https://doi.org/10.37229/fsa.fjh.2026.05.20

The study was carried out on three orange cultivars: Sweet, Olinda, and Valencia, grown at Balouza Research Station, North Sinai Governorate, Egypt, during 2024 and 2025 seasons. The objective was to evaluate the effect of nutrients on productivity and fruit quality of cultivars grown under North Sinai conditions. Seven spray treatments were tested: T1, control (water only); T2, Ca at 1.5 cm/L; T3, Ca at 3 ml/L; T4, K at 1.5 ml/L; T5, K at 3 ml/L; T6, Mo +B at 0.5 ml/L; and T7, Mo +B at 1 ml/L. The experiment was arranged in a split-plot design with three replications, where cultivars were assigned to the main plots and nutrient treatments to the sub-plots. The results revealed that nutrition significantly improved productivity and fruit quality compared with the control. Overall, spraying K at 3 cm/L generally gave the highest values for fruit yield per tree, fruit weight, fruit dimension, juice volume, and juice density. In addition, Mo +B at 1 ml/L and K at 3 ml/L were also the most effective treatments for improving juice percentage, properties, highest maturity index, and reducing juice acidity. Among the cultivars, Olinda exhibited the best performance in terms of yield and external fruit quality, whereas Valencia showed superior internal fruit quality, including properties. Sweet cultivar matured earlier than the other cultivars. Therefore, foliar spraying with K at 3 ml/L, Mo +B at 1 ml/L, or Ca at 1.5 ml/L is recommended for improving productivity, juice characteristics, and chemical quality under North Sinai conditions.