Fertilizers are chemical compounds applied to promote plant and fruit growth. Fertilizers are usually applied
either through the soil or, by foliar feeding for uptake through leaves. Inorganic fertilizers are composed of
simple chemicals and minerals, the major nutrients being nitrogen (N), phosphorous (P) and potssium (K).
Inorganic fertilizers are labeled according to the relative amounts of each of these three elements, by
weight. Potassium is reported as the mass fraction of potassium oxide (K2O).