Sources of fertilizers on the phytotechnical characteristics, oxidative stress and thymol production of Thymus vulgaris L.

The objective of this study was to assess the effects of different fertilizer sources on the phytotechnical characteristics, oxidative stress, and thymol production of Thymus vulgaris. The experiment was conducted in 3-dm³ pots containing soil:sand (2:1) + treatment (no fertilizer, organic fertilizer, or chemical fertilizer). The organic fertilizer was 8 kg m-2 of an equal mixture of bovine, goat, and quail manures. The variables assessed were leaf, stem, root, and total dry weights; chlorophyll and carotenoid contents; leaf nutrients; total polyphenols; total antioxidant capacity; oxygen radical absorption capacity; DPPH free radical scavenging activity; essential oil content; and thymol production, content, and yield. Organic fertilization significantly increased the variables assessed and reduced oxidative stress indicators. It resulted in gains in the dry weight of the plants and the accumulation of nutrients in dry leaves of T. vulgaris. For the quantitative parameters of the essential oil and thymol, organic fertilization was significantly higher than the other treatments, especially for thymol content and yield. T. vulgaris plants fertilized with organic fertilizer maximize their plant production and their yield of compounds of interest, such as thymol, possibly because these outputs indicate a balance between improved vegetative production and the elimination of reactive oxygen species.