All That's Green Is Gold

New Zealand stands out among developed nations because half of our greenhousegas emissions come from agriculture. The billion-dollar question is how we maintain productivity while reducing emissions.

- Veronika Meduna

 

In the middle of the patchwork of paddocks along State Highway 53, between Featherston and Martinborough, is a hint of a more ancient Wairarapa, a tiny stand of kahikatea with their roots anchored deep in a bog.

The wetland is artificial, constructed around a remnant of native trees on a dairy farm by a group of landowners firmly focused on the future of farming.

Kaiwaiwai Dairies milks 900 cows during peak times. The cattle graze on about 360ha of pasture and produce calves twice a year to deliver winter milk for Fonterra. The wetland, built on a productive but soggy section of the farm, is just one in a number of initiatives to reduce its carbon footprint.

In an office building behind the farmstead, Aidan Bichan, dairy farmer, farm consultant and one of seven shareholders, is crunching the numbers. The Kaiwaiwai wetland was created in 2014 to reduce nitrate leaching into Wairarapa Moana – the largest wetland area in the southern North Island, encompassing Lake Wairarapa and Lake Onoke – with financial assistance from the Ministry for the Environment’s waterways restoration fund. Since March 2015, monthly measurements have delivered data on what goes in and what comes out.

It shows that the wetland removes about 500kg of nitrogen a year from the water.

“It takes most of the drain water from our neighbours,” says Bichan. “Probably 30ha of our farm goes through that wetland and several hundred hectares from other people. It makes a difference to Lake Wairarapa, so it doesn’t matter whose nitrogen it is as long as it’s no longer in the water.”