In saline conditions the first sign in leaves is a yellowing of leaves. A foliar spray is made of 1 ounce on sodium or ammonium molybdenate in 100 gallons of water. Phosphate fertilizers usually have enough molybdenum as an impurity to act as a molybdenum supplement for soil or nutrient water. It is used in an enzyme, xanthine oxidase that aids in mobilization of iron from liver, and gathers excess nitrogen in the body turning it into uric acid. Grains, legumes and dark green leafy vegetables are rich sources.
Amounts differ due to amount available in soil.
Since so little molybdenum is needed by the human body, a deficiency is rare. When it is induced in research, it looks like anemia, or iron deficiency. In a hydroponic nutrient, molybdenum should be added at a rate of 1 microgram per liter of solution. This allows for enough molybdenum to grow a large crop and still includes enough molybdenum for human nutriention.