Simulating the efficiency and resilience of diverse crop sequences in Australia’s subtropical cropping zone

Jeremy Whish1, Lindsay Bell1, Peter DeVoil3, Andrew Zull2, David Thornby

1 CSIRO Agriculture & Food

2 Department of Agriculture and Fisheries, Queensland;

3 University of Queensland;

4 Innokas Intellectual Services

Abstract:

Farming systems in Australia’s subtropics have been under-performing. This study used simulation modelling to evaluate common crop sequences used in subtropical Australia in terms of their system water-use-efficiency (WUE) and resilience to climate variability. The analysis here examines this for 4 locations spanning the subtropical farming systems of eastern Australia. We found significant variation in the system WUE ($/ha/mm) amongst crop sequences, with common crop sequences in each location found to be 12-40% less WUE than the best crop sequence. Cropping intensity is a key driver of system profitability and risk, more so than a mix of crops used. Crop systems with higher intensities (i.e. less time in fallow) have higher average profitability but also higher risk; conversely, crop systems with longer fallows have a lower risk but there are trade-offs of lower long-term gross margins. It is critical to match cropping intensity to the environment to optimise the risk-return trade-offs. Lower crop intensities (0.5-0.75 crops/yr) are optimal in harsher environments (e.g. western districts), moderate crop intensities (0.75-1.0 crops/yr) in the moderate environments, but crop systems with higher crop intensities (1.0-1.3 crops/yr) are optimal in higher rainfall environments

 

Host

The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography david_marland@hotmail.com Graham Centre for Agricultural Innovation, Charles Sturt University

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