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The Purpose of a Fertilizer is to Supply Nutrients.

The Purpose of a Fertilizer is to Supply Nutrients. Tobacco Fertilization. Not only important for optimum yield, but extremely important for quality Ripenning of tobacco is caused by N starvation Begins with the bottom leaves (same as N deficiency) and moves up the stalk

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The Purpose of a Fertilizer is to Supply Nutrients.

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  1. The Purpose of a Fertilizer is to Supply Nutrients.

  2. Tobacco Fertilization • Not only important for optimum yield, but extremely important for quality • Ripenning of tobacco is caused by N starvation • Begins with the bottom leaves (same as N deficiency) and moves up the stalk • Proper fertilization is key to ripenning

  3. Fertilization Principles • Understand the nutrient needs of the plant. • Know the level of nutrients supplied by the soil. • Use fertilizers to supply the difference. • Lime to the optimum pH.

  4. Soil Testing • Before any fertilizer is applied • P index • K index • pH

  5. Effect of pH on Nutrient Availability Troug, 1948

  6. The pH of Tobacco Soils in the Coastal Plain and Piedmont 2002

  7. Recommended pH • For Tobacco Soils • 5.8 to 6.2

  8. Essential Elements • Carbon, Hydrogen, Oxygen • Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, Sulfur, Chloride • Boron, Manganese, Iron, Zinc, Copper, and Molybdenum

  9. Nutrient Removal by a 2000 Pound Tobacco Crop McCants and Woltz

  10. Nutrient Removal by a 2000 Pound Tobacco Crop McCants and Woltz

  11. Fertilization Principles(The Five R’s) • Apply the right nutrient, • at the right rate, • at the right time, • in the right place, • at the right cost.

  12. Effect of Base Fertilizer Application Methods on Yield 64 OFT, 1972-79 WKC and SNH

  13. Proper Timing, Rate, and Placement of Nutrients • Increases uptake efficiency by: • Minimizing leaching of mobile nutrients such as nitrogen. • Minimizing fixation of nutrients such as potassium and phosphorus in certain soils. • Reduces pollution of ground and surface waters through increased uptake by plants.

  14. Soil Nitrate Levels With 150 lbs N Applied in 1 Application Smith, 1980

  15. Soil Nitrate Levels With 150 lbs N Split Over 3 Applications Smith, 1980

  16. Effect of Application Number on Tobacco Value Smith, 1980

  17. Nitrogen The Most Important Nutrient Affecting Yield and Quality

  18. As Nitrogen Rate Increases • Yield increases to a point then decreases. • Leaf size increases, but leaf thickness (body) decreases. • Total alkaloids increase and sugars decrease in cured leaf. • Maturity and ripening are delayed. • Cured-leaf color darkens.

  19. As Nitrogen Rate Increases • Sucker growth increases and control decreases. • Leaf drop and leaf break increase. • Hornworm and aphid populations increase. • Blue Mold losses are more severe.

  20. Effect of Nitrogen Rate on Quality

  21. Suggested Base Nitrogen Rates Based on Topsoil Depth

  22. Maturity vs. Ripeness • Maturity • When a leaf reaches maximum size and weight. • A function of leaf age (time in the field). • Ripeness • A function of nitrogen metabolism (uptake). • A leaf will not ripen until nitrogen uptake is nearly zero. • A nitrogen starvation process.

  23. Nitrate Reduction and Starch Accumulation- Ideal Conditions

  24. Nitrate Reduction and Starch Accumulation- Delayed N Uptake

  25. Nitrate Reduction and Starch Accumulation- Restricted N Uptake

  26. Ammonium vs. Nitrate N Sources • Lower yields when N absorbed primarily in ammonium form. • Response to ammonium in the fertilizer is related to nitrification rate. • Nitrification rate is slower when: • Soil pH is low. • Soil moisture is low. • Low soil temperature.

  27. Ammonium vs. Nitrate N Sources • Recommendations for North Carolina conditions. • As long as pH is correct, N source will not affect yield and quality • Calcium nitrate, Potassium Nitrate, Ammonium Nitrate, Urea, 30% UAN, 24%S etc.

  28. Fertilization • Greater than 90% of tobacco soils in North Carolina have a high or very high phosphorus index • No phosphorus needed to produce tobacco • NC average is about 65 lbs P per acre • Agronomically and Environmentally sound practice to eliminate or reduce P use • GAP

  29. Fertilization • If no or low P is needed then it could possibly reduce fertilizer costs • Definitely opens the door for additional sources and application methods of N and K

  30. Effect of Fertilizer Treatment on Tobacco Value 2004-05

  31. Effect of Fertilizer Treatment on Tobacco Value 2005

  32. Fertilization • Even though there is no yield response to P application on high P soils there may an early growth response • Especially under cool, wet conditions immediately following transplanting • Ability of a small root system to “find” phosphorus if none is applied in fertilizer

  33. Effect of Fertilizer Treatment on Flowering 2005 UCPRS

  34. Fertilization • Same early growth response from 20 lbs of P from 6-3-18 or 5 lbs of P in the transplant water • Allows for a significant reduction in P application without affecting early season growth • Allows for alternative K sources • Allows for 100% of N to be supplied from a N only product

  35. Nitrogen Study • Two Locations Kinston and Oxford • Three Sources Ammonium Nitrate Calcium Nitrate 30% UAN • Rates 0, 20, 40, 60, 80 (lb/A) - 2004 100, 120 (lb/A) – added in 2005

  36. Effect of N Rate on Tobacco Yield and Value at LCPRS * * 2004

  37. Effect of N Rate on Tobacco Yield and Value at LCPRS * * 2005

  38. Fertilization • Avoid K and N sources that contain more than 20-30 lbs of Cl per acre • State Law limits Cl levels in “tobacco grade” fertilizers • Only small amounts of KCl are acceptable • K Mag • Sulfate of Potash

  39. Fertilizer Selection • Choose ratio based on soil test P. • 0 Lb/A: 1-0-3 (8-0-24), 0-0-1 (0-0-30, 0-0-22) • 1-40 Lb/A: 1-1-3 (6-6-18, 8-8-24) • 41-80 Lb/A: 1-2-3 (4-8-12, 6-12-18) • 81+ Lb/A: 1-3-3 (3-9-9, 6-18-18) • Apply at the rate to supply all of the P recommended and no more than 40 Lb N/A.

  40. Fertilizer Selection • Additional N from a sidedresser • Use N/K sidedresser if additional K is needed. 15-0-14, 13.5-0-14

  41. Nitrogen Applications to Partially Drowned Tobacco Peedin, 2 Loc., 1995

  42. Effect of Fertilizer Addition to Partially Drowned Tobacco Peedin, 2 Loc., 1995

  43. Organic Nitrogen • Undesirable for tobacco • Organic N not adsorbed by roots. Must undergo mineralization prior to uptake. • Mineralization rate is unpredictable. • Makes rate determination difficult. • Usually too slow, and contributes to late-season N uptake. Delays ripening.

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