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

1. Organic weed management in field crops
Proven and new approaches
Dr. Joel Gruver
Western Illinois University
j-gruver@wiu.edu

2. PRECISION
Currently only available upon request
Will soon be downloadable
from our website
http://www.wiu.edu/cbt/agriculture/farms/organic/

3. High tech precision vs. attention to detail

4. In 2012, I witnessed a new level of attention to detail

8. 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

10. Steel in the Field shows how
today's implements and
techniques can control weeds
while reducing—or
eliminating—herbicides.
In practical language, Steel in
the Field presents what
farmers and researchers have
learned in the last 20 years
about cutting weed-control
costs through improved
cultivation tools, cover crops
and new cropping rotations.

11. STEEL in the FIELD
Row crop farmer profiles
Dryland farmer profiles

13. 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 to
winter’s wrath. He makes a second fall pass if weeds begin to
regrow, or if quackgrass is a problem.

14. 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 field
cultivator outfitted with 9-inch sweeps. He makes a
second pass if weed pressure is heavy and if he can
delay planting.

15. Terry uses a Seed-Right hoe drill

17. Crop Rotation on Organic Farms:
A Planning Manual provides an
in-depth review of the applications
of crop rotation-including
improving soil quality and health,
and managing pests, diseases, and
weeds. Consulting with expert
organic 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 and
Eastern Canada but is worth a look

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

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

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

22. 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 feeding
We had near perfect stands in every other field

23. 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

24. Who is sleeping in your soils?

25. 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

26. Cropping system strategies
vs.
Direct control strategies

27. Effective strategies disrupt weed life cycles

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

29. Optimizing crop growth 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?

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

31. Hopefully it doesn’t really take 15 years
for preventative management to pay

32. Well established fall planted small
grains are very competitive
against weeds

33. Do you see a cover crop?

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

35. Frost seeding
options Sweet
clover
Mustard

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

38. Results would probably be opposite during a normal or wet year
Preceded by radish :-<

39. 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

40. Pioneering
work by Jeff
Moyer at the
Rodale
Institute
has sparked
considerable interest
in organic no-till
across the country

42. Innovative farmers
Innovation all
have built lots of
across the US
interesting looking
rollers

43. Some times its best to make do with
what you already have
Cultimulcher
Front mounted Rodale roller

44. October 2008
Cereal rye drilled at 60
lbs/a in late August
Our experience is that a strong stand of rye is
much more important than roller design

45. Early June 2009
1 week later

46. ~2 weeks after planting

47. July
August late September

48. Early November 2009
No-till, bio-strip-till and conventional till plot
averages ranged from 51.6 to 58.6 bu/ac
No significant differences between systems

49. We planned a ridge-till vs. no-till comparison for 2010

50. May 2010

51. 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

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

53. June 2011

54. August 2011

55. November 2011
The NT bean plots yielded
~10 bu more than the best
tillage system plots

56. April 2012

57. Planting into 5-6’ tall rye on May 11

58. Double drilled with 4” offset

59. June 2012

61. Our 2012 NT bean yields ranged from
~ 30 to ~ 60 bu/a

62. 60-70
bu/a

63. In July 2012, we undercut several fields of small grain stubble
using a Hinniker no-till cultivator and a tractor with RTK guidance

67. Cover crop cocktail
Fallow strip no-till drilled after
undercutting

68. Triple S mix
Sunflowers, Soybeans & Sunn hemp

69. 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

70. July 17 planting

71. 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

73. Steering (Autosteer)
Vehicle control
Steering
(assisted steering)
Precision
Mechanization Steering
(passive)
Implement Steering
control (active)
Planter row unit
control

74. Strip intercropping
230 bu/ac in
2010
Jacob

87. Exciting developments are happening but the foundation of
successful weed management in organic row crops
will continue to be healthy crops and healthy soil