Effect of Nitrogen Rate and Cultivar on Burley Tobacco · 2013-06-06 · tobacco growers with recommendations for application of nitrogen fertilizer to newer cultivars. The effect

Effect of Nitrogen Rate and Cultivar on Burley Tobacco (Nicotiana tabacum L.) Yield and Leaf Quality

A Thesis Presented for the Master of Science

Degree The University of Tennessee at Martin

David Kaleb Rathbone December 2008

ii

Acknowledgements

I would like to thank Mr. Bill Teague, Superintendent of the Mountain

Research Station, for allowing me the freedom to work on this project. I would also

like to thank Dr. Greg Hoyt, for without his generous support of time and resources,

this thesis would not have been possible.

I would like to acknowledge Dr. Barb Darroch and Dr. Wes Totten for editing

the document and Dr. Tim Burcham for guidance throughout the MSANR program.

My sincerest appreciation is extended to my wife Monica who always provides

never-ending support and encouragement for everything I do.

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Abstract

Proper management of nitrogen application is imperative for producing quality

burley tobacco. Current nitrogen recommendations for North Carolina are based on

older burley tobacco cultivars. Improved cultivars with high yield and disease

resistance have been developed. The objective of this study was to provide burley

tobacco growers with recommendations for application of nitrogen fertilizer to newer

cultivars. The effect of nitrogen rate and cultivar on tobacco growth, yield, and leaf

quality was investigated.

Five burley cultivars were used in this study: TN 90, KT 204, NC 2000, NC 7,

and Clay’s 403. All cultivar treatments received 112 kg N ha-1 as a pre-plant broadcast

application. Additional nitrogen fertilizer was side-dressed 30 days after planting.

The four nitrogen treatments (broadcast plus side-dressed) were 112, 168, 224, and

280 kg N ha-1. A factorial randomized complete block design with four blocks was

used at each location.

Trials were conducted in 2005, 2006 and 2007 at two locations, the Upper

Mountain Research Station, Laurel Spring, NC, and the Mountain Research Station

(MRS), Waynesville, NC. At the MRS, trials were established on a bottomland soil

and an upland terrace location. Height and flowering data were collected in late

summer. Yield data were collected after barn curing as the tobacco was graded. A

tobacco grader from North Carolina State University determined leaf grades and a

quality index was calculated for each treatment.

iv

Nitrogen rate affected tobacco height, time of flowering, yield, and leaf quality

at each location. Plant growth and yield data for the heavier clay soil (upland location

at MRS) showed that the 224 kg N ha-1 nitrogen rate (currently recommended to

growers) provided maximum yield of burley tobacco. At the two sandy soil locations,

the highest yields were produced by the 224 and 280 kg N ha-1 rates. The 280 kg N

ha-1 rate produced the highest yield in only one out of six location/years on the sandy

soils. Results indicated the newer burley tobacco cultivars (TN 90, KT 204, NC 2000,

and NC 7) produced maximum yield at the recommended 224 kg ha-1 rate of nitrogen.

v

Table of Contents Page Chapter I ..................................................................................................................1 Introduction .............................................................................................................1 Research Objectives ............................................................................................2 Chapter II.................................................................................................................3 Literature Review ....................................................................................................3

Overview of Tobacco Production........................................................................3 Soil Nitrogen and Nitrogen Fertilizer..................................................................5 Cultivars Used in the Study.................................................................................7

Chapter III .............................................................................................................11 Research Methods .................................................................................................11 Chapter IV .............................................................................................................15 Results ...................................................................................................................15

Tobacco Height .................................................................................................15 Flowering...........................................................................................................19 Yield ..................................................................................................................23 Quality ...............................................................................................................31

Chapter V...............................................................................................................35 Conclusions ...........................................................................................................35 Literature Cited......................................................................................................37 Appendix A ...........................................................................................................41 Plot Plans ...............................................................................................................41 Appendix B............................................................................................................44 ANOVA Tables .....................................................................................................44 Appendix C............................................................................................................54 Weather Data .........................................................................................................54 Vita ........................................................................................................................85

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List of Tables Page

Table 1. Burley tobacco varieties used in this study and relative levels of disease resistance (from Ivors and Shoemaker, 2007).................................................................9

Table 2. Yield and grade index of burley tobacco cultivars..........................................10

Table 3. Quality index values for government grades of burley tobacco (Bowman, et. al., 1989)........................................................................................................................14

Table 4. Effect of cultivar and nitrogen rate on mean burley tobacco height (cm) at the upland and river bottom locations of the Mountain Research Station and at the Upper Mountain Research Station in 2005 ..............................................................................16



Table 7. Effect of cultivar and nitrogen rate on mean burley tobacco flowering (%) at the upland and river bottom locations of the Mountain Research Station and at the Upper Mountain Research Station in 2005 ...................................................................20



Table 10. Effect of year and location on mean burley tobacco yield and quality analyses by location and year. .......................................................................................24

Table 11. Rainfall totals by month, location and yearz..................................................25

Table 12. Results of combined statistical analyses for all locations and years in the burley tobacco experiment. ...........................................................................................26

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Table 13. Effect of cultivar and nitrogen rate on mean burley tobacco yield (kg ha-1) at each site at the upland and river bottom locations of the Mountain Research Station and at the Upper Mountain Research Station in 2005...................................................27



Table 16. Effect of cultivar and nitrogen rate on mean burley tobacco quality index at each site at the upland and river bottom locations of the Mountain Research Station and at the Upper Mountain Research Station in 2005...................................................32



Table B.1. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the River Bottom Location, Mountain Research Station, 2005. .........................................45

Table B.2. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the Upland Location, Mountain Research Station, 2005.....................................................46

Table B.3. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the Upper Mountain Research Station, 2005.......................................................................47

Table B.4. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the Bottom Location, Mountain Research Station, 2006 ....................................................48


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Table B.7. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the River Bottom Location, Mountain Research Station, 2007 ..........................................51



Table C.1. Weather Data Laurel Springs, NC May 2005..............................................55

Table C.2. Weather Data Laurel Springs, NC June 2005..............................................56

Table C.3. Weather Data Laurel Springs, NC July 2005 ..............................................57

Table C.4. Weather Data Laurel Springs, NC August 2005 .........................................58

Table C.5. Weather Data Laurel Springs, NC September 2005....................................59

Table C.6. Weather Data Laurel Springs, NC May 2006..............................................60

Table C.7. Weather Data Laurel Springs, NC June 2006..............................................61

Table C.8. Weather Data Laurel Springs, NC July 2006 ..............................................62

Table C.9. Weather Data Laurel Springs, NC August 2006 .........................................63

Table C.10. Weather Data Laurel Springs, NC September 2006..................................64

Table C.11. Weather Data Laurel Springs, NC May 2007............................................65

Table C.12. Weather Data Laurel Springs, NC June 2007............................................66

Table C.13. Weather Data Laurel Springs, NC July 2007 ............................................67

Table C.14. Weather Data Laurel Springs, NC August 2007 .......................................68

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Table C.15. Weather Data Laurel Springs, NC September 2007..................................69

Table C.16. Weather Data Waynesville, NC May 2005 ...............................................70

Table C.17. Weather Data Waynesville, NC June 2005 ...............................................71

Table C.18. Weather Data Waynesville, NC July 2005 ................................................72

Table C.19. Weather Data Waynesville, NC August 2005 ...........................................73

Table C.20. Weather Data Waynesville, NC September 2005......................................74











x

1

Chapter I

Introduction

Tobacco, Nicotiana spp., is a member of the nightshade (Solanaceae) family.

Currently there are 70 naturally occurring species of tobacco (Lewis and Nicholson,

2007). Burley tobacco (N. tabacum L.) is the most common type of tobacco grown in

western North Carolina.

Due to increased prices of fuel, labor and other inputs, the cost of producing

quality burley tobacco has risen to historically high levels. Currently, producers are

faced with a smaller profit margin than in the past, so it is imperative that farmers

manage production costs by being as efficient in their production practices as possible.

While many production costs such as labor can vary from farm to farm, agronomic

inputs remain relatively fixed. However, these costs depend on recommended rates of

crop protectants and fertilizers. One of the highest costs of production is nitrogen

fertilizer. This also is one of the most important inputs for growers to manage because

nitrogen fertilizer affects burley tobacco yield and quality (Davis and Nielsen, 1999).

Researchers have recommended that 180 kg N ha-1 to 224 kg N ha-1 be applied

to burley tobacco in North Carolina (Shelton, 1987; Hoyt, 2008). These nitrogen

fertilizer recommendations serve as a useful guide for burley tobacco production

(Evanylo et al., 1988). While these recommended rates have served North Carolina

producers well for many years, these recommendations were based on older varieties

that were grown several years ago. Many improved burley tobacco cultivars with

increased disease resistance and potentially greater yields are now available (Miller,

2

2005). Agronomic recommendations for these new cultivars are currently being

developed in the burley tobacco growing region.

Timing of nitrogen fertilizer application is an important consideration

(Waynick et al., 2006). Burley tobacco cultivars vary in time to maturity, with early

maturing cultivars needing more nitrogen earlier in the growing season than those that

are late maturing. If nitrogen fertilizer is applied too early in the plant’s life cycle,

excessive rainfall can cause nitrate leaching before the plant is able to utilize this

available nitrogen. If this occurs, the producer may not achieve full benefit from the

nitrogen application. To minimize nitrogen loss, application of nitrogen fertilizer

should be split with an initial pre-plant application followed by an application four

weeks after planting (Collins and Hawks, 1993). Producers must be careful with

timing and rate of nitrogen fertilizer applications, as excessive nitrogen can have

adverse effects on cured leaf quality. This creates an inferior product and can result in

lower market premiums for the leaf (Collins and Hawks, 1993).

Research Objectives This experiment was designed to meet the following research objectives:

1. Determine the effect of nitrogen rate on growth, yield, and leaf quality of five

burley tobacco cultivars;

2. Determine nitrogen utilization in early maturing versus late maturing varieties;

and

3. Provide burley tobacco growers with detailed recommendations for application of

nitrogen fertilizer.

3

Chapter II

Literature Review

Overview of Tobacco Production

Tobacco (Nicotiana tabacum L.) production and marketing have undergone

many changes since tobacco was first produced commercially (Greene, 1996).

Today’s tobacco producers face the challenge of producing the highest quality tobacco

for the same premium that was paid for burley tobacco over 20 years ago. While the

price per pound of tobacco is the same as it was 20 years ago, the cost of production

has increased considerably (USDA, 1990).

Burley tobacco is an air cured type of tobacco and has been historically

produced primarily in Western North Carolina, East Tennessee, and Kentucky. The soils

and climate of these areas are well suited for production and curing of burley tobacco.

Government regulation also restricted expansion of production into other areas (Greene,

1996). In recent years, after the tobacco quota buyout of 2005, geographic restrictions

on burley tobacco production have been lifted. While there has been some expansion of

burley tobacco production into non-traditional areas, the main burley tobacco growing

areas are still Western North Carolina, East Tennessee, and Kentucky.

For optimum yields in Western North Carolina, tobacco should be transplanted

between May 20 and May 30 and harvested in mid September. (Shaw et al., 1965).

Burley tobacco is generally planted on 122 cm row spacing and 46 cm plant spacing.

This spacing gives the producer a population of 17,819 plants per hectare. Pesticides

4

labeled for weed, plant disease, and insect controls are applied at appropriate times,

with weeds also controlled by cultivation and or/by hand.

Nitrogen is one of the most important plant nutrients in tobacco production

(Collins and Hawks, 1993). Incorrect nitrogen application rates will reduce net

income. Over-application of nitrogen can lower leaf quality, cost growers additional

expense, and potentially lead to nitrogen loss by soil erosion or leaching below the

root zone. Under application of nitrogen can result in lower burley tobacco yields,

reducing net income to the grower (Flower, 1999).

One of the largest production costs for burley tobacco is nitrogen fertilizer. On

average, burley tobacco producers spend over $700.00 per ha on nitrogen fertilizer. Other

major inputs include labor, crop protectants, facilities and equipment (Brown, 2008).

Soil type plays an important role in nutrient management in tobacco

production. Clay soils tend to retain nitrogen better than sandy soils, which are prone

to nutrient leaching if rainfall is excessive. Nitrogen leaches more readily from sandy

soils because they have larger pores between soil particles and less surface area than

soils with high clay content. Sandy soils also have a lower cation exchange capacity

than clay soils. Cation exchange capacity is the quantity of negative charges in soil.

Soils with high cation exchange capacity can bind positive charged plant nutrients

(NH4+, K+, Ca++, Mg++), reducing leaching of these nutrients (Camberato, 2001). More

water can move through large pore spaces than smaller pore spaces found in clay soils.

As water moves downward (due to gravity) nitrates in solution also move through the

soil which reduces nitrogen availability to plants (Killpack and Buchholz, 1993).

5

Soil Nitrogen and Nitrogen Fertilizer Nitrogen concentration in soil fluctuates from near zero to more than 2.5%,

and the amount of plant available nitrogen depends, to a large extent, on the amount of

organic matter in the soil (Carrow et al., 2001). The amount of nitrogen taken up and

utilized by a plant also depends on the amount of moisture in the soil. Irrigation can be

used to increase soil moisture levels and increase yields (Sifola and Postiglione, 2003).

Irrigation can help plants take up nitrogen, but could potentially increase leaching of

nitrate nitrogen.

Movement of nitrogen throughout soil, plants and the atmosphere can best be

explained by the nitrogen cycle (Figure 1). One of the most abundant sources of

nitrogen is atmospheric nitrogen. Approximately 78% of air is nitrogen (Microsoft

Encarta Online Dictionary, 2007). Conversion of this nitrogen to plant available

nitrogen in natural systems is mainly through biological nitrogen fixation (Carrow et

al., 2001). Biological nitrogen fixation is primarily carried out in legume crops which

form a symbiotic relationship with Rhizobium bacteria. This biologically fixed

nitrogen can be available to succeeding crops after the legume crops decompose.

Another way that atmospheric nitrogen can be converted to plant available

nitrogen is through lightning (Allison, 1957). Since lightning cannot be easily

harnessed to provide a consistent source of nitrogen to plants, a third method of

nitrogen conversion has been developed. Industrial nitrogen fixation through the

Haber-Bosch process is used to create synthetic nitrogen fertilizer (Carrow et al.,

2001).

6

Figure 1. The nitrogen cycle in soil (Brown and Johnson, 1991)

7

There are different sources of nitrogen in the soil and each pool has different

plant availability. Nitrogen is taken into plants in only two forms. These forms are

NO3-(nitrate) and NH4

+ (ammonia). Microbes in the soil convert nitrogen found in soil

organic matter or fresh plant material into one of these two forms (Dorn, 2001).

To take advantage of biologically fixed nitrogen, tobacco can be planted after

winter legume cover crops, or perennial crops such as alfalfa, are plowed into the soil

(Hoyt and Hargrove, 1986). Animal manures can also be utilized as plant nutrients on

the farm, but availability is dependent on other farm strategies for income (animal

production) or distance to an available source (Vaughn et al., 2007/ 2008). However,

the majority of nitrogen used in tobacco production is made available through the

application of synthetic nitrogen fertilizers.

Various synthetic fertilizers are used in tobacco production. Ammonium nitrate

(NH4 NO3), which contains 34% nitrogen, has been widely used in the past

(Pendergrass, 1952). Another form of nitrogen fertilizer that is becoming increasingly

popular with tobacco growers is liquid urea ((NH2)2CO) ammonium nitrate. This

product is available as either 30% nitrogen or 32% nitrogen (Terra Industries Inc.,

2006). While liquid fertilizer is often less expensive than granular fertilizers, many

farmers do not use it for tobacco production. This is likely due to the cost of

equipment modifications or other purchases required to apply liquid fertilizers.

Cultivars Used in the Study

Cultivars can differ in their response to nutrients available in the soil (Hiatt,

1963). A producer should keep this in mind when selecting a cultivar. Some cultivars

8

contain genes that confer disease resistance. However, in some cases genes that create

disease resistance may not have the potential for excellent yields (Lewis et al., 2007).

This can reduce the return on a producer’s investment, even with higher levels of

disease resistance.

The five cultivars used in this study varied in relative levels of disease

resistance (Table 1) and yield potential and quality (Table 2). For example, Clay’s 403

has excellent yield potential but is highly susceptible to blue mold (Peronospora

tabacina) (Table 1). NC 2000, a recent cultivar with blue mold resistance, has no

tolerance to black shank. TN 90, KT 204, and NC 7 are fairly new releases that have

good yield potential due to their resistance to some tobacco diseases but all are

susceptible to blue mold. According to North Carolina Official Variety Tests, Clay’s

403 traditionally has high yields, but only in locations where root diseases were not

present and in years when blue mold had not been established (Table 2). Clay’s 403

has a very low level of resistance to all diseases listed (Table 1). This is apparent by

looking at the tobacco leaf grade index for Clay’s 403, which was the lowest of the

five cultivars shown (Table 2). Clay’s 403, TN 90, and KT 204 are earlier maturing

while NC 7 and NC 2000 mature later. In certain locations, such as Laurel Springs,

NC, where growing seasons are short, late maturing varieties may not have enough

time to reach full yield potential.

9

Table 1. Burley tobacco varieties used in this study and relative levels of disease resistance (from Ivors and Shoemaker, 2007)

Variety

Disease Clay’s 403 KT 204 NC 2000 NC 7 TN 90 Black Root Rot S* H L H H Mosaic - H H H H Fusarium Wilt - S VS - VS Wildfire - H H - H Black Shank S H S H M Brown Spot - - S H - Vein Mottling - H S - H Etch - M S - M-H Blue Mold VS S M - T

*S = susceptible; VS = very susceptible; H = high level of resistance; M = moderate level of resistance; L = low level of resistance; T= tolerant - = no data

10

Table 2. Yield and grade index of burley tobacco cultivars

Variety Yield (kg ha-1) Yield (lbs acre-1) Grade Indexz

Clay’s 403** 3868 3,450 68 TN 90* 3324 2,965 77 NC 2000* 3056 2,726 78 NC 7* 3716 3,315 80 KT 204* 3811 3,400 76

* North Carolina Official Variety Test, Mountain Research Station (Fisher et al.,

2008) ** North Carolina Official Variety Test, Mountain Research Station (Smith and

Whitley, 2005) z Grade index is calculated based on the government quality grade assigned to the

tobacco leaf

11

Chapter III

Research Methods This study was conducted during the growing seasons of 2005, 2006, and 2007

at the Upper Mountain Research Station (UMRS) located near Laurel Springs, NC and

the Mountain Research Station (MRS) in Waynesville, NC. At the MRS two sites

were established for the experiment, an upland heavy clay location and a river bottom

site with a sandy loam soil. The soil series at the UMRS was a Toxaway loam (a fine-

loamy, mixed, nonacid, mesic Cumulic Humaquept). Trials at the river bottom

location of the MRS were established on a French loam (a fine-loamy, over sandy or

sandy skeletal, mixed, mesic Fluaquentic Dystrochrepts). A Dyke clay soil (clayey,

mixed, mesic Typic Rhodudults) was found at the upland site.

Tobacco seedlings for the trials were grown in the greenhouse at the MRS.

Seedlings were started the first week of April each year, and transplanted to the field

during the first week of June.

All production practices (except for nitrogen application) were based on

recommendations set forth in the North Carolina Cooperative Extension Service’s

Burley Tobacco Production Guide (North Carolina Cooperative Extension Service,

2008).

Five burley tobacco cultivars were used throughout the study: TN 90, KT 204,

NC 2000, NC 7, and Clay’s 403. These cultivars were selected because of present or

past use by growers throughout the burley growing region of the United States. The

cultivars differ in maturity characteristics and level of resistance or tolerance to

12

common burley diseases (Tables 1 and 2). In addition to these five cultivars, an

additional experimental cultivar was grown each year. This variety was not included in

final analysis and discussion because the cultivar was not released for production.

Research plots at each site were set up as a factorial randomized complete

block design with four blocks. Treatment factors were cultivar and nitrogen rate.

Ammonium nitrate (34 % nitrogen) was applied pre-plant and as a side-dress

application. Phosphorus and potassium were applied pre-plant based on soil test

recommendations. All treatments received 112 kg N ha-1 as a pre-plant broadcast

application. Additional nitrogen fertilizer was side-dressed at varying rates 30 days

after planting. The four nitrogen treatments were 112, 168, 224, and 280 kg N ha-1

(pre-plant plus side-dress). This wide range in rates was chosen because the study also

included disease ratings based on nitrogen rates for a separate publication. Pesticides

to control weeds and insects were applied as needed. Plants were topped, harvested,

and air cured by standard burley practices (North Carolina Cooperative Extension

Service, 2008).

Flower counts were taken beginning at the elongated bud stage through

topping. Height was measured 8 to 10 weeks after transplanting and was determined

by taking the average of 12 plants per plot.

Yield data were collected for all locations throughout the three year period of

the experiment. The plots were harvested and air cured with five stalks per stick. The

tobacco leaves were stripped from the stalk in a controlled environment. The

temperature in the facility was maintained at 20° C and the relative humidity was kept

13

between 75% and 80%. With this controlled environment, moisture content did not

affect tobacco leaf weight.

Leaf quality was measured at all locations across all three years, with one

exception. Due to an error in the experiment, quality data from the 2005 MRS River

Bottom location was not collected. The leaf quality rating was developed at North

Carolina State University based on the traditional government grading system

(Bowman et al., 1989). Glen Tart, a tobacco grader from North Carolina State

University, evaluated each plot and assigned a grade to each of the four stalk

positions. This grade was then translated into a corresponding grade index based upon

the grade index table (Table 3). The grade index is based on a formula with 100

representing the highest quality leaf and 1 representing the lowest quality (Bowman et

al., 1989).

All data were analyzed using the GLM procedure of SAS (SAS Institute,

2006). Main effects and interactions were tested using ANOVA. The effect of N

fertility level was determined using single degree of freedom polynomial (linear,

quadratic and cubic) orthogonal contrasts. Contrasts were also used to compare late

versus early maturing cultivars for all variables. In addition, Duncan’s multiple range

test (α = 0.05) was used to compare cultivar means.

14

Table 3. Quality index values for government grades of burley tobacco (Bowman, et. al., 1989)

Flyings Leaf Tips

X1L 86 B1F 100 T3F 70 X2L 76 B2F 90 T4F 60 X3L 66 B3F 80 T5F 50 X4L 56 B4F 70 T3FR 70 X5L 46 B5F 60 T4FR 60 X1F 90 B2FL 75 T5FR 50 X2F 80 B3FL 65 T3R 70 X3F 70 B4FL 55 T4R 60 X4F 60 B1FR 100 T5R 50 X5F 50 B2FR 90 T4D 36 X4M 44 B3FR 80 T5D 26 X5M 34 B4FR 70 T4K 32 X4G 24 B5FR 60 T5K 22 X5G 14 B1R 100 T4VF 36

B2R 90 T5VF 26 Cutters B3R 80 T4VR 36

C1L 95 B4R 70 T5VR 26 C2L 85 B5R 60 T4GF 24 C3L 75 B4D 40 T5GF 14 C4L 65 B5D 30 T4GR 24 C5L 55 B3K 45 T5GR 14 C1F 100 B4K 35 C2F 90 B5K 25 Mixed

C3F 80 B2M 70 M3F 50 C4F 70 B3M 60 M4F 40 C5F 60 B4M 50 M5F 30 C3K 45 B5M 40 M3FR 50 C4K 35 B3VF 50 M4R 40 C5K 25 B4VF 40 M5FR 30 C3M 60 B5VF 30 M4K 26 C4M 50 B3VR 50 M5K 16 C5M 40 B4VR 40 C3V 50 B5VR 30 Nondescript

C4V 40 B3GF 35 N1L 30 C5V 30 B4GF 25 N2L 10 C4G 25 B5GF 15 N1F 30 C5G 15 B3GR 35 N1R 30

B4GR 25 N2R 10 B5GR 15 N1G 10 N2G 5

15

Chapter IV

Results

Tobacco Height Cultivars used in this experiment were representative of the range in maturity

types of burley tobacco cultivars. This was reflected in height data collected. While

greater heights do not necessarily translate into higher yields, effects of nitrogen rate

on the different cultivars were evident.

Height measurements were taken throughout the growing season at all three

locations and for each of the three years of production. Tobacco height data are

summarized in Tables 4 through 6. Height of the earlier maturing varieties Clay’s 403

and TN 90 was significantly greater than the later maturing varieties NC 7, KT 204,

and NC 2000, as shown by the significant contrast for all locations and years (P <

0.005) except for the upland location at the MRS in 2006 (Table 5).

Significant (P < 0.05) differences for height were observed among cultivars at

all locations and years except the UMRS location in 2007 (Appendix B). The only

significant interaction between N rate and cultivar for plant height (P = 0.024) was

observed at the upland location, MRS in 2006 (Table B.5). Nitrogen rate had a

significant effect on height (P < 0.02) at the UMRS in 2005 and 2006 (Tables B.3 and

B.6). In addition, polynomial contrasts showed that there was a linear response of

height to N rate (P < 0.005) at the UMRS in 2005 and 2006 (Tables 4 and 5). Most of

the fertilizer applied during side dressing was available for the most vigorous period of

plant growth, leading to the observed linear response to nitrogen rate.

16

Table 4. Effect of cultivar and nitrogen rate on mean burley tobacco height (cm) at the upland and river bottom locations of the Mountain Research Station and at the Upper Mountain Research Station in 2005

zLetters within a column and within a treatment factor followed by the same letter are not significantly different by Duncan’s multiple range test (P ≤ 0.05). yValues for contrasts represent P values from the F test (Pr > F). x Contrasts for Early vs. late maturing tobacco: Early includes Clay 403, KT 204 and

TN 90, Late Maturing NC 7 and NC 2000.

Tobacco Height (cm) Mountain Research Station Upland

Location River Bottom

Upper Mountain

Station Cultivar Clay 403 149az 145az 160az NC 7 132b 126b 138c KT 204 140ab 136ab 151b TN 90 137ab 142a 148b NC 2000 114c 112c 122d Early vs. late maturingx 0.0011y 0.0001y <0.0001y Nitrogen Rate 112 kg N ha-1 130az 128az 139bz 168 kg N ha-1 135a 132a 139b 224 kg N ha-1 133a 133a 149a 280 kg N ha-1 141a 137a 150a Linear Contrast 0.0802y 0.1348y <0.0001y Quadratic Contrast 0.6194 0.9747 0.6732 Cubic Contrast 0.3724 0.6690 0.0436

17




Tobacco Height (cm) Mountain Research Station

Upland Location River Bottom

Upper Mountain

Station Cultivar Clay 403 111az 129az 125az NC 7 100ab 119b 116b KT 204 107ab 124ab 118b TN 90 105ab 132a 115b NC 2000 91b 104c 99c Early vs. late maturingx 0.0987y <0.0001y <0.0001y Nitrogen Rate 112 kg N ha-1 101az 126az 109bz 168 kg N ha-1 105a 121a 117a 224 kg N ha-1 100a 121a 115a 280 kg N ha-1 106a 119a 118a Linear Contrast 0.6383y 0.1348y 0.0046y Quadratic Contrast 0.8536 0.9747 0.1679 Cubic Contrast 0.3896 0.6690 0.1051

18




Tobacco Height (cm) Mountain Research Station


Upper Mountain

Station Cultivar Clay 403 71az 101abz 70az NC 7 64ba 95b 58ab KT 204 54bc 97b 68a TN 90 62abc 105a 69a NC 2000 53c 84c 52b Early vs. late maturingx 0.0033y <0.0001y 0.0037y Nitrogen Rate 112 kg N ha-1 61az 96az 63az 168 kg N ha-1 60a 95a 65a 224 kg N ha-1 59a 98a 66a 280 kg N ha-1 64a 97a 59a Linear Contrast 0.5990y 0.2975y 0.4717y Quadratic Contrast 0.3495 0.9125 0.2131 Cubic Contrast 0.6763 0.2267 0.6310

19

Flowering Tobacco flowering is a physiological characteristic that differs among tobacco

cultivars. In this study, flowering data were collected multiple times between the

elongated bud stage to full flower and topping at all locations (Tables 7 through 9).

A tobacco plant will grow and mature according to its general genetic makeup,

with some cultivars flowering and maturing earlier than others. Low nitrogen

availability late in the growing season can trigger a physiological response that results in

earlier tobacco flowering. This could have occurred in the locations where there was a

significant interaction between cultivar and N rate (Appendix B). Significant cultivar by

N rate interactions were observed at the River Bottom Location at the MRS in 2006 (P =

0.0189) and at the upland location at the MRS in 2007 (P < 0.05; Tables B.4 and B.8).

As nitrogen becomes depleted to a maturing tobacco plant, the plant can enter

the reproductive phase of its life cycle. This was observed with flowering data at five

of the nine location/years (Tables 7 through 9). There was less influence on percent

flowering early when tobacco was first flowering, but more influence of N rate later in

the growing season. This is evident by the significant linear contrasts for N rate in

2005 and 2006 (P < 0.04).

When tobacco blooms earlier in the plant’s life cycle, it reduces the period of

time the plant has to produce leaf mass and subsequently reduces crop yield. Time of

tobacco flowering also affects when the plant should be topped. Topping is the process

of cutting the blooms off the plants. By removing the flowers, plants are forced to stop

growing taller and allocate more carbohydrates to roots and leaves. Traditionally,

20

Table 7. Effect of cultivar and nitrogen rate on mean burley tobacco flowering (%) at the upland and river bottom locations of the Mountain Research Station and at the Upper Mountain Research Station in 2005



Tobacco flowering (%) Mountain Research Station


Upper Mountain

Station Cultivar Clay 403 90az 85az 87az NC 7 48b 33b 8b KT 204 79a 86a 80a TN 90 82a 94a 77a NC 2000 44b 17c 7b Early vs. late maturingx <0.0001y <0.0001y <0.0001y Nitrogen Rate 112 kg N ha-1 58bz 59az 48bz 168 kg N ha-1 73a 65a 46b 224 kg N ha-1 71a 64a 59a 280 kg N ha-1 72a 65a 55ab Linear Contrast 0.0136y 0.2382y 0.0285y Quadratic Contrast 0.0467 0.4314 0.8142 Cubic Contrast 0.1845 0.6537 0.0434

21






Upper Mountain

Station Cultivar Clay 403 53az 51az 80az NC 7 14b 2d 5d KT 204 43a 17c 50c TN 90 61a 64a 67b NC 2000 13b 2d 4d Early vs. late maturingx <0.0001y <0.0001y <0.0001y Nitrogen Rate 112 kg N ha-1 40az 32az 29bz 168 kg N ha-1 39a 27ab 47a 224 kg N ha-1 39a 30ab 39ab 280 kg N ha-1 40a 20b 50a Linear Contrast 0.1982y 0.0372y 0.0036y Quadratic Contrast 0.4517 0.5732 0.4133 Cubic Contrast 0.7094 0.2059 0.0199

22






Upper Mountain

Station Cultivar Clay 403 49abz 51az 83az NC 7 21b 1c 69ab KT 204 34ab 17b 70ab TN 90 54a 60a 87a NC 2000 36ab 2c 58b Early vs. late maturingx 0.0177y <0.0001y 0.0037y Nitrogen Rate 112 kg N ha-1 41az 25abz 76az 168 kg N ha-1 46a 18b 78a 224 kg N ha-1 37a 30a 69a 280 kg N ha-1 32a 30a 71a Linear Contrast 0.3459y 0.0995y 0.4717y Quadratic Contrast 0.5764 0.3499 0.2131 Cubic Contrast 0.6559 0.0407 0.6310

23

plants are topped when 50% of the plants in the field are in bloom, allowing greater

efficiency for the grower to top the entire field (assuming same variety throughout the

field), rather than individually topping each plant when flowering begins. In these

experiments, NC 2000 and NC 7 flowered later than the other cultivars tested (Tables

7 through 9). These differences can be clearly seen in the significant early vs. late

maturing contrasts (P < 0.02) as well as in the results from Duncan’s multiple range

tests. Both of these cultivars are late maturing, which can create a problem in areas

with a shorter growing season (similar to the weather conditions at the UMRS). If late

maturing varieties are planted later than recommended dates, they may not have

enough time to reach full yield potential during the growing season.

Yield Mean burley tobacco yield and quality are presented in Table 10. The best

burley tobacco yield (3405 kg N ha-1) was obtained in the 2007 growing season.

Because 2007 was an exceptionally dry year (Table 11 and Appendix C), irrigation

was applied as needed and disease pressure was minimal.

Table 12 shows results for combined analysis from all locations and years.

There were significant year by location interactions (P < 0.0001); therefore the data

were analyzed separately for each location within each year.

Burley tobacco yield results for 2005, 2006, and 2007 at all locations are

shown in Tables 13 through 15. The effect of cultivar on yield was significant at all

locations within all years (P < 0.02; Appendix B) except for the upland location at

MRS in 2005 and 2007 (Tables B.5 and B.7). No significant cultivar by N rate

24

Table 10. Effect of year and location on mean burley tobacco yield and quality analyses by location and year.

Treatment Yield(kg ha-1) Quality Index Yeary 2005 2803cx 59.9 2006 3195b 68.8 2007 3405a 75.3 LSD (0.05) 96 Locationw UMRSu 3154b 64.3 MRS river bottom

2983c 76.4

MRS upland 3266a 68.7 LSD (0.05) 95

z The data for 2005 MRS-Lake was missing, no analyses could be performed y Pooled for all locations xLetters within a treatment factor followed by the same letter are not significantly different by the least significant difference (LSD) test (P ≤ 0.05) w Pooled for all years uUMRS = Upper Mountain Research Station; MRS = Mountain Research Station

25

Table 11. Rainfall totals by month, location and yearz.

MRSy (Both Locations) UMRSx

2005

---------------------------cm--------------------------

May 11.1 7.5 June 17.8 17.8 July 16 20.5 August 14.3 14.6 September 2.3 1.9 Season Total 61.5 62.3 2006 May 9.9 8.7 June 12.4 18.8 July 3.5 10.2 August 13.8 9.7 September 14.8 22.1 Season Total 54.4 69.5 2007 May 3 3.9 June 9.8 7.1 July 7.7 6.8 August 9.9 1.75 September 6.9 8.8 Season Total 37.3 28.35

zIrrigation was applied to plots as needed to produce the crop. The amount of water applied is not available. y MRS = Mountain Research Station x UMRS = Upper Mountain Research Station

26

Table 12. Results of combined statistical analyses for all locations and years in the burley tobacco experiment.

Treatment Yield Quality

----------P values--------- Year 0.0001 0.0001Location 0.0001 0.0001Year by Location 0.0001 0.0001

27

Table 13. Effect of cultivar and nitrogen rate on mean burley tobacco yield (kg ha-1) at each site at the upland and river bottom locations of the Mountain Research Station and at the Upper Mountain Research Station in 2005



Tobacco yield (kg ha-1) Mountain Research Station


Upper Mountain

Station Cultivar Clay 403 3604abz 2355cz 2872cz NC 7 3819a 2523bc 3183b KT 204 3791a 2604b 3218b TN 90 3492b 2835a 2872c NC 2000 3682ab 2686ab 3542a Early vs. late maturingx 0.0053y 0.0001y <0.0001y Nitrogen Rate 112 kg N ha-1 3506bz 2169cz 3052a 168 kg N ha-1 3721a 2479b 3124a 224 kg N ha-1 3636ab 2828a 3170a 280 kg N ha-1 3834a 2928a 3208a Linear Contrast 0.0029y <0.0001y 0.0915y Quadratic Contrast 0.9147 0.1087 0.7994 Cubic Contrast 0.0714 0.3202 0.9442

28






Upper Mountain

Station Cultivar Clay 403 3763az 3609az 4000az NC 7 3293a 3092b 3584b KT 204 3399b 3541a 3837ab TN 90 3288b 3115b 3698b NC 2000 3727a 3722a 4000a Early vs. late maturingx 0.5658y 0.2867y 0.5292 y Nitrogen Rate 112 kg N ha-1 3542a 3413baz 3067bz 168 kg N ha-1 3478a 3343ab 3465a 224 kg N ha-1 3541a 3288b 3569a 280 kg N ha-1 3541a 3622a 3558a Linear Contrast 0.3071y 0.2040 y <0.0001y Quadratic Contrast 0.7393 0.0445 0.0066 Cubic Contrast 0.8773 0.4049 0.5852

29






Upper Mountain

Station Cultivar Clay 403 3864 3863bcz 3666az NC 7 3645 3742c 3351b KT 204 3702 4142a 3809a TN 90 3901 4048ab 3595a NC 2000 3898 4178a 3745a Early vs. late maturingx 0.4213y 0.0002y 0.0086 y Nitrogen Rate 112 kg N ha-1 3834abz 3763bz 3383c 168 kg N ha-1 3653b 4031a 3601b 224 kg N ha-1 3707b 4116a 3722ab 280 kg N ha-1 4016a 4100a 3826a Linear Contrast 0.1651y 0.0035 y <0.0001y Quadratic Contrast 0.0129 0.0819 0.4411 Cubic Contrast 0.9611 0.8199 0.8079

30

interaction was observed at any location. A significant early vs. late maturing contrast

(P < 0.01) was observed at five of the nine location/years (Tables 13 through 15).

A significant linear response to N rate (P < 0.004), was observed in five of the

nine location/years (Tables 13 through 15). Burley tobacco yield increased as nitrogen

rate increased. The river bottom location at MRS had a significant linear or quadratic

response (P < 0.05) each year. This location has a sandy loam soil with the greatest

potential for leaching of the three locations. At the river bottom location, burley

tobacco yields were greater in the higher nitrogen rate treatments, indicating that more

nitrogen is needed to obtain optimum yield than the upland location at MRS.

The UMRS has soil with characteristics similar to the soil at the river bottom

location at MRS. Linear contrasts for response to nitrogen rate were significant (P <

0.0001) at UMRS in 2006 and 2007 (Tables 14 and 15) as well as the quadratic

contrast (P = 0.0066) in 2006 (Table 14). The upland location at the MRS has a clay

loam soil with good drainage. Soil at this location would typically not have as much

leaching potential as the soils at the other two locations. A linear response to N rate at

the upland location in 2005 (P = 0.0029) indicated that the lower N rates did not

supply enough N for the yield potential of these burley tobacco cultivars (Table 13). A

quadratic response (P = 0.0129) was observed in 2007 at the same site (Table 15).

This quadratic response indicates that the highest N rate was not needed by the

tobacco plant to make optimum yield that year.

31

Quality Commercial value of tobacco leaf is based on quality. Efforts have been made

to improve leaf quality in tobacco through disease and pest control (Naidu, 2001).

When tobacco companies purchase tobacco from producers, the price paid per pound

of tobacco is based on tobacco leaf quality.

Nitrogen rate had a significant quadratic effect (P < 0.04) on leaf quality at the

UMRS in 2005 and 2006 (Tables 16 and 17). No significant contrasts were observed

at the other trials (Tables 16 through 18) except for a significant cubic contrast (P =

0.0218) at the upland location of the MRS in 2005 (Tables 16). The effect of cultivar

on leaf quality was significant (P = 0.0338) only at the UMRS in 2007 (Table B.9). In

addition, the contrast between early and late maturing types was significant only at the

upland location of the MRS in 2006 (P = 0.015; Table 17). The interaction between

cultivar and N rate was not significant, except at the river bottom location at the MRS

in 2007 (P = 0.0222; Table B.7). When looking at leaf quality by cultivar, it is

important to remember that quality can be reduced by diseases such as blue mold.

Clay’s 403 is a good example of this. At all locations in 2006 and two of the three

locations in 2007, Clay’s 403 had the highest leaf quality. At other year/locations,

Clay’s 403 had much lower quality leaf. The locations that had lower leaf quality

indices had blue mold infections great enough to reduce leaf quality at those

location/years. Blue mold infection rate data to complement this reduced leaf quality

data was taken by plant pathologists, and will be used in a companion paper to show

blue mold infection rate by cultivar and nitrogen rate.

32

Table 16. Effect of cultivar and nitrogen rate on mean burley tobacco quality index at each site at the upland and river bottom locations of the Mountain Research Station and at the Upper Mountain Research Station in 2005

z Letters within a column and within a treatment factor followed by the same letter are not significantly different by Duncan’s multiple range test (P ≤ 0.05). y Values for contrasts represent P values from the F test (Pr > F). x Contrasts for Early vs. late maturing tobacco: Early includes Clay 403, KT 204 and


Tobacco quality index Mountain Research Station


Upper Mountain

Station Cultivar No data Clay 403 69az 49a z NC 7 69a 48a KT 204 72a 46a TN 90 71a 56a NC 2000 69a 51a Early vs. late maturingx 0.4327y 0.2231y Nitrogen Rate 112 kg N ha-1 68bz 56a z 168 kg N ha-1 74a 49ab 224 kg N ha-1 68b 45b 280 kg N ha-1 71ab 49ab Linear Contrast 0.5986y 0.0421y Quadratic Contrast 0.4467 0.0376 Cubic Contrast 0.0218 0.7867

33






Upper Mountain

Station Cultivar Clay 403 66az 77az 76az NC 7 54b 76a 70b KT 204 57ab 77a 72ba TN 90 63ab 77a 70bc NC 2000 57ab 76a 64c Early vs. late maturingx 0.0150y 0.9701y 0.5292 y Nitrogen Rate 112 kg N ha-1 63bz 77a 72a 168 kg N ha-1 73a 76a 74a 224 kg N ha-1 73a 76a 74a 280 kg N ha-1 73a 78a 74a Linear Contrast 0.2583y 0.3524 y <0.0001y Quadratic Contrast 0.5998 0.0619 0.0066 Cubic Contrast 0.6228 0.9932 0.5852

34






Upper Mountain

Station Cultivar Clay 403 77a 76abz 76az NC 7 76a 75b 71ba KT 204 76a 75b 69b TN 90 77a 78a 75a NC 2000 77a 77ab 75a Early vs. late maturingx 0.8158y 0.2427y 0.7348 y Nitrogen Rate 112 kg N ha-1 77a 76a 72a 168 kg N ha-1 76a 76a 73a 224 kg N ha-1 77a 76a 73a 280 kg N ha-1 77a 77a 74a Linear Contrast 0.4788y 0.3163 y 0.4468y Quadratic Contrast 0.3388 0.5122 0.8152 Cubic Contrast 0.7127 0.8174 0.9008

35

Chapter V

Conclusions

Burley yield increased as nitrogen rate increased at the MRS river bottom

location as well as at the upland MRS Location. However, at these two locations

yields at 224 and 280 kg N ha-1 were not significantly different. The current burley

tobacco nitrogen fertilizer rate recommendation is 224 kg N ha-1 (Hoyt, 2008). These

results support this recommendation. In 2006, no significant difference in burley yield

among N rate treatments was observed at the MRS upland location. The MRS river

bottom location did have significant differences in yield, with 280 kg N ha-1 producing

the highest tobacco yield of 3622 kg ha-1. The results were similar at all three locations

in 2007, with the highest yields occurring at the two highest nitrogen rates. As tobacco

yield potential goes up to the 3000 kg ha-1 range, more nitrogen is needed for the

additional biomass (leaf). Yields will be reduced when soil nitrogen is depleted, as

shown by the lower yields at lower nitrogen rates. This could also be attributed to the

greater than normal irrigation needed for these crops due to the dry growing season in

2007 by increasing the amount of soil leaching of nitrogen (Sifola and Postiglione,

2003).

The results of this experiment have demonstrated the importance of nitrogen

fertilization in the production of burley tobacco as shown by yield increases at the two

higher N rates. It is apparent that in tobacco production, nitrogen has an effect on plant

height, time of flowering, crop yield and crop quality. Improved cultivars tested

36

showed similar nitrogen requirements as older cultivars, with soil type playing an

important role in burley tobacco nitrogen recommendations (Waynick et. al, 2006).

Statistical analysis showed that there were few significant (P <0.05) cultivar by

nitrogen rate interactions. The data also indicated that tobacco cultivar and nitrogen

rate play an important role in timing of maturity and tobacco yield. Leaf quality was

affected more by nitrogen rate than cultivar, but only on sandy soils in four

location/years.

Tables 13 through 15 show that the rate of 224 kg N ha-1 produced optimum

tobacco yield. These results support current recommendations for nitrogen fertilizer

application in burley tobacco (Hoyt, 2008). In clay soils, the producer could achieve

acceptable yields at even a lower rate. There was no significant difference between the

224 and the 280 kg N ha-1 rate except in 2007. Therefore producers should avoid over

application of nitrogen fertilizer.

These experiments showed that cultivar selection does play a role in tobacco

yields. Older tobacco cultivars produced yields similar to improved cultivars, but only

in years or locations where foliar or soil diseases did not affect the tobacco plant. The

improved cultivars have been selected for their reduced disease susceptibility (Pearce

et al., 2008). Overall, this experiment showed that the newer burley tobacco cultivars

(TN 90, KT 204, NC 2000, and NC 7) could be fertilized at the recommended 224 kg

ha-1 rate of nitrogen for maximum yield.

37

Literature Cited

38

Literature Cited

Allison, F.E. 1957. Nitrogen and Soil Fertility. Pp.85 – 94. in Soil, The 1957 Yearbook of Agriculture. USDA. Washington, D.C.

Bowman, D.T., R.D. Miller, A.G. Tart, C.M. Sasscer, Jr., and R.C. Rufty. 1989. A

grade index for burley tobacco. Tob Sci. 33:18-19. Brown, B. A. 2008. Situation and Outlook. Pp. 4-9. in 2008 Burley Tobacco

Information. N. C. Cooperative Extension Publication. AG 376. Brown, L.C. and J.W. Johnson. 1991. Ohio State University Extension Fact Sheet

AEX – 463 - 96 Camberato, J.J. 2001. CEC – Everything You Want to Know and Much More.

Clemson University, Clemson, SC. Carrow, R.N., D.V. Waddington and P.E. Rieke. 2001. Turfgrass Soil Fertility and

Chemical Problems. John Wiley & sons, Inc., Hoboken, NJ. Collins, W.K. and S.N. Hawks, Jr.. 1993. Principles of Flue-Cured Tobacco

Production. 1st ed. N.C. State University, Raleigh, NC. Davis, D.L. and Nielsen. 1999. Tobacco: Production, Chemistry, and Technology. Pp.

79. CORESTA, Oxford. Dorn, T. 2001. Nitrogen Sources. University of Nebraska Cooperative Extension. Evanylo, G. K., J. L. Sims and J. H. Grove. 1988. Nutrient Norms for Cured Burley

Tobacco. Agronomy Journal. 80: 610-614. Fisher, L., W.D. Smith and D.S.Whitley. 2008. Variety Information. Pp. 18–22 in:

2008 Burley Tobacco Information. N. C. Cooperative Extension Publication. AG 376.

Flower, K.C.. 1999. Field Practices pp. 76 – 97. In: Layton Davis and Mark

Nielsen. Tobacco Production, Chemistry and Technology. Blackwell, London. Greene, R. E. 1996. The Leaf Sellers, A History of U.S. Tobacco Warehouses: 1619 to

the Present. BAWA, Lexington, KY.

Hiatt, A. J. 1963. Varietal differences in potassium uptake by excised roots of Nicotiana tabacum. Plant and Soil (April 1963). 18:2

39

Hoyt, G. D. and W. L. Hargrove. 1986. Legume cover crops for improving crop and soil management in the southern U. S. HortScience. 21:397-402.

Hoyt, G. D. 2008. Fertilization. pp. 39-46. in: 2008 Burley Tobacco Information.

N. C. Cooperative Extension Publication. AG 376. Ivors, K.L. and P.B. Shoemaker. 2007. Disease Management. Pp. 93 - 116. in 2007

Burley Tobacco Information. N. C. Cooperative Extension Publication. AG 376

Killpack, S.C. and D. Buchholz. 1993. Nitrogen in the Environment: Leaching.

University of Missouri Extension Publication. WQ262. Lewis, R. S., L. R. Linger, M. F. Wolff, and E. A. Wernsman. 2007. The negative

influence of N-mediated TMV resistance on yield in tobacco: linkage drag versus pleiotropy.(Author abstract). TAG Theoretical and Applied Genetics 115.2

Lewis, R. S. and J. S. Nicholson. 2007 Aspects of the evolution of Nicotiana tabacum

L. and the status of the United States Nicotiana Germplasm Collection.(Author abstract). Genetic Resources and Crop Evolution 54.4 (June 2007): 727(14). Academic OneFile. Gale. University of Tennessee Martin. 5 Mar. 2008

Microsoft® Encarta® Online Encyclopedia. 2007 Air. http://encarta.msn.com ©

1997-2007 Microsoft Corporation. All Rights Reserved Miller, R. D. 2005. New Burley Tobacco Varieties Available for 2005 Production.

University of Tennessee, University of Kentucky. Naidu, S.K. 2001. Tobacco: Production, Chemistry and Technology. Crop

Science 41.1 (Jan 2001): 255. Academic OneFile. Gale. University of Tennessee Martin. 5 Mar. 2008

North Carolina Cooperative Extension Service 2008. Burley Tobacco Guide. AG-376.

Published by North Carolina Cooperative Extension Service, College of Agriculture and Life Sciences.

Pearce, B., A. Bailey, G. Palmer, K. Seebold, and B. Miller. 2008. 2008 Guide to

Burley Tobacco Varieties. Pendergrass, W. 1952. Lime, Fertilizer and Manure. University of Tennessee

Extension Service. Publication 336.

40

SAS Institute Inc. 2006. Cary, NC. Internet Website: http://www.sas.com. Shaw, L., D.M. Gossett, and D.F. Tugman. 1965. Dates of Transplanting and the

Probabilities of Spring and Fall Freezes in Relation to the Production of Burley Tobacco Production in Western North Carolina. Pp. 13. N. C. Cooperative Extension Publication. Bulletin 426.

Shelton, J. E. 1987. Fertilization. Pp. 6-10 in: 1987 Burley Tobacco Information.

N. C. Cooperative Extension Publication. AG 376. Sifola, M.I. and L. Postiglione. 2003. The effect of nitrogen fertilization on nitrogen

use efficiency of irrigated and non-irrigated tobacco (Nicotiana tabacum L.). Plant and Soil 252.2 (May 2003): 313. Academic OneFile. Gale. University of Tennessee Martin. 5 Mar. 2008

Smith, W.D. and D.S. Whitley. 2005. Variety Information. Pp. 14–19 in: 2005 Burley

Tobacco Information. N. C. Cooperative Extension Publication. AG 376. Terra Industries Inc.. 2006. UAN Urea Ammonium Nitrate Solution MSDS Number

2040. USDA. 1990. Agricultural Prices, 1989 Summary. Pp. 66-68. National Agricultural

Statistics Service. Vaughan, J.D., G.D. Hoyt, and A.G. Wollum. 2007/2008. Assessment of Burley

Tobacco Nitrogen Needs Following Cover Cropping and Manure Application. Tobacco Science 47:1-10.

Waynick, M.R., H.P. Denton, D.R. Peek, and R.C. Pearce. 2006. Rate and timing of

nitrogen fertilization in burley tobacco. Paper presented at the 42nd Tobacco Workers Conference, 2006.

41

Appendix A

Plot Plans

42

Tab

le A

.1 P

lot p

lan

for

upla

nd lo

catio

n at

Mou

ntai

n R

esea

rch

Stat

ion,

200

7

43

Tab

le A

.2. P

lot p

lan

for

rive

r bo

ttom

loca

tion

at M

ount

ain

Res

earc

h St

atio

n, 2

007

44

Appendix B

ANOVA Tables

45

Table B.1. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the River Bottom Location, Mountain Research Station, 2005.

Percent Flowering Treatment Degrees of

Freedom July 28 August 2

Tobacco Height Tobacco Yield Tobacco Leaf Quality

Cultivar 4 < 0.0001 < 0.0001 < 0.0001 < 0.0001 --z

Nitrogen rate 3 0.6843 0.5580 0.5441 < 0.0001 --

Cultivar by N rate 12 0.1033 0.9246 0.9937 0.7649 -- zThe leaf quality data is unavailable for this location.

46

Table B.2. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the Upland Location, Mountain Research Station, 2005

Percent Flowering Tobacco Height Treatment Degrees of

Freedom August 2 August 11 August 2 August 11

Tobacco Yield

Tobacco Leaf

Quality

Cultivar 4 0.4225 < 0.0001 0.0013 0.0062 0.1345 0.8610

Nitrogen rate 3 0.2032 0.0082 0.2585 0.1624 0.0108 0.0600 Cultivar by N rate 12 0.8666 0.0933 0.1721 0.0557 0.1541 0.4744

47

Table B.3. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the Upper Mountain Research Station, 2005

Treatment Degrees of Freedom

Percent Flowering August 1

Tobacco Height August 1 Tobacco Yield Tobacco Leaf

Quality

Cultivar 4 <0.0001 <0.0001 <0.0001 0.2092

Nitrogen rate 3 0.0225 0.0004 0.4878 0.0520

Cultivar by N rate 12 0.2970 0.4804 0.6209 0.8873

48

Table B.4. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the Bottom Location, Mountain Research Station, 2006


Freedom August 2 August 11 July 21 August 11

Tobacco Yield

Tobacco Leaf Quality

Cultivar 4 <0.0001 < 0.0001 0.0002 0.0045 0.0068 0.7125

Nitrogen rate 3 0.1244 0.2159 0.2863 0.2262 0.1127 0.5372

Cultivar by N rate 12 0.0189 0.5913 0.1088 0.2282 0.5151 0.5330

49




Tobacco Yield


Cultivar 4 0.1036 0.0182 0.0482 0.0802 0.0084 0.1111

Nitrogen rate 3 0.9015 0.9355 0.8162 0.8856 0.9524 0.6444


50


Tobacco Height Treatment Degrees of Freedom

Percent Flowering August 2 July 20 August 3

Tobacco Yield Tobacco Leaf Quality

Cultivar 4 <0.0001 <0.0001 <0.0001 0.0018 0.0870

Nitrogen rate 3 <0.0001 0.0090 0.0003 <0.0001 0.0142

Cultivar by N rate 12 0.1935 0.2250 0.3083 0.7356 0.2481

51

Table B.7. Significance (P values) of cultivar, nitrogen rate and cultivar by nitrogen rate interaction on percent flowering, height, yield, and quality of burley tobacco at the River Bottom Location, Mountain Research Station, 2007


Freedom August 7 August 13 July 20 July 25

Tobacco Yield


Cultivar 4 <0.0001 <0.0001 0.0004 0.0009 0.0198 0.0562

Nitrogen rate 3 0.0736 0.3148 0.1656 0.3822 0.0110 0.6922


52



Freedom August 10 August 20 July 25 July 30

Tobacco Yield


Cultivar 4 0.0044 <0.0001 0.0003 0.0042 0.1810 0.6849

Nitrogen rate 3 0.2337 0.7398 0.6357 0.2707 0.0616 0.6834


53




Tobacco Yield


Cultivar 4 <0.0001 0.0007 0.1217 0.0841 0.0037 0.0338

Nitrogen rate 3 0.9937 0.3545 0.8442 0.5870 0.0016 0.8938


54

Appendix C

Weather Data

55

Table C.1. Weather Data Laurel Springs, NC May 2005

56

Table C.2. Weather Data Laurel Springs, NC June 2005

57

Table C.3. Weather Data Laurel Springs, NC July 2005

58

Table C.4. Weather Data Laurel Springs, NC August 2005

59

Table C.5. Weather Data Laurel Springs, NC September 2005

60


61


62


63


64


65


66


67


68


69


70

Table C.16. Weather Data Waynesville, NC May 2005

71

Table C.17. Weather Data Waynesville, NC June 2005

72

Table C.18. Weather Data Waynesville, NC July 2005

73

Table C.19. Weather Data Waynesville, NC August 2005

74

Table C.20. Weather Data Waynesville, NC September 2005

75


76


77


78


79


80


81


82


83


84


85

Vita

David Kaleb Rathbone was born in Waynesville, NC on March 16, 1983. He

graduated from Tuscola High School in 2001. In 2006 he graduated from The

University of Tennessee with a B.S. in Environmental and Soil Sciences with a

concentration in Agricultural Systems Technology and a Minor in Biosystems

Engineering Technology. Kaleb is currently employed by the North Carolina

Department of Agriculture at the Mountain Research Station as a Tobacco Research

Specialist.

Documents

Effect of Nitrogen Rate and Cultivar on Burley Tobacco · 2013-06-06 · tobacco growers with recommendations for application of nitrogen fertilizer to newer cultivars. The effect