Organic weed management: proven and new approaches

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I shared this presentation at the MN Organic Conference on 1/11/2013

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Organic weed management: proven and new approaches

  1. 1. Organic weed management in field crops Proven and new approaches Dr. Joel Gruver Western Illinois University j-gruver@wiu.edu
  2. 2. PRECISION Currently only available upon request Will soon be downloadable from our websitehttp://www.wiu.edu/cbt/agriculture/farms/organic/
  3. 3. High tech precision vs. attention to detail
  4. 4. In 2012, I witnessed a new level of attention to detail
  5. 5. Why is there rapeseed on the edge of this bean field? Prior to working with Gary, I was under the impression that cultivation had limited ability to control in-row weeds and wondered if in-row cover crops might be of value
  6. 6. Steel in the Field shows how todays implements andtechniques can control weeds while reducing—or eliminating—herbicides.In practical language, Steel in the Field presents whatfarmers and researchers have learned in the last 20 years about cutting weed-control costs through improved cultivation tools, cover crops and new cropping rotations.
  7. 7. STEEL in the FIELDRow crop farmer profilesDryland farmer profiles
  8. 8. Weed control, however, starts in October.“The last cultivation in fall is our first weed management for spring,” Jacobson says. He uses 4- inch beavertail shovels(pointed at the bottom, wide at the top) on his chisel plow. The shovels leave soil roughly ridged with some incorporation of residue. The pass exposes roots of fall growing weeds such as quackgrass and field bindweed towinter’s wrath. He makes a second fall pass if weeds begin to regrow, or if quackgrass is a problem.
  9. 9. To stimulate weed growth, he harrows in late April as soon as soil dries out.His Herman stiff-tine harrow has round tines about 5/16ths of an inch in diameter..He controls the subsequent weed flush with a fieldcultivator outfitted with 9-inch sweeps. He makes asecond pass if weed pressure is heavy and if he can delay planting.
  10. 10. Terry uses a Seed-Right hoe drill
  11. 11. Crop Rotation on Organic Farms: A Planning Manual provides anin-depth review of the applications of crop rotation-including improving soil quality and health,and managing pests, diseases, and weeds. Consulting with expertorganic farmers, the authors share rotation strategies that can be applied under various field conditions and with a wide range of crops. Crop Rotation on Organic Farms is most applicable to farms in the Northeastern United States andEastern Canada but is worth a look
  12. 12. Conservation Augmentation3 broad goals of Activation ecological management Suppression
  13. 13. A nice flush of weeds ready for terminationWhat can we do to maximize this flush? Not all tillage operations have the same effect
  14. 14. Terminating spring planted oats with a soil finisher ~ 3 weeks before planting cornGOAL = biological activation and weed suppression
  15. 15. Planting into poorly digested red clover residues Corn seed was planted into moisture but ~ 25% of one hybrid and > 50% of another was lost to seed rot and insect feedingWe had near perfect stands in every other field
  16. 16. Are you familiar with the fence post principle? Zone of maximum biological activity and rapid residue decay Deeper burial does not optimize decay but sends weed seeds into deep dormancy and brings deeply dormant weed seeds to the surface where they germinate slowly
  17. 17. Who is sleeping in your soils?
  18. 18. Do any of you have experience with flame weeding? Terminating weeds without awakening sleeping seeds Dennis Leutke in MN and Larry Shrock in MO are experts
  19. 19. Cropping system strategies vs. Direct control strategies
  20. 20. Effective strategies disrupt weed life cycles
  21. 21. Cropping system strategies Crop rotation Tillage rotation Cover cropping Crop management Fertility management Manure management Field/equipment/seed sanitation
  22. 22. Optimizing crop growth to maximize crop competitiveness-Select a well adapted variety (maximumleafiness and rate of canopy closure)-Delay field work (soil must be warm enough forrapid crop emergence)-Prepare a good seed bed (start out clean)-Reduce row spacing and increase populations-Row fertilizer?
  23. 23. Preventive management• Flush soil seed bank with fallow periods• Walk crops• Employ alternative equipment for mowing, pulling weeds• Weedy crops -> forage or cover crops
  24. 24. Hopefully it doesn’t really take 15 years for preventative management to pay
  25. 25. Well established fall planted small grains are very competitive against weeds
  26. 26. Do you see a cover crop?
  27. 27. Do you see a cover crop? Frost seeded clover the most tried and true cover cropping system in the Midwest region
  28. 28. Frost seeding options Sweet cloverMustard
  29. 29. Klaas and Mary Martens, organic innovators in Central NY State, are reporting excellent results with frost-seeded confectionary mustard ahead of dry beans
  30. 30. Results would probably be opposite during a normal or wet year Preceded by radish :-<
  31. 31. Where are the soybeans?? Traditional organic weed management often comes up short during wet years A strong stand of cereal rye was incorporated~ 2 weeks before these soybeans were planted
  32. 32. Pioneering work by Jeff Moyer at the Rodale Institute has sparkedconsiderable interest in organic no-till across the country
  33. 33. Innovative farmers Innovation all have built lots of across the USinteresting looking rollers
  34. 34. Some times its best to make do with what you already have Cultimulcher Front mounted Rodale roller
  35. 35. October 2008 Cereal rye drilled at 60 lbs/a in late AugustOur experience is that a strong stand of rye is much more important than roller design
  36. 36. Early June 2009 1 week later
  37. 37. ~2 weeks after planting
  38. 38. JulyAugust late September
  39. 39. Early November 2009No-till, bio-strip-till and conventional till plot averages ranged from 51.6 to 58.6 bu/ac No significant differences between systems
  40. 40. We planned a ridge-till vs. no-till comparison for 2010
  41. 41. May 2010
  42. 42. July 2010 We drilled into standing rye without rolling on 6/7 because of a very narrow window between rains.We ended up knocking down the ridges and were not able to plant these plots until 7/4 due to excessive wetness
  43. 43. November 2010 Significant foxtail pressure but almost no broadleaf weedsPlot yields ranged from 42-52 bu/ac
  44. 44. June 2011
  45. 45. August 2011
  46. 46. November 2011The NT bean plots yielded~10 bu more than the best tillage system plots
  47. 47. April 2012
  48. 48. Planting into 5-6’ tall rye on May 11
  49. 49. Double drilled with 4” offset
  50. 50. June 2012
  51. 51. Our 2012 NT bean yields ranged from ~ 30 to ~ 60 bu/a
  52. 52. 60-70bu/a
  53. 53. In July 2012, we undercut several fields of small grain stubbleusing a Hinniker no-till cultivator and a tractor with RTK guidance
  54. 54. Cover crop cocktailFallow strip no-till drilled after undercutting
  55. 55. Triple S mixSunflowers, Soybeans & Sunn hemp
  56. 56. We started growing sunflowers in 2010 when >300%of normal precip in May, June and July kept us out of the fields planned for corn
  57. 57. July 17 planting
  58. 58. We could hardly believe it but this field of sunflowers planted on 7/29 actually matured.Sunflowers are now a weed clean-up crop in our rotations
  59. 59. Steering (Autosteer) Vehicle control Steering (assisted steering) PrecisionMechanization Steering (passive) Implement Steering control (active) Planter row unit control
  60. 60. Strip intercropping 230 bu/ac in 2010 Jacob
  61. 61. Exciting developments are happening but the foundation of successful weed management in organic row crops will continue to be healthy crops and healthy soil

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