A field experiment was conducted during the two successive seasons of 2019 and 2020 to elucidate the impact of compost as organic manure (0, 10, 20 and 30 m 3 /feddan) (feddan = 4200 m² = 0.420 hectares = 1.037 acres) and some stimulant substances namely (0, chitosan at 500, 1000 and 1500 ppm, amino acids at 100, 200 and 300 ppm and seaweeds extract at 1, 2 and 3 ml /l), as well as, their interactions on plant growth aspects (plant height, leaves dry weight /plant and per feddan and herb dry weight/ plant), pod yield /plant and per feddan, total anthraquinone glycosides percentage and total anthraquinone glycosides yield /plant and per feddan of Alexandrian senna ( Cassia acutifolia Delile) plants. The obtained results indicated that applying compost at all levels resulted a significant augment in all studied parameters, except for the low level (10 m³ /feddan) regarding plant height, leaves dry yield/plant and per feddan and herb dry weight/plant, in the first season. The most effective treatment in augmenting these traits was given by using compost at the high level (30 m³ /feddan). Foliar spray with the three examined stimulant substances, at all concentrations, led to a significant augment in all aspects, except for 500 ppm chitosan concerning leaves dry yield /plant and per feddan, In the second season, 500 ppm chitosan, 100 ppm amino acids and 1 m /l seaweeds extract, in the first season and, 100 ppm amino acids concerning total anthraquinone glycosides percentage, in the second season. Clearly, foliar spray with seaweeds extracts at 3 ml /l proved to be more effective in increasing the tested characteristics. Obviously, the interaction was statistically significant effect on all studied aspects. Utilizing compost at the high level (30 m³ /feddan) with seaweeds extract at 3 m /l gave the most effective treatment in augmenting these traits.
