Tobacco

Tobacco

Tobacco (Nicotiana tabacum L.) is a perennial specie grown annually. It is cultivated in an ample range of climates: Tropical, subtropical and temperate. Even though it is sensible to low temperatures, requiring from 90 to 120 frosts free days for its optimum development. At seedling stage, it needs temperatures above 16°C, while in the development period in the field, the ideal range is between 19 to 28°C.

It is a dicotyledonous plant, which re-sprouts when cutting it. Under normal growing conditions, the plant presents a 1 to 2 m height with a leaf production from 15 to 25 per plant. Ninety to 100% of its root weight is concentrated in the first 30 cm depth.

Generally, the crop requires soils with good physical proprieties, adequate balance between air and water, and over all a good internal drainage, since it is very sensible to lack of oxygen at the root zone. The ideal pH is moderate acid to neutral (between 5.2 and 6.5). Soil requirements vary according the tobacco type cultivated. Clear color tobaccos (Virginia and Oriental), prefer lighter texture soils, with a lower cation exchange capacity and less nutrient availability. Darker tobaccos prefer heavier soils, which could have clay texture, with medium organic matter content.

Tobacco is a sensible crop to excess of salts, showing its response to this excess with a lower total plan height and leaf number, with a greater salt content in its tissues (chloride and sodium).

It is a neutral day crop (day length is not a condition for its growing cycle development). Even though, clear days will help to obtain a better expression of the plant potential productivity. Besides, the presence of dry climate during the harvest period helps the drying process.

It is a drought tolerant plant; nevertheless, irrigation is very important for obtaining a good quality tobacco, achieving a larger root development and modifying the physical and chemical proprieties of the cured leaf.

There are different tobacco types, each one characterized by its own morphology, chemical composition and organoleptic proprieties. The tobacco types are: Virginia (covering 60% of the world area), Burley (13% of the area), Fire Cured Tobacco (12%), Oriental (12%), Black (6%) and others, with 9% of the total area.

According to the cigarette parts, tobacco is cultivated for production as follows: Fillers (a leaf mix that forms the cigarette interior), binders (leaves that wrap the filler and keep them together) and cape (external cover of the cigar).

Growth Rates
Tobacco is a rapid growing plant, and the nutrient absorption follows the same pattern, therefore it is fundamental to assure adequate nutrients availability during the vegetative stage, mainly from the first stages post-transplant.

The plant presents great growing rates from early stages. Roots grow rapidly from the 24th to 32nd day after seed germination, as shown in Figure 1. Once seedlings are transplanted in the field, the root system begins to develop, consequently a requirement of a rapid nutrient supply (Figure 1 b).

Figure 1a: Root growing rate before transplant (foot)
Figure 1a: Root growing rate before transplant (foot).

FFigure 1b: Root growing rate after transplant (foot)
Figure 1b: Root growing rate after transplant (foot)

Despite that both growing plant parts (aerial and roots) are in a similar period, the aerial part covers the greatest nutrients´ concentration and dry matter accumulation, as shown in Figure 2.

Figure 2: Dry matter distribution of the tobacco plant. Roots – Stems - Leaves.
Figure 2: Dry matter distribution of the tobacco plant. Roots – Stems - Leaves.
Nutrients most required
The more demanded elements are K, N and Ca, the two first ones are required in large quantities in the first crop stages, as shown in Figure 3. From approximately 13 weeks that the crop remains in the field, K is observed in 85% before the 8th week post-transplant. Then N is absorbed in more than 90% before the 8th week, being very important applying it completely before the 3rd week post-transplant. Then, the plant will have it available between the 4th and 7th week post-transplant, period of very rapid absorption of this element. Besides, it is important that once the plant has reached the leaves maximum development, the soil N content rapidly decreases as assimilable N.

Figure 3a: Accumulation of dry matter, N, P, K, Ca and Mg in tobacco.
Figure 3a: Accumulation of dry matter, N, P, K, Ca and Mg in tobacco.

Figure 3b: Weekly absorption curve of dry matter, N, P, K, Ca and Mg in tobacco.
Figure 3b: Weekly absorption curve of dry matter, N, P, K, Ca and Mg in tobacco.

Ca is demanded by the plant in a more uniform way from the 5th and 10th week, reaching 60% of its absorption in the 8th week post-transplant.

In relation to microelements, their application should be concentrated in the first weeks of the crop growing stage.

The dry matter accumulation is concentrated in 75% of the total between the 6th and the 10th week post-transplant.

The nicotine content of the tobacco crop will depend on the applied nutrition program, the phytotechny procedure used, the leaf maturity grade at the harvest period and climatic conditions during the growing vegetative stage.

It is important to use nitric sources in the tobacco nutrition program and its application in the adequate period, when these are rapidly absorbed by the plants. Nitric sources are transformed in organic compounds and at the harvest time, the nitrate levels in the leaves can be lower which reduces the risk of nitrosamines synthesis, which is potentially carcinogenic. A correct curing process (e.g. indirect heating in the curing process), it is also important to avoid the synthesis of these compounds.
Nutrient absorption
The absorption of elements varies according the tobacco variety, being the black tobacco which accumulates larger nutrients quantities than the Virginia or Oriental types (Table 1).

Nutrients

BURLEY (1)

VIRGINIA (2)

DARK (3)

Nitrogen

202

77

130-150

Phosphorus

22

13

30-40

Potasio

161

88

230-240

Calcio

146

60

200

Magnesio

11

24

25

Azufre

28

20

10

Manganeso

200 gr/ha

0,8

 

Boro

90 gr/ha

0,08

 

Hierro

900 gr/ha

Traces

 

Zinc

200 gr/ha

Traces

 

Cobre

700 gr/ha

0,04

 

Molibdeno

0.4 gr/ha

Traces

 

Table 1: Extracted nutrients by different tobacco types (kg/ha)

It is important considering that plants absorb with greater or minor difficulty depending the distance between the ion solution and the root hairs. For example, N can be absorbed from 20 mm as maximum distance; K, Ca and Mg can be absorbed from 5 to 7 mm maximum and P is absorbed by the plant only if the maximum distance from the root hairs is 1 mm. Then in clay soils, the K of exchange must be in larger quantity for being absorbed by the plant.

Elemento

Rango Normal en %

Nitrógeno

2.0 - 2.75

Fósforo

0.15 - 0.25

Potasio

1.8 - 2.0

Calcio

1.5 - 2.5

Magnesio

0.3 - 0.5

Azufre

0.45 - 0.6

Elemento

Rango Normal en ppm

Boro

20 - 35

Hierro

200 - 800

Zinc

30 - 60

Manganeso

0 - 150

Molibdeno

3 - 6

Cobre

4 - 20

Table 2: Normal foliar levels in Virginia tobacco plants.
Macro and Micro nutrients
Principal macro and micronutrients that play an important role in the tobacco crop are presented as follows.

Nutrient

Common_name

Chemical_formula

Characteristics

Nitrogen

Urea: Urea
Urea Phosphate

CO(NH2)2
CO(NH2)2 H3PO4

It is the more influential element with the quality in the tobacco crop, since it is directly connected with the photosynthesis and production.
Tobacco absorbs Nitrogen mainly in nitric form.
This element is part of the nicotine molecule; by which fertilization directly affect the nicotine content in the leaves.
It is associated with the production of leaves and alkaloids.
It is important to consider that high ammonium content in the soil generates a late Nitrogen absorption, which delay the maturity and affects the leaf quality.
Nitrogen deficiencies: produce high plant with pale and small leaves.
Nitrogen excess: dark leaves, low combustibility and bad flavor. Stems with less mechanical resistance.
Burley and Black Tobacco: 1th Nitrogen application is done at transplant; 2nd 15 days later and 3er, within 30 days after transplant.
Virginia Tobacco: 2 applications: 1th at transplant (60%) and 2nd 3 weeks post-transplant (remaining 40%).

Ammonium: Ammonium Sulphate
Monoammonic Phosphate (MAP)
Diammonium Phosphate (DAP)

(NH4)2SO4
NH4H2PO4
(NH4)2HPO4

Nitrate: Potassium Nitrate
Simple Potassium Nitrate
Solid Calcium Nitrate
Liquid Calcium Nitrate
Magnesium Nitrate
Ammonium Nitrate
Nitric Acid

KNO3
KNO3 NaNO3
(5(Ca(NO3)2) NH4NO3) 10H2O
Ca(NO3)2 in solution
Mg(NO3)2 6H2O
NH4NO3
HNO3

Phosphorus

Monoammonic Phosphate (MAP)
Diammonium Phosphate(DAP)
Monopotasic Phosphate (MKP)
Triple Superphosphate (TSP)
Urea Phosphate
Phosphoric Acid

NH4H2PO4
(NH4)2HPO4
KH2PO4
Principalmente Ca(H2PO4)2
CO(NH2)2.H3PO4
H3PO4

It accelerates maturity of tobacco leaves.
It is associated with the root production and soluble carbohydrates inside the plant, by which is recommended to have a good Phosphorus availability at the transplant period, applying the total amount at this time.
Phosphorus deficiencies: accelerate maturity.

Potassium

Potassium Nitrate
Simple Potassium Nitrate
Potassium
Sulphate
Potassium Magnesium Phosphate
Potassium Bicarbonate
Potassium Chloride

KNO3
KNO3 - NaNO3
K2SO4
K2SO4 - 2MgSO4
KHCO3
KCl

Main component of the tobacco ashes. Its deficiency reduces the roots weight and length more than any other element. It also influences the leaf color, texture, combustibility and hydroscopic characteristics.
It influences more in the quality than yields.
It is considered important for increasing the resistance to fungi diseases and improving drought stress resistance.
It is associated with the leaf production and soluble carbohydrates.
The most rapid source to be available for the plant is Potassium nitrate. Other sources are less soluble and can be toxic to the plant in large quantities.
Virginia Tobacco: 2 applications: 1th at transplant (50-60%) and 2nd application before the 3er week post-transplant. The 2nd application must be exclusively done with Potassium nitrate, source of immediate Potassium availability.
Burley and Black Tobacco: 3 applications, the 2nd 15 days post-transplant and the 3er before 30 days post-transplant.

Calcium

Solid Calcium Nitrate
Liquid Calcium Nitrate
Calcium Chloride

(5Ca(NO3)2) NH4NO3) 10H20
Ca(NO3)2 en solución
CaCl2

It is present in the cellular wall as organic acid soluble salts. It is required for strengthening supporting tissue and the cellular division. It is associated with alkaloids concentration within the plant. Its deficiency is detected by damage of superior leaves, which are deformed taking a hart appearance.
2 applications: 1th at transplant and 2nd at re-sprout, through a rapid assimilate source such as Calcium.

Magnesium

Magnesium Sulphate
Magnesium Nitrate
Potassium and Magnesium Nitrate

MgSO4 7H2O
Mg(NO3)2 6H2O
K2SO4 2MgSO4

Magnesium increment in the leaves improves combustibility and the appearance of ashes, providing a porous, loose and light color ash.
Its deficiency produces thin and paper texture like leaves, with dull, opaque light brown color.
2 applications: 1st at transplant (35%) and the rest before beginning the rapid growing stage (65%).

Sulphur

Magnesium Sulphate
Potassium Sulphate (SOP)
Ammonium Sulphate
Sulfuric Acid

MgSO4 7H2O
K2SO4
(NH4)2SO4
H2SO4

It participates in the essential aminoacid synthesis (cysteine and methionine). It is important to provide the adequate fertilizer dose. Its excess affects the tobacco combustibility and aroma, being very important in Virginia tobacco. Its deficiency produces chlorosis in the leaf tip and affects the normal content of organic compounds.

Nutritional needs of the tobacco plant

Macro Nutrient

FUnction in the Tobacco plant

Boron

It increases yields, imporves combustibility and leaf color and decreases nicotine content.
Its deficiency produces dwarf plants, weak root development, short internodes and possible death of terminal buds.

Zinc

It has a role in the Nitrogen absorption, metabolism for starch formation and promotion of cellular division and elongation. Its deficiency is shown by chlorotic spots on the leaf blade, wich become necrotic and could produce tissue death.

Iron

It is an essential microelement. It participates in the chlorophyll synthesis and oxide reduction reactions. Its deficiency accurs mainly in alkaline soils with 7.5 pH.

Copper

Possibly it acts as combustion catalyzer. It improves root growth and health; stimulates the leaf maturity. It also has effects in the organoleptic quality.

Manganese

It promotes the appeatance of light color ashes, also the formation of clear smoke.
Its excess reduces combustibility and produces the appearance of spots on the leaf blade.

Chloride

Its excess severely effects the tobacco combustibility. Leaf borders become wrinkled and maturity is delay.

Nutritional needs of the tobacco plant.
Black and/or Burley Tobacco
For these tobacco types 3 applications are suggested, as shown in Table 1 a) and b), using either nitric and ammonium sources in case of N, and a rapid absorption source and other of medium speed absorption in case of K.

Nivel de producción Medio

Período de Aplicación

Dosis (kg/há)

Nutrientes (kg/há)

Producto / Fertilizante

N

P2O5

K2O

S

MgO

CaO

B2O3

Qrop™ mix 12-18-18-5-2-5+B

Transplante

500

60

90

90

23

10

23

1

Qrop™ mix 20-00-13-2 Mg-7 Ca

1° Reabone

500

100

0

65

0

10

35

 

Nitrato Simple de Potasio (15-0-14)

2° Reabone

300

45

0

42

 

 

 

 

Fertilización Total

 

1.600

247

108

243

27

22

62

1

Table a). Nutritional program via granular for Back and/or Burley tobacco (medium production level)

Nivel de producción Alto

Período de Aplicación

Dosis (kg/há)

Nutrientes (kg/há)

Producto / Fertilizante

N

P2O5

K2O

S

MgO

CaO

B2O3

Qrop™ mix 12-18-18-5-2-5+B

Transplante

600

72

108

108

27

12

27

1

Qrop™ mix 20-00-13-2 Mg-7 Ca

1° Reabone

500

100

0

65

0

10

35

 

Nitrato Simple de Potasio (15-0-14)

2° Reabone

500

75

0

70

 

 

 

 

Fertilización Total

 

1.600

247

108

243

27

22

62

1

Table b). Nutritional program via granular for Black and/or Burley tobacco (high production level)

The programs, in both tables, are as follows: 1st application dose at transplant, 2nd application 8 days after and 3rd application 21 days after transplant. In the 3rd application, it is recommended K nitrate since it has had good results in acid soils and with high precipitation. In the 2nd nutrition application, it is recommended simple potassium nitrate, mainly in acid soils with high precipitation.
For Virginia tobacco
Despite that the application times are the same than the recommended for Back and Burley Tobacco varieties, it is recommended to apply less unit since the crop is less demanding in term of nutritional requirements, as shown Tables 2 a) and b). In the first application 60% of the element is provided, and in the second 40%, this last application coincides with the beginning of rapid foliar growing from the 4th post-transplant.

Nivel de producción Alto

Período de Aplicación

Dosis (kg/há)

Nutrientes (kg/há)

Producto / Fertilizante

N

P2O5

K2O

S

MgO

CaO

B2O3

Qrop™ mix 9-12-24-7S-2Mg-4Ca+Ba

Transplante

500

45

60

120

35

10

20

1

Nitrato de Potasio Simple (15-0-14)

Reabone

300

45

42

 

 

 

 

 

Fertilización Total

 

900

99

72

186

42

12

24

1

Table a). Nutritional program via granular for Virginia Tobacco (medium production level).

Nivel de producción Alto

Período de Aplicación

Dosis (kg/há)

Nutrientes (kg/há)

Producto / Fertilizante

N

P2O5

K2O

S

MgO

CaO

B2O3

Qrop™ 9-12-24-7S-2Mg-4Ca+B

Transplante

600

54

72

144

42

12

24

1

Nitrato de Potasio SImple (15-0-14)

Reabone

300

45

0

42

 

 

 

 

Fertilización Total

 

900

99

72

186

42

12

24

1

Table b). Nutritional program via granular for Virginia Tobacco (high production level).
Nutritional Plan
Nutritional plan via irrigation and granular

It is recommended applications up to 5 weeks post-transplant. This program consists in periodic applications via irrigation covering the daily crop demands, which make it more efficient.

Fase del desarrollo

N° de dias

Fertilizantes

N° de aplicación

Kg/há a aplicar

Total kg/há

Nutrientes (kg/há)

N

P2O5

K2O

S

MgO

CaO

Transplante desarrollo raíz

0-14

Qrop™ mix 12-18-18-5S-2Mg+4Ca+B

1

350

350

42

63

63

18

7

14

Desarrollo Vegetativo y radicular

14-21

Ultrasol® 15-30-15

8

5

40

6

12

6

0

0

0

Nitrato de Magnesio

8

10

80

9

0

0

0

12

0

Ultrasol® Producción

10

8

80

10

5

32

0

0

0

Fase crecimiento rápido

21-18

Nitrato de Calcio

6

15

90

14

0

0

0

0

23

Sulfato de Magnesio

6

15

90

0

0

0

12

15

0

Ultrasol® Growth

10

8

80

20

8

8

0

0

0

Ultrasol® Producción

10

5

50

7

3

20

0

0

0

Fase Crecimiento Rápido

28-35

Nitrato de Calcio

10

20

200

31

0

0

0

0

52

Sulfato de Magnesio

10

10

100

0

0

0

13

17

0

Ultrasol® 13-06-40

10

12

120

16

7

48

0

0

0

 

Fertirrigación

112

35

114

25

44

75

Total

154

98

177

42

51

89

Table a). Nutritional program via irrigation and granular for Black and Burley Tobacco.

Fase del desarrollo

N° de dias

Fertilizantes

N° de aplicación

Kg/há a aplicar

Total kg/há

Nutrientes (kg/há)

N

P2O5

K2O

S

MgO

CaO

Transplante desarrollo raíz

0-14

Qrop™ mix 12-18-18-5S-2Mg+4Ca+B

1

400

400

48

72

72

20

8

16

Desarrollo Vegetativo y radicular

14-21

Ultrasol® 15-30-15

6

5

30

5

9

5

0

0

0

Nitrato de Magnesio

8

12

96

11

0

0

0

14

0

Ultrasol® Producción

8

8

64

8

4

26

0

0

0

Fase crecimiento rápido

21-18

Nitrato de Calcio

5

10

50

8

0

0

0

0

13

Sulfato de Magnesio

6

10

60

0

0

0

8

10

0

Ultrasol® Producción

8

5

40

5

2

16

0

0

0

Fase Crecimiento Rápido

28-35

Nitrato de Calcio

8

12

96

15

0

0

0

0

25

Sulfato de Magnesio

10

8

80

0

0

0

10

14

0

Ultrasol® 13-06-40

10

8

80

10

5

32

0

0

0

 

Fertirrigación

62

20

78

18

38

38

Total

110

92

150

38

46

54

Table b). Nutritional program via irrigation and granular for Virginia tobacco.
Effect of N source
Effect of N source in performance and the content of Ca and K in the leaves of Flue-Clured snuff.

The following is an investigation at the State University of North Carolina in the USA by McCants, C. Woltz and G. quoted by Hawks, Jr. and W. Collins 1983. Where we investigate the effect of nitrogen source on yield and content of calcium and potassium in the leaves of flue-cured snuff.

The results show that the extent that the ratio of nitrate nitrogen in the culture increases, consistent, so does performance, Effect of N source in performance and the content of Ca and K in the leaves of snuff flue-Clured.

Source: McCants, C. and Woltz G. citado por Hawks, Jr. Y Collins W. 1983. Universidad Carolina del Norte.

Response to the conducted trials

Contenido del Elemento en las hojas

Nitrógeno Nitrico (%)

Ca

K

Rendimiento (kg/ha)

0

60,8

61,2

2.313

33

65,2

62,6

2.387

66

68,9

63,3

2.431

100

72,3

66,6

2.504


Evaluation
Relación nitrato/nitrógeno y producción en cultivos de tabaco.

Description and trail results
A medida que aumenta la proporción de N nítrico en el cultivo, también lo hace el rendimiento.

Efecto de la fuente de Nitrógeno en el Rendimiento y el Contenido de K y Ca de la hoja de Tabaco
Efecto de la fuente de Nitrógeno en el Rendimiento y el Contenido de K y Ca de la hoja de Tabaco

Evaluation
Efecto de la fuente de N en la producción y el contenido de Ca y K en hojas de tabaco curado con calor.

Description and trail results
Asimismo, aumenta el contenido de Ca y K en las hojas.
Effect of nitrogen
Effect of nitrogen applications

The following test was conducted in Brazil by the engineer Sergio Willani and presented at the IX International Seminar on snuff. It worked with increasing doses of nitrogen (5 dose levels, 70, 100, 130, 160 and 190 kg / ha) and three different varieties of flue-cured (K-326, -163 yUlt Ult-106). During the 2000-2001 season. The trial was designed with randomized complete block with three replications. Planting distance was 1.2 meters by 0.5 meters (16,666 plants per hectare).

Pre-plant was fertilized with the mixture in 10 - 16-20, in doses of 600 kg / ha. And it was applied just potassium nitrate (15-0-14). The topping was performed at 18 or 20 leaves per plant. And the results are as follows: The first thing you can see, is that all varieties have a high yield. Reaching more than three tons per hectare in some cases. We also see that yields are directly related to levels of nitrogen applied, ie the higher the level of nitrogen increased yield obtained.

Source: test was conducted in Brazil by the engineer Sergio Willani.
Response to the conducted trials

Nitrogen Dose (kg/ha)

K 326 (Yield)

ULT 163 (Yield)

ULT 106 (Yield)

K 326 (Quality)

ULT 163 (Quality)

ULT 106 (Quality)

70

2214

2367

2479

79,1

77,3

76

100

2551

2647

2839

78,8

79,2

77,6

130

2837

3082

2864

78,5

78,2

77,5

160

3029

3252

3341

77,1

77,6

79,2

190

3315

3584

3671

75,8

77,2

76,6


Evaluation
Relation between N doses, yield and quality.

Description and trail results
All varieties presented high yields, which are directly related with N levels applied.

Response to the conducted trials
Relación entre Distintas dosis de Nitrógeno y sus efectos en Quality de Tabaco Flued-Cured
Relación entre Distintas dosis de Nitrógeno y sus efectos en Quality de Tabaco Flued-Cured

Evaluation
Relation between different N doses and their effect in the fuel-cured tobacco quality.

Description and trail results
Respect to high quality leaves %, the response was not very clear for the U-106 variety. Even though, in the other 2 varieties, there was an inverse relation between the N level applied and the quality obtained. The best quality was obtained around 100 kg/ha of N applied.

Response to the conducted trials
Relation between different N doses and their offect on reductor sugars and Alkaloids in Flue - Cured Tobacco
Relation between different N doses and their offect on reductor sugars and Alkaloids in Flue - Cured Tobacco

Evaluation
Relation between different N doses and their effect on reducing sugars and alkaloids in the fuel-cured tobacco.

Description and trail results
The three varieties show a direct relation between N levels applied and the total alkaloid % in the leaves (as larger N quantity, the larger alkaloid quantity in the leaves). Besides, there is an inverse relation between sugar levels in leaves and the N levels used.
Doses of nitrogen
Effect of different doses of nitrogen

The following is a study performed in Brazil by the same author (engineer Sergio Willani) in snuff Burley. In this case we measured the effect of five different doses of nitrogen (130, 170, 200, 230, 260 and 290 units per hectare) in four different varieties (TN-86, TN-90, 661 and Ult Ult-682). The trial was designed with randomized complete block with three replications. Planting distance was 1.2 meters by 0.45 meters (18,518 plants per hectare). In pre-plant fertilized with 10-18-20 mixture at a dose of 600 kg / ha. And it was applied just potassium nitrate (15-0-14). The topping was performed 20 to 22 leaves per plant.

Source: test was conducted in Brazil by the engineer Sergio Willani.

Response to the conducted trials

N Dosis (kg/ha)

% de hojas de Quality Superior

% de Alcaloides en las hojas

Rendimiento en ton/ha

TN 90

ULT 661

ULT 673

TN 86

TN 90

ULT 661

ULT 673

TN 86

TN 90

ULT 661

ULT 673

TN 86

140

95,1

93,9

95,0

94,4

3,8

3,3

3,7

3,0

2.085

2.318

2.088

2.163

170

94,8

95,2

94,1

95,1

3,4

3,7

3,6

3,5

2.159

2.220

2.189

2.244

200

96,1

95,0

95,5

95,2

3,3

3,4

3,9

3,0

2.516

2.106

2.229

2.358

230

94,0

95,8

95,6

95,6

3,5

3,8

3,2

3,1

1.049

2.148

2.150

2.207

260

96,1

95,3

95,4

96,8

3,9

3,4

3,5

3,2

2.583

2.498

2.586

2.532


Evaluation
Relation between N doses, leaf quality, alkaloid percentage and Burley Tobacco.

Description and trail results
a) and b): 3 of the 4 varieties show an increasing yield tendency as the N doses applied also increased. Similarly, there is an important yield with 200 unit/ha of N for 3 varieties, and all are perform equal when applying 260 unit/ha of N.

Response to the conducted trials
Efecto de la dosis de N en el Rendimiento de Tobaco Burley
Efecto de la dosis de N en el Rendimiento de Tobaco Burley

Evaluation
Effect of different N doses on the Burley Tobacco production.

Description and trail results
a) and b): 3 of the 4 varieties show an increasing yield tendency as the N doses applied also increased. Similarly, there is an important yield with 200 unit/ha of N for 3 varieties, and all are perform equal when applying 260 unit/ha of N.

Response to the conducted trials
Efecto de la dosis de N en las hojas de Alta Quality en Tabaco Burley
Efecto de la dosis de N en las hojas de Alta Quality en Tabaco Burley

Evaluation
Effect of different N doses on the quality of Burley Tobacco leaf.

Description and trail results
As the N dose applied increased, also increased the superior leaf quality %, with the exception of TN-90 variety.

Response to the conducted trials
Efecto de la dosis de N sobre el contenido de Alcaloides totales de la hoja
Efecto de la dosis de N sobre el contenido de Alcaloides totales de la hoja

Evaluation
Effect of different N doses on the total alkaloid content of the tobacco leaf.

Description and trail results
Alkaloid levels in the leaves were maintained relatively stable (between 3 and 4%) independent to the N dose used.
Specialty Plant Nutrition Treatments Resulted in 57% More Gross Margin for Tobacco Grower in Mexico

From November 2010 through May 2011, a field test was carried out on Burley tobacco in Santiago de Ixcuintla (Nayarit State, Mexico). On a tobacco plantation belonging to grower Juan Gonzalez Rangel, associate of the tobacco company Tabacos... Read More.
Seed germination: Seeds are small, weighing 1 gram per 10.000 units. The process between germination to obtaining a seedling ready for transplant takes from 6 to 8 weeks. Temperature, humidity and nutrition are the key factors in this stage.

Nutrition, at this stage, is suggested to be performed at the 2nd week of post-emergence with soluble elements in a N:P2O5:K2O (3:1:3) relation, providing from 100 to 150 ppm of N concentration. Four weeks later repeat the same relation with 100 ppm of N.

Transplant and open field growing: Roots have a very high growing rate from the 5th to the 7th of post-transplant. The root quantity developed will be a key factor for the aerial part development.

 

Figure 1: Average roots organic matter of the tobacco crop
Figure 1: Average roots organic matter of the tobacco crop

After root growing starts, the aerial growth begins from the second month of transplant. This aerial growth reaches the maximum expression from the 5th to 12th weeks of post-transplant, period in which the 85% of the plan aerial dry matter is formed (Figure 2).

Figure 2: Average aerial dry matter of the tobacco plant
Figure 2: Average aerial dry matter of the tobacco plant

At flowering initiation, cutting of flower buds and stem control must be done. This practice allows a better foliar and root development. Two weeks later of this work, harvest should starts.

Normally, the growing cycle of Virginia tobacco takes 90 days and Burley tobacco 120 days. Afterward harvest is conducted, which can last from 5 to 7 weeks, depending the crop and climatic conditions.


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