The present investigation was carried out in two successive seasons of 2013 and 2014 on Keitt mango trees grown in sandy soil under drip irrigation system in National Research Centre, Researches and production Station, at El-Nobaria district, El-Behaira Governorate, Egypt. Trees were sprayed five times (one month intervals) with potassium nitrate at 0.0,1 and 2%, zinc sulfate at 200 ppm and boric acid at 200 ppm. Spraying started at March in the two seasons to study their effects upon growth, leaf mineral content, tree yield and fruit quality as well. Obtained results showed that, spraying Keitt mango trees five times with potassium nitrate at 2% combined with boric acid at 200ppm significantly increased number of branches/tree, branch diameter, number of leaves/branch, number of panicles/tree, number of retained fruits/tree, weight of fruit, fruit yield/tree and fruit quality parameters (i.e. TSS%, total sugars % and vitamin C), but it decreased fruit acidity. Whereas, using the low concentration of potassium nitrate (1%) combined with zinc sulfate at 200 ppm decreased the number of malformed panicles/trees. Moreover, using the combined treatment between potassium nitrate at 2% and zinc sulfate at 200 ppm improved shoot length (cm), leaf parameters )leaf area, fresh & dry weights and leaf chemical composition, as well. |
