|
Nitrogen leaching and OVERSEER
I recently attended a DairyNZ workshop at Invermay to give an update on the nitrogen leaching rule and the use of OVERSEER. Key information included a reminder that nitrogen (N) leaching rates must be met from 1 April 2020. The leaching rate is calculated as an average across all of the area located over the relevant N loading zone within the property. The leaching rate is assessed by OVERSEER.
There are three nitrogen (N) sensitive zones with varied leaching rates per hectare per year. The zones are:
- Alpine lake catchments, which have a 15kg per hectare N limit
- Specific aquifers, which have a 20kg per hectare N limit
- The rest of Otago has a N loading limit of 30kg per hectare
Please click here to find which zone you are in.
ORC encourages all properties to have an OVERSEER report prepared now, ready for when the new rules kick in on 1 April 2020, so landholders know what their number is in relation to the N limits. The report must be prepared by a Certified Nutrient Management Adviser. Click here to find a list of Otago advisers. There have been refinements to OVERSEER over time so the model now more accurately assesses the N leaching number. It should be noted that the nitrogen sensitive number in the water plan remains the same per zone despite any changes within OVERSEER, as the model becomes more refined. For water plan rules on OVERSEER, please see the "In Brief" section below. |
