Effect of Aqueous extract of Ulva fasciata and Cheatomorpha antennina of Green macro algae species as bio fertilizers on growth and Product of onion plant (Allium cepa L)

Abstract

A pot experiment was conducted at the nursery of the Faculty of Science, Hadhramout University, from July 2024 to March 2025, to evaluate the effectiveness of foliar application of aqueous extracts from two green algae species (Ulva fasciata and Chaetomorpha antennina) as bio-fertilizers in improving the growth and yield indicators of onion (Allium cepa L.). The study employed a Randomized Complete Block Design (RCBD) to test the effects of four different concentrations of the algal extracts: (0, 2, 4, and 6 g/L) The parameters studied included vegetative growth traits (plant height, number of leaves, leaf area, and dry matter) and yield characteristics (bulb diameter, weight, and height). The results revealed that Ulva fasciata significantly outperformed the other species in most studied traits, including plant height, number of tubular leaves, dry matter percentage, as well as bulb diameter and weight. In contrast, Chaetomorpha antennina did not record any significant superiority in the tested traits. Regarding concentrations, the (2 g/L) treatment achieved the best significant results for leaf area, bulb diameter, height, and weight. The (4 g/L) concentration was significantly superior in terms of the number of tubular leaves. Interestingly, the control treatment (0 g/L) recorded superior values for plant height and dry matter percentage, while the high concentration (6 g/L) did not show any significant superiority in any of the studied traits.