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Critical source areas

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Buffers

Critical Source Areas (CSAs), such as swales and gullies, can transport large amounts of soil, phosphorus, and E. coli to waterways. Recognising CSAs and managing them with buffer zones can help minimise these losses. Leaving grass buffers slows water flow, allowing it to soak into the soil rather than run off. You might need larger buffers if your paddock has certain conditions like steep slope, heavy rainfall, or high stock density. Always check with your Regional Council for any regulations and create your winter grazing plan accordingly.


Identifying Critical Source Areas (CSAs) and then managing them using buffer zones can significantly reduce losses to surface and groundwater.

Critical Source Areas (CSAs) are parts of the landscape, such as swales and gullies, where overland flow and seepage converge to form small channels of running water, which may then flow to streams and rivers. CSAs can transport large amounts of soil, phosphorus and E. coli to waterways.

Before you start your planning, ensure you are aware of any regulations that your Regional Council may have and the national wintering regulations.

Buffers

Leaving grass buffer strips will provide a filter and slow down water movement, allowing it time to soak into the soil rather than running off.

In situations where a buffer is filtering a large amount of runoff, or it is fast flowing, a larger buffer is required. This includes situations where the crop paddock has a:

  • heavy or weakly structured soil
  • steeper slope
  • higher rainfall
  • higher stock density

Once you have identified your paddock and CSA’s its time to complete your winter grazing plan.

Farmer tip:

“My farm is relatively flat. Each winter, after some heavy rain, I look at the paddocks I am hoping to crop next year. I mark out the CSAs then with fence standards because sometimes they are harder to see in Spring.”

Critical source area cultivated, resulting in higher risk of soil, E. coli and phosphorus loss.

 

 

Critical source area cultivated and unprotected, resulting in higher risk of soil, E. coli and phosphorus loss.

 

 

Critical source area has been given a large buffer and both CSA and buffer zone left uncultivated.

Critical source area left uncultivated and ungrazed.


Once you have identified your paddock and CSA’s its time to complete your winter grazing plan.

Last updated: Sep 2023
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