Fertilizers are pure substances and mixtures of substances that supplement the nutrient supply of cultivated plants. They are used in agriculture, forestry and horticulture. In addition to heat, light, air and water, plants also need nutrients for their growth. These include, among other things, minerals that control and support the growth and development of plants.

In the soil, nutrients are often not available in the form and quantity that would be optimal to be used by plants. They are either naturally not present in sufficient quantities, are removed from the soil by harvested products or are shifted in the soil. The supply of plant nutrients in the form of fertilizers makes it possible to compensate for such a lack of nutrients. Fertilization is applied according to the nutrient conditions in the soil and plant requirements. Fertilization improves plant nutrition, promotes plant growth, increases yield, improves crop quality, and ultimately preserves and promotes soil fertility.