainly based on base fertilizer and supplemented by topdressing. The amount of base fertilizer should meet the needs before the third true leaf stage, otherwise the base fertilizer is insufficient. Topdressing should be applied according to the growth status of tobacco seedlings, either 1 or 3 times. When the base fertilizer is sufficient, you can not pursue it. If topdressing is needed, compound fertilizer is the best. Before the emergence of the third true leaf, it is the most sensitive to ammonia nitrogen, so topdressing must be careful. The amount of nitrogen fertilizer should be 5: 10 grams per square meter. Do not use too much nitrogen fertilizer. After spraying chemical fertilizer, the tobacco seedlings must be washed with clean water to prevent fertilizer damage. (4) weeding among seedlings: it is an indispensable measure to cultivate strong seedlings. The seedlings were divided into 3 times when 3, 4 and 5 true leaves appeared, and the seedlings were fixed at the last time. The distance between seedlings is usually 6-8 cm. Timely weeding is conducive to nursery bed ventilation and control of diseases and insect pests, reducing fertilizer and water waste, usually weeding combined with seedlings. (5) pinching leaves: it is a strong and powerful measure to promote tobacco seedlings. Including three methods: timely removal of the lower Verticillium wilt leaves and leaves with yellow and green leaves with small physiological functions, and pinch off some leaves with exuberant physiological functions in the upper part. Leaf pinching is beneficial to ventilation and light transmission, and can restrain the growth rate of tobacco seedlings, which is an effective measure to regulate the consistent growth of tobacco seedlings and prevent overgrowth in the later stage. (6) timely prevention and control of diseases and insect pests: the main diseases at the seedling stage are anthracnose, quenching, etc., of which anthracnose is the most common. After the tobacco seedling has 4 or 5 true leaves, 1 ∶ 1 ∶ Bordeaux solution can be sprayed twice, or 50% Dysen zinc 500 times. The main pests in seedling stage are ground tiger, mole cricket, slug and so on. The more common harm is the ground tiger, where adults can be trapped and killed by light or poison bait (0.5 kg of 90% trichlorfon, 20 kg of water, 40 kg of fried wheat bran, sown in the field in the evening), and pesticides can be used to treat the soil in serious areas. 30% trichlorfon powder 2.5 kg per mu mixed into the soil. When slugs occur, they are sprinkled with lime powder near tobacco seedlings in the evening, or sprayed with 1 ∶ 100 rapeseed cake in the morning and evening. Click to get more tobacco planting techniques click to get more flower planting techniques