If a plant shows a symptom which could develop due to deficiency of more than one nutrient

If a plant shows a symptom which could develop due to deficiency of more than one nutrient, how
would you find out experimentally, the real deficient mineral element?

Every element shows certain characteristic deficiency symptoms in the plants.
The deficiency of any one element cannot be met by supplying some other element. So, by absorbing the type of deficiency symptom, we can determine the real deficient mineral element.