Department of Earth and Environmental Sciences, Michigan State University, East Lansing, Michigan, United States of America.
W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, East Lansing, Michigan, United States of America.
PLoS One. 2020 Jan 28;15(1):e0225433. doi: 10.1371/journal.pone.0225433. eCollection 2020.
Climate change is likely to increase the frequency of drought and more extreme precipitation events. The objectives of this study were i) to assess the impact of extended drought followed by heavy precipitation events on yield and soil organic carbon (SOC) under historical and future climate, and ii) to evaluate the effectiveness of climate adaptation strategies (no-tillage and new cultivars) in mitigating impacts of increased frequencies of extreme events and warming. We used the validated SALUS crop model to simulate long-term maize and wheat yield and SOC changes of maize-soybean-wheat rotation cropping systems in the northern Midwest USA under conventional tillage and no-till for three climate change scenarios (one historical and two projected climates under the Representative Concentration Path (RCP) 4.5 and RCP6) and two precipitation changes (extreme precipitation occurring early or late season). Extended drought events caused additional yield reduction when they occurred later in the season (10-22% for maize and 5-13% for wheat) rather than in early season (5-17% for maize and 2-18% for wheat). We found maize grain yield declined under the projected climates, whereas wheat grain yield increased. No-tillage is able to reduce yield loss compared to conventional tillage and increased SOC levels (1.4-2.0 t/ha under the three climates), but could not reverse the adverse impact of climate change, unless early and new improved maize cultivars are introduced to increase yield and SOC under climate change. This study demonstrated the need to consider extreme weather events, particularly drought and extreme precipitation events, in climate impact assessment on crop yield and adaptation through no-tillage and new genetics reduces yield losses.
气候变化可能会增加干旱和更极端降水事件的频率。本研究的目的是：i）评估延长干旱后遭遇强降水事件对历史和未来气候下产量和土壤有机碳（SOC）的影响；ii）评估气候适应策略（免耕和新型品种）在减轻极端事件增加和变暖的影响方面的有效性。我们使用经过验证的 SALUS 作物模型，模拟了美国中西部北部地区常规耕作和免耕条件下玉米-大豆-小麦轮作系统在三种气候变化情景（历史情景和 RCP4.5 和 RCP6 下的两种预测情景）和两种降水变化（早季或晚季极端降水）下的长期玉米和小麦产量以及 SOC 变化。延长的干旱事件在季节后期发生时会导致额外的产量减少（玉米为 10-22%，小麦为 5-13%），而在季节早期发生时则减少较少（玉米为 5-17%，小麦为 2-18%）。我们发现，预测气候下的玉米籽粒产量下降，而小麦籽粒产量增加。与常规耕作相比，免耕能够减少产量损失并增加 SOC 水平（三种气候下为 1.4-2.0 吨/公顷），但无法扭转气候变化的不利影响，除非引入早季和新型改良玉米品种以提高产量和 SOC。本研究表明，在评估作物产量和适应气候变化的免耕和新型遗传学的气候变化影响时，需要考虑极端天气事件，特别是干旱和极端降水事件。
