Relationship Between PARAFAC-Derived Compositional Heterogeneity of Fluorescent Water-Soluble Soil Organic Matter and Soil-Structure Stability

摘要

Soil organic matter (SOM) is considered as an effective cementing agent that contributes to the stabilization of soil aggregates and structure [1,2]. However, there are also indications that under certain conditions SOM and especially humic substances (HS), which comprise a significant portion of SOM, can enhance clay dispersion and aggregate breakdown [3,4]. The opposing findings of the impact of SOM on aggregate stability could be related to the heterogeneity in the chemical composition of dissolved organic matter (DOM) in general, and that of dissolved HS in particular. Due to the DOM fluorescent properties, its compositional heterogeneity can be evaluated by 3D excitation emission fluorescence spectroscopy coupled with chemometric analysis (parallel factor analysis; PARAFAC) [5]). The objectives of this study were to characterize, with 3D fluorescence spectroscopy, the compositional heterogeneity of DOM and seek possible relationships between properties associated with soil structure and the composition of DOM.