Comparative analysis of plant morphometric traits, essential oil yield, and quality of Origanum majorana L. cultivated under diverse sustainable organic nutrient management strategies

Plant nutrition is one of the major factors affecting the production of medicinal plants. This study aimed to assess and compare plant morphometric characteristics, essential oil yield, and composition of Origanum majorana L. irrigated with water of different qualities at two cuts. The greenhouse experiment followed a randomized completely block design of three treatments (T1: water mixed with standard hydroponics solutions A and B, T2: Biofloc wastewater, and T3: aquaculture wastewater) with three replicates per treatment. The results of this study indicated that T1 significantly improved the plant morphometric characteristics, such as plant height, number of branches, fresh weight, and dry weight, compared to other treatments in cut 1 and cut 2. The results of the soil analysis showed that T1 had higher values for the soil bulk density, potassium content, and electroconductivity compared to other treatments. The total phenolic content was significantly higher in T2 than in T1 and T3 in both cuts. However, the essential oil yield in cut 2 was higher than that in cut 1 across all the treatments, with T1 recording higher values, followed by T2 and T3, respectively. The major essential oil constituents in all the treatments were 4-Terpineol (33.95% - 50.24%), γ-Terpinene (3.95% - 15.74%), α-Humulene (3.39% - 10.33%), α-Terpineol (3.72% - 8.37%), and Sabinene (2.16% - 6.31%). In cut 1, the percentage of the major essential oil constituents was in the order T1 > T2 > T3, versus cut 2, which was T3 > T1 > T2. In conclusion, irrigating Origanum majorana with hydroponic solutions enhances plant growth, essential oil yield, and composition. However, irrigating Origanum majorana with Biofloc wastewater could be a feasible alternative for the organic production of marjoram and other high-value medicinal herbs in a sustainable approach.