Wednesday, 17 July 2019 09:55

Urgent Overseer review needed – Upton

Written by  Nigel Malthus
The Parliamentary Commissioner for the Environment, Simon Upton, speaking at the recent FAR conference at Lincoln. Photo: Rural News Group. The Parliamentary Commissioner for the Environment, Simon Upton, speaking at the recent FAR conference at Lincoln. Photo: Rural News Group.

The Parliamentary Commissioner for the Environment, Simon Upton, has repeated his call for a full independent review of Overseer before any widespread adoption of it as a regulatory tool.

Upton reported last December on Overseer’s suitability for use in a regulatory context.

In the opening keynote address to the recent Foundation for Arable Research (FAR) conference at Lincoln, Upton said his report made 10 recommendations. 

The most important was that the relevant ministers must decide whether they want Overseer used in a regulatory context and, if so, then the other recommendations would come into play. 

Upton says no formal policy decision was ever made about Overseer. “Rather it has sort of muddled along, been used and built on here and there”.

He is still waiting for a Government response to his report.

“I’ve actually had nothing in the way of feedback and for the moment I’ve got no idea of the Government’s response to my recommendations, so that’s obviously still a work in progress.”

He says some indications appeared in the 2019 budget and in ministers’ comments, and Overseer was mentioned in the $229 million Sustainable Land Use package. But he is still waiting for a formal response.

Upton says Overseer’s ability to estimate diffuse loss of nutrients – including nitrogen at farm scale – has made it attractive to regulators.

“It is scarcely surprising that some regional councils have turned to Overseer because it provides estimates of the very environmental pressures that regulations need to be designed for,” he told the FAR conference.

But he added that Overseer operates on long-term averages, assumes average and constant management and site characteristics and relies on calibration.

“With its focus on experimental measurement and calibration in pastoral systems it models pastoral land uses best,” he explained. 

But as for arable farming systems, there’s much more limited research and calibration. Many crops are currently unrepresented on Overseer, and practices like double sowing of crops, rotation, regular cultivation and block management changes all run counter to Overseer’s underlying “average and constant” assumptions.

“Users of Overseer – whether farmers, farm consultants, researchers or regional councils – need confidence that the outputs of the model are sufficiently reliable for use in a regulatory context where powers of enforcement are being wielded and expectations are for public improvements rather than private gain.”   

Upton says he would have expected more rigorous formal scrutiny of the model, but there is no New Zealand-based guidance on the use of models in regulatory settings, and he had to turn to the US’s EPA to find a framework to evaluate it.

More like this

Will review fix Overseer?

Overseer Ltd says it welcomes the recent launch of an independent review of its environmental modelling software and is looking forward to working with the review panel.


Shine off dairy prices

Resurging Covid-19 across the globe is continuing to take the shine off previously high dairy prices.

Fonterra reacts to feedback

Fonterra's board is getting some kudos for listening to shareholder concerns as it works on a new capital structure.

West Coast resilience tested

DairyNZ head consulting officer in the South Island, Tony Finch, says his first priority has been to get an accurate…

Machinery & Products

One-pass cultivator moves 70% less soil

According to Kverneland distributor, Power Farming, the KultiStrip system will bring opportunities to farm environmentally, while improving yields and profitability.

Claas buys into bots

German harvesting specialist and tractor manufacturer Claas has acquired a minority shareholding in Dutch start-up company AgXeed, the developer of…

» The RNG Weather Report

» Latest Print Issues Online

The Hound

Oh yeah?

OPINION: The Hound reckons that meat company Silver Fern Farms is now drinking from the same Kool Aid trough as…


OPINION: Your old mate finds it rather ironic that the Government is going to open up the border to allow…

» Connect with Rural News

» eNewsletter

Subscribe to our weekly newsletter