Growth, yield and volatile oil of Pelargonium graveolens as affected by spraying of moringa leaves extract under different irrigation intervals

Background Essential oil of Pelargonium graveolens plant (Geraniaceae family) is one of the most significant essential oils produced in Egypt for the domestic market and abroad. Plant extracts have been demonstrated to promote plant development by increasing the efficiency with which nutrients are used and by reducing the impact of different biotic or abiotic stresses on plants. Water regime is one of the great important factors that affect plant growth, oil production and the availability and supply of soil moisture not only governed the rate and type of growth but also commanded the availability of plant nutrients. Objective The aim of this work was to choose the most suitable irrigation intervals with the best concentration of moringa leaf extract to obtain strong growth characteristics and a high oil yield and quality of Pelargonium graveolens under drip irrigation system. Materials and methods This study was carried out in the Experimental Research Station of National Research Centre with a factorial experiment in complete block design contains 9 treatments which are the interaction of three irrigation treatments (every 2 days, 3 days and every 4 days) with three levels of moringa leaf extracts (MLE) as foliar application (0, 0.6 and 0.9%) for two cuts during the two successive seasons of 2020 and 2021. Results and conclusion The plants were irrigated every 4 days and sprayed with MLE at concentration 0.9% illustrated positive effect on growth parameters, chemical composition, herb yield per plant (g) and per ha. (ton) as well as essential oil yield. Regarding the effect on essential oil composition the GC-MS analysis revealed that MLE treatment improved the volatile oil constituents and showed that citronellol, α-eudesmol and cis-geraniol are the main components for essential oil of Pelargonium graveolens herb for two cuts.