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I shared this presentation with a group of organic soybean producers in northern IA on 2/5/2011
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Adapted from Bailey and Lazarovits (2003)
Organic weed management
Crop
3 broad goals of ecological
management
Activation
AugmentationConservation
Suppression
A nice flush of weeds ready for termination
What can we do to maximize this flush?
Not all tillage operations have the same effect
Terminating spring planted oats with a soil finisher~ 3 weeks before planting corn
GOAL = biological activation and suppression
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
Who is sleeping in your soils?
Do any of you have experience with flame weeding?
Dennis Leutke in MN and Larry Shrock in MO are experts
Terminating weeds without awakening sleeping seeds
No pre-plant tillage for this experiment
Ridge till and No-till soybean strips
will require no pre-planttillage this spring
Effectiveorganic weedmanagement
Integration of many little hammers
No one hammer is likely to provide acceptable weed control
=
Cropping system strategiesvs.
Direct control strategies
Effective strategies disrupt weed life cycles
Cropping system strategies
Crop rotationTillage rotationCover cropping
Crop managementFertility managementManure management
Field/equipment/seed sanitation
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?
Preventive management
• Flush soil seed bank with fallow periods
• Walk crops
• Employ alternative equipment for mowing, pulling weeds
• Weedy crops -> forage or cover crops
ABCs of mechanical andcultural 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
Blind cultivation normally occurs before
the crop emerges or shortly after emergence
Blind cultivation
30’ rotary hoe
Are you getting full performance out of your rotary hoe?
Rotary hoes and flex-tine weedersare 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
Inter-row cultivation
Guidance systems are available to increase accuracy and reduce operator
stress during cultivation
Innovative farmers have developed a wide range of cultivation tools
Fall planted small grains are very competitive against weeds
Do you see a cover crop?
Do you see a cover crop?
Frost seeded clover
the most tried and true cover cropping system in the Midwest region
Sweet clover
Mustard
Frost seedingoptions
We are going to try frost seeding mustard for the
first time this spring
Klaas and Mary Martens, organic innovators in Central
NY State, are reporting excellent results with frost-
seeded confectionary mustard ahead of dry beans
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
Pioneering work by Jeff Moyer at
the Rodale Institute
has sparked considerable
interest across the country
Innovation all across the US
Mechanical innovation is key to making
conservation tillage systems work
September October
November January
Tillage System Experiment at the WIU organic research farm
March April
Early May Late May
Options for rolling cover crops
Rodale design
Cultimulcher
Early June
1 week later
~2 weeks after planting
July
August late September
Early November
Plot yields ranged from 51.6 to 58.6 bu/ac
No significant differences between systems
November 2010
Plot yields ranged from 42-52 bu/ac
Significant foxtail pressure but almost no broadleaf weeds
Bio-strip till
September 2008
Early September 2009
Tillage radish on 30” rows with oats on 7.5” rows
Early November 2009
Radish planted on 30” rows using milo plates in mid-August 2010
S. Carruthers
Radish planted in volunteer cereal rye
November 2010
Wheat + radish trial November 2010
July 17 planting
July 29 planting
Weed management for organic row crops
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?
