Using Vegetation as a buffer to reduce spray drift

What is a Vegetative Barrier or Buffer Belt?.
A row or rows of trees, shrubs or tall grasses planted to reduce the spray drift of agricultural chemicals by filtering out spray droplets in air passing through foliage.

Trees act as a buffer belt beside these vines

A tall row of rye corn planted along the sprinkler row is a suitable buffer beside this lettuce crop

Why plant a Buffer Belt?.
Plant buffers to reduce spray drift. A good buffer belt works by allowing air to pass through foliage while filtering out spray particles and reducing possible damage to human health, the environment, crops and livestock.

Percentage down-wind drift of a pesticide (trial conducted February 1997 using a eucalypt/wattle buffer)

Other benefits of buffer belts include productivity gains from improved crop and livestock shelter, filtered noise and dust levels, reduced complaints from concerned neighbours, lowered water tables, habitat for wild life and increased aesthetic values.

Sweet Corn intercropped with vegetables forms an effective buffer

What to plant.

Trees:

• Casuarina or she-oaks are ideal species.

Shrubs:

• Tea-tree, eg: leptospermum, melaleuca.
• Banksia.

Tall Grasses:
for low growing crops only

• Rye corn.
• Sorghum.

Where to plant.

• On crop boundaries.
• Next to sensitive areas.
• Between blocks or paddocks.
• Along sprinkler rows (low growing crops only).

Effective Buffer Belts.

A good buffer belt should be:

• Semi-permeable - you should just be able to see through it. This allows air to pass through foliage, filtering out spray particles and dust.
• At least 50% taller than the target plant.
• Located in consideration of sunlight and prevailing wind direction.
• Multi-rowed if possible.
• Made up of species with long, thin, rough foliage, eg: casuarina.

Avoid solid barriers which force spray to be pushed up and over the barrier and drift further.

Limitations of Buffers:

Be aware of the limitations of buffers:

• They are not a substitute for good spray management practice. See "Code of Good Practice for Farm Chemical Spray Application", available from DNRE.
• Buffer belts WILL NOT stop vapour drift or odour.