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Key Knowledge: Principles of Integrated Weed Management
Key Knowledge: Principles of Integrated Weed Management
The goal of IWM is not to eradicate every single weed on a property, but to use a combination of methods to keep the weed population at a level where it does not cause significant economic loss.
PRACTICE Use the following informtion to add to your table and notes.
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Cultural and Preventive Controls
Cultural and Preventive Controls
This is the most important part of any plan. It involves changing the farming system to stop weeds from establishing in the first place.
Biosecurity: Cleaning machinery, boots, and vehicles when moving between different areas of the farm to prevent seed movement.
Crop Rotation: Changing the species of crop grown in a field each year to disrupt the life cycle of weeds that prefer a specific environment.
Competitive Sowing: Increasing the seeding rate or using narrower rows so the crop grows thick and fast, shading out weeds before they can establish.
Physical and Mechanical Controls
Physical and Mechanical Controls
These methods involve physically removing the weed or destroying its ability to grow.
Hand Weeding: Effective for small-scale horticulture or high-value crops where precision is needed.
Tillage and Cultivation: Using machinery to turn over the soil and pull out weed roots.
Harvest Weed Seed Control: Using a seed destructor on a harvester to crush weed seeds as the crop is being picked, preventing them from falling back into the soil.
Photo by Chad Stembridge on Unsplash
Photo by Ugo Mendes Donelli on Unsplash
Biological Controls
Biological Controls
This involves using a living organism to manage a weed population.
Targeted Grazing: Using sheep or goats to eat specific weeds (like gorse) before they flower.
Beneficial Insects: Releasing insects that eat the weed to weaken it, such as the gorse spider mite.
Chemical Controls
Chemical Controls
This should be the last line of defense.
Selective Herbicides: Using chemicals that kill the weed but do not harm the crop.
Spot Spraying: Applying chemicals only to the specific areas where weeds are present rather than spraying the entire field.
Resistance Management: Never using the same chemical group twice in a row to ensure weeds do not become immune to the treatment.
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PRACTICE
Why should cultural control be considered first?
Explain how cleaning a tractor before it enters a new paddock is a form of biosecurity.
If a farmer only uses chemical sprays every year, what is the likely long-term outcome for the weed population?
PRACTICE
Try doing an audit of your school's Ag Hort area. If you are really lucky, you might have a farm to work with but otherwise, see if you can find any of the 3 weeds we are studying within your school. Check the biosecurity and see if it could be improved or if it is already a model example of what to do. Remembering that not all precautions are suitable everywhere. (So no judgement please, unless you are willing and able to fix the situation!)
Here is the audit we are using for our school
Once you finish the paper audit, you should take a photo of your most significant finding (e.g., a weed setting seed or a successful sticky trap) and upload it to your Google Classroom. This will provide evidence for the key skill of demonstrating practical tasks.
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