Characterization of Dissolved Organic Matter Components of Agricultural Waste Sources in Water Bodies Based on EEMs

Abstract

This study aimed to investigate the characteristics and contribution of dissolved organic matter (DOM) components released from agricultural waste to water and to control the exogenous input of DOM in the water environment. The EEMs-PARAFAC (three-dimensional fluorescence-parallel factor) method was used to analyse the grass surrounding Anfeng Pond. The extracts of stems, rice straws, and fallen leaves were used to extract DOM in the agricultural waste for analysis. The results showed that three components were separated from the grass stems, rice straws, and leaves, which were C1-type tryptophan, C2 visible-light region (fulvic acid-like), and C3-like humic acid (humic acid-like) components. Among them, the DOM of the leaf leachate mainly contributed the C2 visible light region (fulvic acid-like) components to the water body, and the DOM of the leaching solution of the grass stems and rice straw mainly contributed the C1-like tryptophan and C3-like humic acid components to the water body. Through principal component analysis, the DOM components of the grass stem and rice straw extracts showed similar characteristics; C1 and FI showed a significant (p<0.05) positive correlation, while C2 and C3 showed a very significant (p<0.01) positive correlation with FI and HIX index, respectively. The three components were significantly positively correlated with NO 3 -N. C3 was significantly positively correlated with NH 4 + -N. The management measures of agricultural wastes should be strengthened to reduce the transport of DOM produced by agricultural wastes to the water environment way.