Conservation agriculture management practices (e.g., cover crops and residue retention) have been widely promoted to improve soil quality and environmental sustainability. However, little is known about the long-term interactive effects of cover crops and residue retention on yield of the cash crops and environmental outcomes in dryland cropping systems under climate change. We used the pre-validated APSIM model, driven by statistically downscaled daily climate data from 27 Global Climate Models (GCMs) under two Shared Socioeconomic Pathways (SSP245 and SSP585), to assess the combined influences of cowpea cover crops and three residue retention levels on soil water balance, soil organic carbon (SOC), nitrogen (N) dynamics, crop yield and gross margin across six crop rotation systems during the historical period (1985–2020), near future (2021–2056), and far future (2057–2092) in southeast Australia. Our results showed that, on average, cover crops decreased soil moisture on the day of sowing the succeeding cash crop (by 22%), but led to greater SOC stock (21%), reduced N loss through leaching (71%), and enhanced N uptake and yield of cereals, but decreased N uptake and yield of field pea. The effects of cover crops on yield and gross margin became more positive in the far future under both SSPs, which may be attributed to the SOC increase and greater N availability in the long term. These benefits were more evident under residue removal due to the partly compensatory effects from cover crop residues. Furthermore, cover crops were profitable in the wetter parts of the study region (east), but reduced gross margin in the drier west due to depletion of soil water reserves for the next cash crop. We conclude that particularly where residues are removed, the long-term adoption of cowpea cover crops could be a potential practice to sustain crop productivity with environmental co-benefits under climate change in the wetter parts of the dryland cropping region of southeast Australia.

保护性农业管理实践（例如，覆盖作物和残留物保留）已得到广泛推广，以改善土壤质量和环境可持续性。然而，关于覆盖作物和残留物保留对气候变化下旱地种植系统经济作物产量和环境结果的长期相互作用影响知之甚少。我们使用预先验证的 APSIM 模型，该模型由 27 个全球气候模型 (GCM) 在两个共享社会经济途径（SSP245 和 SSP585）下统计缩小的日常气候数据驱动，评估豇豆覆盖作物和三个残留物保留水平对气候变化的综合影响。土壤水分平衡、历史时期（1985-2020 年）、近期（2021-2056 年）和远期（2057-2092 年）六种作物轮作系统的土壤有机碳（SOC）、氮（N）动态、作物产量和毛利率在澳大利亚东南部。我们的结果表明，平均而言，覆盖作物在播种后续经济作物当天降低了土壤水分（22%），但导致更高的 SOC 存量（21%），减少了通过淋溶造成的 N 损失（71%），以及提高了谷物的吸氮量和产量，但降低了豌豆的吸氮量和产量。在两种 SSP 下，覆盖作物对产量和毛利率的影响在遥远的未来变得更加积极，这可能归因于 SOC 的增加和长期 N 可用性的提高。由于覆盖物的部分补偿作用，这些好处在去除残留物时更为明显作物残茬。此外，覆盖作物在研究区域（东部）较潮湿的地区有利可图，但由于下一个经济作物的土壤水储备耗尽，较干燥的西部地区的毛利率下降。我们的结论是，特别是在去除残留物的地方，长期采用豇豆覆盖作物可能是一种潜在的做法，可以在气候变化的情况下在澳大利亚东南部旱地种植区的湿润地区维持作物生产力和环境协同效益。