Effect of N and Zn on ^|^lsquo;Hamlin^|^rsquo; sweet orange (Citrus sinensis Osbeck)

Effects of four nitrogen doses, i. e. 0, 500, 1000 and 1500g/tree and zinc sprays (0.6% ZnSO4) viz. water spray, spray in February, spray in April and spray in February and April on fruit yield, quality and leaf composition of‘Hamlin’sweet orange were investigated. Growth parameters in terms of girth, height and spread were not affected significantly by N, Zn or their combinations. Significant increase in the yield of fruits by N and Zn treatments was recorded.Fruit weight and diameter were significantly decreased by N application, whereas they were improved by zinc spray. Percentages of juice and T. S. S. were significantly increased by N application alone. The percentage of acidity, reducing sugars and T.S.S./acid ratio were not significantly affected by N, Zn and their combinations.Significant increase in N content and reduction in Zn content of leaves due to N application were observed. Spray of zinc in April or in February and April increased foliar zinc content. No significant variation of P and K contents of leaves was observed due to N, Zn or their combinations.