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OverseerFM release version 6.6.0 (crop N uptake)

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  • Updated

We released an update to OverseerFM on 15 November 2026. 

The update of the Overseer model to release version 6.6.0 draws heavily on findings from the Catch Crops for Cleaner Freshwater project, led by the Bioeconomy Science Institute (BSI) and supported by the Ministry for Primary Industries’ Sustainable Land Management and Climate Change (SLMACC) fund. 

Additional SLMACC funding supported the translation of the research into the Overseer model by the Overseer team working in partnership with BSI and subject to independent scientific review.   
The release includes two significant feature updates:

  • Updated crop coefficients, using documented experimental evidence. These include changes to nitrogen concentrations in harvested products and crop residues, crop growth curves and harvest stages.
  • Crop nitrogen uptake that responds to soil nitrogen availability. The model now adjusts the additional nitrogen a crop can take up above its base demand according to the mineral nitrogen available in the soil.

The release also adds five crop options and makes corrections affecting outdoor pig methane, crop root biomass and some dairy Grass-fed Standard reports.

Details of the changes made to the model can be reviewed in the attached release notes and for those who wish to delve deeper, a paper on the translation project which enabled this model version change was presented at the 2026 Grasslands Conference in Marlborough, and can be found here. 

 

To complement the release notes, users can also find attached two additional documents: 

  • Overseer Model Update 6.6.0 - Full Impact Assessment. 
    This document presents the impact of version 6.6.0 on modelled nitrogen (N), phosphorus (P), and greenhouse gas (GHG) results, evaluated across the full OverseerFM production database.
  • Overseer Model Performance Assessment 6.6.0.
    This document compares model results against measured leaching data from farmlet trials used in prior validation work. This work provides an assessment for both the pasture model and crop modelling. 

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