Although mandarin is a non-climatic fruit, it quickly spoils during the post-harvest period. Foliar-applied nutrient solutions are very effective strategies to retain the quality and increase the storability of fruits. The current work evaluated the influences of foliar-applied potassium silicate, seaweed extract, fulvic acid, and two commercial fertilizers [CalfalB (containing calcium and boron) and Rice (containing macro- and micronutrients)] on the qualitative and physiochemical parameters of ‘Page’ mandarins in cold storage. Evaluation of the qualitative and physiochemical parameters was made on the day of harvest and after 15, 30, 45, and 60 days of storage. Foliar application of fertilizers was implemented as follows: the first was in mid-June and the other two were at intervals of 18 days. Compared to the control (non-fertilized trees), mandarins of fertilized trees showed considerably more levels of sensory characteristics, TSS (total soluble solids), TA (titratable acidity), firmness, carotenoid, vitamin C, total phenol, total antioxidant capacity, the activity of CAT (catalase), and GPX (guaiacol peroxidase), but lower levels of weight loss, TSS/TA, H2O2 (hydrogen peroxide), MDA (malondialdehyde), as well as pectin methylesterase and cellulase activity during the storage. The research results showed that foliar-applied potassium silicate, seaweed extract, fulvic acid, CalfalB, and Rice have the great potential to retain the quality features and increase the storability of mandarins in cold storage.
