Penny Roberts1, Michael Moodie2, Nigel Wilhelm3
1 Penny Roberts, PO Box 218, Milang, South Australia, 5256, firstname.lastname@example.org
2 Moodie Agronomy, Mildura, Victoria, 3500, email@example.com
3 South Australian Research & Development Institute, PO Box 397, Adelaide, South Australia 5001.
To quantify the benefits of break crops in the low rainfall region of south eastern Australia, five trials were established at Mildura (VIC), Minnipa (SA), Appila (SA), Chinkapook (VIC) and Condobolin (NSW). To further develop confidence in the trial outcomes at a regional level, the results were extended using the farming systems model APSIM across a range of seasons and a variety of soil types, including additional locations Loxton (SA) and Carwarp (VIC). At the majority of sites a legume increased the following wheat yield by 67-854 kg/ha, over a run of the previous 100 seasons. Wheat was the lowest risk crop, being the crop type least likely to yield less than 500 kg/ha. At Loxton and Carwarp break crops had yield potentials greater than 500 kg/ha in 50 – 80% of years. This was also the case for oats and fieldpea at a further 2 of the 6 sites. Soil type was an important determinate of break crop success, with pulses, lupin and chickpea performing poorly on constrained soils. The modelling results give greater confidence for increasing the percentage of break crops grown in the low rainfall farming systems of south eastern Australia through careful species and paddock selection. However, there is still a need to focus on addressing the constraints to break crops achieving water limited yield potential in these environments.