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Answers to some frequently asked questions

This page includes:

About Overseer

What does Overseer do?

Overseer models nutrient flows on a farm, delivering nutrient analyses that show what is coming in and going off the farm – when, how and where.
The software uses readily available farm information to predict nutrient losses and greenhouse gas emissions for that farm based on farm management practices.
By modelling different scenarios, farmers can make decisions about management approaches that can improve efficiency in their use of nutrients, improve environmental outcomes, and increase profitability.

How does Overseer work?

Overseer uses existing science understanding (built into a series of sub-models) and readily available farm information to predict the flows of nutrients into, around and off the farm - this is most commonly used to understand nitrate leaching and greenhouse gas emissions.
You can read more in our Overseer Technical Description.

Who owns Overseer?

The Overseer software is jointly owned in equal shares by the Ministry for Primary Industries (MPI)AgResearch Limited and the Fertiliser Association of New Zealand (FANZ).
The owners established an independent company Overseer Limited in April 2016 to ensure the long-term viability of Overseer and meet growing user needs.
The company is jointly owned in equal ordinary shares by AgResearch and the Fertiliser Association of New Zealand. The Ministry for Primary Industries has equal voting rights alongside the shareholders. It is therefore considered a Public Entity.
Overseer Limited is chaired by one of its two independent Directors and is required to re-invest income into the ongoing improvement of Overseer.

How accurate is Overseer?

Overseer is a modelling tool founded on over 30 years of scientific research. All models are simplifications of complex science, and their predictions will always involve uncertainty. Overseer is no expection. We calibrate Overseer against available real measured data to ensure where those situations exist, there is greater certainty in the results. We also peer review and test the science model so that we are confident that it is doing what we think it should.  
Good quality farm data is essential to good quality Overseer predictions (rubbish in equals rubbish out) and so we have created the Best Practice Data Input Standards to ensure users are guided in identifying the best source of data when using Overseer.

Why does the model use long term averages?

Actual leaching from a farm block will vary, sometimes quite significantly, year-on-year due to variations in weather. Because Overseer was designed to help farmers test the impact of different farm management practices, it removes short term variability (such as weather events) so farmers can make good decisions for the long-term. The model therefore estimates how much nutrient leaching or gas emissions are likely to occur in a typical year if the management system described remains in place. It is not a one-off prediction for a single year. You can read more about this in the Technical Guidance document.
The Overseer results are therefore best used to create a baseline for each farm, and to guide and measure improvement over time. 

Can Overseer predict what’s happening in a particular waterway?

Overseer looks at what is happening on a farm, and the modelling stops at the farm boundary. The tool estimates what nutrients are lost beyond where plants can access it in the soil profile (60cm for pasture, 120cm for crops). Overseer can only help understand what’s happening in local waterways by feeeding information about whats leaching from farmland into catchment models.


Using Overseer 

What is the user portal?

The Overseer user portal is a page where users access the tool’s applications and engage with us about using it. It includes:

  • A dashboard for important notices and updates
  • A support page with a search engine for users to look up common questions
  • A helpdesk to contact technical support
  • The user guides and best practice data standards 
  • Science model information including version update release notes and details about the model engine.

What help is available when using Overseer?

Overseer helpdesk is available for any questions that are not listed on the support page. You can log your request through the user portal or email us at Please note, we do not provide an advice service. We aim to respond to emails within 24 hours, unless it is a weekend or public holiday.  

What computer equipment do I need when using Overseer?

OverseerFM is an online application, so you can use it from any computer with internet access. Requirements for the legacy OVERSEER Nutrient Budgets standalone application are listed on our support page.

Can I get training to use Overseer?

Comprehensive training for regular users of Overseer is available through the sustainable nutrient management courses provided by the Fertiliser and Lime Research Centre. These courses use Overseer to illustrate principles in nutrient management.
Massey University, Lincoln University and Waikato University include Overseer as a part of their undergraduate agricultural degree courses.
The industry has established a Nutrient Management Adviser Certification Programme (NMACP), in response to the growing need for sound advice on nutrient management, including producing Overseer nutrient budgets and scenarios. This programme certifies individual advisers, using a transparent set of industry standards. You can find out more on the NMACP website.

Is Overseer free to use?

OverseerFM is free to use until January 2019, and will then be available on a subscription basis. This will ensure sustainable, ongoing investment in and development of Overseer. Our founding principles around public good and increasing value for New Zealand will underpin our charging policies.
The legacy OVERSEER Nutrient Budgets also remains free to use for the remaining time it is available.

Starting out with OverseerFM

How can I use OverseerFM?

To use OverseerFM, simply register at
All users will need to register first, including previous users of the legacy OVERSEER Online. You can read more about this in our information sheet registering for OverseerFM

Can I use the existing data file that was created in the legacy OVERSEER Nutrient Budgets?

Users can upload XML farm files from the legacy OVERSEER into an OverseerFM farm account, provided they were created (or have been updated to) version 6.2.3 or version 6.3.0. Farm information from earlier versions of OVERSEER are not supported in OverseerFM.

How is data stored in OverseerFM?

OverseerFM farm account information will be stored in a central database. This was set up in response to concerns that there was significant duplication of effort within the industry as different parties modelled the same farm separately. The centralised data storage will also deliver greater auditability of analysis for quality assurance, and provide an easy transition between model updates.

Who can access the data?

Once a farm account owner (farmer or farm manager) is registered, the farm account owner decides who should have access to their farm information. The farm account administrator can also grant and revoke permissions to information, and the farm account owner can control administrator access.
The Year-End analysis (which models historic management practices for baselining, monitoring and reporting) are available to all parties with permission to access a farm account. Predictive and scenario analysis are private to the business developing them. 

Can I save OverseerFM information on my computer or elsewhere?

All OverseerFM data is stored in a database on a secure server. A farm account owner can share access to their farm account information held in this central database by giving permission to other registered users. It is possible to update farm account information offline, however an internet connection is required for the model to run.

Will information be shared with councils in the same way as it is now?

No. In the past, farm information has been emailed to the council as an XML file.
OverseerFM allows users to publish a specific analysis to the council for them to review via OverseerFM. This provides a secure and auditable process for providing councils with the information that they need to implement their plans. 


Using the legacy OVERSEER Nutrient Budgets

Can I continue to use the legacy OVERSEER Nutrient Budgets software?

The legacy OVERSEER Nutrient Budgets software will be available during a transition period online and as a standalone product, but it will be phased out in the first half of 2019. Go to