From the report “Influence of Spraying Some Biostimulants on Yield, Fruit Quality, Oil Fruit Content and Nutritional Status of Olive (Olea europaea L.) under Salinity”, of Adel M. Al‑Saif, Muhammad Moaaz Ali, Ahmed B. S. Ben Hifaa i Walid F. A. Mosa, published in Horticulturae, 2023.
The study evaluates the foliar application of two natural biostimulants—moringa leaf extract (MLE), rich in cytoquinins, and seaweed extract (SWE)—on Olea europaea cv. Kalamata grown under salinity stress.
The results show that both MLE and SWE, particularly at higher concentrations (6% and 3000 ppm), significantly enhanced leaf chlorophyll content, flower number and fruit set percentage in both seasons, clearly outperforming untreated trees. The combined treatments produced a synergistic effect.
Fruit quality traits—including fruit weight, size, length, diameter, pulp weight, firmness, pulp‑to‑fruit ratio, total soluble solids and oil content—were markedly improved by the biostimulant treatments, with the strongest effects again observed in the highest combination treatment. These improvements are attributed to enhanced photosynthetic activity, better pigment accumulation and improved physiological responses under salinity.
Finally, leaf mineral content (N, P, K, B, Zn, Fe, Mn) increased significantly in response to MLE and SWE. The authors conclude that combining MLE and SWE represents an eco‑friendly strategy to reduce reliance on chemical fertilizers and improve olive productivity under saline conditions.