Quantification the effects of reduced herbicide doses and nitrogen levels on wheat-Avena ludoviciana Duriu competition

A better understanding of factors affecting competition between wheat and weeds can facilitate the development of more effective crop management methods. In order to quantification wheat- Avena ludoviciana Duriu competition in response to nitrogen and Othello OD herbicide. A field experiment in 2018-19 was conducted as split plots in a randomized complete block design with four replications at Agricultural Sciences and Natural Resources University of Khuzestan. Nitrogen fertilizer in included five levels of 0, 80, 160, 240 and Unconventional consumption 320 kg ha-1 of Nitrogen fertilizer was considered as the main plot and the herbicide dose of Othello OD herbicide in five levels of 0, 0.25, 0.5, 0.75, and 1 times the recommended dose (The recommended dose of herbicide is 1.6 L ha-1) was considered as the sub plot. The results showed the dose required for 50% reduction of weed biomass in non-fertilized conditions, was equal to 75% of the recommended herbicide was used. That with increasing nitrogen fertilizer consumption led to lower herbicide dose. So that by consumption 320 kg N ha-1 reached 37% of the recommended dosage of this herbicide. Also, to achieve about 700 g m-2 of wheat biomass, using 185 kg ha-1 of nitrogen fertilizer plus 85% of the recommended herbicide dose, or applying 320 kg ha-1 of nitrogen fertilizer and 65% of the recommended dose of herbicide.