The Influence of Aerated Irrigation on the Evolution of Dissolved Organic Matter Based on Three-Dimensional Fluorescence Spectrum

Abstract

In order to unravel the effect of aerated irrigation on soil dissolved organic matter (DOM) fluorescence characteristics, and humification degree, a randomized block experiment was conducted with three factors and a two-level design, i.e., two irrigation rates (0.6 and 1.0 times of crop evaporation pan coefficient, W1 and W2), two nitrogen application rates (225 and 300 kg hm−2, N1 and N2), and two aeration rates (15% and 0% in control treatment, A1 and A0). Fluorescence regional integration (FRI) and correlation analysis methods were used to investigate the evolution characteristics of the soil DOM fluorescence spectrum. Under aerated and conventional subsurface irrigation, soil DOM components were dominated by humic acid-like substances, fulvic acid-like substances, tryptophan-like proteins, and supplemented by tyrosine-like proteins and dissolved microbial metabolites. Soil aeration could promote the consumption of soil DOM components under low irrigation rates and accelerate the consumption of soil DOM components under high irrigation rates. The humification index of AI treatments varied from 8.47 to 9.94 during the maturity growth stage of pepper, averagely increased by 31.59% compared with the non-aeration treatment. To sum up, aerated irrigation can promote the depletion of small molecular proteins and accelerate nutrient turnover and the accumulation of big molecular proteins.

Toxicity of Metal Oxides, Dyes, and Dissolved Organic Matter in Water: Implications for the Environment and Human Health

“…Synthetic dyes, known for their persistence, can alter the soil’s chemical composition, affecting nutrient availability and microbial activity [ 43 ]. Concurrently, dissolved organic matter, a complex mixture of organic compounds, interacts with metal oxides, potentially forming complexes that impact soil structure and nutrient cycling [ 44 , 45 ]. The interplay of these pollutants in irrigation water may trigger intricate reactions, influencing the overall soil environment.…”

Evaluation of Organic Matter Contribution Using Absorbance and Chromatographic Parameters in Lake Paldang, Republic of Korea

“…It is synthesized by photosynthetic organisms using light energy and represents the stored energy resulting from the conversion of solar energy into chemical energy [1,2]. Energy in an ecosystem is introduced as chemical energy, which circulates through the food chain and undergoes breakdown processes [3]. While increasing organic matter in a water system can enhance aquatic resource production, excessive or prolonged accumulation may promote underwater oxygen depletion [4], causing the death of aquatic animals, the formation of carcinogenic disinfection by-products during water purification, and increased water purification costs [5].…”