Evaluation of radiation absorption and use efficiency of winter wheat (Triticum aestivum L.) and wild oat (Avena ludoviciana L.) in nitrogen fertilizer levels and wild oat additive densities

Some essential factors effectively reduce wheat yield; one of the most critical factors is weeds. The effect of this factor can vary at different fertilizer levels. To investigate the effect of different densities of wild oat in different nitrogen fertilizer levels on the wheat traits, an experiment was conducted in the form of split plots and in a randomized complete block design with three replications. Treatments included the application of 30, 60, 100 and 120% of wheat nitrogen fertilizer requirement and densities of zero, 25, 50, 75 and 100 wild oat plants per m2. The results showed that the highest wheat grain yield (871.60 g/m2) and radiation use efficiency (1.49 g Mj-1) obtained at 120% fertilizer level and the absence of weeds, and the lowest obtained at 30% nitrogen and 100 plants per m2. The highest dry weight yield (381 g/m2) and radiation use efficiency (1.6 g Mj-1) of wild oats were obtained at 100 plants/m2 density and at the highest level of nitrogen fertilizer. In general, increasing the presence of wild oats and increasing its density under conditions of improper application of nitrogen can intensify interspecific competition and ultimately lead to yield reduction.