Effects of Nitrogen and Tillage practices on oil yieldand yield components of different Rape seed(Brassica napus) cultivars

Sweet basil is one of the most widespread spices in the world. Its dried leaves are used commonly as a flavouring in many food products. This experiment was carried out in research farm of Damavand in 2019 to evaluate. Effect of plant density, nitrogen fertilizer and sowing date on yield and chemical composition of essential oil of sweet basil (Ocimum basilicum L.) .The experimental was conducted a factorial using randomized compelet block design with four replication.The factors were three levels of nitrogen fertilizers: N1= application of 50 kg/ha, N2= application of 100 kg/ha, N3= application of 150 kg/ha and three levels of plant densities:P1=5 cm, P2= 10 cm, P3= 15 cm with two sowing date:S1= 25 April, S2= 10 May.In this evaluation, most stage of plant phonology such as plant height, number of leaf, plant dry weight, leaf of stem, leaf area index, yield of essential oil and percentage of methyl chavicol were measured. The results showed that plant height mean with application of 50 kg/ha had superior point and interaction of N3P2S1 was higher than other levels in plant dry weight on the first and second cutting, yield of essential oil on the interaction NS had significant at the 1 % level on the first and second cutting and leaf area index were significant on the intraction of PS and NSP on the first and second cutting %5 level which indicates better performance in nitrogen fertilizer of 150 kg/ha, plant densities of 15 cm and sowing date of 25 April on the first and second cutting.