1. Establish an agricultural system based on tobacco. Crop rotation is an important part of crop planting system, and it is an effective measure to combine land use with farming to increase the yield of tobacco leaves and crops and improve the quality of tobacco leaves. Establish a tobacco-based farming system, scientifically and reasonably arrange crop species and planting order in the rotation cycle; Make tobacco production gradually enter a stable, sustained and healthy development of the virtuous circle track. Reflect "tobacco-oriented, balanced development; Combining nutrition with farming to improve soil fertility; Purify soil and reduce diseases; Raise cigarettes with cigarettes and continue to develop. "
2. Increase the application of bio-organic fertilizer and decomposed farmyard manure. Bio-organic fertilizer is an organic fertilizer made of organic solid waste (including organic garbage, straw, human, livestock, poultry manure, cake, agricultural and sideline products and food processing) through microbial fermentation, deodorization and complete decomposition. Rich in functional microorganisms and trace elements, it can improve soil structure, indirectly kill ascaris eggs and root nematodes, play a role in nutrition, conditioning and health care for crop growth, and make the land absorb organic matter to play a greater role.
Bio-organic fertilizer is a nutrient storage pool with complete nutrients, which is compatible with quick-acting nutrients and slow-acting nutrients, organic nutrients and inorganic nutrients, and can improve soil and soil hardening caused by using chemical fertilizers. Improve soil physical and chemical properties, improve soil porosity, permeability and exchangeability, and enhance soil water and fertilizer conservation capacity. Beneficial microorganisms in bio-organic fertilizer enter the soil, forming a relationship of mutual growth and proliferation with microorganisms in the soil, inhibiting the growth of harmful bacteria, transforming them into beneficial bacteria, interacting and promoting each other, and playing a synergistic role in the population. Beneficial bacteria produce a large number of metabolites in the process of growth and reproduction, which can promote the decomposition and transformation of organic matter, directly or indirectly provide crops with a variety of nutrients and stimulating substances, and promote and regulate crop growth. At the same time, the dominant beneficial flora formed in the root system of crops can inhibit the reproduction of harmful bacteria, enhance the resistance and disease resistance of crops, reduce the disease index of continuous cropping crops, and greatly alleviate the obstacles of continuous cropping after years of application.
Rotten farmyard manure refers to various organic substances such as human manure and livestock manure, which can be used as fertilizer after stacking and decomposition. Rotten farmyard manure contains all kinds of nutrients and rich organic matter needed by crops, which is conducive to promoting the formation of soil aggregate structure, coordinating the proportion of gas and water in soil, providing energy and nutrients for microbial life activities, promoting the activities of soil microorganisms, loosening soil, and increasing the ability of water retention, heat preservation, ventilation and fertilizer conservation. Comprehensive nutrition and long-lasting fertilizer effect. Tobacco production practice has proved that reasonable and correct application of farm manure can effectively improve soil physical and chemical properties, promote soil microbial activity and activate soil potential nutrients, which plays an important role in improving soil fertility, improving soil, increasing tobacco yield, improving tobacco quality and increasing tobacco aroma and quality.
3. Vigorously promote straw returning technology. Straw returning to field is a method of applying straw (corn straw, sorghum straw, etc.). ) it is not suitable for direct feeding or direct feeding after accumulation and decomposition in soil. Crop straw is an important resource of organic fertilizer. Returning straw to field is of great significance to ensure sustainable agricultural growth, improve soil fertility, maintain soil organic matter balance, supplement soil potassium, increase soil nutrient content, improve soil physical properties, increase soil microbial population, optimize farmland ecological environment, reduce soil moisture evaporation, maintain surface soil water storage capacity, and alleviate soil erosion caused by surface runoff during rainfall, which is conducive to improving precipitation utilization rate and drought resistance.
Returning straw to the field not only increases the content of soil organic matter and nutrients, but also improves the physical properties of soil and enhances the permeability of soil. Humus is a soil structure colloid formed by decomposition of straw after returning to the field, which is beneficial to the formation of soil aggregate structure, good soil permeability, increase soil fertility and water retention capacity, reduce soil bulk density, increase porosity and soil water content, and is beneficial to crop drought resistance. Returning straw to the field year after year can reduce the amount of chemical fertilizer and production cost. The production practice shows that the application of straw has a significant effect on improving soil structure, and the application of gramineous straw can improve soil permeability, adjust nitrogen nutrition of flue-cured tobacco, make nitrate nitrogen in flue-cured tobacco high before and low after, and then improve tobacco quality.
4. Develop green manure for vetch seeds to suppress green. Practice has proved that green manure is a good organic fertilizer. Reasonable application has obvious effects in increasing fertilizer sources, reducing the input cost of tobacco farmers, improving soil and fertility, and improving tobacco yield and quality.
Green manure has complete nutrients and contains nutrients and organic matter needed by crops such as nitrogen, phosphorus and potassium. It is a bio-organic fertilizer for improving soil and fertility, the key to increase crop yield, improve quality and maintain fertility, and also a high-quality feed for developing animal husbandry.
Green manure can cover the ground, reduce the bare farmland, alleviate soil erosion, reduce soil erosion, increase atmospheric humidity, alleviate atmospheric drought, improve field ecology, prevent crust after rainfall and reduce surface runoff. Planting green manure can also inhibit the growth of weeds in cultivated land, avoid the consumption of water and nutrients, create good conditions for agricultural production, make crops grow healthily and effectively improve the agricultural ecological environment. Planting green manure can reduce the amount of chemical fertilizer and greatly reduce the production cost.
After turning into the soil, the green manure is continuously decomposed under the action of microorganisms, which not only releases a lot of effective nutrients, but also forms humus. The combination of humus and calcium can cement soil and make soil particles agglomerate to form aggregate structure. The soil with aggregate structure is loose, porosity increases, bulk density decreases, air permeability is good, water and fertilizer retention is strong, and it has good gas and heat properties of water and fertilizer adjustment, which is beneficial to the growth and development of tobacco plants. At the same time, after green manure is applied to the soil, fresh organic energy substances are added, so that microorganisms can multiply rapidly, their activity is enhanced, the formation of humus and the availability of nutrients are promoted, and soil maturation is accelerated. Balanced fertilization
Excessive nitrogen fertilizer is the main reason for the high nicotine content and poor usability of upper leaves of flue-cured tobacco, especially after topping, the soil continues to maintain a high nitrogen supply. Therefore, it is very important to control the amount of nitrogen supply in the late stage of soil to improve the quality of upper leaves of flue-cured tobacco. Secondly, the form of nitrogen fertilizer has a direct impact on the availability of upper leaves. Nitrate nitrogen can control nitrogen supply at maturity and inhibit nicotine synthesis caused by excessive nitrogen at later stage. To improve the quality and availability of upper leaves of flue-cured tobacco, the balanced application of phosphorus, potassium fertilizer and medium and trace elements should not be ignored. Phosphate fertilizer can not only promote the early growth and rapid growth of tobacco plants, but also increase the reducing sugar content of upper flue-cured tobacco leaves, reduce the starch content of tobacco leaves and improve the aroma and taste of tobacco leaves. The increase of potassium level can effectively promote the full maturity, substance transformation and dry matter accumulation of upper leaves of flue-cured tobacco, reduce harmful components, make the sugar-alkali ratio moderate and improve the quality of cigarettes. Therefore, it is necessary to formulate a formula fertilization scheme according to soil fertility, flue-cured tobacco varieties and ecological environment. Balanced fertilization and precise fertilization are the guarantee to improve the effectiveness of upper leaves of flue-cured tobacco.
Rational cultivation, scientific topping and leaf retention
Reasonable planting density can improve the light conditions of tobacco plants and promote the coordinated development of carbon and nitrogen metabolism in different parts of tobacco leaves, which is the basis for producing high-quality upper leaves. When the planting density is too small, the total available leaves are too few, and too many nutrients are distributed to a single tobacco plant, resulting in thicker upper leaves and higher nicotine. Row spacing 1 10- 120 cm, plant spacing of 50-55 cm, transplanting 1 100- 1200 plants /667m2, the nicotine content in upper leaves is suitable. The distribution and utilization of substances related to the number of leaves left are negatively correlated with the nicotine content of tobacco leaves. Increasing the number of leaves left and delaying topping can reduce the nicotine content in upper leaves and increase the sugar-alkali ratio. The number of leaves and topping period should be determined according to soil fertility, fertilization level and tobacco plant growth in production. It is necessary to prevent the formation of "umbrella-shaped" tobacco plants due to premature topping and excessive upper leaves, and to prevent the formation of "waist-drum-shaped" tobacco plants due to late topping and insufficient nutrition of upper leaves. Under normal water and fertilizer conditions, it is appropriate to leave 16- 18 leaves per plant, and top it when the bud or the first central flower opens; Under the condition of low fertilizer, appropriately reduce the number of leaves left and topping in advance, and use appropriate foliar fertilizer; Under high fertilizer conditions, increase the number of leaves and delay topping.
Scientific experiments show that topping too early or too late will increase total alkaloids and total nitrogen in tobacco leaves, and will increase tar content and total alkaloids in cigarette smoke; However, the number of leaves left affects the distribution and utilization of substances, which is negatively correlated with nicotine content. Therefore, according to the characteristics of different varieties and soil fertility, the reasonable topping time and the number of leaves left should be determined to ensure that the top leaves can be fully opened. In production, the method of secondary topping can be used to leave more leaves properly, so as to dilute the higher dry matter content in the upper part, reduce the nicotine and tar content, solve the problem of excessive thickness of the upper leaves and improve the usability of tobacco leaves. Under the condition of reasonable leaves, we are determined to solve the problem of insufficient maturity at present, and harvest according to different qualities, different parts and different maturity standards.
Improve maturity
The maturity of tobacco leaves in the field is closely related to the quality of upper leaves of flue-cured tobacco. With the increase of maturity of upper leaves, the structure of upper leaves became looser, the contents of total sugar and reducing sugar increased obviously, the quality and quantity of aroma increased, and nicotine gradually decomposed. The upper leaves are harvested when the main color of tobacco leaves is yellow, the leaves have obvious mature spots, and the main veins turn white and shiny. The immature upper leaves are thick and hard after baking, and it is easy to appear bluish black when baking, which leads to a serious decline in the quality and usability of the upper leaves. Optimize cultivation techniques and comprehensively implement agricultural technical measures to improve the availability of tobacco leaves.
1. Breeding and popularizing flue-cured tobacco varieties with low tar, low potassium and high efficiency. At present, some flue-cured tobacco varieties with low tar release have been cultivated by various breeding methods in the world and have been popularized in production. On the basis of maintaining the original quality and style of tobacco leaves, new tobacco varieties with high potassium, low tar and low nicotine were screened, cultivated and planted with the main goal of reducing the tar and nicotine content of tobacco leaves and improving the potassium content and safety.
2. Vigorously promote balanced fertilization technology and strive to improve the inherent quality of tobacco leaves. Fertilization is the core technology of tobacco production, and the level of fertilization directly affects the quality of tobacco leaves. Pay attention to increase cake fertilizer and bio-organic fertilizer, balance nitrogen, phosphorus and potassium nutrition, and add trace elements such as zinc, boron and copper to coordinate soil nutrition. At the same time, in tobacco-growing areas, we should start with large-scale agriculture, strictly control the application of chlorine-containing fertilizers, especially prohibit the use of chlorine-containing compound fertilizers for tobacco leaves. In addition, in order to improve the potassium content of tobacco leaves and the utilization rate of potassium fertilizer. In order to reduce the fixation of potassium, the method of reasonable potassium application by stages can be adopted to improve the physical and chemical properties of soil and maintain the appropriate soil water content. By increasing the potassium content in tobacco leaves, the tar content and nicotine content in flue gas can be reduced, thus improving the usability of tobacco leaves. Proper curing can not only improve the appearance quality of tobacco leaves, but also effectively improve the internal chemical composition. Therefore, suitable baking environment is also an important factor to improve the usability of upper leaves. Flue-cured tobacco has thick upper leaves, compact structure, low water content and high content of macromolecular organic substances such as starch and protein. Therefore, the yellowing period should be appropriately extended during curing, so that the tobacco leaves can be fully yellowed and the substances in the tobacco leaves can be transformed in a coordinated and favorable direction, thus improving the usability of the tobacco leaves. For the upper leaves that are easy to bake, the baking strategy of "turning yellow at low temperature and low humidity and dragging with warm fire" should be adopted. For the upper leaves that are easy to hang ash, the baking strategy of "turning yellow at low temperature and low humidity, dehydrating and fixing color at low temperature" should be adopted. In addition, semi-drying and semi-curing can also improve the quality of upper leaves of flue-cured tobacco, reduce starch content, improve the coordination of chemical components, shorten curing time, reduce fuel consumption and reduce costs.
Adopting three-stage curing process, paying attention to ventilation and dehumidification, and popularizing heat exchange intensive curing barn where conditions permit, can effectively control the formation and accumulation of toxic nitrosamine compounds (TSNA) in the curing process and improve the safety of tobacco leaves.
First of all, we must strictly classify and weave cigarettes. Firstly, the collected tobacco leaves are classified and stacked according to their position, size and maturity, and then the representative tobacco leaves (size or maturity) are sorted out first. However, in the process of tobacco weaving, mature (lobular) and slightly poor (big leaf) tobacco leaves should be eliminated, and over-ripe leaves, seriously ill leaves, raw leaves and black exploded leaves with no baking value should be discarded. After that, the tobacco leaves are woven according to the order of good maturity or slightly poor maturity, and at the same time, different types of available tobacco leaves and tobacco leaves without baking value must be eliminated. Tobacco weaving should be homogeneous with the same stem, with the same maturity, uniform density in the stem and similar weight between the stems. Secondly, we should pack cigarettes scientifically. Counting the number of sticks before tobacco filling, according to the principle that the number of sticks in each layer is the same, the same layer is uniform, and the yellow leaves dry first, the tobacco filling sequence and the corresponding tobacco filling sequence are distributed, so as to realize the docking of tobacco baking characteristics and the temperature and humidity distribution law of the curing barn, and improve the baking quality of tobacco leaves in each layer. Generally speaking, the top temperature is high, the relative temperature is low, the tobacco leaves are dried first, the bottom temperature is the lowest, and the relative humidity is the highest. The tobacco leaves are finally dried, and the green leaves should try not to put yellow leaves. On the other hand, the updraft bulk curing barn has the characteristics of high bottom temperature and low relative humidity. Tobacco leaves are dried first, and yellow leaves are the main ones when they are packed. The top temperature is the lowest, the relative humidity is the highest, and the tobacco leaves are finally dried. It is necessary to ensure that tobacco leaves are raw and do not turn yellow. The temperature and humidity before and after depends on the age when the intensive baking room was built. In the process of tobacco weaving and filling, we should handle with care to prevent tobacco leaves from being damaged and blocked and reduce the quality of tobacco leaves. When transporting and stacking tobacco leaves, it is necessary to prevent exposure and over-extrusion, and minimize acts that damage the quality of tobacco leaves, such as scratches, abrasions, breakage and burns. Thirdly, we should master the skills of dehumidification and solve the problems of baking green, hanging ash and baking bad. Control the suitable drying degree of tobacco leaves. Accurately grasp the drying degree of tobacco leaves in the curing process, so that the curing stage can be steadily advanced. Tobacco leaf drying target: the leaf tip begins to turn yellow and the leaf body is hot and soft; 70% to 80% of tobacco leaves become Huang Shi, and tobacco leaves are basically dragged (if you can't reach the hook tip, it will be easy to bake green); The tobacco leaves are all in Huangshi, and the tobacco leaves are all dragged. Before the dry bulb temperature exceeds 43℃, the drying degree of tobacco leaves must reach curling, when the dry bulb temperature exceeds 46℃, the drying degree of tobacco leaves should reach more than half, when the dry bulb temperature exceeds 50℃, the leaf color must be basically fixed, and when the dry bulb temperature exceeds 55℃, all tobacco leaves should be fixed. Otherwise, it is easy to burn tobacco leaves (light is hanging ash, heavy is bad).