The effects of nitrogen fertilizer on nutrient uptake, physiological traits and yield components of safflower (Carthamus tinctorius L.)

In order to evaluate the effects of nitrogen fertilizer on nutrient status, physiological traits, oil and protein contents of seeds and seed yields of safflower (CV. Gol-Dasht) an experiment was conducted at Mohaghegh Ardabili University experimental farm, Ardabil- Iran in 2009. The experimental treatments were the application of nitrogen fertilizer at five different levels (0, 50, 100, 150 and 200N ha -1 as urea). The result of experiment demonstrated that the safflower's yield components were significantly affected by the application of 150 kg ha -1 nitrogen level comparing to the control (almost 30% ), moreover 100-Seed Weight (100 SW), Cell Memberane Stability (CMS) and the uptake of K and Ca minerals were significantly increased (between 15 to 40%),whereas the highest N uptake, chlorophyll content and the number of seeds per a plant obtained from 200 kg N ha -1 (more than 20%) . The comparison of treatments with control demonstrated that number of heads or capitols per a plant increased from 5.4 to 7.1 at 200 kg N ha -1 . The highest number of seeds per a capitol obtained from 200 kg N ha -1 . Oil content of Seeds decreased (less than 15%). However, the oil content of seeds generally increases with the increase of nitrogen level consumption. Furthermore, considering oil content of seeds there were no significant differences between 150 and 200 kg N ha -1 (increased more that 40 %). Both Protein content and yield enhanced by increase of nitrogen application (improved between 20-40%).