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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.
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
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
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.
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.