Topping

Why does a plant have leaves?

As a store for seed productionAs a store for seed production

Historical Perspective

Late topping/ full Late topping/ full bloombloom Past DemandPast Demand

Lighter bodied Lighter bodied style of tobaccostyle of tobacco

Milder tasteMilder tasteNon-filteredNon-filtered

Sucker controlSucker controlHand removalHand removalNo chemical No chemical

controlcontrol

Physiological Aspect of Topping

Leaf SpreadLeaf Spread Removal of non-beneficial nutrient sinkRemoval of non-beneficial nutrient sink Root stimulationRoot stimulation

Timing Best when 10-25% of Best when 10-25% of

plants have one flower plants have one flower openopen Effects on plantEffects on plant

Darker cured leaf colorDarker cured leaf color Prior to physiological Prior to physiological

maturitymaturityPrior to stalk Prior to stalk

hardeninghardening Increases root Increases root

developmentdevelopmentMore leaf expansion in More leaf expansion in

lower part of plantlower part of plant

Yield Trends Bud ToppingBud Topping

Yield loss in many varietiesYield loss in many varieties Good for late maturing varietiesGood for late maturing varieties

10-25%10-25% Best for most varietiesBest for most varieties Good qualityGood quality

50-75%50-75% Suckers initiated in some varietiesSuckers initiated in some varieties

100%+100%+ Yield declineYield decline Sucker initiation in all varietiesSucker initiation in all varieties Opportunistic diseasesOpportunistic diseases SenescenceSenescence

Disease Incidence Hollow StalkHollow Stalk

Late TopLate Top Harden StalkHarden Stalk Ragged TopRagged Top

Effects of Topping Time on Yield

504 553 570 579

1666 1755 1729 1657

625 631 594 604

2795 2958 2876 2840

0

500

1000

1500

2000

2500

3000

Bud 10-25% 50-75% 100%

Bloom Stage

Yie

ld l

b/a

12 trials over 10 years

Topping Height Root systemRoot system

Supports a finite leaf yield Supports a finite leaf yield Leaf numberLeaf number

20 leaves20 leavesLarger leavesLarger leavesYieldYield

• Highest sometimesHighest sometimes 26 leaves26 leaves

Smaller leavesSmaller leavesYieldYield

• No different most timesNo different most times

Effects of Topping Time on Yield

608 612 586 598 625 630

1374 1442 1368 1421 1451 1390

686 701 710 703 686 676

2668 2755 2664 2722 2763 2697

0

500

1000

1500

2000

2500

3000

20 26 - Bud 10-25% 50-75% 100%

Leaf Number Bloom Stage

Yie

ld l

b/a

17 trials over 9 years

Effects of Topping Time on Leaf Yield

8.286.58 7.32 7.45 7.57 7.38

0

2

4

6

8

10

20 26 - Bud 10-25% 50-75% 100%

Leaf Number Bloom Stage

Yie

ld g

/lea

f

17 trials over 9 years

Topping Study Labor ComparisonsLawrence Co. – Malcom Smith Farm

465 432

703 678

495 577

784 778

2447 2465

0

500

1000

1500

2000

2500

20 26

Leaf Number

Yie

ld l

b/a

Topping Study Labor ComparisonsLawrence Co. – Malcom Smith Farm

19.3333.83

154.67

203.00

21.1336.40

169.07

218.39

0

50

100

150

200

250

Cut hr/a Strip hr/a Cut Cost/a Strip Cost/a

20

26

On a Larger Scale

6 leaves per plant6 leaves per plant 42,000 per acre42,000 per acre

Based on7000 populationBased on7000 population 420,000420,000

Based on 10 acresBased on 10 acres 1,035,0001,035,000

Based on 24 acresBased on 24 acres

Maturity Approximately 4 weeks Approximately 4 weeks

after toppingafter topping Influenced by residual NInfluenced by residual N SignsSigns

White stem & stalkWhite stem & stalk Leaf cracks when bentLeaf cracks when bent Bronzing of leavesBronzing of leaves

Harvesting

TimingTiming Yield Yield

Increase to 4- 5 wks after toppingIncrease to 4- 5 wks after toppingDecrease after 5 wks after toppingDecrease after 5 wks after topping

Quality Quality High early increase slightly to 3 wks High early increase slightly to 3 wks

after toppingafter toppingDecline after 3 wks Decline after 3 wks

Effects of Harvest Date on Yield and Quality

1500

2000

2500

3000

2 3 4 5 6

Weeks after Transplanting

0

20

40

60

80

100Quality

Yield

Harvest Date Across Five Locations

616 660 706 696 738

1201 13461524 1448 1364

451448

460 499 524

2268 2454 2690 2643 2626

0

500

1000

1500

2000

2500

3000

2 3 4 5 6

Yie

ld l

b/a

HSD 0.05 = 74 168 55 201Locations = Bath, Boyle, Clay, Jackson & Pulaski

Effects of Harvest Time on QualityJackson Co. - Harry Nicholson Farm

0

2

4

6

8

10

Qu

alit

y (0

-10)

10

bes

t

FLYINGS 6 5.25 4.25 3.75 3.5

LUGS 5.75 5.5 4.5 3.75 3.75

LEAF 5 4 3.75 3.5 3.5

AVERAGE 5.58 4.92 4.17 3.67 3.58

2 3 4 5 6

HSD 0.05 = 1.74 1.99 1.95 1.59 6 = Usable Tobacco, 4 to 5 = Marginal, 4 = Non-usable,

3 was described as high color, undesirable, tight faced & immature