Abstract The pathways of exogenous carbon (C) mineralization and retention in soil have been widely investigated via analyses of microbial fingerprints (e.g., phospholipid fatty acids (PLFAs)) and footprints (e.g., amino sugars). However, the potential of soil resident microbiota to metabolize plant-derived substrates remains unclear. This study aimed to clarify how microbial growth cumulatively contributes to residual C transformation under different substrate qualities and soil management practices. Nonlinear fitting of the cumulative contribution of PLFA-based microbial growth to residual C decomposition showed that among microbial groups, fungi metabolized grains to the greatest extent, and gram-negative bacteria contributed the most to root C metabolism, whereas gram-positive bacteria and actinomycetes were generally less competent in the decomposition of all residues. The sequestration of leaf and root C in amino sugars was greater without tillage than with tillage, whereas an opposite tillage trend was observed for grain-derived galactosamine. Our findings highlight that the potential of fungi and bacteria for residual C transformation depends on residue quality. Furthermore, high-quality residue (e.g., grain) transformation is strongly exacerbated by soil disturbance, whereas few tillage-facilitated effects occur with a decline in substrate quality (e.g., leaf and root).

中文翻译：

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转化植物残留碳的微生物代谢潜力

摘要 通过微生物指纹（如磷脂脂肪酸（PLFA））和足迹（如氨基糖）的分析，外源碳（C）矿化和土壤保留的途径已得到广泛研究。然而，土壤常驻微生物群代谢植物来源底物的潜力仍不清楚。本研究旨在阐明在不同基质质量和土壤管理实践下微生物生长如何累积促进残留碳转化。基于PLFA的微生物生长对残留C分解的累积贡献的非线性拟合表明，在微生物群中，真菌代谢谷物的程度最大，革兰氏阴性菌对根C代谢的贡献最大，而革兰氏阳性菌和放线菌在分解所有残留物方面的能力通常较差。与耕作相比，未耕作的叶和根 C 在氨基糖中的螯合量更大，而对谷物衍生的半乳糖胺观察到相反的耕作趋势。我们的研究结果强调，真菌和细菌转化残留 C 的潜力取决于残留质量。此外，土壤扰动会严重加剧高质量残留物（例如谷物）的转化，而随着基质质量（例如，叶和根）的下降，几乎不会发生耕作促进效果。我们的研究结果强调，真菌和细菌转化残留 C 的潜力取决于残留质量。此外，土壤扰动会严重加剧高质量残留物（例如谷物）的转化，而随着基质质量（例如，叶和根）的下降，几乎不会发生耕作促进效果。我们的研究结果强调，真菌和细菌转化残留 C 的潜力取决于残留质量。此外，土壤扰动会严重加剧高质量残留物（例如谷物）的转化，而随着基质质量（例如，叶和根）的下降，几乎不会发生耕作促进效果。