Tobacoo

1. Tobacco

2. Economic Importance • Tobacco (Nicotiana spp.) is an important cash crop. It is raised for its leaves which are used as cured product. • It is smoked as pipe, cigar, cigarette or hookah, and also used as snuff (powdered tobacco that is sniffed up the nostril rather than smoked) or chewed as a liquid in various forms. • The production, processing and selling of tobacco can increase the national revenue as well as earn foreign currency. Besides, it also provides an employment to the people as in its cultivation, curing, grading, factories and cottage industries. • It also produces nicotine sulphate which is used as an insecticide.

3. Tobacco seed contains 35-38% nicotine free oil. It is used in making soap and colors. • Its cake is used as a cattle feed. Cake contains 3% N, 30-35% crude protein and 20-27% carbohydrates. • Some species of tobacco are also utilized as an ornamental plant. • The most important constituents in tobacco leaves are the alkaloid nicotine, nicotianin, nicotinine and nicoteline. • The burning of tobacco leaves decomposes nicotine into pyridine, furfurol, collidine, hydrocyanic acid and carbon monoxide etc. The poisonous effects of tobacco are due to these substances of decomposed nicotine. • Tar is the total particulate matter, it consists of 1150 elements and 80 of them are carcinogenic.

4. There are about 4700 compounds in the smoke of tobacco, among them 200 are poisonous and more than 50 are carcinogenic. • The first harmful component in smoke is tar which plasters the respiratory tract. • Second important compound is carbon monoxide which lowers the blood level so enters into the blood and change the oxy-hemoglobin to carbonoxy-hemoglobin and create difficulty in breathing. • The third important component is Nicotene, which produces excess of adrenal hormone which could lead to heart attack, brain hemorrhage and paralysis of brain. • In Nepal, 39% male and 23% females smoke tobacco. About 15,000 people are dying each year due to smoking.

5. Distribution and Production • Tobacco is though believed to be originated from America, but there are contradictions and no clarity about its place of origin. • It was cultivated by the Red Indians at the time of discovery of America by Christopher Columbus in 1492. • He and his men on landing in the little island of Tobaga were greatly surprised to find the natives smoking tobacco. • In addition to smoking tobacco, the natives used to grind the leaves into a fine powder, or snuff, and inhaled it through a hollow cane tube called ‘tobago’. The name tobacco is derived from the word ‘tobago’.

6. Tobacco was taken to Europe by the Spaniards in 1559. The French Ambassador in Portugal Jean Nicota saw tobacco in Lisbon and he introduced it in France. • The scientific name Nicotina and the word nicotine are derived from his name. • In India, tobacco was introduced by Portuguese during 1605 and was used as hookah tobacco and cigarette/pipe tobacco since 1616 and 1711 respectively. • In Nepal tobacco was introduced in 17th century from India and commonly cultivated in terai regions. • Tobacco is cultivated globally on 3.93 m ha. With a total production of 6.9 million ton. • China, Brazil, India and USA are major producers of tobacco. These counties produce 67% of world’s tobacco.

7. Top Tobacco Producers (2017)

8. China is global leader, producing 40% of world’s total tobacco while Brazil is world’s top exporter owing 27% of world’s market by value. • The United States is the second leading exporter with 10.5% of the world’s market. • In 2014, Nepal produced 2329 metric tons of tobacco produced while the production declined to 602 metric tons in 2017. Tobacco growing is only a small fraction of agriculture in Nepal, covering only 372 ha (in 2017) in central and eastern terai. • As the country became a Party to the WHO Framework Convention on Tobacco Control on February 5, 2007, Government of Nepal do not invest on research and extension for tobacco production.

9. Morphology and Classification • Tobacco belongs to solanaceaefamily. It is a herbaceous annual crop grown primarily for its leaves. • Tobacco plant generally forms a shallow branched root system. • It has central tap root from which numerous short lateral roots extend. The majority of the root system is confined to 60-90 cm of the soil. • It has a simple cylindrical stem. The height of the plant and length of internodes vary in different types. • Of the two species, N. rustica is shorter and more robust and densely growing plant than N. tabacum.

10. The leaves vary to a great extent in number, shape and texture. • The stem is terminate in a raceme type of inflorescence which may have more 150 individual flowers. • The corolla contain five petals which are fused into a long tube and which terminate in five expanded lobes at the tip. • The flower bears the five anther which are fused to corolla tube. The pistil is compound and matures into a capsule fruit. • Tobacco is normally a self fertilized crop, but cross fertilization as much as 4-10% may occur from the pollen carried by insects. • The seeds of tobacco are extremely small, a single fruit may contain as many as 8000 seeds.

11. N. tabacum: • Usually the plants of this species are taller (150-180 cm). • The leaves are broad ovate to linear or lanceolate. These are commonly sessile but may be petiolate also. • Texture of leaves is finer and nicotine content ranges from 0.5-5%. • The color of flower is reddish, pinkish or white. • It requires medium type climate and have longer duration. • It is also used in the manufacture of cigarettes, cigar, cheroot and bidi purposes.

12. N. tabaccum N. rustica

13. N. rustica: • The plants of this species are stocky, more bushy in nature and shorter in height (90-120 cm). • The leaves are large and broad and ovate in shape and always possess a petiole. • Leaves are leathery and tough with higher nicotine content ranging from 3.5-8%. • Flowers occur in clusters and are of dull greenish-yellow colour. • It requires cooler climate and have short duration • It is used extensively for hookah, snuff and chewing purposes.

14. Based on ecotypes tobacco are classified as: • Oriental Type • High quality tobacco with low nicotine (up to 1.5%) and higher content of aromatic substances and sugar. • Good burning quality. • 2 type of varieties (Macedonian – sessile leaf and Turkish – petiolated leaf). • Producers: Turkey, Italy, Greece. • American Type • Large leaf, light texture with high quality tobacco (1.5- 2.0% nicotine and 20-22% sugar). • Varieties: Virginia, Maryland and Burley. • In world tobacco production Virginia (40%) and burley (10%) share is almost 50%. • Producers: USA and India

15. Southern Type • Rich in nicotine (3-4%) and nitrogenous compounds while low in sugar content. • Dark in color thus used for manufacturing low quality cigarette. • Good burning quality. • 2 type of varieties (Argentina and Brazil). • Producers: Brazil, China, Pakistan, India and Argentina. • Island Type • Used for producing top quality cigar (Nicotine up to 3%, many aromatic substance and better burning quality). • Producers: south and central America and Indonesia. • Cigar (Filler: strong, aromatic and burn evenly to form white ash var. Spanish and Dutch; Binder: hold the filler

16. in shape, strong with good burning quality var. Havana; Wrapper: wrapped the cigar, thin and elastic with very fine vein and uniform quality var. Sumatra and Cuban) • Asian Type • The plants of this type of tobacco contains high percentage (3-7%). • It includes chewing tobacco such as – Vairam, Sona. Based on curing methods tobacco are classified as: • Flue Cured Tobacco • Fire Cured Tobacco • Air Cured Tobacco • Sun cured Tobacco

17. Climatic and Edaphic requirements • Tobacco is a tropical crop but also raised in sub-tropical and temperate regions of the world. It is neutral to day length. • The suitable temperature for its cultivation ranges from 22-33°C(day = 24-32°C, night = 18°Cand mean = 26.7°C) and frost free for 90-120 days. • In Nepal, tobacco is grown in the areas with min. temperature of 11.4°C, Max temperature of 25.9°Cand Mean temperature 23.5°C. • For the top quality tobacco, maturation of leaves takes place >18°C. • At low temperature: low metabolic rate, leaf do not grow rapidly, lower physical and chemical condition of leaf.

18. Tobacco seeds require about 21°C temperature for germination. Temperature between 27°C and 32°C are desirable for rapid and uniform germination. • Tobacco is a moisture loving plant, it utilizes considerable amount of moisture to maintain leaf expansion. • Critical period of moisture requirements are seedling stage, rooting stage and rapid stem growth stage. Moisture stress in these stages reduces the budding and flowers and also the leaf yield and quality. • Tobacco needs 100-115 cm well distributed rainfall throughout the growing period. • Areas having a rainfall more than 125 cm are not fit for tobacco production, whereas a rainfall of less than 75 cm results low quality and yield.

19. Excess moisture conditions results in oxygen deficiency which hinders the root growth. Consequently, produces diseased and light weighted leaves. • With low rainfall, plant produces leathery leaves having very high nicotine and calcium content and low potassium and carbohydrates content. The leaves remain smaller and possess very poor burning quality. • Relative humidity is one of the important factors for yield, quality and curing of leaves. The relative humidity of 85-95% is optimum for the crop. Areas with < 50% are not suitable. • Quality of tobacco is greatly influenced by the soil conditions. Tobacco is adopted to moderately acidic soils with a pH ranging from 5.5–6.5.

20. Tobacco is best grown on sand loam surface soil and slightly finer sub soil having ample internal drainage, good aeration and high moisture holding capacity. • However, soil requirements varies according to the classes of the tobacco grown. • Light sandy and sandy loam (low water and nutrient holding) is suitable for large size leaf, light in color, fine in texture and weak in aroma while heavy soil is suitable for smaller leaf, dark colored, heavy body and strong aroma. • Therefore, light colored flue cured and oriental aromatic tobacco are grown on light texture soil with low humus content (up to 2-2.5%) but dark colored tobaccos on rich black soil with over 3-4% humus. • Tobacco will not do well in water logged soils as it is sensitive to water logging and impeded drainage.

22. Varieties Belachapi 1: • Released in 1989 (2046). • Matures in 60-70 days. • Yield potential 0.9 t/ha. • Recommended for terai.

23. Land Preparation • A clean and well pulverized seed bed of good tilth is needed for transplanting tobacco seedlings. • Land should be well prepared first and by deep ploughing with mould board plough followed by 3-4 cross harrowing. • Each harrowing should be followed by planking so that the soil is well pulverized and leveled. • Care should be taken to see the weeds, stubbles etc are well removed from the field. • Red sandy loam soils are preferred for nursery.

24. Seed and Sowing • A seed rate of 200-300 g/ha is optimum for all types of tobacco. Under hot weather conditions, a high seed rate of 400-500 g is recommended. • Sometimes to protect the seedlings from seed-borne diseases, the seed is treated with 2.5% of formaline solution or 0.5% solution of dithane M 45 before sowing in nursery. • Pre-sowing seed soaking in 50 ppm solution of gibberellic acid (G3) for 48 hours increases and hastens the seed germination. • The optimum time for sowing the nursery is the second fortnight of August.

25. Raising Seedlings • Tobacco seeds are very small and so are not sown directly in the field but are raised in a nursery. • Tobacco seedlings are raised in specially prepared raised seed beds (1.25 m width × 10 m length). • Usually, at least 6–8 weeks are required to obtain transplantable seedlings. • Application of FYM or compost at 12.5 kg /2.5m2 as a layer on the top of the beds is found to be highly beneficial in giving higher number of seedlings. • As the size of the seed is very small, it should be mixed with sufficient quantity of sand and evenly distributed over the bed by sowing twice.

26. Watering of nursery beds should be done carefully. The beds should always be kept moist but not wet. In the initial stages, on a sunny day 5–6 watering will be needed. Rose cane is used for watering. • Under favourable conditions, germination starts from 5th day and completed (5–12 days) by 12th day. If the seedlings are over–crowded in some places, they can be thinned out, when three weeks old. • Normally, the seedlings will be ready for transplanting in 6–8 weeks time (42–56 days).

27. Transplanting and Manuring • The field for transplanting tobacco seedlings should be well prepared. • A few hours before transplanting, nursery beds should be well watered to facilitate easy removal of seedlings without root damage. • Fifteen cm height seedlings with 5–7 leaves are good for cigarette tobacco, but bidi tobacco requires smaller seedlings. • Seedlings should be transplanted immediately after pulling in main field with adequate moisture. Transplanting should be done in the late afternoon to avoid heat injury. • Spacing is maintained 75 x 75 cm for chewing tobacco, 75 x 50cm for cigar tobacco and 60 x 45cm for cheroot tobacco.

28. Transplanting is usually done in the month of October–November in case of winter crop, while at the end of March or in the beginning of April for the second or summer crop. Transplanting age of seedlings is 7-9 weeks for tabacum and 5-6 weeks for rustica. • Transplanting of younger seedlings causes a higher percentage of gaps while aged or woody seedlings result in a poor growth of plants. • Recommended dose of fertilizer is 10 t of FYM and 35:23:60 kg NPK/ha. The quality in tobacco, particularly in the smoking types, depends on the balance of the nutrients in the leaf.

29. Heavy application of N increases the yield, but has an adverse effect on the quality. With greater of N supply, the carbohydrate-nitrogen (C:N) ratio gets reduced. • On the other hand, better quality in chewing, bidi and hookah tobaccos is generally associated with higher yields that may be obtained with heavy dose of N together with other nutrients. • In flue cured tobaccos for cigarette and cigar better quality leaves are obtained from partially N starved plants. Therefore, nutrient requirements of different tobaccos are different. • Potash is an important element, particularly for smoking tobacco. Potash also improves the physical qualities of the leaf like elasticity and low prominence of veins.

30. Water Management • Water requirement of tobacco crop depends upon the type of tobacco and the region where it is grown. • In case of cigar and cheroot tobaccos, more frequent light irrigations are needed. • About 15-20 irrigations at 48 hours intervals starting after seedling establishment for chewing and cigar filter tobaccos are required. • Up to 45 days, irrigation is given once in 3–4 days interval and at maturity stage, it is given once in 4–5 days intervals.

31. Weed Management • Intercultural operations should start after 10–15 DAT, when the seedlings are well established. • Orobanche, which is a root parasite and is a menace to the tobacco crop is kept down by hand pulling. • The only way to control this weed is to collect and destroy it before seed formation. Trap cropping of green gram or sesame or sorghum reduces the infestation. • One hand weeding at three weeks after transplanting (or) application of pre-emergence herbicide Fluchoralin at 1 lit/ha or oxyflourfen at 0.5 lit/ha one week prior to planting is recommended.

32. Topping and De-sukering • When flower heads begin to show, the plants are topped by removing off the top of the plant. • Topping means removal of the terminal bud. This practice stimulated the development of the remaining leaves. • It is a very important operation for the quality of tobacco leaf. It gives an uniform quality product leaving 10 leaves on the plant, besides 2 end leaves. • Removal of these suckers is called desuckering. Manual removal of suckers by hand 4–5 times at weekly intervals is done. • The main aim of topping and de-suckering operations is to divert the energy and nutrients of the plant from flower head to leaves, which influence the yield and quality of tobacco.

33. Harvesting • The right stage for harvesting the crop is when the leaves are matured i.e., when the normal 1. green colour changes to yellowish green or slightly yellowish, 2. become thick, spotted and sticky to touch, 3. appearance of brown spots on the leaves, and 4. bulging of interveinal portions on the leaves. If such leaves are bent under thumb, a cracking sound is produced. • There are two methods of harvesting tobacco. • Priming: Harvesting is done by removing few leaves as and when they mature from bottom to top. • Stalk cut method: In this method, the entire plant is cut close to the ground with sickle and left over night in the field for wilting.

34. Curing • Curing is a process by which harvested tobacco leaf is made ready for the market. • Curing is done in order to impart the required colour, texture and aroma to the final product. • It is essentially a drying process whereby most of the moisture of the leaf is removed. • Temperature, relative humidity and air supply are the main factors affecting curing process. • These are responsible for fixation of colour, yellowing of leaves and better quality of cured leaves. These factors vary from method to method of curing. There are four common methods of curing.

35. Flue Curing • The harvested leaves are strung on sticks, which are then stacked in a flue curing barn. The barn is artificially heated. The curing process consists of 3 stages. • Yellowing: • During yellowing, leaf is kept at a low temperature (32–35°C) and high humidity for about (30–40 hrs) till it attains a bright lemon yellow colour. • Fixing colour: • After yellowing, the temperature is raised gradually and humidity of barn is lowered by opening the ventilators with rapid rise in temperature when the-

36. - leaf is still wet results in a bluish-black discolouration called scalding. • It takes about 16–24 hrs. (iii) Drying: • The ventilators are closed and temperature is again gradually raised to 160°F to dry the veins and mid ribs of leaves. • This takes about 28–42 hrs. Then, ventilators are opened to cool down the barn. • The leaves are left in barn overnight for observing moisture to come to normal condition for handling and storage.

37. Air curing • The leaves are divided into groups according to their sizes and are strung on the string secured on a bamboo stick. • These sticks are taken to barn with closed sides and roof. • The leaves are cured under atmospheric temperature and relative humidity of 70–80% is maintained by sprinkling water inside the barn. • The entire process is over in about five to six weeks.

38. Fire curing • The leaves are harvested in such way that a small portion of stem remains attached to the leaves. • The leaves are wilted for a few hours in the field, then tied into bundles and hung in a smoke hut. • They are smoked for about 12 hours by burning dried leaves of trees locally available. • After smoke treatment, the leaf is fermented in bulks for about 3–4 weeks. • The fermented leaves are given treatment with salt water or jaggery solution.

39. Sun curing • Sun curing is done in three ways. (i) Curing whole plants on racks: • After initial wilting in the field, the plants are strung on bamboo poles and cured in sun. Entire process takes about 15–20 days. (ii) Curing leaves with pieces of stems on racks: • Here, racks are not exposed to direct sun, therefore it takes longer period (6–8 weeks). (iii) Curing whole plant on the ground: • Here, leaves are allowed to dry in sun on the ground and are turned over twice a day.

40. This process continues for about a week and then heaps are made which are opened on the next day and reheaped. • This process of heaping, opening the heaps, spreading and reheaping is continued for about 10–15 days. • By the end of this period, leaves becomes completely cured. • For reducing the cost, stringing can be done on wire at 15–22 cm distance. • By the process of turning, the plants on poles could completely be eliminated.