The changes of yield and essential oil components of German Chamomile (Matricaria recutita L.) under application of phosphorus and zinc fertilizers and drought stress conditions

In order to investigate the effect of drought stress and phosphorus and zinc fertilizers on physiological traits, yield and essence components of German chamomile (Gural cultivar), a split plot factorial experiment was conducted based on randomized complete block design with three replications at Research farm of University of Zabol in 2013. Drought stress consisted of three levels 75% (control), 50% (mild stress) and 25% of field capacity (severe stress) as main plots, and factorial combinations of three triple superphosphate fertilizer (CaH4P2O8) levels (0, 150, and 300 kg ha−1) and two zinc sulfate fertilizer (ZnSO4H2O) levels (0 and 30 kg ha−1) as subplots. Studied traits were included carbohydrate, prolin, carotenoid, essential oil percentage, essential oil yield, chamanzulene content, β-farenzn, bisabolo oxide A, and bisabolo oxide B. The results showed significant effect of drought stress on all studied traits, whereas application of phosphorus fertilizer was significant on essential oil percentage, essential oil yield, chamanzulene content, β-farenzn, bisabolo oxide A, and bisabolo oxide B, and zinc fertilizer was significant on essential oil percentage, essential oil yield and chamanzulene content. Also can note that high application of phosphorus fertilizer (300 kg ha−1) had negative effects on yield of chamomile. In general, the results suggest that irrigation based on 50% of field capacity with application of 150 kg phosphorus fertilizer ha−1 and 30 kg zinc fertilizer ha−1 can improve essential oil yield and medicine components of German chamomile essential oil.