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Trellised Tomatoes Trellised Tomatoes and Drip Irrigationand Drip Irrigation

Bill Yarborough NCDA&CS

Agronomic Division

SE Vegetable & Fruit Expo

December 2009

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NCDA&CS Agronomic NCDA&CS Agronomic Division ServicesDivision Services

• Plant / Waste / Solution/ Media Analyses

• Soil Testing

• Nematode Assay

• Field Services

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Field Services Field Services — 13 regions— 13 regions

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NCDA&CS Soil TestingNCDA&CS Soil Testing

• Measures soil pH and acidity

• Measures nutrient reserves

• Recommends lime application rates

• Recommends fertilizer rates

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NCDA&CSNCDA&CS Plant Tissue Analysis Plant Tissue Analysis

• Measures nutrient concentrations

• Monitors nutrient uptake

• Finds deficiencies

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Plant AnalysisPlant Analysis

• Sample latest mature, fully extended compound leaf.

• Sample weekly, beginning when first fruit is the size of a dime.

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Talk TodayTalk Today

• History of tomato production in WNC

• Major nutrients discussed

• Fertility recommendations

• Contributors — Dr. Greg Hoyt (NCSU) and Steve Dillon (NCDA&CS)

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History of Tomatoes History of Tomatoes in Western NCin Western NC

• Early 1950s

• Staked tomatoes

• Research on fertility based on high rates of nitrogen and little to no irrigation

• Use of trellises began in late 1960s

• Drip irrigation began in the 1980s

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NitrogenNitrogen

• Important for vegetative growth

• Trellis varieties determinant

• Excessive N can be a concern

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NitrogenNitrogen

• Apply 40–60 lb/acre preplant.

• Meet additional needs, as required, with drip.

• Apply total of 90–130 lb/acre over the entire season.

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PhosphorusPhosphorus

• Important for early growth

• Soil test recommendations . . . . Can these be reduced?

• Preplant application sufficient

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%P and P-Index

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9

Week

P I

nd

ex

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

P (

%) Carolina Gold (P-I)

Floralina (P-I)

Carolina Gold (% P)

Floralina (% P)

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P 1998-2000

2000

y = 0.3368e-0.0626x

R2 = 0.6327

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

1 2 3 4 5 6 7 8 9

Week

P %

1999

1998

2000

Expon. (2000)

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Potassium (K)Potassium (K)

• Critical for fruit quality

• Preplant application insufficient

• Application through drip essential

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Potassium Concentration

0

0.5

1

1.5

2

2.5

3

3.5

4

1 2 3 4 5 6 7 8 9

Week

K %

Carolina Gold

Floralina

Roma

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K ConsiderationsK Considerations

• K levels will be 4% ppm early in season.

• K 2.5–3% is desirable at harvest.

• K 2% produces soft fruit.

• K 1% is unharvestable.

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CalciumCalcium

• Important for blossom-end rot control

• Soil test recommendations adequate

• Adequate soil water essential

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Calcium Concentration

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

1 2 3 4 5 6 7 8 9

Week

Ca

% Carolina Gold

Floralina

Roma

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Blossom-end Rot Blossom-end Rot and Controland Control

• Foliar sprays ineffective

• Consider gypsum

• Adequate soil water essential

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BoronBoron

• Important for potassium uptake

• Preplant application insufficient

• Postplant applications required

• Can be applied foliar or drip

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Boron Concentration

020406080

100120

1 2 3 4 5 6 7 8 9

Week

B p

pm

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Preplant Preplant RecommendationsRecommendations

for Trellised Tomatoesfor Trellised Tomatoes

• Soil test.

• Apply P2O5, potassium, boron and lime as recommended.

• Apply up to 60 lb/acre of N preplant.

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N & K Drip FertilityN & K Drip Fertility Recommendations Recommendations

• Begin applying fertilizer when fruit is about the size of a dime.

• Apply 13-0-44 (or equivalent) at a rate of 20–25 lb/acre/wk.

• Two weeks before first harvest, increase rate to 50 lb/acre/wk.

• Once 50% of crop is harvested, begin reducing rate.

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N & K Fertilization N & K Fertilization in Drip-irrigation systemin Drip-irrigation system

Time of Application N (lb/A) K (lb/A)

Preplant 40–70 If deficient

1 wk > 1st fruit set (~ 30 days > planting)

3–4 / wk 10–12 / wk *

2 wks < harvest 6–7 / wk 20–25 / wk

Halfway into harvest 3–4 / wk 10–12 / wk

Approx. season total 90–130 170–205

* 13-0-44 used to apply K and N in 3-to-1 ratio

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Other Fertility Other Fertility ConsiderationsConsiderations

• Low P2O5 levels at harvest should not be a concern.

• Calcium levels should not be a concern with drip irrigation.

• Boron levels should be between 40–75 ppm throughout harvest.

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Quality Fruit Begins Quality Fruit Begins with Careful Fertilitywith Careful Fertility

• Follow soil test recommendations.

• Use plant analysis for monitoring.

• Adequate water is essential.

• Monitor key elements boron and potassium.

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Trellised Tomatoes Trellised Tomatoes and Drip Irrigationand Drip Irrigation

Bill Yarborough NCDA&CS

Agronomic Division

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