Response of Tobacco to Soils and Soil Management

1. Response of Tobacco to Soils and Soil Management Dr. Bob Pearce Extension Tobacco Specialist Agent Training June 18th, 2009

2. Soil Provides • Support • Root and stems to prevent lodging • Nutrients • Release of naturally occurring • Store and release fertilizer • Water • Air • For root respiration

3. Important Soil Properties • Physical • Soil Texture • Soil Structure • Drainage • Depth to Rock or other limiting layer • Chemical • Soil pH • Fertility levels

4. Determining Soil Properties • Drainage • Tobacco prefers well drained soils • Red/Brown color, avoid grays • Soil survey maps • Web Soil Survey • Fertility and pH • Soil test

5. Field Site Selection • Soil properties • Drainage • Fertility • pH • Crop history • Length of rotation /disease potential • Chemical carryover from previous crop • Proximity to water for irrigation • Proximity to curing structure

6. What is “Conventional” Tillage for Tobacco???

7. Conventional tillage • Moldboard plow in late winter/early spring • Smooth with a heavy drag • Secondary tillage • 2 to 6 diskings or • 1 to 2 passes with a roto-tiller • 2 to 4 post transplant cultivations

8. Why do we practice tillage??

9. Why do we practice tillage? • Weed control • Alleviate compaction • Improve aeration • Incorporate organic matter • Incorporate chemicals and fertilizer • Improve transplanter operation

10. Negative Aspects of Tillage • Reduces organic matter in soil • Weakens soil structure • Reduced nutrient and water holding • Physically destroys soil structure • Increases soil loss from erosion • Can create compaction • Working ground that is too wet • Increased fuel usage

11. Compaction created with a disk

12. Idealized Soil Air 25% Soil Minerals (Silt loam) 47% Water 25% Organic Matter 3%

13. Air 5% Water 20% Soil Minerals (Silt loam) 72% Compacted Soil Organic Matter 3% Macropores are compressed soil oxygen decreased dramatically Effects Poor Drainage Slow Root Growth

14. Proctor Compaction Curve Optimum M.C.=14.3% for a silt loam PotentialCompaction 8 10 12 14 16 18 20 22 Soil Moisture Content (%)

15. Plow Compacted Layer

16. Disk

17. Compaction caused by tillage 4 – 8” 0.5 – 2” Inaccessible water and nutrients

18. Soil Compaction?

21. In-row subsoiling for tobacco Yield (lbs./A) Murdock et al. 1986

22. Effect of Disking and In-row Subsoiling Yield (lbs./A) Murdock et al. 1986

23. Summary of In-row subsoiling • Increased yields where compaction was documented • Increased plant survival and early growth • Needs to be done in “dry” soil • In wet soil creates an air pocket • Simple, inexpensive process that can improve root environment at transplanting.

24. Management of tillage induced compaction • Avoid working wet ground • Rotation to deep rooted sod crops • Fall tillage (subsoiling) • Characterize compacted layer (depth and thickness) • Till to bottom of compacted layer • Dry soil tends to shatter better • In-row subsoiling prior to transplanting • Just to depth of compaction

25. In-row subsoiler on transplanter

26. No-till Tobacco Production • Soil Conservation • Moisture Conservation • Reduced Field Preparation • Allows timely field operations • Cleaner cured leaf

27. Challenges of No-till Tobacco • Transplant Establishment • Weed Control • Cover Crop Management • Variety Selection • Fertilization

28. Transplanter Modification • No-till Colter • 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

29. Transplanter Modification

30. Challenges of No-till Tobacco • Transplant Establishment • Weed Control • Cover Crop Management • Variety Selection • Fertilization

32. Spartan + Command Check

33. Suggested weed control program for no-till tobacco • Spartan 4F - required • 10 to 14 days before plant • 10 to 12 oz./A • Command 3 ME – recommended • Tank mix with Spartan • Post with in 7 days of transplanting (preferred) • 2.0 to 2.67 pints/A • Prowl 3.3 EC – optional • Tank mix with Spartan • 2 to 3 pints/A

34. Post transplant weed control • Mechanical means • Mower, weedeater • Cultivation • Poast – Grass Control • 1.5 pint/A • Shielded/directed Sprays • Non-selective -- label issues • New chemistry ???

35. Shielded spraying on no till tobacco

36. Challenges of No-till Tobacco • Transplant Establishment • Weed Control • Cover Crop Management • Variety Selection • Fertilization

37. 30 days 15 days 1 day

38. Strip till vs no-till Kermit and Ray-Lewis Coffey Wayne County -2001 • Advantages • Use conventional setter • Incorporate pesticides and fertilizer • Disadvantages • Additional field passes • Preferential water flow and erosion in the strip

39. Learn as much as possible Extension sources Magazine articles Other growers Start slow, and learn fast !! Greater attention to detail Plan ahead Select sites carefully Past crop history Weed pressure Soil type Potential to improve production Not suited to all soils Heavy clay Wet natured Higher management Not as forgiving Still developing Conservation Tillage Tobacco is an Emerging Practice