There are 10 major or macro nutrients required by plants. These include Carbon (C), Oxygen (O), and Hydrogen (H)--from air and water; Nitrogen (N), Potassium (K), and Phosphorus (P)--from inorganic fertilizer and organic matter; and Calcium (Ca), Magnesium (Mg), Sulphur (S), and Chlorine (Cl)--from gypsum, limestone, dolomite, and fertilisers. Most plants have the highest requirement for carbon, oxygen, and hydrogen, followed by nitrogen, potassium, and phosphorus.


Source: Better Soils [Online]. 1997. Module 2: Soil Nutrition and Crops. Agricultural Bureau of South Australia. Adelaide, SA. Available at (verified 19 August 2004).