Effect of natural fertilization on the yield, biological value, and qualitative and quantitative composition of essential oil in common basil (<i>Ocimum basilicum</i> L.)

Basil (Ocimum basilicum L.) is one of the most popular herbal plants used globally in the food and pharmaceutical industries and as an ornamental plant. It is highly valued for the rich content of active substances, whose amount depends on environmental and anthropogenic factors. The type of fertilizer used is an important determinant of the yield and quality of the herb and the soil environment. The aim of the study was to assess the effect of natural fertilizers (granulated cattle manure and granulated chicken manure) applied at different doses (50, 100, 150, 200 g m⁻²) on the quantity and quality of the yield of common basil (Ocimum basilicum L.) cultivated in the temperate climate of Lublin Upland. The applied doses of manure had a significant effect on the fresh weight of O. basilicum L. A significant effect of the type and dose of manure on the content of L-ascorbic acid was found. Additionally, the fertilizer dose had a significant effect on the extract content in the analyzed plants. Significantly higher basil yields were achieved in the fertilization variant with 50 g m⁻² and 100 g m⁻² of the manure. The concentration of essential oil in the plants did not change under the influence of the applied manure dose. The experimental factors did not exert an effect on the content of essential oil with its main component (linalool), total nitrogen, and protein in basil plants. The highest content of linalool (78.22%) in the O. basilicum L. herb was determined in the variant with chicken manure fertilization at the dose of 150 g m².