1. Human land uses, such as agriculture, can leave long‐lasting legacies as ecosystems recover. As a consequence, active restoration may be necessary to overcome land‐use legacies; however, few studies have evaluated the joint effects of agricultural history and restoration on ecological communities. Those that have studied this joint effect have largely focused on plants and ignored other communities, such as soil microbes.
2. We conducted a large‐scale experiment to understand how agricultural history and restoration tree thinning affect soil bacterial and fungal communities within longleaf pine savannas of the southern United States. This experiment contained 64 pairs of remnant (no history of tillage agriculture) and post‐agricultural (reforested following abandonment from tillage agriculture >60 years prior) longleaf pine savanna plots. Plots were each 1 ha and arranged into 27 blocks to minimize land‐use decision‐making biases. We experimentally restored half of the remnant and post‐agricultural plots by thinning trees to reinstate open‐canopy savanna conditions and collected soils from all plots five growing seasons after tree thinning. We then evaluated soil bacterial and fungal communities using metabarcoding.
3. Agricultural history increased bacterial diversity but decreased fungal diversity, while restoration increased both bacterial and fungal diversity. Both bacterial and fungal richness were correlated with a range of environmental variables including above‐ground variables like leaf litter and plant diversity, and below‐ground variables such as soil nutrients, pH and organic matter, many of which were also impacted by agricultural history and restoration.
4. Fungal and bacterial community compositions were shaped by restoration and agricultural history resulting in four distinct communities across the four treatment combinations.
5. Synthesis and applications. Past agricultural land use has left persistent legacies on soil microbial biodiversity, even over half a century after agricultural abandonment and after intensive restoration activities. The impacts of these changes on soil microbe biodiversity could influence native plant establishment, plant productivity and other aspects of ecosystem functioning following agricultural abandonment and during restoration.

中文翻译：

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农业土地利用历史和恢复影响土壤微生物多样性

1. 随着生态系统的恢复，诸如农业等人类土地利用可能会留下长期的遗产。因此，可能需要积极恢复以克服土地利用的遗留问题；但是，很少有研究评估农业历史和恢复对生态群落的共同影响。研究这种共同作用的人主要集中在植物上，而忽略了其他群落，例如土壤微生物。
2. 我们进行了一项大规模实验，以了解农业历史和恢复树木稀疏对美国南部长叶松树大草原内土壤细菌和真菌群落的影响。该实验包含64对残余物（无耕作农业历史）和后农业（长于60年以前的耕作农业放弃种植后的重新造林）长叶松树热带稀树草原。每块土地面积为1公顷，分成27个块，以最大程度减少土地利用决策的偏见。我们通过稀疏树木来恢复半开放的大草原条件，并通过实验恢复了一半的残余和农业后的土地，并在树木稀疏后的五个生长季节从所有土地上收集了土壤。然后，我们使用metabarcoding评估了土壤细菌和真菌群落。
3. 农业历史增加了细菌的多样性，但减少了真菌的多样性，而恢复则增加了细菌和真菌的多样性。细菌和真菌的丰富度都与一系列环境变量相关，包括地上的变量，如枯枝落叶和植物多样性，以及地下的变量，如土壤养分，pH和有机质，其中许多也受到农业历史和自然环境的影响。恢复。
4. 真菌和细菌群落组成受恢复和农业历史的影响而形成，在四种治疗组合中形成四个不同的群落。
5. 综合与应用。在过去的半个世纪以来，放弃农业并进行了密集的恢复活动后，过去的农业土地使用都给土壤微生物多样性留下了持久的遗产。这些变化对土壤微生物生物多样性的影响可能会影响当地植物的建立，植物的生产力以及农业废弃后和恢复期间生态系统功能的其他方面。