Investigation the effect of using nitrogen on yield and storage compositions of Safflower grain (Carthamus tinctorius L.)

In order to investigate the effect of nitrogen application on improving the yield, grain yield components and changing grain compositions of safflower Goldasht cultivar, this experiment as a randomized complete blocks design was conducted with four replications in research station of College of Agriculture of Mohaghegh Ardabili University in Ardabil province in 2011 cropping year. Treatments of experiment consisted of five levels of nitrogen fertilizer (urea source 46 percent) 0, 50, 100, 150 and 200 kilogram nitrogen in hectare. Results showed that use of different levels of nitrogen fertilizer had a significant effect on measured traits. Consumption of 200 kilogram in hectare nitrogen increased chlorophyll rates (26 percent), potassium (47 percent) and calcium (27 percent) and decreased sodium (39 percent) in plant. Maximum number of head per plant and grain in head obtained from the consumption of 200 kilogram nitrogen in hectare, while the highest 100-grain weight was obtained with consumption 150 kilogram nitrogen in hectare. The lowest and highest grain yield (1729.5 and 3087.9 kilogram in hectare) was observed in lack of consuming fertilizer and application of 200 kilogeram nitrogen in hectare, respectively. Between fertilizer levels of 50, 100 and 150 kilogram nitrogen in hectare, there was no significant difference in oil content, but consumption of 200 kilogram nitrogen in hectare allocated the highest reduction of the oil (25.7 percent). Despite the negative impact of nitrogen consumption on grain oil percent, oil yield increased with increasing fertilizer consumption and its highest amount (794.04 kilogram in hectare) was obtained from using 150 kilogram nitrogen. The grain protein content was increased from 19.40 percent at the control treatment to 25.10 percent in the highest level of fertilizer and also caused increasing in the amount of grains nitrogen. As regards to this point that in the most measured traits there was no significant difference between the rates of 150 and 200 kilogram nitrogen, for this reason in order to reduce economic and environmental costs using 150 kilogram in hectare nitrogen can be recommended.