We know that intensive grazing is an essential element of many Otago farming systems, but when it’s not managed well it can result in significant nutrient and sediment losses into waterways that may impact water quality.
If you need to practice intensive winter grazing (IWG), it’s important to plan ahead, ensure your approach meets the national legal requirements and follow the relevant rules for our region.
Intensive winter grazing refers to the grazing of annual forage crops between 1 May and 30 September of the same year and is subject to restrictions under the National Environmental Standards for Freshwater (NES-F).
The practice of intensive winter grazing, particularly in wet conditions, can lead to significant soil damage, which can result in large amounts of sediment, faecal pathogens and nutrients being discharged into watercourses from runoff during heavy rainfall.
The risk of soil damage and contaminant discharge increases as the slope of the land increases, and where there is increased connectivity to nearby surface water.
Changes to the NES-F took effect on 25 October 2024 Central government repealed the permitted and restricted discretionary activity regulations for intensive winter grazing in the NES-F, replacing them with standalone regulations on riparian setback (planted river margins) and critical source areas (areas like gullies and swales that can accumulate and convey water and contaminants to waterways).
- Livestock must be kept at least 5m away from any from the bed of any river, lake, wetland or drain, regardless of whether there is water in it at the time.
- Critical source areas within the area used for IWG must be maintained in vegetation and must not be cultivated. Forage crops must not be harvested and the land must not be grazed.
The following two rules under the Otago Water Plan are also relevant to intensive winter grazing:
- Any discharge from land that has been disturbed by stock, where sediment reaches a water body or the Coastal Marine Area, that doesn’t have a sediment mitigation is prohibited. (RPW 12.C.0.3)
- The discharge of sediment that results in an increase to the local sedimentation or has a conspicuous change of colour or clarity in a river, lake or wetland is not permitted. (RPW 12.C.1.1)
This information will be reviewed regularly to check for any changes required as a result of new national requirements. For more information, please refer to the Ministry for the Environment website.
A well-managed intensive winter grazing activity means:
- Avoiding critical source areas, such as wet spots in paddocks, gullies and swales
- Leaving a grassed or planted buffer strip between the area of grazing and any critical source area or water body
- Break feeding from the top to the bottom of a sloped paddock
Refer to your farming industry organisation for more guidance, as they’ll be able to assist with solutions specific to your farming operation.
Good preparation is crucial for managing your intensive winter grazing well. It’s best to start thinking about how you will manage your grazing well before selecting paddocks and beginning cultivation. The winter grazing plan template could help.
Understanding the impacts of sheep winter grazing
June 2023
PDF | 982 KB
This three-year research project sought to understand the significance of contaminant losses and the effectiveness of good management practices for sheep winter grazing to enable farmers to make evidence-based land management decisions.
Annual forage crops are crops grazed in the place where they are grown, including cereals (such as sorghum, barley, oats, ryecorn and triticale), brassicas (such as kale, turnips and swedes) and fodder beet.
If you are growing cereals, brassicas or fodder beet for grazing by stock during winter, it is a forage crop.
If the mix is more pasture than it is fodder crop, then it will be treated as pasture. For example, if it is 80% pasture and 20% fodder then it will not be treated as an annual forage crop. However, if it is 60% fodder and 40% pasture then it will be treated as an annual forage crop.
No, annual ryegrass is not considered an annual forage crop.
If you manage your cereal crops in a way that means that after grazing the crop re-grows and is harvested or grazed again without re-sowing, they will not be considered annual forage crops.
Rule 26(4)(b), National Environmental Standards for Freshwater: The slope of any land under an annual forage crop that is used for intensive winter grazing must be 10 degrees or less, determined by measuring the slope over any 20m distance of the land.
No, the less than 10 degrees requirement only applies to the area planted in annual forage crop. The slope must be less than 10 degrees in the steepest area of the cropped area, measured over 20m.
You may also want to consider Good Management Practices to avoid sediment loss in areas less than ten degrees slope and include these actions in your
Winter Grazing Plan.
See Beef + Lamb, DairyNZ, and Ministry for Primary Industries websites for winter grazing plan resources:
One method of measuring slope is to put two standards approximately 20m apart and then measure from the top of one peg to the top of the other using a clinometer or slope measurement app or tool.
The video below explains how to measure slope in your winter grazing paddocks.
Slope is measured between two points in a paddock 20 m apart, rather than on each hump and hollow.
To be a permitted activity, the slope of any land under an annual forage crop that is used for intensive winter grazing must be 10 degrees or less, determined by measuring the slope over any 20 m distance of the land. Council will use a clinometer or a mobile phone app or tool. Council may also use drones, aircraft and high-resolution digital elevation maps available in some areas.
Rule 26(4)(d), National Environmental Standards for Freshwater: livestock must be kept at least 5 m away from the bed of any river, lake, wetland, or drain (regardless of whether there is any water in it at the time)
You must have a buffer of at least 5m from areas of grazed forage crop and rivers, lakes, wetlands or drains. This buffer is regardless of whether they contain water or not. A 5m buffer is the minimum legal requirement and if your buffers are smaller than this you will need resource consent.
You may also want to consider wider buffers as good practice. The good practice rule of thumb is, the steeper the slope, the wider the buffer should be.
The 5m buffer must be measured from the edge of the bed for rivers and lakes. This is measured from where the river reaches its fullest flow without overtopping its banks. The aim is to avoid winter grazing in wet areas. If in doubt, be conservative and put in wider buffers and keep stock out of these areas.
A wetland includes permanently or intermittently wet areas, shallow water, and land water margins that support a natural ecosystem of plants and animals that are adapted to wet conditions. Identification of whether an area is a wetland may require expert advice from an ecologist.
Sub-surface drains are exempt from the buffer requirement (no buffer required).
Rule 26A(1), National Environmental Standards for Freshwater: A person using land on a farm for intensive winter grazing in accordance with regulation 26 must take all reasonably practicable steps to minimise adverse effects on freshwater of any pugging that occurs on that land.
Pugging can result in loss of sediment and other contaminants to water bodies during rainfall events. Areas at greater risk of pugging and loss of contaminants to water bodies are:
- Paddocks with Critical Source Areas (see FAQs on Critical Source Areas above) where surface water flow can enter water bodies
- Paddocks with steep slopes and/or poorly drained soils
- Areas around gates and water troughs.
Consider the following actions to help you minimise effects on freshwater:
- Careful paddock selection,
- Careful paddock preparation and using reduced or no till cultivation such as direct drilling where appropriate, to retain soil structure and improve soil resilience.
- Management of stock during grazing. For example, ensure stock begin grazing the least risky parts of the paddock first to minimise the period of runoff risk. This usually means that stock should enter at the top of paddock catchments/gullies and graze their way downhill.
- Strategic grazing principles such as directional grazing and backfencing
- Placement of water troughs and supplementary feed in areas less prone to pugging and away from waterways
- Use of grass strips within paddock to trap sediment
- Where appropriate leave some vegetated cover to help protect soils
- Having a plan B for adverse weather events, for example avoiding using higher-risk areas during these times.
- Ensuring there are appropriately sized vegetated buffers, ideally grassed.
- As a rule of thumb, the steeper the slope the wider the buffer should be.
- Avoiding grazing Critical Source Areas (see Critical Source Area FAQs)
- Using sediment traps or placing hay bales at the bottom of Critical Source Areas to trap sediment.
Plan and implement actions using a Winter Grazing Plan to show you have taken all reasonably practicable steps to minimise adverse effects from pugging on freshwater:
It is always better to talk to your regional council early if things go wrong – so please pick up the phone or email us Your farm advisor, DairyNZ and Beef + Lamb extension staff can also provide support and resources.
Rule 26B, National Environmental Standards for Freshwater: A person using land on a farm for intensive winter grazing in accordance with regulation 26 must ensure that vegetation is established as ground cover over the whole area of that land as soon as practicable after livestock have finished grazing the land.
The term ‘as soon as practicable’ is not defined in the rules. However, you can use your Winter Grazing Plan to demonstrate to Councils you have re-sown paddocks used for intensive winter grazing as soon as practicable.
Councils will want to see the following in your Winter Grazing Plan:
- Your planned re-sowing date.
- Any factors that may delay this re-sowing date, such as paddocks are too wet, contractors are not available, bad weather is forecast.
- Actions you will take to minimise loss of sediment during any delay periods. For example, placing haybales in swales and leaving rank grass
buffers in place.
You need to have used land on the farm for intensive winter grazing from 1 July 2014 to 30 June 2019. It does not have to be the same paddock. You must not have increased the size of the area used for intensive winter grazing in any one winter between 1 July 2014 to 30 June 2019.
If you are unsure about the rules, please check with us.
Rule 29, National Environmental Standards for Freshwater: The conditions are that—
- land on the farm must have been used for intensive winter grazing in the reference period; and
- at all times, the area of the farm that is used for intensive winter grazing must be no greater than the maximum area of the farm that was used for intensive winter grazing in the reference period.
