Agronomic drivers of yield in rain fed wheat production systems of Central West NSW – Trangie

Abstract

Key findings •• Sowing time for the wheat varieties was found to be the key determinant of yield potential. Delays in sowing date (SD) resulted in yield losses of 34% or 1.20 t/ha for EGA Gregory[PBR] averaged across years. •• Variety selection was also found to be a significant factor influencing yield potential, with the longer season variety Sunvale[PBR] being 16% or 0.6 t/ha lower yielding than LRPB Crusader[PBR] from an early SD. The shorter season variety LRPB Crusader[PBR] performed well across SD options in this environment. •• Increasing targeted plant populations was shown to increase yield potential by ~8% (0.2 t/ha) when SD was delayed, supporting the accepted principle of increasing the target plant population for delayed sowings. •• However, altering variety and/or maturity type, and increasing target plant populations in response to delayed SDs could not fully compensate for yield losses associated with delayed sowings. •• Yield responses to nitrogen (N) and phosphorus (P) fertiliser application rates were variable and influenced by starting soil levels and seasonal conditions. Significant yield responses of around 19% were achieved in response to P application, highlighting the importance of knowing starting soil nutrition values when trying to optimise yield potential.