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 NutrientPounds/Acre Nitrogen70 Phosphorus12 Potassium80 Calcium55 Magnesium22 Sulfur18 McCants and Woltz

10. Nutrient Removal by a 2000 Pound Tobacco Crop NutrientPounds/Acre Boron0.07 Manganese0.7 IronTrace ZincTrace Copper0.04 MolybdenumTrace McCants and Woltz

12. 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.

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

14. 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.

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

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

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

18. Nitrogen The Most Important Nutrient Affecting Yield and Quality

19. 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.

20. 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.

21. Effect of Nitrogen Rate on Quality Quality Factor N Rate123 -------------Percent--------------- Low30700 Rec.25732 Excess196417

22. Suggested Base Nitrogen Rates Based on Topsoil Depth

23. 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.

25. Nitrate Reduction and Starch Accumulation- Ideal Conditions

26. Nitrate Reduction and Starch Accumulation- Delayed N Uptake

27. Nitrate Reduction and Starch Accumulation- Restricted N Uptake

28. 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.

29. 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.

30. 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

31. 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

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

33. Effect of Fertilizer Treatment on Tobacco Value 2005

34. 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

36. Effect of Fertilizer Treatment on Flowering 2005 UCPRS

37. 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

38. 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

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

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

41. 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

42. 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.

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

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

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

46. 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.