Joseph X Eyre1,3 Loretta Serafin2 and Daniel Rodriguez1
1 Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland. Gatton Campus, Bld 8115, Gatton, Qld. 4343 Australia,
2 Loretta Serafin, New South Wales Department of Primary Industries (NSW DPI), 4 Marsden Park Road, Calala, NSW, 2340 Australia,
3 https://qaafi.uq.edu.au/profile/267/joe-eyre firstname.lastname@example.org
Lack of planting opportunities, water stress and high temperatures around flowering are major limitations to dry land sorghum (Sorghum bicolor L.) yield across Australia’s Northern Grains Region. Sowing summer cereals into cool moist soil can increase the likelihood of crop establishment, reduce the impact of high temperatures and dry spells around flowering, and have large benefits at the cropping system level by increasing the chances of double cropping. Here we, i) used parameterised APSIM to identify sowing windows that fit the flowering of sorghum during low heat and water stress periods, ii) evaluated commercial sorghum hybrid cultivars in winter (July-August) sowing windows on-farms in northern New South Wales (NSW) and southern Queensland (Qld), and iii) quantify impacts of the practice on the cropping intensity. Results showed that i) the ideal flowering window across the region falls within two periods, October-November and March-April, ii) to achieve these target flowering windows, sorghum should be sown during July-August when soil temperatures are sub-optimal ca. 12°C in some regions; iii) sorghum seedlings are tolerant of frosts (0°C), iv) winter sowing did not cause yield penalties and v) that winter sown crops harvested before mid-December offered an 80% probability (80% of the years) for double cropping chickpea; this contrasts with a 20% probability (20% of the years) for a November sowing. We conclude that winter sowing of sorghum could reliably maintain high and more stable grain production and increase cropping intensity.