Yield of temperate forage grassland species is either largely resistant or resilient to experimental summer drought

Due to climate change, an increasing frequency and severity of drought events are expected to impair grassland productivity, particularly of intensively managed temperate grasslands.
To assess drought impacts, a common field experiment to manipulate precipitation was set up at three sites (two Swiss and one Irish) using monocultures and mixtures with two and four key forage species. Species differed in their functional traits: a shallow-rooted non-legume (Lolium perenne L.), a deep-rooted non-legume (Cichorium intybus L.), a shallow-rooted legume (Trifolium repens L.) and a deep-rooted legume (Trifolium pratense L.). A nine-week summer drought was simulated and soil water status and above-ground biomass yield were compared to a rainfed control.
Based on soil water measurements, the drought induced severe stress at both Swiss sites and extreme stress at the Irish site. Under severe drought, the legumes were more drought-resistant and showed an average change in above-ground biomass (CA...

受气候变化影响，干旱事件的发生频率与严重程度持续攀升，预计将损害草地生产力，尤其是集约化管理的温带草地。
为评估干旱的影响，研究人员在三处试验点（两处位于瑞士、一处位于爱尔兰）搭建了常见的降水调控野外实验，实验设置了单播种植以及包含2种、4种关键饲用植物的混播种植模式。供试物种的功能性状存在显著差异：包括浅根非豆科植物（Lolium perenne L.，即多年生黑麦草）、深根非豆科植物（Cichorium intybus L.，即菊苣）、浅根豆科植物（Trifolium repens L.，即白三叶）以及深根豆科植物（Trifolium pratense L.，即红三叶）。实验模拟了为期9周的夏季干旱，并将土壤水分状况与地上生物量产量与雨养对照组进行了对比。
基于土壤水分监测结果，干旱在两处瑞士试验点引发了重度水分胁迫，而在爱尔兰试验点则引发了极端水分胁迫。在重度干旱胁迫下，豆科植物的抗旱性更强，其地上生物量的平均变化量为（CA……