The Response of Coriander (Coriandrum sativum L.) in Different Plant Densities to the Using of Nitrogen Fertilizer

Application of proper rates of nitrogen fertilizer and plant density are important factors for medicinal plants yield. To study the effect of nitrogen rates and plant densities on yield and yield components of coriander, an experiment was carried out in split-plot based on randomized complete block design with three replications at the Research Field of Islamic Azad University of Birjand, Iran, in 2013. The main plots were nitrogen rates with four levels (0, 40, 80 and 120 kg N per ha) and the sub-plots with three levels (30, 40 and 50 plants per m2). The results showed that nitrogen rate had significant effect on number of umbel per plant and per m2, fruit number per umbel, fruit yield, biological yield, fruit weight of single plant, biomass yield of single plant and percent and yield of essential oil. Changes in plant density, also had significant effect on all traits except fruit number per umbel, 1000-fruit weight and percent of essential oil. Moreover, interaction effect between nitrogen rate and plant density affected all traits except umbel number per plant, fruit number per umbel and percent and yield of essential oil. Mean comparisons showed that as N fertilization rate increased from 0 to 80 kg N ha-1, umbel number per m2, fruit yield, biological yield and essential oil yield increased by 62.5, 74.1, 74.3 and 186.8%, respectively. Results also revealed that increasing plant density from 30 to 50 plants per m2, increased these traits by 25.6, 31.4, 21.8 and 37.4%, respectively. The conclusion is that application of 80 kg N ha-1 and use of 50 plants/m2 produced highest fruit and essential oil yield for coriander in Birjand region