Weed suppression capacity of camelina (Camelina sativa) against winter weeds: The example of corn-poppy (Papaver rhoeas)

Crop rotation is one of the most relevant tools for Integrated Weed Management (IWM). In semiarid Mediterranean areas, the crop rotation is limited by climatic conditions. Camelina (Camelina sativa (L.) Crantz) is an interesting option to introduce due to its tolerance to cold and drought and because of its short life cycle, which allows a flexible management for weed control. In this study, the capacity of camelina to reduce the growth and seed rain of corn poppy (Papaver rhoeas L.) was studied. The experiment was carried out at the University of Lleida during three seasons (2018-19, 2019-20 and 2020-21). In each season, three camelina varieties (GP204, Sonny and Joelle) and barley were sown on two sowing dates (SD) (between November and February) in 1.5 m wide x 10 m long plots with three replications. Three 0.5 x 0.5 m2 quadrates were established, where five P. rhoeas plants from a natural population were allowed to grow in each SD. Additionally, every season in March, weed surveys were performed to observe the effect of the SD in the weed flora. Results show that delaying the SD effectively controlled winter weeds, including P. rhoeas, which could not establish in the second SD plots. The growth of P. rhoeas in the first SD was reduced similarly in the presence of the crops in 2018-19, but camelina competed better against it in 2020-21, while barley competed better in 2019-20. Due to the short life cycle of camelina and its earlier harvest date, the potential seed production of P. rhoeas was reduced by 34% in 2018-19, 52% in 2019-20% and 70% in 2020-21, while this reduction was of 23% in 2018-19% and 56% in 2020-21 in barley. The capacity of camelina to reduce the presence of corn poppy and its seed production in semiarid conditions should be considered as a tool for IWM.

Automated summary

Camelina is a cold and drought tolerant crop with a short life cycle, making it an effective tool for weed control. Delaying the sowing date can effectively reduce winter weed growth and seed production of corn poppy.