As farmers gear up for the autumn planting season, the importance of soil health, weather conditions, and the right adjuvant in optimising pre-emergence herbicide performance cannot be overstated. At Interagro, we’re here to guide you in making the most of your herbicide applications this season.
Following a notably wet year, ensuring effective residual herbicide application and maximising their longevity in the weed germination zone, is vital for achieving a strong weed-free start to the growing season.
Pre-emergence residual herbicide programmes represent a critical element of effective weed management strategies, reducing reliance on less effective contact herbicides post-emergence. But with the performance of soil-acting residual herbicides highly dependent on good soil structure, and favourable weather conditions following application, weed control strategies could be under serious pressure if farmers fail to take action when conditions take a turn for the worst.
Key Areas:
- Understanding residual herbicides
- Steps to maximise residual herbicide performance
- Why use a residual herbicide adjuvant
- Why farmers choose Backrow Max to secure their fields
- Experience the Backrow Max difference
Understanding residual herbicides
Pre-emergence residual herbicides are designed to control weeds before they emerge from the soil. They provide a crucial layer of protection to crops to prevent weeds competing for space, moisture, nutrients and sunlight.
However, the effectiveness of residual herbicides can be significantly reduced when conditions become excessively dry or excessively wet after application. This can be down to poor activation and uptake in dry conditions and in wet conditions, due to runoff, poor retention and dilution.
Steps to maximise residual herbicide performance
To maximise the performance of residual herbicides this autumn, we would encourage farmers to focus on five key areas to get the most from their pre- and peri-emergence applications:
Step 1 – PREPARE THE SOIL WELL
The foundation of effective soil-acting residual herbicide application and efficacy, lies in good soil structure. Assess soils before drilling and improve soil conditions where necessary by:
- Ensuring good tilth: A well-structured soil, free from any surface crust, promotes even distribution of herbicides across the surface.
- Addressing compaction: Removing compacted layers allows for better water and herbicide infiltration, ensuring that active ingredients reach the weed germination zone.
- Enhancing porosity: Healthy porous soils retain moisture better, supporting crop growth and herbicide efficacy.
Step 2. MONITOR SOIL MOISTURE
Adequate soil moisture levels play a critical role in the activation and performance of residual herbicides. Ensure that sufficient moisture is present after application:
- Residual herbicide activation – requires moisture to move herbicides from the soil surface to the weed germination zone 5cm lower down.
- Herbicide uptake into weeds – is dependent on good moisture levels for efficient desorption from soil particles.
- Consider delaying pre-ems in a dry spell – especially if there is insufficient moisture for weeds to germinate shortly after application.
Step 3. AVOID HEAVY RAINFALL IMMEDIATELY AFTER APPLICATION
Schedule pre- and peri-emergence applications when rain is forecast but avoid periods of heavy rain shortly after spraying to ensure herbicides have sufficient time to bind to soil particles, particularly in light soils:
- Herbicide retention in the weed zone – is crucial to ensure ongoing control of germinating weeds. Steer clear of heavy rainfall shortly after application to avoid herbicides being washed out of the weed zone, resulting in a sub-lethal dose and reduced residual activity.
- Crop and groundwater safety – can be at risk in adversely wet conditions if herbicides are washed prematurely from the weed zone. Stay informed about local weather conditions and adjust your application timing accordingly.
step 4. APPLY ON CALM DAYS
Choose days with low wind speeds to minimise drift and ensure even herbicide application across the soil target:
- Even spray coverage – is crucial to create an effective barrier against weed emergence.
Step 5. INCORPORATE ADJUVANT BACKROW MAX
Backrow Max is a proven adjuvant that enhances the performance of pre-emergence herbicides, providing multiple benefits:
- Improved moisture retention – Backrow Max helps maintain soil moisture levels, reducing reliance on rainfall for herbicide activation and promoting consistent uptake by germinating weeds.
- Enhanced binding – It improves the binding of herbicides to soil particles, prolonging their concentration in the weed germination zone and enhancing effectiveness in wet conditions.
- Drift minimisation and improved deposition – Backrow Max reduces the number of fine droplets susceptible to drift and the number of very coarse droplets prone to bounce, resulting in more uniform distribution across the soil surface and a stronger barrier to weed emergence.
Why use a residual herbicide adjuvant
Residual herbicide adjuvants are products that can be co-applied with residual herbicides to improve their performance. In suboptimal weather and application conditions adjuvants can be a crucial addition to enhance their effectiveness. Here’s how they can help:
- Extended weed control: A residual herbicide adjuvant can help prolong the effectiveness of your herbicide, providing extended protection against challenging weeds. This is especially crucial when soils become wetter and rainfall more frequent.
- Improved coverage: Adjuvants can enhance herbicide deposition and distribution across the soil surface, ensuring better coverage. This leads to more effective weed suppression, even in tough conditions.
- Cost Efficiency: By improving the efficacy of your costly herbicide applications, you can potentially reduce the number of treatments needed throughout the season, saving you both time and money.
- Enhanced Crop Establishment: The use of an adjuvant can minimise the risk of herbicide damage to crops, supporting better crop establishment and growth.
- Environmental Benefits: Using a residual herbicide adjuvant can help minimise the risk of herbicides leaching to groundwater, reducing contamination. This supports water stewardship measures and benefits the environment.
Why farmers choose Backrow Max to secure their fields
Farmers using Backrow Max can expect significant improvements in herbicide performance, even under suboptimal conditions. Here are some key findings:
- Increased Herbicide Retention: Studies show enhanced retention in the top 5cm of soil, with improved performance across various herbicides: 7% more clomazone; 8% more pendimethalin; 6% more Luximo.
- Enhanced Residual Activity: Up to a 17% improvement in weed control for black-grass, ryegrass, and brome.
- Increased Moisture Retention: A 33% boost in water retention enhances herbicide efficacy in dry seedbeds.
- Reduced Crop Phytotoxicity: A 20% reduction in chlorosis and increased wheat emergence by up to 29 plants per sqm.
Experience the Backrow Max difference
Join the many farmers who have already experienced the benefits of Backrow Max.
Backrow Max can be purchased through Agrii in the UK.
For more information, download our latest guide here – for independent trials results with the latest residual herbicides, farmer case studies and more. You’ll also find an extensive list of approved crops.
Please get in touch with Stuart below if you require any technical assistance or further information.