The Wednesday 8 November workshop is being run by the Northland Regional Council and will examine both how the land can be farmed to minimise soil losses and the downstream effects of sediment, nutrient and microbial runoff.
Vincent Lane, of the Northland Regional Council, says recent data from Landcare Research shows the country loses more than 200 million tonnes of soil every year to the oceans through erosion and runoff.
Mr Lane, a Catchment Management Officer for the Regional Council, says Northland’s geography and geology means it too will be suffering significant annual soil losses.
Aside from the obvious economic costs of losing potentially productive farmland to waterways, there are also less well-known, but serious - effects on estuaries, harbours and other water bodies.
“Few people realise that soil – while a natural substance – is actually one of the most serious and common pollutants of Northland’s waterways, especially if it is carrying nutrients and bugs with it. Sediment can smother and infect shellfish and also speed up siltation, which in turn promotes the spread of mangroves.”
Mr Lane says runoff from Northland paddocks – especially during the wetter winter months – can carry many tonnes of sediment in a relatively short period.
“Where there is little or no vegetation to stop its progress, this material washes from the paddocks, flows into the streams and on into the region’s estuaries and harbours.“
He says the 8 November workshop is being held at the Waiare Rd, Kaeo, farm of Doug and Sally Lane. “Over the past several years, the Lanes have changed the way they farm their 200ha property to maximise productivity on suitable land while retiring and commercially planting steeper, erosion-prone sections.”
Mr Lane says the 10.30am to 1pm workshop will include Raglan-based speaker Fred Litchwark, who will outline the work of Waikato’s Whaingaroa (subs crrct: Whaingaroa) Harbour Care group.
The group has planted hundreds of thousands of native plants in the Whaingaroa (Raglan) catchment to reduce sediment runoff that had been fouling the harbour.
Northland Regional Council speakers will also discuss sediment and other local environmental issues and Mr Lane says at the conclusion of the workshop, participants will have a chance for an informal chat over light refreshments.