Influence of nitrogen and plant density on spring wheat (Tritium aestivum L.) and oat (Avena ludoviciana L.) competitiveness

The researches have shown increased plant density and nitrogen fertilizer may be an important component of integrated weed management programs. A field study was conducted to determine the effect of various plant densities and nitrogen fertilizer on spring wheat and wild oat competitiveness. The treatment were consisted of three levels of nitrogen (100, 150 and 190 kgNha -1 ) and four crop sowing densities (400, 500, 600 and 700 plant m-2) of spring wheat. The experimental design was factorial with three replications. Increased nitrogen rates up to 150 kg N/ha caused an increase in wheat grain yield in weedy plots. Nitrogen fertilization increased wild oat and spring wheat biomass. Increased plant densities caused significantly reducing spring wheat yield loss, wild biomass and seed production. The effects of nitrogen fertilizer on weed suppression were influenced by plant density. The result indicate that increased plant density and nitrogen fertilizer can improve spring wheat competitiveness and reduce grain yield loss, wild oat seed production and biomass. * Corresponding Author: Abdol Karim Banisaeidi  a.banisaeidi@yahoo.com