Superiority of Organic Calcium Fertilizers over Inorganic Counterparts in Enhancing Fruit Firmness and Quality of Blue Honeysuckle (

Blue honeysuckle is an emerging small berry with high nutritional value; However, the soft texture of its fresh fruit leads to poor storability and transportability, severely limiting its economic returns. Calcium is a key element in maintaining the structural integrity of plant cell walls and membranes, and plays a decisive role in fruit firmness and postharvest quality. To elucidate the effects of different calcium fertilizers on the fruit firmness, yield, and fruit quality of blue honeysuckle, a two-year field experiment was conducted using foliar application of 2 L of calcium fertilizer (CaC, CaA, CaL, SAC and AAC) at a concentration of 1 mg/L, with the control receiving an equal volume of water. The results showed that sugar alcohol calcium had the best effect on fruit firmness, fresh weight, yield, solid-acid ratio, total anthocyanins, and ascorbic acid, significantly improving yield and quality. Amino acid calcium was most effective in increasing fruit volume and fruit number per plant. Calcium acetate and calcium lactate showed balanced improvements across indicators. Calcium chloride significantly enhanced fruit shape index, total phenols, and total flavonoids. These findings elucidate the specific effects of various treatments on key fruit traits, providing a theoretical basis for precision cultivation and quality regulation, thereby facilitating the standardization and high-quality development of the industry.