Effect of different nitrogen doses on corn weed competition

Objective: In this study, it was aimed to determine the nitrogen doses that keep the corn yield at the highest level with the effect of different nitrogen doses and producer application on weeds and yield components in corn under weed competition. Material and Methods: In addition to the nitrogen doses (0, 12, 24 and 48 kg da-1) used in pot studies, producer practice was also included in field studies. Plant height, fresh and dry weights were evaluated in pot studies, weed density, coverage area, fresh and dry weights and some yield and yield parameters of corn were evaluated in field studies. Results: In pot experiments, it was determined that nitrogen treatments had a positive effect on the growth of either corn or weeds. However, in field experiments, nitrogen treatments had a positive effect only on yield components of corn. In the evaluation of weeds in field studies, it was determined that purslane and jimsonweed gave variable results to nitrogen applications, while barnyard grass and johnson grass did not show a positive or negative reaction to nitrogen applications. As a result, it was determined that the application providing the highest yield in corn was 48 kg da-1 nitrogen application or grower's application (50 kg da-1 15:15:15 NPK application with planting, 20 kg da-1 N application using urea fertilizer with hoe and 40 kg da-1 ammonium sulfate application with first irrigation). Conclusion: It has been determined that nitrogen applications benefit corn more than weeds in the weed densities evaluated in the study, it can benefit from more nitrogen than corn in areas with high density of jimsonweed, and the use of 24 kg da-1 nitrogen application is more preferable considering the profit and loss relationship.