Mineral Ions in Fertilizers

Nitrogen, phosphorous and potassium make up the primary mineral nutrients found in most fertilizer applications because of the essential roles they play in plant health and growth. Plants can't use these nutrients unless they are available in ionized forms. Ions form when one element or material combines with another and carry either a positive or negative charge. Mineral ions found in fertilizers are similar to those that are found in the soil.

Most soil nitrogen materials come from nitrogen gases in the atmosphere. Plants capture nitrogen minerals from the soil in the form of nitrate and ammonia ions. According to the University of Wisconsin website, nitrates form when nitrogen and oxygen molecules combine. This creates negative-charged ions. Ammonia ions form when nitrogen and hydrogen molecules combine. The resulting ions hold a negative charge. Fertilizer mixes incorporate nitrogen ions by combining nitrogen with these same chemical elements. Ammonium nitrate (NH4NO3), urea (NH4) and anhydrous ammonia (NH3) make up the three types of nitrogen ions found in fertilizers. These chemical compounds all contain nitrogen and hydrogen molecules, as well as oxygen molecules in the case of ammonium nitrate. They differ in terms of how the molecules are arranged and how many of each molecule type is present.

Phosphorous is an abundant mineral that exists in soils, rocks, water and living matter, according to the University of Minnesota Extension website. It naturally combines with oxygen and hydrogen molecules to form mineral ions. When combined with oxygen and hydrogen, phosphorous becomes a phosphate material. According to the University of Wisconsin, fertilizer mixtures typically use phosphorous that comes from rock formations, such as the ores found in North Carolina and Tennessee. Ore materials contain the phosphorous mineral ions used by plants. Some fertilizers also combine ores with other elements, such as calcium, sulfur and fluoride to create a more water-soluble material. Different mixtures can produce different reactions in the soil in terms of increasing or decreasing soil acidity levels.

Potassium minerals naturally exist as ions within the physical environment. According to the University of Minnesota Extension website, potassium is a highly reactive mineral that easily converts into ion form. It appears in soils, water and rock formations by combining with whatever materials, or elements are present within a particular environment. Because of its highly reactive nature, its availability to plants can vary depending on what form it takes. Some forms of potassium become so tightly bound with soil materials that they're unable to circulate through the soil. Other forms easily circulate through the soil by combining with certain materials. Fertilizer mixes can incorporate potassium ions by combining potassium with other materials, such as chloride, magnesium, sulfur, nitrogen and oxygen. These mixtures differ in how quickly they release potassium ions into a soil environment.