Waikato Peat Lakes - Hayes Family

Waikato Peat Lakes - Hayes Family

Project Details:

The Hayes instigated the Lake Kaituna and Lake Komakorau Care Group (both Department of Conservation lakes).

Location: Waikato

Property Size: 88 ha dairy farm bordering Lake Kaituna (22ha – average depth 1.3m) and Lake Komakorau (9 ha, average depth 600mm). The total size of the catchment of the two lakes is 580ha.

Main objectives/issues: Minimising nutrient runoff into rare peat lakes, restoring lake margins and wildlife habitat.

Investment: Lake Kaituna and Lake Komakorau Care group, DOC and Environment Waikato (now Waikato Regional Council), MfE’s Sustainable Management Fund.

NZLT role/involvement: Lake Kaituna and Komakorau Care Group committee member and technical advisor, coordinator for rare wetland plant re-establishment trial and sustainable land management in shallow lakes catchments projects.

What's next?

From July 1, 2019, Lake Kaituna will start to be monitored on a monthly basis thanks to an increase in lake water quality monitoring being undertaken by the Waikato Regional Council.

This monthly monitoring will include: temperature and dissolved oxygen profiles, secchi disc measurements for water clarity, water samples for water chemistry (nitrate-nitrite nitrogen, ammonium, total phosphorus, Total Kjeldahl Nitrogen, dissolved reactive phosphorus, turbidity, suspended solids, volatile suspended solids, chlorophyll a, conductivity, pH and E. coli). There will also be quarterly zooplankton samples and possibly monthly algal samples, depending on budget.

Waikato Peat Lakes - Hayes Family

Project benefits

• Improved productivity on less land.
• Reduced fertiliser costs.
• No more stock lost in boggy margins.
• Greater water retention in low paddocks during dry periods.

• Better lake water quality.
• More native plants and animals.
• Rare wetland ecosystem restored.

• Farmers and agencies working together to improve the environment.
• More attractive environment in which to work and live.
• Valuable educational facility for other farmers, schools, tertiary institutes local and overseas visitors.
• Research site for universities.

Winning Ways on the Farm

Retiring ten percent of your dairy farm for wetland conservation while keeping your stocking rate the same is a pretty impressive piece of farming. Little wonder then, that Andrew and Jenny Hayes and their four sons have received a national Green Ribbon Award, on top of a regional Ballance Farm Environment Award for their sustainable farm management practices.

Waikato Peat Lakes - Hayes Family

Sitting on Peat

The Hayes’ dairy farm lies amid a string of rare peat lakes, tucked behind a broad bend of the Waikato River in the north of Hamilton. Over the last 20,000 years these lakes, once nestled in extensive raised peat bogs, provided habitat for plants, animals and insects adapted to very low nutrient and acidic conditions. These days, most of the 33 remaining peat lakes are severely degraded – including the two bordering the Hayes’ Horsham Downs farm – Lakes Kaituna and Komakorau.

When the family realised their farming practices were contributing towards harming the water quality in the lakes, they decided to change how things were done. “If you’re aware, you care” says Andrew. He likens their new management practices as “farming to the lake”, not literally of course, but taking a landscape approach to ensure their farm works around the lakes’ needs, without losing productivity.

A farm that does no harm

Seeking to first minimise their impact on the lakes, the Hayes fenced out the stock and retired the land around the lakes, creating a wide buffer of wetland vegetation to trap silt and nutrients. Andrew didn’t want the boggy areas for summer grazing, as they only ever produced low quality and weedy feed. Fencing off those wet areas means no more bogged down stock and no nutrients wasted on feeding nothing but willows!

All drains were also fenced and managed to protect the valuable peat soils.

Modifications include:

• Keeping drains shallow and wide to reduce rates of peat shrinkage
• A grass sward on either side to trap nutrients and sediments
• Drain-side planting to shade the water and prevent nuisance aquatic weed growth
• Minimal drain clearing - mostly with herbicide rather than diggers
• Sediment traps and vegetation filters like carex and sedge beds on all drains entering the lakes, and keeping stocking rates moderate to avoid compaction and pugging.

Mind your P’s and N’s

The Hayes then started working on reducing their fertiliser rates. Annual nutrient budgets help them balance the inputs and outputs, and soil testing is carried out annually to maintain optimum nutrient levels. With areas of low productivity retired, nutrients are targeted on higher productivity areas and the savings have been huge.

• Annual nitrogen application has dropped from around 150 kg/ha, to 58kg/ha. OVERSEER leaching between 24 – 26 kg/ha per year. kg/ha.
• Super phosphate use has gone from 900 kg/ha to 650 kg/ha, and now applied in a split dressing in October and April, as long as the grass is in an active growing state, for better uptake of nutrients and less runoff.
• Nitrogen leaching is minimised through irrigating effluent over the whole farm and retaining wide margins on drains and the lake
• Effluent application depth is also monitored. These and other practical on-farm changes save the Hayes time and money – resources they now spend on restoring the lakes.

Tortured by willow

In 1999 both lakes were hidden by a thicket of invasive grey and crack willows. The dense summer canopy shaded out any undergrowth, so no runoff was trapped – but plenty of stock were, often needing a ‘block and tackle’ to haul them out. The lack of food pushed ducks out onto the paddock, competing with stock. A thousand or so chainsaw hours later, the Hayes, and the Lake Kaituna and Lake Komakorau Care Group, have finally cleared more than 16 hectares of willow jungle, and reinstated native plants around the margins of both lakes.

Native sedges, rushes and shrubs flourished once free of the willow stranglehold. They help the wetland work like a sponge – keeping adjacent paddocks drier in the winter as the soil and plants soak up floodwaters, and wetter in the summer as the stored ground water is slowly released. All up this means greater productivity in adjacent paddocks. With funding from Environment Waikato, the Department of Conservation and a lot of volunteer work, the Care Group has also:

• Installed sediment traps on all inlet drains to both lakes.
• Cleared away 30 truckloads of household rubbish from the lake edge.
• Dealt to privet, blackberry and other weeds.
• Controlled animal pests including possums and feral cats.
• Re-planted native species.
• Developed areas for wading birds.
• Installed teal nesting boxes.
• Created a walkway around both lakes.

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