Evaluating Bouteloua gracilis cultivars performance after drought, the role of the soil microbiome

After the Dust Bowl in the 1930s, it was common to reseed native grasses in areas impacted by the drought to help restore ecosystem structure and function. Given the forecasts of severe drought events, reseeding may need to be employed more frequently to enhance post-drought recovery. It is imperative to understand the adaptability of cultivars to the environmental conditions in which they are planted, including how they interact with the soil microbiome. Here, we used a common garden experiment with two cultivars of Bouteloua gracilis that were planted with soil microbial inocula extracted from either previously droughted or non-droughted soils. Our goal was to ex-amine whether the post-drought legacy of altered soil microbial communities affected the growth and performance of B. gracilis cultivars. We found no significant differences in relative growth rate or plant biomass, and minimal differences in the microbial community composition between the two cultivars. These results suggest that the post-drought legacy of altered soil microbial communities did not differentially affect growth and performance of the two B. gracilis cultivars evaluated, and that the growth of these cultivars did not differ in their effects on the soil bacterial communities found under ambient vs. previously droughted conditions.

20世纪30年代尘暴（Dust Bowl）事件发生后，在受干旱影响的区域补播本土草本植物以恢复生态系统结构与功能，是彼时常用的生态修复手段。鉴于当前极端干旱事件频发的预测趋势，为提升干旱后的生态恢复效率，补播措施的应用或需更为频繁。明确栽培品种对种植环境的适应性——包括其与土壤微生物组（soil microbiome）的互作模式——已成为亟需开展的研究方向。
本研究采用同质园试验（common garden experiment），以两种格兰马草（Bouteloua gracilis）栽培品种为试材，分别接种取自前期干旱土壤与非干旱土壤的土壤微生物接种剂。本试验旨在探究经干旱扰动的土壤微生物群落所产生的干旱遗留效应，是否会对格兰马草栽培品种的生长与表现产生影响。
研究结果表明，两种供试栽培品种的相对生长速率与植株生物量均无显著差异，其土壤微生物群落组成的差异也极小。上述结果提示：经干旱扰动的土壤微生物群落所产生的遗留效应，并未对两种供试格兰马草栽培品种的生长与表现产生差异化影响；同时，在自然环境与前期干旱环境下，这两种栽培品种对土壤细菌群落的调控效应也未表现出显著差异。