Use of Strip-Tillage Systems for Dark-Fired Tobacco Production in Western Kentucky USA

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1 CORESTA Agro-Phyto Meeting November 6-10 Santiago, Chile - AP14 Use of Strip-Tillage Systems for Dark-Fired Tobacco Production in Western Kentucky USA A. Bailey, B. Toon, C. Harper, and R. Pearce University of Kentucky

2 Conservation Tillage in Kentucky Conservation tillage = any method of soil cultivation that leaves the previous crop s residue on the field before and after planting the next crop. Primary production method in major agronomic crops in Kentucky: Crop Total hectarage in KY No-Till hectarage in KY Soybean 567,000 ha 510,000 ha (90%) Corn 542,000 ha 434,000 ha (80%) Wheat 158,000 ha 110,000 ha (70%) *Source: KY data from USDA, National Agricultural Statistics Service.

3 Benefits of Conservation Tillage Systems Soil conservation: Reduces soil erosion by 75 to 100% Water conservation: Increases water availability by 20 to 25% Reduces runoff and soil evaporation, increases water infiltration Reduces time required for land preparation Reduces energy requirements by 50 to 75% Increases use of marginal land for crop production Increases timeliness of field operations *Source: AGR-101, No-Till Soybeans

4 Conservation Tillage Systems for Tobacco Conservation tillage has not been widely adopted for tobacco Reasons: Primary tillage and cultivation have been a major component of tobacco weed control programs Lack of herbicides registered for tobacco Tobacco growers perception of need for nearperfect plant stands that may be more likely with conventional tillage systems.

5 Primary Tillage and Tobacco Subsoiling Moldboard plowing If following perennial grass Chisel plowing Multiple disking Soil finishing As much as 6 hours per hectare in land preparation and cultivation

6 Cultivation and Tobacco Typically cultivated at least twice in the first 5 to 6 weeks. Reasoning: Supplement weed control Prevent soil crusting Add soil to base of plant to increase standability and reduce sucker growth from base of plant Risks: Root and leaf damage from excessive cultivation Transmission of diseases like Phytophthora and TMV.

7 Grower Concerns with No-Till Poor stands? More stand loss with no-till but losses minimal (<3%) No or minimal effect on yield/ha Premature flowering? Effect documented with no-till dark tobacco in established fescue sod residue Presumably due to root competition with dense root system of grass Minimal effect (1%), no effect on yield/ha

8 Conservation Tillage Tobacco in KY 29,000 hectares burley tobacco, 2-3% no-till, 7-8% strip till 5,500 hectares dark tobacco, <1% no-till, >15% strip till No-Till No tillage preparation prior to transplanting Strip-Till Minimal tillage preparation in strips where tobacco will be transplanted

9 No-Till - Transplanter Modification No-till Coulter Cuts residue Provides narrow tilled zone Subsoil shank Provides loose soil under root ball Pulls unit into soil Press wheels Close and firm soil around roots *Source: R. Pearce

10 Why Strip-Till instead of No-Till? Strip-till considered a hybrid of conventional tillage and no-tillage: 30 to 40 cm tilled strip for transplanting, row middles no-till No transplanter modifications needed for strip-till Dark tobacco yields appear to be comparable in conventional and strip-tillage systems Yield lower in some instances with no-till Plant stand with strip-till comparable to conventional tillage (typically better stand than with no-till)

11 Strip-Tillage Systems for Tobacco Good conservation of soil and water Less soil erosion than with conventional, but not as good as no-till May open up ground previously unsuitable for tobacco production Soil tilth improved over 4 to 5 year period Fuel savings in land preparation 0 tillage passes with no-till As few as 2 tillage passes with strip-till 5 to 6 tillage passes sometimes used for conventional tillage Weed control may be the biggest concern in strip-till and no-till Particularly glyphosate-resistant horseweed populations in west KY/TN Potentially cleaner tobacco at harvest Strip-till yields comparable to conventional tillage with normal rainfall, may yield better in a dry year?

12 Strip-Tillage Systems for Tobacco Disadvantages: Expensive initial equipment costs Still some potential for erosion in crop row Additional herbicide costs Burndown application required prior to land preparation Glyphosate (30 days prior to transplanting) Paraquat (may require multiple applications) May need to increase rates of standard herbicides More potential for weed problems? Labor for weeding? Nitrogen sources/pesticides that require incorporation?

13 Strip-Till Tobacco Forming Strips Strip-till unit Used to establish strips 4-row implement: approx. $16,500

14 Strip-Till Tobacco Strip Finishing Multivator Used to freshen strips prior to transplanting 4-row implement: approx. $11,000

15 Strip-Till Tobacco General Production Guidelines Form strips in the fall if possible Can rework in spring if needed and use multivator prior to transplanting Soybean/corn residue best, long-term fallow (CRP) or sod least ideal Need at least 60% residue cover in row middles to see full benefit Burn down with glyphosate in fall, can reapply glyphosate in spring up to 30 days prior to transplanting Field must be clean when tobacco is transplanted Can add paraquat to tobacco herbicides to kill any green vegetation Use full rates of best herbicides Sulfentrazone: 0.35 to 0.42 kg ai/ha Clomazone: 0.84 to 1.12 kg ai/ha

16 Strip-Till Tobacco Fertilizer Application Fertilizer sources: P and K: any standard source can work, soil test to see if needed If band applied, can reduce recommended P and K rate by 1/3. Nitrogen: do not reduce recommended rate even if banded Ammonium nitrate, UAN, or ESN are good N sources Urea not preferred unless treated with urease inhibitor

17 Problems with tobacco after harvesting wheat Soil microbes breaking down wheat residue will compete for nitrogen applied for tobacco

18 Dark-Fired Variety Performance in Different Tillage Systems 2010 Dale Seay Farm Christian Co., KY Variety Conventional Tillage Strip Tillage Total Yield (kg/ha) No Tillage Variety Average NL Madole LC PD 7312 LC PD 7318 LC PD 7305 LC KT D4 LC KT D6 LC KT D8 LC DT 538 LC D Tillage Average

19 Dark Tobacco Yield Comparisons of Conventional Tillage vs. Strip-Tillage On-Farm Trials Location Variety Year Carlisle Co., KY Narrowleaf Madole LC Conventional Tillage Yield (kg/ha) Strip-Tillage Yield (kg/ha) McLean Co., KY KT D8LC McLean Co., KY DT 538LC Caldwell Co., KY Narrowleaf Madole LC Average Yield

20 Yield (kg/ha) Yield Comparison in Dark-Fired Tobacco Bobby Toon Farm Carlisle Co., KY 96 kg/ha yield increase for strip-tillage $5.64/kg dark-fired price $541.44/ha increased revenue LSD 0.05 = (total) Conventional Tillage Lug Second Leaf Total Yield (kg/ha): Strip Tillage

21 Conventional Tillage Herbicide Costs/Ha Bobby Toon Farm Carlisle Co., KY Sulfentrazone 0.28 kg ai/ha Pendimethalin 0.8 kg ai/ha $60.54/ha $15.96/ha $76.50/ha

22 Strip-Till Herbicide Costs/Ha Bobby Toon Farm Carlisle Co., KY Flumioxazin 0.07 kg ai/ha Glyphosate 1.05 kg ai/ha Paraquat 0.56 kg ai/ha Sulfentrazone 0.35 kg ai/ha Pendimethalin 1.06 kg ai/ha $22.86/ha $6.67/ha $14.97/ha $75.66/ha $21.28/ha $118.58/ha

23 Conventional Tillage Land Prep Costs/Ha Bobby Toon Farm Carlisle Co., KY 2 pass disk $32.12/pass 1 pass chisel $37.07/pass 1 pass standard herbicide $17.30/pass 3 pass soil $32.12/pass 3 pass $25.95/pass $64.25/ha $37.07/ha $17.30/ha $96.37/ha $77.84/ha Total Conventional Till Machinery Cost = $292.83/ha *Source: 2011 Univ. of KY Custom Machinery Rates

24 Strip-Till Land Prep Costs/Ha Bobby Toon Farm Carlisle Co., KY 2 pass spray (burndown + $17.30/pass $34.59/ha 1 pass $48.18/pass $48.18/ha 1 pass soil finish $32.12/pass $32.12/ha Total strip-till machinery costs = $114.89/ha *Source: 2011 Univ. of KY Custom Machinery Rates

25 Strip-Till Equipment Expense Total equipment cost $27,500 $3,928.57/year depreciation for 7 years $196.43/ha for 20 hectare grower

26 Economic Assessment of Tillage Systems Bobby Toon Farm Carlisle Co., KY Costs Strip-Tillage Conventional Tillage Land Preparation Costs ($/ha) $ $ Herbicide Costs ($/ha) $ $76.50 New Equipment Costs ($/ha) $ Hand Weeding ($/ha) $47.40 (5 $9.48/hr) Tillage System Costs ($/ha) $ $ Gross Revenue difference ($/ha) +$ Additional Cost for strip tillage ($/ha) -$ Revenue advantage for strip till ($/ha) +$433.47/ha 0

27 Summary Although not as environmentally sustainable as no-till, strip-till is more sustainable than conventional tillage. Land preparation costs reduced by 61% and herbicide costs increased by 55% with strip-till. Additional equipment expenses could be defrayed as used equipment becomes available. If yield advantages for strip-till are consistent, there appears to be an economic advantage to strip-tillage.

28 Special Thanks to U.S. Smokeless Tobacco Co. for support of this work.