Characteristics of Fluorescent Dissolved Organic Matter in Paddy Soil Amended With Crop Residues After Column (0–40 cm) Leaching

Dissolved organic matter (DOM) has a critical impact on various processes in the ecological environment, especially soil and surface water due to its mobility reactivity. In present study, column experiment simulating paddy field was conducted evaluate feasible application of inorganic fertilizer incorporated with three types materials (wheat straw, rapeseed shell, astragalus smicus). Researchers investigated vertical distinctions (combined different 0–10 cm) DOM 0–40 cm profiles after long-term leaching. Excitation–emission matrices coupled parallel factor analyses (EEM-PARAFAC) UV-visible techniques were employed diagnose spectral characteristics at four depths treatments, qualitatively quantitatively. The results showed that content CF (conventional fertilizer) (0.14 g kg −1 ) highest 10–20 layer CK (no (0.05 30–40 lowest, mean DOC concentration decreased increase depth. Four fluorescent components, protein tryptophan-like, humic acid-like, fulvic solubility-like microbial metabolite product materials, identified by PARAFAC model. Relative distributions calculated components suggested mainly contained more aromatic litter acid However, SUVA 254 maximum 20–30 layers, indicating strong abundant hydrophobic fractions. Fluorescent index (FI) values from treatments have similar terrestrial allochthonous source topsoil deeper soil. short, findings obtained our work could commendably provide some valuable optical information released offer technical guidance when applying or green during rice production.