Report finds shortcomings in Overseer nutrient management tool
Government will support the development of a next generation Overseer alongside a suite of tools to help in the management and estimation of on-farm nutrient loss
Over the next year, Overseer will be supported while a next generation of the tool is developed and/or additional tools are made available
A more accurate way to estimate nutrient loss is important for farmers, the environment and brand New Zealand
The Government will help develop improved tools to manage and estimate total on-farm nutrient loss, Environment Minister David Parker and Agriculture Minister Damien O’Connor announced today.
The announcement comes after an independent Science Advisory Panel identified shortcomings with the current version of nutrient modelling software Overseer and concluded that it did not have confidence in its ability to estimate nitrogen lost from farms in its current form.
The Ministers today welcomed the government-appointed Panel’s report, which will help develop improved tools for farmers and regulators to meet future Essential Freshwater planning requirements.
“Despite its shortcomings Overseer has been a useful tool to build awareness and influence practices to manage nutrient loss at the farm and catchment level,” David Parker said.
“There is a robust body of independently peer-reviewed knowledge on nitrogen mitigation options that sits alongside Overseer.
“Farmers have used Overseer, alongside advice, to improve practices and freshwater outcomes.
“We encourage farmers to continue their vital efforts to reduce nutrient losses.”
Ministers recognise the urgency of the work, given the 2024 deadline for Regional Councils to develop RMA plans under the Essential Freshwater reform package.
“Our farmers and growers have put in a significant amount of work and investment over many years to boost environmental outcomes on-farm,” Damien O’Connor said. “The Government will seek to ensure improved tools for estimating nutrient loss are transparent, accurate and effective.”
“Options to be considered include developing a risk-based index, developing a next-generation Overseer to address the panel’s concerns, greater use of controls on practices to manage nitrogen leaching, and potentially longer-term developing a new approach altogether.”
David Parker said it was vital farmers and councils had some certainty over the next year. Councils will continue to implement their plans and the freshwater reforms.
Damien O’Connor said: “It’s essential that farmers and councils using Overseer have some certainty on how to proceed. For this reason, the Government will support work on a next generation Overseer.”
Regional councils will continue to administer consents to manage freshwater at the farm level although there may need to be adjustments in the approach in some cases.
“We’ve spoken with Councils, and they can proceed with developing plans on the basis that nutrient loss estimation, and risk assessment tools will be available for the preparation of those new plans by the end of 2024.” David Parker said
“We need to build on the progress that farmers have already made,” Damien O’Connor said.
Over the coming months, officials will develop best practice guidance for models used in environmental regulation and these will feed into approaches and tools in the longer term.
“The Government supports the development of a next generation Overseer and other nutrient management tools. Having fit for purpose tools now will support our farmers to deliver long-term environmental benefits across New Zealand,” Damien O’Connor said.
There are three main causes of water quality degradation – excessive sediment, microbial contaminants, and nutrients. These causes are addressed in different ways in Essential Freshwater and Overseer is a tool that is used for managing nutrient losses. For many of New Zealand’s rivers, the main nutrient challenge is excessive nitrogen in its various forms.
Overseer is a NZ-developed software tool that models the nutrient flows on to and off farms and farm blocks. It aims to provide a quantitative description of farm nutrient dynamics for a range of farm system types. It combines data on farm management, topography, soil and climate.
Overseer and its predecessors have been used for 30 years by many New Zealand farmers to estimate nutrient budgets and understand how nutrients are cycled on-farm. Recently, it has been used by a number of Regional Councils as part of their plans and consents to manage nutrient loss to rivers and groundwater.
It can be used on dairy, sheep and beef, milking goats, deer, outdoor pigs, kiwifruit, viticulture and some vegetable and arable crops to estimate the impact of management practice change on the use or discharge of several nutrients.
The Overseer intellectual property is jointly owned by the Ministry of Primary Industries, the Fertiliser Association of NZ and AgResearch. The intellectual property is exclusively licensed to Overseer Ltd, which is owned by the Fertiliser Association of NZ and AgResearch.