Tobacco Production Update Bob Pearce, Gary Palmer, Andy Bailey Extension Tobacco Specialists Kenny Seebold Extension Plant Pathologist

Topics Nitrogen sources for tobacco Revised nitrogen rates for tobacco Sucker control options –No MH options Variety update Disease update

Nitrogen Fertilizer Issues Economics –Leaf prices down –N fertilizer prices up Price tied to natural gas Transportation costs up Nitrosamine concerns –Tobacco companies want less N applied Quality concerns –Too little: thin body, poor yield –Too much: delayed maturity, fat stems

Ammonium Nitrate Issues Most common N source for tobacco growers Homeland security concerns –Can be used to make explosives –Easy availability Some manufacturing plants have closed –Tighter supplies –Higher costs Sales regulations –Permits needed to purchase large quantity? –Some dealers reluctant to stock?

Price Per Unit of Nitrogen for Selected Fertilizer Materials

Alternative N Sources Anhydrous ammonia (82% N) –Lowest cost per unit of N –Limited availability –Special equipment needed Stored as liquid under pressure Special injectors needed Used in illegal meth production –Feasible only if equipment already available –Placement concerns Delayed uptake Phyto-toxicity if close to plants

Alternative N Sources Anhydrous ammonia (82% N) –Reaction in soil NH 3 + 2O 2 → H + + NO 3 - +H 2 O Same lime requirement as AN –Suggestions for use Inject 6 to 8 inches deep 7 to 10 days before setting

Alternative N Sources Ammonium sulfate (21% N) –Specialty fertilizer Use on acid loving crops Use on high pH soils –Relatively high cost per unit N –Limited availability –Soil reaction (NH 4 ) 2 SO 4 + 4O 2 → 4H + +2NO SO H 2 O 3X lime requirement of AN –Not feasible for large scale use on tobacco

Alternative N Sources Urea (46% N) –Intermediate cost –Handling similar to ammonium nitrate Can impregnate some chemicals Same lime requirement as AN –Converted to nitrate in the soil Subject to loss if surface applied –Apply to dry soil –Incorporate or water in Delayed uptake (Don’t use for sidedress) –Feasible alternative if managed properly

Alternative N Sources Non Pressure Solutions (28 – 32% N) –Intermediate cost –Mixture of urea, ammonium nitrate, and water –Relatively easy to transport, store, and apply Most nurse tanks Many types of sprayers –Corrosive to equipment –Should be incorporated –Can be used a a carrier for spray applications –Limited availability –Feasible for tobacco production

Alternative N Sources Calcium – Ammonium Nitrate (27% N) –Ammonium nitrate mixed with lime 78% ammonium nitrate –Theoretically similar to ammonium nitrate Can impregnate some chemicals ? –Relatively high cost? –Availability? –Limited practical experience

Alternative N Sources Sodium Nitrate (16% N) Calcium Nitrate (15.5% N) Sodium-Potassium Nitrate (15% N) –Immediate uptake (good for sidedress) –Good for low pH soils –Erratic availability –High cost –Low analysis – high transport cost

Conversion to Nitrate in soil % of Fertilizer as NO 3 -N N SourceWeeks After Application 036 Ammonium Nitrate Anhydrous Ammonia02065 Urea05075 UAN Solution Nitrate Sources100

Effects of Ammonium Nitrate Application on Soil pH Anhydrous Ammonia, Urea, UAN solutions : similar

Effect of Liming an Acid Soil Prior to Use of Urea and Sodium Nitrate Sources of Nitrogen Both N sources applied at 225 lb N/A pre-plant. Soil pH (water) measured at midseason of each year. Soil pH before liming was 5.4.

Effect of Liming an Acid Soil Prior to Use of Urea and Sodium Nitrate Sources of Nitrogen Both N sources applied at 225 lb N/A pre-plant.

Nitrogen Source Study Harrison Co. – Keith Smith Farm 100 units AN Broadcast Sidedressed with 170 units each, AN = Ammonium Nitrate, U= Urea, CN = Calcium Nitrate, SN = Sodium Nitrate

Conventional Fertility Trial Monroe Co. – Al Pedigo Farm Number = lbs of product, AN = Ammonium Nitrate, CN = Calcium Nitrate, SN = Sodium Nitrate, U= Urea Broadcast Sidedress

No-till Fertility Trial Monroe Co. – Al Pedigo Farm Number = lbs of product, AN = Ammonium Nitrate, CN = Calcium Nitrate, SN = Sodium Nitrate, U= Urea Broadcast Sidedress

Effects of Sidedressing Different Sources of Nitrogen on Burley Yield Elliot Co. – Tracy D. Kitchen Farm 450 Ammonium Nitrate Broadcast followed by 100 lb/a of Nitrogen Sidedressed. Am = Ammonium, Ca = Calcium & Na = Sodium. There were no significant differences.

Effect of Nitrogen Source on Burley Yield Marshall Co. – Glen Thompson Farm units Urea Broadcast Sidedressed with 100 units each at sidedressing, Ca = Calcium and Na = Sodium

Revised Nitrogen Rates AGR-1 will have a new table for N on tobacco –Based on crop history (same as old) –No additional N for continuous tobacco –Soil drainage formally considered –“Typical” recommendation 50 lbs. N/A less –Rate lower if sidedressing is practiced Economically sound recommendations Reduce incidence of over-application

Revised Nitrogen Recommendations for Burley and Dark Tobacco. Well Drained Soil Moderately Well Drained Soil Lb N/A Low N levels: following tobacco or row crops Medium N levels: first-year tobacco following a grass or grass-legume sod High N levels: first-year tobacco following legume sod or legume cover crop

Effects of Nitrogen Rates on Burley Tobacco at Spindletop Farm (Maury Silt Loam) –MacKown, Sutton and Crafts-Brander – 1994

Nrate across location years and method

Effect of N rate and method of application on burley tobacco yield. If 1/3 or more is sidedressed reduce total amount of N by 15 to 25 lbs./A

Summary Encourage growers to compare costs and consider alternative N sources Revised N rates –Rates lowered by about 50 lbs./A –Will not significantly lower yield –Improved quality –Promotes desired chemical properties Reduce rate if sidedressing is practiced