Therese McBeath 1, Pilar Muschietti-Piana1, Michael Moodie2, Andrew Ware3, Rick Llewellyn1 Vadakattu Gupta1
1 CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA, 5064
2 Mallee Sustainable Farming and Frontier Farming Systems, Mildura, Vic, 3400
3South Australian Research and Development Institute and EP Ag Research, Port Lincoln, SA, 5606
Despite recent increases of nitrogen (N) inputs and one of the highest levels of adoption of soil-specific inputs of N fertiliser, a crop yield gap attributable to N remains on sandy soils. Over a 5 year period inclusive of decile 1 through to decile 9 seasons we have explored the effects of the source, rate and timing of N for increased productivity and reduced economic risk in low rainfall wheat and canola crops. While N application at the optimal rate is a primary driver of productivity and can reduce risk, we have identified that the N input for both wheat and canola is relatively insensitive to the timing of application. Utilising legumes in the sequence does increase the supply of N in the system, but the best productivity outcomes came from feeding wheat and canola with N from both legumes and fertiliser. A hybrid canola option has been shown to offer further yield gains per unit N input.