[12 December/Rural Life]

The Parliamentary Commissioner for the Environment, Simon Upton, has released a report where he provides his assessment over whether Overseer should be used to regulate farmers with respect to water quality. Mr Upton said New Zealand has a major water quality problem associated with nutrient losses from farms and it was time to open up the software to greater scrutiny, to ensure Overseer’s outputs are reliable. Overseer takes nutrients that are present or introduced to the farm, including nitrogen and phosphorus, models how they are used by plants and animals on the farm, and then estimates how they leave the farm and in what form. Sediment and pathogens, such as E. coli, fall outside the model’s scope. The tool is jointly owned by the Ministry for Primary Industries, AgResearch and The Fertiliser Association of New Zealand (which is a trade body representing the two major manufacturers of superphosphate and nitrogen fertilisers – Ballance Agri-Nutrients and Ravensdown). The report concludes it is possible to deliberately manipulate Overseer outputs, making it look like nitrogen loss had reduced on paper, when in practice it had not. There are also problems when the software is updated as this can change outputs and render some farms non-compliant, when in fact the practices on the farm had not changed at all. The report makes ten recommendations, including providing greater transparency around how the model works and aligning its ownership, governance and funding arrangements with the transparency required for it to be used as a regulatory tool. He said there also needs to be official guidance on how Overseer should be used by regional councils.