Effect of irrigation intervals, nitrogen rate and nitrogen splitting on essence of German chamomile (Matricaria chamomilla L.)

In order to determine the best irrigation interval, nitrogen rate and nitrogen splitting on essence of German chamomile (Matricaria chamomilla L.), a field experiment was conducted in the Experimental Field of the Islamic Azad University of Tabriz, in 2006-2007 cropping season. The experiment was established as a randomized complete blocks design using a split plot factorial arrangement and three factors including irrigation intervals (I1=6; I2=12, I3=18 days) in main plots, and factorial combination of nitrogen (urea) rate (N1=50; N2=100, N3=150 kg ha-1) and nitrogen splitting (T1= 100% at planting time; T2= 50%:50% at planting and stem elongation stages, T3= 25%:50%:25% at planting, stem elongation and early flowering stages, respectively) in subplots. Results revealed that application of 100 kg ha-1 and increasing irrigation intervals from 6 to 12 days had positive effect on flower number per plant. The highest dry flower yield (378.8 kg ha-1) belonged to I1N2. Application of nitrogen fertilizer at T2 increased dry flower yield up to 350.5 kg ha-1, in comparison with T1 and T3, respectively. Flower essence content was not affected by nitrogen fertilizer splitting; however, it was affected by two other factors. Essence yield ranged from 1.56 l ha-1 in I3N3 up to 3.63 l ha-1 in I2N2. Nitrogen fertilizer application at T1 and T3, both caused a significant reduction on flower essence.