Overseer was developed 30 years ago to determine fertiliser application rates on pasture and has supported farmers to learn more about nutrient loss from their farms. It is jointly owned by the Ministry for Primary Industries, the Fertiliser Association of NZ, and AgResearch Ltd.
The Ministry for Primary Industries, AgResearch, and the Fertiliser Association of New Zealand each hold one-third stake in the Overseer intellectual property. In 2016, they established Overseer Limited to manage, develop, and license Overseer for use.
Overseer Limited released OverseerFM in June 2018. This paid software service is part of an agreed business plan. OverseerFM is updated regularly – details are available at the OverseerFM website.
Technical review, findings and next steps
Overseer has undergone a rigorous technical review following recommendations by the Parliamentary Commissioner for the Environment (PCE) in the report Overseer and regulatory oversight: Models, uncertainty and cleaning up our waterways 12 December 2018.
In the context of the Government’s 2020 freshwater reform and water quality goals, it is important for farmers to have confidence in the tools they use to meet regulatory requirements.
Read the findings of the review and Government proposals for nutrient loss estimation tool development below.
Government response and recommendations [PDF, 846 KB]
Overseer review findings
The Scientific Advisory Panel undertook a rigorous review of the Overseer model in line with international best practice methods.
The Panel concluded that, in its current form, it would not have confidence in Overseer’s estimates of total nitrogen lost from farms. They identified a general concern with the model structure as well as some specific areas of concern.
The Panel found that the use of average climate data, homogeneous soil profiles, and the assessment of only one species of nitrogen meant that Overseer estimates do not comprehensively account for nitrogen losses in some catchments and for some land uses.
The Panel did not assess Overseer for ease of use, its data files, nor its part in supporting farmers to adopt management strategies that reduce a catchment’s nutrient load.
Find documents related to the technical review panel and process:
What happens next?
Government is committed to the development of a next generation Overseer along with a suite of tools to help in the management of on-farm nutrient loss.
Over the next year, the Government will further upgrade and test Overseer. It will be supported while the next generation of the tool is developed and additional tools are made available.
Many farmers and their advisers use Overseer to plan fertiliser strategies. It can continue to be used for this purpose. Overseer can still be used to predict a farm’s greenhouse gas footprint.
Overseer data has been used by some regional councils in recent years to support resource consents and planning. Regional councils will continue to implement their plans and administer consents to manage freshwater at the farm level. There may need to be adjustments in their approach in some cases. Government is working with regional councils to develop guidance material.
Who to contact
If you have questions about Overseer, email firstname.lastname@example.org