Sixteen chemical elements are required for the growth of all plants: carbon, oxygen, and hydrogen (these three are obtained from carbon dioxide and water), plus nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, zinc, copper, boron, molybdenum, and chlorine. Some plant species also require one or more of the elements cobalt, sodium, vanadium, and silicon.

13 essential mineral nutrien

J. R. Brown (ed.), Recommended Chemical Soil Test Procedures for the North Central Region, Missouri Agricultural Experiment Station, Columbia, 1998