Systems strategies for organic weed management

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This is a slightly edited version of a presentation that I shared at the Organic Farming Conference in La Crosse WI on Friday 2/24/2012

This is a slightly edited version of a presentation that I shared at the Organic Farming Conference in La Crosse WI on Friday 2/24/2012

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  • 1. Systems strategies for organic weed management Crop Joel Gruver (309) 298 1215WIU Agriculture J-gruver@wiu.edu
  • 2. Who is sleeping in your soils?
  • 3. Which weeds would emerge if you brought soil inside right now?
  • 4. The soil bud bank Besides seeds, other dormant meristems, propagules, may accumulate in the soil in large numbers: -bulbs -bulbils (aerial bulb; e.g. lillies) -buds on rhizomes (e.g. quackgrass) -corms (enlarged, rounded, underground stem) -tubers (e.g. jerusalem artichoke) -buds on rootstocks (e.g. common milkweed, hemp dogbane) Difference between bud and seed banks:-buds are clonally reproduced, and as such are of the same genotype successful in leaving buds in the soil -seeds buried in the soil are potentially new genotypes, potentially untested; exception: self-pollinated weed seed species
  • 5. Does an inform yourunderstanding weedof seed/bud managementdormancy decisions?
  • 6. Seed rain Are you managing Seedlings the whole cycle?Predation Active Seed- Dormant bank seedbank Senescence & Decay Death
  • 7. 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
  • 8. Conservation Activation Suppression3 broad goals of ecological Augmentation management
  • 9. Direct control strategies vs.Cropping system strategies
  • 10. ABCs of mechanical and cultural weed management Page 11 – Steel in the Field A. Give the crop the advantage. B. Keep weeds on the defensive. C. Accept weeds that don’t really matter.Excellent reference describingequipment for direct control of weeds
  • 11. Cropping system strategies Crop rotation Tillage rotation Cover cropping Fertility/manure management Field/equipment/seed sanitation Crop establishment and management
  • 12. Optimize crop establishment to maximize competitive advantage-Select well adapted varieties (maximumleafiness and rate of canopy closure)-Delay planting (soil must be warm enough forrapid crop emergence)-Prepare a good seed bed (start out clean)-Reduce row spacing and increase populations-Row fertilizer?
  • 13. Preventive management• Flush soil seed bank with fallow periods• Walk crops• Employ alternative equipment for mowing, pulling weeds• Weedy crops -> forage or cover crops
  • 14. Ridge-till is a great example of a time-tested“cropping system” strategy for reducing weed pressureWhy aren’t more organicfarmers using ridge-till? Direct control
  • 15. Long-term controlled traffic before GPS
  • 16. No pre-plant tillage intended for this experiment Ridge till and No-till soybean strips should require no pre-plant tillage this spring
  • 17. Terminating spring planted oats with a soil finisher ~ 3 weeks before planting corn GOAL = biological activation and suppression
  • 18. No one hammer is likely to provide acceptable weed control Effective Integration oforganic weed = many little hammersmanagement Direct control strategies are much more likely to provide acceptable weed control if cropping system strategies have reduced weed pressure
  • 19. Effective strategies consistently andpersistently disrupt weed life cycles
  • 20. Successful organicfarming takes a high level of skill and will!
  • 21. 15 interviews completed2 1 3 5 3
  • 22. 15 interviews completed (14 farmers, 1 consultant) organic Name Location years farming acres livestock beef, hogs, chickens, Earl Hafner Panora, IA ~35/12 1800 tilapia Paul Mugge Sutherland, IA 35/13 300 none Scott Shriver Jefferson, IA 17/13 1800 none Jack Erisman Pana, IL >40/22 ~2500 beef Ted Weydert Dekalb Cty, IL 36/12 285 none Marvin Manges Yale, IL 34/25 1000 beef Clay Nielsen Atkinson, IL 22/7 75 beef Jeff Glazik Paxton, IL 15/8 400 beef Mike Findley Caro, MI 40/15 2200 none Steve McKaskle Braggadoccio, MO 39/21 1700 none Larry Shrock Middleton, MO 38/17 650 beefDavid Munsterman Montrose, MO 25/14 560 beef Lynn Brakke Moorhead, MN 31/19 ~2200 beef Lee Thomas Clay Cty, MN 30/10 1160 sheep, chickens 8 farms > 1000 acres & 3 farms > 2000 acres
  • 23. Basic biographical and background info:Name:Educational background:Farm location:Years farming: Years farming organically:Organic crops and acreage:Conventional crop and acres if applicable:Livestock enterprises:Organic certifying agency:Standard crop rotation(s) for organic crops:Standard tillage practices for organic crops:Most challenging weeds in organic fields:
  • 24. Questions about direct weed control tactics:o What cultivation tools do you use on your farm? Pleasebriefly describe how you use each tool (crops, timing,adjustment, ground speed, mechanical or GPSguidance…) and your level of satisfaction.o Do you have any experience with flame weeding? If so,please explain.o Do you have experience with any “organic” herbicides?If so, please explain.o Is manual labor (e.g., walking beans) part of the weedmanagement on your farm? If so, please explain.
  • 25. Questions about cropping system strategies for reducing weedpressure:o What role does primary tillage play within your overall approachto organic weed management?o What role does crop rotation play within your overall approach toorganic weed management?o What role do cover crops play within your overall approach toorganic weed management?o Do you use any specific methods of depleting the soil seed bank(e.g., fallow, stale seed bedding…? If so, please describe.o Do you have any specific clean-up strategies following weedcontrol disasters?o Do you specifically select crop varieties/hybrids for competitiveadvantage over weeds?
  • 26. Additional questions:o How are your standard organic weed management practices affected byextended wet conditions? Have you developed any effective techniques forcontrolling weeds organically during wet conditions?o How different are your weed management practices from other organic grainfarmers you know?o Do you know any organic farmers who seem to be particularly skillful weedmanagers? If so, what do you think gives them the edge?o What are your sources of information about organic weed management? (e.g.,books, conferences, other farms, websites, and etc.)o Are you considering any new weed management strategies? If so, pleaseexplaino Are there any specific aspects of organic weed management that you thinkneed more research? If so, please describe?Do you have any additional comments to share about organic weedmanagement that might benefit other organic farmers?
  • 27. Are there otherquestions that weshould be asking?
  • 28. Nearly all farmers delay planting until theyhave killed one or more flushes of weeds What can we do to maximize this flush? Not all tillage operations have the same effect
  • 29. Establishing a good stand is key!!
  • 30. Nearly all of the farmers use rotary hoes30’ rotary hoe
  • 31. About half of the farmers use tine weeders
  • 32. Rotary hoes and flex-tine weeders are most effective when the soil has a crustSome crop damage is inevitable but care should be taken to avoid times when crop is most fragile
  • 33. More than half of the farmers regularly use a flame weederTerminating weeds without awakening sleeping seeds
  • 34. All use inter-row cultivation
  • 35. JD 730 Air-Disk drill on Jack Erisman’s farm in Pana, ILJack uses this rig to drill soybeans on 6" rows (~ 280,000/ac) while also dropping about 2 bushel of rye and some micronutrients
  • 36. Some of the farmers using rolling baskets and other alternative cultivation tools
  • 37. 2 of the farmers use mechanical guidance and 3 use GPS guidance toincrease accuracy and reduce operator stress during cultivation
  • 38. Scott Shriver (Jefferson, IA)We have 4 tractors that can run in the crop and at timesall four are in use. Two of these are set up with RTKGuidance. We plant with the Guidance which makes ourrows more straight, which in turn makes the cultivatingeasier and allows us to set equipment tighter. Cultivatingwith the guidance is not completely automatic, butallows us to run faster and look behind more withoutdoing as much damage to the crop. Another thing Ihighly recommend is a hydraulic 3rd link on your tractor.This makes changing cultivator depth, rotary hoe andtined weeder pressure adjustments much easier, thusthey can be done more frequently and on the go.
  • 39. Mike Findley (Caro, MI)He has 2 Orthman single sweep cultivators, which had16” sweeps before he used RTK guidance on his tractor.He is on 22” row crop spacing and with GPS guidancecan cultivate as fast as 5 mph using 18” sweeps leavingonly 2” on either side of the crop to get weeds close tothe crop. He feels that having a 16 row mountedplanter (on 3 point hitch) also helps keep the planterfrom moving off a straight line especially on rollingground, which helps make cultivating even moresuccessful. A 60’ wide tine-weeder is used about 4 daysafter planting to control small weeds. He also made adouble rotary hoe a couple years ago that is used forweed control.
  • 40. Lynn Brakke (Moorhead, MN)He plants on 22” rows and can cultivate within 1 ½” oneach side of the crop row using RTK guidance andmechanical guidance on the cultivator that allows thecultivator to move side to side independently. He cancultivate as fast as 10 mph. He may use a rotary hoe forweed control up to 4 times if needed. A Melroe springtooth harrow is sometimes used, especially when theweeds are too big for the rotary hoe and if grass is tooabundant. This tool can be used on soybeans as tall as10”.
  • 41. Essentially all of the farmers plant small grains
  • 42. Frost seeded cloverthe most tried and true cover cropping system in the Midwest region
  • 43. Where are the soybeans?? Traditional organic weed management often comes up short during wet years
  • 44. Days Suitable for Field Work http://agebb.missouri.edu/mgt/fieldwork.htm Timely field operations are especially important in organic farming systems The past 3 seasons have had far fewerdays suitable for field work than normal
  • 45. September OctoberTillage System Experiment at the WIU organic research farm November January
  • 46. Options for rolling cover cropsRodale design Our roller in 2010 Cultimulcher
  • 47. Early June 1 week later
  • 48. ~2 weeks after planting
  • 49. JulyAugust late September
  • 50. Early NovemberPlot yields ranged from 51.6 to 58.6 bu/ac No significant differences between systems
  • 51. November 2010 Significant foxtail pressure but almost no broadleaf weedsPlot yields ranged from 42-52 bu/ac
  • 52. Early June 2011 We planted beforerolling in one set of plots
  • 53. 15’ wide roller built by a local farmer
  • 54. Mid-June 2011
  • 55. Early July 2011
  • 56. Our conventional-till beans are looking good, right?Unfortunately, there were lots of in-row weeds :-<
  • 57. August 2011
  • 58. November 2011 No-till bean plots averaged 43 bu/a ~ 10 bu/a higher than then nexthighest treatment in this experiment
  • 59. 7/17/2010 planting After ~ 300% of normal rain in May, June andJuly 2010 we ended up planting sunflowers on most of our acres planned for corn
  • 60. Both 2010 planting dates matured with an average yield 7/29/2010 planting> 1500 lbs/a. We planted sunflowers on 7/7 in 2011 andplan to continue using sunflowers as a strategy forcleaning up fields with high weed pressure.
  • 61. Cereal rye inter-seeded with soybean for in-row weed control at the Allison Farm No significant differences in yield between 20 and 40 lbs/a of rye in row vs. 60 lbs broadcast vs. control (all trt means > 40 bu/a) Cereal rye and several other CC species that requirevernalization will be planted over soybeans rows using the insecticide boxes on our planter in 2012
  • 62. Do all parts of your farming systems contribute to effective weed management?