Abstract:【Objective】 Based on a long-term (26 years) fertilization field experiment in Qiyang, Hunan, China, investigations were made of influeces of long-term fertilization on Fenton-like reaction and soil C storage in red soil, with the aid of the techniques of high-performance liquid chromatography (HPLC), high flux sequencing, Synchrotron radiation Infrared microscopic imaging, X-ray photoelectron spectroscopy and in-situ microcosm incubation in soil pores varying in size (1 000 μm, 20 μm and 0.45 μm). 【Method】HO ? was trapped by terephthalic acid (TPA) (non-fluorescent), of which fluorescent product, i.e., 2-hydroxylterephthalic acid (HTPA), was determined with a high-performance liquid chromatographer (HPLC); Soil H2O2 quantified by a modified Fe2+-xylenol orange assay; Structure of bacterial communities and diversity analyzed with 16S ribosomal deoxyribonucleic acid (rDNA) gene sequencing, and interfacial processes identified with synchrotron radiation infrared microscopic imaging and X-ray photoelectron spectroscopy (XPS). In the microcosm incubation experiment, Polyvinylchlorid (PVC) cylinders were used and covered with a replaceable 0.45, 20, or 1 000 μm mesh fabric panel separately that allowed nothing but microorganisms and/ or roots to grow into the test cylinders. 【Results】Concentrations of H2O2, HO ? and Fe(II) were higher in Treatment M than in Treatment NPK, indicating that root excreta and microbes involved in regulating the concentrations. Meanwhile, a linear relationship between H2O2 and HO ? was found. H2O2 buffering capability was higher in Treatment M than in Treatment NPK, suggesting that the soil under long-term application of NPK degraded due to depletion of soil organic matter. Besides, the richness and diversity of soil microbes were significantly higher in Treatment M than in Treatment NPK. Furthermore, the effects of plant roots and microorganisms on soil bacterial community structure were lower in Treatment M than in Treatment NPK. In Treatment M soil bacterial communities affected the release of soil pH, DOC, soluble Fe and CO2, while in Treatment NPK they induced Fenton reactions through production of H2O2 and reduced Fe(II). On root-soil interface, distribution of clay minerals (3 619 cm-1), aliphatic C (2 914 cm-1), carboxylic C (1 725 cm-1) and hydroxyl C (1 135 cm-1) varied sharply in pattern, and the presence of roots increased the proportion of Fe(II) on the interface. 【Conclusion】These findings suggest that long-term manure inputs to soil initializes free-radical reaction by activating microbial communities and mobilizing iron, which is conducive to soil C stabilization and storage by increasing recalcitrance and interactions of SOC. In addition, microbe-mediated Fenton-like reaction may affect C storage and soil fertility.