Microbes, as important regulators of ecosystem processes, play essential roles in ecosystem recovery after disturbances. However, it is not clear how soil microbial communities and functions change and affect forest recovery after clear-cutting. Here, we used metagenome sequencing to systematically analyse the differences in soil microbial community composition, functions, and nitrogen (N) cycling pathways between primary Korean pine forests (PF) and secondary broad-leaved forests (SF) formed after clear-cutting. Our results showed that the dominant phyla of the two forest types were consistent, but the relative abundance of some phyla was significantly different. Meanwhile, at the genus level, the fold-changes of rare genera were larger than the dominant and common genera. The genes related to microbial core metabolic functions, virulence factors, stress response, and defence were significantly enriched in SF. Additionally, based on the relative abundance of functional genes, a schema was proposed to analyse the differences in the whole N cycling processes between the two forest types. In PF, the stronger ammoniation and dissimilatory nitrate reduction (DNRA) and the weaker nitrification provided a genetic explanation for PF dominated by ammonium (NH₄⁺) rather than nitrate (NO₃⁻). In SF, the weaker DNRA, the stronger nitrification and denitrification, the higher soil available phosphorus (AP), and the lower nitrogen to phosphorus ratio (N/P) comprehensively suggested that SF was faced with a greater degree of N limitation. These results offer insights into the potential relationship between soil microbes and forest recovery, and aid in implementing proper forestry management.

中文翻译：

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土壤微生物对氮循环调控对森林恢复至高潮群落的影响

微生物作为生态系统过程的重要调节者，在干扰后的生态系统恢复中起着至关重要的作用。然而，目前尚不清楚土壤砍伐后土壤微生物群落和功能如何变化并影响森林恢复。在这里，我们使用了元基因组测序系统地分析了原始红松林（PF）和明确砍伐后形成的次生阔叶林（SF）之间的土壤微生物群落组成，功能和氮（N）循环路径的差异。我们的结果表明，两种森林类型的优势种是一致的，但是某些种的相对丰富度却存在显着差异。同时，在属水平上，稀有属的倍数变化大于优势属和普通属。与微生物核心代谢功能，毒力因子，应激反应和防御能力显着增强。此外，基于功能基因的相对丰度，提出了一种方案来分析两种森林类型之间整个N循环过程的差异。在PF中，氨化和异化硝酸盐还原作用（DNRA）越强，硝化作用越弱，这为氨（NH）为主的PF提供了遗传学解释。₄ ⁺），而不是硝酸盐（NO ₃ ^- ）。在SF中，DNRA越弱，硝化和反硝化作用越强，土壤有效磷（AP）越高，氮磷比（N / P）越低，表明SF面临更大的氮限制。这些结果提供了对土壤微生物与森林恢复之间潜在关系的见解，并有助于实施适当的林业管理。