7 Plant Analysis Sample latest mature, fully extended compound leaf. Sample weekly, beginning when first fruit is the size of a dime.
8 Talk Today History of tomato production in WNC Major nutrients discussed Fertility recommendations Contributors — Dr. Greg Hoyt (NCSU) and Steve Dillon (NCDA&CS)
9 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
11 Nitrogen Important for vegetative growth Trellis varieties determinant Excessive N can be a concern
12 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.
13Phosphorus Important for early growth Soil test recommendations.... Can these be reduced? Preplant application sufficient
16 Potassium (K) Critical for fruit quality Preplant application insufficient Application through drip essential
19 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.
20 Calcium Important for blossom-end rot control Soil test recommendations adequate Adequate soil water essential
23 Blossom-end Rot and Control Foliar sprays ineffective Consider gypsum Adequate soil water essential
24 Boron Important for potassium uptake Preplant application insufficient Postplant applications required Can be applied foliar or drip
26 Preplant Recommendations for Trellised Tomatoes Soil test. Apply P 2 O 5, potassium, boron and lime as recommended. Apply up to 60 lb/acre of N preplant.
27 N & K Drip Fertility Recommendations Begin applying fertilizer when fruit is about the size of a dime. Apply (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.
28 N & K Fertilization in Drip-irrigation system Time of ApplicationN (lb/A)K (lb/A) Preplant40–70If deficient 1 wk > 1 st fruit set (~ 30 days > planting) 3–4 / wk10–12 / wk * 2 wks < harvest6–7 / wk20–25 / wk Halfway into harvest3–4 / wk10–12 / wk Approx. season total90–130170–205 * used to apply K and N in 3-to-1 ratio
29 Other Fertility Considerations Low P 2 O 5 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.
30 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.
31 Trellised Tomatoes and Drip Irrigation Bill Yarborough NCDA&CS Agronomic Division
32 For more information, browse the Agronomic Division Web site