Fertilizers are materials used to provide plant nutrients which are deficient in soils.
Many fertilizers are extracted and purified from natural deposits in the earth. Materials such as sulpomag, muriate of potash and triple super phosphate are all produced from naturally occurring minerals.
Some materials, such as urea and ammonium nitrate are synthetic, but provide plants with the same nutrients that are found naturally in the soil.
The color of fertilizers vary depending on where they were extracted, the degree of purification and the presence of added dyes. For example, muriate of potash can be either red, white or colorless crystals. The color of a fertilizer does not indicate its usefulness, what really matters is its nutrient content.
Many different materials are used as fertilizers. The following are some of the common fertilizers and the nutrients they typically contain. The actual nutrient level can vary depending on the source.