Two year field trials were carried out during 2016 and 2017 seasons to evaluate the effect of some nutrient foliar spray treatments i.e. the combination of Ca +Mg at 50,100 and 150 ppm, beside the combination of micronutrients i.e. Fe +Mn +Zn at 50, 100 and 150ppm and Lithovit at 0.5 and 1g/L four times a year on vegetative growth, essential oil yield and constituents and some chemical constituents of Cymbopogon citratus plants. Results showed that different applied treatments of some nutrients treatments led to significant increase of the studied parameters i.e. plant height, fresh and dry weights of herb/(g/plant), and No. of tiller /plant. However, the tallest plant, was recorded by 150ppm Fe +Mn +Zn -sprayed plants, whereas the heaviest fresh and dry weights of herb/(g/plant) and the highest number of tiller /plant were scored by lithovit at 1g/L in both cuts and in the two seasons. Moreover, the highest values of N, P, K and total carbohydrates contents were registered by lithovit at 1g/L treatment in both seasons and in the two cuts. In addition, spraying Cymbopogon citratus plants with 150 ppm Fe +Mn +Zn treatments gave the highest leaf Fe, Zn and Mn content, while the richest leaf total chlorophylls, Ca and Mg contents were recorded by Ca +Mg at 150ppm treatment at the both cuts in the two seasons. Furthermore, leaf essential oil percentage scored the highest values when plants were sprayed with the high concentration of Fe +Mn +Zn (150ppm). Six compounds of volatile oil of Cymbopogon citratus plant were identified. The main component was the citral A (Geranial), that ranged from (46.05 to 50.22 %) followed by citral B (Neral) (30.35 to 32.30) and β-Myrcene (9.35 to 10.03%). Consequently, it is preferable to spray Cymbopgon citruts plants with lithovit at 1g/L or 150ppm Fe +Mn +Zn four times a year to enhance the growth, essential oil yield and constituents and some chemical constituents of this plant |
