Mineral Composition of Lettuce Grown in Hydroponic System With Wastewater

The use of treated effluents is not a new practice in agriculture, however, the optimization of wastewater was given with mineral fertilizers to grow lettuce in a hydroponic system, subject that is still barely studied. The objective of this study was to evaluate the mineral composition of three lettuce cultivars (Verônica, Vanda and Thais) in a hydroponic system using wastewater, well water and optimized nutrient solutions. The plants was grown in seven nutrient solutions, as S1 = Furlani solution; S2 = domestic wastewater; S3 = optimized domestic wastewater; S4 = well water; S5 = optimized well water; S6 = wastewater UASB and S7 = optimized UASB wastewater and the sub-plot for three lettuce cultivars. It was verified that the treatments S2, S4 and S6 when compared with the respective optimized solutions S3, S5 and S7 presented lower levels of nitrogen, potassium, calcium, zinc, copper and manganese in the two experiments. Same behavior was not observed for phosphorus and sodium. As for the cultivars, they presented, regardless of the experiment, mineral composition similar to each other when the same nutrient solution was used.