| The research was conducted to discover the relationship between water consumption and leaf area index (LAI), plant height, dry matter and underground biomass of alfalfa (Medicago sativa), to discuss the law of water consumption of alfalfa, and to analyze the effect of soil moisture and water consumption on the growth of alfalfa. The results showed that the critical water stage was seedling to branching period, and the most water consumption took place during branching to flowering stage when the growth speed was the fastest. During fruit-setting and maturing period, the water consumption decreased, the growth speed dropped and the leaf area index declined. The appropriate irrigation capacity for alfalfa in Hexi corridor was 580 mm. The study results may provide theoretical basis for alfalfa planting, water resource saving and increasing of water use efficiency. |