Comparative Effects of Organic and Mineral Calcium Sources on Yield, Nutritional Quality, and Postharvest Storage of Aubergine (Solanum melongena L.).

Aubergine is a horticultural crop valued for its nutritional quality, particularly its phenolic compounds, vitamins, and dietary fiber. However, its production is low due to poor fertilization management and the short shelf life of its fruits. This study aims to evaluate the effects of organic calcium fertilization with eggshell and beef bone powders compared with mineral calcium nitrate fertilization on aubergine yield, storage, and quality. The experimental design was a randomized block design with eight treatments consisting of two types of organic calcium sources for fertilization: eggshell powder and beef bone powder, each at two levels of application (30 g and 60 g per liter per plant); two levels of calcium nitrate application (10 g and 15 g per liter per plant), NPK 20-10-10 application at the level of 15 g per liter per plant, and the control treatment (0 g of fertilizer application), each treatment repeated three times. The results indicated that the highest fruit weight (386.11 ± 21.79 g), fruit girth (36.60 ± 1.94 cm), and net yield (66.64 ± 10.82 t/ha) were obtained with the control treatment, while the highest fruit number (7.40 ± 0.54 fruits) was obtained with bone powder_60g. The analysis of fruits during storage showed that treatments with eggshell powder (60 g) and calcium nitrate (15 g) extended the shelf life of fruits up to 30 days, whereas beef bone powder (30 g) resulted in the highest fruit loss rate. The analysis of the nutritional quality of the fruits at harvest showed that the treatments with eggshell powder significantly improved the contents of soluble sugars, polyphenols, proteins, and flavonoids compared to the plants treated with beef bone powder and the control. These findings indicate that eggshell powders can serve as alternative organic calcium sources to improve the nutritional quality and postharvest performance of aubergine fruit.