Can vermicompost improve the yield and essential oil of chamomile (Matricaria chamomilla L.) more than N-chemical fertilizer?

Intensive cultivation has led to a rapid decline in organic matter and nutrient levels besides affecting the physical properties of soil. The sustainability of production systems has become an important issue throughout the world. This study assessed the effects of nitrogen fertilizer and vermicompost on chamomile's qualitative and quantitative yield. The investigation was conducted at the Research Fields of Ran Company in Firouzkouh, Iran, in the spring of 2017. Treatments consisted of 1) Control, 2) 100% nitrogen from urea, 3) 100% nitrogen from ammonium nitrate, 4) 75% nitrogen from urea and 25% from vermicompost, 5) 75% nitrogen from ammonium nitrate and 25% from vermicompost, 6) 50% nitrogen from urea and 25% from vermicompost, 7) 50% nitrogen from ammonium nitrate and 25% from vermicompost, 8) 25% nitrogen from urea and 25% from vermicompost, 9) 25% nitrogen from ammonium nitrate and 25% from vermicompost and 10) 100% nitrogen from vermicompost. The results of this investigation showed that the maximum plant height (67.03 cm) and plant weight (93.21 g plant-1) were obtained by 200 kg ha-1 urea. The application of 202.5 kg ha-1 ammonium nitrate + 1.5-ton ha-1 vermicompost, caused maximum flower diameter. The highest fresh flower yield (7539.45 kg ha-1), dry flower yield (1715.93 kg ha-1) and essential oil yield (6.95 kg ha-1) were obtained in plots that received 135 kg ha-1 nitrate ammonium + 3-ton ha-1 vermicompost. It seems using vermicompost could enhance the quantitative and qualitative characteristics of chamomile.