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Renewed Interest in Blueberry N Sources for North Carolina Production

Renewed Interest in Blueberry N Sources for North Carolina Production. SERA 6 Annual Meeting June 14, 2010. David H. Hardy NCDA&CS Agronomic Division. Today’s Presentation. General overview of production Standard fertilizer program Fertility interests to pursue

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Renewed Interest in Blueberry N Sources for North Carolina Production

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  1. Renewed Interest in Blueberry N Sources for North Carolina Production SERA 6 Annual Meeting June 14, 2010 David H. Hardy NCDA&CS Agronomic Division

  2. Today’s Presentation • General overview of production • Standard fertilizer program • Fertility interests to pursue • Challenges in blueberry fertility • Overview of 2009 study • Future work

  3. N.C. Blueberries 4,200 acres $3.7 million in 2007 4th largest producer in U.S. 5th highest yield in U.S.— 5430 lb/A

  4. N.C. Highbush & Rabbiteye — 80% Highbushconcentrated in Bladen, Pender Duplin, & Sampson counties

  5. Preferred Soil pH Levels  Highbush 4.0–5.0 Rabbiteye 4.5–5.3 Dr. George Cummings, 2005 N.C. Blueberry Council Proceedings

  6. Soil types in southeastern NC may vary greatly and have a major fertility impact.

  7. Nitrogen and phosphorusare the twomost importantnutrients.

  8. The micronutrient copperis often deficient.

  9. Standard Fertilizer Program • 14-28-14 @ bud break about mid-March • 100 to 150 lb per acre • 14-28-14 in early May • 75 lb per acre • 18-46-0 (DAP) in late July or early August • 50 lb per acre

  10. Standard Fertilizer Program • Developed from work of Cummings • Older varieties • Successful and well adopted • Fertilizer relatively inexpensive

  11. Grower Interest in Fertility • Newer variety responses to fertilizer • Star, Duke, Reveille, O’Neal

  12. Grower Interest in Fertility Newer variety responses to fertilizer Star, Duke, Reveille, O’Neal Possible benefit from N during fruiting

  13. Grower Interest in Fertility Newer variety responses to fertilizer Star, Duke, Reveille, O’Neal Possible benefit from N during fruiting Better use of liquid vs. dry fertilizer 5-10-5 liquid 6-12-6 liquid

  14. Challenges in Fertility Work • Blueberry is a perennial plant • Plant takes up N in one season • Response may take several seasons • Application of fertilizer during fruiting may dislodge berries from plant • Slow release N to avoid this

  15. Challenges in Fertility Work • Blueberries are grown on mineral and organic soils • Range of N from organic matter Leon Lynn Haven Murville Pamlico

  16. Challenges in Fertility Work • Low soil pH may affect soil N reactions • Conversion to nitrate • Where does N go???

  17. Blueberry N Use & Source • Fairly inefficient in using N • Ammonium (NH4+) preferred over nitrate (NO3-) • Mostly ammonium N in 14-28-14 • Studies showing higher yields with sulfur-coated urea

  18. Research Objective in 2009 • Evaluate plant nutrition and overall plant growth • Standard dry and liquid grower fertilizers • Slow-release N products • Mixed with P and K sources to give similar rates of all nutrients

  19. Research 2009 • Castle Hayne Station • 7 fertility treatments per row • (6 plants / treatment) • Duke, O-Neal, Star varieties • 2 rows of each variety for total of 6 rows • Variety / row = replications

  20. Research in 2009 (7 treatments) • Control (no fertilizer) • Standard fertility (dry 14-28-14 & 18-46-0) • 5-10-5 liquid (increase efficiency by placement) Slow-release N treatments (potential increase in N availability during fruiting) • Urea • Sulfur-coated urea • Nitamin 30L (urea polymer, triazone, liquid N) • Florikan (13-13-17, 92% polymer-coated NH4+ & NO3-)

  21. Fertilizers 14-28-14 Urea Sulfur-coated Urea Florikan

  22. Research 2009 • Soil sampled for nitrate and fertility • 4 times (Mar 26, May 4, Jun 26, Aug 5) • Plant tissue sampled • Jun 26 • Growth • Oct 29 — measurements (H × W) • Dec 22 — pictures

  23. Results

  24. Soil Fertility in Top 12 Inches • Appears to be no differences in treatments for a given depth • Note P differences between depths

  25. Plant Nutrient Levels

  26. Sufficiency Plant Nutrient Levels

  27. Growth as Affected by Treatment

  28. Replications of Star Urea Gr. Std Dry Gr. Std Liquid S-Coated Urea Nitamin Florikan Check Urea Gr. Std Dry Gr. Std Liquid S-Coated Urea Nitamin Florikan Check

  29. Replications of O’Neal Urea Gr. Std Dry Gr. Std Liquid S-Coated Urea Nitamin Florikan Check Urea Gr. Std Dry Gr. Std Liquid S-Coated Urea Nitamin Florikan Check

  30. Replications of Duke Gr. Std Dry Gr. Std Liquid Urea S-Coated Urea Nitamin Florikan Check Gr. Std Dry Gr. Std Liquid S-Coated Urea Urea Nitamin Florikan Check

  31. Thoughts on the Study One-year of data No conclusions can be drawn Considerable variability in plant growth Treatments look promising Differences may become more pronounced over the next few years Soil nitrate data puzzling Soil heavily amended with pine bark

  32. Further Studies • Expand this study to grower fields on different soil types • Implement incubation studies in glass flasks with sampling intervals to determine N reactions at low pH • Study rock phosphate • Potential slow release of P on organic soils

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