Improving rainfall productivity and oil yield in camelina through the use of plastic mulch and nitrogen

Nitrogen is a factor that significantly impacts plant growth by promoting rapid growth. This study aimed to investigate the oil yield and rainfall productivity of camelina under different levels of nitrogen and mulch. The study was implemented using a split-plot arrangement in a randomized complete block design with three replications at Kermanshah and Kangavar. Nitrogen fertilizer from urea source was tested at four levels (0, 40, 80, and 120 kg N per hectare), while plastic mulch was evaluated at three levels (no mulch, mulch placed over the plants, and mulch laid on the soil). The results indicated that increasing nitrogen fertilizer application and using plastic mulch on soil and plants led to an increase in various parameters including rainfall productivity, protein yield, oil yield, and chlorophyll b content. The highest values of protein yield, oil yield, and chlorophyll b were observed with 120 kg/ha of nitrogen and plastic mulch on soil, while the lowest values of protein yield, oil yield, and chlorophyll b were recorded in the no nitrogen application without plastic mulch (control). Using plastic mulch on the soil along with 120 kg/ha of nitrogen increased oil yields, which was associated with better plant physiological traits such as rainfall productivity, chlorophyll b, and proline. In addition, raising the nitrogen level and applying plastic mulch led to increased carotenoids as well as higher leaf relative water content and greater concentrations of nitrogen, phosphorus, and potassium in camelina seeds. The leaf relative water content with 120 kg/ha of nitrogen was 12.6% higher than in the control treatment. Overall, it is recommended to use plastic mulch on soil with a nitrogen application rate of 120 kg/ha to achieve the highest camelina oil yield under similar climatic conditions.