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Farmer tips Winter crop cultivation Critical source areas

Winter crop cultivation is crucial to your dairy farm's success. Be sure to have a detailed plan that includes aspects like paddock slope, critical source areas (CSAs), and buffer zones. Follow the national intensive winter grazing rules to protect both the environment and animals. Remember, cultivating across slopes and leaving grass buffers at their bottom reduces soil runoff and sediment loss. The latest research shows no till cultivation yields great results. For paddocks on a steep slope, consider other suitable options for winter cropping. Discuss your plan with your contractor before you start for smooth operation.

Cultivation of winter crops is an essential part of setting up for a successful winter. Ensuring paddocks are cultivated with agreed management strategies in place will reduce the risk to animals and the environment.

National Intensive winter grazing rules are now in place and regulations around the cultivation of critical source areas are now in place. See Intensive winter grazing rules for detailed information.

Having a detailed cultivation plan for every paddock will help you meet wintering requirements. Plans should include any critical source areas to avoid, waterways, paddock slope, buffers, and the required width of the buffer.

Farmer tip:

"We put up a semi-permanent fence around CSAs before the paddock is cultivated. This guarantees that it is not cultivated or grazed."

  • Cultivate across slopes rather than up and down. If the paddock is too steep to cultivate across the slope it is likely that it is not suitable for winter cropping.
  • Consider which cultivation type you will use. In recent research no till cultivation has been shown to deliver good yields and improved crop utilisation rates during grazing.
  • Leave grass buffers at the bottom of slopes. This will filter and slow down runoff from the paddock, reducing the amount of sediment lost from the paddock.

Farmer tip:

"I have to be clear on the direction I want the paddock cultivated. I want the contractors to cultivate across the slope to avoid soil getting washed out in heavy rain."

Ensure your contractor has all the information required before you start. Sharing detailed cultivation plans with your contractor before cultivation begins will put your mind at ease and prevent any future complications.

Critical source areas can occur in all parts of the farm, even if relatively flat.

An unsprayed, uncultivated grass buffer.

As a contractor, you are an essential part of setting up farms for successful wintering. Working with your farmer clients to ensure paddocks are cultivated with management strategies in place will reduce the risk to animals and environment.

Intensive wintering grazing rules are in force from 1 Nov 2022. We encourage contractors and farmers to become familiar with the updated rules before cultivation starts.

For the most up-to-date information see Intensive winter grazing rules

You can protect your business and your reputation by ensuring you have all the information required before you start. A conversation with your client or manager before you start cultivating a paddock will put your mind at ease and prevent any future complications.

Winter crop cultivation

Soil cultivation removes vegetation and exposes the soil to the weather, increasing the risk of soil runoff during bad weather. Nitrogen, phosphorus, soil and E. coli losses from winter forage crops are much higher than those from pasture grazed during other times of the year.

A relatively small area of winter crop can make a disproportionately large contribution to nitrogen losses from the dairy farm or grazing system. The amount of N and P lost from a crop paddock can be two to seven times as much as a pasture. Too much nitrogen, phosphorus, soil or E. coli in waterways can be toxic to aquatic life, cause human health issues, contribute to excessive plant growth, and reduce recreational and aesthetic values.

The presence of slope, critical source areas (CSAs) and waterways increase the risk of sediment, E.coli and phosphorus loss to waterways. Careful management of these areas has been shown to significantly reduce losses, and uncultivated buffers around waterways act as a filter for overland flow.

Critical source areas

Critical source area means a landscape feature such as a gully, swale or depression that accumulates run-off from adjacent land and delivers, or has the potential to deliver, 1 or more contaminants to 1 or more rivers, lakes, wetlands or drains or their beds (regardless of whether there is any water in them at the time”. CSA’s left uncultivated will provide a filter and slow down water movement, allowing it time to soak into the soil rather than running off.

Buffer zones or grass strips in and around CSAs and next to waterways, act as filters by slowing the overland flow to trap suspended sediments. Buffers around waterways and CSAs (including drains) need to be left in grass and ungrazed through the whole grazing period. Buffers around critical source areas need to maintain vegetation cover until after 30 September.

Crops should only be planted on slopes that are 10° or less. If your client wishes to plant on slopes over 10° they will require a consent. This requirement is part of the new wintering regulations that are in place from 1 November 2022.

Creating an uncultivated buffer at the bottom of the slope will help to reduce the risk of sediment from winter crops entering the waterway.  Where safe, cultivate across slopes rather than up and down. Cultivating up and down can speed up the overland flow of water during heavy rainfall events.

Place bales away from waterways and CSAs. Cows will spend a lot of time around the bale which will result in greater soil damage in these areas.

The national wintering rules require a minimum of a 5m buffer around waterways, wetlands or drains (regardless of whether there is any water in it at the time). Please check with your regional council to determine if a wider buffer may be required under local regulations.

Critical source area

Critical source area terminology


A gully is a small but deep trench, typically on a hillside. It can be a sign of serious erosion of soil by running water.


A swale is a shallow channel with gently sloping sides; a low-lying part of a paddock that can be moist or marshy.

Buffer zone

Buffer zones or grass strips in and around CSAs and next to waterways act as filters by slowing the overland flow to trap suspended contaminants.

The buffer should ideally be left uncultivated to operate effectively. The faster the water is flowing into a buffer zone (ie. the greater the slope of the paddock), the wider the buffer zone will need to be to provide time for effective filtering and infiltration.

Last updated: Sep 2023

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