Weed management in organic agriculture......regards manjunath

1. Weed management in
Organic Agriculture
Manjunatha, G.A

2. Tools for prevention
Avoid the entry of weed seeds onto the farm through
• Manures
• Mulching material
• Intercultivation equipments
• Animals
• Water etc.
Instead of using manure - Use compost.

3. Different practices to control
• Cultural
• Mechanical
• Biological
• Chemical (organically approved)
Liebman and Gallandt, 1997

4. Cultural Practices
Improve crop competitiveness
• Increase crop density through narrow row
spacing and increased seeding rate .
• Use transplants, rather than seed.
• Choose competitive crop cultivars.
• Manage fertility according to crop needs; avoid
excess application.
• Spot application of fertilizers.

5. Intercropping
• Having different plant types growing together enhances weed
control by increasing shade and increasing crop competition
with weeds through closer crop spacing.
Ex:
• soybean +wheat
• Sugarcane + finger millet
• Sunflower + groundnut

6. Sugarcane+finger millet
Sunflower+groundnut

7. Crop Rotations
• Weeds tend to infest crops with similar life cycles
• Crop rotations limit the buildup of weed populations and
prevent major weed species.
• Altering, narrowly spaced crops with closely spaced crops,
shallow rooted with deep rooted crops, cold with warm season
crops.

8. Allelopathy
• Allelopathy crops are especially useful because they have the ability
to suppress other plants that attempt to grow around them.
• Rye is one of the most useful allelopathic cover crops which kills
weeds like ragweed (by 43%), pigweed (95%), and common
purslane (100%).
• North Carolina researchers investigated combinations of herbicide
use and cover crop plantings on weed control and reported Rye and
clover showed the highest weed control without herbicides.

9. Smother Crops
• Prevent seeds from germinating by blocking light, can smother
out some weeds.
• In northern states, oats are commonly planted as a “nurse
crop” for alfalfa, clover. The oats grow between in the place of
weeds and avoid weed emergence.
• Ex: Mustard as cover crop in Ragi.

10. mustard as cover crop in ragi

11. Weeding manually
• Hand weeding
• Removing of weeds manually before the flowering of weeds to
avoid weed establishment.

12. Diff hand Tools

13. Irrigation
• Drip irrigation is more water efficient .
• Also by directing water to the crop it minimizes weed
germination and reduces need to cultivate.

15. Mulching
• Covering the surface of soil to avoid the entry of sunlight by
using locally available materials like straw, plastic, papers,
wood pieces, dry leaves etc.
• Prevent seeds from germinating by blocking light, can smother
out some weeds.

16. Wood chips Dry Leaves
Biodegradable paper pieces
Straw

17. Straw as mulching material in onion crop

18. Mechanical methods
• Cultivation of the soil with a variety of different tools can
control emerged weeds and disrupt weed reproduction cycles.
• Cost effective
• Time consuming

19. High-tech tools
Field cultivator High residue cultivator
High-residue cultivator Flex-tine weeder

20. Flexible spider weeder Badger weeder
Torsion weederRolling weeder

21. Basket Weeder

22. Flame weeding
• Burning of weeds by flame.
• Intense heat causing the cell sap to expand and disrupt cell
walls.
• Pre-emergent, and post-emergent flame weeding has been
successful in a number of crops.
• Flaming has generally proved most successful on young
broadleaf weeds.
• It is reportedly less successful on grasses.

23. Flame weeder

24. Solarizing the soil
Steps:
• Cultivate soil properly
• Irrigate soil completely
• Put plastic over the soil
– Weed get cooked

26. Breeding for Crop Competitiveness and Weed
Suppression
• Plant breeding is one way to improve weed management in
organic systems.
• Development of crops with increased competitive ability and
enhanced weed suppressive qualities .
• Crop qualities that promote crop competitiveness include early,
rapid establishment in less favorable conditions, crop structures
that limit weed access to light and nutrients ,increased plant
hardiness etc.

27. Bio Herbicide
Corn gluten meal (WeedBan and Corn Weed Blocker)
• It has been used successfully on lawns and high-value crops.
• pre-emergent herbicide.
Commonly based vinegar or lemon juice or clove oil ingredients
• Burnout : 23% acetic acid.
• Bioganic: 10% acetic acid plus clove oil and thyme oil.
• MATRAN & Weed Bye Bye etc
• post-emergent herbicides.

29. Weeder Geese(ducks)
They are particularly used as grass weeders
in a variety of crops.

30. Crops: cotton, strawberries, tree nurseries,
corn , fruit orchards, tobacco, potatoes,
onions, sugar beets etc.

31. Thank you….