Cultivation techniques of flue-cured tobacco

At present, there are two main ways to promote tobacco seedling raising: one is tray stubble in two-stage seedling raising; The second is floating seedling raising.

First, the tray heel in seedling raising.

The standard of a strong seedling: the seedling age is about 65 days, the number of leaves is about 9, the stem height is 8- 10 cm, the stem diameter is 0.5-0.6 cm, and it is tough, the leaves are green to light green, the leaves are thick, the lateral roots are developed, there are no pests and diseases, and the population is neat and consistent. The standard of strong seedlings varies according to different transplanting requirements. The stems of deep-planted tobacco seedlings and film-covered tobacco can be higher (10- 12 cm), and the stems of shallow-planted tobacco seedlings and film-covered tobacco can be shorter (6-8 cm).

2. Seedling facilities

Greenhouse (shed), seedling tray, film, etc.

Three disinfection

1. Disinfectant: montmorillonite (chemical name: sodium aminomethyl sulfide), potassium permanganate and formalin.

2. Disinfection of the mother bed: firstly, the green soil on the compartment surface is loose and flat, covered with nutrient soil, and the humidity is kept at about 70%. Then, 50 ml of montmorillonite water per square meter is diluted into 60 times solution and evenly sprinkled on the seedbed, then the greenhouse is sealed, and after 3-4 days, the topsoil on the compartment surface is raked off, and the residual medicine gas is fully volatilized for 4-5 days by ventilation.

3. Disinfection of seedling tray: Before use, spray the seedling tray with 1-2% formalin solution or 0.05-0. 1% potassium permanganate for disinfection, and then rinse it with clear water.

4, nutrient soil disinfection:

The fourth sowing

1, determine the sowing date: generally sow 80-85 days before transplanting.

2. Sowing amount: Sow 200-300g coated seeds per standard seedbed (10 m2).

Five-seedbed management

1, mother bed management

2. Subbed management

Second, floating seedling raising

Significance of floating seedling raising;

First, reduce pests and diseases.

Second: fast growth and even seedlings.

Third: save fertilizer and water.

Fourthly, it is beneficial to realize the specialization of seedling raising and the improvement of cultivated varieties.

Two advantages of floating seedling raising:

First, the neatness of tobacco seedlings is conducive to improving the uniformity and consistency of field production, thus improving the overall production level.

Second, the root system of tobacco seedlings is developed, and the number of roots is more than 1 times that of conventional seedlings, which is beneficial to improve the survival rate of transplanting.

Third, it can effectively overcome the phenomenon of early flowering.

Fourthly, soilless culture can effectively control soil-borne diseases, especially viral diseases.

Fifth, the seedling tray for seedling raising is light in weight and easy to transplant.

Section 3 Balanced Fertilization

Balanced fertilization is the fundamental measure to balance the internal components of tobacco leaves. Balanced fertilization refers to the total amount, structure, fertilizer type, time and method of fertilization in flue-cured tobacco production, which should be coordinated with the fertilizer demand characteristics of flue-cured tobacco growth and development and the fertilizer supply capacity of tobacco-growing soil.

Balanced fertilization must be based on soil testing in tobacco fields, with scientific formula and the relationship between water, fertilizer, gas and heat as the means to balance the chemical composition of tobacco leaves, improve the physical and chemical properties of soil and realize the sustainable development of tobacco production.

I. Characteristics of soil fertility in tobacco-growing areas of our county

In 200 1 year, shidian tobacco company collected 345 soil samples for analysis, and the results are as follows:

PH value: The most suitable PH value for flue-cured tobacco planting is 5.5-6.5, only 28.8% in Shidian tobacco field and 12.3% in 6.5-7.5 soil, and the sum of the two items is only 41.1%; And > 7.5% alkaline soil accounts for 47.9%; < 5.5% acid soil accounts for 1 1%, mainly distributed in Taihe township. Flue-cured tobacco likes weak acid soil and is alkaline, which is not suitable for the biological characteristics of flue-cured tobacco and also affects the decomposition of soil fertilizer. It may be related to the difficult growth and rapid development of flue-cured tobacco in the early stage, so attention should be paid to early fertilization.

Organic matter: 57.5% in soil sampling is high, which is related to continuous cropping of tobacco and rice and returning tobacco stems to the field. The average content in Shidian is 46.7, which is one thousandth higher than the provincial average 12.9.

N element: rich in content, related to the high content of soil organic matter, because more than 90% of soil N element comes from organic matter.

P element: Generally speaking, it is rich and related to the content of organic matter. Most of the soil P element comes from organic matter.

K element: the tobacco-growing areas in the province lack K, and Shidian is lower than the provincial level.

Second, the characteristics of fertilizer requirement of flue-cured tobacco

The normal growth and development of flue-cured tobacco requires more than ten kinds of nutrients. Macro elements are nitrogen, phosphorus and potassium, medium elements are carbon, hydrogen, oxygen, calcium, magnesium and sulfur, and trace elements are iron, manganese, boron, zinc, copper, molybdenum and chlorine.

According to the analysis of mature tobacco leaves by Tobacco Research Institute of Chinese Academy of Agricultural Sciences, it is known that nitrogen is the most in leaves, phosphorus in roots, stems and leaves is almost the same, and potassium in stems and roots is more. Potassium is the most in the whole plant, followed by nitrogen and phosphorus. Three. Some views on balanced fertilization in our county

Fertilization model

Firstly, the characteristics of soil nutrients in our county are summarized: the content of organic matter and total N is high, but the PH value is high, there is more rain in the early stage, the mineralization and release ability of organic matter is poor, and the available N element in the early stage is still insufficient; Phosphorus is rich, potassium is low, and boron deficiency is common. So our model should be: controlling N, stabilizing P and increasing K.

Distribution of two nutrients

Nutrient distribution is the distribution of base fertilizer and topdressing. The distribution principle is to pay more attention to base fertilizer than topdressing. 60% nitrogen, 100% phosphorus and 40% potassium as base fertilizer; 40% nitrogen and 60% potassium topdressing.

3. Fertilization amount per mu

Focus on the promotion of special base fertilizer+seedling fertilizer+potassium nitrate (or special topdressing)+potassium sulfate+foliar fertilizer fertilization model. Pig manure 15-20 parts and fireclay ash 15-20 parts are used as base fertilizer.

Mode 1: 60 kg special base fertilizer +7.5 kg special fertilizer for seedling +25 kg potassium nitrate+12.5 kg potassium sulfate;

Method 2: 60 kg special base fertilizer +7.5 kg special fertilizer for seedling +40 kg special topdressing+12.5 kg potassium sulfate;

Note: All stations with potassium nitrate inventory will run out of potassium nitrate inventory according to mode 1, and stations without potassium nitrate inventory will use chemical fertilizer according to mode 2.

Boron fertilizer, manganese fertilizer and magnesium fertilizer should be added to prepare special fertilizer. According to the growth of tobacco seedlings, foliar fertilizer mainly containing potassium can be sprayed in the later stage.

Fourth, the fertilization time.

Apply base fertilizer once before transplanting. Topdressing three times after transplanting, and applying potassium sulfate 1 time about 45 days after transplanting. It is very important to apply potassium fertilizer before and after topping, and spray foliar fertilizer mainly containing potassium when it is mature.

Five fertilization methods

1, base fertilizer

According to the practice in recent years, special attention should be paid to the following points when applying base fertilizer:

(1) 70kg of special base fertilizer must be applied per mu as base fertilizer, and no part of topdressing is allowed. ⑵ Deep furrow fertilizer or "1" furrow fertilizer should be applied deeply, about 30cm away from the ridge surface. If it is as deep as the hole fertilizer, or even shallower than the hole fertilizer, it will not play the role of deep application of chemical fertilizer, and it is easy to evaporate and lose, and the late growth stage of flue-cured tobacco will be premature due to lack of fertilizer, and even the upper leaves will not open. (3) The hole fertilizer must be well mixed with the soil, otherwise the roots of tobacco seedlings will be damaged by fertilizer, and the immortal seedlings will be delayed. ⑶ basal fertilizer (including hole fertilizer) should be applied early, preferably 20 days ~ 1 month before transplanting. In this way, the base fertilizer has a period of composting decomposition time in the soil, with high fertilizer efficiency and no fertilizer damage. 5] Farm manure (pig manure, fireclay ash) must be cured for more than 1 month, so that it can be fully cured to reduce the harm of germs, viruses and other substances to tobacco seedlings.

2. Surface treatment

The principle of top dressing of flue-cured tobacco in field: front foot, middle weight and later supplement. In the early field (the first month after transplanting), because the plants are mainly long roots, the fertilizer demand is less than that in the prosperous period, and the hole fertilizer is playing a role, so it is not appropriate to apply too much fertilizer. We call it seedling fertilizer, mainly nitrogen, which is limited to sufficiency. In the middle of the field (the second month after transplanting), the tobacco plants grow vigorously, and most of the stems and leaves (more than 70% of the harvested tobacco leaves) grow at this stage, and the amount of fertilizer required during the whole growth period is the most, so the top dressing is heavier at this stage, accounting for about 70% of the total top dressing.

Section 4 Plastic Film Mulching Cultivation

Cover film should pay attention to the following points:

First of all, soil wetting is the premise of plastic film mulching. The water content should be above 80%. If the water content is low, it will not rain in the future, and the tobacco seedlings will be dry after transplanting. Moreover, the lack of soil moisture is not conducive to the decomposition of base fertilizer, and it is easy to cause root burning or even seedling death.

Second, the film covering time. Cultivation under plastic film must be planted and covered immediately. In 2008, in some places, tobacco seedlings were not covered on the same day after planting, and frosted at night, which damaged many tobacco seedlings. In film cultivation, the film can be covered 10 days to one month in advance. As long as the soil is wet, apply base fertilizer and chemical herbicide, you can cover the film. Pay attention to the safety period (5-7 days) when applying herbicides, and you can only grow cigarettes after the safety period. Before film mulching, you can spray daily high-grade pesticides to reduce pests.

Third, the requirements for covering film. The general requirements are: flat, straight, tight and dense, so that the wind can't blow, and the effect of heat preservation, water conservation and fertilizer conservation can be truly achieved.

Fourth, uncover the film. After the tobacco plants are clustered, or transplanted for about 35 days, or the temperature is stable above 65438 08℃ for more than 5 consecutive days, the film can be uncovered, and the film must be uncovered. Some tobacco farmers advocate not uncovering the film, which is wrong.

Verb (abbreviation of verb) Application of chemical herbicides. At present, the herbicides used are pre-seedling herbicides and post-seedling herbicides. Pre-bud herbicides such as Jinduer must be sprayed before film mulching. It is worth noting that the soil must be broken and leveled before spraying; Cover the film immediately after spraying, and don't destroy the film, otherwise the efficacy will be reduced; When spraying, the soil is wet, the water content is too small, the liquid medicine can't seep down, and the drug effect can't be exerted, but the water content is too high, the liquid medicine is too deep, and it can't be volatilized. In the future, the root tips of tobacco roots are vulnerable to drug damage, leading to delayed growth or dead seedlings. When spraying herbicides after germination, such as roundup, it should be sprayed on weed leaves (absorbed by leaves) as far as possible, and the spraying time should be at least 10 days before transplanting to avoid tobacco leaf injury.