1. From Conventional to Organic: Weed Management Principles for the Transition Years Fabián Menalled 719 Leon Johnson Hall Montana State University menalled@montana.edu 406-994-4783

2. A Disclaimer This is not going to be a “traditional” weed extension presentation Your best weed management tool is located between your ears www.forages.oregonsate.edu

3. Today, we’ll talk more about principles than specific practices

4. Outline for Today ’ s Presentation  Transitioning to organic What to expect  Some basic concepts What is a weed? Why do we have weeds?  Integrated Weed Management (IWM) in organic systems

5. From Conventional to Organic What to Expect Yield Time Stop Synthetic Herbicide & Fertilizer Inputs Weeds

6. What ’ s the Impact of Transitioning from Conventional to Organic on Weed Communities?

7. Study Sites Big Sandy Moore

8. Methods Study Area: Moore & Big Sandy, MT Plots = 3 conventional (445.3 m 2 ) and 3 organic (222.65 m 2 ) Measurements: Number of species Individuals/species Number of species/plot 0.1 m 2 10 m 2 1 m 2 Whole Plot

9. Shared Canada thistle Crazyweed Kochia Prickly lettuce Redroot pigweed Russian thistle Wild buckwheat Wild oat Conventional A. septentrionalis Perennial ryegrass Organic Alfalfa Barley Pea Winter vetch Common chicory Common lambsquarters Cowcockle Cheatgrass False flax Field pennycress Weed Species - Big Sandy, MT Canada goldenrod Green foxtail Cutleaf nightshade Tansy mustard Crossflower Milkweed Rush skeletonplant Common sunflower Tall tumblemustard Wild mustard Yellow starthistle

10. From Conventional to Organic What to Expect Abundance Diversity Species composition Spatial patterns in reduced input & organic systems Shift ??????

11. Why Assessing the Spatial Distribution of Weeds? Weeds in conventional systems are distributed as patches Dieleman et al., 1999; Faechner et al., 2002; Hughes, 1990; Mortensen et al., 1995; Rew and Cousens, 2001; Wiles et al., 1992 Precision agriculture Weed distribution in organic systems? Site specific agriculture

12. Spatial Patterns Percentage cover / spp. Weed species richness, diversity 1 m RANDOM Weed patch 100 m Big Sandy, MT 3 conventional fields 3 organic fields Stratified sampling

13. CON1 T2 ORG1 T2 Organic Patch Group of Patches Gap Patch Group of Patches No Gaps! Group of Groups of Patches Conventional

14. From Conventional to Organic What to Expect Abundance Diversity Species composition Spatial patterns in reduced input & organic systems Shift complexity

15. The sky is falling! X isn’t Weeds = Yields This relationship isn’t constant Yields = Profits

16. Weed Abundance & Yield Yield Weed abundance

17. When transitioning, don’t go “the whole enchilada” but take “baby steps”

18. Outline for Today ’ s Presentation Transitioning to organic What to expect  Some basic concepts What is a weed? Why do we have weeds?  Integrated Weed Management (IWM) in organic systems

19. Questions, so far?

20. Photos Source: WSSA web site. Ian Heap What is a Weed?

21. A plant that is growing where it is not wanted Roberts et al. 1982. Weed Control Handbook

22. Any Problem With this Definition?

23. Source: C. Mohler Understand the source of your problems

24. LightWaterNutrientsSpace Why Do We Have Weeds?

25. BECAUSE WE CREATE THE ENVIROMENTS WHERE WEEDS THRIVE!

26. Weed Management is Achieved Through USDA Online Photography “large hammer”

27. Soil erosion Surface and ground water contamination Resistance Good in the short term, but don’t work on the long term We still have weeds! Doesn’t treat the source of the problem but its consequences Limitations of Large Hammers

28. SeedlingsAdults New SeedsSeedbank Weeds Are Plants! Seedling Recruitment Seedling Survival Seed Mortality Fecundity Seedbank Survivorship

29. Alternative Weed Management  Replace a “ few large hammers ” with “ many little hammers ” (herbicides, tillage, crop rotation, pathogens, insects, cover crops, etc)  Alone, each factor may have a small effect. Together, these factors may provide sufficient control Liebman and Gallandt 1997 Integrated Weed Management

30. Outline for Today ’ s Presentation Transitioning to organic What to expect Some basic concepts What is a weed? Why do we have weeds?  Integrated Weed Management (IWM) in organic systems

31. Questions, so far?

32. Weed Management Cultivation

33. Weed Management Cultivation Prevention

34. Standard weed management conducted at the field level 270% expansion over 6 years Standard weed management + weed shed prevention 24% expansion over 6 years After H. Beckie, Agri-Food Canada @ Saskatoon 19972002 19972002 Do Not Spread Weed Seeds!

35. Weed Management Cultivation Seeding density Row spacing Prevention

36. Row Spacing and Seeding Rate 20 site-years in Oklahoma ---- 60 lb/A ---- ---- 120 lb/A ---- 0 5 10 15 20 25 30 35 Wheat yield (Bu/A) 9393 Row spacing (inches) Weed Free Cheat -- 60 lb/A -- -- 120 lb/A -- Epplin et al. 1996

37. Weed Management Cultivation Crop variety Seeding density Row spacing Prevention

38. Crop Variety After Jones & Murphy, 2006 Weed tolerance Weedy Weed Free Harrow tolerance Weed suppression

39. Crop Variety After Jones & Murphy, 2006 OrganicConventionalPercentage Madsen8311075 Eltan9291101 Rod9811288 Stephens8411275 Finch9812578 Mean9111083 Yield (bu/a) – Pullman WA

40. Crop Variety Cultivars vary in their competitive ability: Height Early season growth Tillering capacity Leaf area Some varieties are better adapted to weed competition than repeated harrowing and vice versa Mason and Spaner, 2006 & Jones and Murphy, 2006

41. Weed Management Cultivation Crop rotation Crop variety Seeding density Row spacing Prevention

42. fallowwheatfallowwheatfallowwheat Grassy Weeds

43. Crop Rotation and Cheatgrass Density Downy brome density (no. m -2 ) (After Blackshaw 1994)

44. Weed Management Cultivation Crop rotation Crop variety Time of emergence Seeding density Row spacing Resource management Time of control Weed Management

45. Relative Time of Emergence

46. Weed Management Cultivation Crop rotation Crop variety Time of emergence Seeding density Row spacing Resource management Time of control Integrated Weed Management

47. You Are Not Alone….

48. http://eorganic.info

51. In Summary …

52. The sky is falling! X isn’t Principle # 1: Don’t hate weeds, manage them

53. Principle # 2: Take “Baby Steps”

54. Source: C. Mohler Principle # 3: Understand the source of your problems

55. Weed Management Herbicides Crop rotation Crop variety Time of emergence Seeding density Row spacing Resource management Time of control Principle # 4: Use All Your Tools!

56. Principle # 5: ASK!

57. Principle # 6: Your best weed management tool is located between your ears! www.forages.oregonsate.edu

58. Be Smart!

59. Questions?