Get tips for good practices in your farm management
Regardless of whether you reside in a rural area or in a town or city, you can do your bit to safeguard Otago’s water bodies. For urban residents, you can help prevent contaminants such as soil from construction and development activities, litter, and food waste from entering the stormwater network and ultimately reaching natural water bodies.
If you are a farmer or rural land user, you can mitigate soil, nutrient and microbial losses to water bodies by adopting good management practices (GMPs). Common GMPs include strategic grazing, nutrient budgets and establishing well-vegetated buffer zones next to water bodies.
Our Catchment Advisors are dedicated to supporting Otago landowners, catchment groups and community organisations through on-the-ground programmes that enhance catchment outcomes. Catchment Advisors work towards improving water quality, biodiversity (flora and fauna) and land management practices.
Each Advisor is responsible for one or two of Otago’s Freshwater Management Unit (FMU) or rohe (area). If you want to discuss methods to assess and improve water quality, you can contact us by:
- emailing catchments@orc.govt.nz to arrange a site meeting with your local Catchment Advisor
- attending one of our events, such as Intensive Winter Grazing workshops and Stormwater Community Days – keep an eye on ORC’s Events page.
Riparian zones are the land margin beside a creek, river, lake or wetland. Planting native grasses, sedges, flaxes, shrubs and/or trees in riparian zones can improve the health of Otago’s waterways by filtering contaminants, providing shade and enhancing native biodiversity.
You can also refer to NIWA’s Riparian Buffer Design Guide to help optimise the function and form of riparian planting zones.
It can take about three years for native restoration plants to become established and shade out nearby weeds and long grass. This will of course be dependent on climate, weather patterns and various plant growth rates.
After three years, plants need less maintenance, but you should still check occasionally for climbing weeds, willow, and gorse invasion.
The number of maintenance visits required each year will be dependent on weather patterns (particularly seasonal rainfall) and growing conditions. You should expect to conduct maintenance at least twice during the main growing season (spring to autumn).
For smaller sites, hand releasing (cutting and pulling back long grass and weeds) may be a practical option. Clear the weeds and long grass around young plants and inside guards before they are smothered.
Spread the cleared/cut weeds around the base of the seedling as a mulch. Sturdy gloves and a hand cutter can help. Here’s a good example of a hand cutter: Sharks against weeds
These can be quick and effective as the weeds are left to decompose and create an organic matter layer which holds moisture and improves soil quality over time. Simply cut the grass surrounding the plant guard back about 30-40 cm, taking care not to hit the plant or guard.
Spraying herbicide around the guards means that maintenance visits can be left longer and can be particularly effective on large sites. However, native trees and grasses are very susceptible to broad spectrum herbicides such as glyphosate.
If you choose to use sprays to control grass and weed growth, first contact your chemical supplier or rural services store for advice on appropriate herbicides and methods.
When spraying near water bodies (rivers, ponds, wetlands), take care not to allow spray or spray drift to make contact with water. Many herbicides are toxic to some aquatic life.
Aim to minimise the area sprayed in riparian areas to ensure vegetative cover maintains soil stability. Exposing large areas of soil where there can be flooding can encourage erosion and slips.
Please keep in mind that herbicide spray-drift from nearby paddocks (that are being developed or resown) also has the potential to impact restoration planting survival.
Remember to:
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Follow the manufacturer's instructions and application rates carefully, including adding recommended surfactants (these often improve effectiveness)
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Aim for 0.5 metres of killed vegetation around each seedling
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Spray in a S-shaped pattern to avoid overlap i.e. along one row then the opposite way along the next row (spraying in a spiral pattern concentrates the spray)
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Take care that the chemicals do not go onto the desirable plant(s)
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Spray out from the plant/guard, not towards, to reduce the chance of spray on the plant
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Use a nozzle with a narrow fan of spray
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Consider a guard around the nozzle to protect your plant from spray. These can be bought or made at home using an old funnel or plastic bottle
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Spray on a still day to prevent spray drift coming in contact with yourself or other plants; and
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Spray grass while it is shorter, before it becomes long and rank, but while actively growing.
Please conduct regular checks of your plants during hot and dry conditions. If they begin to show signs of stress (wilting or browning) undertake watering efforts (as much as is practical).
Watering is best done thoroughly in the morning or evening, but not often (once a week).
If at any stage you become concerned about plant condition, please contact your catchment advisor.
Please check the fences and gates surrounding your planting area regularly, especially after flood events.
Some plants may not survive the first few years. Consider adding plants to fill any gaps.
You can also add in diversity once your initial plantings are established.
Some successional species (larger trees) require the shelter of coloniser species (native grasses and shrubs) to survive and are better planted later in your project.
An inspection of pest infestations should be carried out before planting.
If significant pest sign is evident, seek professional advice regarding suitable pest control options prior to planting.
When checking your plants, keep an eye out for pest animal signs. Possums, rabbits, and hares can target restoration plantings. Rabbits browse plants, whereas hares can nip the stems off.
Remember that rabbits are a ‘sustained control’ pest under Otago’s Regional Pest Management Plan and all landowners are required to control feral rabbits on their land – for more detail on the rules and control methods, see our rabbit Pest Hub page.
You may also live in an area where there are larger pests including feral deer and pigs.
Ongoing pest control maybe necessary to maintain pest levels. Regular night shooting and trapping near planting sites help to keep in check.
Chemical ringbarking using a weed-gel or paste has been shown to be successful on willow saplings and small trees (contact your chemical supplier for advice on appropriate herbicides and methods).
There is also the option of drilling holes in the base of large trees and filling with a chemical herbicide.
This allows the tree to die standing and provides a perch for native birds that can bring in surrounding native seed.
If the tree is too big or there is a large infestation, tank or aerial spray can be the most practical way to control willows (of course taking care there’s no spray drift near plantings).
Mechanical removal of riparian willows (e.g., by using diggers) may require a resource consent – see here for more information.
Cut and paste using a weed gel/paste. Large infestation can be sprayed with a knapsack or spray tank (of course being careful there’s no spray drift near plantings).
In some sites larger woody natives can be planted amongst gorse (which acts as a good nursery plant).
Over time the natives shade-out the gorse.
If you’d like to set up a native nursery, you can download this handy DIY nursery guide produced by Otago South River Care.
A regular Stream Health Check can help you understand the impacts of land use on your local waterways. The check looks at water clarity, bed sediment, levels of weed and algae cover and stream organisms that are all impacted by local land use, soils and climate. If you would like to know more, or arrange a Stream Health check for your property, please email our catchments team.
If you want to a take a water quality sample to send to a private laboratory, this video, shows how to carry out the sampling.
Working with your farming neighbours means you can learn from each other and share results. Otago has many catchment groups, and some have set up a system for water testing and stream health checks. You could join a group or establish one if your area needs it. Give one of our Catchment Advisors a call on 0800 474 082 (or email catchments@orc.govt.nz) to find out more.
Poor management of livestock winter grazing on annual forage crops can degrade water quality and ecosystem health. Intensively winter-grazed paddocks increase the risk of sediment runoff into waterways. When animals feed on annual forage crops, their trampling can result in paddocks becoming pugged, damaging soil structure and stripping land of its protective vegetative cover. This results in the increased discharge of nutrients, sediment and microbial pathogens into surface and ground water.
IWG Videos
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Watch ORC’s IWG video here
IWG Management plan
This plan explains environmental good practice and can help you document the grazing management of winter crop paddocks. A Catchment Advisor can help you complete it.
Note: This is not a regulatory document, but you can use it or other templates help you manage your winter grazing. You should also check if you need to apply for an intensive winter grazing resource consent by clicking here.
Great work is being done to promote good management practices for intensive winter grazing. Here are some useful industry agency links:
Here are some winter grazing tips (adapted from Beef+Lamb NZ):
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Exclude stock from waterways. Create an ungrazed buffer zone between the stock and the waterway. Five metres is a good starting point, but this should increase with slope and soil instability.
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Leave an ungrazed and uncultivated buffer zone around Critical Source Areas. Critical Source Areas (CSAs) are parts of the paddock that can channel overland flow directly to waterways (e.g. gullies, swales, very wet areas, spring heads, waterway crossings, stock camps and vehicle access routes). Read the Critical Source Areas fact sheet here.
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Graze paddocks strategically. Fence sloping paddocks across the slope and start grazing at the top of the slope i.e. graze from top of the slope to the bottom. That way, the standing crop acts as a filter. Or, if there is a waterway in the paddock, start grazing at the far end of the paddock.
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Create a written paddock plan. Include a paddock map marking waterways, CSAs, fences and grazing direction.
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Make breaks “long and narrow”, where possible. The crop will be utilised more efficiently by stock. (Note: Deer might need alternative grazing management.)
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Back fence, where appropriate. Back fence stock, help to minimise pugging damage and reduce run-off risk. (Note: This is not always appropriate and Deer might need alternative grazing management.)
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Place portable troughs and supplementary feed in a dry part of the paddock well away from any waterways or CSAs.
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Look after your stock. Providing adequate feed, shelter, lying areas and clean fresh drinking water will limit stock movement and help reduce damage to crop and soil.
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Plant a catch crop. Where soil conditions and farm management allow, consider planting a fast-growing crop in spring such as greenfeed oats, to utilise excess nutrients. It can make a substantial difference to reducing nitrogen losses.
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Plan early. When choosing paddocks for next year’s winter feed crop, think about how you can improve your management of CSAs and waterways. Consider leaving CSA’s uncropped and in permanent pasture.
