Overseer does what it was designed to do

Recent criticism of Overseer, a tool many regional councils have been using to help them regulate water quality, is misguided, writes Caroline Read.

CLAIMS that OverseerFM is a “mess” and not “up to the job” are well wide of the mark (Overseer oversight found wanting, ODT, August 16, 2021).

First and foremost, it is important to understand what OverseerFM is — and what it’s not.

OverseerFM is a farm planning and management tool, which helps farmers and growers make better decisions to improve their farm’s environmental sustainability and productivity, including when it comes to nutrient budgeting. It provides a way to estimate how nutrients are cycled within a farm system.

OverseerFM does not measure nutrient loss in real time and it was never designed for this purpose. The peer review saw this as a weakness, but our independent science advice is that Overseer’s approach of estimating cumulative annual nutrient losses is suitable to support the sort of scenario testing OverseerFM is most often used for, and which is of greatest value to our users.

Put simply, OverseerFM failed at something it was never designed to do. It’s like an Olympian being judged as failing in the high jump when they were competing in the shot put.

What we know is that OverseerFM is proven in its ability to support farmers and growers make more informed decisions about their farming practices that help improve their environmental performance.

It’s a sophisticated indicator of risk that considers the reality of a farm situation. Feedback from many farmers, scientists, rural professionals, regional councils, Beef + Lamb New Zealand and DairyNZ all back this conclusion.

We do welcome scrutiny and feedback on the OverseerFM science model and Overseer Ltd is always looking to develop and improve the utility and reliability of OverseerFM across the full range of its uses. We have never said the tool is perfect; no model can do everything.

The review report does raise some valid points on how to improve some of the submodels used within the OverseerFM science model that we are keen to explore in order to further develop the tool.

In line with this, we are already working on reflecting nitrogen (N) uptake of deeprooted plants and looking to update and incorporate new crops into OverseerFM.

However, we have concerns with the conclusions reached in the report about the reliability of OverseerFM’s results because they were not sufficiently supported by testing and are contrary to the results of previous scientific reviews and more than 15 years of use by experts.

We do not agree with the suggestion that only a precision measuring tool operating in real time will deliver effective freshwater management for New Zealand.

Overseer Ltd is firmly focused on what happens next as a result of this review and we aim to ensure that OverseerFM continues to be as useful in the regulatory space.

But OverseerFM is much more than a regulatory compliance tool and its future lies just as much in the other facets of farm planning and quality assurance that OverseerFM already supports.

In the meantime, Overseer Ltd remains confident that the software does what it was designed to do.

Farmers and rural professionals can keep using it — consistent with our guidance — to help make more informed decisions by modelling the impact of changes in farm practices.

Dr Caroline Read is chief executive of Overseer Ltd.