Effectiveness of agronomic practices in dealing with climate change impacts in the Australian cotton industry — A simulation study

Climate change is threatening the viability of cotton production in one of the world's leading cotton regions but we do not know the magnitude of the threat and how effective the common management options are in responding to the threat. This study aims to answer these two questions by using a system modelling approach under various climate change and management scenarios. To construct local climate change scenarios (CCSs) for key cotton production areas in eastern Australia daily outputs from the CSIRO Conformal Cubic Atmospheric Model driven by four general circulation models (GCMs) were used in a stochastic weather generator, LARS-WG. These CCSs were then linked to a process-oriented cotton model (CSIRO OZCOT) to quantify the effect of changing planting times and irrigation scheduling triggers on cotton lint yield, water use, and water use efficiency (WUE) in 2030. We considered four planting times: normal planting, 15days early, and 15 and 30days later in both irrigated and rain-fed cotton. For irrigated cotton, we considered two soil water deficits (50 and 70mm) below which an irrigation event was triggered in nine cotton production areas (Emerald, Dalby, St George, Goondiwindi, Moree, Bourke, Narrabri, Warren and Hillston). For rain-fed cotton, we considered three row configurations (solid, single skip and double skip) in four production areas: Emerald, Dalby, Moree and Narrabri.