ABSTRACT
This study was carried out at the Department of Ornamental Horticulture, Faculty of Agriculture, Cairo University during the two successive seasons of 2015 and 2016. The experiment was designed using a complete randomized blocks design. The objective of this study was to investigate the effect of NPK (recommended dose), biofertilizers (Nitrobien and Phosphorien) at 1,2 and 4 g/plant, compost and poultry manure at the rates of 5, 10 and 15 ton/ feddan (feddan=4200 m2) on essential oil production and biochemical compositions of Cymbopogon citratus plants. The results showed that the average percentage of essential oil ranged between 0.140-0.300% at the first cut and 0.133-0.283% at the second cut of the two seasons, respectively. First cut (in August) resulted in more essential oil production than second cut (in October). Poultry manure produced the maximum essential oil yield/plant compared to control and the other fertilizer treatments. The main components in essential oil of lemongrass were β. myrcene, linalool, neral (citral b), geranial (citral a) and geranyl acetate identified by GC. Arranged in descending order, the major constituents were citral a and citral b which reached to 69.72- 81.39% in the oil. Compost at the rate of 10 ton/ feddan was the most effective application in citral content which reached to 81.39%. The organic applications positively affected pigments content of lemongrass plant. The highest herb content of phosphorus and potassium resulted from the plants treated by compost at the rate of 10 ton/ feddan and nitrobien at the rate of 2 g/plant.