The effects of organic and conventional fertilization on oregano (Origanum onites L.) yield and quality factors

Oregano (Origanum onites L.) is an important medicinal and aromatic plant. The use of sector and economic value of oregano are determined by quality in world trade. This study was conducted during 2019–2021 to determine the effects of chemical and organic fertilizers on yield and quality of O. onites L. The experiment followed a randomized complete block design with six treatments and four replications, i.e., control (C: untreated plants), chemical fertilizer (F) (150:90:100 kg · ha⁻¹), farmyard manure (FYM), chicken manure (CM), vermicompost (VC) and spent mushroom compost (SMC) (the objective was to obtain 150 kg N · ha⁻¹ for organic fertilizer). Fresh yield increased by 3.36%–11.44% and 5.61%–13.59% with organic fertilization as compared with the control in both years while it increased by 22% and 19.0% with chemical fertilization. FYM and SMC were more effective in fresh yield among organic fertilizers. Essential oil (EO) increased by 18.8%–50.1% and 2.94%–19.85% with fertilization as compared with the control in both years. EO yield was significantly increased by fertilization, and CM was in the lead with direct effect, while VC and FYM had residual effects. The applications increased the carvacrol and thymol content of the EO compared with the control. VC was the most effective application for total flavonoid content, antioxidant activity and plant nutritional status, especially for nitrogen, phosphorus, potassium and calcium concentrations. The results showed that chemical and organic fertilizers positively affected the yield, EO content and nutritional status of O. onites.