Compound fertilizers are available in two categories: organic and inorganic. The organic compound are normally made out of manure, fish bone, bone meal, including compost, whereas inorganic compound fertilizer are made from various chemicals in the manufacturing process.
These compound are available in either liquid or granular form, and some granular fertilizer is in a slow-release formula. Compound fertilizer mainly contains two or more essential plant nutrients. Aside from that, the compound fertilizer also contains secondary and trace elements.
Typically, fertilizers must have these three essential nutrients: Nitrogen(N), Phosphorus(P) and Potassium(K). These nutrients are essential for plants to complete their life cycle. Secondary nutrients are: Calcium(Ca), Sulfur(S), and Magnesium(Mg) which are normally present in the soil but need to be replenished periodically. And trace elements consists of nutrients such as Boron(B), Copper(Cu), and Cobalt(Co).