Therefore adding additional nutrients will not result in crop response but may contribute to environmental degradation. Knowing where not to apply fertilizer is as important as knowing where fertilizer is needed. Inorganic fertilizers Fertilizer can be thought of as any type of material used to supply one or more of the plant essential elements. Traditionally these materials fall into two categories - inorganic or organic. Inorganic fertilizers are chemically much simpler than organic fertilizers and are obtained from non-living sources.
Most inorganic fertilizers are synthetic.
For example, granular nitrogen fertilizer is made by combining nitrogen in the air with hydrogen from fossil fuels or water with various other substances. Fertilizers such as rock phosphate and potash occur naturally in deep deposits and are mined, sized and cleaned. Rock phosphate is simply further acid-treated to produce highly soluble triple superphosphate. Most plant nutrients in commercial fertilizers are in the form of moderately to very soluble salts. These salts dissolve rapidly in water to form ions.