Abstract: A pot experiment was conducted to study the effects of irrigation with regenerated water on the growth, nutrient uptake, and quality of alfalfa. Four
treatments were installed, i.e., irrigation with fresh water (Q), irrigation with regenerated water (Z), mixed irrigation with regenerated water and fresh water (Z+Q), and rotational irrigation with regenerated water and fresh water (Z/Q). Comparing with treatment Q, treatment Z increased the stem length, lateral branch number, and plant biomass significantly, but decreased leaf area. Treatments Z, Z+Q, and Z/Q increased plant soluble protein content by 78.43%, 83.68% and 72.53%, respectively, but treatment Z decreased plant soluble sugar content. Treatment Z increased plant Ca and Mg contents by 27.78% and 26.61%, and treatments Z and Z+Q decreased plant Fe content by 28.71% and 10.09%, respectively. Treatments Z, Z+Q, and Z/Q increased the cadmium content in aboveground part of alfalfa by 98.6%, 89.5%, and 59.0%, respectively, but the cadmium and lead contents were still lower than the thresholds of National Sanitation Standard (GB 13078-2001). It was suggested that regenerated water could be used as a source of irrigation water in alfalfa growth, but its longterm effect should be concerned.

Key words: irrigation with regenerated water, alfalfa growth, quality, pot experiment, ecosystem ecology, ecological restoration, multi-objective planning, wetlands, Jilin Province.