Fertilizers Fertilizers are available in many different forms and combinations. Many of the terms used are confusing and misleading. A fertilizer analysis, the relative percentages of these three nutrients, is listed on the label and is referred to as the NPK number. Incomplete fertilizers only contain one ro two of the primary nutrients. These are not lesser fertilizers, but are used to correct specific deficiencies.
Fertilizers are also available in organic and inorganic forms.
An organic fertilizer is made from natural sources, such as plants, animals, and unprocessed minerals. They contain carbon compounds and may also contain certain amounts of inorganic materials. They are generally slower in releasing their nutrients to the soil. Ammoniacal, Urea, and Nitrate nitrogen are inexpensive, synthetic, water-soluble sources of nitrogen. Chelates or chelated micronutrients are water soluble compounds that are readily available to the plants and may be applied by foliar or soil sprays.