Application of combined fertilizers to improve growth, yield and essential oil composition of basil (Ocimum basilicum L.)

Basil (Ocimum basilicum L.) is a vital aromatic crop widely utilized in culinary and fragrance industries. The present study was conducted to implement a two-year field experiment (2019 and 2020) aimed to assess the impact of various fertilizers on the growth, yield, and essential oil composition of basil cultivated in Thanh Hoa Province, Vietnam. The fertilizer treatments included: no fertilizer (control), chemical fertilizer (NPK at 90-120-90 kg/ha), cow manure, chicken manure, and a combination of chemical fertilizer, cow manure, and chicken manure. The application of fertilizers resulted in significant improvements across various parameters compared to the control group. Basil plants treated with fertilizers exhibited increased height, la teral stem count, fresh and dry yields, chlorophyll and carotenoid content, essential oil yield, and essential oil content. The essential oil extracted from basil contained notable volatile compounds, with methyl chavicol, linalool, β-elemene, and epi-α-cadinol identified as the major constituents. The proportions of these compounds varied among the fertilizer treatments. Notably, the combined fertilization approach involving chemical fertilizers, cow manure, and chicken manure emerged as the most effective and significant in promoting basil growth and essential oil production. These findings not only contribute to the optimization of basil cultivation practices but also provide insights for the agricultural community, emphasizing the importance of balanced fertilization for maximizing the quality and yield of basil essential oil in the Vietnamese context.