Effect of Organic and Biofertilization on Growth, Yield, and Chemical Constituents of Black Cumin (Nigella sativa L.)

Abstract

The increasing global demand for high-quality medicinal plants, coupled with the environmental and health concerns associated with chemical fertilizers, has spurred a resurgence of interest in sustainable agricultural practices. The over-reliance on synthetic NPK fertilizers has led to soil degradation, groundwater pollution, and elevated production costs. In two consecutive seasons (2023/2024 and 2024/2025), this study assessed the impact of combined organic and biofertilization on Nigella sativa L. growth, seed output, oil productivity, and chemical composition under Egyptian conditions. A randomized complete block design was used to arrange twelve fertilization treatments that included chicken manure (PM; 10 and 20) m³ fed⁻¹, Nitrobein (NT) (Azospirillum sp.), Phosphorein (Ph) (Bacillus megatherium var. phosphaticum), and active dry yeast. When compared to the control, all fertilization treatments greatly increased vegetative growth and output. The maximum plant height (76.7 cm), number of capsules (45.06 plant⁻¹), seed weight (4.78 g plant⁻¹), and seed yield (0.76 t ha⁻¹) were all produced by the combined treatment Ph + PM (20 m³ fed⁻¹), which was 73% higher than the control (0.44 t ha⁻¹). Yeast + PM (20 m³ fed⁻¹) enhanced the fixed oil content from 19.91% (control) to 27.59%, while phosphorein treatment increased the volatile oil production from 0.013 to 0.038 mL plant⁻¹. Fertilization strategy also affected the content of fatty acids. The predominant unsaturated fatty acid, linoleic acid, varied from 66.25% to 83.09%, with yeast application showing the highest percentage. In addition to increasing nitrogen, phosphorus, and potassium accumulation in plant tissues, integrated treatments greatly increased chlorophyll a (1.43 mg g⁻¹ vs. 1.06 mg g⁻¹ in the control). Overall, the combination of biofertilizers and high-rate poultry manure outperformed individual treatments, increasing N. sativa oil quality and yield amount. These results demonstrate integrated nutrient management as a viable approach to raising black cumin productivity and phytochemical quality in semi-arid environments.