The effects of water deficit and nitrogen levels on yield and yield components of winter canola in Urmia, Iran - TI Journals

Abstract: Canola as a member of the mustard family is one of the main sources of vegetable oil in the world. In addition to oil production, the leaves and stems of canola provide high quality forage suitable for animal feeding because of their low fiber and high protein contents. Recently the cultivation of canola is developing more and more in Iran. The main purpose of this study is the investigation of yield and yield components of canola under the simultaneously water stress and nitrogen levels. This research was carried out during the growing season of 2012-2013 in the agricultural research station of Urmia University located in Urmia lake basin, Iran. The planted cultivar was, Okapi, winter type of canola. Three nitrogen levels (60, 120, and 180 kg N /ha as urea 46%) and three irrigation treatments (applied water at 1.0, 0.75, and 0.50 ratios of potential canola water requirements as I1, I2, and I3 treatments, respectively) were considered. The potential water requirements were estimated based on the differences between soil field capacity and measured soil water contents at root depth in the I3 treatments before each irrigation. The obtained results showed that the yield and yield components of canola were decreased under water stress condition. Of course, fertilization largely improved the product decrement due to water stress. The maximum seed yield was obtained 4.53 Mg/ha by irrigating the field up to field capacity and using 180 kg N/ha fertilizer. Among the characters, the number of branches in stem had the least variation due to the water and fertilizer different levels. The plant height, stem diameter, number of pods and the number of seeds in each pod, were more sensitive to water shortage than fertilizer levels. Using the results of this paper, it is possible to solve the problems of canola yield due to water shortage, by using fertilizer and adequate nourishing of soil.