To explore how much nitrogen is required to maximise mungbean yield and whether well-nodulated mungbean achieve the same yield as fertilised crops.

1. Mungbean did not respond to nitrogen fertiliser with a 1 t/ha yield and a starting soil nitrogen of ~90 kg N/ha.

2. Mungbean has limited ability to maintain its water balance in high evaporative conditions. Timely in-crop rainfall/irrigation may still not maximize yields under very hot conditions during flowering to pod fill.

3. Irrigation decreased canopy temperatures by up to 8°C. 

4. Charcoal rot levels increased, with the greatest rise occurring in the irrigated trial.

A field experiment was conducted at Hopeland, near Chinchilla. The site was selected for its low soil mineral nitrogen at the time of preliminary sampling (50 kg N/ha, 0-90 cm, 19/07/2019), and the ability to flood irrigate. Both a spring and summer planted trial were conducted in the same field; this report outlines details of the spring planted trial. Deep phosphorus (P) was applied across the whole site on 2 September 2019 to rectify a potential P deficiency. The P was applied as MAP at a rate of 100 kg/ha, 20-25 cm depth and 50 cm spacing. Nitrogen applications were surface spread on 24 September 2019 (Table 1). All treatments were replicated four times and repeated with and without irrigation to alter yield potential. A pre-sowing irrigation (flood) was applied across the site on 3 October 2019 to enable planting. Mungbean was then planted on 14 October 2019 with Jade-AUP at 50 cm row spacing with 40 L/ha of Flowphos 13Z. The ‘double starter’ treatment had 80 L/ha applied. REGIONAL AGRONOMY (RESEARCH) | 3 The paddock nitrogen status at planting (control plots only) was 58 kg N/ha for the irrigated trial and 89 kg N/ha for the dryland trial. All treatments, except treatment 1, were inoculated at planting through water injection.