Integrated Weed Management (IWM)
Building profitable and sustainable rice farming systems through better fallow management
Published: August 2027
What is integrated weed management?
Integrated weed management (IWM) is a long-term approach to weed control that combines multiple tactics to reduce weed populations and minimise herbicide resistance over time.
Rather than relying on a single tool, such as herbicides, IWM uses a combination of chemical, cultural, biological and mechanical strategies to manage weeds while protecting long-term productivity.
“Integrated weed management is essentially an approach where you're not just relying on one particular tool in the toolkit.” - Meg Brown, Elders Griffith Broadacre Agronomist
What does integrated weed management look like?
Successful IWM programs use a range of complementary practices to reduce weed pressure, protect valuable chemistry and improve whole-farm profitability.
Cover crops
Suppress weeds through crop competition and ground cover.
Improve soil structure and reduce erosion.
Increase soil organic matter and nutrient cycling.
Provide opportunities to introduce additional herbicide modes of action.
Herbicides
Rotate herbicide modes of action to delay resistance.
Use residual herbicides strategically to control weeds before they emerge.
Target the right weed at the right growth stage.
Ensure the spray boom is set up to minimise drift and maximise the right amount of chemical getting to the target.
Strategic cultivation
Use cultivation where appropriate to manage specific weed species.
Understand how cultivation affects weed seedbank dynamics and future weed pressure.
Crop rotation
Increase weed control options by diversifying herbicide programs.
Create additional opportunities for seedbank management through hay, silage, green manure or brown manure crops.
Spread production and seasonal risk across the farming system.
Early intervention
Target weeds while they are small and actively growing.
Aim to control emerged weeds within 10 days of germination, particularly during summer fallows.
Reduce competition for water and nutrients before weeds become established.
Soil and water management
Reduce reliance on single herbicide groups and repeated cultivation.
Improve soil health and water use efficiency.
Maintain more soil moisture and nutrients for future crops.
Why should IWM be a priority?
Every weed that survives has the potential to set seed, increase future weed pressure and contribute to herbicide resistance.
Effective fallow weed control delivers benefits well beyond the current season by:
Conserving valuable soil moisture.
Retaining plant-available nitrogen and nutrients.
Reducing weed seedbanks over time.
Improving planting conditions.
Supporting more effective herbicide programs.
Increasing future rotational opportunities.
Weeds growing during fallow periods compete directly with future crops for water, nutrients and profitability.
"Start early with your fallow management. Don't rely on one particular tool. Give yourself the opportunity to have a couple of goes at it."
Effective fallow management today helps set up the next crop for success.
What role can cover crops play?
Cover crops are becoming an increasingly valuable tool within integrated weed management programs.
Benefits may include:
Weed suppression through crop competition.
Additional herbicide options within the farming system.
Improved soil structure and soil health.
Increased soil organic matter.
Reduced erosion and topsoil loss.
Improved nitrogen cycling, particularly from pulse species such as vetch.
Greater farming system resilience.
Cover crops should be viewed as another tool in the toolbox rather than a standalone weed control strategy.
Before returning a paddock to rice
Take time to understand the history of each paddock before finalising your weed management strategy.
Checklist:
✓ What weed species have been present in previous crops or fallows?
✓ Which herbicide modes of action have been used in recent seasons?
✓ Are there any potential herbicide resistance concerns?
✓ Are there plant-back restrictions from previous residual herbicides in your rotation?
✓ What is the current weed seedbank likely to look like?
Looking ahead to a non-ponded rice future
As rice production systems continue to evolve, weed management will become increasingly important.
Reduced ponding periods and changing water management practices may create opportunities for different weed species to persist and thrive. This means growers will need to place greater emphasis on:
Early weed control.
Fallow management.
Diverse weed control strategies.
Protecting herbicide effectiveness.
Key takeaways
Integrated weed management uses multiple tactics rather than relying on a single control method.
Successful weed management starts with a plan and a long-term view of the farming system.
Early intervention is the most cost-effective approach to controlling weeds.
Effective fallow management conserves water and nutrients while reducing future weed pressure.
Weed management decisions should be tailored to the weed species present, soil type and planned crop rotation.
The actions taken today will influence productivity, profitability and weed pressure for seasons to come.
“Just be mindful of what you're doing in fields is going to ultimately impact the following season.”