Two field trial were conducted at Sakha Agricultural Research Station, Kafr El-Sheikh Governorate, Egypt, during
2016/2017 and 2017/2018 winter seasons to study the physiological response of flax (Linum usitatissimum L.) Sakha 3,
cultivar to three nitrogen fertilizer rates i.e; 25, 35 and 45 kg N/fad.. in a combination with foliar spray by urea 2(%) plus
some of micronutrients mixture of (Fe + Zn + Mn) using concentration at 200 ppm for each element. The maximum
values of plant height, fruiting zone length, technical length, as well as, leaf area/plant and dry matter accumulation (g)/m2
at 80 and 95 days after sowing (DAS), crop growth rate (CGR) and net assimilation rate (NAR) at (80–95 DAS) period
were obtained when plants received 35 kg N/fad. and foliar spray with urea 2(%)plus 200 ppm micronutrients mixture of
(Fe + Zn + Mn). In addition, straw and seed yields, its components, fiber (%), fiber yield, total chlorophyll of leaves at 95
DAS, oil (%) and oil yield.
The total saturated fatty acids of flax oil were, gradually, increased with increasing nitrogen fertilizer rate from 25 up
to 45 kg N/fad., whereas, the total unsaturated fatty acids were decreased. The minimum value of the total unsaturated
fatty acids were obtained from plants received [35 kg N/fad. and a spray with 200 ppm micronutrients mixture of (Fe+ Zn
+Mn)].