20 September 2024

Minimum buffers to protect water

Crops Specialist at Teagasc, Ciaran Collins looks at the role buffer zones along watercourses play to help prevent sediment, nutrient loss and pesticides entering watercourses – a key feature of the Teagasc tillage display at this year’s National Ploughing Championships.

A buffer zone is an area of land adjacent to a water feature in which certain agricultural activities are prohibited. The width of a buffer zone varies depending on the activity taking place in the field. Some of the key buffer zones that relate to tillage are outlined in figure 1 below.

Figure 1: Minimum buffer zones to protect water

Table 1: Minimum buffers to protect water

Activity	Minimum Buffer (m)
Organic fertiliser	5
Organic fertiliser where slope towards watercourse exceeds 10%	10
Organic fertiliser buffer increases to 10m for the 2 weeks before and after the prohibited period	10
Chemical fertiliser	3
Uncultivated margin for non-grass crops	3
Intersecting watercourse – late-harvested crops	6
Grass/vegetated – forage grazed in situ	4
Plant protection products	3

For late-harvested crops, a minimum uncultivated buffer of 6m shall be put in place to protect any intersecting watercourses. A ‘late-harvested crop’ includes vegetable crops harvested after 15^th September as well as fodder beet, sugar beet, main crop potatoes and maize excluding cereal crops and beans.

An ‘intersecting watercourse’ means where a land parcel is sloped towards a watercourse and any surface water run-off would drain into that watercourse. In figure 1 above, the slope of the field is towards the river at the bottom (intersecting watercourse), therefore the buffer increases from 3m to 6m.

For plant protection products (PPPs), a minimum 3m no spray buffer zone applies to all watercourses, but a PPP authorisation may prescribe a buffer zone which is greater than 3m. A PPP buffer zone can be reduced by the use of drift reducing nozzles, but cannot be reduced further than 3m.