Effect of August 2020 changes to S-maps on OverseerFM results

Manaaki Whenua Landcare Research will be updating soil parameters in their S-map tool in late August 2020. For more information on the detail of these updates see here

Overseer Limited will not be updating all analyses automatically following the update to S-maps. Instead, we have introduced a “Check for S-map soil updates” button within each farm account. For guidance on using this see here.

Overseer Limited have carried out comprehensive testing of the new S-map parameters on 32,000 analyses in OverseerFM to identify the likely changes that will occur in relation to N-loss and GHG emissions.

The results summarised in the table below identify the likely significance of changes to N-loss and GHG expected.  

For N-loss, we can see that just under 15% of farms will see no change, meaning most farms should expect some change. For the majority of the farms (71%) the changes will be between -10% and +10%.

There will be a reasonable proportion of farms (around 17%) that will see a greater than 10% increase, but less that 20%. And there will be a further 8% who see extreme increases of over 20%. There are also a few farms that will see a significant decrease in N-loss results.

99.98% of farms will also see their GHG emissions per hectare result change between -10 to +10%, with very minor significant changes.

When interpreting these results please note that it is likely that not all farms in OverseerFM use the current S-map information. Many legacy Overseer nutrient budgets uploaded into the software in 2019 may have included older S-map information. These results don’t attempt to provide an exact representation of the impact of the latest changes, but they are a true reflection of the result of updating existing data to the latest S-Map data.