Sustainable use of your grassland herbicides

THE SUSTAINABLE use of grassland pesticides is going to become a major area for farmers into the future, particularly as we are recently hearing more about the EU farm to fork strategy and the CAP post-2023.

The draft proposal of this strategy is for a 50-per-cent reduction in pesticide use by 2030. It is therefore essential for farmers to take great care and follow best practice procedures when using pesticides.

The chemicals causing the greatest problems are MCPA, used widely for controlling rushes and 2, 4-D. These compounds are highly soluble in water and more persistent in the environment.

Two other herbicides with high usage and causing increasing concern are Fluroxyphyr and Glyphosate (such as Roundup, Gallup etcetera).

Herbicides can contaminate surface or ground water by point sources or diffuse sources. Point sources are losses in the farmyard, such as leaks from storage and spills from mixing, filling and washing. Diffuse sources are losses in the field due to spray drift, surface runoff and drainage.

Given the dry weather currently, conditions are ideal for spraying, but some key areas that we can focus on when spraying to reduce any potential contamination include the following:

The applicator must be a trained Professional Pesticide User and have a PU number in order to be able to use pesticides on their farm. Proper records need to be also kept of where spray has been applied and at what rates. Application equipment must be well maintained, regularly calibrated and tested every three years. Weed lickers and smaller boom sprayers (less than three metres) will be included in the testing regulation by end of 2020.

Alternative methods of controlling weeds such as topping, drainage, sward improvement, and so on could be looked at. A planned control strategy can justify spraying if other options have been explored first. These are important principles of Integrated Pest Management (IPM), a key requirement of the Sustainable Use Directive (SUD).

For the operator, you should always use appropriate Personal Protective Equipment (PPE) including a fully protective suit, mask and gloves.

Minimise transport risks from retailer to farm and from farm to field as accidents can happen, and also because you don’t want sprays leaking during transport.

Always read and follow label instructions (correct use, correct rate, correct time). Always use the approved application method (for example, MCPA is not licensed for use in a weed licker/wiper or knapsack). Choose the lowest-risk strategy where water bodies are a risk.

Take care to avoid spills, especially when handling the concentrated product. It is best to have a containment system in place to catch spills eg drip tray.

You should never fill the sprayer directly from a watercourse. Sprayers should be filled where losses to water bodies cannot occur. Be aware of the location of water bodies on the farm. Take note of the buffer zone for the chemical and comply with the specified unsprayed strip (generally one to five metres)

Comply with the safeguard zones for the protection of drinking-water abstractions from ground water.

Spray when conditions are suitable: on a calm day, vegetation dry, no heavy rainfall for more than two days, with land reasonably dry and a young crop of healthy weeds.

Do not apply on waterlogged or poorly draining soils that slope steeply towards a water body, or any other vulnerable area leading directly to surface or ground water.

Another potential high-risk pathway is field drains filled towards the surface with stone. In this scenario, avoid band spraying within five metres of the drain. Spot spraying is a safer option.

When finished with containers, ensure you dispose of them properly by triple rinsing the container, and add the rinsate to the sprayer.

Spray the tank washings (internal rinsing) and clean down the external parts of the sprayer in the field.

Don’t discard sprayer washings on a yard or gravel area as it can potentially enter a water body.

These are just some pointers on how to minimise sprays from entering watercourses, to ensure longer term availability and sustainability of their uses.