The recent review of Overseer carried out by the Government has formally identified many of the already known inadequacies with its use as a modelling tool, but it has also identified a few other issues with the way that the model calculates the results and the way that they are being used that have caused us to pause and re-examine its use.
We at the AgriBusiness Group are confident that the Overseer farm modelling tool can emerge from this period stronger.
New Zealand farmers are building up a head of steam in reducing nitrate leaching to the benefit of our waterways and our market position. OverseerFM has been pivotal in helping farmers on this path because it’s been the only readily available tool that gives them an idea of their performance in terms of nitrate leaching.
The recent release of the Overseer Whole-Model Review report expresses a lack of confidence in Overseer and as a result, the Government plans to look at improvements or alternatives for use in regulation.
There’s no question that Overseer can be improved, but it’s important we keep using it in the meantime as a tool to support decision-making, because there is no other readily available option for farmers to model what’s happening to nutrients on their farm.
The AgriBusiness Group provides advice to farmers all over NZ. My colleagues and I know the majority of farmers are striving to reduce nitrate leaching and improve their environmental footprint.
It’s important they have the right tools to help them and Overseer is a useful tool when used in the right context to understand the impact of practice changes and inform plans.
I have confidence in the application of Overseer when it is used in this way. It gives farmers an indication of whether they are improving in terms of reducing nitrate leaching and gives them information to report to their regional council.
Regional councils require proof that farmers are making the changes needed to achieve regional goals for water quality. That can be demonstrated by developing a farm environment plan and monitoring progress against that plan, as is already happening in a number of regions.
Overseer is a tool to provide information on which to base farm environment plans and model progress in terms of the potential impacts of system changes. When using such tools, the relative accuracy of their use should be kept in mind when the farmer is considering the results.
There’s evidence that this approach, using Overseer as a farm management tool, is working.
In Canterbury, farmers are making changes. Overseer modelling informs their farm planning and through this planning they are increasing the efficiency of their systems both in the use of inputs such as nitrogen fertiliser and in terms of outputs such as milksolids or meat.
This approach to improving water quality means decisions about what to do on-farm are in the hands of farmers. That’s vastly preferable to the alternative, which is when the Government decides what farmers can do by setting input controls.
We currently have one example of this, where the Government has set a limit on nitrogen fertiliser use on dairy farms.
To avoid further input controls of this type, we need to keep using and improving Overseer to demonstrate that farmers are reducing their environmental footprint.
Who am I? Stuart Ford is the director of AgriBusiness Group
