Aiming to evaluate the effect of nutrients balance in lettuce tip burn incidence, an experiment was carried out in Brasília, Brazil, from October 2001 until June 2002, in two phases. During the first phase four solution concentrations (0.5; 1.5; 2.5 and 4.0 mS.cm-1) were evaluated to determine the concentration with the highest percentage of tip burn. During the second phase, a solution concentration of 4,0 mS.cm-1 and foliar applications of three calcium sources (CaCl2, CaB2® and CaNO3) were applied to plants to prevent tip burn. Nutritive solution proposed by Castellane and Araújo in 1995 was used in both phases. The evaluated parameters were percentage of plants with tip burn incidence, leaf nutrient concentration and plant fresh weight. In the first trial the more concentrated (4,0 mS.cm-1) and the less concentrated (0,5 mS.cm-1) nutritive solution presented the highest percentage of plants with the symptoms. In the second trial, the zinc deficiency induced by boron high concentration, was responsible for the symptoms. This was the reason why calcium leaf application was not effective on reducing foliar symptoms.
Lactuca sativa L.; DRIS; leaf nutrients analysis; nutritional balance; production
