The Effect of Nitrogen Rate and Plant Density on Morphological Traits and Essential Oil Yield of Coriander

In order to study the effect of nitrogen rate and plant density on morphological traits and essential oil and fruit yield of coriander, a split-plot experiment was carried out in research field of Islamic Azad University, Birjand Branch, Birjand, Iran in 2010 based on a randomized complete block design with three replications. The main plots were nitrogen rates at four levels (0, 40, 80 and 120 kg N/ha) and the sub-plots were plant densities at three levels (30, 40 and 50 plants/m2). The results showed that nitrogen rate had significant effect on fruit yield, essential oil percent and yield traits and interaction between nitrogen rate and plant density only affected fruit yield but change in plant density significantly affected all traits except essential oil percent. Means comparison showed that as N fertilization rate was increased from 0 to 80 kg N ha-1, plant height and fruit yield were increased by 19.8 and 74.1 %, respectively. Also, essential oil percent increased from 0.153 to 0.33% and essential oil yield was greater 2.68 times. Moreover, means comparison showed that the increase in plant density from 30 to 50 plants/m2, increased plant height, first fruit distance from ground, fruit and essential oil yield by 14.3, 27.6, 31.3 and 36.8%, respectively while stem diameter and branch number per main stem were decreased by 22.2 and 13.9%, respectively. Given the results of the study, the treatment of 80 kg N/ha application with the density of 50 plants/m2 recommended for the cultivation of coriander in Birjand, Iran.