Objective The purpose was to study the absorption and utilization law of cobalt and the interrelationship among trace elements in Alfalfa.Method In the leaf spraying experiment,cobalt sulfate spraying was set at 3 cobalt levels:100,300 and 600 mg/kg to study the effects of applying cobalt with different levels on the dry grass yield,trace elements contents and accumulation amount of Alfalfa.Result Spraying cobalt sulfate could significantly increase dry grass yield of Alfalfa,in which the effect of treatmen...