Trellised Tomatoes and Drip Irrigation SE Vegetable & Fruit Expo December 2009 Bill Yarborough NCDA&CS Agronomic Division

NCDA&CS Agronomic Division Services Plant / Waste / Solution/ Media Analyses Soil Testing Nematode Assay Field Services

Field Services — 13 regions

NCDA&CS Soil Testing Measures soil pH and acidity Measures nutrient reserves Recommends lime application rates Recommends fertilizer rates

NCDA&CS Plant Tissue Analysis Measures nutrient concentrations Monitors nutrient uptake Finds deficiencies

Plant Analysis Sample latest mature, fully extended compound leaf. Sample weekly, beginning when first fruit is the size of a dime.

Talk Today History of tomato production in WNC Major nutrients discussed Fertility recommendations Contributors — Dr. Greg Hoyt (NCSU) and Steve Dillon (NCDA&CS)

History of Tomatoes in 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

Nitrogen Important for vegetative growth Trellis varieties determinant Excessive N can be a concern

Nitrogen Apply 40–60 lb/acre preplant. Meet additional needs, as required, with drip. Apply total of 90–130 lb/acre over the entire season.

Phosphorus Important for early growth Soil test recommendations . . . . Can these be reduced? Preplant application sufficient

Potassium (K) Critical for fruit quality Preplant application insufficient Application through drip essential

K 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.

Calcium Important for blossom-end rot control Soil test recommendations adequate Adequate soil water essential

Blossom-end Rot and Control Foliar sprays ineffective Consider gypsum Adequate soil water essential

Boron Important for potassium uptake Preplant application insufficient Postplant applications required Can be applied foliar or drip

Preplant Recommendations for Trellised Tomatoes Soil test. Apply P2O5, potassium, boron and lime as recommended. Apply up to 60 lb/acre of N preplant.

N & K Drip Fertility 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.

N & K Fertilization in 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 10–12 / wk Approx. season total 90–130 170–205 * 13-0-44 used to apply K and N in 3-to-1 ratio

Other Fertility Considerations 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.

Quality Fruit Begins with Careful Fertility Follow soil test recommendations. Use plant analysis for monitoring. Adequate water is essential. Monitor key elements boron and potassium.

Trellised Tomatoes and Drip Irrigation Bill Yarborough NCDA&CS Agronomic Division

For more information, browse the Agronomic Division Web site www.ncagr.gov/agronomi/