study the concentration of macroelements in forage mays (zea mays l.) (sc 704) as effected by inoculation with mycorrhizal fungi and azotobacter chroococcum under different levels of nitrogen

nitrogen and phosphorus are two necessary macronutrients for plant growth and yield. these two elements now will be added to soil by chemical fertilizers. this research has been carried out based on randomized completely block design with three replications at markazi provience agricultural research station, iran, during growing season of 2004-2005 to evaluate the effects of azotobacter chroococcum and mycorrhiza (glomus intraradices) as biofertilizers and urea as chemical fertilizers on concentrations of n, p, k, na, ca and crude protein (%) in corn (zea mays l.) shoot tissues and dry matter of corn. azotobacter chroococcum used as two levels (inoculated and uninoculated), mycorrhiza (glomus intraradices) in two levels (inoculated and uninoculated) and urea in four levels (0, 75, 150 and 300 kg.ha-1). results showed that azotobacter chroococcum affected significantly all studied criteria except of k shoot concentration, but mycorrhizan (glomus intraradices) only had a increasing significantly effect on n, k, na and crude protein. the interaction between azotobacter chroococcum and mycorrhiza (glomus intraradices) had the most increasing effect on dry matter, n, na and crude protein. therefore, based on our results it can be concluded that in order to prevent polluting the agricultural soil, environmental and other water supplies from nitrogen chemical fertilizers, application of azotobacter chroococcum or combined with mycorrhizal fungi with 150 kg.ha-1 urea is recommended.