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.
Regulations for winter grazing
Intensive winter grazing (IWG) is defined as grazing livestock (including sheep) on an annual forage crop at any time in the period that begins on 1 May and ends on 30 September of the same year. An annual forage crop is a crop, other than pasture, that is grazed in the place where it is grown. Annual ryegrass is a pasture, so isn’t considered an annual forage crop.
National regulations
In October 2024, updates were made to the national winter grazing regulations. Changes to the Resource Management Act have:
- removed the need for a resource consent for intensive winter grazing where default permitted conditions were not met e.g. for total area or where an increase in area was proposed
- removed the national slope restriction for winter grazing activities and stand-alone regulations relating to pugging and ground cover.
The Act introduced new regulations requiring:
- land used for intensive winter grazing to be located at least five metres away from any river, lake, wetland, or drain (regardless of whether there is any water in them at the time)
- the protection of critical source areas in relation to land that is used for intensive winter grazing.
While the national rules have changed, the regional rules (outlined below) are still applicable and may vary depending on your farm location (sub-region).
Regional rules
In addition to the national rules, our Land and Water Regional Plan (LWRP) contains permitted activity rules for winter grazing from 1 May - 30 September in the same year. If you are unable to meet these rules, a resource consent for farming land use is required.
In most parts of Waitaha, you will require Farming Land Use consent if you have an area of winter grazing:
| on a property | winter grazing area |
| less than 100ha | 10ha or more |
| between 100ha and 1000ha | 10 percent of the property or more |
| more than 1000ha | 100ha or more |
However, some areas have additional protections and different consent triggers. Visit our Farming Land Use consent webpage to check the specific rules for your farm’s sub-region.
Late season critical source area management
We’ve had some questions from the community around managing the ‘last bite’, which refers to grazing the pasture that protects a waterway or critical source area once the crop has been eaten.
To minimise risks to waterbodies, the national rules state that Critical Source Areas adjacent to or within winter grazing areas must not be grazed at any time through to 30 September.
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.