Post on 01-Apr-2015
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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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