This study carried out at a private farm in Elmhamid village ,Arment district , Luxor governorate, Egypt in 2016/2017 and 2017/2018 growing seasons for determine the effect of plant densities , different nitrogen sources and doses on the safflower cv. Giza (carthamus tinctorius) morphological and physiological characteristics.
The experimental design was split-split plot set up with three replicates in both studied seasons was followed. The main plots were devoted to three plant densities viz, 35, 47 and 70 thousand plants/fad., and sub-plots were allotted to the three forms of nitrogen, i.e. ammonium sulphate, ammonium nitrate and urea, while the four nitrogen fertilizer levels were randomely arranged in the sub-sub-plots. The highest plant density of 70000 plants fad.-1 recorded the highest values of plant height and LAI at the growth stages i.e 65, 86 and 107 days from sowing in both seasons, while, the lowest plant density of 35000 plants/fad.-1 recorded highest values of number of green leaves plants/fad.-1 , number of branches plants-1, dry weight plants-1(gm) and leaf area plants-1in the three growth stages in both growing seasons.
The nitrogenous fertilizer forms had a significant effects on plant height at 107 days in the two growing seasons, But the other studied traits not show any significant response by the studied treatments under the two growing season at any growth stages . The highest values were recorded by using urea as the best form of nitrogen fertilizer under this experiment conditions.
The nitrogenous fertilizer levels had a significant effects on all studied traits at the different growth stages and the two growing seasons indicated the important of nitrogen fertilization on safflower under site of experiment.
Conclusively, from these results it could be concluded that to increase the number of branches' / plant and leaf area index should be apply 60kg/fed level of nitrogen with low plant density.