the effect of different levels of nitrogen and copper on yield and nutrients concentrations and nitrate broccoli head (brassica oleracea)

in order to study the effect of different levels of nitrogen and copper on yield and nutrients concentrations and nitrate in broccoli head, an experiment was conducted based on a factorial combinations of five levels of nitrogen (0, 100, 200, 300 and 400 kg/ha) and three levels of copper (0, 2.5 and 5 kg/ha) that were applied to soil as ammonium sulfate and copper sulfate respectively, in three replications in greenhouse of zanjan university in 2010. results showed that application of nitrogen and copper increased head yield and quality of broccoli. the application of 300 kg n + 2.5 kg cu/ha resulted in highest yield of broccoli head. the highest concentration of nitrogen in broccoli head was measured in treatment with 400 kg n+ 2.5 kg cu/ha. the highest concentration of nitrate in broccoli head was measured in treatment with 300 kg n/ha and without use of copper. also, application of higher amount of copper decreased nitrate concentration in broccoli head. the highest concentrations of potassium and calcium in head were obtained with application 300 kg n + 2.5 kg cu/ha. the results showed that application of nitrogen and copper in optimum levels increased head yield and nutrients concentrations in broccoli head.