Agronomic drivers of yield in rain-fed wheat production systems – Liverpool Plains

Abstract

Key findings •• Sowing wheat varieties in the early part of their optimum sowing window was found to be a key determinant of yield. Delays in sowing date (SD) averaged across sites resulted in yield losses of 13% for EGA GregoryA and ranged from 8% to 28%. •• Commercially available mid–late maturing spring wheat varieties (e.g. EGA GregoryA) were observed to be broadly adapted and plastic in their yield responses, performing consistently across sowing windows. •• Altering variety and/or maturity type, and increasing target plant populations in response to delays in SD could not fully compensate for the yield losses associated with delayed sowings. •• Yield responses to nitrogen (N) and phosphorus (P) fertiliser application rates, were variable and influenced by the starting soil nutrition and seasonal conditions. •• Crown rot (CR) was shown to be a significant factor influencing yield potential in inoculated vs. uninoculated experiments – the delayed SD decreased yields by 12%. Results highlight the compounding negative impact of delayed sowing and CR infection on yield potential and underline the need for awareness of risk levels from soil-borne pathogens before sowing in order to guide management decisions.