Effects of intermittent cycle pulse sprinkler irrigation induced by solar-coupled compressed air energy storage on soil structure and infiltration characteristics

Traditional constant-pressure continuous sprinkler irrigation is characterized by high application intensity and excessive droplet kinetic energy, which can disrupt soil aggregates, promote surface crust formation, reduce infiltration capacity, and even trigger surface runoff. To address these challenges, this study developed an independently designed solar-coupled compressed air energy storage (CAES-SP) intermittent cyclic pulse sprinkler system. Using a 2D video disdrometer (2DVD) and X-ray micro-computed tomography (micro-CT), comparative experiments were conducted on loess soil under two irrigation regimes: continuous irrigation (CK: 8 mm/h for 3 h) and intermittent irrigation (T1-T3: 1–4 mm/h over 6–24 h), with a fixed total water volume of 24 mm. The objective was to investigate the effects of average sprinkler intensity (AR) and sprinkler precipitation kinetic energy (SP) on soil structure and infiltration dynamics. Results indicated no significant differences in droplet diameter, velocity or impact angle between irrigation modes. However, intermittent irrigation significantly enhanced soil physical properties: soil aggregate breakdown decreased by 3.97%-12.82%, porosity increased by 27.02%-53.51%, steady infiltration rate improved by 12.50%-67.75%, and cumulative infiltration exceeded that of CK by 45.21%-132.18%. Both steady and cumulative infiltration exhibited negative power-law relationships with AR and SP, whereas crust thickness and strength followed logarithmic relationships with AR and SP. This study elucidates the regulatory mechanisms of hydraulic parameters on soil microstructure and provides empirical models that support the optimization of CAES-SP irrigation systems, offering a foundation for efficient and environmentally sustainable irrigation practices in arid and semi-arid regions.