To elucidate the identity and mechanisms by which specific bacterial members drive efficient decomposition and utilisation of straw, the succession and co-occurrence patterns of ¹³C-labelled bacteria were analysed using DNA-stable isotope probing (SIP) techniques. Microcosms with ¹³C-labelled maize straw incorporated into soils subjected to no nitrogen (N) fertiliser (CK), chemical fertiliser (NPK) and chemical fertiliser with straw return (NPKS) treatments for 8 years were incubated for 360 days. The results showed that fertilisation regimes changed the ¹³C-labelled bacterial groups by abundance but not taxonomic composition, where N fertiliser application (NPK and NPKS treatments) reduced the relative abundance of maize straw carbon assimilators affiliated with Arthrobacter, Sphingomonas, Streptomyces, Burkholderia-Caballeronia-Paraburkholderia and Kribbella, but increased the relative abundance of Nocardioides, Rhodanobacter, Granulicella and Chujaibacter. Compared with CK and NPKS-treated soils, continuous inorganic fertilisation reduced the α-diversity of the ¹³C-labelled bacterial community and resulted in a loose and less competitive co-occurrence network of straw C-assimilators with more hubs needed to sustain its structural stability. Interestingly, straw return mitigated the negative effects of inorganic fertilisation by forming a tight and complex co-occurrence network of maize straw utilizers associated with NPKS-treated soils. Taken together, we emphasise the vital function of long-term straw return for sustaining soil biodiversity under intensive fertilised agricultural conditions and provide reference bacterial members for efficient straw utilisation.

中文翻译：

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连续8年秸秆还田减轻无机肥对碳循环土壤细菌的负面影响

为了阐明特定细菌成员驱动秸秆有效分解和利用的特性和机制，使用 DNA 稳定同位素探测 (SIP) 技术分析了¹³ C 标记细菌的演替和共生模式。^将13 C 标记的玉米秸秆掺入经过 8 年无氮 (N) 肥料 (CK)、化肥 (NPK) 和秸秆还田化肥 (NPKS) 处理的土壤中的微观世界培养 360 天。结果表明，施肥方式改变了¹³按丰度而非分类组成进行 C 标记的细菌群，其中施氮肥（NPK 和 NPKS 处理）降低了与节杆菌属、鞘氨醇单胞菌属、链霉菌属、伯克霍尔德菌属-Caballeronia-Paraburkholderia和Kribbella 相关的玉米秸秆碳同化菌的相对丰度，但增加了Nocardioides、Rhodanobacter、Granulicella和Chujaibacter的相对丰度。与 CK 和 NPKS 处理的土壤相比，连续无机施肥降低了¹³C 标记的细菌群落导致了一个松散且竞争较少的秸秆 C 同化器共现网络，需要更多的枢纽来维持其结构稳定性。有趣的是，秸秆还田通过形成与 NPKS 处理的土壤相关的紧密而复杂的玉米秸秆利用者共现网络，减轻了无机施肥的负面影响。综上所述，我们强调长期秸秆还田对于在集约化施肥农业条件下维持土壤生物多样性的重要作用，并为有效利用秸秆提供参考细菌成员。