RESPONSE OF TWO BLACK CUMIN SPECIES TO FOLIAR ORGANIC FERTILIZATION UNDER SEMI-ARID CONDITIONS

Abstract

Black cumin is a member of the Ranunculaceae family, it is a popular herb called a miracle remedy to treat various diseases. A factorial experiment was conducted in RCBD with three replicates to evaluate the performance of Nigella spp. in response to foliar organic fertilizer (ALGAREN TWIN) in three concentrations (Control, 0.4 and 0.8 mL L-1). Seed yield and volatile oil bioactive composition across two consecutive seasons 2021-2022, and 2022-2023 were evaluated under semi-arid conditions with total precipitations of 310.5 and 715 mm respectively. The results of both seasons revealed a significant variation between the two species in most yield component traits. N. sativa showed the highest seed yield (737 kg ha-1), fixed oil (25%), and volatile oil (1.163%). The higher application rate of 0.8 mL L-1 generally leads to an increase in the yield of Nigella spp. seed and its components with 919 kg ha-1 seed yield, 26 % fixed oil, and 1.430% volatile oil. The interaction between N. sativa and 0.8 mL L-1 fertilization recorded a higher seed yield of 1065 kg ha-1, 28% fixed oil, and 1.430% volatile oil. The 2022-2023 season recorded a higher seed yield of 720 kg ha-1 than the first season. The analysis of volatile oils showed a mixture of phytochemical compounds. Terpenoid was the predominant constituent in both black cumin species. Thymoquinone was identified as a major constituent in N. sativa (25%). It could be concluded that the use of high rates of foliar organic fertilization on N. sativa gave a superior performance in most yield-related characters.