1. Sustainable Weed Management Strategies

2. Know your Weeds ID your weeds in your field
Be sure you want to get rid of it
They do have a role:
Holding water
Creating organic matter
Providing cover
Habitat for beneficial insects
“Weeds are plant we have not yet found a use for.”
“Weeds are any plant growing in a space intended for another.”
A good on-line identification tool for weeds can be found on the UC Davis site:

3. Tools for Control Don’t bring weed seeds onto the farm
Nutrients brought onto the farm
Raw manure will have seeds
Instead of manure -- Use compost!
Turn the pile often to get the temp even throughout and kill seeds
Be careful of source material
Mulches
Don’t use hay
Straw is better

4. What can I compost? Animal manures Straw, hay Vegetable matter
Yard debris
Wood shaving/chips
Newspaper
Fruit and vegetable wastes

5. Compost non-animal materials
Organic Production
Compost non-animal materials
Plant residues, etc
No specific composting regulations
With composting of plant materials in organic systems, there are no specific regulations

6. Compost with animal materials
Organic Production
Compost with animal materials
Regulations for using compost that contains animal materials are more specific.
Required minimum temperatures
Required turning times
Required C:N ratio
Requirements for compost that will be used on organic systems IF made with animal materials:
Initial Carbon to Nitrogen ratio 25:1 – 40:1
In vessel or covered oF, 3 days, All portion of pile meets this temperature.
Turned windrow oF, minimum 15 days with 5 turns.

7. Don’t let weeds go to seed!
Early cycle weed control
Is it worth continued harvesting from a field to justify continued weed management?
Hand weeding is expensive
$200-$700/Ac
If you have weeds – stop the cycle. It is easiest to get rid of them while seedlings – light cultivation or other methods.
At some point – if weed control costs more in labor than a particular field crop is worth – you need to weigh cost to benefits. It might be more economical to till the crop under and get the weeds under control - just a thought…

8. Cultivating Expensive to control in row Cultivate on both sides of row
Shallow tillage
Brings smallest amount weeds to the top
Planting techniques will help the crop out compete the weeds
Shallow cultivation between rows when weeds are small can be very effective. In row weeding is much harder and you set up your crop to be more competitive by your planting techniques
Precision planter
Get a uniform stand
Shallow planting
Deeper the planting, the longer for germination
Distance between row
Shade out weeds
Plant dense - set up a bed like system

9. Cover crop the year before
Use cover crop for weed suppression
Shallow tillage
Brings smallest amount weeds to the top
Cover crops the season before planting the crop will often smother weeds or out compete them so you have a reduced stand for planting.
Shallow tillage
Cover cropping with winter peas for organic dry land wheat production.

10. Transplants Give 4+ week jump on weeds
Plant at the right planting density can give you weed free plots
Sometimes transplants are set in a straw mulch or low growing cover crop mulch.

11. Irrigation Drip irrigation is more water efficient
Also by directing water to the crop it minimizes weed germination and reduces need to cultivate
Irrigation can also influence weed management.

12. Timing of Cultivation Cultivate as soon as you can
Small weeds easier than big weeds to remove
Do not irrigate right after cultivation
Depth of cultivation
Depends on weed species
Don’t water after cultivation because you want the weed seedlings you brought to the surface to desiccate.

13. Equipment
A large part of controlling weeds is recruitment of the appropriate technology
The following is a short survey of the available equipment.

14. Hand Tools
Photos provided by D. Muehleisen

15. Hand Tools
Photos provided by D. Muehleisen

16. Flamer
Above is a picture of a flamer that is a perennial crop model for weed control in berms. Different models are available for beds or rows.

17. Lely Tine Weeder
Specially suitable for weeds with underground rhizomes
Bring rhizomes to surface and causes them to desiccate
Timing is critical
Specially suitable for weeds with underground rhizomes
Brings rhizomes to surface and causes them to desiccate
Timing is critical

18. Bush hog Rotary mower Cutting cover crop
Mowing weeds before setting seeds
Operates like a rotary mower
Used for cutting cover crop or mowing weeds before setting seeds
Photos provided by D. Muehleisen

19. Summary Know your weed problems Don’t introduce new weeds
Eliminate spread of existing weeds
Compete with them – cover crops, the main crop (spacing, timing, etc.)
Use a variety of tools depending on situation (cultivators, flamers, hand tools)

20. Reading and Assignment
Reading for Next Week
New Organic Grower - Chapter 24
Assignments
Complete Pest Management and Weed Management in Whole Farm Plan
Compile the elements of sections I, II, IV and V from the Whole Farm Plan Template.
Bring in a hard copy for review next week