Yield gains of irrigated crops in Australia have stalled: the dire need for adaptation to increasingly volatile weather and market conditions

Abstract

The climate crisis demands the development of innovations that sustainably raise farm-gate profit under increasingly volatile conditions. Here, we review the literature on the Australian irrigated grains sector and show that yield gains have not progressed since 2002. We reveal a concerning trend of increasing demand for irrigation water on the one hand, yet declining availability of irrigation water on the other. We show that yield gains of Australian irrigated crops have not progressed since 2002, although the use of irrigation water has declined since 2013 and water-use efficiency of irrigated crops has marginally increased. These trends suggest that productivity gains realised by the adoption of new technology, skills and practices over time (including new crop genotypes, larger machinery, reduced tillage, automated irrigation sensors etc) have not been enough to overcome background changes in climatic and economic factors that influence yields of irrigated crops at the continental scale. We highlight a cruel irony that despite having the ability to alleviate water stress, farmers with access to irrigation are still very much dependent on rainfall, because low rainfall reduces regional irrigation supply and elevates water prices, making use of irrigation financially unviable. This, together with hastened crop development and higher risk of heat-induced floret sterility, has meant that the climate emergency has detrimentally impacted on yield gains of irrigated crops, although detrimental impacts have been mediated by rising atmospheric CO₂. We conclude that the greatest potential for improving the profitability and water-use efficiency of irrigated crops may be through adoption of integrated combinations of site-specific whole farm packages, including contextualised agronomic, financial and engineering interventions. Appropriate decision support system (DSS) frameworks can help users unpack some of this complexity, enabling land stewards to tactically navigate volatile climatic and market conditions to strategically plan for improved economic resilience and reduced climatic risk.