Effect of sowing date and application of foliar fertilizers on the yield and chemical composition of rue (Ruta graveolens L.) herb
The present investigation was conducted during two successive seasons of 2004/2005 and 2005/2006 in order to study the effect of two different sowing times and two macro- and microfoliar fertilizers on yield and chemical composition of Ruta graveolens plants. Delay in sowing from 20 October to 20 November resulted in significant promotion for herb dry weight (g/m2) as well as percentage and yield of essential oil of herb. In contrast, the accumulation of rutin and coumarin contents was higher at the first sowing time than the second one. The main constituent of essential oil in herb was identified as 2-undecanone. It represented 60.74% of identified herb essential oil at first sowing date and decreased to 55.88% at second date. Both foliar fertilizers, Crestalon and Leaf drip, promoted herb dry weight. Leaf drip was more favorable to improve these criteria than Crestalon. In general, the highest content of essential oil, rutin and coumarin were recorded with application of 1000 or 2000 ppm of Leaf drip. The maximum yield of herb and essential oil resulted in plants of the second date of sowing and fertilized with Leaf drip at 2000 ppm.