I shared this presentation with a group of organic soybean producers in northern IA on 2/5/2011

1. Organic weed management for soybeans
Joel Gruver
WIU Agriculture
J-gruver@wiu.edu
(309) 298 1215

2. Organic weed management
Crop
Adapted from Bailey and Lazarovits (2003)

3. Conservation Augmentation
3 broad goals of
Activation
ecological
management Suppression

4. A nice flush of weeds ready for termination
What can we do to maximize this flush?
Not all tillage operations have the same effect

5. Terminating spring planted oats with a soil finisher
~ 3 weeks before planting corn
GOAL = biological activation and suppression

6. 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

7. Who is sleeping in your soils?

8. 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

9. No pre-plant tillage for this experiment
Ridge till and No-till
soybean strips
will require no pre-plant
tillage this spring

10. Effective
Integration of
organic weed =
many little hammers
management
No one hammer is likely to provide acceptable weed control

11. Cropping system strategies
vs.
Direct control strategies

12. Effective strategies disrupt weed life cycles

13. Cropping system strategies
Crop rotation
Tillage rotation
Cover cropping
Crop management
Fertility management
Manure management
Field/equipment/seed sanitation

14. Optimize crop establishment to
maximize crop competitiveness
-Select a well adapted variety (maximum leafiness
and rate of canopy closure)
-Delay field work (soil must be warm enough for
rapid crop emergence)
-Prepare a good seed bed (start out clean)
-Reduce row spacing and increase populations
-Row fertilizer?

15. Preventive management
• Flush soil seed bank with fallow periods
• Walk crops
• Employ alternative equipment for mowing,
pulling weeds
• Weedy crops -> forage or cover crops

17. 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 describing
equipment for direct control of
weeds

18. Blind cultivation
Blind cultivation
normally occurs before
the crop emerges or
shortly after emergence

21. Are you getting full performance out of your rotary hoe?
30’ rotary hoe

24. Rotary hoes and flex-tine weeders
are most effective when the soil has a crust
Some crop damage is inevitable but care should be
taken to avoid times when crop is most fragile

25. Inter-row cultivation

29. Guidance systems are available to
increase accuracy and reduce operator
stress during cultivation

30. Innovative farmers have developed a wide range of cultivation tools

31. Fall planted small grains are very
competitive against weeds

32. Do you see a cover crop?

33. Do you see a cover crop?
Frost seeded clover
the most tried and true
cover cropping system
in the Midwest region

34. Frost seeding
options Sweet
clover
Mustard

35. We are going to try frost
seeding mustard for the
first time this spring

36. Klaas and Mary Martens,
organic innovators in Central
NY State, are reporting
excellent results with frost-
seeded confectionary mustard
ahead of dry beans

37. 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

39. Pioneering work
by Jeff Moyer at
the Rodale
Institute
has sparked
considerable
interest across
the country

40. Mechanical innovation
Innovation all
is key to making
across the US
conservation tillage
systems work

41. September October
Tillage System Experiment at the WIU organic research farm
November January

42. March April
Early May Late May

43. Options for rolling cover crops
Rodale design
Cultimulcher

44. Early June
1 week later

45. ~2 weeks after planting

46. July
August late September

47. Early November
Plot yields ranged from 51.6 to 58.6 bu/ac
No significant differences between systems

48. November 2010
Significant foxtail pressure
but almost no broadleaf weeds
Plot yields ranged from 42-52 bu/ac

49. Bio-strip till
September 2008

50. Early September 2009

51. Early November 2009
Tillage radish on 30” rows with oats on 7.5” rows

52. Radish planted on 30” rows using milo plates in mid-
August 2010

54. S. Carruthers

55. November 2010
Radish planted in volunteer
cereal rye

56. Wheat + radish trial November
2010

57. July 17 planting

58. July 29 planting

59. Weed management for organic row crops

60. Weed management for organic row crops
I recently received a grant to support
documenting the weed management practices
used by top-notch organic weed managers
How should we go about finding top-
notch organic weed managers?
What questions should we ask them?