Effects of irrigation with regenerated water on the growth and quality of alfalfa

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.