Effect of Foliar Treatments with Calcium and Nitrogen on Oregano Yield

Oregano, Origanum vulgare L., is a perennial herbaceous plant belonging to the Lamiaceae family. Oregano shows variations in biomass yield and essential oil (EO) content due to the influence of abiotic and biotic factors. The aim of this study was to assess the effect of different foliar applications based on calcium (Ca) and nitrogen (N) on morphological and productive parameters in oregano. Tests were carried out in Sicily (Italy) in 2020–2021. In each year, eight foliar applications were applied. Only flowers and leaves were used for the extraction of the EO. For all parameters in the study, except for plant height and inflorescence length, the highest values were found in treated plants with respect to the control. In plants treated with calcium and nitrogen, an increase of between 0.6 and 1.6 t ha−1 was observed for fresh yield, and an increase of between 0.5 and 0.9 t ha−1 was observed for dry yield. The increase in biomass yield led to an increase in EO yield of between 4 and 12 kg ha−1. The results highlight that foliar treatments with Ca in combination with N enable growth in crop production in environments that show poor water availability.