Characterization of the Physicochemical Properties of Salix psammophila Sand Barriers Degradation Under Ultraviolet Irradiation and Synergistic Water Environment

The degradation of Salix psammophila mechanical sand barriers in desert environments can lead to a reduction in their windbreak and sand-fixing benefits, thereby becoming a significant factor limiting the operational lifespan of these structures. Targeting the typical damage types of S. psammophila sand barriers in the desert, we conducted simulations of desert sunlight and rainfall phenomena and investigated the changing characteristics of the physical, mechanical, and chemical properties of sand barriers in the degradation process. The results clearly indicate that (1) accelerated aging for 288 h represents a critical time point for assessing changes in physical, mechanical, and chemical properties during the interaction between ultraviolet irradiation and water. Following 576 h of accelerated aging, compared with a fresh S. psammophila branch sample (CK), the mass loss percentage was 24.33%, while the basic density decreased by 35.87%, and the modulus of rupture and elasticity decreases by 24.93% and 23.03%, respectively. (2) After accelerated aging for 576 h, the contents of lignin, hemicellulose, and cellulose decreased by 35.93%, 33.84%, and 22.38%, respectively. The interaction between simulated ultraviolet irradiation and water under sunlight intensifies the vigorous physical and chemical reactions occurring within the S. psammophila sand barrier, alters its internal structure, diminishes its mechanical properties, and expedites the degradation of its protective capabilities.