fertilizer
A fertilizer ( American English ) or fertiliser ( British English ; see spelling differences ) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients . Fertilizers may be distinct from liming materials or other non-nutrient soil amendments . Many sources of fertilizer exist, both natural and industrially produced. [1] For most modern agricultural practices, fertilization focuses on three main macro nutrients: Nitrogen (N), Phosphorus (P), and Potassium (K) with occasional addition of supplements like rock dust for micronutrients. Farmers applying these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment or hand-tool methods. Historically fertilization came from natural or organic sources: compost , animal man...