This study was carried out during three successive seasons of 2019, 2020 and 2021 on 25 years old Balady mandarin trees budded on sour orange root stock and planted at 5 x 5 m apart.
The selected trees grown at the experimental orchard of Faculty of Agriculture, Assiut University Egypt.  Where the soil has a clay texture and well-draining, surface irrigation was used.  Therefore, this study aimed to investigate the effect of seaweed extract, potassium and micronutrients on yield and fruit quality of Balady Mandarin trees.
Forty-eight healthy trees, uniform in vigor as possible were chosen. The chosen trees were divided into eight different treatments including the control. The selected trees received four sprays from each treatment at full bloom, just after fruit setting, first week of July and September.
Treatments were arranged in a randomized complete block design with three replications per treatment, two trees each. All the studied treatments significantly increased yield, fruit physical and chemical properties and decreased total acidity %. The best treatments during the three study seasons were spraying with potassium at 2% + micronutrients at 3% + seaweed extracts at 2%. According to the previous results, it could be concluded that spraying Balady mandarin trees with liquid potassium 2% + micronutrients 3% + seaweed extracts 2% four sprays at full bloom, just after fruit set, first week of July and September to measure yield and improve fruit quality.