Spring soybean evaluation, Grafton, NSW 2020–21

Abstract

Key findings • The highest yield (5.79 t/ha) was produced by variety Gwydir[PBR] from the earliest planting date (PD1, 8 September 2020). • RichmondA and Gwydir[PBR] were the highest yielding varieties across three spring planting dates (PD1: 8 September, PD2: 13 October, PD3: 13 November). • Burrinjuck[PBR] and Moonbi[PBR] produced the lowest yields across all planting dates. • The southern NSW variety, Burrinjuck[PBR], showed susceptibility to powdery mildew in the northern NSW environment and low pre-harvest weathering tolerance, which led to grain quality downgrading. • Maturity of the varieties in PD1 ranged from 118 days to 163 days, with harvesting ranging from 4 January to 18 February 2021 respectively. • The risk factors for soybean crops planted 4–8 weeks before the commencement of the traditional coastal planting window include: inadequate soil moisture to establish dryland crops; slower germination and emergence due to cold soil temperatures; early incursions of insect pests particularly pod sucking bugs and the potential for leaf diseases such as powdery mildew or soybean leaf rust to develop during cooler spring conditions.