To assess whether the optimum timing for applied N interacts with N rate in canola

• There was no interaction between N rate and N timing in this trial on the RR hybrid 45Y28 indicating that yield responses to N rate were the same irrespective of timing.
• Accumulated N in the canopy at harvest indicated that optimum yields were achieved with crop canopies containing no more 268 kg N/ha. The unfertilised contained 180N.

• Higher applied N rates (240N) produced N crop canopy contents of 300kg N/ha at harvest but significantly more N in the canopy was not associated with more seed.
• Yield of 4.3 t/ha was achieved by applying 80 kg N/ha. Increasing N rates above this level did not result in higher seed yields.
• Timing of N application had no influence on yield or grain quality (oil and test weight).
• Water use efficiency was 10.6 kg/mm and nitrogen use efficiency (NUE) was 59.9 kg N/t.