Microbially derived inputs to soil organic matter: are current estimates too low?
Microbially derived inputs to soil organic matter: are current estimates too low?
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DOI：
10.1021/es071217x
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发表时间：
2007-10
影响因子：
11.4
通讯作者：
A. Simpson;M. Simpson;E. Smith;B. Kelleher
中科院分区：
文献类型：
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作者：
A. Simpson;M. Simpson;E. Smith;B. Kelleher
土壤微生物是许多土壤过程的核心，但由于土壤有机质的结构复杂性，准确量化微生物生物量的贡献仍然是一个重大的分析挑战。在这项研究中，对一系列土壤中的微生物进行了培养，以便将它们的分子图谱与土壤有机质和天然植被的分子图谱进行比较。利用现代核磁共振波谱，可以识别土壤有机质中微生物种类的贡献，并将其量化。在这些研究的基础上，微生物生物量对土壤有机质的贡献似乎比其他研究人员报道的1-5%要高得多。在一些土壤中，微生物生物量贡献了土壤可提取有机质组分的50%和胡敏素组分的约45%，并占土壤氮素的80%。这些发现意义重大，因为有机质与土壤中养分的释放和运输、氮素周转率、污染物的去向、土壤质量和肥力密切相关。因此，如果在某些情况下，土壤有机质和土壤有机氮主要来自微生物，那么这一部分，无论是以保存材料的形式还是以活细胞的形式，很可能在几个土壤过程中发挥着被低估的作用。
Soil microbes are central to many soil processes, but due to the structural complexity of soil organic matter, the accurate quantification of microbial biomass contributions continues to pose a significant analytical challenge. In this study, microbes from a range of soils were cultured such that their molecular profile could be compared to that of soil organic matter and native vegetation. With the use of modern NMR spectroscopy, the contributions from microbial species can be discerned in soil organic matter and quantified. On the basis of these studies, the contributions of microbial biomass to soil organic matter appear to be much higher than the 1-5% reported by other researchers. In some soils, microbial biomass was found to contribute >50% of the extractable soil organic matter fractions and approximately 45% of the humin fraction and accounted for >80% of the soil nitrogen. These findings are significant because organic matter is intimately linked to nutrient release and transport in soils, nitrogen turnover rates, contaminant fate, soil quality, and fertility. Therefore, if in some cases soil organic matter and soil organic nitrogen are predominately of microbial origin, it is likely that this fraction, whether in the form of preserved material or living cells, plays an underestimated role in several soil processes.