Effect of nitrogen and herbicide application on competition between wheat and wild oat

To study wheat-wild oat competition in response to nitrogen and herbicide, an experiment was carried out in 2007-2008 cropping season in Agriculture and Natural Resources University of Ramin, North of Ahwaz, Iran. A split plot arrangement in randomized complete block design with three replications was used. The nitrogen levels(0, 60, 120 and 180 kg.ha-1) were assigned to main plotsand four herbicide levels (0, 0.8, 1.0 and 1.2 lit. Clodinafob Propargile.ha-1) hand weeding (control) were randomized in subplots. Results showed that nitrogen × herbicide interaction was significant on grain yield and dry matter of wheat and wild oat.Grain yield and dry matter of wheat significantly decreased with increasing nitrogen at lower herbicide levels. However, theapplication of higher doses of herbicide at higher nitrogen levels reduced grain yield and dry matter of wheat. IHowever, at lower nitrogen levels there was not significant difference between herbicide doses. Increasing nitrogen without herbicide or at lower level of herbicide doses also significantly increased dry matter of wild oat. The highest grain yield of wheat (4715.5 kg.ha-1) and lowest dry matter of wild oat (without weed) were obtained in 180 kg ha-1 of nitrogen and 1.2 lit.ha-1 of herbicide. The negative and significant correlation between dry matter production of wheat and wild oat, showed a rationale relationship between nitrogen and herbicide levels in term of competition between wheat and wild oat and dry matter production of them. This case showedprobability of application of nitrogen interaction with herbicide in integrated management of wild oat in wheat cultivation.