The main scope of this study was to compare the use of wastewater and surface reservoir water on the development of the lettuce (Lactuca sativa L.), cv "Elisa", during two crop cycles. The crop development was analyzed at the 13, 25, 33, 40 and 45 days after the transplanting in the 1st cycle and at the 14, 25, 33, 41 and 47 days in the 2nd cycle. The commercial classification and water use efficiency at the end of each cycle was evaluated, comparing the sprinkler, subsurface and surface drip irrigation systems. The highest value of dry mass, fresh mass and leaf area were found for the treated wastewater, although the plant height and the leaf number were not affected by its use and the yield in the two cycles was higher for the subsurface drip irrigation treatment, followed by the surface drip using wastewater. The highest value of the water use efficiency was obtained in the drip irrigation systems, using wastewater in both crop cycles; on the other hand, the largest percentage of plants, under wastewater or surface reservoir water treatments, were classified in classes 20 and 25 and 15 and 20, respectively, in both crop cycles. The best results for the crop development, commercial classification and water use efficiency were obtained for wastewater applied through drip irrigation systems.
reuse; sprinkler; commercial classification; water use efficiency; Lactuca sativa L
