The SFS Variety by Management (VxM) trials are a core part of our trials program at SFS, and for the past several years have included various nitrogen management strategies as we continue to unlock nitrogen management research. This year was no different, with a focus on how to best optimise profit with the cost of urea becoming an issue. The trials were designed to look at how the timing of urea purchased, and therefore application would affect gross margins.

For each variety in the trials there are five fertiliser treatments:

1. High rate of N targeting 4t weighted early season
2. High rate of N targeting 4t weighted mid-season
3. Mid-rate of N targeting 3t weighted early season
4. Mid-rate of N targeting 3t weighted mid-season
5. Nil N

Treatments with N weighted early have assumed urea purchase in late March/early April to be ready for sowing, and N weighted mid have assumed purchase in June, when prices were slightly less.

Calculations for urea rates were based on soil starting N and assumed mineralised N. Urea applications went out at four different timings, and were broken up into percentage of total urea required:

N weighted early treatments

• 25% applied in furrow at sowing
• 50% applied at 4-6 leaf
• 25% applied at green bud

N weighted mid-season

• 25% applied at 4-6 leaf
• 50% applied at green bud
• 25% applied at stem extension

With some newly released varieties included in the trials across all crop types, make sure to keep an eye out for members only express trial results, which will be coming out within a week of the trial  harvest so you can start planning for sowing 2023!