Online tool helps farmers, land and waterways

A web-based tool is helping New Zealand farmers maintain their position as world leaders in nutrient management.

OVERSEER® Nutrient Budgets (Overseer) is a farm-scale nutrient management tool, one of a growing number of on-line tools supporting New Zealand farmers to farm better. The model has been in use for over a decade supported by its owners:  the Ministry for Primary Industries, AgResearch and the Fertiliser Association of New Zealand. As well as its role as an owner, AgResearch provides the primary role of developing and maintaining the model and producing the technical material that describes how the model works.

Overseer calculates nutrient inputs, transfers and outputs from individual farms based on information specific to that farm, producing a nutrient budget. This helps farmers and their consultants to examine farm-scale nutrient management options to optimise production and minimise losses of nutrients to the environment.

Being able to estimate nitrogen and phosphorous losses to the environment has also seen Overseer become an important tool for regional councils as part of their role in managing water quality.

“The demand for Overseer has grown significantly in the past five years, particularly since the introduction of the National Policy Statement for Fresh Water Management as this requires regional councils to set water quality limits,” says Overseer General Manager Dr Caroline Read.

“Regional councils use Overseer to help them quantify nutrient loss from agricultural land, which has broadened Overseer’s usage from being an on-farm decision support tool used by farmers, the fertiliser industry and consultants to being part of a water quality management process.

“Overseer is increasingly becoming an integral part of regional council water quality management plans. This enables New Zealand to apply an effects–based approach to managing off-farm nutrient losses and as a result is stimulating innovation in the agricultural industry’s approach to improving nutrient management.”

Overseer is developed collaboratively so that the assumptions used in the model are based on New Zealand conditions, include the most up-to-date science, and are agreed to by industry wherever possible.

“Advisory groups that include leaders in nutrient management science, modelling and agriculture as well as experienced advisers who use Overseer in their businesses, ensure that Overseer has the expert advice it needs to maintain and develop the tool,” says Dr Read.

“The opportunities in the continued development of Overseer are numerous as we improve our understanding of science and the potential of different farming practices.”

The software is freely available on line to farmers, their consultants and industry advisors. For more information visit the website at