Response of black cumin (Nigella sativa L.) plants to the addition of natural fertilizers and the inoculation by bacteria mix and seaweed liquid extract

This experiment was carried out duringthe two successive seasons of 2017/2018 and 2018/2019 aiming to study the effect of natural fertilizers namely mixed minerals ores; control, 200, 400 and 600 Kg/fed. (fed. = feddan = 0.420 hectares = 1.037 acres) and half recommended dose of NPK fertilizers and the inoculation of mixed of bacteria namely (Azotobacter chroococcum, Bacillus megatherium var Phosphaticum and Bacillus circulans) alone or with seaweed liquid extract , as well as, their interactions on vegetative growth, yield, fixed oil (percentage & yield) and fixed oil components of black cumin (Nigella sativa L.) plants. The highest values of all parameters were observed when the plants received the high rate of mixed minerals ores (600 kg /fed.). In regard to the inoculation with bacteria alone or with seaweed liquid extract, it was noticed that all treatments led to a significant increase in plant height, branch number, shoot dry weight, capsules number, seed yield , fixed oil (percentage & yield). The highest values of these previous characters were obtained when the inoculation with bacteria plus seaweed liquid extract. Generally, the combined effect among mixed minerals ores, the inoculation with bacteria and seaweed liquid extract treatments on Nigella sativa L., plants parameters was statistically significant. In most cases, the addition of the high rate of mixed minerals ores (600 kg /fed.) plus the inoculation with bacteria plus seaweed liquid extract was the most effective treatment in increasing these parameters. Results of GC-MS analysis of fixed oil revealed that the main fatty acids offered were myristic acid, palmatic acid, stearic acid, oleic acid, linoleic acid, linolenic acid and arachidic acid. The elevated percentages between the previous components were oleic acid followed by Stearic acid and arachidic acid. The treatments of mixed mineral ores and the inoculation with bacteria with seaweed liquid extract increased the former fatty acids in the fixed oil paralleled to untreated control.