Effects of Zeolite, Bio- and Organic Fertilizers Application on German Chamomile Yield and Essential Oil Composition

Abstract

The current study was carried out to investigate the influence of zeolite, vermicompost and PGPRs on German chamomile (Matricaria recutita L.) flower yield, essential oil contents and components in a semi-arid region of Iran, during 2013 and 2014 growing seasons. The experiment was conducted using a randomized complete-block design arranged in factorial scheme with three replicates. The first factor consisted of three vermicompost rates 0, 5, and 10 t ha−1, the second factor included two amounts of natural zeolite 0 and 9 t ha–1 and the third factor consisted of two levels of plant growth-promoting rhizobacteria (PGPRs) treatments, non-inoculated and inoculated seed. In addition, in each block, one plot was considered as the mineral fertilizer (as control treatment). The results indicated that application of organic fertilizers caused the highest flower yield in both years (464 and 521 kg ha−1 in 2013 and 2014, respectively). The result of GC and GC-MS analysis showed that the oil of German chamomile flowers which harvested in the chemical and organic fertilizer treatments had 14 and 16 components, accounting for 88.74 and 97.30% of total essential oil in these treatments, respectively. The major constituents of essential oil in the chemical fertilizer treatments were α-bisabolol oxide A (34.5%), α- bisabolol (30.2%), chamazulen (6.27%), E-β-farnesene (5.10%) and α-bisabolol oxide B (4.50%), while in the organic fertilizer treatments were α-bisabolol oxide A (44.1%), α-bisabolol (30.7%), chamazulen (6.41%), α- bisabolol oxide B (5.25%) and β-Bisabolene (3.64%). From this work, it can be concluded that the application of vermicompost, zeolite and PGPRs could be critical in the cultivation of German chamomile in arid and semiarid conditions, where soil fertility is one of the most important factors limiting plant growth, yield and quality.