Climate warming increases the frequencies of drought and excessive precipitation, and the influencing mechanisms and magnitudes of these extreme events on the water and carbon cycles of different crops still remain unclear. In this study, single-point simulations for six irrigated and rain-fed crops and global simulation were combined to comprehensively investigate the impacts of drought and excessive precipitation on evapotranspiration (ET), irrigation, net ecosystem exchange (NEE), and yields of crops. Results illustrated that the AgroIBIS-based CLM5 simulated ET and NEE dynamics well for rice, corn, winter wheat, soybeans, sugar beets, and potatoes after parameter optimization. The impacts of abnormal precipitation on ET, NEE, and crop yield were larger at rain-fed sites than at irrigated sites. The influencing magnitudes of precipitation shortage on ET depended on the occurring time of drought events relative to the growth stages of crops. Precipitation shortage (excessive precipitation) reduced (increased) ET and net carbon uptake by 4%–19% (4%–7%) and 3%–15% (1%–6%) compared to normal precipitation years at irrigated sites, while corresponding decrease (increase) was 7%–35% (24%–27%) and 19%–48% (12%–34%) at rain-fed sites. The proportional influencing magnitudes of precipitation shortage on ET, NEE, and yield increased sequentially for rain-fed crops. At the global scale, the simulated theoretical irrigation in extremely dry years was 25%–75% larger than that in normal precipitation years, and the actual irrigation was 3.5–4.0 times as large as the simulated theoretical value at irrigated sites, implying that drought intensified water resource shortage through excessive irrigation besides precipitation shortage.

中文翻译：

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极端事件对农田生态系统水和碳循环的影响：结合场地和全球建模的综合探索

气候变暖增加了干旱和降水过多的频率，这些极端事件对不同作物水碳循环的影响机制和程度尚不清楚。本研究将六种灌溉和雨养作物的单点模拟与全球模拟相结合，综合研究干旱和过度降水对蒸发蒸腾（ET）、灌溉、净生态系统交换（NEE）和作物产量的影响。 . 结果表明，基于 AgroIBIS 的 CLM5 在参数优化后很好地模拟了水稻、玉米、冬小麦、大豆、甜菜和马铃薯的 ET 和 NEE 动态。降水异常对 ET、NEE 和作物产量的影响在雨养场地大于灌溉场地。降水短缺对ET的影响程度取决于干旱事件相对于作物生长阶段的发生时间。与灌溉地点的正常降水年相比，降水短缺（过度降水）使 ET 和净碳吸收减少（增加）4%–19% (4%–7%) 和 3%–15% (1%–6%)，而在雨养地点相应的减少（增加）为 7%–35% (24%–27%) 和 19%–48% (12%–34%)。对于雨养作物，降水短缺对 ET、NEE 和产量的比例影响程度依次增加。在全球范围内，极端干旱年模拟理论灌溉量比正常降水年增加25%~75%，实际灌溉量是灌区模拟理论值的3.5~4.0倍，