The effect of nitrogen rate and timing on grain yield and grain protein of eight wheat varieties – Trangie 2012

Abstract

Key findings • Increasing the rate of nitrogen applied at sowing increased grain yield of all wheat varieties from an average of 1.5 t/ha at the nil N rate to 2.9 t/ha at the 100 kg/ha N rate. • The lowest N application rate (25 kg/ha) did not increase grain protein significantly compared with the nil N rate (8.3% compared with 8.1%). Grain protein was increased by 1% from the application of 50 kg/ha N at sowing compared with where no N was applied and increased by a further 1.7% from the application of 100 kg/ha N at sowing. • At the 50 kg/ha N rate, splitting the N application between sowing and Z31 or sowing and Z65 had significantly lower yield than where the whole application was made at sowing. • The soft wheat variety LongReach Impala and the prime hard variety EGA Gregory[PBR] were the highest yielding varieties in this trial, regardless of nitrogen rate. • Longreach Impala[PBR] and the durum variety Caparoi[PBR] had the lowest grain protein in this trial.