Objective: To investigate the effect of drought stress and organic fertilizer on German chamomile (Matricaria chamomilla) nutrient uptake, leaf chlorophyll content and os-motic adjustment under field conditions.
Methods: This experiment was carried out through a randomized complete block design with a split factorial arrangement of treatments in three replications. The main plots were subjected to the following irrigation treatments: irrigation after 60, 90, 120, 150 and 180 mm evaporation from Class A pan. The sub-plots were treated with three vermi-compost doses (0, 5 and 10 t/ha).
Results: Although drought stress reduced the nutrient percentages in the shoots, appli-cation of vermicompost enhanced the nutrient percentages, particularly when the plants were subjected to moderate to severe drought stress conditions. Moreover, the results of this study showed that the interaction between irrigation treatments and vermicompost rates on leaf chlorophyll content was significant. Comparison between the combined treatments indicated that under normal irrigation and moderate drought stress conditions chamomile plants received 5 and 10 t/ha vermicompost showed significantly higher leaf chlorophyll content comparing to the control treatment.
Conclusions: Totally, organic fertilization by vermicompost could partly alleviate the effect of drought stress on chamomile by increasing N, P and K uptake and leaf soluble sugar, especially in stressed treatments.

Objective To investigate the effect of drought stress and organic fertilizer on German chamomile (Matricaria chamomilla) nutrient uptake, leaf chlorophyll content and osmotic adjustment under field conditions. Methods This experiment was carried out through a randomized complete block design with a split factorial arrangement of treatments in three replications. The main plots were subjected to the following irrigation treatments: irrigation after 60, 90, 120, 150 and 180 mm evaporation from Class A pan. The sub-plots were treated with three vermicompost doses (0, 5 and 10 t/ha). Results Although drought stress reduced the nutrient percentages in the shoots, application of vermicompost enhanced the nutrient percentages, particularly when the plants were subjected to moderate to severe drought stress conditions. Moreover, the results of this study showed that the interaction between irrigation treatments and vermicompost rates on leaf chlorophyll content was significant. Comparison between the combined treatments indicated that under normal irrigation and moderate drought stress conditions chamomile plants received 5 and 10 t/ha vermicompost showed significantly higher leaf chlorophyll content comparing to the control treatment. Conclusions Totally, organic fertilization by vermicompost could partly alleviate the effect of drought stress on chamomile by increasing N, P and K uptake and leaf soluble sugar, especially in stressed treatments.