190kg/ha N Cap
190kg/ha N Cap Information:
On Monday 12th July 2021 NOSLaM hosted a workshop pertaining to the 190kg/ha N Cap. The workshop was facilitated by Sarah O’Connell and presented by Charlotte Irving, both from The AgriBuusiness Group.
Following the workshop, Charlotte sent us a raft of information both presented and alluded too during her presentation all of which you can access through the links below:
Her Powerpoint Presentation - click HERE.
The DairyNZ N cap decision tree – this explains the rules well. Found HERE.
A template on planning N applications – this will be relevant to farmers planning their 2021-22 applications - click HERE.
DairyNZ resource on skipping applications in January and February (in Canterbury) (found HERE), which has good advice on key checks to support this decision, including soil tests and clover herbage testing.
Information on the N fertiliser use on the Lincoln University Dairy Farm (LUDF) - click HERE. As Charlotte discussed, this was achieved largely by grazing at around 3 leaves/tiller, which resulted in +1 t DM/ha/year pasture. This is as 40‐50% of the ryegrass DM yield in a regrowth cycle is produced with the third leaf. Simply put “grass grows grass”, more leaves capture more light = greater photosynthesis. There were a few concerns from the audience on the impact that lengthening the grazing round would have on pasture quality. This document shows the round lengths, average leaf stage, and average pre and post-grazing cover across the season, as well as pasture quality.
OverseerFM has sent me recent regional reporting information completed for the Otago region (click HERE), which aggregates a range of results from the OverseerFM Farm Accounts in the Otago region. This will enable farmers with OverseerFM to determine where they sit relative to the Otago region.
There was a question on the impact of applying liquid N fertiliser vs the conventional solid urea applications. As discussed, a trial at Lincoln University over the 19-20 season using 25 kgN/app concluded that liquid N applications produce similar yields and quality to the urea applications, regardless of timing frequency within a month. However, as noted, LUDF has efficient irrigation systems, and different soils / climate to farms in North Otago, so it is important to take these factors into consideration.
More information is found HERE.
There was a question about where the 190 kgN/ha figure came from. Charlotte has done some digging and come back with the following: - The Regulatory Impact Assessment (click HERE (page 120-121) “considered that it was feasible, as DairyNZ data suggests that rates above [190kgN] are not able to be justified economically, as the pasture response curve flattens out beyond 200 kg”.
As I suspected, they draw from the successful LUDF example at reducing N fertiliser, which found that reducing nitrogen fertiliser from 313 kg N/ha to 178 kg N/ha (and associated stocking rate changes) reduced nitrogen leaching by over 30%, as well as greenhouse gas emissions by 20%.
Charlotte closed the workshop reminding attendees that if you are facing a significant reduction in nitrogen fertiliser, you are not the only one!
There is a lot of support from consultants and industry, as well as some great resources available. If you are wanting independent advice to help you make informed decisions Charlotte advises she will be happy to talk with you on 027 310 1438.