Production of Lettuce (Lactuca Saf/Va, L.) Under Effects of Irrigation with Treated Wastewater

摘要

The present work tells an experience of direct reuse of sewer treated at a stabilization pond in the cultivation of lettuce (Lactuca sativa, L), evaluating the influence of irrigation on the non destructive components of growth and on the vegetable production, with the application of wastewater and of addition of organic manuring. The experiment was conducted in the dependences of the Station of Treatment of Sewer of the municipal district of Campina Grande, belonging to the Company of Water and Sewer ofParaiba state, Brazil, in entirely randomized experimental design with four replications, being the factors two types of water (provisioning and wastewater treated by system of stabilization ponds) and the presence or not of bovine fertilizer. Two cycles of lettuce cultivation were performed and the results analyzed statistically; the first experiment was accomplished during the period from July to August of 2003 and the second one from October to November of 2003. Before the harvest of the lettuceplants of the useful area of the experimental plots, the measurements of the height and of the diameter of each plant were made. Soon afterwards, all the 14 lettuce plants were harvested, making latter the wash of them to remove the soil and then to proceed the counting of the number of leaves, measurements of the length and diameter of the root and the weighting of the aerial part and of the root, separately. The productivity (kg m-2) for each treatment was evaluated in the useful area of each plot. The largest values for the productivity and for the non destructive variables were found in the lettuces produced under irrigation with wastewater and organic manuring.