Aims

The application of cover crop residue is an important means in managing paddy soil. This study was to investigate the influences of minerals on the mineralization of organic matter and the community and necromass of microbes in paddy soils amended with cover crop residue.

Methods

¹³C-labelled cover crop residue (Astragalus sinicus L.) was prepared using a pulse labeling method. The mineralization of cover crop residue and native soil organic matter and the community and necromass of microbes in two flooded paddy soils amended with or without illite, goethite and ferrihydrite was investigated by incubation experiments. The released CO₂/CH₄ was analyzed by gas chromatography. Amino sugar was used as the biomarker of microbial residue carbon. Soil microbial communities were analyzed by high-throughput sequencing and quantitative polymerase chain reaction.

Results

Illite, goethite and ferrihydrite significantly decreased the amounts of both CO₂ and CH₄ emissions from native soil organic carbon in both paddy soils. Moreover, the inhibition efficiency followed the same sequence of ferrihydrite > goethite > illite for both CO₂ and CH₄ emissions. However, ferrihydrite significantly stimulated the mineralization of cover crop residue in both paddy soils. The examined minerals, especially ferrihydrite, also tended to decrease bacterial and fungal abundance and diversity in both paddy soils. Moreover, the contents of both bacterial and fungal residue carbon were significantly decreased by the examined minerals in alkaline paddy soil.

Conclusion

Examined minerals tended to decrease total mineralization of cover crop residue and native organic matter, the microbial abundance, diversity, and necromass in flooded paddy soils.

中文翻译：

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矿物质在调节覆盖作物残留物和原生有机质矿化以及淹水稻土中微生物群落和坏死物中的作用

目标

覆盖作物秸秆的施用是管理水稻土的重要手段。本研究旨在探讨矿物质对覆盖作物残茬改良水稻土中有机质矿化以及微生物群落和坏死物的影响。

方法

使用脉冲标记方法制备¹³ C标记的覆盖作物残渣（黄芪）。通过培养实验研究了两种经或未经伊利石、针铁矿和水铁矿改良的淹水稻土中覆盖作物残留物和原生土壤有机质的矿化以及微生物的群落和坏死物。通过气相色谱分析释放的CO ₂ /CH ₄ 。氨基糖被用作微生物残留碳的生物标志物。通过高通量测序和定量聚合酶链反应分析土壤微生物群落。

结果

伊利石、针铁矿和水铁矿显着降低了两种水稻土中原生土壤有机碳的CO ₂和CH _{4排放量。此外，对于CO 2}和CH ₄排放的抑制效率遵循相同的顺序：水铁矿>针铁矿>伊利石。然而，水铁矿显着刺激了两种水稻土中覆盖作物残留物的矿化。所检查的矿物质，尤其是水铁矿，也往往会降低两种稻田土壤中细菌和真菌的丰度和多样性。此外，碱性水稻土中所检测的矿物质显着降低了细菌和真菌残留碳的含量。

结论

所检查的矿物质往往会降低覆盖作物残留物和原生有机质的总矿化度、淹没稻田土壤中的微生物丰度、多样性和坏死物。