An independent report on landfarming in Taranaki has vindicated the science behind the process, Taranaki Regional Council boss of environmental quality Gary Bedford says.
In a report commissioned by the council, soil scientist Doug Edmeades, of AgKnowledge Ltd in Hamilton, set out to see if landfarms in Taranaki were fit for pastoral farming, in particular dairy farming.
Dr Edmeades investigated soil fertility, heavy metal and barium concentrates and petrochemical residues in the soil at three landfarming sites in the region.
The report found that landfarming made sandy, coastal farmland ten times better for dairying.
"The process of landfarming these otherwise very poor soils, together with appropriate management has increased the agronomic value of the land from about $3000-5000/ha to $30,000-40,000/ha."
Mr Bedford said the report confirmed what the council had always maintained about landfarms.
"We're satisfied we're getting the science right but we hadn't asked anybody to look at this from a farming perspective."
The council commissioned the report as part of continuous evaluation of the activities it presides over in the region.
The report concluded that concentrations of nutrients, heavy metals and soluble salts in the soils and pasture are similar to normal New Zealand soils.
"The form of barium present is an environmentally benign barite, and there is no evidence of accumulation of petrochemical residues."
Concentrations of heavy metals were compared to those in soils from various regions in farmed and non-farmed land and were found to be in the low end of the range.
In testing for petrochemical hydrocarbons, there were some occasions where the limit was exceeded, particularly on the most recently completed landfarm.
Dr Edmeades said these levels would decline over time as the soil's naturally-occurring microbial population broke down the hydrocarbons.
He said abundant earthworm casts at all sites were a good sign as the earthworm was regarded as the ‘canary in the mine' in regard to soil biological activity.
In an email sent to various organisations including the Taranaki Daily News, TRC candidate Sarah Roberts said she was appalled drilling waste from Gisborne would be dealt with in Taranaki. "I am incensed Taranaki Regional Council and our district councils believe this is acceptable. We are not the toxic waste dump for everyone else's garbage. We have enough issues dealing with our own."
But Mr Bedford said disposing of other peoples' waste was not something weird or unique to Taranaki.
"All around New Zealand, every day, waste moves between regions.
"It is not Taranaki putting itself into a bad light as being the dumping zone for the rest of New Zealand.
"We have consented, well-monitored, well-managed landfarms in Taranaki - why shouldn't we be in a position of accepting waste from other districts or other regions?"
- © Fairfax NZ News
Should the NPDC councillors get iPads?Related story: Tech-wary councillors hedge their bets