This section briefly describes the major and minor nutrients required by all crop plants. The following section, Fundamentals of Soil Health and Soil Fertility Management, addresses the responsible application of fertilizers and soil amendments and stewardship of soils to economically and efficiently provide plant nutrients while minimizing losses and subsequent negative environmental effects. The third and fourth sections, Soil Testing and Fertilizers and Soil Amendments, describe soil testing methods and the many inputs commonly used to provide crop nutrient needs.
An element is considered essential to plant growth if it becomes part of plant tissue or is involved in metabolic functions and the plant cannot complete its lifecycle without it. There are 17 elements currently considered essential to plant growth. Listed in order of abundance in plant tissue, the 17 essential elements are: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Potassium (K), Calcium (Ca), Magnesium (Mg), Phosphorus (P), Sulfur (S), Chlorine (Cl), Iron (Fe), Boron (B), Manganese (Mn), Zinc (Zn), Copper (Cu), Molybdenum (Mo), and Nickel (Ni). Plants obtain C, H, and O from air and water during photosynthesis. Together, these three elements make up approximately 95% of a plant's dry matter. Plants obtain the other 14 essential elements, called mineral nutrients, from soil. The mineral nutrients are classified as either macronutrients or micronutrients based on their relative abundance in plants. The six macronutrients, required in relatively large quantities, are N, P, K, S, Ca, and Mg. The eight micronutrients, required in relatively small quantities, are Cl, Fe, B, Mn, Zn, Cu, Ni, and Mo. Other nutrients, such as Silicon (Si), have shown to be beneficial in crop growth and disease suppression, but are not essential for the plant to complete its life cycle.