Industry good organisation DairyNZ endorses further redevelopment of Overseer to continue its role helping optimise farm systems to protect water quality, farm viability and economy.

DairyNZ strategy and investment leader Dr David Burger says science-based management and modelling reviews, such as the recent Government report into Overseer, helps improve nutrient management for the environment and farm businesses.

“Overseer is vital in helping farmers, the sector and councils understand farm management, particularly nutrient and greenhouse gas losses to the environment. Therefore, we must have a high level of confidence in it as a tool,” says DairyNZ strategy and investment leader Dr David Burger.

“It’s pleasing Government is committed to supporting Overseer and a re-development, while looking at other tools to improve nutrient management and on-farm outcomes.”

Dr Burger said DairyNZ research shows nitrate leaching measurements from farm system experiments are generally well-aligned with Overseer predictions where actual climate data has been used on dairy land.

“Along with this on-farm science, DairyNZ has contributed to improvements to the Overseer model, such as including plantain and updating the wetland and riparian modules. Our research and experience with farmers tells us Overseer is an important tool for helping dairy farmers manage nitrogen and reduce losses from farms.

“Falling back on input controls or reliance on risk factors is not an adequate substitute for output modelling, especially when we have an increasingly sophisticated range of nitrogen management options that Overseer enables farmers to model,” says Dr Burger.

“Farm systems are complex and there are a range of ways farmers can reduce their footprint. Overseer allows farmers to model different options in the context of their farm system – enabling innovation and flexibility.

“Looking ahead, we support the Government’s commitment to examine a wider range of tools to support nutrient and sediment management at farm and catchment scale. However, our advice is that new modelling techniques should be in addition to re-developing Overseer, not a replacement.

“Having a parallel approach maximises the chances that farmers and regulators will have fit-for-purpose tools for both the short and long-term. We welcome any next generation tools to ensure that nutrient loss estimate tools accurately inform how farmers can meet regulatory limits.”

In addition to Farm Environment Plans and tools such as Overseer, the dairy sector strategy Dairy Tomorrow includes a commitment to managing nitrogen loss and improving how nutrients are used.

“Nitrogen is not the only contaminant and dairy sector is increasingly focused on outcomes and, in particular, ecosystem health improvement.”