In order to minimise at best the risk of water contamination with spray drift plant protection products may only be used with appropriate precaution measures. These precautionary instructions are on the label and must be followed by any user. In case an active substance is found in surface water the competent authorities may restrict the use of a product or prohibit its use altogether.
Likewise, all professional users must stick to application dosages and buffer zones that are indicated on the product label.
A buffer zone is a non-treated strip along surface water.
Surface water is meant to be any standing or running water course at soil surface. Hence,these are rivers, ditches, ponds...and also artificial water bodies such as collection channels etc.
The vegetation on a buffer zone grown to protect water from spray drift can be any type of vegetation.
The width of a buffer zone is the minimal distance to observe between the last treated crop row and the upper bank.
In Belgium, buffer zones are set at 2-30 m depending on the product's toxicity with regard to aquatic organisms. For highly (aqua)toxic products additional risk mitigation measures have to be applied.
Buffer zones are also set along "sensitive" areas.
In any case a non-treated 1m minimum zone for applications directly towards the soil or for any other application type susceptible to expose non target aquatic organisms or a non-treated 3 m minimum zone for other applications not directed directly towards the soil (e.g. orchards) with regard to surface water is mandatory.
The federal provisions with regard to buffer zones to protect surface water are set out in Royal Decree of 19th March 2013.
In line with the Water Framework Directive 2000/60/EU and the Sustainable Use Directive 2009/128/EU the regions may impose additional measures to protect surface water. However, the federal requirements in terms of buffer zones in line with the royal decree are to be found on the product labels.
Use of additional risk mitigation measures for products that are highly toxic for the aquatic environment
These additional measures concern applications close to surface water bodies:
1- non-treated buffer zone along a water body
2- Use of a particular sprayer
3- Use of spray-drift reducing nozzles
4- Use of shields or hedges on parcels close to surface water
The width of a buffer zone (2,5,10,20,30 m) and the percentage of the percentage of spray reduction (50, 75, 90%) to be achieved are noted on the product label.
A list of material to reduce spray drift ca be found under "List of spray drift reducing nozzles"
The user can reduce the buffer zone indicated on the label, provided it has the appropriate material (low-drift nozzles etc.) and risk mitigation measures in place (hedges, shields, etc.). The table below depicts these possibilities to reduce buffer zone width (source).
End of boom nozzles provide a very short range drift reduction. Their use is recommended to reduce contamination risks of nearby cultures and non-treated zones.
Use of hedges around orchards and hop
Farmers can used hedges to protect surface water from spray drift. Hedges are considered to be part of the cultivated parcel:
- It must be composed of leafy trees (no conifers)
- it must be at least as high as the fruit trees or hop
- It must border the entire side of the parcel close to the water body
- It must not have holes
- leaves must be present on the entire length
- The distance between the hedge and the water body must take into account local legislation. Usually, it is placed at least 5 m from the surface water body
- alternatively, "walls" with reed or palox can be used