NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Pine Gull Road, Wagga Wagga, NSW 2650, Australia; Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Pine Gull Road, Wagga Wagga, NSW 2650, Australia.
NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Pine Gull Road, Wagga Wagga, NSW 2650, Australia.
Sci Total Environ. 2020 Apr 20;714:136806. doi: 10.1016/j.scitotenv.2020.136806. Epub 2020 Jan 18.
The rain-fed cotton industry in Australia is vulnerable to climate change due to its high dependence on seasonal climate and summer rainfall. The rain-fed cotton in eastern Australia is increasingly being incorporated into cereal crop rotations due to government regulation of water resources, restricting opportunities for irrigated cotton. The accurate quantification of future climate impacts on exposed cropping systems such as rain-fed cotton is required to identify effective agronomic practices and inform strategic industry planning for the expansion of Australian cotton industry. Our study utilized 32 General Circulation Model (GCMs) for four cotton-growing regions representing the geographic range of cotton production in eastern Australia. We assessed the climate impacts on rain-fed cotton yield for two future periods (2040s and 2080s) under the RCP4.5 (low) and RCP8.5 (high) emissions scenarios employing the processed-based APSIM-Cotton model. Our results showed that current cotton yields varied with planting date, and the magnitude of yield change was consistent with regional climate variations at four locations representing the current geographic distribution of rain-fed cotton production. Means from multi-GCM ensemble showed growth period temperature increased more under RCP8.5 in the longer-term (2080s). Growth period rainfall changes had significantly positive effects on yield at all planting dates over each site. The projected increases in rainfall were more evident at later planting dates for dry sites than early planting dates at wet sites. In addition, we found planting date had the greatest influence on cotton yield at wet sites, while GCMs accounted for a large portion of variation in cotton yield at dry sites. We conclude that later planting has a great potential to increase rain-fed cotton yields. This provides important insights for regional-specific adaptation strategies for the rain-fed cotton industry in eastern Australia.
澳大利亚的雨养棉产业容易受到气候变化的影响，因为它高度依赖季节性气候和夏季降雨。由于政府对水资源的管理，澳大利亚东部的雨养棉越来越多地被纳入谷物轮作，限制了灌溉棉的机会。为了确定有效的农业实践并为澳大利亚棉花产业的扩张提供战略行业规划，需要准确量化未来气候对暴露作物系统（如雨养棉）的影响。我们的研究利用了代表澳大利亚东部棉花生产地理范围的四个棉花种植区的 32 个通用环流模型 (GCM)。我们评估了在 RCP4.5（低）和 RCP8.5（高）排放情景下，两个未来时期（2040 年代和 2080 年代）对雨养棉产量的气候影响，使用基于过程的 APSIM-Cotton 模型。我们的结果表明，当前棉花产量随种植日期而变化，产量变化的幅度与四个代表当前雨养棉生产地理分布的地点的区域气候变化一致。多 GCM 集合的平均值表明，在较长时期（2080 年代），RCP8.5 下生长期温度升高幅度更大。在每个地点的所有种植日期，生长期间降雨量的变化对产量都有显著的积极影响。在较干燥的地点，后期种植日期的降雨增加更为明显，而在较湿润的地点，早期种植日期的降雨增加更为明显。此外，我们发现种植日期对湿润地点的棉花产量影响最大，而 GCM 则在干旱地点的棉花产量变化中占很大比例。我们得出结论，后期种植有很大潜力提高雨养棉的产量。这为澳大利亚东部雨养棉产业的区域特定适应策略提供了重要的见解。
