arid area, alfalfa, artificially layered soil, photosynthetic characteristics, transpiration characteristics, Agriculture (General), S1-972, Irrigation engineering. Reclamation of wasteland. Drainage, TC801-978

【Objective】Stratifying soil with sand is an engineering technique commonly used to improve the drainage and aeration of fine-textured soils. This study investigates its effects on the growth, transpiration, and photosynthesis of alfalfa.【Method】A field experiment was conducted to compare intact soil (FUS) and soil treated with a sand-stratification technique (ALS). In each treatment, physiological traits, photosynthetic traits, transpiration, and water consumption of alfalfa were measured. The hydrothermal balance of each soil type was analyzed using the soil-heat-water model.【Result】Under identical conditions, ALS significantly influenced the physiological and ecological traits of alfalfa. Specifically, compared to FUS, ALS increased average plant height by 8.5%, stem diameter by 10.4%, stem-to-leaf ratio by 18.2%, and dry mass by 7.1%. Under natural conditions, ALS increased the daily average net photosynthetic rate by 8.69% to 109.39%, with maximum increases ranging from 9.27% to 64.23%. Moreover, ALS significantly enhanced transpiration and stomatal conductance compared to FUS. The total evapotranspiration of alfalfa was 576.85 mm under FUS and 381.45 mm under ALS. Additionally, ALS reduced soil-surface evaporation by 51.22% during the peak water-demand period of the growing season.【Conclusion】Stratifying fine-textured soil with sand improved water infiltration, reduced soil surface evaporation, and enhanced the water use efficiency of alfalfa, thereby increasing its yield.