Effect of temperature degree, different nitrogen levels and plant density on oil yield of spring Safflower

The present study was performed with use of Esfehan variety in the research field of Arak Azad University in the 2009 agricultural years. This experiment was performed in factorial split plot in randomize complete block design in 4 Replication and 48 plot. Treatment included two planting date 10 may and 10 July(delayed plant) and different level of N include (46¡92¡138)kg per hectare and two plant density included 400.000 and 800.000 plant per hectare that 800.000 plant per hectare executed in double row planting. the result of this study showed that the highest yield of the 821.17 oil per hectare was related to the treatment of date of planting 10 may with 92 kg N and plant density of 800.000 per hectare. Also¡ the lowest yield of 444.42 kg/h was related to the date of planting 10 may with 92 kg N and 400.000 plant density per hectare¡ Therefore¡ plant density has very influence on the yield of safflower. So¡ according to the result¡ 800.000 plant density in per hectare has direct effect on the yield of safflower rather than 400.000 plant density.