Winter grazing
Winter grazing on forage crops is an important part of many farm systems, as it allows farmers to meet the energy requirements of animals during the colder months when grass is not actively growing.
In Waitaha Canterbury, we want to ensure farmers are undertaking good winter grazing practices to help protect the environment. It also makes sense to protect your precious assets on-farm – such as soil, nutrients, water quality and the health of your stock.
Undertaking good wintering practices can help you:
- reduce soil and nutrient loss and prevent contaminant loss to waterways
- support animal health and welfare
- remain agile in periods of wet or adverse weather
- meet environmental and animal welfare regulations
- improve farm team communication
- support cost-effective decision-making on farm
- maintain social licence to farm and safeguard the reputation of primary industry producers.
Mitigating environmental risk
The cold and wet conditions during the winter grazing period coupled with high animal density in smaller areas (e.g. animals behind a temporary winter crop break fence) can impact the environment and the health of our waterways.
The deposition of dung and urine by animals, coupled with wet, muddy conditions, lack of ground cover and animal movement (causing pugging and compaction) can increase surface runoff made up of contaminants like phosphorus, nitrate, sediment and faecal microorganisms.
Critical source areas
This runoff can enter our waterways through critical source areas (CSAs), negatively impacting water quality and ecosystems. Nitrates from animal urine are mainly lost via drainage, but can still be lost via surface runoff.
Under winter grazing, common natural landscape features like gullies, swales, or depressions act as overland flow paths, accumulating runoff from surrounding land and carrying it to waterbodies. These are known as critical source areas or CSAs.
Managing critical source areas
It’s important to identify and manage your CSAs, particularly those located on rolling and undulating land.
CSAs can be ephemeral waterways, which means they do not contain water year-round, but are active during or immediately after heavy rainfall events. Multiple runoff areas can converge into ephemeral waterways, and natural springs can also act as critical source areas – so if in doubt, keep stock out with temporary or permanent fencing.
Other areas on your farm can also be considered CSAs, including areas of high foot traffic such as:
- laneways
- stock races
- yards
- feeding or trough areas
- gateways
- camping sites.
Be mindful of how winter grazing activities may impact on these areas to ensure runoff is not exacerbated.
More information on understanding and managing CSAs during winter grazing can be found at Ministry for the Environment or at DairyNZ.
Managing nitrate leaching
The risk of nitrate leaching is higher during the cooler and wetter months of the year when winter grazing takes place. Intensive grazing situations can result in high nitrogen losses from animal urine patches.
This nitrogen is then converted to nitrate in the soil through a natural process and is lost to groundwater through leaching.
Integrating catch crops after forage crop grazing can help mitigate losses by ‘mopping up’ the excess nitrogen in soils, which may otherwise be lost through leaching as nitrate.
Catch crops can also increase annual dry matter production and aid soil restoration.
Find out more in the ‘Catch crops for reduced nitrate leaching’ joint research on our reducing nitrogen loss page.
Good management practices for winter grazing
Here are some ways to protect soil structure and reduce the leaching of nitrogen and phosphorus into waterways on your farm:
- Paddock selection for winter is crucial – it's best to choose paddocks away from waterways and wet areas prone to pugging to reduce the risk of sediment and nutrient run-off.
- What's your plan for bad weather? Having practical bad weather mitigations must be part of planning your winter feed management. For example, what will you do to stop soil damage and increased run-off entering waterways during storm events?
- When planting the crop, leave grass buffer strips around critical source areas, such as gullies and swales, where the run-off collects and flows out of the paddock.
- Have a good look at the landscape and ensure there are larger buffers around the waterways. This can really help reduce sediment and nutrient loss into waterways.
- Leave critical source areas in pasture. If they need to be grazed, do it after the winter grazing season when soil conditions are dry and there is no risk of runoff to waterbodies
- It's also a good idea to back-fence stock off the land that has already been grazed, to even further reduce run-off. Strategic grazing and careful management of critical source areas can reduce losses of sediment and phosphorus (P) by 80–90 per cent.
- In wet conditions, practice on/off grazing to minimise pugging damage to the soil and distribute nutrients from dung and urine more widely.
- Plant a cool tolerant follow-up crop, such as oats or rye, as soon as possible after grazing. This can soak up nutrients from the soil, rather than them being leached if the paddock is left fallow.
Winter grazing planning resources
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Spring factsheet (PDF file, 10.49MB) – Plan early in spring to set up paddocks, manage risks, and protect soil and waterways
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Pre-winter grazing factsheet (PDF file, 5.74MB) – Key steps before grazing begins, including managing runoff, identifying critical source areas, and meeting requirements.
Regulations for winter grazing
Winter grazing is managed through national and regional rules that protect waterways, soil, and farm systems. The sections below outline what applies, so you can quickly understand your responsibilities and plan compliant winter grazing on your farm.
National regulations
The National Environmental Standards for Freshwater include regulations for managing intensive winter grazing across New Zealand. As of October 2024, the two national regulations are:
- Five metre setback – intensive winter grazing needs to be located at least five meters away from any river, lake, wetland, or drain (regardless of whether there is any water in it at the time).
- Protect Critical Source Areas – CSAs that are within, or adjacent to, intensive winter grazing paddocks need to be ungrazed, vegetated, with no cultivation or harvesting of annual forage crops.
In the national context:
- Intensive winter grazing means ‘grazing livestock on an annual forage crop between 1 May and 30 September of the same year’. Note that this definition includes all livestock.
- Annual forage crops are crops grazed in the place that they are grown, but this doesn’t include pasture or crops for arable or horticulture purposes. Annual ryegrass is a pasture, so isn’t considered an annual forage crop.
Regional rules
In addition to the national regulations, the Canterbury Land and Water Regional Plan (LWRP) has rules that don’t directly manage winter grazing, but need to be considered when undertaking winter grazing on your farm.
In the context of the LWRP:
- Winter grazing means the grazing of cattle within the period of 1 May to 30 September, where the cattle are contained for break-feeding:
- of in-situ brassica and root vegetable forage crops (this does not include non-brassica or non-root crops such as oats or other multi-species mixes); or
- for consuming supplementary feed that has been brought onto the property.
In some sub-regional areas, the Farming Land use (FLU) rules also include deer that are winter grazing.
Stock exclusion rules
Any cattle and deer winter grazing will automatically need a resource consent to:
- access the bed of a lake, river or wetland
- some springs or artificial water courses.
Cattle and deer may be totally prohibited from having access to sensitive areas, such as salmon spawning sites or a Mātaitai and Waipuna Protection Zone.
More information on stock exclusion rules for specific zones can be found on our stock exclusion page
Direct discharges of contaminants into surface water rules
Rules exist in the Canterbury LWRP for discharging contaminants directly to surface water. For winter grazing, this can include runoff (e.g. water, dung, urine, sediment) from winter grazing paddocks into water bodies.
There are also restrictions on the effects from any discharge on water quality, for example, meeting standards for suspended solids, E.coli and visual clarity. See rule 5.99 and Schedule 5 in the LWRP.
Nutrient management and farming land use rules
There are a series of rules across Canterbury that manage nutrient losses from farms as a whole, rather than splitting them up into separate activities like winter grazing or effluent discharge. These rules can differ depending on the type, size and location of your property and may need consideration as part of winter grazing planning on farm.
Within these rules, the Canterbury LWRP includes thresholds for winter grazing that, depending on other requirements, may act as a trigger for farming land use (FLU) consents. This threshold does not necessarily limit the amount of winter grazing a farm can have, but it can mean that a FLU consent is required.
If your farming operation meets all rule requirements you can operate under permitted activity rules and do not need a FLU consent.
For more information on FLU consent requirements, visit our Farming Land Use consent webpage to check the specific rules for your farm’s sub-region.
Farm Environment Plans (FEPs) and audits – if you have a FEP as part of a FLU consent or as a requirement for being a member of a wider collective or irrigation scheme, you’ll need to provide evidence for your FEP audit showing how you are implementing good management practices related to winter grazing. This will include your winter grazing management plan. Learn more about Farm Environment Plans.
Winter grazing flights
During the late autumn and winter period, we may conduct one or more flyovers in a fixed-wing light aircraft to observe how farmers are setting up their wintering paddocks.
This helps ensure appropriate management practices are being implemented to mitigate any adverse effects on the environment. Staff from our Water and Land team are accompanied by industry representatives during these flights.
The fly-over is for observational and educational purposes only, as explained in our article about winter grazing in practice.
Make sure you have a winter grazing plan in place
A good plan identifies the environmental risks associated with the activity and how you plan to manage and mitigate each of these risks, including reducing nutrient and sediment run-off and improving soil productivity.
Your winter grazing plan will be the key reference that you and your staff follow over the winter months, and have a Plan B (alternative plan) ready in case of extended wet weather events.
Government and industry organisations have developed several winter grazing management templates and guidance documents you can use to make your plan:
Our compliance approach
Environmental effects from winter grazing can be high risk. National regulations and the rules in our Land and Water Regional Plan restrict stock access to waterways and discharge to water.
Our compliance monitoring and enforcement team ensure that intensive winter grazing and other land uses do not create unnecessary risks to our land, air and water, and follow up on any incidents where they do. Incidents will be assessed on their merits, and compliance action may be taken where necessary.
Where to find more information
Our land management advisor team are here to help guide you on winter grazing best practice. If you have any questions, email us at winter.grazing@ecan.govt.nz and we’ll get back to you with advice. Otherwise, you can get in touch with your local land management advisor for support via our Advisory Team on 0800 324 636 or ecinfo@ecan.govt.nz.