In 2018 the Parliamentary Commissioner for the Environment recommended a review of Overseer be undertaken. An independent Scientific Advisory Panel was subsequently established by the Government to undertake this work.

Within the Panel's report to Government on Overseer it concluded that, in its current form, it would not have confidence in Overseer's estimates of nitrogen lost from farms. In response to the Panel's findings the Government has decided to put in place one or more of the following options:

a) the creation of a new risk index tool, potentially using elements of Overseer (including the user interface); and
b) development of a next generation Overseer to address the issues raised by the Panel in ensuring that it is fit for purpose as a tool to use in appropriate regulatory settings; and/or
c) greater use of controls on practices and inputs to manage nitrogen loss (including through amendment to the NES-F); and/or
d) a completely new approach to understanding and managing diffuse nutrient loss risk. This might include near real-time monitoring of water quality at the local scale or a new nutrient loss tool.

Based on the options listed above it is quite clear that significant changes would be required to Overseer before Government accept a revised version of the tool that regional councils can use to effectively manage nutrient discharges off-farm. In charting the options, the Government has signalled its commitment to the next generation Overseer tool that will be able to incorporate innovations that are proven to lead to improved outcomes for fresh water quality.

It is generally acknowledged that the Overseer model is far from perfect, as software modelling tools of farm systems rarely are, but it does provide the farming community with an expanded understanding of nutrient flows at a sub soil level which has helped farmers and their advisers to confidently map out a pathway forward to better manage the application of nutrients to improve environmental outcomes.

Overseer was never intended to be used as a regulatory tool. Nonetheless, for the lack of any other model or tool to estimate the amount of nitrogen and phosphorous leaving the farm system, regional councils have used it in granting resource consents. This has led to the extended use of Overseer in other areas, including land valuations, bank financing arrangements and to support environmental credentials in marketing our primary products to the world.

It is therefore timely to take stock of what we might lose should Overseer and potentially other farm systems scenario-based modelling tools were to be pushed into the background in favoured of a more restrictive input and control-based approach that is also listed as an option under consideration by the Government.

While standardising the level of inputs that can be applied on-farm and/or setting controls on certain farm-based activities may have some appeal for policy makers in meeting environmental targets, this blunt instrument would be counterproductive in encouraging the development and uptake of new and innovative on-farm practices or technologies aimed at providing better environmental outcomes, particularly if farmers are not going to be recognised or rewarded for such efforts.

This could also apply to private and public research organisations when considering their future research priorities. For example, what incentive is there for plant breeders to make long term investment decisions in researching and developing new plant cultivars with positive environmental benefits if those attributes are not going to be recognised through a nationally endorsed farm systems modelling tool. More so if there is uncertainty around policy settings to adequately recognising new technologies that improve on-farm environmental performance.

Outside of Overseer and Farmax there is a limited range of sophisticated software modelling tools to test complex farm systems scenarios impact on water quality and greenhouse gas emissions. These tools have provided the opportunity for farmers and their advisors to develop plans that not only provide better environmental outcomes, but also build sustainable and profitable farming businesses into the future.

It is important that farmers and advisors have confidence in farm systems modelling tools that can robustly test new and innovative farm management practices within the context of the farm system as well as recognising the latest technologies in providing better environmental outcomes. While Overseer has been mauled by the Panel, the opportunity now exists for the organisation to define its core role within the primary industry and ensure the tool is match fit going forward.