Bioavailability Evaluation of Dissolved Organic Matter Derived from Compost-Amended Soils

In this study, hetero-two-dimensional correlation spectroscopy (hetero-2DCOS) combined with parallel factor analysis (PARAFAC) was employed to reveal the inner changes in the dissolved organic matter (DOM) components derived from soil amended with seven different composts. The dynamics of the four DOM components showed that the fluorescence peaks in each component varied in different directions during mineralization. Structural equation models (SEMs) demonstrated that the compost amendments changed the correlations of the total organic carbon (TOC), total nitrogen (TN), and bacterial community composition with DOM components and strengthened the cooperative function related to transformation of DOM components. The compost sources were further ranked as cabbage waste (CW) > chicken manure (CM), dairy cattle manure (DCM), tomato stem waste (TSW), peat (P) > municipal solid waste (MSW), sewage sludge (SS) by projection pursuit regression (PPR) analysis. It is helpful to improve the bioavailability of compost products to obtain composts with a particular function.