Influence of Biochar and Irrigation Levels on Productivity of Marjoram (Origanum majorana L.) under Sandy Soil Conditions

A field experiment designed as a split-plot experiment based on a randomized complete block design with three replications was conducted during two summer successive seasons 2021 and 2022 at the Experimental Farm of EL-Quassasin Horticultural Research Station, Ismailia Governorate; Egypt, to investigate the influence of biochar at rates of 0, 2, 4, and 6 tons/fed. at three irrigation levels  (1, 1.5, and 2 hours/day) using a drip irrigation system on the growth, essential oil (productivity and constituents), as well as some chemical constituents of marjoram (Origanum majorana L.) plant grown in sandy soil. The obtained results revealed that both irrigation and biochar levels affected all the above-mentioned traits. It was clear that plant growth parameters increased as long as increasing irrigation levels and biochar rate. Considering the interaction, it was clear that generally the highest values in vegetative growth (plant height, number of branches, and herb fresh & dry weights/ plant), essential oil yield/plant, N%, and K% were attained from the treatment of irrigation at 1.5 hours/day combined with biochar at the rate of 6ton/fed. On the other hand, the highest values of essential oil%, essential oil components (p-cymene, trans-Sabinene hydrate, α-terpineol), as well as proline, were recorded in stressed plants (received 1h/ day irrigation and 0 biochar). The existing outcomes show that biochar application might increase water use efficiency and produce a high yield of marjoram. Subsequently, it could be a viable option to alleviate the severity effect of water deficit in marjoram growth, which opens opportunities for cultivating arid regions.