Introduction: Producing oil from plant sources such as oil crops and obtaining high level of oil ‎production from them is influenced by many factors, among which the physical and chemical ‎properties of the soil are of great importance. For this purpose, the recommendation to use the ‎optimal amount of fertilizers to achieve the highest yield should be considered. Camelina sativa has ‎attracted the attention of many researchers, especially in semi-arid regions, due to its adaptive ‎characteristics such as tolerance to cold and drought stress. It has been reported that camelina can ‎survive temperatures below -11°C and can also be grown in areas with moderate rainfall throughout ‎the growing season. Plastic mulch (polyethylene, PE), which has been a favorite of many producers ‎in the past decades, is among the agronomic practices through which moisture is conserved for use ‎during the expected dry season.‎

Material and methods: This study was conducted in two counties located in Kermanshah province ‎‎(County 1: Kermanshah and County 2: Kangavar) and a split plot experimental design was used. ‎The cumulative rainfall during the growing season was 476.5 mm in County 1 and 343.6 mm in ‎County 2. The planting date in the fall was determined based on surveys so that the plant escapes ‎from the heat of the end of the growing season. Camelina seeds were planted after performing a ‎germination test, resulting in a germination percentage of 89%. In order to find the optimal rate of ‎nitrogen fertilizer utilization, four levels of nitrogen input including 0, 40, 80 and 120 kilograms per ‎hectare were applied (F1, F2, F3, F4). To find the best way of applying plastic mulch for camelina ‎cropping, three levels of polyethylene plastic mulch (PE) including no PE, PE on the plants and PE ‎on the soil surface were surveyed (M1, M2, M3). Nitrogen was applied in three phenological stages ‎including 4 leaves appearance, beginning of stem growth and beginning of reproductive stage. In ‎this research, transparent polyethylene plastic with a UV grade of 10 and a thickness of 40 microns ‎was used. Some morphophysiological aspects of camelina growth were evaluated including: plant ‎height, stem diameter, number of leaves, leaf area index (LAI), leaf area duration (LAD), number of ‎lateral shoots, yield components and seed yield. Sampling for evaluating morphological properties ‎of camelina was conducted when 50% of the panicles appeared. ‎

Results and Discussion: The result of this study indicated that using plastic mulch and also applying ‎optimal rate of nitrogen fertilizers can be useful to achieve the satisfying values of production in ‎camelina cropping systems. The highest plant height was recorded when using PE mulch on the soil ‎with applying 120 kilograms of nitrogen per hectare (118.2 centimeter) while the lowest plant height ‎was recorded when no-PE and no nitrogen was used (control treatment). Appling 80 and 120 ‎kilograms per hectare of nitrogen enhanced the stem diameter significantly. The highest leaf area ‎index was recorded using 120 kg/ha of nitrogen and polyethylene mulch at the soil surface (4.03). ‎The leaf area index was significantly minimal in conditions where there was no nitrogen and ‎polyethylene mulching treatment (control treatment). Minimum seed yield was recorded under ‎control treatment (68 gr/m2) and the maximum value was recorded when using PE mulch on the soil ‎surface and applying 120 kg/ha nitrogen input. ‎

Conclusion: The overall results of this study indicate that to achieve the highest seed yield of C. ‎sativa in climatic conditions such as the two counties in this study, the use of nitrogen fertilizer at a ‎rate of 120 kg/ha with the use of polyethylene mulch on the soil surface are recommended.‎