The Purpose of a Fertilizer is to Supply Nutrients.

Tobacco Fertilization

• Not only important for optimum yield, but extremely important for quality

• Ripenning of tobacco is caused by N starvation

• Begins with the bottom leaves (same as N deficiency) and moves up the stalk

• Proper fertilization is key to ripenning

Fertilization Principles

• Understand the nutrient needs of the plant.

• Know the level of nutrients supplied by the soil.

• Use fertilizers to supply the difference.

• Lime to the optimum pH.

Soil Testing

• Before any fertilizer is applied

• P index

• K index

• pH

Effect of pH on Nutrient Availability

Troug, 1948

The pH of Tobacco Soils in the Coastal Plain and Piedmont

0

5

10

15

20

25

30

35

40

45

0-4.9 5-5.4 5.5-5.9 6.0-6.4 6.5+

Coastal PlainPiedmont

2002

Recommended pH

• For Tobacco Soils– 5.8 to 6.2

Essential Elements

• Carbon, Hydrogen, Oxygen

• Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, Sulfur, Chloride

• Boron, Manganese, Iron, Zinc, Copper, and Molybdenum

Nutrient Removal by a 2000 Pound Tobacco Crop

Nutrient Pounds/Acre

Nitrogen 70

Phosphorus 12

Potassium 80

Calcium 55

Magnesium 22

Sulfur 18

McCants and Woltz

Nutrient Removal by a 2000 Pound Tobacco Crop

Nutrient Pounds/Acre

Boron 0.07

Manganese 0.7

Iron Trace

Zinc Trace

Copper 0.04

Molybdenum Trace

McCants and Woltz

Fertilization Principles(The Five R’s)

• Apply the right nutrient,

• at the right rate,

• at the right time,

• in the right place,

• at the right cost.

Effect of Base Fertilizer Application Methods on Yield

2200

2220

2240

2260

2280

2300

2320

2340

2360

Lb/A

Brdcast 1 Bd Deep 2 Bd/Trans 2 Bd/7-10D

Application Method

Yield

64 OFT, 1972-79WKC and SNH

Proper Timing, Rate, and Placement of Nutrients

• Increases uptake efficiency by:– Minimizing leaching of mobile nutrients such

as nitrogen.– Minimizing fixation of nutrients such as

potassium and phosphorus in certain soils.

• Reduces pollution of ground and surface waters through increased uptake by plants.

Soil Nitrate Levels With 150 lbs N Applied in 1 Application

0 5 10 15 20 25

12 Weeks

8 weeks

4 Weeks

Wee

ks A

fter

Tra

nspl

anti

ng

Soil Nitrate (PPM)

0-15 cm16-30 cm31-45 cm46-60 cm61-75 cm

Smith, 1980

Soil Nitrate Levels With 150 lbs N Split Over 3 Applications

0 5 10 15 20 25

12 Weeks

8 weeks

4 Weeks

Tim

e A

fter

Tra

nspl

anti

ng

Soil Nitrate (PPM)

0-15 cm16-30 cm31-45 cm46-60 cm61-75 cm

Smith, 1980

Effect of Application Number on Tobacco Value

660068007000720074007600780080008200840086008800

1 2 3 4 5

Number of Nitrogen Sidedressings

$/H

a

Value

Smith, 1980

Nitrogen

The Most Important Nutrient Affecting Yield and Quality

As Nitrogen Rate Increases

• Yield increases to a point then decreases.

• Leaf size increases, but leaf thickness (body) decreases.

• Total alkaloids increase and sugars decrease in cured leaf.

• Maturity and ripening are delayed.

• Cured-leaf color darkens.

As Nitrogen Rate Increases

• Sucker growth increases and control decreases.

• Leaf drop and leaf break increase.

• Hornworm and aphid populations increase.

• Blue Mold losses are more severe.

Effect of Nitrogen Rate on Quality

Quality Factor

N Rate 1 2 3

-------------Percent---------------

Low 30 70 0

Rec. 25 73 2

Excess 19 64 17

Suggested Base Nitrogen Rates Based on Topsoil Depth

Topsoil DepthInches (cm)

Nitrogen Ratelb/a (kg/ha)

5 (13) 50 (56)

10 (25) 60 (67)

15 (38) 70 (78)

20+ (51) 80 (90)

Maturity vs. Ripeness

• Maturity– When a leaf reaches maximum size and weight.– A function of leaf age (time in the field).

• Ripeness– A function of nitrogen metabolism (uptake).– A leaf will not ripen until nitrogen uptake is

nearly zero.– A nitrogen starvation process.

Nitrate Reduction and Starch Accumulation- Ideal Conditions

Nitrate Reduction and Starch Accumulation- Delayed N Uptake

Nitrate Reduction and Starch Accumulation- Restricted N Uptake

Ammonium vs. Nitrate N Sources

• Lower yields when N absorbed primarily in ammonium form.

• Response to ammonium in the fertilizer is related to nitrification rate.

• Nitrification rate is slower when:– Soil pH is low.– Soil moisture is low.– Low soil temperature.

Ammonium vs. Nitrate N Sources

• Recommendations for North Carolina conditions.– As long as pH is correct, N source will not

affect yield and quality

• Calcium nitrate, Potassium Nitrate, Ammonium Nitrate, Urea, 30% UAN, 24%S etc.

Fertilization

• Greater than 90% of tobacco soils in North Carolina have a high or very high phosphorus index

• No phosphorus needed to produce tobacco• NC average is about 65 lbs P per acre• Agronomically and Environmentally sound

practice to eliminate or reduce P use• GAP

Fertilization

• If no or low P is needed then it could possibly reduce fertilizer costs

• Definitely opens the door for additional sources and application methods of N and K

Effect of Fertilizer Treatment on Tobacco Value 2004-05

0

1000

2000

3000

4000

5000

6000

7000

Value ($/A)

Dup 04Roc

k 04CCRS 04

UCPRS 04O

ns 05

UCPRS 05CCRS 05 Avg

6-6-18/15.5-0-00-0-22/15.5-0-0

Effect of Fertilizer Treatment on Tobacco Value 2005

0500

10001500200025003000350040004500

Value ($/A)

Onslo

w

UCPRS

CCRS

AVG

6-6-18/15.5-0-06-3-18/15.5-0-00-0-22 Band/CN-90-0-22 Bdcst/CN-9

Fertilization

• Even though there is no yield response to P application on high P soils there may an early growth response

• Especially under cool, wet conditions immediately following transplanting

• Ability of a small root system to “find” phosphorus if none is applied in fertilizer

Effect of Fertilizer Treatment on Flowering 2005

0

5

10

15

20

25

30

35

40

62 66 70 76

Days After Transplanting

Flo

wer

s/P

lot

6-6-18/15.5-0-0

6-3-18/15.5-0-0

0-0-22/15.5-0-0

0-0-30/30%UAN/TPW

UCPRS

Fertilization

• Same early growth response from 20 lbs of P from 6-3-18 or 5 lbs of P in the transplant water

• Allows for a significant reduction in P application without affecting early season growth

• Allows for alternative K sources • Allows for 100% of N to be supplied from a N

only product

Nitrogen Study

• Two LocationsKinston and Oxford

• Three SourcesAmmonium NitrateCalcium Nitrate30% UAN

• Rates0, 20, 40, 60, 80 (lb/A) - 2004100, 120 (lb/A) – added in 2005

Effect of N Rate on Tobacco Yield and Value at LCPRS

2000

3000

4000

5000

0 20 40 60 80

Nitrogen Rate (lb/A)

lbs.

or

$/A

YieldValue

2004

*

*

Effect of N Rate on Tobacco Yield and Value at LCPRS

2000

2500

3000

3500

4000

4500

5000

0 20 40 60 80 100 120

Nitrogen Rate (lb/A)

lbs.

or

$/A

YieldValue

2005

*

*

Fertilization

• Avoid K and N sources that contain more than 20-30 lbs of Cl per acre

• State Law limits Cl levels in “tobacco grade” fertilizers

• Only small amounts of KCl are acceptable

• K Mag

• Sulfate of Potash

Fertilizer Selection

• Choose ratio based on soil test P.– 0 Lb/A: 1-0-3 (8-0-24), 0-0-1 (0-0-30, 0-0-22)– 1-40 Lb/A: 1-1-3 (6-6-18, 8-8-24)– 41-80 Lb/A: 1-2-3 (4-8-12, 6-12-18)– 81+ Lb/A: 1-3-3 (3-9-9, 6-18-18)

• Apply at the rate to supply all of the P recommended and no more than 40 Lb N/A.

Fertilizer Selection

• Additional N from a sidedresser

• Use N/K sidedresser if additional K is needed. 15-0-14, 13.5-0-14

Nitrogen Applications to Partially Drowned Tobacco

25002600270028002900300031003200330034003500

$/A

0 15 30

Nitrogen Rate (Lb/A)

Value

Peedin,2 Loc., 1995

Effect of Fertilizer Addition to Partially Drowned Tobacco

25002600270028002900300031003200330034003500

$/A

None 16-0-0BC-OT

30%,WB-RM

15-0-14 BC-OT

8-0-11BC-OT

Fertilizer Treatment

Value

Peedin,2 Loc., 1995

Organic Nitrogen

• Undesirable for tobacco– Organic N not adsorbed by roots. Must undergo

mineralization prior to uptake.– Mineralization rate is unpredictable.

• Makes rate determination difficult.

• Usually too slow, and contributes to late-season N uptake. Delays ripening.